4ac39048706e38815cd6784244a4e1eebc72eff0 |
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03-Jun-2015 |
Christian Poetzsch <christian.potzsch@imgtec.com> |
Fix generic cgroup subsystem permission checks In 53b5e2f generic cgroup subsystem permission checks have been added. When this is been done within procs_write an empty taskset is added to the tasks css set. When a task later on migrates to a new group we see a dmesg warning cause the mg_node isn't empty (cgroup.c:2086). Cause this happens all the time this spams dmesg. I am not really familiar with this code, but it looks to me like adding the taskset is just a temporary action in this context. Therefore this taskset should be removed after the actual check. This is what this fix does. This problem was seen and the fix tested on x86 using l-mr1 and master. Change-Id: I9894d39e8b5692ef65149002b07e65a84a33ffea Signed-off-by: Christian Poetzsch <christian.potzsch@imgtec.com>
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53b5e2f0b1cebfd3493ba8ba3bb9d14924a9fa11 |
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13-Jul-2011 |
Colin Cross <ccross@android.com> |
cgroup: Add generic cgroup subsystem permission checks Rather than using explicit euid == 0 checks when trying to move tasks into a cgroup via CFS, move permission checks into each specific cgroup subsystem. If a subsystem does not specify a 'allow_attach' handler, then we fall back to doing our checks the old way. Use the 'allow_attach' handler for the 'cpu' cgroup to allow non-root processes to add arbitrary processes to a 'cpu' cgroup if it has the CAP_SYS_NICE capability set. This version of the patch adds a 'allow_attach' handler instead of reusing the 'can_attach' handler. If the 'can_attach' handler is reused, a new cgroup that implements 'can_attach' but not the permission checks could end up with no permission checks at all. Change-Id: Icfa950aa9321d1ceba362061d32dc7dfa2c64f0c Original-Author: San Mehat <san@google.com> Signed-off-by: Colin Cross <ccross@android.com>
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63351df85f7ece011618955054c1b0d15b393691 |
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26-Jan-2015 |
Ruchi Kandoi <kandoiruchi@google.com> |
Fix compile errors in accordance with changes from 3.14 to 3.18 Signed-off-by: Ruchi Kandoi<kandoiruchi@google.com>
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16474253cb671233c662ad89a88fee802dc36e15 |
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07-Nov-2014 |
Rom Lemarchand <romlem@android.com> |
cgroup: refactor allow_attach function into common code move cpu_cgroup_allow_attach to a common subsys_cgroup_allow_attach. This allows any process with CAP_SYS_NICE to move tasks across cgroups if they use this function as their allow_attach handler. Bug: 18260435 Change-Id: I6bb4933d07e889d0dc39e33b4e71320c34a2c90f Signed-off-by: Rom Lemarchand <romlem@android.com>
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e756c7b698604f11a979f2781d06eb7b80aba363 |
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25-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
Revert "cgroup: remove redundant variable in cgroup_mount()" This reverts commit 0c7bf3e8cab7900e17ce7f97104c39927d835469. If there are child cgroups in the cgroupfs and then we umount it, the superblock will be destroyed but the cgroup_root will be kept around. When we mount it again, cgroup_mount() will find this cgroup_root and allocate a new sb for it. So with this commit we will be trapped in a dead loop in the case described above, because kernfs_pin_sb() keeps returning NULL. Currently I don't see how we can avoid using both pinned_sb and new_sb, so just revert it. Cc: Al Viro <viro@ZenIV.linux.org.uk> Reported-by: Andrey Wagin <avagin@gmail.com> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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2aad2a86f6685c10360ec8a5a55eb9ab7059cb72 |
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24-Sep-2014 |
Tejun Heo <tj@kernel.org> |
percpu_ref: add PERCPU_REF_INIT_* flags With the recent addition of percpu_ref_reinit(), percpu_ref now can be used as a persistent switch which can be turned on and off repeatedly where turning off maps to killing the ref and waiting for it to drain; however, there currently isn't a way to initialize a percpu_ref in its off (killed and drained) state, which can be inconvenient for certain persistent switch use cases. Similarly, percpu_ref_switch_to_atomic/percpu() allow dynamic selection of operation mode; however, currently a newly initialized percpu_ref is always in percpu mode making it impossible to avoid the latency overhead of switching to atomic mode. This patch adds @flags to percpu_ref_init() and implements the following flags. * PERCPU_REF_INIT_ATOMIC : start ref in atomic mode * PERCPU_REF_INIT_DEAD : start ref killed and drained These flags should be able to serve the above two use cases. v2: target_core_tpg.c conversion was missing. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Kent Overstreet <kmo@daterainc.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <hannes@cmpxchg.org>
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0c7bf3e8cab7900e17ce7f97104c39927d835469 |
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20-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: remove redundant variable in cgroup_mount() Both pinned_sb and new_sb indicate if a new superblock is needed, so we can just remove new_sb. Note now we must check if kernfs_tryget_sb() returns NULL, because when it returns NULL, kernfs_mount() may still re-use an existing superblock, which is just allocated by another concurent mount. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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3e2cd91ab92665148616a80dc0745c499d2746a7 |
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20-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: fix missing unlock in cgroup_release_agent() The patch 971ff4935538: "cgroup: use a per-cgroup work for release agent" from Sep 18, 2014, leads to the following static checker warning: kernel/cgroup.c:5310 cgroup_release_agent() warn: 'mutex:&cgroup_mutex' is sometimes locked here and sometimes unlocked. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a25eb52e81a40e986179a790fbb5a1f02f482b7a |
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19-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: remove CGRP_RELEASABLE flag We call put_css_set() after setting CGRP_RELEASABLE flag in cgroup_task_migrate(), but in other places we call it without setting the flag. I don't see the necessity of this flag. Moreover once the flag is set, it will never be cleared, unless writing to the notify_on_release control file, so it can be quite confusing if we look at the output of debug.releasable. # mount -t cgroup -o debug xxx /cgroup # mkdir /cgroup/child # cat /cgroup/child/debug.releasable 0 <-- shows 0 though the cgroup is empty # echo $$ > /cgroup/child/tasks # cat /cgroup/child/debug.releasable 0 # echo $$ > /cgroup/tasks && echo $$ > /cgroup/child/tasks # cat /proc/child/debug.releasable 1 <-- shows 1 though the cgroup is not empty This patch removes the flag, and now debug.releasable shows if the cgroup is empty or not. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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006f4ac49742b5f70ef7e39176fd42a500144ccc |
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18-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: simplify proc_cgroup_show() Use the ONE macro instead of REG, and we can simplify proc_cgroup_show(). Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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971ff49355387fef41d1327434d8939721a4eb35 |
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18-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: use a per-cgroup work for release agent Instead of using a global work to schedule release agent on removable cgroups, we change to use a per-cgroup work to do this, which makes the code much simpler. v2: use a dedicated work instead of reusing css->destroy_work. (Tejun) Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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eb4aec84d6bdf98d00cedb41c18000f7a31e648a |
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18-Sep-2014 |
Zefan Li <lizefan@huawei.com> |
cgroup: fix unbalanced locking cgroup_pidlist_start() holds cgrp->pidlist_mutex and then calls pidlist_array_load(), and cgroup_pidlist_stop() releases the mutex. It is wrong that we release the mutex in the failure path in pidlist_array_load(), because cgroup_pidlist_stop() will be called no matter if cgroup_pidlist_start() returns errno or not. Fixes: 4bac00d16a8760eae7205e41d2c246477d42a210 Cc: <stable@vger.kernel.org> # 3.14+ Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
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0c8fc2c1210556434835adfb2274f41704853e8a |
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17-Sep-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove bogus comments We never grab cgroup mutex in fork and exit paths no matter whether notify_on_release is set or not. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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244bb9a6336d2aa53526261ec35c593ebd5c1a33 |
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17-Sep-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove redundant code in cgroup_rmdir() We no longer clear kn->priv in cgroup_rmdir(), so we don't need to get an extra refcnt. Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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6213daab2547fdc0d02a86abf3ac209ac6881ae3 |
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17-Sep-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove some useless forward declarations Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a34375ef9e65340a138fc0be287de5c940d260fc |
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08-Sep-2014 |
Tejun Heo <tj@kernel.org> |
percpu-refcount: add @gfp to percpu_ref_init() Percpu allocator now supports allocation mask. Add @gfp to percpu_ref_init() so that !GFP_KERNEL allocation masks can be used with percpu_refs too. This patch doesn't make any functional difference. v2: blk-mq conversion was missing. Updated. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <koverstreet@google.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Cc: Jens Axboe <axboe@kernel.dk>
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aa32362f011c6e863132b16c1761487166a4bad2 |
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04-Sep-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: check cgroup liveliness before unbreaking kernfs When cgroup_kn_lock_live() is called through some kernfs operation and another thread is calling cgroup_rmdir(), we'll trigger the warning in cgroup_get(). ------------[ cut here ]------------ WARNING: CPU: 1 PID: 1228 at kernel/cgroup.c:1034 cgroup_get+0x89/0xa0() ... Call Trace: [<c16ee73d>] dump_stack+0x41/0x52 [<c10468ef>] warn_slowpath_common+0x7f/0xa0 [<c104692d>] warn_slowpath_null+0x1d/0x20 [<c10bb999>] cgroup_get+0x89/0xa0 [<c10bbe58>] cgroup_kn_lock_live+0x28/0x70 [<c10be3c1>] __cgroup_procs_write.isra.26+0x51/0x230 [<c10be5b2>] cgroup_tasks_write+0x12/0x20 [<c10bb7b0>] cgroup_file_write+0x40/0x130 [<c11aee71>] kernfs_fop_write+0xd1/0x160 [<c1148e58>] vfs_write+0x98/0x1e0 [<c114934d>] SyS_write+0x4d/0xa0 [<c16f656b>] sysenter_do_call+0x12/0x12 ---[ end trace 6f2e0c38c2108a74 ]--- Fix this by calling css_tryget() instead of cgroup_get(). v2: - move cgroup_tryget() right below cgroup_get() definition. (Tejun) Cc: <stable@vger.kernel.org> # 3.15+ Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a4189487da1b4f8260c6006b9dc47c3c4107a5ae |
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04-Sep-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: delay the clearing of cgrp->kn->priv Run these two scripts concurrently: for ((; ;)) { mkdir /cgroup/sub rmdir /cgroup/sub } for ((; ;)) { echo $$ > /cgroup/sub/cgroup.procs echo $$ > /cgroup/cgroup.procs } A kernel bug will be triggered: BUG: unable to handle kernel NULL pointer dereference at 00000038 IP: [<c10bbd69>] cgroup_put+0x9/0x80 ... Call Trace: [<c10bbe19>] cgroup_kn_unlock+0x39/0x50 [<c10bbe91>] cgroup_kn_lock_live+0x61/0x70 [<c10be3c1>] __cgroup_procs_write.isra.26+0x51/0x230 [<c10be5b2>] cgroup_tasks_write+0x12/0x20 [<c10bb7b0>] cgroup_file_write+0x40/0x130 [<c11aee71>] kernfs_fop_write+0xd1/0x160 [<c1148e58>] vfs_write+0x98/0x1e0 [<c114934d>] SyS_write+0x4d/0xa0 [<c16f656b>] sysenter_do_call+0x12/0x12 We clear cgrp->kn->priv in the end of cgroup_rmdir(), but another concurrent thread can access kn->priv after the clearing. We should move the clearing to css_release_work_fn(). At that time no one is holding reference to the cgroup and no one can gain a new reference to access it. v2: - move RCU_INIT_POINTER() into the else block. (Tejun) - remove the cgroup_parent() check. (Tejun) - update the comment in css_tryget_online_from_dir(). Cc: <stable@vger.kernel.org> # 3.15+ Reported-by: Toralf Förster <toralf.foerster@gmx.de> Signed-off-by: Zefan Li <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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251f8c0364f99fc21fcc7b07e4ec6b4f3250d841 |
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25-Aug-2014 |
Dongsheng Yang <yangds.fnst@cn.fujitsu.com> |
cgroup: fix a typo in comment. There is no function named cgroup_enable_task_cg_links(). Instead, the correct function name in this comment should be cgroup_enabled_task_cg_lists(). Signed-off-by: Dongsheng Yang <yangds.fnst@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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fa8137be6ba632041e725e4623258ba27a2cf9be |
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08-Aug-2014 |
Vivek Goyal <vgoyal@redhat.com> |
cgroup: Display legacy cgroup files on default hierarchy Kernel command line parameter cgroup__DEVEL__legacy_files_on_dfl forces legacy cgroup files to show up on default hierarhcy if susbsystem does not have any files defined for default hierarchy. But this seems to be working only if legacy files are defined in ss->legacy_cftypes. If one adds some cftypes later using cgroup_add_legacy_cftypes(), these files don't show up on default hierarchy. Update the function accordingly so that the dynamically added legacy files also show up in the default hierarchy if the target subsystem is also using the base legacy files for the default hierarchy. tj: Patch description and comment updates. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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71b1fb5c4473a5b1e601d41b109bdfe001ec82e0 |
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18-Aug-2014 |
Alban Crequy <alban.crequy@collabora.co.uk> |
cgroup: reject cgroup names with '\n' /proc/<pid>/cgroup contains one cgroup path on each line. If cgroup names are allowed to contain "\n", applications cannot parse /proc/<pid>/cgroup safely. Signed-off-by: Alban Crequy <alban.crequy@collabora.co.uk> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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5de4fa13c4df302db41e80ca679df24fdad0d661 |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: initialize cgrp_dfl_root_inhibit_ss_mask from !->dfl_files test cgrp_dfl_root_inhibit_ss_mask determines which subsystems are not supported on the default hierarchy and is currently initialized statically and just includes the debug subsystem. Now that there's cgroup_subsys->dfl_files, we can easily tell which subsystems support the default hierarchy or not. Let's initialize cgrp_dfl_root_inhibit_ss_mask by testing whether cgroup_subsys->dfl_files is NULL. After all, subsystems with NULL ->dfl_files aren't useable on the default hierarchy anyway. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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05ebb6e60f044a9cef2549b6204559276500f363 |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make CFTYPE_ONLY_ON_DFL and CFTYPE_NO_ internal to cgroup core cgroup now distinguishes cftypes for the default and legacy hierarchies more explicitly by using separate arrays and CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE should be and are used only inside cgroup core proper. Let's make it clear that the flags are internal by prefixing them with double underscores. CFTYPE_INSANE is renamed to __CFTYPE_NOT_ON_DFL for consistency. The two flags are also collected and assigned bits >= 16 so that they aren't mixed with the published flags. v2: Convert the extra ones in cgroup_exit_cftypes() which are added by revision to the previous patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a8ddc8215e1a4cd9dc5d6210811cfc381a489ec2 |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: distinguish the default and legacy hierarchies when handling cftypes Until now, cftype arrays carried files for both the default and legacy hierarchies and the files which needed to be used on only one of them were flagged with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE. This gets confusing very quickly and we may end up exposing interface files to the default hierarchy without thinking it through. This patch makes cgroup core provide separate sets of interfaces for cftype handling so that the cftypes for the default and legacy hierarchies are clearly distinguished. The previous two patches renamed the existing ones so that they clearly indicate that they're for the legacy hierarchies. This patch adds the interface for the default hierarchy and apply them selectively depending on the hierarchy type. * cftypes added through cgroup_subsys->dfl_cftypes and cgroup_add_dfl_cftypes() only show up on the default hierarchy. * cftypes added through cgroup_subsys->legacy_cftypes and cgroup_add_legacy_cftypes() only show up on the legacy hierarchies. * cgroup_subsys->dfl_cftypes and ->legacy_cftypes can point to the same array for the cases where the interface files are identical on both types of hierarchies. * This makes all the existing subsystem interface files legacy-only by default and all subsystems will have no interface file created when enabled on the default hierarchy. Each subsystem should explicitly review and compose the interface for the default hierarchy. * A boot param "cgroup__DEVEL__legacy_files_on_dfl" is added which makes subsystems which haven't decided the interface files for the default hierarchy to present the legacy files on the default hierarchy so that its behavior on the default hierarchy can be tested. As the awkward name suggests, this is for development only. * memcg's CFTYPE_INSANE on "use_hierarchy" is noop now as the whole array isn't used on the default hierarchy. The flag is removed. v2: Updated documentation for cgroup__DEVEL__legacy_files_on_dfl. v3: Clear CFTYPE_ONLY_ON_DFL and CFTYPE_INSANE when cfts are removed as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Aristeu Rozanski <aris@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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2cf669a58dc08fa065a8bd0dca866c0e6cb358cc |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: replace cgroup_add_cftypes() with cgroup_add_legacy_cftypes() Currently, cftypes added by cgroup_add_cftypes() are used for both the unified default hierarchy and legacy ones and subsystems can mark each file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to appear only on one of them. This is quite hairy and error-prone. Also, we may end up exposing interface files to the default hierarchy without thinking it through. cgroup_subsys will grow two separate cftype addition functions and apply each only on the hierarchies of the matching type. This will allow organizing cftypes in a lot clearer way and encourage subsystems to scrutinize the interface which is being exposed in the new default hierarchy. In preparation, this patch adds cgroup_add_legacy_cftypes() which currently is a simple wrapper around cgroup_add_cftypes() and replaces all cgroup_add_cftypes() usages with it. While at it, this patch drops a completely spurious return from __hugetlb_cgroup_file_init(). This patch doesn't introduce any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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5577964e64692e17cc498854b7e0833e6532cd64 |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_subsys->base_cftypes to ->legacy_cftypes Currently, cgroup_subsys->base_cftypes is used for both the unified default hierarchy and legacy ones and subsystems can mark each file with either CFTYPE_ONLY_ON_DFL or CFTYPE_INSANE if it has to appear only on one of them. This is quite hairy and error-prone. Also, we may end up exposing interface files to the default hierarchy without thinking it through. cgroup_subsys will grow two separate cftype arrays and apply each only on the hierarchies of the matching type. This will allow organizing cftypes in a lot clearer way and encourage subsystems to scrutinize the interface which is being exposed in the new default hierarchy. In preparation, this patch renames cgroup_subsys->base_cftypes to cgroup_subsys->legacy_cftypes. This patch is pure rename. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Aristeu Rozanski <aris@redhat.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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a14c6874be09a05a48093df8df87ca021f310332 |
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15-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: split cgroup_base_files[] into cgroup_{dfl|legacy}_base_files[] Currently cgroup_base_files[] contains the cgroup core interface files for both legacy and default hierarchies with each file tagged with CFTYPE_INSANE and CFTYPE_ONLY_ON_DFL. This is difficult to read. Let's separate it out to two separate tables, cgroup_dfl_base_files[] and cgroup_legacy_base_files[], and use the appropriate one in cgroup_mkdir() depending on the hierarchy type. This makes tagging each file unnecessary. This patch doesn't introduce any behavior changes. v2: cgroup_dfl_base_files[] was missing the termination entry triggering WARN in cgroup_init_cftypes() for 0day kernel testing robot. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Jet Chen <jet.chen@intel.com>
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7b9a6ba56e9519ed5413a002dc0b0f01aa598bb5 |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: clean up sane_behavior handling After the previous patch to remove sane_behavior support from non-default hierarchies, CGRP_ROOT_SANE_BEHAVIOR is used only to indicate the default hierarchy while parsing mount options. This patch makes the following cleanups around it. * Don't show it in the mount option. Eventually the default hierarchy will be assigned a different filesystem type. * As sane_behavior is no longer effective on non-default hierarchies and the default hierarchy doesn't accept any mount options, parse_cgroupfs_options() can consider sane_behavior mount option as indicating the default hierarchy and fail if any other options are specified with it. While at it, remove one of the double blank lines in the function. * cgroup_mount() can now simply test CGRP_ROOT_SANE_BEHAVIOR to tell whether to mount the default hierarchy or not. * As CGROUP_ROOT_SANE_BEHAVIOR's only role now is indicating whether to select the default hierarchy or not during mount, it doesn't need to be set in the default hierarchy itself. cgroup_init_early() updated accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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aa6ec29bee8692ce232132f1a1ea2a1f9196610e |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove sane_behavior support on non-default hierarchies sane_behavior has been used as a development vehicle for the default unified hierarchy. Now that the default hierarchy is in place, the flag became redundant and confusing as its usage is allowed on all hierarchies. There are gonna be either the default hierarchy or legacy ones. Let's make that clear by removing sane_behavior support on non-default hierarchies. This patch replaces cgroup_sane_behavior() with cgroup_on_dfl(). The comment on top of CGRP_ROOT_SANE_BEHAVIOR is moved to on top of cgroup_on_dfl() with sane_behavior specific part dropped. On the default and legacy hierarchies w/o sane_behavior, this shouldn't cause any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz>
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c1d5d42efdb3e0470c1cfd2fcb50bc3eae813283 |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make interface file "cgroup.sane_behavior" legacy-only "cgroup.sane_behavior" is added to help distinguishing whether sane_behavior is in effect or not. We now have the default hierarchy where the flag is always in effect and are planning to remove supporting sane behavior on the legacy hierarchies making this file on the default hierarchy rather pointless. Let's make it legacy only and thus always zero. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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7450e90bbb8d834c190cc8100d1cc41888358c7c |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove CGRP_ROOT_OPTION_MASK cgroup_root->flags only contains CGRP_ROOT_* flags and there's no reason to mask the flags. Remove CGRP_ROOT_OPTION_MASK. This doesn't cause any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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af0ba6789c8e43518635606d0af1ff475ba7471a |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_subsys->depends_on Currently, the blkio subsystem attributes all of writeback IOs to the root. One of the issues is that there's no way to tell who originated a writeback IO from block layer. Those IOs are usually issued asynchronously from a task which didn't have anything to do with actually generating the dirty pages. The memory subsystem, when enabled, already keeps track of the ownership of each dirty page and it's desirable for blkio to piggyback instead of adding its own per-page tag. blkio piggybacking on memory is an implementation detail which preferably should be handled automatically without requiring explicit userland action. To achieve that, this patch implements cgroup_subsys->depends_on which contains the mask of subsystems which should be enabled together when the subsystem is enabled. The previous patches already implemented the support for enabled but invisible subsystems and cgroup_subsys->depends_on can be easily implemented by updating cgroup_refresh_child_subsys_mask() so that it calculates cgroup->child_subsys_mask considering cgroup_subsys->depends_on of the explicitly enabled subsystems. Documentation/cgroups/unified-hierarchy.txt is updated to explain that subsystems may not become immediately available after being unused from userland and that dependency could be a factor in it. As subsystems may already keep residual references, this doesn't significantly change how subsystem rebinding can be used. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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b4536f0cab2b18414e26101a2b9d484c5cbea0c0 |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_subsys->css_reset() cgroup is implementing support for subsystem dependency which would require a way to enable a subsystem even when it's not directly configured through "cgroup.subtree_control". The previous patches added support for explicitly and implicitly enabled subsystems and showing/hiding their interface files. An explicitly enabled subsystem may become implicitly enabled if it's turned off through "cgroup.subtree_control" but there are subsystems depending on it. In such cases, the subsystem, as it's turned off when seen from userland, shouldn't enforce any resource control. Also, the subsystem may be explicitly turned on later again and its interface files should be as close to the intial state as possible. This patch adds cgroup_subsys->css_reset() which is invoked when a css is hidden. The callback should disable resource control and reset the state to the vanilla state. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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f63070d350e3562baa6196f1043e01cd8da2509a |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make interface files visible iff enabled on cgroup->subtree_control cgroup is implementing support for subsystem dependency which would require a way to enable a subsystem even when it's not directly configured through "cgroup.subtree_control". The preceding patch distinguished cgroup->subtree_control and ->child_subsys_mask where the former is the subsystems explicitly configured by the userland and the latter is all enabled subsystems currently is equal to the former but will include subsystems implicitly enabled through dependency. Subsystems which are enabled due to dependency shouldn't be visible to userland. This patch updates cgroup_subtree_control_write() and create_css() such that interface files are not created for implicitly enabled subsytems. * @visible paramter is added to create_css(). Interface files are created only when true. * If an already implicitly enabled subsystem is turned on through "cgroup.subtree_control", the existing css should be used. css draining is skipped. * cgroup_subtree_control_write() computes the new target cgroup->child_subsys_mask and create/kill or show/hide csses accordingly. As the two subsystem masks are still kept identical, this patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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667c24917144e34880f821486bf0a6e4d05a3a14 |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce cgroup->subtree_control cgroup is implementing support for subsystem dependency which would require a way to enable a subsystem even when it's not directly configured through "cgroup.subtree_control". Previously, cgroup->child_subsys_mask directly reflected "cgroup.subtree_control" and the enabled subsystems in the child cgroups. This patch adds cgroup->subtree_control which "cgroup.subtree_control" operates on. cgroup->child_subsys_mask is now calculated from cgroup->subtree_control by cgroup_refresh_child_subsys_mask(), which sets it identical to cgroup->subtree_control for now. This will allow using cgroup->child_subsys_mask for all the enabled subsystems including the implicit ones and ->subtree_control for tracking the explicitly requested ones. This patch keeps the two masks identical and doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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c29adf24e0c443fb4433efb6a62bd91fdb739c34 |
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09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: reorganize cgroup_subtree_control_write() Make the following two reorganizations to cgroup_subtree_control_write(). These are to prepare for future changes and shouldn't cause any functional difference. * Move availability above css offlining wait. * Move cgrp->child_subsys_mask update above new css creation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
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3a32bd72d77058d768dbb38183ad517f720dd1bc |
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30-Jun-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix a race between cgroup_mount() and cgroup_kill_sb() We've converted cgroup to kernfs so cgroup won't be intertwined with vfs objects and locking, but there are dark areas. Run two instances of this script concurrently: for ((; ;)) { mount -t cgroup -o cpuacct xxx /cgroup umount /cgroup } After a while, I saw two mount processes were stuck at retrying, because they were waiting for a subsystem to become free, but the root associated with this subsystem never got freed. This can happen, if thread A is in the process of killing superblock but hasn't called percpu_ref_kill(), and at this time thread B is mounting the same cgroup root and finds the root in the root list and performs percpu_ref_try_get(). To fix this, we try to increase both the refcnt of the superblock and the percpu refcnt of cgroup root. v2: - we should try to get both the superblock refcnt and cgroup_root refcnt, because cgroup_root may have no superblock assosiated with it. - adjust/add comments. tj: Updated comments. Renamed @sb to @pinned_sb. Cc: <stable@vger.kernel.org> # 3.15 Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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970317aa48c6ef66cd023c039c2650c897bad927 |
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30-Jun-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix mount failure in a corner case # cat test.sh #! /bin/bash mount -t cgroup -o cpu xxx /cgroup umount /cgroup mount -t cgroup -o cpu,cpuacct xxx /cgroup umount /cgroup # ./test.sh mount: xxx already mounted or /cgroup busy mount: according to mtab, xxx is already mounted on /cgroup It's because the cgroupfs_root of the first mount was under destruction asynchronously. Fix this by delaying and then retrying mount for this case. v3: - put the refcnt immediately after getting it. (Tejun) v2: - use percpu_ref_tryget_live() rather that introducing percpu_ref_alive(). (Tejun) - adjust comment. tj: Updated the comment a bit. Cc: <stable@vger.kernel.org> # 3.15 Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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9a1049da9bd2cd83fe11d46433e603c193aa9c71 |
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28-Jun-2014 |
Tejun Heo <tj@kernel.org> |
percpu-refcount: require percpu_ref to be exited explicitly Currently, a percpu_ref undoes percpu_ref_init() automatically by freeing the allocated percpu area when the percpu_ref is killed. While seemingly convenient, this has the following niggles. * It's impossible to re-init a released reference counter without going through re-allocation. * In the similar vein, it's impossible to initialize a percpu_ref count with static percpu variables. * We need and have an explicit destructor anyway for failure paths - percpu_ref_cancel_init(). This patch removes the automatic percpu counter freeing in percpu_ref_kill_rcu() and repurposes percpu_ref_cancel_init() into a generic destructor now named percpu_ref_exit(). percpu_ref_destroy() is considered but it gets confusing with percpu_ref_kill() while "exit" clearly indicates that it's the counterpart of percpu_ref_init(). All percpu_ref_cancel_init() users are updated to invoke percpu_ref_exit() instead and explicit percpu_ref_exit() calls are added to the destruction path of all percpu_ref users. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Benjamin LaHaise <bcrl@kvack.org> Cc: Kent Overstreet <kmo@daterainc.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Nicholas A. Bellinger <nab@linux-iscsi.org> Cc: Li Zefan <lizefan@huawei.com>
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99bae5f94185c2cc65701e95c54e31e2f4345b88 |
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12-Jun-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix broken css_has_online_children() After running: # mount -t cgroup cpu xxx /cgroup && mkdir /cgroup/sub && \ rmdir /cgroup/sub && umount /cgroup I found the cgroup root still existed: # cat /proc/cgroups #subsys_name hierarchy num_cgroups enabled cpuset 0 1 1 cpu 1 1 1 ... It turned out css_has_online_children() is broken. Signed-off-by: Li Zefan <lizefan@huawei.com> Sigend-off-by: Tejun Heo <tj@kernel.org>
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c731ae1d0f02a300697a8b1564780ad28a6c2013 |
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05-Jun-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: disallow disabled controllers on the default hierarchy After booting with cgroup_disable=memory, I still saw memcg files in the default hierarchy, and I can write to them, though it won't take effect. # dmesg ... Disabling memory control group subsystem ... # mount -t cgroup -o __DEVEL__sane_behavior xxx /cgroup # ls /cgroup ... memory.failcnt memory.move_charge_at_immigrate memory.force_empty memory.numa_stat memory.limit_in_bytes memory.oom_control ... # cat /cgroup/memory.usage_in_bytes 0 tj: Minor comment update. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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1f779fb28aa07350d72976d304591d216ca86f0e |
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04-Jun-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: don't destroy the default root The default root is allocated and initialized at boot phase, so we shouldn't destroy the default root when it's umounted, otherwise it will lead to disaster. Just try mount and then umount the default root, and the kernel will crash immediately. v2: - No need to check for CSS_NO_REF in cgroup_get/put(). (Tejun) - Better call cgroup_put() for the default root in kill_sb(). (Tejun) - Add a comment. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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c9482a5bdcc09be9096f40e858c5fe39c389cd52 |
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26-Apr-2014 |
Jianyu Zhan <nasa4836@gmail.com> |
kernfs: move the last knowledge of sysfs out from kernfs There is still one residue of sysfs remaining: the sb_magic SYSFS_MAGIC. However this should be kernfs user specific, so this patch moves it out. Kerrnfs user should specify their magic number while mouting. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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26fc9cd200ec839e0b3095e05ae018f27314e7aa |
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26-Apr-2014 |
Jianyu Zhan <nasa4836@gmail.com> |
kernfs: move the last knowledge of sysfs out from kernfs There is still one residue of sysfs remaining: the sb_magic SYSFS_MAGIC. However this should be kernfs user specific, so this patch moves it out. Kerrnfs user should specify their magic number while mouting. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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5533e0114425dcdb878f11b291f2727af8667a7c |
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15-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: disallow debug controller on the default hierarchy The debug controller, as its name suggests, exposes cgroup core internals to userland to aid debugging. Unfortunately, except for the name, there's no provision to prevent its usage in production configurations and the controller is widely enabled and mounted leaking internal details to userland. Like most other debug information, the information exposed by debug isn't interesting even for debugging itself once the related parts are working reliably. This controller has no reason for existing. This patch implements cgrp_dfl_root_inhibit_ss_mask which can suppress specific subsystems on the default hierarchy and adds the debug subsystem to it so that it can be gradually deprecated as usages move towards the unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org>
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f3d4650015301d1c880df4523f7e7ef320a38aab |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: convert cgroup_has_live_children() into css_has_online_children() Now that cgroup liveliness and css onliness are the same state, convert cgroup_has_live_children() into css_has_online_children() so that it can be used for actual csses too. The function now uses css_for_each_child() for iteration and is published. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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184faf32328c65c9d86b19577b8d8b90bdd2cd2e |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use CSS_ONLINE instead of CGRP_DEAD Use CSS_ONLINE on the self css to indicate whether a cgroup has been killed instead of CGRP_DEAD. This will allow re-using css online test for cgroup liveliness test. This doesn't introduce any functional change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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c2931b70a32c705b9bd5762f5044f9eac8a52bb3 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: iterate cgroup_subsys_states directly Currently, css_next_child() is implemented as finding the next child cgroup which has the css enabled, which used to be the only way to do it as only cgroups participated in sibling lists and thus could be iteratd. This works as long as what's required during iteration is not missing online csses; however, it turns out that there are use cases where offlined but not yet released csses need to be iterated. This is difficult to implement through cgroup iteration the unified hierarchy as there may be multiple dying csses for the same subsystem associated with single cgroup. After the recent changes, the cgroup self and regular csses behave identically in how they're linked and unlinked from the sibling lists including assertion of CSS_RELEASED and css_next_child() can simply switch to iterating csses directly. This both simplifies the logic and ensures that all visible non-released csses are included in the iteration whether there are multiple dying csses for a subsystem or not. As all other iterators depend on css_next_child() for sibling iteration, this changes behaviors of all css iterators. Add and update explanations on the css states which are included in traversal to all iterators. As css iteration could always contain offlined csses, this shouldn't break any of the current users and new usages which need iteration of all on and offline csses can make use of the new semantics. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
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de3f034182ecbf0efbcef7ab8b253c6c3049a592 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce CSS_RELEASED and reduce css iteration fallback window css iterations allow the caller to drop RCU read lock. As long as the caller keeps the current position accessible, it can simply re-grab RCU read lock later and continue iteration. This is achieved by using CGRP_DEAD to detect whether the current positions next pointer is safe to dereference and if not re-iterate from the beginning to the next position using ->serial_nr. CGRP_DEAD is used as the marker to invalidate the next pointer and the only requirement is that the marker is set before the next sibling starts its RCU grace period. Because CGRP_DEAD is set at the end of cgroup_destroy_locked() but the cgroup is unlinked when the reference count reaches zero, we currently have a rather large window where this fallback re-iteration logic can be triggered. This patch introduces CSS_RELEASED which is set when a css is unlinked from its sibling list. This still keeps the re-iteration logic working while drastically reducing the window of its activation. While at it, rewrite the comment in css_next_child() to reflect the new flag and better explain the synchronization. This will also enable iterating csses directly instead of through cgroups. v2: CSS_RELEASED now assigned to 1 << 2 as 1 << 0 is used by CSS_NO_REF. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0cb51d71c1fa9234afe4213089844be76ec1765a |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup->serial_nr into cgroup_subsys_state We're moving towards using cgroup_subsys_states as the fundamental structural blocks. All csses including the cgroup->self and actual ones now form trees through css->children and ->sibling which follow the same rules as what cgroup->children and ->sibling followed. This patch moves cgroup->serial_nr which is used to implement css iteration into css. Note that all csses, regardless of their types, allocate their serial numbers from the same monotonically increasing counter. This doesn't affect the ordering needed by css iteration or cause any other material behavior changes. This will be used to update css iteration. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1fed1b2e36ba1aa0257004a97e75bbdb70f216b5 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: link all cgroup_subsys_states in their sibling lists Currently, while all csses have ->children and ->sibling, only the self csses of cgroups make use of them. This patch makes all other csses to link themselves on the sibling lists too. This will be used to update css iteration. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d5c419b68e368fdd9f1857bf8d4bb4480edb9b80 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup->sibling and ->children into cgroup_subsys_state We're moving towards using cgroup_subsys_states as the fundamental structural blocks. Let's move cgroup->sibling and ->children into cgroup_subsys_state. This is pure move without functional change and only cgroup->self's fields are actually used. Other csses will make use of the fields later. While at it, update init_and_link_css() so that it zeroes the whole css before initializing it and remove explicit zeroing of ->flags. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d51f39b05ce0008118c45945e681b20484990571 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup->parent cgroup->parent is redundant as cgroup->self.parent can also be used to determine the parent cgroup and we're moving towards using cgroup_subsys_states as the fundamental structural blocks. This patch introduces cgroup_parent() which follows cgroup->self.parent and removes cgroup->parent. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5c9d535b893f30266ea29fe377cb9b002fcd76aa |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove css_parent() cgroup in general is moving towards using cgroup_subsys_state as the fundamental structural component and css_parent() was introduced to convert from using cgroup->parent to css->parent. It was quite some time ago and we're moving forward with making css more prominent. This patch drops the trivial wrapper css_parent() and let the users dereference css->parent. While at it, explicitly mark fields of css which are public and immutable. v2: New usage from device_cgroup.c converted. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: "David S. Miller" <davem@davemloft.net> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Johannes Weiner <hannes@cmpxchg.org>
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3b514d24e200fcdcde0a57c354a51d3677a86743 |
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16-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: skip refcnting on normal root csses and cgrp_dfl_root self css 9395a4500404 ("cgroup: enable refcnting for root csses") enabled reference counting for root csses (cgroup_subsys_states) so that cgroup's self csses can be used to manage the lifetime of the containing cgroups. Unfortunately, this change was incorrect. During early init, cgrp_dfl_root self css refcnt is used. percpu_ref can't initialized during early init and its initialization is deferred till cgroup_init() time. This means that cpu was using percpu_ref which wasn't properly initialized. Due to the way percpu variables are laid out on x86, this didn't blow up immediately on x86 but ended up incrementing and decrementing the percpu variable at offset zero, whatever it may be; however, on other archs, this caused fault and early boot failure. As cgroup self csses for root cgroups of non-dfl hierarchies need working refcounting, we can't revert 9395a4500404. This patch adds CSS_NO_REF which explicitly inhibits reference counting on the css and sets it on all normal (non-self) csses and cgroup_dfl_root self css. v2: cgrp_dfl_root.self is the offending one. Set the flag on it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Warren <swarren@nvidia.com> Tested-by: Stephen Warren <swarren@nvidia.com> Fixes: 9395a4500404 ("cgroup: enable refcnting for root csses")
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9d755d33f0db8c9b49438f71b38a56e375b34360 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use cgroup->self.refcnt for cgroup refcnting Currently cgroup implements refcnting separately using atomic_t cgroup->refcnt. The destruction paths of cgroup and css are rather complex and bear a lot of similiarities including the use of RCU and bouncing to a work item. This patch makes cgroup use the refcnt of self css for refcnting instead of using its own. This makes cgroup refcnting use css's percpu refcnt and share the destruction mechanism. * css_release_work_fn() and css_free_work_fn() are updated to handle both csses and cgroups. This is a bit messy but should do until we can make cgroup->self a full css, which currently can't be done thanks to multiple hierarchies. * cgroup_destroy_locked() now performs percpu_ref_kill(&cgrp->self.refcnt) instead of cgroup_put(cgrp). * Negative refcnt sanity check in cgroup_get() is no longer necessary as percpu_ref already handles it. * Similarly, as a cgroup which hasn't been killed will never be released regardless of its refcnt value and percpu_ref has sanity check on kill, cgroup_is_dead() sanity check in cgroup_put() is no longer necessary. * As whether a refcnt reached zero or not can only be decided after the reference count is killed, cgroup_root->cgrp's refcnting can no longer be used to decide whether to kill the root or not. Let's make cgroup_kill_sb() explicitly initiate destruction if the root doesn't have any children. This makes sense anyway as unmounted cgroup hierarchy without any children should be destroyed. While this is a bit messy, this will allow pushing more bookkeeping towards cgroup->self and thus handling cgroups and csses in more uniform way. In the very long term, it should be possible to introduce a base subsystem and convert the self css to a proper one making things whole lot simpler and unified. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9395a4500404e05173eda9a2d198b6fa500e90c5 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: enable refcnting for root csses Currently, css_get(), css_tryget() and css_tryget_online() are noops for root csses as an optimization; however, we're planning to use css refcnts to track of cgroup lifetime too and root cgroups also need to be reference counted. Since css has been converted to percpu_refcnt, the overhead of refcnting is miniscule and this optimization isn't too meaningful anymore. Furthermore, controllers which optimize the root cgroup often never even invoke these functions in their hot paths. This patch enables refcnting for root csses too. This makes CSS_ROOT flag unused and removes it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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25e15d835036a70a53dcc993beaa036f8919a373 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: bounce css release through css->destroy_work css release is planned to do more and would require process context. Bounce it through css->destroy_work. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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249f3468a282dcbad53484c821bebb447f14ee03 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_destory_css_killed() cgroup_destroy_css_killed() is cgroup destruction stage which happens after all csses are offlined. After the recent updates, it no longer does anything other than putting the base reference. This patch removes the function and makes cgroup_destroy_locked() put the base ref at the end isntead. This also makes cgroup->nr_css unnecessary. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4e4e28472365f8c7a7c55f6b5706f68bc40c5b13 |
|
14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup->sibling unlinking to cgroup_put() Move cgroup->sibling unlinking from cgroup_destroy_css_killed() to cgroup_put(). This is later but still before the RCU grace period, so it doesn't break css_next_child() although there now is a larger window in which a dead cgroup is visible during css iteration. As css iteration always could have included offline csses, this doesn't affect correctness; however, it does make css_next_child() fall back to reiterting mode more often. This also makes cgroup_put() directly take cgroup_mutex, which limits where it can be called from. These are not immediately problematic and will be dealt with later. This change enables simplification of cgroup destruction path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9e4173e1f24fa3bd562f13b92ee34c7dfb1db7c9 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move check_for_release(parent) call to the end of cgroup_destroy_locked() Currently, check_for_release() on the parent of a destroyed cgroup is invoked from cgroup_destroy_css_killed(). This is because this is where the destroyed cgroup can be removed from the parent's children list. check_for_release() tests the emptiness of the list directly, so invoking it before removing the cgroup from the list makes it think that the parent still has children even when it no longer does. This patch updates check_for_release() to use cgroup_has_live_children() instead of directly testing ->children emptiness and moves check_for_release(parent) earlier to the end of cgroup_destroy_locked(). As cgroup_has_live_children() ignores cgroups marked DEAD, check_for_release() functions correctly as long as it's called after asserting DEAD. This makes release notification slightly more timely and more importantly enables further simplification of cgroup destruction path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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cbc125efada6d8c2555dd35e938694eb9b7cd791 |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: separate out cgroup_has_live_children() from cgroup_destroy_locked() We're expecting another user. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9d800df12d31734a6853915e9d2deb5d6747985f |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup->dummy_css to ->self and move it to the top cgroup->dummy_css is used as the placeholder css when performing css oriended operations on the cgroup. We're gonna shift more cgroup management to this css. Let's rename it to ->self and move it to the top. This is pure rename and field relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a015edd26e28afe225cdd04f25794bd2b3bbe2da |
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14-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use restart_syscall() for mount retries cgroup_mount() uses dumb delay-and-retry logic to wait for cgroup_root which is being destroyed. The retry currently loops inside cgroup_mount() proper. This patch makes it return with restart_syscall() instead so that retry travels out to userland boundary. This slightly simplifies the logic and more importantly makes the retry logic behave better when the wait for some reason becomes lengthy or infinite by allowing the operation to be suspended or terminated from userland. v2: The original patch forgot to free memory allocated for @opts. Fixed. Caught by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8353da1f91f12a3079ecc849226f371242d2807c |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_tree_mutex cgroup_tree_mutex was introduced to work around the circular dependency between cgroup_mutex and kernfs active protection - some kernfs file and directory operations needed cgroup_mutex putting cgroup_mutex under active protection but cgroup also needs to be able to access cgroup hierarchies and cftypes to determine which kernfs_nodes need to be removed. cgroup_tree_mutex nested above both cgroup_mutex and kernfs active protection and used to protect the hierarchy and cftypes. While this worked, it added a lot of double lockings and was generally cumbersome. kernfs provides a mechanism to opt out of active protection and cgroup was already using it for removal and subtree_control. There's no reason to mix both methods of avoiding circular locking dependency and the preceding cgroup_kn_lock_live() changes applied it to all relevant cgroup kernfs operations making it unnecessary to nest cgroup_mutex under kernfs active protection. The previous patch reversed the original lock ordering and put cgroup_mutex above kernfs active protection. After these changes, all cgroup_tree_mutex usages are now accompanied by cgroup_mutex making the former completely redundant. This patch removes cgroup_tree_mutex and all its usages. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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01f6474ce04fffd6282b569ac0a31f4b98d4c82a |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: nest kernfs active protection under cgroup_mutex After the recent cgroup_kn_lock_live() changes, cgroup_mutex is no longer nested below kernfs active protection. The two don't have any relationship now. This patch nests kernfs active protection under cgroup_mutex. All cftype operations now require both cgroup_tree_mutex and cgroup_mutex, temporary cgroup_mutex releases over kernfs operations are removed, and cgroup_add/rm_cftypes() grab both mutexes. This makes cgroup_tree_mutex redundant, which will be removed by the next patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e76ecaeef65c497153ceacf59c2e21c070d43f64 |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use cgroup_kn_lock_live() in other cgroup kernfs methods Make __cgroup_procs_write() and cgroup_release_agent_write() use cgroup_kn_lock_live() and cgroup_kn_unlock() instead of cgroup_lock_live_group(). This puts the operations under both cgroup_tree_mutex and cgroup_mutex protection without circular dependency from kernfs active protection. Also, this means that cgroup_mutex is no longer nested below kernfs active protection. There is no longer any place where the two locks interact. This leaves cgroup_lock_live_group() without any user. Removed. This will help simplifying cgroup locking. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a9746d8da786bc79b3b4ae1baa0fbbc4b795c1b7 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: factor out cgroup_kn_lock_live() and cgroup_kn_unlock() cgroup_mkdir(), cgroup_rmdir() and cgroup_subtree_control_write() share the logic to break active protection so that they can grab cgroup_tree_mutex which nests above active protection and/or remove self. Factor out this logic into cgroup_kn_lock_live() and cgroup_kn_unlock(). This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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cfc79d5bec04cdf26cd207d3e73d8bd59fd780a8 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup->kn->priv clearing to cgroup_rmdir() The ->priv field of a cgroup directory kernfs_node points back to the cgroup. This field is RCU cleared in cgroup_destroy_locked() for non-kernfs accesses from css_tryget_from_dir() and cgroupstats_build(). As these are only applicable to cgroups which finished creation successfully and fully initialized cgroups are always removed by cgroup_rmdir(), this can be safely moved to the end of cgroup_rmdir(). This will help simplifying cgroup locking and shouldn't introduce any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ddab2b6e0e516098efe6d3b69585bb25b1408d61 |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: grab cgroup_mutex earlier in cgroup_subtree_control_write() Move cgroup_lock_live_group() invocation upwards to right below cgroup_tree_mutex in cgroup_subtree_control_write(). This is to help the planned locking simplification. This doesn't make any userland-visible behavioral changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b3bfd983ca94cf1393accc11e90123c83909babb |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: collapse cgroup_create() into croup_mkdir() cgroup_mkdir() is the sole user of cgroup_create(). Let's collapse the latter into the former. This will help simplifying locking. While at it, remove now stale comment about inode locking. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ba0f4d761503bd9ce4c7458b56bfd7c3fdb51e86 |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: reorganize cgroup_create() Reorganize cgroup_create() so that all paths share unlock out path. * All err_* labels are renamed to out_* as they're now shared by both success and failure paths. * @err renamed to @ret for the similar reason as above and so that it's more consistent with other functions. * cgroup memory allocation moved after locking so that freeing failed cgroup happens before unlocking. While this moves more code inside critical section, memory allocations inside cgroup locking are already pretty common and this is unlikely to make any noticeable difference. * While at it, replace a stray @parent->root dereference with @root. This reorganization will help simplifying locking. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b7fc5ad235936379fae67a9f7b50bb53487a1a3a |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup->control_kn Now that cgroup_subtree_control_write() has access to the associated kernfs_open_file and thus the kernfs_node, there's no need to cache it in cgroup->control_kn on creation. Remove cgroup->control_kn and use @of->kn directly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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acbef755f40e204b8a6503fa79958d51a898762a |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: convert "tasks" and "cgroup.procs" handle to use cftype->write() cgroup_tasks_write() and cgroup_procs_write() are currently using cftype->write_u64(). This patch converts them to use cftype->write() instead. This allows access to the associated kernfs_open_file which will be necessary to implement the planned kernfs active protection manipulation for these files. This shifts buffer parsing to attach_task_by_pid() and makes it return @nbytes on success. Let's rename it to __cgroup_procs_write() to clearly indicate that this is a write handler implementation. This patch doesn't introduce any visible behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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6770c64e5c8da4705d1f0973bdeb5c2bf4f3a404 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: replace cftype->trigger() with cftype->write() cftype->trigger() is pointless. It's trivial to ignore the input buffer from a regular ->write() operation. Convert all ->trigger() users to ->write() and remove ->trigger(). This patch doesn't introduce any visible behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz>
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451af504df0c62f695a69b83c250486e77c66378 |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: replace cftype->write_string() with cftype->write() Convert all cftype->write_string() users to the new cftype->write() which maps directly to kernfs write operation and has full access to kernfs and cgroup contexts. The conversions are mostly mechanical. * @css and @cft are accessed using of_css() and of_cft() accessors respectively instead of being specified as arguments. * Should return @nbytes on success instead of 0. * @buf is not trimmed automatically. Trim if necessary. Note that blkcg and netprio don't need this as the parsers already handle whitespaces. cftype->write_string() has no user left after the conversions and removed. While at it, remove unnecessary local variable @p in cgroup_subtree_control_write() and stale comment about CGROUP_LOCAL_BUFFER_SIZE in cgroup_freezer.c. This patch doesn't introduce any visible behavior changes. v2: netprio was missing from conversion. Converted. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Aristeu Rozanski <arozansk@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: "David S. Miller" <davem@davemloft.net>
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b41686401e501430ffe93b575ef7959d2ecc6f2e |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cftype->write() During the recent conversion to kernfs, cftype's seq_file operations are updated so that they are directly mapped to kernfs operations and thus can fully access the associated kernfs and cgroup contexts; however, write path hasn't seen similar updates and none of the existing write operations has access to, for example, the associated kernfs_open_file. Let's introduce a new operation cftype->write() which maps directly to the kernfs write operation and has access to all the arguments and contexts. This will replace ->write_string() and ->trigger() and ease manipulation of kernfs active protection from cgroup file operations. Two accessors - of_cft() and of_css() - are introduced to enable accessing the associated cgroup context from cftype->write() which only takes kernfs_open_file for the context information. The accessors for seq_file operations - seq_cft() and seq_css() - are rewritten to wrap the of_ accessors. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ec903c0c858e4963a9e0724bdcadfa837253341c |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename css_tryget*() to css_tryget_online*() Unlike the more usual refcnting, what css_tryget() provides is the distinction between online and offline csses instead of protection against upping a refcnt which already reached zero. cgroup is planning to provide actual tryget which fails if the refcnt already reached zero. Let's rename the existing trygets so that they clearly indicate that they're onliness. I thought about keeping the existing names as-are and introducing new names for the planned actual tryget; however, given that each controller participates in the synchronization of the online state, it seems worthwhile to make it explicit that these functions are about on/offline state. Rename css_tryget() to css_tryget_online() and css_tryget_from_dir() to css_tryget_online_from_dir(). This is pure rename. v2: cgroup_freezer grew new usages of css_tryget(). Update accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
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46cfeb043b04f5878154bea36714709d46028495 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use release_agent_path_lock in cgroup_release_agent_show() release_path is now protected by release_agent_path_lock to allow accessing it without grabbing cgroup_mutex; however, cgroup_release_agent_show() was still grabbing cgroup_mutex. Let's convert it to release_agent_path_lock so that we don't have to worry about this one for the planned locking updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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7d331fa985d3a39d5b8cb60caf016d3e53e57c91 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use restart_syscall() for retries after offline waits in cgroup_subtree_control_write() After waiting for a child to finish offline, cgroup_subtree_control_write() jumps up to retry from after the input parsing and active protection breaking. This retry makes the scheduled locking update - removal of cgroup_tree_mutex - more difficult. Let's simplify it by returning with restart_syscall() for retries. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d37167ab7b3d67d53519585a44c47416e6758ed2 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update and fix parsing of "cgroup.subtree_control" I was confused that strsep() was equivalent to strtok_r() in skipping over consecutive delimiters. strsep() just splits at the first occurrence of one of the delimiters which makes the parsing very inflexible, which makes allowing multiple whitespace chars as delimters kinda moot. Let's just be consistently strict and require list of tokens separated by spaces. This is what Documentation/cgroups/unified-hierarchy.txt describes too. Also, parsing may access beyond the end of the string if the string ends with spaces or is zero-length. Make sure it skips zero-length tokens. Note that this also ensures that the parser doesn't puke on multiple consecutive spaces. v2: Add zero-length token skipping. v3: Added missing space after "==". Spotted by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0ab7a60dea71c285dfbb65e344d895b9c4f7bcb9 |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: css_release() shouldn't clear cgroup->subsys[] c1a71504e971 ("cgroup: don't recycle cgroup id until all csses' have been destroyed") made cgroup ID persist until a cgroup is released and add cgroup->subsys[] clearing to css_release() so that css_from_id() doesn't return a css which has already been released which happens before cgroup release; however, the right change here was updating offline_css() to clear cgroup->subsys[] which was done by e32978031016 ("cgroup: cgroup->subsys[] should be cleared after the css is offlined") instead of clearing it from css_release(). We're now clearing cgroup->subsys[] twice. This is okay for traditional hierarchies as a css's lifetime is the same as its cgroup's; however, this confuses unified hierarchy and turning on and off a controller repeatedly using "cgroup.subtree_control" can lead to an oops like the following which happens because cgroup->subsys[] is incorrectly cleared asynchronously by css_release(). BUG: unable to handle kernel NULL pointer dereference at 00000000000000 08 IP: [<ffffffff81130c11>] kill_css+0x21/0x1c0 PGD 1170d067 PUD f0ab067 PMD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU: 2 PID: 459 Comm: bash Not tainted 3.15.0-rc2-work+ #5 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff880009296710 ti: ffff88000e198000 task.ti: ffff88000e198000 RIP: 0010:[<ffffffff81130c11>] [<ffffffff81130c11>] kill_css+0x21/0x1c0 RSP: 0018:ffff88000e199dc8 EFLAGS: 00010202 RAX: 0000000000000001 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 0000000000000001 RSI: ffffffff8238a968 RDI: ffff880009296f98 RBP: ffff88000e199de0 R08: 0000000000000001 R09: 02b0000000000000 R10: 0000000000000000 R11: ffff880009296fc0 R12: 0000000000000001 R13: ffff88000db6fc58 R14: 0000000000000001 R15: ffff8800139dcc00 FS: 00007ff9160c5740(0000) GS:ffff88001fb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000013947000 CR4: 00000000000006e0 Stack: ffff88000e199de0 ffffffff82389160 0000000000000001 ffff88000e199e80 ffffffff8113537f 0000000000000007 ffff88000e74af00 ffff88000e199e48 ffff880009296710 ffff88000db6fc00 ffffffff8239c100 0000000000000002 Call Trace: [<ffffffff8113537f>] cgroup_subtree_control_write+0x85f/0xa00 [<ffffffff8112fd18>] cgroup_file_write+0x38/0x1d0 [<ffffffff8126fc97>] kernfs_fop_write+0xe7/0x170 [<ffffffff811f2ae6>] vfs_write+0xb6/0x1c0 [<ffffffff811f35ad>] SyS_write+0x4d/0xc0 [<ffffffff81d0acd2>] system_call_fastpath+0x16/0x1b Code: 5c 41 5d 41 5e 41 5f 5d c3 90 0f 1f 44 00 00 55 48 89 e5 41 54 53 48 89 fb 48 83 ec 08 8b 05 37 ad 29 01 85 c0 0f 85 df 00 00 00 <48> 8b 43 08 48 8b 3b be 01 00 00 00 8b 48 5c d3 e6 e8 49 ff ff RIP [<ffffffff81130c11>] kill_css+0x21/0x1c0 RSP <ffff88000e199dc8> CR2: 0000000000000008 ---[ end trace e7aae1f877c4e1b4 ]--- Remove the unnecessary cgroup->subsys[] clearing from css_release(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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54504e977ceee0bea6fbe8b632eceea771b18c6c |
