| f4da80727cfbc3590d95ff17ef8db96e6f1483a4 |
|
08-Sep-2014 |
Tejun Heo <tj@kernel.org> |
blkcg: remove blkcg->id
blkcg->id is a unique id given to each blkcg; however, the
cgroup_subsys_state which each blkcg embeds already has ->serial_nr
which can be used for the same purpose. Drop blkcg->id and replace
its uses with blkcg->css.serial_nr. Rename cfq_cgroup->blkcg_id to
->blkcg_serial_nr and @id in check_blkcg_changed() to @serial_nr for
consistency.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| 2a1b4cf2331d92bc009bf94fa02a24604cdaf24c |
|
06-Jul-2014 |
Tejun Heo <tj@kernel.org> |
blkcg: don't call into policy draining if root_blkg is already gone
While a queue is being destroyed, all the blkgs are destroyed and its
->root_blkg pointer is set to NULL. If someone else starts to drain
while the queue is in this state, the following oops happens.
NULL pointer dereference at 0000000000000028
IP: [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
PGD e4a1067 PUD b773067 PMD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: cfq_iosched(-) [last unloaded: cfq_iosched]
CPU: 1 PID: 537 Comm: bash Not tainted 3.16.0-rc3-work+ #2
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff88000e222250 ti: ffff88000efd4000 task.ti: ffff88000efd4000
RIP: 0010:[<ffffffff8144e944>] [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
RSP: 0018:ffff88000efd7bf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff880015091450 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88000efd7c10 R08: 0000000000000000 R09: 0000000000000001
R10: ffff88000e222250 R11: 0000000000000000 R12: ffff880015091450
R13: ffff880015092e00 R14: ffff880015091d70 R15: ffff88001508fc28
FS: 00007f1332650740(0000) GS:ffff88001fa80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000028 CR3: 0000000009446000 CR4: 00000000000006e0
Stack:
ffffffff8144e8f6 ffff880015091450 0000000000000000 ffff880015091d80
ffff88000efd7c28 ffffffff8144ae2f ffff880015091450 ffff88000efd7c58
ffffffff81427641 ffff880015091450 ffffffff82401f00 ffff880015091450
Call Trace:
[<ffffffff8144ae2f>] blkcg_drain_queue+0x1f/0x60
[<ffffffff81427641>] __blk_drain_queue+0x71/0x180
[<ffffffff81429b3e>] blk_queue_bypass_start+0x6e/0xb0
[<ffffffff814498b8>] blkcg_deactivate_policy+0x38/0x120
[<ffffffff8144ec44>] blk_throtl_exit+0x34/0x50
[<ffffffff8144aea5>] blkcg_exit_queue+0x35/0x40
[<ffffffff8142d476>] blk_release_queue+0x26/0xd0
[<ffffffff81454968>] kobject_cleanup+0x38/0x70
[<ffffffff81454848>] kobject_put+0x28/0x60
[<ffffffff81427505>] blk_put_queue+0x15/0x20
[<ffffffff817d07bb>] scsi_device_dev_release_usercontext+0x16b/0x1c0
[<ffffffff810bc339>] execute_in_process_context+0x89/0xa0
[<ffffffff817d064c>] scsi_device_dev_release+0x1c/0x20
[<ffffffff817930e2>] device_release+0x32/0xa0
[<ffffffff81454968>] kobject_cleanup+0x38/0x70
[<ffffffff81454848>] kobject_put+0x28/0x60
[<ffffffff817934d7>] put_device+0x17/0x20
[<ffffffff817d11b9>] __scsi_remove_device+0xa9/0xe0
[<ffffffff817d121b>] scsi_remove_device+0x2b/0x40
[<ffffffff817d1257>] sdev_store_delete+0x27/0x30
[<ffffffff81792ca8>] dev_attr_store+0x18/0x30
[<ffffffff8126f75e>] sysfs_kf_write+0x3e/0x50
[<ffffffff8126ea87>] kernfs_fop_write+0xe7/0x170
[<ffffffff811f5e9f>] vfs_write+0xaf/0x1d0
[<ffffffff811f69bd>] SyS_write+0x4d/0xc0
[<ffffffff81d24692>] system_call_fastpath+0x16/0x1b
776687bce42b ("block, blk-mq: draining can't be skipped even if
bypass_depth was non-zero") made it easier to trigger this bug by
making blk_queue_bypass_start() drain even when it loses the first
bypass test to blk_cleanup_queue(); however, the bug has always been
there even before the commit as blk_queue_bypass_start() could race
against queue destruction, win the initial bypass test but perform the
actual draining after blk_cleanup_queue() already destroyed all blkgs.
Fix it by skippping calling into policy draining if all the blkgs are
already gone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Shirish Pargaonkar <spargaonkar@suse.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Jet Chen <jet.chen@intel.com>
Cc: stable@vger.kernel.org
Tested-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| 2cf669a58dc08fa065a8bd0dca866c0e6cb358cc |
|
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>
|
| 5577964e64692e17cc498854b7e0833e6532cd64 |
|
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>
|
| 0b462c89e31f7eb6789713437eb551833ee16ff3 |
|
06-Jul-2014 |
Tejun Heo <tj@kernel.org> |
blkcg: don't call into policy draining if root_blkg is already gone
While a queue is being destroyed, all the blkgs are destroyed and its
->root_blkg pointer is set to NULL. If someone else starts to drain
while the queue is in this state, the following oops happens.
NULL pointer dereference at 0000000000000028
IP: [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
PGD e4a1067 PUD b773067 PMD 0
Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: cfq_iosched(-) [last unloaded: cfq_iosched]
CPU: 1 PID: 537 Comm: bash Not tainted 3.16.0-rc3-work+ #2
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
task: ffff88000e222250 ti: ffff88000efd4000 task.ti: ffff88000efd4000
RIP: 0010:[<ffffffff8144e944>] [<ffffffff8144e944>] blk_throtl_drain+0x84/0x230
RSP: 0018:ffff88000efd7bf0 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffff880015091450 RCX: 0000000000000001
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88000efd7c10 R08: 0000000000000000 R09: 0000000000000001
R10: ffff88000e222250 R11: 0000000000000000 R12: ffff880015091450
R13: ffff880015092e00 R14: ffff880015091d70 R15: ffff88001508fc28
FS: 00007f1332650740(0000) GS:ffff88001fa80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000028 CR3: 0000000009446000 CR4: 00000000000006e0
Stack:
ffffffff8144e8f6 ffff880015091450 0000000000000000 ffff880015091d80
ffff88000efd7c28 ffffffff8144ae2f ffff880015091450 ffff88000efd7c58
ffffffff81427641 ffff880015091450 ffffffff82401f00 ffff880015091450
Call Trace:
[<ffffffff8144ae2f>] blkcg_drain_queue+0x1f/0x60
[<ffffffff81427641>] __blk_drain_queue+0x71/0x180
[<ffffffff81429b3e>] blk_queue_bypass_start+0x6e/0xb0
[<ffffffff814498b8>] blkcg_deactivate_policy+0x38/0x120
[<ffffffff8144ec44>] blk_throtl_exit+0x34/0x50
[<ffffffff8144aea5>] blkcg_exit_queue+0x35/0x40
[<ffffffff8142d476>] blk_release_queue+0x26/0xd0
[<ffffffff81454968>] kobject_cleanup+0x38/0x70
[<ffffffff81454848>] kobject_put+0x28/0x60
[<ffffffff81427505>] blk_put_queue+0x15/0x20
[<ffffffff817d07bb>] scsi_device_dev_release_usercontext+0x16b/0x1c0
[<ffffffff810bc339>] execute_in_process_context+0x89/0xa0
[<ffffffff817d064c>] scsi_device_dev_release+0x1c/0x20
[<ffffffff817930e2>] device_release+0x32/0xa0
[<ffffffff81454968>] kobject_cleanup+0x38/0x70
[<ffffffff81454848>] kobject_put+0x28/0x60
[<ffffffff817934d7>] put_device+0x17/0x20
[<ffffffff817d11b9>] __scsi_remove_device+0xa9/0xe0
[<ffffffff817d121b>] scsi_remove_device+0x2b/0x40
[<ffffffff817d1257>] sdev_store_delete+0x27/0x30
[<ffffffff81792ca8>] dev_attr_store+0x18/0x30
[<ffffffff8126f75e>] sysfs_kf_write+0x3e/0x50
[<ffffffff8126ea87>] kernfs_fop_write+0xe7/0x170
[<ffffffff811f5e9f>] vfs_write+0xaf/0x1d0
[<ffffffff811f69bd>] SyS_write+0x4d/0xc0
[<ffffffff81d24692>] system_call_fastpath+0x16/0x1b
776687bce42b ("block, blk-mq: draining can't be skipped even if
bypass_depth was non-zero") made it easier to trigger this bug by
making blk_queue_bypass_start() drain even when it loses the first
bypass test to blk_cleanup_queue(); however, the bug has always been
there even before the commit as blk_queue_bypass_start() could race
against queue destruction, win the initial bypass test but perform the
actual draining after blk_cleanup_queue() already destroyed all blkgs.
Fix it by skippping calling into policy draining if all the blkgs are
already gone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Shirish Pargaonkar <spargaonkar@suse.com>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Jet Chen <jet.chen@intel.com>
Cc: stable@vger.kernel.org
Tested-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| 1ced953b17bfaf54ec1499f8bbfdf31ab36453af |
|
09-Jul-2014 |
Tejun Heo <tj@kernel.org> |
blkcg, memcg: make blkcg depend on memcg on the default hierarchy
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.
cgroup now has a mechanism to express such dependency -
cgroup_subsys->depends_on. This patch declares that blkcg depends on
memcg so that memcg is enabled automatically on the default hierarchy
when available. Future changes will make blkcg map the memcg tag to
find out the cgroup to blame for writeback IOs.
As this means that a memcg may be made invisible, this patch also
implements css_reset() for memcg which resets its basic
configurations. This implementation will probably need to be expanded
to cover other states which are used in the default hierarchy.
v2: blkcg's dependency on memcg is wrapped with CONFIG_MEMCG to avoid
build failure. Reported by kbuild test robot.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
|
| d5bf02914ea3ecf28db4f830f136dc04146b2317 |
|
23-Jun-2014 |
Jens Axboe <axboe@fb.com> |
Revert "block: add __init to blkcg_policy_register"
This reverts commit a2d445d440003f2d70ee4cd4970ea82ace616fee.
The original commit is buggy, we do use the registration functions
at runtime for modular builds.
|
| a5049a8ae34950249a7ae94c385d7c5c98914412 |
|
19-Jun-2014 |
Tejun Heo <tj@kernel.org> |
blkcg: fix use-after-free in __blkg_release_rcu() by making blkcg_gq refcnt an atomic_t
Hello,
So, this patch should do. Joe, Vivek, can one of you guys please
verify that the oops goes away with this patch?
Jens, the original thread can be read at
http://thread.gmane.org/gmane.linux.kernel/1720729
The fix converts blkg->refcnt from int to atomic_t. It does some
overhead but it should be minute compared to everything else which is
going on and the involved cacheline bouncing, so I think it's highly
unlikely to cause any noticeable difference. Also, the refcnt in
question should be converted to a perpcu_ref for blk-mq anyway, so the
atomic_t is likely to go away pretty soon anyway.
Thanks.
------- 8< -------
__blkg_release_rcu() may be invoked after the associated request_queue
is released with a RCU grace period inbetween. As such, the function
and callbacks invoked from it must not dereference the associated
request_queue. This is clearly indicated in the comment above the
function.
Unfortunately, while trying to fix a different issue, 2a4fd070ee85
("blkcg: move bulk of blkcg_gq release operations to the RCU
callback") ignored this and added [un]locking of @blkg->q->queue_lock
to __blkg_release_rcu(). This of course can cause oops as the
request_queue may be long gone by the time this code gets executed.
general protection fault: 0000 [#1] SMP
CPU: 21 PID: 30 Comm: rcuos/21 Not tainted 3.15.0 #1
Hardware name: Stratus ftServer 6400/G7LAZ, BIOS BIOS Version 6.3:57 12/25/2013
task: ffff880854021de0 ti: ffff88085403c000 task.ti: ffff88085403c000
RIP: 0010:[<ffffffff8162e9e5>] [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP: 0018:ffff88085403fdf0 EFLAGS: 00010086
RAX: 0000000000020000 RBX: 0000000000000010 RCX: 0000000000000000
RDX: 000060ef80008248 RSI: 0000000000000286 RDI: 6b6b6b6b6b6b6b6b
RBP: ffff88085403fdf0 R08: 0000000000000286 R09: 0000000000009f39
R10: 0000000000020001 R11: 0000000000020001 R12: ffff88103c17a130
R13: ffff88103c17a080 R14: 0000000000000000 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff88107fca0000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000006e5ab8 CR3: 000000000193d000 CR4: 00000000000407e0
Stack:
ffff88085403fe18 ffffffff812cbfc2 ffff88103c17a130 0000000000000000
ffff88103c17a130 ffff88085403fec0 ffffffff810d1d28 ffff880854021de0
ffff880854021de0 ffff88107fcaec58 ffff88085403fe80 ffff88107fcaec30
Call Trace:
[<ffffffff812cbfc2>] __blkg_release_rcu+0x72/0x150
[<ffffffff810d1d28>] rcu_nocb_kthread+0x1e8/0x300
[<ffffffff81091d81>] kthread+0xe1/0x100
[<ffffffff8163813c>] ret_from_fork+0x7c/0xb0
Code: ff 47 04 48 8b 7d 08 be 00 02 00 00 e8 55 48 a4 ff 5d c3 0f 1f 00 66 66 66 66 90 55 48 89 e5
+fa 66 66 90 66 66 90 b8 00 00 02 00 <f0> 0f c1 07 89 c2 c1 ea 10 66 39 c2 75 02 5d c3 83 e2 fe 0f
+b7
RIP [<ffffffff8162e9e5>] _raw_spin_lock_irq+0x15/0x60
RSP <ffff88085403fdf0>
The request_queue locking was added because blkcg_gq->refcnt is an int
protected with the queue lock and __blkg_release_rcu() needs to put
the parent. Let's fix it by making blkcg_gq->refcnt an atomic_t and
dropping queue locking in the function.
Given the general heavy weight of the current request_queue and blkcg
operations, this is unlikely to cause any noticeable overhead.
Moreover, blkcg_gq->refcnt is likely to be converted to percpu_ref in
the near future, so whatever (most likely negligible) overhead it may
add is temporary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Link: http://lkml.kernel.org/g/alpine.DEB.2.02.1406081816540.17948@jlaw-desktop.mno.stratus.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| a2d445d440003f2d70ee4cd4970ea82ace616fee |
|
10-Jun-2014 |
Fabian Frederick <fabf@skynet.be> |
block: add __init to blkcg_policy_register
blkcg_policy_register is only called by
__init functions:
__init cfq_init
__init throtl_init
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| ec903c0c858e4963a9e0724bdcadfa837253341c |
|
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>
|
| 36c38fb7144aa941dc072ba8f58b2dbe509c0345 |
|
05-May-2014 |
Tejun Heo <tj@kernel.org> |
blkcg: use trylock on blkcg_pol_mutex in blkcg_reset_stats()
During the recent conversion of cgroup to kernfs, cgroup_tree_mutex
which nests above both the kernfs s_active protection and cgroup_mutex
is added to synchronize cgroup file type operations as cgroup_mutex
needed to be grabbed from some file operations and thus can't be put
above s_active protection.
While this arrangement mostly worked for cgroup, this triggered the
following lockdep warning.
