memcontrol.c revision f780bdb7c1c73009cb57adcf99ef50027d80bf3c
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; 64 65/* for remember boot option*/ 66#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED 67static int really_do_swap_account __initdata = 1; 68#else 69static int really_do_swap_account __initdata = 0; 70#endif 71 72#else 73#define do_swap_account (0) 74#endif 75 76 77/* 78 * Statistics for memory cgroup. 79 */ 80enum mem_cgroup_stat_index { 81 /* 82 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss. 83 */ 84 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */ 85 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */ 86 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */ 87 MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */ 88 MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */ 89 MEM_CGROUP_ON_MOVE, /* someone is moving account between groups */ 90 MEM_CGROUP_STAT_NSTATS, 91}; 92 93enum mem_cgroup_events_index { 94 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */ 95 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */ 96 MEM_CGROUP_EVENTS_COUNT, /* # of pages paged in/out */ 97 MEM_CGROUP_EVENTS_NSTATS, 98}; 99/* 100 * Per memcg event counter is incremented at every pagein/pageout. With THP, 101 * it will be incremated by the number of pages. This counter is used for 102 * for trigger some periodic events. This is straightforward and better 103 * than using jiffies etc. to handle periodic memcg event. 104 */ 105enum mem_cgroup_events_target { 106 MEM_CGROUP_TARGET_THRESH, 107 MEM_CGROUP_TARGET_SOFTLIMIT, 108 MEM_CGROUP_NTARGETS, 109}; 110#define THRESHOLDS_EVENTS_TARGET (128) 111#define SOFTLIMIT_EVENTS_TARGET (1024) 112 113struct mem_cgroup_stat_cpu { 114 long count[MEM_CGROUP_STAT_NSTATS]; 115 unsigned long events[MEM_CGROUP_EVENTS_NSTATS]; 116 unsigned long targets[MEM_CGROUP_NTARGETS]; 117}; 118 119/* 120 * per-zone information in memory controller. 121 */ 122struct mem_cgroup_per_zone { 123 /* 124 * spin_lock to protect the per cgroup LRU 125 */ 126 struct list_head lists[NR_LRU_LISTS]; 127 unsigned long count[NR_LRU_LISTS]; 128 129 struct zone_reclaim_stat reclaim_stat; 130 struct rb_node tree_node; /* RB tree node */ 131 unsigned long long usage_in_excess;/* Set to the value by which */ 132 /* the soft limit is exceeded*/ 133 bool on_tree; 134 struct mem_cgroup *mem; /* Back pointer, we cannot */ 135 /* use container_of */ 136}; 137/* Macro for accessing counter */ 138#define MEM_CGROUP_ZSTAT(mz, idx) ((mz)->count[(idx)]) 139 140struct mem_cgroup_per_node { 141 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES]; 142}; 143 144struct mem_cgroup_lru_info { 145 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES]; 146}; 147 148/* 149 * Cgroups above their limits are maintained in a RB-Tree, independent of 150 * their hierarchy representation 151 */ 152 153struct mem_cgroup_tree_per_zone { 154 struct rb_root rb_root; 155 spinlock_t lock; 156}; 157 158struct mem_cgroup_tree_per_node { 159 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES]; 160}; 161 162struct mem_cgroup_tree { 163 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES]; 164}; 165 166static struct mem_cgroup_tree soft_limit_tree __read_mostly; 167 168struct mem_cgroup_threshold { 169 struct eventfd_ctx *eventfd; 170 u64 threshold; 171}; 172 173/* For threshold */ 174struct mem_cgroup_threshold_ary { 175 /* An array index points to threshold just below usage. */ 176 int current_threshold; 177 /* Size of entries[] */ 178 unsigned int size; 179 /* Array of thresholds */ 180 struct mem_cgroup_threshold entries[0]; 181}; 182 183struct mem_cgroup_thresholds { 184 /* Primary thresholds array */ 185 struct mem_cgroup_threshold_ary *primary; 186 /* 187 * Spare threshold array. 188 * This is needed to make mem_cgroup_unregister_event() "never fail". 189 * It must be able to store at least primary->size - 1 entries. 190 */ 191 struct mem_cgroup_threshold_ary *spare; 192}; 193 194/* for OOM */ 195struct mem_cgroup_eventfd_list { 196 struct list_head list; 197 struct eventfd_ctx *eventfd; 198}; 199 200static void mem_cgroup_threshold(struct mem_cgroup *mem); 201static void mem_cgroup_oom_notify(struct mem_cgroup *mem); 202 203/* 204 * The memory controller data structure. The memory controller controls both 205 * page cache and RSS per cgroup. We would eventually like to provide 206 * statistics based on the statistics developed by Rik Van Riel for clock-pro, 207 * to help the administrator determine what knobs to tune. 208 * 209 * TODO: Add a water mark for the memory controller. Reclaim will begin when 210 * we hit the water mark. May be even add a low water mark, such that 211 * no reclaim occurs from a cgroup at it's low water mark, this is 212 * a feature that will be implemented much later in the future. 213 */ 214struct mem_cgroup { 215 struct cgroup_subsys_state css; 216 /* 217 * the counter to account for memory usage 218 */ 219 struct res_counter res; 220 /* 221 * the counter to account for mem+swap usage. 222 */ 223 struct res_counter memsw; 224 /* 225 * Per cgroup active and inactive list, similar to the 226 * per zone LRU lists. 227 */ 228 struct mem_cgroup_lru_info info; 229 /* 230 * While reclaiming in a hierarchy, we cache the last child we 231 * reclaimed from. 232 */ 233 int last_scanned_child; 234 /* 235 * Should the accounting and control be hierarchical, per subtree? 236 */ 237 bool use_hierarchy; 238 atomic_t oom_lock; 239 atomic_t refcnt; 240 241 unsigned int swappiness; 242 /* OOM-Killer disable */ 243 int oom_kill_disable; 244 245 /* set when res.limit == memsw.limit */ 246 bool memsw_is_minimum; 247 248 /* protect arrays of thresholds */ 249 struct mutex thresholds_lock; 250 251 /* thresholds for memory usage. RCU-protected */ 252 struct mem_cgroup_thresholds thresholds; 253 254 /* thresholds for mem+swap usage. RCU-protected */ 255 struct mem_cgroup_thresholds memsw_thresholds; 256 257 /* For oom notifier event fd */ 258 struct list_head oom_notify; 259 260 /* 261 * Should we move charges of a task when a task is moved into this 262 * mem_cgroup ? And what type of charges should we move ? 263 */ 264 unsigned long move_charge_at_immigrate; 265 /* 266 * percpu counter. 267 */ 268 struct mem_cgroup_stat_cpu *stat; 269 /* 270 * used when a cpu is offlined or other synchronizations 271 * See mem_cgroup_read_stat(). 272 */ 273 struct mem_cgroup_stat_cpu nocpu_base; 274 spinlock_t pcp_counter_lock; 275}; 276 277/* Stuffs for move charges at task migration. */ 278/* 279 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a 280 * left-shifted bitmap of these types. 281 */ 282enum move_type { 283 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */ 284 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */ 285 NR_MOVE_TYPE, 286}; 287 288/* "mc" and its members are protected by cgroup_mutex */ 289static struct move_charge_struct { 290 spinlock_t lock; /* for from, to */ 291 struct mem_cgroup *from; 292 struct mem_cgroup *to; 293 unsigned long precharge; 294 unsigned long moved_charge; 295 unsigned long moved_swap; 296 struct task_struct *moving_task; /* a task moving charges */ 297 wait_queue_head_t waitq; /* a waitq for other context */ 298} mc = { 299 .lock = __SPIN_LOCK_UNLOCKED(mc.lock), 300 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq), 301}; 302 303static bool move_anon(void) 304{ 305 return test_bit(MOVE_CHARGE_TYPE_ANON, 306 &mc.to->move_charge_at_immigrate); 307} 308 309static bool move_file(void) 310{ 311 return test_bit(MOVE_CHARGE_TYPE_FILE, 312 &mc.to->move_charge_at_immigrate); 313} 314 315/* 316 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft 317 * limit reclaim to prevent infinite loops, if they ever occur. 318 */ 319#define MEM_CGROUP_MAX_RECLAIM_LOOPS (100) 320#define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS (2) 321 322enum charge_type { 323 MEM_CGROUP_CHARGE_TYPE_CACHE = 0, 324 MEM_CGROUP_CHARGE_TYPE_MAPPED, 325 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */ 326 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */ 327 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */ 328 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */ 329 NR_CHARGE_TYPE, 330}; 331 332/* for encoding cft->private value on file */ 333#define _MEM (0) 334#define _MEMSWAP (1) 335#define _OOM_TYPE (2) 336#define MEMFILE_PRIVATE(x, val) (((x) << 16) | (val)) 337#define MEMFILE_TYPE(val) (((val) >> 16) & 0xffff) 338#define MEMFILE_ATTR(val) ((val) & 0xffff) 339/* Used for OOM nofiier */ 340#define OOM_CONTROL (0) 341 342/* 343 * Reclaim flags for mem_cgroup_hierarchical_reclaim 344 */ 345#define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0 346#define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT) 347#define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1 348#define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT) 349#define MEM_CGROUP_RECLAIM_SOFT_BIT 0x2 350#define MEM_CGROUP_RECLAIM_SOFT (1 << MEM_CGROUP_RECLAIM_SOFT_BIT) 351 352static void mem_cgroup_get(struct mem_cgroup *mem); 353static void mem_cgroup_put(struct mem_cgroup *mem); 354static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem); 355static void drain_all_stock_async(void); 356 357static struct mem_cgroup_per_zone * 358mem_cgroup_zoneinfo(struct mem_cgroup *mem, int nid, int zid) 359{ 360 return &mem->info.nodeinfo[nid]->zoneinfo[zid]; 361} 362 363struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *mem) 364{ 365 return &mem->css; 366} 367 368static struct mem_cgroup_per_zone * 369page_cgroup_zoneinfo(struct mem_cgroup *mem, struct page *page) 370{ 371 int nid = page_to_nid(page); 372 int zid = page_zonenum(page); 373 374 return mem_cgroup_zoneinfo(mem, nid, zid); 375} 376 377static struct mem_cgroup_tree_per_zone * 378soft_limit_tree_node_zone(int nid, int zid) 379{ 380 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 381} 382 383static struct mem_cgroup_tree_per_zone * 384soft_limit_tree_from_page(struct page *page) 385{ 386 int nid = page_to_nid(page); 387 int zid = page_zonenum(page); 388 389 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid]; 390} 391 392static void 393__mem_cgroup_insert_exceeded(struct mem_cgroup *mem, 394 struct mem_cgroup_per_zone *mz, 395 struct mem_cgroup_tree_per_zone *mctz, 396 unsigned long long new_usage_in_excess) 397{ 398 struct rb_node **p = &mctz->rb_root.rb_node; 399 struct rb_node *parent = NULL; 400 struct mem_cgroup_per_zone *mz_node; 401 402 if (mz->on_tree) 403 return; 404 405 mz->usage_in_excess = new_usage_in_excess; 406 if (!mz->usage_in_excess) 407 return; 408 while (*p) { 409 parent = *p; 410 mz_node = rb_entry(parent, struct mem_cgroup_per_zone, 411 tree_node); 412 if (mz->usage_in_excess < mz_node->usage_in_excess) 413 p = &(*p)->rb_left; 414 /* 415 * We can't avoid mem cgroups that are over their soft 416 * limit by the same amount 417 */ 418 else if (mz->usage_in_excess >= mz_node->usage_in_excess) 419 p = &(*p)->rb_right; 420 } 421 rb_link_node(&mz->tree_node, parent, p); 422 rb_insert_color(&mz->tree_node, &mctz->rb_root); 423 mz->on_tree = true; 424} 425 426static void 427__mem_cgroup_remove_exceeded(struct mem_cgroup *mem, 428 struct mem_cgroup_per_zone *mz, 429 struct mem_cgroup_tree_per_zone *mctz) 430{ 431 if (!mz->on_tree) 432 return; 433 rb_erase(&mz->tree_node, &mctz->rb_root); 434 mz->on_tree = false; 435} 436 437static void 438mem_cgroup_remove_exceeded(struct mem_cgroup *mem, 439 struct mem_cgroup_per_zone *mz, 440 struct mem_cgroup_tree_per_zone *mctz) 441{ 442 spin_lock(&mctz->lock); 443 __mem_cgroup_remove_exceeded(mem, mz, mctz); 444 spin_unlock(&mctz->lock); 445} 446 447 448static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) 449{ 450 unsigned long long excess; 451 struct mem_cgroup_per_zone *mz; 452 struct mem_cgroup_tree_per_zone *mctz; 453 int nid = page_to_nid(page); 454 int zid = page_zonenum(page); 455 mctz = soft_limit_tree_from_page(page); 456 457 /* 458 * Necessary to update all ancestors when hierarchy is used. 459 * because their event counter is not touched. 460 */ 461 for (; mem; mem = parent_mem_cgroup(mem)) { 462 mz = mem_cgroup_zoneinfo(mem, nid, zid); 463 excess = res_counter_soft_limit_excess(&mem->res); 464 /* 465 * We have to update the tree if mz is on RB-tree or 466 * mem is over its softlimit. 467 */ 468 if (excess || mz->on_tree) { 469 spin_lock(&mctz->lock); 470 /* if on-tree, remove it */ 471 if (mz->on_tree) 472 __mem_cgroup_remove_exceeded(mem, mz, mctz); 473 /* 474 * Insert again. mz->usage_in_excess will be updated. 475 * If excess is 0, no tree ops. 476 */ 477 __mem_cgroup_insert_exceeded(mem, mz, mctz, excess); 478 spin_unlock(&mctz->lock); 479 } 480 } 481} 482 483static void mem_cgroup_remove_from_trees(struct mem_cgroup *mem) 484{ 485 int node, zone; 486 struct mem_cgroup_per_zone *mz; 487 struct mem_cgroup_tree_per_zone *mctz; 488 489 for_each_node_state(node, N_POSSIBLE) { 490 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 491 mz = mem_cgroup_zoneinfo(mem, node, zone); 492 mctz = soft_limit_tree_node_zone(node, zone); 493 mem_cgroup_remove_exceeded(mem, mz, mctz); 494 } 495 } 496} 497 498static struct mem_cgroup_per_zone * 499__mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 500{ 501 struct rb_node *rightmost = NULL; 502 struct mem_cgroup_per_zone *mz; 503 504retry: 505 mz = NULL; 506 rightmost = rb_last(&mctz->rb_root); 507 if (!rightmost) 508 goto done; /* Nothing to reclaim from */ 509 510 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node); 511 /* 512 * Remove the node now but someone else can add it back, 513 * we will to add it back at the end of reclaim to its correct 514 * position in the tree. 515 */ 516 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 517 if (!res_counter_soft_limit_excess(&mz->mem->res) || 518 !css_tryget(&mz->mem->css)) 519 goto retry; 520done: 521 return mz; 522} 523 524static struct mem_cgroup_per_zone * 525mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz) 526{ 527 struct mem_cgroup_per_zone *mz; 528 529 spin_lock(&mctz->lock); 530 mz = __mem_cgroup_largest_soft_limit_node(mctz); 531 spin_unlock(&mctz->lock); 532 return mz; 533} 534 535/* 536 * Implementation Note: reading percpu statistics for memcg. 537 * 538 * Both of vmstat[] and percpu_counter has threshold and do periodic 539 * synchronization to implement "quick" read. There are trade-off between 540 * reading cost and precision of value. Then, we may have a chance to implement 541 * a periodic synchronizion of counter in memcg's counter. 542 * 543 * But this _read() function is used for user interface now. The user accounts 544 * memory usage by memory cgroup and he _always_ requires exact value because 545 * he accounts memory. Even if we provide quick-and-fuzzy read, we always 546 * have to visit all online cpus and make sum. So, for now, unnecessary 547 * synchronization is not implemented. (just implemented for cpu hotplug) 548 * 549 * If there are kernel internal actions which can make use of some not-exact 550 * value, and reading all cpu value can be performance bottleneck in some 551 * common workload, threashold and synchonization as vmstat[] should be 552 * implemented. 553 */ 554static long mem_cgroup_read_stat(struct mem_cgroup *mem, 555 enum mem_cgroup_stat_index idx) 556{ 557 long val = 0; 558 int cpu; 559 560 get_online_cpus(); 561 for_each_online_cpu(cpu) 562 val += per_cpu(mem->stat->count[idx], cpu); 563#ifdef CONFIG_HOTPLUG_CPU 564 spin_lock(&mem->pcp_counter_lock); 565 val += mem->nocpu_base.count[idx]; 566 spin_unlock(&mem->pcp_counter_lock); 567#endif 568 put_online_cpus(); 569 return val; 570} 571 572static long mem_cgroup_local_usage(struct mem_cgroup *mem) 573{ 574 long ret; 575 576 ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); 577 ret += mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); 578 return ret; 579} 580 581static void mem_cgroup_swap_statistics(struct mem_cgroup *mem, 582 bool charge) 583{ 584 int val = (charge) ? 1 : -1; 585 this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_SWAPOUT], val); 586} 587 588static unsigned long mem_cgroup_read_events(struct mem_cgroup *mem, 589 enum mem_cgroup_events_index idx) 590{ 591 unsigned long val = 0; 592 int cpu; 593 594 for_each_online_cpu(cpu) 595 val += per_cpu(mem->stat->events[idx], cpu); 596#ifdef CONFIG_HOTPLUG_CPU 597 spin_lock(&mem->pcp_counter_lock); 598 val += mem->nocpu_base.events[idx]; 599 spin_unlock(&mem->pcp_counter_lock); 600#endif 601 return val; 602} 603 604static void mem_cgroup_charge_statistics(struct mem_cgroup *mem, 605 bool file, int nr_pages) 606{ 607 preempt_disable(); 608 609 if (file) 610 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_CACHE], nr_pages); 611 else 612 __this_cpu_add(mem->stat->count[MEM_CGROUP_STAT_RSS], nr_pages); 613 614 /* pagein of a big page is an event. So, ignore page size */ 615 if (nr_pages > 0) 616 __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGIN]); 617 else { 618 __this_cpu_inc(mem->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]); 619 nr_pages = -nr_pages; /* for event */ 620 } 621 622 __this_cpu_add(mem->stat->events[MEM_CGROUP_EVENTS_COUNT], nr_pages); 623 624 preempt_enable(); 625} 626 627static unsigned long mem_cgroup_get_local_zonestat(struct mem_cgroup *mem, 628 enum lru_list idx) 629{ 630 int nid, zid; 631 struct mem_cgroup_per_zone *mz; 632 u64 total = 0; 633 634 for_each_online_node(nid) 635 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 636 mz = mem_cgroup_zoneinfo(mem, nid, zid); 637 total += MEM_CGROUP_ZSTAT(mz, idx); 638 } 639 return total; 640} 641 642static bool __memcg_event_check(struct mem_cgroup *mem, int target) 643{ 644 unsigned long val, next; 645 646 val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]); 647 next = this_cpu_read(mem->stat->targets[target]); 648 /* from time_after() in jiffies.h */ 649 return ((long)next - (long)val < 0); 650} 651 652static void __mem_cgroup_target_update(struct mem_cgroup *mem, int target) 653{ 654 unsigned long val, next; 655 656 val = this_cpu_read(mem->stat->events[MEM_CGROUP_EVENTS_COUNT]); 657 658 switch (target) { 659 case MEM_CGROUP_TARGET_THRESH: 660 next = val + THRESHOLDS_EVENTS_TARGET; 661 break; 662 case MEM_CGROUP_TARGET_SOFTLIMIT: 663 next = val + SOFTLIMIT_EVENTS_TARGET; 664 break; 665 default: 666 return; 667 } 668 669 this_cpu_write(mem->stat->targets[target], next); 670} 671 672/* 673 * Check events in order. 