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13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_idr_lock should be bh cgroup_idr_remove() can be invoked from bh leading to lockdep detecting possible AA deadlock (IN_BH/ON_BH). Make the lock bh-safe. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0cee8b7786467907e12d1d8f872e6dc73bc95204 |
|
13-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: fix offlining child waiting in cgroup_subtree_control_write() cgroup_subtree_control_write() waits for offline to complete child-by-child before enabling a controller; however, it has a couple bugs. * It doesn't initialize the wait_queue_t. This can lead to infinite hang on the following schedule() among other things. * It forgets to pin the child before releasing cgroup_tree_mutex and performing schedule(). The child may already be gone by the time it wakes up and invokes finish_wait(). Pin the child being waited on. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5024ae29cd285ce9e736776414da645d3a91828c |
|
08-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce task_css_is_root() Determining the css of a task usually requires RCU read lock as that's the only thing which keeps the returned css accessible till its reference is acquired; however, testing whether a task belongs to the root can be performed without dereferencing the returned css by comparing the returned pointer against the root one in init_css_set[] which never changes. Implement task_css_is_root() which can be invoked in any context. This will be used by the scheduled cgroup_freezer change. v2: cgroup no longer supports modular controllers. No need to export init_css_set. Pointed out by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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60106946ca7f63396680130b25511ccf6b7d5bff |
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05-May-2014 |
Fabian Frederick <fabf@skynet.be> |
kernel/cgroup.c: fix 2 kernel-doc warnings Fix typo and variable name. tj: Updated @cgrp argument description in cgroup_destroy_css_killed() Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Tejun Heo <tj@kernel.org>
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15a4c835e4ed3e60dd68727cd1907e3dd89563f4 |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup, memcg: implement css->id and convert css_from_id() to use it Until now, cgroup->id has been used to identify all the associated csses and css_from_id() takes cgroup ID and returns the matching css by looking up the cgroup and then dereferencing the css associated with it; however, now that the lifetimes of cgroup and css are separate, this is incorrect and breaks on the unified hierarchy when a controller is disabled and enabled back again before the previous instance is released. This patch adds css->id which is a subsystem-unique ID and converts css_from_id() to look up by the new css->id instead. memcg is the only user of css_from_id() and also converted to use css->id instead. For traditional hierarchies, this shouldn't make any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Li Zefan <lizefan@huawei.com>
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ddfcadab35dda6e5bc23ccf1c3055ecb63a71e49 |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update init_css() into init_and_link_css() init_css() takes the cgroup the new css belongs to as an argument and initializes the new css's ->cgroup and ->parent pointers but doesn't acquire the matching reference counts. After the previous patch, create_css() puts init_css() and reference acquisition right next to each other. Let's move reference acquistion into init_css() and rename the function to init_and_link_css(). This makes sense and is easier to follow. This makes the root csses to hold a reference on cgrp_dfl_root.cgrp, which is harmless. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a2bed8209a3afc3b2cf1c28383fb48155c1fea46 |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use RCU free in create_css() failure path Currently, when create_css() fails in the middle, the half-initialized css is freed by invoking cgroup_subsys->css_free() directly. This patch updates the function so that it invokes RCU free path instead. As the RCU free path puts the parent css and owning cgroup, their references are now acquired right after a new css is successfully allocated. This doesn't make any visible difference now but is to enable implementing css->id and RCU protected lookup by such IDs. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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6fa4918d03c39351aef3573ac3e7958d6a5ad9b6 |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: protect cgroup_root->cgroup_idr with a spinlock Currently, cgroup_root->cgroup_idr is protected by cgroup_mutex, which ends up requiring cgroup_put() to be invoked under sleepable context. This is okay for now but is an unusual requirement and we'll soon add css->id which will have the same problem but won't be able to simply grab cgroup_mutex as removal will have to happen from css_release() which can't sleep. Introduce cgroup_idr_lock and idr_alloc/replace/remove() wrappers which protects the idr operations with the lock and use them for cgroup_root->cgroup_idr. cgroup_put() no longer needs to grab cgroup_mutex and css_from_id() is updated to always require RCU read lock instead of either RCU read lock or cgroup_mutex, which doesn't affect the existing users. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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7d699ddb2b181a2c76e5ea18b1bdf102c4bebe4b |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup, memcg: allocate cgroup ID from 1 Currently, cgroup->id is allocated from 0, which is always assigned to the root cgroup; unfortunately, memcg wants to use ID 0 to indicate invalid IDs and ends up incrementing all IDs by one. It's reasonable to reserve 0 for special purposes. This patch updates cgroup core so that ID 0 is not used and the root cgroups get ID 1. The ID incrementing is removed form memcg. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Li Zefan <lizefan@huawei.com>
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69dfa00ccb72a37f3810687ca110e5a8154c6eed |
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04-May-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make flags and subsys_masks unsigned int There's no reason to use atomic bitops for cgroup_subsys_state->flags, cgroup_root->flags and various subsys_masks. This patch updates those to use bitwise and/or operations instead and converts them form unsigned long to unsigned int. This makes the fields occupy (marginally) smaller space and makes it clear that they don't require atomicity. This patch doesn't cause any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ed3d261b53f51c9505822d757d1800c79fb68788 |
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26-Apr-2014 |
Joe Perches <joe@perches.com> |
cgroup: Use more current logging style Use pr_fmt and remove embedded prefixes. Realign modified multi-line statements to open parenthesis. Convert embedded function name to "%s: ", __func__ Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a2a1f9eaf945c46b5b2bc0e439cba68888e3d540 |
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26-Apr-2014 |
Jianyu Zhan <nasa4836@gmail.com> |
cgroup: replace pr_warning with preferred pr_warn As suggested by scripts/checkpatch.pl, substitude all pr_warning() with pr_warn(). No functional change. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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f8719ccf7bc0858384c7e93d8c57fe69ae8c9eac |
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26-Apr-2014 |
Jianyu Zhan <nasa4836@gmail.com> |
cgroup: remove orphaned cgroup_pidlist_seq_operations 6612f05b88fa309c9 ("cgroup: unify pidlist and other file handling") has removed the only user of cgroup_pidlist_seq_operations : cgroup_pidlist_open(). This patch removes it. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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2f0edc04e702fc07d29621f9e361b9120a7594d0 |
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26-Apr-2014 |
Jianyu Zhan <nasa4836@gmail.com> |
cgroup: clean up obsolete comment for parse_cgroupfs_options() 1d5be6b287c8efc87 ("cgroup: move module ref handling into rebind_subsystems()") makes parse_cgroupfs_options() no longer takes refcounts on subsystems. And unified hierachy makes parse_cgroupfs_options not need to call with cgroup_mutex held to protect the cgroup_subsys[]. So this patch removes BUG_ON() and the comment. As the comment doesn't contain useful information afterwards, the whole comment is removed. Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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842b597ee0a7e1aa5a3148164ffdba00ec17f614 |
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26-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup.populated for the default hierarchy cgroup users often need a way to determine when a cgroup's subhierarchy becomes empty so that it can be cleaned up. cgroup currently provides release_agent for it; unfortunately, this mechanism is riddled with issues. * It delivers events by forking and execing a userland binary specified as the release_agent. This is a long deprecated method of notification delivery. It's extremely heavy, slow and cumbersome to integrate with larger infrastructure. * There is single monitoring point at the root. There's no way to delegate management of a subtree. * The event isn't recursive. It triggers when a cgroup doesn't have any tasks or child cgroups. Events for internal nodes trigger only after all children are removed. This again makes it impossible to delegate management of a subtree. * Events are filtered from the kernel side. "notify_on_release" file is used to subscribe to or suppress release event. This is unnecessarily complicated and probably done this way because event delivery itself was expensive. This patch implements interface file "cgroup.populated" which can be used to monitor whether the cgroup's subhierarchy has tasks in it or not. Its value is 0 if there is no task in the cgroup and its descendants; otherwise, 1, and kernfs_notify() notificaiton is triggers when the value changes, which can be monitored through poll and [di]notify. This is a lot ligther and simpler and trivially allows delegating management of subhierarchy - subhierarchy monitoring can block further propgation simply by putting itself or another process in the root of the subhierarchy and monitor events that it's interested in from there without interfering with monitoring higher in the tree. v2: Patch description updated as per Serge. v3: "cgroup.subtree_populated" renamed to "cgroup.populated". The subtree_ prefix was a bit confusing because "cgroup.subtree_control" uses it to denote the tree rooted at the cgroup sans the cgroup itself while the populated state includes the cgroup itself. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Lennart Poettering <lennart@poettering.net>
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f8f22e53a262ebee37fc98004f16b066cf5bc125 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement dynamic subtree controller enable/disable on the default hierarchy cgroup is switching away from multiple hierarchies and will use one unified default hierarchy where controllers can be dynamically enabled and disabled per subtree. The default hierarchy will serve as the unified hierarchy to which all controllers are attached and a css on the default hierarchy would need to also serve the tasks of descendant cgroups which don't have the controller enabled - ie. the tree may be collapsed from leaf towards root when viewed from specific controllers. This has been implemented through effective css in the previous patches. This patch finally implements dynamic subtree controller enable/disable on the default hierarchy via a new knob - "cgroup.subtree_control" which controls which controllers are enabled on the child cgroups. Let's assume a hierarchy like the following. root - A - B - C \ D root's "cgroup.subtree_control" determines which controllers are enabled on A. A's on B. B's on C and D. This coincides with the fact that controllers on the immediate sub-level are used to distribute the resources of the parent. In fact, it's natural to assume that resource control knobs of a child belong to its parent. Enabling a controller in "cgroup.subtree_control" declares that distribution of the respective resources of the cgroup will be controlled. Note that this means that controller enable states are shared among siblings. The default hierarchy has an extra restriction - only cgroups which don't contain any task may have controllers enabled in "cgroup.subtree_control". Combined with the other properties of the default hierarchy, this guarantees that, from the view point of controllers, tasks are only on the leaf cgroups. In other words, only leaf csses may contain tasks. This rules out situations where child cgroups compete against internal tasks of the parent, which is a competition between two different types of entities without any clear way to determine resource distribution between the two. Different controllers handle it differently and all the implemented behaviors are ambiguous, ad-hoc, cumbersome and/or just wrong. Having this structural constraints imposed from cgroup core removes the burden from controller implementations and enables showing one consistent behavior across all controllers. When a controller is enabled or disabled, css associations for the controller in the subtrees of each child should be updated. After enabling, the whole subtree of a child should point to the new css of the child. After disabling, the whole subtree of a child should point to the cgroup's css. This is implemented by first updating cgroup states such that cgroup_e_css() result points to the appropriate css and then invoking cgroup_update_dfl_csses() which migrates all tasks in the affected subtrees to the self cgroup on the default hierarchy. * When read, "cgroup.subtree_control" lists all the currently enabled controllers on the children of the cgroup. * White-space separated list of controller names prefixed with either '+' or '-' can be written to "cgroup.subtree_control". The ones prefixed with '+' are enabled on the controller and '-' disabled. * A controller can be enabled iff the parent's "cgroup.subtree_control" enables it and disabled iff no child's "cgroup.subtree_control" has it enabled. * If a cgroup has tasks, no controller can be enabled via "cgroup.subtree_control". Likewise, if "cgroup.subtree_control" has some controllers enabled, tasks can't be migrated into the cgroup. * All controllers which aren't bound on other hierarchies are automatically associated with the root cgroup of the default hierarchy. All the controllers which are bound to the default hierarchy are listed in the read-only file "cgroup.controllers" in the root directory. * "cgroup.controllers" in all non-root cgroups is read-only file whose content is equal to that of "cgroup.subtree_control" of the parent. This indicates which controllers can be used in the cgroup's "cgroup.subtree_control". This is still experimental and there are some holes, one of which is that ->can_attach() failure during cgroup_update_dfl_csses() may leave the cgroups in an undefined state. The issues will be addressed by future patches. v2: Non-root cgroups now also have "cgroup.controllers". Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f817de98513d060023be4fa1d061b29a6515273e |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: prepare migration path for unified hierarchy Unified hierarchy implementation would require re-migrating tasks onto the same cgroup on the default hierarchy to reflect updated effective csses. Update cgroup_migrate_prepare_dst() so that it accepts NULL as the destination cgrp. When NULL is specified, the destination is considered to be the cgroup on the default hierarchy associated with each css_set. After this change, the identity check in cgroup_migrate_add_src() isn't sufficient for noop detection as the associated csses may change without any cgroup association changing. The only way to tell whether a migration is noop or not is testing whether the source and destination csets are identical. The noop check in cgroup_migrate_add_src() is removed and cset identity test is added to cgroup_migreate_prepare_dst(). If it's detected that source and destination csets are identical, the cset is removed removed from @preloaded_csets and all the migration nodes are cleared which makes cgroup_migrate() ignore the cset. Also, make the function append the destination css_sets to @preloaded_list so that destination css_sets always come after source css_sets. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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7fd8c565d8a501486d63d7ee07fd6582e97db437 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update subsystem rebind restrictions Because the default root couldn't have any non-root csses attached to it, rebinding away from it was always allowed; however, the default hierarchy will soon host the unified hierarchy and have non-root csses so the rebind restrictions need to be updated accordingly. Instead of special casing rebinding from the default hierarchy and then checking whether the source hierarchy has children cgroups, which implies non-root csses for !dfl hierarchies, simply check whether the source hierarchy has non-root csses for the subsystem using css_next_child(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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6803c006282768ec850760766a6e4eb1a6ff87df |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: add css_set->dfl_cgrp To implement the unified hierarchy behavior, we'll need to be able to determine the associated cgroup on the default hierarchy from css_set. Let's add css_set->dfl_cgrp so that it can be accessed conveniently and efficiently. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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bd53d617b34c781dac8e22dbc75e8f182d918ecf |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: allow cgroup creation and suppress automatic css creation in the unified hierarchy Now that effective css handling has been added and iterators updated accordingly, it's safe to allow cgroup creation in the default hierarchy. Unblock cgroup creation in the default hierarchy. As the default hierarchy will implement explicit enabling and disabling of controllers on each cgroup, suppress automatic css enabling on cgroup creation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e32978031016f56be977a9a856ba4d9f447db51f |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup->subsys[] should be cleared after the css is offlined After a css finishes offlining, offline_css() mistakenly performs RCU_INIT_POINTER(css->cgroup->subsys[ss->id], css) which just sets the cgroup->subsys[] pointer to the current value. The intention was to clear it after offline is complete, not reassign the same value. Update it to assign NULL instead of the current value. This makes cgroup_css() to return NULL once offline is complete. All the existing users of the function either can handle NULL return already or guarantee that the css doesn't get offlined. While this is a bugfix, as css lifetime is currently tied to the cgroup it belongs to, this bug doesn't cause any actual problems. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3ebb2b6ef38875b866ec0118bfae7bc52afd0166 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: teach css_task_iter about effective csses Currently, css_task_iter iterates tasks associated with a css by visiting each css_set associated with the owning cgroup and walking tasks of each of them. This works fine for !unified hierarchies as each cgroup has its own css for each associated subsystem on the hierarchy; however, on the planned unified hierarchy, a cgroup may not have csses associated and its tasks would be considered associated with the matching css of the nearest ancestor which has the subsystem enabled. This means that on the default unified hierarchy, just walking all tasks associated with a cgroup isn't enough to walk all tasks which are associated with the specified css. If any of its children doesn't have the matching css enabled, task iteration should also include all tasks from the subtree. We already added cgroup->e_csets[] to list all css_sets effectively associated with a given css and walk css_sets on that list instead to achieve such iteration. This patch updates css_task_iter iteration such that it walks css_sets on cgroup->e_csets[] instead of cgroup->cset_links if iteration is requested on an non-dummy css. Thanks to the previous iteration update, this change can be achieved with the addition of css_task_iter->ss and minimal updates to css_advance_task_iter() and css_task_iter_start(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0f0a2b4fa6210147131082999f1f16d7fb79abf8 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: reorganize css_task_iter This patch reorganizes css_task_iter so that adding effective css support is easier. * s/->cset_link/->cset_pos/ and s/->task/->task_pos/ for consistency * ->origin_css is used to determine whether the iteration reached the last css_set. Replace it with explicit ->cset_head so that css_advance_task_iter() doesn't have to know the termination condition directly. * css_task_iter_next() currently assumes that it's walking list of cgrp_cset_link and reaches into the current cset through the current link to determine the termination conditions for task walking. As this won't always be true for effective css walking, add ->tasks_head and ->mg_tasks_head and use them to control task walking so that css_task_iter_next() doesn't have to know how css_sets are being walked. This patch doesn't make any behavior changes. The iteration logic stays unchanged after the patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3b281afbc3a06cd69c54e6db1a04a8e73997723f |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make css_next_child() skip missing csses css_next_child() walks the children of the specified css. It does this by finding the next cgroup and then returning the requested css. On the default unified hierarchy, a cgroup may not have a css associated with it even if the hierarchy has the subsystem enabled. This patch updates css_next_child() so that it skips children without the requested css associated. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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2d8f243a5e6efa57fb7c46fe83fafa45b33d0ec2 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup->e_csets[] On the default unified hierarchy, a cgroup may be associated with csses of its ancestors, which means that a css of a given cgroup may be associated with css_sets of descendant cgroups. This means that we can't walk all tasks associated with a css by iterating the css_sets associated with the cgroup as there are css_sets which are pointing to the css but linked on the descendants. This patch adds per-subsystem list heads cgroup->e_csets[]. Any css_set which is pointing to a css is linked to css->cgroup->e_csets[$SUBSYS_ID] through css_set->e_cset_node[$SUBSYS_ID]. The lists are protected by css_set_rwsem and will allow us to walk all css_sets associated with a given css so that we can find out all associated tasks. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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aec3dfcb2e43892180ee053e8c260dcdeccf4392 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce effective cgroup_subsys_state In the planned default unified hierarchy, controllers may get dynamically attached to and detached from a cgroup and a cgroup may not have csses for all the controllers associated with the hierarchy. When a cgroup doesn't have its own css for a given controller, the css of the nearest ancestor with the controller enabled will be used, which is called the effective css. This patch introduces cgroup_e_css() and for_each_e_css() to access the effective csses and convert compare_css_sets(), find_existing_css_set() and cgroup_migrate() to use the effective csses so that they can handle cgroups with partial csses correctly. This means that for two css_sets to be considered identical, they should have both matching csses and cgroups. compare_css_sets() already compares both, not for correctness but for optimization. As this now becomes a matter of correctness, update the comments accordingly. For all !default hierarchies, cgroup_e_css() always equals cgroup_css(), so this patch doesn't change behavior. While at it, fix incorrect locking comment for for_each_css(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f392e51cd6ae6f6ee5b9b6d611cdc282b4c1711e |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update cgroup->subsys_mask to ->child_subsys_mask and restore cgroup_root->subsys_mask 944196278d3d ("cgroup: move ->subsys_mask from cgroupfs_root to cgroup") moved ->subsys_mask from cgroup_root to cgroup to prepare for the unified hierarhcy; however, it turns out that carrying the subsys_mask of the children in the parent, instead of itself, is a lot more natural. This patch restores cgroup_root->subsys_mask and morphs cgroup->subsys_mask into cgroup->child_subsys_mask. * Uses of root->cgrp.subsys_mask are restored to root->subsys_mask. * Remove automatic setting and clearing of cgrp->subsys_mask and instead just inherit ->child_subsys_mask from the parent during cgroup creation. Note that this doesn't affect any current behaviors. * Undo __kill_css() separation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ea8fd3b47ff4ed4b1b5942bf3e0cb8d8f590ec59 |
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23-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_apply_cftypes() shouldn't skip the default hierarhcy cgroup_apply_cftypes() skip creating or removing files if the subsystem is attached to the default hierarchy, which led to missing files in the root of the default hierarchy. Skipping made sense when the default hierarchy was dummy; however, now that the default hierarchy is full functional and planned to be used as the unified hierarchy, it shouldn't be skipped over. Reported-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e37a06f10994c2ba86f54d8f96734f2483a869b8 |
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17-Apr-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix the retry path of cgroup_mount() If we hit the retry path, we'll call parse_cgroupfs_options() again, but the string we pass to it has been modified by the previous call to this function. This bug can be observed by: # mount -t cgroup -o name=foo,cpuset xxx /mnt && umount /mnt && \ mount -t cgroup -o name=foo,cpuset xxx /mnt mount: wrong fs type, bad option, bad superblock on xxx, missing codepage or helper program, or other error ... The second mount passed "name=foo,cpuset" to the parser, and then it hit the retry path and call the parser again, but this time the string passed to the parser is "name=foo". To fix this, we avoid calling parse_cgroupfs_options() again in this case. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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49957f8e2a43035a97d05bddefa394492a969c0d |
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07-Apr-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: newly created dirs and files should be owned by the creator While converting cgroup to kernfs, 2bd59d48ebfb ("cgroup: convert to kernfs") accidentally dropped the logic which makes newly created cgroup dirs and files owned by the current uid / gid. This broke cases where cgroup subtree management is delegated to !root as the sub manager wouldn't be able to create more than single level of hierarchy or put tasks into child cgroups it created. Among other things, this breaks user session management in systemd and one of the symptoms was 90s hang during shutdown. User session systemd running as the user creates a sub-service to initiate shutdown and tries to put kill(1) into it but fails because cgroup.procs is owned by root. This leads to 90s hang during shutdown. Implement cgroup_kn_set_ugid() which sets a kn's uid and gid to those of the caller and use it from file and dir creation paths. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
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c6b3d5bcd67c75961a1e8b9564d1475c0f194a84 |
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04-Apr-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix top cgroup refcnt leak As mount() and kill_sb() is not a one-to-one match, If we mount the same cgroupfs in serveral mount points, and then umount all of them, kill_sb() will be called only once. Try: # mount -t cgroup -o cpuacct xxx /cgroup # mount -t cgroup -o cpuacct xxx /cgroup2 # cat /proc/cgroups | grep cpuacct cpuacct 2 1 1 # umount /cgroup # umount /cgroup2 # cat /proc/cgroups | grep cpuacct cpuacct 2 1 1 You'll see cgroupfs will never be freed. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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1ec41830e087cda1f62dda4182c2b62811eb0ffc |
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28-Mar-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove useless argument from cgroup_exit() Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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e8604cb43690b781f9a7ad4a770f3e10259fe939 |
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28-Mar-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix spurious lockdep warning in cgroup_exit() cgroup_exit() is called in fork and exit path. If it's called in the failure path during fork, PF_EXITING isn't set, and then lockdep will complain. Fix this by removing cgroup_exit() in that failure path. cgroup_fork() does nothing that needs cleanup. Reported-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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01a971406177c2ca9834be6914a67e20f463a3e6 |
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23-Mar-2014 |
Monam Agarwal <monamagarwal123@gmail.com> |
cgroup: Use RCU_INIT_POINTER(x, NULL) in cgroup.c This patch replaces rcu_assign_pointer(x, NULL) with RCU_INIT_POINTER(x, NULL) The rcu_assign_pointer() ensures that the initialization of a structure is carried out before storing a pointer to that structure. And in the case of the NULL pointer, there is no structure to initialize. So, rcu_assign_pointer(p, NULL) can be safely converted to RCU_INIT_POINTER(p, NULL) Signed-off-by: Monam Agarwal <monamagarwal123@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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e1b2dc176f2d5be7952c47a4e4e8f3b06a90db1c |
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20-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: break kernfs active_ref protection in cgroup directory operations cgroup_tree_mutex should nest above the kernfs active_ref protection; however, cgroup_create() and cgroup_rename() were grabbing cgroup_tree_mutex while under kernfs active_ref protection. This has actualy possibility to lead to deadlocks in case these operations race against cgroup_rmdir() which invokes kernfs_remove() on directory kernfs_node while holding cgroup_tree_mutex. Neither cgroup_create() or cgroup_rename() requires active_ref protection. The former already has enough synchronization through cgroup_lock_live_group() and the latter doesn't care, so this can be fixed by updating both functions to break all active_ref protections before grabbing cgroup_tree_mutex. While this patch fixes the immediate issue, it probably needs further work in the long term - kernfs directories should enable lockdep annotations and maybe the better way to handle this is marking directory nodes as not needing active_ref protection rather than breaking it in each operation. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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1b9aba49eab5e85b0d3de8ba630cda6d68546297 |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_taskset walking order cgroup_taskset is used to track and iterate target tasks while migrating a task or process and should guarantee that the first task iterated is the task group leader if a process is being migrated. b3dc094e9390 ("cgroup: use css_set->mg_tasks to track target tasks during migration") replaced flex array cgroup_taskset->tc_array with css_set->mg_tasks list to remove process size limit and dynamic allocation during migration; unfortunately, it incorrectly used list operations which don't preserve order breaking the guarantee that cgroup_taskset_first() returns the leader for a process target. Fix it by using order preserving list operations. Note that as multiple src_csets may map to a single dst_cset, the iteration order may change across cgroup_task_migrate(); however, the leader is still guaranteed to be the first entry. The switch to list_splice_tail_init() at the end of cgroup_migrate() isn't strictly necessary. Let's still do it for consistency. Signed-off-by: Tejun Heo <tj@kernel.org>
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8cbbf2c972c4444cad36f61cd571714c39b8cf04 |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement CFTYPE_ONLY_ON_DFL This cftype flag makes the file only appear on the default hierarchy. This will later be used for cgroup.controllers file. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a2dd424750807f83632a2a70293961086fd8f870 |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgrp_dfl_root mountable cgrp_dfl_root will be used as the default unified hierarchy. This patch makes cgrp_dfl_root mountable by making the following changes. * cgroup_init_early() now initializes cgrp_dfl_root w/ CGRP_ROOT_SANE_BEHAVIOR. The default hierarchy is always sane. * parse_cgroupfs_options() and cgroup_mount() are updated such that cgrp_dfl_root is mounted if sane_behavior is specified w/o any subsystems. * rebind_subsystems() now populates the root directory of cgrp_dfl_root. Note that the function still guarantees success of rebinding subsystems to cgrp_dfl_root. If populating fails while rebinding to cgrp_dfl_root, it whines but ignores the error. * For backward compatibility, the default hierarchy shows up in /proc/$PID/cgroup only after it's explicitly mounted so that userland which doesn't make use of it doesn't see any change. * "current_css_set_cg_links" file of debug cgroup now treats the default hierarchy the same as other hierarchies. This is visible to userland. Given that it's for debug controller, this should be fine. * While at it, implement cgroup_on_dfl() which tests whether a give cgroup is on the default hierarchy or not. The above changes make cgrp_dfl_root mostly equivalent to other controllers but the actual unified hierarchy behaviors are not implemented yet. Let's plug child cgroup creation in cgrp_dfl_root from create_cgroup() for now. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4d3bb511b5f9980fc3e9ae5939ebc475b231d3fc |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: drop const from @buffer of cftype->write_string() cftype->write_string() just passes on the writeable buffer from kernfs and there's no reason to add const restriction on the buffer. The only thing const achieves is unnecessarily complicating parsing of the buffer. Drop const from @buffer. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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3dd06ffa9df99aa88f4e01eaa0c9d3cb362430b0 |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_dummy_root and related names The dummy root will be repurposed to serve as the default unified hierarchy. Let's rename things in preparation. * s/cgroup_dummy_root/cgrp_dfl_root/ * s/cgroupfs_root/cgroup_root/ as we don't do fs part directly anymore * s/cgroup_root->top_cgroup/cgroup_root->cgrp/ for brevity This is pure rename. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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944196278d3dea0cece1636de417b56897d9a108 |
|
19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move ->subsys_mask from cgroupfs_root to cgroup cgroupfs_root->subsys_mask represents the controllers attached to the hierarchy. This patch moves the field to cgroup. Subsystem initialization and rebinding updates the top cgroup's subsys_mask. For !root cgroups, the subsys_mask bits are set from create_css() and cleared from kill_css(), which effectively means that all cgroups will have the same subsys_mask as the top cgroup. While this doesn't make any difference now, this will help implementation of the default unified hierarchy where !root cgroups may have subsets of the top_cgroup's subsys_mask. While at it, __kill_css() is split out of kill_css(). The former doesn't care about the subsys_mask while the latter becomes noop if the controller is already killed and clears the matching bit if not before proceeding to killing the css. This will be used later by the default unified hierarchy implementation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5df3603229e520442502ff7fc5715c77bbf61912 |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: treat cgroup_dummy_root as an equivalent hierarchy during rebinding Currently, while rebinding, cgroup_dummy_root serves as the anchor point. In addition to the target root, rebind_subsystems() takes @added_mask and @removed_mask. The subsystems specified in the former are expected to be on the dummy root and then moved to the target root. The ones in the latter are moved from non-dummy root to dummy. Now that the dummy root is a fully functional one and we're planning to use it for the default unified hierarchy, this level of distinction between dummy and non-dummy roots is quite awkward. This patch updates rebind_subsystems() to take the target root and one subsystem mask and move the specified subsystmes to the target root which may or may not be the dummy root. IOW, unbinding now becomes moving the subsystems to the dummy root and binding to non-dummy root. This makes the dummy root mostly equivalent to other hierarchies in terms of the mechanism of moving subsystems around; however, we still retain all the semantical restrictions so that this patch doesn't introduce any visible behavior differences. Another noteworthy detail is that rebind_subsystems() guarantees that moving a subsystem to the dummy root never fails so that valid unmounting attempts always succeed. This unifies binding and unbinding of subsystems. The invocation points of ->bind() were inconsistent between the two and now moved after whole rebinding is complete. This doesn't break the current users and generally makes more sense. All rebind_subsystems() users are converted accordingly. Note that cgroup_remount() now makes two calls to rebind_subsystems() to bind and then unbind the requested subsystems. This will allow repurposing of the dummy hierarchy as the default unified hierarchy and shouldn't make any userland visible behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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985ed670144c25058f235276f69d687de1b7c7ba |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use cgroup_setup_root() to initialize cgroup_dummy_root cgroup_dummy_root is used to host controllers which aren't attached to any other hierarchy. The root is minimally set up during kernfs bootstrap and didn't go through full hierarchy initialization. We're planning to use cgroup_dummy_root for the default unified hierarchy and thus want it to be fully functional. Replace the special initialization, which was collected into cgroup_init() by the previous patch, with an invocation of cgroup_setup_root(). This simplifies the init path and makes cgroup_dummy_root a full hierarchy with its own kernfs_root and all. As this puts the dummy hierarchy on the cgroup_roots list, rename for_each_active_root() to for_each_root() and update its users to skip the dummy root for now. This patch doesn't cause any userland visible behavior changes at this point. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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172a2c0685ff3bc0b7a611b308aac0694de34594 |
|
19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: reorganize cgroup bootstrapping * Fields of init_css_set and css_set_count are now set using initializer instead of programmatically from cgroup_init_early(). * init_cgroup_root() now also takes @opts and performs the optional part of initialization too. The leftover part of cgroup_root_from_opts() is collapsed into its only caller - cgroup_mount(). * Initialization of cgroup_root_count and linking of init_css_set are moved from cgroup_init_early() to to cgroup_init(). None of the early_init users depends on init_css_set being linked. * Subsystem initializations are moved after dummy hierarchy init and init_css_set linking. These changes reorganize the bootstrap logic so that the dummy hierarchy can share the usual hierarchy init path and be made more normal. These changes don't make noticeable behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5d77381fd8aa631a8fda718c395da1319afb5d2d |
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19-Mar-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate setting of CGRP_DEAD In cgroup_destroy_locked(), move setting of CGRP_DEAD above invocations of kill_css(). This doesn't make any visible behavior difference now but will be used to inhibit manipulating controller enable states of a dying cgroup on the unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3eb59ec64fc7a3f4576da23f811b39331b830ba2 |
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18-Mar-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix a failure path in create_css() If online_css() fails, we should remove cgroup files belonging to css->ss. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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952aaa125428fae883670a2c2e40ea8044ca1eaa |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update cgroup_transfer_tasks() to either succeed or fail cgroup_transfer_tasks() can currently fail in the middle due to memory allocation failure. When that happens, the function just aborts and returns error code and there's no way to tell how many actually got migrated at the point of failure and or to revert the partial migration. Update it to use cgroup_migrate{_add_src|prepare_dst|migrate|finish}() so that the function either succeeds or fails as a whole as long as ->can_attach() doesn't fail. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0e1d768f1b1873272ec4e8dc1482bb5281855017 |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: drop task_lock() protection around task->cgroups For optimization, task_lock() is additionally used to protect task->cgroups. The optimization is pretty dubious as either css_set_rwsem is grabbed anyway or PF_EXITING already protects task->cgroups. It adds only overhead and confusion at this point. Let's drop task_[un]lock() and update comments accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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eaf797abc53b0ab3f0a02d4ef873a565fcce6daa |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update how a newly forked task gets associated with css_set When a new process is forked, cgroup_fork() associates it with the css_set of its parent but doesn't link it into it. After the new process is linked to tasklist, cgroup_post_fork() does the linking. This is problematic for cgroup_transfer_tasks() as there's no way to tell whether there are tasks which are pointing to a css_set but not linked yet. It is impossible to implement an operation which transfer all tasks of a cgroup to another and the current cgroup_transfer_tasks() can easily be tricked into leaving a newly forked process behind if it gets called between cgroup_fork() and cgroup_post_fork(). Let's make association with a css_set and linking atomic by moving it to cgroup_post_fork(). cgroup_fork() sets child->cgroups to init_css_set as a placeholder and cgroup_post_fork() is updated to perform both the association with the parent's cgroup and linking there. This means that a newly created task will point to init_css_set without holding a ref to it much like what it does on the exit path. Empty cg_list is used to indicate that the task isn't holding a ref to the associated css_set. This fixes an actual bug with cgroup_transfer_tasks(); however, I'm not marking it for -stable. The whole thing is broken in multiple other ways which require invasive updates to fix and I don't think it's worthwhile to bother with backporting this particular one. Fortunately, the only user is cpuset and these bugs don't crash the machine. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1958d2d53dadbb1c9aaf0b37741f13a60098b243 |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: split process / task migration into four steps Currently, process / task migration is a single operation which may fail depending on memory pressure or the involved controllers' ->can_attach() callbacks. One problem with this approach is migration of multiple targets. It's impossible to tell whether a given target will be successfully migrated beforehand and cgroup core can't keep track of enough states to roll back after intermediate failure. This is already an issue with cgroup_transfer_tasks(). Also, we're gonna need multiple target migration for unified hierarchy. This patch splits migration into four stages - cgroup_migrate_add_src(), cgroup_migrate_prepare_dst(), cgroup_migrate() and cgroup_migrate_finish(), where cgroup_migrate_prepare_dst() performs all the operations which may fail due to allocation failure without actually migrating the target. The four separate stages mean that, disregarding ->can_attach() failures, the success or failure of multi target migration can be determined before performing any actual migration. If preparations of all targets succeed, the whole thing will succeed. If not, the whole operation can fail without any side-effect. Since the previous patch to use css_set->mg_tasks to keep track of migration targets, the only thing which may need memory allocation during migration is the target css_sets. cgroup_migrate_prepare() pins all source and target css_sets and link them up. Note that this can be performed without holding threadgroup_lock even if the target is a process. As long as cgroup_mutex is held, no new css_set can be put into play. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ceb6a081f6f52d17ec9e46e271cc26a1eb8a7573 |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: separate out cset_group_from_root() from task_cgroup_from_root() This will be used by the planned migration path update. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b3dc094e93905ae9c1bc0815402ad8e5b203d068 |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: use css_set->mg_tasks to track target tasks during migration Currently, while migrating tasks from one cgroup to another, cgroup_attach_task() builds a flex array of all target tasks; unfortunately, this has a couple issues. * Flex array has size limit. On 64bit, struct task_and_cgroup is 24bytes making the flex element limit around 87k. It is a high number but not impossible to hit. This means that the current cgroup implementation can't migrate a process with more than 87k threads. * Process migration involves memory allocation whose size is dependent on the number of threads the process has. This means that cgroup core can't guarantee success or failure of multi-process migrations as memory allocation failure can happen in the middle. This is in part because cgroup can't grab threadgroup locks of multiple processes at the same time, so when there are multiple processes to migrate, it is imposible to tell how many tasks are to be migrated beforehand. Note that this already affects cgroup_transfer_tasks(). cgroup currently cannot guarantee atomic success or failure of the operation. It may fail in the middle and after such failure cgroup doesn't have enough information to roll back properly. It just aborts with some tasks migrated and others not. To resolve the situation, this patch updates the migration path to use task->cg_list to track target tasks. The previous patch already added css_set->mg_tasks and updated iterations in non-migration paths to include them during task migration. This patch updates migration path to actually make use of it. Instead of putting onto a flex_array, each target task is moved from its css_set->tasks list to css_set->mg_tasks and the migration path keeps trace of all the source css_sets and the associated cgroups. Once all source css_sets are determined, the destination css_set for each is determined, linked to the matching source css_set and put on a separate list. To iterate the target tasks, migration path just needs to iterat through either the source or target css_sets, depending on whether migration has been committed or not, and the tasks on their ->mg_tasks lists. cgroup_taskset is updated to contain the list_heads for source and target css_sets and the iteration cursor. cgroup_taskset_*() are accordingly updated to walk through css_sets and their ->mg_tasks. This resolves the above listed issues with moderate additional complexity. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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c75611282cf1bf717c1866e7a7eb4d0743815187 |
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25-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: add css_set->mg_tasks Currently, while migrating tasks from one cgroup to another, cgroup_attach_task() builds a flex array of all target tasks; unfortunately, this has a couple issues. * Flex array has size limit. On 64bit, struct task_and_cgroup is 24bytes making the flex element limit around 87k. It is a high number but not impossible to hit. This means that the current cgroup implementation can't migrate a process with more than 87k threads. * Process migration involves memory allocation whose size is dependent on the number of threads the process has. This means that cgroup core can't guarantee success or failure of multi-process migrations as memory allocation failure can happen in the middle. This is in part because cgroup can't grab threadgroup locks of multiple processes at the same time, so when there are multiple processes to migrate, it is imposible to tell how many tasks are to be migrated beforehand. Note that this already affects cgroup_transfer_tasks(). cgroup currently cannot guarantee atomic success or failure of the operation. It may fail in the middle and after such failure cgroup doesn't have enough information to roll back properly. It just aborts with some tasks migrated and others not. To resolve the situation, we're going to use task->cg_list during migration too. Instead of building a separate array, target tasks will be linked into a dedicated migration list_head on the owning css_set. Tasks on the migration list are treated the same as tasks on the usual tasks list; however, being on a separate list allows cgroup migration code path to keep track of the target tasks by simply keeping the list of css_sets with tasks being migrated, making unpredictable dynamic allocation unnecessary. In prepartion of such migration path update, this patch introduces css_set->mg_tasks list and updates css_set task iterations so that they walk both css_set->tasks and ->mg_tasks. Note that ->mg_tasks isn't used yet. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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532de3fc72adc2a6525c4d53c07bf81e1732083d |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update cgroup_enable_task_cg_lists() to grab siglock Currently, there's nothing preventing cgroup_enable_task_cg_lists() from missing set PF_EXITING and race against cgroup_exit(). Depending on the timing, cgroup_exit() may finish with the task still linked on css_set leading to list corruption. Fix it by grabbing siglock in cgroup_enable_task_cg_lists() so that PF_EXITING is guaranteed to be visible. This whole on-demand cg_list optimization is extremely fragile and has ample possibility to lead to bugs which can cause things like once-a-year oops during boot. I'm wondering whether the better approach would be just adding "cgroup_disable=all" handling which disables the whole cgroup rather than tempting fate with this on-demand craziness. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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dc5736ed7aaf942caaac0c15af74a018e04ec79d |
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17-Feb-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: add a validation check to cgroup_add_cftyps() Fengguang reported this bug: BUG: unable to handle kernel NULL pointer dereference at 0000003c IP: [<cc90b4ad>] cgroup_cfts_commit+0x27/0x1c1 ... Call Trace: [<cc9d1129>] ? kmem_cache_alloc_trace+0x33f/0x3b7 [<cc90c6fc>] cgroup_add_cftypes+0x8f/0xca [<cd78b646>] cgroup_init+0x6a/0x26a [<cd764d7d>] start_kernel+0x4d7/0x57a [<cd7642ef>] i386_start_kernel+0x92/0x96 This happens in a corner case. If CGROUP_SCHED=y but CFS_BANDWIDTH=n && FAIR_GROUP_SCHED=n && RT_GROUP_SCHED=n, we have: cpu_files[] = { { } /* terminate */ } When we pass cpu_files to cgroup_apply_cftypes(), as cpu_files[0].ss is NULL, we'll access NULL pointer. The bug was introduced by commit de00ffa56ea3132c6013fc8f07133b8a1014cf53 ("cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes()"). Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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6534fd6c15858fe4ce4ae568106225e68d5afa81 |
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14-Feb-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix memory leak in cgroup_mount() We should free the memory allocated in parse_cgroupfs_options() before calling this function again. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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bad34660344f37db8b55ce8bc139bddc7d83af1b |
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14-Feb-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix locking in cgroupstats_build() css_set_lock has been converted to css_set_rwsem, and rwsem can't nest inside rcu_read_lock. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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430af8ad9dad82d775d688155e1db1da385d3e7a |
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13-Feb-2014 |
Fengguang Wu <fengguang.wu@intel.com> |
cgroup: fix coccinelle warnings kernel/cgroup.c:2256:1-3: WARNING: PTR_RET can be used Use PTR_ERR_OR_ZERO rather than if(IS_ERR(...)) + PTR_ERR Generated by: coccinelle/api/ptr_ret.cocci Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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8541fecc04a91842f023cbfe2c376d4de3b5047e |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: unexport functions With module support gone, a lot of functions no longer need to be exported. Unexport them. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9db8de3722d184b8a431afd6bef803d6867ac889 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: cosmetic updates to cgroup_attach_task() cgroup_attach_task() is planned to go through restructuring. Let's tidy it up a bit in preparation. * Update cgroup_attach_task() to receive the target task argument in @leader instead of @tsk. * Rename @tsk to @task. * Rename @retval to @ret. This is purely cosmetic. v2: get_nr_threads() was using uninitialized @task instead of @leader. Fixed. Reported by Dan Carpenter. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Dan Carpenter <dan.carpenter@oracle.com>
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bc668c7519ff8b4681af80e92f463bec7bf7cf9e |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_taskset_cur_css() and cgroup_taskset_size() The two functions don't have any users left. Remove them along with cgroup_taskset->cur_cgrp. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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cb0f1fe9ba47c202a98a9d41ad5c12c0ac7732e9 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: move css_set_rwsem locking outside of cgroup_task_migrate() Instead of repeatedly locking and unlocking css_set_rwsem inside cgroup_task_migrate(), update cgroup_attach_task() to grab it outside of the loop and update cgroup_task_migrate() to use put_css_set_locked(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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89c5509b0d71d1609761bf72d33333ab206dac9f |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: separate out put_css_set_locked() and remove put_css_set_taskexit() put_css_set() is performed in two steps - it first tries to put without grabbing css_set_rwsem if such put wouldn't make the count zero. If that fails, it puts after write-locking css_set_rwsem. This patch separates out the second phase into put_css_set_locked() which should be called with css_set_rwsem locked. Also, put_css_set_taskexit() is droped and put_css_set() is made to take @taskexit. There are only a handful users of these functions. No point in providing different variants. put_css_locked() will be used by later changes. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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889ed9ceaa97bb02bf5d7349e24639f7fc5f4fa0 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove css_scan_tasks() css_scan_tasks() doesn't have any user left. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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96d365e0b86ee7ec6366c99669687e54c9f145e3 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make css_set_lock a rwsem and rename it to css_set_rwsem Currently there are two ways to walk tasks of a cgroup - css_task_iter_start/next/end() and css_scan_tasks(). The latter builds on the former but allows blocking while iterating. Unfortunately, the way css_scan_tasks() is implemented is rather nasty, it uses a priority heap of pointers to extract some number of tasks in task creation order and loops over them invoking the callback and repeats that until it reaches the end. It requires either preallocated heap or may fail under memory pressure, while unlikely to be problematic, the complexity is O(N^2), and in general just nasty. We're gonna convert all css_scan_users() to css_task_iter_start/next/end() and remove css_scan_users(). As css_scan_tasks() users may block, let's convert css_set_lock to a rwsem so that tasks can block during css_task_iter_*() is in progress. While this does increase the chance of possible deadlock scenarios, given the current usage, the probability is relatively low, and even if that happens, the right thing to do is updating the iteration in the similar way to css iterators so that it can handle blocking. Most conversions are trivial; however, task_cgroup_path() now expects to be called with css_set_rwsem locked instead of locking itself. This is because the function is called with RCU read lock held and rwsem locking should nest outside RCU read lock. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e406d1cfff6ab189c8676072d211809c94fecaf0 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: reimplement cgroup_transfer_tasks() without using css_scan_tasks() Reimplement cgroup_transfer_tasks() so that it repeatedly fetches the first task in the cgroup and then tranfers it. This achieves the same result without using css_scan_tasks() which is scheduled to be removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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07bc356ed2950048d33d667e933e1b913c6e6b6d |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_has_tasks() and unexport cgroup_task_count() cgroup_task_count() read-locks css_set_lock and walks all tasks to count them and then returns the result. The only thing all the users want is determining whether the cgroup is empty or not. This patch implements cgroup_has_tasks() which tests whether cgroup->cset_links is empty, replaces all cgroup_task_count() usages and unexports it. Note that the test isn't synchronized. This is the same as before. The test has always been racy. This will help planned css_set locking update. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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afeb0f9fd425239aa477c842480f240bfb6325b3 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate cgroup_enable_task_cg_lists() Move it above so that prototype isn't necessary. Let's also move the definition of use_task_css_set_links next to it. This is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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56fde9e01de45bcfabbb444d33e8bdd8388d2da0 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: enable task_cg_lists on the first cgroup mount Tasks are not linked on their css_sets until cgroup task iteration is actually used. This is to avoid incurring overhead on the fork and exit paths for systems which have cgroup compiled in but don't use it. This lazy binding also affects the task migration path. It has to be careful so that it doesn't link tasks to css_sets when task_cg_lists linking is not enabled yet. Unfortunately, this conditional linking in the migration path interferes with planned migration updates. This patch moves the lazy binding a bit earlier, to the first cgroup mount. It's a clear indication that cgroup is being used on the system and task_cg_lists linking is highly likely to be enabled soon anyway through "tasks" and "cgroup.procs" files. This allows cgroup_task_migrate() to always link @tsk->cg_list. Note that it may still race with cgroup_post_fork() but who wins that race is inconsequential. While at it, make use_task_css_set_links a bool, add sanity checks in cgroup_enable_task_cg_lists() and css_task_iter_start(), and update the former so that it's guaranteed and assumes to run only once. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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35585573055f37837eb752ee22eb5523682ca742 |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: drop CGRP_ROOT_SUBSYS_BOUND Before kernfs conversion, due to the way super_block lookup works, cgroup roots were created and made visible before being fully initialized. This in turn required a special flag to mark that the root hasn't been fully initialized so that the destruction path can tell fully bound ones from half initialized. That flag is CGRP_ROOT_SUBSYS_BOUND and no longer necessary after the kernfs conversion as the lookup and creation of new root are atomic w.r.t. cgroup_mutex. This patch removes the flag and passes the requests subsystem mask to cgroup_setup_root() so that it can set the respective mask bits as subsystems are bound. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d3ba07c3aa9ae3e03329b0a7f1a067c0647aa2af |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: disallow xattr, release_agent and name if sane_behavior Disallow more mount options if sane_behavior. Note that xattr used to generate warning. While at it, simplify option check in cgroup_mount() and update sane_behavior comment in cgroup.h. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1a11533fbd71792e8c5d36f6763fbce8df0d231d |
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13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
Revert "cgroup: use an ordered workqueue for cgroup destruction" This reverts commit ab3f5faa6255a0eb4f832675507d9e295ca7e9ba. Explanation from Hugh: It's because more thorough testing, by others here, found that it wasn't always solving the problem: so I asked Tejun privately to hold off from sending it in, until we'd worked out why not. Most of our testing being on a v3,11-based kernel, it was perfectly possible that the problem was merely our own e.g. missing Tejun's 8a2b75384444 ("workqueue: fix ordered workqueues in NUMA setups"). But that turned out not to be enough to fix it either. Then Filipe pointed out how percpu_ref_kill_and_confirm() uses call_rcu_sched() before we ever get to put the offline on to the workqueue: by the time we get to the workqueue, the ordering has already been lost. So, thanks for the Acks, but I'm afraid that this ordered workqueue solution is just not good enough: we should simply forget that patch and provide a different answer." Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com>
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776f02fa4e1ad70557c0318c70ce928e0642bee0 |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroupfs_root->refcnt Currently, cgroupfs_root and its ->top_cgroup are separated reference counted and the latter's is ignored. There's no reason to do this separately. This patch removes cgroupfs_root->refcnt and destroys cgroupfs_root when the top_cgroup is released. * cgroup_put() updated to ignore cgroup_is_dead() test for top cgroups. cgroup_free_fn() updated to handle root destruction when releasing a top cgroup. * As root destruction is now bounced through cgroup destruction, it is asynchronous. Update cgroup_mount() so that it waits for pending release which is currently implemented using msleep(). Converting this to proper wait_queue isn't hard but likely unnecessary. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3c9c825b8b50de7dbb015e6bfc04bb2da79364d9 |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroupfs_root->number_of_cgroups to ->nr_cgrps and make it atomic_t root->number_of_cgroups is currently an integer protected with cgroup_mutex. Except for sanity checks and proc reporting, the only place it's used is to check whether the root has any child during remount; however, this is a bit flawed as the counter is not decremented when the cgroup is unlinked but when it's released, meaning that there could be an extended period where all cgroups are removed but remount is still not allowed because some internal objects are lingering. While not perfect either, it'd be better to use emptiness test on root->top_cgroup.children. This patch updates cgroup_remount() to test top_cgroup's children instead, which makes number_of_cgroups only actual usage statistics printing in proc implemented in proc_cgroupstats_show(). Let's shorten its name and make it an atomic_t so that we don't have to worry about its synchronization. It's purely auxiliary at this point. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e61734c55c24cdf11b07e52a74aec4dc4a7f4bd0 |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup->name cgroup->name handling became quite complicated over time involving dedicated struct cgroup_name for RCU protection. Now that cgroup is on kernfs, we can drop all of it and simply use kernfs_name/path() and friends. Replace cgroup->name and all related code with kernfs name/path constructs. * Reimplement cgroup_name() and cgroup_path() as thin wrappers on top of kernfs counterparts, which involves semantic changes. pr_cont_cgroup_name() and pr_cont_cgroup_path() added. * cgroup->name handling dropped from cgroup_rename(). * All users of cgroup_name/path() updated to the new semantics. Users which were formatting the string just to printk them are converted to use pr_cont_cgroup_name/path() instead, which simplifies things quite a bit. As cgroup_name() no longer requires RCU read lock around it, RCU lockings which were protecting only cgroup_name() are removed. v2: Comment above oom_info_lock updated as suggested by Michal. v3: dummy_top doesn't have a kn associated and pr_cont_cgroup_name/path() ended up calling the matching kernfs functions with NULL kn leading to oops. Test for NULL kn and print "/" if so. This issue was reported by Fengguang Wu. v4: Rebased on top of 0ab02ca8f887 ("cgroup: protect modifications to cgroup_idr with cgroup_mutex"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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6f30558f37bfbd428e3854c2c34b5c32117c8f7e |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup hold onto its kernfs_node cgroup currently releases its kernfs_node when it gets removed. While not buggy, this makes cgroup->kn access rules complicated than necessary and leads to things like get/put protection around kernfs_remove() in cgroup_destroy_locked(). In addition, we want to use kernfs_name/path() and friends but also want to be able to determine a cgroup's name between removal and release. This patch makes cgroup hold onto its kernfs_node until freed so that cgroup->kn is always accessible. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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21a2d3430ba8c188af405a5c2eb9c06bdcb6add6 |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: simplify dynamic cftype addition and removal Dynamic cftype addition and removal using cgroup_add/rm_cftypes() respectively has been quite hairy due to vfs i_mutex. As i_mutex nests outside cgroup_mutex, cgroup_mutex has to be released and regrabbed on each iteration through the hierarchy complicating the process. Now that i_mutex is no longer in play, it can be simplified. * Just holding cgroup_tree_mutex is enough. No need to meddle with cgroup_mutex. * No reason to play the unlock - relock - check serial_nr dancing. Everything can be atomically while holding cgroup_tree_mutex. * cgroup_cfts_prepare() is replaced with direct locking of cgroup_tree_mutex. * cgroup_cfts_commit() no longer fiddles with locking. It just applies the cftypes change to the existing cgroups in the hierarchy. Renamed to cgroup_cfts_apply(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0adb070426dde2fd0b84e7f4f5cefcd8f0b24410 |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cftype_set cftype_set was added primarily to allow registering the same cftype array more than once for different subsystems. Nobody uses or needs such thing and it's already broken because each cftype has ->ss pointer which is initialized during registration. Let's add list_head ->node to cftype and use the first cftype entry in the array to link them instead of allocating separate cftype_set. While at it, trigger WARN if cft seems previously initialized during registration. This simplifies cftype handling a bit. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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80b13586997d8e584caa772bd99e2a3e55ac6abe |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate cgroup_rm_cftypes() cftype handling is about to be revamped. Relocate cgroup_rm_cftypes() above cgroup_add_cftypes() in preparation. This is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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86bf4b68759141459864ebd36ac3038a9cda895b |