======================================================
[ INFO: possible circular locking dependency detected ]
3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429 Tainted: G W
-------------------------------------------------------
trinity-c173/9024 is trying to acquire lock:
(blkcg_pol_mutex){+.+.+.}, at: blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)
but task is already holding lock:
(s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283)
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (s_active#89){++++.+}:
lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
__kernfs_remove (arch/x86/include/asm/atomic.h:27 fs/kernfs/dir.c:352 fs/kernfs/dir.c:1024)
kernfs_remove_by_name_ns (fs/kernfs/dir.c:1219)
cgroup_addrm_files (include/linux/kernfs.h:427 kernel/cgroup.c:1074 kernel/cgroup.c:2899)
cgroup_clear_dir (kernel/cgroup.c:1092 (discriminator 2))
rebind_subsystems (kernel/cgroup.c:1144)
cgroup_setup_root (kernel/cgroup.c:1568)
cgroup_mount (kernel/cgroup.c:1716)
mount_fs (fs/super.c:1094)
vfs_kern_mount (fs/namespace.c:899)
do_mount (fs/namespace.c:2238 fs/namespace.c:2561)
SyS_mount (fs/namespace.c:2758 fs/namespace.c:2729)
tracesys (arch/x86/kernel/entry_64.S:746)
-> #1 (cgroup_tree_mutex){+.+.+.}:
lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
cgroup_add_cftypes (include/linux/list.h:76 kernel/cgroup.c:3040)
blkcg_policy_register (block/blk-cgroup.c:1106)
throtl_init (block/blk-throttle.c:1694)
do_one_initcall (init/main.c:789)
kernel_init_freeable (init/main.c:854 init/main.c:863 init/main.c:882 init/main.c:1003)
kernel_init (init/main.c:935)
ret_from_fork (arch/x86/kernel/entry_64.S:552)
-> #0 (blkcg_pol_mutex){+.+.+.}:
__lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)
cgroup_file_write (kernel/cgroup.c:2714)
kernfs_fop_write (fs/kernfs/file.c:295)
vfs_write (fs/read_write.c:532)
SyS_write (fs/read_write.c:584 fs/read_write.c:576)
tracesys (arch/x86/kernel/entry_64.S:746)
other info that might help us debug this:
Chain exists of:
blkcg_pol_mutex --> cgroup_tree_mutex --> s_active#89
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(s_active#89);
lock(cgroup_tree_mutex);
lock(s_active#89);
lock(blkcg_pol_mutex);
*** DEADLOCK ***
4 locks held by trinity-c173/9024:
#0: (&f->f_pos_lock){+.+.+.}, at: __fdget_pos (fs/file.c:714)
#1: (sb_writers#18){.+.+.+}, at: vfs_write (include/linux/fs.h:2255 fs/read_write.c:530)
#2: (&of->mutex){+.+.+.}, at: kernfs_fop_write (fs/kernfs/file.c:283)
#3: (s_active#89){++++.+}, at: kernfs_fop_write (fs/kernfs/file.c:283)
stack backtrace:
CPU: 3 PID: 9024 Comm: trinity-c173 Tainted: G W 3.15.0-rc3-next-20140430-sasha-00016-g4e281fa-dirty #429
ffffffff919687b0 ffff8805f6373bb8 ffffffff8e52cdbb 0000000000000002
ffffffff919d8400 ffff8805f6373c08 ffffffff8e51fb88 0000000000000004
ffff8805f6373c98 ffff8805f6373c08 ffff88061be70d98 ffff88061be70dd0
Call Trace:
dump_stack (lib/dump_stack.c:52)
print_circular_bug (kernel/locking/lockdep.c:1216)
__lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182)
lock_acquire (arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602)
mutex_lock_nested (kernel/locking/mutex.c:486 kernel/locking/mutex.c:587)
blkcg_reset_stats (include/linux/spinlock.h:328 block/blk-cgroup.c:455)
cgroup_file_write (kernel/cgroup.c:2714)
kernfs_fop_write (fs/kernfs/file.c:295)
vfs_write (fs/read_write.c:532)
SyS_write (fs/read_write.c:584 fs/read_write.c:576)
This is a highly unlikely but valid circular dependency between "echo
1 > blkcg.reset_stats" and cfq module [un]loading. cgroup is going
through further locking update which will remove this complication but
for now let's use trylock on blkcg_pol_mutex and retry the file
operation if the trylock fails.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Sasha Levin <sasha.levin@oracle.com>
References: http://lkml.kernel.org/g/5363C04B.4010400@oracle.com
|
| ec6c676a08b0779a32c9cec9fae7532add32fe15 |
|
17-Feb-2014 |
Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
block: Substitute rcu_access_pointer() for rcu_dereference_raw()
(Trivial patch.)
If the code is looking at the RCU-protected pointer itself, but not
dereferencing it, the rcu_dereference() functions can be downgraded to
rcu_access_pointer(). This commit makes this downgrade in blkg_destroy()
and ioc_destroy_icq(), both of which simply compare the RCU-protected
pointer against another pointer with no dereferencing.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <axboe@fb.com>
|
| 924f0d9a2078f49ff331bb43196ec5afadc16b8f |
|
13-Feb-2014 |
Tejun Heo <tj@kernel.org> |
cgroup: drop @skip_css from cgroup_taskset_for_each()
If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching
css. The intention of the interface is to make it easy to skip css's
(cgroup_subsys_states) which already match the migration target;
however, this is entirely unnecessary as migration taskset doesn't
include tasks which are already in the target cgroup. Drop @skip_css
from cgroup_taskset_for_each().
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>
|
| 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>
|
| 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>
|
| 577cee1e8db6b98b51506e956264b84553426e65 |
|
28-Aug-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: relocate root_blkg setting and clearing
Hello, Jens.
The original thread can be read from
http://thread.gmane.org/gmane.linux.kernel.cgroups/8937
While it leads to oops, given that it only triggers under specific
configurations which aren't common. I don't think it's necessary to
backport it through -stable and merging it during the coming merge
window should be enough.
Thanks!
----- 8< -----
Currently, q->root_blkg and q->root_rl.blkg are set from
blkcg_activate_policy() and cleared from blkg_destroy_all(). This
doesn't necessarily coincide with the lifetime of the root blkcg_gq
leading to the following oops when blkcg is enabled but no policy is
activated because __blk_queue_next_rl() malfunctions expecting the
root_blkg pointers to be set.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810c58cb>] __wake_up_common+0x2b/0x90
PGD 60f7a9067 PUD 60f4c9067 PMD 0
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
gsmi: Log Shutdown Reason 0x03
Modules linked in: act_mirred cls_tcindex cls_prioshift sch_dsmark xt_multiport iptable_mangle sata_mv elephant elephant_dev_num cdc_acm uhci_hcd ehci_hcd i2c_d
CPU: 9 PID: 41382 Comm: iSCSI-write- Not tainted 3.11.0-dbg-DEV #19
Hardware name: Intel XXX
task: ffff88060d16eec0 ti: ffff88060d170000 task.ti: ffff88060d170000
RIP: 0010:[<ffffffff810c58cb>] [<ffffffff810c58cb>] __wake_up_common+0x2b/0x90
RSP: 0000:ffff88060d171818 EFLAGS: 00010096
RAX: 0000000000000082 RBX: ffff880baa3dee60 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000003 RDI: ffff880baa3dee60
RBP: ffff88060d171858 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000002 R12: ffff880baa3dee98
R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000003
FS: 00007f977cba6700(0000) GS:ffff880c79c60000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 000000060f7a5000 CR4: 00000000000007e0
Stack:
0000000000000082 0000000000000000 ffff88060d171858 ffff880baa3dee60
0000000000000082 0000000000000003 0000000000000000 0000000000000000
ffff88060d171898 ffffffff810c7848 ffff88060d171888 ffff880bde4bc4b8
Call Trace:
[<ffffffff810c7848>] __wake_up+0x48/0x70
[<ffffffff8131da53>] __blk_drain_queue+0x123/0x190
[<ffffffff8131dbb5>] blk_cleanup_queue+0xf5/0x210
[<ffffffff8141877a>] __scsi_remove_device+0x5a/0xd0
[<ffffffff81418824>] scsi_remove_device+0x34/0x50
[<ffffffff814189cb>] scsi_remove_target+0x16b/0x220
[<ffffffff814210f1>] __iscsi_unbind_session+0xd1/0x1b0
[<ffffffff814212b2>] iscsi_remove_session+0xe2/0x1c0
[<ffffffff814213a6>] iscsi_destroy_session+0x16/0x60
[<ffffffff81423a59>] iscsi_session_teardown+0xd9/0x100
[<ffffffff8142b75a>] iscsi_sw_tcp_session_destroy+0x5a/0xb0
[<ffffffff81420948>] iscsi_if_rx+0x10e8/0x1560
[<ffffffff81573335>] netlink_unicast+0x145/0x200
[<ffffffff815736f3>] netlink_sendmsg+0x303/0x410
[<ffffffff81528196>] sock_sendmsg+0xa6/0xd0
[<ffffffff815294bc>] ___sys_sendmsg+0x38c/0x3a0
[<ffffffff811ea840>] ? fget_light+0x40/0x160
[<ffffffff811ea899>] ? fget_light+0x99/0x160
[<ffffffff811ea840>] ? fget_light+0x40/0x160
[<ffffffff8152bc79>] __sys_sendmsg+0x49/0x90
[<ffffffff8152bcd2>] SyS_sendmsg+0x12/0x20
[<ffffffff815fb642>] system_call_fastpath+0x16/0x1b
Code: 66 66 66 66 90 55 48 89 e5 41 57 41 89 f7 41 56 41 89 ce 41 55 41 54 4c 8d 67 38 53 48 83 ec 18 89 55 c4 48 8b 57 38 4c 89 45 c8 <4c> 8b 2a 48 8d 42 e8 49
Fix it by moving r->root_blkg and q->root_rl.blkg setting to
blkg_create() and clearing to blkg_destroy() so that they area
initialized when a root blkg is created and cleared when destroyed.
Reported-and-tested-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| bd8815a6d802fc16a7a106e170593aa05dc17e72 |
|
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>
|
| 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>
|
| 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>
|
| 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>
|
| 2bb566cb68dfafad328af666ebadf0e49accd6ca |
|
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>
|
| eb95419b023abacb415e2a18fea899023ce7624d |
|
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>
|
| 9138125beabbb76b4a373d4a619870f6f5d86fc5 |
|
14-May-2013 |
Tejun Heo <tj@kernel.org> |
blk-throttle: implement proper hierarchy support
With the recent updates, blk-throttle is finally ready for proper
hierarchy support. Dispatching now honors service_queue->parent_sq
and propagates correctly. The only thing missing is setting
->parent_sq correctly so that throtl_grp hierarchy matches the cgroup
hierarchy.
This patch updates throtl_pd_init() such that service_queues form the
same hierarchy as the cgroup hierarchy if sane_behavior is enabled.
As this concludes proper hierarchy support for blkcg, the shameful
.broken_hierarchy tag is removed from blkio_subsys.
v2: Updated blkio-controller.txt as suggested by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
|
| 2a4fd070ee8561d918a3776388331bb7e92ea59e |
|
14-May-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: move bulk of blkcg_gq release operations to the RCU callback
Currently, when the last reference of a blkcg_gq is put, all then
release operations sans the actual freeing happen directly in
blkg_put(). As blkg_put() may be called under queue_lock, all
pd_exit_fn()s may be too. This makes it impossible for pd_exit_fn()s
to use del_timer_sync() on timers which grab the queue_lock which is
an irq-safe lock due to the deadlock possibility described in the
comment on top of del_timer_sync().
This can be easily avoided by perfoming the release operations in the
RCU callback instead of directly from blkg_put(). This patch moves
the blkcg_gq release operations to the RCU callback.
As this leaves __blkg_release() with only call_rcu() invocation,
blkg_rcu_free() is renamed to __blkg_release_rcu(), exported and
call_rcu() invocation is now done directly from blkg_put() instead of
going through __blkg_release() which is removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| db61367038dcd222476881cb09fd54661b3cd508 |
|
14-May-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: invoke blkcg_policy->pd_init() after parent is linked
Currently, when creating a new blkcg_gq, each policy's pd_init_fn() is
invoked in blkg_alloc() before the parent is linked. This makes it
difficult for policies to perform initializations which are dependent
on the parent.
This patch moves pd_init_fn() invocations to blkg_create() after the
parent blkg is linked where the new blkg is fully initialized. As
this means that blkg_free() can't assume that pd's are initialized,
pd_exit_fn() invocations are moved to __blkg_release(). This
guarantees that pd_exit_fn() is also invoked with fully initialized
blkgs with valid parent pointers.
This will help implementing hierarchy support in blk-throttle.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| dd4a4ffc0a4723cd0bef065af549803d256e1f7e |
|
14-May-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: move blkg_for_each_descendant_pre() to block/blk-cgroup.h
blk-throttle hierarchy support will make use of it. Move
blkg_for_each_descendant_pre() from block/blk-cgroup.c to
block/blk-cgroup.h.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 2423c9c3f0ffffa8f87cbdafe9781273c5d1b6a2 |
|
14-May-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: fix error return path in blkg_create()
In blkg_create(), after lookup of parent fails, the control jumps to
error path with the error code encoded into @blkg. The error path
doesn't use @blkg for the return value. It returns ERR_PTR(ret).
Make lookup fail path set @ret instead of @blkg.
Note that the parent lookup is guaranteed to succeed at that point and
the condition check is purely for sanity and triggers WARN when fails.
As such, I don't think it's necessary to mark it for -stable.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| e5072664f8237cf53b0bd68a51aa1a7bc69061c5 |
|
09-Apr-2013 |
Jun'ichi Nomura <j-nomura@ce.jp.nec.com> |
blkcg: fix "scheduling while atomic" in blk_queue_bypass_start
Since 749fefe677 in v3.7 ("block: lift the initial queue bypass mode
on blk_register_queue() instead of blk_init_allocated_queue()"),
the following warning appears when multipath is used with CONFIG_PREEMPT=y.
This patch moves blk_queue_bypass_start() before radix_tree_preload()
to avoid the sleeping call while preemption is disabled.
BUG: scheduling while atomic: multipath/2460/0x00000002
1 lock held by multipath/2460:
#0: (&md->type_lock){......}, at: [<ffffffffa019fb05>] dm_lock_md_type+0x17/0x19 [dm_mod]
Modules linked in: ...
Pid: 2460, comm: multipath Tainted: G W 3.7.0-rc2 #1
Call Trace:
[<ffffffff810723ae>] __schedule_bug+0x6a/0x78
[<ffffffff81428ba2>] __schedule+0xb4/0x5e0
[<ffffffff814291e6>] schedule+0x64/0x66
[<ffffffff8142773a>] schedule_timeout+0x39/0xf8
[<ffffffff8108ad5f>] ? put_lock_stats+0xe/0x29
[<ffffffff8108ae30>] ? lock_release_holdtime+0xb6/0xbb
[<ffffffff814289e3>] wait_for_common+0x9d/0xee
[<ffffffff8107526c>] ? try_to_wake_up+0x206/0x206
[<ffffffff810c0eb8>] ? kfree_call_rcu+0x1c/0x1c
[<ffffffff81428aec>] wait_for_completion+0x1d/0x1f
[<ffffffff810611f9>] wait_rcu_gp+0x5d/0x7a
[<ffffffff81061216>] ? wait_rcu_gp+0x7a/0x7a
[<ffffffff8106fb18>] ? complete+0x21/0x53
[<ffffffff810c0556>] synchronize_rcu+0x1e/0x20
[<ffffffff811dd903>] blk_queue_bypass_start+0x5d/0x62
[<ffffffff811ee109>] blkcg_activate_policy+0x73/0x270
[<ffffffff81130521>] ? kmem_cache_alloc_node_trace+0xc7/0x108
[<ffffffff811f04b3>] cfq_init_queue+0x80/0x28e
[<ffffffffa01a1600>] ? dm_blk_ioctl+0xa7/0xa7 [dm_mod]
[<ffffffff811d8c41>] elevator_init+0xe1/0x115
[<ffffffff811e229f>] ? blk_queue_make_request+0x54/0x59
[<ffffffff811dd743>] blk_init_allocated_queue+0x8c/0x9e
[<ffffffffa019ffcd>] dm_setup_md_queue+0x36/0xaa [dm_mod]
[<ffffffffa01a60e6>] table_load+0x1bd/0x2c8 [dm_mod]
[<ffffffffa01a7026>] ctl_ioctl+0x1d6/0x236 [dm_mod]
[<ffffffffa01a5f29>] ? table_clear+0xaa/0xaa [dm_mod]
[<ffffffffa01a7099>] dm_ctl_ioctl+0x13/0x17 [dm_mod]
[<ffffffff811479fc>] do_vfs_ioctl+0x3fb/0x441
[<ffffffff811b643c>] ? file_has_perm+0x8a/0x99
[<ffffffff81147aa0>] sys_ioctl+0x5e/0x82
[<ffffffff812010be>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff814310d9>] system_call_fastpath+0x16/0x1b
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| b67bfe0d42cac56c512dd5da4b1b347a23f4b70a |
|
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>
|
| 810ecfa765f8be20c8d9c468885b3403a2232d2f |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: make blkcg_print_blkgs() grab q locks instead of blkcg lock
Instead of holding blkcg->lock while walking ->blkg_list and executing
prfill(), RCU walk ->blkg_list and hold the blkg's queue lock while
executing prfill(). This makes prfill() implementations easier as
stats are mostly protected by queue lock.
This will be used to implement hierarchical stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 16b3de6652c7aef151f38726faf90f0dbc9e9c71 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge()
Implement blkg_[rw]stat_recursive_sum() and blkg_[rw]stat_merge().
The former two collect the [rw]stats designated by the target policy
data and offset from the pd's subtree. The latter two add one
[rw]stat to another.
Note that the recursive sum functions require the queue lock to be
held on entry to make blkg online test reliable. This is necessary to
properly handle stats of a dying blkg.