674 * 675 */ 676static void memcg_check_events(struct mem_cgroup *mem, struct page *page) 677{ 678 /* threshold event is triggered in finer grain than soft limit */ 679 if (unlikely(__memcg_event_check(mem, MEM_CGROUP_TARGET_THRESH))) { 680 mem_cgroup_threshold(mem); 681 __mem_cgroup_target_update(mem, MEM_CGROUP_TARGET_THRESH); 682 if (unlikely(__memcg_event_check(mem, 683 MEM_CGROUP_TARGET_SOFTLIMIT))){ 684 mem_cgroup_update_tree(mem, page); 685 __mem_cgroup_target_update(mem, 686 MEM_CGROUP_TARGET_SOFTLIMIT); 687 } 688 } 689} 690 691static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont) 692{ 693 return container_of(cgroup_subsys_state(cont, 694 mem_cgroup_subsys_id), struct mem_cgroup, 695 css); 696} 697 698struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p) 699{ 700 /* 701 * mm_update_next_owner() may clear mm->owner to NULL 702 * if it races with swapoff, page migration, etc. 703 * So this can be called with p == NULL. 704 */ 705 if (unlikely(!p)) 706 return NULL; 707 708 return container_of(task_subsys_state(p, mem_cgroup_subsys_id), 709 struct mem_cgroup, css); 710} 711 712static struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm) 713{ 714 struct mem_cgroup *mem = NULL; 715 716 if (!mm) 717 return NULL; 718 /* 719 * Because we have no locks, mm->owner's may be being moved to other 720 * cgroup. We use css_tryget() here even if this looks 721 * pessimistic (rather than adding locks here). 722 */ 723 rcu_read_lock(); 724 do { 725 mem = mem_cgroup_from_task(rcu_dereference(mm->owner)); 726 if (unlikely(!mem)) 727 break; 728 } while (!css_tryget(&mem->css)); 729 rcu_read_unlock(); 730 return mem; 731} 732 733/* The caller has to guarantee "mem" exists before calling this */ 734static struct mem_cgroup *mem_cgroup_start_loop(struct mem_cgroup *mem) 735{ 736 struct cgroup_subsys_state *css; 737 int found; 738 739 if (!mem) /* ROOT cgroup has the smallest ID */ 740 return root_mem_cgroup; /*css_put/get against root is ignored*/ 741 if (!mem->use_hierarchy) { 742 if (css_tryget(&mem->css)) 743 return mem; 744 return NULL; 745 } 746 rcu_read_lock(); 747 /* 748 * searching a memory cgroup which has the smallest ID under given 749 * ROOT cgroup. (ID >= 1) 750 */ 751 css = css_get_next(&mem_cgroup_subsys, 1, &mem->css, &found); 752 if (css && css_tryget(css)) 753 mem = container_of(css, struct mem_cgroup, css); 754 else 755 mem = NULL; 756 rcu_read_unlock(); 757 return mem; 758} 759 760static struct mem_cgroup *mem_cgroup_get_next(struct mem_cgroup *iter, 761 struct mem_cgroup *root, 762 bool cond) 763{ 764 int nextid = css_id(&iter->css) + 1; 765 int found; 766 int hierarchy_used; 767 struct cgroup_subsys_state *css; 768 769 hierarchy_used = iter->use_hierarchy; 770 771 css_put(&iter->css); 772 /* If no ROOT, walk all, ignore hierarchy */ 773 if (!cond || (root && !hierarchy_used)) 774 return NULL; 775 776 if (!root) 777 root = root_mem_cgroup; 778 779 do { 780 iter = NULL; 781 rcu_read_lock(); 782 783 css = css_get_next(&mem_cgroup_subsys, nextid, 784 &root->css, &found); 785 if (css && css_tryget(css)) 786 iter = container_of(css, struct mem_cgroup, css); 787 rcu_read_unlock(); 788 /* If css is NULL, no more cgroups will be found */ 789 nextid = found + 1; 790 } while (css && !iter); 791 792 return iter; 793} 794/* 795 * for_eacn_mem_cgroup_tree() for visiting all cgroup under tree. Please 796 * be careful that "break" loop is not allowed. We have reference count. 797 * Instead of that modify "cond" to be false and "continue" to exit the loop. 798 */ 799#define for_each_mem_cgroup_tree_cond(iter, root, cond) \ 800 for (iter = mem_cgroup_start_loop(root);\ 801 iter != NULL;\ 802 iter = mem_cgroup_get_next(iter, root, cond)) 803 804#define for_each_mem_cgroup_tree(iter, root) \ 805 for_each_mem_cgroup_tree_cond(iter, root, true) 806 807#define for_each_mem_cgroup_all(iter) \ 808 for_each_mem_cgroup_tree_cond(iter, NULL, true) 809 810 811static inline bool mem_cgroup_is_root(struct mem_cgroup *mem) 812{ 813 return (mem == root_mem_cgroup); 814} 815 816/* 817 * Following LRU functions are allowed to be used without PCG_LOCK. 818 * Operations are called by routine of global LRU independently from memcg. 819 * What we have to take care of here is validness of pc->mem_cgroup. 820 * 821 * Changes to pc->mem_cgroup happens when 822 * 1. charge 823 * 2. moving account 824 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache. 825 * It is added to LRU before charge. 826 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU. 827 * When moving account, the page is not on LRU. It's isolated. 828 */ 829 830void mem_cgroup_del_lru_list(struct page *page, enum lru_list lru) 831{ 832 struct page_cgroup *pc; 833 struct mem_cgroup_per_zone *mz; 834 835 if (mem_cgroup_disabled()) 836 return; 837 pc = lookup_page_cgroup(page); 838 /* can happen while we handle swapcache. */ 839 if (!TestClearPageCgroupAcctLRU(pc)) 840 return; 841 VM_BUG_ON(!pc->mem_cgroup); 842 /* 843 * We don't check PCG_USED bit. It's cleared when the "page" is finally 844 * removed from global LRU. 845 */ 846 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 847 /* huge page split is done under lru_lock. so, we have no races. */ 848 MEM_CGROUP_ZSTAT(mz, lru) -= 1 << compound_order(page); 849 if (mem_cgroup_is_root(pc->mem_cgroup)) 850 return; 851 VM_BUG_ON(list_empty(&pc->lru)); 852 list_del_init(&pc->lru); 853} 854 855void mem_cgroup_del_lru(struct page *page) 856{ 857 mem_cgroup_del_lru_list(page, page_lru(page)); 858} 859 860/* 861 * Writeback is about to end against a page which has been marked for immediate 862 * reclaim. If it still appears to be reclaimable, move it to the tail of the 863 * inactive list. 864 */ 865void mem_cgroup_rotate_reclaimable_page(struct page *page) 866{ 867 struct mem_cgroup_per_zone *mz; 868 struct page_cgroup *pc; 869 enum lru_list lru = page_lru(page); 870 871 if (mem_cgroup_disabled()) 872 return; 873 874 pc = lookup_page_cgroup(page); 875 /* unused or root page is not rotated. */ 876 if (!PageCgroupUsed(pc)) 877 return; 878 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 879 smp_rmb(); 880 if (mem_cgroup_is_root(pc->mem_cgroup)) 881 return; 882 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 883 list_move_tail(&pc->lru, &mz->lists[lru]); 884} 885 886void mem_cgroup_rotate_lru_list(struct page *page, enum lru_list lru) 887{ 888 struct mem_cgroup_per_zone *mz; 889 struct page_cgroup *pc; 890 891 if (mem_cgroup_disabled()) 892 return; 893 894 pc = lookup_page_cgroup(page); 895 /* unused or root page is not rotated. */ 896 if (!PageCgroupUsed(pc)) 897 return; 898 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 899 smp_rmb(); 900 if (mem_cgroup_is_root(pc->mem_cgroup)) 901 return; 902 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 903 list_move(&pc->lru, &mz->lists[lru]); 904} 905 906void mem_cgroup_add_lru_list(struct page *page, enum lru_list lru) 907{ 908 struct page_cgroup *pc; 909 struct mem_cgroup_per_zone *mz; 910 911 if (mem_cgroup_disabled()) 912 return; 913 pc = lookup_page_cgroup(page); 914 VM_BUG_ON(PageCgroupAcctLRU(pc)); 915 if (!PageCgroupUsed(pc)) 916 return; 917 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 918 smp_rmb(); 919 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 920 /* huge page split is done under lru_lock. so, we have no races. */ 921 MEM_CGROUP_ZSTAT(mz, lru) += 1 << compound_order(page); 922 SetPageCgroupAcctLRU(pc); 923 if (mem_cgroup_is_root(pc->mem_cgroup)) 924 return; 925 list_add(&pc->lru, &mz->lists[lru]); 926} 927 928/* 929 * At handling SwapCache and other FUSE stuff, pc->mem_cgroup may be changed 930 * while it's linked to lru because the page may be reused after it's fully 931 * uncharged. To handle that, unlink page_cgroup from LRU when charge it again. 932 * It's done under lock_page and expected that zone->lru_lock isnever held. 933 */ 934static void mem_cgroup_lru_del_before_commit(struct page *page) 935{ 936 unsigned long flags; 937 struct zone *zone = page_zone(page); 938 struct page_cgroup *pc = lookup_page_cgroup(page); 939 940 /* 941 * Doing this check without taking ->lru_lock seems wrong but this 942 * is safe. Because if page_cgroup's USED bit is unset, the page 943 * will not be added to any memcg's LRU. If page_cgroup's USED bit is 944 * set, the commit after this will fail, anyway. 945 * This all charge/uncharge is done under some mutual execustion. 946 * So, we don't need to taking care of changes in USED bit. 947 */ 948 if (likely(!PageLRU(page))) 949 return; 950 951 spin_lock_irqsave(&zone->lru_lock, flags); 952 /* 953 * Forget old LRU when this page_cgroup is *not* used. This Used bit 954 * is guarded by lock_page() because the page is SwapCache. 955 */ 956 if (!PageCgroupUsed(pc)) 957 mem_cgroup_del_lru_list(page, page_lru(page)); 958 spin_unlock_irqrestore(&zone->lru_lock, flags); 959} 960 961static void mem_cgroup_lru_add_after_commit(struct page *page) 962{ 963 unsigned long flags; 964 struct zone *zone = page_zone(page); 965 struct page_cgroup *pc = lookup_page_cgroup(page); 966 967 /* taking care of that the page is added to LRU while we commit it */ 968 if (likely(!PageLRU(page))) 969 return; 970 spin_lock_irqsave(&zone->lru_lock, flags); 971 /* link when the page is linked to LRU but page_cgroup isn't */ 972 if (PageLRU(page) && !PageCgroupAcctLRU(pc)) 973 mem_cgroup_add_lru_list(page, page_lru(page)); 974 spin_unlock_irqrestore(&zone->lru_lock, flags); 975} 976 977 978void mem_cgroup_move_lists(struct page *page, 979 enum lru_list from, enum lru_list to) 980{ 981 if (mem_cgroup_disabled()) 982 return; 983 mem_cgroup_del_lru_list(page, from); 984 mem_cgroup_add_lru_list(page, to); 985} 986 987int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *mem) 988{ 989 int ret; 990 struct mem_cgroup *curr = NULL; 991 struct task_struct *p; 992 993 p = find_lock_task_mm(task); 994 if (!p) 995 return 0; 996 curr = try_get_mem_cgroup_from_mm(p->mm); 997 task_unlock(p); 998 if (!curr) 999 return 0; 1000 /* 1001 * We should check use_hierarchy of "mem" not "curr". Because checking 1002 * use_hierarchy of "curr" here make this function true if hierarchy is 1003 * enabled in "curr" and "curr" is a child of "mem" in *cgroup* 1004 * hierarchy(even if use_hierarchy is disabled in "mem"). 1005 */ 1006 if (mem->use_hierarchy) 1007 ret = css_is_ancestor(&curr->css, &mem->css); 1008 else 1009 ret = (curr == mem); 1010 css_put(&curr->css); 1011 return ret; 1012} 1013 1014static int calc_inactive_ratio(struct mem_cgroup *memcg, unsigned long *present_pages) 1015{ 1016 unsigned long active; 1017 unsigned long inactive; 1018 unsigned long gb; 1019 unsigned long inactive_ratio; 1020 1021 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_ANON); 1022 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_ANON); 1023 1024 gb = (inactive + active) >> (30 - PAGE_SHIFT); 1025 if (gb) 1026 inactive_ratio = int_sqrt(10 * gb); 1027 else 1028 inactive_ratio = 1; 1029 1030 if (present_pages) { 1031 present_pages[0] = inactive; 1032 present_pages[1] = active; 1033 } 1034 1035 return inactive_ratio; 1036} 1037 1038int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg) 1039{ 1040 unsigned long active; 1041 unsigned long inactive; 1042 unsigned long present_pages[2]; 1043 unsigned long inactive_ratio; 1044 1045 inactive_ratio = calc_inactive_ratio(memcg, present_pages); 1046 1047 inactive = present_pages[0]; 1048 active = present_pages[1]; 1049 1050 if (inactive * inactive_ratio < active) 1051 return 1; 1052 1053 return 0; 1054} 1055 1056int mem_cgroup_inactive_file_is_low(struct mem_cgroup *memcg) 1057{ 1058 unsigned long active; 1059 unsigned long inactive; 1060 1061 inactive = mem_cgroup_get_local_zonestat(memcg, LRU_INACTIVE_FILE); 1062 active = mem_cgroup_get_local_zonestat(memcg, LRU_ACTIVE_FILE); 1063 1064 return (active > inactive); 1065} 1066 1067unsigned long mem_cgroup_zone_nr_pages(struct mem_cgroup *memcg, 1068 struct zone *zone, 1069 enum lru_list lru) 1070{ 1071 int nid = zone_to_nid(zone); 1072 int zid = zone_idx(zone); 1073 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 1074 1075 return MEM_CGROUP_ZSTAT(mz, lru); 1076} 1077 1078struct zone_reclaim_stat *mem_cgroup_get_reclaim_stat(struct mem_cgroup *memcg, 1079 struct zone *zone) 1080{ 1081 int nid = zone_to_nid(zone); 1082 int zid = zone_idx(zone); 1083 struct mem_cgroup_per_zone *mz = mem_cgroup_zoneinfo(memcg, nid, zid); 1084 1085 return &mz->reclaim_stat; 1086} 1087 1088struct zone_reclaim_stat * 1089mem_cgroup_get_reclaim_stat_from_page(struct page *page) 1090{ 1091 struct page_cgroup *pc; 1092 struct mem_cgroup_per_zone *mz; 1093 1094 if (mem_cgroup_disabled()) 1095 return NULL; 1096 1097 pc = lookup_page_cgroup(page); 1098 if (!PageCgroupUsed(pc)) 1099 return NULL; 1100 /* Ensure pc->mem_cgroup is visible after reading PCG_USED. */ 1101 smp_rmb(); 1102 mz = page_cgroup_zoneinfo(pc->mem_cgroup, page); 1103 return &mz->reclaim_stat; 1104} 1105 1106unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan, 1107 struct list_head *dst, 1108 unsigned long *scanned, int order, 1109 int mode, struct zone *z, 1110 struct mem_cgroup *mem_cont, 1111 int active, int file) 1112{ 1113 unsigned long nr_taken = 0; 1114 struct page *page; 1115 unsigned long scan; 1116 LIST_HEAD(pc_list); 1117 struct list_head *src; 1118 struct page_cgroup *pc, *tmp; 1119 int nid = zone_to_nid(z); 1120 int zid = zone_idx(z); 1121 struct mem_cgroup_per_zone *mz; 1122 int lru = LRU_FILE * file + active; 1123 int ret; 1124 1125 BUG_ON(!mem_cont); 1126 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 1127 src = &mz->lists[lru]; 1128 1129 scan = 0; 1130 list_for_each_entry_safe_reverse(pc, tmp, src, lru) { 1131 if (scan >= nr_to_scan) 1132 break; 1133 1134 if (unlikely(!PageCgroupUsed(pc))) 1135 continue; 1136 1137 page = lookup_cgroup_page(pc); 1138 1139 if (unlikely(!PageLRU(page))) 1140 continue; 1141 1142 scan++; 1143 ret = __isolate_lru_page(page, mode, file); 1144 switch (ret) { 1145 case 0: 1146 list_move(&page->lru, dst); 1147 mem_cgroup_del_lru(page); 1148 nr_taken += hpage_nr_pages(page); 1149 break; 1150 case -EBUSY: 1151 /* we don't affect global LRU but rotate in our LRU */ 1152 mem_cgroup_rotate_lru_list(page, page_lru(page)); 1153 break; 1154 default: 1155 break; 1156 } 1157 } 1158 1159 *scanned = scan; 1160 1161 trace_mm_vmscan_memcg_isolate(0, nr_to_scan, scan, nr_taken, 1162 0, 0, 0, mode); 1163 1164 return nr_taken; 1165} 1166 1167#define mem_cgroup_from_res_counter(counter, member) \ 1168 container_of(counter, struct mem_cgroup, member) 1169 1170/** 1171 * mem_cgroup_margin - calculate chargeable space of a memory cgroup 1172 * @mem: the memory cgroup 1173 * 1174 * Returns the maximum amount of memory @mem can be charged with, in 1175 * pages. 1176 */ 1177static unsigned long mem_cgroup_margin(struct mem_cgroup *mem) 1178{ 1179 unsigned long long margin; 1180 1181 margin = res_counter_margin(&mem->res); 1182 if (do_swap_account) 1183 margin = min(margin, res_counter_margin(&mem->memsw)); 1184 return margin >> PAGE_SHIFT; 1185} 1186 1187static unsigned int get_swappiness(struct mem_cgroup *memcg) 1188{ 1189 struct cgroup *cgrp = memcg->css.cgroup; 1190 1191 /* root ? */ 1192 if (cgrp->parent == NULL) 1193 return vm_swappiness; 1194 1195 return memcg->swappiness; 1196} 1197 1198static void mem_cgroup_start_move(struct mem_cgroup *mem) 1199{ 1200 int cpu; 1201 1202 get_online_cpus(); 1203 spin_lock(&mem->pcp_counter_lock); 1204 for_each_online_cpu(cpu) 1205 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) += 1; 1206 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] += 1; 1207 spin_unlock(&mem->pcp_counter_lock); 1208 put_online_cpus(); 1209 1210 synchronize_rcu(); 1211} 1212 1213static void mem_cgroup_end_move(struct mem_cgroup *mem) 1214{ 1215 int cpu; 1216 1217 if (!mem) 1218 return; 1219 get_online_cpus(); 1220 spin_lock(&mem->pcp_counter_lock); 1221 for_each_online_cpu(cpu) 1222 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) -= 1; 1223 mem->nocpu_base.count[MEM_CGROUP_ON_MOVE] -= 1; 1224 spin_unlock(&mem->pcp_counter_lock); 1225 put_online_cpus(); 1226} 1227/* 1228 * 2 routines for checking "mem" is under move_account() or not. 1229 * 1230 * mem_cgroup_stealed() - checking a cgroup is mc.from or not. This is used 1231 * for avoiding race in accounting. If true, 1232 * pc->mem_cgroup may be overwritten. 1233 * 1234 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or 1235 * under hierarchy of moving cgroups. This is for 1236 * waiting at hith-memory prressure caused by "move". 