memcontrol.c revision ab936cbcd02072a34b60d268f94440fd5cf1970b
1/* memcontrol.c - Memory Controller 2 * 3 * Copyright IBM Corporation, 2007 4 * Author Balbir Singh <balbir@linux.vnet.ibm.com> 5 * 6 * Copyright 2007 OpenVZ SWsoft Inc 7 * Author: Pavel Emelianov <xemul@openvz.org> 8 * 9 * Memory thresholds 10 * Copyright (C) 2009 Nokia Corporation 11 * Author: Kirill A. Shutemov 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or 16 * (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 */ 23 24#include <linux/res_counter.h> 25#include <linux/memcontrol.h> 26#include <linux/cgroup.h> 27#include <linux/mm.h> 28#include <linux/hugetlb.h> 29#include <linux/pagemap.h> 30#include <linux/smp.h> 31#include <linux/page-flags.h> 32#include <linux/backing-dev.h> 33#include <linux/bit_spinlock.h> 34#include <linux/rcupdate.h> 35#include <linux/limits.h> 36#include <linux/export.h> 37#include <linux/mutex.h> 38#include <linux/rbtree.h> 39#include <linux/slab.h> 40#include <linux/swap.h> 41#include <linux/swapops.h> 42#include <linux/spinlock.h> 43#include <linux/eventfd.h> 44#include <linux/sort.h> 45#include <linux/fs.h> 46#include <linux/seq_file.h> 47#include <linux/vmalloc.h> 48#include <linux/mm_inline.h> 49#include <linux/page_cgroup.h> 50#include <linux/cpu.h> 51#include <linux/oom.h> 52#include "internal.h" 53#include <net/sock.h> 54#include <net/tcp_memcontrol.h> 55 56#include <asm/uaccess.h> 57 58#include <trace/events/vmscan.h> 59 60struct cgroup_subsys mem_cgroup_subsys __read_mostly; 61#define MEM_CGROUP_RECLAIM_RETRIES 5 62struct mem_cgroup *root_mem_cgroup __read_mostly; 63 64#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 65/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ 66int do_swap_account __read_mostly; 67 68/* for remember boot option*/ 69#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED 70static int really_do_swap_account __initdata = 1; 71#else 72static int really_do_swap_account __initdata = 0; 73#endif 74 75#else 76#define do_swap_account (0) 77#endif 78 79 80/* 81 * Statistics for memory cgroup. 82 */ 83enum mem_cgroup_stat_index { 84 /* 85 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. 86 */ 87 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ 88 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ 89 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ 90 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ 91 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */ 92 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */ 93 MEM_CGROUP_STAT_NSTATS, 94}; 95 96enum mem_cgroup_events_index { 97 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ 98 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ 99 MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */ 100 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */ 101 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */ 102 MEM_CGROUP_EVENTS_NSTATS, 103}; 104/* 105 * Per memcg event counter is incremented at every pagein/pageout. With THP, 106 * it will be incremated by the number of pages. This counter is used for 107 * for trigger some periodic events. This is straightforward and better 108 * than using jiffies etc. to handle periodic memcg event. 109 */ 110enum mem_cgroup_events_target { 111 MEM_CGROUP_TARGET_THRESH, 112 MEM_CGROUP_TARGET_SOFTLIMIT, 113 MEM_CGROUP_TARGET_NUMAINFO, 114 MEM_CGROUP_NTARGETS, 115}; 116#define THRESHOLDS_EVENTS_TARGET (128) 117#define SOFTLIMIT_EVENTS_TARGET (1024) 118#define NUMAINFO_EVENTS_TARGET (1024) 119 120struct mem_cgroup_stat_cpu { 121 long count[MEM_CGROUP_STAT_NSTATS]; 122 unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; 123 unsigned long targets[MEM_CGROUP_NTARGETS]; 124}; 125 126/* 127 * per-zone information in memory controller. 128 */ 129struct mem_cgroup_per_zone { 130 /* 131 * spin_lock to protect the per cgroup LRU 132 */ 133 struct list_head lists[NR_LRU_LISTS]; 134 unsigned long count[NR_LRU_LISTS]; 135 136 struct zone_reclaim_stat reclaim_stat; 137 struct rb_node tree_node; /* RB tree node */ 138 unsigned long long usage_in_excess;/* Set to the value by which */ 139 /* the soft limit is exceeded*/ 140 bool on_tree; 141 struct mem_cgroup *mem; /* Back pointer, we cannot */ 142 /* use container_of */ 143}; 144/* Macro for accessing counter */ 145#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) 146 147struct mem_cgroup_per_node { 148 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; 149}; 150 151struct mem_cgroup_lru_info { 152 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; 153}; 154 155/* 156 * Cgroups above their limits are maintained in a RB-Tree, independent of 157 * their hierarchy representation 158 */ 159 160struct mem_cgroup_tree_per_zone { 161 struct rb_root rb_root; 162 spinlock_t lock; 163}; 164 165struct mem_cgroup_tree_per_node { 166 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; 167}; 168 169struct mem_cgroup_tree { 170 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; 171}; 172 173static struct mem_cgroup_tree soft_limit_tree __read_mostly; 174 175struct mem_cgroup_threshold { 176 struct eventfd_ctx *eventfd; 177 u64 threshold; 178}; 179 180/* For threshold */ 181struct mem_cgroup_threshold_ary { 182 /* An array index points to threshold just below usage. */ 183 int current_threshold; 184 /* Size of entries[] */ 185 unsigned int size; 186 /* Array of thresholds */ 187 struct mem_cgroup_threshold entries[0]; 188}; 189 190struct mem_cgroup_thresholds { 191 /* Primary thresholds array */ 192 struct mem_cgroup_threshold_ary *primary; 193 /* 194 * Spare threshold array. 195 * This is needed to make mem_cgroup_unregister_event() "never fail". 196 * It must be able to store at least primary->size - 1 entries. 197 */ 198 struct mem_cgroup_threshold_ary *spare; 199}; 200 201/* for OOM */ 202struct mem_cgroup_eventfd_list { 203 struct list_head list; 204 struct eventfd_ctx *eventfd; 205}; 206 207static void mem_cgroup_threshold(struct mem_cgroup *memcg); 208static void mem_cgroup_oom_notify(struct mem_cgroup *memcg); 209 210/* 211 * The memory controller data structure. The memory controller controls both 212 * page cache and RSS per cgroup. We would eventually like to provide 213 * statistics based on the statistics developed by Rik Van Riel for clock-pro, 214 * to help the administrator determine what knobs to tune. 215 * 216 * TODO: Add a water mark for the memory controller. Reclaim will begin when 217 * we hit the water mark. May be even add a low water mark, such that 218 * no reclaim occurs from a cgroup at it's low water mark, this is 219 * a feature that will be implemented much later in the future. 220 */ 221struct mem_cgroup { 222 struct cgroup_subsys_state css; 223 /* 224 * the counter to account for memory usage 225 */ 226 struct res_counter res; 227 /* 228 * the counter to account for mem+swap usage. 229 */ 230 struct res_counter memsw; 231 /* 232 * Per cgroup active and inactive list, similar to the 233 * per zone LRU lists. 234 */ 235 struct mem_cgroup_lru_info info; 236 /* 237 * While reclaiming in a hierarchy, we cache the last child we 238 * reclaimed from. 239 */ 240 int last_scanned_child; 241 int last_scanned_node; 242#if MAX_NUMNODES > 1 243 nodemask_t scan_nodes; 244 atomic_t numainfo_events; 245 atomic_t numainfo_updating; 246#endif 247 /* 248 * Should the accounting and control be hierarchical, per subtree? 249 */ 250 bool use_hierarchy; 251 252 bool oom_lock; 253 atomic_t under_oom; 254 255 atomic_t refcnt; 256 257 int swappiness; 258 /* OOM-Killer disable */ 259 int oom_kill_disable; 260 261 /* set when res.limit == memsw.limit */ 262 bool memsw_is_minimum; 263 264 /* protect arrays of thresholds */ 265 struct mutex thresholds_lock; 266 267 /* thresholds for memory usage. RCU-protected */ 268 struct mem_cgroup_thresholds thresholds; 269 270 /* thresholds for mem+swap usage. RCU-protected */ 271 struct mem_cgroup_thresholds memsw_thresholds; 272 273 /* For oom notifier event fd */ 274 struct list_head oom_notify; 275 276 /* 277 * Should we move charges of a task when a task is moved into this 278 * mem_cgroup ? And what type of charges should we move ? 279 */ 280 unsigned long move_charge_at_immigrate; 281 /* 282 * percpu counter. 283 */ 284 struct mem_cgroup_stat_cpu *stat; 285 /* 286 * used when a cpu is offlined or other synchronizations 287 * See mem_cgroup_read_stat(). 288 */ 289 struct mem_cgroup_stat_cpu nocpu_base; 290 spinlock_t pcp_counter_lock; 291 292#ifdef CONFIG_INET 293 struct tcp_memcontrol tcp_mem; 294#endif 295}; 296 297/* Stuffs for move charges at task migration. */ 298/* 299 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a 300 * left-shifted bitmap of these types. 301 */ 302enum move_type { 303 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ 304 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ 305 NR_MOVE_TYPE, 306}; 307 308/* "mc" and its members are protected by cgroup_mutex */ 309static struct move_charge_struct { 310 spinlock_t lock; /* for from, to */ 311 struct mem_cgroup *from; 312 struct mem_cgroup *to; 313 unsigned long precharge; 314 unsigned long moved_charge; 315 unsigned long moved_swap; 316 struct task_struct *moving_task; /* a task moving charges */ 317 wait_queue_head_t waitq; /* a waitq for other context */ 318} mc = { 319 .lock = __SPIN_LOCK_UNLOCKED(mc.lock), 320 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), 321}; 322 323static bool move_anon(void) 324{ 325 return test_bit(MOVE_CHARGE_TYPE_ANON, 326 &mc.to->move_charge_at_immigrate); 327} 328 329static bool move_file(void) 330{ 331 return test_bit(MOVE_CHARGE_TYPE_FILE, 332 &mc.to->move_charge_at_immigrate); 333} 334 335/* 336 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft 337 * limit reclaim to prevent infinite loops, if they ever occur. 338 */ 339#define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) 340#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) 341 342enum charge_type { 343 MEM_CGROUP_CHARGE_TYPE_CACHE = 0, 344 MEM_CGROUP_CHARGE_TYPE_MAPPED, 345 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ 346 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ 347 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ 348 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ 349 NR_CHARGE_TYPE, 350}; 351 352/* for encoding cft->private value on file */ 353#define _MEM (0) 354#define _MEMSWAP (1) 355#define _OOM_TYPE (2) 356#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) 357#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) 358#define MEMFILE_ATTR(val) ((val) & 0xffff) 359/* Used for OOM nofiier */ 360#define OOM_CONTROL (0) 361 362/* 363 * Reclaim flags for mem_cgroup_hierarchical_reclaim 364 */ 365#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 366#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) 367#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 368#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) 369#define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2 370#define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT) 371 372static void mem_cgroup_get(struct mem_cgroup *memcg); 373static void mem_cgroup_put(struct mem_cgroup *memcg); 374 375/* Writing them here to avoid exposing memcg's inner layout */ 376#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM 377#ifdef CONFIG_INET 378#include <net/sock.h> 379#include <net/ip.h> 380 381static bool mem_cgroup_is_root(struct mem_cgroup *memcg); 382void sock_update_memcg(struct sock *sk) 383{ 384 if (static_branch(&memcg_socket_limit_enabled)) { 385 struct mem_cgroup *memcg; 386 387 BUG_ON(!sk->sk_prot->proto_cgroup); 388 389 /* Socket cloning can throw us here with sk_cgrp already 390 * filled. It won't however, necessarily happen from 391 * process context. So the test for root memcg given 392 * the current task's memcg won't help us in this case. 393 * 394 * Respecting the original socket's memcg is a better 395 * decision in this case. 396 */ 397 if (sk->sk_cgrp) { 398 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg)); 399 mem_cgroup_get(sk->sk_cgrp->memcg); 400 return; 401 } 402 403 rcu_read_lock(); 404 memcg = mem_cgroup_from_task(current); 405 if (!mem_cgroup_is_root(memcg)) { 406 mem_cgroup_get(memcg); 407 sk->sk_cgrp = sk->sk_prot->proto_cgroup(memcg); 408 } 409 rcu_read_unlock(); 410 } 411} 412EXPORT_SYMBOL(sock_update_memcg); 413 414void sock_release_memcg(struct sock *sk) 415{ 416 if (static_branch(&memcg_socket_limit_enabled) && sk->sk_cgrp) { 417 struct mem_cgroup *memcg; 418 WARN_ON(!sk->sk_cgrp->memcg); 419 memcg = sk->sk_cgrp->memcg; 420 mem_cgroup_put(memcg); 421 } 422} 423 424struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg) 425{ 426 if (!memcg || mem_cgroup_is_root(memcg)) 427 return NULL; 428 429 return &memcg->tcp_mem.cg_proto; 430} 431EXPORT_SYMBOL(tcp_proto_cgroup); 432#endif /* CONFIG_INET */ 433#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */ 434 435static void drain_all_stock_async(struct mem_cgroup *memcg); 436 437static struct mem_cgroup_per_zone * 438mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid) 439{ 440 return &memcg->info.nodeinfo[nid]->zoneinfo[zid]; 441} 442 443struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg) 444{ 445 return &memcg->css; 446} 447 448static struct mem_cgroup_per_zone * 449page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page) 450{ 451 int nid = page_to_nid(page); 452 int zid = page_zonenum(page); 453 454 return mem_cgroup_zoneinfo(memcg, nid, zid); 455} 456 457static struct mem_cgroup_tree_per_zone * 458soft_limit_tree_node_zone(int nid, int zid) 459{ 460 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 461} 462 463static struct mem_cgroup_tree_per_zone * 464soft_limit_tree_from_page(struct page *page) 465{ 466 int nid = page_to_nid(page); 467 int zid = page_zonenum(page); 468 469 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 470} 471 472static void 473__mem_cgroup_insert_exceeded(struct mem_cgroup *memcg, 474 struct mem_cgroup_per_zone *mz, 475 struct mem_cgroup_tree_per_zone *mctz, 476 unsigned long long new_usage_in_excess) 477{ 478 struct rb_node **p = &mctz->rb_root.rb_node; 479 struct rb_node *parent = NULL; 480 struct mem_cgroup_per_zone *mz_node; 481 482 if (mz->on_tree) 483 return; 484 485 mz->usage_in_excess = new_usage_in_excess; 486 if (!mz->usage_in_excess) 487 return; 488 while (*p) { 489 parent = *p; 490 mz_node = rb_entry(parent, struct mem_cgroup_per_zone, 491 tree_node); 492 if (mz->usage_in_excess < mz_node->usage_in_excess) 493 p = &(*p)->rb_left; 494 /* 495 * We can't avoid mem cgroups that are over their soft 496 * limit by the same amount 497 */ 498 else if (mz->usage_in_excess >= mz_node->usage_in_excess) 499 p = &(*p)->rb_right; 500 } 501 rb_link_node(&mz->tree_node, parent, p); 502 rb_insert_color(&mz->tree_node, &mctz->rb_root); 503 mz->on_tree = true; 504} 505 506static void 507__mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, 508 struct mem_cgroup_per_zone *mz, 509 struct mem_cgroup_tree_per_zone *mctz) 510{ 511 if (!mz->on_tree) 512 return; 513 rb_erase(&mz->tree_node, &mctz->rb_root); 514 mz->on_tree = false; 515} 516 517static void 518mem_cgroup_remove_exceeded(struct mem_cgroup *memcg, 519 struct mem_cgroup_per_zone *mz, 520 struct mem_cgroup_tree_per_zone *mctz) 521{ 522 spin_lock(&mctz->lock); 523 __mem_cgroup_remove_exceeded(memcg, mz, mctz); 524 spin_unlock(&mctz->lock); 525} 526 527 528static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page) 529{ 530 unsigned long long excess; 531 struct mem_cgroup_per_zone *mz; 532 struct mem_cgroup_tree_per_zone *mctz; 533 int nid = page_to_nid(page); 534 int zid = page_zonenum(page); 535 mctz = soft_limit_tree_from_page(page); 536 537 /* 538 * Necessary to update all ancestors when hierarchy is used. 539 * because their event counter is not touched. 540 */ 541 for (; memcg; memcg = parent_mem_cgroup(memcg)) { 542 mz = mem_cgroup_zoneinfo(memcg, nid, zid); 543 excess = res_counter_soft_limit_excess(&memcg->res); 544 /* 545 * We have to update the tree if mz is on RB-tree or 546 * mem is over its softlimit. 547 */ 548 if (excess || mz->on_tree) { 549 spin_lock(&mctz->lock); 550 /* if on-tree, remove it */ 551 if (mz->on_tree) 552 __mem_cgroup_remove_exceeded(memcg, mz, mctz); 553 /* 554 * Insert again. mz->usage_in_excess will be updated. 555 * If excess is 0, no tree ops. 556 */ 557 __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess); 558 spin_unlock(&mctz->lock); 559 } 560 } 561} 562 563static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg) 564{ 565 int node, zone; 566 struct mem_cgroup_per_zone *mz; 567 struct mem_cgroup_tree_per_zone *mctz; 568 569 for_each_node_state(node, N_POSSIBLE) { 570 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 571 mz = mem_cgroup_zoneinfo(memcg, node, zone); 572 mctz = soft_limit_tree_node_zone(node, zone); 573 mem_cgroup_remove_exceeded(memcg, mz, mctz); 574 } 575 } 576} 577 578static struct mem_cgroup_per_zone * 579__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 580{ 581 struct rb_node *rightmost = NULL; 582 struct mem_cgroup_per_zone *mz; 583 584retry: 585 mz = NULL; 586 rightmost = rb_last(&mctz->rb_root); 587 if (!rightmost) 588 goto done; /* Nothing to reclaim from */ 589 590 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); 591 /* 592 * Remove the node now but someone else can add it back, 593 * we will to add it back at the end of reclaim to its correct 594 * position in the tree. 595 */ 596 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 597 if (!res_counter_soft_limit_excess(&mz->mem->res) || 598 !css_tryget(&mz->mem->css)) 599 goto retry; 600done: 601 return mz; 602} 603 604static struct mem_cgroup_per_zone * 605mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 606{ 607 struct mem_cgroup_per_zone *mz; 608 609 spin_lock(&mctz->lock); 610 mz = __mem_cgroup_largest_soft_limit_node(mctz); 611 spin_unlock(&mctz->lock); 612 return mz; 613} 614 615/* 616 * Implementation Note: reading percpu statistics for memcg. 617 * 618 * Both of vmstat[] and percpu_counter has threshold and do periodic 619 * synchronization to implement "quick" read. There are trade-off between 620 * reading cost and precision of value. Then, we may have a chance to implement 621 * a periodic synchronizion of counter in memcg's counter. 622 * 623 * But this _read() function is used for user interface now. The user accounts 624 * memory usage by memory cgroup and he _always_ requires exact value because 625 * he accounts memory. Even if we provide quick-and-fuzzy read, we always 626 * have to visit all online cpus and make sum. So, for now, unnecessary 627 * synchronization is not implemented. (just implemented for cpu hotplug) 628 * 629 * If there are kernel internal actions which can make use of some not-exact 630 * value, and reading all cpu value can be performance bottleneck in some 631 * common workload, threashold and synchonization as vmstat[] should be 632 * implemented. 633 */ 634static long mem_cgroup_read_stat(struct mem_cgroup *memcg, 635 enum mem_cgroup_stat_index idx) 636{ 637 long val = 0; 638 int cpu; 639 640 get_online_cpus(); 641 for_each_online_cpu(cpu) 642 val += per_cpu(memcg->stat->count[idx], cpu); 643#ifdef CONFIG_HOTPLUG_CPU 644 spin_lock(&memcg->pcp_counter_lock); 645 val += memcg->nocpu_base.count[idx]; 646 spin_unlock(&memcg->pcp_counter_lock); 647#endif 648 put_online_cpus(); 649 return val; 650} 651 652static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg, 653 bool charge) 654{ 655 int val = (charge) ? 