These will be used to implement hierarchical stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| b50da39f51139f81b3115d0f9d8632507f802755 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: export __blkg_prfill_rwstat()
Hierarchical stats for cfq-iosched will need __blkg_prfill_rwstat().
Export it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
|
| f427d909648aa592c9588d0f66b5b457752a0cd1 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: implement blkcg_policy->on/offline_pd_fn() and blkcg_gq->online
Add two blkcg_policy methods, ->online_pd_fn() and ->offline_pd_fn(),
which are invoked as the policy_data gets activated and deactivated
while holding both blkcg and q locks.
Also, add blkcg_gq->online bool, which is set and cleared as the
blkcg_gq gets activated and deactivated. This flag also is toggled
while holding both blkcg and q locks.
These will be used to implement hierarchical stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| b276a876a014c5fa58a16f247c0933f6c42112e3 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: add blkg_policy_data->plid
Add pd->plid so that the policy a pd belongs to can be identified
easily. This will be used to implement hierarchical blkg_[rw]stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| e71357e118bdd4057e3bc020b9d80fecdd08f588 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
cfq-iosched: add leaf_weight
cfq blkcg is about to grow proper hierarchy handling, where a child
blkg's weight would nest inside the parent's. This makes tasks in a
blkg to compete against both tasks in the sibling blkgs and the tasks
of child blkgs.
We're gonna use the existing weight as the group weight which decides
the blkg's weight against its siblings. This patch introduces a new
weight - leaf_weight - which decides the weight of a blkg against the
child blkgs.
It's named leaf_weight because another way to look at it is that each
internal blkg nodes have a hidden child leaf node which contains all
its tasks and leaf_weight is the weight of the leaf node and handled
the same as the weight of the child blkgs.
This patch only adds leaf_weight fields and exposes it to userland.
The new weight isn't actually used anywhere yet. Note that
cfq-iosched currently offcially supports only single level hierarchy
and root blkgs compete with the first level blkgs - ie. root weight is
basically being used as leaf_weight. For root blkgs, the two weights
are kept in sync for backward compatibility.
v2: cfqd->root_group->leaf_weight initialization was missing from
cfq_init_queue() causing divide by zero when
!CONFIG_CFQ_GROUP_SCHED. Fix it. Reported by Fengguang.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
|
| 3c547865902e9fc30dc15941f326fd8039c6628d |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: make blkcg_gq's hierarchical
Currently a child blkg (blkcg_gq) can be created even if its parent
doesn't exist. ie. Given a blkg, it's not guaranteed that its
ancestors will exist. This makes it difficult to implement proper
hierarchy support for blkcg policies.
Always create blkgs recursively and make a child blkg hold a reference
to its parent. blkg->parent is added so that finding the parent is
easy. blkcg_parent() is also added in the process.
This change can be visible to userland. e.g. while issuing IO in a
nested cgroup didn't affect the ancestors at all, now it will
initialize all ancestor blkgs and zero stats for the request_queue
will always appear on them. While this is userland visible, this
shouldn't cause any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 93e6d5d8f5c909479623c6ab4427f038c6c3f63f |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: cosmetic updates to blkg_create()
* Rename out_* labels to err_*.
* Do ERR_PTR() conversion once in the error return path.
This patch is cosmetic and to prepare for the hierarchy support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 86cde6b62313dd221c2e5935db02de7234cb4164 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: reorganize blkg_lookup_create() and friends
Reorganize such that
* __blkg_lookup() takes bool param @update_hint to determine whether
to update hint.
* __blkg_lookup_create() no longer performs lookup before trying to
create. Renamed to blkg_create().
* blkg_lookup_create() now performs lookup and then invokes
blkg_create() if lookup fails.
* root_blkg creation in blkcg_activate_policy() updated accordingly.
Note that blkcg_activate_policy() no longer updates lookup hint if
root_blkg already exists.
Except for the last lookup hint bit which is immaterial, this is pure
reorganization and doesn't introduce any visible behavior change.
This is to prepare for proper hierarchy support.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 356d2e581032b686da0854c7f17de2027c872762 |
|
09-Jan-2013 |
Tejun Heo <tj@kernel.org> |
blkcg: fix minor bug in blkg_alloc()
blkg_alloc() was mistakenly checking blkcg_policy_enabled() twice.
The latter test should have been on whether pol->pd_init_fn() exists.
This doesn't cause actual problems because both blkcg policies
implement pol->pd_init_fn(). Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
|
| 3f3299d5c0268d6cc3f47b446e8aca436e4a5651 |
|
28-Nov-2012 |
Bart Van Assche <bvanassche@acm.org> |
block: Rename queue dead flag
QUEUE_FLAG_DEAD is used to indicate that queuing new requests must
stop. After this flag has been set queue draining starts. However,
during the queue draining phase it is still safe to invoke the
queue's request_fn, so QUEUE_FLAG_DYING is a better name for this
flag.
This patch has been generated by running the following command
over the kernel source tree:
git grep -lEw 'blk_queue_dead|QUEUE_FLAG_DEAD' |
xargs sed -i.tmp -e 's/blk_queue_dead/blk_queue_dying/g' \
-e 's/QUEUE_FLAG_DEAD/QUEUE_FLAG_DYING/g'; \
sed -i.tmp -e "s/QUEUE_FLAG_DYING$(printf \\t)*5/QUEUE_FLAG_DYING$(printf \\t)5/g" \
include/linux/blkdev.h; \
sed -i.tmp -e 's/ DEAD/ DYING/g' -e 's/dead queue/a dying queue/' \
-e 's/Dead queue/A dying queue/' block/blk-core.c
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Mike Christie <michaelc@cs.wisc.edu>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Chanho Min <chanho.min@lge.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 92fb97487a7e41b222c1417cabd1d1ab7cc3a48c |
|
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>
|
| bcf6de1b9129531215d26dd9af8331e84973bc52 |
|
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>
|
| 65c77fd9e8a1c8c3da0bbbea6b7efa3d6ef265f8 |
|
22-Oct-2012 |
Jun'ichi Nomura <j-nomura@ce.jp.nec.com> |
blkcg: stop iteration early if root_rl is the only request list
__blk_queue_next_rl() finds next request list based on blkg_list
while skipping root_blkg in the list.
OTOH, root_rl is special as it may exist even without root_blkg.
Though the later part of the function handles such a case correctly,
exiting early is good for readability of the code.
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 65635cbc37e011e71b208257a25e7c1078cd039b |
|
17-Oct-2012 |
Jun'ichi Nomura <j-nomura@ce.jp.nec.com> |
blkcg: Fix use-after-free of q->root_blkg and q->root_rl.blkg
blk_put_rl() does not call blkg_put() for q->root_rl because we
don't take request list reference on q->root_blkg.
However, if root_blkg is once attached then detached (freed),
blk_put_rl() is confused by the bogus pointer in q->root_blkg.
For example, with !CONFIG_BLK_DEV_THROTTLING &&
CONFIG_CFQ_GROUP_IOSCHED,
switching IO scheduler from cfq to deadline will cause system stall
after the following warning with 3.6:
> WARNING: at /work/build/linux/block/blk-cgroup.h:250
> blk_put_rl+0x4d/0x95()
> Modules linked in: bridge stp llc sunrpc acpi_cpufreq freq_table mperf
> ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4
> Pid: 0, comm: swapper/0 Not tainted 3.6.0 #1
> Call Trace:
> <IRQ> [<ffffffff810453bd>] warn_slowpath_common+0x85/0x9d
> [<ffffffff810453ef>] warn_slowpath_null+0x1a/0x1c
> [<ffffffff811d5f8d>] blk_put_rl+0x4d/0x95
> [<ffffffff811d614a>] __blk_put_request+0xc3/0xcb
> [<ffffffff811d71a3>] blk_finish_request+0x232/0x23f
> [<ffffffff811d76c3>] ? blk_end_bidi_request+0x34/0x5d
> [<ffffffff811d76d1>] blk_end_bidi_request+0x42/0x5d
> [<ffffffff811d7728>] blk_end_request+0x10/0x12
> [<ffffffff812cdf16>] scsi_io_completion+0x207/0x4d5
> [<ffffffff812c6fcf>] scsi_finish_command+0xfa/0x103
> [<ffffffff812ce2f8>] scsi_softirq_done+0xff/0x108
> [<ffffffff811dcea5>] blk_done_softirq+0x8d/0xa1
> [<ffffffff810915d5>] ?
> generic_smp_call_function_single_interrupt+0x9f/0xd7
> [<ffffffff8104cf5b>] __do_softirq+0x102/0x213
> [<ffffffff8108a5ec>] ? lock_release_holdtime+0xb6/0xbb
> [<ffffffff8104d2b4>] ? raise_softirq_irqoff+0x9/0x3d
> [<ffffffff81424dfc>] call_softirq+0x1c/0x30
> [<ffffffff81011beb>] do_softirq+0x4b/0xa3
> [<ffffffff8104cdb0>] irq_exit+0x53/0xd5
> [<ffffffff8102d865>] smp_call_function_single_interrupt+0x34/0x36
> [<ffffffff8142486f>] call_function_single_interrupt+0x6f/0x80
> <EOI> [<ffffffff8101800b>] ? mwait_idle+0x94/0xcd
> [<ffffffff81018002>] ? mwait_idle+0x8b/0xcd
> [<ffffffff81017811>] cpu_idle+0xbb/0x114
> [<ffffffff81401fbd>] rest_init+0xc1/0xc8
> [<ffffffff81401efc>] ? csum_partial_copy_generic+0x16c/0x16c
> [<ffffffff81cdbd3d>] start_kernel+0x3d4/0x3e1
> [<ffffffff81cdb79e>] ? kernel_init+0x1f7/0x1f7
> [<ffffffff81cdb2dd>] x86_64_start_reservations+0xb8/0xbd
> [<ffffffff81cdb3e3>] x86_64_start_kernel+0x101/0x110
This patch clears q->root_blkg and q->root_rl.blkg when root blkg
is destroyed.
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 8c7f6edbda01f1b1a2e60ad61f14fe38023e433b |
|
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>
|
| a051661ca6d134c18599498b185b667859d4339b |
|
27-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: implement per-blkg request allocation
Currently, request_queue has one request_list to allocate requests
from regardless of blkcg of the IO being issued. When the unified
request pool is used up, cfq proportional IO limits become meaningless
- whoever grabs the next request being freed wins the race regardless
of the configured weights.
This can be easily demonstrated by creating a blkio cgroup w/ very low
weight, put a program which can issue a lot of random direct IOs there
and running a sequential IO from a different cgroup. As soon as the
request pool is used up, the sequential IO bandwidth crashes.
This patch implements per-blkg request_list. Each blkg has its own
request_list and any IO allocates its request from the matching blkg
making blkcgs completely isolated in terms of request allocation.
* Root blkcg uses the request_list embedded in each request_queue,
which was renamed to @q->root_rl from @q->rq. While making blkcg rl
handling a bit harier, this enables avoiding most overhead for root
blkcg.
* Queue fullness is properly per request_list but bdi isn't blkcg
aware yet, so congestion state currently just follows the root
blkcg. As writeback isn't aware of blkcg yet, this works okay for
async congestion but readahead may get the wrong signals. It's
better than blkcg completely collapsing with shared request_list but
needs to be improved with future changes.
* After this change, each block cgroup gets a full request pool making
resource consumption of each cgroup higher. This makes allowing
non-root users to create cgroups less desirable; however, note that
allowing non-root users to directly manage cgroups is already
severely broken regardless of this patch - each block cgroup
consumes kernel memory and skews IO weight (IO weights are not
hierarchical).
v2: queue-sysfs.txt updated and patch description udpated as suggested
by Vivek.
v3: blk_get_rl() wasn't checking error return from
blkg_lookup_create() and may cause oops on lookup failure. Fix it
by falling back to root_rl on blkg lookup failures. This problem
was spotted by Rakesh Iyer <rni@google.com>.
v4: Updated to accomodate 458f27a982 "block: Avoid missed wakeup in
request waitqueue". blk_drain_queue() now wakes up waiters on all
blkg->rl on the target queue.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| b1208b56f31408f7d8381ff5d08e970aa5ee761c |
|
05-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: inline bio_blkcg() and friends
Make bio_blkcg() and friends inline. They all are very simple and
used only in few places.
This patch is to prepare for further updates to request allocation
path.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 159749937a3e1605068a454b1607cdc5714f16e6 |
|
05-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: make root blkcg allocation use %GFP_KERNEL
Currently, blkcg_activate_policy() depends on %GFP_ATOMIC allocation
from __blkg_lookup_create() for root blkcg creation. This could make
policy fail unnecessarily.
Make blkg_alloc() take @gfp_mask, __blkg_lookup_create() take an
optional @new_blkg for preallocated blkg, and blkcg_activate_policy()
preload radix tree and preallocate blkg with %GFP_KERNEL before trying
to create the root blkg.
v2: __blkg_lookup_create() was returning %NULL on blkg alloc failure
instead of ERR_PTR() value. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 13589864be74736ca4e6def7376742eb1d2099bf |
|
05-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: __blkg_lookup_create() doesn't need radix preload
There's no point in calling radix_tree_preload() if preloading doesn't
use more permissible GFP mask. Drop preloading from
__blkg_lookup_create().
While at it, drop sparse locking annotation which no longer applies.
v2: Vivek pointed out the odd preload usage. Instead of updating,
just drop it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 27e1f9d1cc87be4e53c6eb7158cafc21c4b85a14 |
|
05-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: drop local variable @q from blkg_destroy()
blkg_destroy() caches @blkg->q in local variable @q. While there are
two places which needs @blkg->q, only lockdep_assert_held() used the
local variable leading to unused local variable warning if lockdep is
configured out. Drop the local variable and just use @blkg->q
directly.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Rakesh Iyer <rni@google.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 9b2ea86bc9e940950a088e9795ab28f006e73276 |
|
04-Jun-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: fix blkg_alloc() failure path
When policy data allocation fails in the middle, blkg_alloc() invokes
blkg_free() to destroy the half constructed blkg. This ends up
calling pd_exit_fn() on policy datas which didn't go through
pd_init_fn(). Fix it by making blkg_alloc() call pd_init_fn()
immediately after each policy data allocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| a637120e49021d197e9578cba545bbaa459cbb51 |
|
20-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: use radix tree to index blkgs from blkcg
blkg lookup is currently performed by traversing linked list anchored
at blkcg->blkg_list. This is very unscalable and with blk-throttle
enabled and enough request queues on the system, this can get very
ugly quickly (blk-throttle performs look up on every bio submission).
This patch makes blkcg use radix tree to index blkgs combined with
simple last-looked-up hint. This is mostly identical to how icqs are
indexed from ioc.
Note that because __blkg_lookup() may be invoked without holding queue
lock, hint is only updated from __blkg_lookup_create(). Due to cfq's
cfqq caching, this makes hint updates overly lazy. This will be
improved with scheduled blkcg aware request allocation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 496fb7806d616185a46865a4f3a20ef19dc6c7e3 |
|
20-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
__blkg_lookup_create() leaked blkcg->css ref if blkg allocation
failed. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| f9fcc2d3919b8eb575b3cee9274feefafb641bca |
|
16-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: collapse blkcg_policy_ops into blkcg_policy
There's no reason to keep blkcg_policy_ops separate. Collapse it into
blkcg_policy.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| f95a04afa80c0f4ddd645ef6a84ed118b5d1ad46 |
|
16-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: embed struct blkg_policy_data in policy specific data
Currently blkg_policy_data carries policy specific data as char flex
array instead of being embedded in policy specific data. This was
forced by oddities around blkg allocation which are all gone now.
This patch makes blkg_policy_data embedded in policy specific data -
throtl_grp and cfq_group so that it's more conventional and consistent
with how io_cq is handled.
* blkcg_policy->pdata_size is renamed to ->pd_size.
* Functions which used to take void *pdata now takes struct
blkg_policy_data *pd.
* blkg_to_pdata/pdata_to_blkg() updated to blkg_to_pd/pd_to_blkg().
* Dummy struct blkg_policy_data definition added. Dummy
pdata_to_blkg() definition was unused and inconsistent with the
non-dummy version - correct dummy pd_to_blkg() added.
* throtl and cfq updated accordingly.
* As dummy blkg_to_pd/pd_to_blkg() are provided,
blkg_to_cfqg/cfqg_to_blkg() don't need to be ifdef'd. Moved outside
ifdef block.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 3c798398e393e5f9502dbab2b51e6c25e2e8f2ac |
|
16-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: mass rename of blkcg API
During the recent blkcg cleanup, most of blkcg API has changed to such
extent that mass renaming wouldn't cause any noticeable pain. Take
the chance and cleanup the naming.
* Rename blkio_cgroup to blkcg.
* Drop blkio / blkiocg prefixes and consistently use blkcg.
* Rename blkio_group to blkcg_gq, which is consistent with io_cq but
keep the blkg prefix / variable name.