1237 */ 1238 1239static bool mem_cgroup_stealed(struct mem_cgroup *mem) 1240{ 1241 VM_BUG_ON(!rcu_read_lock_held()); 1242 return this_cpu_read(mem->stat->count[MEM_CGROUP_ON_MOVE]) > 0; 1243} 1244 1245static bool mem_cgroup_under_move(struct mem_cgroup *mem) 1246{ 1247 struct mem_cgroup *from; 1248 struct mem_cgroup *to; 1249 bool ret = false; 1250 /* 1251 * Unlike task_move routines, we access mc.to, mc.from not under 1252 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead. 1253 */ 1254 spin_lock(&mc.lock); 1255 from = mc.from; 1256 to = mc.to; 1257 if (!from) 1258 goto unlock; 1259 if (from == mem || to == mem 1260 || (mem->use_hierarchy && css_is_ancestor(&from->css, &mem->css)) 1261 || (mem->use_hierarchy && css_is_ancestor(&to->css, &mem->css))) 1262 ret = true; 1263unlock: 1264 spin_unlock(&mc.lock); 1265 return ret; 1266} 1267 1268static bool mem_cgroup_wait_acct_move(struct mem_cgroup *mem) 1269{ 1270 if (mc.moving_task && current != mc.moving_task) { 1271 if (mem_cgroup_under_move(mem)) { 1272 DEFINE_WAIT(wait); 1273 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE); 1274 /* moving charge context might have finished. */ 1275 if (mc.moving_task) 1276 schedule(); 1277 finish_wait(&mc.waitq, &wait); 1278 return true; 1279 } 1280 } 1281 return false; 1282} 1283 1284/** 1285 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode. 1286 * @memcg: The memory cgroup that went over limit 1287 * @p: Task that is going to be killed 1288 * 1289 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is 1290 * enabled 1291 */ 1292void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 1293{ 1294 struct cgroup *task_cgrp; 1295 struct cgroup *mem_cgrp; 1296 /* 1297 * Need a buffer in BSS, can't rely on allocations. The code relies 1298 * on the assumption that OOM is serialized for memory controller. 1299 * If this assumption is broken, revisit this code. 1300 */ 1301 static char memcg_name[PATH_MAX]; 1302 int ret; 1303 1304 if (!memcg || !p) 1305 return; 1306 1307 1308 rcu_read_lock(); 1309 1310 mem_cgrp = memcg->css.cgroup; 1311 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id); 1312 1313 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX); 1314 if (ret < 0) { 1315 /* 1316 * Unfortunately, we are unable to convert to a useful name 1317 * But we'll still print out the usage information 1318 */ 1319 rcu_read_unlock(); 1320 goto done; 1321 } 1322 rcu_read_unlock(); 1323 1324 printk(KERN_INFO "Task in %s killed", memcg_name); 1325 1326 rcu_read_lock(); 1327 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX); 1328 if (ret < 0) { 1329 rcu_read_unlock(); 1330 goto done; 1331 } 1332 rcu_read_unlock(); 1333 1334 /* 1335 * Continues from above, so we don't need an KERN_ level 1336 */ 1337 printk(KERN_CONT " as a result of limit of %s\n", memcg_name); 1338done: 1339 1340 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n", 1341 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10, 1342 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10, 1343 res_counter_read_u64(&memcg->res, RES_FAILCNT)); 1344 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, " 1345 "failcnt %llu\n", 1346 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10, 1347 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10, 1348 res_counter_read_u64(&memcg->memsw, RES_FAILCNT)); 1349} 1350 1351/* 1352 * This function returns the number of memcg under hierarchy tree. Returns 1353 * 1(self count) if no children. 1354 */ 1355static int mem_cgroup_count_children(struct mem_cgroup *mem) 1356{ 1357 int num = 0; 1358 struct mem_cgroup *iter; 1359 1360 for_each_mem_cgroup_tree(iter, mem) 1361 num++; 1362 return num; 1363} 1364 1365/* 1366 * Return the memory (and swap, if configured) limit for a memcg. 1367 */ 1368u64 mem_cgroup_get_limit(struct mem_cgroup *memcg) 1369{ 1370 u64 limit; 1371 u64 memsw; 1372 1373 limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 1374 limit += total_swap_pages << PAGE_SHIFT; 1375 1376 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 1377 /* 1378 * If memsw is finite and limits the amount of swap space available 1379 * to this memcg, return that limit. 1380 */ 1381 return min(limit, memsw); 1382} 1383 1384/* 1385 * Visit the first child (need not be the first child as per the ordering 1386 * of the cgroup list, since we track last_scanned_child) of @mem and use 1387 * that to reclaim free pages from. 1388 */ 1389static struct mem_cgroup * 1390mem_cgroup_select_victim(struct mem_cgroup *root_mem) 1391{ 1392 struct mem_cgroup *ret = NULL; 1393 struct cgroup_subsys_state *css; 1394 int nextid, found; 1395 1396 if (!root_mem->use_hierarchy) { 1397 css_get(&root_mem->css); 1398 ret = root_mem; 1399 } 1400 1401 while (!ret) { 1402 rcu_read_lock(); 1403 nextid = root_mem->last_scanned_child + 1; 1404 css = css_get_next(&mem_cgroup_subsys, nextid, &root_mem->css, 1405 &found); 1406 if (css && css_tryget(css)) 1407 ret = container_of(css, struct mem_cgroup, css); 1408 1409 rcu_read_unlock(); 1410 /* Updates scanning parameter */ 1411 if (!css) { 1412 /* this means start scan from ID:1 */ 1413 root_mem->last_scanned_child = 0; 1414 } else 1415 root_mem->last_scanned_child = found; 1416 } 1417 1418 return ret; 1419} 1420 1421/* 1422 * Scan the hierarchy if needed to reclaim memory. We remember the last child 1423 * we reclaimed from, so that we don't end up penalizing one child extensively 1424 * based on its position in the children list. 1425 * 1426 * root_mem is the original ancestor that we've been reclaim from. 1427 * 1428 * We give up and return to the caller when we visit root_mem twice. 1429 * (other groups can be removed while we're walking....) 1430 * 1431 * If shrink==true, for avoiding to free too much, this returns immedieately. 1432 */ 1433static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, 1434 struct zone *zone, 1435 gfp_t gfp_mask, 1436 unsigned long reclaim_options) 1437{ 1438 struct mem_cgroup *victim; 1439 int ret, total = 0; 1440 int loop = 0; 1441 bool noswap = reclaim_options & MEM_CGROUP_RECLAIM_NOSWAP; 1442 bool shrink = reclaim_options & MEM_CGROUP_RECLAIM_SHRINK; 1443 bool check_soft = reclaim_options & MEM_CGROUP_RECLAIM_SOFT; 1444 unsigned long excess; 1445 1446 excess = res_counter_soft_limit_excess(&root_mem->res) >> PAGE_SHIFT; 1447 1448 /* If memsw_is_minimum==1, swap-out is of-no-use. */ 1449 if (root_mem->memsw_is_minimum) 1450 noswap = true; 1451 1452 while (1) { 1453 victim = mem_cgroup_select_victim(root_mem); 1454 if (victim == root_mem) { 1455 loop++; 1456 if (loop >= 1) 1457 drain_all_stock_async(); 1458 if (loop >= 2) { 1459 /* 1460 * If we have not been able to reclaim 1461 * anything, it might because there are 1462 * no reclaimable pages under this hierarchy 1463 */ 1464 if (!check_soft || !total) { 1465 css_put(&victim->css); 1466 break; 1467 } 1468 /* 1469 * We want to do more targeted reclaim. 1470 * excess >> 2 is not to excessive so as to 1471 * reclaim too much, nor too less that we keep 1472 * coming back to reclaim from this cgroup 1473 */ 1474 if (total >= (excess >> 2) || 1475 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS)) { 1476 css_put(&victim->css); 1477 break; 1478 } 1479 } 1480 } 1481 if (!mem_cgroup_local_usage(victim)) { 1482 /* this cgroup's local usage == 0 */ 1483 css_put(&victim->css); 1484 continue; 1485 } 1486 /* we use swappiness of local cgroup */ 1487 if (check_soft) 1488 ret = mem_cgroup_shrink_node_zone(victim, gfp_mask, 1489 noswap, get_swappiness(victim), zone); 1490 else 1491 ret = try_to_free_mem_cgroup_pages(victim, gfp_mask, 1492 noswap, get_swappiness(victim)); 1493 css_put(&victim->css); 1494 /* 1495 * At shrinking usage, we can't check we should stop here or 1496 * reclaim more. It's depends on callers. last_scanned_child 1497 * will work enough for keeping fairness under tree. 1498 */ 1499 if (shrink) 1500 return ret; 1501 total += ret; 1502 if (check_soft) { 1503 if (!res_counter_soft_limit_excess(&root_mem->res)) 1504 return total; 1505 } else if (mem_cgroup_margin(root_mem)) 1506 return 1 + total; 1507 } 1508 return total; 1509} 1510 1511/* 1512 * Check OOM-Killer is already running under our hierarchy. 1513 * If someone is running, return false. 1514 */ 1515static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) 1516{ 1517 int x, lock_count = 0; 1518 struct mem_cgroup *iter; 1519 1520 for_each_mem_cgroup_tree(iter, mem) { 1521 x = atomic_inc_return(&iter->oom_lock); 1522 lock_count = max(x, lock_count); 1523 } 1524 1525 if (lock_count == 1) 1526 return true; 1527 return false; 1528} 1529 1530static int mem_cgroup_oom_unlock(struct mem_cgroup *mem) 1531{ 1532 struct mem_cgroup *iter; 1533 1534 /* 1535 * When a new child is created while the hierarchy is under oom, 1536 * mem_cgroup_oom_lock() may not be called. We have to use 1537 * atomic_add_unless() here. 1538 */ 1539 for_each_mem_cgroup_tree(iter, mem) 1540 atomic_add_unless(&iter->oom_lock, -1, 0); 1541 return 0; 1542} 1543 1544 1545static DEFINE_MUTEX(memcg_oom_mutex); 1546static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); 1547 1548struct oom_wait_info { 1549 struct mem_cgroup *mem; 1550 wait_queue_t wait; 1551}; 1552 1553static int memcg_oom_wake_function(wait_queue_t *wait, 1554 unsigned mode, int sync, void *arg) 1555{ 1556 struct mem_cgroup *wake_mem = (struct mem_cgroup *)arg; 1557 struct oom_wait_info *oom_wait_info; 1558 1559 oom_wait_info = container_of(wait, struct oom_wait_info, wait); 1560 1561 if (oom_wait_info->mem == wake_mem) 1562 goto wakeup; 1563 /* if no hierarchy, no match */ 1564 if (!oom_wait_info->mem->use_hierarchy || !wake_mem->use_hierarchy) 1565 return 0; 1566 /* 1567 * Both of oom_wait_info->mem and wake_mem are stable under us. 1568 * Then we can use css_is_ancestor without taking care of RCU. 1569 */ 1570 if (!css_is_ancestor(&oom_wait_info->mem->css, &wake_mem->css) && 1571 !css_is_ancestor(&wake_mem->css, &oom_wait_info->mem->css)) 1572 return 0; 1573 1574wakeup: 1575 return autoremove_wake_function(wait, mode, sync, arg); 1576} 1577 1578static void memcg_wakeup_oom(struct mem_cgroup *mem) 1579{ 1580 /* for filtering, pass "mem" as argument. */ 1581 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, mem); 1582} 1583 1584static void memcg_oom_recover(struct mem_cgroup *mem) 1585{ 1586 if (mem && atomic_read(&mem->oom_lock)) 1587 memcg_wakeup_oom(mem); 1588} 1589 1590/* 1591 * try to call OOM killer. returns false if we should exit memory-reclaim loop. 1592 */ 1593bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) 1594{ 1595 struct oom_wait_info owait; 1596 bool locked, need_to_kill; 1597 1598 owait.mem = mem; 1599 owait.wait.flags = 0; 1600 owait.wait.func = memcg_oom_wake_function; 1601 owait.wait.private = current; 1602 INIT_LIST_HEAD(&owait.wait.task_list); 1603 need_to_kill = true; 1604 /* At first, try to OOM lock hierarchy under mem.*/ 1605 mutex_lock(&memcg_oom_mutex); 1606 locked = mem_cgroup_oom_lock(mem); 1607 /* 1608 * Even if signal_pending(), we can't quit charge() loop without 1609 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL 1610 * under OOM is always welcomed, use TASK_KILLABLE here. 1611 */ 1612 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE); 1613 if (!locked || mem->oom_kill_disable) 1614 need_to_kill = false; 1615 if (locked) 1616 mem_cgroup_oom_notify(mem); 1617 mutex_unlock(&memcg_oom_mutex); 1618 1619 if (need_to_kill) { 1620 finish_wait(&memcg_oom_waitq, &owait.wait); 1621 mem_cgroup_out_of_memory(mem, mask); 1622 } else { 1623 schedule(); 1624 finish_wait(&memcg_oom_waitq, &owait.wait); 1625 } 1626 mutex_lock(&memcg_oom_mutex); 1627 mem_cgroup_oom_unlock(mem); 1628 memcg_wakeup_oom(mem); 1629 mutex_unlock(&memcg_oom_mutex); 1630 1631 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) 1632 return false; 1633 /* Give chance to dying process */ 1634 schedule_timeout(1); 1635 return true; 1636} 1637 1638/* 1639 * Currently used to update mapped file statistics, but the routine can be 1640 * generalized to update other statistics as well. 1641 * 1642 * Notes: Race condition 1643 * 1644 * We usually use page_cgroup_lock() for accessing page_cgroup member but 1645 * it tends to be costly. But considering some conditions, we doesn't need 1646 * to do so _always_. 1647 * 1648 * Considering "charge", lock_page_cgroup() is not required because all 1649 * file-stat operations happen after a page is attached to radix-tree. There 1650 * are no race with "charge". 1651 * 1652 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup 1653 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even 1654 * if there are race with "uncharge". Statistics itself is properly handled 1655 * by flags. 1656 * 1657 * Considering "move", this is an only case we see a race. To make the race 1658 * small, we check MEM_CGROUP_ON_MOVE percpu value and detect there are 1659 * possibility of race condition. If there is, we take a lock. 1660 */ 1661 1662void mem_cgroup_update_page_stat(struct page *page, 1663 enum mem_cgroup_page_stat_item idx, int val) 1664{ 1665 struct mem_cgroup *mem; 1666 struct page_cgroup *pc = lookup_page_cgroup(page); 1667 bool need_unlock = false; 1668 unsigned long uninitialized_var(flags); 1669 1670 if (unlikely(!pc)) 1671 return; 1672 1673 rcu_read_lock(); 1674 mem = pc->mem_cgroup; 1675 if (unlikely(!mem || !PageCgroupUsed(pc))) 1676 goto out; 1677 /* pc->mem_cgroup is unstable ? */ 1678 if (unlikely(mem_cgroup_stealed(mem)) || PageTransHuge(page)) { 1679 /* take a lock against to access pc->mem_cgroup */ 1680 move_lock_page_cgroup(pc, &flags); 1681 need_unlock = true; 1682 mem = pc->mem_cgroup; 1683 if (!mem || !PageCgroupUsed(pc)) 1684 goto out; 1685 } 1686 1687 switch (idx) { 1688 case MEMCG_NR_FILE_MAPPED: 1689 if (val > 0) 1690 SetPageCgroupFileMapped(pc); 1691 else if (!page_mapped(page)) 1692 ClearPageCgroupFileMapped(pc); 1693 idx = MEM_CGROUP_STAT_FILE_MAPPED; 1694 break; 1695 default: 1696 BUG(); 1697 } 1698 1699 this_cpu_add(mem->stat->count[idx], val); 1700 1701out: 1702 if (unlikely(need_unlock)) 1703 move_unlock_page_cgroup(pc, &flags); 1704 rcu_read_unlock(); 1705 return; 1706} 1707EXPORT_SYMBOL(mem_cgroup_update_page_stat); 1708 1709/* 1710 * size of first charge trial. "32" comes from vmscan.c's magic value. 1711 * TODO: maybe necessary to use big numbers in big irons. 1712 */ 1713#define CHARGE_BATCH 32U 1714struct memcg_stock_pcp { 1715 struct mem_cgroup *cached; /* this never be root cgroup */ 1716 unsigned int nr_pages; 1717 struct work_struct work; 1718}; 1719static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock); 1720static atomic_t memcg_drain_count; 1721 1722/* 1723 * Try to consume stocked charge on this cpu. If success, one page is consumed 1724 * from local stock and true is returned. If the stock is 0 or charges from a 1725 * cgroup which is not current target, returns false. This stock will be 1726 * refilled. 1727 */ 1728static bool consume_stock(struct mem_cgroup *mem) 1729{ 1730 struct memcg_stock_pcp *stock; 1731 bool ret = true; 1732 1733 stock = &get_cpu_var(memcg_stock); 1734 if (mem == stock->cached && stock->nr_pages) 1735 stock->nr_pages--; 1736 else /* need to call res_counter_charge */ 1737 ret = false; 1738 put_cpu_var(memcg_stock); 1739 return ret; 1740} 1741 1742/* 1743 * Returns stocks cached in percpu to res_counter and reset cached information. 1744 */ 1745static void drain_stock(struct memcg_stock_pcp *stock) 1746{ 1747 struct mem_cgroup *old = stock->cached; 1748 1749 if (stock->nr_pages) { 1750 unsigned long bytes = stock->nr_pages * PAGE_SIZE; 1751 1752 res_counter_uncharge(&old->res, bytes); 1753 if (do_swap_account) 1754 res_counter_uncharge(&old->memsw, bytes); 1755 stock->nr_pages = 0; 1756 } 1757 stock->cached = NULL; 1758} 1759 1760/* 1761 * This must be called under preempt disabled or must be called by 1762 * a thread which is pinned to local cpu. 1763 */ 1764static void drain_local_stock(struct work_struct *dummy) 1765{ 1766 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock); 1767 drain_stock(stock); 1768} 1769 1770/* 1771 * Cache charges(val) which is from res_counter, to local per_cpu area. 1772 * This will be consumed by consume_stock() function, later. 1773 */ 1774static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages) 1775{ 1776 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock); 1777 1778 if (stock->cached != mem) { /* reset if necessary */ 1779 drain_stock(stock); 1780 stock->cached = mem; 1781 } 1782 stock->nr_pages += nr_pages; 1783 put_cpu_var(memcg_stock); 1784} 1785 1786/* 1787 * Tries to drain stocked charges in other cpus. This function is asynchronous 1788 * and just put a work per cpu for draining localy on each cpu. Caller can 1789 * expects some charges will be back to res_counter later but cannot wait for 1790 * it. 1791 */ 1792static void drain_all_stock_async(void) 1793{ 1794 int cpu; 1795 /* This function is for scheduling "drain" in asynchronous way. 1796 * The result of "drain" is not directly handled by callers. Then, 1797 * if someone is calling drain, we don't have to call drain more. 1798 * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if 1799 * there is a race. We just do loose check here. 1800 */ 1801 if (atomic_read(&memcg_drain_count)) 1802 return; 1803 /* Notify other cpus that system-wide "drain" is running */ 1804 atomic_inc(&memcg_drain_count); 1805 get_online_cpus(); 1806 for_each_online_cpu(cpu) { 1807 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); 1808 schedule_work_on(cpu, &stock->work); 1809 } 1810 put_online_cpus(); 1811 atomic_dec(&memcg_drain_count); 1812 /* We don't wait for flush_work */ 1813} 1814 1815/* This is a synchronous drain interface. */ 1816static void drain_all_stock_sync(void) 1817{ 1818 /* called when force_empty is called */ 1819 atomic_inc(&memcg_drain_count); 1820 schedule_on_each_cpu(drain_local_stock); 1821 atomic_dec(&memcg_drain_count); 1822} 1823 1824/* 1825 * This function drains percpu counter value from DEAD cpu and 1826 * move it to local cpu. Note that this function can be preempted. 