1 : -1; 656 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); 657} 658 659void mem_cgroup_pgfault(struct mem_cgroup *memcg, int val) 660{ 661 this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT], val); 662} 663 664void mem_cgroup_pgmajfault(struct mem_cgroup *memcg, int val) 665{ 666 this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT], val); 667} 668 669static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg, 670 enum mem_cgroup_events_index idx) 671{ 672 unsigned long val = 0; 673 int cpu; 674 675 for_each_online_cpu(cpu) 676 val += per_cpu(memcg->stat->events[idx], cpu); 677#ifdef CONFIG_HOTPLUG_CPU 678 spin_lock(&memcg->pcp_counter_lock); 679 val += memcg->nocpu_base.events[idx]; 680 spin_unlock(&memcg->pcp_counter_lock); 681#endif 682 return val; 683} 684 685static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg, 686 bool file, int nr_pages) 687{ 688 preempt_disable(); 689 690 if (file) 691 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE], 692 nr_pages); 693 else 694 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS], 695 nr_pages); 696 697 /* pagein of a big page is an event. So, ignore page size */ 698 if (nr_pages > 0) 699 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); 700 else { 701 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); 702 nr_pages = -nr_pages; /* for event */ 703 } 704 705 __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages); 706 707 preempt_enable(); 708} 709 710unsigned long 711mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid, 712 unsigned int lru_mask) 713{ 714 struct mem_cgroup_per_zone *mz; 715 enum lru_list l; 716 unsigned long ret = 0; 717 718 mz = mem_cgroup_zoneinfo(memcg, nid, zid); 719 720 for_each_lru(l) { 721 if (BIT(l) & lru_mask) 722 ret += MEM_CGROUP_ZSTAT(mz, l); 723 } 724 return ret; 725} 726 727static unsigned long 728mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, 729 int nid, unsigned int lru_mask) 730{ 731 u64 total = 0; 732 int zid; 733 734 for (zid = 0; zid < MAX_NR_ZONES; zid++) 735 total += mem_cgroup_zone_nr_lru_pages(memcg, 736 nid, zid, lru_mask); 737 738 return total; 739} 740 741static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, 742 unsigned int lru_mask) 743{ 744 int nid; 745 u64 total = 0; 746 747 for_each_node_state(nid, N_HIGH_MEMORY) 748 total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask); 749 return total; 750} 751 752static bool __memcg_event_check(struct mem_cgroup *memcg, int target) 753{ 754 unsigned long val, next; 755 756 val = __this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]); 757 next = __this_cpu_read(memcg->stat->targets[target]); 758 /* from time_after() in jiffies.h */ 759 return ((long)next - (long)val < 0); 760} 761 762static void __mem_cgroup_target_update(struct mem_cgroup *memcg, int target) 763{ 764 unsigned long val, next; 765 766 val = __this_cpu_read(memcg->stat->events[MEM_CGROUP_EVENTS_COUNT]); 767 768 switch (target) { 769 case MEM_CGROUP_TARGET_THRESH: 770 next = val + THRESHOLDS_EVENTS_TARGET; 771 break; 772 case MEM_CGROUP_TARGET_SOFTLIMIT: 773 next = val + SOFTLIMIT_EVENTS_TARGET; 774 break; 775 case MEM_CGROUP_TARGET_NUMAINFO: 776 next = val + NUMAINFO_EVENTS_TARGET; 777 break; 778 default: 779 return; 780 } 781 782 __this_cpu_write(memcg->stat->targets[target], next); 783} 784 785/* 786 * Check events in order. 787 * 788 */ 789static void memcg_check_events(struct mem_cgroup *memcg, struct page *page) 790{ 791 preempt_disable(); 792 /* threshold event is triggered in finer grain than soft limit */ 793 if (unlikely(__memcg_event_check(memcg, MEM_CGROUP_TARGET_THRESH))) { 794 mem_cgroup_threshold(memcg); 795 __mem_cgroup_target_update(memcg, MEM_CGROUP_TARGET_THRESH); 796 if (unlikely(__memcg_event_check(memcg, 797 MEM_CGROUP_TARGET_SOFTLIMIT))) { 798 mem_cgroup_update_tree(memcg, page); 799 __mem_cgroup_target_update(memcg, 800 MEM_CGROUP_TARGET_SOFTLIMIT); 801 } 802#if MAX_NUMNODES > 1 803 if (unlikely(__memcg_event_check(memcg, 804 MEM_CGROUP_TARGET_NUMAINFO))) { 805 atomic_inc(&memcg->numainfo_events); 806 __mem_cgroup_target_update(memcg, 807 MEM_CGROUP_TARGET_NUMAINFO); 808 } 809#endif 810 } 811 preempt_enable(); 812} 813 814struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) 815{ 816 return container_of(cgroup_subsys_state(cont, 817 mem_cgroup_subsys_id), struct mem_cgroup, 818 css); 819} 820 821struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 822{ 823 /* 824 * mm_update_next_owner() may clear mm->owner to NULL 825 * if it races with swapoff, page migration, etc. 826 * So this can be called with p == NULL. 827 */ 828 if (unlikely(!p)) 829 return NULL; 830 831 return container_of(task_subsys_state(p, mem_cgroup_subsys_id), 832 struct mem_cgroup, css); 833} 834 835struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 836{ 837 struct mem_cgroup *memcg = NULL; 838 839 if (!mm) 840 return NULL; 841 /* 842 * Because we have no locks, mm->owner's may be being moved to other 843 * cgroup. We use css_tryget() here even if this looks 844 * pessimistic (rather than adding locks here). 845 */ 846 rcu_read_lock(); 847 do { 848 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); 849 if (unlikely(!memcg)) 850 break; 851 } while (!css_tryget(&memcg->css)); 852 rcu_read_unlock(); 853 return memcg; 854} 855 856/* The caller has to guarantee "mem" exists before calling this */ 857static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *memcg) 858{ 859 struct cgroup_subsys_state *css; 860 int found; 861 862 if (!memcg) /* ROOT cgroup has the smallest ID */ 863 return root_mem_cgroup; /*css_put/get against root is ignored*/ 864 if (!memcg->use_hierarchy) { 865 if (css_tryget(&memcg->css)) 866 return memcg; 867 return NULL; 868 } 869 rcu_read_lock(); 870 /* 871 * searching a memory cgroup which has the smallest ID under given 872 * ROOT cgroup. (ID >= 1) 873 */ 874 css = css_get_next(&mem_cgroup_subsys, 1, &memcg->css, &found); 875 if (css && css_tryget(css)) 876 memcg = container_of(css, struct mem_cgroup, css); 877 else 878 memcg = NULL; 879 rcu_read_unlock(); 880 return memcg; 881} 882 883static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter, 884 struct mem_cgroup *root, 885 bool cond) 886{ 887 int nextid = css_id(&iter->css) + 1; 888 int found; 889 int hierarchy_used; 890 struct cgroup_subsys_state *css; 891 892 hierarchy_used = iter->use_hierarchy; 893 894 css_put(&iter->css); 895 /* If no ROOT, walk all, ignore hierarchy */ 896 if (!cond || (root && !hierarchy_used)) 897 return NULL; 898 899 if (!root) 900 root = root_mem_cgroup; 901 902 do { 903 iter = NULL; 904 rcu_read_lock(); 905 906 css = css_get_next(&mem_cgroup_subsys, nextid, 907 &root->css, &found); 908 if (css && css_tryget(css)) 909 iter = container_of(css, struct mem_cgroup, css); 910 rcu_read_unlock(); 911 /* If css is NULL, no more cgroups will be found */ 912 nextid = found + 1; 913 } while (css && !iter); 914 915 return iter; 916} 917/* 918 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please 919 * be careful that "break" loop is not allowed. We have reference count. 920 * Instead of that modify "cond" to be false and "continue" to exit the loop. 921 */ 922#define for_each_mem_cgroup_tree_cond(iter, root, cond) \ 923 for (iter = mem_cgroup_start_loop(root);\ 924 iter != NULL;\ 925 iter = mem_cgroup_get_next(iter, root, cond)) 926 927#define for_each_mem_cgroup_tree(iter, root) \ 928 for_each_mem_cgroup_tree_cond(iter, root, true) 929 930#define for_each_mem_cgroup_all(iter) \ 931 for_each_mem_cgroup_tree_cond(iter, NULL, true) 932 933 934static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) 935{ 936 return (memcg == root_mem_cgroup); 937} 938 939void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx) 940{ 941 struct mem_cgroup *memcg; 942 943 if (!mm) 944 return; 945 946 rcu_read_lock(); 947 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); 948 if (unlikely(!memcg)) 949 goto out; 950 951 switch (idx) { 952 case PGMAJFAULT: 953 mem_cgroup_pgmajfault(memcg, 1); 954 break; 955 case PGFAULT: 956 mem_cgroup_pgfault(memcg, 1); 957 break; 958 default: 959 BUG(); 960 } 961out: 962 rcu_read_unlock(); 963} 964EXPORT_SYMBOL(mem_cgroup_count_vm_event); 965 966/* 967 * Following LRU functions are allowed to be used without PCG_LOCK. 968 * Operations are called by routine of global LRU independently from memcg. 969 * What we have to take care of here is validness of pc->mem_cgroup. 970 * 971 * Changes to pc->mem_cgroup happens when 972 * 1. charge 973 * 2. moving account 974 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. 975 * It is added to LRU before charge. 976 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. 977 * When moving account, the page is not on LRU. It's isolated. 978 */ 979 980void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) 981{ 982 struct page_cgroup *pc; 983 struct mem_cgroup_per_zone *mz; 984 985 if (mem_cgroup_disabled()) 986 return; 987 pc = lookup_page_cgroup(page); 988 /* can happen while we handle swapcache. */ 989 if (!TestClearPageCgroupAcctLRU(pc)) 990 return; 991 VM_BUG_ON(!pc->mem_cgroup); 992 /* 993 * We don't check PCG_USED bit. It's cleared when the "page" is finally 994 * removed from global LRU. 995 */ 996 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 997 /* huge page split is done under lru_lock. so, we have no races. */ 998 MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); 999 if (mem_cgroup_is_root(pc->mem_cgroup)) 1000 return; 1001 VM_BUG_ON(list_empty(&pc->lru)); 1002 list_del_init(&pc->lru); 1003} 1004 1005void mem_cgroup_del_lru(struct page *page) 1006{ 1007 mem_cgroup_del_lru_list(page, page_lru(page)); 1008} 1009 1010/* 1011 * Writeback is about to end against a page which has been marked for immediate 1012 * reclaim. If it still appears to be reclaimable, move it to the tail of the 1013 * inactive list. 1014 */ 1015void mem_cgroup_rotate_reclaimable_page(struct page *page) 1016{ 1017 struct mem_cgroup_per_zone *mz; 1018 struct page_cgroup *pc; 1019 enum lru_list lru = page_lru(page); 1020 1021 if (mem_cgroup_disabled()) 1022 return; 1023 1024 pc = lookup_page_cgroup(page); 1025 /* unused or root page is not rotated. */ 1026 if (!PageCgroupUsed(pc)) 1027 return; 1028 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 1029 smp_rmb(); 1030 if (mem_cgroup_is_root(pc->mem_cgroup)) 1031 return; 1032 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 1033 list_move_tail(&pc->lru, &mz->lists[lru]); 1034} 1035 1036void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) 1037{ 1038 struct mem_cgroup_per_zone *mz; 1039 struct page_cgroup *pc; 1040 1041 if (mem_cgroup_disabled()) 1042 return; 1043 1044 pc = lookup_page_cgroup(page); 1045 /* unused or root page is not rotated. */ 1046 if (!PageCgroupUsed(pc)) 1047 return; 1048 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 1049 smp_rmb(); 1050 if (mem_cgroup_is_root(pc->mem_cgroup)) 1051 return; 1052 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 1053 list_move(&pc->lru, &mz->lists[lru]); 1054} 1055 1056void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) 1057{ 1058 struct page_cgroup *pc; 1059 struct mem_cgroup_per_zone *mz; 1060 1061 if (mem_cgroup_disabled()) 1062 return; 1063 pc = lookup_page_cgroup(page); 1064 VM_BUG_ON(PageCgroupAcctLRU(pc)); 1065 /* 1066 * putback: charge: 1067 * SetPageLRU SetPageCgroupUsed 1068 * smp_mb smp_mb 1069 * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU 1070 * 1071 * Ensure that one of the two sides adds the page to the memcg 1072 * LRU during a race. 1073 */ 1074 smp_mb(); 1075 if (!PageCgroupUsed(pc)) 1076 return; 1077 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 1078 smp_rmb(); 1079 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 1080 /* huge page split is done under lru_lock. so, we have no races. */ 1081 MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); 1082 SetPageCgroupAcctLRU(pc); 1083 if (mem_cgroup_is_root(pc->mem_cgroup)) 1084 return; 1085 list_add(&pc->lru, &mz->lists[lru]); 1086} 1087 1088/* 1089 * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed 1090 * while it's linked to lru because the page may be reused after it's fully 1091 * uncharged. To handle that, unlink page_cgroup from LRU when charge it again. 1092 * It's done under lock_page and expected that zone->lru_lock isnever held. 1093 */ 1094static void mem_cgroup_lru_del_before_commit(struct page *page) 1095{ 1096 unsigned long flags; 1097 struct zone *zone = page_zone(page); 1098 struct page_cgroup *pc = lookup_page_cgroup(page); 1099 1100 /* 1101 * Doing this check without taking ->lru_lock seems wrong but this 1102 * is safe. Because if page_cgroup's USED bit is unset, the page 1103 * will not be added to any memcg's LRU. If page_cgroup's USED bit is 1104 * set, the commit after this will fail, anyway. 1105 * This all charge/uncharge is done under some mutual execustion. 1106 * So, we don't need to taking care of changes in USED bit. 1107 */ 1108 if (likely(!PageLRU(page))) 1109 return; 1110 1111 spin_lock_irqsave(&zone->lru_lock, flags); 1112 /* 1113 * Forget old LRU when this page_cgroup is *not* used. This Used bit 1114 * is guarded by lock_page() because the page is SwapCache. 1115 */ 1116 if (!PageCgroupUsed(pc)) 1117 mem_cgroup_del_lru_list(page, page_lru(page)); 1118 spin_unlock_irqrestore(&zone->lru_lock, flags); 1119} 1120 1121static void mem_cgroup_lru_add_after_commit(struct page *page) 1122{ 1123 unsigned long flags; 1124 struct zone *zone = page_zone(page); 1125 struct page_cgroup *pc = lookup_page_cgroup(page); 1126 /* 1127 * putback: charge: 1128 * SetPageLRU SetPageCgroupUsed 1129 * smp_mb smp_mb 1130 * PageCgroupUsed && add to memcg LRU PageLRU && add to memcg LRU 1131 * 1132 * Ensure that one of the two sides adds the page to the memcg 1133 * LRU during a race. 1134 */ 1135 smp_mb(); 1136 /* taking care of that the page is added to LRU while we commit it */ 1137 if (likely(!PageLRU(page))) 1138 return; 1139 spin_lock_irqsave(&zone->lru_lock, flags); 1140 /* link when the page is linked to LRU but page_cgroup isn't */ 1141 if (PageLRU(page) && !PageCgroupAcctLRU(pc)) 1142 mem_cgroup_add_lru_list(page, page_lru(page)); 1143 spin_unlock_irqrestore(&zone->lru_lock, flags); 1144} 1145 1146 1147void mem_cgroup_move_lists(struct page *page, 1148 enum lru_list from, enum lru_list to) 1149{ 1150 if (mem_cgroup_disabled()) 1151 return; 1152 mem_cgroup_del_lru_list(page, from); 1153 mem_cgroup_add_lru_list(page, to); 1154} 1155 1156/* 1157 * Checks whether given mem is same or in the root_mem_cgroup's 1158 * hierarchy subtree 1159 */ 1160static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg, 1161 struct mem_cgroup *memcg) 1162{ 1163 if (root_memcg != memcg) { 1164 return (root_memcg->use_hierarchy && 1165 css_is_ancestor(&memcg->css, &root_memcg->css)); 1166 } 1167 1168 return true; 1169} 1170 1171int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg) 1172{ 1173 int ret; 1174 struct mem_cgroup *curr = NULL; 1175 struct task_struct *p; 1176 1177 p = find_lock_task_mm(task); 1178 if (!p) 1179 return 0; 1180 curr = try_get_mem_cgroup_from_mm(p->mm); 1181 task_unlock(p); 1182 if (!curr) 1183 return 0; 1184 /* 1185 * We should check use_hierarchy of "memcg" not "curr". Because checking 1186 * use_hierarchy of "curr" here make this function true if hierarchy is 1187 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup* 1188 * hierarchy(even if use_hierarchy is disabled in "memcg"). 1189 */ 1190 ret = mem_cgroup_same_or_subtree(memcg, curr); 1191 css_put(&curr->css); 1192 return ret; 1193} 1194 1195int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone) 1196{ 1197 unsigned long inactive_ratio; 1198 int nid = zone_to_nid(zone); 1199 int zid = zone_idx(zone); 1200 unsigned long inactive; 1201 unsigned long active; 1202 unsigned long gb; 1203 1204 inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, 1205 BIT(LRU_INACTIVE_ANON)); 1206 active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, 1207 BIT(LRU_ACTIVE_ANON)); 1208 1209 gb = (inactive + active) >> (30 - PAGE_SHIFT); 1210 if (gb) 1211 inactive_ratio = int_sqrt(10 * gb); 1212 else 1213 inactive_ratio = 1; 1214 1215 return inactive * inactive_ratio < active; 1216} 1217 1218int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg, struct zone *zone) 1219{ 1220 unsigned long active; 1221 unsigned long inactive; 1222 int zid = zone_idx(zone); 1223 int nid = zone_to_nid(zone); 1224 1225 inactive = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, 1226 BIT(LRU_INACTIVE_FILE)); 1227 active = mem_cgroup_zone_nr_lru_pages(memcg, nid, zid, 1228 BIT(LRU_ACTIVE_FILE)); 1229 1230 return (active > inactive); 1231} 1232 1233struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, 1234 struct zone *zone) 1235{ 1236 int nid = zone_to_nid(zone); 1237 int zid = zone_idx(zone); 1238 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 1239 1240 return &mz->reclaim_stat; 1241} 1242 1243struct zone_reclaim_stat * 1244mem_cgroup_get_reclaim_stat_from_page(struct page *page) 1245{ 1246 struct page_cgroup *pc; 1247 struct mem_cgroup_per_zone *mz; 1248 1249 if (mem_cgroup_disabled()) 1250 return NULL; 1251 1252 pc = lookup_page_cgroup(page); 1253 if (!PageCgroupUsed(pc)) 1254 return NULL; 1255 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 1256 smp_rmb(); 1257 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 1258 return &mz->reclaim_stat; 1259} 1260 1261unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 1262 struct list_head *dst, 1263 unsigned long *scanned, int order, 1264 isolate_mode_t mode, 1265 struct zone *z, 1266 struct mem_cgroup *mem_cont, 1267 int active, int file) 1268{ 1269 unsigned long nr_taken = 0; 1270 struct page *page; 1271 unsigned long scan; 1272 LIST_HEAD(pc_list); 1273 struct list_head *src; 1274 struct page_cgroup *pc, *tmp; 1275 int nid = zone_to_nid(z); 1276 int zid = zone_idx(z); 1277 struct mem_cgroup_per_zone *mz; 1278 int lru = LRU_FILE * file + active; 1279 int ret; 1280 1281 BUG_ON(!mem_cont); 1282 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 1283 src = &mz->lists[lru]; 1284 1285 scan = 0; 1286 list_for_each_entry_safe_reverse(pc, tmp, src, lru) { 1287 if (scan >= nr_to_scan) 1288 break; 1289 1290 if (unlikely(!PageCgroupUsed(pc))) 1291 continue; 1292 1293 page = lookup_cgroup_page(pc); 1294 1295 if (unlikely(!PageLRU(page))) 1296 continue; 1297 1298 scan++; 1299 ret = __isolate_lru_page(page, mode, file); 1300 switch (ret) { 1301 case 0: 1302 list_move(&page->lru, dst); 1303 mem_cgroup_del_lru(page); 1304 nr_taken += hpage_nr_pages(page); 1305 break; 1306 case -EBUSY: 1307 /* we don't affect global LRU but rotate in our LRU */ 1308 mem_cgroup_rotate_lru_list(page, page_lru(page)); 1309 break; 1310 default: 1311 break; 1312 } 1313 } 1314 1315 *scanned = scan; 1316 1317 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken, 1318 0, 0, 0, mode); 1319 1320 return nr_taken; 1321} 1322 1323#define mem_cgroup_from_res_counter(counter, member) \ 1324 container_of(counter, struct mem_cgroup, member) 1325 1326/** 1327 * mem_cgroup_margin - calculate chargeable space of a memory cgroup 1328 * @mem: the memory cgroup 1329 * 1330 * Returns the maximum amount of memory @mem can be charged with, in 1331 * pages. 1332 */ 1333static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) 1334{ 1335 unsigned long long margin; 1336 1337 margin = res_counter_margin(&memcg->res); 1338 if (do_swap_account) 1339 margin = min(margin, res_counter_margin(&memcg->memsw)); 1340 return margin >> PAGE_SHIFT; 1341} 1342 1343int mem_cgroup_swappiness(struct mem_cgroup *memcg) 1344{ 1345 struct cgroup *cgrp = memcg->css.cgroup; 1346 1347 /* root ? */ 1348 if (cgrp->parent == NULL) 1349 return vm_swappiness; 1350 1351 return memcg->swappiness; 1352} 1353 1354static void mem_cgroup_start_move(struct mem_cgroup *memcg) 1355{ 1356 int cpu; 1357 1358 get_online_cpus(); 1359 spin_lock(&memcg->pcp_counter_lock); 1360 for_each_online_cpu(cpu) 1361 per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; 1362 memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1; 1363 spin_unlock(&memcg->pcp_counter_lock); 1364 put_online_cpus(); 1365 1366 synchronize_rcu(); 1367} 1368 1369static void mem_cgroup_end_move(struct mem_cgroup *memcg) 1370{ 1371 int cpu; 1372 1373 if (!memcg) 1374 return; 1375 get_online_cpus(); 1376 spin_lock(&memcg->pcp_counter_lock); 1377 for_each_online_cpu(cpu) 1378 per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; 1379 memcg->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1; 1380 spin_unlock(&memcg->pcp_counter_lock); 1381 put_online_cpus(); 1382} 1383/* 1384 * 2 routines for checking "mem" is under move_account() or not. 1385 * 1386 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used 1387 * for avoiding race in accounting. If true, 1388 * pc->mem_cgroup may be overwritten. 1389 * 1390 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or 1391 * under hierarchy of moving cgroups. This is for 1392 * waiting at hith-memory prressure caused by "move". 1393 */ 1394 1395static bool mem_cgroup_stealed(struct mem_cgroup *memcg) 1396{ 1397 VM_BUG_ON(!rcu_read_lock_held()); 1398 return this_cpu_read(memcg->stat->count[MEM_CGROUP_ON_MOVE]) > 0; 1399} 1400 1401static bool mem_cgroup_under_move(struct mem_cgroup *memcg) 1402{ 1403 struct mem_cgroup *from; 1404 struct mem_cgroup *to; 1405 bool ret = false; 1406 /* 1407 * Unlike task_move routines, we access mc.to, mc.from not under 1408 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. 1409 */ 1410 spin_lock(&mc.lock); 1411 from = mc.from; 1412 to = mc.to; 1413 if (!from) 1414 goto unlock; 1415 1416 ret = mem_cgroup_same_or_subtree(memcg, from) 1417 || mem_cgroup_same_or_subtree(memcg, to); 1418unlock: 1419 spin_unlock(&mc.lock); 1420 return ret; 1421} 1422 1423static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg) 1424{ 1425 if (mc.moving_task && current != mc.moving_task) { 1426 if (mem_cgroup_under_move(memcg)) { 1427 DEFINE_WAIT(wait); 1428 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); 1429 /* moving charge context might have finished. */ 1430 if (mc.moving_task) 1431 schedule(); 1432 finish_wait(&mc.waitq, &wait); 1433 return true; 1434 } 1435 } 1436 return false; 1437} 1438 1439/** 1440 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. 