* Rename policy method type and field names to signify they're dealing
with policy data.
* Rename blkio_policy_type to blkcg_policy.
This patch doesn't cause any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 54e7ed12bad1e3aa2a28558fab6850240465f973 |
|
16-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: remove blkio_group->path[]
blkio_group->path[] stores the path of the associated cgroup and is
used only for debug messages. Just format the path from blkg->cgroup
when printing debug messages.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 6d18b008daf46bcd82b8ae250aae0785f9714096 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: shoot down blkgs if all policies are deactivated
There's no reason to keep blkgs around if no policy is activated for
the queue. This patch moves queue locking out of blkg_destroy_all()
and call it from blkg_deactivate_policy() on deactivation of the last
policy on the queue.
This change was suggested by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 3c96cb32d318f323c1bf972a4c66821f8499e34d |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: drop stuff unused after per-queue policy activation update
* All_q_list is unused. Drop all_q_{mutex|list}.
* @for_root of blkg_lookup_create() is always %false when called from
outside blk-cgroup.c proper. Factor out __blkg_lookup_create() so
that it doesn't check whether @q is bypassing and use the
underscored version for the @for_root callsite.
* blkg_destroy_all() is used only from blkcg proper and @destroy_root
is always %true. Make it static and drop @destroy_root.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| a2b1693bac45ea3fe3ba612fd22c45f17449f610 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: implement per-queue policy activation
All blkcg policies were assumed to be enabled on all request_queues.
Due to various implementation obstacles, during the recent blkcg core
updates, this was temporarily implemented as shooting down all !root
blkgs on elevator switch and policy [de]registration combined with
half-broken in-place root blkg updates. In addition to being buggy
and racy, this meant losing all blkcg configurations across those
events.
Now that blkcg is cleaned up enough, this patch replaces the temporary
implementation with proper per-queue policy activation. Each blkcg
policy should call the new blkcg_[de]activate_policy() to enable and
disable the policy on a specific queue. blkcg_activate_policy()
allocates and installs policy data for the policy for all existing
blkgs. blkcg_deactivate_policy() does the reverse. If a policy is
not enabled for a given queue, blkg printing / config functions skip
the respective blkg for the queue.
blkcg_activate_policy() also takes care of root blkg creation, and
cfq_init_queue() and blk_throtl_init() are updated accordingly.
This replaces blkcg_bypass_{start|end}() and update_root_blkg_pd()
unnecessary. Dropped.
v2: cfq_init_queue() was returning uninitialized @ret on root_group
alloc failure if !CONFIG_CFQ_GROUP_IOSCHED. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 80fd99792b0b9f162abdf3da12fb10eb9eb5f321 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
Currently, blkg_lookup() doesn't check @q bypass state. This patch
updates blk_queue_bypass_start() to do synchronize_rcu() before
returning and updates blkg_lookup() to check blk_queue_bypass() and
return %NULL if bypassing. This ensures blkg_lookup() returns %NULL
if @q is bypassing.
This is to guarantee that nobody is accessing policy data while @q is
bypassing, which is necessary to allow replacing blkio_cgroup->pd[] in
place on policy [de]activation.
v2: Added more comments explaining bypass guarantees as suggested by
Vivek.
v3: Added more comments explaining why there's no synchronize_rcu() in
blk_cleanup_queue() as suggested by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| da8b066262e12d1d0a3b1e6d3486e500169bf730 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: make blkg_conf_prep() take @pol and return with queue lock held
Add @pol to blkg_conf_prep() and let it return with queue lock held
(to be released by blkg_conf_finish()). Note that @pol isn't used
yet.
This is to prepare for per-queue policy activation and doesn't cause
any visible difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 8bd435b30ecacb69bbb8b2d3e251f770b807c5b2 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: remove static policy ID enums
Remove BLKIO_POLICY_* enums and let blkio_policy_register() allocate
@pol->plid dynamically on registration. The maximum number of blkcg
policies which can be registered at the same time is defined by
BLKCG_MAX_POLS constant added to include/linux/blkdev.h.
Note that blkio_policy_register() now may fail. Policy init functions
updated accordingly and unnecessary ifdefs removed from cfq_init().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| ec399347d39fb2337ebace928cf4a2855bd0ec37 |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: use @pol instead of @plid in update_root_blkg_pd() and blkcg_print_blkgs()
The two functions were taking "enum blkio_policy_id plid". Make them
take "const struct blkio_policy_type *pol" instead.
This is to prepare for per-queue policy activation and doesn't cause
any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| bc0d6501a844392ab6ad419d7ca5af4693b6afac |
|
13-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: kill blkio_list and replace blkio_list_lock with a mutex
With blkio_policy[], blkio_list is redundant and hinders with
per-queue policy activation. Remove it. Also, replace
blkio_list_lock with a mutex blkcg_pol_mutex and let it protect the
whole [un]registration.
This is to prepare for per-queue policy activation and doesn't cause
any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 5bc4afb1ec6aa562fac4d9aba34d957ee42f5813 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: drop BLKCG_STAT_{PRIV|POL|OFF} macros
Now that all stat handling code lives in policy implementations,
there's no need to encode policy ID in cft->private.
* Export blkcg_prfill_[rw]stat() from blkcg, remove
blkcg_print_[rw]stat(), and implement cfqg_print_[rw]stat() which
use hard-code BLKIO_POLICY_PROP.
* Use cft->private for offset of the target field directly and drop
BLKCG_STAT_{PRIV|POL|OFF}().
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| d366e7ec41882791c970dfb7c67b737be8c3a174 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: pass around pd->pdata instead of pd itself in prfill functions
Now that all conf and stat fields are moved into policy specific
blkio_policy_data->pdata areas, there's no reason to use
blkio_policy_data itself in prfill functions. Pass around @pd->pdata
instead of @pd.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 3381cb8d2ef1523dbaeec99161d766c25f1e52d6 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move blkio_group_conf->weight to cfq
blkio_group_conf->weight is owned by cfq and has no reason to be
defined in blkcg core. Replace it with cfq_group->dev_weight and let
conf setting functions directly set it. If dev_weight is zero, the
cfqg doesn't have device specific weight configured.
Also, rename BLKIO_WEIGHT_* constants to CFQ_WEIGHT_* and rename
blkio_cgroup->weight to blkio_cgroup->cfq_weight. We eventually want
per-policy storage in blkio_cgroup but just mark the ownership of the
field for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 8a3d26151f24e2a2ffa550890144c3d54d2edb15 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move blkio_group_stats_cpu and friends to blk-throttle.c
blkio_group_stats_cpu is used only by blk-throtl and has no reason to
be defined in blkcg core.
* Move blkio_group_stats_cpu to blk-throttle.c and rename it to
tg_stats_cpu.
* blkg_policy_data->stats_cpu is replaced with throtl_grp->stats_cpu.
prfill functions updated accordingly.
* All related macros / functions are renamed so that they have tg_
prefix and the unnecessary @pol arguments are dropped.
* Per-cpu stats allocation code is also moved from blk-cgroup.c to
blk-throttle.c and gets simplified to only deal with
BLKIO_POLICY_THROTL. percpu stat free is performed by the exit
method throtl_exit_blkio_group().
* throtl_reset_group_stats() implemented for
blkio_reset_group_stats_fn method so that tg->stats_cpu can be
reset.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 155fead9b6347ead90e0b0396cb108a6ba6126c6 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move blkio_group_stats to cfq-iosched.c
blkio_group_stats contains only fields used by cfq and has no reason
to be defined in blkcg core.
* Move blkio_group_stats to cfq-iosched.c and rename it to cfqg_stats.
* blkg_policy_data->stats is replaced with cfq_group->stats.
blkg_prfill_[rw]stat() are updated to use offset against pd->pdata
instead.
* All related macros / functions are renamed so that they have cfqg_
prefix and the unnecessary @pol arguments are dropped.
* All stat functions now take cfq_group * instead of blkio_group *.
* lockdep assertion on queue lock dropped. Elevator runs under queue
lock by default. There isn't much to be gained by adding lockdep
assertions at stat function level.
* cfqg_stats_reset() implemented for blkio_reset_group_stats_fn method
so that cfqg->stats can be reset.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 9ade5ea4ce57d3596eaee6a57cd212a483674058 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: add blkio_policy_ops operations for exit and stat reset
Add blkio_policy_ops->blkio_exit_group_fn() and
->blkio_reset_group_stats_fn(). These will be used to further
modularize blkcg policy implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 41b38b6d540f951c49315d8573e6f6195a6e736d |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: cfq doesn't need per-cpu dispatch stats
blkio_group_stats_cpu is used to count dispatch stats using per-cpu
counters. This is used by both blk-throtl and cfq-iosched but the
sharing is rather silly.
* cfq-iosched doesn't need per-cpu dispatch stats. cfq always updates
those stats while holding queue_lock.
* blk-throtl needs per-cpu dispatch stats but only service_bytes and
serviced. It doesn't make use of sectors.
This patch makes cfq add and use global stats for service_bytes,
serviced and sectors, removes per-cpu sectors counter and moves
per-cpu stat printing code to blk-throttle.c.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 629ed0b10209ffc4e1d439e5508d52d5e3a090b8 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move statistics update code to policies
As with conf/stats file handling code, there's no reason for stat
update code to live in blkcg core with policies calling into update
them. The current organization is both inflexible and complex.
This patch moves stat update code to specific policies. All
blkiocg_update_*_stats() functions which deal with BLKIO_POLICY_PROP
stats are collapsed into their cfq_blkiocg_update_*_stats()
counterparts. blkiocg_update_dispatch_stats() is used by both
policies and duplicated as throtl_update_dispatch_stats() and
cfq_blkiocg_update_dispatch_stats(). This will be cleaned up later.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 60c2bc2d5a12369deef395cda41638d7e6b6bf19 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move conf/stat file handling code to policies
blkcg conf/stat handling is convoluted in that details which belong to
specific policy implementations are all out in blkcg core and then
policies hook into core layer to access and manipulate confs and
stats. This sadly achieves both inflexibility (confs/stats can't be
modified without messing with blkcg core) and complexity (all the
call-ins and call-backs).
The previous patches restructured conf and stat handling code such
that they can be separated out. This patch relocates the file
handling part. All conf/stat file handling code which belongs to
BLKIO_POLICY_PROP is moved to cfq-iosched.c and all
BKLIO_POLICY_THROTL code to blk-throtl.c.
The move is verbatim except for blkio_update_group_{weight|bps|iops}()
callbacks which relays conf changes to policies. The configuration
settings are handled in policies themselves so the relaying isn't
necessary. Conf setting functions are modified to directly call
per-policy update functions and the relaying mechanism is dropped.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 44ea53de46a8b01a65ae6217f47e00b516725190 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: implement blkio_policy_type->cftypes
Add blkiop->cftypes which is added and removed together with the
policy. This will be used to move conf/stat handling to the policies.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 829fdb50004de78f1bd187e428d72edcd9721cb8 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: export conf/stat helpers to prepare for reorganization
conf/stat handling is about to be moved to policy implementation from
blkcg core. Export conf/stat helpers from blkcg core so that
blk-throttle and cfq-iosched can use them.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 726fa6945e6e5f0389bf47a790e1df734a67de54 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: simplify blkg_conf_prep()
blkg_conf_prep() implements "MAJ:MIN VAL" parsing manually, which is
unnecessary. Just use sscanf("%u:%u %llu"). This might not reject
some malformed input (extra input at the end) but we don't care.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 3a8b31d396b296df4b8594429d86d415d3409432 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: restructure blkio_group configruation setting
As part of userland interface restructuring, this patch updates
per-blkio_group configuration setting. Instead of funneling
everything through a master function which has hard-coded cases for
each config file it may handle, the common part is factored into
blkg_conf_prep() and blkg_conf_finish() and different configuration
setters are implemented using the helpers.
While this doesn't result in immediate LOC reduction, this enables
further cleanups and more modular implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| c4682aec9caaca1fcfd1dd4b59cef47af22cbdc6 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: restructure configuration printing
Similarly to the previous stat restructuring, this patch restructures
conf printing code such that,
* Conf printing uses the same helpers as stat.
* Printing function doesn't require hardcoded switching on the config
being printed. Note that this isn't complete yet for throttle
confs. The next patch will convert setting for these confs and will
complete the transition.
* Printing uses read_seq_string callback (other methods will be phased
out).
Note that blkio_group_conf.iops[2] is changed to u64 so that they can
be manipulated with the same functions. This is transitional and will
go away later.
After this patch, per-device configurations - weight, bps and iops -
use __blkg_prfill_u64() for printing which uses white space as
delimiter instead of tab.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 627f29f48158c3088cc55a25d8650cae455ff63b |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: drop blkiocg_file_write_u64()
blkiocg_file_write_u64() has single switch case. Drop
blkiocg_file_write_u64(), rename blkio_weight_write() to
blkcg_set_weight() and use it directly for .write_u64 callback.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| d3d32e69fa368e131b25ee68806aa3fd3916cec1 |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: restructure statistics printing
blkcg stats handling is a mess. None of the stats has much to do with
blkcg core but they are all implemented in blkcg core. Code sharing
is achieved by mixing common code with hard-coded cases for each stat
counter.
This patch restructures statistics printing such that
* Common logic exists as helper functions and specific print functions
use the helpers to implement specific cases.
* Printing functions serving multiple counters don't require hardcoded
switching on specific counters.
* Printing uses read_seq_string callback (other methods will be phased
out).
This change enables further cleanups and relocating stats code to the
policy implementation it belongs to.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| edcb0722c654947908388df660791abd41e6617c |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: introduce blkg_stat and blkg_rwstat
blkcg uses u64_stats_sync to avoid reading wrong u64 statistic values
on 32bit archs and some stat counters have subtypes to distinguish
read/writes and sync/async IOs. The stat code paths are confusing and
involve a lot of going back and forth between blkcg core and specific
policy implementations, and synchronization and subtype handling are
open coded in blkcg core.
This patch introduces struct blkg_stat and blkg_rwstat which, with
accompanying operations, encapsulate stat updating and accessing with
proper synchronization.
blkg_stat is simple u64 counter with 64bit read-access protection.
blkg_rwstat is the one with rw and [a]sync subcounters and takes @rw
flags to distinguish IO subtypes (%REQ_WRITE and %REQ_SYNC) and
replaces stat_sub_type indexed arrays.
All counters in blkio_group_stats and blkio_group_stats_cpu are
replaced with either blkg_stat or blkg_rwstat along with all users.
This does add one u64_stats_sync per counter and increase stats_sync
operations but they're empty/noops on 64bit archs and blkcg doesn't
have too many counters, especially with DEBUG_BLK_CGROUP off.
While the currently resulting code isn't necessarily simpler at the
moment, this will enable further clean up of blkcg stats code.
- BLKIO_STAT_{READ|WRITE|SYNC|ASYNC|TOTAL} renamed to
BLKG_RWSTAT_{READ|WRITE|SYNC|ASYNC|TOTAL}.
- blkg_stat_add() replaces blkio_add_stat() and
blkio_check_and_dec_stat(). Note that BUG_ON() on underflow in the
latter function no longer exists. It's *way* better to have
underflowed stat counters than oopsing.
- blkio_group_stats->dequeue is now a proper u64 stat counter instead
of ulong.
- reset_stats() updated to clear each stat counters individually and
BLKG_STATS_DEBUG_CLEAR_{START|SIZE} are removed.
- Some functions reconstruct rw flags from direction and sync
booleans. This will be removed by future patches.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| aaec55a002a29bf940588dc03253099a4cd543bf |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: remove unused @pol and @plid parameters
@pol to blkg_to_pdata() and @plid to blkg_lookup_create() are no
longer necessary. Drop them.
Signed-off-by: Tejun Heo <tj@kernel.org>
|
| 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>
|
| 676f7c8f84d15e94065841529016da5ab92e901b |
|
01-Apr-2012 |
Tejun Heo <tj@kernel.org> |
cgroup: relocate cftype and cgroup_subsys definitions in controllers
blk-cgroup, netprio_cgroup, cls_cgroup and tcp_memcontrol
unnecessarily define cftype array and cgroup_subsys structures at the
top of the file, which is unconventional and necessiates forward
declaration of methods.
This patch relocates those below the definitions of the methods and
removes the forward declarations. Note that forward declaration of
tcp_files[] is added in tcp_memcontrol.c for tcp_init_cgroup(). This
will be removed soon by another patch.
This patch doesn't introduce any functional change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
|
| a5567932fc926739e29e98487128080f40c61710 |
|
29-Mar-2012 |
Dan Carpenter <dan.carpenter@oracle.com> |
blkcg: change a spin_lock() to spin_lock_irq()
Smatch complains that we re-enable IRQs twice. It looks like we forgot
to disable them here on the spin_trylock() failure path. This was added
in 9f13ef678e "blkcg: use double locking instead of RCU for blkg
synchronization".