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12-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: warn if "xattr" is specified with "sane_behavior" Mount option "xattr" is no longer necessary as it's enabled by default on kernfs. Warn if "xattr" is specified with "sane_behavior" so that the option can be removed in the future. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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2bd59d48ebfb3df41ee56938946ca0dd30887312 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: convert to kernfs cgroup filesystem code was derived from the original sysfs implementation which was heavily intertwined with vfs objects and locking with the goal of re-using the existing vfs infrastructure. That experiment turned out rather disastrous and sysfs switched, a long time ago, to distributed filesystem model where a separate representation is maintained which is queried by vfs. Unfortunately, cgroup stuck with the failed experiment all these years and accumulated even more problems over time. Locking and object lifetime management being entangled with vfs is probably the most egregious. vfs is never designed to be misused like this and cgroup ends up jumping through various convoluted dancing to make things work. Even then, operations across multiple cgroups can't be done safely as it'll deadlock with rename locking. Recently, kernfs is separated out from sysfs so that it can be used by users other than sysfs. This patch converts cgroup to use kernfs, which will bring the following benefits. * Separation from vfs internals. Locking and object lifetime management is contained in cgroup proper making things a lot simpler. This removes significant amount of locking convolutions, hairy object lifetime rules and the restriction on multi-cgroup operations. * Can drop a lot of code to implement filesystem interface as most are provided by kernfs. * Proper "severing" semantics, which allows controllers to not worry about lingering file accesses after offline. While the preceding patches did as much as possible to make the transition less painful, large part of the conversion has to be one discrete step making this patch rather large. The rest of the commit message lists notable changes in different areas. Overall ------- * vfs constructs replaced with kernfs ones. cgroup->dentry w/ ->kn, cgroupfs_root->sb w/ ->kf_root. * All dentry accessors are removed. Helpers to map from kernfs constructs are added. * All vfs plumbing around dentry, inode and bdi removed. * cgroup_mount() now directly looks for matching root and then proceeds to create a new one if not found. Synchronization and object lifetime ----------------------------------- * vfs inode locking removed. Among other things, this removes the need for the convolution in cgroup_cfts_commit(). Future patches will further simplify it. * vfs refcnting replaced with cgroup internal ones. cgroup->refcnt, cgroupfs_root->refcnt added. cgroup_put_root() now directly puts root->refcnt and when it reaches zero proceeds to destroy it thus merging cgroup_put_root() and the former cgroup_kill_sb(). Simliarly, cgroup_put() now directly schedules cgroup_free_rcu() when refcnt reaches zero. * Unlike before, kernfs objects don't hold onto cgroup objects. When cgroup destroys a kernfs node, all existing operations are drained and the association is broken immediately. The same for cgroupfs_roots and mounts. * All operations which come through kernfs guarantee that the associated cgroup is and stays valid for the duration of operation; however, there are two paths which need to find out the associated cgroup from dentry without going through kernfs - css_tryget_from_dir() and cgroupstats_build(). For these two, kernfs_node->priv is RCU managed so that they can dereference it under RCU read lock. File and directory handling --------------------------- * File and directory operations converted to kernfs_ops and kernfs_syscall_ops. * xattrs is implicitly supported by kernfs. No need to worry about it from cgroup. This means that "xattr" mount option is no longer necessary. A future patch will add a deprecated warning message when sane_behavior. * When cftype->max_write_len > PAGE_SIZE, it's necessary to make a private copy of one of the kernfs_ops to set its atomic_write_len. cftype->kf_ops is added and cgroup_init/exit_cftypes() are updated to handle it. * cftype->lockdep_key added so that kernfs lockdep annotation can be per cftype. * Inidividual file entries and open states are now managed by kernfs. No need to worry about them from cgroup. cfent, cgroup_open_file and their friends are removed. * kernfs_nodes are created deactivated and kernfs_activate() invocations added to places where creation of new nodes are committed. * cgroup_rmdir() uses kernfs_[un]break_active_protection() for self-removal. v2: - Li pointed out in an earlier patch that specifying "name=" during mount without subsystem specification should succeed if there's an existing hierarchy with a matching name although it should fail with -EINVAL if a new hierarchy should be created. Prior to the conversion, this used by handled by deferring failure from NULL return from cgroup_root_from_opts(), which was necessary because root was being created before checking for existing ones. Note that cgroup_root_from_opts() returned an ERR_PTR() value for error conditions which require immediate mount failure. As we now have separate search and creation steps, deferring failure from cgroup_root_from_opts() is no longer necessary. cgroup_root_from_opts() is updated to always return ERR_PTR() value on failure. - The logic to match existing roots is updated so that a mount attempt with a matching name but different subsys_mask are rejected. This was handled by a separate matching loop under the comment "Check for name clashes with existing mounts" but got lost during conversion. Merge the check into the main search loop. - Add __rcu __force casting in RCU_INIT_POINTER() in cgroup_destroy_locked() to avoid the sparse address space warning reported by kbuild test bot. Maybe we want an explicit interface to use kn->priv as RCU protected pointer? v3: Make CONFIG_CGROUPS select CONFIG_KERNFS. v4: Rebased on top of 0ab02ca8f887 ("cgroup: protect modifications to cgroup_idr with cgroup_mutex"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: kbuild test robot fengguang.wu@intel.com>
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f2e85d574e881ff3c597518c1ab48c86f9109880 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate functions in preparation of kernfs conversion Relocate cgroup_init/exit_root_id(), cgroup_free_root(), cgroup_kill_sb() and cgroup_file_name() in preparation of kernfs conversion. These are pure relocations to make kernfs conversion easier to follow. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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59f5296b51b86718dd6eecf0a268b2f1a1ec0a2d |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: misc preps for kernfs conversion * Un-inline seq_css(). After kernfs conversion, the function will need to dereference internal data structures. * Add cgroup_get/put_root() and replace direct super_block->s_active manipulatinos with them. These will be converted to kernfs_root refcnting. * Add cgroup_get/put() and replace dget/put() on cgrp->dentry with them. These will be converted to kernfs refcnting. * Update current_css_set_cg_links_read() to use cgroup_name() instead of reaching into the dentry name. The end result is the same. These changes don't make functional differences but will make transition to kernfs easier. v2: Rebased on top of 0ab02ca8f887 ("cgroup: protect modifications to cgroup_idr with cgroup_mutex"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b1664924062393bb048203bd4622e0b1c9e1d328 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce cgroup_ino() mm/memory-failure.c::hwpoison_filter_task() has been reaching into cgroup to extract the associated ino to be used as a filtering criterion. This is an implementation detail which shouldn't be depended upon from outside cgroup proper and is about to change with the scheduled kernfs conversion. This patch introduces a proper interface to determine the associated ino, cgroup_ino(), and updates hwpoison_filter_task() to use it instead of reaching directly into cgroup. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Wu Fengguang <fengguang.wu@intel.com>
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2da440a26ce4743bd3e71ba964ba3f983d09bba5 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce cgroup_init/exit_cftypes() Factor out cft->ss initialization into cgroup_init_cftypes() from cgroup_add_cftypes() and add cft->ss clearing to cgroup_rm_cftypes() through cgroup_exit_cftypes(). This doesn't make any meaningful difference now but the two new functions will be expanded during kernfs transition. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5f46990787e2721b4db190ddc8af6fdbe8f010d7 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update the meaning of cftype->max_write_len cftype->max_write_len is used to extend the maximum size of writes. It's interpreted in such a way that the actual maximum size is one less than the specified value. The default size is defined by CGROUP_LOCAL_BUFFER_SIZE. Its interpretation is quite confusing - its value is decremented by 1 and then compared for equality with max size, which means that the actual default size is CGROUP_LOCAL_BUFFER_SIZE - 2, which is 62 chars. There's no point in having a limit that low. Update its definition so that it means the actual string length sans termination and anything below PAGE_SIZE-1 is treated as PAGE_SIZE-1. .max_write_len for "release_agent" is updated to PATH_MAX-1 and cgroup_release_agent_write() is updated so that the redundant strlen() check is removed and it uses strlcpy() instead of strcpy(). .max_write_len initializations in blk-throttle.c and cfq-iosched.c are no longer necessary and removed. The one in cpuset is kept unchanged as it's an approximated value to begin with. This will also make transition to kernfs smoother. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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de00ffa56ea3132c6013fc8f07133b8a1014cf53 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_subsys->base_cftypes use cgroup_add_cftypes() Currently, cgroup_subsys->base_cftypes registration is different from dynamic cftypes registartion. Instead of going through cgroup_add_cftypes(), cgroup_init_subsys() invokes cgroup_init_cftsets() which makes use of cgroup_subsys->base_cftset which doesn't involve dynamic allocation. While avoiding dynamic allocation is somewhat nice, having two separate paths for cftypes registration is nasty, especially as we're planning to add more operations during cftypes registration. This patch drops cgroup_init_cftsets() and cgroup_subsys->base_cftset and registers base_cftypes using cgroup_add_cftypes(). This is done as a separate step in cgroup_init() instead of a part of cgroup_init_subsys(). This is because cgroup_init_subsys() can be called very early during boot when kmalloc() isn't available yet. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8d7e6fb0a1db970ac3589f87af0f2a20ef46654b |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update cgroup name handling Straightforward updates to cgroup name handling in preparation of kernfs conversion. * cgroup_alloc_name() is updated to take const char * isntead of dentry * for name source. * cgroup name formatting is separated out into cgroup_file_name(). While at it, buffer length protection is added. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d427dfeb120b92c0c5e2ca9d1ec6952de67ebad9 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: factor out cgroup_setup_root() from cgroup_mount() Factor out new root initialization into cgroup_setup_root() from cgroup_mount(). This makes it easier to follow and will ease kernfs conversion. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8e30e2b8ba0ee58aa0f442d0b4a3cac1a4f2efb5 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: restructure locking and error handling in cgroup_mount() cgroup is scheduled to be converted to kernfs. After conversion, cgroup_mount() won't use the sget() machinery for finding out existing super_blocks but instead would do that directly. It'll search the existing cgroupfs_roots for a matching one and create a new one iff a match doesn't exist. To ease such conversion, this patch restructures locking and error handling of the function. cgroup_tree_mutex and cgroup_mutex are grabbed from the get-go and held until return. For now, due to the way vfs locks nest outside cgroup mutexes, the two cgroup mutexes are temporarily dropped across sget() and inode mutex locking, which looks quite ridiculous; however, these will be removed through kernfs conversion and structuring the code this way makes the conversion less painful. The error goto labels are consolidated to two. This looks unwieldy now but the next patch will factor out creation of new root into a separate function with accompanying error handling and it'll look a lot better. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4ac0601744eb86e982fbdadde35f1945f7ce5882 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: release cgroup_mutex over file removals Now that cftypes and all tree modification operations are protected by cgroup_tree_mutex, we can drop cgroup_mutex while deleting files and directories. Drop cgroup_mutex over removals. This doesn't make any noticeable difference now but is to help kernfs conversion. In kernfs, removals are sync points which drain in-flight operations as those operations would grab cgroup_mutex, trying to delete under cgroup_mutex would deadlock. This can be resolved by just holding the outer cgroup_tree_mutex which nests outside both kernfs active reference and cgroup_mutex. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ace2bee8135a3dc725958b8d08c55ee9df813d39 |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce cgroup_tree_mutex Currently cgroup uses combination of inode->i_mutex'es and cgroup_mutex for synchronization. With the scheduled kernfs conversion, i_mutex'es will be removed. Unfortunately, just using cgroup_mutex isn't possible. All kernfs file and syscall operations, most of which require grabbing cgroup_mutex, will be called with kernfs active ref held and, if we try to perform kernfs removals under cgroup_mutex, it can deadlock as kernfs_remove() tries to drain the target node. Let's introduce a new outer mutex, cgroup_tree_mutex, which protects stuff used during hierarchy changing operations - cftypes and all the operations which may affect the cgroupfs. It also covers css association and iteration. This allows cgroup_css(), for_each_css() and other css iterators to be called under cgroup_tree_mutex. The new mutex will nest above both kernfs's active ref protection and cgroup_mutex. By protecting tree modifications with a separate outer mutex, we can get rid of the forementioned deadlock condition. Actual file additions and removals now require cgroup_tree_mutex instead of cgroup_mutex. Currently, cgroup_tree_mutex is never used without cgroup_mutex; however, we'll soon add hierarchy modification sections which are only protected by cgroup_tree_mutex. In the future, we might want to make the locking more granular by better splitting the coverages of the two mutexes. For now, this should do. v2: Rebased on top of 0ab02ca8f887 ("cgroup: protect modifications to cgroup_idr with cgroup_mutex"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5a17f543ed6808e9085063277fe46795dea484bd |
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11-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: improve css_from_dir() into css_tryget_from_dir() css_from_dir() returns the matching css (cgroup_subsys_state) given a dentry and subsystem. The function doesn't pin the css before returning and requires the caller to be holding RCU read lock or cgroup_mutex and handling pinning on the caller side. Given that users of the function are likely to want to pin the returned css (both existing users do) and that getting and putting css's are very cheap, there's no reason for the interface to be tricky like this. Rename css_from_dir() to css_tryget_from_dir() and make it try to pin the found css and return it only if pinning succeeded. The callers are updated so that they no longer do RCU locking and pinning around the function and just use the returned css. This will also ease converting cgroup to kernfs. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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0ab02ca8f887908152d1a96db5130fc661d36a1e |
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11-Feb-2014 |
Li Zefan <lizefan@huawei.com> |
cgroup: protect modifications to cgroup_idr with cgroup_mutex Setup cgroupfs like this: # mount -t cgroup -o cpuacct xxx /cgroup # mkdir /cgroup/sub1 # mkdir /cgroup/sub2 Then run these two commands: # for ((; ;)) { mkdir /cgroup/sub1/tmp && rmdir /mnt/sub1/tmp; } & # for ((; ;)) { mkdir /cgroup/sub2/tmp && rmdir /mnt/sub2/tmp; } & After seconds you may see this warning: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 25243 at lib/idr.c:527 sub_remove+0x87/0x1b0() idr_remove called for id=6 which is not allocated. ... Call Trace: [<ffffffff8156063c>] dump_stack+0x7a/0x96 [<ffffffff810591ac>] warn_slowpath_common+0x8c/0xc0 [<ffffffff81059296>] warn_slowpath_fmt+0x46/0x50 [<ffffffff81300aa7>] sub_remove+0x87/0x1b0 [<ffffffff810f3f02>] ? css_killed_work_fn+0x32/0x1b0 [<ffffffff81300bf5>] idr_remove+0x25/0xd0 [<ffffffff810f2bab>] cgroup_destroy_css_killed+0x5b/0xc0 [<ffffffff810f4000>] css_killed_work_fn+0x130/0x1b0 [<ffffffff8107cdbc>] process_one_work+0x26c/0x550 [<ffffffff8107eefe>] worker_thread+0x12e/0x3b0 [<ffffffff81085f96>] kthread+0xe6/0xf0 [<ffffffff81570bac>] ret_from_fork+0x7c/0xb0 ---[ end trace 2d1577ec10cf80d0 ]--- It's because allocating/removing cgroup ID is not properly synchronized. The bug was introduced when we converted cgroup_ida to cgroup_idr. While synchronization is already done inside ida_simple_{get,remove}(), users are responsible for concurrent calls to idr_{alloc,remove}(). tj: Refreshed on top of b58c89986a77 ("cgroup: fix error return from cgroup_create()"). Fixes: 4e96ee8e981b ("cgroup: convert cgroup_ida to cgroup_idr") Cc: <stable@vger.kernel.org> #3.12+ Reported-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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3417ae1f5f59bbf36c3defbbf2a76c5ca498db2a |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_root_mutex cgroup_root_mutex was added to avoid deadlock involving namespace_sem via cgroup_show_options(). It added a lot of overhead for the small purpose of it and, because it's nested under cgroup_mutex, it has very limited usefulness. The previous patch made cgroup_show_options() not use cgroup_root_mutex, so nobody needs it anymore. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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69e943b7d3c2dcca1087e03e556ac6cb0d4433b4 |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: update locking in cgroup_show_options() cgroup_show_options() grabs cgroup_root_mutex to protect the options changing while printing; however, holding root_mutex or not doesn't really make much difference for the function. subsys_mask can be atomically tested and most of the options aren't allowed to change anyway once mounted. The only field which needs synchronization is ->release_agent_path. This patch introduces a dedicated spinlock to synchronize accesses to the field and drops cgroup_root_mutex locking from cgroup_show_options(). The next patch will remove cgroup_root_mutex. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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aec25020f5d4b69aea5317551d1cb7043f6b04fb |
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08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_subsys->subsys_id to ->id It's no longer referenced outside cgroup core, so renaming is easy. Let's rename it for consistency & brevity. This patch is pure rename. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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073219e995b4a3f8cf1ce8228b7ef440b6994ac0 |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: clean up cgroup_subsys names and initialization cgroup_subsys is a bit messier than it needs to be. * The name of a subsys can be different from its internal identifier defined in cgroup_subsys.h. Most subsystems use the matching name but three - cpu, memory and perf_event - use different ones. * cgroup_subsys_id enums are postfixed with _subsys_id and each cgroup_subsys is postfixed with _subsys. cgroup.h is widely included throughout various subsystems, it doesn't and shouldn't have claim on such generic names which don't have any qualifier indicating that they belong to cgroup. * cgroup_subsys->subsys_id should always equal the matching cgroup_subsys_id enum; however, we require each controller to initialize it and then BUG if they don't match, which is a bit silly. This patch cleans up cgroup_subsys names and initialization by doing the followings. * cgroup_subsys_id enums are now postfixed with _cgrp_id, and each cgroup_subsys with _cgrp_subsys. * With the above, renaming subsys identifiers to match the userland visible names doesn't cause any naming conflicts. All non-matching identifiers are renamed to match the official names. cpu_cgroup -> cpu mem_cgroup -> memory perf -> perf_event * controllers no longer need to initialize ->subsys_id and ->name. They're generated in cgroup core and set automatically during boot. * Redundant cgroup_subsys declarations removed. * While updating BUG_ON()s in cgroup_init_early(), convert them to WARN()s. BUGging that early during boot is stupid - the kernel can't print anything, even through serial console and the trap handler doesn't even link stack frame properly for back-tracing. This patch doesn't introduce any behavior changes. v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs classid handling into core"). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: "David S. Miller" <davem@davemloft.net> Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Ingo Molnar <mingo@redhat.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Thomas Graf <tgraf@suug.ch>
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3ed80a62bf959d34ebd4d553b026fbe7e6fbcc54 |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: drop module support With module supported dropped from net_prio, no controller is using cgroup module support. None of actual resource controllers can be built as a module and we aren't gonna add new controllers which don't control resources. This patch drops module support from cgroup. * cgroup_[un]load_subsys() and cgroup_subsys->module removed. * As there's no point in distinguishing IS_BUILTIN() and IS_MODULE(), cgroup_subsys.h now uses IS_ENABLED() directly. * enum cgroup_subsys_id now exactly matches the list of enabled controllers as ordered in cgroup_subsys.h. * cgroup_subsys[] is now a contiguously occupied array. Size specification is no longer necessary and dropped. * for_each_builtin_subsys() is removed and for_each_subsys() is updated to not require any locking. * module ref handling is removed from rebind_subsystems(). * Module related comments dropped. v2: Rebased on top of fe1217c4f3f7 ("net: net_cls: move cgroupfs classid handling into core"). v3: Added {} around the if (need_forkexit_callback) block in cgroup_post_fork() for readability as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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48573a893303986e3b0b2974d6fb11f3d1bb7064 |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: fix locking in cgroup_cfts_commit() cgroup_cfts_commit() walks the cgroup hierarchy that the target subsystem is attached to and tries to apply the file changes. Due to the convolution with inode locking, it can't keep cgroup_mutex locked while iterating. It currently holds only RCU read lock around the actual iteration and then pins the found cgroup using dget(). Unfortunately, this is incorrect. Although the iteration does check cgroup_is_dead() before invoking dget(), there's nothing which prevents the dentry from going away inbetween. Note that this is different from the usual css iterations where css_tryget() is used to pin the css - css_tryget() tests whether the css can be pinned and fails if not. The problem can be solved by simply holding cgroup_mutex instead of RCU read lock around the iteration, which actually reduces LOC. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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b58c89986a77a23658682a100eb15d8edb571ebb |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: fix error return from cgroup_create() cgroup_create() was returning 0 after allocation failures. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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eb46bf89696972b856a9adb6aebd5c7b65c266e4 |
|
08-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: fix error return value in cgroup_mount() When cgroup_mount() fails to allocate an id for the root, it didn't set ret before jumping to unlock_drop ending up returning 0 after a failure. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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ab3f5faa6255a0eb4f832675507d9e295ca7e9ba |
|
07-Feb-2014 |
Hugh Dickins <hughd@google.com> |
cgroup: use an ordered workqueue for cgroup destruction Sometimes the cleanup after memcg hierarchy testing gets stuck in mem_cgroup_reparent_charges(), unable to bring non-kmem usage down to 0. There may turn out to be several causes, but a major cause is this: the workitem to offline parent can get run before workitem to offline child; parent's mem_cgroup_reparent_charges() circles around waiting for the child's pages to be reparented to its lrus, but it's holding cgroup_mutex which prevents the child from reaching its mem_cgroup_reparent_charges(). Just use an ordered workqueue for cgroup_destroy_wq. tj: Committing as the temporary fix until the reverse dependency can be removed from memcg. Comment updated accordingly. Fixes: e5fca243abae ("cgroup: use a dedicated workqueue for cgroup destruction") Suggested-by: Filipe Brandenburger <filbranden@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: stable@vger.kernel.org # 3.10+ Signed-off-by: Tejun Heo <tj@kernel.org>
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dd4b0a4676907481256d16d5de0851b315a6f22c |
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18-Jan-2014 |
SeongJae Park <sj38.park@gmail.com> |
cgroup: trivial style updates * Place newline before function opening brace in cgroup_kill_sb(). * Insert space before assignment in attach_task_by_pid() tj: merged two patches into one. Signed-off-by: SeongJae Park <sj38.park@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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c1a71504e9715812a2d15e7c03b5aa147ae70ded |
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17-Dec-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: don't recycle cgroup id until all csses' have been destroyed Hugh reported this bug: > CONFIG_MEMCG_SWAP is broken in 3.13-rc. Try something like this: > > mkdir -p /tmp/tmpfs /tmp/memcg > mount -t tmpfs -o size=1G tmpfs /tmp/tmpfs > mount -t cgroup -o memory memcg /tmp/memcg > mkdir /tmp/memcg/old > echo 512M >/tmp/memcg/old/memory.limit_in_bytes > echo $$ >/tmp/memcg/old/tasks > cp /dev/zero /tmp/tmpfs/zero 2>/dev/null > echo $$ >/tmp/memcg/tasks > rmdir /tmp/memcg/old > sleep 1 # let rmdir work complete > mkdir /tmp/memcg/new > umount /tmp/tmpfs > dmesg | grep WARNING > rmdir /tmp/memcg/new > umount /tmp/memcg > > Shows lots of WARNING: CPU: 1 PID: 1006 at kernel/res_counter.c:91 > res_counter_uncharge_locked+0x1f/0x2f() > > Breakage comes from 34c00c319ce7 ("memcg: convert to use cgroup id"). > > The lifetime of a cgroup id is different from the lifetime of the > css id it replaced: memsw's css_get()s do nothing to hold on to the > old cgroup id, it soon gets recycled to a new cgroup, which then > mysteriously inherits the old's swap, without any charge for it. Instead of removing cgroup id right after all the csses have been offlined, we should do that after csses have been destroyed. To make sure an invalid css pointer won't be returned after the css is destroyed, make sure css_from_id() returns NULL in this case. tj: Updated comment to note planned changes for cgrp->id. Reported-by: Hugh Dickins <hughd@google.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org>
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10bf2f7e7db993273419ca9f51f5934e4cf71768 |
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12-Dec-2013 |
Vladimir Davydov <vdavydov@parallels.com> |
cgroup: fix fail path in cgroup_load_subsys() Calling cgroup_unload_subsys() from cgroup_load_subsys() after online_css() failure will result in a NULL ptr dereference on attempt to offline_css(), because online_css() only assigns css to cgroup on success. Let's fix that by skipping calls to offline_css() and css_free() in cgroup_unload_subsys() if there is no css, and freeing css in cgroup_load_subsys() on online_css() failure. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0be8669dd530f60cf3f59f084518570c1dfb47ee |
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09-Dec-2013 |
Wei Yongjun <yongjun_wei@trendmicro.com.cn> |
cgroup: fix missing unlock on error in cgroup_load_subsys() Add the missing unlock before return from function cgroup_load_subsys() in the error handling case. Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b85d20404cef6493f9d2edbafe83f9c72aece9a8 |
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06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove for_each_root_subsys() After the previous patch which introduced for_each_css(), for_each_root_subsys() only has two users left. This patch replaces it with for_each_subsys() + explicit subsys_mask testing and remove for_each_root_subsys() along with cgroupfs_root->subsys_list handling. This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1c6727af4b495a9ec74c46d1fc08e508e675899d |
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06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement for_each_css() There are enough places where css's of a cgroup are iterated, which currently uses for_each_root_subsys() + explicit cgroup_css(). This patch implements for_each_css() and replaces the above combination with it. This patch doesn't introduce any behavior changes. v2: Updated to apply cleanly on top of v2 of "cgroup: fix css leaks on online_css() failure" Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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c81c925ad9b0460a14ec35b52c61158da0733d51 |
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06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: factor out cgroup_subsys_state creation into create_css() Now that all opertations to create a css (cgroup_subsys_state) are collected into a single loop in cgroup_create(), it's easy to factor it out into its own function. Factor out css creation into create_css(). This makes the code easier to follow and will enable decoupling css creation from cgroup creation which is necessary for the planned unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9d403e99238ed6d7151a2c07db6cf8f6932ef3d5 |
|
06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: combine css handling loops in cgroup_create() Now that css operations in cgroup_create() are back-to-back, there isn't much point in allocating css's in one loop and onlining them in another. Merge the two loops so that a css is allocated and onlined on each iteration. css_ar[] is no longer necessary and replaced with a single pointer. This also simplifies the error handling path. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0d80255e42b54419cfc6b10a3ec74b60fe04b8d7 |
|
06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: reorder operations in cgroup_create() cgroup_create() currently does the followings. 1. alloc cgroup 2. alloc css's 3. create the directory and commit to cgroup creation 4. online css's 5. create cgroup and css files The sequence performs allocations before other operations but it doesn't buy anything because each of the above steps may fail and should be unrollable. Reorganize the sequence such that cgroup operations are done before css operations. 1. alloc cgroup 2. create the directory and files and commit to cgroup creation 3. alloc css's 4. create files for and online css's This simplifies the code a bit and enables further simplification and separating out css creation from cgroup creation which is necessary for the planned unified hierarchy where css's will be created and destroyed dynamically across the lifetime of a cgroup. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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780cd8b347b52584704438e599274f25c0a0fd13 |
|
06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make for_each_subsys() useable under cgroup_root_mutex We want to use for_each_subsys() in cgroupfs_root handling where only cgroup_root_mutex is held. The only way cgroup_subsys[] can change is through module load/unload, make cgroup_[un]load_subsys() grab cgroup_root_mutex too and update the lockdep annotation in for_each_subsys() to allow either cgroup_mutex or cgroup_root_mutex. * Lockdep annotation is moved from inner 'if' condition to outer 'for' init caluse. There's no reason to execute the assertion every loop. * Loop index @i is renamed to @ssid. Indices iterating through subsys will be [re]named to @ssid gradually. v2: cgroup_assert_mutex_or_root_locked() caused build failure if !CONFIG_LOCKEDP. Conditionalize its definition. The build failure was reported by kbuild test bot. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: kbuild test robot <fengguang.wu@intel.com>
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87fb54f1b5a447662854f176eeb1ba92d5ffc1d5 |
|
06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: css iterations and css_from_dir() are safe under cgroup_mutex Currently, all css iterations and css_from_dir() require RCU read lock whether the caller is holding cgroup_mutex or not, which is unnecessarily restrictive. They are all safe to use under cgroup_mutex without holding RCU read lock. Factor out cgroup_assert_mutex_or_rcu_locked() from css_from_id() and apply it to all css iteration functions and css_from_dir(). v2: cgroup_assert_mutex_or_rcu_locked() definition doesn't need to be inside CONFIG_PROVE_RCU ifdef as rcu_lockdep_assert() is always defined and conditionalized. Move it outside of the ifdef block. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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266ccd505e8acb98717819cef9d91d66c7b237cc |
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06-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_create() error handling path ae7f164a09 ("cgroup: move cgroup->subsys[] assignment to online_css()") moved cgroup->subsys[] assignements later in cgroup_create() but didn't update error handling path accordingly leading to the following oops and leaking later css's after an online_css() failure. The oops is from cgroup destruction path being invoked on the partially constructed cgroup which is not ready to handle empty slots in cgrp->subsys[] array. BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 IP: [<ffffffff810eeaa8>] cgroup_destroy_locked+0x118/0x2f0 PGD a780a067 PUD aadbe067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 6 PID: 7360 Comm: mkdir Not tainted 3.13.0-rc2+ #69 Hardware name: task: ffff8800b9dbec00 ti: ffff8800a781a000 task.ti: ffff8800a781a000 RIP: 0010:[<ffffffff810eeaa8>] [<ffffffff810eeaa8>] cgroup_destroy_locked+0x118/0x2f0 RSP: 0018:ffff8800a781bd98 EFLAGS: 00010282 RAX: ffff880586903878 RBX: ffff880586903800 RCX: ffff880586903820 RDX: ffff880586903860 RSI: ffff8800a781bdb0 RDI: ffff880586903820 RBP: ffff8800a781bde8 R08: ffff88060e0b8048 R09: ffffffff811d7bc1 R10: 000000000000008c R11: 0000000000000001 R12: ffff8800a72286c0 R13: 0000000000000000 R14: ffffffff81cf7a40 R15: 0000000000000001 FS: 00007f60ecda57a0(0000) GS:ffff8806272c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 00000000a7a03000 CR4: 00000000000007e0 Stack: ffff880586903860 ffff880586903910 ffff8800a72286c0 ffff880586903820 ffffffff81cf7a40 ffff880586903800 ffff88060e0b8018 ffffffff81cf7a40 ffff8800b9dbec00 ffff8800b9dbf098 ffff8800a781bec8 ffffffff810ef5bf Call Trace: [<ffffffff810ef5bf>] cgroup_mkdir+0x55f/0x5f0 [<ffffffff811c90ae>] vfs_mkdir+0xee/0x140 [<ffffffff811cb07e>] SyS_mkdirat+0x6e/0xf0 [<ffffffff811c6a19>] SyS_mkdir+0x19/0x20 [<ffffffff8169e569>] system_call_fastpath+0x16/0x1b This patch moves reference bumping inside online_css() loop, clears css_ar[] as css's are brought online successfully, and updates err_destroy path so that either a css is fully online and destroyed by cgroup_destroy_locked() or the error path frees it. This creates a duplicate css free logic in the error path but it will be cleaned up soon. v2: Li pointed out that cgroup_destroy_locked() would do NULL-deref if invoked with a cgroup which doesn't have all css's populated. Update cgroup_destroy_locked() so that it skips NULL css's. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Reported-by: Vladimir Davydov <vdavydov@parallels.com> Cc: stable@vger.kernel.org # v3.12+
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6612f05b88fa309c91a345690411217959bb2486 |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unify pidlist and other file handling In preparation of conversion to kernfs, cgroup file handling is updated so that it can be easily mapped to kernfs. With the previous changes, the difference between pidlist and other files are very small. Both are served by seq_file in a pretty standard way with the only difference being !pidlist files use single_open(). This patch adds cftype->seq_start(), ->seq_next and ->seq_stop() and implements the matching cgroup_seqfile_start/next/stop() which either emulates single_open() behavior or invokes cftype->seq_*() operations if specified. This allows using single seq_operations for both pidlist and other files and makes cgroup_pidlist_operations and cgorup_pidlist_open() no longer necessary. As cgroup_pidlist_open() was the only user of cftype->open(), the method is dropped together. This brings cftype file interface very close to kernfs interface and mapping shouldn't be too difficult. Once converted to kernfs, most of the plumbing code including cgroup_seqfile_*() will be removed as kernfs provides those facilities. This patch does not introduce any behavior changes. v2: Refreshed on top of the updated "cgroup: introduce struct cgroup_pidlist_open_file". v3: Refreshed on top of the updated "cgroup: attach cgroup_open_file to all cgroup files". Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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2da8ca822d49c8b8781800ad155aaa00e7bb5f1a |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: replace cftype->read_seq_string() with cftype->seq_show() In preparation of conversion to kernfs, cgroup file handling is updated so that it can be easily mapped to kernfs. This patch replaces cftype->read_seq_string() with cftype->seq_show() which is not limited to single_open() operation and will map directcly to kernfs seq_file interface. The conversions are mechanical. As ->seq_show() doesn't have @css and @cft, the functions which make use of them are converted to use seq_css() and seq_cft() respectively. In several occassions, e.f. if it has seq_string in its name, the function name is updated to fit the new method better. This patch does not introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Aristeu Rozanski <arozansk@redhat.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Neil Horman <nhorman@tuxdriver.com>
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7da112792753d71aed44b918395892a1fc53048a |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: attach cgroup_open_file to all cgroup files In preparation of conversion to kernfs, cgroup file handling is updated so that it can be easily mapped to kernfs. This patch attaches cgroup_open_file, which used to be attached to pidlist files, to all cgroup files, introduces seq_css/cft() accessors to determine the cgroup_subsys_state and cftype associated with a given cgroup seq_file, exports them as public interface. This doesn't cause any behavior changes but unifies cgroup file handling across different file types and will help converting them to kernfs seq_show() interface. v2: Li pointed out that the original patch was using single_open_size() incorrectly assuming that the size param is private data size. Fix it by allocating @of separately and passing it to single_open() and explicitly freeing it in the release path. This isn't the prettiest but this path is gonna be restructured by the following patches pretty soon. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5d22444f427511fe7c4733b233680309af5b071c |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: generalize cgroup_pidlist_open_file In preparation of conversion to kernfs, cgroup file handling is updated so that it can be easily mapped to kernfs. This patch renames cgroup_pidlist_open_file to cgroup_open_file and updates it so that it only contains a field to identify the specific file, ->cfe, and an opaque ->priv pointer. When cgroup is converted to kernfs, this will be replaced by kernfs_open_file which contains about the same information. As whether the file is "cgroup.procs" or "tasks" should now be determined from cgroup_open_file->cfe, the cftype->private for the two files now carry the file type and cgroup_pidlist_start() reads the type through cfe->type->private. This makes the distinction between cgroup_tasks_open() and cgroup_procs_open() unnecessary. cgroup_pidlist_open() is now directly used as the open method. This patch doesn't make any behavior changes. v2: Refreshed on top of the updated "cgroup: introduce struct cgroup_pidlist_open_file". Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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896f5199631560202885715da1b2f018632084e5 |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unify read path so that seq_file is always used With the recent removal of cftype->read() and ->read_map(), only three operations are remaining, ->read_u64(), ->read_s64() and ->read_seq_string(). Currently, the first two are handled directly while the last is handled through seq_file. It is trivial to serve the first two through the seq_file path too. This patch restructures read path so that all operations are served through cgroup_seqfile_show(). This makes all cgroup files seq_file - single_open/release() are now used by default, cgroup_seqfile_operations is dropped, and cgroup_file_operations uses seq_read() for read. This simplifies the code and makes the read path easy to convert to use kernfs. Note that, while cgroup_file_operations uses seq_read() for read, it still uses generic_file_llseek() for seeking instead of seq_lseek(). This is different from cgroup_seqfile_operations but shouldn't break anything and brings the seeking behavior aligned with kernfs. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a742c59de66ea080afa3edaf3428b3cdd5aa87cd |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unify cgroup_write_X64() and cgroup_write_string() cgroup_write_X64() and cgroup_write_string() both implement about the same buffering logic. Unify the two into cgroup_file_write() which always allocates dynamic buffer for simplicity and uses kstrto*() instead of simple_strto*(). This patch doesn't make any visible behavior changes except for possibly different error value from kstrsto*(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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6e0755b08dd6a3b5260fafc6969268c2ba261300 |
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05-Dec-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cftype->read(), ->read_map() and ->write() In preparation of conversion to kernfs, cgroup file handling is being consolidated so that it can be easily mapped to the seq_file based interface of kernfs. After recent updates, ->read() and ->read_map() don't have any user left and ->write() never had any user. Remove them. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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afb2bc14e1c989cf0635bd04edb5ff55b8c1c7bd |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: don't guarantee cgroup.procs is sorted if sane_behavior For some reason, tasks and cgroup.procs guarantee that the result is sorted. This is the only reason this whole pidlist logic is necessary instead of just iterating through sorted member tasks. We can't do anything about the existing interface but at least ensure that such expectation doesn't exist for the new interface so that pidlist logic may be removed in the distant future. This patch scrambles the sort order if sane_behavior so that the output is usually not sorted in the new interface. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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045023658ca1e30dc0bb1f148b42c95b740d3e02 |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_pidlist->use_count After the recent changes, pidlist ref is held only between cgroup_pidlist_start() and cgroup_pidlist_stop() during which cgroup->pidlist_mutex is also held. IOW, the reference count is redundant now. While in use, it's always one and pidlist_mutex is held - holding the mutex has exactly the same protection. This patch collapses destroy_dwork queueing into cgroup_pidlist_stop() so that pidlist_mutex is not released inbetween and drops pidlist->use_count. This patch shouldn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4bac00d16a8760eae7205e41d2c246477d42a210 |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: load and release pidlists from seq_file start and stop respectively Currently, pidlists are reference counted from file open and release methods. This means that holding onto an open file may waste memory and reads may return data which is very stale. Both aren't critical because pidlists are keyed and shared per namespace and, well, the user isn't supposed to have large delay between open and reads. cgroup is planned to be converted to use kernfs and it'd be best if we can stick to just the seq_file operations - start, next, stop and show. This can be achieved by loading pidlist on demand from start and release with time delay from stop, so that consecutive reads don't end up reloading the pidlist on each iteration. This would remove the need for hooking into open and release while also avoiding issues with holding onto pidlist for too long. The previous patches implemented delayed release and restructured pidlist handling so that pidlists can be loaded and released from seq_file start / stop. This patch actually moves pidlist load to start and release to stop. This means that pidlist is pinned only between start and stop and may go away between two consecutive read calls if the two calls are apart by more than CGROUP_PIDLIST_DESTROY_DELAY. cgroup_pidlist_start() thus can't re-use the stored cgroup_pid_list_open_file->pidlist directly. During start, it's only used as a hint indicating whether this is the first start after open or not and pidlist is always looked up or created. pidlist_mutex locking and reference counting are moved out of pidlist_array_load() so that pidlist_array_load() can perform lookup and creation atomically. While this enlarges the area covered by pidlist_mutex, given how the lock is used, it's highly unlikely to be noticeable. v2: Refreshed on top of the updated "cgroup: introduce struct cgroup_pidlist_open_file". Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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069df3b7aeb3f4e926c4da9630c92010909af512 |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_pidlist->rwsem cgroup_pidlist locking is needlessly complicated. It has outer cgroup->pidlist_mutex to protect the list of pidlists associated with a cgroup and then each pidlist has rwsem to synchronize updates and reads. Given that the only read access is from seq_file operations which are always invoked back-to-back, the rwsem is a giant overkill. All it does is adding unnecessary complexity. This patch removes cgroup_pidlist->rwsem and protects all accesses to pidlists belonging to a cgroup with cgroup->pidlist_mutex. pidlist->rwsem locking is removed if it's nested inside cgroup->pidlist_mutex; otherwise, it's replaced with cgroup->pidlist_mutex locking. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e6b817103d168a76e4044ebcdbc08225d77a81cb |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: refactor cgroup_pidlist_find() Rename cgroup_pidlist_find() to cgroup_pidlist_find_create() and separate out finding proper to cgroup_pidlist_find(). Also, move locking to the caller. This patch is preparation for pidlist restructure and doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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62236858f3cc558135d1ab6b2af44d22c489bb7f |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce struct cgroup_pidlist_open_file For pidlist files, seq_file->private pointed to the loaded cgroup_pidlist; however, pidlist loading is planned to be moved to cgroup_pidlist_start() for kernfs conversion and seq_file->private needs to carry more information from open to allow that. This patch introduces struct cgroup_pidlist_open_file which contains type, cgrp and pidlist and updates pidlist seq_file->private to point to it using seq_open_private() and seq_release_private(). Note that this eventually will be replaced by kernfs_open_file. While this patch makes more information available to seq_file operations, they don't use it yet and this patch doesn't introduce any behavior changes except for allocation of the extra private struct. v2: use __seq_open_private() instead of seq_open_private() for brevity as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b1a21367314f36a819c0676e0999f34db12ee6ed |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement delayed destruction for cgroup_pidlist Currently, pidlists are reference counted from file open and release methods. This means that holding onto an open file may waste memory and reads may return data which is very stale. Both aren't critical because pidlists are keyed and shared per namespace and, well, the user isn't supposed to have large delay between open and reads. cgroup is planned to be converted to use kernfs and it'd be best if we can stick to just the seq_file operations - start, next, stop and show. This can be achieved by loading pidlist on demand from start and release with time delay from stop, so that consecutive reads don't end up reloading the pidlist on each iteration. This would remove the need for hooking into open and release while also avoiding issues with holding onto pidlist for too long. This patch implements delayed release of pidlist. As pidlists could be lingering on cgroup removal waiting for the timer to expire, cgroup free path needs to queue the destruction work item immediately and flush. As those work items are self-destroying, each work item can't be flushed directly. A new workqueue - cgroup_pidlist_destroy_wq - is added to serve as flush domain. Note that this patch just adds delayed release on top of the current implementation and doesn't change where pidlist is loaded and released. Following patches will make those changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b9f3cecaba592d4e98cd155c91b1414323ed51e8 |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cftype->release() Now that pidlist files don't use cftype->release(), it doesn't have any user left. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ac1e69aa78e2e799a8d5475595ba744bdf29b597 |
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29-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: don't skip seq_open on write only opens on pidlist files Currently, cgroup_pidlist_open() skips seq_open() and pidlist loading if the file is opened write-only, which is a sensible optimization as pidlist loading can be costly and there often are occasions where tasks or cgroup.procs is opened write-only. However, pidlist init and release are planned to be moved to cgroup_pidlist_start/stop() respectively which would make this optimization unnecessary. This patch removes the optimization and always fully initializes pidlist files regardless of open mode. This will help moving pidlist handling to start/stop by unifying rw paths and removes the need for specifying cftype->release() in addition to .release in cgroup_pidlist_operations as file->f_op is now always overridden. As pidlist files were the only user of cftype->release(), the next patch will remove the method. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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e605b36575e896edd8161534550c9ea021b03bc0 |
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28-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_subsys_state leak for seq_files If a cgroup file implements either read_map() or read_seq_string(), such file is served using seq_file by overriding file->f_op to cgroup_seqfile_operations, which also overrides the release method to single_release() from cgroup_file_release(). Because cgroup_file_open() didn't use to acquire any resources, this used to be fine, but since f7d58818ba42 ("cgroup: pin cgroup_subsys_state when opening a cgroupfs file"), cgroup_file_open() pins the css (cgroup_subsys_state) which is put by cgroup_file_release(). The patch forgot to update the release path for seq_files and each open/release cycle leaks a css reference. Fix it by updating cgroup_file_release() to also handle seq_files and using it for seq_file release path too. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org # v3.12
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b36824c75c7855585d6476eef2b234f6e0e68872 |
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23-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unexport cgroup_css() and remove __file_cft() Now that cgroup_event is made memcg specific, the temporarily exported functions are no longer necessary. Unexport cgroup_css() and remove __file_cft() which doesn't have any user left. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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fba94807837850e211f8975e1970e23e7804ff4d |
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23-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup, memcg: move cgroup->event_list[_lock] and event callbacks into memcg cgroup_event is being moved from cgroup core to memcg and the implementation is already moved by the previous patch. This patch moves the data fields and callbacks. * cgroup->event_list[_lock] are moved to mem_cgroup. * cftype->[un]register_event() are moved to cgroup_event. This makes it impossible for individual cftype definitions to specify their event callbacks. This is worked around by simply hard-coding filename to event callback mapping in cgroup_write_event_control(). This is awkward and inflexible, which is actually desirable given that we don't want to grow more usages of this feature. * eventfd_ctx declaration is removed from cgroup.h, which makes vmpressure.h miss eventfd_ctx declaration. Include eventfd.h from vmpressure.h. v2: Use file name from dentry instead of cftype. This will allow removing all cftype handling in the function. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
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79bd9814e5ec9a288d6599f53aeac0b548fdfe52 |
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23-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup, memcg: move cgroup_event implementation to memcg cgroup_event is way over-designed and tries to build a generic flexible event mechanism into cgroup - fully customizable event specification for each user of the interface. This is utterly unnecessary and overboard especially in the light of the planned unified hierarchy as there's gonna be single agent. Simply generating events at fixed points, or if that's too restrictive, configureable cadence or single set of configureable points should be enough. Thankfully, memcg is the only user and gets to keep it. Replacing it with something simpler on sane_behavior is strongly recommended. This patch moves cgroup_event and "cgroup.event_control" implementation to mm/memcontrol.c. Clearing of events on cgroup destruction is moved from cgroup_destroy_locked() to mem_cgroup_css_offline(), which shouldn't make any noticeable difference. cgroup_css() and __file_cft() are exported to enable the move; however, this will soon be reverted once the event code is updated to be memcg specific. Note that "cgroup.event_control" will now exist only on the hierarchy with memcg attached to it. While this change is visible to userland, it is unlikely to be noticeable as the file has never been meaningful outside memcg. Aside from the above change, this is pure code relocation. v2: Per Li Zefan's comments, init/Kconfig updated accordingly and poll.h inclusion moved from cgroup.c to memcontrol.c. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
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e5fca243abae1445afbfceebda5f08462ef869d3 |
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22-Nov-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: use a dedicated workqueue for cgroup destruction Since be44562613851 ("cgroup: remove synchronize_rcu() from cgroup_diput()"), cgroup destruction path makes use of workqueue. css freeing is performed from a work item from that point on and a later commit, ea15f8ccdb430 ("cgroup: split cgroup destruction into two steps"), moves css offlining to workqueue too. As cgroup destruction isn't depended upon for memory reclaim, the destruction work items were put on the system_wq; unfortunately, some controller may block in the destruction path for considerable duration while holding cgroup_mutex. As large part of destruction path is synchronized through cgroup_mutex, when combined with high rate of cgroup removals, this has potential to fill up system_wq's max_active of 256. Also, it turns out that memcg's css destruction path ends up queueing and waiting for work items on system_wq through work_on_cpu(). If such operation happens while system_wq is fully occupied by cgroup destruction work items, work_on_cpu() can't make forward progress because system_wq is full and other destruction work items on system_wq can't make forward progress because the work item waiting for work_on_cpu() is holding cgroup_mutex, leading to deadlock. This can be fixed by queueing destruction work items on a separate workqueue. This patch creates a dedicated workqueue - cgroup_destroy_wq - for this purpose. As these work items shouldn't have inter-dependencies and mostly serialized by cgroup_mutex anyway, giving high concurrency level doesn't buy anything and the workqueue's @max_active is set to 1 so that destruction work items are executed one by one on each CPU. Hugh Dickins: Because cgroup_init() is run before init_workqueues(), cgroup_destroy_wq can't be allocated from cgroup_init(). Do it from a separate core_initcall(). In the future, we probably want to reorder so that workqueue init happens before cgroup_init(). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Hugh Dickins <hughd@google.com> Reported-by: Shawn Bohrer <shawn.bohrer@gmail.com> Link: http://lkml.kernel.org/r/20131111220626.GA7509@sbohrermbp13-local.rgmadvisors.com Link: http://lkml.kernel.org/g/alpine.LNX.2.00.1310301606080.2333@eggly.anvils Cc: stable@vger.kernel.org # v3.9+
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b26d4cd385fc51e8844e2cdf9ba2051f5bba11a5 |
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26-Oct-2013 |
Al Viro <viro@zeniv.linux.org.uk> |
consolidate simple ->d_delete() instances Rename simple_delete_dentry() to always_delete_dentry() and export it. Export simple_dentry_operations, while we are at it, and get rid of their duplicates Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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ea84753c98a7ac6b74e530b64c444a912b3835ca |
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12-Oct-2013 |
Anjana V Kumar <anjanavk12@gmail.com> |
cgroup: fix to break the while loop in cgroup_attach_task() correctly Both Anjana and Eunki reported a stall in the while_each_thread loop in cgroup_attach_task(). It's because, when we attach a single thread to a cgroup, if the cgroup is exiting or is already in that cgroup, we won't break the loop. If the task is already in the cgroup, the bug can lead to another thread being attached to the cgroup unexpectedly: # echo 5207 > tasks # cat tasks 5207 # echo 5207 > tasks # cat tasks 5207 5215 What's worse, if the task to be attached isn't the leader of the thread group, we might never exit the loop, hence cpu stall. Thanks for Oleg's analysis. This bug was introduced by commit 081aa458c38ba576bdd4265fc807fa95b48b9e79 ("cgroup: consolidate cgroup_attach_task() and cgroup_attach_proc()") [ lizf: - fixed the first continue, pointed out by Oleg, - rewrote changelog. ] Cc: <stable@vger.kernel.org> # 3.9+ Reported-by: Eunki Kim <eunki_kim@samsung.com> Reported-by: Anjana V Kumar <anjanavk12@gmail.com> Signed-off-by: Anjana V Kumar <anjanavk12@gmail.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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2ff2a7d03bbe472ed44a8380dbdbea490d81c59d |
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23-Sep-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: kill css_id The only user of css_id was memcg, and it has been convered to use cgroup->id, so kill css_id. Signed-off-by: Li Zefan <lizefan@huwei.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Tejun Heo <tj@kernel.org>
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58b79a91f57efec9457de8ff93a4cc4fb8daf753 |
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06-Sep-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup post-order descendant walk of empty subtree bd8815a6d8 ("cgroup: make css_for_each_descendant() and friends include the origin css in the iteration") updated cgroup descendant iterators to include the origin css; unfortuantely, it forgot to drop special case handling in css_next_descendant_post() for empty subtree leading to failure to visit the origin css without any child. Fix it by dropping the special case handling and always returning the leftmost descendant on the first iteration. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4e10f3c98888ee88ea2543aa636db6410fa47477 |
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30-Aug-2013 |
Al Viro <viro@zeniv.linux.org.uk> |
Kill indirect include of file.h from eventfd.h, use fdget() in cgroup.c kernel/cgroup.c is the only place in the tree that relies on eventfd.h pulling file.h; move that include there. Switch from eventfd_fget()/fput() to fdget()/fdput(), while we are at it - eventfd_ctx_fileget() will fail on non-eventfd descriptors just fine, no need to do that check twice... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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bb78a92f47696b2da49f2692b6a9fa56d07c444a |
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29-Aug-2013 |
Hugh Dickins <hughd@google.com> |
cgroup: fix rmdir EBUSY regression in 3.11 On 3.11-rc we are seeing cgroup directories left behind when they should have been removed. Here's a trivial reproducer: cd /sys/fs/cgroup/memory mkdir parent parent/child; rmdir parent/child parent rmdir: failed to remove `parent': Device or resource busy It's because cgroup_destroy_locked() (step 1 of destruction) leaves cgroup on parent's children list, letting cgroup_offline_fn() (step 2 of destruction) remove it; but step 2 is run by work queue, which may not yet have removed the children when parent destruction checks the list. Fix that by checking through a non-empty list of children: if every one of them has already been marked CGRP_DEAD, then it's safe to proceed: those children are invisible to userspace, and should not obstruct rmdir. (I didn't see any reason to keep the cgrp->children checks under the unrelated css_set_lock, so moved them out.) tj: Flattened nested ifs a bit and updated comment so that it's correct on both for-3.11-fixes and for-3.12. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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d1625964da51bda61306ad3ec45307a799c21f08 |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_css() invocation in css_from_id() ca8bdcaff0 ("cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys") missed one conversion in css_from_id(), which was newly added. As css_from_id() doesn't have any user yet, this doesn't break anything other than generating a build warning. Convert it. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Reported-by: kbuild test robot <fengguang.wu@intel.com>
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7c918cbbd829669bf70ffcc45962d5d992942243 |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_write_event_control() use css_from_dir() instead of __d_cgrp() cgroup_event will be moved to its only user - memcg. Replace __d_cgrp() usage with css_from_dir(), which is already exported. This also simplifies the code a bit. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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7941cb027dccedec3c047271554ddcf4be2e0697 |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_event hold onto cgroup_subsys_state instead of cgroup Currently, each registered cgroup_event holds an extra reference to the cgroup. This is a bit weird as events are subsystem specific and will also be incorrect in the planned unified hierarchy as css (cgroup_subsys_state) may come and go dynamically across the lifetime of a cgroup. Holding onto cgroup won't prevent the target css from going away. Update cgroup_event to hold onto the css the traget file belongs to instead of cgroup. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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9fa4db334c7d9570aec7a5121e84fae99aae1d04 |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement CFTYPE_NO_PREFIX When cgroup files are created, cgroup core automatically prepends the name of the subsystem as prefix. This patch adds CFTYPE_NO_ which disables the automatic prefix. This is to work around historical baggages and shouldn't be used for new files. This will be used to move "cgroup.event_control" from cgroup core to memcg. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Glauber Costa <glommer@gmail.com>
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ca8bdcaff0d77990fb69e0f946018c96a70851cc |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys cgroup_css() is no longer used in hot paths. Make it take struct cgroup_subsys * and allow the users to specify NULL subsys to obtain the dummy_css. This removes open-coded NULL subsystem testing in a couple users and generally simplifies the code. After this patch, css_from_dir() also allows NULL @ss and returns the matching dummy_css. This behavior change doesn't affect its only user - perf. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
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35cf083619da5677f83e9a8eae813f0b413d7082 |
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27-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax cgroup_css_from_dir() will grow another user. In preparation, make the following changes. * All css functions are prefixed with just "css_", rename it to css_from_dir(). * Take dentry * instead of file * as dentry is what ultimately identifies a cgroup and file may not always be available. Note that the function now checkes whether @dentry->d_inode is NULL as the caller now may specify a negative dentry. * Make it take cgroup_subsys * instead of integer subsys_id. This simplifies the function and allows specifying no subsystem for cgroup->dummy_css. * Make return section a bit less verbose. This patch doesn't introduce any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com>
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6e6eab0efdf48fb2d8d7aee904d7740acb4661c6 |
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15-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_write_event_control() 81eeaf0411 ("cgroup: make cftype->[un]register_event() deal with cgroup_subsys_state inst ead of cgroup") updated the cftype event methods to take @css (cgroup_subsys_state) instead of @cgroup; however, it incorrectly used @css passed to cgroup_write_event_control(), which the dummy_css for the cgroup as the file is a cgroup core file. This leads to oops on event registration. Fix it by using the css matching the event target file. Note that cgroup_write_event_control() now disallows cgroup core files from being event sources. This is for simplicity and doesn't matter as cgroup_event will be moved and made specific to memcg. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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0bfb4aa67cef4982adc70590a31624d7b35a0bda |
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15-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix subsystem file accesses on the root cgroup 105347ba5 ("cgroup: make cgroup_file_open() rcu_read_lock() around cgroup_css() and add cfent->css") added cfent->css to cache the associted cgroup_subsys_state across file operations. A cfent is associated with single css throughout its lifetime and the origimal commit initialized the cache pointer during cgroup_add_file() and verified that it matches the actual one in cgroup_file_open(). While this works fine for !root cgroups, it's broken for root cgroups as files in a root cgroup are created before the css's are associated with the cgroup and thus cgroup_css() call in cgroup_add_file() returns NULL associating all cfents in the root cgroup with NULL css. This makes cgroup_file_open() trigger WARN and fail with -ENODEV for all !core subsystem files in the root cgroups. There's no reason to initialize cfent->css separately from cgroup_add_file(). As the association never changes, cgroup_file_open() can set it unconditionally every time and containing the logic in cgroup_file_open() makes more sense anyway as the only reason it's necessary is file->private_data being already occupied. Fix it by setting cfent->css unconditionally from cgroup_file_open(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1cb650b91ba582f6737457b7d22e368585596d2c |
