memcontrol.c revision 14fec79680f7cc4617d6ba69324e63d4a732986c
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/mutex.h> 37#include <linux/rbtree.h> 38#include <linux/slab.h> 39#include <linux/swap.h> 40#include <linux/swapops.h> 41#include <linux/spinlock.h> 42#include <linux/eventfd.h> 43#include <linux/sort.h> 44#include <linux/fs.h> 45#include <linux/seq_file.h> 46#include <linux/vmalloc.h> 47#include <linux/mm_inline.h> 48#include <linux/page_cgroup.h> 49#include <linux/cpu.h> 50#include <linux/oom.h> 51#include "internal.h" 52 53#include <asm/uaccess.h> 54 55#include <trace/events/vmscan.h> 56 57struct cgroup_subsys mem_cgroup_subsys __read_mostly; 58#define MEM_CGROUP_RECLAIM_RETRIES 5 59struct mem_cgroup *root_mem_cgroup __read_mostly; 60 61#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 62/* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */ 63int do_swap_account __read_mostly; 64static int really_do_swap_account __initdata = 1; /* for remember boot option*/ 65#else 66#define do_swap_account (0) 67#endif 68 69/* 70 * Per memcg event counter is incremented at every pagein/pageout. This counter 71 * is used for trigger some periodic events. This is straightforward and better 72 * than using jiffies etc. to handle periodic memcg event. 73 * 74 * These values will be used as !((event) & ((1 <<(thresh)) - 1)) 75 */ 76#define THRESHOLDS_EVENTS_THRESH (7) /* once in 128 */ 77#define SOFTLIMIT_EVENTS_THRESH (10) /* once in 1024 */ 78 79/* 80 * Statistics for memory cgroup. 81 */ 82enum mem_cgroup_stat_index { 83 /* 84 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. 85 */ 86 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ 87 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ 88 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ 89 MEM_CGROUP_STAT_PGPGIN_COUNT, /* # of pages paged in */ 90 MEM_CGROUP_STAT_PGPGOUT_COUNT, /* # of pages paged out */ 91 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ 92 MEM_CGROUP_EVENTS, /* incremented at every pagein/pageout */ 93 94 MEM_CGROUP_STAT_NSTATS, 95}; 96 97struct mem_cgroup_stat_cpu { 98 s64 count[MEM_CGROUP_STAT_NSTATS]; 99}; 100 101/* 102 * per-zone information in memory controller. 103 */ 104struct mem_cgroup_per_zone { 105 /* 106 * spin_lock to protect the per cgroup LRU 107 */ 108 struct list_head lists[NR_LRU_LISTS]; 109 unsigned long count[NR_LRU_LISTS]; 110 111 struct zone_reclaim_stat reclaim_stat; 112 struct rb_node tree_node; /* RB tree node */ 113 unsigned long long usage_in_excess;/* Set to the value by which */ 114 /* the soft limit is exceeded*/ 115 bool on_tree; 116 struct mem_cgroup *mem; /* Back pointer, we cannot */ 117 /* use container_of */ 118}; 119/* Macro for accessing counter */ 120#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) 121 122struct mem_cgroup_per_node { 123 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; 124}; 125 126struct mem_cgroup_lru_info { 127 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; 128}; 129 130/* 131 * Cgroups above their limits are maintained in a RB-Tree, independent of 132 * their hierarchy representation 133 */ 134 135struct mem_cgroup_tree_per_zone { 136 struct rb_root rb_root; 137 spinlock_t lock; 138}; 139 140struct mem_cgroup_tree_per_node { 141 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; 142}; 143 144struct mem_cgroup_tree { 145 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; 146}; 147 148static struct mem_cgroup_tree soft_limit_tree __read_mostly; 149 150struct mem_cgroup_threshold { 151 struct eventfd_ctx *eventfd; 152 u64 threshold; 153}; 154 155/* For threshold */ 156struct mem_cgroup_threshold_ary { 157 /* An array index points to threshold just below usage. */ 158 int current_threshold; 159 /* Size of entries[] */ 160 unsigned int size; 161 /* Array of thresholds */ 162 struct mem_cgroup_threshold entries[0]; 163}; 164 165struct mem_cgroup_thresholds { 166 /* Primary thresholds array */ 167 struct mem_cgroup_threshold_ary *primary; 168 /* 169 * Spare threshold array. 170 * This is needed to make mem_cgroup_unregister_event() "never fail". 171 * It must be able to store at least primary->size - 1 entries. 172 */ 173 struct mem_cgroup_threshold_ary *spare; 174}; 175 176/* for OOM */ 177struct mem_cgroup_eventfd_list { 178 struct list_head list; 179 struct eventfd_ctx *eventfd; 180}; 181 182static void mem_cgroup_threshold(struct mem_cgroup *mem); 183static void mem_cgroup_oom_notify(struct mem_cgroup *mem); 184 185/* 186 * The memory controller data structure. The memory controller controls both 187 * page cache and RSS per cgroup. We would eventually like to provide 188 * statistics based on the statistics developed by Rik Van Riel for clock-pro, 189 * to help the administrator determine what knobs to tune. 190 * 191 * TODO: Add a water mark for the memory controller. Reclaim will begin when 192 * we hit the water mark. May be even add a low water mark, such that 193 * no reclaim occurs from a cgroup at it's low water mark, this is 194 * a feature that will be implemented much later in the future. 195 */ 196struct mem_cgroup { 197 struct cgroup_subsys_state css; 198 /* 199 * the counter to account for memory usage 200 */ 201 struct res_counter res; 202 /* 203 * the counter to account for mem+swap usage. 204 */ 205 struct res_counter memsw; 206 /* 207 * Per cgroup active and inactive list, similar to the 208 * per zone LRU lists. 209 */ 210 struct mem_cgroup_lru_info info; 211 212 /* 213 protect against reclaim related member. 214 */ 215 spinlock_t reclaim_param_lock; 216 217 /* 218 * While reclaiming in a hierarchy, we cache the last child we 219 * reclaimed from. 220 */ 221 int last_scanned_child; 222 /* 223 * Should the accounting and control be hierarchical, per subtree? 224 */ 225 bool use_hierarchy; 226 atomic_t oom_lock; 227 atomic_t refcnt; 228 229 unsigned int swappiness; 230 /* OOM-Killer disable */ 231 int oom_kill_disable; 232 233 /* set when res.limit == memsw.limit */ 234 bool memsw_is_minimum; 235 236 /* protect arrays of thresholds */ 237 struct mutex thresholds_lock; 238 239 /* thresholds for memory usage. RCU-protected */ 240 struct mem_cgroup_thresholds thresholds; 241 242 /* thresholds for mem+swap usage. RCU-protected */ 243 struct mem_cgroup_thresholds memsw_thresholds; 244 245 /* For oom notifier event fd */ 246 struct list_head oom_notify; 247 248 /* 249 * Should we move charges of a task when a task is moved into this 250 * mem_cgroup ? And what type of charges should we move ? 251 */ 252 unsigned long move_charge_at_immigrate; 253 /* 254 * percpu counter. 255 */ 256 struct mem_cgroup_stat_cpu *stat; 257}; 258 259/* Stuffs for move charges at task migration. */ 260/* 261 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a 262 * left-shifted bitmap of these types. 263 */ 264enum move_type { 265 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ 266 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ 267 NR_MOVE_TYPE, 268}; 269 270/* "mc" and its members are protected by cgroup_mutex */ 271static struct move_charge_struct { 272 spinlock_t lock; /* for from, to, moving_task */ 273 struct mem_cgroup *from; 274 struct mem_cgroup *to; 275 unsigned long precharge; 276 unsigned long moved_charge; 277 unsigned long moved_swap; 278 struct task_struct *moving_task; /* a task moving charges */ 279 wait_queue_head_t waitq; /* a waitq for other context */ 280} mc = { 281 .lock = __SPIN_LOCK_UNLOCKED(mc.lock), 282 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), 283}; 284 285static bool move_anon(void) 286{ 287 return test_bit(MOVE_CHARGE_TYPE_ANON, 288 &mc.to->move_charge_at_immigrate); 289} 290 291static bool move_file(void) 292{ 293 return test_bit(MOVE_CHARGE_TYPE_FILE, 294 &mc.to->move_charge_at_immigrate); 295} 296 297/* 298 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft 299 * limit reclaim to prevent infinite loops, if they ever occur. 300 */ 301#define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) 302#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) 303 304enum charge_type { 305 MEM_CGROUP_CHARGE_TYPE_CACHE = 0, 306 MEM_CGROUP_CHARGE_TYPE_MAPPED, 307 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ 308 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ 309 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ 310 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ 311 NR_CHARGE_TYPE, 312}; 313 314/* only for here (for easy reading.) */ 315#define PCGF_CACHE (1UL << PCG_CACHE) 316#define PCGF_USED (1UL << PCG_USED) 317#define PCGF_LOCK (1UL << PCG_LOCK) 318/* Not used, but added here for completeness */ 319#define PCGF_ACCT (1UL << PCG_ACCT) 320 321/* for encoding cft->private value on file */ 322#define _MEM (0) 323#define _MEMSWAP (1) 324#define _OOM_TYPE (2) 325#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) 326#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) 327#define MEMFILE_ATTR(val) ((val) & 0xffff) 328/* Used for OOM nofiier */ 329#define OOM_CONTROL (0) 330 331/* 332 * Reclaim flags for mem_cgroup_hierarchical_reclaim 333 */ 334#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 335#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) 336#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 337#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) 338#define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2 339#define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT) 340 341static void mem_cgroup_get(struct mem_cgroup *mem); 342static void mem_cgroup_put(struct mem_cgroup *mem); 343static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); 344static void drain_all_stock_async(void); 345 346static struct mem_cgroup_per_zone * 347mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) 348{ 349 return &mem->info.nodeinfo[nid]->zoneinfo[zid]; 350} 351 352struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem) 353{ 354 return &mem->css; 355} 356 357static struct mem_cgroup_per_zone * 358page_cgroup_zoneinfo(struct page_cgroup *pc) 359{ 360 struct mem_cgroup *mem = pc->mem_cgroup; 361 int nid = page_cgroup_nid(pc); 362 int zid = page_cgroup_zid(pc); 363 364 if (!mem) 365 return NULL; 366 367 return mem_cgroup_zoneinfo(mem, nid, zid); 368} 369 370static struct mem_cgroup_tree_per_zone * 371soft_limit_tree_node_zone(int nid, int zid) 372{ 373 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 374} 375 376static struct mem_cgroup_tree_per_zone * 377soft_limit_tree_from_page(struct page *page) 378{ 379 int nid = page_to_nid(page); 380 int zid = page_zonenum(page); 381 382 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 383} 384 385static void 386__mem_cgroup_insert_exceeded(struct mem_cgroup *mem, 387 struct mem_cgroup_per_zone *mz, 388 struct mem_cgroup_tree_per_zone *mctz, 389 unsigned long long new_usage_in_excess) 390{ 391 struct rb_node **p = &mctz->rb_root.rb_node; 392 struct rb_node *parent = NULL; 393 struct mem_cgroup_per_zone *mz_node; 394 395 if (mz->on_tree) 396 return; 397 398 mz->usage_in_excess = new_usage_in_excess; 399 if (!mz->usage_in_excess) 400 return; 401 while (*p) { 402 parent = *p; 403 mz_node = rb_entry(parent, struct mem_cgroup_per_zone, 404 tree_node); 405 if (mz->usage_in_excess < mz_node->usage_in_excess) 406 p = &(*p)->rb_left; 407 /* 408 * We can't avoid mem cgroups that are over their soft 409 * limit by the same amount 410 */ 411 else if (mz->usage_in_excess >= mz_node->usage_in_excess) 412 p = &(*p)->rb_right; 413 } 414 rb_link_node(&mz->tree_node, parent, p); 415 rb_insert_color(&mz->tree_node, &mctz->rb_root); 416 mz->on_tree = true; 417} 418 419static void 420__mem_cgroup_remove_exceeded(struct mem_cgroup *mem, 421 struct mem_cgroup_per_zone *mz, 422 struct mem_cgroup_tree_per_zone *mctz) 423{ 424 if (!mz->on_tree) 425 return; 426 rb_erase(&mz->tree_node, &mctz->rb_root); 427 mz->on_tree = false; 428} 429 430static void 431mem_cgroup_remove_exceeded(struct mem_cgroup *mem, 432 struct mem_cgroup_per_zone *mz, 433 struct mem_cgroup_tree_per_zone *mctz) 434{ 435 spin_lock(&mctz->lock); 436 __mem_cgroup_remove_exceeded(mem, mz, mctz); 437 spin_unlock(&mctz->lock); 438} 439 440 441static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) 442{ 443 unsigned long long excess; 444 struct mem_cgroup_per_zone *mz; 445 struct mem_cgroup_tree_per_zone *mctz; 446 int nid = page_to_nid(page); 447 int zid = page_zonenum(page); 448 mctz = soft_limit_tree_from_page(page); 449 450 /* 451 * Necessary to update all ancestors when hierarchy is used. 452 * because their event counter is not touched. 453 */ 454 for (; mem; mem = parent_mem_cgroup(mem)) { 455 mz = mem_cgroup_zoneinfo(mem, nid, zid); 456 excess = res_counter_soft_limit_excess(&mem->res); 457 /* 458 * We have to update the tree if mz is on RB-tree or 459 * mem is over its softlimit. 460 */ 461 if (excess || mz->on_tree) { 462 spin_lock(&mctz->lock); 463 /* if on-tree, remove it */ 464 if (mz->on_tree) 465 __mem_cgroup_remove_exceeded(mem, mz, mctz); 466 /* 467 * Insert again. mz->usage_in_excess will be updated. 468 * If excess is 0, no tree ops. 469 */ 470 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess); 471 spin_unlock(&mctz->lock); 472 } 473 } 474} 475 476static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem) 477{ 478 int node, zone; 479 struct mem_cgroup_per_zone *mz; 480 struct mem_cgroup_tree_per_zone *mctz; 481 482 for_each_node_state(node, N_POSSIBLE) { 483 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 484 mz = mem_cgroup_zoneinfo(mem, node, zone); 485 mctz = soft_limit_tree_node_zone(node, zone); 486 mem_cgroup_remove_exceeded(mem, mz, mctz); 487 } 488 } 489} 490 491static inline unsigned long mem_cgroup_get_excess(struct mem_cgroup *mem) 492{ 493 return res_counter_soft_limit_excess(&mem->res) >> PAGE_SHIFT; 494} 495 496static struct mem_cgroup_per_zone * 497__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 498{ 499 struct rb_node *rightmost = NULL; 500 struct mem_cgroup_per_zone *mz; 501 502retry: 503 mz = NULL; 504 rightmost = rb_last(&mctz->rb_root); 505 if (!rightmost) 506 goto done; /* Nothing to reclaim from */ 507 508 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); 509 /* 510 * Remove the node now but someone else can add it back, 511 * we will to add it back at the end of reclaim to its correct 512 * position in the tree. 513 */ 514 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 515 if (!res_counter_soft_limit_excess(&mz->mem->res) || 516 !css_tryget(&mz->mem->css)) 517 goto retry; 518done: 519 return mz; 520} 521 522static struct mem_cgroup_per_zone * 523mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 524{ 525 struct mem_cgroup_per_zone *mz; 526 527 spin_lock(&mctz->lock); 528 mz = __mem_cgroup_largest_soft_limit_node(mctz); 529 spin_unlock(&mctz->lock); 530 return mz; 531} 532 533static s64 mem_cgroup_read_stat(struct mem_cgroup *mem, 534 enum mem_cgroup_stat_index idx) 535{ 536 int cpu; 537 s64 val = 0; 538 539 for_each_possible_cpu(cpu) 540 val += per_cpu(mem->stat->count[idx], cpu); 541 return val; 542} 543 544static s64 mem_cgroup_local_usage(struct mem_cgroup *mem) 545{ 546 s64 ret; 547 548 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); 549 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); 550 return ret; 551} 552 553static void mem_cgroup_swap_statistics(struct mem_cgroup *mem, 554 bool charge) 555{ 556 int val = (charge) ? 1 : -1; 557 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); 558} 559 560static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, 561 struct page_cgroup *pc, 562 bool charge) 563{ 564 int val = (charge) ? 1 : -1; 565 566 preempt_disable(); 567 568 if (PageCgroupCache(pc)) 569 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], val); 570 else 571 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], val); 572 573 if (charge) 574 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGIN_COUNT]); 575 else 576 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_PGPGOUT_COUNT]); 577 __this_cpu_inc(mem->stat->count[MEM_CGROUP_EVENTS]); 578 579 preempt_enable(); 580} 581 582static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, 583 enum lru_list idx) 584{ 585 int nid, zid; 586 struct mem_cgroup_per_zone *mz; 587 u64 total = 0; 588 589 for_each_online_node(nid) 590 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 591 mz = mem_cgroup_zoneinfo(mem, nid, zid); 592 total += MEM_CGROUP_ZSTAT(mz, idx); 593 } 594 return total; 595} 596 597static bool __memcg_event_check(struct mem_cgroup *mem, int event_mask_shift) 598{ 599 s64 val; 600 601 val = this_cpu_read(mem->stat->count[MEM_CGROUP_EVENTS]); 602 603 return !(val & ((1 << event_mask_shift) - 1)); 604} 605 606/* 607 * Check events in order. 