1441 * @memcg: The memory cgroup that went over limit 1442 * @p: Task that is going to be killed 1443 * 1444 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is 1445 * enabled 1446 */ 1447void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 1448{ 1449 struct cgroup *task_cgrp; 1450 struct cgroup *mem_cgrp; 1451 /* 1452 * Need a buffer in BSS, can't rely on allocations. The code relies 1453 * on the assumption that OOM is serialized for memory controller. 1454 * If this assumption is broken, revisit this code. 1455 */ 1456 static char memcg_name[PATH_MAX]; 1457 int ret; 1458 1459 if (!memcg || !p) 1460 return; 1461 1462 1463 rcu_read_lock(); 1464 1465 mem_cgrp = memcg->css.cgroup; 1466 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); 1467 1468 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); 1469 if (ret < 0) { 1470 /* 1471 * Unfortunately, we are unable to convert to a useful name 1472 * But we'll still print out the usage information 1473 */ 1474 rcu_read_unlock(); 1475 goto done; 1476 } 1477 rcu_read_unlock(); 1478 1479 printk(KERN_INFO "Task in %s killed", memcg_name); 1480 1481 rcu_read_lock(); 1482 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); 1483 if (ret < 0) { 1484 rcu_read_unlock(); 1485 goto done; 1486 } 1487 rcu_read_unlock(); 1488 1489 /* 1490 * Continues from above, so we don't need an KERN_ level 1491 */ 1492 printk(KERN_CONT " as a result of limit of %s\n", memcg_name); 1493done: 1494 1495 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", 1496 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, 1497 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, 1498 res_counter_read_u64(&memcg->res, RES_FAILCNT)); 1499 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " 1500 "failcnt %llu\n", 1501 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, 1502 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, 1503 res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); 1504} 1505 1506/* 1507 * This function returns the number of memcg under hierarchy tree. Returns 1508 * 1(self count) if no children. 1509 */ 1510static int mem_cgroup_count_children(struct mem_cgroup *memcg) 1511{ 1512 int num = 0; 1513 struct mem_cgroup *iter; 1514 1515 for_each_mem_cgroup_tree(iter, memcg) 1516 num++; 1517 return num; 1518} 1519 1520/* 1521 * Return the memory (and swap, if configured) limit for a memcg. 1522 */ 1523u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) 1524{ 1525 u64 limit; 1526 u64 memsw; 1527 1528 limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 1529 limit += total_swap_pages << PAGE_SHIFT; 1530 1531 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 1532 /* 1533 * If memsw is finite and limits the amount of swap space available 1534 * to this memcg, return that limit. 1535 */ 1536 return min(limit, memsw); 1537} 1538 1539/* 1540 * Visit the first child (need not be the first child as per the ordering 1541 * of the cgroup list, since we track last_scanned_child) of @mem and use 1542 * that to reclaim free pages from. 1543 */ 1544static struct mem_cgroup * 1545mem_cgroup_select_victim(struct mem_cgroup *root_memcg) 1546{ 1547 struct mem_cgroup *ret = NULL; 1548 struct cgroup_subsys_state *css; 1549 int nextid, found; 1550 1551 if (!root_memcg->use_hierarchy) { 1552 css_get(&root_memcg->css); 1553 ret = root_memcg; 1554 } 1555 1556 while (!ret) { 1557 rcu_read_lock(); 1558 nextid = root_memcg->last_scanned_child + 1; 1559 css = css_get_next(&mem_cgroup_subsys, nextid, &root_memcg->css, 1560 &found); 1561 if (css && css_tryget(css)) 1562 ret = container_of(css, struct mem_cgroup, css); 1563 1564 rcu_read_unlock(); 1565 /* Updates scanning parameter */ 1566 if (!css) { 1567 /* this means start scan from ID:1 */ 1568 root_memcg->last_scanned_child = 0; 1569 } else 1570 root_memcg->last_scanned_child = found; 1571 } 1572 1573 return ret; 1574} 1575 1576/** 1577 * test_mem_cgroup_node_reclaimable 1578 * @mem: the target memcg 1579 * @nid: the node ID to be checked. 1580 * @noswap : specify true here if the user wants flle only information. 1581 * 1582 * This function returns whether the specified memcg contains any 1583 * reclaimable pages on a node. Returns true if there are any reclaimable 1584 * pages in the node. 1585 */ 1586static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg, 1587 int nid, bool noswap) 1588{ 1589 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE)) 1590 return true; 1591 if (noswap || !total_swap_pages) 1592 return false; 1593 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON)) 1594 return true; 1595 return false; 1596 1597} 1598#if MAX_NUMNODES > 1 1599 1600/* 1601 * Always updating the nodemask is not very good - even if we have an empty 1602 * list or the wrong list here, we can start from some node and traverse all 1603 * nodes based on the zonelist. So update the list loosely once per 10 secs. 1604 * 1605 */ 1606static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg) 1607{ 1608 int nid; 1609 /* 1610 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET 1611 * pagein/pageout changes since the last update. 1612 */ 1613 if (!atomic_read(&memcg->numainfo_events)) 1614 return; 1615 if (atomic_inc_return(&memcg->numainfo_updating) > 1) 1616 return; 1617 1618 /* make a nodemask where this memcg uses memory from */ 1619 memcg->scan_nodes = node_states[N_HIGH_MEMORY]; 1620 1621 for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) { 1622 1623 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false)) 1624 node_clear(nid, memcg->scan_nodes); 1625 } 1626 1627 atomic_set(&memcg->numainfo_events, 0); 1628 atomic_set(&memcg->numainfo_updating, 0); 1629} 1630 1631/* 1632 * Selecting a node where we start reclaim from. Because what we need is just 1633 * reducing usage counter, start from anywhere is O,K. Considering 1634 * memory reclaim from current node, there are pros. and cons. 1635 * 1636 * Freeing memory from current node means freeing memory from a node which 1637 * we'll use or we've used. So, it may make LRU bad. And if several threads 1638 * hit limits, it will see a contention on a node. But freeing from remote 1639 * node means more costs for memory reclaim because of memory latency. 1640 * 1641 * Now, we use round-robin. Better algorithm is welcomed. 1642 */ 1643int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) 1644{ 1645 int node; 1646 1647 mem_cgroup_may_update_nodemask(memcg); 1648 node = memcg->last_scanned_node; 1649 1650 node = next_node(node, memcg->scan_nodes); 1651 if (node == MAX_NUMNODES) 1652 node = first_node(memcg->scan_nodes); 1653 /* 1654 * We call this when we hit limit, not when pages are added to LRU. 1655 * No LRU may hold pages because all pages are UNEVICTABLE or 1656 * memcg is too small and all pages are not on LRU. In that case, 1657 * we use curret node. 1658 */ 1659 if (unlikely(node == MAX_NUMNODES)) 1660 node = numa_node_id(); 1661 1662 memcg->last_scanned_node = node; 1663 return node; 1664} 1665 1666/* 1667 * Check all nodes whether it contains reclaimable pages or not. 1668 * For quick scan, we make use of scan_nodes. This will allow us to skip 1669 * unused nodes. But scan_nodes is lazily updated and may not cotain 1670 * enough new information. We need to do double check. 1671 */ 1672bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) 1673{ 1674 int nid; 1675 1676 /* 1677 * quick check...making use of scan_node. 1678 * We can skip unused nodes. 1679 */ 1680 if (!nodes_empty(memcg->scan_nodes)) { 1681 for (nid = first_node(memcg->scan_nodes); 1682 nid < MAX_NUMNODES; 1683 nid = next_node(nid, memcg->scan_nodes)) { 1684 1685 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) 1686 return true; 1687 } 1688 } 1689 /* 1690 * Check rest of nodes. 1691 */ 1692 for_each_node_state(nid, N_HIGH_MEMORY) { 1693 if (node_isset(nid, memcg->scan_nodes)) 1694 continue; 1695 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap)) 1696 return true; 1697 } 1698 return false; 1699} 1700 1701#else 1702int mem_cgroup_select_victim_node(struct mem_cgroup *memcg) 1703{ 1704 return 0; 1705} 1706 1707bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap) 1708{ 1709 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap); 1710} 1711#endif 1712 1713/* 1714 * Scan the hierarchy if needed to reclaim memory. We remember the last child 1715 * we reclaimed from, so that we don't end up penalizing one child extensively 1716 * based on its position in the children list. 1717 * 1718 * root_memcg is the original ancestor that we've been reclaim from. 1719 * 1720 * We give up and return to the caller when we visit root_memcg twice. 1721 * (other groups can be removed while we're walking....) 1722 * 1723 * If shrink==true, for avoiding to free too much, this returns immedieately. 1724 */ 1725static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_memcg, 1726 struct zone *zone, 1727 gfp_t gfp_mask, 1728 unsigned long reclaim_options, 1729 unsigned long *total_scanned) 1730{ 1731 struct mem_cgroup *victim; 1732 int ret, total = 0; 1733 int loop = 0; 1734 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP; 1735 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK; 1736 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT; 1737 unsigned long excess; 1738 unsigned long nr_scanned; 1739 1740 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT; 1741 1742 /* If memsw_is_minimum==1, swap-out is of-no-use. */ 1743 if (!check_soft && !shrink && root_memcg->memsw_is_minimum) 1744 noswap = true; 1745 1746 while (1) { 1747 victim = mem_cgroup_select_victim(root_memcg); 1748 if (victim == root_memcg) { 1749 loop++; 1750 /* 1751 * We are not draining per cpu cached charges during 1752 * soft limit reclaim because global reclaim doesn't 1753 * care about charges. It tries to free some memory and 1754 * charges will not give any. 1755 */ 1756 if (!check_soft && loop >= 1) 1757 drain_all_stock_async(root_memcg); 1758 if (loop >= 2) { 1759 /* 1760 * If we have not been able to reclaim 1761 * anything, it might because there are 1762 * no reclaimable pages under this hierarchy 1763 */ 1764 if (!check_soft || !total) { 1765 css_put(&victim->css); 1766 break; 1767 } 1768 /* 1769 * We want to do more targeted reclaim. 1770 * excess >> 2 is not to excessive so as to 1771 * reclaim too much, nor too less that we keep 1772 * coming back to reclaim from this cgroup 1773 */ 1774 if (total >= (excess >> 2) || 1775 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) { 1776 css_put(&victim->css); 1777 break; 1778 } 1779 } 1780 } 1781 if (!mem_cgroup_reclaimable(victim, noswap)) { 1782 /* this cgroup's local usage == 0 */ 1783 css_put(&victim->css); 1784 continue; 1785 } 1786 /* we use swappiness of local cgroup */ 1787 if (check_soft) { 1788 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, 1789 noswap, zone, &nr_scanned); 1790 *total_scanned += nr_scanned; 1791 } else 1792 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, 1793 noswap); 1794 css_put(&victim->css); 1795 /* 1796 * At shrinking usage, we can't check we should stop here or 1797 * reclaim more. It's depends on callers. last_scanned_child 1798 * will work enough for keeping fairness under tree. 1799 */ 1800 if (shrink) 1801 return ret; 1802 total += ret; 1803 if (check_soft) { 1804 if (!res_counter_soft_limit_excess(&root_memcg->res)) 1805 return total; 1806 } else if (mem_cgroup_margin(root_memcg)) 1807 return total; 1808 } 1809 return total; 1810} 1811 1812/* 1813 * Check OOM-Killer is already running under our hierarchy. 1814 * If someone is running, return false. 1815 * Has to be called with memcg_oom_lock 1816 */ 1817static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg) 1818{ 1819 struct mem_cgroup *iter, *failed = NULL; 1820 bool cond = true; 1821 1822 for_each_mem_cgroup_tree_cond(iter, memcg, cond) { 1823 if (iter->oom_lock) { 1824 /* 1825 * this subtree of our hierarchy is already locked 1826 * so we cannot give a lock. 1827 */ 1828 failed = iter; 1829 cond = false; 1830 } else 1831 iter->oom_lock = true; 1832 } 1833 1834 if (!failed) 1835 return true; 1836 1837 /* 1838 * OK, we failed to lock the whole subtree so we have to clean up 1839 * what we set up to the failing subtree 1840 */ 1841 cond = true; 1842 for_each_mem_cgroup_tree_cond(iter, memcg, cond) { 1843 if (iter == failed) { 1844 cond = false; 1845 continue; 1846 } 1847 iter->oom_lock = false; 1848 } 1849 return false; 1850} 1851 1852/* 1853 * Has to be called with memcg_oom_lock 1854 */ 1855static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg) 1856{ 1857 struct mem_cgroup *iter; 1858 1859 for_each_mem_cgroup_tree(iter, memcg) 1860 iter->oom_lock = false; 1861 return 0; 1862} 1863 1864static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg) 1865{ 1866 struct mem_cgroup *iter; 1867 1868 for_each_mem_cgroup_tree(iter, memcg) 1869 atomic_inc(&iter->under_oom); 1870} 1871 1872static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg) 1873{ 1874 struct mem_cgroup *iter; 1875 1876 /* 1877 * When a new child is created while the hierarchy is under oom, 1878 * mem_cgroup_oom_lock() may not be called. We have to use 1879 * atomic_add_unless() here. 1880 */ 1881 for_each_mem_cgroup_tree(iter, memcg) 1882 atomic_add_unless(&iter->under_oom, -1, 0); 1883} 1884 1885static DEFINE_SPINLOCK(memcg_oom_lock); 1886static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); 1887 1888struct oom_wait_info { 1889 struct mem_cgroup *mem; 1890 wait_queue_t wait; 1891}; 1892 1893static int memcg_oom_wake_function(wait_queue_t *wait, 1894 unsigned mode, int sync, void *arg) 1895{ 1896 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg, 1897 *oom_wait_memcg; 1898 struct oom_wait_info *oom_wait_info; 1899 1900 oom_wait_info = container_of(wait, struct oom_wait_info, wait); 1901 oom_wait_memcg = oom_wait_info->mem; 1902 1903 /* 1904 * Both of oom_wait_info->mem and wake_mem are stable under us. 1905 * Then we can use css_is_ancestor without taking care of RCU. 1906 */ 1907 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg) 1908 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg)) 1909 return 0; 1910 return autoremove_wake_function(wait, mode, sync, arg); 1911} 1912 1913static void memcg_wakeup_oom(struct mem_cgroup *memcg) 1914{ 1915 /* for filtering, pass "memcg" as argument. */ 1916 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg); 1917} 1918 1919static void memcg_oom_recover(struct mem_cgroup *memcg) 1920{ 1921 if (memcg && atomic_read(&memcg->under_oom)) 1922 memcg_wakeup_oom(memcg); 1923} 1924 1925/* 1926 * try to call OOM killer. returns false if we should exit memory-reclaim loop. 1927 */ 1928bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask) 1929{ 1930 struct oom_wait_info owait; 1931 bool locked, need_to_kill; 1932 1933 owait.mem = memcg; 1934 owait.wait.flags = 0; 1935 owait.wait.func = memcg_oom_wake_function; 1936 owait.wait.private = current; 1937 INIT_LIST_HEAD(&owait.wait.task_list); 1938 need_to_kill = true; 1939 mem_cgroup_mark_under_oom(memcg); 1940 1941 /* At first, try to OOM lock hierarchy under memcg.*/ 1942 spin_lock(&memcg_oom_lock); 1943 locked = mem_cgroup_oom_lock(memcg); 1944 /* 1945 * Even if signal_pending(), we can't quit charge() loop without 1946 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL 1947 * under OOM is always welcomed, use TASK_KILLABLE here. 1948 */ 1949 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); 1950 if (!locked || memcg->oom_kill_disable) 1951 need_to_kill = false; 1952 if (locked) 1953 mem_cgroup_oom_notify(memcg); 1954 spin_unlock(&memcg_oom_lock); 1955 1956 if (need_to_kill) { 1957 finish_wait(&memcg_oom_waitq, &owait.wait); 1958 mem_cgroup_out_of_memory(memcg, mask); 1959 } else { 1960 schedule(); 1961 finish_wait(&memcg_oom_waitq, &owait.wait); 1962 } 1963 spin_lock(&memcg_oom_lock); 1964 if (locked) 1965 mem_cgroup_oom_unlock(memcg); 1966 memcg_wakeup_oom(memcg); 1967 spin_unlock(&memcg_oom_lock); 1968 1969 mem_cgroup_unmark_under_oom(memcg); 1970 1971 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) 1972 return false; 1973 /* Give chance to dying process */ 1974 schedule_timeout_uninterruptible(1); 1975 return true; 1976} 1977 1978/* 1979 * Currently used to update mapped file statistics, but the routine can be 1980 * generalized to update other statistics as well. 1981 * 1982 * Notes: Race condition 1983 * 1984 * We usually use page_cgroup_lock() for accessing page_cgroup member but 1985 * it tends to be costly. But considering some conditions, we doesn't need 1986 * to do so _always_. 1987 * 1988 * Considering "charge", lock_page_cgroup() is not required because all 1989 * file-stat operations happen after a page is attached to radix-tree. There 1990 * are no race with "charge". 1991 * 1992 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup 1993 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even 1994 * if there are race with "uncharge". Statistics itself is properly handled 1995 * by flags. 1996 * 1997 * Considering "move", this is an only case we see a race. To make the race 1998 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are 1999 * possibility of race condition. If there is, we take a lock. 2000 */ 2001 2002void mem_cgroup_update_page_stat(struct page *page, 2003 enum mem_cgroup_page_stat_item idx, int val) 2004{ 2005 struct mem_cgroup *memcg; 2006 struct page_cgroup *pc = lookup_page_cgroup(page); 2007 bool need_unlock = false; 2008 unsigned long uninitialized_var(flags); 2009 2010 if (unlikely(!pc)) 2011 return; 2012 2013 rcu_read_lock(); 2014 memcg = pc->mem_cgroup; 2015 if (unlikely(!memcg || !PageCgroupUsed(pc))) 2016 goto out; 2017 /* pc->mem_cgroup is unstable ? */ 2018 if (unlikely(mem_cgroup_stealed(memcg)) || PageTransHuge(page)) { 2019 /* take a lock against to access pc->mem_cgroup */ 2020 move_lock_page_cgroup(pc, &flags); 2021 need_unlock = true; 2022 memcg = pc->mem_cgroup; 2023 if (!memcg || !PageCgroupUsed(pc)) 2024 goto out; 2025 } 2026 2027 switch (idx) { 2028 case MEMCG_NR_FILE_MAPPED: 2029 if (val > 0) 2030 SetPageCgroupFileMapped(pc); 2031 else if (!page_mapped(page)) 2032 ClearPageCgroupFileMapped(pc); 2033 idx = MEM_CGROUP_STAT_FILE_MAPPED; 2034 break; 2035 default: 2036 BUG(); 2037 } 2038 2039 this_cpu_add(memcg->stat->count[idx], val); 2040 2041out: 2042 if (unlikely(need_unlock)) 2043 move_unlock_page_cgroup(pc, &flags); 2044 rcu_read_unlock(); 2045 return; 2046} 2047EXPORT_SYMBOL(mem_cgroup_update_page_stat); 2048 2049/* 2050 * size of first charge trial. "32" comes from vmscan.c's magic value. 2051 * TODO: maybe necessary to use big numbers in big irons. 2052 */ 2053#define CHARGE_BATCH 32U 2054struct memcg_stock_pcp { 2055 struct mem_cgroup *cached; /* this never be root cgroup */ 2056 unsigned int nr_pages; 2057 struct work_struct work; 2058 unsigned long flags; 2059#define FLUSHING_CACHED_CHARGE (0) 2060}; 2061static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); 2062static DEFINE_MUTEX(percpu_charge_mutex); 2063 2064/* 2065 * Try to consume stocked charge on this cpu. If success, one page is consumed 2066 * from local stock and true is returned. If the stock is 0 or charges from a 2067 * cgroup which is not current target, returns false. This stock will be 2068 * refilled. 2069 */ 2070static bool consume_stock(struct mem_cgroup *memcg) 2071{ 2072 struct memcg_stock_pcp *stock; 2073 bool ret = true; 2074 2075 stock = &get_cpu_var(memcg_stock); 2076 if (memcg == stock->cached && stock->nr_pages) 2077 stock->nr_pages--; 2078 else /* need to call res_counter_charge */ 2079 ret = false; 2080 put_cpu_var(memcg_stock); 2081 return ret; 2082} 2083 2084/* 2085 * Returns stocks cached in percpu to res_counter and reset cached information. 2086 */ 2087static void drain_stock(struct memcg_stock_pcp *stock) 2088{ 2089 struct mem_cgroup *old = stock->cached; 2090 2091 if (stock->nr_pages) { 2092 unsigned long bytes = stock->nr_pages * PAGE_SIZE; 2093 2094 res_counter_uncharge(&old->res, bytes); 2095 if (do_swap_account) 2096 res_counter_uncharge(&old->memsw, bytes); 2097 stock->nr_pages = 0; 2098 } 2099 stock->cached = NULL; 2100} 2101 2102/* 2103 * This must be called under preempt disabled or must be called by 2104 * a thread which is pinned to local cpu. 2105 */ 2106static void drain_local_stock(struct work_struct *dummy) 2107{ 2108 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); 2109 drain_stock(stock); 2110 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags); 2111} 2112 2113/* 2114 * Cache charges(val) which is from res_counter, to local per_cpu area. 2115 * This will be consumed by consume_stock() function, later. 