1827 */ 1828static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *mem, int cpu) 1829{ 1830 int i; 1831 1832 spin_lock(&mem->pcp_counter_lock); 1833 for (i = 0; i < MEM_CGROUP_STAT_DATA; i++) { 1834 long x = per_cpu(mem->stat->count[i], cpu); 1835 1836 per_cpu(mem->stat->count[i], cpu) = 0; 1837 mem->nocpu_base.count[i] += x; 1838 } 1839 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) { 1840 unsigned long x = per_cpu(mem->stat->events[i], cpu); 1841 1842 per_cpu(mem->stat->events[i], cpu) = 0; 1843 mem->nocpu_base.events[i] += x; 1844 } 1845 /* need to clear ON_MOVE value, works as a kind of lock. */ 1846 per_cpu(mem->stat->count[MEM_CGROUP_ON_MOVE], cpu) = 0; 1847 spin_unlock(&mem->pcp_counter_lock); 1848} 1849 1850static void synchronize_mem_cgroup_on_move(struct mem_cgroup *mem, int cpu) 1851{ 1852 int idx = MEM_CGROUP_ON_MOVE; 1853 1854 spin_lock(&mem->pcp_counter_lock); 1855 per_cpu(mem->stat->count[idx], cpu) = mem->nocpu_base.count[idx]; 1856 spin_unlock(&mem->pcp_counter_lock); 1857} 1858 1859static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb, 1860 unsigned long action, 1861 void *hcpu) 1862{ 1863 int cpu = (unsigned long)hcpu; 1864 struct memcg_stock_pcp *stock; 1865 struct mem_cgroup *iter; 1866 1867 if ((action == CPU_ONLINE)) { 1868 for_each_mem_cgroup_all(iter) 1869 synchronize_mem_cgroup_on_move(iter, cpu); 1870 return NOTIFY_OK; 1871 } 1872 1873 if ((action != CPU_DEAD) || action != CPU_DEAD_FROZEN) 1874 return NOTIFY_OK; 1875 1876 for_each_mem_cgroup_all(iter) 1877 mem_cgroup_drain_pcp_counter(iter, cpu); 1878 1879 stock = &per_cpu(memcg_stock, cpu); 1880 drain_stock(stock); 1881 return NOTIFY_OK; 1882} 1883 1884 1885/* See __mem_cgroup_try_charge() for details */ 1886enum { 1887 CHARGE_OK, /* success */ 1888 CHARGE_RETRY, /* need to retry but retry is not bad */ 1889 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */ 1890 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */ 1891 CHARGE_OOM_DIE, /* the current is killed because of OOM */ 1892}; 1893 1894static int mem_cgroup_do_charge(struct mem_cgroup *mem, gfp_t gfp_mask, 1895 unsigned int nr_pages, bool oom_check) 1896{ 1897 unsigned long csize = nr_pages * PAGE_SIZE; 1898 struct mem_cgroup *mem_over_limit; 1899 struct res_counter *fail_res; 1900 unsigned long flags = 0; 1901 int ret; 1902 1903 ret = res_counter_charge(&mem->res, csize, &fail_res); 1904 1905 if (likely(!ret)) { 1906 if (!do_swap_account) 1907 return CHARGE_OK; 1908 ret = res_counter_charge(&mem->memsw, csize, &fail_res); 1909 if (likely(!ret)) 1910 return CHARGE_OK; 1911 1912 res_counter_uncharge(&mem->res, csize); 1913 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw); 1914 flags |= MEM_CGROUP_RECLAIM_NOSWAP; 1915 } else 1916 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res); 1917 /* 1918 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch 1919 * of regular pages (CHARGE_BATCH), or a single regular page (1). 1920 * 1921 * Never reclaim on behalf of optional batching, retry with a 1922 * single page instead. 1923 */ 1924 if (nr_pages == CHARGE_BATCH) 1925 return CHARGE_RETRY; 1926 1927 if (!(gfp_mask & __GFP_WAIT)) 1928 return CHARGE_WOULDBLOCK; 1929 1930 ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, 1931 gfp_mask, flags); 1932 if (mem_cgroup_margin(mem_over_limit) >= nr_pages) 1933 return CHARGE_RETRY; 1934 /* 1935 * Even though the limit is exceeded at this point, reclaim 1936 * may have been able to free some pages. Retry the charge 1937 * before killing the task. 1938 * 1939 * Only for regular pages, though: huge pages are rather 1940 * unlikely to succeed so close to the limit, and we fall back 1941 * to regular pages anyway in case of failure. 1942 */ 1943 if (nr_pages == 1 && ret) 1944 return CHARGE_RETRY; 1945 1946 /* 1947 * At task move, charge accounts can be doubly counted. So, it's 1948 * better to wait until the end of task_move if something is going on. 1949 */ 1950 if (mem_cgroup_wait_acct_move(mem_over_limit)) 1951 return CHARGE_RETRY; 1952 1953 /* If we don't need to call oom-killer at el, return immediately */ 1954 if (!oom_check) 1955 return CHARGE_NOMEM; 1956 /* check OOM */ 1957 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask)) 1958 return CHARGE_OOM_DIE; 1959 1960 return CHARGE_RETRY; 1961} 1962 1963/* 1964 * Unlike exported interface, "oom" parameter is added. if oom==true, 1965 * oom-killer can be invoked. 1966 */ 1967static int __mem_cgroup_try_charge(struct mm_struct *mm, 1968 gfp_t gfp_mask, 1969 unsigned int nr_pages, 1970 struct mem_cgroup **memcg, 1971 bool oom) 1972{ 1973 unsigned int batch = max(CHARGE_BATCH, nr_pages); 1974 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 1975 struct mem_cgroup *mem = NULL; 1976 int ret; 1977 1978 /* 1979 * Unlike gloval-vm's OOM-kill, we're not in memory shortage 1980 * in system level. So, allow to go ahead dying process in addition to 1981 * MEMDIE process. 1982 */ 1983 if (unlikely(test_thread_flag(TIF_MEMDIE) 1984 || fatal_signal_pending(current))) 1985 goto bypass; 1986 1987 /* 1988 * We always charge the cgroup the mm_struct belongs to. 1989 * The mm_struct's mem_cgroup changes on task migration if the 1990 * thread group leader migrates. It's possible that mm is not 1991 * set, if so charge the init_mm (happens for pagecache usage). 1992 */ 1993 if (!*memcg && !mm) 1994 goto bypass; 1995again: 1996 if (*memcg) { /* css should be a valid one */ 1997 mem = *memcg; 1998 VM_BUG_ON(css_is_removed(&mem->css)); 1999 if (mem_cgroup_is_root(mem)) 2000 goto done; 2001 if (nr_pages == 1 && consume_stock(mem)) 2002 goto done; 2003 css_get(&mem->css); 2004 } else { 2005 struct task_struct *p; 2006 2007 rcu_read_lock(); 2008 p = rcu_dereference(mm->owner); 2009 /* 2010 * Because we don't have task_lock(), "p" can exit. 2011 * In that case, "mem" can point to root or p can be NULL with 2012 * race with swapoff. Then, we have small risk of mis-accouning. 2013 * But such kind of mis-account by race always happens because 2014 * we don't have cgroup_mutex(). It's overkill and we allo that 2015 * small race, here. 2016 * (*) swapoff at el will charge against mm-struct not against 2017 * task-struct. So, mm->owner can be NULL. 2018 */ 2019 mem = mem_cgroup_from_task(p); 2020 if (!mem || mem_cgroup_is_root(mem)) { 2021 rcu_read_unlock(); 2022 goto done; 2023 } 2024 if (nr_pages == 1 && consume_stock(mem)) { 2025 /* 2026 * It seems dagerous to access memcg without css_get(). 2027 * But considering how consume_stok works, it's not 2028 * necessary. If consume_stock success, some charges 2029 * from this memcg are cached on this cpu. So, we 2030 * don't need to call css_get()/css_tryget() before 2031 * calling consume_stock(). 2032 */ 2033 rcu_read_unlock(); 2034 goto done; 2035 } 2036 /* after here, we may be blocked. we need to get refcnt */ 2037 if (!css_tryget(&mem->css)) { 2038 rcu_read_unlock(); 2039 goto again; 2040 } 2041 rcu_read_unlock(); 2042 } 2043 2044 do { 2045 bool oom_check; 2046 2047 /* If killed, bypass charge */ 2048 if (fatal_signal_pending(current)) { 2049 css_put(&mem->css); 2050 goto bypass; 2051 } 2052 2053 oom_check = false; 2054 if (oom && !nr_oom_retries) { 2055 oom_check = true; 2056 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES; 2057 } 2058 2059 ret = mem_cgroup_do_charge(mem, gfp_mask, batch, oom_check); 2060 switch (ret) { 2061 case CHARGE_OK: 2062 break; 2063 case CHARGE_RETRY: /* not in OOM situation but retry */ 2064 batch = nr_pages; 2065 css_put(&mem->css); 2066 mem = NULL; 2067 goto again; 2068 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */ 2069 css_put(&mem->css); 2070 goto nomem; 2071 case CHARGE_NOMEM: /* OOM routine works */ 2072 if (!oom) { 2073 css_put(&mem->css); 2074 goto nomem; 2075 } 2076 /* If oom, we never return -ENOMEM */ 2077 nr_oom_retries--; 2078 break; 2079 case CHARGE_OOM_DIE: /* Killed by OOM Killer */ 2080 css_put(&mem->css); 2081 goto bypass; 2082 } 2083 } while (ret != CHARGE_OK); 2084 2085 if (batch > nr_pages) 2086 refill_stock(mem, batch - nr_pages); 2087 css_put(&mem->css); 2088done: 2089 *memcg = mem; 2090 return 0; 2091nomem: 2092 *memcg = NULL; 2093 return -ENOMEM; 2094bypass: 2095 *memcg = NULL; 2096 return 0; 2097} 2098 2099/* 2100 * Somemtimes we have to undo a charge we got by try_charge(). 2101 * This function is for that and do uncharge, put css's refcnt. 2102 * gotten by try_charge(). 2103 */ 2104static void __mem_cgroup_cancel_charge(struct mem_cgroup *mem, 2105 unsigned int nr_pages) 2106{ 2107 if (!mem_cgroup_is_root(mem)) { 2108 unsigned long bytes = nr_pages * PAGE_SIZE; 2109 2110 res_counter_uncharge(&mem->res, bytes); 2111 if (do_swap_account) 2112 res_counter_uncharge(&mem->memsw, bytes); 2113 } 2114} 2115 2116/* 2117 * A helper function to get mem_cgroup from ID. must be called under 2118 * rcu_read_lock(). The caller must check css_is_removed() or some if 2119 * it's concern. (dropping refcnt from swap can be called against removed 2120 * memcg.) 2121 */ 2122static struct mem_cgroup *mem_cgroup_lookup(unsigned short id) 2123{ 2124 struct cgroup_subsys_state *css; 2125 2126 /* ID 0 is unused ID */ 2127 if (!id) 2128 return NULL; 2129 css = css_lookup(&mem_cgroup_subsys, id); 2130 if (!css) 2131 return NULL; 2132 return container_of(css, struct mem_cgroup, css); 2133} 2134 2135struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page) 2136{ 2137 struct mem_cgroup *mem = NULL; 2138 struct page_cgroup *pc; 2139 unsigned short id; 2140 swp_entry_t ent; 2141 2142 VM_BUG_ON(!PageLocked(page)); 2143 2144 pc = lookup_page_cgroup(page); 2145 lock_page_cgroup(pc); 2146 if (PageCgroupUsed(pc)) { 2147 mem = pc->mem_cgroup; 2148 if (mem && !css_tryget(&mem->css)) 2149 mem = NULL; 2150 } else if (PageSwapCache(page)) { 2151 ent.val = page_private(page); 2152 id = lookup_swap_cgroup(ent); 2153 rcu_read_lock(); 2154 mem = mem_cgroup_lookup(id); 2155 if (mem && !css_tryget(&mem->css)) 2156 mem = NULL; 2157 rcu_read_unlock(); 2158 } 2159 unlock_page_cgroup(pc); 2160 return mem; 2161} 2162 2163static void __mem_cgroup_commit_charge(struct mem_cgroup *mem, 2164 struct page *page, 2165 unsigned int nr_pages, 2166 struct page_cgroup *pc, 2167 enum charge_type ctype) 2168{ 2169 lock_page_cgroup(pc); 2170 if (unlikely(PageCgroupUsed(pc))) { 2171 unlock_page_cgroup(pc); 2172 __mem_cgroup_cancel_charge(mem, nr_pages); 2173 return; 2174 } 2175 /* 2176 * we don't need page_cgroup_lock about tail pages, becase they are not 2177 * accessed by any other context at this point. 2178 */ 2179 pc->mem_cgroup = mem; 2180 /* 2181 * We access a page_cgroup asynchronously without lock_page_cgroup(). 2182 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup 2183 * is accessed after testing USED bit. To make pc->mem_cgroup visible 2184 * before USED bit, we need memory barrier here. 2185 * See mem_cgroup_add_lru_list(), etc. 2186 */ 2187 smp_wmb(); 2188 switch (ctype) { 2189 case MEM_CGROUP_CHARGE_TYPE_CACHE: 2190 case MEM_CGROUP_CHARGE_TYPE_SHMEM: 2191 SetPageCgroupCache(pc); 2192 SetPageCgroupUsed(pc); 2193 break; 2194 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 2195 ClearPageCgroupCache(pc); 2196 SetPageCgroupUsed(pc); 2197 break; 2198 default: 2199 break; 2200 } 2201 2202 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), nr_pages); 2203 unlock_page_cgroup(pc); 2204 /* 2205 * "charge_statistics" updated event counter. Then, check it. 2206 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree. 2207 * if they exceeds softlimit. 2208 */ 2209 memcg_check_events(mem, page); 2210} 2211 2212#ifdef CONFIG_TRANSPARENT_HUGEPAGE 2213 2214#define PCGF_NOCOPY_AT_SPLIT ((1 << PCG_LOCK) | (1 << PCG_MOVE_LOCK) |\ 2215 (1 << PCG_ACCT_LRU) | (1 << PCG_MIGRATION)) 2216/* 2217 * Because tail pages are not marked as "used", set it. We're under 2218 * zone->lru_lock, 'splitting on pmd' and compund_lock. 2219 */ 2220void mem_cgroup_split_huge_fixup(struct page *head, struct page *tail) 2221{ 2222 struct page_cgroup *head_pc = lookup_page_cgroup(head); 2223 struct page_cgroup *tail_pc = lookup_page_cgroup(tail); 2224 unsigned long flags; 2225 2226 if (mem_cgroup_disabled()) 2227 return; 2228 /* 2229 * We have no races with charge/uncharge but will have races with 2230 * page state accounting. 2231 */ 2232 move_lock_page_cgroup(head_pc, &flags); 2233 2234 tail_pc->mem_cgroup = head_pc->mem_cgroup; 2235 smp_wmb(); /* see __commit_charge() */ 2236 if (PageCgroupAcctLRU(head_pc)) { 2237 enum lru_list lru; 2238 struct mem_cgroup_per_zone *mz; 2239 2240 /* 2241 * LRU flags cannot be copied because we need to add tail 2242 *.page to LRU by generic call and our hook will be called. 2243 * We hold lru_lock, then, reduce counter directly. 2244 */ 2245 lru = page_lru(head); 2246 mz = page_cgroup_zoneinfo(head_pc->mem_cgroup, head); 2247 MEM_CGROUP_ZSTAT(mz, lru) -= 1; 2248 } 2249 tail_pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT; 2250 move_unlock_page_cgroup(head_pc, &flags); 2251} 2252#endif 2253 2254/** 2255 * mem_cgroup_move_account - move account of the page 2256 * @page: the page 2257 * @nr_pages: number of regular pages (>1 for huge pages) 2258 * @pc: page_cgroup of the page. 2259 * @from: mem_cgroup which the page is moved from. 2260 * @to: mem_cgroup which the page is moved to. @from != @to. 2261 * @uncharge: whether we should call uncharge and css_put against @from. 2262 * 2263 * The caller must confirm following. 2264 * - page is not on LRU (isolate_page() is useful.) 2265 * - compound_lock is held when nr_pages > 1 2266 * 2267 * This function doesn't do "charge" nor css_get to new cgroup. It should be 2268 * done by a caller(__mem_cgroup_try_charge would be useful). If @uncharge is 2269 * true, this function does "uncharge" from old cgroup, but it doesn't if 2270 * @uncharge is false, so a caller should do "uncharge". 2271 */ 2272static int mem_cgroup_move_account(struct page *page, 2273 unsigned int nr_pages, 2274 struct page_cgroup *pc, 2275 struct mem_cgroup *from, 2276 struct mem_cgroup *to, 2277 bool uncharge) 2278{ 2279 unsigned long flags; 2280 int ret; 2281 2282 VM_BUG_ON(from == to); 2283 VM_BUG_ON(PageLRU(page)); 2284 /* 2285 * The page is isolated from LRU. So, collapse function 2286 * will not handle this page. But page splitting can happen. 2287 * Do this check under compound_page_lock(). The caller should 2288 * hold it. 2289 */ 2290 ret = -EBUSY; 2291 if (nr_pages > 1 && !PageTransHuge(page)) 2292 goto out; 2293 2294 lock_page_cgroup(pc); 2295 2296 ret = -EINVAL; 2297 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from) 2298 goto unlock; 2299 2300 move_lock_page_cgroup(pc, &flags); 2301 2302 if (PageCgroupFileMapped(pc)) { 2303 /* Update mapped_file data for mem_cgroup */ 2304 preempt_disable(); 2305 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 2306 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]); 2307 preempt_enable(); 2308 } 2309 mem_cgroup_charge_statistics(from, PageCgroupCache(pc), -nr_pages); 2310 if (uncharge) 2311 /* This is not "cancel", but cancel_charge does all we need. */ 2312 __mem_cgroup_cancel_charge(from, nr_pages); 2313 2314 /* caller should have done css_get */ 2315 pc->mem_cgroup = to; 2316 mem_cgroup_charge_statistics(to, PageCgroupCache(pc), nr_pages); 2317 /* 2318 * We charges against "to" which may not have any tasks. Then, "to" 2319 * can be under rmdir(). But in current implementation, caller of 2320 * this function is just force_empty() and move charge, so it's 2321 * guaranteed that "to" is never removed. So, we don't check rmdir 2322 * status here. 2323 */ 2324 move_unlock_page_cgroup(pc, &flags); 2325 ret = 0; 2326unlock: 2327 unlock_page_cgroup(pc); 2328 /* 2329 * check events 2330 */ 2331 memcg_check_events(to, page); 2332 memcg_check_events(from, page); 2333out: 2334 return ret; 2335} 2336 2337/* 2338 * move charges to its parent. 2339 */ 2340 2341static int mem_cgroup_move_parent(struct page *page, 2342 struct page_cgroup *pc, 2343 struct mem_cgroup *child, 2344 gfp_t gfp_mask) 2345{ 2346 struct cgroup *cg = child->css.cgroup; 2347 struct cgroup *pcg = cg->parent; 2348 struct mem_cgroup *parent; 2349 unsigned int nr_pages; 2350 unsigned long uninitialized_var(flags); 2351 int ret; 2352 2353 /* Is ROOT ? */ 2354 if (!pcg) 2355 return -EINVAL; 2356 2357 ret = -EBUSY; 2358 if (!get_page_unless_zero(page)) 2359 goto out; 2360 if (isolate_lru_page(page)) 2361 goto put; 2362 2363 nr_pages = hpage_nr_pages(page); 2364 2365 parent = mem_cgroup_from_cont(pcg); 2366 ret = __mem_cgroup_try_charge(NULL, gfp_mask, nr_pages, &parent, false); 2367 if (ret || !parent) 2368 goto put_back; 2369 2370 if (nr_pages > 1) 2371 flags = compound_lock_irqsave(page); 2372 2373 ret = mem_cgroup_move_account(page, nr_pages, pc, child, parent, true); 2374 if (ret) 2375 __mem_cgroup_cancel_charge(parent, nr_pages); 2376 2377 if (nr_pages > 1) 2378 compound_unlock_irqrestore(page, flags); 2379put_back: 2380 putback_lru_page(page); 2381put: 2382 put_page(page); 2383out: 2384 return ret; 2385} 2386 2387/* 2388 * Charge the memory controller for page usage. 2389 * Return 2390 * 0 if the charge was successful 2391 * < 0 if the cgroup is over its limit 2392 */ 2393static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm, 2394 gfp_t gfp_mask, enum charge_type ctype) 2395{ 2396 struct mem_cgroup *mem = NULL; 2397 unsigned int nr_pages = 1; 2398 struct page_cgroup *pc; 2399 bool oom = true; 2400 int ret; 2401 2402 if (PageTransHuge(page)) { 2403 nr_pages <<= compound_order(page); 2404 VM_BUG_ON(!PageTransHuge(page)); 2405 /* 2406 * Never OOM-kill a process for a huge page. The 2407 * fault handler will fall back to regular pages. 2408 */ 2409 oom = false; 2410 } 2411 2412 pc = lookup_page_cgroup(page); 2413 BUG_ON(!pc); /* XXX: remove this and move pc lookup into commit */ 2414 2415 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &mem, oom); 2416 if (ret || !mem) 2417 return ret; 2418 2419 __mem_cgroup_commit_charge(mem, page, nr_pages, pc, ctype); 2420 return 0; 2421} 2422 2423int mem_cgroup_newpage_charge(struct page *page, 2424 struct mm_struct *mm, gfp_t gfp_mask) 2425{ 2426 if (mem_cgroup_disabled()) 2427 return 0; 2428 /* 2429 * If already mapped, we don't have to account. 2430 * If page cache, page->mapping has address_space. 