608 * 609 */ 610static void memcg_check_events(struct mem_cgroup *mem, struct page *page) 611{ 612 /* threshold event is triggered in finer grain than soft limit */ 613 if (unlikely(__memcg_event_check(mem, THRESHOLDS_EVENTS_THRESH))) { 614 mem_cgroup_threshold(mem); 615 if (unlikely(__memcg_event_check(mem, SOFTLIMIT_EVENTS_THRESH))) 616 mem_cgroup_update_tree(mem, page); 617 } 618} 619 620static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) 621{ 622 return container_of(cgroup_subsys_state(cont, 623 mem_cgroup_subsys_id), struct mem_cgroup, 624 css); 625} 626 627struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 628{ 629 /* 630 * mm_update_next_owner() may clear mm->owner to NULL 631 * if it races with swapoff, page migration, etc. 632 * So this can be called with p == NULL. 633 */ 634 if (unlikely(!p)) 635 return NULL; 636 637 return container_of(task_subsys_state(p, mem_cgroup_subsys_id), 638 struct mem_cgroup, css); 639} 640 641static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 642{ 643 struct mem_cgroup *mem = NULL; 644 645 if (!mm) 646 return NULL; 647 /* 648 * Because we have no locks, mm->owner's may be being moved to other 649 * cgroup. We use css_tryget() here even if this looks 650 * pessimistic (rather than adding locks here). 651 */ 652 rcu_read_lock(); 653 do { 654 mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); 655 if (unlikely(!mem)) 656 break; 657 } while (!css_tryget(&mem->css)); 658 rcu_read_unlock(); 659 return mem; 660} 661 662/* 663 * Call callback function against all cgroup under hierarchy tree. 664 */ 665static int mem_cgroup_walk_tree(struct mem_cgroup *root, void *data, 666 int (*func)(struct mem_cgroup *, void *)) 667{ 668 int found, ret, nextid; 669 struct cgroup_subsys_state *css; 670 struct mem_cgroup *mem; 671 672 if (!root->use_hierarchy) 673 return (*func)(root, data); 674 675 nextid = 1; 676 do { 677 ret = 0; 678 mem = NULL; 679 680 rcu_read_lock(); 681 css = css_get_next(&mem_cgroup_subsys, nextid, &root->css, 682 &found); 683 if (css && css_tryget(css)) 684 mem = container_of(css, struct mem_cgroup, css); 685 rcu_read_unlock(); 686 687 if (mem) { 688 ret = (*func)(mem, data); 689 css_put(&mem->css); 690 } 691 nextid = found + 1; 692 } while (!ret && css); 693 694 return ret; 695} 696 697static inline bool mem_cgroup_is_root(struct mem_cgroup *mem) 698{ 699 return (mem == root_mem_cgroup); 700} 701 702/* 703 * Following LRU functions are allowed to be used without PCG_LOCK. 704 * Operations are called by routine of global LRU independently from memcg. 705 * What we have to take care of here is validness of pc->mem_cgroup. 706 * 707 * Changes to pc->mem_cgroup happens when 708 * 1. charge 709 * 2. moving account 710 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. 711 * It is added to LRU before charge. 712 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. 713 * When moving account, the page is not on LRU. It's isolated. 714 */ 715 716void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) 717{ 718 struct page_cgroup *pc; 719 struct mem_cgroup_per_zone *mz; 720 721 if (mem_cgroup_disabled()) 722 return; 723 pc = lookup_page_cgroup(page); 724 /* can happen while we handle swapcache. */ 725 if (!TestClearPageCgroupAcctLRU(pc)) 726 return; 727 VM_BUG_ON(!pc->mem_cgroup); 728 /* 729 * We don't check PCG_USED bit. It's cleared when the "page" is finally 730 * removed from global LRU. 731 */ 732 mz = page_cgroup_zoneinfo(pc); 733 MEM_CGROUP_ZSTAT(mz, lru) -= 1; 734 if (mem_cgroup_is_root(pc->mem_cgroup)) 735 return; 736 VM_BUG_ON(list_empty(&pc->lru)); 737 list_del_init(&pc->lru); 738 return; 739} 740 741void mem_cgroup_del_lru(struct page *page) 742{ 743 mem_cgroup_del_lru_list(page, page_lru(page)); 744} 745 746void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) 747{ 748 struct mem_cgroup_per_zone *mz; 749 struct page_cgroup *pc; 750 751 if (mem_cgroup_disabled()) 752 return; 753 754 pc = lookup_page_cgroup(page); 755 /* 756 * Used bit is set without atomic ops but after smp_wmb(). 757 * For making pc->mem_cgroup visible, insert smp_rmb() here. 758 */ 759 smp_rmb(); 760 /* unused or root page is not rotated. */ 761 if (!PageCgroupUsed(pc) || mem_cgroup_is_root(pc->mem_cgroup)) 762 return; 763 mz = page_cgroup_zoneinfo(pc); 764 list_move(&pc->lru, &mz->lists[lru]); 765} 766 767void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) 768{ 769 struct page_cgroup *pc; 770 struct mem_cgroup_per_zone *mz; 771 772 if (mem_cgroup_disabled()) 773 return; 774 pc = lookup_page_cgroup(page); 775 VM_BUG_ON(PageCgroupAcctLRU(pc)); 776 /* 777 * Used bit is set without atomic ops but after smp_wmb(). 778 * For making pc->mem_cgroup visible, insert smp_rmb() here. 779 */ 780 smp_rmb(); 781 if (!PageCgroupUsed(pc)) 782 return; 783 784 mz = page_cgroup_zoneinfo(pc); 785 MEM_CGROUP_ZSTAT(mz, lru) += 1; 786 SetPageCgroupAcctLRU(pc); 787 if (mem_cgroup_is_root(pc->mem_cgroup)) 788 return; 789 list_add(&pc->lru, &mz->lists[lru]); 790} 791 792/* 793 * At handling SwapCache, pc->mem_cgroup may be changed while it's linked to 794 * lru because the page may.be reused after it's fully uncharged (because of 795 * SwapCache behavior).To handle that, unlink page_cgroup from LRU when charge 796 * it again. This function is only used to charge SwapCache. It's done under 797 * lock_page and expected that zone->lru_lock is never held. 798 */ 799static void mem_cgroup_lru_del_before_commit_swapcache(struct page *page) 800{ 801 unsigned long flags; 802 struct zone *zone = page_zone(page); 803 struct page_cgroup *pc = lookup_page_cgroup(page); 804 805 spin_lock_irqsave(&zone->lru_lock, flags); 806 /* 807 * Forget old LRU when this page_cgroup is *not* used. This Used bit 808 * is guarded by lock_page() because the page is SwapCache. 809 */ 810 if (!PageCgroupUsed(pc)) 811 mem_cgroup_del_lru_list(page, page_lru(page)); 812 spin_unlock_irqrestore(&zone->lru_lock, flags); 813} 814 815static void mem_cgroup_lru_add_after_commit_swapcache(struct page *page) 816{ 817 unsigned long flags; 818 struct zone *zone = page_zone(page); 819 struct page_cgroup *pc = lookup_page_cgroup(page); 820 821 spin_lock_irqsave(&zone->lru_lock, flags); 822 /* link when the page is linked to LRU but page_cgroup isn't */ 823 if (PageLRU(page) && !PageCgroupAcctLRU(pc)) 824 mem_cgroup_add_lru_list(page, page_lru(page)); 825 spin_unlock_irqrestore(&zone->lru_lock, flags); 826} 827 828 829void mem_cgroup_move_lists(struct page *page, 830 enum lru_list from, enum lru_list to) 831{ 832 if (mem_cgroup_disabled()) 833 return; 834 mem_cgroup_del_lru_list(page, from); 835 mem_cgroup_add_lru_list(page, to); 836} 837 838int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) 839{ 840 int ret; 841 struct mem_cgroup *curr = NULL; 842 struct task_struct *p; 843 844 p = find_lock_task_mm(task); 845 if (!p) 846 return 0; 847 curr = try_get_mem_cgroup_from_mm(p->mm); 848 task_unlock(p); 849 if (!curr) 850 return 0; 851 /* 852 * We should check use_hierarchy of "mem" not "curr". Because checking 853 * use_hierarchy of "curr" here make this function true if hierarchy is 854 * enabled in "curr" and "curr" is a child of "mem" in *cgroup* 855 * hierarchy(even if use_hierarchy is disabled in "mem"). 856 */ 857 if (mem->use_hierarchy) 858 ret = css_is_ancestor(&curr->css, &mem->css); 859 else 860 ret = (curr == mem); 861 css_put(&curr->css); 862 return ret; 863} 864 865static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) 866{ 867 unsigned long active; 868 unsigned long inactive; 869 unsigned long gb; 870 unsigned long inactive_ratio; 871 872 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); 873 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); 874 875 gb = (inactive + active) >> (30 - PAGE_SHIFT); 876 if (gb) 877 inactive_ratio = int_sqrt(10 * gb); 878 else 879 inactive_ratio = 1; 880 881 if (present_pages) { 882 present_pages[0] = inactive; 883 present_pages[1] = active; 884 } 885 886 return inactive_ratio; 887} 888 889int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) 890{ 891 unsigned long active; 892 unsigned long inactive; 893 unsigned long present_pages[2]; 894 unsigned long inactive_ratio; 895 896 inactive_ratio = calc_inactive_ratio(memcg, present_pages); 897 898 inactive = present_pages[0]; 899 active = present_pages[1]; 900 901 if (inactive * inactive_ratio < active) 902 return 1; 903 904 return 0; 905} 906 907int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg) 908{ 909 unsigned long active; 910 unsigned long inactive; 911 912 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE); 913 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE); 914 915 return (active > inactive); 916} 917 918unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, 919 struct zone *zone, 920 enum lru_list lru) 921{ 922 int nid = zone->zone_pgdat->node_id; 923 int zid = zone_idx(zone); 924 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 925 926 return MEM_CGROUP_ZSTAT(mz, lru); 927} 928 929struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, 930 struct zone *zone) 931{ 932 int nid = zone->zone_pgdat->node_id; 933 int zid = zone_idx(zone); 934 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 935 936 return &mz->reclaim_stat; 937} 938 939struct zone_reclaim_stat * 940mem_cgroup_get_reclaim_stat_from_page(struct page *page) 941{ 942 struct page_cgroup *pc; 943 struct mem_cgroup_per_zone *mz; 944 945 if (mem_cgroup_disabled()) 946 return NULL; 947 948 pc = lookup_page_cgroup(page); 949 /* 950 * Used bit is set without atomic ops but after smp_wmb(). 951 * For making pc->mem_cgroup visible, insert smp_rmb() here. 952 */ 953 smp_rmb(); 954 if (!PageCgroupUsed(pc)) 955 return NULL; 956 957 mz = page_cgroup_zoneinfo(pc); 958 if (!mz) 959 return NULL; 960 961 return &mz->reclaim_stat; 962} 963 964unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 965 struct list_head *dst, 966 unsigned long *scanned, int order, 967 int mode, struct zone *z, 968 struct mem_cgroup *mem_cont, 969 int active, int file) 970{ 971 unsigned long nr_taken = 0; 972 struct page *page; 973 unsigned long scan; 974 LIST_HEAD(pc_list); 975 struct list_head *src; 976 struct page_cgroup *pc, *tmp; 977 int nid = z->zone_pgdat->node_id; 978 int zid = zone_idx(z); 979 struct mem_cgroup_per_zone *mz; 980 int lru = LRU_FILE * file + active; 981 int ret; 982 983 BUG_ON(!mem_cont); 984 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 985 src = &mz->lists[lru]; 986 987 scan = 0; 988 list_for_each_entry_safe_reverse(pc, tmp, src, lru) { 989 if (scan >= nr_to_scan) 990 break; 991 992 page = pc->page; 993 if (unlikely(!PageCgroupUsed(pc))) 994 continue; 995 if (unlikely(!PageLRU(page))) 996 continue; 997 998 scan++; 999 ret = __isolate_lru_page(page, mode, file); 1000 switch (ret) { 1001 case 0: 1002 list_move(&page->lru, dst); 1003 mem_cgroup_del_lru(page); 1004 nr_taken++; 1005 break; 1006 case -EBUSY: 1007 /* we don't affect global LRU but rotate in our LRU */ 1008 mem_cgroup_rotate_lru_list(page, page_lru(page)); 1009 break; 1010 default: 1011 break; 1012 } 1013 } 1014 1015 *scanned = scan; 1016 1017 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken, 1018 0, 0, 0, mode); 1019 1020 return nr_taken; 1021} 1022 1023#define mem_cgroup_from_res_counter(counter, member) \ 1024 container_of(counter, struct mem_cgroup, member) 1025 1026static bool mem_cgroup_check_under_limit(struct mem_cgroup *mem) 1027{ 1028 if (do_swap_account) { 1029 if (res_counter_check_under_limit(&mem->res) && 1030 res_counter_check_under_limit(&mem->memsw)) 1031 return true; 1032 } else 1033 if (res_counter_check_under_limit(&mem->res)) 1034 return true; 1035 return false; 1036} 1037 1038static unsigned int get_swappiness(struct mem_cgroup *memcg) 1039{ 1040 struct cgroup *cgrp = memcg->css.cgroup; 1041 unsigned int swappiness; 1042 1043 /* root ? */ 1044 if (cgrp->parent == NULL) 1045 return vm_swappiness; 1046 1047 spin_lock(&memcg->reclaim_param_lock); 1048 swappiness = memcg->swappiness; 1049 spin_unlock(&memcg->reclaim_param_lock); 1050 1051 return swappiness; 1052} 1053 1054/* A routine for testing mem is not under move_account */ 1055 1056static bool mem_cgroup_under_move(struct mem_cgroup *mem) 1057{ 1058 struct mem_cgroup *from; 1059 struct mem_cgroup *to; 1060 bool ret = false; 1061 /* 1062 * Unlike task_move routines, we access mc.to, mc.from not under 1063 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. 1064 */ 1065 spin_lock(&mc.lock); 1066 from = mc.from; 1067 to = mc.to; 1068 if (!from) 1069 goto unlock; 1070 if (from == mem || to == mem 1071 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css)) 1072 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css))) 1073 ret = true; 1074unlock: 1075 spin_unlock(&mc.lock); 1076 return ret; 1077} 1078 1079static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem) 1080{ 1081 if (mc.moving_task && current != mc.moving_task) { 1082 if (mem_cgroup_under_move(mem)) { 1083 DEFINE_WAIT(wait); 1084 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); 1085 /* moving charge context might have finished. */ 1086 if (mc.moving_task) 1087 schedule(); 1088 finish_wait(&mc.waitq, &wait); 1089 return true; 1090 } 1091 } 1092 return false; 1093} 1094 1095static int mem_cgroup_count_children_cb(struct mem_cgroup *mem, void *data) 1096{ 1097 int *val = data; 1098 (*val)++; 1099 return 0; 1100} 1101 1102/** 1103 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. 1104 * @memcg: The memory cgroup that went over limit 1105 * @p: Task that is going to be killed 1106 * 1107 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is 1108 * enabled 1109 */ 1110void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 1111{ 1112 struct cgroup *task_cgrp; 1113 struct cgroup *mem_cgrp; 1114 /* 1115 * Need a buffer in BSS, can't rely on allocations. The code relies 1116 * on the assumption that OOM is serialized for memory controller. 1117 * If this assumption is broken, revisit this code. 1118 */ 1119 static char memcg_name[PATH_MAX]; 1120 int ret; 1121 1122 if (!memcg || !p) 1123 return; 1124 1125 1126 rcu_read_lock(); 1127 1128 mem_cgrp = memcg->css.cgroup; 1129 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); 1130 1131 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); 1132 if (ret < 0) { 1133 /* 1134 * Unfortunately, we are unable to convert to a useful name 1135 * But we'll still print out the usage information 1136 */ 1137 rcu_read_unlock(); 1138 goto done; 1139 } 1140 rcu_read_unlock(); 1141 1142 printk(KERN_INFO "Task in %s killed", memcg_name); 1143 1144 rcu_read_lock(); 1145 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); 1146 if (ret < 0) { 1147 rcu_read_unlock(); 1148 goto done; 1149 } 1150 rcu_read_unlock(); 1151 1152 /* 1153 * Continues from above, so we don't need an KERN_ level 1154 */ 1155 printk(KERN_CONT " as a result of limit of %s\n", memcg_name); 1156done: 1157 1158 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", 1159 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, 1160 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, 1161 res_counter_read_u64(&memcg->res, RES_FAILCNT)); 1162 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " 1163 "failcnt %llu\n", 1164 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, 1165 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, 1166 res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); 1167} 1168 1169/* 1170 * This function returns the number of memcg under hierarchy tree. Returns 1171 * 1(self count) if no children. 1172 */ 1173static int mem_cgroup_count_children(struct mem_cgroup *mem) 1174{ 1175 int num = 0; 1176 mem_cgroup_walk_tree(mem, &num, mem_cgroup_count_children_cb); 1177 return num; 1178} 1179 1180/* 1181 * Return the memory (and swap, if configured) limit for a memcg. 1182 */ 1183u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) 1184{ 1185 u64 limit; 1186 u64 memsw; 1187 1188 limit = res_counter_read_u64(&memcg->res, RES_LIMIT) + 1189 total_swap_pages; 1190 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 1191 /* 1192 * If memsw is finite and limits the amount of swap space available 1193 * to this memcg, return that limit. 1194 */ 1195 return min(limit, memsw); 1196} 1197 1198/* 1199 * Visit the first child (need not be the first child as per the ordering 1200 * of the cgroup list, since we track last_scanned_child) of @mem and use 1201 * that to reclaim free pages from. 1202 */ 1203static struct mem_cgroup * 1204mem_cgroup_select_victim(struct mem_cgroup *root_mem) 1205{ 1206 struct mem_cgroup *ret = NULL; 1207 struct cgroup_subsys_state *css; 1208 int nextid, found; 1209 1210 if (!root_mem->use_hierarchy) { 1211 css_get(&root_mem->css); 1212 ret = root_mem; 1213 } 1214 1215 while (!ret) { 1216 rcu_read_lock(); 1217 nextid = root_mem->last_scanned_child + 1; 1218 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, 1219 &found); 1220 if (css && css_tryget(css)) 1221 ret = container_of(css, struct mem_cgroup, css); 1222 1223 rcu_read_unlock(); 1224 /* Updates scanning parameter */ 1225 spin_lock(&root_mem->reclaim_param_lock); 1226 if (!css) { 1227 /* this means start scan from ID:1 */ 1228 root_mem->last_scanned_child = 0; 1229 } else 1230 root_mem->last_scanned_child = found; 1231 spin_unlock(&root_mem->reclaim_param_lock); 1232 } 1233 1234 return ret; 1235} 1236 1237/* 1238 * Scan the hierarchy if needed to reclaim memory. We remember the last child 1239 * we reclaimed from, so that we don't end up penalizing one child extensively 1240 * based on its position in the children list. 1241 * 1242 * root_mem is the original ancestor that we've been reclaim from. 1243 * 1244 * We give up and return to the caller when we visit root_mem twice. 