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19-Aug-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: change cgroup_from_id() to css_from_id() Now we want cgroup core to always provide the css to use to the subsystems, so change this API to css_from_id(). Uninline css_from_id(), because it's getting bigger and cgroup_css() has been unexported. While at it, remove the #ifdef, and shuffle the order of the args. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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930913a31289202d232186b82854b26d7fb7cf4d |
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16-Aug-2013 |
Li Zhong <zhong@linux.vnet.ibm.com> |
cgroup: use css_get() in cgroup_create() to check CSS_ROOT It seems that the root css doesn't have refcnt allocated(not needed?), and would cause the booting error attached. This patch tries to use css_get() to not increase the refcnt if parent is root. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff810b37cc>] cgroup_mkdir+0x37c/0x740 PGD 0 Oops: 0002 [#1] Modules linked in: CPU: 0 PID: 1 Comm: systemd Not tainted 3.11.0-rc5-next-20130815+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007 task: ffff88007f868000 ti: ffff88007f864000 task.ti: ffff88007f864000 RIP: 0010:[<ffffffff810b37cc>] [<ffffffff810b37cc>] cgroup_mkdir+0x37c/0x740 RSP: 0018:ffff88007f865df8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffffff81a46ee0 RCX: 0000000000000001 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff81a415c0 RBP: ffff88007f865ec8 R08: 0000000000000001 R09: 0000000000000000 R10: ffff88007ce6d060 R11: 0000000000000000 R12: ffff88007ce6d000 R13: ffff88007ce6d060 R14: ffffffff81a46d80 R15: ffff88007c6e8018 FS: 00007f13dbf6f840(0000) GS:ffffffff81a23000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007b7e5000 CR4: 00000000000006b0 Stack: ffffffff810b380d 0000000000000002 ffff88007f865e18 ffffffff81167069 ffff88007f865ed8 ffffffff8116a3f5 ffff880037454400 ffff88007c6e8018 ffff88007c6e8028 ffff88007c6e8328 ffff88007c6e8000 ffff88007ce6d000 Call Trace: [<ffffffff810b380d>] ? cgroup_mkdir+0x3bd/0x740 [<ffffffff81167069>] ? lookup_hash+0x19/0x20 [<ffffffff8116a3f5>] ? kern_path_create+0x95/0x170 [<ffffffff8116ce3e>] vfs_mkdir+0x9e/0xf0 [<ffffffff8116d7a0>] SyS_mkdirat+0x60/0xe0 [<ffffffff8116d839>] SyS_mkdir+0x19/0x20 [<ffffffff814c960d>] tracesys+0xcf/0xd4 Code: ad 70 ff ff ff 48 89 9d 60 ff ff ff 4d 89 d5 4c 8b bd 68 ff ff ff 4c 8b 65 88 eb 50 0f 1f 00 48 8b 43 18 a8 03 0f 85 6c 03 00 00 <ff> 00 e8 1d 0a fb ff 85 c0 74 0d 80 3d f0 45 a1 00 00 0f 84 4c RIP [<ffffffff810b37cc>] cgroup_mkdir+0x37c/0x740 RSP <ffff88007f865df8> CR2: 0000000000000000 ---[ end trace a4b14b49bc46fd60 ]--- Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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0c21ead136a900c36f1ab74fd7d09a306dc31324 |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: RCU protect each cgroup_subsys_state release With the planned unified hierarchy, individual css's will be created and destroyed dynamically across the lifetime of a cgroup. To enable such usages, css destruction is being decoupled from cgroup destruction. Most of the destruction path has been decoupled but the actual free of css still depends on cgroup free path. When all css refs are drained, css_release() kicks off css_free_work_fn() which puts the cgroup. When the cgroup refcnt reaches zero, cgroup_diput() is invoked which in turn schedules RCU free of the cgroup. After a grace period, all css's are freed along with the cgroup itself. This patch moves the RCU grace period and css freeing from cgroup release path to css release path. css_release(), instead of kicking off css_free_work_fn() directly, schedules RCU callback css_free_rcu_fn() which in turn kicks off css_free_work_fn() after a RCU grace period. css_free_work_fn() is updated to free the css directly. The five-way punting - percpu ref kill confirmation, a work item, percpu ref release, RCU grace period, and again a work item - is quite hairy but the work items are there only to provide process context and the actual sequence is kill confirm -> release -> RCU free, which isn't simple but not too crazy. This removes cgroup_css() usage after offline_css() allowing clearing cgroup->subsys[] from offline_css(), which makes it consistent with online_css() and brings it closer to proper lifetime management for individual css's. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3c14f8b44fafaa60519440bea1591e495b928327 |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: move subsys file removal to kill_css() With the planned unified hierarchy, individual css's will be created and destroyed dynamically across the lifetime of a cgroup. To enable such usages, css destruction is being decoupled from cgroup destruction. This patch moves subsys file removal from cgroup_destroy_locked() to kill_css(). While this changes the order of destruction operations, the changes shouldn't be noticeable to cgroup subsystems or userland. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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edae0c3358947f8be5ca99f762d89e0c38e1f5d5 |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: factor out kill_css() Factor out css ref killing from cgroup_destroy_locked() into kill_css(). We're gonna add more to the path and the factored out function will eventually be called from other places too. While at it, replace open coded percpu_ref_get() with css_get() for consistency. This shouldn't cause any functional difference as the function is not used for root cgroups. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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09a503ea3a816b285b0b402b7f785eaec0c7a7e1 |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: decouple cgroup_subsys_state destruction from cgroup destruction Currently, css (cgroup_subsys_state) lifetime is tied to that of the associated cgroup. css's are created when the associated cgroup is created and destroyed when it gets destroyed. Also, individual css's aren't RCU protected but the whole cgroup is. With the planned unified hierarchy, css's will need to be dynamically created and destroyed within the lifetime of a cgroup. To enable such usages, this patch decouples css destruction from cgroup destruction - offline_css() invocation and the final css_put() are moved from cgroup_destroy_css_killed() to css_killed_work_fn(). Now each css is individually offlined and put as its reference count is killed instead of waiting for all css's attached to the cgroup to finish refcnt killing and then proceeding to offlining and putting them together. While this changes the order of destruction operations, the changes shouldn't be noticeable to cgroup subsystems or userland. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f20104de55a212a9742d8df1807f1f29dc95b748 |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: replace cgroup->css_kill_cnt with ->nr_css Currently, css (cgroup_subsys_state) lifetime is tied to that of the associated cgroup. With the planned unified hierarchy, css's will be dynamically created and destroyed within the lifetime of a cgroup. To enable such usages, css's will be individually RCU protected instead of being tied to the cgroup. cgroup->css_kill_cnt is used during cgroup destruction to wait for css reference count disable; however, this model doesn't work once css's lifetimes are managed separately from cgroup's. This patch replaces it with cgroup->nr_css which is an cgroup_mutex protected integer counting the number of attached css's. The count is incremented from online_css() and decremented after refcnt kill is confirmed. If the count reaches zero and the cgroup is marked dead, the second stage of cgroup destruction is kicked off. If a cgroup doesn't have any css attached at the time of rmdir, cgroup_destroy_locked() now invokes the second stage directly as no css kill confirmation would happen. cgroup_offline_fn() - the second step of cgroup destruction - is renamed to cgroup_destroy_css_killed() and now expects to be called with cgroup_mutex held. While this patch changes how css destruction is punted to work items, it shouldn't change any visible behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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223dbc38d2a8745a93749dc75ed909e274ce075d |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: bounce cgroup_subsys_state ref kill confirmation to a work item css (cgroup_subsys_state) offlining, which requires process context, will be moved to ref kill confirmation. In preparation, bounce css_killed handling through css->destroy_work. css_ref_killed_fn() is renamed to css_killed_ref_fn() so that it's consistent with the new css_killed_work_fn(). This patch adds an additional work item bouncing but doesn't change the actual logic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ae7f164a09408bf21ab3c82a9e80a3ff37aa9e3e |
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14-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup->subsys[] assignment to online_css() Currently, css (cgroup_subsys_state) lifetime is tied to that of the associated cgroup. With the planned unified hierarchy, css's will be dynamically created and destroyed within the lifetime of a cgroup. To enable such usages, css's will be individually RCU protected instead of being tied to the cgroup. In preparation, this patch moves cgroup->subsys[] assignment from init_css() to online_css(). As this means that a newly initialized css should be remembered separately and that cgroup_css() returns NULL between init and online, cgroup_create() is updated so that it stores newly created css's in a local array css_ar[] and cgroup_init/load_subsys() are updated to use local variable @css instead of using cgroup_css(). This change also slightly simplifies error path of cgroup_create(). While this patch changes when cgroup->subsys[] is initialized, this change isn't visible to subsystems or userland. v2: This patch wasn't updated accordingly after the previous "cgroup: reorganize css init / exit paths" was updated leading to missing a css_ar[] conversion in cgroup_create() and thus boot failure. Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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623f926b050e12b0f5e3a2f4d11c36e4ddd63541 |
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13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: reorganize css init / exit paths css (cgroup_subsys_state) lifetime management is about to be restructured. In prepartion, make the following mostly trivial changes. * init_cgroup_css() is renamed to init_css() so that it's consistent with other css handling functions. * alloc_css_id(), online_css() and offline_css() updated to take @css instead of cgroups and subsys IDs. This patch doesn't make any functional changes. v2: v1 merged two for_each_root_subsys() loops in cgroup_create() but Li Zefan pointed out that it breaks error path. Dropped. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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73e80ed8007fc48a6deeb295ba37159fad274bd2 |
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13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add __rcu modifier to cgroup->subsys[] For the planned unified hierarchy, each css (cgroup_subsys_state) will be RCU protected so that it can be created and destroyed individually while allowing RCU accesses. Previous changes ensured that all cgroup->subsys[] accesses use the cgroup_css() accessor. This patch adds __rcu modifier to cgroup->subsys[], add matching RCU dereference in cgroup_css() and convert all assignments to either rcu_assign_pointer() or RCU_INIT_POINTER(). This change prepares for the actual RCUfication of css's and doesn't introduce any visible behavior change. The conversion is verified with sparse and all accesses are properly RCU annotated. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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105347ba5da3e87facce2337c50cd5df93cc6bec |
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13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_file_open() rcu_read_lock() around cgroup_css() and add cfent->css For the planned unified hierarchy, each css (cgroup_subsys_state) will be RCU protected so that it can be created and destroyed individually while allowing RCU accesses, and cgroup_css() will soon require either holding cgroup_mutex or RCU read lock. This patch updates cgroup_file_open() such that it acquires the associated css under rcu_read_lock(). While cgroup_file_css() usages in other file operations are safe due to the reference from open, cgroup_css() wouldn't know that and will still trigger warnings. It'd be cleanest to store the acquired css in file->prvidate_data for further file operations but that's already used by seqfile. This patch instead adds cfent->css to cache the associated css. Note that while this field is initialized during cfe init, it should only be considered valid while the file is open. This patch doesn't change visible behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b77d7b6088377998ebf65eaea5e51008c2d75e94 |
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13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_css_from_dir() now should be called with RCU read locked cgroup->subsys[] will become RCU protected and thus all cgroup_css() usages should either be under RCU read lock or cgroup_mutex. This patch updates cgroup_css_from_dir() which returns the matching cgroup_subsys_state given a directory file and subsys_id so that it requires RCU read lock and updates its sole user perf_cgroup_connect(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com>
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0ae78e0bf10ac38ab53548e18383afc9997eca22 |
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13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup_subsys_state->parent With the planned unified hierarchy, css's (cgroup_subsys_state) will be RCU protected and allowed to be attached and detached dynamically over the course of a cgroup's lifetime. This means that css's will stay accessible after being detached from its cgroup - the matching pointer in cgroup->subsys[] cleared - for ref draining and RCU grace period. cgroup core still wants to guarantee that the parent css is never destroyed before its children and css_parent() always returns the parent regardless of the state of the child css as long as it's accessible. This patch makes css's hold onto their parents and adds css->parent so that the parent css is never detroyed before its children and can be determined without consulting the cgroups. cgroup->dummy_css is also updated to point to the parent dummy_css; however, it doesn't need to worry about object lifetime as the parent cgroup is already pinned by the child. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
|
35ef10da65d43211f4cd7e7822cbb3becdfc0ae1 |
|
13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_subsys_state->dput_work and its callback function css (cgroup_subsys_state) will become RCU protected and there will be two stages which require punting to work item during release. To prepare for using the work item for multiple times, rename css->dput_work to css->destroy_work and css_dput_fn() to css_free_work_fn() and move work item initialization from css init to right before the actual usage. This reorganization doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
|
40e93b39cd5b6a347333a95152ce37deef37bbd0 |
|
13-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: always use cgroup_css() cgroup_css() is the accessor for cgroup->subsys[] but is not used consistently. cgroup->subsys[] will become RCU protected and cgroup_css() will grow synchronization sanity checks. In preparation, make all cgroup->subsys[] dereferences use cgroup_css() consistently. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
|
bd8815a6d802fc16a7a106e170593aa05dc17e72 |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make css_for_each_descendant() and friends include the origin css in the iteration Previously, all css descendant iterators didn't include the origin (root of subtree) css in the iteration. The reasons were maintaining consistency with css_for_each_child() and that at the time of introduction more use cases needed skipping the origin anyway; however, given that css_is_descendant() considers self to be a descendant, omitting the origin css has become more confusing and looking at the accumulated use cases rather clearly indicates that including origin would result in simpler code overall. While this is a change which can easily lead to subtle bugs, cgroup API including the iterators has recently gone through major restructuring and no out-of-tree changes will be applicable without adjustments making this a relatively acceptable opportunity for this type of change. The conversions are mostly straight-forward. If the iteration block had explicit origin handling before or after, it's moved inside the iteration. If not, if (pos == origin) continue; is added. Some conversions add extra reference get/put around origin handling by consolidating origin handling and the rest. While the extra ref operations aren't strictly necessary, this shouldn't cause any noticeable difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
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95109b627ba6a043c181fa5fa45d1c754dd44fbc |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unexport cgroup_css() cgroup_css() no longer has any user left outside cgroup.c proper and we don't want subsystems to grow new usages of the function. cgroup core should always provide the css to use to the subsystems, which will make dynamic creation and destruction of css's across the lifetime of a cgroup much more manageable than exposing the cgroup directly to subsystems and let them dereference css's from it. Make cgroup_css() a static function in cgroup.c. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d99c8727e7bbc01b70e2c57e6127bfab26b868fd |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_taskset deal with cgroup_subsys_state instead of cgroup cgroup is in the process of converting to css (cgroup_subsys_state) from cgroup as the principal subsystem interface handle. This is mostly to prepare for the unified hierarchy support where css's will be created and destroyed dynamically but also helps cleaning up subsystem implementations as css is usually what they are interested in anyway. cgroup_taskset which is used by the subsystem attach methods is the last cgroup subsystem API which isn't using css as the handle. Update cgroup_taskset_cur_cgroup() to cgroup_taskset_cur_css() and cgroup_taskset_for_each() to take @skip_css instead of @skip_cgrp. The conversions are pretty mechanical. One exception is cpuset::cgroup_cs(), which lost its last user and got removed. This patch shouldn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org>
|
81eeaf0411204f52af8ef78ff107cfca2fcfec1d |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cftype->[un]register_event() deal with cgroup_subsys_state instead of cgroup cgroup is in the process of converting to css (cgroup_subsys_state) from cgroup as the principal subsystem interface handle. This is mostly to prepare for the unified hierarchy support where css's will be created and destroyed dynamically but also helps cleaning up subsystem implementations as css is usually what they are interested in anyway. cftype->[un]register_event() is among the remaining couple interfaces which still use struct cgroup. Convert it to cgroup_subsys_state. The conversion is mostly mechanical and removes the last users of mem_cgroup_from_cont() and cg_to_vmpressure(), which are removed. v2: indentation update as suggested by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
|
72ec7029937f0518eff21b8762743c31591684f5 |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make task iterators deal with cgroup_subsys_state instead of cgroup cgroup is in the process of converting to css (cgroup_subsys_state) from cgroup as the principal subsystem interface handle. This is mostly to prepare for the unified hierarchy support where css's will be created and destroyed dynamically but also helps cleaning up subsystem implementations as css is usually what they are interested in anyway. This patch converts task iterators to deal with css instead of cgroup. Note that under unified hierarchy, different sets of tasks will be considered belonging to a given cgroup depending on the subsystem in question and making the iterators deal with css instead cgroup provides them with enough information about the iteration. While at it, fix several function comment formats in cpuset.c. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Matt Helsley <matthltc@us.ibm.com>
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e535837b1dae17b5a2d76ea1bc22ac1a79354624 |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove struct cgroup_scanner cgroup_scan_tasks() takes a pointer to struct cgroup_scanner as its sole argument and the only function of that struct is packing the arguments of the function call which are consisted of five fields. It's not too unusual to pack parameters into a struct when the number of arguments gets excessive or the whole set needs to be passed around a lot, but neither holds here making it just weird. Drop struct cgroup_scanner and pass the params directly to cgroup_scan_tasks(). Note that struct cpuset_change_nodemask_arg was added to cpuset.c to pass both ->cs and ->newmems pointer to cpuset_change_nodemask() using single data pointer. This doesn't make any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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c59cd3d840b1b0a8f996cbbd9132128dcaabbeb9 |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_task_iter remember the cgroup being iterated Currently all cgroup_task_iter functions require @cgrp to be passed in, which is superflous and increases chance of usage error. Make cgroup_task_iter remember the cgroup being iterated and drop @cgrp argument from next and end functions. This patch doesn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
|
0942eeeef68f9493c1bcb1a52baf612b73fcf9fb |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: rename cgroup_iter to cgroup_task_iter cgroup now has multiple iterators and it's quite confusing to have something which walks over tasks of a single cgroup named cgroup_iter. Let's rename it to cgroup_task_iter. While at it, reformat / update comments and replace the overview comment above the interface function decls with proper function comments. Such overview can be useful but function comments should be more than enough here. This is pure rename and doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
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d515876e9d951d8cf7fc7c90db2967664bdc89ee |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate cgroup_advance_iter() For some reason, cgroup_advance_iter() is standing lonely all away from its iter comrades. Relocate it. This is cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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492eb21b98f88e411a8bb43d6edcd7d7022add10 |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make hierarchy iterators deal with cgroup_subsys_state instead of cgroup cgroup is currently in the process of transitioning to using css (cgroup_subsys_state) as the primary handle instead of cgroup in subsystem API. For hierarchy iterators, this is beneficial because * In most cases, css is the only thing subsystems care about anyway. * On the planned unified hierarchy, iterations for different subsystems will need to skip over different subtrees of the hierarchy depending on which subsystems are enabled on each cgroup. Passing around css makes it unnecessary to explicitly specify the subsystem in question as css is intersection between cgroup and subsystem * For the planned unified hierarchy, css's would need to be created and destroyed dynamically independent from cgroup hierarchy. Having cgroup core manage css iteration makes enforcing deref rules a lot easier. Most subsystem conversions are straight-forward. Noteworthy changes are * blkio: cgroup_to_blkcg() is no longer used. Removed. * freezer: cgroup_freezer() is no longer used. Removed. * devices: cgroup_to_devcgroup() is no longer used. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Aristeu Rozanski <aris@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Jens Axboe <axboe@kernel.dk>
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f48e3924dca268c677c4e338e5d91ad9e6fe6b9e |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: always use cgroup_next_child() to walk the children list There are several places where the children list is accessed directly. This patch converts those places to use cgroup_next_child(). This will help updating the hierarchy iterators to use @css instead of @cgrp. While cgroup_next_child() can be heavy in pathological cases - e.g. a lot of dead children, this shouldn't cause any noticeable behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3b287a505ef4024634beb12a93773254909d5dae |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: convert cgroup_next_sibling() to cgroup_next_child() cgroup is transitioning to using css (cgroup_subsys_state) as the main subsys interface handle instead of cgroup and the iterators will be updated to use css too. The iterators need to walk the cgroup hierarchy and return the css's matching the origin css, which is a bit cumbersome to open code. This patch converts cgroup_next_sibling() to cgroup_next_child() so that it can handle all steps of direct child iteration. This will be used to update iterators to take @css instead of @cgrp. In addition to the new iteration init handling, cgroup_next_child() is restructured so that the different branches share the end of iteration condition check. This patch doesn't change any behavior. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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182446d087906de40e514573a92a97b203695f71 |
|
09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: pass around cgroup_subsys_state instead of cgroup in file methods cgroup is currently in the process of transitioning to using struct cgroup_subsys_state * as the primary handle instead of struct cgroup. Please see the previous commit which converts the subsystem methods for rationale. This patch converts all cftype file operations to take @css instead of @cgroup. cftypes for the cgroup core files don't have their subsytem pointer set. These will automatically use the dummy_css added by the previous patch and can be converted the same way. Most subsystem conversions are straight forwards but there are some interesting ones. * freezer: update_if_frozen() is also converted to take @css instead of @cgroup for consistency. This will make the code look simpler too once iterators are converted to use css. * memory/vmpressure: mem_cgroup_from_css() needs to be exported to vmpressure while mem_cgroup_from_cont() can be made static. Updated accordingly. * cpu: cgroup_tg() doesn't have any user left. Removed. * cpuacct: cgroup_ca() doesn't have any user left. Removed. * hugetlb: hugetlb_cgroup_form_cgroup() doesn't have any user left. Removed. * net_cls: cgrp_cls_state() doesn't have any user left. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Steven Rostedt <rostedt@goodmis.org>
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67f4c36f83455b253445b2cb28ac9a2c4f85d99a |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup->dummy_css cgroup subsystem API is being converted to use css (cgroup_subsys_state) as the main handle, which makes things a bit awkward for subsystem agnostic core features - the "cgroup.*" interface files and various iterations - a bit awkward as they don't have a css to use. This patch adds cgroup->dummy_css which has NULL ->ss and whose only role is pointing back to the cgroup. This will be used to support subsystem agnostic features on the coming css based API. css_parent() is updated to handle dummy_css's. Note that css will soon grow its own ->parent field and css_parent() will be made trivial. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f7d58818ba4249f04a83b73aaac135640050bb4f |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: pin cgroup_subsys_state when opening a cgroupfs file Previously, each file read/write operation relied on the inode reference count pinning the cgroup and simply checked whether the cgroup was marked dead before proceeding to invoke the per-subsystem callback. This was rather silly as it didn't have any synchronization or css pinning around the check and the cgroup may be removed and all css refs drained between the DEAD check and actual method invocation. This patch pins the css between open() and release() so that it is guaranteed to be alive for all file operations and remove the silly DEAD checks from cgroup_file_read/write(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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2bb566cb68dfafad328af666ebadf0e49accd6ca |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add subsys backlink pointer to cftype cgroup is transitioning to using css (cgroup_subsys_state) instead of cgroup as the primary subsystem handle. The cgroupfs file interface will be converted to use css's which requires finding out the subsystem from cftype so that the matching css can be determined from the cgroup. This patch adds cftype->ss which points to the subsystem the file belongs to. The field is initialized while a cftype is being registered. This makes it unnecessary to explicitly specify the subsystem for other cftype handling functions. @ss argument dropped from various cftype handling functions. This patch shouldn't introduce any behavior differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk>
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eb95419b023abacb415e2a18fea899023ce7624d |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: pass around cgroup_subsys_state instead of cgroup in subsystem methods cgroup is currently in the process of transitioning to using struct cgroup_subsys_state * as the primary handle instead of struct cgroup * in subsystem implementations for the following reasons. * With unified hierarchy, subsystems will be dynamically bound and unbound from cgroups and thus css's (cgroup_subsys_state) may be created and destroyed dynamically over the lifetime of a cgroup, which is different from the current state where all css's are allocated and destroyed together with the associated cgroup. This in turn means that cgroup_css() should be synchronized and may return NULL, making it more cumbersome to use. * Differing levels of per-subsystem granularity in the unified hierarchy means that the task and descendant iterators should behave differently depending on the specific subsystem the iteration is being performed for. * In majority of the cases, subsystems only care about its part in the cgroup hierarchy - ie. the hierarchy of css's. Subsystem methods often obtain the matching css pointer from the cgroup and don't bother with the cgroup pointer itself. Passing around css fits much better. This patch converts all cgroup_subsys methods to take @css instead of @cgroup. The conversions are mostly straight-forward. A few noteworthy changes are * ->css_alloc() now takes css of the parent cgroup rather than the pointer to the new cgroup as the css for the new cgroup doesn't exist yet. Knowing the parent css is enough for all the existing subsystems. * In kernel/cgroup.c::offline_css(), unnecessary open coded css dereference is replaced with local variable access. This patch shouldn't cause any behavior differences. v2: Unnecessary explicit cgrp->subsys[] deref in css_online() replaced with local variable @css as suggested by Li Zefan. Rebased on top of new for-3.12 which includes for-3.11-fixes so that ->css_free() invocation added by da0a12caff ("cgroup: fix a leak when percpu_ref_init() fails") is converted too. Suggested by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Aristeu Rozanski <aris@redhat.com> Acked-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Steven Rostedt <rostedt@goodmis.org>
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72c97e54e0f043d33b246d7460ae0a36c4b8c643 |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add subsystem pointer to cgroup_subsys_state Currently, given a cgroup_subsys_state, there's no way to find out which subsystem the css is for, which we'll need to convert the cgroup controller API to primarily use @css instead of @cgroup. This patch adds cgroup_subsys_state->ss which points to the subsystem the @css belongs to. While at it, remove the comment about accessing @css->cgroup to determine the hierarchy. cgroup core will provide API to traverse hierarchy of css'es and we don't want subsystems to directly walk cgroup hierarchies anymore. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8af01f56a03e9cbd91a55d688fce1315021efba8 |
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09-Aug-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: s/cgroup_subsys_state/cgroup_css/ s/task_subsys_state/task_css/ The names of the two struct cgroup_subsys_state accessors - cgroup_subsys_state() and task_subsys_state() - are somewhat awkward. The former clashes with the type name and the latter doesn't even indicate it's somehow related to cgroup. We're about to revamp large portion of cgroup API, so, let's rename them so that they're less awkward. Most per-controller usages of the accessors are localized in accessor wrappers and given the amount of scheduled changes, this isn't gonna add any noticeable headache. Rename cgroup_subsys_state() to cgroup_css() and task_subsys_state() to task_css(). This patch is pure rename. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b395890a092d8ecbe54f005179e3dec4b6bf752a |
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01-Aug-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: rename cgroup_pidlist->mutex It's a rw_semaphore not a mutex. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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876ede8b2b9880615be0de3ec7b8afd0a1786e76 |
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01-Aug-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: restructure the failure path in cgroup_write_event_control() It uses a single label and checks the validity of each pointer. This is err-prone, and actually we had a bug because one of the check was insufficient. Use multi lables as we do in other places. v2: - drop initializations of local variables. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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4e96ee8e981b5140a2bcc5fff0d5c0eef39a62ee |
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31-Jul-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: convert cgroup_ida to cgroup_idr This enables us to lookup a cgroup by its id. v4: - add a comment for idr_remove() in cgroup_offline_fn(). v3: - on success, idr_alloc() returns the id but not 0, so fix the BUG_ON() in cgroup_init(). - pass the right value to idr_alloc() so that the id for dummy cgroup is 0. Signed-off-by: Li Zefan <lizefan@huawei.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org>
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6f4b7e632d78c2d91502211c430722cc66428492 |
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31-Jul-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: more naming cleanups Constantly use @cset for css_set variables and use @cgrp as cgroup variables. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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e0798ce27346edb8aa369b5b39af5a47fdf2b25c |
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31-Jul-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove struct cgroup_seqfile_state We can use struct cfent instead. v2: - remove cgroup_seqfile_release(). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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2a4ac63333584b2791986cf2270f5ba9a4b97606 |
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31-Jul-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove sparse tags from offline_css() This should have been removed in commit d7eeac1913ff ("cgroup: hold cgroup_mutex before calling css_offline"). While at it, update the comments. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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da0a12caffad2eeadea429f83818408e7b77379a |
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31-Jul-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix a leak when percpu_ref_init() fails ss->css_free() is not called when perfcpu_ref_init() fails. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a698b4488ab98deef6c3beeba3e27fea17650132 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove gratuituous BUG_ON()s from rebind_subsystems() rebind_subsystems() performs santiy checks even on subsystems which aren't specified to be added or removed and the checks aren't all that useful given that these are in a very cold path while the violations they check would trip up in much hotter paths. Let's remove these from rebind_subsystems(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1d5be6b287c8efc879fbe578e2b7bc8f7a38f313 |
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12-Jul-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: move module ref handling into rebind_subsystems() Module ref handling in cgroup is rather weird. parse_cgroupfs_options() grabs all the modules for the specified subsystems. A module ref is kept if the specified subsystem is newly bound to the hierarchy. If not, or the operation fails, the refs are dropped. This scatters module ref handling across multiple functions making it difficult to track. It also make the function nasty to use for dynamic subsystem binding which is necessary for the planned unified hierarchy. There's nothing which requires the subsystem modules to be pinned between parse_cgroupfs_options() and rebind_subsystems() in both mount and remount paths. parse_cgroupfs_options() can just parse and rebind_subsystems() can handle pinning the subsystems that it wants to bind, which is a natural part of its task - binding - anyway. Move module ref handling into rebind_subsystems() which makes the code a lot simpler - modules are gotten iff it's gonna be bound and put iff unbound or binding fails. v2: Li pointed out that if a controller module is unloaded between parsing and binding, rebind_subsystems() won't notice the missing controller as it only iterates through existing controllers. Fix it by updating rebind_subsystems() to compare @added_mask to @pinned and fail with -ENOENT if they don't match. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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786e1448d9c5d2a469bcc9d2aecacd418ee1aca0 |
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14-Jul-2013 |
Al Viro <viro@zeniv.linux.org.uk> |
cgroup: we can use simple_lookup() now Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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913ffdb54366f94eec65c656cae8c6e00e1ab1b0 |
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12-Jul-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path() task_cgroup_path_from_hierarchy() was added for the planned new users and none of the currently planned users wants to know about multiple hierarchies. This patch drops the multiple hierarchy part and makes it always return the path in the first non-dummy hierarchy. As unified hierarchy will always have id 1, this is guaranteed to return the path for the unified hierarchy if mounted; otherwise, it will return the path from the hierarchy which happens to occupy the lowest hierarchy id, which will usually be the first hierarchy mounted after boot. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Lennart Poettering <lennart@poettering.net> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Jan Kaluža <jkaluza@redhat.com>
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f172e67cf9d842bc646d0f66792e38435a334b1e |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: move number_of_cgroups test out of rebind_subsystems() into cgroup_remount() rebind_subsystems() currently fails if the hierarchy has any !root cgroups; however, on the planned unified hierarchy, rebind_subsystems() will be used while populated. Move the test to cgroup_remount(), which is the only place the test is necessary anyway. As it's impossible for the other two callers of rebind_subsystems() to have populated hierarchy, this doesn't make any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3126121fb30941552b1a806c7c2e686bde57e270 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make rebind_subsystems() handle file additions and removals with proper error handling Currently, creating and removing cgroup files in the root directory are handled separately from the actual subsystem binding and unbinding which happens in rebind_subsystems(). Also, rebind_subsystems() users aren't handling file creation errors properly. Let's integrate top_cgroup file handling into rebind_subsystems() so that it's simpler to use and everyone handles file creation errors correctly. * On a successful return, rebind_subsystems() is guaranteed to have created all files of the new subsystems and deleted the ones belonging to the removed subsystems. After a failure, no file is created or removed. * cgroup_remount() no longer needs to make explicit populate/clear calls as it's all handled by rebind_subsystems(), and it gets proper error handling automatically. * cgroup_mount() has been updated such that the root dentry and cgroup are linked before rebind_subsystems(). Also, the init_cred dancing and base file handling are moved right above rebind_subsystems() call and proper error handling for the base files is added. While at it, add a comment explaining what's going on with the cred thing. * cgroup_kill_sb() calls rebind_subsystems() to unbind all subsystems which now implies removing all subsystem files which requires the directory's i_mutex. Grab it. This means that files on the root cgroup are removed earlier - they used to be deleted from generic super_block cleanup from vfs. This doesn't lead to any functional difference and it's cleaner to do the clean up explicitly for all files. Combined with the previous changes, this makes all cgroup file creation errors handled correctly. v2: Added comment on init_cred. v3: Li spotted that cgroup_mount() wasn't freeing tmp_links after base file addition failure. Fix it by adding free_tmp_links error handling label. v4: v3 introduced build bugs which got noticed by Fengguang's awesome kbuild test robot. Fixed, and shame on me. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Fengguang Wu <fengguang.wu@intel.com>
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b420ba7db15659253d4f286a0ba479d336371999 |
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12-Jul-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: use for_each_subsys() instead of for_each_root_subsys() in cgroup_populate/clear_dir() rebind_subsystems() will be updated to handle file creations and removals with proper error handling and to do that will need to perform file operations before actually adding the subsystem to the hierarchy. To enable such usage, update cgroup_populate/clear_dir() to use for_each_subsys() instead of for_each_root_subsys() so that they operate on all subsystems specified by @subsys_mask whether that subsystem is currently bound to the hierarchy or not. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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bee550994f6b0c1179bd3ccea58dc5c2c4ccf842 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: update error handling in cgroup_populate_dir() cgroup_populate_dir() didn't use to check whether the actual file creations were successful and could return success with only subset of the requested files created, which is nasty. This patch udpates cgroup_populate_dir() so that it either succeeds with all files or fails with no file. v2: The original patch also converted for_each_root_subsys() usages to for_each_subsys() without explaining why. That part has been moved to a separate patch. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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628f7cd47ab758cae0353d1a6decf3d1459dca24 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: separate out cgroup_base_files[] handling out of cgroup_populate/clear_dir() cgroup_populate/clear_dir() currently take @base_files and adds and removes, respectively, cgroup_base_files[] to the directory. File additions and removals are being reorganized for proper error handling and more dynamic handling for the unified hierarchy, and mixing base and subsys file handling into the same functions gets a bit confusing. This patch moves base file handling out of cgroup_populate/clear_dir() into their users - cgroup_mount(), cgroup_create() and cgroup_destroy_locked(). Note that this changes the behavior of base file removal. If @base_files is %true, cgroup_clear_dir() used to delete files regardless of cftype until there's no files left. Now, only files with matching cfts are removed. As files can only be created by the base or registered cftypes, this shouldn't result in any behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9ccece80ae19ed42439fc0ced76858f189cd41e8 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup_add_cftypes() error handling cgroup_add_cftypes() uses cgroup_cfts_commit() to actually create the files; however, both functions ignore actual file creation errors and just assume success. This can lead to, for example, blkio hierarchy with some of the cgroups with only subset of interface files populated after cfq-iosched is loaded under heavy memory pressure, which is nasty. This patch updates cgroup_cfts_commit() and cgroup_add_cftypes() to guarantee that all files are created on success and no file is created on failure. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b1f28d3109349899e87377e89f9d8ab5bc95ec57 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix error path of cgroup_addrm_files() cgroup_addrm_files() mishandled error return value from cgroup_add_file() and returns error iff the last file fails to create. As we're in the process of cleaning up file add/rm error handling and will reliably propagate file creation failures, there's no point in keeping adding files after a failure. Replace the broken error collection logic with immediate error return. While at it, add lockdep assertions and function comment. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8f89140ae41ccd9c63344e6823faa862aa7435e3 |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: minor updates around cgroup_clear_directory() * Rename it to cgroup_clear_dir() and make it take the pointer to the target cgroup instead of the the dentry. This makes the function consistent with its counterpart - cgroup_populate_dir(). * Move cgroup_clear_directory() invocation from cgroup_d_remove_dir() to cgroup_remount() so that the function doesn't have to determine the cgroup pointer back from the dentry. cgroup_d_remove_dir() now only deals with vfs, which is slightly cleaner. This patch doesn't introduce any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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c7ba8287cd11f2fc9e2feee9e1fac34b7293658f |
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29-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: CGRP_ROOT_SUBSYS_BOUND should also be ignored when mounting an existing hierarchy 0ce6cba357 ("cgroup: CGRP_ROOT_SUBSYS_BOUND should be ignored when comparing mount options") only updated the remount path but CGRP_ROOT_SUBSYS_BOUND should also be ignored when comparing options while mounting an existing hierarchy. As option mismatch triggers a warning but doesn't fail the mount without sane_behavior, this only triggers a spurious warning message. Fix it by only comparing CGRP_ROOT_OPTION_MASK bits when comparing new and existing root options. Signed-off-by: Tejun Heo <tj@kernel.org>
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0ce6cba35777cf96a54ce0d5856dc962566b8717 |
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28-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: CGRP_ROOT_SUBSYS_BOUND should be ignored when comparing mount options 1672d04070 ("cgroup: fix cgroupfs_root early destruction path") introduced CGRP_ROOT_SUBSYS_BOUND which is used to mark completion of subsys binding on a new root; however, this broke remounts. cgroup_remount() doesn't allow changing root options via remount and CGRP_ROOT_SUBSYS_BOUND, which is set on all fully initialized roots, makes the function reject all remounts. Fix it by putting the options part in the lower 16 bits of root->flags and masking the comparions. While at it, make cgroup_remount() emit an error message explaining why it's rejecting a remount request, so that it's less of a mystery. Signed-off-by: Tejun Heo <tj@kernel.org>
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e2bd416f6246d11be29999c177d2534943a5c2df |
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28-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix deadlock on cgroup_mutex via drop_parsed_module_refcounts() eb178d06332 ("cgroup: grab cgroup_mutex in drop_parsed_module_refcounts()") made drop_parsed_module_refcounts() grab cgroup_mutex to make lockdep assertion in for_each_subsys() happy. Unfortunately, cgroup_remount() calls the function while holding cgroup_mutex in its failure path leading to the following deadlock. # mount -t cgroup -o remount,memory,blkio cgroup blkio cgroup: option changes via remount are deprecated (pid=525 comm=mount) ============================================= [ INFO: possible recursive locking detected ] 3.10.0-rc4-work+ #1 Not tainted --------------------------------------------- mount/525 is trying to acquire lock: (cgroup_mutex){+.+.+.}, at: [<ffffffff8110a3e1>] drop_parsed_module_refcounts+0x21/0xb0 but task is already holding lock: (cgroup_mutex){+.+.+.}, at: [<ffffffff8110e4e1>] cgroup_remount+0x51/0x200 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(cgroup_mutex); lock(cgroup_mutex); *** DEADLOCK *** May be due to missing lock nesting notation 4 locks held by mount/525: #0: (&type->s_umount_key#30){+.+...}, at: [<ffffffff811e9a0d>] do_mount+0x2bd/0xa30 #1: (&sb->s_type->i_mutex_key#9){+.+.+.}, at: [<ffffffff8110e4d3>] cgroup_remount+0x43/0x200 #2: (cgroup_mutex){+.+.+.}, at: [<ffffffff8110e4e1>] cgroup_remount+0x51/0x200 #3: (cgroup_root_mutex){+.+.+.}, at: [<ffffffff8110e4ef>] cgroup_remount+0x5f/0x200 stack backtrace: CPU: 2 PID: 525 Comm: mount Not tainted 3.10.0-rc4-work+ #1 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 ffffffff829651f0 ffff88000ec2fc28 ffffffff81c24bb1 ffff88000ec2fce8 ffffffff810f420d 0000000000000006 0000000000000001 0000000000000056 ffff8800153b4640 ffff880000000000 ffffffff81c2e468 ffff8800153b4640 Call Trace: [<ffffffff81c24bb1>] dump_stack+0x19/0x1b [<ffffffff810f420d>] __lock_acquire+0x15dd/0x1e60 [<ffffffff810f531c>] lock_acquire+0x9c/0x1f0 [<ffffffff81c2a805>] mutex_lock_nested+0x65/0x410 [<ffffffff8110a3e1>] drop_parsed_module_refcounts+0x21/0xb0 [<ffffffff8110e63e>] cgroup_remount+0x1ae/0x200 [<ffffffff811c9bb2>] do_remount_sb+0x82/0x190 [<ffffffff811e9d41>] do_mount+0x5f1/0xa30 [<ffffffff811ea203>] SyS_mount+0x83/0xc0 [<ffffffff81c2fb82>] system_call_fastpath+0x16/0x1b Fix it by moving the drop_parsed_module_refcounts() invocation outside cgroup_mutex. Signed-off-by: Tejun Heo <tj@kernel.org>
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a4ea1cc90604df08d471ae84eb9627319d10c844 |
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22-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: always use RCU accessors for protected accesses kernel/cgroup.c still has places where a RCU pointer is set and accessed directly without going through RCU_INIT_POINTER() or rcu_dereference_protected(). They're all properly protected accesses so nothing is broken but it leads to spurious sparse RCU address space warnings. Substitute direct accesses with RCU_INIT_POINTER() and rcu_dereference_protected(). Note that %true is specified as the extra condition for all derference updates. This isn't ideal as all it does is suppressing warning without actually policing synchronization rules; however, most are scheduled to be removed pretty soon along with css_id itself, so no reason to be more elaborate. Combined with the previous changes, this removes all RCU related sparse warnings from cgroup. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by; Li Zefan <lizefan@huawei.com>
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a8ad805cfde00be8fe3b3dae8890996dbeb91e2c |
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22-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix RCU accesses around task->cgroups There are several places in kernel/cgroup.c where task->cgroups is accessed and modified without going through proper RCU accessors. None is broken as they're all lock protected accesses; however, this still triggers sparse RCU address space warnings. * Consistently use task_css_set() for task->cgroups dereferencing. * Use RCU_INIT_POINTER() to clear task->cgroups to &init_css_set on exit. * Remove unnecessary rcu_dereference_raw() from cset->subsys[] dereference in cgroup_exit(). Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Li Zefan <lizefan@huawei.com>
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eb178d063324d9c30f673db3877b892a48ade21e |
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26-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: grab cgroup_mutex in drop_parsed_module_refcounts() This isn't strictly necessary as all subsystems specified in @subsys_mask are guaranteed to be pinned; however, it does spuriously trigger lockdep warning. Let's grab cgroup_mutex around it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1672d040709b789671c0502e7aac9d632c2f9175 |
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26-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroupfs_root early destruction path cgroupfs_root used to have ->actual_subsys_mask in addition to ->subsys_mask. a8a648c4ac ("cgroup: remove cgroup->actual_subsys_mask") removed it noting that the subsys_mask is essentially temporary and doesn't belong in cgroupfs_root; however, the patch made it impossible to tell whether a cgroupfs_root actually has the subsystems bound or just have the bits set leading to the following BUG when trying to mount with subsystems which are already mounted elsewhere. kernel BUG at kernel/cgroup.c:1038! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC ... CPU: 1 PID: 7973 Comm: mount Tainted: G W 3.10.0-rc7-next-20130625-sasha-00011-g1c1dc0e #1105 task: ffff880fc0ae8000 ti: ffff880fc0b9a000 task.ti: ffff880fc0b9a000 RIP: 0010:[<ffffffff81249b29>] [<ffffffff81249b29>] rebind_subsystems+0x409/0x5f0 ... Call Trace: [<ffffffff8124bd4f>] cgroup_kill_sb+0xff/0x210 [<ffffffff813d21af>] deactivate_locked_super+0x4f/0x90 [<ffffffff8124f3b3>] cgroup_mount+0x673/0x6e0 [<ffffffff81257169>] cpuset_mount+0xd9/0x110 [<ffffffff813d2580>] mount_fs+0xb0/0x2d0 [<ffffffff81404afd>] vfs_kern_mount+0xbd/0x180 [<ffffffff814070b5>] do_new_mount+0x145/0x2c0 [<ffffffff814085d6>] do_mount+0x356/0x3c0 [<ffffffff8140873d>] SyS_mount+0xfd/0x140 [<ffffffff854eb600>] tracesys+0xdd/0xe2 We still want rebind_subsystems() to take added/removed masks, so let's fix it by marking whether a cgroupfs_root has finished binding or not. Also, document what's going on around ->subsys_mask initialization so that similar mistakes aren't repeated. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Sasha Levin <sasha.levin@oracle.com> Acked-by: Li Zefan <lizefan@huawei.com>
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fc76df706123602214da494ba98bccea83e2cfff |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: reserve ID 0 for dummy_root and 1 for unified hierarchy Before 1a57423166 ("cgroup: make hierarchy_id use cyclic idr"), hierarchy IDs were allocated from 0. As the dummy hierarchy was always the one first initialized, it got assigned 0 and all other hierarchies from 1. The patch accidentally changed the minimum useable ID to 2. Let's restore ID 0 for dummy_root and while at it reserve 1 for unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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30159ec7a9db7f3c91e2b27e66389c49302efd5c |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement for_each_[builtin_]subsys() There are quite a few places where all loaded [builtin] subsys are iterated. Implement for_each_[builtin_]subsys() and replace manual iterations with those to simplify those places a bit. The new iterators automatically skip NULL subsystems. This shouldn't cause any functional difference. Iteration loops which scan all subsystems and then skipping modular ones explicitly are converted to use for_each_builtin_subsys(). While at it, reorder variable declarations and adjust whitespaces a bit in the affected functions. v2: Add lockdep_assert_held() in for_each_subsys() and add comments about synchronization as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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82fe9b0da0d50e2795a49c268676fd132cbc3eea |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: move init_css_set initialization inside cgroup_mutex cgroup_init() was doing init_css_set initialization outside cgroup_mutex, which is fine but we want to add lockdep annotation on subsystem iterations and cgroup_init() will trigger it spuriously. Move init_css_set initialization inside cgroup_mutex. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5549c497913ad860d3dff4386c6423268bb85693 |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: s/for_each_subsys()/for_each_root_subsys()/ for_each_subsys() walks over subsystems attached to a hierarchy and we're gonna add iterators which walk over all available subsystems. Rename for_each_subsys() to for_each_root_subsys() so that it's more appropriately named and for_each_subsys() can be used to iterate all subsystems. While at it, remove unnecessary underbar prefix from macro arguments, put them inside parentheses, and adjust indentation for the two for_each_*() macros. This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b326f9d0dbd066b0aafbe88e6011a680a36de6e8 |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: clean up find_css_set() and friends find_css_set() passes uninitialized on-stack template[] array to find_existing_css_set() which sets the entries for all subsystems. Passing around an uninitialized array is a bit icky and we want to introduce an iterator which only iterates loaded subsystems. Let's initialize it on definition. While at it, also make the following cosmetic cleanups. * Convert to proper /** comments. * Reorder variable declarations. * Replace comment on synchronization with lockdep_assert_held(). This patch doesn't make any functional differences. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a8a648c4acee2095262f7fa65b0d8a68a03c32e4 |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup->actual_subsys_mask cgroup curiously has two subsystem masks, ->subsys_mask and ->actual_subsys_mask. The latter only exists because the new target subsys_mask is passed into rebind_subsystems() via @root>subsys_mask. rebind_subsystems() needs to know what the current mask is to decide how to reach the target mask so ->actual_subsys_mask is used as the temp location to remember the current state. Adding a temporary field to a permanent data structure is rather silly and can be misleading. Update rebind_subsystems() to take @added_mask and @removed_mask instead and remove @root->actual_subsys_mask. This patch shouldn't introduce any behavior changes. v2: Comment and description updated as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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9871bf9550d25e488cd2f0ce958d3f59f17fa720 |
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25-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: prefix global variables with "cgroup_" Global variable names in kernel/cgroup.c are asking for trouble - subsys, roots, rootnode and so on. Rename them to have "cgroup_" prefix. * s/subsys/cgroup_subsys/ * s/rootnode/cgroup_dummy_root/ * s/dummytop/cgroup_cummy_top/ * s/roots/cgroup_roots/ * s/root_count/cgroup_root_count/ This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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03c78cbebb323fc97295ff97dc5e009d56371d57 |
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14-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: rename cont to cgrp Cont is short for container. control group was named process container at first, but then people found container already has a meaning in linux kernel. Clean up the leftover variable name @cont. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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00356bd5f0f5e04183fb15805eb29e97c2fc20ac |
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18-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: clean up cgroup_serial_nr_cursor cgroup_serial_nr_cursor was created atomic64_t because I thought it was never gonna used for anything other than assigning unique numbers to cgroups and didn't want to worry about synchronization; however, now we're using it as an event-stamp to distinguish cgroups created before and after certain point which assumes that it's protected by cgroup_mutex. Let's make it clear by making it a u64. Also, rename it to cgroup_serial_nr_next and make it point to the next nr to allocate so that where it's pointing to is clear and more conventional. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com>
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e8c82d20a9f729cf4b9f73043f7fd4e0872bebfd |
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18-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: convert cgroup_cft_commit() to use cgroup_for_each_descendant_pre() We used root->allcg_list to iterate cgroup hierarchy because at that time cgroup_for_each_descendant_pre() hasn't been invented. tj: In cgroup_cfts_commit(), s/@serial_nr/@update_upto/, move the assignment right above releasing cgroup_mutex and explain what's going on there. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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794611a1dfcb055d7d41ce133378dd8197d73e38 |
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18-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: make serial_nr_cursor available throughout cgroup.c The next patch will use it to determine if a cgroup is newly created while we're iterating the cgroup hierarchy. tj: Rephrased the comment on top of cgroup_serial_nr_cursor. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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f57947d27711451a7739a25bba6cddc8a385e438 |
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18-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix memory leak in cgroup_rm_cftypes() The memory allocated in cgroup_add_cftypes() should be freed. The effect of this bug is we leak a bit memory everytime we unload cfq-iosched module if blkio cgroup is enabled. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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1c8158eeae0f37d0eee9f1fbe68080df6a408df2 |
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18-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix umount vs cgroup_event_remove() race commit 5db9a4d99b0157a513944e9a44d29c9cec2e91dc Author: Tejun Heo <tj@kernel.org> Date: Sat Jul 7 16:08:18 2012 -0700 cgroup: fix cgroup hierarchy umount race This commit fixed a race caused by the dput() in css_dput_fn(), but the dput() in cgroup_event_remove() can also lead to the same BUG(). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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084457f284abf6789d90509ee11dae383842b23b |
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18-Jun-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix umount vs cgroup_cfts_commit() race cgroup_cfts_commit() uses dget() to keep cgroup alive after cgroup_mutex is dropped, but dget() won't prevent cgroupfs from being umounted. When the race happens, vfs will see some dentries with non-zero refcnt while umount is in process. Keep running this: mount -t cgroup -o blkio xxx /cgroup umount /cgroup And this: modprobe cfq-iosched rmmod cfs-iosched After a while, the BUG() in shrink_dcache_for_umount_subtree() may be triggered: BUG: Dentry xxx{i=0,n=blkio.yyy} still in use (1) [umount of cgroup cgroup] Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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6db8e85c5c1f89cd0183b76dab027c81009f129f |
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14-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: disallow rename(2) if sane_behavior cgroup's rename(2) isn't a proper migration implementation - it can't move the cgroup to a different parent in the hierarchy. All it can do is swapping the name string for that cgroup. This isn't useful and can mislead users to think that cgroup supports proper cgroup-level migration. Disallow rename(2) if sane_behavior. v2: Fail with -EPERM instead of -EINVAL so that it matches the vfs return value when ->rename is not implemented as suggested by Li. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d3daf28da16a30af95bfb303189a634a87606725 |
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14-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: use percpu refcnt for cgroup_subsys_states A css (cgroup_subsys_state) is how each cgroup is represented to a controller. As such, it can be used in hot paths across the various subsystems different controllers are associated with. One of the common operations is reference counting, which up until now has been implemented using a global atomic counter and can have significant adverse impact on scalability. For example, css refcnt can be gotten and put multiple times by blkcg for each IO request. For highops configurations which try to do as much per-cpu as possible, the global frequent refcnting can be very expensive. In general, given the various and hugely diverse paths css's end up being used from, we need to make it cheap and highly scalable. In its usage, css refcnting isn't very different from module refcnting. This patch converts css refcnting to use the recently added percpu_ref. css_get/tryget/put() directly maps to the matching percpu_ref operations and the deactivation logic is no longer necessary as percpu_ref already has refcnt killing. The only complication is that as the refcnt is per-cpu, percpu_ref_kill() in itself doesn't ensure that further tryget operations will fail, which we need to guarantee before invoking ->css_offline()'s. This is resolved collecting kill confirmation using percpu_ref_kill_and_confirm() and initiating the offline phase of destruction after all css refcnt's are confirmed to be seen as killed on all CPUs. The previous patches already splitted destruction into two phases, so percpu_ref_kill_and_confirm() can be hooked up easily. This patch removes css_refcnt() which is used for rcu dereference sanity check in css_id(). While we can add a percpu refcnt API to ask the same question, css_id() itself is scheduled to be removed fairly soon, so let's not bother with it. Just drop the sanity check and use rcu_dereference_raw() instead. v2: - init_cgroup_css() was calling percpu_ref_init() without checking the return value. This causes two problems - the obvious lack of error handling and percpu_ref_init() being called from cgroup_init_subsys() before the allocators are up, which triggers warnings but doesn't cause actual problems as the refcnt isn't used for roots anyway. Fix both by moving percpu_ref_init() to cgroup_create(). - The base references were put too early by percpu_ref_kill_and_confirm() and cgroup_offline_fn() put the refs one extra time. This wasn't noticeable because css's go through another RCU grace period before being freed. Update cgroup_destroy_locked() to grab an extra reference before killing the refcnts. This problem was noticed by Kent. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Kent Overstreet <koverstreet@google.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: "Alasdair G. Kergon" <agk@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Glauber Costa <glommer@gmail.com>
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ea15f8ccdb430af1e8bc9b4e19a230eb4c356777 |
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14-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: split cgroup destruction into two steps Split cgroup_destroy_locked() into two steps and put the latter half into cgroup_offline_fn() which is executed from a work item. The latter half is responsible for offlining the css's, removing the cgroup from internal lists, and propagating release notification to the parent. The separation is to allow using percpu refcnt for css. Note that this allows for other cgroup operations to happen between the first and second halves of destruction, including creating a new cgroup with the same name. As the target cgroup is marked DEAD in the first half and cgroup internals don't care about the names of cgroups, this should be fine. A comment explaining this will be added by the next patch which implements the actual percpu refcnting. As RCU freeing is guaranteed to happen after the second step of destruction, we can use the same work item for both. This patch renames cgroup->free_work to ->destroy_work and uses it for both purposes. INIT_WORK() is now performed right before queueing the work item. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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455050d23e1bfc47ca98e943ad5b2f3a9bbe45fb |