2431 * But page->mapping may have out-of-use anon_vma pointer, 2432 * detecit it by PageAnon() check. newly-mapped-anon's page->mapping 2433 * is NULL. 2434 */ 2435 if (page_mapped(page) || (page->mapping && !PageAnon(page))) 2436 return 0; 2437 if (unlikely(!mm)) 2438 mm = &init_mm; 2439 return mem_cgroup_charge_common(page, mm, gfp_mask, 2440 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2441} 2442 2443static void 2444__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2445 enum charge_type ctype); 2446 2447static void 2448__mem_cgroup_commit_charge_lrucare(struct page *page, struct mem_cgroup *mem, 2449 enum charge_type ctype) 2450{ 2451 struct page_cgroup *pc = lookup_page_cgroup(page); 2452 /* 2453 * In some case, SwapCache, FUSE(splice_buf->radixtree), the page 2454 * is already on LRU. It means the page may on some other page_cgroup's 2455 * LRU. Take care of it. 2456 */ 2457 mem_cgroup_lru_del_before_commit(page); 2458 __mem_cgroup_commit_charge(mem, page, 1, pc, ctype); 2459 mem_cgroup_lru_add_after_commit(page); 2460 return; 2461} 2462 2463int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm, 2464 gfp_t gfp_mask) 2465{ 2466 struct mem_cgroup *mem = NULL; 2467 int ret; 2468 2469 if (mem_cgroup_disabled()) 2470 return 0; 2471 if (PageCompound(page)) 2472 return 0; 2473 /* 2474 * Corner case handling. This is called from add_to_page_cache() 2475 * in usual. But some FS (shmem) precharges this page before calling it 2476 * and call add_to_page_cache() with GFP_NOWAIT. 2477 * 2478 * For GFP_NOWAIT case, the page may be pre-charged before calling 2479 * add_to_page_cache(). (See shmem.c) check it here and avoid to call 2480 * charge twice. (It works but has to pay a bit larger cost.) 2481 * And when the page is SwapCache, it should take swap information 2482 * into account. This is under lock_page() now. 2483 */ 2484 if (!(gfp_mask & __GFP_WAIT)) { 2485 struct page_cgroup *pc; 2486 2487 pc = lookup_page_cgroup(page); 2488 if (!pc) 2489 return 0; 2490 lock_page_cgroup(pc); 2491 if (PageCgroupUsed(pc)) { 2492 unlock_page_cgroup(pc); 2493 return 0; 2494 } 2495 unlock_page_cgroup(pc); 2496 } 2497 2498 if (unlikely(!mm)) 2499 mm = &init_mm; 2500 2501 if (page_is_file_cache(page)) { 2502 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, &mem, true); 2503 if (ret || !mem) 2504 return ret; 2505 2506 /* 2507 * FUSE reuses pages without going through the final 2508 * put that would remove them from the LRU list, make 2509 * sure that they get relinked properly. 2510 */ 2511 __mem_cgroup_commit_charge_lrucare(page, mem, 2512 MEM_CGROUP_CHARGE_TYPE_CACHE); 2513 return ret; 2514 } 2515 /* shmem */ 2516 if (PageSwapCache(page)) { 2517 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); 2518 if (!ret) 2519 __mem_cgroup_commit_charge_swapin(page, mem, 2520 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2521 } else 2522 ret = mem_cgroup_charge_common(page, mm, gfp_mask, 2523 MEM_CGROUP_CHARGE_TYPE_SHMEM); 2524 2525 return ret; 2526} 2527 2528/* 2529 * While swap-in, try_charge -> commit or cancel, the page is locked. 2530 * And when try_charge() successfully returns, one refcnt to memcg without 2531 * struct page_cgroup is acquired. This refcnt will be consumed by 2532 * "commit()" or removed by "cancel()" 2533 */ 2534int mem_cgroup_try_charge_swapin(struct mm_struct *mm, 2535 struct page *page, 2536 gfp_t mask, struct mem_cgroup **ptr) 2537{ 2538 struct mem_cgroup *mem; 2539 int ret; 2540 2541 *ptr = NULL; 2542 2543 if (mem_cgroup_disabled()) 2544 return 0; 2545 2546 if (!do_swap_account) 2547 goto charge_cur_mm; 2548 /* 2549 * A racing thread's fault, or swapoff, may have already updated 2550 * the pte, and even removed page from swap cache: in those cases 2551 * do_swap_page()'s pte_same() test will fail; but there's also a 2552 * KSM case which does need to charge the page. 2553 */ 2554 if (!PageSwapCache(page)) 2555 goto charge_cur_mm; 2556 mem = try_get_mem_cgroup_from_page(page); 2557 if (!mem) 2558 goto charge_cur_mm; 2559 *ptr = mem; 2560 ret = __mem_cgroup_try_charge(NULL, mask, 1, ptr, true); 2561 css_put(&mem->css); 2562 return ret; 2563charge_cur_mm: 2564 if (unlikely(!mm)) 2565 mm = &init_mm; 2566 return __mem_cgroup_try_charge(mm, mask, 1, ptr, true); 2567} 2568 2569static void 2570__mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr, 2571 enum charge_type ctype) 2572{ 2573 if (mem_cgroup_disabled()) 2574 return; 2575 if (!ptr) 2576 return; 2577 cgroup_exclude_rmdir(&ptr->css); 2578 2579 __mem_cgroup_commit_charge_lrucare(page, ptr, ctype); 2580 /* 2581 * Now swap is on-memory. This means this page may be 2582 * counted both as mem and swap....double count. 2583 * Fix it by uncharging from memsw. Basically, this SwapCache is stable 2584 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page() 2585 * may call delete_from_swap_cache() before reach here. 2586 */ 2587 if (do_swap_account && PageSwapCache(page)) { 2588 swp_entry_t ent = {.val = page_private(page)}; 2589 unsigned short id; 2590 struct mem_cgroup *memcg; 2591 2592 id = swap_cgroup_record(ent, 0); 2593 rcu_read_lock(); 2594 memcg = mem_cgroup_lookup(id); 2595 if (memcg) { 2596 /* 2597 * This recorded memcg can be obsolete one. So, avoid 2598 * calling css_tryget 2599 */ 2600 if (!mem_cgroup_is_root(memcg)) 2601 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 2602 mem_cgroup_swap_statistics(memcg, false); 2603 mem_cgroup_put(memcg); 2604 } 2605 rcu_read_unlock(); 2606 } 2607 /* 2608 * At swapin, we may charge account against cgroup which has no tasks. 2609 * So, rmdir()->pre_destroy() can be called while we do this charge. 2610 * In that case, we need to call pre_destroy() again. check it here. 2611 */ 2612 cgroup_release_and_wakeup_rmdir(&ptr->css); 2613} 2614 2615void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr) 2616{ 2617 __mem_cgroup_commit_charge_swapin(page, ptr, 2618 MEM_CGROUP_CHARGE_TYPE_MAPPED); 2619} 2620 2621void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *mem) 2622{ 2623 if (mem_cgroup_disabled()) 2624 return; 2625 if (!mem) 2626 return; 2627 __mem_cgroup_cancel_charge(mem, 1); 2628} 2629 2630static void mem_cgroup_do_uncharge(struct mem_cgroup *mem, 2631 unsigned int nr_pages, 2632 const enum charge_type ctype) 2633{ 2634 struct memcg_batch_info *batch = NULL; 2635 bool uncharge_memsw = true; 2636 2637 /* If swapout, usage of swap doesn't decrease */ 2638 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) 2639 uncharge_memsw = false; 2640 2641 batch = ¤t->memcg_batch; 2642 /* 2643 * In usual, we do css_get() when we remember memcg pointer. 2644 * But in this case, we keep res->usage until end of a series of 2645 * uncharges. Then, it's ok to ignore memcg's refcnt. 2646 */ 2647 if (!batch->memcg) 2648 batch->memcg = mem; 2649 /* 2650 * do_batch > 0 when unmapping pages or inode invalidate/truncate. 2651 * In those cases, all pages freed continuously can be expected to be in 2652 * the same cgroup and we have chance to coalesce uncharges. 2653 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE) 2654 * because we want to do uncharge as soon as possible. 2655 */ 2656 2657 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE)) 2658 goto direct_uncharge; 2659 2660 if (nr_pages > 1) 2661 goto direct_uncharge; 2662 2663 /* 2664 * In typical case, batch->memcg == mem. This means we can 2665 * merge a series of uncharges to an uncharge of res_counter. 2666 * If not, we uncharge res_counter ony by one. 2667 */ 2668 if (batch->memcg != mem) 2669 goto direct_uncharge; 2670 /* remember freed charge and uncharge it later */ 2671 batch->nr_pages++; 2672 if (uncharge_memsw) 2673 batch->memsw_nr_pages++; 2674 return; 2675direct_uncharge: 2676 res_counter_uncharge(&mem->res, nr_pages * PAGE_SIZE); 2677 if (uncharge_memsw) 2678 res_counter_uncharge(&mem->memsw, nr_pages * PAGE_SIZE); 2679 if (unlikely(batch->memcg != mem)) 2680 memcg_oom_recover(mem); 2681 return; 2682} 2683 2684/* 2685 * uncharge if !page_mapped(page) 2686 */ 2687static struct mem_cgroup * 2688__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype) 2689{ 2690 struct mem_cgroup *mem = NULL; 2691 unsigned int nr_pages = 1; 2692 struct page_cgroup *pc; 2693 2694 if (mem_cgroup_disabled()) 2695 return NULL; 2696 2697 if (PageSwapCache(page)) 2698 return NULL; 2699 2700 if (PageTransHuge(page)) { 2701 nr_pages <<= compound_order(page); 2702 VM_BUG_ON(!PageTransHuge(page)); 2703 } 2704 /* 2705 * Check if our page_cgroup is valid 2706 */ 2707 pc = lookup_page_cgroup(page); 2708 if (unlikely(!pc || !PageCgroupUsed(pc))) 2709 return NULL; 2710 2711 lock_page_cgroup(pc); 2712 2713 mem = pc->mem_cgroup; 2714 2715 if (!PageCgroupUsed(pc)) 2716 goto unlock_out; 2717 2718 switch (ctype) { 2719 case MEM_CGROUP_CHARGE_TYPE_MAPPED: 2720 case MEM_CGROUP_CHARGE_TYPE_DROP: 2721 /* See mem_cgroup_prepare_migration() */ 2722 if (page_mapped(page) || PageCgroupMigration(pc)) 2723 goto unlock_out; 2724 break; 2725 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT: 2726 if (!PageAnon(page)) { /* Shared memory */ 2727 if (page->mapping && !page_is_file_cache(page)) 2728 goto unlock_out; 2729 } else if (page_mapped(page)) /* Anon */ 2730 goto unlock_out; 2731 break; 2732 default: 2733 break; 2734 } 2735 2736 mem_cgroup_charge_statistics(mem, PageCgroupCache(pc), -nr_pages); 2737 2738 ClearPageCgroupUsed(pc); 2739 /* 2740 * pc->mem_cgroup is not cleared here. It will be accessed when it's 2741 * freed from LRU. This is safe because uncharged page is expected not 2742 * to be reused (freed soon). Exception is SwapCache, it's handled by 2743 * special functions. 2744 */ 2745 2746 unlock_page_cgroup(pc); 2747 /* 2748 * even after unlock, we have mem->res.usage here and this memcg 2749 * will never be freed. 2750 */ 2751 memcg_check_events(mem, page); 2752 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) { 2753 mem_cgroup_swap_statistics(mem, true); 2754 mem_cgroup_get(mem); 2755 } 2756 if (!mem_cgroup_is_root(mem)) 2757 mem_cgroup_do_uncharge(mem, nr_pages, ctype); 2758 2759 return mem; 2760 2761unlock_out: 2762 unlock_page_cgroup(pc); 2763 return NULL; 2764} 2765 2766void mem_cgroup_uncharge_page(struct page *page) 2767{ 2768 /* early check. */ 2769 if (page_mapped(page)) 2770 return; 2771 if (page->mapping && !PageAnon(page)) 2772 return; 2773 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED); 2774} 2775 2776void mem_cgroup_uncharge_cache_page(struct page *page) 2777{ 2778 VM_BUG_ON(page_mapped(page)); 2779 VM_BUG_ON(page->mapping); 2780 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE); 2781} 2782 2783/* 2784 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate. 2785 * In that cases, pages are freed continuously and we can expect pages 2786 * are in the same memcg. All these calls itself limits the number of 2787 * pages freed at once, then uncharge_start/end() is called properly. 2788 * This may be called prural(2) times in a context, 2789 */ 2790 2791void mem_cgroup_uncharge_start(void) 2792{ 2793 current->memcg_batch.do_batch++; 2794 /* We can do nest. */ 2795 if (current->memcg_batch.do_batch == 1) { 2796 current->memcg_batch.memcg = NULL; 2797 current->memcg_batch.nr_pages = 0; 2798 current->memcg_batch.memsw_nr_pages = 0; 2799 } 2800} 2801 2802void mem_cgroup_uncharge_end(void) 2803{ 2804 struct memcg_batch_info *batch = ¤t->memcg_batch; 2805 2806 if (!batch->do_batch) 2807 return; 2808 2809 batch->do_batch--; 2810 if (batch->do_batch) /* If stacked, do nothing. */ 2811 return; 2812 2813 if (!batch->memcg) 2814 return; 2815 /* 2816 * This "batch->memcg" is valid without any css_get/put etc... 2817 * bacause we hide charges behind us. 2818 */ 2819 if (batch->nr_pages) 2820 res_counter_uncharge(&batch->memcg->res, 2821 batch->nr_pages * PAGE_SIZE); 2822 if (batch->memsw_nr_pages) 2823 res_counter_uncharge(&batch->memcg->memsw, 2824 batch->memsw_nr_pages * PAGE_SIZE); 2825 memcg_oom_recover(batch->memcg); 2826 /* forget this pointer (for sanity check) */ 2827 batch->memcg = NULL; 2828} 2829 2830#ifdef CONFIG_SWAP 2831/* 2832 * called after __delete_from_swap_cache() and drop "page" account. 2833 * memcg information is recorded to swap_cgroup of "ent" 2834 */ 2835void 2836mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout) 2837{ 2838 struct mem_cgroup *memcg; 2839 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT; 2840 2841 if (!swapout) /* this was a swap cache but the swap is unused ! */ 2842 ctype = MEM_CGROUP_CHARGE_TYPE_DROP; 2843 2844 memcg = __mem_cgroup_uncharge_common(page, ctype); 2845 2846 /* 2847 * record memcg information, if swapout && memcg != NULL, 2848 * mem_cgroup_get() was called in uncharge(). 2849 */ 2850 if (do_swap_account && swapout && memcg) 2851 swap_cgroup_record(ent, css_id(&memcg->css)); 2852} 2853#endif 2854 2855#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 2856/* 2857 * called from swap_entry_free(). remove record in swap_cgroup and 2858 * uncharge "memsw" account. 2859 */ 2860void mem_cgroup_uncharge_swap(swp_entry_t ent) 2861{ 2862 struct mem_cgroup *memcg; 2863 unsigned short id; 2864 2865 if (!do_swap_account) 2866 return; 2867 2868 id = swap_cgroup_record(ent, 0); 2869 rcu_read_lock(); 2870 memcg = mem_cgroup_lookup(id); 2871 if (memcg) { 2872 /* 2873 * We uncharge this because swap is freed. 2874 * This memcg can be obsolete one. We avoid calling css_tryget 2875 */ 2876 if (!mem_cgroup_is_root(memcg)) 2877 res_counter_uncharge(&memcg->memsw, PAGE_SIZE); 2878 mem_cgroup_swap_statistics(memcg, false); 2879 mem_cgroup_put(memcg); 2880 } 2881 rcu_read_unlock(); 2882} 2883 2884/** 2885 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. 2886 * @entry: swap entry to be moved 2887 * @from: mem_cgroup which the entry is moved from 2888 * @to: mem_cgroup which the entry is moved to 2889 * @need_fixup: whether we should fixup res_counters and refcounts. 2890 * 2891 * It succeeds only when the swap_cgroup's record for this entry is the same 2892 * as the mem_cgroup's id of @from. 2893 * 2894 * Returns 0 on success, -EINVAL on failure. 2895 * 2896 * The caller must have charged to @to, IOW, called res_counter_charge() about 2897 * both res and memsw, and called css_get(). 2898 */ 2899static int mem_cgroup_move_swap_account(swp_entry_t entry, 2900 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 2901{ 2902 unsigned short old_id, new_id; 2903 2904 old_id = css_id(&from->css); 2905 new_id = css_id(&to->css); 2906 2907 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) { 2908 mem_cgroup_swap_statistics(from, false); 2909 mem_cgroup_swap_statistics(to, true); 2910 /* 2911 * This function is only called from task migration context now. 2912 * It postpones res_counter and refcount handling till the end 2913 * of task migration(mem_cgroup_clear_mc()) for performance 2914 * improvement. But we cannot postpone mem_cgroup_get(to) 2915 * because if the process that has been moved to @to does 2916 * swap-in, the refcount of @to might be decreased to 0. 2917 */ 2918 mem_cgroup_get(to); 2919 if (need_fixup) { 2920 if (!mem_cgroup_is_root(from)) 2921 res_counter_uncharge(&from->memsw, PAGE_SIZE); 2922 mem_cgroup_put(from); 2923 /* 2924 * we charged both to->res and to->memsw, so we should 2925 * uncharge to->res. 2926 */ 2927 if (!mem_cgroup_is_root(to)) 2928 res_counter_uncharge(&to->res, PAGE_SIZE); 2929 } 2930 return 0; 2931 } 2932 return -EINVAL; 2933} 2934#else 2935static inline int mem_cgroup_move_swap_account(swp_entry_t entry, 2936 struct mem_cgroup *from, struct mem_cgroup *to, bool need_fixup) 2937{ 2938 return -EINVAL; 2939} 2940#endif 2941 2942/* 2943 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old 2944 * page belongs to. 2945 */ 2946int mem_cgroup_prepare_migration(struct page *page, 2947 struct page *newpage, struct mem_cgroup **ptr, gfp_t gfp_mask) 2948{ 2949 struct mem_cgroup *mem = NULL; 2950 struct page_cgroup *pc; 2951 enum charge_type ctype; 2952 int ret = 0; 2953 2954 *ptr = NULL; 2955 2956 VM_BUG_ON(PageTransHuge(page)); 2957 if (mem_cgroup_disabled()) 2958 return 0; 2959 2960 pc = lookup_page_cgroup(page); 2961 lock_page_cgroup(pc); 2962 if (PageCgroupUsed(pc)) { 2963 mem = pc->mem_cgroup; 2964 css_get(&mem->css); 2965 /* 2966 * At migrating an anonymous page, its mapcount goes down 2967 * to 0 and uncharge() will be called. But, even if it's fully 2968 * unmapped, migration may fail and this page has to be 2969 * charged again. We set MIGRATION flag here and delay uncharge 2970 * until end_migration() is called 2971 * 2972 * Corner Case Thinking 2973 * A) 2974 * When the old page was mapped as Anon and it's unmap-and-freed 2975 * while migration was ongoing. 2976 * If unmap finds the old page, uncharge() of it will be delayed 2977 * until end_migration(). If unmap finds a new page, it's 2978 * uncharged when it make mapcount to be 1->0. If unmap code 2979 * finds swap_migration_entry, the new page will not be mapped 2980 * and end_migration() will find it(mapcount==0). 2981 * 2982 * B) 2983 * When the old page was mapped but migraion fails, the kernel 2984 * remaps it. A charge for it is kept by MIGRATION flag even 2985 * if mapcount goes down to 0. We can do remap successfully 2986 * without charging it again. 2987 * 2988 * C) 2989 * The "old" page is under lock_page() until the end of 2990 * migration, so, the old page itself will not be swapped-out. 2991 * If the new page is swapped out before end_migraton, our 2992 * hook to usual swap-out path will catch the event. 