1245 * (other groups can be removed while we're walking....) 1246 * 1247 * If shrink==true, for avoiding to free too much, this returns immedieately. 1248 */ 1249static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 1250 struct zone *zone, 1251 gfp_t gfp_mask, 1252 unsigned long reclaim_options) 1253{ 1254 struct mem_cgroup *victim; 1255 int ret, total = 0; 1256 int loop = 0; 1257 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP; 1258 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK; 1259 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT; 1260 unsigned long excess = mem_cgroup_get_excess(root_mem); 1261 1262 /* If memsw_is_minimum==1, swap-out is of-no-use. */ 1263 if (root_mem->memsw_is_minimum) 1264 noswap = true; 1265 1266 while (1) { 1267 victim = mem_cgroup_select_victim(root_mem); 1268 if (victim == root_mem) { 1269 loop++; 1270 if (loop >= 1) 1271 drain_all_stock_async(); 1272 if (loop >= 2) { 1273 /* 1274 * If we have not been able to reclaim 1275 * anything, it might because there are 1276 * no reclaimable pages under this hierarchy 1277 */ 1278 if (!check_soft || !total) { 1279 css_put(&victim->css); 1280 break; 1281 } 1282 /* 1283 * We want to do more targetted reclaim. 1284 * excess >> 2 is not to excessive so as to 1285 * reclaim too much, nor too less that we keep 1286 * coming back to reclaim from this cgroup 1287 */ 1288 if (total >= (excess >> 2) || 1289 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) { 1290 css_put(&victim->css); 1291 break; 1292 } 1293 } 1294 } 1295 if (!mem_cgroup_local_usage(victim)) { 1296 /* this cgroup's local usage == 0 */ 1297 css_put(&victim->css); 1298 continue; 1299 } 1300 /* we use swappiness of local cgroup */ 1301 if (check_soft) 1302 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, 1303 noswap, get_swappiness(victim), zone); 1304 else 1305 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, 1306 noswap, get_swappiness(victim)); 1307 css_put(&victim->css); 1308 /* 1309 * At shrinking usage, we can't check we should stop here or 1310 * reclaim more. It's depends on callers. last_scanned_child 1311 * will work enough for keeping fairness under tree. 1312 */ 1313 if (shrink) 1314 return ret; 1315 total += ret; 1316 if (check_soft) { 1317 if (res_counter_check_under_soft_limit(&root_mem->res)) 1318 return total; 1319 } else if (mem_cgroup_check_under_limit(root_mem)) 1320 return 1 + total; 1321 } 1322 return total; 1323} 1324 1325static int mem_cgroup_oom_lock_cb(struct mem_cgroup *mem, void *data) 1326{ 1327 int *val = (int *)data; 1328 int x; 1329 /* 1330 * Logically, we can stop scanning immediately when we find 1331 * a memcg is already locked. But condidering unlock ops and 1332 * creation/removal of memcg, scan-all is simple operation. 1333 */ 1334 x = atomic_inc_return(&mem->oom_lock); 1335 *val = max(x, *val); 1336 return 0; 1337} 1338/* 1339 * Check OOM-Killer is already running under our hierarchy. 1340 * If someone is running, return false. 1341 */ 1342static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) 1343{ 1344 int lock_count = 0; 1345 1346 mem_cgroup_walk_tree(mem, &lock_count, mem_cgroup_oom_lock_cb); 1347 1348 if (lock_count == 1) 1349 return true; 1350 return false; 1351} 1352 1353static int mem_cgroup_oom_unlock_cb(struct mem_cgroup *mem, void *data) 1354{ 1355 /* 1356 * When a new child is created while the hierarchy is under oom, 1357 * mem_cgroup_oom_lock() may not be called. We have to use 1358 * atomic_add_unless() here. 1359 */ 1360 atomic_add_unless(&mem->oom_lock, -1, 0); 1361 return 0; 1362} 1363 1364static void mem_cgroup_oom_unlock(struct mem_cgroup *mem) 1365{ 1366 mem_cgroup_walk_tree(mem, NULL, mem_cgroup_oom_unlock_cb); 1367} 1368 1369static DEFINE_MUTEX(memcg_oom_mutex); 1370static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); 1371 1372struct oom_wait_info { 1373 struct mem_cgroup *mem; 1374 wait_queue_t wait; 1375}; 1376 1377static int memcg_oom_wake_function(wait_queue_t *wait, 1378 unsigned mode, int sync, void *arg) 1379{ 1380 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg; 1381 struct oom_wait_info *oom_wait_info; 1382 1383 oom_wait_info = container_of(wait, struct oom_wait_info, wait); 1384 1385 if (oom_wait_info->mem == wake_mem) 1386 goto wakeup; 1387 /* if no hierarchy, no match */ 1388 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy) 1389 return 0; 1390 /* 1391 * Both of oom_wait_info->mem and wake_mem are stable under us. 1392 * Then we can use css_is_ancestor without taking care of RCU. 1393 */ 1394 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && 1395 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) 1396 return 0; 1397 1398wakeup: 1399 return autoremove_wake_function(wait, mode, sync, arg); 1400} 1401 1402static void memcg_wakeup_oom(struct mem_cgroup *mem) 1403{ 1404 /* for filtering, pass "mem" as argument. */ 1405 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem); 1406} 1407 1408static void memcg_oom_recover(struct mem_cgroup *mem) 1409{ 1410 if (mem && atomic_read(&mem->oom_lock)) 1411 memcg_wakeup_oom(mem); 1412} 1413 1414/* 1415 * try to call OOM killer. returns false if we should exit memory-reclaim loop. 1416 */ 1417bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) 1418{ 1419 struct oom_wait_info owait; 1420 bool locked, need_to_kill; 1421 1422 owait.mem = mem; 1423 owait.wait.flags = 0; 1424 owait.wait.func = memcg_oom_wake_function; 1425 owait.wait.private = current; 1426 INIT_LIST_HEAD(&owait.wait.task_list); 1427 need_to_kill = true; 1428 /* At first, try to OOM lock hierarchy under mem.*/ 1429 mutex_lock(&memcg_oom_mutex); 1430 locked = mem_cgroup_oom_lock(mem); 1431 /* 1432 * Even if signal_pending(), we can't quit charge() loop without 1433 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL 1434 * under OOM is always welcomed, use TASK_KILLABLE here. 1435 */ 1436 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); 1437 if (!locked || mem->oom_kill_disable) 1438 need_to_kill = false; 1439 if (locked) 1440 mem_cgroup_oom_notify(mem); 1441 mutex_unlock(&memcg_oom_mutex); 1442 1443 if (need_to_kill) { 1444 finish_wait(&memcg_oom_waitq, &owait.wait); 1445 mem_cgroup_out_of_memory(mem, mask); 1446 } else { 1447 schedule(); 1448 finish_wait(&memcg_oom_waitq, &owait.wait); 1449 } 1450 mutex_lock(&memcg_oom_mutex); 1451 mem_cgroup_oom_unlock(mem); 1452 memcg_wakeup_oom(mem); 1453 mutex_unlock(&memcg_oom_mutex); 1454 1455 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) 1456 return false; 1457 /* Give chance to dying process */ 1458 schedule_timeout(1); 1459 return true; 1460} 1461 1462/* 1463 * Currently used to update mapped file statistics, but the routine can be 1464 * generalized to update other statistics as well. 1465 */ 1466void mem_cgroup_update_file_mapped(struct page *page, int val) 1467{ 1468 struct mem_cgroup *mem; 1469 struct page_cgroup *pc; 1470 1471 pc = lookup_page_cgroup(page); 1472 if (unlikely(!pc)) 1473 return; 1474 1475 lock_page_cgroup(pc); 1476 mem = pc->mem_cgroup; 1477 if (!mem || !PageCgroupUsed(pc)) 1478 goto done; 1479 1480 /* 1481 * Preemption is already disabled. We can use __this_cpu_xxx 1482 */ 1483 if (val > 0) { 1484 __this_cpu_inc(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 1485 SetPageCgroupFileMapped(pc); 1486 } else { 1487 __this_cpu_dec(mem->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 1488 ClearPageCgroupFileMapped(pc); 1489 } 1490 1491done: 1492 unlock_page_cgroup(pc); 1493} 1494 1495/* 1496 * size of first charge trial. "32" comes from vmscan.c's magic value. 1497 * TODO: maybe necessary to use big numbers in big irons. 1498 */ 1499#define CHARGE_SIZE (32 * PAGE_SIZE) 1500struct memcg_stock_pcp { 1501 struct mem_cgroup *cached; /* this never be root cgroup */ 1502 int charge; 1503 struct work_struct work; 1504}; 1505static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); 1506static atomic_t memcg_drain_count; 1507 1508/* 1509 * Try to consume stocked charge on this cpu. If success, PAGE_SIZE is consumed 1510 * from local stock and true is returned. If the stock is 0 or charges from a 1511 * cgroup which is not current target, returns false. This stock will be 1512 * refilled. 1513 */ 1514static bool consume_stock(struct mem_cgroup *mem) 1515{ 1516 struct memcg_stock_pcp *stock; 1517 bool ret = true; 1518 1519 stock = &get_cpu_var(memcg_stock); 1520 if (mem == stock->cached && stock->charge) 1521 stock->charge -= PAGE_SIZE; 1522 else /* need to call res_counter_charge */ 1523 ret = false; 1524 put_cpu_var(memcg_stock); 1525 return ret; 1526} 1527 1528/* 1529 * Returns stocks cached in percpu to res_counter and reset cached information. 1530 */ 1531static void drain_stock(struct memcg_stock_pcp *stock) 1532{ 1533 struct mem_cgroup *old = stock->cached; 1534 1535 if (stock->charge) { 1536 res_counter_uncharge(&old->res, stock->charge); 1537 if (do_swap_account) 1538 res_counter_uncharge(&old->memsw, stock->charge); 1539 } 1540 stock->cached = NULL; 1541 stock->charge = 0; 1542} 1543 1544/* 1545 * This must be called under preempt disabled or must be called by 1546 * a thread which is pinned to local cpu. 1547 */ 1548static void drain_local_stock(struct work_struct *dummy) 1549{ 1550 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); 1551 drain_stock(stock); 1552} 1553 1554/* 1555 * Cache charges(val) which is from res_counter, to local per_cpu area. 1556 * This will be consumed by consume_stock() function, later. 1557 */ 1558static void refill_stock(struct mem_cgroup *mem, int val) 1559{ 1560 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); 1561 1562 if (stock->cached != mem) { /* reset if necessary */ 1563 drain_stock(stock); 1564 stock->cached = mem; 1565 } 1566 stock->charge += val; 1567 put_cpu_var(memcg_stock); 1568} 1569 1570/* 1571 * Tries to drain stocked charges in other cpus. This function is asynchronous 1572 * and just put a work per cpu for draining localy on each cpu. Caller can 1573 * expects some charges will be back to res_counter later but cannot wait for 1574 * it. 1575 */ 1576static void drain_all_stock_async(void) 1577{ 1578 int cpu; 1579 /* This function is for scheduling "drain" in asynchronous way. 1580 * The result of "drain" is not directly handled by callers. Then, 1581 * if someone is calling drain, we don't have to call drain more. 1582 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if 1583 * there is a race. We just do loose check here. 1584 */ 1585 if (atomic_read(&memcg_drain_count)) 1586 return; 1587 /* Notify other cpus that system-wide "drain" is running */ 1588 atomic_inc(&memcg_drain_count); 1589 get_online_cpus(); 1590 for_each_online_cpu(cpu) { 1591 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); 1592 schedule_work_on(cpu, &stock->work); 1593 } 1594 put_online_cpus(); 1595 atomic_dec(&memcg_drain_count); 1596 /* We don't wait for flush_work */ 1597} 1598 1599/* This is a synchronous drain interface. */ 1600static void drain_all_stock_sync(void) 1601{ 1602 /* called when force_empty is called */ 1603 atomic_inc(&memcg_drain_count); 1604 schedule_on_each_cpu(drain_local_stock); 1605 atomic_dec(&memcg_drain_count); 1606} 1607 1608static int __cpuinit memcg_stock_cpu_callback(struct notifier_block *nb, 1609 unsigned long action, 1610 void *hcpu) 1611{ 1612 int cpu = (unsigned long)hcpu; 1613 struct memcg_stock_pcp *stock; 1614 1615 if (action != CPU_DEAD) 1616 return NOTIFY_OK; 1617 stock = &per_cpu(memcg_stock, cpu); 1618 drain_stock(stock); 1619 return NOTIFY_OK; 1620} 1621 1622 1623/* See __mem_cgroup_try_charge() for details */ 1624enum { 1625 CHARGE_OK, /* success */ 1626 CHARGE_RETRY, /* need to retry but retry is not bad */ 1627 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ 1628 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ 1629 CHARGE_OOM_DIE, /* the current is killed because of OOM */ 1630}; 1631 1632static int __mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask, 1633 int csize, bool oom_check) 1634{ 1635 struct mem_cgroup *mem_over_limit; 1636 struct res_counter *fail_res; 1637 unsigned long flags = 0; 1638 int ret; 1639 1640 ret = res_counter_charge(&mem->res, csize, &fail_res); 1641 1642 if (likely(!ret)) { 1643 if (!do_swap_account) 1644 return CHARGE_OK; 1645 ret = res_counter_charge(&mem->memsw, csize, &fail_res); 1646 if (likely(!ret)) 1647 return CHARGE_OK; 1648 1649 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); 1650 flags |= MEM_CGROUP_RECLAIM_NOSWAP; 1651 } else 1652 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); 1653 1654 if (csize > PAGE_SIZE) /* change csize and retry */ 1655 return CHARGE_RETRY; 1656 1657 if (!(gfp_mask & __GFP_WAIT)) 1658 return CHARGE_WOULDBLOCK; 1659 1660 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, 1661 gfp_mask, flags); 1662 /* 1663 * try_to_free_mem_cgroup_pages() might not give us a full 1664 * picture of reclaim. Some pages are reclaimed and might be 1665 * moved to swap cache or just unmapped from the cgroup. 1666 * Check the limit again to see if the reclaim reduced the 1667 * current usage of the cgroup before giving up 1668 */ 1669 if (ret || mem_cgroup_check_under_limit(mem_over_limit)) 1670 return CHARGE_RETRY; 1671 1672 /* 1673 * At task move, charge accounts can be doubly counted. So, it's 1674 * better to wait until the end of task_move if something is going on. 1675 */ 1676 if (mem_cgroup_wait_acct_move(mem_over_limit)) 1677 return CHARGE_RETRY; 1678 1679 /* If we don't need to call oom-killer at el, return immediately */ 1680 if (!oom_check) 1681 return CHARGE_NOMEM; 1682 /* check OOM */ 1683 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) 1684 return CHARGE_OOM_DIE; 1685 1686 return CHARGE_RETRY; 1687} 1688 1689/* 1690 * Unlike exported interface, "oom" parameter is added. if oom==true, 1691 * oom-killer can be invoked. 1692 */ 1693static int __mem_cgroup_try_charge(struct mm_struct *mm, 1694 gfp_t gfp_mask, struct mem_cgroup **memcg, bool oom) 1695{ 1696 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 1697 struct mem_cgroup *mem = NULL; 1698 int ret; 1699 int csize = CHARGE_SIZE; 1700 1701 /* 1702 * Unlike gloval-vm's OOM-kill, we're not in memory shortage 1703 * in system level. So, allow to go ahead dying process in addition to 1704 * MEMDIE process. 1705 */ 1706 if (unlikely(test_thread_flag(TIF_MEMDIE) 1707 || fatal_signal_pending(current))) 1708 goto bypass; 1709 1710 /* 1711 * We always charge the cgroup the mm_struct belongs to. 1712 * The mm_struct's mem_cgroup changes on task migration if the 1713 * thread group leader migrates. It's possible that mm is not 1714 * set, if so charge the init_mm (happens for pagecache usage). 1715 */ 1716 if (!*memcg && !mm) 1717 goto bypass; 1718again: 1719 if (*memcg) { /* css should be a valid one */ 1720 mem = *memcg; 1721 VM_BUG_ON(css_is_removed(&mem->css)); 1722 if (mem_cgroup_is_root(mem)) 1723 goto done; 1724 if (consume_stock(mem)) 1725 goto done; 1726 css_get(&mem->css); 1727 } else { 1728 struct task_struct *p; 1729 1730 rcu_read_lock(); 1731 p = rcu_dereference(mm->owner); 1732 VM_BUG_ON(!p); 1733 /* 1734 * because we don't have task_lock(), "p" can exit while 1735 * we're here. In that case, "mem" can point to root 1736 * cgroup but never be NULL. (and task_struct itself is freed 1737 * by RCU, cgroup itself is RCU safe.) Then, we have small 1738 * risk here to get wrong cgroup. But such kind of mis-account 1739 * by race always happens because we don't have cgroup_mutex(). 1740 * It's overkill and we allow that small race, here. 1741 */ 1742 mem = mem_cgroup_from_task(p); 1743 VM_BUG_ON(!mem); 1744 if (mem_cgroup_is_root(mem)) { 1745 rcu_read_unlock(); 1746 goto done; 1747 } 1748 if (consume_stock(mem)) { 1749 /* 1750 * It seems dagerous to access memcg without css_get(). 1751 * But considering how consume_stok works, it's not 1752 * necessary. If consume_stock success, some charges 1753 * from this memcg are cached on this cpu. So, we 1754 * don't need to call css_get()/css_tryget() before 1755 * calling consume_stock(). 