2116 */ 2117static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages) 2118{ 2119 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); 2120 2121 if (stock->cached != memcg) { /* reset if necessary */ 2122 drain_stock(stock); 2123 stock->cached = memcg; 2124 } 2125 stock->nr_pages += nr_pages; 2126 put_cpu_var(memcg_stock); 2127} 2128 2129/* 2130 * Drains all per-CPU charge caches for given root_memcg resp. subtree 2131 * of the hierarchy under it. sync flag says whether we should block 2132 * until the work is done. 2133 */ 2134static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync) 2135{ 2136 int cpu, curcpu; 2137 2138 /* Notify other cpus that system-wide "drain" is running */ 2139 get_online_cpus(); 2140 curcpu = get_cpu(); 2141 for_each_online_cpu(cpu) { 2142 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); 2143 struct mem_cgroup *memcg; 2144 2145 memcg = stock->cached; 2146 if (!memcg || !stock->nr_pages) 2147 continue; 2148 if (!mem_cgroup_same_or_subtree(root_memcg, memcg)) 2149 continue; 2150 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) { 2151 if (cpu == curcpu) 2152 drain_local_stock(&stock->work); 2153 else 2154 schedule_work_on(cpu, &stock->work); 2155 } 2156 } 2157 put_cpu(); 2158 2159 if (!sync) 2160 goto out; 2161 2162 for_each_online_cpu(cpu) { 2163 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); 2164 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) 2165 flush_work(&stock->work); 2166 } 2167out: 2168 put_online_cpus(); 2169} 2170 2171/* 2172 * Tries to drain stocked charges in other cpus. This function is asynchronous 2173 * and just put a work per cpu for draining localy on each cpu. Caller can 2174 * expects some charges will be back to res_counter later but cannot wait for 2175 * it. 2176 */ 2177static void drain_all_stock_async(struct mem_cgroup *root_memcg) 2178{ 2179 /* 2180 * If someone calls draining, avoid adding more kworker runs. 2181 */ 2182 if (!mutex_trylock(&percpu_charge_mutex)) 2183 return; 2184 drain_all_stock(root_memcg, false); 2185 mutex_unlock(&percpu_charge_mutex); 2186} 2187 2188/* This is a synchronous drain interface. */ 2189static void drain_all_stock_sync(struct mem_cgroup *root_memcg) 2190{ 2191 /* called when force_empty is called */ 2192 mutex_lock(&percpu_charge_mutex); 2193 drain_all_stock(root_memcg, true); 2194 mutex_unlock(&percpu_charge_mutex); 2195} 2196 2197/* 2198 * This function drains percpu counter value from DEAD cpu and 2199 * move it to local cpu. Note that this function can be preempted. 2200 */ 2201static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu) 2202{ 2203 int i; 2204 2205 spin_lock(&memcg->pcp_counter_lock); 2206 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) { 2207 long x = per_cpu(memcg->stat->count[i], cpu); 2208 2209 per_cpu(memcg->stat->count[i], cpu) = 0; 2210 memcg->nocpu_base.count[i] += x; 2211 } 2212 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { 2213 unsigned long x = per_cpu(memcg->stat->events[i], cpu); 2214 2215 per_cpu(memcg->stat->events[i], cpu) = 0; 2216 memcg->nocpu_base.events[i] += x; 2217 } 2218 /* need to clear ON_MOVE value, works as a kind of lock. */ 2219 per_cpu(memcg->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0; 2220 spin_unlock(&memcg->pcp_counter_lock); 2221} 2222 2223static void synchronize_mem_cgroup_on_move(struct mem_cgroup *memcg, int cpu) 2224{ 2225 int idx = MEM_CGROUP_ON_MOVE; 2226 2227 spin_lock(&memcg->pcp_counter_lock); 2228 per_cpu(memcg->stat->count[idx], cpu) = memcg->nocpu_base.count[idx]; 2229 spin_unlock(&memcg->pcp_counter_lock); 2230} 2231 2232static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, 2233 unsigned long action, 2234 void *hcpu) 2235{ 2236 int cpu = (unsigned long)hcpu; 2237 struct memcg_stock_pcp *stock; 2238 struct mem_cgroup *iter; 2239 2240 if ((action == CPU_ONLINE)) { 2241 for_each_mem_cgroup_all(iter) 2242 synchronize_mem_cgroup_on_move(iter, cpu); 2243 return NOTIFY_OK; 2244 } 2245 2246 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN) 2247 return NOTIFY_OK; 2248 2249 for_each_mem_cgroup_all(iter) 2250 mem_cgroup_drain_pcp_counter(iter, cpu); 2251 2252 stock = &per_cpu(memcg_stock, cpu); 2253 drain_stock(stock); 2254 return NOTIFY_OK; 2255} 2256 2257 2258/* See __mem_cgroup_try_charge() for details */ 2259enum { 2260 CHARGE_OK, /* success */ 2261 CHARGE_RETRY, /* need to retry but retry is not bad */ 2262 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ 2263 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ 2264 CHARGE_OOM_DIE, /* the current is killed because of OOM */ 2265}; 2266 2267static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 2268 unsigned int nr_pages, bool oom_check) 2269{ 2270 unsigned long csize = nr_pages * PAGE_SIZE; 2271 struct mem_cgroup *mem_over_limit; 2272 struct res_counter *fail_res; 2273 unsigned long flags = 0; 2274 int ret; 2275 2276 ret = res_counter_charge(&memcg->res, csize, &fail_res); 2277 2278 if (likely(!ret)) { 2279 if (!do_swap_account) 2280 return CHARGE_OK; 2281 ret = res_counter_charge(&memcg->memsw, csize, &fail_res); 2282 if (likely(!ret)) 2283 return CHARGE_OK; 2284 2285 res_counter_uncharge(&memcg->res, csize); 2286 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); 2287 flags |= MEM_CGROUP_RECLAIM_NOSWAP; 2288 } else 2289 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); 2290 /* 2291 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch 2292 * of regular pages (CHARGE_BATCH), or a single regular page (1). 2293 * 2294 * Never reclaim on behalf of optional batching, retry with a 2295 * single page instead. 2296 */ 2297 if (nr_pages == CHARGE_BATCH) 2298 return CHARGE_RETRY; 2299 2300 if (!(gfp_mask & __GFP_WAIT)) 2301 return CHARGE_WOULDBLOCK; 2302 2303 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, 2304 gfp_mask, flags, NULL); 2305 if (mem_cgroup_margin(mem_over_limit) >= nr_pages) 2306 return CHARGE_RETRY; 2307 /* 2308 * Even though the limit is exceeded at this point, reclaim 2309 * may have been able to free some pages. Retry the charge 2310 * before killing the task. 2311 * 2312 * Only for regular pages, though: huge pages are rather 2313 * unlikely to succeed so close to the limit, and we fall back 2314 * to regular pages anyway in case of failure. 2315 */ 2316 if (nr_pages == 1 && ret) 2317 return CHARGE_RETRY; 2318 2319 /* 2320 * At task move, charge accounts can be doubly counted. So, it's 2321 * better to wait until the end of task_move if something is going on. 2322 */ 2323 if (mem_cgroup_wait_acct_move(mem_over_limit)) 2324 return CHARGE_RETRY; 2325 2326 /* If we don't need to call oom-killer at el, return immediately */ 2327 if (!oom_check) 2328 return CHARGE_NOMEM; 2329 /* check OOM */ 2330 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) 2331 return CHARGE_OOM_DIE; 2332 2333 return CHARGE_RETRY; 2334} 2335 2336/* 2337 * Unlike exported interface, "oom" parameter is added. if oom==true, 2338 * oom-killer can be invoked. 2339 */ 2340static int __mem_cgroup_try_charge(struct mm_struct *mm, 2341 gfp_t gfp_mask, 2342 unsigned int nr_pages, 2343 struct mem_cgroup **ptr, 2344 bool oom) 2345{ 2346 unsigned int batch = max(CHARGE_BATCH, nr_pages); 2347 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 2348 struct mem_cgroup *memcg = NULL; 2349 int ret; 2350 2351 /* 2352 * Unlike gloval-vm's OOM-kill, we're not in memory shortage 2353 * in system level. So, allow to go ahead dying process in addition to 2354 * MEMDIE process. 2355 */ 2356 if (unlikely(test_thread_flag(TIF_MEMDIE) 2357 || fatal_signal_pending(current))) 2358 goto bypass; 2359 2360 /* 2361 * We always charge the cgroup the mm_struct belongs to. 2362 * The mm_struct's mem_cgroup changes on task migration if the 2363 * thread group leader migrates. It's possible that mm is not 2364 * set, if so charge the init_mm (happens for pagecache usage). 2365 */ 2366 if (!*ptr && !mm) 2367 goto bypass; 2368again: 2369 if (*ptr) { /* css should be a valid one */ 2370 memcg = *ptr; 2371 VM_BUG_ON(css_is_removed(&memcg->css)); 2372 if (mem_cgroup_is_root(memcg)) 2373 goto done; 2374 if (nr_pages == 1 && consume_stock(memcg)) 2375 goto done; 2376 css_get(&memcg->css); 2377 } else { 2378 struct task_struct *p; 2379 2380 rcu_read_lock(); 2381 p = rcu_dereference(mm->owner); 2382 /* 2383 * Because we don't have task_lock(), "p" can exit. 2384 * In that case, "memcg" can point to root or p can be NULL with 2385 * race with swapoff. Then, we have small risk of mis-accouning. 2386 * But such kind of mis-account by race always happens because 2387 * we don't have cgroup_mutex(). It's overkill and we allo that 2388 * small race, here. 2389 * (*) swapoff at el will charge against mm-struct not against 2390 * task-struct. So, mm->owner can be NULL. 2391 */ 2392 memcg = mem_cgroup_from_task(p); 2393 if (!memcg || mem_cgroup_is_root(memcg)) { 2394 rcu_read_unlock(); 2395 goto done; 2396 } 2397 if (nr_pages == 1 && consume_stock(memcg)) { 2398 /* 2399 * It seems dagerous to access memcg without css_get(). 2400 * But considering how consume_stok works, it's not 2401 * necessary. If consume_stock success, some charges 2402 * from this memcg are cached on this cpu. So, we 2403 * don't need to call css_get()/css_tryget() before 2404 * calling consume_stock(). 2405 */ 2406 rcu_read_unlock(); 2407 goto done; 2408 } 2409 /* after here, we may be blocked. we need to get refcnt */ 2410 if (!css_tryget(&memcg->css)) { 2411 rcu_read_unlock(); 2412 goto again; 2413 } 2414 rcu_read_unlock(); 2415 } 2416 2417 do { 2418 bool oom_check; 2419 2420 /* If killed, bypass charge */ 2421 if (fatal_signal_pending(current)) { 2422 css_put(&memcg->css); 2423 goto bypass; 2424 } 2425 2426 oom_check = false; 2427 if (oom && !nr_oom_retries) { 2428 oom_check = true; 2429 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 2430 } 2431 2432 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check); 2433 switch (ret) { 2434 case CHARGE_OK: 2435 break; 2436 case CHARGE_RETRY: /* not in OOM situation but retry */ 2437 batch = nr_pages; 2438 css_put(&memcg->css); 2439 memcg = NULL; 2440 goto again; 2441 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ 2442 css_put(&memcg->css); 2443 goto nomem; 2444 case CHARGE_NOMEM: /* OOM routine works */ 2445 if (!oom) { 2446 css_put(&memcg->css); 2447 goto nomem; 2448 } 2449 /* If oom, we never return -ENOMEM */ 2450 nr_oom_retries--; 2451 break; 2452 case CHARGE_OOM_DIE: /* Killed by OOM Killer */ 2453 css_put(&memcg->css); 2454 goto bypass; 2455 } 2456 } while (ret != CHARGE_OK); 2457 2458 if (batch > nr_pages) 2459 refill_stock(memcg, batch - nr_pages); 2460 css_put(&memcg->css); 2461done: 2462 *ptr = memcg; 2463 return 0; 2464nomem: 2465 *ptr = NULL; 2466 return -ENOMEM; 2467bypass: 2468 *ptr = NULL; 2469 return 0; 2470} 2471 2472/* 2473 * Somemtimes we have to undo a charge we got by try_charge(). 2474 * This function is for that and do uncharge, put css's refcnt. 2475 * gotten by try_charge(). 2476 */ 2477static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg, 2478 unsigned int nr_pages) 2479{ 2480 if (!mem_cgroup_is_root(memcg)) { 2481 unsigned long bytes = nr_pages * PAGE_SIZE; 2482 2483 res_counter_uncharge(&memcg->res, bytes); 2484 if (do_swap_account) 2485 res_counter_uncharge(&memcg->memsw, bytes); 2486 } 2487} 2488 2489/* 2490 * A helper function to get mem_cgroup from ID. must be called under 2491 * rcu_read_lock(). The caller must check css_is_removed() or some if 2492 * it's concern. (dropping refcnt from swap can be called against removed 2493 * memcg.) 2494 */ 2495static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) 2496{ 2497 struct cgroup_subsys_state *css; 2498 2499 /* ID 0 is unused ID */ 2500 if (!id) 2501 return NULL; 2502 css = css_lookup(&mem_cgroup_subsys, id); 2503 if (!css) 2504 return NULL; 2505 return container_of(css, struct mem_cgroup, css); 2506} 2507 2508struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) 2509{ 2510 struct mem_cgroup *memcg = NULL; 2511 struct page_cgroup *pc; 2512 unsigned short id; 2513 swp_entry_t ent; 2514 2515 VM_BUG_ON(!PageLocked(page)); 2516 2517 pc = lookup_page_cgroup(page); 2518 lock_page_cgroup(pc); 2519 if (PageCgroupUsed(pc)) { 2520 memcg = pc->mem_cgroup; 2521 if (memcg && !css_tryget(&memcg->css)) 2522 memcg = NULL; 2523 } else if (PageSwapCache(page)) { 2524 ent.val = page_private(page); 2525 id = lookup_swap_cgroup(ent); 2526 rcu_read_lock(); 2527 memcg = mem_cgroup_lookup(id); 2528 if (memcg && !css_tryget(&memcg->css)) 2529 memcg = NULL; 2530 rcu_read_unlock(); 2531 } 2532 unlock_page_cgroup(pc); 2533 return memcg; 2534} 2535 2536static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg, 2537 struct page *page, 2538 unsigned int nr_pages, 2539 struct page_cgroup *pc, 2540 enum charge_type ctype) 2541{ 2542 lock_page_cgroup(pc); 2543 if (unlikely(PageCgroupUsed(pc))) { 2544 unlock_page_cgroup(pc); 2545 __mem_cgroup_cancel_charge(memcg, nr_pages); 2546 return; 2547 } 2548 /* 2549 * we don't need page_cgroup_lock about tail pages, becase they are not 2550 * accessed by any other context at this point. 2551 */ 2552 pc->mem_cgroup = memcg; 2553 /* 2554 * We access a page_cgroup asynchronously without lock_page_cgroup(). 2555 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup 2556 * is accessed after testing USED bit. To make pc->mem_cgroup visible 2557 * before USED bit, we need memory barrier here. 2558 * See mem_cgroup_add_lru_list(), etc. 2559 */ 2560 smp_wmb(); 2561 switch (ctype) { 2562 case MEM_CGROUP_CHARGE_TYPE_CACHE: 2563 case MEM_CGROUP_CHARGE_TYPE_SHMEM: 2564 SetPageCgroupCache(pc); 2565 SetPageCgroupUsed(pc); 2566 break; 2567 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 2568 ClearPageCgroupCache(pc); 2569 SetPageCgroupUsed(pc); 2570 break; 2571 default: 2572 break; 2573 } 2574 2575 mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), nr_pages); 2576 unlock_page_cgroup(pc); 2577 /* 2578 * "charge_statistics" updated event counter. Then, check it. 2579 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. 2580 * if they exceeds softlimit. 2581 */ 2582 memcg_check_events(memcg, page); 2583} 2584 2585#ifdef CONFIG_TRANSPARENT_HUGEPAGE 2586 2587#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ 2588 (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION)) 2589/* 2590 * Because tail pages are not marked as "used", set it. We're under 2591 * zone->lru_lock, 'splitting on pmd' and compund_lock. 2592 */ 2593void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail) 2594{ 2595 struct page_cgroup *head_pc = lookup_page_cgroup(head); 2596 struct page_cgroup *tail_pc = lookup_page_cgroup(tail); 2597 unsigned long flags; 2598 2599 if (mem_cgroup_disabled()) 2600 return; 2601 /* 2602 * We have no races with charge/uncharge but will have races with 2603 * page state accounting. 2604 */ 2605 move_lock_page_cgroup(head_pc, &flags); 2606 2607 tail_pc->mem_cgroup = head_pc->mem_cgroup; 2608 smp_wmb(); /* see __commit_charge() */ 2609 if (PageCgroupAcctLRU(head_pc)) { 2610 enum lru_list lru; 2611 struct mem_cgroup_per_zone *mz; 2612 2613 /* 2614 * LRU flags cannot be copied because we need to add tail 2615 *.page to LRU by generic call and our hook will be called. 2616 * We hold lru_lock, then, reduce counter directly. 2617 */ 2618 lru = page_lru(head); 2619 mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head); 2620 MEM_CGROUP_ZSTAT(mz, lru) -= 1; 2621 } 2622 tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; 2623 move_unlock_page_cgroup(head_pc, &flags); 2624} 2625#endif 2626 2627/** 2628 * mem_cgroup_move_account - move account of the page 2629 * @page: the page 2630 * @nr_pages: number of regular pages (>1 for huge pages) 2631 * @pc: page_cgroup of the page. 2632 * @from: mem_cgroup which the page is moved from. 2633 * @to: mem_cgroup which the page is moved to. @from != @to. 2634 * @uncharge: whether we should call uncharge and css_put against @from. 2635 * 2636 * The caller must confirm following. 2637 * - page is not on LRU (isolate_page() is useful.) 2638 * - compound_lock is held when nr_pages > 1 2639 * 2640 * This function doesn't do "charge" nor css_get to new cgroup. It should be 2641 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is 2642 * true, this function does "uncharge" from old cgroup, but it doesn't if 2643 * @uncharge is false, so a caller should do "uncharge". 2644 */ 2645static int mem_cgroup_move_account(struct page *page, 2646 unsigned int nr_pages, 2647 struct page_cgroup *pc, 2648 struct mem_cgroup *from, 2649 struct mem_cgroup *to, 2650 bool uncharge) 2651{ 2652 unsigned long flags; 2653 int ret; 2654 2655 VM_BUG_ON(from == to); 2656 VM_BUG_ON(PageLRU(page)); 2657 /* 2658 * The page is isolated from LRU. So, collapse function 2659 * will not handle this page. But page splitting can happen. 2660 * Do this check under compound_page_lock(). The caller should 2661 * hold it. 2662 */ 2663 ret = -EBUSY; 2664 if (nr_pages > 1 && !PageTransHuge(page)) 2665 goto out; 2666 2667 lock_page_cgroup(pc); 2668 2669 ret = -EINVAL; 2670 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) 2671 goto unlock; 2672 2673 move_lock_page_cgroup(pc, &flags); 2674 2675 if (PageCgroupFileMapped(pc)) { 2676 /* Update mapped_file data for mem_cgroup */ 2677 preempt_disable(); 2678 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 2679 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 2680 preempt_enable(); 2681 } 2682 mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages); 2683 if (uncharge) 2684 /* This is not "cancel", but cancel_charge does all we need. */ 2685 __mem_cgroup_cancel_charge(from, nr_pages); 2686 2687 /* caller should have done css_get */ 2688 pc->mem_cgroup = to; 2689 mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages); 2690 /* 2691 * We charges against "to" which may not have any tasks. Then, "to" 2692 * can be under rmdir(). But in current implementation, caller of 2693 * this function is just force_empty() and move charge, so it's 2694 * guaranteed that "to" is never removed. So, we don't check rmdir 2695 * status here. 2696 */ 2697 move_unlock_page_cgroup(pc, &flags); 2698 ret = 0; 2699unlock: 2700 unlock_page_cgroup(pc); 2701 /* 2702 * check events 2703 */ 2704 memcg_check_events(to, page); 2705 memcg_check_events(from, page); 2706out: 2707 return ret; 2708} 2709 2710/* 2711 * move charges to its parent. 2712 */ 2713 2714static int mem_cgroup_move_parent(struct page *page, 2715 struct page_cgroup *pc, 2716 struct mem_cgroup *child, 2717 gfp_t gfp_mask) 2718{ 2719 struct cgroup *cg = child->css.cgroup; 2720 struct cgroup *pcg = cg->parent; 2721 struct mem_cgroup *parent; 2722 unsigned int nr_pages; 2723 unsigned long uninitialized_var(flags); 2724 int ret; 2725 2726 /* Is ROOT ? */ 2727 if (!pcg) 2728 return -EINVAL; 2729 2730 ret = -EBUSY; 2731 if (!get_page_unless_zero(page)) 2732 goto out; 2733 if (isolate_lru_page(page)) 2734 goto put; 2735 2736 nr_pages = hpage_nr_pages(page); 2737 2738 parent = mem_cgroup_from_cont(pcg); 2739 ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false); 2740 if (ret || !parent) 2741 goto put_back; 2742 2743 if (nr_pages > 1) 2744 flags = compound_lock_irqsave(page); 2745 2746 ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true); 2747 if (ret) 2748 __mem_cgroup_cancel_charge(parent, nr_pages); 2749 2750 if (nr_pages > 1) 2751 compound_unlock_irqrestore(page, flags); 2752put_back: 2753 putback_lru_page(page); 2754put: 2755 put_page(page); 2756out: 2757 return ret; 2758} 2759 2760/* 2761 * Charge the memory controller for page usage. 2762 * Return 2763 * 0 if the charge was successful 2764 * < 0 if the cgroup is over its limit 2765 */ 2766static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 2767 gfp_t gfp_mask, enum charge_type ctype) 2768{ 2769 struct mem_cgroup *memcg = NULL; 2770 unsigned int nr_pages = 1; 2771 struct page_cgroup *pc; 2772 bool oom = true; 2773 int ret; 2774 2775 if (PageTransHuge(page)) { 2776 nr_pages <<= compound_order(page); 2777 VM_BUG_ON(!PageTransHuge(page)); 2778 /* 2779 * Never OOM-kill a process for a huge page. The 2780 * fault handler will fall back to regular pages. 2781 */ 2782 oom = false; 2783 } 2784 2785 pc = lookup_page_cgroup(page); 2786 BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */ 2787 2788 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom); 2789 if (ret || !memcg) 2790 return ret; 2791 2792 __mem_cgroup_commit_charge(memcg, page, nr_pages, pc, ctype); 2793 return 0; 2794} 2795 2796int mem_cgroup_newpage_charge(struct page *page, 2797 struct mm_struct *mm, gfp_t gfp_mask) 2798{ 2799 if (mem_cgroup_disabled()) 2800 return 0; 2801 /* 2802 * If already mapped, we don't have to account. 