2993 */ 2994 if (PageAnon(page)) 2995 SetPageCgroupMigration(pc); 2996 } 2997 unlock_page_cgroup(pc); 2998 /* 2999 * If the page is not charged at this point, 3000 * we return here. 3001 */ 3002 if (!mem) 3003 return 0; 3004 3005 *ptr = mem; 3006 ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, ptr, false); 3007 css_put(&mem->css);/* drop extra refcnt */ 3008 if (ret || *ptr == NULL) { 3009 if (PageAnon(page)) { 3010 lock_page_cgroup(pc); 3011 ClearPageCgroupMigration(pc); 3012 unlock_page_cgroup(pc); 3013 /* 3014 * The old page may be fully unmapped while we kept it. 3015 */ 3016 mem_cgroup_uncharge_page(page); 3017 } 3018 return -ENOMEM; 3019 } 3020 /* 3021 * We charge new page before it's used/mapped. So, even if unlock_page() 3022 * is called before end_migration, we can catch all events on this new 3023 * page. In the case new page is migrated but not remapped, new page's 3024 * mapcount will be finally 0 and we call uncharge in end_migration(). 3025 */ 3026 pc = lookup_page_cgroup(newpage); 3027 if (PageAnon(page)) 3028 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED; 3029 else if (page_is_file_cache(page)) 3030 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE; 3031 else 3032 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM; 3033 __mem_cgroup_commit_charge(mem, page, 1, pc, ctype); 3034 return ret; 3035} 3036 3037/* remove redundant charge if migration failed*/ 3038void mem_cgroup_end_migration(struct mem_cgroup *mem, 3039 struct page *oldpage, struct page *newpage, bool migration_ok) 3040{ 3041 struct page *used, *unused; 3042 struct page_cgroup *pc; 3043 3044 if (!mem) 3045 return; 3046 /* blocks rmdir() */ 3047 cgroup_exclude_rmdir(&mem->css); 3048 if (!migration_ok) { 3049 used = oldpage; 3050 unused = newpage; 3051 } else { 3052 used = newpage; 3053 unused = oldpage; 3054 } 3055 /* 3056 * We disallowed uncharge of pages under migration because mapcount 3057 * of the page goes down to zero, temporarly. 3058 * Clear the flag and check the page should be charged. 3059 */ 3060 pc = lookup_page_cgroup(oldpage); 3061 lock_page_cgroup(pc); 3062 ClearPageCgroupMigration(pc); 3063 unlock_page_cgroup(pc); 3064 3065 __mem_cgroup_uncharge_common(unused, MEM_CGROUP_CHARGE_TYPE_FORCE); 3066 3067 /* 3068 * If a page is a file cache, radix-tree replacement is very atomic 3069 * and we can skip this check. When it was an Anon page, its mapcount 3070 * goes down to 0. But because we added MIGRATION flage, it's not 3071 * uncharged yet. There are several case but page->mapcount check 3072 * and USED bit check in mem_cgroup_uncharge_page() will do enough 3073 * check. (see prepare_charge() also) 3074 */ 3075 if (PageAnon(used)) 3076 mem_cgroup_uncharge_page(used); 3077 /* 3078 * At migration, we may charge account against cgroup which has no 3079 * tasks. 3080 * So, rmdir()->pre_destroy() can be called while we do this charge. 3081 * In that case, we need to call pre_destroy() again. check it here. 3082 */ 3083 cgroup_release_and_wakeup_rmdir(&mem->css); 3084} 3085 3086/* 3087 * A call to try to shrink memory usage on charge failure at shmem's swapin. 3088 * Calling hierarchical_reclaim is not enough because we should update 3089 * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM. 3090 * Moreover considering hierarchy, we should reclaim from the mem_over_limit, 3091 * not from the memcg which this page would be charged to. 3092 * try_charge_swapin does all of these works properly. 3093 */ 3094int mem_cgroup_shmem_charge_fallback(struct page *page, 3095 struct mm_struct *mm, 3096 gfp_t gfp_mask) 3097{ 3098 struct mem_cgroup *mem; 3099 int ret; 3100 3101 if (mem_cgroup_disabled()) 3102 return 0; 3103 3104 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem); 3105 if (!ret) 3106 mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */ 3107 3108 return ret; 3109} 3110 3111#ifdef CONFIG_DEBUG_VM 3112static struct page_cgroup *lookup_page_cgroup_used(struct page *page) 3113{ 3114 struct page_cgroup *pc; 3115 3116 pc = lookup_page_cgroup(page); 3117 if (likely(pc) && PageCgroupUsed(pc)) 3118 return pc; 3119 return NULL; 3120} 3121 3122bool mem_cgroup_bad_page_check(struct page *page) 3123{ 3124 if (mem_cgroup_disabled()) 3125 return false; 3126 3127 return lookup_page_cgroup_used(page) != NULL; 3128} 3129 3130void mem_cgroup_print_bad_page(struct page *page) 3131{ 3132 struct page_cgroup *pc; 3133 3134 pc = lookup_page_cgroup_used(page); 3135 if (pc) { 3136 int ret = -1; 3137 char *path; 3138 3139 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p", 3140 pc, pc->flags, pc->mem_cgroup); 3141 3142 path = kmalloc(PATH_MAX, GFP_KERNEL); 3143 if (path) { 3144 rcu_read_lock(); 3145 ret = cgroup_path(pc->mem_cgroup->css.cgroup, 3146 path, PATH_MAX); 3147 rcu_read_unlock(); 3148 } 3149 3150 printk(KERN_CONT "(%s)\n", 3151 (ret < 0) ? "cannot get the path" : path); 3152 kfree(path); 3153 } 3154} 3155#endif 3156 3157static DEFINE_MUTEX(set_limit_mutex); 3158 3159static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, 3160 unsigned long long val) 3161{ 3162 int retry_count; 3163 u64 memswlimit, memlimit; 3164 int ret = 0; 3165 int children = mem_cgroup_count_children(memcg); 3166 u64 curusage, oldusage; 3167 int enlarge; 3168 3169 /* 3170 * For keeping hierarchical_reclaim simple, how long we should retry 3171 * is depends on callers. We set our retry-count to be function 3172 * of # of children which we should visit in this loop. 3173 */ 3174 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children; 3175 3176 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE); 3177 3178 enlarge = 0; 3179 while (retry_count) { 3180 if (signal_pending(current)) { 3181 ret = -EINTR; 3182 break; 3183 } 3184 /* 3185 * Rather than hide all in some function, I do this in 3186 * open coded manner. You see what this really does. 3187 * We have to guarantee mem->res.limit < mem->memsw.limit. 3188 */ 3189 mutex_lock(&set_limit_mutex); 3190 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3191 if (memswlimit < val) { 3192 ret = -EINVAL; 3193 mutex_unlock(&set_limit_mutex); 3194 break; 3195 } 3196 3197 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3198 if (memlimit < val) 3199 enlarge = 1; 3200 3201 ret = res_counter_set_limit(&memcg->res, val); 3202 if (!ret) { 3203 if (memswlimit == val) 3204 memcg->memsw_is_minimum = true; 3205 else 3206 memcg->memsw_is_minimum = false; 3207 } 3208 mutex_unlock(&set_limit_mutex); 3209 3210 if (!ret) 3211 break; 3212 3213 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 3214 MEM_CGROUP_RECLAIM_SHRINK); 3215 curusage = res_counter_read_u64(&memcg->res, RES_USAGE); 3216 /* Usage is reduced ? */ 3217 if (curusage >= oldusage) 3218 retry_count--; 3219 else 3220 oldusage = curusage; 3221 } 3222 if (!ret && enlarge) 3223 memcg_oom_recover(memcg); 3224 3225 return ret; 3226} 3227 3228static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg, 3229 unsigned long long val) 3230{ 3231 int retry_count; 3232 u64 memlimit, memswlimit, oldusage, curusage; 3233 int children = mem_cgroup_count_children(memcg); 3234 int ret = -EBUSY; 3235 int enlarge = 0; 3236 3237 /* see mem_cgroup_resize_res_limit */ 3238 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES; 3239 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 3240 while (retry_count) { 3241 if (signal_pending(current)) { 3242 ret = -EINTR; 3243 break; 3244 } 3245 /* 3246 * Rather than hide all in some function, I do this in 3247 * open coded manner. You see what this really does. 3248 * We have to guarantee mem->res.limit < mem->memsw.limit. 3249 */ 3250 mutex_lock(&set_limit_mutex); 3251 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3252 if (memlimit > val) { 3253 ret = -EINVAL; 3254 mutex_unlock(&set_limit_mutex); 3255 break; 3256 } 3257 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3258 if (memswlimit < val) 3259 enlarge = 1; 3260 ret = res_counter_set_limit(&memcg->memsw, val); 3261 if (!ret) { 3262 if (memlimit == val) 3263 memcg->memsw_is_minimum = true; 3264 else 3265 memcg->memsw_is_minimum = false; 3266 } 3267 mutex_unlock(&set_limit_mutex); 3268 3269 if (!ret) 3270 break; 3271 3272 mem_cgroup_hierarchical_reclaim(memcg, NULL, GFP_KERNEL, 3273 MEM_CGROUP_RECLAIM_NOSWAP | 3274 MEM_CGROUP_RECLAIM_SHRINK); 3275 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE); 3276 /* Usage is reduced ? */ 3277 if (curusage >= oldusage) 3278 retry_count--; 3279 else 3280 oldusage = curusage; 3281 } 3282 if (!ret && enlarge) 3283 memcg_oom_recover(memcg); 3284 return ret; 3285} 3286 3287unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order, 3288 gfp_t gfp_mask) 3289{ 3290 unsigned long nr_reclaimed = 0; 3291 struct mem_cgroup_per_zone *mz, *next_mz = NULL; 3292 unsigned long reclaimed; 3293 int loop = 0; 3294 struct mem_cgroup_tree_per_zone *mctz; 3295 unsigned long long excess; 3296 3297 if (order > 0) 3298 return 0; 3299 3300 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone)); 3301 /* 3302 * This loop can run a while, specially if mem_cgroup's continuously 3303 * keep exceeding their soft limit and putting the system under 3304 * pressure 3305 */ 3306 do { 3307 if (next_mz) 3308 mz = next_mz; 3309 else 3310 mz = mem_cgroup_largest_soft_limit_node(mctz); 3311 if (!mz) 3312 break; 3313 3314 reclaimed = mem_cgroup_hierarchical_reclaim(mz->mem, zone, 3315 gfp_mask, 3316 MEM_CGROUP_RECLAIM_SOFT); 3317 nr_reclaimed += reclaimed; 3318 spin_lock(&mctz->lock); 3319 3320 /* 3321 * If we failed to reclaim anything from this memory cgroup 3322 * it is time to move on to the next cgroup 3323 */ 3324 next_mz = NULL; 3325 if (!reclaimed) { 3326 do { 3327 /* 3328 * Loop until we find yet another one. 3329 * 3330 * By the time we get the soft_limit lock 3331 * again, someone might have aded the 3332 * group back on the RB tree. Iterate to 3333 * make sure we get a different mem. 3334 * mem_cgroup_largest_soft_limit_node returns 3335 * NULL if no other cgroup is present on 3336 * the tree 3337 */ 3338 next_mz = 3339 __mem_cgroup_largest_soft_limit_node(mctz); 3340 if (next_mz == mz) { 3341 css_put(&next_mz->mem->css); 3342 next_mz = NULL; 3343 } else /* next_mz == NULL or other memcg */ 3344 break; 3345 } while (1); 3346 } 3347 __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); 3348 excess = res_counter_soft_limit_excess(&mz->mem->res); 3349 /* 3350 * One school of thought says that we should not add 3351 * back the node to the tree if reclaim returns 0. 3352 * But our reclaim could return 0, simply because due 3353 * to priority we are exposing a smaller subset of 3354 * memory to reclaim from. Consider this as a longer 3355 * term TODO. 3356 */ 3357 /* If excess == 0, no tree ops */ 3358 __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess); 3359 spin_unlock(&mctz->lock); 3360 css_put(&mz->mem->css); 3361 loop++; 3362 /* 3363 * Could not reclaim anything and there are no more 3364 * mem cgroups to try or we seem to be looping without 3365 * reclaiming anything. 3366 */ 3367 if (!nr_reclaimed && 3368 (next_mz == NULL || 3369 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS)) 3370 break; 3371 } while (!nr_reclaimed); 3372 if (next_mz) 3373 css_put(&next_mz->mem->css); 3374 return nr_reclaimed; 3375} 3376 3377/* 3378 * This routine traverse page_cgroup in given list and drop them all. 3379 * *And* this routine doesn't reclaim page itself, just removes page_cgroup. 3380 */ 3381static int mem_cgroup_force_empty_list(struct mem_cgroup *mem, 3382 int node, int zid, enum lru_list lru) 3383{ 3384 struct zone *zone; 3385 struct mem_cgroup_per_zone *mz; 3386 struct page_cgroup *pc, *busy; 3387 unsigned long flags, loop; 3388 struct list_head *list; 3389 int ret = 0; 3390 3391 zone = &NODE_DATA(node)->node_zones[zid]; 3392 mz = mem_cgroup_zoneinfo(mem, node, zid); 3393 list = &mz->lists[lru]; 3394 3395 loop = MEM_CGROUP_ZSTAT(mz, lru); 3396 /* give some margin against EBUSY etc...*/ 3397 loop += 256; 3398 busy = NULL; 3399 while (loop--) { 3400 struct page *page; 3401 3402 ret = 0; 3403 spin_lock_irqsave(&zone->lru_lock, flags); 3404 if (list_empty(list)) { 3405 spin_unlock_irqrestore(&zone->lru_lock, flags); 3406 break; 3407 } 3408 pc = list_entry(list->prev, struct page_cgroup, lru); 3409 if (busy == pc) { 3410 list_move(&pc->lru, list); 3411 busy = NULL; 3412 spin_unlock_irqrestore(&zone->lru_lock, flags); 3413 continue; 3414 } 3415 spin_unlock_irqrestore(&zone->lru_lock, flags); 3416 3417 page = lookup_cgroup_page(pc); 3418 3419 ret = mem_cgroup_move_parent(page, pc, mem, GFP_KERNEL); 3420 if (ret == -ENOMEM) 3421 break; 3422 3423 if (ret == -EBUSY || ret == -EINVAL) { 3424 /* found lock contention or "pc" is obsolete. */ 3425 busy = pc; 3426 cond_resched(); 3427 } else 3428 busy = NULL; 3429 } 3430 3431 if (!ret && !list_empty(list)) 3432 return -EBUSY; 3433 return ret; 3434} 3435 3436/* 3437 * make mem_cgroup's charge to be 0 if there is no task. 3438 * This enables deleting this mem_cgroup. 3439 */ 3440static int mem_cgroup_force_empty(struct mem_cgroup *mem, bool free_all) 3441{ 3442 int ret; 3443 int node, zid, shrink; 3444 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES; 3445 struct cgroup *cgrp = mem->css.cgroup; 3446 3447 css_get(&mem->css); 3448 3449 shrink = 0; 3450 /* should free all ? */ 3451 if (free_all) 3452 goto try_to_free; 3453move_account: 3454 do { 3455 ret = -EBUSY; 3456 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children)) 3457 goto out; 3458 ret = -EINTR; 3459 if (signal_pending(current)) 3460 goto out; 3461 /* This is for making all *used* pages to be on LRU. */ 3462 lru_add_drain_all(); 3463 drain_all_stock_sync(); 3464 ret = 0; 3465 mem_cgroup_start_move(mem); 3466 for_each_node_state(node, N_HIGH_MEMORY) { 3467 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) { 3468 enum lru_list l; 3469 for_each_lru(l) { 3470 ret = mem_cgroup_force_empty_list(mem, 3471 node, zid, l); 3472 if (ret) 3473 break; 3474 } 3475 } 3476 if (ret) 3477 break; 3478 } 3479 mem_cgroup_end_move(mem); 3480 memcg_oom_recover(mem); 3481 /* it seems parent cgroup doesn't have enough mem */ 3482 if (ret == -ENOMEM) 3483 goto try_to_free; 3484 cond_resched(); 3485 /* "ret" should also be checked to ensure all lists are empty. */ 3486 } while (mem->res.usage > 0 || ret); 3487out: 3488 css_put(&mem->css); 3489 return ret; 3490 3491try_to_free: 3492 /* returns EBUSY if there is a task or if we come here twice. */ 3493 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) { 3494 ret = -EBUSY; 3495 goto out; 3496 } 3497 /* we call try-to-free pages for make this cgroup empty */ 3498 lru_add_drain_all(); 3499 /* try to free all pages in this cgroup */ 3500 shrink = 1; 3501 while (nr_retries && mem->res.usage > 0) { 3502 int progress; 3503 3504 if (signal_pending(current)) { 3505 ret = -EINTR; 3506 goto out; 3507 } 3508 progress = try_to_free_mem_cgroup_pages(mem, GFP_KERNEL, 3509 false, get_swappiness(mem)); 3510 if (!progress) { 3511 nr_retries--; 3512 /* maybe some writeback is necessary */ 3513 congestion_wait(BLK_RW_ASYNC, HZ/10); 3514 } 3515 3516 } 3517 lru_add_drain(); 3518 /* try move_account...there may be some *locked* pages. */ 3519 goto move_account; 3520} 3521 3522int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event) 3523{ 3524 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true); 3525} 3526 3527 3528static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft) 3529{ 3530 return mem_cgroup_from_cont(cont)->use_hierarchy; 3531} 3532 3533static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft, 3534 u64 val) 3535{ 3536 int retval = 0; 3537 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 3538 struct cgroup *parent = cont->parent; 3539 struct mem_cgroup *parent_mem = NULL; 3540 3541 if (parent) 3542 parent_mem = mem_cgroup_from_cont(parent); 3543 3544 cgroup_lock(); 3545 /* 3546 * If parent's use_hierarchy is set, we can't make any modifications 3547 * in the child subtrees. If it is unset, then the change can 3548 * occur, provided the current cgroup has no children. 3549 * 3550 * For the root cgroup, parent_mem is NULL, we allow value to be 3551 * set if there are no children. 3552 */ 3553 if ((!parent_mem || !parent_mem->use_hierarchy) && 3554 (val == 1 || val == 0)) { 3555 if (list_empty(&cont->children)) 3556 mem->use_hierarchy = val; 3557 else 3558 retval = -EBUSY; 3559 } else 3560 retval = -EINVAL; 3561 cgroup_unlock(); 3562 3563 return retval; 3564} 3565 3566 3567static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *mem, 3568 enum mem_cgroup_stat_index idx) 3569{ 3570 struct mem_cgroup *iter; 3571 long val = 0; 3572 3573 /* Per-cpu values can be negative, use a signed accumulator */ 3574 for_each_mem_cgroup_tree(iter, mem) 3575 val += mem_cgroup_read_stat(iter, idx); 3576 3577 if (val < 0) /* race ? */ 3578 val = 0; 3579 return val; 3580} 3581 3582static inline u64 mem_cgroup_usage(struct mem_cgroup *mem, bool swap) 3583{ 3584 u64 val; 3585 3586 if (!mem_cgroup_is_root(mem)) { 3587 if (!swap) 3588 return res_counter_read_u64(&mem->res, RES_USAGE); 3589 else 3590 return res_counter_read_u64(&mem->memsw, RES_USAGE); 3591 } 3592 3593 val = mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_CACHE); 3594 val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_RSS); 3595 3596 if (swap) 3597 val += mem_cgroup_recursive_stat(mem, MEM_CGROUP_STAT_SWAPOUT); 3598 3599 return val << PAGE_SHIFT; 3600} 3601 3602static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft) 3603{ 3604 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 3605 u64 val; 3606 int type, name; 3607 3608 type = MEMFILE_TYPE(cft->private); 3609 name = MEMFILE_ATTR(cft->private); 3610 switch (type) { 3611 case _MEM: 3612 if (name == RES_USAGE) 3613 val = mem_cgroup_usage(mem, false); 3614 else 3615 val = res_counter_read_u64(&mem->res, name); 3616 break; 3617 case _MEMSWAP: 3618 if (name == RES_USAGE) 3619 val = mem_cgroup_usage(mem, true); 3620 else 3621 val = res_counter_read_u64(&mem->memsw, name); 3622 break; 3623 default: 3624 BUG(); 3625 break; 3626 } 3627 return val; 3628} 3629/* 3630 * The user of this function is... 3631 * RES_LIMIT. 