1756 */ 1757 rcu_read_unlock(); 1758 goto done; 1759 } 1760 /* after here, we may be blocked. we need to get refcnt */ 1761 if (!css_tryget(&mem->css)) { 1762 rcu_read_unlock(); 1763 goto again; 1764 } 1765 rcu_read_unlock(); 1766 } 1767 1768 do { 1769 bool oom_check; 1770 1771 /* If killed, bypass charge */ 1772 if (fatal_signal_pending(current)) { 1773 css_put(&mem->css); 1774 goto bypass; 1775 } 1776 1777 oom_check = false; 1778 if (oom && !nr_oom_retries) { 1779 oom_check = true; 1780 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 1781 } 1782 1783 ret = __mem_cgroup_do_charge(mem, gfp_mask, csize, oom_check); 1784 1785 switch (ret) { 1786 case CHARGE_OK: 1787 break; 1788 case CHARGE_RETRY: /* not in OOM situation but retry */ 1789 csize = PAGE_SIZE; 1790 css_put(&mem->css); 1791 mem = NULL; 1792 goto again; 1793 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ 1794 css_put(&mem->css); 1795 goto nomem; 1796 case CHARGE_NOMEM: /* OOM routine works */ 1797 if (!oom) { 1798 css_put(&mem->css); 1799 goto nomem; 1800 } 1801 /* If oom, we never return -ENOMEM */ 1802 nr_oom_retries--; 1803 break; 1804 case CHARGE_OOM_DIE: /* Killed by OOM Killer */ 1805 css_put(&mem->css); 1806 goto bypass; 1807 } 1808 } while (ret != CHARGE_OK); 1809 1810 if (csize > PAGE_SIZE) 1811 refill_stock(mem, csize - PAGE_SIZE); 1812 css_put(&mem->css); 1813done: 1814 *memcg = mem; 1815 return 0; 1816nomem: 1817 *memcg = NULL; 1818 return -ENOMEM; 1819bypass: 1820 *memcg = NULL; 1821 return 0; 1822} 1823 1824/* 1825 * Somemtimes we have to undo a charge we got by try_charge(). 1826 * This function is for that and do uncharge, put css's refcnt. 1827 * gotten by try_charge(). 1828 */ 1829static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem, 1830 unsigned long count) 1831{ 1832 if (!mem_cgroup_is_root(mem)) { 1833 res_counter_uncharge(&mem->res, PAGE_SIZE * count); 1834 if (do_swap_account) 1835 res_counter_uncharge(&mem->memsw, PAGE_SIZE * count); 1836 } 1837} 1838 1839static void mem_cgroup_cancel_charge(struct mem_cgroup *mem) 1840{ 1841 __mem_cgroup_cancel_charge(mem, 1); 1842} 1843 1844/* 1845 * A helper function to get mem_cgroup from ID. must be called under 1846 * rcu_read_lock(). The caller must check css_is_removed() or some if 1847 * it's concern. (dropping refcnt from swap can be called against removed 1848 * memcg.) 1849 */ 1850static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) 1851{ 1852 struct cgroup_subsys_state *css; 1853 1854 /* ID 0 is unused ID */ 1855 if (!id) 1856 return NULL; 1857 css = css_lookup(&mem_cgroup_subsys, id); 1858 if (!css) 1859 return NULL; 1860 return container_of(css, struct mem_cgroup, css); 1861} 1862 1863struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) 1864{ 1865 struct mem_cgroup *mem = NULL; 1866 struct page_cgroup *pc; 1867 unsigned short id; 1868 swp_entry_t ent; 1869 1870 VM_BUG_ON(!PageLocked(page)); 1871 1872 pc = lookup_page_cgroup(page); 1873 lock_page_cgroup(pc); 1874 if (PageCgroupUsed(pc)) { 1875 mem = pc->mem_cgroup; 1876 if (mem && !css_tryget(&mem->css)) 1877 mem = NULL; 1878 } else if (PageSwapCache(page)) { 1879 ent.val = page_private(page); 1880 id = lookup_swap_cgroup(ent); 1881 rcu_read_lock(); 1882 mem = mem_cgroup_lookup(id); 1883 if (mem && !css_tryget(&mem->css)) 1884 mem = NULL; 1885 rcu_read_unlock(); 1886 } 1887 unlock_page_cgroup(pc); 1888 return mem; 1889} 1890 1891/* 1892 * commit a charge got by __mem_cgroup_try_charge() and makes page_cgroup to be 1893 * USED state. If already USED, uncharge and return. 1894 */ 1895 1896static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, 1897 struct page_cgroup *pc, 1898 enum charge_type ctype) 1899{ 1900 /* try_charge() can return NULL to *memcg, taking care of it. */ 1901 if (!mem) 1902 return; 1903 1904 lock_page_cgroup(pc); 1905 if (unlikely(PageCgroupUsed(pc))) { 1906 unlock_page_cgroup(pc); 1907 mem_cgroup_cancel_charge(mem); 1908 return; 1909 } 1910 1911 pc->mem_cgroup = mem; 1912 /* 1913 * We access a page_cgroup asynchronously without lock_page_cgroup(). 1914 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup 1915 * is accessed after testing USED bit. To make pc->mem_cgroup visible 1916 * before USED bit, we need memory barrier here. 1917 * See mem_cgroup_add_lru_list(), etc. 1918 */ 1919 smp_wmb(); 1920 switch (ctype) { 1921 case MEM_CGROUP_CHARGE_TYPE_CACHE: 1922 case MEM_CGROUP_CHARGE_TYPE_SHMEM: 1923 SetPageCgroupCache(pc); 1924 SetPageCgroupUsed(pc); 1925 break; 1926 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 1927 ClearPageCgroupCache(pc); 1928 SetPageCgroupUsed(pc); 1929 break; 1930 default: 1931 break; 1932 } 1933 1934 mem_cgroup_charge_statistics(mem, pc, true); 1935 1936 unlock_page_cgroup(pc); 1937 /* 1938 * "charge_statistics" updated event counter. Then, check it. 1939 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. 1940 * if they exceeds softlimit. 1941 */ 1942 memcg_check_events(mem, pc->page); 1943} 1944 1945/** 1946 * __mem_cgroup_move_account - move account of the page 1947 * @pc: page_cgroup of the page. 1948 * @from: mem_cgroup which the page is moved from. 1949 * @to: mem_cgroup which the page is moved to. @from != @to. 1950 * @uncharge: whether we should call uncharge and css_put against @from. 1951 * 1952 * The caller must confirm following. 1953 * - page is not on LRU (isolate_page() is useful.) 1954 * - the pc is locked, used, and ->mem_cgroup points to @from. 1955 * 1956 * This function doesn't do "charge" nor css_get to new cgroup. It should be 1957 * done by a caller(__mem_cgroup_try_charge would be usefull). If @uncharge is 1958 * true, this function does "uncharge" from old cgroup, but it doesn't if 1959 * @uncharge is false, so a caller should do "uncharge". 1960 */ 1961 1962static void __mem_cgroup_move_account(struct page_cgroup *pc, 1963 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge) 1964{ 1965 VM_BUG_ON(from == to); 1966 VM_BUG_ON(PageLRU(pc->page)); 1967 VM_BUG_ON(!PageCgroupLocked(pc)); 1968 VM_BUG_ON(!PageCgroupUsed(pc)); 1969 VM_BUG_ON(pc->mem_cgroup != from); 1970 1971 if (PageCgroupFileMapped(pc)) { 1972 /* Update mapped_file data for mem_cgroup */ 1973 preempt_disable(); 1974 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 1975 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 1976 preempt_enable(); 1977 } 1978 mem_cgroup_charge_statistics(from, pc, false); 1979 if (uncharge) 1980 /* This is not "cancel", but cancel_charge does all we need. */ 1981 mem_cgroup_cancel_charge(from); 1982 1983 /* caller should have done css_get */ 1984 pc->mem_cgroup = to; 1985 mem_cgroup_charge_statistics(to, pc, true); 1986 /* 1987 * We charges against "to" which may not have any tasks. Then, "to" 1988 * can be under rmdir(). But in current implementation, caller of 1989 * this function is just force_empty() and move charge, so it's 1990 * garanteed that "to" is never removed. So, we don't check rmdir 1991 * status here. 1992 */ 1993} 1994 1995/* 1996 * check whether the @pc is valid for moving account and call 1997 * __mem_cgroup_move_account() 1998 */ 1999static int mem_cgroup_move_account(struct page_cgroup *pc, 2000 struct mem_cgroup *from, struct mem_cgroup *to, bool uncharge) 2001{ 2002 int ret = -EINVAL; 2003 lock_page_cgroup(pc); 2004 if (PageCgroupUsed(pc) && pc->mem_cgroup == from) { 2005 __mem_cgroup_move_account(pc, from, to, uncharge); 2006 ret = 0; 2007 } 2008 unlock_page_cgroup(pc); 2009 /* 2010 * check events 2011 */ 2012 memcg_check_events(to, pc->page); 2013 memcg_check_events(from, pc->page); 2014 return ret; 2015} 2016 2017/* 2018 * move charges to its parent. 2019 */ 2020 2021static int mem_cgroup_move_parent(struct page_cgroup *pc, 2022 struct mem_cgroup *child, 2023 gfp_t gfp_mask) 2024{ 2025 struct page *page = pc->page; 2026 struct cgroup *cg = child->css.cgroup; 2027 struct cgroup *pcg = cg->parent; 2028 struct mem_cgroup *parent; 2029 int ret; 2030 2031 /* Is ROOT ? */ 2032 if (!pcg) 2033 return -EINVAL; 2034 2035 ret = -EBUSY; 2036 if (!get_page_unless_zero(page)) 2037 goto out; 2038 if (isolate_lru_page(page)) 2039 goto put; 2040 2041 parent = mem_cgroup_from_cont(pcg); 2042 ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false); 2043 if (ret || !parent) 2044 goto put_back; 2045 2046 ret = mem_cgroup_move_account(pc, child, parent, true); 2047 if (ret) 2048 mem_cgroup_cancel_charge(parent); 2049put_back: 2050 putback_lru_page(page); 2051put: 2052 put_page(page); 2053out: 2054 return ret; 2055} 2056 2057/* 2058 * Charge the memory controller for page usage. 2059 * Return 2060 * 0 if the charge was successful 2061 * < 0 if the cgroup is over its limit 2062 */ 2063static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 2064 gfp_t gfp_mask, enum charge_type ctype) 2065{ 2066 struct mem_cgroup *mem = NULL; 2067 struct page_cgroup *pc; 2068 int ret; 2069 2070 pc = lookup_page_cgroup(page); 2071 /* can happen at boot */ 2072 if (unlikely(!pc)) 2073 return 0; 2074 prefetchw(pc); 2075 2076 ret = __mem_cgroup_try_charge(mm, gfp_mask, &mem, true); 2077 if (ret || !mem) 2078 return ret; 2079 2080 __mem_cgroup_commit_charge(mem, pc, ctype); 2081 return 0; 2082} 2083 2084int mem_cgroup_newpage_charge(struct page *page, 2085 struct mm_struct *mm, gfp_t gfp_mask) 2086{ 2087 if (mem_cgroup_disabled()) 2088 return 0; 2089 if (PageCompound(page)) 2090 return 0; 2091 /* 2092 * If already mapped, we don't have to account. 2093 * If page cache, page->mapping has address_space. 2094 * But page->mapping may have out-of-use anon_vma pointer, 2095 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping 2096 * is NULL. 2097 */ 2098 if (page_mapped(page) || (page->mapping && !PageAnon(page))) 2099 return 0; 2100 if (unlikely(!mm)) 2101 mm = &init_mm; 2102 return mem_cgroup_charge_common(page, mm, gfp_mask, 2103 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2104} 2105 2106static void 2107__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2108 enum charge_type ctype); 2109 2110int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 2111 gfp_t gfp_mask) 2112{ 2113 int ret; 2114 2115 if (mem_cgroup_disabled()) 2116 return 0; 2117 if (PageCompound(page)) 2118 return 0; 2119 /* 2120 * Corner case handling. This is called from add_to_page_cache() 2121 * in usual. But some FS (shmem) precharges this page before calling it 2122 * and call add_to_page_cache() with GFP_NOWAIT. 2123 * 2124 * For GFP_NOWAIT case, the page may be pre-charged before calling 2125 * add_to_page_cache(). (See shmem.c) check it here and avoid to call 2126 * charge twice. (It works but has to pay a bit larger cost.) 2127 * And when the page is SwapCache, it should take swap information 2128 * into account. This is under lock_page() now. 2129 */ 2130 if (!(gfp_mask & __GFP_WAIT)) { 2131 struct page_cgroup *pc; 2132 2133 pc = lookup_page_cgroup(page); 2134 if (!pc) 2135 return 0; 2136 lock_page_cgroup(pc); 2137 if (PageCgroupUsed(pc)) { 2138 unlock_page_cgroup(pc); 2139 return 0; 2140 } 2141 unlock_page_cgroup(pc); 2142 } 2143 2144 if (unlikely(!mm)) 2145 mm = &init_mm; 2146 2147 if (page_is_file_cache(page)) 2148 return mem_cgroup_charge_common(page, mm, gfp_mask, 2149 MEM_CGROUP_CHARGE_TYPE_CACHE); 2150 2151 /* shmem */ 2152 if (PageSwapCache(page)) { 2153 struct mem_cgroup *mem = NULL; 2154 2155 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); 2156 if (!ret) 2157 __mem_cgroup_commit_charge_swapin(page, mem, 2158 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2159 } else 2160 ret = mem_cgroup_charge_common(page, mm, gfp_mask, 2161 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2162 2163 return ret; 2164} 2165 2166/* 2167 * While swap-in, try_charge -> commit or cancel, the page is locked. 2168 * And when try_charge() successfully returns, one refcnt to memcg without 2169 * struct page_cgroup is acquired. This refcnt will be consumed by 2170 * "commit()" or removed by "cancel()" 2171 */ 2172int mem_cgroup_try_charge_swapin(struct mm_struct *mm, 2173 struct page *page, 2174 gfp_t mask, struct mem_cgroup **ptr) 2175{ 2176 struct mem_cgroup *mem; 2177 int ret; 2178 2179 if (mem_cgroup_disabled()) 2180 return 0; 2181 2182 if (!do_swap_account) 2183 goto charge_cur_mm; 2184 /* 2185 * A racing thread's fault, or swapoff, may have already updated 2186 * the pte, and even removed page from swap cache: in those cases 2187 * do_swap_page()'s pte_same() test will fail; but there's also a 2188 * KSM case which does need to charge the page. 2189 */ 2190 if (!PageSwapCache(page)) 2191 goto charge_cur_mm; 2192 mem = try_get_mem_cgroup_from_page(page); 2193 if (!mem) 2194 goto charge_cur_mm; 2195 *ptr = mem; 2196 ret = __mem_cgroup_try_charge(NULL, mask, ptr, true); 2197 css_put(&mem->css); 2198 return ret; 2199charge_cur_mm: 2200 if (unlikely(!mm)) 2201 mm = &init_mm; 2202 return __mem_cgroup_try_charge(mm, mask, ptr, true); 2203} 2204 2205static void 2206__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2207 enum charge_type ctype) 2208{ 2209 struct page_cgroup *pc; 2210 2211 if (mem_cgroup_disabled()) 2212 return; 2213 if (!ptr) 2214 return; 2215 cgroup_exclude_rmdir(&ptr->css); 2216 pc = lookup_page_cgroup(page); 2217 mem_cgroup_lru_del_before_commit_swapcache(page); 2218 __mem_cgroup_commit_charge(ptr, pc, ctype); 2219 mem_cgroup_lru_add_after_commit_swapcache(page); 2220 /* 2221 * Now swap is on-memory. This means this page may be 2222 * counted both as mem and swap....double count. 2223 * Fix it by uncharging from memsw. Basically, this SwapCache is stable 2224 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() 2225 * may call delete_from_swap_cache() before reach here. 2226 */ 2227 if (do_swap_account && PageSwapCache(page)) { 2228 swp_entry_t ent = {.val = page_private(page)}; 2229 unsigned short id; 2230 struct mem_cgroup *memcg; 2231 2232 id = swap_cgroup_record(ent, 0); 2233 rcu_read_lock(); 2234 memcg = mem_cgroup_lookup(id); 2235 if (memcg) { 2236 /* 2237 * This recorded memcg can be obsolete one. So, avoid 2238 * calling css_tryget 2239 */ 2240 if (!mem_cgroup_is_root(memcg)) 2241 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 2242 mem_cgroup_swap_statistics(memcg, false); 2243 mem_cgroup_put(memcg); 2244 } 2245 rcu_read_unlock(); 2246 } 2247 /* 2248 * At swapin, we may charge account against cgroup which has no tasks. 2249 * So, rmdir()->pre_destroy() can be called while we do this charge. 2250 * In that case, we need to call pre_destroy() again. check it here. 2251 */ 2252 cgroup_release_and_wakeup_rmdir(&ptr->css); 2253} 2254 2255void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) 2256{ 2257 __mem_cgroup_commit_charge_swapin(page, ptr, 2258 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2259} 2260 2261void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) 2262{ 2263 if (mem_cgroup_disabled()) 2264 return; 2265 if (!mem) 2266 return; 2267 mem_cgroup_cancel_charge(mem); 2268} 2269 2270static void 2271__do_uncharge(struct mem_cgroup *mem, const enum charge_type ctype) 2272{ 2273 struct memcg_batch_info *batch = NULL; 2274 bool uncharge_memsw = true; 2275 /* If swapout, usage of swap doesn't decrease */ 2276 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) 2277 uncharge_memsw = false; 2278 2279 batch = ¤t->memcg_batch; 2280 /* 2281 * In usual, we do css_get() when we remember memcg pointer. 2282 * But in this case, we keep res->usage until end of a series of 2283 * uncharges. Then, it's ok to ignore memcg's refcnt. 2284 */ 2285 if (!batch->memcg) 2286 batch->memcg = mem; 2287 /* 2288 * do_batch > 0 when unmapping pages or inode invalidate/truncate. 2289 * In those cases, all pages freed continously can be expected to be in 2290 * the same cgroup and we have chance to coalesce uncharges. 2291 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) 2292 * because we want to do uncharge as soon as possible. 2293 */ 2294 2295 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) 2296 goto direct_uncharge; 2297 2298 /* 2299 * In typical case, batch->memcg == mem. This means we can 2300 * merge a series of uncharges to an uncharge of res_counter. 2301 * If not, we uncharge res_counter ony by one. 2302 */ 2303 if (batch->memcg != mem) 2304 goto direct_uncharge; 2305 /* remember freed charge and uncharge it later */ 2306 batch->bytes += PAGE_SIZE; 2307 if (uncharge_memsw) 2308 batch->memsw_bytes += PAGE_SIZE; 2309 return; 2310direct_uncharge: 2311 res_counter_uncharge(&mem->res, PAGE_SIZE); 2312 if (uncharge_memsw) 2313 res_counter_uncharge(&mem->memsw, PAGE_SIZE); 2314 if (unlikely(batch->memcg != mem)) 2315 memcg_oom_recover(mem); 2316 return; 2317} 2318 2319/* 2320 * uncharge if !page_mapped(page) 2321 */ 2322static struct mem_cgroup * 2323__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) 2324{ 2325 struct page_cgroup *pc; 2326 struct mem_cgroup *mem = NULL; 2327 2328 if (mem_cgroup_disabled()) 2329 return NULL; 2330 2331 if (PageSwapCache(page)) 2332 return NULL; 2333 2334 /* 2335 * Check if our page_cgroup is valid 2336 */ 2337 pc = lookup_page_cgroup(page); 2338 if (unlikely(!pc || !PageCgroupUsed(pc))) 2339 return NULL; 2340 2341 lock_page_cgroup(pc); 2342 2343 mem = pc->mem_cgroup; 2344 2345 if (!PageCgroupUsed(pc)) 2346 goto unlock_out; 2347 2348 switch (ctype) { 2349 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 2350 case MEM_CGROUP_CHARGE_TYPE_DROP: 2351 /* See mem_cgroup_prepare_migration() */ 2352 if (page_mapped(page) || PageCgroupMigration(pc)) 2353 goto unlock_out; 2354 break; 2355 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: 2356 if (!PageAnon(page)) { /* Shared memory */ 2357 if (page->mapping && !page_is_file_cache(page)) 2358 goto unlock_out; 2359 } else if (page_mapped(page)) /* Anon */ 2360 goto unlock_out; 2361 break; 2362 default: 2363 break; 2364 } 2365 2366 mem_cgroup_charge_statistics(mem, pc, false); 2367 2368 ClearPageCgroupUsed(pc); 2369 /* 2370 * pc->mem_cgroup is not cleared here. It will be accessed when it's 2371 * freed from LRU. This is safe because uncharged page is expected not 2372 * to be reused (freed soon). Exception is SwapCache, it's handled by 2373 * special functions. 