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>`
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 2b566fa55b9a94b53217c2818e6c5e5756eeb1a1 |
|
19-Mar-2012 |
Tejun Heo <tj@kernel.org> |
block: remove ioc_*_changed()
After the previous patch to cfq, there's no ioc_get_changed() user
left. This patch yanks out ioc_{ioprio|cgroup|get}_changed() and all
related stuff.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 9a9e8a26da4c2c5ddc60999bdea957935fb22b6b |
|
19-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: add blkcg->id
Add 64bit unique id to blkcg. This will be used by policies which
want blkcg identity test to tell whether the associated blkcg has
changed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| edf1b879e308d37b5b7c414476ab39f79650a253 |
|
08-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: remove blkio_group->stats_lock
With recent plug merge updates, all non-percpu stat updates happen
under queue_lock making stats_lock unnecessary to synchronize stat
updates. The only synchronization necessary is stat reading, which
can be done using u64_stats_sync instead.
This patch removes blkio_group->stats_lock and adds
blkio_group_stats->syncp for reader synchronization.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| c4c76a05382c7d05e0b911daa58a827399e9ba1a |
|
08-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: restructure blkio_get_stat()
Restructure blkio_get_stat() to prepare for removal of stats_lock.
* Define BLKIO_STAT_ARR_NR explicitly to denote which stats have
subtypes instead of using BLKIO_STAT_QUEUED.
* Separate out stat acquisition and printing. After this, there are
only two users of blkio_fill_stat(). Just open code it.
* The code was mixing MAX_KEY_LEN and MAX_KEY_LEN - 1. There's no
need to subtract one. Use MAX_KEY_LEN consistently.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 997a026c80c3cc05f82e589aced1f0011c17d376 |
|
08-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: simplify stat reset
blkiocg_reset_stats() implements stat reset for blkio.reset_stats
cgroupfs file. This feature is very unconventional and something
which shouldn't have been merged. It's only useful when there's only
one user or tool looking at the stats. As soon as multiple users
and/or tools are involved, it becomes useless as resetting disrupts
other usages. There are very good reasons why all other stats expect
readers to read values at the start and end of a period and subtract
to determine delta over the period.
The implementation is rather complex - some fields shouldn't be
cleared and it saves some fields, resets whole and restores for some
reason. Reset of percpu stats is also racy. The comment points to
64bit store atomicity for the reason but even without that stores for
zero can simply race with other CPUs doing RMW and get clobbered.
Simplify reset by
* Clear selectively instead of resetting and restoring.
* Grouping debug stat fields to be reset and using memset() over them.
* Not caring about stats_lock.
* Using memset() to reset percpu stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 5fe224d2d5fbf8f020b30d0ba69fed7856923752 |
|
08-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: don't use percpu for merged stats
With recent plug merge updates, merged stats are no longer called for
plug merges and now only updated while holding queue_lock. As
stats_lock is scheduled to be removed, there's no reason to use percpu
for merged stats. Don't use percpu for merged stats.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 1cd9e039fc258f91fe38b97b3c622b13a3b8a795 |
|
08-Mar-2012 |
Vivek Goyal <vgoyal@redhat.com> |
blkcg: alloc per cpu stats from worker thread in a delayed manner
Current per cpu stat allocation assumes GFP_KERNEL allocation flag. But in
IO path there are times when we want GFP_NOIO semantics. As there is no
way to pass the allocation flags to alloc_percpu(), this patch delays the
allocation of stats using a worker thread.
v2-> tejun suggested following changes. Changed the patch accordingly.
- move alloc_node location in structure
- reduce the size of names of some of the fields
- Reduce the scope of locking of alloc_list_lock
- Simplified stat_alloc_fn() by allocating stats for all
policies in one go and then assigning these to a group.
v3 -> Andrew suggested to put some comments in the code. Also raised
concerns about trying to allocate infinitely in case of allocation
failure. I have changed the logic to sleep for 10ms before retrying.
That should take care of non-preemptible UP kernels.
v4 -> Tejun had more suggestions.
- drop list_for_each_entry_all()
- instead of msleep() use queue_delayed_work()
- Some cleanups realted to more compact coding.
v5-> tejun suggested more cleanups leading to more compact code.
tj: - Relocated pcpu_stats into blkio_stat_alloc_fn().
- Minor comment update.
- This also fixes suspicious RCU usage warning caused by invoking
cgroup_path() from blkg_alloc() without holding RCU read lock.
Now that blkg_alloc() doesn't require sleepable context, RCU
read lock from blkg_lookup_create() is maintained throughout
blkg_alloc().
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 4f85cb96d9d2fbbb7160db855a6beee1baced5e5 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
block: make block cgroup policies follow bio task association
Implement bio_blkio_cgroup() which returns the blkcg associated with
the bio if exists or %current's blkcg, and use it in blk-throttle and
cfq-iosched propio. This makes both cgroup policies honor task
association for the bio instead of always assuming %current.
As nobody is using bio_set_task() yet, this doesn't introduce any
behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| c875f4d0250a1f070fa26087a73bdd8f54c48100 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: drop unnecessary RCU locking
Now that blkg additions / removals are always done under both q and
blkcg locks, the only places RCU locking is necessary are
blkg_lookup[_create]() for lookup w/o blkcg lock. This patch drops
unncessary RCU locking replacing it with plain blkcg locking as
necessary.
* blkiocg_pre_destroy() already perform proper locking and don't need
RCU. Dropped.
* blkio_read_blkg_stats() now uses blkcg->lock instead of RCU read
lock. This isn't a hot path.
* Now unnecessary synchronize_rcu() from queue exit paths removed.
This makes q->nr_blkgs unnecessary. Dropped.
* RCU annotation on blkg->q removed.
-v2: Vivek pointed out that blkg_lookup_create() still needs to be
called under rcu_read_lock(). Updated.
-v3: After the update, stats_lock locking in blkio_read_blkg_stats()
shouldn't be using _irq variant as it otherwise ends up enabling
irq while blkcg->lock is locked. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 9f13ef678efd977487fc0c2e489f17c9a8c67a3e |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: use double locking instead of RCU for blkg synchronization
blkgs are chained from both blkcgs and request_queues and thus
subjected to two locks - blkcg->lock and q->queue_lock. As both blkcg
and q can go away anytime, locking during removal is tricky. It's
currently solved by wrapping removal inside RCU, which makes the
synchronization complex. There are three locks to worry about - the
outer RCU, q lock and blkcg lock, and it leads to nasty subtle
complications like conditional synchronize_rcu() on queue exit paths.
For all other paths, blkcg lock is naturally nested inside q lock and
the only exception is blkcg removal path, which is a very cold path
and can be implemented as clumsy but conceptually-simple reverse
double lock dancing.
This patch updates blkg removal path such that blkgs are removed while
holding both q and blkcg locks, which is trivial for request queue
exit path - blkg_destroy_all(). The blkcg removal path,
blkiocg_pre_destroy(), implements reverse double lock dancing
essentially identical to ioc_release_fn().
This simplifies blkg locking - no half-dead blkgs to worry about. Now
unnecessary RCU annotations will be removed by the next patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| e8989fae38d9831c72b20375a206a919ca468c52 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: unify blkg's for blkcg policies
Currently, blkg is per cgroup-queue-policy combination. This is
unnatural and leads to various convolutions in partially used
duplicate fields in blkg, config / stat access, and general management
of blkgs.
This patch make blkg's per cgroup-queue and let them serve all
policies. blkgs are now created and destroyed by blkcg core proper.
This will allow further consolidation of common management logic into
blkcg core and API with better defined semantics and layering.
As a transitional step to untangle blkg management, elvswitch and
policy [de]registration, all blkgs except the root blkg are being shot
down during elvswitch and bypass. This patch adds blkg_root_update()
to update root blkg in place on policy change. This is hacky and racy
but should be good enough as interim step until we get locking
simplified and switch over to proper in-place update for all blkgs.
-v2: Root blkgs need to be updated on elvswitch too and blkg_alloc()
comment wasn't updated according to the function change. Fixed.
Both pointed out by Vivek.
-v3: v2 updated blkg_destroy_all() to invoke update_root_blkg_pd() for
all policies. This freed root pd during elvswitch before the
last queue finished exiting and led to oops. Directly invoke
update_root_blkg_pd() only on BLKIO_POLICY_PROP from
cfq_exit_queue(). This also is closer to what will be done with
proper in-place blkg update. Reported by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 03aa264ac15637b6f98374270bcdf31400965505 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: let blkcg core manage per-queue blkg list and counter
With the previous patch to move blkg list heads and counters to
request_queue and blkg, logic to manage them in both policies are
almost identical and can be moved to blkcg core.
This patch moves blkg link logic into blkg_lookup_create(), implements
common blkg unlink code in blkg_destroy(), and updates
blkg_destory_all() so that it's policy specific and can skip root
group. The updated blkg_destroy_all() is now used to both clear queue
for bypassing and elv switching, and release all blkgs on q exit.
This patch introduces a race window where policy [de]registration may
race against queue blkg clearing. This can only be a problem on cfq
unload and shouldn't be a real problem in practice (and we have many
other places where this race already exists). Future patches will
remove these unlikely races.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 4eef3049986e8397d5003916aed8cad6567a5e02 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move per-queue blkg list heads and counters to queue and blkg
Currently, specific policy implementations are responsible for
maintaining list and number of blkgs. This duplicates code
unnecessarily, and hinders factoring common code and providing blkcg
API with better defined semantics.
After this patch, request_queue hosts list heads and counters and blkg
has list nodes for both policies. This patch only relocates the
necessary fields and the next patch will actually move management code
into blkcg core.
Note that request_queue->blkg_list[] and ->nr_blkgs[] are hardcoded to
have 2 elements. This is to avoid include dependency and will be
removed by the next patch.
This patch doesn't introduce any behavior change.
-v2: Now unnecessary conditional on CONFIG_BLK_CGROUP_MODULE removed
as pointed out by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| c1768268f9424410761da57ea71107acae7b03cc |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: don't use blkg->plid in stat related functions
blkg is scheduled to be unified for all policies and thus there won't
be one-to-one mapping from blkg to policy. Update stat related
functions to take explicit @pol or @plid arguments and not use
blkg->plid.
This is painful for now but most of specific stat interface functions
will be replaced with a handful of generic helpers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 549d3aa872cd1aec1ee540fd93afd9611faa0def |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: make blkg->pd an array and move configuration and stats into it
To prepare for unifying blkgs for different policies, make blkg->pd an
array with BLKIO_NR_POLICIES elements and move blkg->conf, ->stats,
and ->stats_cpu into blkg_policy_data.
This patch doesn't introduce any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 1adaf3dde37a8b9b59ea59c5f58fed7761178383 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: move refcnt to blkcg core
Currently, blkcg policy implementations manage blkg refcnt duplicating
mostly identical code in both policies. This patch moves refcnt to
blkg and let blkcg core handle refcnt and freeing of blkgs.
* cfq blkgs now also get freed via RCU.
* cfq blkgs lose RB_EMPTY_ROOT() sanity check on blkg free. If
necessary, we can add blkio_exit_group_fn() to resurrect this.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 0381411e4b1a52cee134eb73750e5e3cc1155d09 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: let blkcg core handle policy private data allocation
Currently, blkg's are embedded in private data blkcg policy private
data structure and thus allocated and freed by policies. This leads
to duplicate codes in policies, hinders implementing common part in
blkcg core with strong semantics, and forces duplicate blkg's for the
same cgroup-q association.
This patch introduces struct blkg_policy_data which is a separate data
structure chained from blkg. Policies specifies the amount of private
data it needs in its blkio_policy_type->pdata_size and blkcg core
takes care of allocating them along with blkg which can be accessed
using blkg_to_pdata(). blkg can be determined from pdata using
pdata_to_blkg(). blkio_alloc_group_fn() method is accordingly updated
to blkio_init_group_fn().
For consistency, tg_of_blkg() and cfqg_of_blkg() are replaced with
blkg_to_tg() and blkg_to_cfqg() respectively, and functions to map in
the reverse direction are added.
Except that policy specific data now lives in a separate data
structure from blkg, this patch doesn't introduce any functional
difference.
This will be used to unify blkg's for different policies.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 923adde1be1df57cebd80c563058e503376645e8 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: clear all request_queues on blkcg policy [un]registrations
Keep track of all request_queues which have blkcg initialized and turn
on bypass and invoke blkcg_clear_queue() on all before making changes
to blkcg policies.
This is to prepare for moving blkg management into blkcg core. Note
that this uses more brute force than necessary. Finer grained shoot
down will be implemented later and given that policy [un]registration
almost never happens on running systems (blk-throtl can't be built as
a module and cfq usually is the builtin default iosched), this
shouldn't be a problem for the time being.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 5efd611351d1a847c72d74fb12ff4bd187c0cb2c |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: add blkcg_{init|drain|exit}_queue()
Currently block core calls directly into blk-throttle for init, drain
and exit. This patch adds blkcg_{init|drain|exit}_queue() which wraps
the blk-throttle functions. This is to give more control and
visiblity to blkcg core layer for proper layering. Further patches
will add logic common to blkcg policies to the functions.
While at it, collapse blk_throtl_release() into blk_throtl_exit().
There's no reason to keep them separate.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 7ee9c5620504906e98451dc9a1945b2b9e892cb8 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: let blkio_group point to blkio_cgroup directly
Currently, blkg points to the associated blkcg via its css_id. This
unnecessarily complicates dereferencing blkcg. Let blkg hold a
reference to the associated blkcg and point directly to it and disable
css_id on blkio_subsys.
This change requires splitting blkiocg_destroy() into
blkiocg_pre_destroy() and blkiocg_destroy() so that all blkg's can be
destroyed and all the blkcg references held by them dropped during
cgroup removal.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 92616b5b3a7c7fa8148df82e7ff6183056f2bfc8 |
|
05-Mar-2012 |
Vivek Goyal <vgoyal@redhat.com> |
blkcg: skip blkg printing if q isn't associated with disk
blk-cgroup printing code currently assumes that there is a device/disk
associated with every queue in the system, but modules like floppy,
can instantiate request queues without registering disk which can lead
to oops.
Skip the queue/blkg which don't have dev/disk associated with them.
-tj: Factored out backing_dev_info check into blkg_dev_name().
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 7a4dd281ec66224f802093962d1d903d86b09560 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: kill the mind-bending blkg->dev
blkg->dev is dev_t recording the device number of the block device for
the associated request_queue. It is used to identify the associated
block device when printing out configuration or stats.
This is redundant to begin with. A blkg is an association between a
cgroup and a request_queue and it of course is possible to reach
request_queue from blkg and synchronization conventions are in place
for safe q dereferencing, so this shouldn't be necessary from the
beginning. Furthermore, it's initialized by sscanf()ing the device
name of backing_dev_info. The mind boggles.
Anyways, if blkg is visible under rcu lock, we *know* that the
associated request_queue hasn't gone away yet and its bdi is
registered and alive - blkg can't be created for request_queue which
hasn't been fully initialized and it can't go away before blkg is
removed.
Let stat and conf read functions get device name from
blkg->q->backing_dev_info.dev and pass it down to printing functions
and remove blkg->dev.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 4bfd482e73b30284cb21e10834ce729fa81aa256 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: kill blkio_policy_node
Now that blkcg configuration lives in blkg's, blkio_policy_node is no
longer necessary. Kill it.
blkio_policy_parse_and_set() now fails if invoked for missing device
and functions to print out configurations are updated to print from
blkg's.
cftype_blkg_same_policy() is dropped along with other policy functions
for consistency. Its one line is open coded in the only user -
blkio_read_blkg_stats().
-v2: Update to reflect the retry-on-bypass logic change of the
previous patch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| e56da7e287967667474a58c4f60c286279e3f487 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: don't allow or retain configuration of missing devices
blkcg is very peculiar in that it allows setting and remembering
configurations for non-existent devices by maintaining separate data
structures for configuration.
This behavior is completely out of the usual norms and outright
confusing; furthermore, it uses dev_t number to match the
configuration to devices, which is unpredictable to begin with and
becomes completely unuseable if EXT_DEVT is fully used.
It is wholely unnecessary - we already have fully functional userland
mechanism to program devices being hotplugged which has full access to
device identification, connection topology and filesystem information.
Add a new struct blkio_group_conf which contains all blkcg
configurations to blkio_group and let blkio_group, which can be
created iff the associated device exists and is removed when the
associated device goes away, carry all configurations.
Note that, after this patch, all newly created blkg's will always have
the default configuration (unlimited for throttling and blkcg's weight
for propio).
This patch makes blkio_policy_node meaningless but doesn't remove it.
The next patch will.