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14-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: reorder the operations in cgroup_destroy_locked() This patch reorders the operations in cgroup_destroy_locked() such that the userland visible parts happen before css offlining and removal from the ->sibling list. This will be used to make css use percpu refcnt. While at it, split out CGRP_DEAD related comment from the refcnt deactivation one and correct / clarify how different guarantees are met. While this patch changes the specific order of operations, it shouldn't cause any noticeable behavior difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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6f3d828f0fb7fdaffc6f32cb8a1cb7fcf8824598 |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup->count and use cgroup->count tracks the number of css_sets associated with the cgroup and used only to verify that no css_set is associated when the cgroup is being destroyed. It's superflous as the destruction path can simply check whether cgroup->cset_links is empty instead. Drop cgroup->count and check ->cset_links directly from cgroup_destroy_locked(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ddd69148bdc45e5e3e55bfde3571daecd5a96d75 |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: drop unnecessary RCU dancing from __put_css_set() __put_css_set() does RCU read access on @cgrp across dropping @cgrp->count so that it can continue accessing @cgrp even if the count reached zero and destruction of the cgroup commenced. Given that both sides - __css_put() and cgroup_destroy_locked() - are cold paths, this is unnecessary. Just making cgroup_destroy_locked() grab css_set_lock while checking @cgrp->count is enough. Remove the RCU read locking from __put_css_set() and make cgroup_destroy_locked() read-lock css_set_lock when checking @cgrp->count. This will also allow removing @cgrp->count. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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54766d4a1d3d6f84ff8fa475cd8f165c0a0000eb |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: rename CGRP_REMOVED to CGRP_DEAD We will add another flag indicating that the cgroup is in the process of being killed. REMOVING / REMOVED is more difficult to distinguish and cgroup_is_removing()/cgroup_is_removed() are a bit awkward. Also, later percpu_ref usage will involve "kill"ing the refcnt. s/CGRP_REMOVED/CGRP_DEAD/ s/cgroup_is_removed()/cgroup_is_dead() This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f4f4be2bd2889c69a8698edef8dbfd4f6759aa87 |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: use kzalloc() instead of kmalloc() There's no point in using kmalloc() instead of the clearing variant for trivial stuff. We can live dangerously elsewhere. Use kzalloc() instead and drop 0 inits. While at it, do trivial code reorganization in cgroup_file_open(). This patch doesn't introduce any functional changes. v2: I was caught in the very distant past where list_del() didn't poison and the initial version converted list_del()s to list_del_init()s too. Li and Kent took me out of the stasis chamber. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Kent Overstreet <koverstreet@google.com> Acked-by: Li Zefan <lizefan@huawei.com>
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69d0206c793a17431eacee2694ee7a4b25df76b7 |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: bring some sanity to naming around cg_cgroup_link cgroups and css_sets are mapped M:N and this M:N mapping is represented by struct cg_cgroup_link which forms linked lists on both sides. The naming around this mapping is already confusing and struct cg_cgroup_link exacerbates the situation quite a bit. >From cgroup side, it starts off ->css_sets and runs through ->cgrp_link_list. From css_set side, it starts off ->cg_links and runs through ->cg_link_list. This is rather reversed as cgrp_link_list is used to iterate css_sets and cg_link_list cgroups. Also, this is the only place which is still using the confusing "cg" for css_sets. This patch cleans it up a bit. * s/cgroup->css_sets/cgroup->cset_links/ s/css_set->cg_links/css_set->cgrp_links/ s/cgroup_iter->cg_link/cgroup_iter->cset_link/ * s/cg_cgroup_link/cgrp_cset_link/ * s/cgrp_cset_link->cg/cgrp_cset_link->cset/ s/cgrp_cset_link->cgrp_link_list/cgrp_cset_link->cset_link/ s/cgrp_cset_link->cg_link_list/cgrp_cset_link->cgrp_link/ * s/init_css_set_link/init_cgrp_cset_link/ s/free_cg_links/free_cgrp_cset_links/ s/allocate_cg_links/allocate_cgrp_cset_links/ * s/cgl[12]/link[12]/ in compare_css_sets() * s/saved_link/tmp_link/ s/tmp/tmp_links/ and a couple similar adustments. * Comment and whiteline adjustments. After the changes, we have list_for_each_entry(link, &cont->cset_links, cset_link) { struct css_set *cset = link->cset; instead of list_for_each_entry(link, &cont->css_sets, cgrp_link_list) { struct css_set *cset = link->cg; This patch is purely cosmetic. v2: Fix broken sentences in the patch description. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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5abb8855734fd7b3fa7f91c13916d0e35d99763c |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: consistently use @cset for struct css_set variables cgroup.c uses @cg for most struct css_set variables, which in itself could be a bit confusing, but made much worse by the fact that there are places which use @cg for struct cgroup variables. compare_css_sets() epitomizes this confusion - @[old_]cg are struct css_set while @cg[12] are struct cgroup. It's not like the whole deal with cgroup, css_set and cg_cgroup_link isn't already confusing enough. Let's give it some sanity by uniformly using @cset for all struct css_set variables. * s/cg/cset/ for all css_set variables. * s/oldcg/old_cset/ s/oldcgrp/old_cgrp/. The same for the ones prefixed with "new". * s/cg/cgrp/ for cgroup variables in compare_css_sets(). * s/css/cset/ for the cgroup variable in task_cgroup_from_root(). * Whiteline adjustments. This patch is purely cosmetic. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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3fc3db9a3ae0ce108badf31a4a00e41b4236f5fc |
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13-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove now unused css_depth() Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d5c56ced775f6bdc32b689b01c9c4f9b66e18610 |
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04-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: clean up the cftype array for the base cgroup files * Rename it from files[] (really?) to cgroup_base_files[]. * Drop CGROUP_FILE_GENERIC_PREFIX which was defined as "cgroup." and used inconsistently. Just use "cgroup." directly. * Collect insane files at the end. Note that only the insane ones are missing "cgroup." prefix. This patch doesn't introduce any functional changes. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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cc5943a7816ba6c00639837a62131386619548dc |
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04-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: mark "notify_on_release" and "release_agent" cgroup files insane The empty cgroup notification mechanism currently implemented in cgroup is tragically outdated. Forking and execing userland process stopped being a viable notification mechanism more than a decade ago. We're gonna have a saner mechanism. Let's make it clear that this abomination is going away. Mark "notify_on_release" and "release_agent" with CFTYPE_INSANE. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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f12dc020149fad7087e119e54cffea668272bf7d |
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04-Jun-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: mark "tasks" cgroup file as insane Some resources controlled by cgroup aren't per-task and cgroup core allowing threads of a single thread_group to be in different cgroups forced memcg do explicitly find the group leader and use it. This is gonna be nasty when transitioning to unified hierarchy and in general we don't want and won't support granularity finer than processes. Mark "tasks" with CFTYPE_INSANE. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: cgroups@vger.kernel.org Cc: Vivek Goyal <vgoyal@redhat.com>
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2a0ff3fbe39bc93f719ff857e5a359d9780579ff |
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26-May-2013 |
Jeff Liu <jeff.liu@oracle.com> |
cgroup: warn about mismatching options of a new mount of an existing hierarchy With the new __DEVEL__sane_behavior mount option was introduced, if the root cgroup is alive with no xattr function, to mount a new cgroup with xattr will be rejected in terms of design which just fine. However, if the root cgroup does not mounted with __DEVEL__sane_hehavior, to create a new cgroup with xattr option will succeed although after that the EA function does not works as expected but will get ENOTSUPP for setting up attributes under either cgroup. e.g. setfattr: /cgroup2/test: Operation not supported Instead of keeping silence in this case, it's better to drop a log entry in warning level. That would be helpful to understand the reason behind the scene from the user's perspective, and this is essentially an improvement does not break the backward compatibilities. With this fix, above mount attemption will keep up works as usual but the following line cound be found at the system log: [ ...] cgroup: new mount options do not match the existing superblock tj: minor formatting / message updates. Signed-off-by: Jie Liu <jeff.liu@oracle.com> Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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75501a6d59e989e5c286716e5b3b66ace4660e83 |
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24-May-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: update iterators to use cgroup_next_sibling() This patch converts cgroup_for_each_child(), cgroup_next_descendant_pre/post() and thus cgroup_for_each_descendant_pre/post() to use cgroup_next_sibling() instead of manually dereferencing ->sibling.next. The only reason the iterators couldn't allow dropping RCU read lock while iteration is in progress was because they couldn't determine the next sibling safely once RCU read lock is dropped. Using cgroup_next_sibling() removes that problem and enables all iterators to allow dropping RCU read lock in the middle. Comments are updated accordingly. This makes the iterators easier to use and will simplify controllers. Note that @cgroup argument is renamed to @cgrp in cgroup_for_each_child() because it conflicts with "struct cgroup" used in the new macro body. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz>
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53fa5261747a90746531e8a1c81eeb78fedc2f71 |
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24-May-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup->serial_nr and implement cgroup_next_sibling() Currently, there's no easy way to find out the next sibling cgroup unless it's known that the current cgroup is accessed from the parent's children list in a single RCU critical section. This in turn forces all iterators to require whole iteration to be enclosed in a single RCU critical section, which sometimes is too restrictive. This patch implements cgroup_next_sibling() which can reliably determine the next sibling regardless of the state of the current cgroup as long as it's accessible. It currently is impossible to determine the next sibling after dropping RCU read lock because the cgroup being iterated could be removed anytime and if RCU read lock is dropped, nothing guarantess its ->sibling.next pointer is accessible. A removed cgroup would continue to point to its next sibling for RCU accesses but stop receiving updates from the sibling. IOW, the next sibling could be removed and then complete its grace period while RCU read lock is dropped, making it unsafe to dereference ->sibling.next after dropping and re-acquiring RCU read lock. This can be solved by adding a way to traverse to the next sibling without dereferencing ->sibling.next. This patch adds a monotonically increasing cgroup serial number, cgroup->serial_nr, which guarantees that all cgroup->children lists are kept in increasing serial_nr order. A new function, cgroup_next_sibling(), is implemented, which, if CGRP_REMOVED is not set on the current cgroup, follows ->sibling.next; otherwise, traverses the parent's ->children list until it sees a sibling with higher ->serial_nr. This allows the function to always return the next sibling regardless of the state of the current cgroup without adding overhead in the fast path. Further patches will update the iterators to use cgroup_next_sibling() so that they allow dropping RCU read lock and blocking while iteration is in progress which in turn will be used to simplify controllers. v2: Typo fix as per Serge. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
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bdc7119f1bdd0632d42f435941dc290216a436e7 |
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24-May-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_is_removed() static cgroup_is_removed() no longer has external users and it shouldn't grow any - controllers should deal with cgroup_subsys_state on/offline state instead of cgroup removal state. Make it static. While at it, make it return bool. Signed-off-by: Tejun Heo <tj@kernel.org>
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7805d000db30a3787a4c969bab6ae4d8a5fd8ce6 |
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24-May-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: fix a subtle bug in descendant pre-order walk When cgroup_next_descendant_pre() initiates a walk, it checks whether the subtree root doesn't have any children and if not returns NULL. Later code assumes that the subtree isn't empty. This is broken because the subtree may become empty inbetween, which can lead to the traversal escaping the subtree by walking to the sibling of the subtree root. There's no reason to have the early exit path. Remove it along with the later assumption that the subtree isn't empty. This simplifies the code a bit and fixes the subtle bug. While at it, fix the comment of cgroup_for_each_descendant_pre() which was incorrectly referring to ->css_offline() instead of ->css_online(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: stable@vger.kernel.org
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857a2beb09ab83e9a8185821ae16db7dfbe8b837 |
|
15-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement task_cgroup_path_from_hierarchy() kdbus folks want a sane way to determine the cgroup path that a given task belongs to on a given hierarchy, which is a reasonble thing to expect from cgroup core. Implement task_cgroup_path_from_hierarchy(). v2: Dropped unnecessary NULL check on the return value of task_cgroup_from_root() as suggested by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Greg Kroah-Hartman <greg@kroah.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Lennart Poettering <lennart@poettering.net> Cc: Daniel Mack <daniel@zonque.org>
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1a574231669f8c3065c83974e9557fcbbd94b8a6 |
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14-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make hierarchy_id use cyclic idr We want to be able to lookup a hierarchy from its id and cyclic allocation is a whole lot simpler with idr. Convert to idr and use idr_alloc_cyclc(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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54e7b4eb15fc4354d5ada5469e3db4a220ddb3ed |
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14-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: drop hierarchy_id_lock Now that hierarchy_id alloc / free are protected by the cgroup mutexes, there's no need for this separate lock. Drop it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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fa3ca07e96185aa1496b405472399a2a2a336a17 |
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14-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: refactor hierarchy_id handling We're planning to converting hierarchy_ida to an idr and use it to look up hierarchy from its id. As we want the mapping to happen atomically with cgroupfs_root registration, this patch refactors hierarchy_id init / exit so that ida operations happen inside cgroup_[root_]mutex. * s/init_root_id()/cgroup_init_root_id()/ and make it return 0 or -errno like a normal function. * Move hierarchy_id initialization from cgroup_root_from_opts() into cgroup_mount() block where the root is confirmed to be used and being registered while holding both mutexes. * Split cgroup_drop_id() into cgroup_exit_root_id() and cgroup_free_root(), so that ID release can happen before dropping the mutexes in cgroup_kill_sb(). The latter expects hierarchy_id to be exited before being invoked. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d6cbf35dac8a3dadb9103379820c96d7c85df3d9 |
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14-May-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: initialize xattr before calling d_instantiate() cgroup_create_file() calls d_instantiate(), which may decide to look at the xattrs on the file. Smack always does this and SELinux can be configured to do so. But cgroup_add_file() didn't initialize xattrs before calling cgroup_create_file(), which finally leads to dereferencing NULL dentry->d_fsdata. This bug has been there since cgroup xattr was introduced. Cc: <stable@vger.kernel.org> # 3.8.x Reported-by: Ivan Bulatovic <combuster@archlinux.us> Reported-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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8d8b97ba499cb69fccb5fd9f2b439e3265fc3f27 |
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20-Apr-2013 |
Al Viro <viro@zeniv.linux.org.uk> |
take cgroup_open() and cpuset_open() to fs/proc/base.c Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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6d2488f64a240191f0733c1f32d73607916b01b7 |
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30-Apr-2013 |
Michal Hocko <mhocko@suse.cz> |
cgroup: remove css_get_next Now that we have generic and well ordered cgroup tree walkers there is no need to keep css_get_next in the place. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Ying Han <yinghan@google.com> Cc: Tejun Heo <htejun@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7ef70e48735e17d2be5c8e8f85052842b16b923a |
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26-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: restore the call to eventfd->poll() I mistakenly removed the call to eventfd->poll() while I was actually intending to remove the return value... Calling evenfd->poll() will hook cgroup_event_wake() to the poll waitqueue, which will be called to unregister eventfd when rmdir a cgroup or close eventfd. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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cc20e01cd607282d48f8ea538aba10fa850a4312 |
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26-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix use-after-free when umounting cgroupfs Try: # mount -t cgroup xxx /cgroup # mkdir /cgroup/sub && rmdir /cgroup/sub && umount /cgroup And you might see this: ida_remove called for id=1 which is not allocated. It's because cgroup_kill_sb() is called to destroy root->cgroup_ida and free cgrp->root before ida_simple_removed() is called. What's worse is we're accessing cgrp->root while it has been freed. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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712317ad97f41e738e1a19aa0a6392a78a84094e |
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19-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix broken file xattrs We should store file xattrs in struct cfent instead of struct cftype, because cftype is a type while cfent is object instance of cftype. For example each cgroup has a tasks file, and each tasks file is associated with a uniq cfent, but all those files share the same struct cftype. Alexey Kodanev reported a crash, which can be reproduced: # mount -t cgroup -o xattr /sys/fs/cgroup # mkdir /sys/fs/cgroup/test # setfattr -n trusted.value -v test_value /sys/fs/cgroup/tasks # rmdir /sys/fs/cgroup/test # umount /sys/fs/cgroup oops! In this case, simple_xattrs_free() will free the same struct simple_xattrs twice. tj: Dropped unused local variable @cft from cgroup_diput(). Cc: <stable@vger.kernel.org> # 3.8.x Reported-by: Alexey Kodanev <alexey.kodanev@oracle.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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05fb22ec5456a472a5eadcaacb3e51eca1f8c79c |
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15-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove cgrp->top_cgroup It's not used, and it can be retrieved via cgrp->root->top_cgroup. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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873fe09ea5df6ccf6bb34811d8c9992aacb67598 |
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15-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce sane_behavior mount option It's a sad fact that at this point various cgroup controllers are carrying so many idiosyncrasies and pure insanities that it simply isn't possible to reach any sort of sane consistent behavior while maintaining staying fully compatible with what already has been exposed to userland. As we can't break exposed userland interface, transitioning to sane behaviors can only be done in steps while maintaining backwards compatibility. This patch introduces a new mount option - __DEVEL__sane_behavior - which disables crazy features and enforces consistent behaviors in cgroup core proper and various controllers. As exactly which behaviors it changes are still being determined, the mount option, at this point, is useful only for development of the new behaviors. As such, the mount option is prefixed with __DEVEL__ and generates a warning message when used. Eventually, once we get to the point where all controller's behaviors are consistent enough to implement unified hierarchy, the __DEVEL__ prefix will be dropped, and more importantly, unified-hierarchy will enforce sane_behavior by default. Maybe we'll able to completely drop the crazy stuff after a while, maybe not, but we at least have a strategy to move on to saner behaviors. This patch introduces the mount option and changes the following behaviors in cgroup core. * Mount options "noprefix" and "clone_children" are disallowed. Also, cgroupfs file cgroup.clone_children is not created. * When mounting an existing superblock, mount options should match. This is currently pretty crazy. If one mounts a cgroup, creates a subdirectory, unmounts it and then mount it again with different option, it looks like the new options are applied but they aren't. * Remount is disallowed. The behaviors changes are documented in the comment above CGRP_ROOT_SANE_BEHAVIOR enum and will be expanded as different controllers are converted and planned improvements progress. v2: Dropped unnecessary explicit file permission setting sane_behavior cftype entry as suggested by Li Zefan. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vivek Goyal <vgoyal@redhat.com>
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25a7e6848db76e22677aff202d9c4ef3503be15b |
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15-Apr-2013 |
Tejun Heo <tj@kernel.org> |
move cgroupfs_root to include/linux/cgroup.h While controllers shouldn't be accessing cgroupfs_root directly, it being hidden inside kern/cgroup.c makes somethings pretty silly. This makes routing hierarchy-wide settings which need to be visible to controllers cumbersome. We're gonna add another hierarchy-wide setting which needs to be accessed from controllers. Move cgroupfs_root and its flags to the header file so that we can access root settings with inline helpers. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com>
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9343862945fdd3dd5cb7648bb24cabe40faa9ad9 |
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15-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: convert cgroupfs_root flag bits to masks and add CGRP_ prefix There's no reason to be using bitops, which tends to be more cumbersome, to handle root flags. Convert them to masks. Also, as they'll be moved to include/linux/cgroup.h and it's generally a good idea, add CGRP_ prefix. Note that flags are assigned from (1 << 1). The first bit will be used by a flag which will be added soon. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com>
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da1f296fd2bfd5ad3c53d72a1ece593e821cf374 |
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14-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: make cgroup_path() not print double slashes While reimplementing cgroup_path(), 65dff759d2 ("cgroup: fix cgroup_path() vs rename() race") introduced a bug where the path of a non-root cgroup would have two slahses at the beginning, which is caused by treating the root cgroup which has the name '/' like non-root cgroups. $ grep systemd /proc/self/cgroup 1:name=systemd://user/root/1 Fix it by special casing root cgroup case and not looping over it in the normal path. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com>
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26d5bbe5ba2073fc7ef9e69a55543b2376f5bad0 |
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12-Apr-2013 |
Tejun Heo <tj@kernel.org> |
Revert "cgroup: remove bind() method from cgroup_subsys." This reverts commit 84cfb6ab484b442d5115eb3baf9db7d74a3ea626. There are scheduled changes which make use of the removed callback. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rami Rosen <ramirose@gmail.com> Cc: Li Zefan <lizefan@huawei.com>
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78574cf981cd3d9ae9f6adbd466a772310ec24ff |
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09-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: implement cgroup_is_descendant() A couple controllers want to determine whether two cgroups are in ancestor/descendant relationship. As it's more likely that the descendant is the primary subject of interest and there are other operations focusing on the descendants, let's ask is_descendent rather than is_ancestor. Implementation is trivial as the previous patch guarantees that all ancestors of a cgroup stay accessible as long as the cgroup is accessible. tj: Removed depth optimization, renamed from cgroup_is_ancestor(), rewrote descriptions. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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415cf07a1c1c65249773330434878ae7bcd92d0f |
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08-Apr-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: make sure parent won't be destroyed before its children Suppose we rmdir a cgroup and there're still css refs, this cgroup won't be freed. Then we rmdir the parent cgroup, and the parent is freed immediately due to css ref draining to 0. Now it would be a disaster if the still-alive child cgroup tries to access its parent. Make sure this won't happen. Signed-off-by: Li Zefan <lizefan@huawei.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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84cfb6ab484b442d5115eb3baf9db7d74a3ea626 |
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10-Apr-2013 |
Rami Rosen <ramirose@gmail.com> |
cgroup: remove bind() method from cgroup_subsys. The bind() method of cgroup_subsys is not used in any of the controllers (cpuset, freezer, blkio, net_cls, memcg, net_prio, devices, perf, hugetlb, cpu and cpuacct) tj: Removed the entry on ->bind() from Documentation/cgroups/cgroups.txt. Also updated a couple paragraphs which were suggesting that dynamic re-binding may be implemented. It's not gonna. Signed-off-by: Rami Rosen <ramirose@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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479f614110b889d5783acdaec865ede3cdb96b97 |
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29-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: Kill subsys.active flag The only user was cpuacct. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5155385A.4040207@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2219449a65ace0290cd9c2260ff337e326b8be8a |
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07-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_lock_is_held() We don't want controllers to assume that the information is officially available and do funky things with it. The only user is task_subsys_state_check() which uses it to verify RCU access context. We can move cgroup_lock_is_held() inside CONFIG_PROVE_RCU but that doesn't add meaningful protection compared to conditionally exposing cgroup_mutex. Remove cgroup_lock_is_held(), export cgroup_mutex iff CONFIG_PROVE_RCU and use lockdep_is_held() directly on the mutex in task_subsys_state_check(). While at it, add parentheses around macro arguments in task_subsys_state_check(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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47cfcd0922454e49f4923b1e2d31a5bf199237c3 |
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07-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: kill cgroup_[un]lock() Now that locking interface is unexported, there's no reason to keep around these thin wrappers. Kill them and use mutex operations directly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b9777cf8d7c7854c3c38bd6621d993b85c2afcdf |
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07-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: unexport locking interface and cgroup_attach_task() Now that all external cgroup_lock() users are gone, we can finally unexport the locking interface and prevent future abuse of cgroup_mutex. Make cgroup_[un]lock() and cgroup_lock_live_group() static. Also, cgroup_attach_task() doesn't have any user left and can't be used without locking interface anyway. Make it static too. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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7ae1bad99e27b8838d480a24edf4646a2fc547df |
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07-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate cgroup_lock_live_group() and cgroup_attach_task_all() cgroup_lock_live_group() and cgroup_attach_task() are scheduled to be made static. Relocate the former and cgroup_attach_task_all() so that we don't need forward declarations. This patch is pure relocation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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8cc9934520e7f752fe45d5199664d741ba24a932 |
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07-Apr-2013 |
Tejun Heo <tj@kernel.org> |
cgroup, cpuset: replace move_member_tasks_to_cpuset() with cgroup_transfer_tasks() When a cpuset becomes empty (no CPU or memory), its tasks are transferred with the nearest ancestor with execution resources. This is implemented using cgroup_scan_tasks() with a callback which grabs cgroup_mutex and invokes cgroup_attach_task() on each task. Both cgroup_mutex and cgroup_attach_task() are scheduled to be unexported. Implement cgroup_transfer_tasks() in cgroup proper which is essentially the same as move_member_tasks_to_cpuset() except that it takes cgroups instead of cpusets and @to comes before @from like normal functions with those arguments, and replace move_member_tasks_to_cpuset() with it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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1e2ccd1c0f67c3f958d6139de2496787b9a57182 |
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01-Apr-2013 |
Kevin Wilson <wkevils@gmail.com> |
cgroup: remove unused parameter in cgroup_task_migrate(). This patch removes unused parameter from cgroup_task_migrate(). Signed-off-by: Kevin Wilson <wkevils@gmail.com> Acked-by: Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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081aa458c38ba576bdd4265fc807fa95b48b9e79 |
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13-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: consolidate cgroup_attach_task() and cgroup_attach_proc() These two functions share most of the code. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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3ac1707a13a3da9cfc8f242a15b2fae6df2c5f88 |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix an off-by-one bug which may trigger BUG_ON() The 3rd parameter of flex_array_prealloc() is the number of elements, not the index of the last element. The effect of the bug is, when opening cgroup.procs, a flex array will be allocated and all elements of the array is allocated with GFP_KERNEL flag, but the last one is GFP_ATOMIC, and if we fail to allocate memory for it, it'll trigger a BUG_ON(). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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14a40ffccd6163bbcd1d6f32b28a88ffe6149fc6 |
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19-Mar-2013 |
Tejun Heo <tj@kernel.org> |
sched: replace PF_THREAD_BOUND with PF_NO_SETAFFINITY PF_THREAD_BOUND was originally used to mark kernel threads which were bound to a specific CPU using kthread_bind() and a task with the flag set allows cpus_allowed modifications only to itself. Workqueue is currently abusing it to prevent userland from meddling with cpus_allowed of workqueue workers. What we need is a flag to prevent userland from messing with cpus_allowed of certain kernel tasks. In kernel, anyone can (incorrectly) squash the flag, and, for worker-type usages, restricting cpus_allowed modification to the task itself doesn't provide meaningful extra proection as other tasks can inject work items to the task anyway. This patch replaces PF_THREAD_BOUND with PF_NO_SETAFFINITY. sched_setaffinity() checks the flag and return -EINVAL if set. set_cpus_allowed_ptr() is no longer affected by the flag. This will allow simplifying workqueue worker CPU affinity management. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Ingo Molnar <mingo@kernel.org> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de>
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80f36c2a1a612ca419e5b864a7e4808e797d9feb |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove useless code in cgroup_write_event_control() eventfd_poll() never returns POLLHUP. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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6ee211ad0a22869af81eef10845922ac4dcb2d38 |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: don't bother to resize pid array When we open cgroup.procs, we'll allocate an buffer and store all tasks' tgid in it, and then duplicate entries will be stripped. If that results in a much smaller pid list, we'll re-allocate a smaller buffer. But we've already sucessfully allocated memory and reading the procs file is a short period and the memory will be freed very soon, so why bother to re-allocate memory. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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d7eeac1913ff86a17f891cb4b73f03d4b94907d0 |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: hold cgroup_mutex before calling css_offline() cpuset no longer nests cgroup_mutex inside cpu_hotplug lock, so we don't have to release cgroup_mutex before calling css_offline(). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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6dc01181eac16192dc4a5d1b310b78e2e97c003c |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove unused variables in cgroup_destroy_locked() Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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e7b2dcc52b0e2d598a469f01cc460ccdde6869f2 |
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12-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove cgroup_is_descendant() It was used by ns cgroup, and ns cgroup was removed long ago. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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7d8e0bf56a66bab08d2f316dd87e56c08cecb899 |
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05-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: avoid accessing modular cgroup subsys structure without locking subsys[i] is set to NULL in cgroup_unload_subsys() at modular unload, and that's protected by cgroup_mutex, and then the memory *subsys[i] resides will be freed. So this is unsafe without any locking: if (!ss || ss->module) ... v2: - add a comment for enum cgroup_subsys_id - simplify the comment in cgroup_exit() Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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f50daa704f36a6544a902c52b6cf37b0493dfc5d |
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01-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: no need to check css refs for release notification We no longer fail rmdir() when there're still css refs, so we don't need to check css refs in check_for_release(). This also voids a bug. cgroup_has_css_refs() accesses subsys[i] without cgroup_mutex, so it can race with cgroup_unload_subsys(). cgroup_has_css_refs() ... if (ss == NULL || ss->root != cgrp->root) if ss pointers to net_cls_subsys, and cls_cgroup module is unloaded right after the former check but before the latter, the memory that net_cls_subsys resides has become invalid. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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65dff759d2948cf18e2029fc5c0c595b8b7da3a5 |
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01-Mar-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix cgroup_path() vs rename() race rename() will change dentry->d_name. The result of this race can be worse than seeing partially rewritten name, but we might access a stale pointer because rename() will re-allocate memory to hold a longer name. As accessing dentry->name must be protected by dentry->d_lock or parent inode's i_mutex, while on the other hand cgroup-path() can be called with some irq-safe spinlocks held, we can't generate cgroup path using dentry->d_name. Alternatively we make a copy of dentry->d_name and save it in cgrp->name when a cgroup is created, and update cgrp->name at rename(). v5: use flexible array instead of zero-size array. v4: - allocate root_cgroup_name and all root_cgroup->name points to it. - add cgroup_name() wrapper. v3: use kfree_rcu() instead of synchronize_rcu() in user-visible path. v2: make cgrp->name RCU safe. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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b67bfe0d42cac56c512dd5da4b1b347a23f4b70a |
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28-Feb-2013 |
Sasha Levin <sasha.levin@oracle.com> |
hlist: drop the node parameter from iterators I'm not sure why, but the hlist for each entry iterators were conceived list_for_each_entry(pos, head, member) The hlist ones were greedy and wanted an extra parameter: hlist_for_each_entry(tpos, pos, head, member) Why did they need an extra pos parameter? I'm not quite sure. Not only they don't really need it, it also prevents the iterator from looking exactly like the list iterator, which is unfortunate. Besides the semantic patch, there was some manual work required: - Fix up the actual hlist iterators in linux/list.h - Fix up the declaration of other iterators based on the hlist ones. - A very small amount of places were using the 'node' parameter, this was modified to use 'obj->member' instead. - Coccinelle didn't handle the hlist_for_each_entry_safe iterator properly, so those had to be fixed up manually. The semantic patch which is mostly the work of Peter Senna Tschudin is here: @@ iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host; type T; expression a,c,d,e; identifier b; statement S; @@ -T b; <+... when != b ( hlist_for_each_entry(a, - b, c, d) S | hlist_for_each_entry_continue(a, - b, c) S | hlist_for_each_entry_from(a, - b, c) S | hlist_for_each_entry_rcu(a, - b, c, d) S | hlist_for_each_entry_rcu_bh(a, - b, c, d) S | hlist_for_each_entry_continue_rcu_bh(a, - b, c) S | for_each_busy_worker(a, c, - b, d) S | ax25_uid_for_each(a, - b, c) S | ax25_for_each(a, - b, c) S | inet_bind_bucket_for_each(a, - b, c) S | sctp_for_each_hentry(a, - b, c) S | sk_for_each(a, - b, c) S | sk_for_each_rcu(a, - b, c) S | sk_for_each_from -(a, b) +(a) S + sk_for_each_from(a) S | sk_for_each_safe(a, - b, c, d) S | sk_for_each_bound(a, - b, c) S | hlist_for_each_entry_safe(a, - b, c, d, e) S | hlist_for_each_entry_continue_rcu(a, - b, c) S | nr_neigh_for_each(a, - b, c) S | nr_neigh_for_each_safe(a, - b, c, d) S | nr_node_for_each(a, - b, c) S | nr_node_for_each_safe(a, - b, c, d) S | - for_each_gfn_sp(a, c, d, b) S + for_each_gfn_sp(a, c, d) S | - for_each_gfn_indirect_valid_sp(a, c, d, b) S + for_each_gfn_indirect_valid_sp(a, c, d) S | for_each_host(a, - b, c) S | for_each_host_safe(a, - b, c, d) S | for_each_mesh_entry(a, - b, c, d) S ) ...+> [akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c] [akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c] [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: fix warnings] [akpm@linux-foudnation.org: redo intrusive kvm changes] Tested-by: Peter Senna Tschudin <peter.senna@gmail.com> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d228d9ec2c9a119ce15c6446ebeec05786ab3287 |
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28-Feb-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: convert to idr_alloc() Convert to the much saner new idr interface. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c897ff68beec97768c31f9de97de93f77ff2d87e |
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28-Feb-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: don't use idr_remove_all() idr_destroy() can destroy idr by itself and idr_remove_all() is being deprecated. Drop its usage. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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496ad9aa8ef448058e36ca7a787c61f2e63f0f54 |
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23-Jan-2013 |
Al Viro <viro@zeniv.linux.org.uk> |
new helper: file_inode(file) Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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f169007b2773f285e098cb84c74aac0154d65ff7 |
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18-Feb-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fail if monitored file and event_control are in different cgroup If we pass fd of memory.usage_in_bytes of cgroup A to cgroup.event_control of cgroup B, then we won't get memory usage notification from A but B! What's worse, if A and B are in different mount hierarchy, we'll end up accessing NULL pointer! Disallow this kind of invalid usage. Signed-off-by: Li Zefan <lizefan@huawei.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Tejun Heo <tj@kernel.org>
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810cbee4fad570ff167132d4ecf247d99c48f71d |
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18-Feb-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix cgroup_rmdir() vs close(eventfd) race commit 205a872bd6f9a9a09ef035ef1e90185a8245cc58 ("cgroup: fix lockdep warning for event_control") solved a deadlock by introducing a new bug. Move cgrp->event_list to a temporary list doesn't mean you can traverse this list locklessly, because at the same time cgroup_event_wake() can be called and remove the event from the list. The result of this race is disastrous. We adopt the way how kvm irqfd code implements race-free event removal, which is now described in the comments in cgroup_event_wake(). v3: - call eventfd_signal() no matter it's eventfd close or cgroup removal that removes the cgroup event. Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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71b5707e119653039e6e95213f00479668c79b75 |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix exit() vs rmdir() race In cgroup_exit() put_css_set_taskexit() is called without any lock, which might lead to accessing a freed cgroup: thread1 thread2 --------------------------------------------- exit() cgroup_exit() put_css_set_taskexit() atomic_dec(cgrp->count); rmdir(); /* not safe !! */ check_for_release(cgrp); rcu_read_lock() can be used to make sure the cgroup is alive. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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9ed8a659703876a9fe96ab86d1b296c2f0084242 |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove bogus comments in cgroup_diput() Since commit 48ddbe194623ae089cc0576e60363f2d2e85662a ("cgroup: make css->refcnt clearing on cgroup removal optional"), each css holds a ref on cgroup's dentry, so cgroup_diput() won't be called until all css' refs go down to 0, which invalids the comments. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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be44562613851235d801d41d5b3976dc4333f622 |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove synchronize_rcu() from cgroup_diput() Free cgroup via call_rcu(). The actual work is done through workqueue. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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86a3db5643c7d29bb36ca85c7a4bb67ad4d88d77 |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove duplicate RCU free on struct cgroup When destroying a cgroup, though in cgroup_diput() we've called synchronize_rcu(), we then still have to free it via call_rcu(). The story is, long ago to fix a race between reading /proc/sched_debug and freeing cgroup, the code was changed to utilize call_rcu(). See commit a47295e6bc42ad35f9c15ac66f598aa24debd4e2 ("cgroups: make cgroup_path() RCU-safe") As we've fixed cpu cgroup that cpu_cgroup_offline_css() is used to unregister a task_group so there won't be concurrent access to this task_group after synchronize_rcu() in diput(). Now we can just kfree(cgrp). Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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fe1c06ca7523baa668c1eaf1e1016fa64753c32e |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: initialize cgrp->dentry before css_alloc() With this change, we're guaranteed that cgroup_path() won't see NULL cgrp->dentry, and thus we can remove the NULL check in it. (Well, it's not strictly true, because dummptop.dentry is always NULL but we already handle that separately.) Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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b5d646f5d5a135064232ff3a140a47a5b84bc911 |
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24-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove a NULL check in cgroup_exit() init_task.cgroups is initialized at boot phase, and whenver a ask is forked, it's cgroups pointer is inherited from its parent, and it's never set to NULL afterwards. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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2739d3cce9816805fe26774fea2527d5b16e924d |
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21-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: fix bogus kernel warnings when cgroup_create() failed If cgroup_create() failed and cgroup_destroy_locked() is called to do cleanup, we'll see a bunch of warnings: cgroup_addrm_files: failed to remove 2MB.limit_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.usage_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.max_usage_in_bytes, err=-2 cgroup_addrm_files: failed to remove 2MB.failcnt, err=-2 cgroup_addrm_files: failed to remove prioidx, err=-2 cgroup_addrm_files: failed to remove ifpriomap, err=-2 ... We failed to remove those files, because cgroup_create() has failed before creating those cgroup files. To fix this, we simply don't warn if cgroup_rm_file() can't find the cft entry. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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130e3695a3edf6bf21464f2826720a79a6afdee0 |
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14-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove synchronize_rcu() from rebind_subsystems() Nothing's protected by RCU in rebind_subsystems(), and I can't think of a reason why it is needed. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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5d65bc0ca1bceb73204dab943922ba3c83276a8c |
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14-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove synchronize_rcu() from cgroup_attach_{task|proc}() These 2 syncronize_rcu()s make attaching a task to a cgroup quite slow, and it can't be ignored in some situations. A real case from Colin Cross: Android uses cgroups heavily to manage thread priorities, putting threads in a background group with reduced cpu.shares when they are not visible to the user, and in a foreground group when they are. Some RPCs from foreground threads to background threads will temporarily move the background thread into the foreground group for the duration of the RPC. This results in many calls to cgroup_attach_task. In cgroup_attach_task() it's task->cgroups that is protected by RCU, and put_css_set() calls kfree_rcu() to free it. If we remove this synchronize_rcu(), there can be threads in RCU-read sections accessing their old cgroup via current->cgroups with concurrent rmdir operation, but this is safe. # time for ((i=0; i<50; i++)) { echo $$ > /mnt/sub/tasks; echo $$ > /mnt/tasks; } real 0m2.524s user 0m0.008s sys 0m0.004s With this patch: real 0m0.004s user 0m0.004s sys 0m0.000s tj: These synchronize_rcu()s are utterly confused. synchornize_rcu() necessarily has to come between two operations to guarantee that the changes made by the former operation are visible to all rcu readers before proceeding to the latter operation. Here, synchornize_rcu() are at the end of attach operations with nothing beyond it. Its only effect would be delaying completion of write(2) to sysfs tasks/procs files until all rcu readers see the change, which doesn't mean anything. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Colin Cross <ccross@google.com>
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0ac801fe07374148714b5ef53df90ac5b1673c0c |
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10-Jan-2013 |
Li Zefan <lizefan@huawei.com> |
cgroup: use new hashtable implementation Switch cgroup to use the new hashtable implementation. No functional changes. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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12a9d2fef1d35770d3cdc2cd1faabb83c45bc0fa |
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07-Jan-2013 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_rightmost_descendant() Implement cgroup_rightmost_descendant() which returns the right most descendant of the specified cgroup. This can be used to skip the cgroup's subtree while iterating with cgroup_for_each_descendant_pre(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com>
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8ec7d50f1ed2b072d23ce810f86df09ee0568d4b |
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18-Dec-2012 |
Tao Ma <boyu.mt@taobao.com> |
kernel: remove reference to feature-removal-schedule.txt In commit 9c0ece069b32 ("Get rid of Documentation/feature-removal.txt"), Linus removed feature-removal-schedule.txt from Documentation, but there is still some reference to this file. So remove them. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f33fddc2b9573d8359f1007d4bbe5cd587a0c093 |
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06-Dec-2012 |
Gao feng <gaofeng@cn.fujitsu.com> |
cgroup_rm_file: don't delete the uncreated files in cgroup_add_file,when creating files for cgroup, some of creation may be skipped. So we need to avoid deleting these uncreated files in cgroup_rm_file, otherwise the warning msg will be triggered. "cgroup_addrm_files: failed to remove memory_pressure_enabled, err=-2" Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@redhat.com> Cc: stable@vger.kernel.org
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7083d0378a1746f2b45729cae494c6b92e75d73f |
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03-Dec-2012 |
Gao feng <gaofeng@cn.fujitsu.com> |
cgroup: remove subsystem files when remounting cgroup cgroup_clear_directroy is called by cgroup_d_remove_dir and cgroup_remount. when we call cgroup_remount to remount the cgroup,the subsystem may be unlinked from cgroupfs_root->subsys_list in rebind_subsystem,this subsystem's files will not be removed in cgroup_clear_directroy. And the system will panic when we try to access these files. this patch removes subsystems's files before rebind_subsystems, if rebind_subsystems failed, repopulate these removed files. With help from Tejun. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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879a3d9dbbde823ac77d39131e7a287f31b8296f |
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30-Nov-2012 |
Gao feng <gaofeng@cn.fujitsu.com> |
cgroup: use cgroup_addrm_files() in cgroup_clear_directory() cgroup_clear_directory() incorrectly invokes cgroup_rm_file() on each cftset of the target subsystems, which only removes the first file of each set. This leaves dangling files after subsystems are removed from a cgroup root via remount. Use cgroup_addrm_files() to remove all files of target subsystems. tj: Move cgroup_addrm_files() prototype decl upwards next to other global declarations. Commit message updated. Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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1f869e8711d18aaf6e2979922bc9377ad394b82f |
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30-Nov-2012 |
Glauber Costa <glommer@parallels.com> |
cgroup: warn about broken hierarchies only after css_online If everything goes right, it shouldn't really matter if we are spitting this warning after css_alloc or css_online. If we fail between then, there are some ill cases where we would previously see the message and now we won't (like if the files fail to be created). I believe it really shouldn't matter: this message is intended in spirit to be shown when creation succeeds, but with insane settings. Signed-off-by: Glauber Costa <glommer@parallels.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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9718ceb3431acdeee9bdec5c18e18266333970aa |
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28-Nov-2012 |
Greg Thelen <gthelen@google.com> |
cgroup: list_del_init() on removed events Use list_del_init() rather than list_del() to remove events from cgrp->event_list. No functional change. This is just defensive coding. Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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205a872bd6f9a9a09ef035ef1e90185a8245cc58 |
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28-Nov-2012 |
Greg Thelen <gthelen@google.com> |
cgroup: fix lockdep warning for event_control The cgroup_event_wake() function is called with the wait queue head locked and it takes cgrp->event_list_lock. However, in cgroup_rmdir() remove_wait_queue() was being called after taking cgrp->event_list_lock. Correct the lock ordering by using a temporary list to obtain the event list to remove from the wait queue. Signed-off-by: Greg Thelen <gthelen@google.com> Signed-off-by: Aaron Durbin <adurbin@google.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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fddfb02ad0d0d3b479c2a26a8ae7e6411b34706b |
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28-Nov-2012 |
Li Zhong <zhong@linux.vnet.ibm.com> |
cgroup: move list add after list head initilization 2243076ad1 ("cgroup: initialize cgrp->allcg_node in init_cgroup_housekeeping()") initializes cgrp->allcg_node in init_cgroup_housekeeping(). Then in init_cgroup_root(), we should call init_cgroup_housekeeping() before adding it to &root->allcg_list; otherwise, we are initializing an entry already in a list. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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d0b2fdd2a51203f04ea0a5d716e033c15e0231af |
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20-Nov-2012 |
Tao Ma <boyu.mt@taobao.com> |
cgroup: remove obsolete guarantee from cgroup_task_migrate. 'guarantee' is already removed from cgroup_task_migrate, so remove the corresponding comments. Some other typos in cgroup are also changed. Cc: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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0a950f65e1e64f4e82b4b5507773848ea88bcb8e |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup->id With the introduction of generic cgroup hierarchy iterators, css_id is being phased out. It was unnecessarily complex, id'ing the wrong thing (cgroups need IDs, not CSSes) and has other oddities like not being available at ->css_alloc(). This patch adds cgroup->id, which is a simple per-hierarchy ida-allocated ID which is assigned before ->css_alloc() and released after ->css_free(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com>
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033fa1c5f5f73833598a0beb022c0048fb769dad |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup, cpuset: remove cgroup_subsys->post_clone() Currently CGRP_CPUSET_CLONE_CHILDREN triggers ->post_clone(). Now that clone_children is cpuset specific, there's no reason to have this rather odd option activation mechanism in cgroup core. cpuset can check the flag from its ->css_allocate() and take the necessary action. Move cpuset_post_clone() logic to the end of cpuset_css_alloc() and remove cgroup_subsys->post_clone(). Loosely based on Glauber's "generalize post_clone into post_create" patch. Signed-off-by: Tejun Heo <tj@kernel.org> Original-patch-by: Glauber Costa <glommer@parallels.com> Original-patch: <1351686554-22592-2-git-send-email-glommer@parallels.com> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
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2260e7fc1f18ad815324605c1ce7d5c6fd9b19a2 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: s/CGRP_CLONE_CHILDREN/CGRP_CPUSET_CLONE_CHILDREN/ clone_children is only meaningful for cpuset and will stay that way. Rename the flag to reflect that and update documentation. Also, drop clone_children() wrapper in cgroup.c. The thin wrapper is used only a few times and one of them will go away soon. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
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92fb97487a7e41b222c1417cabd1d1ab7cc3a48c |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: rename ->create/post_create/pre_destroy/destroy() to ->css_alloc/online/offline/free() Rename cgroup_subsys css lifetime related callbacks to better describe what their roles are. Also, update documentation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b1929db42f8a649d9a9e397119f628c27fd4021f |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: allow ->post_create() to fail There could be cases where controllers want to do initialization operations which may fail from ->post_create(). This patch makes ->post_create() return -errno to indicate failure and online_css() relay such failures. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
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4b8b47eb0001a89f271d671d959b235faa8f03e2 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: update cgroup_create() failure path cgroup_create() was ignoring failure of cgroupfs files. Update it such that, if file creation fails, it rolls back by calling cgroup_destroy_locked() and returns failure. Note that error out goto labels are renamed. The labels are a bit confusing but will become better w/ later cgroup operation renames. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b8a2df6a5b576d04f78f54abf254c283527d8bbc |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: use mutex_trylock() when grabbing i_mutex of a new cgroup directory All cgroup directory i_mutexes nest outside cgroup_mutex; however, new directory creation is a special case. A new cgroup directory is created while holding cgroup_mutex. Populating the new directory requires both the new directory's i_mutex and cgroup_mutex. Because all directory i_mutexes nest outside cgroup_mutex, grabbing both requires releasing cgroup_mutex first, which isn't a good idea as the new cgroup isn't yet ready to be manipulated by other cgroup opreations. This is worked around by grabbing the new directory's i_mutex while holding cgroup_mutex before making it visible. As there's no other user at that point, grabbing the i_mutex under cgroup_mutex can't lead to deadlock. cgroup_create_file() was using I_MUTEX_CHILD to tell lockdep not to worry about the reverse locking order; however, this creates pseudo locking dependency cgroup_mutex -> I_MUTEX_CHILD, which isn't true - all directory i_mutexes are still nested outside cgroup_mutex. This pseudo locking dependency can lead to spurious lockdep warnings. Use mutex_trylock() instead. This will always succeed and lockdep doesn't create any locking dependency for it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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d19e19de48aa0b90c56cd93c8a46ebac46273429 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: simplify cgroup_load_subsys() failure path Now that cgroup_unload_subsys() can tell whether the root css is online or not, we can safely call cgroup_unload_subsys() after idr init failure in cgroup_load_subsys(). Replace the manual unrolling and invoke cgroup_unload_subsys() on failure. This drops cgroup_mutex inbetween but should be safe as the subsystem will fail try_module_get() and thus can't be mounted inbetween. As this means that cgroup_unload_subsys() can be called before css_sets are rehashed, remove BUG_ON() on %NULL css_set->subsys[] from cgroup_unload_subsys(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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a31f2d3ff7fe20cbe2a143515a7d7c408b29dd0d |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce CSS_ONLINE flag and on/offline_css() helpers New helpers on/offline_css() respectively wrap ->post_create() and ->pre_destroy() invocations. online_css() sets CSS_ONLINE after ->post_create() is complete and offline_css() invokes ->pre_destroy() iff CSS_ONLINE is set and clears it while also handling the temporary dropping of cgroup_mutex. This patch doesn't introduce any behavior change at the moment but will be used to improve cgroup_create() failure path and allow ->post_create() to fail. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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42809dd4225b2f3127a4804314a1b33608620d96 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: separate out cgroup_destroy_locked() Separate out cgroup_destroy_locked() from cgroup_destroy(). This will be later used in cgroup_create() failure path. While at it, add lockdep asserts on i_mutex and cgroup_mutex, and move @d and @parent assignments to their declarations. This patch doesn't introduce any functional difference. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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02ae7486d05ae6df8395409a4945b2420f1e35c2 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: fix harmless bugs in cgroup_load_subsys() fail path and cgroup_unload_subsys() * If idr init fails, cgroup_load_subsys() cleared dummytop->subsys[] before calilng ->destroy() making CSS inaccessible to the callback, and didn't unlink ss->sibling. As no modular controller uses ->use_id, this doesn't cause any actual problems. * cgroup_unload_subsys() was forgetting to free idr, call ->pre_destroy() and clear ->active. As there currently is no modular controller which uses ->use_id, ->pre_destroy() or ->active, this doesn't cause any actual problems. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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648bb56d076bde31113f09a7d24d95bc8d4155ac |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: lock cgroup_mutex in cgroup_init_subsys() Make cgroup_init_subsys() grab cgroup_mutex while initializing a subsystem so that all helpers and callbacks are called under the context they expect. This isn't strictly necessary as cgroup_init_subsys() doesn't race with anybody but will allow adding lockdep assertions. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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b48c6a80a0f7584056f768268fc12b87745a393f |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: trivial cleanup for cgroup_init/load_subsys() Consistently use @css and @dummytop in these two functions instead of referring to them indirectly. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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38b53abaa3e0c7e750ef73eee919cf42eee6b134 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: make CSS_* flags bit masks instead of bit positions Currently, CSS_* flags are defined as bit positions and manipulated using atomic bitops. There's no reason to use atomic bitops for them and bit positions are clunkier to deal with than bit masks. Make CSS_* bit masks instead and use the usual C bitwise operators to access them. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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febfcef60d4f9457785b45aab548bc7ee5ea158f |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup->dentry isn't a RCU pointer cgroup->dentry is marked and used as a RCU pointer; however, it isn't one - the final dentry put doesn't go through call_rcu(). cgroup and dentry share the same RCU freeing rule via synchronize_rcu() in cgroup_diput() (kfree_rcu() used on cgrp is unnecessary). If cgrp is accessible under RCU read lock, so is its dentry and dereferencing cgrp->dentry doesn't need any further RCU protection or annotation. While not being accurate, before the previous patch, the RCU accessors served a purpose as memory barriers - cgroup->dentry used to be assigned after the cgroup was made visible to cgroup_path(), so the assignment and dereferencing in cgroup_path() needed the memory barrier pair. Now that list_add_tail_rcu() happens after cgroup->dentry is assigned, this no longer is necessary. Remove the now unnecessary and misleading RCU annotations from cgroup->dentry. To make up for the removal of rcu_dereference_check() in cgroup_path(), add an explicit rcu_lockdep_assert(), which asserts the dereference rule of @cgrp, not cgrp->dentry. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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4e139afc22cb98d0d032ffce0285bfcc73ca5217 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: create directory before linking while creating a new cgroup While creating a new cgroup, cgroup_create() links the newly allocated cgroup into various places before trying to create its directory. Because cgroup life-cycle is tied to the vfs objects, this makes it impossible to use cgroup_rmdir() for rolling back creation - the removal logic depends on having full vfs objects. This patch moves directory creation above linking and collect linking operations to one place. This allows directory creation failure to share error exit path with css allocation failures and any failure sites afterwards (to be added later) can use cgroup_rmdir() logic to undo creation. Note that this also makes the memory barriers around cgroup->dentry, which currently is misleadingly using RCU operations, unnecessary. This will be handled in the next patch. While at it, locking BUG_ON() on i_mutex is converted to lockdep_assert_held(). v2: Patch originally removed %NULL dentry check in cgroup_path(); however, Li pointed out that this patch doesn't make it unnecessary as ->create() may call cgroup_path(). Drop the change for now. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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28fd6f30ac3efd9170ae1ac89f3521d53b5eb83a |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: open-code cgroup_create_dir() The operation order of cgroup creation is about to change and cgroup_create_dir() is more of a hindrance than a proper abstraction. Open-code it by moving the parent nlink adjustment next to self nlink adjustment in cgroup_create_file() and the rest to cgroup_create(). This patch doesn't introduce any behavior change. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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2243076ad128d0cc196cf6597e6ddcf6bc907676 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: initialize cgrp->allcg_node in init_cgroup_housekeeping() Not strictly necessary but it's annoying to have uninitialized list_head around. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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175431635ec09b1d1bba04979b006b99e8305a83 |