2374 */ 2375 2376 unlock_page_cgroup(pc); 2377 /* 2378 * even after unlock, we have mem->res.usage here and this memcg 2379 * will never be freed. 2380 */ 2381 memcg_check_events(mem, page); 2382 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { 2383 mem_cgroup_swap_statistics(mem, true); 2384 mem_cgroup_get(mem); 2385 } 2386 if (!mem_cgroup_is_root(mem)) 2387 __do_uncharge(mem, ctype); 2388 2389 return mem; 2390 2391unlock_out: 2392 unlock_page_cgroup(pc); 2393 return NULL; 2394} 2395 2396void mem_cgroup_uncharge_page(struct page *page) 2397{ 2398 /* early check. */ 2399 if (page_mapped(page)) 2400 return; 2401 if (page->mapping && !PageAnon(page)) 2402 return; 2403 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); 2404} 2405 2406void mem_cgroup_uncharge_cache_page(struct page *page) 2407{ 2408 VM_BUG_ON(page_mapped(page)); 2409 VM_BUG_ON(page->mapping); 2410 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); 2411} 2412 2413/* 2414 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. 2415 * In that cases, pages are freed continuously and we can expect pages 2416 * are in the same memcg. All these calls itself limits the number of 2417 * pages freed at once, then uncharge_start/end() is called properly. 2418 * This may be called prural(2) times in a context, 2419 */ 2420 2421void mem_cgroup_uncharge_start(void) 2422{ 2423 current->memcg_batch.do_batch++; 2424 /* We can do nest. */ 2425 if (current->memcg_batch.do_batch == 1) { 2426 current->memcg_batch.memcg = NULL; 2427 current->memcg_batch.bytes = 0; 2428 current->memcg_batch.memsw_bytes = 0; 2429 } 2430} 2431 2432void mem_cgroup_uncharge_end(void) 2433{ 2434 struct memcg_batch_info *batch = ¤t->memcg_batch; 2435 2436 if (!batch->do_batch) 2437 return; 2438 2439 batch->do_batch--; 2440 if (batch->do_batch) /* If stacked, do nothing. */ 2441 return; 2442 2443 if (!batch->memcg) 2444 return; 2445 /* 2446 * This "batch->memcg" is valid without any css_get/put etc... 2447 * bacause we hide charges behind us. 2448 */ 2449 if (batch->bytes) 2450 res_counter_uncharge(&batch->memcg->res, batch->bytes); 2451 if (batch->memsw_bytes) 2452 res_counter_uncharge(&batch->memcg->memsw, batch->memsw_bytes); 2453 memcg_oom_recover(batch->memcg); 2454 /* forget this pointer (for sanity check) */ 2455 batch->memcg = NULL; 2456} 2457 2458#ifdef CONFIG_SWAP 2459/* 2460 * called after __delete_from_swap_cache() and drop "page" account. 2461 * memcg information is recorded to swap_cgroup of "ent" 2462 */ 2463void 2464mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 2465{ 2466 struct mem_cgroup *memcg; 2467 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; 2468 2469 if (!swapout) /* this was a swap cache but the swap is unused ! */ 2470 ctype = MEM_CGROUP_CHARGE_TYPE_DROP; 2471 2472 memcg = __mem_cgroup_uncharge_common(page, ctype); 2473 2474 /* 2475 * record memcg information, if swapout && memcg != NULL, 2476 * mem_cgroup_get() was called in uncharge(). 2477 */ 2478 if (do_swap_account && swapout && memcg) 2479 swap_cgroup_record(ent, css_id(&memcg->css)); 2480} 2481#endif 2482 2483#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 2484/* 2485 * called from swap_entry_free(). remove record in swap_cgroup and 2486 * uncharge "memsw" account. 2487 */ 2488void mem_cgroup_uncharge_swap(swp_entry_t ent) 2489{ 2490 struct mem_cgroup *memcg; 2491 unsigned short id; 2492 2493 if (!do_swap_account) 2494 return; 2495 2496 id = swap_cgroup_record(ent, 0); 2497 rcu_read_lock(); 2498 memcg = mem_cgroup_lookup(id); 2499 if (memcg) { 2500 /* 2501 * We uncharge this because swap is freed. 2502 * This memcg can be obsolete one. We avoid calling css_tryget 2503 */ 2504 if (!mem_cgroup_is_root(memcg)) 2505 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 2506 mem_cgroup_swap_statistics(memcg, false); 2507 mem_cgroup_put(memcg); 2508 } 2509 rcu_read_unlock(); 2510} 2511 2512/** 2513 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. 2514 * @entry: swap entry to be moved 2515 * @from: mem_cgroup which the entry is moved from 2516 * @to: mem_cgroup which the entry is moved to 2517 * @need_fixup: whether we should fixup res_counters and refcounts. 2518 * 2519 * It succeeds only when the swap_cgroup's record for this entry is the same 2520 * as the mem_cgroup's id of @from. 2521 * 2522 * Returns 0 on success, -EINVAL on failure. 2523 * 2524 * The caller must have charged to @to, IOW, called res_counter_charge() about 2525 * both res and memsw, and called css_get(). 2526 */ 2527static int mem_cgroup_move_swap_account(swp_entry_t entry, 2528 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 2529{ 2530 unsigned short old_id, new_id; 2531 2532 old_id = css_id(&from->css); 2533 new_id = css_id(&to->css); 2534 2535 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { 2536 mem_cgroup_swap_statistics(from, false); 2537 mem_cgroup_swap_statistics(to, true); 2538 /* 2539 * This function is only called from task migration context now. 2540 * It postpones res_counter and refcount handling till the end 2541 * of task migration(mem_cgroup_clear_mc()) for performance 2542 * improvement. But we cannot postpone mem_cgroup_get(to) 2543 * because if the process that has been moved to @to does 2544 * swap-in, the refcount of @to might be decreased to 0. 2545 */ 2546 mem_cgroup_get(to); 2547 if (need_fixup) { 2548 if (!mem_cgroup_is_root(from)) 2549 res_counter_uncharge(&from->memsw, PAGE_SIZE); 2550 mem_cgroup_put(from); 2551 /* 2552 * we charged both to->res and to->memsw, so we should 2553 * uncharge to->res. 2554 */ 2555 if (!mem_cgroup_is_root(to)) 2556 res_counter_uncharge(&to->res, PAGE_SIZE); 2557 } 2558 return 0; 2559 } 2560 return -EINVAL; 2561} 2562#else 2563static inline int mem_cgroup_move_swap_account(swp_entry_t entry, 2564 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 2565{ 2566 return -EINVAL; 2567} 2568#endif 2569 2570/* 2571 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old 2572 * page belongs to. 2573 */ 2574int mem_cgroup_prepare_migration(struct page *page, 2575 struct page *newpage, struct mem_cgroup **ptr) 2576{ 2577 struct page_cgroup *pc; 2578 struct mem_cgroup *mem = NULL; 2579 enum charge_type ctype; 2580 int ret = 0; 2581 2582 if (mem_cgroup_disabled()) 2583 return 0; 2584 2585 pc = lookup_page_cgroup(page); 2586 lock_page_cgroup(pc); 2587 if (PageCgroupUsed(pc)) { 2588 mem = pc->mem_cgroup; 2589 css_get(&mem->css); 2590 /* 2591 * At migrating an anonymous page, its mapcount goes down 2592 * to 0 and uncharge() will be called. But, even if it's fully 2593 * unmapped, migration may fail and this page has to be 2594 * charged again. We set MIGRATION flag here and delay uncharge 2595 * until end_migration() is called 2596 * 2597 * Corner Case Thinking 2598 * A) 2599 * When the old page was mapped as Anon and it's unmap-and-freed 2600 * while migration was ongoing. 2601 * If unmap finds the old page, uncharge() of it will be delayed 2602 * until end_migration(). If unmap finds a new page, it's 2603 * uncharged when it make mapcount to be 1->0. If unmap code 2604 * finds swap_migration_entry, the new page will not be mapped 2605 * and end_migration() will find it(mapcount==0). 2606 * 2607 * B) 2608 * When the old page was mapped but migraion fails, the kernel 2609 * remaps it. A charge for it is kept by MIGRATION flag even 2610 * if mapcount goes down to 0. We can do remap successfully 2611 * without charging it again. 2612 * 2613 * C) 2614 * The "old" page is under lock_page() until the end of 2615 * migration, so, the old page itself will not be swapped-out. 2616 * If the new page is swapped out before end_migraton, our 2617 * hook to usual swap-out path will catch the event. 2618 */ 2619 if (PageAnon(page)) 2620 SetPageCgroupMigration(pc); 2621 } 2622 unlock_page_cgroup(pc); 2623 /* 2624 * If the page is not charged at this point, 2625 * we return here. 2626 */ 2627 if (!mem) 2628 return 0; 2629 2630 *ptr = mem; 2631 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, ptr, false); 2632 css_put(&mem->css);/* drop extra refcnt */ 2633 if (ret || *ptr == NULL) { 2634 if (PageAnon(page)) { 2635 lock_page_cgroup(pc); 2636 ClearPageCgroupMigration(pc); 2637 unlock_page_cgroup(pc); 2638 /* 2639 * The old page may be fully unmapped while we kept it. 2640 */ 2641 mem_cgroup_uncharge_page(page); 2642 } 2643 return -ENOMEM; 2644 } 2645 /* 2646 * We charge new page before it's used/mapped. So, even if unlock_page() 2647 * is called before end_migration, we can catch all events on this new 2648 * page. In the case new page is migrated but not remapped, new page's 2649 * mapcount will be finally 0 and we call uncharge in end_migration(). 2650 */ 2651 pc = lookup_page_cgroup(newpage); 2652 if (PageAnon(page)) 2653 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; 2654 else if (page_is_file_cache(page)) 2655 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; 2656 else 2657 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; 2658 __mem_cgroup_commit_charge(mem, pc, ctype); 2659 return ret; 2660} 2661 2662/* remove redundant charge if migration failed*/ 2663void mem_cgroup_end_migration(struct mem_cgroup *mem, 2664 struct page *oldpage, struct page *newpage) 2665{ 2666 struct page *used, *unused; 2667 struct page_cgroup *pc; 2668 2669 if (!mem) 2670 return; 2671 /* blocks rmdir() */ 2672 cgroup_exclude_rmdir(&mem->css); 2673 /* at migration success, oldpage->mapping is NULL. */ 2674 if (oldpage->mapping) { 2675 used = oldpage; 2676 unused = newpage; 2677 } else { 2678 used = newpage; 2679 unused = oldpage; 2680 } 2681 /* 2682 * We disallowed uncharge of pages under migration because mapcount 2683 * of the page goes down to zero, temporarly. 2684 * Clear the flag and check the page should be charged. 2685 */ 2686 pc = lookup_page_cgroup(oldpage); 2687 lock_page_cgroup(pc); 2688 ClearPageCgroupMigration(pc); 2689 unlock_page_cgroup(pc); 2690 2691 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE); 2692 2693 /* 2694 * If a page is a file cache, radix-tree replacement is very atomic 2695 * and we can skip this check. When it was an Anon page, its mapcount 2696 * goes down to 0. But because we added MIGRATION flage, it's not 2697 * uncharged yet. There are several case but page->mapcount check 2698 * and USED bit check in mem_cgroup_uncharge_page() will do enough 2699 * check. (see prepare_charge() also) 2700 */ 2701 if (PageAnon(used)) 2702 mem_cgroup_uncharge_page(used); 2703 /* 2704 * At migration, we may charge account against cgroup which has no 2705 * tasks. 2706 * So, rmdir()->pre_destroy() can be called while we do this charge. 2707 * In that case, we need to call pre_destroy() again. check it here. 2708 */ 2709 cgroup_release_and_wakeup_rmdir(&mem->css); 2710} 2711 2712/* 2713 * A call to try to shrink memory usage on charge failure at shmem's swapin. 2714 * Calling hierarchical_reclaim is not enough because we should update 2715 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. 2716 * Moreover considering hierarchy, we should reclaim from the mem_over_limit, 2717 * not from the memcg which this page would be charged to. 2718 * try_charge_swapin does all of these works properly. 2719 */ 2720int mem_cgroup_shmem_charge_fallback(struct page *page, 2721 struct mm_struct *mm, 2722 gfp_t gfp_mask) 2723{ 2724 struct mem_cgroup *mem = NULL; 2725 int ret; 2726 2727 if (mem_cgroup_disabled()) 2728 return 0; 2729 2730 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); 2731 if (!ret) 2732 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */ 2733 2734 return ret; 2735} 2736 2737static DEFINE_MUTEX(set_limit_mutex); 2738 2739static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, 2740 unsigned long long val) 2741{ 2742 int retry_count; 2743 u64 memswlimit, memlimit; 2744 int ret = 0; 2745 int children = mem_cgroup_count_children(memcg); 2746 u64 curusage, oldusage; 2747 int enlarge; 2748 2749 /* 2750 * For keeping hierarchical_reclaim simple, how long we should retry 2751 * is depends on callers. We set our retry-count to be function 2752 * of # of children which we should visit in this loop. 2753 */ 2754 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; 2755 2756 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); 2757 2758 enlarge = 0; 2759 while (retry_count) { 2760 if (signal_pending(current)) { 2761 ret = -EINTR; 2762 break; 2763 } 2764 /* 2765 * Rather than hide all in some function, I do this in 2766 * open coded manner. You see what this really does. 2767 * We have to guarantee mem->res.limit < mem->memsw.limit. 2768 */ 2769 mutex_lock(&set_limit_mutex); 2770 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 2771 if (memswlimit < val) { 2772 ret = -EINVAL; 2773 mutex_unlock(&set_limit_mutex); 2774 break; 2775 } 2776 2777 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 2778 if (memlimit < val) 2779 enlarge = 1; 2780 2781 ret = res_counter_set_limit(&memcg->res, val); 2782 if (!ret) { 2783 if (memswlimit == val) 2784 memcg->memsw_is_minimum = true; 2785 else 2786 memcg->memsw_is_minimum = false; 2787 } 2788 mutex_unlock(&set_limit_mutex); 2789 2790 if (!ret) 2791 break; 2792 2793 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 2794 MEM_CGROUP_RECLAIM_SHRINK); 2795 curusage = res_counter_read_u64(&memcg->res, RES_USAGE); 2796 /* Usage is reduced ? */ 2797 if (curusage >= oldusage) 2798 retry_count--; 2799 else 2800 oldusage = curusage; 2801 } 2802 if (!ret && enlarge) 2803 memcg_oom_recover(memcg); 2804 2805 return ret; 2806} 2807 2808static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, 2809 unsigned long long val) 2810{ 2811 int retry_count; 2812 u64 memlimit, memswlimit, oldusage, curusage; 2813 int children = mem_cgroup_count_children(memcg); 2814 int ret = -EBUSY; 2815 int enlarge = 0; 2816 2817 /* see mem_cgroup_resize_res_limit */ 2818 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; 2819 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 2820 while (retry_count) { 2821 if (signal_pending(current)) { 2822 ret = -EINTR; 2823 break; 2824 } 2825 /* 2826 * Rather than hide all in some function, I do this in 2827 * open coded manner. You see what this really does. 2828 * We have to guarantee mem->res.limit < mem->memsw.limit. 2829 */ 2830 mutex_lock(&set_limit_mutex); 2831 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 2832 if (memlimit > val) { 2833 ret = -EINVAL; 2834 mutex_unlock(&set_limit_mutex); 2835 break; 2836 } 2837 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 2838 if (memswlimit < val) 2839 enlarge = 1; 2840 ret = res_counter_set_limit(&memcg->memsw, val); 2841 if (!ret) { 2842 if (memlimit == val) 2843 memcg->memsw_is_minimum = true; 2844 else 2845 memcg->memsw_is_minimum = false; 2846 } 2847 mutex_unlock(&set_limit_mutex); 2848 2849 if (!ret) 2850 break; 2851 2852 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 2853 MEM_CGROUP_RECLAIM_NOSWAP | 2854 MEM_CGROUP_RECLAIM_SHRINK); 2855 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 2856 /* Usage is reduced ? */ 2857 if (curusage >= oldusage) 2858 retry_count--; 2859 else 2860 oldusage = curusage; 2861 } 2862 if (!ret && enlarge) 2863 memcg_oom_recover(memcg); 2864 return ret; 2865} 2866 2867unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 2868 gfp_t gfp_mask, int nid, 2869 int zid) 2870{ 2871 unsigned long nr_reclaimed = 0; 2872 struct mem_cgroup_per_zone *mz, *next_mz = NULL; 2873 unsigned long reclaimed; 2874 int loop = 0; 2875 struct mem_cgroup_tree_per_zone *mctz; 2876 unsigned long long excess; 2877 2878 if (order > 0) 2879 return 0; 2880 2881 mctz = soft_limit_tree_node_zone(nid, zid); 2882 /* 2883 * This loop can run a while, specially if mem_cgroup's continuously 2884 * keep exceeding their soft limit and putting the system under 2885 * pressure 2886 */ 2887 do { 2888 if (next_mz) 2889 mz = next_mz; 2890 else 2891 mz = mem_cgroup_largest_soft_limit_node(mctz); 2892 if (!mz) 2893 break; 2894 2895 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone, 2896 gfp_mask, 2897 MEM_CGROUP_RECLAIM_SOFT); 2898 nr_reclaimed += reclaimed; 2899 spin_lock(&mctz->lock); 2900 2901 /* 2902 * If we failed to reclaim anything from this memory cgroup 2903 * it is time to move on to the next cgroup 2904 */ 2905 next_mz = NULL; 2906 if (!reclaimed) { 2907 do { 2908 /* 2909 * Loop until we find yet another one. 2910 * 2911 * By the time we get the soft_limit lock 2912 * again, someone might have aded the 2913 * group back on the RB tree. Iterate to 2914 * make sure we get a different mem. 2915 * mem_cgroup_largest_soft_limit_node returns 2916 * NULL if no other cgroup is present on 2917 * the tree 2918 */ 2919 next_mz = 2920 __mem_cgroup_largest_soft_limit_node(mctz); 2921 if (next_mz == mz) { 2922 css_put(&next_mz->mem->css); 2923 next_mz = NULL; 2924 } else /* next_mz == NULL or other memcg */ 2925 break; 2926 } while (1); 2927 } 2928 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 2929 excess = res_counter_soft_limit_excess(&mz->mem->res); 2930 /* 2931 * One school of thought says that we should not add 2932 * back the node to the tree if reclaim returns 0. 