-v2: Updated to retry after short sleep if blkg lookup/creation failed
due to the queue being temporarily bypassed as indicated by
-EBUSY return. Pointed out by Vivek.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| cd1604fab4f95f7cfc227d3955fd7ae14da61f38 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: factor out blkio_group creation
Currently both blk-throttle and cfq-iosched implement their own
blkio_group creation code in throtl_get_tg() and cfq_get_cfqg(). This
patch factors out the common code into blkg_lookup_create(), which
returns ERR_PTR value so that transitional failures due to queue
bypass can be distinguished from other failures.
* New plkio_policy_ops methods blkio_alloc_group_fn() and
blkio_link_group_fn added. Both are transitional and will be
removed once the blkg management code is fully moved into
blk-cgroup.c.
* blkio_alloc_group_fn() allocates policy-specific blkg which is
usually a larger data structure with blkg as the first entry and
intiailizes it. Note that initialization of blkg proper, including
percpu stats, is responsibility of blk-cgroup proper.
Note that default config (weight, bps...) initialization is done
from this method; otherwise, we end up violating locking order
between blkcg and q locks via blkcg_get_CONF() functions.
* blkio_link_group_fn() is called under queue_lock and responsible for
linking the blkg to the queue. blkcg side is handled by blk-cgroup
proper.
* The common blkg creation function is named blkg_lookup_create() and
blkiocg_lookup_group() is renamed to blkg_lookup() for consistency.
Also, throtl / cfq related functions are similarly [re]named for
consistency.
This simplifies blkcg policy implementations and enables further
cleanup.
-v2: Vivek noticed that blkg_lookup_create() incorrectly tested
blk_queue_dead() instead of blk_queue_bypass() leading a user of
the function ending up creating a new blkg on bypassing queue.
This is a bug introduced while relocating bypass patches before
this one. Fixed.
-v3: ERR_PTR patch folded into this one. @for_root added to
blkg_lookup_create() to allow creating root group on a bypassed
queue during elevator switch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 035d10b2fa7e5f7e9bf9465dbc39c35affd5ac32 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: add blkio_policy[] array and allow one policy per policy ID
Block cgroup policies are maintained in a linked list and,
theoretically, multiple policies sharing the same policy ID are
allowed.
This patch temporarily restricts one policy per plid and adds
blkio_policy[] array which indexes registered policy types by plid.
Both the restriction and blkio_policy[] array are transitional and
will be removed once API cleanup is complete.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| ca32aefc7f2539ed88d42763330d54ee3e61769a |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: use q and plid instead of opaque void * for blkio_group association
blkgio_group is association between a block cgroup and a queue for a
given policy. Using opaque void * for association makes things
confusing and hinders factoring of common code. Use request_queue *
and, if necessary, policy id instead.
This will help block cgroup API cleanup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 72e06c255181537d0b3e1f657a9ed81655d745b1 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: shoot down blkio_groups on elevator switch
Elevator switch may involve changes to blkcg policies. Implement
shoot down of blkio_groups.
Combined with the previous bypass updates, the end goal is updating
blkcg core such that it can ensure that blkcg's being affected become
quiescent and don't have any per-blkg data hanging around before
commencing any policy updates. Until queues are made aware of the
policies that applies to them, as an interim step, all per-policy blkg
data will be shot down.
* blk-throtl doesn't need this change as it can't be disabled for a
live queue; however, update it anyway as the scheduled blkg
unification requires this behavior change. This means that
blk-throtl configuration will be unnecessarily lost over elevator
switch. This oddity will be removed after blkcg learns to associate
individual policies with request_queues.
* blk-throtl dosen't shoot down root_tg. This is to ease transition.
Unified blkg will always have persistent root group and not shooting
down root_tg for now eases transition to that point by avoiding
having to update td->root_tg and is safe as blk-throtl can never be
disabled
-v2: Vivek pointed out that group list is not guaranteed to be empty
on return from clear function if it raced cgroup removal and
lost. Fix it by waiting a bit and retrying. This kludge will
soon be removed once locking is updated such that blkg is never
in limbo state between blkcg and request_queue locks.
blk-throtl no longer shoots down root_tg to avoid breaking
td->root_tg.
Also, Nest queue_lock inside blkio_list_lock not the other way
around to avoid introduce possible deadlock via blkcg lock.
-v3: blkcg_clear_queue() repositioned and renamed to
blkg_destroy_all() to increase consistency with later changes.
cfq_clear_queue() updated to check q->elevator before
dereferencing it to avoid NULL dereference on not fully
initialized queues (used by later change).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 32e380aedc3de454c06ce1c254fe3bea35a676e1 |
|
05-Mar-2012 |
Tejun Heo <tj@kernel.org> |
blkcg: make CONFIG_BLK_CGROUP bool
Block cgroup core can be built as module; however, it isn't too useful
as blk-throttle can only be built-in and cfq-iosched is usually the
default built-in scheduler. Scheduled blkcg cleanup requires calling
into blkcg from block core. To simplify that, disallow building blkcg
as module by making CONFIG_BLK_CGROUP bool.
If building blkcg core as module really matters, which I doubt, we can
revisit it after blkcg API cleanup.
-v2: Vivek pointed out that IOSCHED_CFQ was incorrectly updated to
depend on BLK_CGROUP. Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 11a3122f6cf2d988a77eb8883d0fc49cd013a6d5 |
|
07-Feb-2012 |
Tejun Heo <tj@kernel.org> |
block: strip out locking optimization in put_io_context()
put_io_context() performed a complex trylock dancing to avoid
deferring ioc release to workqueue. It was also broken on UP because
trylock was always assumed to succeed which resulted in unbalanced
preemption count.
While there are ways to fix the UP breakage, even the most
pathological microbench (forced ioc allocation and tight fork/exit
loop) fails to show any appreciable performance benefit of the
optimization. Strip it out. If there turns out to be workloads which
are affected by this change, simpler optimization from the discussion
thread can be applied later.
Signed-off-by: Tejun Heo <tj@kernel.org>
LKML-Reference: <1328514611.21268.66.camel@sli10-conroe>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 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>
|
| b2efa05265d62bc29f3a64400fad4b44340eedb8 |
|
14-Dec-2011 |
Tejun Heo <tj@kernel.org> |
block, cfq: unlink cfq_io_context's immediately
cic is association between io_context and request_queue. A cic is
linked from both ioc and q and should be destroyed when either one
goes away. As ioc and q both have their own locks, locking becomes a
bit complex - both orders work for removal from one but not from the
other.
Currently, cfq tries to circumvent this locking order issue with RCU.
ioc->lock nests inside queue_lock but the radix tree and cic's are
also protected by RCU allowing either side to walk their lists without
grabbing lock.
This rather unconventional use of RCU quickly devolves into extremely
fragile convolution. e.g. The following is from cfqd going away too
soon after ioc and q exits raced.
general protection fault: 0000 [#1] PREEMPT SMP
CPU 2
Modules linked in:
[ 88.503444]
Pid: 599, comm: hexdump Not tainted 3.1.0-rc10-work+ #158 Bochs Bochs
RIP: 0010:[<ffffffff81397628>] [<ffffffff81397628>] cfq_exit_single_io_context+0x58/0xf0
...
Call Trace:
[<ffffffff81395a4a>] call_for_each_cic+0x5a/0x90
[<ffffffff81395ab5>] cfq_exit_io_context+0x15/0x20
[<ffffffff81389130>] exit_io_context+0x100/0x140
[<ffffffff81098a29>] do_exit+0x579/0x850
[<ffffffff81098d5b>] do_group_exit+0x5b/0xd0
[<ffffffff81098de7>] sys_exit_group+0x17/0x20
[<ffffffff81b02f2b>] system_call_fastpath+0x16/0x1b
The only real hot path here is cic lookup during request
initialization and avoiding extra locking requires very confined use
of RCU. This patch makes cic removal from both ioc and request_queue
perform double-locking and unlink immediately.
* From q side, the change is almost trivial as ioc->lock nests inside
queue_lock. It just needs to grab each ioc->lock as it walks
cic_list and unlink it.
* From ioc side, it's a bit more difficult because of inversed lock
order. ioc needs its lock to walk its cic_list but can't grab the
matching queue_lock and needs to perform unlock-relock dancing.
Unlinking is now wholly done from put_io_context() and fast path is
optimized by using the queue_lock the caller already holds, which is
by far the most common case. If the ioc accessed multiple devices,
it tries with trylock. In unlikely cases of fast path failure, it
falls back to full double-locking dance from workqueue.
Double-locking isn't the prettiest thing in the world but it's *far*
simpler and more understandable than RCU trick without adding any
meaningful overhead.
This still leaves a lot of now unnecessary RCU logics. Future patches
will trim them.
-v2: Vivek pointed out that cic->q was being dereferenced after
cic->release() was called. Updated to use local variable @this_q
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| dc86900e0a8f665122de6faadd27fb4c6d2b3e4d |
|
14-Dec-2011 |
Tejun Heo <tj@kernel.org> |
block, cfq: move ioc ioprio/cgroup changed handling to cic
ioprio/cgroup change was handled by marking the changed state in ioc
and, on the following access to the ioc, performing RCU-protected
iteration through all cic's grabbing the matching queue_lock.
This patch moves the changed state to each cic. When ioprio or cgroup
changes, the respective bit is set on all cic's of the ioc and when
each of those cic (not ioc) is accessed, change is applied for that
specific ioc-queue pair.
This also fixes the following two race conditions between setting and
clearing of changed states.
* Missing barrier between assign/load of ioprio and ioprio_changed
allowed applying old ioprio.
* Change requests could happen between application of change and
clearing of changed variables.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 6e736be7f282fff705db7c34a15313281b372a76 |
|
14-Dec-2011 |
Tejun Heo <tj@kernel.org> |
block: make ioc get/put interface more conventional and fix race on alloction
Ignoring copy_io() during fork, io_context can be allocated from two
places - current_io_context() and set_task_ioprio(). The former is
always called from local task while the latter can be called from
different task. The synchornization between them are peculiar and
dubious.
* current_io_context() doesn't grab task_lock() and assumes that if it
saw %NULL ->io_context, it would stay that way until allocation and
assignment is complete. It has smp_wmb() between alloc/init and
assignment.
* set_task_ioprio() grabs task_lock() for assignment and does
smp_read_barrier_depends() between "ioc = task->io_context" and "if
(ioc)". Unfortunately, this doesn't achieve anything - the latter
is not a dependent load of the former. ie, if ioc itself were being
dereferenced "ioc->xxx", it would mean something (not sure what tho)
but as the code currently stands, the dependent read barrier is
noop.
As only one of the the two test-assignment sequences is task_lock()
protected, the task_lock() can't do much about race between the two.
Nothing prevents current_io_context() and set_task_ioprio() allocating
its own ioc for the same task and overwriting the other's.
Also, set_task_ioprio() can race with exiting task and create a new
ioc after exit_io_context() is finished.
ioc get/put doesn't have any reason to be complex. The only hot path
is accessing the existing ioc of %current, which is simple to achieve
given that ->io_context is never destroyed as long as the task is
alive. All other paths can happily go through task_lock() like all
other task sub structures without impacting anything.
This patch updates ioc get/put so that it becomes more conventional.
* alloc_io_context() is replaced with get_task_io_context(). This is
the only interface which can acquire access to ioc of another task.
On return, the caller has an explicit reference to the object which
should be put using put_io_context() afterwards.
* The functionality of current_io_context() remains the same but when
creating a new ioc, it shares the code path with
get_task_io_context() and always goes through task_lock().
* get_io_context() now means incrementing ref on an ioc which the
caller already has access to (be that an explicit refcnt or implicit
%current one).
* PF_EXITING inhibits creation of new io_context and once
exit_io_context() is finished, it's guaranteed that both ioc
acquisition functions return %NULL.
* All users are updated. Most are trivial but
smp_read_barrier_depends() removal from cfq_get_io_context() needs a
bit of explanation. I suppose the original intention was to ensure
ioc->ioprio is visible when set_task_ioprio() allocates new
io_context and installs it; however, this wouldn't have worked
because set_task_ioprio() doesn't have wmb between init and install.
There are other problems with this which will be fixed in another
patch.
* While at it, use NUMA_NO_NODE instead of -1 for wildcard node
specification.
-v2: Vivek spotted contamination from debug patch. Removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| bb9d97b6dffa10cec5e1ce9adbce60f3c2b5eabc |
|
13-Dec-2011 |
Tejun Heo <tj@kernel.org> |
cgroup: don't use subsys->can_attach_task() or ->attach_task()
Now that subsys->can_attach() and attach() take @tset instead of
@task, they can handle per-task operations. Convert
->can_attach_task() and ->attach_task() users to use ->can_attach()
and attach() instead. Most converions are straight-forward.
Noteworthy changes are,
* In cgroup_freezer, remove unnecessary NULL assignments to unused
methods. It's useless and very prone to get out of sync, which
already happened.
* In cpuset, PF_THREAD_BOUND test is checked for each task. This
doesn't make any practical difference but is conceptually cleaner.
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: Paul Menage <paul@paulmenage.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: James Morris <jmorris@namei.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
|
| a38eb630fa224d6fba8c14a4063174bc5e0f63bb |
|
25-Oct-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-throttle: Take blkcg->lock while traversing blkcg->policy_list
blkcg->policy_list is protected by blkcg->lock. Its not rcu protected
list. So even for readers, they need to take blkcg->lock. There are
few functions which were reading the list without taking lock. Fix it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| e060f00beee23568fe2c4faf1e88ff22edefd7b2 |
|
25-Oct-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-throttle: Free up policy node associated with deleted rule
If a rule is being deleted, free up associated policy node. Otherwise
that memory is leaked.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| ece84241b93c4693bfe0a8ec9a043a16d216d0cd |
|
19-Oct-2011 |
Tejun Heo <tj@kernel.org> |
block: fix genhd refcounting in blkio_policy_parse_and_set()
blkio_policy_parse_and_set() calls blkio_check_dev_num() to check
whether the given dev_t is valid. blkio_check_dev_num() uses
get_gendisk() for verification but never puts the returned genhd
leaking the reference.
This patch collapses blkio_check_dev_num() into its caller and updates
it such that the genhd is put before returning.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| d11bb4462c4cc6ddd45c6927c617ad79fa6fb8fc |
|
21-Sep-2011 |
Wanlong Gao <gaowanlong@cn.fujitsu.com> |
blk-cgroup: be able to remove the record of unplugged device
The bug is we're not able to remove the device from blkio cgroup's
per-device control files if it gets unplugged.
To reproduce the bug:
# mount -t cgroup -o blkio xxx /cgroup
# cd /cgroup
# echo "8:0 1000" > blkio.throttle.read_bps_device
# unplug the device
# cat blkio.throttle.read_bps_device
8:0 1000
# echo "8:0 0" > blkio.throttle.read_bps_device
-bash: echo: write error: No such device
After patching, the device removal will succeed.
Thanks for the comments of Paul, Zefan, and Vivek.
Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <paul@paulmenage.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
|
| 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>
|
| 317389a7739675aa990b7e0d750a7c435f1d25d7 |
|
23-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
cfq-iosched: Make IO merge related stats per cpu
Make BLKIO_STAT_MERGED per cpu hence gettring rid of need of taking
blkg->stats_lock.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| f0bdc8cdd9a2bcc2c84ae2a1fdbff4188b354d8d |
|
19-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Make cgroup stat reset path blkg->lock free for dispatch stats
Now dispatch stats update is lock free. But reset of these stats still
takes blkg->stats_lock and is dependent on that. As stats are per cpu,
we should be able to just reset the stats on each cpu without any locks.
(Atleast for 64bit arch).
On 32bit arch there is a small race where 64bit updates are not atomic.
The result of this race can be that in the presence of other writers,
one might not get 0 value after reset of a stat and might see something
intermediate
One can write more complicated code to cover this race like sending IPI
to other cpus to reset stats and for offline cpus, reset these directly.
Right not I am not taking that path because reset_update is more of a
debug feature and it can happen only on 32bit arch and possibility of
it happening is small. Will fix it if it becomes a real problem. For
the time being going for code simplicity.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 575969a0dd3fe65c6556bcb8f87c42303326ea55 |
|
19-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Make 64bit per cpu stats safe on 32bit arch
Some of the stats are 64bit and updation will be non atomic on 32bit
architecture. Use sequence counters on 32bit arch to make reading
of stats safe.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 5624a4e445e2ec27582984b068d7bf7f127cee10 |
|
19-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-throttle: Make dispatch stats per cpu
Currently we take blkg_stat lock for even updating the stats. So even if
a group has no throttling rules (common case for root group), we end
up taking blkg_lock, for updating the stats.
Make dispatch stats per cpu so that these can be updated without taking
blkg lock.
If cpu goes offline, these stats simply disappear. No protection has
been provided for that yet. Do we really need anything for that?