2803 * If page cache, page->mapping has address_space. 2804 * But page->mapping may have out-of-use anon_vma pointer, 2805 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping 2806 * is NULL. 2807 */ 2808 if (page_mapped(page) || (page->mapping && !PageAnon(page))) 2809 return 0; 2810 if (unlikely(!mm)) 2811 mm = &init_mm; 2812 return mem_cgroup_charge_common(page, mm, gfp_mask, 2813 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2814} 2815 2816static void 2817__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2818 enum charge_type ctype); 2819 2820static void 2821__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *memcg, 2822 enum charge_type ctype) 2823{ 2824 struct page_cgroup *pc = lookup_page_cgroup(page); 2825 /* 2826 * In some case, SwapCache, FUSE(splice_buf->radixtree), the page 2827 * is already on LRU. It means the page may on some other page_cgroup's 2828 * LRU. Take care of it. 2829 */ 2830 mem_cgroup_lru_del_before_commit(page); 2831 __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype); 2832 mem_cgroup_lru_add_after_commit(page); 2833 return; 2834} 2835 2836int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 2837 gfp_t gfp_mask) 2838{ 2839 struct mem_cgroup *memcg = NULL; 2840 int ret; 2841 2842 if (mem_cgroup_disabled()) 2843 return 0; 2844 if (PageCompound(page)) 2845 return 0; 2846 2847 if (unlikely(!mm)) 2848 mm = &init_mm; 2849 2850 if (page_is_file_cache(page)) { 2851 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &memcg, true); 2852 if (ret || !memcg) 2853 return ret; 2854 2855 /* 2856 * FUSE reuses pages without going through the final 2857 * put that would remove them from the LRU list, make 2858 * sure that they get relinked properly. 2859 */ 2860 __mem_cgroup_commit_charge_lrucare(page, memcg, 2861 MEM_CGROUP_CHARGE_TYPE_CACHE); 2862 return ret; 2863 } 2864 /* shmem */ 2865 if (PageSwapCache(page)) { 2866 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg); 2867 if (!ret) 2868 __mem_cgroup_commit_charge_swapin(page, memcg, 2869 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2870 } else 2871 ret = mem_cgroup_charge_common(page, mm, gfp_mask, 2872 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2873 2874 return ret; 2875} 2876 2877/* 2878 * While swap-in, try_charge -> commit or cancel, the page is locked. 2879 * And when try_charge() successfully returns, one refcnt to memcg without 2880 * struct page_cgroup is acquired. This refcnt will be consumed by 2881 * "commit()" or removed by "cancel()" 2882 */ 2883int mem_cgroup_try_charge_swapin(struct mm_struct *mm, 2884 struct page *page, 2885 gfp_t mask, struct mem_cgroup **ptr) 2886{ 2887 struct mem_cgroup *memcg; 2888 int ret; 2889 2890 *ptr = NULL; 2891 2892 if (mem_cgroup_disabled()) 2893 return 0; 2894 2895 if (!do_swap_account) 2896 goto charge_cur_mm; 2897 /* 2898 * A racing thread's fault, or swapoff, may have already updated 2899 * the pte, and even removed page from swap cache: in those cases 2900 * do_swap_page()'s pte_same() test will fail; but there's also a 2901 * KSM case which does need to charge the page. 2902 */ 2903 if (!PageSwapCache(page)) 2904 goto charge_cur_mm; 2905 memcg = try_get_mem_cgroup_from_page(page); 2906 if (!memcg) 2907 goto charge_cur_mm; 2908 *ptr = memcg; 2909 ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true); 2910 css_put(&memcg->css); 2911 return ret; 2912charge_cur_mm: 2913 if (unlikely(!mm)) 2914 mm = &init_mm; 2915 return __mem_cgroup_try_charge(mm, mask, 1, ptr, true); 2916} 2917 2918static void 2919__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2920 enum charge_type ctype) 2921{ 2922 if (mem_cgroup_disabled()) 2923 return; 2924 if (!ptr) 2925 return; 2926 cgroup_exclude_rmdir(&ptr->css); 2927 2928 __mem_cgroup_commit_charge_lrucare(page, ptr, ctype); 2929 /* 2930 * Now swap is on-memory. This means this page may be 2931 * counted both as mem and swap....double count. 2932 * Fix it by uncharging from memsw. Basically, this SwapCache is stable 2933 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() 2934 * may call delete_from_swap_cache() before reach here. 2935 */ 2936 if (do_swap_account && PageSwapCache(page)) { 2937 swp_entry_t ent = {.val = page_private(page)}; 2938 unsigned short id; 2939 struct mem_cgroup *memcg; 2940 2941 id = swap_cgroup_record(ent, 0); 2942 rcu_read_lock(); 2943 memcg = mem_cgroup_lookup(id); 2944 if (memcg) { 2945 /* 2946 * This recorded memcg can be obsolete one. So, avoid 2947 * calling css_tryget 2948 */ 2949 if (!mem_cgroup_is_root(memcg)) 2950 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 2951 mem_cgroup_swap_statistics(memcg, false); 2952 mem_cgroup_put(memcg); 2953 } 2954 rcu_read_unlock(); 2955 } 2956 /* 2957 * At swapin, we may charge account against cgroup which has no tasks. 2958 * So, rmdir()->pre_destroy() can be called while we do this charge. 2959 * In that case, we need to call pre_destroy() again. check it here. 2960 */ 2961 cgroup_release_and_wakeup_rmdir(&ptr->css); 2962} 2963 2964void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) 2965{ 2966 __mem_cgroup_commit_charge_swapin(page, ptr, 2967 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2968} 2969 2970void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg) 2971{ 2972 if (mem_cgroup_disabled()) 2973 return; 2974 if (!memcg) 2975 return; 2976 __mem_cgroup_cancel_charge(memcg, 1); 2977} 2978 2979static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg, 2980 unsigned int nr_pages, 2981 const enum charge_type ctype) 2982{ 2983 struct memcg_batch_info *batch = NULL; 2984 bool uncharge_memsw = true; 2985 2986 /* If swapout, usage of swap doesn't decrease */ 2987 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) 2988 uncharge_memsw = false; 2989 2990 batch = ¤t->memcg_batch; 2991 /* 2992 * In usual, we do css_get() when we remember memcg pointer. 2993 * But in this case, we keep res->usage until end of a series of 2994 * uncharges. Then, it's ok to ignore memcg's refcnt. 2995 */ 2996 if (!batch->memcg) 2997 batch->memcg = memcg; 2998 /* 2999 * do_batch > 0 when unmapping pages or inode invalidate/truncate. 3000 * In those cases, all pages freed continuously can be expected to be in 3001 * the same cgroup and we have chance to coalesce uncharges. 3002 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) 3003 * because we want to do uncharge as soon as possible. 3004 */ 3005 3006 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) 3007 goto direct_uncharge; 3008 3009 if (nr_pages > 1) 3010 goto direct_uncharge; 3011 3012 /* 3013 * In typical case, batch->memcg == mem. This means we can 3014 * merge a series of uncharges to an uncharge of res_counter. 3015 * If not, we uncharge res_counter ony by one. 3016 */ 3017 if (batch->memcg != memcg) 3018 goto direct_uncharge; 3019 /* remember freed charge and uncharge it later */ 3020 batch->nr_pages++; 3021 if (uncharge_memsw) 3022 batch->memsw_nr_pages++; 3023 return; 3024direct_uncharge: 3025 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE); 3026 if (uncharge_memsw) 3027 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE); 3028 if (unlikely(batch->memcg != memcg)) 3029 memcg_oom_recover(memcg); 3030 return; 3031} 3032 3033/* 3034 * uncharge if !page_mapped(page) 3035 */ 3036static struct mem_cgroup * 3037__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) 3038{ 3039 struct mem_cgroup *memcg = NULL; 3040 unsigned int nr_pages = 1; 3041 struct page_cgroup *pc; 3042 3043 if (mem_cgroup_disabled()) 3044 return NULL; 3045 3046 if (PageSwapCache(page)) 3047 return NULL; 3048 3049 if (PageTransHuge(page)) { 3050 nr_pages <<= compound_order(page); 3051 VM_BUG_ON(!PageTransHuge(page)); 3052 } 3053 /* 3054 * Check if our page_cgroup is valid 3055 */ 3056 pc = lookup_page_cgroup(page); 3057 if (unlikely(!pc || !PageCgroupUsed(pc))) 3058 return NULL; 3059 3060 lock_page_cgroup(pc); 3061 3062 memcg = pc->mem_cgroup; 3063 3064 if (!PageCgroupUsed(pc)) 3065 goto unlock_out; 3066 3067 switch (ctype) { 3068 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 3069 case MEM_CGROUP_CHARGE_TYPE_DROP: 3070 /* See mem_cgroup_prepare_migration() */ 3071 if (page_mapped(page) || PageCgroupMigration(pc)) 3072 goto unlock_out; 3073 break; 3074 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: 3075 if (!PageAnon(page)) { /* Shared memory */ 3076 if (page->mapping && !page_is_file_cache(page)) 3077 goto unlock_out; 3078 } else if (page_mapped(page)) /* Anon */ 3079 goto unlock_out; 3080 break; 3081 default: 3082 break; 3083 } 3084 3085 mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -nr_pages); 3086 3087 ClearPageCgroupUsed(pc); 3088 /* 3089 * pc->mem_cgroup is not cleared here. It will be accessed when it's 3090 * freed from LRU. This is safe because uncharged page is expected not 3091 * to be reused (freed soon). Exception is SwapCache, it's handled by 3092 * special functions. 3093 */ 3094 3095 unlock_page_cgroup(pc); 3096 /* 3097 * even after unlock, we have memcg->res.usage here and this memcg 3098 * will never be freed. 3099 */ 3100 memcg_check_events(memcg, page); 3101 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { 3102 mem_cgroup_swap_statistics(memcg, true); 3103 mem_cgroup_get(memcg); 3104 } 3105 if (!mem_cgroup_is_root(memcg)) 3106 mem_cgroup_do_uncharge(memcg, nr_pages, ctype); 3107 3108 return memcg; 3109 3110unlock_out: 3111 unlock_page_cgroup(pc); 3112 return NULL; 3113} 3114 3115void mem_cgroup_uncharge_page(struct page *page) 3116{ 3117 /* early check. */ 3118 if (page_mapped(page)) 3119 return; 3120 if (page->mapping && !PageAnon(page)) 3121 return; 3122 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); 3123} 3124 3125void mem_cgroup_uncharge_cache_page(struct page *page) 3126{ 3127 VM_BUG_ON(page_mapped(page)); 3128 VM_BUG_ON(page->mapping); 3129 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); 3130} 3131 3132/* 3133 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. 3134 * In that cases, pages are freed continuously and we can expect pages 3135 * are in the same memcg. All these calls itself limits the number of 3136 * pages freed at once, then uncharge_start/end() is called properly. 3137 * This may be called prural(2) times in a context, 3138 */ 3139 3140void mem_cgroup_uncharge_start(void) 3141{ 3142 current->memcg_batch.do_batch++; 3143 /* We can do nest. */ 3144 if (current->memcg_batch.do_batch == 1) { 3145 current->memcg_batch.memcg = NULL; 3146 current->memcg_batch.nr_pages = 0; 3147 current->memcg_batch.memsw_nr_pages = 0; 3148 } 3149} 3150 3151void mem_cgroup_uncharge_end(void) 3152{ 3153 struct memcg_batch_info *batch = ¤t->memcg_batch; 3154 3155 if (!batch->do_batch) 3156 return; 3157 3158 batch->do_batch--; 3159 if (batch->do_batch) /* If stacked, do nothing. */ 3160 return; 3161 3162 if (!batch->memcg) 3163 return; 3164 /* 3165 * This "batch->memcg" is valid without any css_get/put etc... 3166 * bacause we hide charges behind us. 3167 */ 3168 if (batch->nr_pages) 3169 res_counter_uncharge(&batch->memcg->res, 3170 batch->nr_pages * PAGE_SIZE); 3171 if (batch->memsw_nr_pages) 3172 res_counter_uncharge(&batch->memcg->memsw, 3173 batch->memsw_nr_pages * PAGE_SIZE); 3174 memcg_oom_recover(batch->memcg); 3175 /* forget this pointer (for sanity check) */ 3176 batch->memcg = NULL; 3177} 3178 3179#ifdef CONFIG_SWAP 3180/* 3181 * called after __delete_from_swap_cache() and drop "page" account. 3182 * memcg information is recorded to swap_cgroup of "ent" 3183 */ 3184void 3185mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 3186{ 3187 struct mem_cgroup *memcg; 3188 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; 3189 3190 if (!swapout) /* this was a swap cache but the swap is unused ! */ 3191 ctype = MEM_CGROUP_CHARGE_TYPE_DROP; 3192 3193 memcg = __mem_cgroup_uncharge_common(page, ctype); 3194 3195 /* 3196 * record memcg information, if swapout && memcg != NULL, 3197 * mem_cgroup_get() was called in uncharge(). 3198 */ 3199 if (do_swap_account && swapout && memcg) 3200 swap_cgroup_record(ent, css_id(&memcg->css)); 3201} 3202#endif 3203 3204#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 3205/* 3206 * called from swap_entry_free(). remove record in swap_cgroup and 3207 * uncharge "memsw" account. 3208 */ 3209void mem_cgroup_uncharge_swap(swp_entry_t ent) 3210{ 3211 struct mem_cgroup *memcg; 3212 unsigned short id; 3213 3214 if (!do_swap_account) 3215 return; 3216 3217 id = swap_cgroup_record(ent, 0); 3218 rcu_read_lock(); 3219 memcg = mem_cgroup_lookup(id); 3220 if (memcg) { 3221 /* 3222 * We uncharge this because swap is freed. 3223 * This memcg can be obsolete one. We avoid calling css_tryget 3224 */ 3225 if (!mem_cgroup_is_root(memcg)) 3226 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 3227 mem_cgroup_swap_statistics(memcg, false); 3228 mem_cgroup_put(memcg); 3229 } 3230 rcu_read_unlock(); 3231} 3232 3233/** 3234 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. 3235 * @entry: swap entry to be moved 3236 * @from: mem_cgroup which the entry is moved from 3237 * @to: mem_cgroup which the entry is moved to 3238 * @need_fixup: whether we should fixup res_counters and refcounts. 3239 * 3240 * It succeeds only when the swap_cgroup's record for this entry is the same 3241 * as the mem_cgroup's id of @from. 3242 * 3243 * Returns 0 on success, -EINVAL on failure. 3244 * 3245 * The caller must have charged to @to, IOW, called res_counter_charge() about 3246 * both res and memsw, and called css_get(). 3247 */ 3248static int mem_cgroup_move_swap_account(swp_entry_t entry, 3249 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 3250{ 3251 unsigned short old_id, new_id; 3252 3253 old_id = css_id(&from->css); 3254 new_id = css_id(&to->css); 3255 3256 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { 3257 mem_cgroup_swap_statistics(from, false); 3258 mem_cgroup_swap_statistics(to, true); 3259 /* 3260 * This function is only called from task migration context now. 3261 * It postpones res_counter and refcount handling till the end 3262 * of task migration(mem_cgroup_clear_mc()) for performance 3263 * improvement. But we cannot postpone mem_cgroup_get(to) 3264 * because if the process that has been moved to @to does 3265 * swap-in, the refcount of @to might be decreased to 0. 3266 */ 3267 mem_cgroup_get(to); 3268 if (need_fixup) { 3269 if (!mem_cgroup_is_root(from)) 3270 res_counter_uncharge(&from->memsw, PAGE_SIZE); 3271 mem_cgroup_put(from); 3272 /* 3273 * we charged both to->res and to->memsw, so we should 3274 * uncharge to->res. 3275 */ 3276 if (!mem_cgroup_is_root(to)) 3277 res_counter_uncharge(&to->res, PAGE_SIZE); 3278 } 3279 return 0; 3280 } 3281 return -EINVAL; 3282} 3283#else 3284static inline int mem_cgroup_move_swap_account(swp_entry_t entry, 3285 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 3286{ 3287 return -EINVAL; 3288} 3289#endif 3290 3291/* 3292 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old 3293 * page belongs to. 3294 */ 3295int mem_cgroup_prepare_migration(struct page *page, 3296 struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask) 3297{ 3298 struct mem_cgroup *memcg = NULL; 3299 struct page_cgroup *pc; 3300 enum charge_type ctype; 3301 int ret = 0; 3302 3303 *ptr = NULL; 3304 3305 VM_BUG_ON(PageTransHuge(page)); 3306 if (mem_cgroup_disabled()) 3307 return 0; 3308 3309 pc = lookup_page_cgroup(page); 3310 lock_page_cgroup(pc); 3311 if (PageCgroupUsed(pc)) { 3312 memcg = pc->mem_cgroup; 3313 css_get(&memcg->css); 3314 /* 3315 * At migrating an anonymous page, its mapcount goes down 3316 * to 0 and uncharge() will be called. But, even if it's fully 3317 * unmapped, migration may fail and this page has to be 3318 * charged again. We set MIGRATION flag here and delay uncharge 3319 * until end_migration() is called 3320 * 3321 * Corner Case Thinking 3322 * A) 3323 * When the old page was mapped as Anon and it's unmap-and-freed 3324 * while migration was ongoing. 3325 * If unmap finds the old page, uncharge() of it will be delayed 3326 * until end_migration(). If unmap finds a new page, it's 3327 * uncharged when it make mapcount to be 1->0. If unmap code 3328 * finds swap_migration_entry, the new page will not be mapped 3329 * and end_migration() will find it(mapcount==0). 3330 * 3331 * B) 3332 * When the old page was mapped but migraion fails, the kernel 3333 * remaps it. A charge for it is kept by MIGRATION flag even 3334 * if mapcount goes down to 0. We can do remap successfully 3335 * without charging it again. 3336 * 3337 * C) 3338 * The "old" page is under lock_page() until the end of 3339 * migration, so, the old page itself will not be swapped-out. 3340 * If the new page is swapped out before end_migraton, our 3341 * hook to usual swap-out path will catch the event. 3342 */ 3343 if (PageAnon(page)) 3344 SetPageCgroupMigration(pc); 3345 } 3346 unlock_page_cgroup(pc); 3347 /* 3348 * If the page is not charged at this point, 3349 * we return here. 3350 */ 3351 if (!memcg) 3352 return 0; 3353 3354 *ptr = memcg; 3355 ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false); 3356 css_put(&memcg->css);/* drop extra refcnt */ 3357 if (ret || *ptr == NULL) { 3358 if (PageAnon(page)) { 3359 lock_page_cgroup(pc); 3360 ClearPageCgroupMigration(pc); 3361 unlock_page_cgroup(pc); 3362 /* 3363 * The old page may be fully unmapped while we kept it. 3364 */ 3365 mem_cgroup_uncharge_page(page); 3366 } 3367 return -ENOMEM; 3368 } 3369 /* 3370 * We charge new page before it's used/mapped. So, even if unlock_page() 3371 * is called before end_migration, we can catch all events on this new 3372 * page. In the case new page is migrated but not remapped, new page's 3373 * mapcount will be finally 0 and we call uncharge in end_migration(). 3374 */ 3375 pc = lookup_page_cgroup(newpage); 3376 if (PageAnon(page)) 3377 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; 3378 else if (page_is_file_cache(page)) 3379 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; 3380 else 3381 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; 3382 __mem_cgroup_commit_charge(memcg, page, 1, pc, ctype); 3383 return ret; 3384} 3385 3386/* remove redundant charge if migration failed*/ 3387void mem_cgroup_end_migration(struct mem_cgroup *memcg, 3388 struct page *oldpage, struct page *newpage, bool migration_ok) 3389{ 3390 struct page *used, *unused; 3391 struct page_cgroup *pc; 3392 3393 if (!memcg) 3394 return; 3395 /* blocks rmdir() */ 3396 cgroup_exclude_rmdir(&memcg->css); 3397 if (!migration_ok) { 3398 used = oldpage; 3399 unused = newpage; 3400 } else { 3401 used = newpage; 3402 unused = oldpage; 3403 } 3404 /* 3405 * We disallowed uncharge of pages under migration because mapcount 3406 * of the page goes down to zero, temporarly. 3407 * Clear the flag and check the page should be charged. 3408 */ 3409 pc = lookup_page_cgroup(oldpage); 3410 lock_page_cgroup(pc); 3411 ClearPageCgroupMigration(pc); 3412 unlock_page_cgroup(pc); 3413 3414 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE); 3415 3416 /* 3417 * If a page is a file cache, radix-tree replacement is very atomic 3418 * and we can skip this check. When it was an Anon page, its mapcount 3419 * goes down to 0. But because we added MIGRATION flage, it's not 3420 * uncharged yet. There are several case but page->mapcount check 3421 * and USED bit check in mem_cgroup_uncharge_page() will do enough 3422 * check. (see prepare_charge() also) 3423 */ 3424 if (PageAnon(used)) 3425 mem_cgroup_uncharge_page(used); 3426 /* 3427 * At migration, we may charge account against cgroup which has no 3428 * tasks. 3429 * So, rmdir()->pre_destroy() can be called while we do this charge. 3430 * In that case, we need to call pre_destroy() again. check it here. 3431 */ 3432 cgroup_release_and_wakeup_rmdir(&memcg->css); 3433} 3434 3435/* 3436 * At replace page cache, newpage is not under any memcg but it's on 3437 * LRU. So, this function doesn't touch res_counter but handles LRU 3438 * in correct way. Both pages are locked so we cannot race with uncharge. 3439 */ 3440void mem_cgroup_replace_page_cache(struct page *oldpage, 3441 struct page *newpage) 3442{ 3443 struct mem_cgroup *memcg; 3444 struct page_cgroup *pc; 3445 struct zone *zone; 3446 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE; 3447 unsigned long flags; 3448 3449 if (mem_cgroup_disabled()) 3450 return; 3451 3452 pc = lookup_page_cgroup(oldpage); 3453 /* fix accounting on old pages */ 3454 lock_page_cgroup(pc); 3455 memcg = pc->mem_cgroup; 3456 mem_cgroup_charge_statistics(memcg, PageCgroupCache(pc), -1); 3457 ClearPageCgroupUsed(pc); 3458 unlock_page_cgroup(pc); 3459 3460 if (PageSwapBacked(oldpage)) 3461 type = MEM_CGROUP_CHARGE_TYPE_SHMEM; 3462 3463 zone = page_zone(newpage); 3464 pc = lookup_page_cgroup(newpage); 3465 /* 3466 * Even if newpage->mapping was NULL before starting replacement, 3467 * the newpage may be on LRU(or pagevec for LRU) already. We lock 3468 * LRU while we overwrite pc->mem_cgroup. 