2933 * But our reclaim could return 0, simply because due 2934 * to priority we are exposing a smaller subset of 2935 * memory to reclaim from. Consider this as a longer 2936 * term TODO. 2937 */ 2938 /* If excess == 0, no tree ops */ 2939 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess); 2940 spin_unlock(&mctz->lock); 2941 css_put(&mz->mem->css); 2942 loop++; 2943 /* 2944 * Could not reclaim anything and there are no more 2945 * mem cgroups to try or we seem to be looping without 2946 * reclaiming anything. 2947 */ 2948 if (!nr_reclaimed && 2949 (next_mz == NULL || 2950 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) 2951 break; 2952 } while (!nr_reclaimed); 2953 if (next_mz) 2954 css_put(&next_mz->mem->css); 2955 return nr_reclaimed; 2956} 2957 2958/* 2959 * This routine traverse page_cgroup in given list and drop them all. 2960 * *And* this routine doesn't reclaim page itself, just removes page_cgroup. 2961 */ 2962static int mem_cgroup_force_empty_list(struct mem_cgroup *mem, 2963 int node, int zid, enum lru_list lru) 2964{ 2965 struct zone *zone; 2966 struct mem_cgroup_per_zone *mz; 2967 struct page_cgroup *pc, *busy; 2968 unsigned long flags, loop; 2969 struct list_head *list; 2970 int ret = 0; 2971 2972 zone = &NODE_DATA(node)->node_zones[zid]; 2973 mz = mem_cgroup_zoneinfo(mem, node, zid); 2974 list = &mz->lists[lru]; 2975 2976 loop = MEM_CGROUP_ZSTAT(mz, lru); 2977 /* give some margin against EBUSY etc...*/ 2978 loop += 256; 2979 busy = NULL; 2980 while (loop--) { 2981 ret = 0; 2982 spin_lock_irqsave(&zone->lru_lock, flags); 2983 if (list_empty(list)) { 2984 spin_unlock_irqrestore(&zone->lru_lock, flags); 2985 break; 2986 } 2987 pc = list_entry(list->prev, struct page_cgroup, lru); 2988 if (busy == pc) { 2989 list_move(&pc->lru, list); 2990 busy = NULL; 2991 spin_unlock_irqrestore(&zone->lru_lock, flags); 2992 continue; 2993 } 2994 spin_unlock_irqrestore(&zone->lru_lock, flags); 2995 2996 ret = mem_cgroup_move_parent(pc, mem, GFP_KERNEL); 2997 if (ret == -ENOMEM) 2998 break; 2999 3000 if (ret == -EBUSY || ret == -EINVAL) { 3001 /* found lock contention or "pc" is obsolete. */ 3002 busy = pc; 3003 cond_resched(); 3004 } else 3005 busy = NULL; 3006 } 3007 3008 if (!ret && !list_empty(list)) 3009 return -EBUSY; 3010 return ret; 3011} 3012 3013/* 3014 * make mem_cgroup's charge to be 0 if there is no task. 3015 * This enables deleting this mem_cgroup. 3016 */ 3017static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all) 3018{ 3019 int ret; 3020 int node, zid, shrink; 3021 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 3022 struct cgroup *cgrp = mem->css.cgroup; 3023 3024 css_get(&mem->css); 3025 3026 shrink = 0; 3027 /* should free all ? */ 3028 if (free_all) 3029 goto try_to_free; 3030move_account: 3031 do { 3032 ret = -EBUSY; 3033 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) 3034 goto out; 3035 ret = -EINTR; 3036 if (signal_pending(current)) 3037 goto out; 3038 /* This is for making all *used* pages to be on LRU. */ 3039 lru_add_drain_all(); 3040 drain_all_stock_sync(); 3041 ret = 0; 3042 for_each_node_state(node, N_HIGH_MEMORY) { 3043 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { 3044 enum lru_list l; 3045 for_each_lru(l) { 3046 ret = mem_cgroup_force_empty_list(mem, 3047 node, zid, l); 3048 if (ret) 3049 break; 3050 } 3051 } 3052 if (ret) 3053 break; 3054 } 3055 memcg_oom_recover(mem); 3056 /* it seems parent cgroup doesn't have enough mem */ 3057 if (ret == -ENOMEM) 3058 goto try_to_free; 3059 cond_resched(); 3060 /* "ret" should also be checked to ensure all lists are empty. */ 3061 } while (mem->res.usage > 0 || ret); 3062out: 3063 css_put(&mem->css); 3064 return ret; 3065 3066try_to_free: 3067 /* returns EBUSY if there is a task or if we come here twice. */ 3068 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { 3069 ret = -EBUSY; 3070 goto out; 3071 } 3072 /* we call try-to-free pages for make this cgroup empty */ 3073 lru_add_drain_all(); 3074 /* try to free all pages in this cgroup */ 3075 shrink = 1; 3076 while (nr_retries && mem->res.usage > 0) { 3077 int progress; 3078 3079 if (signal_pending(current)) { 3080 ret = -EINTR; 3081 goto out; 3082 } 3083 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, 3084 false, get_swappiness(mem)); 3085 if (!progress) { 3086 nr_retries--; 3087 /* maybe some writeback is necessary */ 3088 congestion_wait(BLK_RW_ASYNC, HZ/10); 3089 } 3090 3091 } 3092 lru_add_drain(); 3093 /* try move_account...there may be some *locked* pages. */ 3094 goto move_account; 3095} 3096 3097int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) 3098{ 3099 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); 3100} 3101 3102 3103static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) 3104{ 3105 return mem_cgroup_from_cont(cont)->use_hierarchy; 3106} 3107 3108static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, 3109 u64 val) 3110{ 3111 int retval = 0; 3112 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 3113 struct cgroup *parent = cont->parent; 3114 struct mem_cgroup *parent_mem = NULL; 3115 3116 if (parent) 3117 parent_mem = mem_cgroup_from_cont(parent); 3118 3119 cgroup_lock(); 3120 /* 3121 * If parent's use_hierarchy is set, we can't make any modifications 3122 * in the child subtrees. If it is unset, then the change can 3123 * occur, provided the current cgroup has no children. 3124 * 3125 * For the root cgroup, parent_mem is NULL, we allow value to be 3126 * set if there are no children. 3127 */ 3128 if ((!parent_mem || !parent_mem->use_hierarchy) && 3129 (val == 1 || val == 0)) { 3130 if (list_empty(&cont->children)) 3131 mem->use_hierarchy = val; 3132 else 3133 retval = -EBUSY; 3134 } else 3135 retval = -EINVAL; 3136 cgroup_unlock(); 3137 3138 return retval; 3139} 3140 3141struct mem_cgroup_idx_data { 3142 s64 val; 3143 enum mem_cgroup_stat_index idx; 3144}; 3145 3146static int 3147mem_cgroup_get_idx_stat(struct mem_cgroup *mem, void *data) 3148{ 3149 struct mem_cgroup_idx_data *d = data; 3150 d->val += mem_cgroup_read_stat(mem, d->idx); 3151 return 0; 3152} 3153 3154static void 3155mem_cgroup_get_recursive_idx_stat(struct mem_cgroup *mem, 3156 enum mem_cgroup_stat_index idx, s64 *val) 3157{ 3158 struct mem_cgroup_idx_data d; 3159 d.idx = idx; 3160 d.val = 0; 3161 mem_cgroup_walk_tree(mem, &d, mem_cgroup_get_idx_stat); 3162 *val = d.val; 3163} 3164 3165static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap) 3166{ 3167 u64 idx_val, val; 3168 3169 if (!mem_cgroup_is_root(mem)) { 3170 if (!swap) 3171 return res_counter_read_u64(&mem->res, RES_USAGE); 3172 else 3173 return res_counter_read_u64(&mem->memsw, RES_USAGE); 3174 } 3175 3176 mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_CACHE, &idx_val); 3177 val = idx_val; 3178 mem_cgroup_get_recursive_idx_stat(mem, MEM_CGROUP_STAT_RSS, &idx_val); 3179 val += idx_val; 3180 3181 if (swap) { 3182 mem_cgroup_get_recursive_idx_stat(mem, 3183 MEM_CGROUP_STAT_SWAPOUT, &idx_val); 3184 val += idx_val; 3185 } 3186 3187 return val << PAGE_SHIFT; 3188} 3189 3190static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 3191{ 3192 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 3193 u64 val; 3194 int type, name; 3195 3196 type = MEMFILE_TYPE(cft->private); 3197 name = MEMFILE_ATTR(cft->private); 3198 switch (type) { 3199 case _MEM: 3200 if (name == RES_USAGE) 3201 val = mem_cgroup_usage(mem, false); 3202 else 3203 val = res_counter_read_u64(&mem->res, name); 3204 break; 3205 case _MEMSWAP: 3206 if (name == RES_USAGE) 3207 val = mem_cgroup_usage(mem, true); 3208 else 3209 val = res_counter_read_u64(&mem->memsw, name); 3210 break; 3211 default: 3212 BUG(); 3213 break; 3214 } 3215 return val; 3216} 3217/* 3218 * The user of this function is... 3219 * RES_LIMIT. 3220 */ 3221static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 3222 const char *buffer) 3223{ 3224 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 3225 int type, name; 3226 unsigned long long val; 3227 int ret; 3228 3229 type = MEMFILE_TYPE(cft->private); 3230 name = MEMFILE_ATTR(cft->private); 3231 switch (name) { 3232 case RES_LIMIT: 3233 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ 3234 ret = -EINVAL; 3235 break; 3236 } 3237 /* This function does all necessary parse...reuse it */ 3238 ret = res_counter_memparse_write_strategy(buffer, &val); 3239 if (ret) 3240 break; 3241 if (type == _MEM) 3242 ret = mem_cgroup_resize_limit(memcg, val); 3243 else 3244 ret = mem_cgroup_resize_memsw_limit(memcg, val); 3245 break; 3246 case RES_SOFT_LIMIT: 3247 ret = res_counter_memparse_write_strategy(buffer, &val); 3248 if (ret) 3249 break; 3250 /* 3251 * For memsw, soft limits are hard to implement in terms 3252 * of semantics, for now, we support soft limits for 3253 * control without swap 3254 */ 3255 if (type == _MEM) 3256 ret = res_counter_set_soft_limit(&memcg->res, val); 3257 else 3258 ret = -EINVAL; 3259 break; 3260 default: 3261 ret = -EINVAL; /* should be BUG() ? */ 3262 break; 3263 } 3264 return ret; 3265} 3266 3267static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 3268 unsigned long long *mem_limit, unsigned long long *memsw_limit) 3269{ 3270 struct cgroup *cgroup; 3271 unsigned long long min_limit, min_memsw_limit, tmp; 3272 3273 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3274 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3275 cgroup = memcg->css.cgroup; 3276 if (!memcg->use_hierarchy) 3277 goto out; 3278 3279 while (cgroup->parent) { 3280 cgroup = cgroup->parent; 3281 memcg = mem_cgroup_from_cont(cgroup); 3282 if (!memcg->use_hierarchy) 3283 break; 3284 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); 3285 min_limit = min(min_limit, tmp); 3286 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3287 min_memsw_limit = min(min_memsw_limit, tmp); 3288 } 3289out: 3290 *mem_limit = min_limit; 3291 *memsw_limit = min_memsw_limit; 3292 return; 3293} 3294 3295static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) 3296{ 3297 struct mem_cgroup *mem; 3298 int type, name; 3299 3300 mem = mem_cgroup_from_cont(cont); 3301 type = MEMFILE_TYPE(event); 3302 name = MEMFILE_ATTR(event); 3303 switch (name) { 3304 case RES_MAX_USAGE: 3305 if (type == _MEM) 3306 res_counter_reset_max(&mem->res); 3307 else 3308 res_counter_reset_max(&mem->memsw); 3309 break; 3310 case RES_FAILCNT: 3311 if (type == _MEM) 3312 res_counter_reset_failcnt(&mem->res); 3313 else 3314 res_counter_reset_failcnt(&mem->memsw); 3315 break; 3316 } 3317 3318 return 0; 3319} 3320 3321static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, 3322 struct cftype *cft) 3323{ 3324 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; 3325} 3326 3327#ifdef CONFIG_MMU 3328static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 3329 struct cftype *cft, u64 val) 3330{ 3331 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 3332 3333 if (val >= (1 << NR_MOVE_TYPE)) 3334 return -EINVAL; 3335 /* 3336 * We check this value several times in both in can_attach() and 3337 * attach(), so we need cgroup lock to prevent this value from being 3338 * inconsistent. 3339 */ 3340 cgroup_lock(); 3341 mem->move_charge_at_immigrate = val; 3342 cgroup_unlock(); 3343 3344 return 0; 3345} 3346#else 3347static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 3348 struct cftype *cft, u64 val) 3349{ 3350 return -ENOSYS; 3351} 3352#endif 3353 3354 3355/* For read statistics */ 3356enum { 3357 MCS_CACHE, 3358 MCS_RSS, 3359 MCS_FILE_MAPPED, 3360 MCS_PGPGIN, 3361 MCS_PGPGOUT, 3362 MCS_SWAP, 3363 MCS_INACTIVE_ANON, 3364 MCS_ACTIVE_ANON, 3365 MCS_INACTIVE_FILE, 3366 MCS_ACTIVE_FILE, 3367 MCS_UNEVICTABLE, 3368 NR_MCS_STAT, 3369}; 3370 3371struct mcs_total_stat { 3372 s64 stat[NR_MCS_STAT]; 3373}; 3374 3375struct { 3376 char *local_name; 3377 char *total_name; 3378} memcg_stat_strings[NR_MCS_STAT] = { 3379 {"cache", "total_cache"}, 3380 {"rss", "total_rss"}, 3381 {"mapped_file", "total_mapped_file"}, 3382 {"pgpgin", "total_pgpgin"}, 3383 {"pgpgout", "total_pgpgout"}, 3384 {"swap", "total_swap"}, 3385 {"inactive_anon", "total_inactive_anon"}, 3386 {"active_anon", "total_active_anon"}, 3387 {"inactive_file", "total_inactive_file"}, 3388 {"active_file", "total_active_file"}, 3389 {"unevictable", "total_unevictable"} 3390}; 3391 3392 3393static int mem_cgroup_get_local_stat(struct mem_cgroup *mem, void *data) 3394{ 3395 struct mcs_total_stat *s = data; 3396 s64 val; 3397 3398 /* per cpu stat */ 3399 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); 3400 s->stat[MCS_CACHE] += val * PAGE_SIZE; 3401 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); 3402 s->stat[MCS_RSS] += val * PAGE_SIZE; 3403 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED); 3404 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; 3405 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGIN_COUNT); 3406 s->stat[MCS_PGPGIN] += val; 3407 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_PGPGOUT_COUNT); 3408 s->stat[MCS_PGPGOUT] += val; 3409 if (do_swap_account) { 3410 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT); 3411 s->stat[MCS_SWAP] += val * PAGE_SIZE; 3412 } 3413 3414 /* per zone stat */ 3415 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); 3416 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; 3417 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); 3418 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; 3419 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); 3420 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; 3421 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); 3422 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; 3423 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); 3424 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; 3425 return 0; 3426} 3427 3428static void 3429mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) 3430{ 3431 mem_cgroup_walk_tree(mem, s, mem_cgroup_get_local_stat); 3432} 3433 3434static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 3435 struct cgroup_map_cb *cb) 3436{ 3437 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 3438 struct mcs_total_stat mystat; 3439 int i; 3440 3441 memset(&mystat, 0, sizeof(mystat)); 3442 mem_cgroup_get_local_stat(mem_cont, &mystat); 3443 3444 for (i = 0; i < NR_MCS_STAT; i++) { 3445 if (i == MCS_SWAP && !do_swap_account) 3446 continue; 3447 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); 3448 } 3449 3450 /* Hierarchical information */ 3451 { 3452 unsigned long long limit, memsw_limit; 3453 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); 3454 cb->fill(cb, "hierarchical_memory_limit", limit); 3455 if (do_swap_account) 3456 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); 3457 } 3458 3459 memset(&mystat, 0, sizeof(mystat)); 3460 mem_cgroup_get_total_stat(mem_cont, &mystat); 3461 for (i = 0; i < NR_MCS_STAT; i++) { 3462 if (i == MCS_SWAP && !do_swap_account) 3463 continue; 3464 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); 3465 } 3466 3467#ifdef CONFIG_DEBUG_VM 3468 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); 3469 3470 { 3471 int nid, zid; 3472 struct mem_cgroup_per_zone *mz; 3473 unsigned long recent_rotated[2] = {0, 0}; 3474 unsigned long recent_scanned[2] = {0, 0}; 3475 3476 for_each_online_node(nid) 3477 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 3478 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 3479 3480 recent_rotated[0] += 3481 mz->reclaim_stat.recent_rotated[0]; 3482 recent_rotated[1] += 3483 mz->reclaim_stat.recent_rotated[1]; 3484 recent_scanned[0] += 3485 mz->reclaim_stat.recent_scanned[0]; 3486 recent_scanned[1] += 3487 mz->reclaim_stat.recent_scanned[1]; 3488 } 3489 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); 3490 cb->fill(cb, "recent_rotated_file", recent_rotated[1]); 3491 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); 3492 cb->fill(cb, "recent_scanned_file", recent_scanned[1]); 3493 } 3494#endif 3495 3496 return 0; 3497} 3498 3499static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) 3500{ 3501 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3502 3503 return get_swappiness(memcg); 3504} 3505 3506static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, 3507 u64 val) 3508{ 3509 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3510 struct mem_cgroup *parent; 3511 3512 if (val > 100) 3513 return -EINVAL; 3514 3515 if (cgrp->parent == NULL) 3516 return -EINVAL; 3517 3518 parent = mem_cgroup_from_cont(cgrp->parent); 3519 3520 cgroup_lock(); 3521 3522 /* If under hierarchy, only empty-root can set this value */ 3523 if ((parent->use_hierarchy) || 3524 (memcg->use_hierarchy && !list_empty(&cgrp->children))) { 3525 cgroup_unlock(); 3526 return -EINVAL; 3527 } 3528 3529 spin_lock(&memcg->reclaim_param_lock); 3530 memcg->swappiness = val; 3531 spin_unlock(&memcg->reclaim_param_lock); 3532 3533 cgroup_unlock(); 3534 3535 return 0; 3536} 3537 3538static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) 3539{ 3540 struct mem_cgroup_threshold_ary *t; 3541 u64 usage; 3542 int i; 3543 3544 rcu_read_lock(); 3545 if (!swap) 3546 t = rcu_dereference(memcg->thresholds.primary); 3547 else 3548 t = rcu_dereference(memcg->memsw_thresholds.primary); 3549 3550 if (!t) 3551 goto unlock; 3552 3553 usage = mem_cgroup_usage(memcg, swap); 3554 3555 /* 3556 * current_threshold points to threshold just below usage. 