3632 */ 3633static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft, 3634 const char *buffer) 3635{ 3636 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); 3637 int type, name; 3638 unsigned long long val; 3639 int ret; 3640 3641 type = MEMFILE_TYPE(cft->private); 3642 name = MEMFILE_ATTR(cft->private); 3643 switch (name) { 3644 case RES_LIMIT: 3645 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */ 3646 ret = -EINVAL; 3647 break; 3648 } 3649 /* This function does all necessary parse...reuse it */ 3650 ret = res_counter_memparse_write_strategy(buffer, &val); 3651 if (ret) 3652 break; 3653 if (type == _MEM) 3654 ret = mem_cgroup_resize_limit(memcg, val); 3655 else 3656 ret = mem_cgroup_resize_memsw_limit(memcg, val); 3657 break; 3658 case RES_SOFT_LIMIT: 3659 ret = res_counter_memparse_write_strategy(buffer, &val); 3660 if (ret) 3661 break; 3662 /* 3663 * For memsw, soft limits are hard to implement in terms 3664 * of semantics, for now, we support soft limits for 3665 * control without swap 3666 */ 3667 if (type == _MEM) 3668 ret = res_counter_set_soft_limit(&memcg->res, val); 3669 else 3670 ret = -EINVAL; 3671 break; 3672 default: 3673 ret = -EINVAL; /* should be BUG() ? */ 3674 break; 3675 } 3676 return ret; 3677} 3678 3679static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg, 3680 unsigned long long *mem_limit, unsigned long long *memsw_limit) 3681{ 3682 struct cgroup *cgroup; 3683 unsigned long long min_limit, min_memsw_limit, tmp; 3684 3685 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT); 3686 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3687 cgroup = memcg->css.cgroup; 3688 if (!memcg->use_hierarchy) 3689 goto out; 3690 3691 while (cgroup->parent) { 3692 cgroup = cgroup->parent; 3693 memcg = mem_cgroup_from_cont(cgroup); 3694 if (!memcg->use_hierarchy) 3695 break; 3696 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT); 3697 min_limit = min(min_limit, tmp); 3698 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT); 3699 min_memsw_limit = min(min_memsw_limit, tmp); 3700 } 3701out: 3702 *mem_limit = min_limit; 3703 *memsw_limit = min_memsw_limit; 3704 return; 3705} 3706 3707static int mem_cgroup_reset(struct cgroup *cont, unsigned int event) 3708{ 3709 struct mem_cgroup *mem; 3710 int type, name; 3711 3712 mem = mem_cgroup_from_cont(cont); 3713 type = MEMFILE_TYPE(event); 3714 name = MEMFILE_ATTR(event); 3715 switch (name) { 3716 case RES_MAX_USAGE: 3717 if (type == _MEM) 3718 res_counter_reset_max(&mem->res); 3719 else 3720 res_counter_reset_max(&mem->memsw); 3721 break; 3722 case RES_FAILCNT: 3723 if (type == _MEM) 3724 res_counter_reset_failcnt(&mem->res); 3725 else 3726 res_counter_reset_failcnt(&mem->memsw); 3727 break; 3728 } 3729 3730 return 0; 3731} 3732 3733static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp, 3734 struct cftype *cft) 3735{ 3736 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate; 3737} 3738 3739#ifdef CONFIG_MMU 3740static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 3741 struct cftype *cft, u64 val) 3742{ 3743 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 3744 3745 if (val >= (1 << NR_MOVE_TYPE)) 3746 return -EINVAL; 3747 /* 3748 * We check this value several times in both in can_attach() and 3749 * attach(), so we need cgroup lock to prevent this value from being 3750 * inconsistent. 3751 */ 3752 cgroup_lock(); 3753 mem->move_charge_at_immigrate = val; 3754 cgroup_unlock(); 3755 3756 return 0; 3757} 3758#else 3759static int mem_cgroup_move_charge_write(struct cgroup *cgrp, 3760 struct cftype *cft, u64 val) 3761{ 3762 return -ENOSYS; 3763} 3764#endif 3765 3766 3767/* For read statistics */ 3768enum { 3769 MCS_CACHE, 3770 MCS_RSS, 3771 MCS_FILE_MAPPED, 3772 MCS_PGPGIN, 3773 MCS_PGPGOUT, 3774 MCS_SWAP, 3775 MCS_INACTIVE_ANON, 3776 MCS_ACTIVE_ANON, 3777 MCS_INACTIVE_FILE, 3778 MCS_ACTIVE_FILE, 3779 MCS_UNEVICTABLE, 3780 NR_MCS_STAT, 3781}; 3782 3783struct mcs_total_stat { 3784 s64 stat[NR_MCS_STAT]; 3785}; 3786 3787struct { 3788 char *local_name; 3789 char *total_name; 3790} memcg_stat_strings[NR_MCS_STAT] = { 3791 {"cache", "total_cache"}, 3792 {"rss", "total_rss"}, 3793 {"mapped_file", "total_mapped_file"}, 3794 {"pgpgin", "total_pgpgin"}, 3795 {"pgpgout", "total_pgpgout"}, 3796 {"swap", "total_swap"}, 3797 {"inactive_anon", "total_inactive_anon"}, 3798 {"active_anon", "total_active_anon"}, 3799 {"inactive_file", "total_inactive_file"}, 3800 {"active_file", "total_active_file"}, 3801 {"unevictable", "total_unevictable"} 3802}; 3803 3804 3805static void 3806mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) 3807{ 3808 s64 val; 3809 3810 /* per cpu stat */ 3811 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_CACHE); 3812 s->stat[MCS_CACHE] += val * PAGE_SIZE; 3813 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_RSS); 3814 s->stat[MCS_RSS] += val * PAGE_SIZE; 3815 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_MAPPED); 3816 s->stat[MCS_FILE_MAPPED] += val * PAGE_SIZE; 3817 val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGIN); 3818 s->stat[MCS_PGPGIN] += val; 3819 val = mem_cgroup_read_events(mem, MEM_CGROUP_EVENTS_PGPGOUT); 3820 s->stat[MCS_PGPGOUT] += val; 3821 if (do_swap_account) { 3822 val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_SWAPOUT); 3823 s->stat[MCS_SWAP] += val * PAGE_SIZE; 3824 } 3825 3826 /* per zone stat */ 3827 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON); 3828 s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE; 3829 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_ANON); 3830 s->stat[MCS_ACTIVE_ANON] += val * PAGE_SIZE; 3831 val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_FILE); 3832 s->stat[MCS_INACTIVE_FILE] += val * PAGE_SIZE; 3833 val = mem_cgroup_get_local_zonestat(mem, LRU_ACTIVE_FILE); 3834 s->stat[MCS_ACTIVE_FILE] += val * PAGE_SIZE; 3835 val = mem_cgroup_get_local_zonestat(mem, LRU_UNEVICTABLE); 3836 s->stat[MCS_UNEVICTABLE] += val * PAGE_SIZE; 3837} 3838 3839static void 3840mem_cgroup_get_total_stat(struct mem_cgroup *mem, struct mcs_total_stat *s) 3841{ 3842 struct mem_cgroup *iter; 3843 3844 for_each_mem_cgroup_tree(iter, mem) 3845 mem_cgroup_get_local_stat(iter, s); 3846} 3847 3848static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft, 3849 struct cgroup_map_cb *cb) 3850{ 3851 struct mem_cgroup *mem_cont = mem_cgroup_from_cont(cont); 3852 struct mcs_total_stat mystat; 3853 int i; 3854 3855 memset(&mystat, 0, sizeof(mystat)); 3856 mem_cgroup_get_local_stat(mem_cont, &mystat); 3857 3858 for (i = 0; i < NR_MCS_STAT; i++) { 3859 if (i == MCS_SWAP && !do_swap_account) 3860 continue; 3861 cb->fill(cb, memcg_stat_strings[i].local_name, mystat.stat[i]); 3862 } 3863 3864 /* Hierarchical information */ 3865 { 3866 unsigned long long limit, memsw_limit; 3867 memcg_get_hierarchical_limit(mem_cont, &limit, &memsw_limit); 3868 cb->fill(cb, "hierarchical_memory_limit", limit); 3869 if (do_swap_account) 3870 cb->fill(cb, "hierarchical_memsw_limit", memsw_limit); 3871 } 3872 3873 memset(&mystat, 0, sizeof(mystat)); 3874 mem_cgroup_get_total_stat(mem_cont, &mystat); 3875 for (i = 0; i < NR_MCS_STAT; i++) { 3876 if (i == MCS_SWAP && !do_swap_account) 3877 continue; 3878 cb->fill(cb, memcg_stat_strings[i].total_name, mystat.stat[i]); 3879 } 3880 3881#ifdef CONFIG_DEBUG_VM 3882 cb->fill(cb, "inactive_ratio", calc_inactive_ratio(mem_cont, NULL)); 3883 3884 { 3885 int nid, zid; 3886 struct mem_cgroup_per_zone *mz; 3887 unsigned long recent_rotated[2] = {0, 0}; 3888 unsigned long recent_scanned[2] = {0, 0}; 3889 3890 for_each_online_node(nid) 3891 for (zid = 0; zid < MAX_NR_ZONES; zid++) { 3892 mz = mem_cgroup_zoneinfo(mem_cont, nid, zid); 3893 3894 recent_rotated[0] += 3895 mz->reclaim_stat.recent_rotated[0]; 3896 recent_rotated[1] += 3897 mz->reclaim_stat.recent_rotated[1]; 3898 recent_scanned[0] += 3899 mz->reclaim_stat.recent_scanned[0]; 3900 recent_scanned[1] += 3901 mz->reclaim_stat.recent_scanned[1]; 3902 } 3903 cb->fill(cb, "recent_rotated_anon", recent_rotated[0]); 3904 cb->fill(cb, "recent_rotated_file", recent_rotated[1]); 3905 cb->fill(cb, "recent_scanned_anon", recent_scanned[0]); 3906 cb->fill(cb, "recent_scanned_file", recent_scanned[1]); 3907 } 3908#endif 3909 3910 return 0; 3911} 3912 3913static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft) 3914{ 3915 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3916 3917 return get_swappiness(memcg); 3918} 3919 3920static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft, 3921 u64 val) 3922{ 3923 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 3924 struct mem_cgroup *parent; 3925 3926 if (val > 100) 3927 return -EINVAL; 3928 3929 if (cgrp->parent == NULL) 3930 return -EINVAL; 3931 3932 parent = mem_cgroup_from_cont(cgrp->parent); 3933 3934 cgroup_lock(); 3935 3936 /* If under hierarchy, only empty-root can set this value */ 3937 if ((parent->use_hierarchy) || 3938 (memcg->use_hierarchy && !list_empty(&cgrp->children))) { 3939 cgroup_unlock(); 3940 return -EINVAL; 3941 } 3942 3943 memcg->swappiness = val; 3944 3945 cgroup_unlock(); 3946 3947 return 0; 3948} 3949 3950static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap) 3951{ 3952 struct mem_cgroup_threshold_ary *t; 3953 u64 usage; 3954 int i; 3955 3956 rcu_read_lock(); 3957 if (!swap) 3958 t = rcu_dereference(memcg->thresholds.primary); 3959 else 3960 t = rcu_dereference(memcg->memsw_thresholds.primary); 3961 3962 if (!t) 3963 goto unlock; 3964 3965 usage = mem_cgroup_usage(memcg, swap); 3966 3967 /* 3968 * current_threshold points to threshold just below usage. 3969 * If it's not true, a threshold was crossed after last 3970 * call of __mem_cgroup_threshold(). 3971 */ 3972 i = t->current_threshold; 3973 3974 /* 3975 * Iterate backward over array of thresholds starting from 3976 * current_threshold and check if a threshold is crossed. 3977 * If none of thresholds below usage is crossed, we read 3978 * only one element of the array here. 3979 */ 3980 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--) 3981 eventfd_signal(t->entries[i].eventfd, 1); 3982 3983 /* i = current_threshold + 1 */ 3984 i++; 3985 3986 /* 3987 * Iterate forward over array of thresholds starting from 3988 * current_threshold+1 and check if a threshold is crossed. 3989 * If none of thresholds above usage is crossed, we read 3990 * only one element of the array here. 3991 */ 3992 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++) 3993 eventfd_signal(t->entries[i].eventfd, 1); 3994 3995 /* Update current_threshold */ 3996 t->current_threshold = i - 1; 3997unlock: 3998 rcu_read_unlock(); 3999} 4000 4001static void mem_cgroup_threshold(struct mem_cgroup *memcg) 4002{ 4003 while (memcg) { 4004 __mem_cgroup_threshold(memcg, false); 4005 if (do_swap_account) 4006 __mem_cgroup_threshold(memcg, true); 4007 4008 memcg = parent_mem_cgroup(memcg); 4009 } 4010} 4011 4012static int compare_thresholds(const void *a, const void *b) 4013{ 4014 const struct mem_cgroup_threshold *_a = a; 4015 const struct mem_cgroup_threshold *_b = b; 4016 4017 return _a->threshold - _b->threshold; 4018} 4019 4020static int mem_cgroup_oom_notify_cb(struct mem_cgroup *mem) 4021{ 4022 struct mem_cgroup_eventfd_list *ev; 4023 4024 list_for_each_entry(ev, &mem->oom_notify, list) 4025 eventfd_signal(ev->eventfd, 1); 4026 return 0; 4027} 4028 4029static void mem_cgroup_oom_notify(struct mem_cgroup *mem) 4030{ 4031 struct mem_cgroup *iter; 4032 4033 for_each_mem_cgroup_tree(iter, mem) 4034 mem_cgroup_oom_notify_cb(iter); 4035} 4036 4037static int mem_cgroup_usage_register_event(struct cgroup *cgrp, 4038 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 4039{ 4040 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4041 struct mem_cgroup_thresholds *thresholds; 4042 struct mem_cgroup_threshold_ary *new; 4043 int type = MEMFILE_TYPE(cft->private); 4044 u64 threshold, usage; 4045 int i, size, ret; 4046 4047 ret = res_counter_memparse_write_strategy(args, &threshold); 4048 if (ret) 4049 return ret; 4050 4051 mutex_lock(&memcg->thresholds_lock); 4052 4053 if (type == _MEM) 4054 thresholds = &memcg->thresholds; 4055 else if (type == _MEMSWAP) 4056 thresholds = &memcg->memsw_thresholds; 4057 else 4058 BUG(); 4059 4060 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 4061 4062 /* Check if a threshold crossed before adding a new one */ 4063 if (thresholds->primary) 4064 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 4065 4066 size = thresholds->primary ? thresholds->primary->size + 1 : 1; 4067 4068 /* Allocate memory for new array of thresholds */ 4069 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold), 4070 GFP_KERNEL); 4071 if (!new) { 4072 ret = -ENOMEM; 4073 goto unlock; 4074 } 4075 new->size = size; 4076 4077 /* Copy thresholds (if any) to new array */ 4078 if (thresholds->primary) { 4079 memcpy(new->entries, thresholds->primary->entries, (size - 1) * 4080 sizeof(struct mem_cgroup_threshold)); 4081 } 4082 4083 /* Add new threshold */ 4084 new->entries[size - 1].eventfd = eventfd; 4085 new->entries[size - 1].threshold = threshold; 4086 4087 /* Sort thresholds. Registering of new threshold isn't time-critical */ 4088 sort(new->entries, size, sizeof(struct mem_cgroup_threshold), 4089 compare_thresholds, NULL); 4090 4091 /* Find current threshold */ 4092 new->current_threshold = -1; 4093 for (i = 0; i < size; i++) { 4094 if (new->entries[i].threshold < usage) { 4095 /* 4096 * new->current_threshold will not be used until 4097 * rcu_assign_pointer(), so it's safe to increment 4098 * it here. 4099 */ 4100 ++new->current_threshold; 4101 } 4102 } 4103 4104 /* Free old spare buffer and save old primary buffer as spare */ 4105 kfree(thresholds->spare); 4106 thresholds->spare = thresholds->primary; 4107 4108 rcu_assign_pointer(thresholds->primary, new); 4109 4110 /* To be sure that nobody uses thresholds */ 4111 synchronize_rcu(); 4112 4113unlock: 4114 mutex_unlock(&memcg->thresholds_lock); 4115 4116 return ret; 4117} 4118 4119static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp, 4120 struct cftype *cft, struct eventfd_ctx *eventfd) 4121{ 4122 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4123 struct mem_cgroup_thresholds *thresholds; 4124 struct mem_cgroup_threshold_ary *new; 4125 int type = MEMFILE_TYPE(cft->private); 4126 u64 usage; 4127 int i, j, size; 4128 4129 mutex_lock(&memcg->thresholds_lock); 4130 if (type == _MEM) 4131 thresholds = &memcg->thresholds; 4132 else if (type == _MEMSWAP) 4133 thresholds = &memcg->memsw_thresholds; 4134 else 4135 BUG(); 4136 4137 /* 4138 * Something went wrong if we trying to unregister a threshold 4139 * if we don't have thresholds 4140 */ 4141 BUG_ON(!thresholds); 4142 4143 usage = mem_cgroup_usage(memcg, type == _MEMSWAP); 4144 4145 /* Check if a threshold crossed before removing */ 4146 __mem_cgroup_threshold(memcg, type == _MEMSWAP); 4147 4148 /* Calculate new number of threshold */ 4149 size = 0; 4150 for (i = 0; i < thresholds->primary->size; i++) { 4151 if (thresholds->primary->entries[i].eventfd != eventfd) 4152 size++; 4153 } 4154 4155 new = thresholds->spare; 4156 4157 /* Set thresholds array to NULL if we don't have thresholds */ 4158 if (!size) { 4159 kfree(new); 4160 new = NULL; 4161 goto swap_buffers; 4162 } 4163 4164 new->size = size; 4165 4166 /* Copy thresholds and find current threshold */ 4167 new->current_threshold = -1; 4168 for (i = 0, j = 0; i < thresholds->primary->size; i++) { 4169 if (thresholds->primary->entries[i].eventfd == eventfd) 4170 continue; 4171 4172 new->entries[j] = thresholds->primary->entries[i]; 4173 if (new->entries[j].threshold < usage) { 4174 /* 4175 * new->current_threshold will not be used 4176 * until rcu_assign_pointer(), so it's safe to increment 4177 * it here. 4178 */ 4179 ++new->current_threshold; 4180 } 4181 j++; 4182 } 4183 4184swap_buffers: 4185 /* Swap primary and spare array */ 4186 thresholds->spare = thresholds->primary; 4187 rcu_assign_pointer(thresholds->primary, new); 4188 4189 /* To be sure that nobody uses thresholds */ 4190 synchronize_rcu(); 4191 4192 mutex_unlock(&memcg->thresholds_lock); 4193} 4194 4195static int mem_cgroup_oom_register_event(struct cgroup *cgrp, 4196 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args) 4197{ 4198 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp); 4199 struct mem_cgroup_eventfd_list *event; 4200 int type = MEMFILE_TYPE(cft->private); 4201 4202 BUG_ON(type != _OOM_TYPE); 4203 event = kmalloc(sizeof(*event), GFP_KERNEL); 4204 if (!event) 4205 return -ENOMEM; 4206 4207 mutex_lock(&memcg_oom_mutex); 4208 4209 event->eventfd = eventfd; 4210 list_add(&event->list, &memcg->oom_notify); 4211 4212 /* already in OOM ? */ 4213 if (atomic_read(&memcg->oom_lock)) 4214 eventfd_signal(eventfd, 1); 4215 mutex_unlock(&memcg_oom_mutex); 4216 4217 return 0; 4218} 4219 4220static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp, 4221 struct cftype *cft, struct eventfd_ctx *eventfd) 4222{ 4223 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 4224 struct mem_cgroup_eventfd_list *ev, *tmp; 4225 int type = MEMFILE_TYPE(cft->private); 4226 4227 BUG_ON(type != _OOM_TYPE); 4228 4229 mutex_lock(&memcg_oom_mutex); 4230 4231 list_for_each_entry_safe(ev, tmp, &mem->oom_notify, list) { 4232 if (ev->eventfd == eventfd) { 4233 list_del(&ev->list); 4234 kfree(ev); 4235 } 4236 } 4237 4238 mutex_unlock(&memcg_oom_mutex); 4239} 4240 4241static int mem_cgroup_oom_control_read(struct cgroup *cgrp, 4242 struct cftype *cft, struct cgroup_map_cb *cb) 4243{ 4244 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 4245 4246 cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable); 4247 4248 if (atomic_read(&mem->oom_lock)) 4249 cb->fill(cb, "under_oom", 1); 4250 else 4251 cb->fill(cb, "under_oom", 0); 4252 return 0; 4253} 4254 4255static int mem_cgroup_oom_control_write(struct cgroup *cgrp, 4256 struct cftype *cft, u64 val) 4257{ 4258 struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp); 4259 struct mem_cgroup *parent; 4260 4261 /* cannot set to root cgroup and only 0 and 1 are allowed */ 4262 if (!cgrp->parent || !