3469 */ 3470 spin_lock_irqsave(&zone->lru_lock, flags); 3471 if (PageLRU(newpage)) 3472 del_page_from_lru_list(zone, newpage, page_lru(newpage)); 3473 __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type); 3474 if (PageLRU(newpage)) 3475 add_page_to_lru_list(zone, newpage, page_lru(newpage)); 3476 spin_unlock_irqrestore(&zone->lru_lock, flags); 3477} 3478 3479#ifdef CONFIG_DEBUG_VM 3480static struct page_cgroup *lookup_page_cgroup_used(struct page *page) 3481{ 3482 struct page_cgroup *pc; 3483 3484 pc = lookup_page_cgroup(page); 3485 if (likely(pc) && PageCgroupUsed(pc)) 3486 return pc; 3487 return NULL; 3488} 3489 3490bool mem_cgroup_bad_page_check(struct page *page) 3491{ 3492 if (mem_cgroup_disabled()) 3493 return false; 3494 3495 return lookup_page_cgroup_used(page) != NULL; 3496} 3497 3498void mem_cgroup_print_bad_page(struct page *page) 3499{ 3500 struct page_cgroup *pc; 3501 3502 pc = lookup_page_cgroup_used(page); 3503 if (pc) { 3504 int ret = -1; 3505 char *path; 3506 3507 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p", 3508 pc, pc->flags, pc->mem_cgroup); 3509 3510 path = kmalloc(PATH_MAX, GFP_KERNEL); 3511 if (path) { 3512 rcu_read_lock(); 3513 ret = cgroup_path(pc->mem_cgroup->css.cgroup, 3514 path, PATH_MAX); 3515 rcu_read_unlock(); 3516 } 3517 3518 printk(KERN_CONT "(%s)\n", 3519 (ret < 0) ? "cannot get the path" : path); 3520 kfree(path); 3521 } 3522} 3523#endif 3524 3525static DEFINE_MUTEX(set_limit_mutex); 3526 3527static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, 3528 unsigned long long val) 3529{ 3530 int retry_count; 3531 u64 memswlimit, memlimit; 3532 int ret = 0; 3533 int children = mem_cgroup_count_children(memcg); 3534 u64 curusage, oldusage; 3535 int enlarge; 3536 3537 /* 3538 * For keeping hierarchical_reclaim simple, how long we should retry 3539 * is depends on callers. We set our retry-count to be function 3540 * of # of children which we should visit in this loop. 3541 */ 3542 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; 3543 3544 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); 3545 3546 enlarge = 0; 3547 while (retry_count) { 3548 if (signal_pending(current)) { 3549 ret = -EINTR; 3550 break; 3551 } 3552 /* 3553 * Rather than hide all in some function, I do this in 3554 * open coded manner. You see what this really does. 3555 * We have to guarantee memcg->res.limit < memcg->memsw.limit. 3556 */ 3557 mutex_lock(&set_limit_mutex); 3558 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3559 if (memswlimit < val) { 3560 ret = -EINVAL; 3561 mutex_unlock(&set_limit_mutex); 3562 break; 3563 } 3564 3565 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3566 if (memlimit < val) 3567 enlarge = 1; 3568 3569 ret = res_counter_set_limit(&memcg->res, val); 3570 if (!ret) { 3571 if (memswlimit == val) 3572 memcg->memsw_is_minimum = true; 3573 else 3574 memcg->memsw_is_minimum = false; 3575 } 3576 mutex_unlock(&set_limit_mutex); 3577 3578 if (!ret) 3579 break; 3580 3581 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 3582 MEM_CGROUP_RECLAIM_SHRINK, 3583 NULL); 3584 curusage = res_counter_read_u64(&memcg->res, RES_USAGE); 3585 /* Usage is reduced ? */ 3586 if (curusage >= oldusage) 3587 retry_count--; 3588 else 3589 oldusage = curusage; 3590 } 3591 if (!ret && enlarge) 3592 memcg_oom_recover(memcg); 3593 3594 return ret; 3595} 3596 3597static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, 3598 unsigned long long val) 3599{ 3600 int retry_count; 3601 u64 memlimit, memswlimit, oldusage, curusage; 3602 int children = mem_cgroup_count_children(memcg); 3603 int ret = -EBUSY; 3604 int enlarge = 0; 3605 3606 /* see mem_cgroup_resize_res_limit */ 3607 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; 3608 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 3609 while (retry_count) { 3610 if (signal_pending(current)) { 3611 ret = -EINTR; 3612 break; 3613 } 3614 /* 3615 * Rather than hide all in some function, I do this in 3616 * open coded manner. You see what this really does. 3617 * We have to guarantee memcg->res.limit < memcg->memsw.limit. 3618 */ 3619 mutex_lock(&set_limit_mutex); 3620 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3621 if (memlimit > val) { 3622 ret = -EINVAL; 3623 mutex_unlock(&set_limit_mutex); 3624 break; 3625 } 3626 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3627 if (memswlimit < val) 3628 enlarge = 1; 3629 ret = res_counter_set_limit(&memcg->memsw, val); 3630 if (!ret) { 3631 if (memlimit == val) 3632 memcg->memsw_is_minimum = true; 3633 else 3634 memcg->memsw_is_minimum = false; 3635 } 3636 mutex_unlock(&set_limit_mutex); 3637 3638 if (!ret) 3639 break; 3640 3641 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 3642 MEM_CGROUP_RECLAIM_NOSWAP | 3643 MEM_CGROUP_RECLAIM_SHRINK, 3644 NULL); 3645 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 3646 /* Usage is reduced ? */ 3647 if (curusage >= oldusage) 3648 retry_count--; 3649 else 3650 oldusage = curusage; 3651 } 3652 if (!ret && enlarge) 3653 memcg_oom_recover(memcg); 3654 return ret; 3655} 3656 3657unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 3658 gfp_t gfp_mask, 3659 unsigned long *total_scanned) 3660{ 3661 unsigned long nr_reclaimed = 0; 3662 struct mem_cgroup_per_zone *mz, *next_mz = NULL; 3663 unsigned long reclaimed; 3664 int loop = 0; 3665 struct mem_cgroup_tree_per_zone *mctz; 3666 unsigned long long excess; 3667 unsigned long nr_scanned; 3668 3669 if (order > 0) 3670 return 0; 3671 3672 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); 3673 /* 3674 * This loop can run a while, specially if mem_cgroup's continuously 3675 * keep exceeding their soft limit and putting the system under 3676 * pressure 3677 */ 3678 do { 3679 if (next_mz) 3680 mz = next_mz; 3681 else 3682 mz = mem_cgroup_largest_soft_limit_node(mctz); 3683 if (!mz) 3684 break; 3685 3686 nr_scanned = 0; 3687 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone, 3688 gfp_mask, 3689 MEM_CGROUP_RECLAIM_SOFT, 3690 &nr_scanned); 3691 nr_reclaimed += reclaimed; 3692 *total_scanned += nr_scanned; 3693 spin_lock(&mctz->lock); 3694 3695 /* 3696 * If we failed to reclaim anything from this memory cgroup 3697 * it is time to move on to the next cgroup 3698 */ 3699 next_mz = NULL; 3700 if (!reclaimed) { 3701 do { 3702 /* 3703 * Loop until we find yet another one. 3704 * 3705 * By the time we get the soft_limit lock 3706 * again, someone might have aded the 3707 * group back on the RB tree. Iterate to 3708 * make sure we get a different mem. 3709 * mem_cgroup_largest_soft_limit_node returns 3710 * NULL if no other cgroup is present on 3711 * the tree 3712 */ 3713 next_mz = 3714 __mem_cgroup_largest_soft_limit_node(mctz); 3715 if (next_mz == mz) 3716 css_put(&next_mz->mem->css); 3717 else /* next_mz == NULL or other memcg */ 3718 break; 3719 } while (1); 3720 } 3721 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 3722 excess = res_counter_soft_limit_excess(&mz->mem->res); 3723 /* 3724 * One school of thought says that we should not add 3725 * back the node to the tree if reclaim returns 0. 3726 * But our reclaim could return 0, simply because due 3727 * to priority we are exposing a smaller subset of 3728 * memory to reclaim from. Consider this as a longer 3729 * term TODO. 3730 */ 3731 /* If excess == 0, no tree ops */ 3732 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess); 3733 spin_unlock(&mctz->lock); 3734 css_put(&mz->mem->css); 3735 loop++; 3736 /* 3737 * Could not reclaim anything and there are no more 3738 * mem cgroups to try or we seem to be looping without 3739 * reclaiming anything. 3740 */ 3741 if (!nr_reclaimed && 3742 (next_mz == NULL || 3743 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) 3744 break; 3745 } while (!nr_reclaimed); 3746 if (next_mz) 3747 css_put(&next_mz->mem->css); 3748 return nr_reclaimed; 3749} 3750 3751/* 3752 * This routine traverse page_cgroup in given list and drop them all. 3753 * *And* this routine doesn't reclaim page itself, just removes page_cgroup. 3754 */ 3755static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg, 3756 int node, int zid, enum lru_list lru) 3757{ 3758 struct zone *zone; 3759 struct mem_cgroup_per_zone *mz; 3760 struct page_cgroup *pc, *busy; 3761 unsigned long flags, loop; 3762 struct list_head *list; 3763 int ret = 0; 3764 3765 zone = &NODE_DATA(node)->node_zones[zid]; 3766 mz = mem_cgroup_zoneinfo(memcg, node, zid); 3767 list = &mz->lists[lru]; 3768 3769 loop = MEM_CGROUP_ZSTAT(mz, lru); 3770 /* give some margin against EBUSY etc...*/ 3771 loop += 256; 3772 busy = NULL; 3773 while (loop--) { 3774 struct page *page; 3775 3776 ret = 0; 3777 spin_lock_irqsave(&zone->lru_lock, flags); 3778 if (list_empty(list)) { 3779 spin_unlock_irqrestore(&zone->lru_lock, flags); 3780 break; 3781 } 3782 pc = list_entry(list->prev, struct page_cgroup, lru); 3783 if (busy == pc) { 3784 list_move(&pc->lru, list); 3785 busy = NULL; 3786 spin_unlock_irqrestore(&zone->lru_lock, flags); 3787 continue; 3788 } 3789 spin_unlock_irqrestore(&zone->lru_lock, flags); 3790 3791 page = lookup_cgroup_page(pc); 3792 3793 ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL); 3794 if (ret == -ENOMEM) 3795 break; 3796 3797 if (ret == -EBUSY || ret == -EINVAL) { 3798 /* found lock contention or "pc" is obsolete. */ 3799 busy = pc; 3800 cond_resched(); 3801 } else 3802 busy = NULL; 3803 } 3804 3805 if (!ret && !list_empty(list)) 3806 return -EBUSY; 3807 return ret; 3808} 3809 3810/* 3811 * make mem_cgroup's charge to be 0 if there is no task. 3812 * This enables deleting this mem_cgroup. 3813 */ 3814static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all) 3815{ 3816 int ret; 3817 int node, zid, shrink; 3818 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 3819 struct cgroup *cgrp = memcg->css.cgroup; 3820 3821 css_get(&memcg->css); 3822 3823 shrink = 0; 3824 /* should free all ? */ 3825 if (free_all) 3826 goto try_to_free; 3827move_account: 3828 do { 3829 ret = -EBUSY; 3830 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) 3831 goto out; 3832 ret = -EINTR; 3833 if (signal_pending(current)) 3834 goto out; 3835 /* This is for making all *used* pages to be on LRU. */ 3836 lru_add_drain_all(); 3837 drain_all_stock_sync(memcg); 3838 ret = 0; 3839 mem_cgroup_start_move(memcg); 3840 for_each_node_state(node, N_HIGH_MEMORY) { 3841 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { 3842 enum lru_list l; 3843 for_each_lru(l) { 3844 ret = mem_cgroup_force_empty_list(memcg, 3845 node, zid, l); 3846 if (ret) 3847 break; 3848 } 3849 } 3850 if (ret) 3851 break; 3852 } 3853 mem_cgroup_end_move(memcg); 3854 memcg_oom_recover(memcg); 3855 /* it seems parent cgroup doesn't have enough mem */ 3856 if (ret == -ENOMEM) 3857 goto try_to_free; 3858 cond_resched(); 3859 /* "ret" should also be checked to ensure all lists are empty. */ 3860 } while (memcg->res.usage > 0 || ret); 3861out: 3862 css_put(&memcg->css); 3863 return ret; 3864 3865try_to_free: 3866 /* returns EBUSY if there is a task or if we come here twice. */ 3867 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { 3868 ret = -EBUSY; 3869 goto out; 3870 } 3871 /* we call try-to-free pages for make this cgroup empty */ 3872 lru_add_drain_all(); 3873 /* try to free all pages in this cgroup */ 3874 shrink = 1; 3875 while (nr_retries && memcg->res.usage > 0) { 3876 int progress; 3877 3878 if (signal_pending(current)) { 3879 ret = -EINTR; 3880 goto out; 3881 } 3882 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL, 3883 false); 3884 if (!progress) { 3885 nr_retries--; 3886 /* maybe some writeback is necessary */ 3887 congestion_wait(BLK_RW_ASYNC, HZ/10); 3888 } 3889 3890 } 3891 lru_add_drain(); 3892 /* try move_account...there may be some *locked* pages. */ 3893 goto move_account; 3894} 3895 3896int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) 3897{ 3898 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); 3899} 3900 3901 3902static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) 3903{ 3904 return mem_cgroup_from_cont(cont)->use_hierarchy; 3905} 3906 3907static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, 3908 u64 val) 3909{ 3910 int retval = 0; 3911 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 3912 struct cgroup *parent = cont->parent; 3913 struct mem_cgroup *parent_memcg = NULL; 3914 3915 if (parent) 3916 parent_memcg = mem_cgroup_from_cont(parent); 3917 3918 cgroup_lock(); 3919 /* 3920 * If parent's use_hierarchy is set, we can't make any modifications 3921 * in the child subtrees. If it is unset, then the change can 3922 * occur, provided the current cgroup has no children. 3923 * 3924 * For the root cgroup, parent_mem is NULL, we allow value to be 3925 * set if there are no children. 3926 */ 3927 if ((!parent_memcg || !parent_memcg->use_hierarchy) && 3928 (val == 1 || val == 0)) { 3929 if (list_empty(&cont->children)) 3930 memcg->use_hierarchy = val; 3931 else 3932 retval = -EBUSY; 3933 } else 3934 retval = -EINVAL; 3935 cgroup_unlock(); 3936 3937 return retval; 3938} 3939 3940 3941static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg, 3942 enum mem_cgroup_stat_index idx) 3943{ 3944 struct mem_cgroup *iter; 3945 long val = 0; 3946 3947 /* Per-cpu values can be negative, use a signed accumulator */ 3948 for_each_mem_cgroup_tree(iter, memcg) 3949 val += mem_cgroup_read_stat(iter, idx); 3950 3951 if (val < 0) /* race ? */ 3952 val = 0; 3953 return val; 3954} 3955 3956static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap) 3957{ 3958 u64 val; 3959 3960 if (!mem_cgroup_is_root(memcg)) { 3961 if (!swap) 3962 return res_counter_read_u64(&memcg->res, RES_USAGE); 3963 else 3964 return res_counter_read_u64(&memcg->memsw, RES_USAGE); 3965 } 3966 3967 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE); 3968 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS); 3969 3970 if (swap) 3971 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAPOUT); 3972 3973 return val << PAGE_SHIFT; 3974} 3975 3976static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 3977{ 3978 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 3979 u64 val; 3980 int type, name; 3981 3982 type = MEMFILE_TYPE(cft->private); 3983 name = MEMFILE_ATTR(cft->private); 3984 switch (type) { 3985 case _MEM: 3986 if (name == RES_USAGE) 3987 val = mem_cgroup_usage(memcg, false); 3988 else 3989 val = res_counter_read_u64(&memcg->res, name); 3990 break; 3991 case _MEMSWAP: 3992 if (name == RES_USAGE) 3993 val = mem_cgroup_usage(memcg, true); 3994 else 3995 val = res_counter_read_u64(&memcg->memsw, name); 3996 break; 3997 default: 3998 BUG(); 3999 break; 4000 } 4001 return val; 4002} 4003/* 4004 * The user of this function is... 4005 * RES_LIMIT. 4006 */ 4007static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 4008 const char *buffer) 4009{ 4010 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 4011 int type, name; 4012 unsigned long long val; 4013 int ret; 4014 4015 type = MEMFILE_TYPE(cft->private); 4016 name = MEMFILE_ATTR(cft->private); 4017 switch (name) { 4018 case RES_LIMIT: 4019 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ 4020 ret = -EINVAL; 4021 break; 4022 } 4023 /* This function does all necessary parse...reuse it */ 4024 ret = res_counter_memparse_write_strategy(buffer, &val); 4025 if (ret) 4026 break; 4027 if (type == _MEM) 4028 ret = mem_cgroup_resize_limit(memcg, val); 4029 else 4030 ret = mem_cgroup_resize_memsw_limit(memcg, val); 4031 break; 4032 case RES_SOFT_LIMIT: 4033 ret = res_counter_memparse_write_strategy(buffer, &val); 4034 if (ret) 4035 break; 4036 /* 4037 * For memsw, soft limits are hard to implement in terms 4038 * of semantics, for now, we support soft limits for 4039 * control without swap 4040 */ 4041 if (type == _MEM) 4042 ret = res_counter_set_soft_limit(&memcg->res, val); 4043 else 4044 ret = -EINVAL; 4045 break; 4046 default: 4047 ret = -EINVAL; /* should be BUG() ? */ 4048 break; 4049 } 4050 return ret; 4051} 4052 4053static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 4054 unsigned long long *mem_limit, unsigned long long *memsw_limit) 4055{ 4056 struct cgroup *cgroup; 4057 unsigned long long min_limit, min_memsw_limit, tmp; 4058 4059 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 4060 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 4061 cgroup = memcg->css.cgroup; 4062 if (!memcg->use_hierarchy) 4063 goto out; 4064 4065 while (cgroup->parent) { 4066 cgroup = cgroup->parent; 4067 memcg = mem_cgroup_from_cont(cgroup); 4068 if (!memcg->use_hierarchy) 4069 break; 4070 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); 4071 min_limit = min(min_limit, tmp); 4072 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 4073 min_memsw_limit = min(min_memsw_limit, tmp); 4074 } 4075out: 4076 *mem_limit = min_limit; 4077 *memsw_limit = min_memsw_limit; 4078 return; 4079} 4080 4081static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) 4082{ 4083 struct mem_cgroup *memcg; 4084 int type, name; 4085 4086 memcg = mem_cgroup_from_cont(cont); 4087 type = MEMFILE_TYPE(event); 4088 name = MEMFILE_ATTR(event); 4089 switch (name) { 4090 case RES_MAX_USAGE: 4091 if (type == _MEM) 4092 res_counter_reset_max(&memcg->res); 4093 else 4094 res_counter_reset_max(&memcg->memsw); 4095 break; 4096 case RES_FAILCNT: 4097 if (type == _MEM) 4098 res_counter_reset_failcnt(&memcg->res); 4099 else 4100 res_counter_reset_failcnt(&memcg->memsw); 4101 break; 4102 } 4103 4104 return 0; 4105} 4106 4107static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, 4108 struct cftype *cft) 4109{ 4110 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; 4111} 4112 4113#ifdef CONFIG_MMU 4114static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 4115 struct cftype *cft, u64 val) 4116{ 4117 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4118 4119 if (val >= (1 << NR_MOVE_TYPE)) 4120 return -EINVAL; 4121 /* 4122 * We check this value several times in both in can_attach() and 4123 * attach(), so we need cgroup lock to prevent this value from being 4124 * inconsistent. 