3557 * If it's not true, a threshold was crossed after last 3558 * call of __mem_cgroup_threshold(). 3559 */ 3560 i = t->current_threshold; 3561 3562 /* 3563 * Iterate backward over array of thresholds starting from 3564 * current_threshold and check if a threshold is crossed. 3565 * If none of thresholds below usage is crossed, we read 3566 * only one element of the array here. 3567 */ 3568 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) 3569 eventfd_signal(t->entries[i].eventfd, 1); 3570 3571 /* i = current_threshold + 1 */ 3572 i++; 3573 3574 /* 3575 * Iterate forward over array of thresholds starting from 3576 * current_threshold+1 and check if a threshold is crossed. 3577 * If none of thresholds above usage is crossed, we read 3578 * only one element of the array here. 3579 */ 3580 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) 3581 eventfd_signal(t->entries[i].eventfd, 1); 3582 3583 /* Update current_threshold */ 3584 t->current_threshold = i - 1; 3585unlock: 3586 rcu_read_unlock(); 3587} 3588 3589static void mem_cgroup_threshold(struct mem_cgroup *memcg) 3590{ 3591 __mem_cgroup_threshold(memcg, false); 3592 if (do_swap_account) 3593 __mem_cgroup_threshold(memcg, true); 3594} 3595 3596static int compare_thresholds(const void *a, const void *b) 3597{ 3598 const struct mem_cgroup_threshold *_a = a; 3599 const struct mem_cgroup_threshold *_b = b; 3600 3601 return _a->threshold - _b->threshold; 3602} 3603 3604static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem, void *data) 3605{ 3606 struct mem_cgroup_eventfd_list *ev; 3607 3608 list_for_each_entry(ev, &mem->oom_notify, list) 3609 eventfd_signal(ev->eventfd, 1); 3610 return 0; 3611} 3612 3613static void mem_cgroup_oom_notify(struct mem_cgroup *mem) 3614{ 3615 mem_cgroup_walk_tree(mem, NULL, mem_cgroup_oom_notify_cb); 3616} 3617 3618static int mem_cgroup_usage_register_event(struct cgroup *cgrp, 3619 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 3620{ 3621 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3622 struct mem_cgroup_thresholds *thresholds; 3623 struct mem_cgroup_threshold_ary *new; 3624 int type = MEMFILE_TYPE(cft->private); 3625 u64 threshold, usage; 3626 int i, size, ret; 3627 3628 ret = res_counter_memparse_write_strategy(args, &threshold); 3629 if (ret) 3630 return ret; 3631 3632 mutex_lock(&memcg->thresholds_lock); 3633 3634 if (type == _MEM) 3635 thresholds = &memcg->thresholds; 3636 else if (type == _MEMSWAP) 3637 thresholds = &memcg->memsw_thresholds; 3638 else 3639 BUG(); 3640 3641 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 3642 3643 /* Check if a threshold crossed before adding a new one */ 3644 if (thresholds->primary) 3645 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 3646 3647 size = thresholds->primary ? thresholds->primary->size + 1 : 1; 3648 3649 /* Allocate memory for new array of thresholds */ 3650 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), 3651 GFP_KERNEL); 3652 if (!new) { 3653 ret = -ENOMEM; 3654 goto unlock; 3655 } 3656 new->size = size; 3657 3658 /* Copy thresholds (if any) to new array */ 3659 if (thresholds->primary) { 3660 memcpy(new->entries, thresholds->primary->entries, (size - 1) * 3661 sizeof(struct mem_cgroup_threshold)); 3662 } 3663 3664 /* Add new threshold */ 3665 new->entries[size - 1].eventfd = eventfd; 3666 new->entries[size - 1].threshold = threshold; 3667 3668 /* Sort thresholds. Registering of new threshold isn't time-critical */ 3669 sort(new->entries, size, sizeof(struct mem_cgroup_threshold), 3670 compare_thresholds, NULL); 3671 3672 /* Find current threshold */ 3673 new->current_threshold = -1; 3674 for (i = 0; i < size; i++) { 3675 if (new->entries[i].threshold < usage) { 3676 /* 3677 * new->current_threshold will not be used until 3678 * rcu_assign_pointer(), so it's safe to increment 3679 * it here. 3680 */ 3681 ++new->current_threshold; 3682 } 3683 } 3684 3685 /* Free old spare buffer and save old primary buffer as spare */ 3686 kfree(thresholds->spare); 3687 thresholds->spare = thresholds->primary; 3688 3689 rcu_assign_pointer(thresholds->primary, new); 3690 3691 /* To be sure that nobody uses thresholds */ 3692 synchronize_rcu(); 3693 3694unlock: 3695 mutex_unlock(&memcg->thresholds_lock); 3696 3697 return ret; 3698} 3699 3700static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, 3701 struct cftype *cft, struct eventfd_ctx *eventfd) 3702{ 3703 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3704 struct mem_cgroup_thresholds *thresholds; 3705 struct mem_cgroup_threshold_ary *new; 3706 int type = MEMFILE_TYPE(cft->private); 3707 u64 usage; 3708 int i, j, size; 3709 3710 mutex_lock(&memcg->thresholds_lock); 3711 if (type == _MEM) 3712 thresholds = &memcg->thresholds; 3713 else if (type == _MEMSWAP) 3714 thresholds = &memcg->memsw_thresholds; 3715 else 3716 BUG(); 3717 3718 /* 3719 * Something went wrong if we trying to unregister a threshold 3720 * if we don't have thresholds 3721 */ 3722 BUG_ON(!thresholds); 3723 3724 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 3725 3726 /* Check if a threshold crossed before removing */ 3727 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 3728 3729 /* Calculate new number of threshold */ 3730 size = 0; 3731 for (i = 0; i < thresholds->primary->size; i++) { 3732 if (thresholds->primary->entries[i].eventfd != eventfd) 3733 size++; 3734 } 3735 3736 new = thresholds->spare; 3737 3738 /* Set thresholds array to NULL if we don't have thresholds */ 3739 if (!size) { 3740 kfree(new); 3741 new = NULL; 3742 goto swap_buffers; 3743 } 3744 3745 new->size = size; 3746 3747 /* Copy thresholds and find current threshold */ 3748 new->current_threshold = -1; 3749 for (i = 0, j = 0; i < thresholds->primary->size; i++) { 3750 if (thresholds->primary->entries[i].eventfd == eventfd) 3751 continue; 3752 3753 new->entries[j] = thresholds->primary->entries[i]; 3754 if (new->entries[j].threshold < usage) { 3755 /* 3756 * new->current_threshold will not be used 3757 * until rcu_assign_pointer(), so it's safe to increment 3758 * it here. 3759 */ 3760 ++new->current_threshold; 3761 } 3762 j++; 3763 } 3764 3765swap_buffers: 3766 /* Swap primary and spare array */ 3767 thresholds->spare = thresholds->primary; 3768 rcu_assign_pointer(thresholds->primary, new); 3769 3770 /* To be sure that nobody uses thresholds */ 3771 synchronize_rcu(); 3772 3773 mutex_unlock(&memcg->thresholds_lock); 3774} 3775 3776static int mem_cgroup_oom_register_event(struct cgroup *cgrp, 3777 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 3778{ 3779 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3780 struct mem_cgroup_eventfd_list *event; 3781 int type = MEMFILE_TYPE(cft->private); 3782 3783 BUG_ON(type != _OOM_TYPE); 3784 event = kmalloc(sizeof(*event), GFP_KERNEL); 3785 if (!event) 3786 return -ENOMEM; 3787 3788 mutex_lock(&memcg_oom_mutex); 3789 3790 event->eventfd = eventfd; 3791 list_add(&event->list, &memcg->oom_notify); 3792 3793 /* already in OOM ? */ 3794 if (atomic_read(&memcg->oom_lock)) 3795 eventfd_signal(eventfd, 1); 3796 mutex_unlock(&memcg_oom_mutex); 3797 3798 return 0; 3799} 3800 3801static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, 3802 struct cftype *cft, struct eventfd_ctx *eventfd) 3803{ 3804 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 3805 struct mem_cgroup_eventfd_list *ev, *tmp; 3806 int type = MEMFILE_TYPE(cft->private); 3807 3808 BUG_ON(type != _OOM_TYPE); 3809 3810 mutex_lock(&memcg_oom_mutex); 3811 3812 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) { 3813 if (ev->eventfd == eventfd) { 3814 list_del(&ev->list); 3815 kfree(ev); 3816 } 3817 } 3818 3819 mutex_unlock(&memcg_oom_mutex); 3820} 3821 3822static int mem_cgroup_oom_control_read(struct cgroup *cgrp, 3823 struct cftype *cft, struct cgroup_map_cb *cb) 3824{ 3825 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 3826 3827 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable); 3828 3829 if (atomic_read(&mem->oom_lock)) 3830 cb->fill(cb, "under_oom", 1); 3831 else 3832 cb->fill(cb, "under_oom", 0); 3833 return 0; 3834} 3835 3836static int mem_cgroup_oom_control_write(struct cgroup *cgrp, 3837 struct cftype *cft, u64 val) 3838{ 3839 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 3840 struct mem_cgroup *parent; 3841 3842 /* cannot set to root cgroup and only 0 and 1 are allowed */ 3843 if (!cgrp->parent || !((val == 0) || (val == 1))) 3844 return -EINVAL; 3845 3846 parent = mem_cgroup_from_cont(cgrp->parent); 3847 3848 cgroup_lock(); 3849 /* oom-kill-disable is a flag for subhierarchy. */ 3850 if ((parent->use_hierarchy) || 3851 (mem->use_hierarchy && !list_empty(&cgrp->children))) { 3852 cgroup_unlock(); 3853 return -EINVAL; 3854 } 3855 mem->oom_kill_disable = val; 3856 if (!val) 3857 memcg_oom_recover(mem); 3858 cgroup_unlock(); 3859 return 0; 3860} 3861 3862static struct cftype mem_cgroup_files[] = { 3863 { 3864 .name = "usage_in_bytes", 3865 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), 3866 .read_u64 = mem_cgroup_read, 3867 .register_event = mem_cgroup_usage_register_event, 3868 .unregister_event = mem_cgroup_usage_unregister_event, 3869 }, 3870 { 3871 .name = "max_usage_in_bytes", 3872 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), 3873 .trigger = mem_cgroup_reset, 3874 .read_u64 = mem_cgroup_read, 3875 }, 3876 { 3877 .name = "limit_in_bytes", 3878 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), 3879 .write_string = mem_cgroup_write, 3880 .read_u64 = mem_cgroup_read, 3881 }, 3882 { 3883 .name = "soft_limit_in_bytes", 3884 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), 3885 .write_string = mem_cgroup_write, 3886 .read_u64 = mem_cgroup_read, 3887 }, 3888 { 3889 .name = "failcnt", 3890 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), 3891 .trigger = mem_cgroup_reset, 3892 .read_u64 = mem_cgroup_read, 3893 }, 3894 { 3895 .name = "stat", 3896 .read_map = mem_control_stat_show, 3897 }, 3898 { 3899 .name = "force_empty", 3900 .trigger = mem_cgroup_force_empty_write, 3901 }, 3902 { 3903 .name = "use_hierarchy", 3904 .write_u64 = mem_cgroup_hierarchy_write, 3905 .read_u64 = mem_cgroup_hierarchy_read, 3906 }, 3907 { 3908 .name = "swappiness", 3909 .read_u64 = mem_cgroup_swappiness_read, 3910 .write_u64 = mem_cgroup_swappiness_write, 3911 }, 3912 { 3913 .name = "move_charge_at_immigrate", 3914 .read_u64 = mem_cgroup_move_charge_read, 3915 .write_u64 = mem_cgroup_move_charge_write, 3916 }, 3917 { 3918 .name = "oom_control", 3919 .read_map = mem_cgroup_oom_control_read, 3920 .write_u64 = mem_cgroup_oom_control_write, 3921 .register_event = mem_cgroup_oom_register_event, 3922 .unregister_event = mem_cgroup_oom_unregister_event, 3923 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), 3924 }, 3925}; 3926 3927#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 3928static struct cftype memsw_cgroup_files[] = { 3929 { 3930 .name = "memsw.usage_in_bytes", 3931 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), 3932 .read_u64 = mem_cgroup_read, 3933 .register_event = mem_cgroup_usage_register_event, 3934 .unregister_event = mem_cgroup_usage_unregister_event, 3935 }, 3936 { 3937 .name = "memsw.max_usage_in_bytes", 3938 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), 3939 .trigger = mem_cgroup_reset, 3940 .read_u64 = mem_cgroup_read, 3941 }, 3942 { 3943 .name = "memsw.limit_in_bytes", 3944 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), 3945 .write_string = mem_cgroup_write, 3946 .read_u64 = mem_cgroup_read, 3947 }, 3948 { 3949 .name = "memsw.failcnt", 3950 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), 3951 .trigger = mem_cgroup_reset, 3952 .read_u64 = mem_cgroup_read, 3953 }, 3954}; 3955 3956static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 3957{ 3958 if (!do_swap_account) 3959 return 0; 3960 return cgroup_add_files(cont, ss, memsw_cgroup_files, 3961 ARRAY_SIZE(memsw_cgroup_files)); 3962}; 3963#else 3964static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 3965{ 3966 return 0; 3967} 3968#endif 3969 3970static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 3971{ 3972 struct mem_cgroup_per_node *pn; 3973 struct mem_cgroup_per_zone *mz; 3974 enum lru_list l; 3975 int zone, tmp = node; 3976 /* 3977 * This routine is called against possible nodes. 3978 * But it's BUG to call kmalloc() against offline node. 3979 * 3980 * TODO: this routine can waste much memory for nodes which will 3981 * never be onlined. It's better to use memory hotplug callback 3982 * function. 3983 */ 3984 if (!node_state(node, N_NORMAL_MEMORY)) 3985 tmp = -1; 3986 pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, tmp); 3987 if (!pn) 3988 return 1; 3989 3990 mem->info.nodeinfo[node] = pn; 3991 memset(pn, 0, sizeof(*pn)); 3992 3993 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 3994 mz = &pn->zoneinfo[zone]; 3995 for_each_lru(l) 3996 INIT_LIST_HEAD(&mz->lists[l]); 3997 mz->usage_in_excess = 0; 3998 mz->on_tree = false; 3999 mz->mem = mem; 4000 } 4001 return 0; 4002} 4003 4004static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 4005{ 4006 kfree(mem->info.nodeinfo[node]); 4007} 4008 4009static struct mem_cgroup *mem_cgroup_alloc(void) 4010{ 4011 struct mem_cgroup *mem; 4012 int size = sizeof(struct mem_cgroup); 4013 4014 /* Can be very big if MAX_NUMNODES is very big */ 4015 if (size < PAGE_SIZE) 4016 mem = kmalloc(size, GFP_KERNEL); 4017 else 4018 mem = vmalloc(size); 4019 4020 if (!mem) 4021 return NULL; 4022 4023 memset(mem, 0, size); 4024 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu); 4025 if (!mem->stat) { 4026 if (size < PAGE_SIZE) 4027 kfree(mem); 4028 else 4029 vfree(mem); 4030 mem = NULL; 4031 } 4032 return mem; 4033} 4034 4035/* 4036 * At destroying mem_cgroup, references from swap_cgroup can remain. 4037 * (scanning all at force_empty is too costly...) 4038 * 4039 * Instead of clearing all references at force_empty, we remember 4040 * the number of reference from swap_cgroup and free mem_cgroup when 4041 * it goes down to 0. 4042 * 4043 * Removal of cgroup itself succeeds regardless of refs from swap. 4044 */ 4045 4046static void __mem_cgroup_free(struct mem_cgroup *mem) 4047{ 4048 int node; 4049 4050 mem_cgroup_remove_from_trees(mem); 4051 free_css_id(&mem_cgroup_subsys, &mem->css); 4052 4053 for_each_node_state(node, N_POSSIBLE) 4054 free_mem_cgroup_per_zone_info(mem, node); 4055 4056 free_percpu(mem->stat); 4057 if (sizeof(struct mem_cgroup) < PAGE_SIZE) 4058 kfree(mem); 4059 else 4060 vfree(mem); 4061} 4062 4063static void mem_cgroup_get(struct mem_cgroup *mem) 4064{ 4065 atomic_inc(&mem->refcnt); 4066} 4067 4068static void __mem_cgroup_put(struct mem_cgroup *mem, int count) 4069{ 4070 if (atomic_sub_and_test(count, &mem->refcnt)) { 4071 struct mem_cgroup *parent = parent_mem_cgroup(mem); 4072 __mem_cgroup_free(mem); 4073 if (parent) 4074 mem_cgroup_put(parent); 4075 } 4076} 4077 4078static void mem_cgroup_put(struct mem_cgroup *mem) 4079{ 4080 __mem_cgroup_put(mem, 1); 4081} 4082 4083/* 4084 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. 