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19-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: remove incorrect dget/dput() pair in cgroup_create_dir() cgroup_create_dir() does weird dancing with dentry refcnt. On success, it gets and then puts it achieving nothing. On failure, it puts but there isn't no matching get anywhere leading to the following oops if cgroup_create_file() fails for whatever reason. ------------[ cut here ]------------ kernel BUG at /work/os/work/fs/dcache.c:552! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: CPU 2 Pid: 697, comm: mkdir Not tainted 3.7.0-rc4-work+ #3 Bochs Bochs RIP: 0010:[<ffffffff811d9c0c>] [<ffffffff811d9c0c>] dput+0x1dc/0x1e0 RSP: 0018:ffff88001a3ebef8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff88000e5b1ef8 RCX: 0000000000000403 RDX: 0000000000000303 RSI: 2000000000000000 RDI: ffff88000e5b1f58 RBP: ffff88001a3ebf18 R08: ffffffff82c76960 R09: 0000000000000001 R10: ffff880015022080 R11: ffd9bed70f48a041 R12: 00000000ffffffea R13: 0000000000000001 R14: ffff88000e5b1f58 R15: 00007fff57656d60 FS: 00007ff05fcb3800(0000) GS:ffff88001fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004046f0 CR3: 000000001315f000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process mkdir (pid: 697, threadinfo ffff88001a3ea000, task ffff880015022080) Stack: ffff88001a3ebf48 00000000ffffffea 0000000000000001 0000000000000000 ffff88001a3ebf38 ffffffff811cc889 0000000000000001 ffff88000e5b1ef8 ffff88001a3ebf68 ffffffff811d1fc9 ffff8800198d7f18 ffff880019106ef8 Call Trace: [<ffffffff811cc889>] done_path_create+0x19/0x50 [<ffffffff811d1fc9>] sys_mkdirat+0x59/0x80 [<ffffffff811d2009>] sys_mkdir+0x19/0x20 [<ffffffff81be1e02>] system_call_fastpath+0x16/0x1b Code: 00 48 8d 90 18 01 00 00 48 89 93 c0 00 00 00 4c 89 a0 18 01 00 00 48 8b 83 a0 00 00 00 83 80 28 01 00 00 01 e8 e6 6f a0 00 eb 92 <0f> 0b 66 90 0f 1f 44 00 00 55 48 89 e5 41 57 41 56 49 89 fe 41 RIP [<ffffffff811d9c0c>] dput+0x1dc/0x1e0 RSP <ffff88001a3ebef8> ---[ end trace 1277bcfd9561ddb0 ]--- Fix it by dropping the unnecessary dget/dput() pair. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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17cf22c33e1f1b5e435469c84e43872579497653 |
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02-Mar-2010 |
Eric W. Biederman <ebiederm@xmission.com> |
pidns: Use task_active_pid_ns where appropriate The expressions tsk->nsproxy->pid_ns and task_active_pid_ns aka ns_of_pid(task_pid(tsk)) should have the same number of cache line misses with the practical difference that ns_of_pid(task_pid(tsk)) is released later in a processes life. Furthermore by using task_active_pid_ns it becomes trivial to write an unshare implementation for the the pid namespace. So I have used task_active_pid_ns everywhere I can. In fork since the pid has not yet been attached to the process I use ns_of_pid, to achieve the same effect. Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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574bd9f7c7c1d32f52dea5488018a6ff79031e22 |
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09-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: implement generic child / descendant walk macros Currently, cgroup doesn't provide any generic helper for walking a given cgroup's children or descendants. This patch adds the following three macros. * cgroup_for_each_child() - walk immediate children of a cgroup. * cgroup_for_each_descendant_pre() - visit all descendants of a cgroup in pre-order tree traversal. * cgroup_for_each_descendant_post() - visit all descendants of a cgroup in post-order tree traversal. All three only require the user to hold RCU read lock during traversal. Verifying that each iterated cgroup is online is the responsibility of the user. When used with proper synchronization, cgroup_for_each_descendant_pre() can be used to propagate state updates to descendants in reliable way. See comments for details. v2: s/config/state/ in commit message and comments per Michal. More documentation on synchronization rules. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujisu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com>
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eb6fd5040ee799009173daa49c3e7aa0362167c9 |
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09-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: use rculist ops for cgroup->children Use RCU safe list operations for cgroup->children. This will be used to implement cgroup children / descendant walking which can be used by controllers. Note that cgroup_create() now puts a new cgroup at the end of the ->children list instead of head. This isn't strictly necessary but is done so that the iteration order is more conventional. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
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a8638030f668884720b8f4456448d0ce33952b05 |
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09-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup_subsys->post_create() Currently, there's no way for a controller to find out whether a new cgroup finished all ->create() allocatinos successfully and is considered "live" by cgroup. This becomes a problem later when we add generic descendants walking to cgroup which can be used by controllers as controllers don't have a synchronization point where it can synchronize against new cgroups appearing in such walks. This patch adds ->post_create(). It's called after all ->create() succeeded and the cgroup is linked into the generic cgroup hierarchy. This plays the counterpart of ->pre_destroy(). When used in combination with the to-be-added generic descendant iterators, ->post_create() can be used to implement reliable state inheritance. It will be explained with the descendant iterators. v2: Added a paragraph about its future use w/ descendant iterators per Michal. v3: Forgot to add ->post_create() invocation to cgroup_load_subsys(). Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
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316eb661f125397d46f16f94e3c81ad3dc4c1233 |
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08-Nov-2012 |
Tao Ma <boyu.mt@taobao.com> |
cgroup: set 'start' with the right value in cgroup_path. 'start' is set to buf + buflen and do the '--' immediately. Just set it to 'buf + buflen - 1' directly. Signed-off-by: Tao Ma <boyu.mt@taobao.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com>
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bcf6de1b9129531215d26dd9af8331e84973bc52 |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: make ->pre_destroy() return void All ->pre_destory() implementations return 0 now, which is the only allowed return value. Make it return void. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Vivek Goyal <vgoyal@redhat.com>
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b25ed609d0eecf077db607e88ea70bae83b6adb2 |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: remove CGRP_WAIT_ON_RMDIR, cgroup_exclude_rmdir() and cgroup_release_and_wakeup_rmdir() CGRP_WAIT_ON_RMDIR is another kludge which was added to make cgroup destruction rollback somewhat working. cgroup_rmdir() used to drain CSS references and CGRP_WAIT_ON_RMDIR and the associated waitqueue and helpers were used to allow the task performing rmdir to wait for the next relevant event. Unfortunately, the wait is visible to controllers too and the mechanism got exposed to memcg by 887032670d ("cgroup avoid permanent sleep at rmdir"). Now that the draining and retries are gone, CGRP_WAIT_ON_RMDIR is unnecessary. Remove it and all the mechanisms supporting it. Note that memcontrol.c changes are essentially revert of 887032670d ("cgroup avoid permanent sleep at rmdir"). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Balbir Singh <bsingharora@gmail.com>
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1a90dd508b0b00e382fd61a46f55dc889ac21b39 |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: deactivate CSS's and mark cgroup dead before invoking ->pre_destroy() Because ->pre_destroy() could fail and can't be called under cgroup_mutex, cgroup destruction did something very ugly. 1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise. 2. Release cgroup_mutex and call ->pre_destroy(). 3. Re-grab cgroup_mutex and verify it can still be destroyed; fail otherwise. 4. Continue destroying. In addition to being ugly, it has been always broken in various ways. For example, memcg ->pre_destroy() expects the cgroup to be inactive after it's done but tasks can be attached and detached between #2 and #3 and the conditions that memcg verified in ->pre_destroy() might no longer hold by the time control reaches #3. Now that ->pre_destroy() is no longer allowed to fail. We can switch to the following. 1. Grab cgroup_mutex and verify it can be destroyed; fail otherwise. 2. Deactivate CSS's and mark the cgroup removed thus preventing any further operations which can invalidate the verification from #1. 3. Release cgroup_mutex and call ->pre_destroy(). 4. Re-grab cgroup_mutex and continue destroying. After this change, controllers can safely assume that ->pre_destroy() will only be called only once for a given cgroup and, once ->pre_destroy() is called, the cgroup will stay dormant till it's destroyed. This removes the only reason ->pre_destroy() can fail - new task being attached or child cgroup being created inbetween. Error out path is removed and ->pre_destroy() invocation is open coded in cgroup_rmdir(). v2: cgroup_call_pre_destroy() removal moved to this patch per Michal. Commit message updated per Glauber. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Glauber Costa <glommer@parallels.com>
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976c06bcccc50573997609fa7ec842479bd96ffb |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: use cgroup_lock_live_group(parent) in cgroup_create() This patch makes cgroup_create() fail if @parent is marked removed. This is to prepare for further updates to cgroup_rmdir() path. Note that this change isn't strictly necessary. cgroup can only be created via mkdir and the removed marking and dentry removal happen without releasing cgroup_mutex, so cgroup_create() can never race with cgroup_rmdir(). Even after the scheduled updates to cgroup_rmdir(), cgroup_mkdir() and cgroup_rmdir() are synchronized by i_mutex rendering the added liveliness check unnecessary. Do it anyway such that locking is contained inside cgroup proper and we don't get nasty surprises if we ever grow another caller of cgroup_create(). Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
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e93160803ffda2e67d9ff9cacb63bb6868c8398f |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: kill CSS_REMOVED CSS_REMOVED is one of the several contortions which were necessary to support css reference draining on cgroup removal. All css->refcnts which need draining should be deactivated and verified to equal zero atomically w.r.t. css_tryget(). If any one isn't zero, all refcnts needed to be re-activated and css_tryget() shouldn't fail in the process. This was achieved by letting css_tryget() busy-loop until either the refcnt is reactivated (failed removal attempt) or CSS_REMOVED is set (committing to removal). Now that css refcnt draining is no longer used, there's no need for atomic rollback mechanism. css_tryget() simply can look at the reference count and fail if it's deactivated - it's never getting re-activated. This patch removes CSS_REMOVED and updates __css_tryget() to fail if the refcnt is deactivated. As deactivation and removal are a single step now, they no longer need to be protected against css_tryget() happening from irq context. Remove local_irq_disable/enable() from cgroup_rmdir(). Note that this removes css_is_removed() whose only user is VM_BUG_ON() in memcontrol.c. We can replace it with a check on the refcnt but given that the only use case is a debug assert, I think it's better to simply unexport it. v2: Comment updated and explanation on local_irq_disable/enable() added per Michal Hocko. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com>
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ed95779340b50e362245c81b5dec0d11a1debfa8 |
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05-Nov-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs 2ef37d3fe4 ("memcg: Simplify mem_cgroup_force_empty_list error handling") removed the last user of __DEPRECATED_clear_css_refs. This patch removes __DEPRECATED_clear_css_refs and mechanisms to support it. * Conditionals dependent on __DEPRECATED_clear_css_refs removed. * cgroup_clear_css_refs() can no longer fail. All that needs to be done are deactivating refcnts, setting CSS_REMOVED and putting the base reference on each css. Remove cgroup_clear_css_refs() and the failure path, and open-code the loops into cgroup_rmdir(). This patch keeps the two for_each_subsys() loops separate while open coding them. They can be merged now but there are scheduled changes which need them to be separate, so keep them separate to reduce the amount of churn. local_irq_save/restore() from cgroup_clear_css_refs() are replaced with local_irq_disable/enable() for simplicity. This is safe as cgroup_rmdir() is always called with IRQ enabled. Note that this IRQ switching is necessary to ensure that css_tryget() isn't called from IRQ context on the same CPU while lower context is between CSS deactivation and setting CSS_REMOVED as css_tryget() would hang forever in such cases waiting for CSS to be re-activated or CSS_REMOVED set. This will go away soon. v2: cgroup_call_pre_destroy() removal dropped per Michal. Commit message updated to explain local_irq_disable/enable() conversion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizefan@huawei.com>
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d87838321124061f6c935069d97f37010fa417e6 |
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19-Oct-2012 |
Tejun Heo <tj@kernel.org> |
Revert "cgroup: Remove task_lock() from cgroup_post_fork()" This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan <lizefan@huawei.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable@vger.kernel.org
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9bb71308b8133d643648776243e4d5599b1c193d |
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19-Oct-2012 |
Tejun Heo <tj@kernel.org> |
Revert "cgroup: Drop task_lock(parent) on cgroup_fork()" This reverts commit 7e381b0eb1e1a9805c37335562e8dc02e7d7848c. The commit incorrectly assumed that fork path always performed threadgroup_change_begin/end() and depended on that for synchronization against task exit and cgroup migration paths instead of explicitly grabbing task_lock(). threadgroup_change is not locked when forking a new process (as opposed to a new thread in the same process) and even if it were it wouldn't be effective as different processes use different threadgroup locks. Revert the incorrect optimization. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <20121008020000.GB2575@localhost> Acked-by: Li Zefan <lizefan@huawei.com> Bitterly-Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable@vger.kernel.org
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1f5320d5972aa50d3e8d2b227b636b370e608359 |
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04-Oct-2012 |
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> |
cgroup: notify_on_release may not be triggered in some cases notify_on_release must be triggered when the last process in a cgroup is move to another. But if the first(and only) process in a cgroup is moved to another, notify_on_release is not triggered. # mkdir /cgroup/cpu/SRC # mkdir /cgroup/cpu/DST # # echo 1 >/cgroup/cpu/SRC/notify_on_release # echo 1 >/cgroup/cpu/DST/notify_on_release # # sleep 300 & [1] 8629 # # echo 8629 >/cgroup/cpu/SRC/tasks # echo 8629 >/cgroup/cpu/DST/tasks -> notify_on_release for /SRC must be triggered at this point, but it isn't. This is because put_css_set() is called before setting CGRP_RELEASABLE in cgroup_task_migrate(), and is a regression introduce by the commit:74a1166d(cgroups: make procs file writable), which was merged into v3.0. Cc: Ben Blum <bblum@andrew.cmu.edu> Cc: <stable@vger.kernel.org> # v3.0.x and later Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Tejun Heo <tj@kernel.org>
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5edee61edeaaebafe584f8fb7074c1ef4658596b |
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17-Oct-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_subsys->fork() should be called after the task is added to css_set cgroup core has a bug which violates a basic rule about event notifications - when a new entity needs to be added, you add that to the notification list first and then make the new entity conform to the current state. If done in the reverse order, an event happening inbetween will be lost. cgroup_subsys->fork() is invoked way before the new task is added to the css_set. Currently, cgroup_freezer is the only user of ->fork() and uses it to make new tasks conform to the current state of the freezer. If FROZEN state is requested while fork is in progress between cgroup_fork_callbacks() and cgroup_post_fork(), the child could escape freezing - the cgroup isn't frozen when ->fork() is called and the freezer couldn't see the new task on the css_set. This patch moves cgroup_subsys->fork() invocation to cgroup_post_fork() after the new task is added to the css_set. cgroup_fork_callbacks() is removed. Because now a task may be migrated during cgroup_subsys->fork(), freezer_fork() is updated so that it adheres to the usual RCU locking and the rather pointless comment on why locking can be different there is removed (if it doesn't make anything simpler, why even bother?). Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: stable@vger.kernel.org
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8c7f6edbda01f1b1a2e60ad61f14fe38023e433b |
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13-Sep-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them Currently, cgroup hierarchy support is a mess. cpu related subsystems behave correctly - configuration, accounting and control on a parent properly cover its children. blkio and freezer completely ignore hierarchy and treat all cgroups as if they're directly under the root cgroup. Others show yet different behaviors. These differing interpretations of cgroup hierarchy make using cgroup confusing and it impossible to co-mount controllers into the same hierarchy and obtain sane behavior. Eventually, we want full hierarchy support from all subsystems and probably a unified hierarchy. Users using separate hierarchies expecting completely different behaviors depending on the mounted subsystem is deterimental to making any progress on this front. This patch adds cgroup_subsys.broken_hierarchy and sets it to %true for controllers which are lacking in hierarchy support. The goal of this patch is two-fold. * Move users away from using hierarchy on currently non-hierarchical subsystems, so that implementing proper hierarchy support on those doesn't surprise them. * Keep track of which controllers are broken how and nudge the subsystems to implement proper hierarchy support. For now, start with a single warning message. We can whine louder later on. v2: Fixed a typo spotted by Michal. Warning message updated. v3: Updated memcg part so that it doesn't generate warning in the cases where .use_hierarchy=false doesn't make the behavior different from root.use_hierarchy=true. Fixed a typo spotted by Glauber. v4: Check ->broken_hierarchy after cgroup creation is complete so that ->create() can affect the result per Michal. Dropped unnecessary memcg root handling per Michal. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Turner <pjt@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Thomas Graf <tgraf@suug.ch> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Neil Horman <nhorman@tuxdriver.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
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8a8e04df4747661daaee77e98e102d99c9e09b98 |
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12-Sep-2012 |
Daniel Wagner <daniel.wagner@bmw-carit.de> |
cgroup: Assign subsystem IDs during compile time WARNING: With this change it is impossible to load external built controllers anymore. In case where CONFIG_NETPRIO_CGROUP=m and CONFIG_NET_CLS_CGROUP=m is set, corresponding subsys_id should also be a constant. Up to now, net_prio_subsys_id and net_cls_subsys_id would be of the type int and the value would be assigned during runtime. By switching the macro definition IS_SUBSYS_ENABLED from IS_BUILTIN to IS_ENABLED, all *_subsys_id will have constant value. That means we need to remove all the code which assumes a value can be assigned to net_prio_subsys_id and net_cls_subsys_id. A close look is necessary on the RCU part which was introduces by following patch: commit f845172531fb7410c7fb7780b1a6e51ee6df7d52 Author: Herbert Xu <herbert@gondor.apana.org.au> Mon May 24 09:12:34 2010 Committer: David S. Miller <davem@davemloft.net> Mon May 24 09:12:34 2010 cls_cgroup: Store classid in struct sock Tis code was added to init_cgroup_cls() /* We can't use rcu_assign_pointer because this is an int. */ smp_wmb(); net_cls_subsys_id = net_cls_subsys.subsys_id; respectively to exit_cgroup_cls() net_cls_subsys_id = -1; synchronize_rcu(); and in module version of task_cls_classid() rcu_read_lock(); id = rcu_dereference(net_cls_subsys_id); if (id >= 0) classid = container_of(task_subsys_state(p, id), struct cgroup_cls_state, css)->classid; rcu_read_unlock(); Without an explicit explaination why the RCU part is needed. (The rcu_deference was fixed by exchanging it to rcu_derefence_index_check() in a later commit, but that is a minor detail.) So here is my pondering why it was introduced and why it safe to remove it now. Note that this code was copied over to net_prio the reasoning holds for that subsystem too. The idea behind the RCU use for net_cls_subsys_id is to make sure we get a valid pointer back from task_subsys_state(). task_subsys_state() is just blindly accessing the subsys array and returning the pointer. Obviously, passing in -1 as id into task_subsys_state() returns an invalid value (out of lower bound). So this code makes sure that only after module is loaded and the subsystem registered, the id is assigned. Before unregistering the module all old readers must have left the critical section. This is done by assigning -1 to the id and issuing a synchronized_rcu(). Any new readers wont call task_subsys_state() anymore and therefore it is safe to unregister the subsystem. The new code relies on the same trick, but it looks at the subsys pointer return by task_subsys_state() (remember the id is constant and therefore we allways have a valid index into the subsys array). No precautions need to be taken during module loading module. Eventually, all CPUs will get a valid pointer back from task_subsys_state() because rebind_subsystem() which is called after the module init() function will assigned subsys[net_cls_subsys_id] the newly loaded module subsystem pointer. When the subsystem is about to be removed, rebind_subsystem() will called before the module exit() function. In this case, rebind_subsys() will assign subsys[net_cls_subsys_id] a NULL pointer and then it calls synchronize_rcu(). All old readers have left by then the critical section. Any new reader wont access the subsystem anymore. At this point we are safe to unregister the subsystem. No synchronize_rcu() call is needed. Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: netdev@vger.kernel.org Cc: cgroups@vger.kernel.org
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80f4c87774721e864d5a5a1f7aca3e95fd90e194 |
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12-Sep-2012 |
Daniel Wagner <daniel.wagner@bmw-carit.de> |
cgroup: Do not depend on a given order when populating the subsys array The *_subsys_id will be used as index to access the subsys. Therefore we need to care we populate the subsystem at the correct position by using designated initialization. With this change we are able to interleave builtin and modules in the subsys array. Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: netdev@vger.kernel.org Cc: cgroups@vger.kernel.org
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5fc0b02544b3b9bd3db5a8156b5f3e7350f8e797 |
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12-Sep-2012 |
Daniel Wagner <daniel.wagner@bmw-carit.de> |
cgroup: Wrap subsystem selection macro Before we are able to define all subsystem ids at compile time we need a more fine grained control what gets defined when we include cgroup_subsys.h. For example we define the enums for the subsystems or to declare for struct cgroup_subsys (builtin subsystem) by including cgroup_subsys.h and defining SUBSYS accordingly. Currently, the decision if a subsys is used is defined inside the header by testing if CONFIG_*=y is true. By moving this test outside of cgroup_subsys.h we are able to control it on the include level. This is done by introducing IS_SUBSYS_ENABLED which then is defined according the task, e.g. is CONFIG_*=y or CONFIG_*=m. Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: netdev@vger.kernel.org Cc: cgroups@vger.kernel.org
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be45c900fdc2c66baad5a7703fb8136991d88aeb |
|
13-Sep-2012 |
Daniel Wagner <daniel.wagner@bmw-carit.de> |
cgroup: Remove CGROUP_BUILTIN_SUBSYS_COUNT CGROUP_BUILTIN_SUBSYS_COUNT is used as start index or stop index when looping over the subsys array looking either at the builtin or the module subsystems. Since all the builtin subsystems have an id which is lower then CGROUP_BUILTIN_SUBSYS_COUNT we know that any module will have an id larger than CGROUP_BUILTIN_SUBSYS_COUNT. In short the ids are sorted. We are about to change id assignment to happen only at compile time later in this series. That means we can't rely on the above trick since all ids will always be defined at compile time. Furthermore, ordering the builtin subsystems and the module subsystems is not really necessary. So we need a different way to know which subsystem is a builtin or a module one. We can use the subsys[]->module pointer for this. Any place where we need to know if a subsys is module we just check for the pointer. If it is NULL then the subsystem is a builtin one. With this we are able to drop the CGROUP_BUILTIN_SUBSYS_COUNT enum. Though we need to introduce a temporary placeholder so that we don't get a compilation error when only CONFIG_CGROUP is selected and no single controller. An empty enum definition is not valid. Later in this series we are able to remove the placeholder again. And with this change we get a fix for this: kernel/cgroup.c: In function ‘cgroup_load_subsys’: kernel/cgroup.c:4326:38: warning: array subscript is below array bounds [-Warray-bounds] when CONFIG_CGROUP=y and no built in controller was enabled. Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Cc: Gao feng <gaofeng@cn.fujitsu.com> Cc: Jamal Hadi Salim <jhs@mojatatu.com> Cc: John Fastabend <john.r.fastabend@intel.com> Cc: netdev@vger.kernel.org Cc: cgroups@vger.kernel.org
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a1a71b45a66fd3c3c453b55fbd180f8fccdd1daa |
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23-Aug-2012 |
Aristeu Rozanski <aris@redhat.com> |
cgroup: rename subsys_bits to subsys_mask In a previous discussion, Tejun Heo suggested to rename references to subsys_bits (added_bits, removed_bits, etc) by something more meaningful. Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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03b1cde6b22f625ae832b939bc7379ec1466aec5 |
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23-Aug-2012 |
Aristeu Rozanski <aris@redhat.com> |
cgroup: add xattr support This is one of the items in the plumber's wish list. For use cases: >> What would the use case be for this? > > Attaching meta information to services, in an easily discoverable > way. For example, in systemd we create one cgroup for each service, and > could then store data like the main pid of the specific service as an > xattr on the cgroup itself. That way we'd have almost all service state > in the cgroupfs, which would make it possible to terminate systemd and > later restart it without losing any state information. But there's more: > for example, some very peculiar services cannot be terminated on > shutdown (i.e. fakeraid DM stuff) and it would be really nice if the > services in question could just mark that on their cgroup, by setting an > xattr. On the more desktopy side of things there are other > possibilities: for example there are plans defining what an application > is along the lines of a cgroup (i.e. an app being a collection of > processes). With xattrs one could then attach an icon or human readable > program name on the cgroup. > > The key idea is that this would allow attaching runtime meta information > to cgroups and everything they model (services, apps, vms), that doesn't > need any complex userspace infrastructure, has good access control > (i.e. because the file system enforces that anyway, and there's the > "trusted." xattr namespace), notifications (inotify), and can easily be > shared among applications. > > Lennart v7: - no changes v6: - remove user xattr namespace, only allow trusted and security v5: - check for capabilities before setting/removing xattrs v4: - no changes v3: - instead of config option, use mount option to enable xattr support Original-patch-by: Li Zefan <lizefan@huawei.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Tejun Heo <tj@kernel.org> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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13af07df9b7e49f1987cf36aa048dc6c49d0f93d |
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23-Aug-2012 |
Aristeu Rozanski <aris@redhat.com> |
cgroup: revise how we re-populate root directory When remounting cgroupfs with some subsystems added to it and some removed, cgroup will remove all the files in root directory and then re-popluate it. What I'm doing here is, only remove files which belong to subsystems that are to be unbinded, and only create files for newly-added subsystems. The purpose is to have all other files untouched. This is a preparation for cgroup xattr support. v7: - checkpatch warnings fixed v6: - no changes v5: - no changes v4: - refactored cgroup_clear_directory() to not use cgroup_rm_file() - instead of going thru the list of files, get the file list using the subsystems - use 'subsys_mask' instead of {added,removed}_bits and made cgroup_populate_dir() to match the parameters with cgroup_clear_directory() v3: - refresh patches after recent refactoring Original-patch-by: Li Zefan <lizefan@huawei.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Hugh Dickins <hughd@google.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lennart Poettering <lpoetter@redhat.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Aristeu Rozanski <aris@redhat.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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9249e17fe094d853d1ef7475dd559a2cc7e23d42 |
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25-Jun-2012 |
David Howells <dhowells@redhat.com> |
VFS: Pass mount flags to sget() Pass mount flags to sget() so that it can use them in initialising a new superblock before the set function is called. They could also be passed to the compare function. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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00cd8dd3bf95f2cc8435b4cac01d9995635c6d0b |
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10-Jun-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
stop passing nameidata to ->lookup() Just the flags; only NFS cares even about that, but there are legitimate uses for such argument. And getting rid of that completely would require splitting ->lookup() into a couple of methods (at least), so let's leave that alone for now... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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ce27e317ba22b359bde02216afab934dac3af095 |
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03-Jul-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_rm_files() was calling simple_unlink() with the wrong inode While refactoring cgroup file removal path, 05ef1d7c4a "cgroup: introduce struct cfent" incorrectly changed the @dir argument of simple_unlink() to the inode of the file being deleted instead of that of the containing directory. The effect of this bug is minor - ctime and mtime of the parent weren't properly updated on file deletion. Fix it by using @cgrp->dentry->d_inode instead. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Acked-by: Li Zefan <lizefan@huawei.com> Cc: stable@vger.kernel.org
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5db9a4d99b0157a513944e9a44d29c9cec2e91dc |
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08-Jul-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: fix cgroup hierarchy umount race 48ddbe1946 "cgroup: make css->refcnt clearing on cgroup removal optional" allowed a css to linger after the associated cgroup is removed. As a css holds a reference on the cgroup's dentry, it means that cgroup dentries may linger for a while. Destroying a superblock which has dentries with positive refcnts is a critical bug and triggers BUG() in vfs code. As each cgroup dentry holds an s_active reference, any lingering cgroup has both its dentry and the superblock pinned and thus preventing premature release of superblock. Unfortunately, after 48ddbe1946, there's a small window while releasing a cgroup which is directly under the root of the hierarchy. When a cgroup directory is released, vfs layer first deletes the corresponding dentry and then invokes dput() on the parent, which may recurse further, so when a cgroup directly below root cgroup is released, the cgroup is first destroyed - which releases the s_active it was holding - and then the dentry for the root cgroup is dput(). This creates a window where the root dentry's refcnt isn't zero but superblock's s_active is. If umount happens before or during this window, vfs will see the root dentry with non-zero refcnt and trigger BUG(). Before 48ddbe1946, this problem didn't exist because the last dentry reference was guaranteed to be put synchronously from rmdir(2) invocation which holds s_active around the whole process. Fix it by holding an extra superblock->s_active reference across dput() from css release, which is the dput() path added by 48ddbe1946 and the only one which doesn't hold an extra s_active ref across the final cgroup dput(). Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <4FEEA5CB.8070809@huawei.com> Reported-by: shyju pv <shyju.pv@huawei.com> Tested-by: shyju pv <shyju.pv@huawei.com> Cc: Sasha Levin <levinsasha928@gmail.com> Acked-by: Li Zefan <lizefan@huawei.com>
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7db5b3ca0ecdb2e8fad52a4770e4e320e61c77a6 |
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08-Jul-2012 |
Tejun Heo <tj@kernel.org> |
Revert "cgroup: superblock can't be released with active dentries" This reverts commit fa980ca87d15bb8a1317853f257a505990f3ffde. The commit was an attempt to fix a race condition where a cgroup hierarchy may be unmounted with positive dentry reference on root cgroup. While the commit made the race condition slightly more difficult to trigger, the race was still there and could be reliably triggered using a different test case. Revert the incorrect fix. The next commit will describe the race and fix it correctly. Signed-off-by: Tejun Heo <tj@kernel.org> LKML-Reference: <4FEEA5CB.8070809@huawei.com> Reported-by: shyju pv <shyju.pv@huawei.com> Cc: Sasha Levin <levinsasha928@gmail.com> Acked-by: Li Zefan <lizefan@huawei.com>
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8e3bbf42c6d73881956863cc3305456afe2bc4ea |
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14-Jun-2012 |
Salman Qazi <sqazi@google.com> |
cgroups: Account for CSS_DEACT_BIAS in __css_put When we fixed the race between atomic_dec and css_refcnt, we missed the fact that css_refcnt internally subtracts CSS_DEACT_BIAS to get the actual reference count. This can potentially cause a refcount leak if __css_put races with cgroup_clear_css_refs. Signed-off-by: Salman Qazi <sqazi@google.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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6be96a5c905178637ec06a5d456a76b2b304fca3 |
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07-Jun-2012 |
Li Zefan <lizefan@huawei.com> |
cgroup: remove hierarchy_mutex It was introduced for memcg to iterate cgroup hierarchy without holding cgroup_mutex, but soon after that it was replaced with a lockless way in memcg. No one used hierarchy_mutex since that, so remove it. Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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967db0ea65b0bf8507a7643ac8f296c4f2c0a834 |
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07-Jun-2012 |
Salman Qazi <sqazi@google.com> |
cgroup: make sure that decisions in __css_put are atomic __css_put is using atomic_dec on the ref count, and then looking at the ref count to make decisions. This is prone to races, as someone else may decrement ref count between our decrement and our decision. Instead, we should base our decisions on the value that we decremented the ref count to. (This results in an actual race on Google's kernel which I haven't been able to reproduce on the upstream kernel. Having said that, it's still incorrect by inspection). Signed-off-by: Salman Qazi <sqazi@google.com> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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91c63734f6908425903aed69c04035592f18d398 |
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30-May-2012 |
Johannes Weiner <hannes@cmpxchg.org> |
kernel: cgroup: push rcu read locking from css_is_ancestor() to callsite Library functions should not grab locks when the callsites can do it, even if the lock nests like the rcu read-side lock does. Push the rcu_read_lock() from css_is_ancestor() to its single user, mem_cgroup_same_or_subtree() in preparation for another user that may already hold the rcu read-side lock. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fa980ca87d15bb8a1317853f257a505990f3ffde |
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24-May-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: superblock can't be released with active dentries 48ddbe1946 "cgroup: make css->refcnt clearing on cgroup removal optional" allowed a css to linger after the associated cgroup is removed. As a css holds a reference on the cgroup's dentry, it means that cgroup dentries may linger for a while. cgroup_create() does grab an active reference on the superblock to prevent it from going away while there are !root cgroups; however, the reference is put from cgroup_diput() which is invoked on cgroup removal, so cgroup dentries which are removed but persisting due to lingering csses already have released their superblock active refs allowing superblock to be killed while those dentries are around. Given the right condition, this makes cgroup_kill_sb() call kill_litter_super() with dentries with non-zero d_count leading to BUG() in shrink_dcache_for_umount_subtree(). Fix it by adding cgroup_dops->d_release() operation and moving deactivate_super() to it. cgroup_diput() now marks dentry->d_fsdata with itself if superblock should be deactivated and cgroup_d_release() deactivates the superblock on dentry release. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Sasha Levin <levinsasha928@gmail.com> Tested-by: Sasha Levin <levinsasha928@gmail.com> LKML-Reference: <CA+1xoqe5hMuxzCRhMy7J0XchDk2ZnuxOHJKikROk1-ReAzcT6g@mail.gmail.com> Acked-by: Li Zefan <lizefan@huawei.com>
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14a590c3f987977d7b09ec926481ee0238c08eee |
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12-Mar-2012 |
Eric W. Biederman <ebiederm@xmission.com> |
userns: Convert cgroup permission checks to use uid_eq Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
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c4c27fbdda4e8ba87806c415b6d15266b07bce4b |
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21-Apr-2012 |
Mike Galbraith <mgalbraith@suse.de> |
cgroups: disallow attaching kthreadd or PF_THREAD_BOUND threads Allowing kthreadd to be moved to a non-root group makes no sense, it being a global resource, and needlessly leads unsuspecting users toward trouble. 1. An RT workqueue worker thread spawned in a task group with no rt_runtime allocated is not schedulable. Simple user error, but harmful to the box. 2. A worker thread which acquires PF_THREAD_BOUND can never leave a cpuset, rendering the cpuset immortal. Save the user some unexpected trouble, just say no. Signed-off-by: Mike Galbraith <mgalbraith@suse.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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86f82d561864e902c70282b6f17cf590c0f34691 |
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10-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_subsys->populate() With memcg converted, cgroup_subsys->populate() doesn't have any user left. Remove it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com>
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48ddbe194623ae089cc0576e60363f2d2e85662a |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: make css->refcnt clearing on cgroup removal optional Currently, cgroup removal tries to drain all css references. If there are active css references, the removal logic waits and retries ->pre_detroy() until either all refs drop to zero or removal is cancelled. This semantics is unusual and adds non-trivial complexity to cgroup core and IMHO is fundamentally misguided in that it couples internal implementation details (references to internal data structure) with externally visible operation (rmdir). To userland, this is a behavior peculiarity which is unnecessary and difficult to expect (css refs is otherwise invisible from userland), and, to policy implementations, this is an unnecessary restriction (e.g. blkcg wants to hold css refs for caching purposes but can't as that becomes visible as rmdir hang). Unfortunately, memcg currently depends on ->pre_destroy() retrials and cgroup removal vetoing and can't be immmediately switched to the new behavior. This patch introduces the new behavior of not waiting for css refs to drain and maintains the old behavior for subsystems which have __DEPRECATED_clear_css_refs set. Once, memcg is updated, we can drop the code paths for the old behavior as proposed in the following patch. Note that the following patch is incorrect in that dput work item is in cgroup and may lose some of dputs when multiples css's are released back-to-back, and __css_put() triggers check_for_release() when refcnt reaches 0 instead of 1; however, it shows what part can be removed. http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251 Note that, in not-too-distant future, cgroup core will start emitting warning messages for subsys which require the old behavior, so please get moving. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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28b4c27b8e6bb6d7ff2875281a8484f8898a87ef |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: use negative bias on css->refcnt to block css_tryget() When a cgroup is about to be removed, cgroup_clear_css_refs() is called to check and ensure that there are no active css references. This is currently achieved by dropping the refcnt to zero iff it has only the base ref. If all css refs could be dropped to zero, ref clearing is successful and CSS_REMOVED is set on all css. If not, the base ref is restored. While css ref is zero w/o CSS_REMOVED set, any css_tryget() attempt on it busy loops so that they are atomic w.r.t. the whole css ref clearing. This does work but dropping and re-instating the base ref is somewhat hairy and makes it difficult to add more logic to the put path as there are two of them - the regular css_put() and the reversible base ref clearing. This patch updates css ref clearing such that blocking new css_tryget() and putting the base ref are separate operations. CSS_DEACT_BIAS, defined as INT_MIN, is added to css->refcnt and css_tryget() busy loops while refcnt is negative. After all css refs are deactivated, if they were all one, ref clearing succeeded and CSS_REMOVED is set and the base ref is put using the regular css_put(); otherwise, CSS_DEACT_BIAS is subtracted from the refcnts and the original postive values are restored. css_refcnt() accessor which always returns the unbiased positive reference counts is added and used to simplify refcnt usages. While at it, relocate and reformat comments in cgroup_has_css_refs(). This separates css->refcnt deactivation and putting the base ref, which enables the next patch to make ref clearing optional. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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79578621b4847afdef48d19a28d00e3b188c37e1 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_rm_cftypes() Implement cgroup_rm_cftypes() which removes an array of cftypes from a subsystem. It can be called whether the target subsys is attached or not. cgroup core will remove the specified file from all existing cgroups. This will be used to improve sub-subsys modularity and will be helpful for unified hierarchy. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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05ef1d7c4a5b6d09cadd2b8e9b3c395363d1a89c |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce struct cfent This patch adds cfent (cgroup file entry) which is the association between a cgroup and a file. This is in-cgroup representation of files under a cgroup directory. This simplifies walking walking cgroup files and thus cgroup_clear_directory(), which is now implemented in two parts - cgroup_rm_file() and a loop around it. cgroup_rm_file() will be used to implement cftype removal and cfent is scheduled to serve cgroup specific per-file data (e.g. for sysfs-like "sever" semantics). v2: - cfe was freed from cgroup_rm_file() which led to use-after-free if the file had openers at the time of removal. Moved to cgroup_diput(). - cgroup_clear_directory() triggered WARN_ON_ONCE() if d_subdirs wasn't empty after removing all files. This triggered spuriously if some files were open during directory clearing. Removed. v3: - In cgroup_diput(), WARN_ONCE(!list_empty(&cfe->node)) could be spuriously triggered for root cgroups because they don't go through cgroup_clear_directory() on unmount. Don't trigger WARN for root cgroups. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Glauber Costa <glommer@parallels.com>
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f6ea93723d0049ae5fbbb5292cb10c51d7a80801 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate __d_cgrp() and __d_cft() Move the two macros upwards as they'll be used earlier in the file. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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db0416b64977cb0f382175608286cc80c7573e38 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: remove cgroup_add_file[s]() No controller is using cgroup_add_files[s](). Unexport them, and convert cgroup_add_files() to handle NULL entry terminated array instead of taking count explicitly and continue creation on failure for internal use. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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4baf6e33251b37f111e21289f8ee71fe4cce236e |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: convert all non-memcg controllers to the new cftype interface Convert debug, freezer, cpuset, cpu_cgroup, cpuacct, net_prio, blkio, net_cls and device controllers to use the new cftype based interface. Termination entry is added to cftype arrays and populate callbacks are replaced with cgroup_subsys->base_cftypes initializations. This is functionally identical transformation. There shouldn't be any visible behavior change. memcg is rather special and will be converted separately. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Vivek Goyal <vgoyal@redhat.com>
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6e6ff25bd548a0c5bf5163e4f63e2793dcefbdcb |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: merge cft_release_agent cftype array into the base files array Now that cftype can express whether a file should only be on root, cft_release_agent can be merged into the base files cftypes array. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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8e3f6541d45e1a002801e56a19530a90f775deba |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: implement cgroup_add_cftypes() and friends Currently, cgroup directories are populated by subsys->populate() callback explicitly creating files on each cgroup creation. This level of flexibility isn't needed or desirable. It provides largely unused flexibility which call for abuses while severely limiting what the core layer can do through the lack of structure and conventions. Per each cgroup file type, the only distinction that cgroup users is making is whether a cgroup is root or not, which can easily be expressed with flags. This patch introduces cgroup_add_cftypes(). These deal with cftypes instead of individual files - controllers indicate that certain types of files exist for certain subsystem. Newly added CFTYPE_*_ON_ROOT flags indicate whether a cftype should be excluded or created only on the root cgroup. cgroup_add_cftypes() can be called any time whether the target subsystem is currently attached or not. cgroup core will create files on the existing cgroups as necessary. Also, cgroup_subsys->base_cftypes is added to ease registration of the base files for the subsystem. If non-NULL on subsys init, the cftypes pointed to by ->base_cftypes are automatically registered on subsys init / load. Further patches will convert the existing users and remove the file based interface. Note that this interface allows dynamic addition of files to an active controller. This will be used for sub-controller modularity and unified hierarchy in the longer term. This patch implements the new mechanism but doesn't apply it to any user. v2: replaced DECLARE_CGROUP_CFTYPES[_COND]() with cgroup_subsys->base_cftypes, which works better for cgroup_subsys which is loaded as module. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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b0ca5a84fc3ad8f75bb2b7ac3dc6a77151cd3906 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: build list of all cgroups under a given cgroupfs_root Build a list of all cgroups anchored at cgroupfs_root->allcg_list and going through cgroup->allcg_node. The list is protected by cgroup_mutex and will be used to improve cgroup file handling. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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ff4c8d503e2583b485da46d0ec3dcc29639ab889 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: move cgroup_clear_directory() call out of cgroup_populate_dir() cgroup_populate_dir() currently clears all files and then repopulate the directory; however, the clearing part is only useful when it's called from cgroup_remount(). Relocate the invocation to cgroup_remount(). This is to prepare for further cgroup file handling updates. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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8b5a5a9dbca914d1f7d70276024d1525a3c94081 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: deprecate remount option changes This patch marks the following features for deprecation. * Rebinding subsys by remount: Never reached useful state - only works on empty hierarchies. * release_agent update by remount: release_agent itself will be replaced with conventional fsnotify notification. v2: Lennart pointed out that "name=" is necessary for mounts w/o any controller attached. Drop "name=" deprecation. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Lennart Poettering <mzxreary@0pointer.de>
|
8f121918f2e49f852de1acdc5255cc1ef440d85b |
|
30-Mar-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: cgroup_attach_task() could return -errno after success 61d1d219c4 "cgroup: remove extra calls to find_existing_css_set" made cgroup_task_migrate() return void. An unfortunate side effect was that cgroup_attach_task() was depending on that function's return value to clear its @retval on the success path. On cgroup mounts without any subsystem with ->can_attach() callback, cgroup_attach_task() ended up returning @retval without initializing it on success. For some reason, gcc failed to warn about it and it didn't cause cgroup_attach_task() to return non-zero value in many cases, probably due to difference in register allocation. When the problem materializes, systemd fails to populate /systemd cgroup mount and fails to boot. Fix it by initializing @retval to zero on declaration. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Jiri Kosina <jkosina@suse.cz> LKML-Reference: <alpine.LNX.2.00.1203282354440.25526@pobox.suse.cz> Reviewed-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizefan@huawei.com>
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ca464d69b19120a826aa2534de2511a6f542edf5 |
|
22-Mar-2012 |
Hugh Dickins <hughd@google.com> |
memcg: let css_get_next() rely upon rcu_read_lock() Remove lock and unlock around css_get_next()'s call to idr_get_next(). memcg iterators (only users of css_get_next) already did rcu_read_lock(), and its comment demands that; but add a WARN_ON_ONCE to make sure of it. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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42aee6c495e07dba7410b863a360db6bb9ec6d66 |
|
22-Mar-2012 |
Hugh Dickins <hughd@google.com> |
cgroup: revert ss_id_lock to spinlock Commit c1e2ee2dc436 ("memcg: replace ss->id_lock with a rwlock") has now been seen to cause the unfair behavior we should have expected from converting a spinlock to an rwlock: softlockup in cgroup_mkdir(), whose get_new_cssid() is waiting for the wlock, while there are 19 tasks using the rlock in css_get_next() to get on with their memcg workload (in an artificial test, admittedly). Yet lib/idr.c was made suitable for RCU way back: revert that commit, restoring ss->id_lock to a spinlock. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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48fde701aff662559b38d9a609574068f22d00fe |
|
09-Jan-2012 |
Al Viro <viro@zeniv.linux.org.uk> |
switch open-coded instances of d_make_root() to new helper Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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3ce3230a0cff484e5130153f244d4fb8a56b3a8b |
|
08-Feb-2012 |
Frederic Weisbecker <fweisbec@gmail.com> |
cgroup: Walk task list under tasklist_lock in cgroup_enable_task_cg_list Walking through the tasklist in cgroup_enable_task_cg_list() inside an RCU read side critical section is not enough because: - RCU is not (yet) safe against while_each_thread() - If we use only RCU, a forking task that has passed cgroup_post_fork() without seeing use_task_css_set_links == 1 is not guaranteed to have its child immediately visible in the tasklist if we walk through it remotely with RCU. In this case it will be missing in its css_set's task list. Thus we need to traverse the list (unfortunately) under the tasklist_lock. It makes us safe against while_each_thread() and also make sure we see all forked task that have been added to the tasklist. As a secondary effect, reading and writing use_task_css_set_links are now well ordered against tasklist traversing and modification. The new layout is: CPU 0 CPU 1 use_task_css_set_links = 1 write_lock(tasklist_lock) read_lock(tasklist_lock) add task to tasklist do_each_thread() { write_unlock(tasklist_lock) add thread to css set links if (use_task_css_set_links) } while_each_thread() add thread to css set links read_unlock(tasklist_lock) If CPU 0 traverse the list after the task has been added to the tasklist then it is correctly added to the css set links. OTOH if CPU 0 traverse the tasklist before the new task had the opportunity to be added to the tasklist because it was too early in the fork process, then CPU 1 catches up and add the task to the css set links after it added the task to the tasklist. The right value of use_task_css_set_links is guaranteed to be visible from CPU 1 due to the LOCK/UNLOCK implicit barrier properties: the read_unlock on CPU 0 makes the write on use_task_css_set_links happening and the write_lock on CPU 1 make the read of use_task_css_set_links that comes afterward to return the correct value. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Mandeep Singh Baines <msb@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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9a4b430451bb6d8d6b7dcdfbee0e1330b7c475a6 |
|
08-Feb-2012 |
Frederic Weisbecker <fweisbec@gmail.com> |
cgroup: Remove wrong comment on cgroup_enable_task_cg_list() Remove the stale comment about RCU protection. Many callers (all of them?) of cgroup_enable_task_cg_list() don't seem to be in an RCU read side critical section. Besides, RCU is not helpful to protect against while_each_thread(). Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Mandeep Singh Baines <msb@chromium.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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761b3ef50e1c2649cffbfa67a4dcb2dcdb7982ed |
|
31-Jan-2012 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: remove cgroup_subsys argument from callbacks The argument is not used at all, and it's not necessary, because a specific callback handler of course knows which subsys it belongs to. Now only ->pupulate() takes this argument, because the handlers of this callback always call cgroup_add_file()/cgroup_add_files(). So we reduce a few lines of code, though the shrinking of object size is minimal. 16 files changed, 113 insertions(+), 162 deletions(-) text data bss dec hex filename 5486240 656987 7039960 13183187 c928d3 vmlinux.o.orig 5486170 656987 7039960 13183117 c9288d vmlinux.o Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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61d1d219c4c0761059236a46867bc49943c4d29d |
|
30-Jan-2012 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: remove extra calls to find_existing_css_set In cgroup_attach_proc, we indirectly call find_existing_css_set 3 times. It is an expensive call so we want to call it a minimum of times. This patch only calls it once and stores the result so that it can be used later on when we call cgroup_task_migrate. This required modifying cgroup_task_migrate to take the new css_set (which we obtained from find_css_set) as a parameter. The nice side effect of this is that cgroup_task_migrate is now identical for cgroup_attach_task and cgroup_attach_proc. It also now returns a void since it can never fail. Changes in V5: * https://lkml.org/lkml/2012/1/20/344 (Tejun Heo) * Remove css_set_refs Changes in V4: * https://lkml.org/lkml/2011/12/22/421 (Li Zefan) * Avoid GFP_KERNEL (sleep) in rcu_read_lock by getting css_set in a separate loop not under an rcu_read_lock Changes in V3: * https://lkml.org/lkml/2011/12/22/13 (Li Zefan) * Fixed earlier bug by creating a seperate patch to remove tasklist_lock Changes in V2: * https://lkml.org/lkml/2011/12/20/372 (Tejun Heo) * Move find_css_set call into loop which creates the flex array * Author * Kill css_set_refs and use group_size instead * Fix an off-by-one error in counting css_set refs * Add a retval check in out_list_teardown Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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fb5d2b4cfc24963d0e8a7df57de1ecffa10a04cf |
|
04-Jan-2012 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: replace tasklist_lock with rcu_read_lock We can replace the tasklist_lock in cgroup_attach_proc with an rcu_read_lock(). Changes in V4: * https://lkml.org/lkml/2011/12/23/284 (Frederic Weisbecker) * Minimize size of rcu_read_lock critical section * Add comment * https://lkml.org/lkml/2011/12/26/136 (Li Zefan) * Split into two patches Changes in V3: * https://lkml.org/lkml/2011/12/22/419 (Frederic Weisbecker) * Add an rcu_read_lock to protect against exit Changes in V2: * https://lkml.org/lkml/2011/12/22/86 (Tejun Heo) * Use a goto instead of returning -EAGAIN Suggested-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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b78949ebfb563c29808a9d0a772e3adb5561bc80 |
|
04-Jan-2012 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: simplify double-check locking in cgroup_attach_proc To keep the complexity of the double-check locking in one place, move the thread_group_leader check up into attach_task_by_pid(). This allows us to use a goto instead of returning -EAGAIN. While at it, convert a couple of returns to gotos and use rcu for the !pid case also in order to simplify the logic. Changes in V2: * https://lkml.org/lkml/2011/12/22/86 (Tejun Heo) * Use a goto instead of returning -EAGAIN Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
|
245282557c49754af3dbcc732316e814340d6bce |
|
20-Jan-2012 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: move struct cgroup_pidlist out from the header file It's internally used only. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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34c80b1d93e6e20ca9dea0baf583a5b5510d92d4 |
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09-Dec-2011 |
Al Viro <viro@zeniv.linux.org.uk> |
vfs: switch ->show_options() to struct dentry * Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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0d19ea866562e46989412a0676412fa0983c9ce7 |
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27-Dec-2011 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix to allow mounting a hierarchy by name If we mount a hierarchy with a specified name, the name is unique, and we can use it to mount the hierarchy without specifying its set of subsystem names. This feature is documented is Documentation/cgroups/cgroups.txt section 2.3 Here's an example: # mount -t cgroup -o cpuset,name=myhier xxx /cgroup1 # mount -t cgroup -o name=myhier xxx /cgroup2 But it was broken by commit 32a8cf235e2f192eb002755076994525cdbaa35a (cgroup: make the mount options parsing more accurate) This fixes the regression. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: stable@vger.kernel.org
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305f3c8b20ba1ca94829329acdbf22e689304dba |
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04-Jan-2012 |
Dan Carpenter <dan.carpenter@oracle.com> |
cgroup: move assignement out of condition in cgroup_attach_proc() Gcc complains about this: "kernel/cgroup.c:2179:4: warning: suggest parentheses around assignment used as truth value [-Wparentheses]" Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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a5e7ed3287e45f2eafbcf9e7e6fdc5a0191acf40 |
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26-Jul-2011 |
Al Viro <viro@zeniv.linux.org.uk> |
cgroup: propagate mode_t Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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18bb1db3e7607e4a997d50991a6f9fa5b0f8722c |
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26-Jul-2011 |
Al Viro <viro@zeniv.linux.org.uk> |
switch vfs_mkdir() and ->mkdir() to umode_t vfs_mkdir() gets int, but immediately drops everything that might not fit into umode_t and that's the only caller of ->mkdir()... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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7e3aa30ac8c904a706518b725c451bb486daaae9 |
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23-Dec-2011 |
Frederic Weisbecker <fweisbec@gmail.com> |
cgroup: Remove task_lock() from cgroup_post_fork() cgroup_post_fork() is protected between threadgroup_change_begin() and threadgroup_change_end() against concurrent changes of the child's css_set in cgroup_task_migrate(). Also the child can't exit and call cgroup_exit() at this stage, this means it's css_set can't be changed with init_css_set concurrently. For these reasons, we don't need to hold task_lock() on the child because it's css_set can only remain stable in this place. Let's remove the lock there. v2: Update comment to explain that we are safe against cgroup_exit() Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Containers <containers@lists.linux-foundation.org> Cc: Cgroups <cgroups@vger.kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org> Cc: Mandeep Singh Baines <msb@chromium.org>
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c6ca57500c23d57a4ccec9874b6a3c99c297e1b5 |
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27-Dec-2011 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroup: add sparse annotation to cgroup_iter_start() and cgroup_iter_end() Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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1c6c3fad81787e8cb4c85ddfd573b0d8442fe630 |
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27-Dec-2011 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroup: mark cgroup_rmdir_waitq and cgroup_attach_proc() as static Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
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892a2b90ba15cb7dbee40979f23fdb492913abf8 |
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22-Dec-2011 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: only need to check oldcgrp==newgrp once In cgroup_attach_proc it is now sufficient to only check that oldcgrp==newcgrp once. Now that we are using threadgroup_lock() during the migrations, oldcgrp will not change. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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b07ef7741122a83575499c11417e514877941e76 |
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22-Dec-2011 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: remove redundant get/put of task struct threadgroup_lock() guarantees that the target threadgroup will remain stable - no new task will be added, no new PF_EXITING will be set and exec won't happen. Changes in V2: * https://lkml.org/lkml/2011/12/20/369 (Tejun Heo) * Undo incorrect removal of get/put from attach_task_by_pid() * Author * Remove a comment which is made stale by this change Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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026085ef5ae07c3197f2baacc091ce067b86ed11 |
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22-Dec-2011 |
Mandeep Singh Baines <msb@chromium.org> |
cgroup: remove redundant get/put of old css_set from migrate We can now assume that the css_set reference held by the task will not go away for an exiting task. PF_EXITING state can be trusted throughout migration by checking it after locking threadgroup. Changes in V4: * https://lkml.org/lkml/2011/12/20/368 (Tejun Heo) * Fix typo in commit message * Undid the rename of css_set_check_fetched * https://lkml.org/lkml/2011/12/20/427 (Li Zefan) * Fix comment in cgroup_task_migrate() Changes in V3: * https://lkml.org/lkml/2011/12/20/255 (Frederic Weisbecker) * Fixed to put error in retval Changes in V2: * https://lkml.org/lkml/2011/12/19/289 (Tejun Heo) * Updated commit message -tj: removed stale patch description about dropped function rename. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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c84cdf75ccb2845f690579e838f13f7e744e3d23 |
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21-Dec-2011 |
Frederic Weisbecker <fweisbec@gmail.com> |
cgroup: Remove unnecessary task_lock before fetching css_set on migration When we fetch the css_set of the tasks on cgroup migration, we don't need anymore to synchronize against cgroup_exit() that could swap the old one with init_css_set. Now that we are using threadgroup_lock() during the migrations, we don't need to worry about it anymore. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Mandeep Singh Baines <msb@chromium.org> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Containers <containers@lists.linux-foundation.org> Cc: Cgroups <cgroups@vger.kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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7e381b0eb1e1a9805c37335562e8dc02e7d7848c |
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21-Dec-2011 |
Frederic Weisbecker <fweisbec@gmail.com> |
cgroup: Drop task_lock(parent) on cgroup_fork() We don't need to hold the parent task_lock() on the parent in cgroup_fork() because we are already synchronized against the two places that may change the parent css_set concurrently: - cgroup_exit(), but the parent obviously can't exit concurrently - cgroup migration: we are synchronized against threadgroup_lock() So we can safely remove the task_lock() there. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Containers <containers@lists.linux-foundation.org> Cc: Cgroups <cgroups@vger.kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org> Cc: Mandeep Singh Baines <msb@chromium.org>
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29e21368b9baf9c4b25060d65062da2dda926c70 |
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15-Dec-2011 |
Mandeep Singh Baines <msb@chromium.org> |
cgroups: remove redundant get/put of css_set from css_set_check_fetched() We already have a reference to all elements in newcg_list. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: Paul Menage <paul@paulmenage.org>
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e0197aae59e55c06db172bfbe1a1cdb8c0e1cab3 |
|
15-Dec-2011 |
Mandeep Singh Baines <msb@chromium.org> |
cgroups: fix a css_set not found bug in cgroup_attach_proc There is a BUG when migrating a PF_EXITING proc. Since css_set_prefetch() is not called for the PF_EXITING case, find_existing_css_set() will return NULL inside cgroup_task_migrate() causing a BUG. This bug is easy to reproduce. Create a zombie and echo its pid to cgroup.procs. $ cat zombie.c \#include <unistd.h> int main() { if (fork()) pause(); return 0; } $ We are hitting this bug pretty regularly on ChromeOS. This bug is already fixed by Tejun Heo's cgroup patchset which is targetted for the next merge window: https://lkml.org/lkml/2011/11/1/356 I've create a smaller patch here which just fixes this bug so that a fix can be merged into the current release and stable. Signed-off-by: Mandeep Singh Baines <msb@chromium.org> Downstream-Bug-Report: http://crosbug.com/23953 Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: containers@lists.linux-foundation.org Cc: cgroups@vger.kernel.org Cc: stable@kernel.org Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org> Cc: Olof Johansson <olofj@chromium.org>
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494c167cf76d02000adf740c215adc69a824ecc9 |
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13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task() These three methods are no longer used. Kill them. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com>
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2f7ee5691eecb67c8108b92001a85563ea336ac5 |
|