4125 */ 4126 cgroup_lock(); 4127 memcg->move_charge_at_immigrate = val; 4128 cgroup_unlock(); 4129 4130 return 0; 4131} 4132#else 4133static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 4134 struct cftype *cft, u64 val) 4135{ 4136 return -ENOSYS; 4137} 4138#endif 4139 4140 4141/* For read statistics */ 4142enum { 4143 MCS_CACHE, 4144 MCS_RSS, 4145 MCS_FILE_MAPPED, 4146 MCS_PGPGIN, 4147 MCS_PGPGOUT, 4148 MCS_SWAP, 4149 MCS_PGFAULT, 4150 MCS_PGMAJFAULT, 4151 MCS_INACTIVE_ANON, 4152 MCS_ACTIVE_ANON, 4153 MCS_INACTIVE_FILE, 4154 MCS_ACTIVE_FILE, 4155 MCS_UNEVICTABLE, 4156 NR_MCS_STAT, 4157}; 4158 4159struct mcs_total_stat { 4160 s64 stat[NR_MCS_STAT]; 4161}; 4162 4163struct { 4164 char *local_name; 4165 char *total_name; 4166} memcg_stat_strings[NR_MCS_STAT] = { 4167 {"cache", "total_cache"}, 4168 {"rss", "total_rss"}, 4169 {"mapped_file", "total_mapped_file"}, 4170 {"pgpgin", "total_pgpgin"}, 4171 {"pgpgout", "total_pgpgout"}, 4172 {"swap", "total_swap"}, 4173 {"pgfault", "total_pgfault"}, 4174 {"pgmajfault", "total_pgmajfault"}, 4175 {"inactive_anon", "total_inactive_anon"}, 4176 {"active_anon", "total_active_anon"}, 4177 {"inactive_file", "total_inactive_file"}, 4178 {"active_file", "total_active_file"}, 4179 {"unevictable", "total_unevictable"} 4180}; 4181 4182 4183static void 4184mem_cgroup_get_local_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s) 4185{ 4186 s64 val; 4187 4188 /* per cpu stat */ 4189 val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_CACHE); 4190 s->stat[MCS_CACHE] += val * PAGE_SIZE; 4191 val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_RSS); 4192 s->stat[MCS_RSS] += val * PAGE_SIZE; 4193 val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_FILE_MAPPED); 4194 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; 4195 val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGIN); 4196 s->stat[MCS_PGPGIN] += val; 4197 val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGPGOUT); 4198 s->stat[MCS_PGPGOUT] += val; 4199 if (do_swap_account) { 4200 val = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_SWAPOUT); 4201 s->stat[MCS_SWAP] += val * PAGE_SIZE; 4202 } 4203 val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGFAULT); 4204 s->stat[MCS_PGFAULT] += val; 4205 val = mem_cgroup_read_events(memcg, MEM_CGROUP_EVENTS_PGMAJFAULT); 4206 s->stat[MCS_PGMAJFAULT] += val; 4207 4208 /* per zone stat */ 4209 val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_ANON)); 4210 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; 4211 val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_ANON)); 4212 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; 4213 val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_INACTIVE_FILE)); 4214 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; 4215 val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_ACTIVE_FILE)); 4216 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; 4217 val = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE)); 4218 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; 4219} 4220 4221static void 4222mem_cgroup_get_total_stat(struct mem_cgroup *memcg, struct mcs_total_stat *s) 4223{ 4224 struct mem_cgroup *iter; 4225 4226 for_each_mem_cgroup_tree(iter, memcg) 4227 mem_cgroup_get_local_stat(iter, s); 4228} 4229 4230#ifdef CONFIG_NUMA 4231static int mem_control_numa_stat_show(struct seq_file *m, void *arg) 4232{ 4233 int nid; 4234 unsigned long total_nr, file_nr, anon_nr, unevictable_nr; 4235 unsigned long node_nr; 4236 struct cgroup *cont = m->private; 4237 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 4238 4239 total_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL); 4240 seq_printf(m, "total=%lu", total_nr); 4241 for_each_node_state(nid, N_HIGH_MEMORY) { 4242 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, LRU_ALL); 4243 seq_printf(m, " N%d=%lu", nid, node_nr); 4244 } 4245 seq_putc(m, '\n'); 4246 4247 file_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_FILE); 4248 seq_printf(m, "file=%lu", file_nr); 4249 for_each_node_state(nid, N_HIGH_MEMORY) { 4250 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, 4251 LRU_ALL_FILE); 4252 seq_printf(m, " N%d=%lu", nid, node_nr); 4253 } 4254 seq_putc(m, '\n'); 4255 4256 anon_nr = mem_cgroup_nr_lru_pages(mem_cont, LRU_ALL_ANON); 4257 seq_printf(m, "anon=%lu", anon_nr); 4258 for_each_node_state(nid, N_HIGH_MEMORY) { 4259 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, 4260 LRU_ALL_ANON); 4261 seq_printf(m, " N%d=%lu", nid, node_nr); 4262 } 4263 seq_putc(m, '\n'); 4264 4265 unevictable_nr = mem_cgroup_nr_lru_pages(mem_cont, BIT(LRU_UNEVICTABLE)); 4266 seq_printf(m, "unevictable=%lu", unevictable_nr); 4267 for_each_node_state(nid, N_HIGH_MEMORY) { 4268 node_nr = mem_cgroup_node_nr_lru_pages(mem_cont, nid, 4269 BIT(LRU_UNEVICTABLE)); 4270 seq_printf(m, " N%d=%lu", nid, node_nr); 4271 } 4272 seq_putc(m, '\n'); 4273 return 0; 4274} 4275#endif /* CONFIG_NUMA */ 4276 4277static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 4278 struct cgroup_map_cb *cb) 4279{ 4280 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 4281 struct mcs_total_stat mystat; 4282 int i; 4283 4284 memset(&mystat, 0, sizeof(mystat)); 4285 mem_cgroup_get_local_stat(mem_cont, &mystat); 4286 4287 4288 for (i = 0; i < NR_MCS_STAT; i++) { 4289 if (i == MCS_SWAP && !do_swap_account) 4290 continue; 4291 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); 4292 } 4293 4294 /* Hierarchical information */ 4295 { 4296 unsigned long long limit, memsw_limit; 4297 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); 4298 cb->fill(cb, "hierarchical_memory_limit", limit); 4299 if (do_swap_account) 4300 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); 4301 } 4302 4303 memset(&mystat, 0, sizeof(mystat)); 4304 mem_cgroup_get_total_stat(mem_cont, &mystat); 4305 for (i = 0; i < NR_MCS_STAT; i++) { 4306 if (i == MCS_SWAP && !do_swap_account) 4307 continue; 4308 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); 4309 } 4310 4311#ifdef CONFIG_DEBUG_VM 4312 { 4313 int nid, zid; 4314 struct mem_cgroup_per_zone *mz; 4315 unsigned long recent_rotated[2] = {0, 0}; 4316 unsigned long recent_scanned[2] = {0, 0}; 4317 4318 for_each_online_node(nid) 4319 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 4320 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 4321 4322 recent_rotated[0] += 4323 mz->reclaim_stat.recent_rotated[0]; 4324 recent_rotated[1] += 4325 mz->reclaim_stat.recent_rotated[1]; 4326 recent_scanned[0] += 4327 mz->reclaim_stat.recent_scanned[0]; 4328 recent_scanned[1] += 4329 mz->reclaim_stat.recent_scanned[1]; 4330 } 4331 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); 4332 cb->fill(cb, "recent_rotated_file", recent_rotated[1]); 4333 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); 4334 cb->fill(cb, "recent_scanned_file", recent_scanned[1]); 4335 } 4336#endif 4337 4338 return 0; 4339} 4340 4341static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) 4342{ 4343 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4344 4345 return mem_cgroup_swappiness(memcg); 4346} 4347 4348static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, 4349 u64 val) 4350{ 4351 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4352 struct mem_cgroup *parent; 4353 4354 if (val > 100) 4355 return -EINVAL; 4356 4357 if (cgrp->parent == NULL) 4358 return -EINVAL; 4359 4360 parent = mem_cgroup_from_cont(cgrp->parent); 4361 4362 cgroup_lock(); 4363 4364 /* If under hierarchy, only empty-root can set this value */ 4365 if ((parent->use_hierarchy) || 4366 (memcg->use_hierarchy && !list_empty(&cgrp->children))) { 4367 cgroup_unlock(); 4368 return -EINVAL; 4369 } 4370 4371 memcg->swappiness = val; 4372 4373 cgroup_unlock(); 4374 4375 return 0; 4376} 4377 4378static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) 4379{ 4380 struct mem_cgroup_threshold_ary *t; 4381 u64 usage; 4382 int i; 4383 4384 rcu_read_lock(); 4385 if (!swap) 4386 t = rcu_dereference(memcg->thresholds.primary); 4387 else 4388 t = rcu_dereference(memcg->memsw_thresholds.primary); 4389 4390 if (!t) 4391 goto unlock; 4392 4393 usage = mem_cgroup_usage(memcg, swap); 4394 4395 /* 4396 * current_threshold points to threshold just below usage. 4397 * If it's not true, a threshold was crossed after last 4398 * call of __mem_cgroup_threshold(). 4399 */ 4400 i = t->current_threshold; 4401 4402 /* 4403 * Iterate backward over array of thresholds starting from 4404 * current_threshold and check if a threshold is crossed. 4405 * If none of thresholds below usage is crossed, we read 4406 * only one element of the array here. 4407 */ 4408 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) 4409 eventfd_signal(t->entries[i].eventfd, 1); 4410 4411 /* i = current_threshold + 1 */ 4412 i++; 4413 4414 /* 4415 * Iterate forward over array of thresholds starting from 4416 * current_threshold+1 and check if a threshold is crossed. 4417 * If none of thresholds above usage is crossed, we read 4418 * only one element of the array here. 4419 */ 4420 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) 4421 eventfd_signal(t->entries[i].eventfd, 1); 4422 4423 /* Update current_threshold */ 4424 t->current_threshold = i - 1; 4425unlock: 4426 rcu_read_unlock(); 4427} 4428 4429static void mem_cgroup_threshold(struct mem_cgroup *memcg) 4430{ 4431 while (memcg) { 4432 __mem_cgroup_threshold(memcg, false); 4433 if (do_swap_account) 4434 __mem_cgroup_threshold(memcg, true); 4435 4436 memcg = parent_mem_cgroup(memcg); 4437 } 4438} 4439 4440static int compare_thresholds(const void *a, const void *b) 4441{ 4442 const struct mem_cgroup_threshold *_a = a; 4443 const struct mem_cgroup_threshold *_b = b; 4444 4445 return _a->threshold - _b->threshold; 4446} 4447 4448static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg) 4449{ 4450 struct mem_cgroup_eventfd_list *ev; 4451 4452 list_for_each_entry(ev, &memcg->oom_notify, list) 4453 eventfd_signal(ev->eventfd, 1); 4454 return 0; 4455} 4456 4457static void mem_cgroup_oom_notify(struct mem_cgroup *memcg) 4458{ 4459 struct mem_cgroup *iter; 4460 4461 for_each_mem_cgroup_tree(iter, memcg) 4462 mem_cgroup_oom_notify_cb(iter); 4463} 4464 4465static int mem_cgroup_usage_register_event(struct cgroup *cgrp, 4466 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 4467{ 4468 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4469 struct mem_cgroup_thresholds *thresholds; 4470 struct mem_cgroup_threshold_ary *new; 4471 int type = MEMFILE_TYPE(cft->private); 4472 u64 threshold, usage; 4473 int i, size, ret; 4474 4475 ret = res_counter_memparse_write_strategy(args, &threshold); 4476 if (ret) 4477 return ret; 4478 4479 mutex_lock(&memcg->thresholds_lock); 4480 4481 if (type == _MEM) 4482 thresholds = &memcg->thresholds; 4483 else if (type == _MEMSWAP) 4484 thresholds = &memcg->memsw_thresholds; 4485 else 4486 BUG(); 4487 4488 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 4489 4490 /* Check if a threshold crossed before adding a new one */ 4491 if (thresholds->primary) 4492 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 4493 4494 size = thresholds->primary ? thresholds->primary->size + 1 : 1; 4495 4496 /* Allocate memory for new array of thresholds */ 4497 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), 4498 GFP_KERNEL); 4499 if (!new) { 4500 ret = -ENOMEM; 4501 goto unlock; 4502 } 4503 new->size = size; 4504 4505 /* Copy thresholds (if any) to new array */ 4506 if (thresholds->primary) { 4507 memcpy(new->entries, thresholds->primary->entries, (size - 1) * 4508 sizeof(struct mem_cgroup_threshold)); 4509 } 4510 4511 /* Add new threshold */ 4512 new->entries[size - 1].eventfd = eventfd; 4513 new->entries[size - 1].threshold = threshold; 4514 4515 /* Sort thresholds. Registering of new threshold isn't time-critical */ 4516 sort(new->entries, size, sizeof(struct mem_cgroup_threshold), 4517 compare_thresholds, NULL); 4518 4519 /* Find current threshold */ 4520 new->current_threshold = -1; 4521 for (i = 0; i < size; i++) { 4522 if (new->entries[i].threshold < usage) { 4523 /* 4524 * new->current_threshold will not be used until 4525 * rcu_assign_pointer(), so it's safe to increment 4526 * it here. 4527 */ 4528 ++new->current_threshold; 4529 } 4530 } 4531 4532 /* Free old spare buffer and save old primary buffer as spare */ 4533 kfree(thresholds->spare); 4534 thresholds->spare = thresholds->primary; 4535 4536 rcu_assign_pointer(thresholds->primary, new); 4537 4538 /* To be sure that nobody uses thresholds */ 4539 synchronize_rcu(); 4540 4541unlock: 4542 mutex_unlock(&memcg->thresholds_lock); 4543 4544 return ret; 4545} 4546 4547static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, 4548 struct cftype *cft, struct eventfd_ctx *eventfd) 4549{ 4550 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4551 struct mem_cgroup_thresholds *thresholds; 4552 struct mem_cgroup_threshold_ary *new; 4553 int type = MEMFILE_TYPE(cft->private); 4554 u64 usage; 4555 int i, j, size; 4556 4557 mutex_lock(&memcg->thresholds_lock); 4558 if (type == _MEM) 4559 thresholds = &memcg->thresholds; 4560 else if (type == _MEMSWAP) 4561 thresholds = &memcg->memsw_thresholds; 4562 else 4563 BUG(); 4564 4565 /* 4566 * Something went wrong if we trying to unregister a threshold 4567 * if we don't have thresholds 4568 */ 4569 BUG_ON(!thresholds); 4570 4571 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 4572 4573 /* Check if a threshold crossed before removing */ 4574 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 4575 4576 /* Calculate new number of threshold */ 4577 size = 0; 4578 for (i = 0; i < thresholds->primary->size; i++) { 4579 if (thresholds->primary->entries[i].eventfd != eventfd) 4580 size++; 4581 } 4582 4583 new = thresholds->spare; 4584 4585 /* Set thresholds array to NULL if we don't have thresholds */ 4586 if (!size) { 4587 kfree(new); 4588 new = NULL; 4589 goto swap_buffers; 4590 } 4591 4592 new->size = size; 4593 4594 /* Copy thresholds and find current threshold */ 4595 new->current_threshold = -1; 4596 for (i = 0, j = 0; i < thresholds->primary->size; i++) { 4597 if (thresholds->primary->entries[i].eventfd == eventfd) 4598 continue; 4599 4600 new->entries[j] = thresholds->primary->entries[i]; 4601 if (new->entries[j].threshold < usage) { 4602 /* 4603 * new->current_threshold will not be used 4604 * until rcu_assign_pointer(), so it's safe to increment 4605 * it here. 4606 */ 4607 ++new->current_threshold; 4608 } 4609 j++; 4610 } 4611 4612swap_buffers: 4613 /* Swap primary and spare array */ 4614 thresholds->spare = thresholds->primary; 4615 rcu_assign_pointer(thresholds->primary, new); 4616 4617 /* To be sure that nobody uses thresholds */ 4618 synchronize_rcu(); 4619 4620 mutex_unlock(&memcg->thresholds_lock); 4621} 4622 4623static int mem_cgroup_oom_register_event(struct cgroup *cgrp, 4624 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 4625{ 4626 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4627 struct mem_cgroup_eventfd_list *event; 4628 int type = MEMFILE_TYPE(cft->private); 4629 4630 BUG_ON(type != _OOM_TYPE); 4631 event = kmalloc(sizeof(*event), GFP_KERNEL); 4632 if (!event) 4633 return -ENOMEM; 4634 4635 spin_lock(&memcg_oom_lock); 4636 4637 event->eventfd = eventfd; 4638 list_add(&event->list, &memcg->oom_notify); 4639 4640 /* already in OOM ? */ 4641 if (atomic_read(&memcg->under_oom)) 4642 eventfd_signal(eventfd, 1); 4643 spin_unlock(&memcg_oom_lock); 4644 4645 return 0; 4646} 4647 4648static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, 4649 struct cftype *cft, struct eventfd_ctx *eventfd) 4650{ 4651 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4652 struct mem_cgroup_eventfd_list *ev, *tmp; 4653 int type = MEMFILE_TYPE(cft->private); 4654 4655 BUG_ON(type != _OOM_TYPE); 4656 4657 spin_lock(&memcg_oom_lock); 4658 4659 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) { 4660 if (ev->eventfd == eventfd) { 4661 list_del(&ev->list); 4662 kfree(ev); 4663 } 4664 } 4665 4666 spin_unlock(&memcg_oom_lock); 4667} 4668 4669static int mem_cgroup_oom_control_read(struct cgroup *cgrp, 4670 struct cftype *cft, struct cgroup_map_cb *cb) 4671{ 4672 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4673 4674 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable); 4675 4676 if (atomic_read(&memcg->under_oom)) 4677 cb->fill(cb, "under_oom", 1); 4678 else 4679 cb->fill(cb, "under_oom", 0); 4680 return 0; 4681} 4682 4683static int mem_cgroup_oom_control_write(struct cgroup *cgrp, 4684 struct cftype *cft, u64 val) 4685{ 4686 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4687 struct mem_cgroup *parent; 4688 4689 /* cannot set to root cgroup and only 0 and 1 are allowed */ 4690 if (!cgrp->parent || !((val == 0) || (val == 1))) 4691 return -EINVAL; 4692 4693 parent = mem_cgroup_from_cont(cgrp->parent); 4694 4695 cgroup_lock(); 4696 /* oom-kill-disable is a flag for subhierarchy. */ 4697 if ((parent->use_hierarchy) || 4698 (memcg->use_hierarchy && !list_empty(&cgrp->children))) { 4699 cgroup_unlock(); 4700 return -EINVAL; 4701 } 4702 memcg->oom_kill_disable = val; 4703 if (!val) 4704 memcg_oom_recover(memcg); 4705 cgroup_unlock(); 4706 return 0; 4707} 4708 4709#ifdef CONFIG_NUMA 4710static const struct file_operations mem_control_numa_stat_file_operations = { 4711 .read = seq_read, 4712 .llseek = seq_lseek, 4713 .release = single_release, 4714}; 4715 4716static int mem_control_numa_stat_open(struct inode *unused, struct file *file) 4717{ 4718 struct cgroup *cont = file->f_dentry->d_parent->d_fsdata; 4719 4720 file->f_op = &mem_control_numa_stat_file_operations; 4721 return single_open(file, mem_control_numa_stat_show, cont); 4722} 4723#endif /* CONFIG_NUMA */ 4724 4725#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM 4726static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) 4727{ 4728 /* 4729 * Part of this would be better living in a separate allocation 4730 * function, leaving us with just the cgroup tree population work. 4731 * We, however, depend on state such as network's proto_list that 4732 * is only initialized after cgroup creation. I found the less 4733 * cumbersome way to deal with it to defer it all to populate time 4734 */ 4735 return mem_cgroup_sockets_init(cont, ss); 4736}; 4737 4738static void kmem_cgroup_destroy(struct cgroup_subsys *ss, 4739 struct cgroup *cont) 4740{ 4741 mem_cgroup_sockets_destroy(cont, ss); 4742} 4743#else 4744static int register_kmem_files(struct cgroup *cont, struct cgroup_subsys *ss) 4745{ 4746 return 0; 4747} 4748 4749static void kmem_cgroup_destroy(struct cgroup_subsys *ss, 4750 struct cgroup *cont) 4751{ 4752} 4753#endif 4754 4755static struct cftype mem_cgroup_files[] = { 4756 { 4757 .name = "usage_in_bytes", 4758 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), 4759 .read_u64 = mem_cgroup_read, 4760 .register_event = mem_cgroup_usage_register_event, 4761 .unregister_event = mem_cgroup_usage_unregister_event, 4762 }, 4763 { 4764 .name = "max_usage_in_bytes", 4765 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), 4766 .trigger = mem_cgroup_reset, 4767 .read_u64 = mem_cgroup_read, 4768 }, 4769 { 4770 .name = "limit_in_bytes", 4771 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), 4772 .write_string = mem_cgroup_write, 4773 .read_u64 = mem_cgroup_read, 4774 }, 4775 { 4776 .name = "soft_limit_in_bytes", 4777 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), 4778 .write_string = mem_cgroup_write, 4779 .read_u64 = mem_cgroup_read, 4780 }, 4781 { 4782 .name = "failcnt", 4783 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), 4784 .trigger = mem_cgroup_reset, 4785 .read_u64 = mem_cgroup_read, 4786 }, 4787 { 4788 .name = "stat", 4789 .read_map = mem_control_stat_show, 4790 }, 4791 { 4792 .name = "force_empty", 4793 .trigger = mem_cgroup_force_empty_write, 4794 }, 4795 { 4796 .name = "use_hierarchy", 4797 .write_u64 = mem_cgroup_hierarchy_write, 4798 .read_u64 = mem_cgroup_hierarchy_read, 4799 }, 4800 { 4801 .name = "swappiness", 4802 .read_u64 = mem_cgroup_swappiness_read, 4803 .write_u64 = mem_cgroup_swappiness_write, 4804 }, 4805 { 4806 .name = "move_charge_at_immigrate", 4807 .read_u64 = mem_cgroup_move_charge_read, 4808 .write_u64 = mem_cgroup_move_charge_write, 4809 }, 4810 { 4811 .name = "oom_control", 4812 .read_map = mem_cgroup_oom_control_read, 4813 .write_u64 = mem_cgroup_oom_control_write, 4814 .register_event = mem_cgroup_oom_register_event, 4815 .unregister_event = mem_cgroup_oom_unregister_event, 4816 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), 4817 }, 4818#ifdef CONFIG_NUMA 4819 { 4820 .name = "numa_stat", 4821 .open = mem_control_numa_stat_open, 4822 .mode = S_IRUGO, 4823 }, 4824#endif 4825}; 4826 4827#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4828static struct cftype memsw_cgroup_files[] = { 4829 { 4830 .name = "memsw.usage_in_bytes", 4831 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), 4832 .read_u64 = mem_cgroup_read, 4833 .register_event = mem_cgroup_usage_register_event, 4834 .unregister_event = mem_cgroup_usage_unregister_event, 4835 }, 4836 { 4837 .name = "memsw.max_usage_in_bytes", 4838 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), 4839 .trigger = mem_cgroup_reset, 4840 .read_u64 = mem_cgroup_read, 4841 }, 4842 { 4843 .name = "memsw.limit_in_bytes", 4844 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), 4845 .write_string = mem_cgroup_write, 4846 .read_u64 = mem_cgroup_read, 4847 }, 4848 { 4849 .name = "memsw.failcnt", 4850 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), 4851 .trigger = mem_cgroup_reset, 4852 .read_u64 = mem_cgroup_read, 4853 }, 4854}; 4855 4856static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 4857{ 4858 if (!do_swap_account) 4859 return 0; 4860 return cgroup_add_files(cont, ss, memsw_cgroup_files, 4861 ARRAY_SIZE(memsw_cgroup_files)); 4862}; 4863#else 4864static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 4865{ 4866 return 0; 4867} 4868#endif 4869 4870static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) 4871{ 4872 struct mem_cgroup_per_node *pn; 4873 struct mem_cgroup_per_zone *mz; 4874 enum lru_list l; 4875 int zone, tmp = node; 4876 /* 4877 * This routine is called against possible nodes. 4878 * But it's BUG to call kmalloc() against offline node. 4879 * 4880 * TODO: this routine can waste much memory for nodes which will 4881 * never be onlined. It's better to use memory hotplug callback 4882 * function. 4883 */ 4884 if (!node_state(node, N_NORMAL_MEMORY)) 4885 tmp = -1; 4886 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); 4887 if (!pn) 4888 return 1; 4889 4890 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 4891 mz = &pn->zoneinfo[zone]; 4892 for_each_lru(l) 4893 INIT_LIST_HEAD(&mz->lists[l]); 4894 mz->usage_in_excess = 0; 4895 mz->on_tree = false; 4896 mz->mem = memcg; 4897 } 4898 memcg->info.nodeinfo[node] = pn; 4899 return 0; 4900} 4901 4902static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node) 4903{ 4904 kfree(memcg->info.nodeinfo[node]); 4905} 4906 4907static struct mem_cgroup *mem_cgroup_alloc(void) 4908{ 4909 struct mem_cgroup *mem; 4910 int size = sizeof(struct mem_cgroup); 4911 4912 /* Can be very big if MAX_NUMNODES is very big */ 4913 if (size < PAGE_SIZE) 4914 mem = kzalloc(size, GFP_KERNEL); 4915 else 4916 mem = vzalloc(size); 4917 4918 if (!mem) 4919 return NULL; 4920 4921 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu); 4922 if (!mem->stat) 4923 goto out_free; 4924 spin_lock_init(&mem->pcp_counter_lock); 4925 return mem; 4926 4927out_free: 4928 if (size < PAGE_SIZE) 4929 kfree(mem); 4930 else 4931 vfree(mem); 4932 return NULL; 4933} 4934 4935/* 4936 * At destroying mem_cgroup, references from swap_cgroup can remain. 