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| a23e68695593d00b35a6cddf8e9c9ec03505ecb9 |
|
19-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: move some fields of unaccounted_time file under right config option
cgroup unaccounted_time file is created only if CONFIG_DEBUG_BLK_CGROUP=y.
there are some fields which are out side this config option. Fix that.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 70087dc38cc77ca8f46059564c00338777734762 |
|
16-May-2011 |
Vivek Goyal <vgoyal@redhat.com> |
blk-throttle: Use task_subsys_state() to determine a task's blkio_cgroup
Currentlly we first map the task to cgroup and then cgroup to
blkio_cgroup. There is a more direct way to get to blkio_cgroup
from task using task_subsys_state(). Use that.
The real reason for the fix is that it also avoids a race in generic
cgroup code. During remount/umount rebind_subsystems() is called and
it can do following with and rcu protection.
cgrp->subsys[i] = NULL;
That means if somebody got hold of cgroup under rcu and then it tried
to do cgroup->subsys[] to get to blkio_cgroup, it would get NULL which
is wrong. I was running into this race condition with ltp running on a
upstream derived kernel and that lead to crash.
So ideally we should also fix cgroup generic code to wait for rcu
grace period before setting pointer to NULL. Li Zefan is not very keen
on introducing synchronize_wait() as he thinks it will slow
down moun/remount/umount operations.
So for the time being atleast fix the kernel crash by taking a more
direct route to blkio_cgroup.
One tester had reported a crash while running LTP on a derived kernel
and with this fix crash is no more seen while the test has been
running for over 6 days.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 25985edcedea6396277003854657b5f3cb31a628 |
|
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>
|
| 9026e521c0da0731eb31f9f9022dd00cc3cd8885 |
|
22-Mar-2011 |
Justin TerAvest <teravest@google.com> |
blk-cgroup: Only give unaccounted_time under debug
This change moves unaccounted_time to only be reported when
CONFIG_DEBUG_BLK_CGROUP is true.
Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 167400d34070ebbc408dc0f447c4ddb4bf837360 |
|
12-Mar-2011 |
Justin TerAvest <teravest@google.com> |
blk-cgroup: Add unaccounted time to timeslice_used.
There are two kind of times that tasks are not charged for: the first
seek and the extra time slice used over the allocated timeslice. Both
of these exported as a new unaccounted_time stat.
I think it would be good to have this reported in 'time' as well, but
that is probably a separate discussion.
Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| bdc85df7a8417b9893443ff5520804699416b6f3 |
|
15-Nov-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Allow creation of hierarchical cgroups
o Allow hierarchical cgroup creation for blkio controller
o Currently we disallow it as both the io controller policies (throttling
as well as proportion bandwidth) do not support hierarhical accounting
and control. But the flip side is that blkio controller can not be used with
libvirt as libvirt creates a cgroup hierarchy deeper than 1 level.
<top-level-cgroup-dir>/<controller>/libvirt/qemu/<virtual-machine-groups>
o So this patch will allow creation of cgroup hierarhcy but at the backend
everything will be treated as flat. So if somebody created a an hierarchy
like as follows.
root
/ \
test1 test2
|
test3
CFQ and throttling will practically treat all groups at same level.
pivot
/ | \ \
root test1 test2 test3
o Once we have actual support for hierarchical accounting and control
then we can introduce another cgroup tunable file "blkio.use_hierarchy"
which will be 0 by default but if user wants to enforce hierarhical
control then it can be set to 1. This way there should not be any
ABI problems down the line.
o The only not so pretty part is introduction of extra file "use_hierarchy"
down the line. Kame-san had mentioned that hierarhical accounting is
expensive in memory controller hence they keep it off by default. I
suspect same will be the case for IO controller also as for each IO
completion we shall have to account IO through hierarchy up to the root.
if yes, then it probably is not a very bad idea to introduce this extra
file so that it will be used only when somebody needs it and some people
might enable hierarchy only in part of the hierarchy.
o This is how basically memory controller also uses "use_hierarhcy" and
they also allowed creation of hierarchies when actual backend support
was not available.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Reviewed-by: Ciju Rajan K <ciju@linux.vnet.ibm.com>
Tested-by: Ciju Rajan K <ciju@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 9355aede5a3c4975e0ba8bbfe2b9d1fd73308916 |
|
01-Oct-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blkio-throttle: limit max iops value to UINT_MAX
- Limit max iops value to UINT_MAX and return error to user if value is more
than that instead of accepting bigger values and truncating implicitly.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| fe0714377ee2ca161bf2afb7773e22f15f1786d4 |
|
01-Oct-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Recalculate the throttled bio dispatch time upon throttle limit change
o Currently any cgroup throttle limit changes are processed asynchronousy and
the change does not take affect till a new bio is dispatched from same group.
o It might happen that a user sets a redicuously low limit on throttling.
Say 1 bytes per second on reads. In such cases simple operations like mount
a disk can wait for a very long time.
o Once bio is throttled, there is no easy way to come out of that wait even if
user increases the read limit later.
o This patch fixes it. Now if a user changes the cgroup limits, we recalculate
the bio dispatch time according to new limits.
o Can't take queueu lock under blkcg_lock, hence after the change I wake
up the dispatch thread again which recalculates the time. So there are some
variables being synchronized across two threads without lock and I had to
make use of barriers. Hoping I have used barriers correctly. Any review of
memory barrier code especially will help.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 61014e96e6ed55b8db0af31574eec2a75d4e8755 |
|
01-Oct-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: deletion of a cgroup was causes oops
o Now a cgroup list of blkg elements can contain blkg from multiple policies.
Before sending an unlink event, make sure blkg belongs to they policy. If
policy does not own the blkg, do not send update for this blkg.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 13f98250f587b7defa39ed738dfa74b600e46e7b |
|
01-Oct-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n
Currently throttling related files were visible even if user had disabled
throttling using config options. It was switching off background throttling
of bio but not the cgroup files. This patch fixes it.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 7702e8f45b0a3bb262b9366c60beb5445758d94c |
|
15-Sep-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: cgroup changes for IOPS limit support
o cgroup changes for IOPS throttling rules.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 4c9eefa16c6f124ffcc736cb719b24ea27f85017 |
|
15-Sep-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Introduce cgroup changes for throttling policy
o cgroup chagnes for throttle policy.
o Introduces READ and WRITE bytes per second throttling rules.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 062a644d6121d5e2f51c0b2ca0cbc5155ebf845b |
|
15-Sep-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Prepare the base for supporting more than one IO control policies
o This patch prepares the base for introducing new IO control policies.
Currently all the code is written knowing there is only one policy
and that is proportional bandwidth. Creating infrastructure for newer
policies to come in.
o Also there were many functions which were generated using macro. It was
very confusing. Got rid of those.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| af41d7bd9b685ab4e8f930627874ba4f4728e128 |
|
15-Sep-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: Kill the header printed at the start of blkio.weight_device file
o Kill extra "dev weight" header which is printed when somebody reads
blkio.weight_device file. This really seems to be out of convention. No other
blkio files are printing any header at the start of file. I think it is ok
to just print values and how to interpret values should be part of
documentation.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 96aa1b419d47286db446f292cf898bb1a8b27f24 |
|
23-Aug-2010 |
Ciju Rajan K <ciju@linux.vnet.ibm.com> |
blkio: Fix return code for mkdir calls
If the cgroup hierarchy for blkio control groups is deeper than two
levels, kernel should not allow the creation of further levels. mkdir
system call does not except EINVAL as a return value. This patch
replaces EINVAL with more appropriate EPERM
Signed-off-by: Ciju Rajan K <ciju@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
|
| 0341509fdfc9519f7de6aabc5dd23217cef72b73 |
|
07-May-2010 |
Li Zefan <lizf@cn.fujitsu.com> |
blk-cgroup: Fix an RCU warning in blkiocg_create()
with CONFIG_PROVE_RCU=y, a warning can be triggered:
# mount -t cgroup -o blkio xxx /mnt
# mkdir /mnt/subgroup
...
kernel/cgroup.c:4442 invoked rcu_dereference_check() without protection!
...
To fix this, we avoid caling css_depth() here, which is a bit simpler
than the original code.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 0f3942a39ed768c967cb71ea0e9be7fc94112713 |
|
03-May-2010 |
Jens Axboe <jens.axboe@oracle.com> |
block: kill some useless goto's in blk-cgroup.c
goto has its place, but lets cut back on some of the more
frivolous uses of it.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| afc24d49c1e5dbeef745c1c1246f5ae6ebd97c71 |
|
26-Apr-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blk-cgroup: config options re-arrangement
This patch fixes few usability and configurability issues.
o All the cgroup based controller options are configurable from
"Genral Setup/Control Group Support/" menu. blkio is the only exception.
Hence make this option visible in above menu and make it configurable from
there to bring it inline with rest of the cgroup based controllers.
o Get rid of CONFIG_DEBUG_CFQ_IOSCHED.
This option currently does two things.
- Enable printing of cgroup paths in blktrace
- Enables CONFIG_DEBUG_BLK_CGROUP, which in turn displays additional stat
files in cgroup.
If we are using group scheduling, blktrace data is of not really much use
if cgroup information is not present. To get this data, currently one has to
also enable CONFIG_DEBUG_CFQ_IOSCHED, which in turn brings the overhead of
all the additional debug stat files which is not desired.
Hence, this patch moves printing of cgroup paths under
CONFIG_CFQ_GROUP_IOSCHED.
This allows us to get rid of CONFIG_DEBUG_CFQ_IOSCHED completely. Now all
the debug stat files are controlled only by CONFIG_DEBUG_BLK_CGROUP which
can be enabled through config menu.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Divyesh Shah <dpshah@google.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| e5ff082e8a68d9a6874990597497c7e6a96ad752 |
|
26-Apr-2010 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Fix another BUG_ON() crash due to cfqq movement across groups
o Once in a while, I was hitting a BUG_ON() in blkio code. empty_time was
assuming that upon slice expiry, group can't be marked empty already (except
forced dispatch).
But this assumption is broken if cfqq can move (group_isolation=0) across
groups after receiving a request.
I think most likely in this case we got a request in a cfqq and accounted
the rq in one group, later while adding the cfqq to tree, we moved the queue
to a different group which was already marked empty and after dispatch from
slice we found group already marked empty and raised alarm.
This patch does not error out if group is already marked empty. This can
introduce some empty_time stat error only in case of group_isolation=0. This
is better than crashing. In case of group_isolation=1 we should still get
same stats as before this patch.
[ 222.308546] ------------[ cut here ]------------
[ 222.309311] kernel BUG at block/blk-cgroup.c:236!
[ 222.309311] invalid opcode: 0000 [#1] SMP
[ 222.309311] last sysfs file: /sys/devices/virtual/block/dm-3/queue/scheduler
[ 222.309311] CPU 1
[ 222.309311] Modules linked in: dm_round_robin dm_multipath qla2xxx scsi_transport_fc dm_zero dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
[ 222.309311]
[ 222.309311] Pid: 4780, comm: fio Not tainted 2.6.34-rc4-blkio-config #68 0A98h/HP xw8600 Workstation
[ 222.309311] RIP: 0010:[<ffffffff8121ad88>] [<ffffffff8121ad88>] blkiocg_set_start_empty_time+0x50/0x83
[ 222.309311] RSP: 0018:ffff8800ba6e79f8 EFLAGS: 00010002
[ 222.309311] RAX: 0000000000000082 RBX: ffff8800a13b7990 RCX: ffff8800a13b7808
[ 222.309311] RDX: 0000000000002121 RSI: 0000000000000082 RDI: ffff8800a13b7a30
[ 222.309311] RBP: ffff8800ba6e7a18 R08: 0000000000000000 R09: 0000000000000001
[ 222.309311] R10: 000000000002f8c8 R11: ffff8800ba6e7ad8 R12: ffff8800a13b78ff
[ 222.309311] R13: ffff8800a13b7990 R14: 0000000000000001 R15: ffff8800a13b7808
[ 222.309311] FS: 00007f3beec476f0(0000) GS:ffff880001e40000(0000) knlGS:0000000000000000
[ 222.309311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 222.309311] CR2: 000000000040e7f0 CR3: 00000000a12d5000 CR4: 00000000000006e0
[ 222.309311] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 222.309311] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 222.309311] Process fio (pid: 4780, threadinfo ffff8800ba6e6000, task ffff8800b3d6bf00)
[ 222.309311] Stack:
[ 222.309311] 0000000000000001 ffff8800bab17a48 ffff8800bab17a48 ffff8800a13b7800
[ 222.309311] <0> ffff8800ba6e7a68 ffffffff8121da35 ffff880000000001 00ff8800ba5c5698
[ 222.309311] <0> ffff8800ba6e7a68 ffff8800a13b7800 0000000000000000 ffff8800bab17a48
[ 222.309311] Call Trace:
[ 222.309311] [<ffffffff8121da35>] __cfq_slice_expired+0x2af/0x3ec
[ 222.309311] [<ffffffff8121fd7b>] cfq_dispatch_requests+0x2c8/0x8e8
[ 222.309311] [<ffffffff8120f1cd>] ? spin_unlock_irqrestore+0xe/0x10
[ 222.309311] [<ffffffff8120fb1a>] ? blk_insert_cloned_request+0x70/0x7b
[ 222.309311] [<ffffffff81210461>] blk_peek_request+0x191/0x1a7
[ 222.309311] [<ffffffffa0002799>] dm_request_fn+0x38/0x14c [dm_mod]
[ 222.309311] [<ffffffff810ae61f>] ? sync_page_killable+0x0/0x35
[ 222.309311] [<ffffffff81210fd4>] __generic_unplug_device+0x32/0x37
[ 222.309311] [<ffffffff81211274>] generic_unplug_device+0x2e/0x3c
[ 222.309311] [<ffffffffa00011a6>] dm_unplug_all+0x42/0x5b [dm_mod]
[ 222.309311] [<ffffffff8120ca37>] blk_unplug+0x29/0x2d
[ 222.309311] [<ffffffff8120ca4d>] blk_backing_dev_unplug+0x12/0x14
[ 222.309311] [<ffffffff81109a7a>] block_sync_page+0x35/0x39
[ 222.309311] [<ffffffff810ae616>] sync_page+0x41/0x4a
[ 222.309311] [<ffffffff810ae62d>] sync_page_killable+0xe/0x35
[ 222.309311] [<ffffffff8158aa59>] __wait_on_bit_lock+0x46/0x8f
[ 222.309311] [<ffffffff810ae4f5>] __lock_page_killable+0x66/0x6d
[ 222.309311] [<ffffffff81056f9c>] ? wake_bit_function+0x0/0x33
[ 222.309311] [<ffffffff810ae528>] lock_page_killable+0x2c/0x2e
[ 222.309311] [<ffffffff810afbc5>] generic_file_aio_read+0x361/0x4f0
[ 222.309311] [<ffffffff810ea044>] do_sync_read+0xcb/0x108
[ 222.309311] [<ffffffff811e42f7>] ? security_file_permission+0x16/0x18
[ 222.309311] [<ffffffff810ea6ab>] vfs_read+0xab/0x108
[ 222.309311] [<ffffffff810ea7c8>] sys_read+0x4a/0x6e
[ 222.309311] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b
[ 222.309311] Code: 58 01 00 00 00 48 89 c6 75 0a 48 83 bb 60 01 00 00 00 74 09 48 8d bb a0 00 00 00 eb 35 41 fe cc 74 0d f6 83 c0 01 00 00 04 74 04 <0f> 0b eb fe 48 89 75 e8 e8 be e0 de ff 66 83 8b c0 01 00 00 04
[ 222.309311] RIP [<ffffffff8121ad88>] blkiocg_set_start_empty_time+0x50/0x83
[ 222.309311] RSP <ffff8800ba6e79f8>
[ 222.309311] ---[ end trace 32b4f71dffc15712 ]---
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Divyesh Shah <dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 8d2a91f8960b230b8bbcc4d97ed2015f5271c87d |
|
16-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Initialize blkg->stats_lock for the root cfqg too
This fixes the lockdep warning reported by Gui Jianfeng.
Signed-off-by: Divyesh Shah <dpshah@google.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 28baf44299e0480d66ebb3093de5d51deff04e9f |
|
14-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Fix compile errors
Fixes compile errors in blk-cgroup code for empty_time stat and a merge fix in
CFQ. The first error was when CONFIG_DEBUG_CFQ_IOSCHED is not set.
Signed-off-by: Divyesh Shah <dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| a11cdaa7af56423a921a8bdad8f5a5f4ddca918a |
|
13-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
block: Update to io-controller stats
Changelog from v1:
o Call blkiocg_update_idle_time_stats() at cfq_rq_enqueued() instead of at
dispatch time.