13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach() Currently, there's no way to pass multiple tasks to cgroup_subsys methods necessitating the need for separate per-process and per-task methods. This patch introduces cgroup_taskset which can be used to pass multiple tasks and their associated cgroups to cgroup_subsys methods. Three methods - can_attach(), cancel_attach() and attach() - are converted to use cgroup_taskset. This unifies passed parameters so that all methods have access to all information. Conversions in this patchset are identical and don't introduce any behavior change. -v2: documentation updated as per Paul Menage's suggestion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: James Morris <jmorris@namei.org>
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134d33737f9015761c3832f6b268fae6274aac7f |
|
13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: improve old cgroup handling in cgroup_attach_proc() cgroup_attach_proc() behaves differently from cgroup_attach_task() in the following aspects. * All hooks are invoked even if no task is actually being moved. * ->can_attach_task() is called for all tasks in the group whether the new cgrp is different from the current cgrp or not; however, ->attach_task() is skipped if new equals new. This makes the calls asymmetric. This patch improves old cgroup handling in cgroup_attach_proc() by looking up the current cgroup at the head, recording it in the flex array along with the task itself, and using it to remove the above two differences. This will also ease further changes. -v2: nr_todo renamed to nr_migrating_tasks as per Paul Menage's suggestion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Paul Menage <paul@paulmenage.org> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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cd3d095275374220921fcf0d4e0c16584b26ddbc |
|
13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: always lock threadgroup during migration Update cgroup to take advantage of the fack that threadgroup_lock() guarantees stable threadgroup. * Lock threadgroup even if the target is a single task. This guarantees that when the target tasks stay stable during migration regardless of the target type. * Remove PF_EXITING early exit optimization from attach_task_by_pid() and check it in cgroup_task_migrate() instead. The optimization was for rather cold path to begin with and PF_EXITING state can be trusted throughout migration by checking it after locking threadgroup. * Don't add PF_EXITING tasks to target task array in cgroup_attach_proc(). This ensures that task migration is performed only for live tasks. * Remove -ESRCH failure path from cgroup_task_migrate(). With the above changes, it's guaranteed to be called only for live tasks. After the changes, only live tasks are migrated and they're guaranteed to stay alive until migration is complete. This removes problems caused by exec and exit racing against cgroup migration including symmetry among cgroup attach methods and different cgroup methods racing each other. v2: Oleg pointed out that one more PF_EXITING check can be removed from cgroup_attach_proc(). Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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257058ae2b971646b96ab3a15605ac69186e562a |
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13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem Make the following renames to prepare for extension of threadgroup locking. * s/signal->threadgroup_fork_lock/signal->group_rwsem/ * s/threadgroup_fork_read_lock()/threadgroup_change_begin()/ * s/threadgroup_fork_read_unlock()/threadgroup_change_end()/ * s/threadgroup_fork_write_lock()/threadgroup_lock()/ * s/threadgroup_fork_write_unlock()/threadgroup_unlock()/ This patch doesn't cause any behavior change. -v2: Rename threadgroup_change_done() to threadgroup_change_end() per KAMEZAWA's suggestion. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Menage <paul@paulmenage.org>
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e25e2cbb4c6679bed5f52fb0f2cc381688297901 |
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13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: add cgroup_root_mutex cgroup wants to make threadgroup stable while modifying cgroup hierarchies which will introduce locking dependency on cred_guard_mutex from cgroup_mutex. This unfortunately completes circular dependency. A. cgroup_mutex -> cred_guard_mutex -> s_type->i_mutex_key -> namespace_sem B. namespace_sem -> cgroup_mutex B is from cgroup_show_options() and this patch breaks it by introducing another mutex cgroup_root_mutex which nests inside cgroup_mutex and protects cgroupfs_root. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com>
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c1e2ee2dc436574880758b3836fc96935b774c32 |
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02-Nov-2011 |
Andrew Bresticker <abrestic@google.com> |
memcg: replace ss->id_lock with a rwlock While back-porting Johannes Weiner's patch "mm: memcg-aware global reclaim" for an internal effort, we noticed a significant performance regression during page-reclaim heavy workloads due to high contention of the ss->id_lock. This lock protects idr map, and serializes calls to idr_get_next() in css_get_next() (which is used during the memcg hierarchy walk). Since idr_get_next() is just doing a look up, we need only serialize it with respect to idr_remove()/idr_get_new(). By making the ss->id_lock a rwlock, contention is greatly reduced and performance improves. Tested: cat a 256m file from a ramdisk in a 128m container 50 times on each core (one file + container per core) in parallel on a NUMA machine. Result is the time for the test to complete in 1 of the containers. Both kernels included Johannes' memcg-aware global reclaim patches. Before rwlock patch: 1710.778s After rwlock patch: 152.227s Signed-off-by: Andrew Bresticker <abrestic@google.com> Cc: Paul Menage <menage@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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77ceab8ea590d7dc6c8f055ce43dfebd74428107 |
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02-Nov-2011 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: don't attach task to subsystem if migration failed If a task has exited to the point it has called cgroup_exit() already, then we can't migrate it to another cgroup anymore. This can happen when we are attaching a task to a new cgroup between the call to ->can_attach_task() on subsystems and the migration that is eventually tried in cgroup_task_migrate(). In this case cgroup_task_migrate() returns -ESRCH and we don't want to attach the task to the subsystems because the attachment to the new cgroup itself failed. Fix this by only calling ->attach_task() on the subsystems if the cgroup migration succeeded. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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33ef6b6984403a688189317ef46bb3caab3b70e0 |
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02-Nov-2011 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: more safe tasklist locking in cgroup_attach_proc Fix unstable tasklist locking in cgroup_attach_proc. According to this thread - https://lkml.org/lkml/2011/7/27/243 - RCU is not sufficient to guarantee the tasklist is stable w.r.t. de_thread and exit. Taking tasklist_lock for reading, instead of rcu_read_lock, ensures proper exclusion. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Paul Menage <paul@paulmenage.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cdcc136ffd264849a943acb42c36ffe9b458f811 |
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25-Jul-2009 |
Thomas Gleixner <tglx@linutronix.de> |
locking, sched, cgroups: Annotate release_list_lock as raw The release_list_lock can be taken in atomic context and therefore cannot be preempted on -rt - annotate it. In mainline this change documents the low level nature of the lock - otherwise there's no functional difference. Lockdep and Sparse checking will work as usual. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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60063497a95e716c9a689af3be2687d261f115b4 |
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27-Jul-2011 |
Arun Sharma <asharma@fb.com> |
atomic: use <linux/atomic.h> This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3bfa784a6539f91a27d7ffdd408efdb638e3bebd |
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19-Jun-2011 |
Al Viro <viro@zeniv.linux.org.uk> |
kill file_permission() completely convert the last remaining caller to inode_permission() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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d8bf4ca9ca9576548628344c9725edd3786e90b1 |
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08-Jul-2011 |
Michal Hocko <mhocko@suse.cz> |
rcu: treewide: Do not use rcu_read_lock_held when calling rcu_dereference_check Since ca5ecddf (rcu: define __rcu address space modifier for sparse) rcu_dereference_check use rcu_read_lock_held as a part of condition automatically so callers do not have to do that as well. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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2ce9738bac1b386f46e8478fd2c263460e7c2b09 |
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02-Jun-2011 |
eparis@redhat <eparis@redhat> |
cgroupfs: use init_cred when populating new cgroupfs mount We recently found that in some configurations SELinux was blocking the ability for cgroupfs to be mounted. The reason for this is because cgroupfs creates files and directories during the get_sb() call and also uses lookup_one_len() during that same get_sb() call. This is a problem since the security subsystem cannot initialize the superblock and the inodes in that filesystem until after the get_sb() call returns. Thus we leave the inodes in an unitialized state during get_sb(). For the vast majority of filesystems this is not an issue, but since cgroupfs uses lookup_on_len() it does search permission checks on the directories in the path it walks. Since the inode security state is not set up SELinux does these checks as if the inodes were 'unlabeled.' Many 'normal' userspace process do not have permission to interact with unlabeled inodes. The solution presented here is to do the permission checks of path walk and inode creation as the kernel rather than as the task that called mount. Since the kernel has permission to read/write/create unlabeled inodes the get_sb() call will complete successfully and the SELinux code will be able to initialize the superblock and those inodes created during the get_sb() call. This appears to be the same solution used by other filesystems such as devtmpfs to solve the same issue and should thus have no negative impact on other LSMs which currently work. Signed-off-by: Eric Paris <eparis@redhat.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: James Morris <jmorris@namei.org>
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a77aea92010acf54ad785047234418d5d68772e2 |
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27-May-2011 |
Daniel Lezcano <daniel.lezcano@free.fr> |
cgroup: remove the ns_cgroup The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and leads to some problems: * cgroup creation is out-of-control * cgroup name can conflict when pids are looping * it is not possible to have a single process handling a lot of namespaces without falling in a exponential creation time * we may want to create a namespace without creating a cgroup The ns_cgroup was replaced by a compatibility flag 'clone_children', where a newly created cgroup will copy the parent cgroup values. The userspace has to manually create a cgroup and add a task to the 'tasks' file. This patch removes the ns_cgroup as suggested in the following thread: https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html The 'cgroup_clone' function is removed because it is no longer used. This is a userspace-visible change. Commit 45531757b45c ("cgroup: notify ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a printk warning users that the feature is planned for removal. Since that time we have heard from XXX users who were affected by this. Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d846687d7f84e45f23ecf3846dbb43312a1206dd |
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27-May-2011 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: use flex_array in attach_proc Convert cgroup_attach_proc to use flex_array. The cgroup_attach_proc implementation requires a pre-allocated array to store task pointers to atomically move a thread-group, but asking for a monolithic array with kmalloc() may be unreliable for very large groups. Using flex_array provides the same functionality with less risk of failure. This is a post-patch for cgroup-procs-write.patch. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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74a1166dfe1135dcc168d35fa5261aa7e087011b |
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27-May-2011 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: make procs file writable Make procs file writable to move all threads by tgid at once. Add functionality that enables users to move all threads in a threadgroup at once to a cgroup by writing the tgid to the 'cgroup.procs' file. This current implementation makes use of a per-threadgroup rwsem that's taken for reading in the fork() path to prevent newly forking threads within the threadgroup from "escaping" while the move is in progress. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f780bdb7c1c73009cb57adcf99ef50027d80bf3c |
|
27-May-2011 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: add per-thread subsystem callbacks Add cgroup subsystem callbacks for per-thread attachment in atomic contexts Add can_attach_task(), pre_attach(), and attach_task() as new callbacks for cgroups's subsystem interface. Unlike can_attach and attach, these are for per-thread operations, to be called potentially many times when attaching an entire threadgroup. Also, the old "bool threadgroup" interface is removed, as replaced by this. All subsystems are modified for the new interface - of note is cpuset, which requires from/to nodemasks for attach to be globally scoped (though per-cpuset would work too) to persist from its pre_attach to attach_task and attach. This is a pre-patch for cgroup-procs-writable.patch. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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025cea99db3fb110ebc8ede5ff647833fab9574f |
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15-Mar-2011 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroup,rcu: convert call_rcu(__free_css_id_cb) to kfree_rcu() The rcu callback __free_css_id_cb() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(__free_css_id_cb). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
|
f2da1c40dc003939f616f27a103b2592f1424b07 |
|
15-Mar-2011 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroup,rcu: convert call_rcu(free_cgroup_rcu) to kfree_rcu() The rcu callback free_cgroup_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_cgroup_rcu). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
|
30088ad815802f850f26114920ccf9effd4bc520 |
|
15-Mar-2011 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroup,rcu: convert call_rcu(free_css_set_rcu) to kfree_rcu() The rcu callback free_css_set_rcu() just calls a kfree(), so we use kfree_rcu() instead of the call_rcu(free_css_set_rcu). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
|
25985edcedea6396277003854657b5f3cb31a628 |
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31-Mar-2011 |
Lucas De Marchi <lucas.demarchi@profusion.mobi> |
Fix common misspellings Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
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8d2587970b8bdf7c8d9208e3f4bb93182aef1a0f |
|
23-Mar-2011 |
Phil Carmody <ext-phil.2.carmody@nokia.com> |
cgroups: if you list_empty() a head then don't list_del() it list_del() leaves poison in the prev and next pointers. The next list_empty() will compare those poisons, and say the list isn't empty. Any list operations that assume the node is on a list because of such a check will be fooled into dereferencing poison. One needs to INIT the node after the del, and fortunately there's already a wrapper for that - list_del_init(). Some of the dels are followed by deallocations, so can be ignored, and one can be merged with an add to make a move. Apart from that, I erred on the side of caution in making nodes list_empty()-queriable. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e5d1367f17ba6a6fed5fd8b74e4d5720923e0c25 |
|
14-Feb-2011 |
Stephane Eranian <eranian@google.com> |
perf: Add cgroup support This kernel patch adds the ability to filter monitoring based on container groups (cgroups). This is for use in per-cpu mode only. The cgroup to monitor is passed as a file descriptor in the pid argument to the syscall. The file descriptor must be opened to the cgroup name in the cgroup filesystem. For instance, if the cgroup name is foo and cgroupfs is mounted in /cgroup, then the file descriptor is opened to /cgroup/foo. Cgroup mode is activated by passing PERF_FLAG_PID_CGROUP in the flags argument to the syscall. For instance to measure in cgroup foo on CPU1 assuming cgroupfs is mounted under /cgroup: struct perf_event_attr attr; int cgroup_fd, fd; cgroup_fd = open("/cgroup/foo", O_RDONLY); fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP); close(cgroup_fd); Signed-off-by: Stephane Eranian <eranian@google.com> [ added perf_cgroup_{exit,attach} ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4d590250.114ddf0a.689e.4482@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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d41d5a01631af821d3a3447e6613a316f5ee6c25 |
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07-Feb-2011 |
Peter Zijlstra <a.p.zijlstra@chello.nl> |
cgroup: Fix cgroup_subsys::exit callback Make the ::exit method act like ::attach, it is after all very nearly the same thing. The bug had no effect on correctness - fixing it is an optimization for the scheduler. Also, later perf-cgroups patches rely on it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Menage <menage@google.com> LKML-Reference: <1297160655.13327.92.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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c72a04e34735ec3f19f4788b7f95017310b5e1eb |
|
14-Jan-2011 |
Al Viro <viro@ZenIV.linux.org.uk> |
cgroup_fs: fix cgroup use of simple_lookup() cgroup can't use simple_lookup(), since that'd override its desired ->d_op. Tested-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3ec762ad8be364c2fadfe0d6b2cc6d4d3b5e1b54 |
|
14-Jan-2011 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: Fix a lockdep warning at cgroup removal Commit 2fd6b7f5 ("fs: dcache scale subdirs") forgot to annotate a dentry lock, which caused a lockdep warning. Reported-by: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
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0df6a63f8735a7c8a877878bc215d4312e41ef81 |
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21-Dec-2010 |
Al Viro <viro@zeniv.linux.org.uk> |
switch cgroup switching it to s_d_op allows to kill the cgroup_lookup() kludge. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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fb045adb99d9b7c562dc7fef834857f78249daa1 |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: dcache reduce branches in lookup path Reduce some branches and memory accesses in dcache lookup by adding dentry flags to indicate common d_ops are set, rather than having to check them. This saves a pointer memory access (dentry->d_op) in common path lookup situations, and saves another pointer load and branch in cases where we have d_op but not the particular operation. Patched with: git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i Signed-off-by: Nick Piggin <npiggin@kernel.dk>
|
dc0474be3e27463d4d4a2793f82366eed906f223 |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: dcache rationalise dget variants dget_locked was a shortcut to avoid the lazy lru manipulation when we already held dcache_lock (lru manipulation was relatively cheap at that point). However, how that the lru lock is an innermost one, we never hold it at any caller, so the lock cost can now be avoided. We already have well working lazy dcache LRU, so it should be fine to defer LRU manipulations to scan time. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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b5c84bf6f6fa3a7dfdcb556023a62953574b60ee |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: dcache remove dcache_lock dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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2fd6b7f50797f2e993eea59e0a0b8c6399c811dc |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: dcache scale subdirs Protect d_subdirs and d_child with d_lock, except in filesystems that aren't using dcache_lock for these anyway (eg. using i_mutex). Note: if we change the locking rule in future so that ->d_child protection is provided only with ->d_parent->d_lock, it may allow us to reduce some locking. But it would be an exception to an otherwise regular locking scheme, so we'd have to see some good results. Probably not worthwhile. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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b7ab39f631f505edc2bbdb86620d5493f995c9da |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: dcache scale dentry refcount Make d_count non-atomic and protect it with d_lock. This allows us to ensure a 0 refcount dentry remains 0 without dcache_lock. It is also fairly natural when we start protecting many other dentry members with d_lock. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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fe15ce446beb3a33583af81ffe6c9d01a75314ed |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
fs: change d_delete semantics Change d_delete from a dentry deletion notification to a dentry caching advise, more like ->drop_inode. Require it to be constant and idempotent, and not take d_lock. This is how all existing filesystems use the callback anyway. This makes fine grained dentry locking of dput and dentry lru scanning much simpler. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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5adcee1d8d32d7f305f6f5aaefdbf8f35adca177 |
|
07-Jan-2011 |
Nick Piggin <npiggin@kernel.dk> |
cgroup fs: avoid switching ->d_op on live dentry Switching d_op on a live dentry is racy in general, so avoid it. In this case it is a negative dentry, which is safer, but there are still concurrent ops which may be called on d_op in that case (eg. d_revalidate). So in general a filesystem may not do this. Fix cgroupfs so as not to do this. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
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f7e835710ab5f6e43933c983f38f2d2e262b718c |
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26-Jul-2010 |
Al Viro <viro@zeniv.linux.org.uk> |
convert cgroup and cpuset Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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f4a2589feaef0a9b737a3e582b37ee96695bb25f |
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28-Oct-2010 |
Evgeny Kuznetsov <ext-eugeny.kuznetsov@nokia.com> |
cgroups: add check for strcpy destination string overflow Function "strcpy" is used without check for maximum allowed source string length and could cause destination string overflow. Check for string length is added before using "strcpy". Function now is return error if source string length is more than a maximum. akpm: presently considered NotABug, but add the check for general future-safeness and robustness. Signed-off-by: Evgeny Kuznetsov <EXT-Eugeny.Kuznetsov@nokia.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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32a8cf235e2f192eb002755076994525cdbaa35a |
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28-Oct-2010 |
Daniel Lezcano <daniel.lezcano@free.fr> |
cgroup: make the mount options parsing more accurate Current behavior: ================= (1) When we mount a cgroup, we can specify the 'all' option which means to enable all the cgroup subsystems. This is the default option when no option is specified. (2) If we want to mount a cgroup with a subset of the supported cgroup subsystems, we have to specify a subsystems name list for the mount option. (3) If we specify another option like 'noprefix' or 'release_agent', the actual code wants the 'all' or a subsystem name option specified also. Not critical but a bit not friendly as we should assume (1) in this case. (4) Logically, the 'all' option is mutually exclusive with a subsystem name, but this is not detected. In other words: succeed : mount -t cgroup -o all,freezer cgroup /cgroup => is it 'all' or 'freezer' ? fails : mount -t cgroup -o noprefix cgroup /cgroup => succeed if we do '-o noprefix,all' The following patches consolidate a bit the mount options check. New behavior: ============= (1) untouched (2) untouched (3) the 'all' option will be by default when specifying other than a subsystem name option (4) raises an error In other words: fails : mount -t cgroup -o all,freezer cgroup /cgroup succeed : mount -t cgroup -o noprefix cgroup /cgroup For the sake of lisibility, the if ... then ... else ... if ... indentation when parsing the options has been changed to: if ... then ... continue fi Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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97978e6d1f2da0073416870410459694fbdbfd9b |
|
28-Oct-2010 |
Daniel Lezcano <daniel.lezcano@free.fr> |
cgroup: add clone_children control file The ns_cgroup is a control group interacting with the namespaces. When a new namespace is created, a corresponding cgroup is automatically created too. The cgroup name is the pid of the process who did 'unshare' or the child of 'clone'. This cgroup is tied with the namespace because it prevents a process to escape the control group and use the post_clone callback, so the child cgroup inherits the values of the parent cgroup. Unfortunately, the more we use this cgroup and the more we are facing problems with it: (1) when a process unshares, the cgroup name may conflict with a previous cgroup with the same pid, so unshare or clone return -EEXIST (2) the cgroup creation is out of control because there may have an application creating several namespaces where the system will automatically create several cgroups in his back and let them on the cgroupfs (eg. a vrf based on the network namespace). (3) the mix of (1) and (2) force an administrator to regularly check and clean these cgroups. This patchset removes the ns_cgroup by adding a new flag to the cgroup and the cgroupfs mount option. It enables the copy of the parent cgroup when a child cgroup is created. We can then safely remove the ns_cgroup as this flag brings a compatibility. We have now to manually create and add the task to a cgroup, which is consistent with the cgroup framework. This patch: Sent as an answer to a previous thread around the ns_cgroup. https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html It adds a control file 'clone_children' for a cgroup. This control file is a boolean specifying if the child cgroup should be a clone of the parent cgroup or not. The default value is 'false'. This flag makes the child cgroup to call the post_clone callback of all the subsystem, if it is available. At present, the cpuset is the only one which had implemented the post_clone callback. The option can be set at mount time by specifying the 'clone_children' mount option. Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Acked-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Jamal Hadi Salim <hadi@cyberus.ca> Cc: Matt Helsley <matthltc@us.ibm.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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85fe4025c616a7c0ed07bc2fc8c5371b07f3888c |
|
23-Oct-2010 |
Christoph Hellwig <hch@lst.de> |
fs: do not assign default i_ino in new_inode Instead of always assigning an increasing inode number in new_inode move the call to assign it into those callers that actually need it. For now callers that need it is estimated conservatively, that is the call is added to all filesystems that do not assign an i_ino by themselves. For a few more filesystems we can avoid assigning any inode number given that they aren't user visible, and for others it could be done lazily when an inode number is actually needed, but that's left for later patches. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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38d018dba3f725b969f196550d92a6ec1c092428 |
|
24-Feb-2010 |
Jan Blunck <jblunck@infradead.org> |
BKL: Remove BKL from cgroup The BKL is only used in remount_fs and get_sb that are both protected by the superblocks s_umount rw_semaphore. Therefore it is safe to remove the BKL entirely. Signed-off-by: Jan Blunck <jblunck@infradead.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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db71922217a214e5c9268448e537b54fc1f301ea |
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15-Aug-2010 |
Jan Blunck <jblunck@infradead.org> |
BKL: Explicitly add BKL around get_sb/fill_super This patch is a preparation necessary to remove the BKL from do_new_mount(). It explicitly adds calls to lock_kernel()/unlock_kernel() around get_sb/fill_super operations for filesystems that still uses the BKL. I've read through all the code formerly covered by the BKL inside do_kern_mount() and have satisfied myself that it doesn't need the BKL any more. do_kern_mount() is already called without the BKL when mounting the rootfs and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called from various places without BKL: simple_pin_fs(), nfs_do_clone_mount() through nfs_follow_mountpoint(), afs_mntpt_do_automount() through afs_mntpt_follow_link(). Both later functions are actually the filesystems follow_link inode operation. vfs_kern_mount() is calling the specified get_sb function and lets the filesystem do its job by calling the given fill_super function. Therefore I think it is safe to push down the BKL from the VFS to the low-level filesystems get_sb/fill_super operation. [arnd: do not add the BKL to those file systems that already don't use it elsewhere] Signed-off-by: Jan Blunck <jblunck@infradead.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Christoph Hellwig <hch@infradead.org>
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31583bb0cf6cc40f2a468a4d2f3b9cbefd24f891 |
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10-Sep-2010 |
Michael S. Tsirkin <mst@redhat.com> |
cgroups: fix API thinko Add cgroup_attach_task_all() The existing cgroup_attach_task_current_cg() API is called by a thread to attach another thread to all of its cgroups; this is unsuitable for cases where a privileged task wants to attach itself to the cgroups of a less privileged one, since the call must be made from the context of the target task. This patch adds a more generic cgroup_attach_task_all() API that allows both the source task and to-be-moved task to be specified. cgroup_attach_task_current_cg() becomes a specialization of the more generic new function. [menage@google.com: rewrote changelog] [akpm@linux-foundation.org: address reviewer comments] Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Tested-by: Alex Williamson <alex.williamson@redhat.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ben Blum <bblum@google.com> Cc: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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73457f0f836956747e0394320be2163c050e96ef |
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06-Aug-2010 |
Michael S. Tsirkin <mst@redhat.com> |
cgroups: fix API thinko cgroup_attach_task_current_cg API that have upstream is backwards: we really need an API to attach to the cgroups from another process A to the current one. In our case (vhost), a priveledged user wants to attach it's task to cgroups from a less priveledged one, the API makes us run it in the other task's context, and this fails. So let's make the API generic and just pass in 'from' and 'to' tasks. Add an inline wrapper for cgroup_attach_task_current_cg to avoid breaking bisect. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com>
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2c392b8c3450ceb69ba1b93cb0cddb3998fb8cdc |
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24-Feb-2010 |
Arnd Bergmann <arnd@arndb.de> |
cgroups: __rcu annotations Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
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e400c28524af2d344b1663b27bf28984fa959a0e |
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11-Aug-2010 |
Dan Carpenter <error27@gmail.com> |
cgroups: save space for the terminator The original code didn't leave enough space for a NULL terminator. These strings are copied with strcpy() into fixed length buffers in cgroup_root_from_opts(). Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: Serge E. Hallyn <serge@hallyn.com> Reviewd-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Ben Blum <bblum@andrew.cmu.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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676db4af043014e852f67ba0349dae0071bd11f3 |
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05-Aug-2010 |
Greg KH <gregkh@suse.de> |
cgroupfs: create /sys/fs/cgroup to mount cgroupfs on We really shouldn't be asking userspace to create new root filesystems. So follow along with all of the other in-kernel filesystems, and provide a mount point in sysfs. For cgroupfs, this should be in /sys/fs/cgroup/ This change provides that mount point when the cgroup filesystem is registered in the kernel. Acked-by: Paul Menage <menage@google.com> Acked-by: Dhaval Giani <dhaval.giani@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Lennart Poettering <lennart@poettering.net> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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d7926ee38f5c6e0bbebe712304f99a4c67e40f84 |
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30-May-2010 |
Sridhar Samudrala <samudrala.sridhar@gmail.com> |
cgroups: Add an API to attach a task to current task's cgroup Add a new kernel API to attach a task to current task's cgroup in all the active hierarchies. Signed-off-by: Sridhar Samudrala <sri@us.ibm.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Reviewed-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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94b3dd0f7bb393d93e84a173b1df9b8b64c83ac4 |
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04-Jun-2010 |
Greg Thelen <gthelen@google.com> |
cgroups: alloc_css_id() increments hierarchy depth Child groups should have a greater depth than their parents. Prior to this change, the parent would incorrectly report zero memory usage for child cgroups when use_hierarchy is enabled. test script: mount -t cgroup none /cgroups -o memory cd /cgroups mkdir cg1 echo 1 > cg1/memory.use_hierarchy mkdir cg1/cg11 echo $$ > cg1/cg11/tasks dd if=/dev/zero of=/tmp/foo bs=1M count=1 echo echo CHILD grep cache cg1/cg11/memory.stat echo echo PARENT grep cache cg1/memory.stat echo $$ > tasks rmdir cg1/cg11 cg1 cd / umount /cgroups Using fae9c79, a recent patch that changed alloc_css_id() depth computation, the parent incorrectly reports zero usage: root@ubuntu:~# ./test 1+0 records in 1+0 records out 1048576 bytes (1.0 MB) copied, 0.0151844 s, 69.1 MB/s CHILD cache 1048576 total_cache 1048576 PARENT cache 0 total_cache 0 With this patch, the parent correctly includes child usage: root@ubuntu:~# ./test 1+0 records in 1+0 records out 1048576 bytes (1.0 MB) copied, 0.0136827 s, 76.6 MB/s CHILD cache 1052672 total_cache 1052672 PARENT cache 0 total_cache 1052672 Signed-off-by: Greg Thelen <gthelen@google.com> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: <stable@kernel.org> [2.6.34.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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907860ed381a31b0102f362df67c1c5cae6ef050 |
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26-May-2010 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroups: make cftype.unregister_event() void-returning Since we are unable to handle an error returned by cftype.unregister_event() properly, let's make the callback void-returning. mem_cgroup_unregister_event() has been rewritten to be a "never fail" function. On mem_cgroup_usage_register_event() we save old buffer for thresholds array and reuse it in mem_cgroup_usage_unregister_event() to avoid allocation. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Phil Carmody <ext-phil.2.carmody@nokia.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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747388d78a0ae768fd82b55c4ed38aa646a72364 |
|
11-May-2010 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: fix css_is_ancestor() RCU locking Some callers (in memcontrol.c) calls css_is_ancestor() without rcu_read_lock. Because css_is_ancestor() has to access RCU protected data, it should be under rcu_read_lock(). This makes css_is_ancestor() itself does safe access to RCU protected area. (At least, "root" can have refcnt==0 if it's not an ancestor of "child". So, we need rcu_read_lock().) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
7f0f15464185a92f9d8791ad231bcd7bf6df54e4 |
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11-May-2010 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: fix css_id() RCU locking for real Commit ad4ba375373937817404fd92239ef4cadbded23b ("memcg: css_id() must be called under rcu_read_lock()") modifies memcontol.c for fixing RCU check message. But Andrew Morton pointed out that the fix doesn't seems sane and it was just for hidining lockdep messages. This is a patch for do proper things. Checking again, all places, accessing without rcu_read_lock, that commit fixies was intentional.... all callers of css_id() has reference count on it. So, it's not necessary to be under rcu_read_lock(). Considering again, we can use rcu_dereference_check for css_id(). We know css->id is valid if css->refcnt > 0. (css->id never changes and freed after css->refcnt going to be 0.) This patch makes use of rcu_dereference_check() in css_id/depth and remove unnecessary rcu-read-lock added by the commit. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a93d2f1744206827ccf416e2cdc5018aa503314e |
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07-May-2010 |
Changli Gao <xiaosuo@gmail.com> |
sched, wait: Use wrapper functions epoll should not touch flags in wait_queue_t. This patch introduces a new function __add_wait_queue_exclusive(), for the users, who use wait queue as a LIFO queue. __add_wait_queue_tail_exclusive() is introduced too instead of add_wait_queue_exclusive_locked(). remove_wait_queue_locked() is removed, as it is a duplicate of __remove_wait_queue(), disliked by users, and with less users. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: <containers@lists.linux-foundation.org> LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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fae9c791703606636c1220e47f6690660042ce7f |
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22-Apr-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: Fix an RCU warning in alloc_css_id() With CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o memory xxx /mnt # mkdir /mnt/0 ... kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection! ... This is a false-positive. It's safe to directly access parent_css->id. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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9a9686b634acc5cb6b7c601c171ae64af0318a24 |
|
22-Apr-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: Fix an RCU warning in cgroup_path() with CONFIG_PROVE_RCU=y, a warning can be triggered: # mount -t cgroup -o debug xxx /mnt # cat /proc/$$/cgroup ... kernel/cgroup.c:1649 invoked rcu_dereference_check() without protection! ... This is a false-positive, because cgroup_path() can be called with either rcu_read_lock() held or cgroup_mutex held. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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9d34706f42f9b8c15185423d9af98d37ba21d011 |
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23-Mar-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: remove duplicate include commit e6a1105b ("cgroups: subsystem module loading interface") and commit c50cc752 ("sched, cgroups: Fix module export") result in duplicate including of module.h Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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88393161210493e317ae391696ee8ef463cb3c23 |
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16-Mar-2010 |
Thomas Weber <swirl@gmx.li> |
Fix typos in comments [Ss]ytem => [Ss]ystem udpate => update paramters => parameters orginal => original Signed-off-by: Thomas Weber <swirl@gmx.li> Acked-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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a0a4db548edcce067c1201ef25cf2bc29f32dca4 |
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11-Mar-2010 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroups: remove events before destroying subsystem state objects Events should be removed after rmdir of cgroup directory, but before destroying subsystem state objects. Let's take reference to cgroup directory dentry to do that. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4ab78683c17d739c2a2077141dcf81a02b7fb57e |
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11-Mar-2010 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroups: fix race between userspace and kernelspace Notify userspace about cgroup removing only after rmdir of cgroup directory to avoid race between userspace and kernelspace. eventfd are used to notify about two types of event: - control file-specific, like crossing memory threshold; - cgroup removing. To understand what really happen, userspace can check if the cgroup still exists. To avoid race beetween userspace and kernelspace we have to notify userspace about cgroup removing only after rmdir of cgroup directory. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0dea116876eefc9c7ca9c5d74fe665481e499fa3 |
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11-Mar-2010 |
Kirill A. Shutemov <kirill@shutemov.name> |
cgroup: implement eventfd-based generic API for notifications This patchset introduces eventfd-based API for notifications in cgroups and implements memory notifications on top of it. It uses statistics in memory controler to track memory usage. Output of time(1) on building kernel on tmpfs: Root cgroup before changes: make -j2 506.37 user 60.93s system 193% cpu 4:52.77 total Non-root cgroup before changes: make -j2 507.14 user 62.66s system 193% cpu 4:54.74 total Root cgroup after changes (0 thresholds): make -j2 507.13 user 62.20s system 193% cpu 4:53.55 total Non-root cgroup after changes (0 thresholds): make -j2 507.70 user 64.20s system 193% cpu 4:55.70 total Root cgroup after changes (1 thresholds, never crossed): make -j2 506.97 user 62.20s system 193% cpu 4:53.90 total Non-root cgroup after changes (1 thresholds, never crossed): make -j2 507.55 user 64.08s system 193% cpu 4:55.63 total This patch: Introduce the write-only file "cgroup.event_control" in every cgroup. To register new notification handler you need: - create an eventfd; - open a control file to be monitored. Callbacks register_event() and unregister_event() must be defined for the control file; - write "<event_fd> <control_fd> <args>" to cgroup.event_control. Interpretation of args is defined by control file implementation; eventfd will be woken up by control file implementation or when the cgroup is removed. To unregister notification handler just close eventfd. If you need notification functionality for a control file you have to implement callbacks register_event() and unregister_event() in the struct cftype. [kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix] Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Dan Malek <dan@embeddedalley.com> Cc: Vladislav Buzov <vbuzov@embeddedalley.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Alexander Shishkin <virtuoso@slind.org> Cc: Davide Libenzi <davidel@xmailserver.org> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b70cc5fdb445a6929a01e9c406593265b136c99d |
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11-Mar-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: clean up cgroup_pidlist_find() a bit Don't call get_pid_ns() before we locate/alloc the ns. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Serge Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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67523c48aa74d5637848edeccf285af1c60bf14a |
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11-Mar-2010 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: blkio subsystem as module Modify the Block I/O cgroup subsystem to be able to be built as a module. As the CFQ disk scheduler optionally depends on blk-cgroup, config options in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are enhanced to support the new module dependency. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cf5d5941fda647fe3d2f2d00cf9e0245236a5f08 |
|
11-Mar-2010 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: subsystem module unloading Provides support for unloading modular subsystems. This patch adds a new function cgroup_unload_subsys which is to be used for removing a loaded subsystem during module deletion. Reference counting of the subsystems' modules is moved from once (at load time) to once per attached hierarchy (in parse_cgroupfs_options and rebind_subsystems) (i.e., 0 or 1). Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e6a1105ba08b265023dd71a4174fb4a29ebc7083 |
|
11-Mar-2010 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: subsystem module loading interface Add interface between cgroups subsystem management and module loading This patch implements rudimentary module-loading support for cgroups - namely, a cgroup_load_subsys (similar to cgroup_init_subsys) for use as a module initcall, and a struct module pointer in struct cgroup_subsys. Several functions that might be wanted by modules have had EXPORT_SYMBOL added to them, but it's unclear exactly which functions want it and which won't. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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aae8aab40367036931608fdaf9e2dc568b516f19 |
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11-Mar-2010 |
Ben Blum <bblum@andrew.cmu.edu> |
cgroups: revamp subsys array This patch series provides the ability for cgroup subsystems to be compiled as modules both within and outside the kernel tree. This is mainly useful for classifiers and subsystems that hook into components that are already modules. cls_cgroup and blkio-cgroup serve as the example use cases for this feature. It provides an interface cgroup_load_subsys() and cgroup_unload_subsys() which modular subsystems can use to register and depart during runtime. The net_cls classifier subsystem serves as the example for a subsystem which can be converted into a module using these changes. Patch #1 sets up the subsys[] array so its contents can be dynamic as modules appear and (eventually) disappear. Iterations over the array are modified to handle when subsystems are absent, and the dynamic section of the array is protected by cgroup_mutex. Patch #2 implements an interface for modules to load subsystems, called cgroup_load_subsys, similar to cgroup_init_subsys, and adds a module pointer in struct cgroup_subsys. Patch #3 adds a mechanism for unloading modular subsystems, which includes a more advanced rework of the rudimentary reference counting introduced in patch 2. Patch #4 modifies the net_cls subsystem, which already had some module declarations, to be configurable as a module, which also serves as a simple proof-of-concept. Part of implementing patches 2 and 4 involved updating css pointers in each css_set when the module appears or leaves. In doing this, it was discovered that css_sets always remain linked to the dummy cgroup, regardless of whether or not any subsystems are actually bound to it (i.e., not mounted on an actual hierarchy). The subsystem loading and unloading code therefore should keep in mind the special cases where the added subsystem is the only one in the dummy cgroup (and therefore all css_sets need to be linked back into it) and where the removed subsys was the only one in the dummy cgroup (and therefore all css_sets should be unlinked from it) - however, as all css_sets always stay attached to the dummy cgroup anyway, these cases are ignored. Any fix that addresses this issue should also make sure these cases are addressed in the subsystem loading and unloading code. This patch: Make subsys[] able to be dynamically populated to support modular subsystems This patch reworks the way the subsys[] array is used so that subsystems can register themselves after boot time, and enables the internals of cgroups to be able to handle when subsystems are not present or may appear/disappear. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d7b9fff711d5e8db8c844161c684017e556c38a0 |
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11-Mar-2010 |
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> |
cgroup: introduce coalesce css_get() and css_put() Current css_get() and css_put() increment/decrement css->refcnt one by one. This patch add a new function __css_get(), which takes "count" as a arg and increment the css->refcnt by "count". And this patch also add a new arg("count") to __css_put() and change the function to decrement the css->refcnt by "count". These coalesce version of __css_get()/__css_put() will be used to improve performance of memcg's moving charge feature later, where instead of calling css_get()/css_put() repeatedly, these new functions will be used. No change is needed for current users of css_get()/css_put(). Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2468c7234b366eeb799ee0648cb58f9cba394a54 |
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11-Mar-2010 |
Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> |
cgroup: introduce cancel_attach() Add cancel_attach() operation to struct cgroup_subsys. cancel_attach() can be used when can_attach() operation prepares something for the subsys, but we should rollback what can_attach() operation has prepared if attach task fails after we've succeeded in can_attach(). Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c50cc75271759373bd89a036eec4d4269b291616 |
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25-Feb-2010 |
Ingo Molnar <mingo@elte.hu> |
sched, cgroups: Fix module export I have exported it in d11c563 - but cgroups.c did not have module.h included ... Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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d11c563dd20ff35da5652c3e1c989d9e10e1d6d0 |
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23-Feb-2010 |
Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
sched: Use lockdep-based checking on rcu_dereference() Update the rcu_dereference() usages to take advantage of the new lockdep-based checking. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> [ -v2: fix allmodconfig missing symbol export build failure on x86 ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
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4528fd0595847c2078b59f24800e751c2d6b7e41 |
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02-Feb-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix to return errno in a failure path In cgroup_create(), if alloc_css_id() returns failure, the errno is not propagated to userspace, so mkdir will fail silently. To trigger this bug, we mount blkio (or memory subsystem), and create more then 65534 cgroups. (The number of cgroups is limited to 65535 if a subsystem has use_id == 1) # mount -t cgroup -o blkio xxx /mnt # for ((i = 0; i < 65534; i++)); do mkdir /mnt/$i; done # mkdir /mnt/65534 (should return ENOSPC) # Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bd4f490a079730aadfaf9a728303ea0135c01945 |
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08-Jan-2010 |
Dave Anderson <anderson@redhat.com> |
cgroups: fix 2.6.32 regression causing BUG_ON() in cgroup_diput() The LTP cgroup test suite generates a "kernel BUG at kernel/cgroup.c:790!" here in cgroup_diput(): /* * if we're getting rid of the cgroup, refcount should ensure * that there are no pidlists left. */ BUG_ON(!list_empty(&cgrp->pidlists)); The cgroup pidlist rework in 2.6.32 generates the BUG_ON, which is caused when pidlist_array_load() calls cgroup_pidlist_find(): (1) if a matching cgroup_pidlist is found, it down_write's the mutex of the pre-existing cgroup_pidlist, and increments its use_count. (2) if no matching cgroup_pidlist is found, then a new one is allocated, it down_write's its mutex, and the use_count is set to 0. (3) the matching, or new, cgroup_pidlist gets returned back to pidlist_array_load(), which increments its use_count -- regardless whether new or pre-existing -- and up_write's the mutex. So if a matching list is ever encountered by cgroup_pidlist_find() during the life of a cgroup directory, it results in an inflated use_count value, preventing it from ever getting released by cgroup_release_pid_array(). Then if the directory is subsequently removed, cgroup_diput() hits the BUG_ON() when it finds that the directory's cgroup is still populated with a pidlist. The patch simply removes the use_count increment when a matching pidlist is found by cgroup_pidlist_find(), because it gets bumped by the calling pidlist_array_load() function while still protected by the list's mutex. Signed-off-by: Dave Anderson <anderson@redhat.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Paul Menage <menage@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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478988d3b28e98a31e0cfe24e011e28ba0f3cf0d |
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27-Oct-2009 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
cgroup: fix strstrip() misuse cgroup_write_X64() and cgroup_write_string() ignore the return value of strstrip(). it makes small inconsistent behavior. example: ========================= # cd /mnt/cgroup/hoge # cat memory.swappiness 60 # echo "59 " > memory.swappiness # cat memory.swappiness 59 # echo " 58" > memory.swappiness bash: echo: write error: Invalid argument This patch fixes it. Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3dece8347df6a16239fab10dadb370854f1c969c |
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02-Oct-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroup: catch bad css refcnt at css_put __css_put() doesn't check a bug as refcnt goes to minus. I think it should be caught. This patch adds a check for it. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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828c09509b9695271bcbdc53e9fc9a6a737148d2 |
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02-Oct-2009 |
Alexey Dobriyan <adobriyan@gmail.com> |
const: constify remaining file_operations [akpm@linux-foundation.org: fix KVM] Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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be367d09927023d081f9199665c8500f69f14d22 |
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24-Sep-2009 |
Ben Blum <bblum@google.com> |
cgroups: let ss->can_attach and ss->attach do whole threadgroups at a time Alter the ss->can_attach and ss->attach functions to be able to deal with a whole threadgroup at a time, for use in cgroup_attach_proc. (This is a pre-patch to cgroup-procs-writable.patch.) Currently, new mode of the attach function can only tell the subsystem about the old cgroup of the threadgroup leader. No subsystem currently needs that information for each thread that's being moved, but if one were to be added (for example, one that counts tasks within a group) this bit would need to be reworked a bit to tell the subsystem the right information. [hidave.darkstar@gmail.com: fix build] Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dave Young <hidave.darkstar@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c378369d8b4fa516ff2b1e79c3eded4e0e955ebb |
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24-Sep-2009 |
Ben Blum <bblum@google.com> |
cgroups: change css_set freeing mechanism to be under RCU Changes css_set freeing mechanism to be under RCU This is a prepatch for making the procs file writable. In order to free the old css_sets for each task to be moved as they're being moved, the freeing mechanism must be RCU-protected, or else we would have to have a call to synchronize_rcu() for each task before freeing its old css_set. Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d1d9fd3308fdef6b4bf564fa3d6cfe35b68b50bc |
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24-Sep-2009 |
Ben Blum <bblum@google.com> |
cgroups: use vmalloc for large cgroups pidlist allocations Separates all pidlist allocation requests to a separate function that judges based on the requested size whether or not the array needs to be vmalloced or can be gotten via kmalloc, and similar for kfree/vfree. Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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72a8cb30d10d4041c455a7054607a7d519167c87 |
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24-Sep-2009 |
Ben Blum <bblum@google.com> |
cgroups: ensure correct concurrent opening/reading of pidlists across pid namespaces Previously there was the problem in which two processes from different pid namespaces reading the tasks or procs file could result in one process seeing results from the other's namespace. Rather than one pidlist for each file in a cgroup, we now keep a list of pidlists keyed by namespace and file type (tasks versus procs) in which entries are placed on demand. Each pidlist has its own lock, and that the pidlists themselves are passed around in the seq_file's private pointer means we don't have to touch the cgroup or its master list except when creating and destroying entries. Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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102a775e3647628727ae83a9a6abf0564c3ca7cb |
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24-Sep-2009 |
Ben Blum <bblum@google.com> |
cgroups: add a read-only "procs" file similar to "tasks" that shows only unique tgids struct cgroup used to have a bunch of fields for keeping track of the pidlist for the tasks file. Those are now separated into a new struct cgroup_pidlist, of which two are had, one for procs and one for tasks. The way the seq_file operations are set up is changed so that just the pidlist struct gets passed around as the private data. Interface example: Suppose a multithreaded process has pid 1000 and other threads with ids 1001, 1002, 1003: $ cat tasks 1000 1001 1002 1003 $ cat cgroup.procs 1000 $ Signed-off-by: Ben Blum <bblum@google.com> Signed-off-by: Paul Menage <menage@google.com> Acked-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8f3ff20862cfcb85500a2bb55ee64622bd59fd0c |
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24-Sep-2009 |
Paul Menage <menage@google.com> |
cgroups: revert "cgroups: fix pid namespace bug" The following series adds a "cgroup.procs" file to each cgroup that reports unique tgids rather than pids, and allows all threads in a threadgroup to be atomically moved to a new cgroup. The subsystem "attach" interface is modified to support attaching whole threadgroups at a time, which could introduce potential problems if any subsystem were to need to access the old cgroup of every thread being moved. The attach interface may need to be revised if this becomes the case. Also added is functionality for read/write locking all CLONE_THREAD fork()ing within a threadgroup, by means of an rwsem that lives in the sighand_struct, for per-threadgroup-ness and also for sharing a cacheline with the sighand's atomic count. This scheme should introduce no extra overhead in the fork path when there's no contention. The final patch reveals potential for a race when forking before a subsystem's attach function is called - one potential solution in case any subsystem has this problem is to hang on to the group's fork mutex through the attach() calls, though no subsystem yet demonstrates need for an extended critical section. This patch: Revert commit 096b7fe012d66ed55e98bc8022405ede0cc80e96 Author: Li Zefan <lizf@cn.fujitsu.com> AuthorDate: Wed Jul 29 15:04:04 2009 -0700 Commit: Linus Torvalds <torvalds@linux-foundation.org> CommitDate: Wed Jul 29 19:10:35 2009 -0700 cgroups: fix pid namespace bug This is in preparation for some clashing cgroups changes that subsume the original commit's functionaliy. The original commit fixed a pid namespace bug which Ben Blum fixed independently (in the same way, but with different code) as part of a series of patches. I played around with trying to reconcile Ben's patch series with Li's patch, but concluded that it was simpler to just revert Li's, given that Ben's patch series contained essentially the same fix. Signed-off-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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2c6ab6d200827e1c41dc71fff3a2ac7473f51777 |
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24-Sep-2009 |
Paul Menage <menage@google.com> |
cgroups: allow cgroup hierarchies to be created with no bound subsystems This patch removes the restriction that a cgroup hierarchy must have at least one bound subsystem. The mount option "none" is treated as an explicit request for no bound subsystems. A hierarchy with no subsystems can be useful for plain task tracking, and is also a step towards the support for multiply-bindable subsystems. As part of this change, the hierarchy id is no longer calculated from the bitmask of subsystems in the hierarchy (since this is not guaranteed to be unique) but is allocated via an ida. Reference counts on cgroups from css_set objects are now taken explicitly one per hierarchy, rather than one per subsystem. Example usage: mount -t cgroup -o none,name=foo cgroup /mnt/cgroup Based on the "no-op"/"none" subsystem concept proposed by kamezawa.hiroyu@jp.fujitsu.com Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7717f7ba92de485bce8293419a20ffef130f4286 |
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24-Sep-2009 |
Paul Menage <menage@google.com> |
cgroups: add a back-pointer from struct cg_cgroup_link to struct cgroup Currently the cgroups code makes the assumption that the subsystem pointers in a struct css_set uniquely identify the hierarchy->cgroup mappings associated with the css_set; and there's no way to directly identify the associated set of cgroups other than by indirecting through the appropriate subsystem state pointers. This patch removes the need for that assumption by adding a back-pointer from struct cg_cgroup_link object to its associated cgroup; this allows the set of cgroups to be determined by traversing the cg_links list in the struct css_set. Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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fe6934354f8e287275500cd6ec73826d4d6ad457 |
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24-Sep-2009 |
Paul Menage <menage@google.com> |
cgroups: move the cgroup debug subsys into cgroup.c to access internal state While it's architecturally clean to have the cgroup debug subsystem be completely independent of the cgroups framework, it limits its usefulness for debugging the contents of internal data structures. Move the debug subsystem code into the scope of all the cgroups data structures to make more detailed debugging possible. Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c6d57f3312a6619d47c5557b5f6154a74d04ff80 |
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24-Sep-2009 |
Paul Menage <menage@google.com> |
cgroups: support named cgroups hierarchies To simplify referring to cgroup hierarchies in mount statements, and to allow disambiguation in the presence of empty hierarchies and multiply-bindable subsystems this patch adds support for naming a new cgroup hierarchy via the "name=" mount option A pre-existing hierarchy may be specified by either name or by subsystems; a hierarchy's name cannot be changed by a remount operation. Example usage: # To create a hierarchy called "foo" containing the "cpu" subsystem mount -t cgroup -oname=foo,cpu cgroup /mnt/cgroup1 # To mount the "foo" hierarchy on a second location mount -t cgroup -oname=foo cgroup /mnt/cgroup2 Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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34f77a90f79fca31802c2e942bd73f7f557fe28c |
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24-Sep-2009 |
Xiaotian Feng <dfeng@redhat.com> |
cgroups: make unlock sequence in cgroup_get_sb consistent Make the last unlock sequence consistent with previous unlock sequeue. Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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88e9d34c727883d7d6f02cf1475b3ec98b8480c7 |
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23-Sep-2009 |
James Morris <jmorris@namei.org> |
seq_file: constify seq_operations Make all seq_operations structs const, to help mitigate against revectoring user-triggerable function pointers. This is derived from the grsecurity patch, although generated from scratch because it's simpler than extracting the changes from there. Signed-off-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Acked-by: Casey Schaufler <casey@schaufler-ca.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6e1d5dcc2bbbe71dbf010c747e15739bef6b7218 |
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22-Sep-2009 |
Alexey Dobriyan <adobriyan@gmail.com> |
const: mark remaining inode_operations as const Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b87221de6a4934eda856475a0065688d12973a04 |
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22-Sep-2009 |
Alexey Dobriyan <adobriyan@gmail.com> |
const: mark remaining super_operations const Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d993831fa7ffeb89e994f046f93eeb09ec91df08 |
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12-Jun-2009 |
Jens Axboe <jens.axboe@oracle.com> |
writeback: add name to backing_dev_info This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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887032670d47366a8c8f25396ea7c14b7b2cc620 |
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30-Jul-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroup avoid permanent sleep at rmdir After commit ec64f51545fffbc4cb968f0cea56341a4b07e85a ("cgroup: fix frequent -EBUSY at rmdir"), cgroup's rmdir (especially against memcg) doesn't return -EBUSY by temporary ref counts. That commit expects all refs after pre_destroy() is temporary but...it wasn't. Then, rmdir can wait permanently. This patch tries to fix that and change followings. - set CGRP_WAIT_ON_RMDIR flag before pre_destroy(). - clear CGRP_WAIT_ON_RMDIR flag when the subsys finds racy case. if there are sleeping ones, wakes them up. - rmdir() sleeps only when CGRP_WAIT_ON_RMDIR flag is set. Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reviewed-by: Paul Menage <menage@google.com> Acked-by: Balbir Sigh <balbir@linux.vnet.ibm.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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096b7fe012d66ed55e98bc8022405ede0cc80e96 |
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30-Jul-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix pid namespace bug The bug was introduced by commit cc31edceee04a7b87f2be48f9489ebb72d264844 ("cgroups: convert tasks file to use a seq_file with shared pid array"). We cache a pid array for all threads that are opening the same "tasks" file, but the pids in the array are always from the namespace of the last process that opened the file, so all other threads will read pids from that namespace instead of their own namespaces. To fix it, we maintain a list of pid arrays, which is keyed by pid_ns. The list will be of length 1 at most time. Reported-by: Paul Menage <menage@google.com> Idea-by: Paul Menage <menage@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Serge Hallyn <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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f9ab5b5b0f5be506640321d710b0acd3dca6154a |
|
18-Jun-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: forbid noprefix if mounting more than just cpuset subsystem The 'noprefix' option was introduced for backwards-compatibility of cpuset, but actually it can be used when mounting other subsystems. This results in possibility of name collision, and now the collision can really happen, because we have 'stat' file in both memory and cpuacct subsystem: # mount -t cgroup -o noprefix,memory,cpuacct xxx /mnt Cgroup will happily mount the 2 subsystems, but only 'stat' file of memory subsys can be seen. We don't want users to use nopreifx, and also want to avoid name collision, so we change to allow noprefix only if mounting just the cpuset subsystem. [akpm@linux-foundation.org: fix shift for cpuset_subsys_id >= 32] Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: Dhaval Giani <dhaval@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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337eb00a2c3a421999c39c94ce7e33545ee8baa7 |
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12-May-2009 |
Alessio Igor Bogani <abogani@texware.it> |
Push BKL down into ->remount_fs() [xfs, btrfs, capifs, shmem don't need BKL, exempt] Signed-off-by: Alessio Igor Bogani <abogani@texware.it> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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6f5bbff9a1b7d6864a495763448a363bbfa96324 |
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06-May-2009 |
Al Viro <viro@zeniv.linux.org.uk> |
Convert obvious places to deactivate_locked_super() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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0b7f569e45bb6be142d87017030669a6a7d327a1 |