4085 */ 4086static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) 4087{ 4088 if (!mem->res.parent) 4089 return NULL; 4090 return mem_cgroup_from_res_counter(mem->res.parent, res); 4091} 4092 4093#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4094static void __init enable_swap_cgroup(void) 4095{ 4096 if (!mem_cgroup_disabled() && really_do_swap_account) 4097 do_swap_account = 1; 4098} 4099#else 4100static void __init enable_swap_cgroup(void) 4101{ 4102} 4103#endif 4104 4105static int mem_cgroup_soft_limit_tree_init(void) 4106{ 4107 struct mem_cgroup_tree_per_node *rtpn; 4108 struct mem_cgroup_tree_per_zone *rtpz; 4109 int tmp, node, zone; 4110 4111 for_each_node_state(node, N_POSSIBLE) { 4112 tmp = node; 4113 if (!node_state(node, N_NORMAL_MEMORY)) 4114 tmp = -1; 4115 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); 4116 if (!rtpn) 4117 return 1; 4118 4119 soft_limit_tree.rb_tree_per_node[node] = rtpn; 4120 4121 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 4122 rtpz = &rtpn->rb_tree_per_zone[zone]; 4123 rtpz->rb_root = RB_ROOT; 4124 spin_lock_init(&rtpz->lock); 4125 } 4126 } 4127 return 0; 4128} 4129 4130static struct cgroup_subsys_state * __ref 4131mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 4132{ 4133 struct mem_cgroup *mem, *parent; 4134 long error = -ENOMEM; 4135 int node; 4136 4137 mem = mem_cgroup_alloc(); 4138 if (!mem) 4139 return ERR_PTR(error); 4140 4141 for_each_node_state(node, N_POSSIBLE) 4142 if (alloc_mem_cgroup_per_zone_info(mem, node)) 4143 goto free_out; 4144 4145 /* root ? */ 4146 if (cont->parent == NULL) { 4147 int cpu; 4148 enable_swap_cgroup(); 4149 parent = NULL; 4150 root_mem_cgroup = mem; 4151 if (mem_cgroup_soft_limit_tree_init()) 4152 goto free_out; 4153 for_each_possible_cpu(cpu) { 4154 struct memcg_stock_pcp *stock = 4155 &per_cpu(memcg_stock, cpu); 4156 INIT_WORK(&stock->work, drain_local_stock); 4157 } 4158 hotcpu_notifier(memcg_stock_cpu_callback, 0); 4159 } else { 4160 parent = mem_cgroup_from_cont(cont->parent); 4161 mem->use_hierarchy = parent->use_hierarchy; 4162 mem->oom_kill_disable = parent->oom_kill_disable; 4163 } 4164 4165 if (parent && parent->use_hierarchy) { 4166 res_counter_init(&mem->res, &parent->res); 4167 res_counter_init(&mem->memsw, &parent->memsw); 4168 /* 4169 * We increment refcnt of the parent to ensure that we can 4170 * safely access it on res_counter_charge/uncharge. 4171 * This refcnt will be decremented when freeing this 4172 * mem_cgroup(see mem_cgroup_put). 4173 */ 4174 mem_cgroup_get(parent); 4175 } else { 4176 res_counter_init(&mem->res, NULL); 4177 res_counter_init(&mem->memsw, NULL); 4178 } 4179 mem->last_scanned_child = 0; 4180 spin_lock_init(&mem->reclaim_param_lock); 4181 INIT_LIST_HEAD(&mem->oom_notify); 4182 4183 if (parent) 4184 mem->swappiness = get_swappiness(parent); 4185 atomic_set(&mem->refcnt, 1); 4186 mem->move_charge_at_immigrate = 0; 4187 mutex_init(&mem->thresholds_lock); 4188 return &mem->css; 4189free_out: 4190 __mem_cgroup_free(mem); 4191 root_mem_cgroup = NULL; 4192 return ERR_PTR(error); 4193} 4194 4195static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, 4196 struct cgroup *cont) 4197{ 4198 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 4199 4200 return mem_cgroup_force_empty(mem, false); 4201} 4202 4203static void mem_cgroup_destroy(struct cgroup_subsys *ss, 4204 struct cgroup *cont) 4205{ 4206 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 4207 4208 mem_cgroup_put(mem); 4209} 4210 4211static int mem_cgroup_populate(struct cgroup_subsys *ss, 4212 struct cgroup *cont) 4213{ 4214 int ret; 4215 4216 ret = cgroup_add_files(cont, ss, mem_cgroup_files, 4217 ARRAY_SIZE(mem_cgroup_files)); 4218 4219 if (!ret) 4220 ret = register_memsw_files(cont, ss); 4221 return ret; 4222} 4223 4224#ifdef CONFIG_MMU 4225/* Handlers for move charge at task migration. */ 4226#define PRECHARGE_COUNT_AT_ONCE 256 4227static int mem_cgroup_do_precharge(unsigned long count) 4228{ 4229 int ret = 0; 4230 int batch_count = PRECHARGE_COUNT_AT_ONCE; 4231 struct mem_cgroup *mem = mc.to; 4232 4233 if (mem_cgroup_is_root(mem)) { 4234 mc.precharge += count; 4235 /* we don't need css_get for root */ 4236 return ret; 4237 } 4238 /* try to charge at once */ 4239 if (count > 1) { 4240 struct res_counter *dummy; 4241 /* 4242 * "mem" cannot be under rmdir() because we've already checked 4243 * by cgroup_lock_live_cgroup() that it is not removed and we 4244 * are still under the same cgroup_mutex. So we can postpone 4245 * css_get(). 4246 */ 4247 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy)) 4248 goto one_by_one; 4249 if (do_swap_account && res_counter_charge(&mem->memsw, 4250 PAGE_SIZE * count, &dummy)) { 4251 res_counter_uncharge(&mem->res, PAGE_SIZE * count); 4252 goto one_by_one; 4253 } 4254 mc.precharge += count; 4255 return ret; 4256 } 4257one_by_one: 4258 /* fall back to one by one charge */ 4259 while (count--) { 4260 if (signal_pending(current)) { 4261 ret = -EINTR; 4262 break; 4263 } 4264 if (!batch_count--) { 4265 batch_count = PRECHARGE_COUNT_AT_ONCE; 4266 cond_resched(); 4267 } 4268 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, &mem, false); 4269 if (ret || !mem) 4270 /* mem_cgroup_clear_mc() will do uncharge later */ 4271 return -ENOMEM; 4272 mc.precharge++; 4273 } 4274 return ret; 4275} 4276 4277/** 4278 * is_target_pte_for_mc - check a pte whether it is valid for move charge 4279 * @vma: the vma the pte to be checked belongs 4280 * @addr: the address corresponding to the pte to be checked 4281 * @ptent: the pte to be checked 4282 * @target: the pointer the target page or swap ent will be stored(can be NULL) 4283 * 4284 * Returns 4285 * 0(MC_TARGET_NONE): if the pte is not a target for move charge. 4286 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for 4287 * move charge. if @target is not NULL, the page is stored in target->page 4288 * with extra refcnt got(Callers should handle it). 4289 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a 4290 * target for charge migration. if @target is not NULL, the entry is stored 4291 * in target->ent. 4292 * 4293 * Called with pte lock held. 4294 */ 4295union mc_target { 4296 struct page *page; 4297 swp_entry_t ent; 4298}; 4299 4300enum mc_target_type { 4301 MC_TARGET_NONE, /* not used */ 4302 MC_TARGET_PAGE, 4303 MC_TARGET_SWAP, 4304}; 4305 4306static struct page *mc_handle_present_pte(struct vm_area_struct *vma, 4307 unsigned long addr, pte_t ptent) 4308{ 4309 struct page *page = vm_normal_page(vma, addr, ptent); 4310 4311 if (!page || !page_mapped(page)) 4312 return NULL; 4313 if (PageAnon(page)) { 4314 /* we don't move shared anon */ 4315 if (!move_anon() || page_mapcount(page) > 2) 4316 return NULL; 4317 } else if (!move_file()) 4318 /* we ignore mapcount for file pages */ 4319 return NULL; 4320 if (!get_page_unless_zero(page)) 4321 return NULL; 4322 4323 return page; 4324} 4325 4326static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, 4327 unsigned long addr, pte_t ptent, swp_entry_t *entry) 4328{ 4329 int usage_count; 4330 struct page *page = NULL; 4331 swp_entry_t ent = pte_to_swp_entry(ptent); 4332 4333 if (!move_anon() || non_swap_entry(ent)) 4334 return NULL; 4335 usage_count = mem_cgroup_count_swap_user(ent, &page); 4336 if (usage_count > 1) { /* we don't move shared anon */ 4337 if (page) 4338 put_page(page); 4339 return NULL; 4340 } 4341 if (do_swap_account) 4342 entry->val = ent.val; 4343 4344 return page; 4345} 4346 4347static struct page *mc_handle_file_pte(struct vm_area_struct *vma, 4348 unsigned long addr, pte_t ptent, swp_entry_t *entry) 4349{ 4350 struct page *page = NULL; 4351 struct inode *inode; 4352 struct address_space *mapping; 4353 pgoff_t pgoff; 4354 4355 if (!vma->vm_file) /* anonymous vma */ 4356 return NULL; 4357 if (!move_file()) 4358 return NULL; 4359 4360 inode = vma->vm_file->f_path.dentry->d_inode; 4361 mapping = vma->vm_file->f_mapping; 4362 if (pte_none(ptent)) 4363 pgoff = linear_page_index(vma, addr); 4364 else /* pte_file(ptent) is true */ 4365 pgoff = pte_to_pgoff(ptent); 4366 4367 /* page is moved even if it's not RSS of this task(page-faulted). */ 4368 if (!mapping_cap_swap_backed(mapping)) { /* normal file */ 4369 page = find_get_page(mapping, pgoff); 4370 } else { /* shmem/tmpfs file. we should take account of swap too. */ 4371 swp_entry_t ent; 4372 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent); 4373 if (do_swap_account) 4374 entry->val = ent.val; 4375 } 4376 4377 return page; 4378} 4379 4380static int is_target_pte_for_mc(struct vm_area_struct *vma, 4381 unsigned long addr, pte_t ptent, union mc_target *target) 4382{ 4383 struct page *page = NULL; 4384 struct page_cgroup *pc; 4385 int ret = 0; 4386 swp_entry_t ent = { .val = 0 }; 4387 4388 if (pte_present(ptent)) 4389 page = mc_handle_present_pte(vma, addr, ptent); 4390 else if (is_swap_pte(ptent)) 4391 page = mc_handle_swap_pte(vma, addr, ptent, &ent); 4392 else if (pte_none(ptent) || pte_file(ptent)) 4393 page = mc_handle_file_pte(vma, addr, ptent, &ent); 4394 4395 if (!page && !ent.val) 4396 return 0; 4397 if (page) { 4398 pc = lookup_page_cgroup(page); 4399 /* 4400 * Do only loose check w/o page_cgroup lock. 4401 * mem_cgroup_move_account() checks the pc is valid or not under 4402 * the lock. 4403 */ 4404 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { 4405 ret = MC_TARGET_PAGE; 4406 if (target) 4407 target->page = page; 4408 } 4409 if (!ret || !target) 4410 put_page(page); 4411 } 4412 /* There is a swap entry and a page doesn't exist or isn't charged */ 4413 if (ent.val && !ret && 4414 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { 4415 ret = MC_TARGET_SWAP; 4416 if (target) 4417 target->ent = ent; 4418 } 4419 return ret; 4420} 4421 4422static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, 4423 unsigned long addr, unsigned long end, 4424 struct mm_walk *walk) 4425{ 4426 struct vm_area_struct *vma = walk->private; 4427 pte_t *pte; 4428 spinlock_t *ptl; 4429 4430 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 4431 for (; addr != end; pte++, addr += PAGE_SIZE) 4432 if (is_target_pte_for_mc(vma, addr, *pte, NULL)) 4433 mc.precharge++; /* increment precharge temporarily */ 4434 pte_unmap_unlock(pte - 1, ptl); 4435 cond_resched(); 4436 4437 return 0; 4438} 4439 4440static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) 4441{ 4442 unsigned long precharge; 4443 struct vm_area_struct *vma; 4444 4445 down_read(&mm->mmap_sem); 4446 for (vma = mm->mmap; vma; vma = vma->vm_next) { 4447 struct mm_walk mem_cgroup_count_precharge_walk = { 4448 .pmd_entry = mem_cgroup_count_precharge_pte_range, 4449 .mm = mm, 4450 .private = vma, 4451 }; 4452 if (is_vm_hugetlb_page(vma)) 4453 continue; 4454 walk_page_range(vma->vm_start, vma->vm_end, 4455 &mem_cgroup_count_precharge_walk); 4456 } 4457 up_read(&mm->mmap_sem); 4458 4459 precharge = mc.precharge; 4460 mc.precharge = 0; 4461 4462 return precharge; 4463} 4464 4465static int mem_cgroup_precharge_mc(struct mm_struct *mm) 4466{ 4467 return mem_cgroup_do_precharge(mem_cgroup_count_precharge(mm)); 4468} 4469 4470static void mem_cgroup_clear_mc(void) 4471{ 4472 struct mem_cgroup *from = mc.from; 4473 struct mem_cgroup *to = mc.to; 4474 4475 /* we must uncharge all the leftover precharges from mc.to */ 4476 if (mc.precharge) { 4477 __mem_cgroup_cancel_charge(mc.to, mc.precharge); 4478 mc.precharge = 0; 4479 } 4480 /* 4481 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so 4482 * we must uncharge here. 4483 */ 4484 if (mc.moved_charge) { 4485 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); 4486 mc.moved_charge = 0; 4487 } 4488 /* we must fixup refcnts and charges */ 4489 if (mc.moved_swap) { 4490 /* uncharge swap account from the old cgroup */ 4491 if (!mem_cgroup_is_root(mc.from)) 4492 res_counter_uncharge(&mc.from->memsw, 4493 PAGE_SIZE * mc.moved_swap); 4494 __mem_cgroup_put(mc.from, mc.moved_swap); 4495 4496 if (!mem_cgroup_is_root(mc.to)) { 4497 /* 4498 * we charged both to->res and to->memsw, so we should 4499 * uncharge to->res. 4500 */ 4501 res_counter_uncharge(&mc.to->res, 4502 PAGE_SIZE * mc.moved_swap); 4503 } 4504 /* we've already done mem_cgroup_get(mc.to) */ 4505 4506 mc.moved_swap = 0; 4507 } 4508 spin_lock(&mc.lock); 4509 mc.from = NULL; 4510 mc.to = NULL; 4511 mc.moving_task = NULL; 4512 spin_unlock(&mc.lock); 4513 memcg_oom_recover(from); 4514 memcg_oom_recover(to); 4515 wake_up_all(&mc.waitq); 4516} 4517 4518static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 4519 struct cgroup *cgroup, 4520 struct task_struct *p, 4521 bool threadgroup) 4522{ 4523 int ret = 0; 4524 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup); 4525 4526 if (mem->move_charge_at_immigrate) { 4527 struct mm_struct *mm; 4528 struct mem_cgroup *from = mem_cgroup_from_task(p); 4529 4530 VM_BUG_ON(from == mem); 4531 4532 mm = get_task_mm(p); 4533 if (!mm) 4534 return 0; 4535 /* We move charges only when we move a owner of the mm */ 4536 if (mm->owner == p) { 4537 VM_BUG_ON(mc.from); 4538 VM_BUG_ON(mc.to); 4539 VM_BUG_ON(mc.precharge); 4540 VM_BUG_ON(mc.moved_charge); 4541 VM_BUG_ON(mc.moved_swap); 4542 VM_BUG_ON(mc.moving_task); 4543 spin_lock(&mc.lock); 4544 mc.from = from; 4545 mc.to = mem; 4546 mc.precharge = 0; 4547 mc.moved_charge = 0; 4548 mc.moved_swap = 0; 4549 mc.moving_task = current; 4550 spin_unlock(&mc.lock); 4551 4552 ret = mem_cgroup_precharge_mc(mm); 4553 if (ret) 4554 mem_cgroup_clear_mc(); 4555 } 4556 mmput(mm); 4557 } 4558 return ret; 4559} 4560 4561static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 4562 struct cgroup *cgroup, 4563 struct task_struct *p, 4564 bool threadgroup) 4565{ 4566 mem_cgroup_clear_mc(); 4567} 4568 4569static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, 4570 unsigned long addr, unsigned long end, 4571 struct mm_walk *walk) 4572{ 4573 int ret = 0; 4574 struct vm_area_struct *vma = walk->private; 4575 pte_t *pte; 4576 spinlock_t *ptl; 4577 4578retry: 4579 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 4580 for (; addr != end; addr += PAGE_SIZE) { 4581 pte_t ptent = *(pte++); 4582 union mc_target target; 4583 int type; 4584 struct page *page; 4585 struct page_cgroup *pc; 4586 swp_entry_t ent; 4587 4588 if (!mc.precharge) 4589 break; 4590 4591 type = is_target_pte_for_mc(vma, addr, ptent, &target); 4592 switch (type) { 4593 case MC_TARGET_PAGE: 4594 page = target.page; 4595 if (isolate_lru_page(page)) 4596 goto put; 4597 pc = lookup_page_cgroup(page); 4598 if (!mem_cgroup_move_account(pc, 4599 mc.from, mc.to, false)) { 4600 mc.precharge--; 4601 /* we uncharge from mc.from later. */ 4602 mc.moved_charge++; 4603 } 4604 putback_lru_page(page); 4605put: /* is_target_pte_for_mc() gets the page */ 4606 put_page(page); 4607 break; 4608 case MC_TARGET_SWAP: 4609 ent = target.ent; 4610 if (!mem_cgroup_move_swap_account(ent, 4611 mc.from, mc.to, false)) { 4612 mc.precharge--; 4613 /* we fixup refcnts and charges later. */ 4614 mc.moved_swap++; 4615 } 4616 break; 4617 default: 4618 break; 4619 } 4620 } 4621 pte_unmap_unlock(pte - 1, ptl); 4622 cond_resched(); 4623 4624 if (addr != end) { 4625 /* 4626 * We have consumed all precharges we got in can_attach(). 4627 * We try charge one by one, but don't do any additional 4628 * charges to mc.to if we have failed in charge once in attach() 4629 * phase. 4630 */ 4631 ret = mem_cgroup_do_precharge(1); 4632 if (!ret) 4633 goto retry; 4634 } 4635 4636 return ret; 4637} 4638 4639static void mem_cgroup_move_charge(struct mm_struct *mm) 4640{ 4641 struct vm_area_struct *vma; 4642 4643 lru_add_drain_all(); 4644 down_read(&mm->mmap_sem); 4645 for (vma = mm->mmap; vma; vma = vma->vm_next) { 4646 int ret; 4647 struct mm_walk mem_cgroup_move_charge_walk = { 4648 .pmd_entry = mem_cgroup_move_charge_pte_range, 4649 .mm = mm, 4650 .private = vma, 4651 }; 4652 if (is_vm_hugetlb_page(vma)) 4653 continue; 4654 ret = walk_page_range(vma->vm_start, vma->vm_end, 4655 &mem_cgroup_move_charge_walk); 4656 if (ret) 4657 /* 4658 * means we have consumed all precharges and failed in 4659 * doing additional charge. Just abandon here. 4660 */ 4661 break; 4662 } 4663 up_read(&mm->mmap_sem); 4664} 4665 4666static void mem_cgroup_move_task(struct cgroup_subsys *ss, 4667 struct cgroup *cont, 4668 struct cgroup *old_cont, 4669 struct task_struct *p, 4670 bool threadgroup) 4671{ 4672 struct mm_struct *mm; 4673 4674 if (!mc.to) 4675 /* no need to move charge */ 4676 return; 4677 4678 mm = get_task_mm(p); 4679 if (mm) { 4680 mem_cgroup_move_charge(mm); 4681 mmput(mm); 4682 } 4683 mem_cgroup_clear_mc(); 4684} 4685#else /* !CONFIG_MMU */ 4686static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 4687 struct cgroup *cgroup, 4688 struct task_struct *p, 4689 bool threadgroup) 4690{ 4691 return 0; 4692} 4693static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 4694 struct cgroup *cgroup, 4695 struct task_struct *p, 4696 bool threadgroup) 4697{ 4698} 4699static void mem_cgroup_move_task(struct cgroup_subsys *ss, 4700 struct cgroup *cont, 4701 struct cgroup *old_cont, 4702 struct task_struct *p, 4703 bool threadgroup) 4704{ 4705} 4706#endif 4707 4708struct cgroup_subsys mem_cgroup_subsys = { 4709 .name = "memory", 4710 .subsys_id = mem_cgroup_subsys_id, 4711 .create = mem_cgroup_create, 4712 .pre_destroy = mem_cgroup_pre_destroy, 4713 .destroy = mem_cgroup_destroy, 4714 .populate = mem_cgroup_populate, 4715 .can_attach = mem_cgroup_can_attach, 4716 .cancel_attach = mem_cgroup_cancel_attach, 4717 .attach = mem_cgroup_move_task, 4718 .early_init = 0, 4719 .use_id = 1, 4720}; 4721 4722#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4723 4724static int __init disable_swap_account(char *s) 4725{ 4726 really_do_swap_account = 0; 4727 return 1; 4728} 4729__setup("noswapaccount", disable_swap_account); 4730#endif 4731