4937 * (scanning all at force_empty is too costly...) 4938 * 4939 * Instead of clearing all references at force_empty, we remember 4940 * the number of reference from swap_cgroup and free mem_cgroup when 4941 * it goes down to 0. 4942 * 4943 * Removal of cgroup itself succeeds regardless of refs from swap. 4944 */ 4945 4946static void __mem_cgroup_free(struct mem_cgroup *memcg) 4947{ 4948 int node; 4949 4950 mem_cgroup_remove_from_trees(memcg); 4951 free_css_id(&mem_cgroup_subsys, &memcg->css); 4952 4953 for_each_node_state(node, N_POSSIBLE) 4954 free_mem_cgroup_per_zone_info(memcg, node); 4955 4956 free_percpu(memcg->stat); 4957 if (sizeof(struct mem_cgroup) < PAGE_SIZE) 4958 kfree(memcg); 4959 else 4960 vfree(memcg); 4961} 4962 4963static void mem_cgroup_get(struct mem_cgroup *memcg) 4964{ 4965 atomic_inc(&memcg->refcnt); 4966} 4967 4968static void __mem_cgroup_put(struct mem_cgroup *memcg, int count) 4969{ 4970 if (atomic_sub_and_test(count, &memcg->refcnt)) { 4971 struct mem_cgroup *parent = parent_mem_cgroup(memcg); 4972 __mem_cgroup_free(memcg); 4973 if (parent) 4974 mem_cgroup_put(parent); 4975 } 4976} 4977 4978static void mem_cgroup_put(struct mem_cgroup *memcg) 4979{ 4980 __mem_cgroup_put(memcg, 1); 4981} 4982 4983/* 4984 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. 4985 */ 4986struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg) 4987{ 4988 if (!memcg->res.parent) 4989 return NULL; 4990 return mem_cgroup_from_res_counter(memcg->res.parent, res); 4991} 4992EXPORT_SYMBOL(parent_mem_cgroup); 4993 4994#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4995static void __init enable_swap_cgroup(void) 4996{ 4997 if (!mem_cgroup_disabled() && really_do_swap_account) 4998 do_swap_account = 1; 4999} 5000#else 5001static void __init enable_swap_cgroup(void) 5002{ 5003} 5004#endif 5005 5006static int mem_cgroup_soft_limit_tree_init(void) 5007{ 5008 struct mem_cgroup_tree_per_node *rtpn; 5009 struct mem_cgroup_tree_per_zone *rtpz; 5010 int tmp, node, zone; 5011 5012 for_each_node_state(node, N_POSSIBLE) { 5013 tmp = node; 5014 if (!node_state(node, N_NORMAL_MEMORY)) 5015 tmp = -1; 5016 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); 5017 if (!rtpn) 5018 return 1; 5019 5020 soft_limit_tree.rb_tree_per_node[node] = rtpn; 5021 5022 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 5023 rtpz = &rtpn->rb_tree_per_zone[zone]; 5024 rtpz->rb_root = RB_ROOT; 5025 spin_lock_init(&rtpz->lock); 5026 } 5027 } 5028 return 0; 5029} 5030 5031static struct cgroup_subsys_state * __ref 5032mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 5033{ 5034 struct mem_cgroup *memcg, *parent; 5035 long error = -ENOMEM; 5036 int node; 5037 5038 memcg = mem_cgroup_alloc(); 5039 if (!memcg) 5040 return ERR_PTR(error); 5041 5042 for_each_node_state(node, N_POSSIBLE) 5043 if (alloc_mem_cgroup_per_zone_info(memcg, node)) 5044 goto free_out; 5045 5046 /* root ? */ 5047 if (cont->parent == NULL) { 5048 int cpu; 5049 enable_swap_cgroup(); 5050 parent = NULL; 5051 if (mem_cgroup_soft_limit_tree_init()) 5052 goto free_out; 5053 root_mem_cgroup = memcg; 5054 for_each_possible_cpu(cpu) { 5055 struct memcg_stock_pcp *stock = 5056 &per_cpu(memcg_stock, cpu); 5057 INIT_WORK(&stock->work, drain_local_stock); 5058 } 5059 hotcpu_notifier(memcg_cpu_hotplug_callback, 0); 5060 } else { 5061 parent = mem_cgroup_from_cont(cont->parent); 5062 memcg->use_hierarchy = parent->use_hierarchy; 5063 memcg->oom_kill_disable = parent->oom_kill_disable; 5064 } 5065 5066 if (parent && parent->use_hierarchy) { 5067 res_counter_init(&memcg->res, &parent->res); 5068 res_counter_init(&memcg->memsw, &parent->memsw); 5069 /* 5070 * We increment refcnt of the parent to ensure that we can 5071 * safely access it on res_counter_charge/uncharge. 5072 * This refcnt will be decremented when freeing this 5073 * mem_cgroup(see mem_cgroup_put). 5074 */ 5075 mem_cgroup_get(parent); 5076 } else { 5077 res_counter_init(&memcg->res, NULL); 5078 res_counter_init(&memcg->memsw, NULL); 5079 } 5080 memcg->last_scanned_child = 0; 5081 memcg->last_scanned_node = MAX_NUMNODES; 5082 INIT_LIST_HEAD(&memcg->oom_notify); 5083 5084 if (parent) 5085 memcg->swappiness = mem_cgroup_swappiness(parent); 5086 atomic_set(&memcg->refcnt, 1); 5087 memcg->move_charge_at_immigrate = 0; 5088 mutex_init(&memcg->thresholds_lock); 5089 return &memcg->css; 5090free_out: 5091 __mem_cgroup_free(memcg); 5092 return ERR_PTR(error); 5093} 5094 5095static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, 5096 struct cgroup *cont) 5097{ 5098 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 5099 5100 return mem_cgroup_force_empty(memcg, false); 5101} 5102 5103static void mem_cgroup_destroy(struct cgroup_subsys *ss, 5104 struct cgroup *cont) 5105{ 5106 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 5107 5108 kmem_cgroup_destroy(ss, cont); 5109 5110 mem_cgroup_put(memcg); 5111} 5112 5113static int mem_cgroup_populate(struct cgroup_subsys *ss, 5114 struct cgroup *cont) 5115{ 5116 int ret; 5117 5118 ret = cgroup_add_files(cont, ss, mem_cgroup_files, 5119 ARRAY_SIZE(mem_cgroup_files)); 5120 5121 if (!ret) 5122 ret = register_memsw_files(cont, ss); 5123 5124 if (!ret) 5125 ret = register_kmem_files(cont, ss); 5126 5127 return ret; 5128} 5129 5130#ifdef CONFIG_MMU 5131/* Handlers for move charge at task migration. */ 5132#define PRECHARGE_COUNT_AT_ONCE 256 5133static int mem_cgroup_do_precharge(unsigned long count) 5134{ 5135 int ret = 0; 5136 int batch_count = PRECHARGE_COUNT_AT_ONCE; 5137 struct mem_cgroup *memcg = mc.to; 5138 5139 if (mem_cgroup_is_root(memcg)) { 5140 mc.precharge += count; 5141 /* we don't need css_get for root */ 5142 return ret; 5143 } 5144 /* try to charge at once */ 5145 if (count > 1) { 5146 struct res_counter *dummy; 5147 /* 5148 * "memcg" cannot be under rmdir() because we've already checked 5149 * by cgroup_lock_live_cgroup() that it is not removed and we 5150 * are still under the same cgroup_mutex. So we can postpone 5151 * css_get(). 5152 */ 5153 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy)) 5154 goto one_by_one; 5155 if (do_swap_account && res_counter_charge(&memcg->memsw, 5156 PAGE_SIZE * count, &dummy)) { 5157 res_counter_uncharge(&memcg->res, PAGE_SIZE * count); 5158 goto one_by_one; 5159 } 5160 mc.precharge += count; 5161 return ret; 5162 } 5163one_by_one: 5164 /* fall back to one by one charge */ 5165 while (count--) { 5166 if (signal_pending(current)) { 5167 ret = -EINTR; 5168 break; 5169 } 5170 if (!batch_count--) { 5171 batch_count = PRECHARGE_COUNT_AT_ONCE; 5172 cond_resched(); 5173 } 5174 ret = __mem_cgroup_try_charge(NULL, 5175 GFP_KERNEL, 1, &memcg, false); 5176 if (ret || !memcg) 5177 /* mem_cgroup_clear_mc() will do uncharge later */ 5178 return -ENOMEM; 5179 mc.precharge++; 5180 } 5181 return ret; 5182} 5183 5184/** 5185 * is_target_pte_for_mc - check a pte whether it is valid for move charge 5186 * @vma: the vma the pte to be checked belongs 5187 * @addr: the address corresponding to the pte to be checked 5188 * @ptent: the pte to be checked 5189 * @target: the pointer the target page or swap ent will be stored(can be NULL) 5190 * 5191 * Returns 5192 * 0(MC_TARGET_NONE): if the pte is not a target for move charge. 5193 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for 5194 * move charge. if @target is not NULL, the page is stored in target->page 5195 * with extra refcnt got(Callers should handle it). 5196 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a 5197 * target for charge migration. if @target is not NULL, the entry is stored 5198 * in target->ent. 5199 * 5200 * Called with pte lock held. 5201 */ 5202union mc_target { 5203 struct page *page; 5204 swp_entry_t ent; 5205}; 5206 5207enum mc_target_type { 5208 MC_TARGET_NONE, /* not used */ 5209 MC_TARGET_PAGE, 5210 MC_TARGET_SWAP, 5211}; 5212 5213static struct page *mc_handle_present_pte(struct vm_area_struct *vma, 5214 unsigned long addr, pte_t ptent) 5215{ 5216 struct page *page = vm_normal_page(vma, addr, ptent); 5217 5218 if (!page || !page_mapped(page)) 5219 return NULL; 5220 if (PageAnon(page)) { 5221 /* we don't move shared anon */ 5222 if (!move_anon() || page_mapcount(page) > 2) 5223 return NULL; 5224 } else if (!move_file()) 5225 /* we ignore mapcount for file pages */ 5226 return NULL; 5227 if (!get_page_unless_zero(page)) 5228 return NULL; 5229 5230 return page; 5231} 5232 5233static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, 5234 unsigned long addr, pte_t ptent, swp_entry_t *entry) 5235{ 5236 int usage_count; 5237 struct page *page = NULL; 5238 swp_entry_t ent = pte_to_swp_entry(ptent); 5239 5240 if (!move_anon() || non_swap_entry(ent)) 5241 return NULL; 5242 usage_count = mem_cgroup_count_swap_user(ent, &page); 5243 if (usage_count > 1) { /* we don't move shared anon */ 5244 if (page) 5245 put_page(page); 5246 return NULL; 5247 } 5248 if (do_swap_account) 5249 entry->val = ent.val; 5250 5251 return page; 5252} 5253 5254static struct page *mc_handle_file_pte(struct vm_area_struct *vma, 5255 unsigned long addr, pte_t ptent, swp_entry_t *entry) 5256{ 5257 struct page *page = NULL; 5258 struct inode *inode; 5259 struct address_space *mapping; 5260 pgoff_t pgoff; 5261 5262 if (!vma->vm_file) /* anonymous vma */ 5263 return NULL; 5264 if (!move_file()) 5265 return NULL; 5266 5267 inode = vma->vm_file->f_path.dentry->d_inode; 5268 mapping = vma->vm_file->f_mapping; 5269 if (pte_none(ptent)) 5270 pgoff = linear_page_index(vma, addr); 5271 else /* pte_file(ptent) is true */ 5272 pgoff = pte_to_pgoff(ptent); 5273 5274 /* page is moved even if it's not RSS of this task(page-faulted). */ 5275 page = find_get_page(mapping, pgoff); 5276 5277#ifdef CONFIG_SWAP 5278 /* shmem/tmpfs may report page out on swap: account for that too. */ 5279 if (radix_tree_exceptional_entry(page)) { 5280 swp_entry_t swap = radix_to_swp_entry(page); 5281 if (do_swap_account) 5282 *entry = swap; 5283 page = find_get_page(&swapper_space, swap.val); 5284 } 5285#endif 5286 return page; 5287} 5288 5289static int is_target_pte_for_mc(struct vm_area_struct *vma, 5290 unsigned long addr, pte_t ptent, union mc_target *target) 5291{ 5292 struct page *page = NULL; 5293 struct page_cgroup *pc; 5294 int ret = 0; 5295 swp_entry_t ent = { .val = 0 }; 5296 5297 if (pte_present(ptent)) 5298 page = mc_handle_present_pte(vma, addr, ptent); 5299 else if (is_swap_pte(ptent)) 5300 page = mc_handle_swap_pte(vma, addr, ptent, &ent); 5301 else if (pte_none(ptent) || pte_file(ptent)) 5302 page = mc_handle_file_pte(vma, addr, ptent, &ent); 5303 5304 if (!page && !ent.val) 5305 return 0; 5306 if (page) { 5307 pc = lookup_page_cgroup(page); 5308 /* 5309 * Do only loose check w/o page_cgroup lock. 5310 * mem_cgroup_move_account() checks the pc is valid or not under 5311 * the lock. 5312 */ 5313 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { 5314 ret = MC_TARGET_PAGE; 5315 if (target) 5316 target->page = page; 5317 } 5318 if (!ret || !target) 5319 put_page(page); 5320 } 5321 /* There is a swap entry and a page doesn't exist or isn't charged */ 5322 if (ent.val && !ret && 5323 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { 5324 ret = MC_TARGET_SWAP; 5325 if (target) 5326 target->ent = ent; 5327 } 5328 return ret; 5329} 5330 5331static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, 5332 unsigned long addr, unsigned long end, 5333 struct mm_walk *walk) 5334{ 5335 struct vm_area_struct *vma = walk->private; 5336 pte_t *pte; 5337 spinlock_t *ptl; 5338 5339 split_huge_page_pmd(walk->mm, pmd); 5340 5341 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 5342 for (; addr != end; pte++, addr += PAGE_SIZE) 5343 if (is_target_pte_for_mc(vma, addr, *pte, NULL)) 5344 mc.precharge++; /* increment precharge temporarily */ 5345 pte_unmap_unlock(pte - 1, ptl); 5346 cond_resched(); 5347 5348 return 0; 5349} 5350 5351static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) 5352{ 5353 unsigned long precharge; 5354 struct vm_area_struct *vma; 5355 5356 down_read(&mm->mmap_sem); 5357 for (vma = mm->mmap; vma; vma = vma->vm_next) { 5358 struct mm_walk mem_cgroup_count_precharge_walk = { 5359 .pmd_entry = mem_cgroup_count_precharge_pte_range, 5360 .mm = mm, 5361 .private = vma, 5362 }; 5363 if (is_vm_hugetlb_page(vma)) 5364 continue; 5365 walk_page_range(vma->vm_start, vma->vm_end, 5366 &mem_cgroup_count_precharge_walk); 5367 } 5368 up_read(&mm->mmap_sem); 5369 5370 precharge = mc.precharge; 5371 mc.precharge = 0; 5372 5373 return precharge; 5374} 5375 5376static int mem_cgroup_precharge_mc(struct mm_struct *mm) 5377{ 5378 unsigned long precharge = mem_cgroup_count_precharge(mm); 5379 5380 VM_BUG_ON(mc.moving_task); 5381 mc.moving_task = current; 5382 return mem_cgroup_do_precharge(precharge); 5383} 5384 5385/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ 5386static void __mem_cgroup_clear_mc(void) 5387{ 5388 struct mem_cgroup *from = mc.from; 5389 struct mem_cgroup *to = mc.to; 5390 5391 /* we must uncharge all the leftover precharges from mc.to */ 5392 if (mc.precharge) { 5393 __mem_cgroup_cancel_charge(mc.to, mc.precharge); 5394 mc.precharge = 0; 5395 } 5396 /* 5397 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so 5398 * we must uncharge here. 5399 */ 5400 if (mc.moved_charge) { 5401 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); 5402 mc.moved_charge = 0; 5403 } 5404 /* we must fixup refcnts and charges */ 5405 if (mc.moved_swap) { 5406 /* uncharge swap account from the old cgroup */ 5407 if (!mem_cgroup_is_root(mc.from)) 5408 res_counter_uncharge(&mc.from->memsw, 5409 PAGE_SIZE * mc.moved_swap); 5410 __mem_cgroup_put(mc.from, mc.moved_swap); 5411 5412 if (!mem_cgroup_is_root(mc.to)) { 5413 /* 5414 * we charged both to->res and to->memsw, so we should 5415 * uncharge to->res. 5416 */ 5417 res_counter_uncharge(&mc.to->res, 5418 PAGE_SIZE * mc.moved_swap); 5419 } 5420 /* we've already done mem_cgroup_get(mc.to) */ 5421 mc.moved_swap = 0; 5422 } 5423 memcg_oom_recover(from); 5424 memcg_oom_recover(to); 5425 wake_up_all(&mc.waitq); 5426} 5427 5428static void mem_cgroup_clear_mc(void) 5429{ 5430 struct mem_cgroup *from = mc.from; 5431 5432 /* 5433 * we must clear moving_task before waking up waiters at the end of 5434 * task migration. 5435 */ 5436 mc.moving_task = NULL; 5437 __mem_cgroup_clear_mc(); 5438 spin_lock(&mc.lock); 5439 mc.from = NULL; 5440 mc.to = NULL; 5441 spin_unlock(&mc.lock); 5442 mem_cgroup_end_move(from); 5443} 5444 5445static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 5446 struct cgroup *cgroup, 5447 struct cgroup_taskset *tset) 5448{ 5449 struct task_struct *p = cgroup_taskset_first(tset); 5450 int ret = 0; 5451 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup); 5452 5453 if (memcg->move_charge_at_immigrate) { 5454 struct mm_struct *mm; 5455 struct mem_cgroup *from = mem_cgroup_from_task(p); 5456 5457 VM_BUG_ON(from == memcg); 5458 5459 mm = get_task_mm(p); 5460 if (!mm) 5461 return 0; 5462 /* We move charges only when we move a owner of the mm */ 5463 if (mm->owner == p) { 5464 VM_BUG_ON(mc.from); 5465 VM_BUG_ON(mc.to); 5466 VM_BUG_ON(mc.precharge); 5467 VM_BUG_ON(mc.moved_charge); 5468 VM_BUG_ON(mc.moved_swap); 5469 mem_cgroup_start_move(from); 5470 spin_lock(&mc.lock); 5471 mc.from = from; 5472 mc.to = memcg; 5473 spin_unlock(&mc.lock); 5474 /* We set mc.moving_task later */ 5475 5476 ret = mem_cgroup_precharge_mc(mm); 5477 if (ret) 5478 mem_cgroup_clear_mc(); 5479 } 5480 mmput(mm); 5481 } 5482 return ret; 5483} 5484 5485static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 5486 struct cgroup *cgroup, 5487 struct cgroup_taskset *tset) 5488{ 5489 mem_cgroup_clear_mc(); 5490} 5491 5492static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, 5493 unsigned long addr, unsigned long end, 5494 struct mm_walk *walk) 5495{ 5496 int ret = 0; 5497 struct vm_area_struct *vma = walk->private; 5498 pte_t *pte; 5499 spinlock_t *ptl; 5500 5501 split_huge_page_pmd(walk->mm, pmd); 5502retry: 5503 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 5504 for (; addr != end; addr += PAGE_SIZE) { 5505 pte_t ptent = *(pte++); 5506 union mc_target target; 5507 int type; 5508 struct page *page; 5509 struct page_cgroup *pc; 5510 swp_entry_t ent; 5511 5512 if (!mc.precharge) 5513 break; 5514 5515 type = is_target_pte_for_mc(vma, addr, ptent, &target); 5516 switch (type) { 5517 case MC_TARGET_PAGE: 5518 page = target.page; 5519 if (isolate_lru_page(page)) 5520 goto put; 5521 pc = lookup_page_cgroup(page); 5522 if (!mem_cgroup_move_account(page, 1, pc, 5523 mc.from, mc.to, false)) { 5524 mc.precharge--; 5525 /* we uncharge from mc.from later. */ 5526 mc.moved_charge++; 5527 } 5528 putback_lru_page(page); 5529put: /* is_target_pte_for_mc() gets the page */ 5530 put_page(page); 5531 break; 5532 case MC_TARGET_SWAP: 5533 ent = target.ent; 5534 if (!mem_cgroup_move_swap_account(ent, 5535 mc.from, mc.to, false)) { 5536 mc.precharge--; 5537 /* we fixup refcnts and charges later. */ 5538 mc.moved_swap++; 5539 } 5540 break; 5541 default: 5542 break; 5543 } 5544 } 5545 pte_unmap_unlock(pte - 1, ptl); 5546 cond_resched(); 5547 5548 if (addr != end) { 5549 /* 5550 * We have consumed all precharges we got in can_attach(). 5551 * We try charge one by one, but don't do any additional 5552 * charges to mc.to if we have failed in charge once in attach() 5553 * phase. 5554 */ 5555 ret = mem_cgroup_do_precharge(1); 5556 if (!ret) 5557 goto retry; 5558 } 5559 5560 return ret; 5561} 5562 5563static void mem_cgroup_move_charge(struct mm_struct *mm) 5564{ 5565 struct vm_area_struct *vma; 5566 5567 lru_add_drain_all(); 5568retry: 5569 if (unlikely(!down_read_trylock(&mm->mmap_sem))) { 5570 /* 5571 * Someone who are holding the mmap_sem might be waiting in 5572 * waitq. So we cancel all extra charges, wake up all waiters, 5573 * and retry. Because we cancel precharges, we might not be able 5574 * to move enough charges, but moving charge is a best-effort 5575 * feature anyway, so it wouldn't be a big problem. 5576 */ 5577 __mem_cgroup_clear_mc(); 5578 cond_resched(); 5579 goto retry; 5580 } 5581 for (vma = mm->mmap; vma; vma = vma->vm_next) { 5582 int ret; 5583 struct mm_walk mem_cgroup_move_charge_walk = { 5584 .pmd_entry = mem_cgroup_move_charge_pte_range, 5585 .mm = mm, 5586 .private = vma, 5587 }; 5588 if (is_vm_hugetlb_page(vma)) 5589 continue; 5590 ret = walk_page_range(vma->vm_start, vma->vm_end, 5591 &mem_cgroup_move_charge_walk); 5592 if (ret) 5593 /* 5594 * means we have consumed all precharges and failed in 5595 * doing additional charge. Just abandon here. 5596 */ 5597 break; 5598 } 5599 up_read(&mm->mmap_sem); 5600} 5601 5602static void mem_cgroup_move_task(struct cgroup_subsys *ss, 5603 struct cgroup *cont, 5604 struct cgroup_taskset *tset) 5605{ 5606 struct task_struct *p = cgroup_taskset_first(tset); 5607 struct mm_struct *mm = get_task_mm(p); 5608 5609 if (mm) { 5610 if (mc.to) 5611 mem_cgroup_move_charge(mm); 5612 put_swap_token(mm); 5613 mmput(mm); 5614 } 5615 if (mc.to) 5616 mem_cgroup_clear_mc(); 5617} 5618#else /* !CONFIG_MMU */ 5619static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 5620 struct cgroup *cgroup, 5621 struct cgroup_taskset *tset) 5622{ 5623 return 0; 5624} 5625static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 5626 struct cgroup *cgroup, 5627 struct cgroup_taskset *tset) 5628{ 5629} 5630static void mem_cgroup_move_task(struct cgroup_subsys *ss, 5631 struct cgroup *cont, 5632 struct cgroup_taskset *tset) 5633{ 5634} 5635#endif 5636 5637struct cgroup_subsys mem_cgroup_subsys = { 5638 .name = "memory", 5639 .subsys_id = mem_cgroup_subsys_id, 5640 .create = mem_cgroup_create, 5641 .pre_destroy = mem_cgroup_pre_destroy, 5642 .destroy = mem_cgroup_destroy, 5643 .populate = mem_cgroup_populate, 5644 .can_attach = mem_cgroup_can_attach, 5645 .cancel_attach = mem_cgroup_cancel_attach, 5646 .attach = mem_cgroup_move_task, 5647 .early_init = 0, 5648 .use_id = 1, 5649}; 5650 5651#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 5652static int __init enable_swap_account(char *s) 5653{ 5654 /* consider enabled if no parameter or 1 is given */ 5655 if (!strcmp(s, "1")) 5656 really_do_swap_account = 1; 5657 else if (!strcmp(s, "0")) 5658 really_do_swap_account = 0; 5659 return 1; 5660} 5661__setup("swapaccount=", enable_swap_account); 5662 5663#endif 5664