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03-Apr-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memcg: fix OOM killer under memcg This patch tries to fix OOM Killer problems caused by hierarchy. Now, memcg itself has OOM KILL function (in oom_kill.c) and tries to kill a task in memcg. But, when hierarchy is used, it's broken and correct task cannot be killed. For example, in following cgroup /groupA/ hierarchy=1, limit=1G, 01 nolimit 02 nolimit All tasks' memory usage under /groupA, /groupA/01, groupA/02 is limited to groupA's 1Gbytes but OOM Killer just kills tasks in groupA. This patch provides makes the bad process be selected from all tasks under hierarchy. BTW, currently, oom_jiffies is updated against groupA in above case. oom_jiffies of tree should be updated. To see how oom_jiffies is used, please check mem_cgroup_oom_called() callers. [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: const fix] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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0670e08bdfc67272f8c3087030417465629b8073 |
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03-Apr-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: don't change release_agent when remount failed Remount can fail in either case: - wrong mount options is specified, or option 'noprefix' is changed. - a to-be-added subsys is already mounted/active. When using remount to change 'release_agent', for the above former failure case, remount will return errno with release_agent unchanged, but for the latter case, remount will return EBUSY with relase_agent changed, which is unexpected I think: # mount -t cgroup -o cpu xxx /cgrp1 # mount -t cgroup -o cpuset,release_agent=agent1 yyy /cgrp2 # cat /cgrp2/release_agent agent1 # mount -t cgroup -o remount,cpuset,noprefix,release_agent=agent2 yyy /cgrp2 mount: /cgrp2 not mounted already, or bad option # cat /cgrp2/release_agent agent1 <-- ok # mount -t cgroup -o remount,cpu,cpuset,release_agent=agent2 yyy /cgrp2 mount: /cgrp2 is busy # cat /cgrp2/release_agent agent2 <-- unexpected! Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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099fca3225b39f7a3ed853036038054172b55581 |
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03-Apr-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: show correct file mode We have some read-only files and write-only files, but currently they are all set to 0644, which is counter-intuitive and cause trouble for some cgroup tools like libcgroup. This patch adds 'mode' to struct cftype to allow cgroup subsys to set it's own files' file mode, and for the most cases cft->mode can be default to 0 and cgroup will figure out proper mode. Acked-by: Paul Menage <menage@google.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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66bdc9cfc77ba89a9ee6c82d28375b646ab4bb1d |
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03-Apr-2009 |
Jesper Juhl <jj@chaosbits.net> |
kernel/cgroup.c: kfree(NULL) is legal Reduces object file size a bit: Before: $ size kernel/cgroup.o text data bss dec hex filename 21593 7804 4924 34321 8611 kernel/cgroup.o After: $ size kernel/cgroup.o text data bss dec hex filename 21537 7744 4924 34205 859d kernel/cgroup.o Signed-off-by: Jesper Juhl <jj@chaosbits.net> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ec64f51545fffbc4cb968f0cea56341a4b07e85a |
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03-Apr-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroup: fix frequent -EBUSY at rmdir In following situation, with memory subsystem, /groupA use_hierarchy==1 /01 some tasks /02 some tasks /03 some tasks /04 empty When tasks under 01/02/03 hit limit on /groupA, hierarchical reclaim is triggered and the kernel walks tree under groupA. In this case, rmdir /groupA/04 fails with -EBUSY frequently because of temporal refcnt from the kernel. In general. cgroup can be rmdir'd if there are no children groups and no tasks. Frequent fails of rmdir() is not useful to users. (And the reason for -EBUSY is unknown to users.....in most cases) This patch tries to modify above behavior, by - retries if css_refcnt is got by someone. - add "return value" to pre_destroy() and allows subsystem to say "we're really busy!" Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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38460b48d06440de46b34cb778bd6c4855030754 |
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03-Apr-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroup: CSS ID support Patch for Per-CSS(Cgroup Subsys State) ID and private hierarchy code. This patch attaches unique ID to each css and provides following. - css_lookup(subsys, id) returns pointer to struct cgroup_subysys_state of id. - css_get_next(subsys, id, rootid, depth, foundid) returns the next css under "root" by scanning When cgroup_subsys->use_id is set, an id for css is maintained. The cgroup framework only parepares - css_id of root css for subsys - id is automatically attached at creation of css. - id is *not* freed automatically. Because the cgroup framework don't know lifetime of cgroup_subsys_state. free_css_id() function is provided. This must be called by subsys. There are several reasons to develop this. - Saving space .... For example, memcg's swap_cgroup is array of pointers to cgroup. But it is not necessary to be very fast. By replacing pointers(8bytes per ent) to ID (2byes per ent), we can reduce much amount of memory usage. - Scanning without lock. CSS_ID provides "scan id under this ROOT" function. By this, scanning css under root can be written without locks. ex) do { rcu_read_lock(); next = cgroup_get_next(subsys, id, root, &found); /* check sanity of next here */ css_tryget(); rcu_read_unlock(); id = found + 1 } while(...) Characteristics: - Each css has unique ID under subsys. - Lifetime of ID is controlled by subsys. - css ID contains "ID" and "Depth in hierarchy" and stack of hierarchy - Allowed ID is 1-65535, ID 0 is UNUSED ID. Design Choices: - scan-by-ID v.s. scan-by-tree-walk. As /proc's pid scan does, scan-by-ID is robust when scanning is done by following kind of routine. scan -> rest a while(release a lock) -> conitunue from interrupted memcg's hierarchical reclaim does this. - When subsys->use_id is set, # of css in the system is limited to 65535. [bharata@linux.vnet.ibm.com: remove rcu_read_lock() from css_get_next()] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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313e924c0852943e67335fad9d2608701f0dfe8e |
|
03-Apr-2009 |
Grzegorz Nosek <root@localdomain.pl> |
cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups The ns_proxy cgroup allows moving processes to child cgroups only one level deep at a time. This commit relaxes this restriction and makes it possible to attach tasks directly to grandchild cgroups, e.g.: ($pid is in the root cgroup) echo $pid > /cgroup/CG1/CG2/tasks Previously this operation would fail with -EPERM and would have to be performed as two steps: echo $pid > /cgroup/CG1/tasks echo $pid > /cgroup/CG1/CG2/tasks Also, the target cgroup no longer needs to be empty to move a task there. Signed-off-by: Grzegorz Nosek <root@localdomain.pl> Acked-by: Serge Hallyn <serue@us.ibm.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a3ec947c85ec339884b30ef6a08133e9311fdae1 |
|
04-Mar-2009 |
Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> |
vfs: simple_set_mnt() should return void simple_set_mnt() is defined as returning 'int' but always returns 0. Callers assume simple_set_mnt() never fails and don't properly cleanup if it were to _ever_ fail. For instance, get_sb_single() and get_sb_nodev() should: up_write(sb->s_unmount); deactivate_super(sb); if simple_set_mnt() fails. Since simple_set_mnt() never fails, would be cleaner if it did not return anything. [akpm@linux-foundation.org: fix build] Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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3ba13d179e8c24c68eac32b93593a6b10fcd1572 |
|
20-Feb-2009 |
Al Viro <viro@zeniv.linux.org.uk> |
constify dentry_operations: rest Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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67e055d144c5b2acdc1c63811fde031263bf92c5 |
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18-Feb-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix possible use after free In cgroup_kill_sb(), root is freed before sb is detached from the list, so another sget() may find this sb and call cgroup_test_super(), which will access the root that has been freed. Reported-by: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cfebe563bd0a3ff97e1bc167123120d59c7a84db |
|
11-Feb-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix lockdep subclasses overflow I enabled all cgroup subsystems when compiling kernel, and then: # mount -t cgroup -o net_cls xxx /mnt # mkdir /mnt/0 This showed up immediately: BUG: MAX_LOCKDEP_SUBCLASSES too low! turning off the locking correctness validator. It's caused by the cgroup hierarchy lock: for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { struct cgroup_subsys *ss = subsys[i]; if (ss->root == root) mutex_lock_nested(&ss->hierarchy_mutex, i); } Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but MAX_LOCKDEP_SUBCLASSES is 8. This patch uses different lockdep keys for different subsystems. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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839ec5452ebfd5905b9c69b20ceb640903a8ea1a |
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29-Jan-2009 |
Paul Menage <menage@google.com> |
cgroup: fix root_count when mount fails due to busy subsystem root_count was being incremented in cgroup_get_sb() after all error checking was complete, but decremented in cgroup_kill_sb(), which can be called on a superblock that we gave up on due to an error. This patch changes cgroup_kill_sb() to only decrement root_count if the root was previously linked into the list of roots. Signed-off-by: Paul Menage <menage@google.com> Tested-by: Serge Hallyn <serue@us.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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804b3c28a4e4fa1c224571bf76edb534b9c4b1ed |
|
29-Jan-2009 |
Paul Menage <menage@google.com> |
cgroups: add cpu_relax() calls in css_tryget() and cgroup_clear_css_refs() css_tryget() and cgroup_clear_css_refs() contain polling loops; these loops should have cpu_relax calls in them to reduce cross-cache traffic. Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1404f06565ee89e0ce04d4a5859c00b0e3a0dc8d |
|
29-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix lock inconsistency in cgroup_clone() I fixed a bug in cgroup_clone() in Linus' tree in commit 7b574b7 ("cgroups: fix a race between cgroup_clone and umount") without noticing there was a cleanup patch in -mm tree that should be rebased (now commit 104cbd5, "cgroups: use task_lock() for access tsk->cgroups safe in cgroup_clone()"), thus resulted in lock inconsistency. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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baef99a08a2e23d9386b47e53fa5f0d44fc98f66 |
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29-Jan-2009 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroups: use hierarchy mutex in creation failure path Now, cgrp->sibling is handled under hierarchy mutex. error route should do so, too. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Acked-by Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e7c5ec9193d32b9559a3bb8893ceedbda85201ff |
|
08-Jan-2009 |
Paul Menage <menage@google.com> |
cgroups: add css_tryget() Add css_tryget(), that obtains a counted reference on a CSS. It is used in situations where the caller has a "weak" reference to the CSS, i.e. one that does not protect the cgroup from removal via a reference count, but would instead be cleaned up by a destroy() callback. css_tryget() will return true on success, or false if the cgroup is being removed. This is similar to Kamezawa Hiroyuki's patch from a week or two ago, but with the difference that in the event of css_tryget() racing with a cgroup_rmdir(), css_tryget() will only return false if the cgroup really does get removed. This implementation is done by biasing css->refcnt, so that a refcnt of 1 means "releasable" and 0 means "released or releasing". In the event of a race, css_tryget() distinguishes between "released" and "releasing" by checking for the CSS_REMOVED flag in css->flags. Signed-off-by: Paul Menage <menage@google.com> Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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999cd8a450f8f93701669a61cac4d3b19eca07e8 |
|
08-Jan-2009 |
Paul Menage <menage@google.com> |
cgroups: add a per-subsystem hierarchy_mutex These patches introduce new locking/refcount support for cgroups to reduce the need for subsystems to call cgroup_lock(). This will ultimately allow the atomicity of cgroup_rmdir() (which was removed recently) to be restored. These three patches give: 1/3 - introduce a per-subsystem hierarchy_mutex which a subsystem can use to prevent changes to its own cgroup tree 2/3 - use hierarchy_mutex in place of calling cgroup_lock() in the memory controller 3/3 - introduce a css_tryget() function similar to the one recently proposed by Kamezawa, but avoiding spurious refcount failures in the event of a race between a css_tryget() and an unsuccessful cgroup_rmdir() Future patches will likely involve: - using hierarchy mutex in place of cgroup_lock() in more subsystems where appropriate - restoring the atomicity of cgroup_rmdir() with respect to cgroup_create() This patch: Add a hierarchy_mutex to the cgroup_subsys object that protects changes to the hierarchy observed by that subsystem. It is taken by the cgroup subsystem (in addition to cgroup_mutex) for the following operations: - linking a cgroup into that subsystem's cgroup tree - unlinking a cgroup from that subsystem's cgroup tree - moving the subsystem to/from a hierarchy (including across the bind() callback) Thus if the subsystem holds its own hierarchy_mutex, it can safely traverse its own hierarchy. Signed-off-by: Paul Menage <menage@google.com> Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a47295e6bc42ad35f9c15ac66f598aa24debd4e2 |
|
08-Jan-2009 |
Paul Menage <menage@google.com> |
cgroups: make cgroup_path() RCU-safe Fix races between /proc/sched_debug by freeing cgroup objects via an RCU callback. Thus any cgroup reference obtained from an RCU-safe source will remain valid during the RCU section. Since dentries are also RCU-safe, this allows us to traverse up the tree safely. Additionally, make cgroup_path() check for a NULL cgrp->dentry to avoid trying to report a path for a partially-created cgroup. [lizf@cn.fujitsu.com: call deactive_super() in cgroup_diput()] Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Tested-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e7b80bb695a5b64c92e314838e083b2f3bdf29b2 |
|
08-Jan-2009 |
Gowrishankar M <gowrishankar.m@in.ibm.com> |
cgroups: skip processes from other namespaces when listing a cgroup Once tasks are populated from system namespace inside cgroup, container replaces other namespace task with 0 while listing tasks, inside container. Though this is expected behaviour from container end, there is no use of showing unwanted 0s. In this patch, we check if a process is in same namespace before loading into pid array. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Gowrishankar M <gowrishankar.m@in.ibm.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
c12f65d4396e05c51ce3af7f159ead98574a587c |
|
08-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: introduce link_css_set() to remove duplicate code Add a common function link_css_set() to link a css_set to a cgroup. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
33a68ac1c1b695216e873ee12e819adbe73e4d9f |
|
08-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: add inactive subsystems to rootnode.subsys_list Though for an inactive hierarchy, we have subsys->root == &rootnode, but rootnode's subsys_list is always empty. This conflicts with the code in find_css_set(): for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) { ... if (ss->root->subsys_list.next == &ss->sibling) { ... } } if (list_empty(&rootnode.subsys_list)) { ... } The above code assumes rootnode.subsys_list links all inactive hierarchies. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e5f6a8609bab0c2d7543ab1505105e011832afd7 |
|
08-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: make root_list contains active hierarchies only Don't link rootnode to the root list, so root_list contains active hierarchies only as the comment indicates. And rename for_each_root() to for_each_active_root(). Also remove redundant check in cgroup_kill_sb(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
7534432dcc3c654a8671b6b0cdffd1dbdbc73074 |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: remove rcu_read_lock() in cgroupstats_build() cgroup_iter_* do not need rcu_read_lock(). In cgroup_enable_task_cg_lists(), do_each_thread() and while_each_thread() are protected by RCU, it's OK, for write_lock(&css_set_lock) implies rcu_read_lock() in non-RT kernel. If we need explicit rcu_read_lock(), we should add rcu_read_lock() in cgroup_enable_task_cg_lists(), not cgroup_iter_*. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
77efecd9e0526327548152df715ab8644ecb5ba0 |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: call find_css_set() safely in cgroup_attach_task() In cgroup_attach_task(), tsk maybe exit when we call find_css_set(). and find_css_set() will access to invalid css_set. This patch increases the count before get_css_set(), and decreases it after find_css_set(). NOTE: css_set's refcount is also taskcount, after this patch applied, taskcount may be off-by-one WHEN cgroup_lock() is not held. but I reviewed other code which use taskcount, they are still correct. No regression found by reviewing and simply testing. So I do not use two counters in css_set. (one counter for taskcount, the other for refcount. like struct mm_struct) If this fix cause regression, we will use two counters in css_set. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
104cbd55377029e70fc2cee01089e84b9c36e5dc |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: use task_lock() for access tsk->cgroups safe in cgroup_clone() Use task_lock() protect tsk->cgroups and get_css_set(tsk->cgroups). Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
b2aa30f7bb381e04c93eed106089ba55553955f1 |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: don't put struct cgroupfs_root protected by RCU We don't access struct cgroupfs_root in fast path, so we should not put struct cgroupfs_root protected by RCU But the comment in struct cgroup_subsys.root confuse us. struct cgroup_subsys.root is used in these places: 1 find_css_set(): if (ss->root->subsys_list.next == &ss->sibling) 2 rebind_subsystems(): if (ss->root != &rootnode) rcu_assign_pointer(ss->root, root); rcu_assign_pointer(subsys[i]->root, &rootnode); 3 cgroup_has_css_refs(): if (ss->root != cgrp->root) 4 cgroup_init_subsys(): ss->root = &rootnode; 5 proc_cgroupstats_show(): ss->name, ss->root->subsys_bits, ss->root->number_of_cgroups, !ss->disabled); 6 cgroup_clone(): root = subsys->root; if ((root != subsys->root) || All these place we have held cgroup_lock() or we don't dereference to struct cgroupfs_root. It's means wo don't need RCU when use struct cgroup_subsys.root, and we should not put struct cgroupfs_root protected by RCU. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
2019f634ce5904c19eba4e86f51b1a119a53a9f1 |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: fix cgroup_iter_next() bug We access res->cgroups without the task_lock(), so res->cgroups may be changed. it's unreliable, and "if (l == &res->cgroups->tasks)" may be false forever. We don't need add any lock for fixing this bug. we just access to struct css_set by struct cg_cgroup_link, not by struct task_struct. Since we hold css_set_lock, struct cg_cgroup_link is reliable. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
b12b533fa523e94e0cc9dc23274ae4f9439f1313 |
|
08-Jan-2009 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: add lock for child->cgroups in cgroup_post_fork() When cgroup_post_fork() is called, child is seen by find_task_by_vpid(), so child->cgroups maybe be changed, It'll incorrect. child->cgroups<old>'s refcnt is decreased child->cgroups<new>'s refcnt is increased but child->cg_list is added to child->cgroups<old>'s list. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
75139b8274c3e30354daea623f14b43a482a0bb5 |
|
08-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: remove some redundant NULL checks - In cgroup_clone(), if vfs_mkdir() returns successfully, dentry->d_fsdata will be the pointer to the newly created cgroup and won't be NULL. - a cgroup file's dentry->d_fsdata won't be NULL, guaranteed by cgroup_add_file(). - When walking through the subsystems of a cgroup_fs (using for_each_subsys), cgrp->subsys[ss->subsys_id] won't be NULL, guaranteed by cgroup_create(). (Also remove 2 unused variables in cgroup_rmdir(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e5991371ee0d1c0ce19e133c6f9075b49c5b4ae8 |
|
06-Jan-2009 |
Hugh Dickins <hugh@veritas.com> |
mm: remove cgroup_mm_owner_callbacks cgroup_mm_owner_callbacks() was brought in to support the memrlimit controller, but sneaked into mainline ahead of it. That controller has now been shelved, and the mm_owner_changed() args were inadequate for it anyway (they needed an mm pointer instead of a task pointer). Remove the dead code, and restore mm_update_next_owner() locking to how it was before: taking mmap_sem there does nothing for memcontrol.c, now the only user of mm->owner. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
56ff5efad96182f4d3cb3dc6b07396762c658f16 |
|
09-Dec-2008 |
Al Viro <viro@zeniv.linux.org.uk> |
zero i_uid/i_gid on inode allocation ... and don't bother in callers. Don't bother with zeroing i_blocks, while we are at it - it's already been zeroed. i_mode is not worth the effort; it has no common default value. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
|
7b574b7b0124ed344911f5d581e9bc2d83bbeb19 |
|
04-Jan-2009 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix a race between cgroup_clone and umount The race is calling cgroup_clone() while umounting the ns cgroup subsys, and thus cgroup_clone() might access invalid cgroup_fs, or kill_sb() is called after cgroup_clone() created a new dir in it. The BUG I triggered is BUG_ON(root->number_of_cgroups != 1); ------------[ cut here ]------------ kernel BUG at kernel/cgroup.c:1093! invalid opcode: 0000 [#1] SMP ... Process umount (pid: 5177, ti=e411e000 task=e40c4670 task.ti=e411e000) ... Call Trace: [<c0493df7>] ? deactivate_super+0x3f/0x51 [<c04a3600>] ? mntput_no_expire+0xb3/0xdd [<c04a3ab2>] ? sys_umount+0x265/0x2ac [<c04a3b06>] ? sys_oldumount+0xd/0xf [<c0403911>] ? sysenter_do_call+0x12/0x31 ... EIP: [<c0456e76>] cgroup_kill_sb+0x23/0xe0 SS:ESP 0068:e411ef2c ---[ end trace c766c1be3bf944ac ]--- Cc: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
20ca9b3f4c6dfa0af8dd5b18a64df17eb994b54d |
|
23-Dec-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: avoid accessing uninitialized data in failure path If cgroup_get_rootdir() failed, free_cg_links() will be called in the failure path, but tmp_cg_links hasn't been initialized at that time. I introduced this bug in the 2.6.27 merge window. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e368d3a836797ddf193b1ec18c97407a791d2451 |
|
23-Dec-2008 |
Sharyathi Nagesh <sharyath@in.ibm.com> |
cgroups: suppress bogus warning messages Remove spurious warning messages that are thrown onto the console during cgroup operations. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Sharyathi Nagesh <sharyathi@in.ibm.com> Acked-by: Serge E. Hallyn <serge@hallyn.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
307257cf475aac25db30b669987f13d90c934e3a |
|
15-Dec-2008 |
Paul Menage <menage@google.com> |
cgroups: fix a race between rmdir and remount When a cgroup is removed, it's unlinked from its parent's children list, but not actually freed until the last dentry on it is released (at which point cgrp->root->number_of_cgroups is decremented). Currently rebind_subsystems checks for the top cgroup's child list being empty in order to rebind subsystems into or out of a hierarchy - this can result in the set of subsystems bound to a hierarchy being removed-but-not-freed cgroup. The simplest fix for this is to forbid remounts that change the set of subsystems on a hierarchy that has removed-but-not-freed cgroups. This bug can be reproduced via: mkdir /mnt/cg mount -t cgroup -o ns,freezer cgroup /mnt/cg mkdir /mnt/cg/foo sleep 1h < /mnt/cg/foo & rmdir /mnt/cg/foo mount -t cgroup -o remount,ns,devices,freezer cgroup /mnt/cg kill $! Though the above will cause oops in -mm only but not mainline, but the bug can cause memory leak in mainline (and even oops) Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
33d283bef23132c48195eafc21449f8ba88fce6b |
|
20-Nov-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix a serious bug in cgroupstats Try this, and you'll get oops immediately: # cd Documentation/accounting/ # gcc -o getdelays getdelays.c # mount -t cgroup -o debug xxx /mnt # ./getdelays -C /mnt/tasks Because a normal file's dentry->d_fsdata is a pointer to struct cftype, not struct cgroup. After the patch, it returns EINVAL if we try to get cgroupstats from a normal file. Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
3fa59dfbc3b223f02c26593be69ce6fc9a940405 |
|
20-Nov-2008 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
cgroup: fix potential deadlock in pre_destroy As Balbir pointed out, memcg's pre_destroy handler has potential deadlock. It has following lock sequence. cgroup_mutex (cgroup_rmdir) -> pre_destroy -> mem_cgroup_pre_destroy-> force_empty -> cpu_hotplug.lock. (lru_add_drain_all-> schedule_work-> get_online_cpus) But, cpuset has following. cpu_hotplug.lock (call notifier) -> cgroup_mutex. (within notifier) Then, this lock sequence should be fixed. Considering how pre_destroy works, it's not necessary to holding cgroup_mutex() while calling it. As a side effect, we don't have to wait at this mutex while memcg's force_empty works.(it can be long when there are tons of pages.) Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
c69e8d9c01db2adc503464993c358901c9af9de4 |
|
14-Nov-2008 |
David Howells <dhowells@redhat.com> |
CRED: Use RCU to access another task's creds and to release a task's own creds Use RCU to access another task's creds and to release a task's own creds. This means that it will be possible for the credentials of a task to be replaced without another task (a) requiring a full lock to read them, and (b) seeing deallocated memory. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
|
b6dff3ec5e116e3af6f537d4caedcad6b9e5082a |
|
14-Nov-2008 |
David Howells <dhowells@redhat.com> |
CRED: Separate task security context from task_struct Separate the task security context from task_struct. At this point, the security data is temporarily embedded in the task_struct with two pointers pointing to it. Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in entry.S via asm-offsets. With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: James Morris <jmorris@namei.org>
|
76aac0e9a17742e60d408be1a706e9aaad370891 |
|
14-Nov-2008 |
David Howells <dhowells@redhat.com> |
CRED: Wrap task credential accesses in the core kernel Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-audit@redhat.com Cc: containers@lists.linux-foundation.org Cc: linux-mm@kvack.org Signed-off-by: James Morris <jmorris@namei.org>
|
24eb089950ce44603b30a3145a2c8520e2b55bb1 |
|
06-Nov-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: fix invalid cgrp->dentry before cgroup has been completely removed This fixes an oops when reading /proc/sched_debug. A cgroup won't be removed completely until finishing cgroup_diput(), so we shouldn't invalidate cgrp->dentry in cgroup_rmdir(). Otherwise, when a group is being removed while cgroup_path() gets called, we may trigger NULL dereference BUG. The bug can be reproduced: # cat test.sh #!/bin/sh mount -t cgroup -o cpu xxx /mnt for (( ; ; )) { mkdir /mnt/sub rmdir /mnt/sub } # ./test.sh & # cat /proc/sched_debug BUG: unable to handle kernel NULL pointer dereference at 00000038 IP: [<c045a47f>] cgroup_path+0x39/0x90 ... Call Trace: [<c0420344>] ? print_cfs_rq+0x6e/0x75d [<c0421160>] ? sched_debug_show+0x72d/0xc1e ... Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: <stable@kernel.org> [2.6.26.x, 2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
2077776641b6ffb0049f13018d2e162340ec51c7 |
|
21-Oct-2008 |
Stephen Rothwell <sfr@canb.auug.org.au> |
cgroup: remove unused variable /scratch/sfr/next/kernel/cgroup.c: In function 'cgroup_tasks_start': /scratch/sfr/next/kernel/cgroup.c:2107: warning: unused variable 'i' Introduced in commit cc31edceee04a7b87f2be48f9489ebb72d264844 "cgroups: convert tasks file to use a seq_file with shared pid array". Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
cc31edceee04a7b87f2be48f9489ebb72d264844 |
|
19-Oct-2008 |
Paul Menage <menage@google.com> |
cgroups: convert tasks file to use a seq_file with shared pid array Rather than pre-generating the entire text for the "tasks" file each time the file is opened, we instead just generate/update the array of process ids and use a seq_file to report these to userspace. All open file handles on the same "tasks" file can share a pid array, which may be updated any time that no thread is actively reading the array. By sharing the array, the potential for userspace to DoS the system by opening many handles on the same "tasks" file is removed. [Based on a patch by Lai Jiangshan, extended to use seq_file] Signed-off-by: Paul Menage <menage@google.com> Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
146aa1bd0511f88ddb4e92fafa2b8aad4f2f65f3 |
|
19-Oct-2008 |
Lai Jiangshan <laijs@cn.fujitsu.com> |
cgroups: fix probable race with put_css_set[_taskexit] and find_css_set put_css_set_taskexit may be called when find_css_set is called on other cpu. And the race will occur: put_css_set_taskexit side find_css_set side | atomic_dec_and_test(&kref->refcount) | /* kref->refcount = 0 */ | .................................................................... | read_lock(&css_set_lock) | find_existing_css_set | get_css_set | read_unlock(&css_set_lock); .................................................................... __release_css_set | .................................................................... | /* use a released css_set */ | [put_css_set is the same. But in the current code, all put_css_set are put into cgroup mutex critical region as the same as find_css_set.] [akpm@linux-foundation.org: repair comments] [menage@google.com: eliminate race in css_set refcounting] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
9363b9f23c9cc36cc8ef6c05fdf879ee4a96ae92 |
|
16-Oct-2008 |
Balbir Singh <balbir@linux.vnet.ibm.com> |
memrlimit: cgroup mm owner callback changes to add task info This patch adds an additional field to the mm_owner callbacks. This field is required to get to the mm that changed. Hold mmap_sem in write mode before calling the mm_owner_changed callback [hugh@veritas.com: fix mmap_sem deadlock] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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31a78f23bac0069004e69f98808b6988baccb6b6 |
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29-Sep-2008 |
Balbir Singh <balbir@linux.vnet.ibm.com> |
mm owner: fix race between swapoff and exit There's a race between mm->owner assignment and swapoff, more easily seen when task slab poisoning is turned on. The condition occurs when try_to_unuse() runs in parallel with an exiting task. A similar race can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats> or ptrace or page migration. CPU0 CPU1 try_to_unuse looks at mm = task0->mm increments mm->mm_users task 0 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task0->mm) mm_update_next_owner() leaves mmput(mm) decrements mm->mm_users task0 freed dereferencing mm->owner fails The fix is to notify the subsystem via mm_owner_changed callback(), if no new owner is found, by specifying the new task as NULL. Jiri Slaby: mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but must be set after that, so as not to pass NULL as old owner causing oops. Daisuke Nishimura: mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task() and its callers need to take account of this situation to avoid oops. Hugh Dickins: Lockdep warning and hang below exec_mmap() when testing these patches. exit_mm() up_reads mmap_sem before calling mm_update_next_owner(), so exec_mmap() now needs to do the same. And with that repositioning, there's now no point in mm_need_new_owner() allowing for NULL mm. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
55b6fd0162ace1e0f1b52c8c092565c115127ef6 |
|
30-Jul-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: uninline cgroup_has_css_refs() It's not small enough, and has 2 call sites. text data bss dec hex filename 12813 1676 4832 19321 4b79 cgroup.o.orig 12775 1676 4832 19283 4b53 cgroup.o Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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36553434f475a84b653e25e74490ee8df43b86d5 |
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30-Jul-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: remove duplicate code in allocate_cg_link() - just call free_cg_links() in allocate_cg_links() - the list will get initialized in allocate_cg_links(), so don't init it twice Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5a3eb9f6b7c598529f832b8baa6458ab1cbab2c6 |
|
30-Jul-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix possible memory leak There's a leak if copy_from_user() returns failure. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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3f8206d496e9e9495afb1d4e70d29712b4d403c9 |
|
26-Jul-2008 |
Al Viro <viro@zeniv.linux.org.uk> |
[PATCH] get rid of indirect users of namei.h fs.h needs path.h, not namei.h; nfs_fs.h doesn't need it at all. Several places in the tree needed direct include. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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96930a6365c99c160138a395566e360b27348b8f |
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26-Jul-2008 |
Adrian Bunk <bunk@kernel.org> |
make cgroup_seqfile_release() static cgroup_seqfile_release() can become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e885dcde75685e09f23cffae1f6d5169c105b8a0 |
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25-Jul-2008 |
Serge E. Hallyn <serue@us.ibm.com> |
cgroup_clone: use pid of newly created task for new cgroup cgroup_clone creates a new cgroup with the pid of the task. This works correctly for unshare, but for clone cgroup_clone is called from copy_namespaces inside copy_process, which happens before the new pid is created. As a result, the new cgroup was created with current's pid. This patch: 1. Moves the call inside copy_process to after the new pid is created 2. Passes the struct pid into ns_cgroup_clone (as it is not yet attached to the task) 3. Passes a name from ns_cgroup_clone() into cgroup_clone() so as to keep cgroup_clone() itself simpler 4. Uses pid_vnr() to get the process id value, so that the pid used to name the new cgroup is always the pid as it would be known to the task which did the cloning or unsharing. I think that is the most intuitive thing to do. This way, task t1 does clone(CLONE_NEWPID) to get t2, which does clone(CLONE_NEWPID) to get t3, then the cgroup for t3 will be named for the pid by which t2 knows t3. (Thanks to Dan Smith for finding the main bug) Changelog: June 11: Incorporate Paul Menage's feedback: don't pass NULL to ns_cgroup_clone from unshare, and reduce patch size by using 'nodename' in cgroup_clone. June 10: Original version [akpm@linux-foundation.org: build fix] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Serge Hallyn <serge@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Tested-by: Dan Smith <danms@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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af351026aafc8da16518a02b41c66d3e0c1cdef4 |
|
25-Jul-2008 |
Paul Menage <menage@google.com> |
cgroup files: turn attach_task_by_pid directly into a cgroup write handler This patch changes attach_task_by_pid() to take a u64 rather than a string; as a result it can be called directly as a control groups write_u64 handler, and cgroup_common_file_write() can be removed. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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6379c106152388f7ea45d6dda63edda0e9181fc8 |
|
25-Jul-2008 |
Paul Menage <menage@google.com> |
cgroup files: move notify_on_release file to separate write handler This patch moves the write handler for the cgroups notify_on_release file into a separate handler. This handler requires no cgroups locking since it relies on atomic bitops for synchronization. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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84eea842886ac35020be6043e04748ed22014359 |
|
25-Jul-2008 |
Paul Menage <menage@google.com> |
cgroups: misc cleanups to write_string patchset This patch contains cleanups suggested by reviewers for the recent write_string() patchset: - pair cgroup_lock_live_group() with cgroup_unlock() in cgroup.c for clarity, rather than directly unlocking cgroup_mutex. - make the return type of cgroup_lock_live_group() a bool - use a #define'd constant for the local buffer size in read/write functions Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e788e066c651b1bbf4a927dc95395c1aa13be436 |
|
25-Jul-2008 |
Paul Menage <menage@google.com> |
cgroup files: move the release_agent file to use typed handlers Adds cgroup_release_agent_write() and cgroup_release_agent_show() methods to handle writing/reading the path to a cgroup hierarchy's release agent. As a result, cgroup_common_file_read() is now unnecessary. As part of the change, a previously-tolerated race in cgroup_release_agent() is avoided by copying the current release_agent_path prior to calling call_usermode_helper(). Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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db3b14978abc02041046ed8353f0899cb58ffffc |
|
25-Jul-2008 |
Paul Menage <menage@google.com> |
cgroup files: add write_string cgroup control file method This patch adds a write_string() method for cgroups control files. The semantics are that a buffer is copied from userspace to kernelspace and the handler function invoked on that buffer. The buffer is guaranteed to be nul-terminated, and no longer than max_write_len (defaulting to 64 bytes if unspecified). Later patches will convert existing raw file write handlers in control group subsystems to use this method. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Acked-by: Balbir Singh <balbir@in.ibm.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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8947f9d5b361ce927be6d5c11fed57905b7a4100 |
|
25-Jul-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: annotate two variables with __read_mostly - need_forkexit_callback will be read only after system boot. - use_task_css_set_links will be read only after it's set. And these 2 variables are checked when a new process is forked. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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71cbb949d17d4d776abd547135feb7f3282405c8 |
|
25-Jul-2008 |
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> |
cgroup: list_for_each cleanup -------------------------- while() { list_entry(); ... } -------------------------- is equivalent to following code. -------------------------- list_for_each_entry(){ ... } -------------------------- later can review easily more. this patch is just clean up. it doesn't have any behavor change. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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7e9abd89cbdf9b73d327d8173343abce9022609b |
|
25-Jul-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: use read lock to guard find_existing_css_set() The function does not modify anything (except the temporary css template), so it's sufficient to hold read lock. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5c02b575780d0d785815a1e7b79a98edddee895a |
|
23-May-2008 |
Cedric Le Goater <clg@fr.ibm.com> |
cgroups: remove node_ prefix_from ns subsystem This is a slight change in the namespace cgroup subsystem api. The change is that previously when cgroup_clone() was called (currently only from the unshare path in ns_proxy cgroup, you'd get a new group named "node_$pid" whereas now you'll get a group named after just your pid.) The only users who would notice it are those who are using the ns_proxy cgroup subsystem to auto-create cgroups when namespaces are unshared - something of an experimental feature, which I think really needs more complete container/namespace support in order to be useful. I suspect the only users are Cedric and Serge, or maybe a few others on containers@lists.linux-foundation.org. And in fact it would only be noticed by the users who make the assumption about how the name is generated, rather than getting it from the /proc/<pid>/cgroups file for the process in question. Whether the change is actually needed or not I'm fairly agnostic on, but I guess it is more elegant to just use the pid as the new group name rather than adding a fairly arbitrary "node_" prefix on the front. [menage@google.com: provided changelog] Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Cc: "Paul Menage" <menage@google.com> Cc: "Serge E. Hallyn" <serue@us.ibm.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e4ad08fe64afca4ef79ecc4c624e6e871688da0d |
|
30-Apr-2008 |
Miklos Szeredi <mszeredi@suse.cz> |
mm: bdi: add separate writeback accounting capability Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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cf475ad28ac35cc9ba612d67158f29b73b38b05d |
|
29-Apr-2008 |
Balbir Singh <balbir@linux.vnet.ibm.com> |
cgroups: add an owner to the mm_struct Remove the mem_cgroup member from mm_struct and instead adds an owner. This approach was suggested by Paul Menage. The advantage of this approach is that, once the mm->owner is known, using the subsystem id, the cgroup can be determined. It also allows several control groups that are virtually grouped by mm_struct, to exist independent of the memory controller i.e., without adding mem_cgroup's for each controller, to mm_struct. A new config option CONFIG_MM_OWNER is added and the memory resource controller selects this config option. This patch also adds cgroup callbacks to notify subsystems when mm->owner changes. The mm_cgroup_changed callback is called with the task_lock() of the new task held and is called just prior to changing the mm->owner. I am indebted to Paul Menage for the several reviews of this patchset and helping me make it lighter and simpler. This patch was tested on a powerpc box, it was compiled with both the MM_OWNER config turned on and off. After the thread group leader exits, it's moved to init_css_state by cgroup_exit(), thus all future charges from runnings threads would be redirected to the init_css_set's subsystem. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: Hirokazu Takahashi <taka@valinux.co.jp> Cc: David Rientjes <rientjes@google.com>, Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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29486df325e1fe6e1764afcb19e3370804c2b002 |
|
29-Apr-2008 |
Serge E. Hallyn <serue@us.ibm.com> |
cgroups: introduce cft->read_seq() Introduce a read_seq() helper in cftype, which uses seq_file to print out lists. Use it in the devices cgroup. Also split devices.allow into two files, so now devices.deny and devices.allow are the ones to use to manipulate the whitelist, while devices.list outputs the cgroup's current whitelist. Signed-off-by: Serge E. Hallyn <serue@us.ibm.com> Acked-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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28fd5dfc12bde391981dfdcf20755952b6e916af |
|
29-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: remove the css_set linked-list Now we can run through the hash table instead of running through the linked-list. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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e8d55fdeb882cfcb5e8db5a5ce16edfba78aafc5 |
|
29-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: simplify init_subsys() We are at system boot and there is only 1 cgroup group (i,e, init_css_set), so we don't need to run through the css_set linked list. Neither do we need to run through the task list, since no processes have been created yet. Also referring to a comment in cgroup.h: struct css_set { ... /* * Set of subsystem states, one for each subsystem. This array * is immutable after creation apart from the init_css_set * during subsystem registration (at boot time). */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; } Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
472b1053f3c319cc60bfb2a0bb062fed77a93eb6 |
|
29-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroups: use a hash table for css_set finding When we attach a process to a different cgroup, the css_set linked-list will be run through to find a suitable existing css_set to use. This patch implements a hash table for better performance. The following benchmarks have been tested: For N in 1, 5, 10, 50, 100, 500, 1000, create N cgroups with one sleeping task in each, and then move an additional task through each cgroup in turn. Here is a test result: N Loop orig - Time(s) hash - Time(s) ---------------------------------------------- 1 10000 1.201231728 1.196311177 5 2000 1.065743872 1.040566424 10 1000 0.991054735 0.986876440 50 200 0.976554203 0.969608733 100 100 0.998504680 0.969218270 500 20 1.157347764 0.962602963 1000 10 1.619521852 1.085140172 Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d447ea2f30ec60370ddb99a668e5ac12995f043d |
|
29-Apr-2008 |
Pavel Emelyanov <xemul@openvz.org> |
cgroups: add the trigger callback to struct cftype Trigger callback can be used to receive a kick-up from the user space. The string written is ignored. The cftype->private is used for multiplexing events. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Acked-by: Paul Menage <menage@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
46ae220bea40bd1cf4abec2d5cdfb4f9396c7115 |
|
29-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: switch to proc_create() There is a race between create_proc_entry() and the assignment of file ops. proc_create() is invented to fix it. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
06a119204d3e1e67d393e996ed987b0df7998381 |
|
29-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: annotate cgroup_init_subsys with __init It is called by cgroup_init() and cgroup_init_early() only, which are annotated with __init. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e73d2c61d1fcbd3621688ae457b49509c8d4c601 |
|
29-Apr-2008 |
Paul Menage <menage@google.com> |
CGroups _s64 files: add cgroups read_s64/write_s64 file methods These patches add cgroups read_s64 and write_s64 control file methods (the signed equivalent of read_u64/write_u64) and use them to implement the cpu.rt_runtime_us control file in the CFS cgroup subsystem. This patch: These are the signed equivalents of the read_u64/write_u64 methods Signed-off-by: Paul Menage <menage@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
3116f0e3df0a67ad56f15dd4c5f6cefb04bb4a98 |
|
29-Apr-2008 |
Paul Menage <menage@google.com> |
CGroup API files: move "releasable" to cgroup_debug subsystem The "releasable" control file provided by the cgroup framework exports the state of a per-cgroup flag that's related to the notify-on-release feature. This isn't really generally useful, unless you're trying to debug this particular feature of cgroups. This patch moves the "releasable" file to the cgroup_debug subsystem. Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
9179656961adcea3c25403365597e486d851ac5e |
|
29-Apr-2008 |
Paul Menage <menage@google.com> |
CGroup API files: add cgroup map data type Adds a new type of supported control file representation, a map from strings to u64 values. Each map entry is printed as a line in a similar format to /proc/vmstat, i.e. "$key $value\n" Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
b7269dfc826fbf554c9e6a9eaa4e6ff95fa08656 |
|
29-Apr-2008 |
Paul Menage <menage@google.com> |
CGroup API files: strip all trailing whitespace in cgroup_write_u64 This removes the need for people to remember to pass the -n flag to echo when writing values to cgroup control files. Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
f4c753b7eacc277e506066abdda351cbc1cf8e6a |
|
29-Apr-2008 |
Paul Menage <menage@google.com> |
CGroup API files: rename read/write_uint methods to read_write_u64 Several people have justifiably complained that the "_uint" suffix is inappropriate for functions that handle u64 values, so this patch just renames all these functions and their users to have the suffic _u64. [peterz@infradead.org: build fix] Signed-off-by: Paul Menage <menage@google.com> Cc: "Li Zefan" <lizf@cn.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
4fe91d518e4958af7edebbeb112a3272b2be232d |
|
29-Apr-2008 |
Paul Jackson <pj@sgi.com> |
cgroup: fix sparse warning of shadow symbol in cgroup.c Fix a code warning: symbol 'p' shadows an earlier one This is a reincarnation of Harvey Harrison's patch: cpuset: sparse warnings in cpuset.c Independently, Cliff Wickman moved the affected code, from kernel/cpuset.c to kernel/cgroup.c, in his patch: cpusets: update_cpumask revision Signed-off-by: Paul Jackson <pj@sgi.com> Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Cliff Wickman <cpw@sgi.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
3df91fe30a1547af7e794c6e8cca76f4932c6ad7 |
|
29-Apr-2008 |
Adrian Bunk <bunk@kernel.org> |
make cgroup_enable_task_cg_lists() static Make the needlessly global cgroup_enable_task_cg_lists() static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
0e04388f0189fa1f6812a8e1cb6172136eada87e |
|
17-Apr-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix a race condition in manipulating tsk->cg_list When I ran a test program to fork mass processes and at the same time 'cat /cgroup/tasks', I got the following oops: ------------[ cut here ]------------ kernel BUG at lib/list_debug.c:72! invalid opcode: 0000 [#1] SMP Pid: 4178, comm: a.out Not tainted (2.6.25-rc9 #72) ... Call Trace: [<c044a5f9>] ? cgroup_exit+0x55/0x94 [<c0427acf>] ? do_exit+0x217/0x5ba [<c0427ed7>] ? do_group_exit+0.65/0x7c [<c0427efd>] ? sys_exit_group+0xf/0x11 [<c0404842>] ? syscall_call+0x7/0xb [<c05e0000>] ? init_cyrix+0x2fa/0x479 ... EIP: [<c04df671>] list_del+0x35/0x53 SS:ESP 0068:ebc7df4 ---[ end trace caffb7332252612b ]--- Fixing recursive fault but reboot is needed! After digging into the code and debugging, I finlly found out a race situation: do_exit() ->cgroup_exit() ->if (!list_empty(&tsk->cg_list)) list_del(&tsk->cg_list); cgroup_iter_start() ->cgroup_enable_task_cg_list() ->list_add(&tsk->cg_list, ..); In this case the list won't be deleted though the process has exited. We got two bug reports in the past, which seem to be the same bug as this one: http://lkml.org/lkml/2008/3/5/332 http://lkml.org/lkml/2007/10/17/224 Actually sometimes I got oops on list_del, sometimes oops on list_add. And I can change my test program a bit to trigger other oops. The patch has been tested both on x86_32 and x86_64. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
b6c3006d204a0b86e1ebe02ca38f9f071a03c7ef |
|
11-Apr-2008 |
Paul Menage <menage@google.com> |
cgroups: include hierarchy ids in /proc/<pid>/cgroup Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on each line. Currently this ID isn't really needed since a hierarchy can be completely identified by the set of subsystems bound to it, but this is likely to change in the near future in order to support stateless subsystems and merging/rebinding of subsystems. Getting this change into 2.6.25 reduces the need for an API change later. Signed-off-by: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
8bab8dded67d026c39367bbd5e27d2f6c556c38e |
|
04-Apr-2008 |
Paul Menage <menage@google.com> |
cgroups: add cgroup support for enabling controllers at boot time The effects of cgroup_disable=foo are: - foo isn't auto-mounted if you mount all cgroups in a single hierarchy - foo isn't visible as an individually mountable subsystem As a result there will only ever be one call to foo->create(), at init time; all processes will stay in this group, and the group will never be mounted on a visible hierarchy. Any additional effects (e.g. not allocating metadata) are up to the foo subsystem. This doesn't handle early_init subsystems (their "disabled" bit isn't set be, but it could easily be extended to do so if any of the early_init systems wanted it - I think it would just involve some nastier parameter processing since it would occur before the command-line argument parser had been run. Hugh said: Ballpark figures, I'm trying to get this question out rather than processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead to the affected paths, booting with cgroup_disable=memory cuts that back to 1% overhead (due to slightly bigger struct page). I'm no expert on distros, they may have no interest whatever in CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or without it, or apply the cgroup_disable=memory patches. Unix bench's execl test result on x86_64 was == just after boot without mounting any cgroup fs.== mem_cgorup=off : Execl Throughput 43.0 3150.1 732.6 mem_cgroup=on : Execl Throughput 43.0 2932.6 682.0 == [lizf@cn.fujitsu.com: fix boot option parsing] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com> Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
9dce07f1a441b77a15631cf0ed0238e0baa7ed64 |
|
29-Mar-2008 |
Al Viro <viro@ftp.linux.org.uk> |
NULL noise: fs/*, mm/*, kernel/* Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
b6abdb0e6ca5c2c0a7caa4131da2af0750927e72 |
|
04-Mar-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix default notify_on_release setting The documentation says the default value of notify_on_release of a child cgroup is inherited from its parent, which is reasonable, but the implementation just sets the flag disabled. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
bc231d2a048010d5e0b49ac7fddbfa822fc41109 |
|
24-Feb-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: remove dead code in cgroup_get_rootdir() Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
68db38f1537a44097e264f28bda751d6b919cd53 |
|
24-Feb-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: remove duplicate code in find_css_set() The list head res->tasks gets initialized twice in find_css_set(). Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
8d53d55d27754508e58e9ac18a4a445b110434bf |
|
24-Feb-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix subsys bitops Cgroup uses unsigned long for subsys bitops, not unsigned long long. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
f777073848ba3708d68d87e43f104f83316187d7 |
|
24-Feb-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix memory leak in cgroup_get_sb() opts.release_agent is not kfree()ed in all necessary places. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
a043e3b2c63445512c5592cbe3c8694f3c655e81 |
|
24-Feb-2008 |
Li Zefan <lizf@cn.fujitsu.com> |
cgroup: fix comments fix: - comments about need_forkexit_callback - comments about release agent - typo and comment style, etc. Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
73507f335f406ff31ceb97b39fa76eaee00f4f26 |
|
07-Feb-2008 |
Pavel Emelyanov <xemul@openvz.org> |
Handle pid namespaces in cgroups code There's one place that works with task pids - its the "tasks" file in cgroups. The read/write handlers assume, that the pid values go to/come from the user space and thus it is a virtual pid, i.e. the pid as it is seen from inside a namespace. Tune the code accordingly. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
956db3ca0606e78456786ef19fd4dc7a5151a6e1 |
|
07-Feb-2008 |
Cliff Wickman <cpw@sgi.com> |
hotplug cpu: move tasks in empty cpusets to parent This patch corrects a situation that occurs when one disables all the cpus in a cpuset. Currently, the disabled (cpu-less) cpuset inherits the cpus of its parent, which is incorrect because it may then overlap its cpu-exclusive sibling. Tasks of an empty cpuset should be moved to the cpuset which is the parent of their current cpuset. Or if the parent cpuset has no cpus, to its parent, etc. And the empty cpuset should be released (if it is flagged notify_on_release). Depends on the cgroup_scan_tasks() function (proposed by David Rientjes) to iterate through all tasks in the cpu-less cpuset. We are deliberately avoiding a walk of the tasklist. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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31a7df01fd0cd786f60873a921aecafac148c290 |
|
07-Feb-2008 |
Cliff Wickman <cpw@sgi.com> |
cgroups: mechanism to process each task in a cgroup Provide cgroup_scan_tasks(), which iterates through every task in a cgroup, calling a test function and a process function for each. And call the process function without holding the css_set_lock lock. The idea is David Rientjes', predicting that such a function will make it much easier in the future to extend things that require access to each task in a cgroup without holding the lock, [akpm@linux-foundation.org: cleanup] [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Cliff Wickman <cpw@sgi.com> Cc: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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4fca88c87b7969c698912e2de9b1b31088c777cb |
|
07-Feb-2008 |
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> |
memory cgroup enhancements: add- pre_destroy() handler Add a handler "pre_destroy" to cgroup_subsys. It is called before cgroup_rmdir() checks all subsys's refcnt. I think this is useful for subsys which have some extra refs even if there are no tasks in cgroup. By adding pre_destroy(), the kernel keeps the rule "destroy() against subsystem is called only when refcnt=0." and allows css ref to be used by other objects than tasks. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Kirill Korotaev <dev@sw.ru> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Paul Menage <menage@google.com> Cc: Pavel Emelianov <xemul@openvz.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e9685a03c8c3162cfa9ff02d254ea5c848f9facb |
|
07-Feb-2008 |
Adrian Bunk <bunk@kernel.org> |
kernel/cgroup.c: make 2 functions static cgroup_is_releasable() and notify_on_release() should be static, not global inline. Signed-off-by: Adrian Bunk <bunk@kernel.org> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
8dc4f3e17dd5f7e59ce568155ccd8974af879315 |
|
07-Feb-2008 |
Paul Menage <menage@google.com> |
cgroups: move cgroups destroy() callbacks to cgroup_diput() Move the calls to the cgroup subsystem destroy() methods from cgroup_rmdir() to cgroup_diput(). This allows control file reads and writes to access their subsystem state without having to be concerned with locking against cgroup destruction - the control file dentry will keep the cgroup and its subsystem state objects alive until the file is closed. The documentation is updated to reflect the changed semantics of destroy(); additionally the locking comments for destroy() and some other methods were clarified and decrustified. Signed-off-by: Paul Menage <menage@google.com> Cc: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
622d42cac9ed42098aa50c53994f625abfa3d473 |
|
07-Feb-2008 |
Paul Jackson <pj@sgi.com> |
cgroup simplify space stripping Simplify the space stripping code in cgroup file write. [akpm@linux-foundation.org: s/BUG_ON/BUILD_BUG_ON/] Signed-off-by: Paul Jackson <pj@sgi.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
e18f6318e5dab189efd4cb0bbfcbd923cc373e3c |
|
07-Feb-2008 |
Paul Jackson <pj@sgi.com> |
cgroup brace coding style fix Coding style fix - one line conditionals don't get braces. Signed-off-by: Paul Jackson <pj@sgi.com> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
3cdeed2986b09fcc77b4812ca10dbc057e4e5f8c |
|
07-Feb-2008 |
Adrian Bunk <bunk@kernel.org> |
kernel/cgroup.c: remove dead code This patch removes dead code spotted by the Coverity checker (look at the "(nbytes >= PATH_MAX)" check). Signed-off-by: Adrian Bunk <bunk@kernel.org> Cc: Paul Jackson <pj@sgi.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
cfe36bde59bc1ae868e775ad82386c3acaabb738 |
|
15-Nov-2007 |
Diego Calleja <diegocg@gmail.com> |
Improve cgroup printks When I boot with the 'quiet' parameter, I see on the screen: [ 0.000000] Initializing cgroup subsys cpuset [ 0.000000] Initializing cgroup subsys cpu [ 39.036026] Initializing cgroup subsys cpuacct [ 39.036080] Initializing cgroup subsys debug [ 39.036118] Initializing cgroup subsys ns This patch lowers the priority of those messages, adds a "cgroup: " prefix to another couple of printks and kills the useless reference to the source file. Signed-off-by: Diego Calleja <diegocg@gmail.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
3bdf590eac36ac5930deb9552febee3ff18cd2d1 |
|
24-Oct-2007 |
Jeff Garzik <jeff@garzik.org> |
cgroup: kill unused variable Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
|
bd89aabc6761de1c35b154fe6f914a445d301510 |
|
19-Oct-2007 |
Paul Menage <menage@google.com> |
Control groups: Replace "cont" with "cgrp" and other misc renaming Replace "cont" with "cgrp" and other misc renaming This patch finishes some of the names that got missed in the great "task containers" -> "control groups" rename. Primarily it renames the local variable "cont" to "cgrp" in a number of places, and renames the CONT_* enum members to CGRP_*. This patch is not intended to have any effect on the generated code; the output of "objdump -d kernel/cgroup.o" is unchanged. Signed-off-by: Paul Menage <menage@google.com> Acked-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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69cccb887a35f3761b7ea62cdd2bee602868c735 |
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19-Oct-2007 |
Pavel Emelyanov <xemul@openvz.org> |
Use task_pid_nr() instead of pid_nr(task_pid()) There are two places that do so - the cgroups subsystem and the autofs code. Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Ian Kent <raven@themaw.net> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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846c7bb055747989891f5cd2bb6e8d56243ba1e7 |
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19-Oct-2007 |
Balbir Singh <balbir@linux.vnet.ibm.com> |
Add cgroupstats This patch is inspired by the discussion at http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics as suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263. The patch is on top of 2.6.21-mm1 with Paul's cgroups v9 patches (forward ported) This patch implements per cgroup statistics infrastructure and re-uses code from the taskstats interface. A new set of cgroup operations are registered with commands and attributes. It should be very easy to *extend* per cgroup statistics, by adding members to the cgroupstats structure. The current model for cgroupstats is a pull, a push model (to post statistics on interesting events), should be very easy to add. Currently user space requests for statistics by passing the cgroup file descriptor. Statistics about the state of all the tasks in the cgroup is returned to user space. TODO's/NOTE: This patch provides an infrastructure for implementing cgroup statistics. Based on the needs of each controller, we can incrementally add more statistics, event based support for notification of statistics, accumulation of taskstats into cgroup statistics in the future. Sample output # ./cgroupstats -C /cgroup/a sleeping 2, blocked 0, running 1, stopped 0, uninterruptible 0 # ./cgroupstats -C /cgroup/ sleeping 154, blocked 0, running 0, stopped 0, uninterruptible 0 If the approach looks good, I'll enhance and post the user space utility for the same Feedback, comments, test results are always welcome! [akpm@linux-foundation.org: build fix] Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Paul Menage <menage@google.com> Cc: Jay Lan <jlan@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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81a6a5cdd2c5cd70874b88afe524ab09e9e869af |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: automatic userspace notification of idle cgroups Add the following files to the cgroup filesystem: notify_on_release - configures/reports whether the cgroup subsystem should attempt to run a release script when this cgroup becomes unused release_agent - configures/reports the release agent to be used for this hierarchy (top level in each hierarchy only) releasable - reports whether this cgroup would have been auto-released if notify_on_release was true and a release agent was configured (mainly useful for debugging) To avoid locking issues, invoking the userspace release agent is done via a workqueue task; cgroups that need to have their release agents invoked by the workqueue task are linked on to a list. [pj@sgi.com: Need to include kmod.h] Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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817929ec274bcfe771586d338bb31d1659615686 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: shared cgroup subsystem group arrays Replace the struct css_set embedded in task_struct with a pointer; all tasks that have the same set of memberships across all hierarchies will share a css_set object, and will be linked via their css_sets field to the "tasks" list_head in the css_set. Assuming that many tasks share the same cgroup assignments, this reduces overall space usage and keeps the size of the task_struct down (three pointers added to task_struct compared to a non-cgroups kernel, no matter how many subsystems are registered). [akpm@linux-foundation.org: fix a printk] [akpm@linux-foundation.org: build fix] Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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a424316ca154317367c7ddf89997d1c80e4a8051 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: add procfs interface Add: /proc/cgroups - general system info /proc/*/cgroup - per-task cgroup membership info [a.p.zijlstra@chello.nl: cgroups: bdi init hooks] Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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697f41610863c9264a7ae26dac9a387c9dda8c84 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: add cgroup_clone() interface Add support for cgroup_clone(), a way to create new cgroups intended to be used for systems such as namespace unsharing. A new subsystem callback, post_clone(), is added to allow subsystems to automatically configure cloned cgroups. Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b4f48b6363c81ca743ef46943ef23fd72e60f679 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: add fork()/exit() hooks This adds the necessary hooks to the fork() and exit() paths to ensure that new children inherit their parent's cgroup assignments, and that exiting processes release reference counts on their cgroups. Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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355e0c48b757b7fcc79ccb98fda8105ed37a1598 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Add cgroup write_uint() helper method Add write_uint() helper method for cgroup subsystems This helper is analagous to the read_uint() helper method for reporting u64 values to userspace. It's designed to reduce the amount of boilerplate requierd for creating new cgroup subsystems. Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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bbcb81d09104f0d440974b994c1fc508ccbe9503 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: add tasks file interface Add the per-directory "tasks" file for cgroupfs mounts; this allows the user to determine which tasks are members of a cgroup by reading a cgroup's "tasks", and to move a task into a cgroup by writing its pid to its "tasks". Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ddbcc7e8e50aefe467c01cac3dec71f118cd8ac2 |
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19-Oct-2007 |
Paul Menage <menage@google.com> |
Task Control Groups: basic task cgroup framework Generic Process Control Groups -------------------------- There have recently been various proposals floating around for resource management/accounting and other task grouping subsystems in the kernel, including ResGroups, User BeanCounters, NSProxy cgroups, and others. These all need the basic abstraction of being able to group together multiple processes in an aggregate, in order to track/limit the resources permitted to those processes, or control other behaviour of the processes, and all implement this grouping in different ways. This patchset provides a framework for tracking and grouping processes into arbitrary "cgroups" and assigning arbitrary state to those groupings, in order to control the behaviour of the cgroup as an aggregate. The intention is that the various resource management and virtualization/cgroup efforts can also become task cgroup clients, with the result that: - the userspace APIs are (somewhat) normalised - it's easier to test e.g. the ResGroups CPU controller in conjunction with the BeanCounters memory controller, or use either of them as the resource-control portion of a virtual server system. - the additional kernel footprint of any of the competing resource management systems is substantially reduced, since it doesn't need to provide process grouping/containment, hence improving their chances of getting into the kernel This patch: Add the main task cgroups framework - the cgroup filesystem, and the basic structures for tracking membership and associating subsystem state objects to tasks. Signed-off-by: Paul Menage <menage@google.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Dave Hansen <haveblue@us.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Paul Jackson <pj@sgi.com> Cc: Kirill Korotaev <dev@openvz.org> Cc: Herbert Poetzl <herbert@13thfloor.at> Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com> Cc: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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