Changelog from original patchset: (in response to Vivek Goyal's comments)
o group blkiocg_update_blkio_group_dequeue_stats() with other DEBUG functions
o rename blkiocg_update_set_active_queue_stats() to
blkiocg_update_avg_queue_size_stats()
o s/request/io/ in blkiocg_update_request_add_stats() and
blkiocg_update_request_remove_stats()
o Call cfq_del_timer() at request dispatch() instead of
blkiocg_update_idle_time_stats()
Signed-off-by: Divyesh Shah<dpshah@google.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 34d0f179d6dd711d3fc13c0820a456c59aae8048 |
|
13-Apr-2010 |
Gui Jianfeng <guijianfeng@cn.fujitsu.com> |
io-controller: Add a new interface "weight_device" for IO-Controller
Currently, IO Controller makes use of blkio.weight to assign weight for
all devices. Here a new user interface "blkio.weight_device" is introduced to
assign different weights for different devices. blkio.weight becomes the
default value for devices which are not configured by "blkio.weight_device"
You can use the following format to assigned specific weight for a given
device:
#echo "major:minor weight" > blkio.weight_device
major:minor represents device number.
And you can remove weight for a given device as following:
#echo "major:minor 0" > blkio.weight_device
V1->V2 changes:
- use user interface "weight_device" instead of "policy" suggested by Vivek
- rename some struct suggested by Vivek
- rebase to 2.6-block "for-linus" branch
- remove an useless list_empty check pointed out by Li Zefan
- some trivial typo fix
V2->V3 changes:
- Move policy_*_node() functions up to get rid of forward declarations
- rename related functions by adding prefix "blkio_"
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 812df48d127365ffd0869aa139738f572a86759c |
|
09-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Add more debug-only per-cgroup stats
1) group_wait_time - This is the amount of time the cgroup had to wait to get a
timeslice for one of its queues from when it became busy, i.e., went from 0
to 1 request queued. This is different from the io_wait_time which is the
cumulative total of the amount of time spent by each IO in that cgroup waiting
in the scheduler queue. This stat is a great way to find out any jobs in the
fleet that are being starved or waiting for longer than what is expected (due
to an IO controller bug or any other issue).
2) empty_time - This is the amount of time a cgroup spends w/o any pending
requests. This stat is useful when a job does not seem to be able to use its
assigned disk share by helping check if that is happening due to an IO
controller bug or because the job is not submitting enough IOs.
3) idle_time - This is the amount of time spent by the IO scheduler idling
for a given cgroup in anticipation of a better request than the exising ones
from other queues/cgroups.
All these stats are recorded using start and stop events. When reading these
stats, we do not add the delta between the current time and the last start time
if we're between the start and stop events. We avoid doing this to make sure
that these numbers are always monotonically increasing when read. Since we're
using sched_clock() which may use the tsc as its source, it may induce some
inconsistency (due to tsc resync across cpus) if we included the current delta.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| cdc1184cf4a7bd99f5473a91244197accc49146b |
|
09-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Add io_queued and avg_queue_size stats
These stats are useful for getting a feel for the queue depth of the cgroup,
i.e., how filled up its queues are at a given instant and over the existence of
the cgroup. This ability is useful when debugging problems in the wild as it
helps understand the application's IO pattern w/o having to read through the
userspace code (coz its tedious or just not available) or w/o the ability
to run blktrace (since you may not have root access and/or not want to disturb
performance).
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 812d402648f4fc1ab1091b2172a46fc1b367c724 |
|
09-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Add io_merged stat
This includes both the number of bios merged into requests belonging to this
cgroup as well as the number of requests merged together.
In the past, we've observed different merging behavior across upstream kernels,
some by design some actual bugs. This stat helps a lot in debugging such
problems when applications report decreased throughput with a new kernel
version.
This needed adding an extra elevator function to capture bios being merged as I
did not want to pollute elevator code with blkiocg knowledge and hence needed
the accounting invocation to come from CFQ.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 84c124da9ff50bd71fab9c939ee5b7cd8bef2bd9 |
|
09-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Changes to IO controller additional stats patches
that include some minor fixes and addresses all comments.
Changelog: (most based on Vivek Goyal's comments)
o renamed blkiocg_reset_write to blkiocg_reset_stats
o more clarification in the documentation on io_service_time and io_wait_time
o Initialize blkg->stats_lock
o rename io_add_stat to blkio_add_stat and declare it static
o use bool for direction and sync
o derive direction and sync info from existing rq methods
o use 12 for major:minor string length
o define io_service_time better to cover the NCQ case
o add a separate reset_stats interface
o make the indexed stats a 2d array to simplify macro and function pointer code
o blkio.time now exports in jiffies as before
o Added stats description in patch description and
Documentation/cgroup/blkio-controller.txt
o Prefix all stats functions with blkio and make them static as applicable
o replace IO_TYPE_MAX with IO_TYPE_TOTAL
o Moved #define constant to top of blk-cgroup.c
o Pass dev_t around instead of char *
o Add note to documentation file about resetting stats
o use BLK_CGROUP_MODULE in addition to BLK_CGROUP config option in #ifdef
statements
o Avoid struct request specific knowledge in blk-cgroup. blk-cgroup.h now has
rq_direction() and rq_sync() functions which are used by CFQ and when using
io-controller at a higher level, bio_* functions can be added.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 9195291e5f05e01d67f9a09c756b8aca8f009089 |
|
02-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Increment the blkio cgroup stats for real now
We also add start_time_ns and io_start_time_ns fields to struct request
here to record the time when a request is created and when it is
dispatched to device. We use ns uints here as ms and jiffies are
not very useful for non-rotational media.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 303a3acb2362f16c7e7f4c53b40c2f4b396dc8d5 |
|
02-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Add io controller stats like
- io_service_time
- io_wait_time
- io_serviced
- io_service_bytes
These stats are accumulated per operation type helping us to distinguish between
read and write, and sync and async IO. This patch does not increment any of
these stats.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 9a0785b0da561e1e9c6617df85e93ae107a42f18 |
|
02-Apr-2010 |
Divyesh Shah <dpshah@google.com> |
blkio: Remove per-cfqq nr_sectors as we'll be passing
that info at request dispatch with other stats now. This patch removes the
existing support for accounting sectors for a blkio_group. This will be added
back differently in the next two patches.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 5a0e3ad6af8660be21ca98a971cd00f331318c05 |
|
24-Mar-2010 |
Tejun Heo <tj@kernel.org> |
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files. percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.
percpu.h -> slab.h dependency is about to be removed. Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability. As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.
http://userweb.kernel.org/~tj/misc/slabh-sweep.py
The script does the followings.
* Scan files for gfp and slab usages and update includes such that
only the necessary includes are there. ie. if only gfp is used,
gfp.h, if slab is used, slab.h.
* When the script inserts a new include, it looks at the include
blocks and try to put the new include such that its order conforms
to its surrounding. It's put in the include block which contains
core kernel includes, in the same order that the rest are ordered -
alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
doesn't seem to be any matching order.
* If the script can't find a place to put a new include (mostly
because the file doesn't have fitting include block), it prints out
an error message indicating which .h file needs to be added to the
file.
The conversion was done in the following steps.
1. The initial automatic conversion of all .c files updated slightly
over 4000 files, deleting around 700 includes and adding ~480 gfp.h
and ~3000 slab.h inclusions. The script emitted errors for ~400
files.
2. Each error was manually checked. Some didn't need the inclusion,
some needed manual addition while adding it to implementation .h or
embedding .c file was more appropriate for others. This step added
inclusions to around 150 files.
3. The script was run again and the output was compared to the edits
from #2 to make sure no file was left behind.
4. Several build tests were done and a couple of problems were fixed.
e.g. lib/decompress_*.c used malloc/free() wrappers around slab
APIs requiring slab.h to be added manually.
5. The script was run on all .h files but without automatically
editing them as sprinkling gfp.h and slab.h inclusions around .h
files could easily lead to inclusion dependency hell. Most gfp.h
inclusion directives were ignored as stuff from gfp.h was usually
wildly available and often used in preprocessor macros. Each
slab.h inclusion directive was examined and added manually as
necessary.
6. percpu.h was updated not to include slab.h.
7. Build test were done on the following configurations and failures
were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
distributed build env didn't work with gcov compiles) and a few
more options had to be turned off depending on archs to make things
build (like ipr on powerpc/64 which failed due to missing writeq).
* x86 and x86_64 UP and SMP allmodconfig and a custom test config.
* powerpc and powerpc64 SMP allmodconfig
* sparc and sparc64 SMP allmodconfig
* ia64 SMP allmodconfig
* s390 SMP allmodconfig
* alpha SMP allmodconfig
* um on x86_64 SMP allmodconfig
8. percpu.h modifications were reverted so that it could be applied as
a separate patch and serve as bisection point.
Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: Tejun Heo <tj@kernel.org>
Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
|
| 67523c48aa74d5637848edeccf285af1c60bf14a |
|
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>
|
| 024f9066165ffe9c8284431c78adcbcddd309831 |
|
26-Feb-2010 |
Gui Jianfeng <guijianfeng@cn.fujitsu.com> |
cfq: Remove useless css reference get
There's no need to take css reference here, for the caller
has already called rcu_read_lock() to prevent cgroup from
being removed.
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| bcf4dd43424cdfd8195f3955300a579fe58e9911 |
|
01-Feb-2010 |
Gui Jianfeng <guijianfeng@cn.fujitsu.com> |
blk-cgroup: Fix potential deadlock in blk-cgroup
I triggered a lockdep warning as following.
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.33-rc2 #1
-------------------------------------------------------
test_io_control/7357 is trying to acquire lock:
(blkio_list_lock){+.+...}, at: [<c053a990>] blkiocg_weight_write+0x82/0x9e
but task is already holding lock:
(&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&(&blkcg->lock)->rlock){......}:
[<c04583b7>] validate_chain+0x8bc/0xb9c
[<c0458dba>] __lock_acquire+0x723/0x789
[<c0458eb0>] lock_acquire+0x90/0xa7
[<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a
[<c053a4e1>] blkiocg_add_blkio_group+0x1a/0x6d
[<c053cac7>] cfq_get_queue+0x225/0x3de
[<c053eec2>] cfq_set_request+0x217/0x42d
[<c052c8a6>] elv_set_request+0x17/0x26
[<c0532a0f>] get_request+0x203/0x2c5
[<c0532ae9>] get_request_wait+0x18/0x10e
[<c0533470>] __make_request+0x2ba/0x375
[<c0531985>] generic_make_request+0x28d/0x30f
[<c0532da7>] submit_bio+0x8a/0x8f
[<c04d827a>] submit_bh+0xf0/0x10f
[<c04d91d2>] ll_rw_block+0xc0/0xf9
[<f86e9705>] ext3_find_entry+0x319/0x544 [ext3]
[<f86eae58>] ext3_lookup+0x2c/0xb9 [ext3]
[<c04c3e1b>] do_lookup+0xd3/0x172
[<c04c56c8>] link_path_walk+0x5fb/0x95c
[<c04c5a65>] path_walk+0x3c/0x81
[<c04c5b63>] do_path_lookup+0x21/0x8a
[<c04c66cc>] do_filp_open+0xf0/0x978
[<c04c0c7e>] open_exec+0x1b/0xb7
[<c04c1436>] do_execve+0xbb/0x266
[<c04081a9>] sys_execve+0x24/0x4a
[<c04028a2>] ptregs_execve+0x12/0x18
-> #1 (&(&q->__queue_lock)->rlock){..-.-.}:
[<c04583b7>] validate_chain+0x8bc/0xb9c
[<c0458dba>] __lock_acquire+0x723/0x789
[<c0458eb0>] lock_acquire+0x90/0xa7
[<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a
[<c053dd2a>] cfq_unlink_blkio_group+0x17/0x41
[<c053a6eb>] blkiocg_destroy+0x72/0xc7
[<c0467df0>] cgroup_diput+0x4a/0xb2
[<c04ca473>] dentry_iput+0x93/0xb7
[<c04ca4b3>] d_kill+0x1c/0x36
[<c04cb5c5>] dput+0xf5/0xfe
[<c04c6084>] do_rmdir+0x95/0xbe
[<c04c60ec>] sys_rmdir+0x10/0x12
[<c04027cc>] sysenter_do_call+0x12/0x32
-> #0 (blkio_list_lock){+.+...}:
[<c0458117>] validate_chain+0x61c/0xb9c
[<c0458dba>] __lock_acquire+0x723/0x789
[<c0458eb0>] lock_acquire+0x90/0xa7
[<c06929fd>] _raw_spin_lock+0x1e/0x4e
[<c053a990>] blkiocg_weight_write+0x82/0x9e
[<c0467f1e>] cgroup_file_write+0xc6/0x1c0
[<c04bd2f3>] vfs_write+0x8c/0x116
[<c04bd7c6>] sys_write+0x3b/0x60
[<c04027cc>] sysenter_do_call+0x12/0x32
other info that might help us debug this:
1 lock held by test_io_control/7357:
#0: (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e
stack backtrace:
Pid: 7357, comm: test_io_control Not tainted 2.6.33-rc2 #1
Call Trace:
[<c045754f>] print_circular_bug+0x91/0x9d
[<c0458117>] validate_chain+0x61c/0xb9c
[<c0458dba>] __lock_acquire+0x723/0x789
[<c0458eb0>] lock_acquire+0x90/0xa7
[<c053a990>] ? blkiocg_weight_write+0x82/0x9e
[<c06929fd>] _raw_spin_lock+0x1e/0x4e
[<c053a990>] ? blkiocg_weight_write+0x82/0x9e
[<c053a990>] blkiocg_weight_write+0x82/0x9e
[<c0467f1e>] cgroup_file_write+0xc6/0x1c0
[<c0454df5>] ? trace_hardirqs_off+0xb/0xd
[<c044d93a>] ? cpu_clock+0x2e/0x44
[<c050e6ec>] ? security_file_permission+0xf/0x11
[<c04bcdda>] ? rw_verify_area+0x8a/0xad
[<c0467e58>] ? cgroup_file_write+0x0/0x1c0
[<c04bd2f3>] vfs_write+0x8c/0x116
[<c04bd7c6>] sys_write+0x3b/0x60
[<c04027cc>] sysenter_do_call+0x12/0x32
To prevent deadlock, we should take locks as following sequence:
blkio_list_lock -> queue_lock -> blkcg_lock.
The following patch should fix this bug.
Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| accee7854b378a8ab5995d8f5dc5d8abc3b3d23a |
|
07-Dec-2009 |
Stephen Rothwell <sfr@canb.auug.org.au> |
block: include linux/err.h to use ERR_PTR
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 3e2520668970aab5a764044a298e987aafc1f63d |
|
04-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Implement dynamic io controlling policy registration
o One of the goals of block IO controller is that it should be able to
support mulitple io control policies, some of which be operational at
higher level in storage hierarchy.
o To begin with, we had one io controlling policy implemented by CFQ, and
I hard coded the CFQ functions called by blkio. This created issues when
CFQ is compiled as module.
o This patch implements a basic dynamic io controlling policy registration
functionality in blkio. This is similar to elevator functionality where
ioschedulers register the functions dynamically.
o Now in future, when more IO controlling policies are implemented, these
can dynakically register with block IO controller.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 9d6a986c0b276085f7944cd8ad65f4f82aff7536 |
|
04-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Export some symbols from blkio as its user CFQ can be a module
o blkio controller is inside the kernel and cfq makes use of interfaces
exported by blkio. CFQ can be a module too, hence export symbols used
by CFQ.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| f2eecb91522686edf8199947b77f435a4031d92f |
|
04-Dec-2009 |
Jens Axboe <jens.axboe@oracle.com> |
cfq-iosched: move IO controller declerations to a header file
They should not be declared inside some other file that's not related
to CFQ.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| f8d461d692c341add957fb973fb5ee1f62039dc7 |
|
03-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Propagate cgroup weight updation to cfq groups
o Propagate blkio cgroup weight updation to associated cfq groups.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 220841906fccafaf4094e87bdb6d252e20cf8c7c |
|
03-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Export disk time and sectors used by a group to user space
o Export disk time and sector used by a group to user space through cgroup
interface.
o Also export a "dequeue" interface to cgroup which keeps track of how many
a times a group was deleted from service tree. Helps in debugging.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 2868ef7b39490e6b41c2c61cd9a5cd891e778b54 |
|
03-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Some debugging aids for CFQ
o Some debugging aids for CFQ.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| b1c3576961847da26c91b1e97f226bb66be5fa3f |
|
03-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Take care of cgroup deletion and cfq group reference counting
o One can choose to change elevator or delete a cgroup. Implement group
reference counting so that both elevator exit and cgroup deletion can
take place gracefully.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Nauman Rafique <nauman@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|
| 31e4c28d95e64f2d5d3c497a3ecf37c62de635b4 |
|
03-Dec-2009 |
Vivek Goyal <vgoyal@redhat.com> |
blkio: Introduce blkio controller cgroup interface
o This is basic implementation of blkio controller cgroup interface. This is
the common interface visible to user space and should be used by different
IO control policies as we implement those.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
|