((val == 0) || (val == 1))) 4263 return -EINVAL; 4264 4265 parent = mem_cgroup_from_cont(cgrp->parent); 4266 4267 cgroup_lock(); 4268 /* oom-kill-disable is a flag for subhierarchy. */ 4269 if ((parent->use_hierarchy) || 4270 (mem->use_hierarchy && !list_empty(&cgrp->children))) { 4271 cgroup_unlock(); 4272 return -EINVAL; 4273 } 4274 mem->oom_kill_disable = val; 4275 if (!val) 4276 memcg_oom_recover(mem); 4277 cgroup_unlock(); 4278 return 0; 4279} 4280 4281static struct cftype mem_cgroup_files[] = { 4282 { 4283 .name = "usage_in_bytes", 4284 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE), 4285 .read_u64 = mem_cgroup_read, 4286 .register_event = mem_cgroup_usage_register_event, 4287 .unregister_event = mem_cgroup_usage_unregister_event, 4288 }, 4289 { 4290 .name = "max_usage_in_bytes", 4291 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE), 4292 .trigger = mem_cgroup_reset, 4293 .read_u64 = mem_cgroup_read, 4294 }, 4295 { 4296 .name = "limit_in_bytes", 4297 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT), 4298 .write_string = mem_cgroup_write, 4299 .read_u64 = mem_cgroup_read, 4300 }, 4301 { 4302 .name = "soft_limit_in_bytes", 4303 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT), 4304 .write_string = mem_cgroup_write, 4305 .read_u64 = mem_cgroup_read, 4306 }, 4307 { 4308 .name = "failcnt", 4309 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT), 4310 .trigger = mem_cgroup_reset, 4311 .read_u64 = mem_cgroup_read, 4312 }, 4313 { 4314 .name = "stat", 4315 .read_map = mem_control_stat_show, 4316 }, 4317 { 4318 .name = "force_empty", 4319 .trigger = mem_cgroup_force_empty_write, 4320 }, 4321 { 4322 .name = "use_hierarchy", 4323 .write_u64 = mem_cgroup_hierarchy_write, 4324 .read_u64 = mem_cgroup_hierarchy_read, 4325 }, 4326 { 4327 .name = "swappiness", 4328 .read_u64 = mem_cgroup_swappiness_read, 4329 .write_u64 = mem_cgroup_swappiness_write, 4330 }, 4331 { 4332 .name = "move_charge_at_immigrate", 4333 .read_u64 = mem_cgroup_move_charge_read, 4334 .write_u64 = mem_cgroup_move_charge_write, 4335 }, 4336 { 4337 .name = "oom_control", 4338 .read_map = mem_cgroup_oom_control_read, 4339 .write_u64 = mem_cgroup_oom_control_write, 4340 .register_event = mem_cgroup_oom_register_event, 4341 .unregister_event = mem_cgroup_oom_unregister_event, 4342 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL), 4343 }, 4344}; 4345 4346#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4347static struct cftype memsw_cgroup_files[] = { 4348 { 4349 .name = "memsw.usage_in_bytes", 4350 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), 4351 .read_u64 = mem_cgroup_read, 4352 .register_event = mem_cgroup_usage_register_event, 4353 .unregister_event = mem_cgroup_usage_unregister_event, 4354 }, 4355 { 4356 .name = "memsw.max_usage_in_bytes", 4357 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE), 4358 .trigger = mem_cgroup_reset, 4359 .read_u64 = mem_cgroup_read, 4360 }, 4361 { 4362 .name = "memsw.limit_in_bytes", 4363 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT), 4364 .write_string = mem_cgroup_write, 4365 .read_u64 = mem_cgroup_read, 4366 }, 4367 { 4368 .name = "memsw.failcnt", 4369 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT), 4370 .trigger = mem_cgroup_reset, 4371 .read_u64 = mem_cgroup_read, 4372 }, 4373}; 4374 4375static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 4376{ 4377 if (!do_swap_account) 4378 return 0; 4379 return cgroup_add_files(cont, ss, memsw_cgroup_files, 4380 ARRAY_SIZE(memsw_cgroup_files)); 4381}; 4382#else 4383static int register_memsw_files(struct cgroup *cont, struct cgroup_subsys *ss) 4384{ 4385 return 0; 4386} 4387#endif 4388 4389static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 4390{ 4391 struct mem_cgroup_per_node *pn; 4392 struct mem_cgroup_per_zone *mz; 4393 enum lru_list l; 4394 int zone, tmp = node; 4395 /* 4396 * This routine is called against possible nodes. 4397 * But it's BUG to call kmalloc() against offline node. 4398 * 4399 * TODO: this routine can waste much memory for nodes which will 4400 * never be onlined. It's better to use memory hotplug callback 4401 * function. 4402 */ 4403 if (!node_state(node, N_NORMAL_MEMORY)) 4404 tmp = -1; 4405 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp); 4406 if (!pn) 4407 return 1; 4408 4409 mem->info.nodeinfo[node] = pn; 4410 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 4411 mz = &pn->zoneinfo[zone]; 4412 for_each_lru(l) 4413 INIT_LIST_HEAD(&mz->lists[l]); 4414 mz->usage_in_excess = 0; 4415 mz->on_tree = false; 4416 mz->mem = mem; 4417 } 4418 return 0; 4419} 4420 4421static void free_mem_cgroup_per_zone_info(struct mem_cgroup *mem, int node) 4422{ 4423 kfree(mem->info.nodeinfo[node]); 4424} 4425 4426static struct mem_cgroup *mem_cgroup_alloc(void) 4427{ 4428 struct mem_cgroup *mem; 4429 int size = sizeof(struct mem_cgroup); 4430 4431 /* Can be very big if MAX_NUMNODES is very big */ 4432 if (size < PAGE_SIZE) 4433 mem = kzalloc(size, GFP_KERNEL); 4434 else 4435 mem = vzalloc(size); 4436 4437 if (!mem) 4438 return NULL; 4439 4440 mem->stat = alloc_percpu(struct mem_cgroup_stat_cpu); 4441 if (!mem->stat) 4442 goto out_free; 4443 spin_lock_init(&mem->pcp_counter_lock); 4444 return mem; 4445 4446out_free: 4447 if (size < PAGE_SIZE) 4448 kfree(mem); 4449 else 4450 vfree(mem); 4451 return NULL; 4452} 4453 4454/* 4455 * At destroying mem_cgroup, references from swap_cgroup can remain. 4456 * (scanning all at force_empty is too costly...) 4457 * 4458 * Instead of clearing all references at force_empty, we remember 4459 * the number of reference from swap_cgroup and free mem_cgroup when 4460 * it goes down to 0. 4461 * 4462 * Removal of cgroup itself succeeds regardless of refs from swap. 4463 */ 4464 4465static void __mem_cgroup_free(struct mem_cgroup *mem) 4466{ 4467 int node; 4468 4469 mem_cgroup_remove_from_trees(mem); 4470 free_css_id(&mem_cgroup_subsys, &mem->css); 4471 4472 for_each_node_state(node, N_POSSIBLE) 4473 free_mem_cgroup_per_zone_info(mem, node); 4474 4475 free_percpu(mem->stat); 4476 if (sizeof(struct mem_cgroup) < PAGE_SIZE) 4477 kfree(mem); 4478 else 4479 vfree(mem); 4480} 4481 4482static void mem_cgroup_get(struct mem_cgroup *mem) 4483{ 4484 atomic_inc(&mem->refcnt); 4485} 4486 4487static void __mem_cgroup_put(struct mem_cgroup *mem, int count) 4488{ 4489 if (atomic_sub_and_test(count, &mem->refcnt)) { 4490 struct mem_cgroup *parent = parent_mem_cgroup(mem); 4491 __mem_cgroup_free(mem); 4492 if (parent) 4493 mem_cgroup_put(parent); 4494 } 4495} 4496 4497static void mem_cgroup_put(struct mem_cgroup *mem) 4498{ 4499 __mem_cgroup_put(mem, 1); 4500} 4501 4502/* 4503 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled. 4504 */ 4505static struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *mem) 4506{ 4507 if (!mem->res.parent) 4508 return NULL; 4509 return mem_cgroup_from_res_counter(mem->res.parent, res); 4510} 4511 4512#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 4513static void __init enable_swap_cgroup(void) 4514{ 4515 if (!mem_cgroup_disabled() && really_do_swap_account) 4516 do_swap_account = 1; 4517} 4518#else 4519static void __init enable_swap_cgroup(void) 4520{ 4521} 4522#endif 4523 4524static int mem_cgroup_soft_limit_tree_init(void) 4525{ 4526 struct mem_cgroup_tree_per_node *rtpn; 4527 struct mem_cgroup_tree_per_zone *rtpz; 4528 int tmp, node, zone; 4529 4530 for_each_node_state(node, N_POSSIBLE) { 4531 tmp = node; 4532 if (!node_state(node, N_NORMAL_MEMORY)) 4533 tmp = -1; 4534 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp); 4535 if (!rtpn) 4536 return 1; 4537 4538 soft_limit_tree.rb_tree_per_node[node] = rtpn; 4539 4540 for (zone = 0; zone < MAX_NR_ZONES; zone++) { 4541 rtpz = &rtpn->rb_tree_per_zone[zone]; 4542 rtpz->rb_root = RB_ROOT; 4543 spin_lock_init(&rtpz->lock); 4544 } 4545 } 4546 return 0; 4547} 4548 4549static struct cgroup_subsys_state * __ref 4550mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) 4551{ 4552 struct mem_cgroup *mem, *parent; 4553 long error = -ENOMEM; 4554 int node; 4555 4556 mem = mem_cgroup_alloc(); 4557 if (!mem) 4558 return ERR_PTR(error); 4559 4560 for_each_node_state(node, N_POSSIBLE) 4561 if (alloc_mem_cgroup_per_zone_info(mem, node)) 4562 goto free_out; 4563 4564 /* root ? */ 4565 if (cont->parent == NULL) { 4566 int cpu; 4567 enable_swap_cgroup(); 4568 parent = NULL; 4569 root_mem_cgroup = mem; 4570 if (mem_cgroup_soft_limit_tree_init()) 4571 goto free_out; 4572 for_each_possible_cpu(cpu) { 4573 struct memcg_stock_pcp *stock = 4574 &per_cpu(memcg_stock, cpu); 4575 INIT_WORK(&stock->work, drain_local_stock); 4576 } 4577 hotcpu_notifier(memcg_cpu_hotplug_callback, 0); 4578 } else { 4579 parent = mem_cgroup_from_cont(cont->parent); 4580 mem->use_hierarchy = parent->use_hierarchy; 4581 mem->oom_kill_disable = parent->oom_kill_disable; 4582 } 4583 4584 if (parent && parent->use_hierarchy) { 4585 res_counter_init(&mem->res, &parent->res); 4586 res_counter_init(&mem->memsw, &parent->memsw); 4587 /* 4588 * We increment refcnt of the parent to ensure that we can 4589 * safely access it on res_counter_charge/uncharge. 4590 * This refcnt will be decremented when freeing this 4591 * mem_cgroup(see mem_cgroup_put). 4592 */ 4593 mem_cgroup_get(parent); 4594 } else { 4595 res_counter_init(&mem->res, NULL); 4596 res_counter_init(&mem->memsw, NULL); 4597 } 4598 mem->last_scanned_child = 0; 4599 INIT_LIST_HEAD(&mem->oom_notify); 4600 4601 if (parent) 4602 mem->swappiness = get_swappiness(parent); 4603 atomic_set(&mem->refcnt, 1); 4604 mem->move_charge_at_immigrate = 0; 4605 mutex_init(&mem->thresholds_lock); 4606 return &mem->css; 4607free_out: 4608 __mem_cgroup_free(mem); 4609 root_mem_cgroup = NULL; 4610 return ERR_PTR(error); 4611} 4612 4613static int mem_cgroup_pre_destroy(struct cgroup_subsys *ss, 4614 struct cgroup *cont) 4615{ 4616 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 4617 4618 return mem_cgroup_force_empty(mem, false); 4619} 4620 4621static void mem_cgroup_destroy(struct cgroup_subsys *ss, 4622 struct cgroup *cont) 4623{ 4624 struct mem_cgroup *mem = mem_cgroup_from_cont(cont); 4625 4626 mem_cgroup_put(mem); 4627} 4628 4629static int mem_cgroup_populate(struct cgroup_subsys *ss, 4630 struct cgroup *cont) 4631{ 4632 int ret; 4633 4634 ret = cgroup_add_files(cont, ss, mem_cgroup_files, 4635 ARRAY_SIZE(mem_cgroup_files)); 4636 4637 if (!ret) 4638 ret = register_memsw_files(cont, ss); 4639 return ret; 4640} 4641 4642#ifdef CONFIG_MMU 4643/* Handlers for move charge at task migration. */ 4644#define PRECHARGE_COUNT_AT_ONCE 256 4645static int mem_cgroup_do_precharge(unsigned long count) 4646{ 4647 int ret = 0; 4648 int batch_count = PRECHARGE_COUNT_AT_ONCE; 4649 struct mem_cgroup *mem = mc.to; 4650 4651 if (mem_cgroup_is_root(mem)) { 4652 mc.precharge += count; 4653 /* we don't need css_get for root */ 4654 return ret; 4655 } 4656 /* try to charge at once */ 4657 if (count > 1) { 4658 struct res_counter *dummy; 4659 /* 4660 * "mem" cannot be under rmdir() because we've already checked 4661 * by cgroup_lock_live_cgroup() that it is not removed and we 4662 * are still under the same cgroup_mutex. So we can postpone 4663 * css_get(). 4664 */ 4665 if (res_counter_charge(&mem->res, PAGE_SIZE * count, &dummy)) 4666 goto one_by_one; 4667 if (do_swap_account && res_counter_charge(&mem->memsw, 4668 PAGE_SIZE * count, &dummy)) { 4669 res_counter_uncharge(&mem->res, PAGE_SIZE * count); 4670 goto one_by_one; 4671 } 4672 mc.precharge += count; 4673 return ret; 4674 } 4675one_by_one: 4676 /* fall back to one by one charge */ 4677 while (count--) { 4678 if (signal_pending(current)) { 4679 ret = -EINTR; 4680 break; 4681 } 4682 if (!batch_count--) { 4683 batch_count = PRECHARGE_COUNT_AT_ONCE; 4684 cond_resched(); 4685 } 4686 ret = __mem_cgroup_try_charge(NULL, GFP_KERNEL, 1, &mem, false); 4687 if (ret || !mem) 4688 /* mem_cgroup_clear_mc() will do uncharge later */ 4689 return -ENOMEM; 4690 mc.precharge++; 4691 } 4692 return ret; 4693} 4694 4695/** 4696 * is_target_pte_for_mc - check a pte whether it is valid for move charge 4697 * @vma: the vma the pte to be checked belongs 4698 * @addr: the address corresponding to the pte to be checked 4699 * @ptent: the pte to be checked 4700 * @target: the pointer the target page or swap ent will be stored(can be NULL) 4701 * 4702 * Returns 4703 * 0(MC_TARGET_NONE): if the pte is not a target for move charge. 4704 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for 4705 * move charge. if @target is not NULL, the page is stored in target->page 4706 * with extra refcnt got(Callers should handle it). 4707 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a 4708 * target for charge migration. if @target is not NULL, the entry is stored 4709 * in target->ent. 4710 * 4711 * Called with pte lock held. 4712 */ 4713union mc_target { 4714 struct page *page; 4715 swp_entry_t ent; 4716}; 4717 4718enum mc_target_type { 4719 MC_TARGET_NONE, /* not used */ 4720 MC_TARGET_PAGE, 4721 MC_TARGET_SWAP, 4722}; 4723 4724static struct page *mc_handle_present_pte(struct vm_area_struct *vma, 4725 unsigned long addr, pte_t ptent) 4726{ 4727 struct page *page = vm_normal_page(vma, addr, ptent); 4728 4729 if (!page || !page_mapped(page)) 4730 return NULL; 4731 if (PageAnon(page)) { 4732 /* we don't move shared anon */ 4733 if (!move_anon() || page_mapcount(page) > 2) 4734 return NULL; 4735 } else if (!move_file()) 4736 /* we ignore mapcount for file pages */ 4737 return NULL; 4738 if (!get_page_unless_zero(page)) 4739 return NULL; 4740 4741 return page; 4742} 4743 4744static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, 4745 unsigned long addr, pte_t ptent, swp_entry_t *entry) 4746{ 4747 int usage_count; 4748 struct page *page = NULL; 4749 swp_entry_t ent = pte_to_swp_entry(ptent); 4750 4751 if (!move_anon() || non_swap_entry(ent)) 4752 return NULL; 4753 usage_count = mem_cgroup_count_swap_user(ent, &page); 4754 if (usage_count > 1) { /* we don't move shared anon */ 4755 if (page) 4756 put_page(page); 4757 return NULL; 4758 } 4759 if (do_swap_account) 4760 entry->val = ent.val; 4761 4762 return page; 4763} 4764 4765static struct page *mc_handle_file_pte(struct vm_area_struct *vma, 4766 unsigned long addr, pte_t ptent, swp_entry_t *entry) 4767{ 4768 struct page *page = NULL; 4769 struct inode *inode; 4770 struct address_space *mapping; 4771 pgoff_t pgoff; 4772 4773 if (!vma->vm_file) /* anonymous vma */ 4774 return NULL; 4775 if (!move_file()) 4776 return NULL; 4777 4778 inode = vma->vm_file->f_path.dentry->d_inode; 4779 mapping = vma->vm_file->f_mapping; 4780 if (pte_none(ptent)) 4781 pgoff = linear_page_index(vma, addr); 4782 else /* pte_file(ptent) is true */ 4783 pgoff = pte_to_pgoff(ptent); 4784 4785 /* page is moved even if it's not RSS of this task(page-faulted). */ 4786 if (!mapping_cap_swap_backed(mapping)) { /* normal file */ 4787 page = find_get_page(mapping, pgoff); 4788 } else { /* shmem/tmpfs file. we should take account of swap too. */ 4789 swp_entry_t ent; 4790 mem_cgroup_get_shmem_target(inode, pgoff, &page, &ent); 4791 if (do_swap_account) 4792 entry->val = ent.val; 4793 } 4794 4795 return page; 4796} 4797 4798static int is_target_pte_for_mc(struct vm_area_struct *vma, 4799 unsigned long addr, pte_t ptent, union mc_target *target) 4800{ 4801 struct page *page = NULL; 4802 struct page_cgroup *pc; 4803 int ret = 0; 4804 swp_entry_t ent = { .val = 0 }; 4805 4806 if (pte_present(ptent)) 4807 page = mc_handle_present_pte(vma, addr, ptent); 4808 else if (is_swap_pte(ptent)) 4809 page = mc_handle_swap_pte(vma, addr, ptent, &ent); 4810 else if (pte_none(ptent) || pte_file(ptent)) 4811 page = mc_handle_file_pte(vma, addr, ptent, &ent); 4812 4813 if (!page && !ent.val) 4814 return 0; 4815 if (page) { 4816 pc = lookup_page_cgroup(page); 4817 /* 4818 * Do only loose check w/o page_cgroup lock. 4819 * mem_cgroup_move_account() checks the pc is valid or not under 4820 * the lock. 4821 */ 4822 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) { 4823 ret = MC_TARGET_PAGE; 4824 if (target) 4825 target->page = page; 4826 } 4827 if (!ret || !target) 4828 put_page(page); 4829 } 4830 /* There is a swap entry and a page doesn't exist or isn't charged */ 4831 if (ent.val && !ret && 4832 css_id(&mc.from->css) == lookup_swap_cgroup(ent)) { 4833 ret = MC_TARGET_SWAP; 4834 if (target) 4835 target->ent = ent; 4836 } 4837 return ret; 4838} 4839 4840static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, 4841 unsigned long addr, unsigned long end, 4842 struct mm_walk *walk) 4843{ 4844 struct vm_area_struct *vma = walk->private; 4845 pte_t *pte; 4846 spinlock_t *ptl; 4847 4848 split_huge_page_pmd(walk->mm, pmd); 4849 4850 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 4851 for (; addr != end; pte++, addr += PAGE_SIZE) 4852 if (is_target_pte_for_mc(vma, addr, *pte, NULL)) 4853 mc.precharge++; /* increment precharge temporarily */ 4854 pte_unmap_unlock(pte - 1, ptl); 4855 cond_resched(); 4856 4857 return 0; 4858} 4859 4860static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm) 4861{ 4862 unsigned long precharge; 4863 struct vm_area_struct *vma; 4864 4865 down_read(&mm->mmap_sem); 4866 for (vma = mm->mmap; vma; vma = vma->vm_next) { 4867 struct mm_walk mem_cgroup_count_precharge_walk = { 4868 .pmd_entry = mem_cgroup_count_precharge_pte_range, 4869 .mm = mm, 4870 .private = vma, 4871 }; 4872 if (is_vm_hugetlb_page(vma)) 4873 continue; 4874 walk_page_range(vma->vm_start, vma->vm_end, 4875 &mem_cgroup_count_precharge_walk); 4876 } 4877 up_read(&mm->mmap_sem); 4878 4879 precharge = mc.precharge; 4880 mc.precharge = 0; 4881 4882 return precharge; 4883} 4884 4885static int mem_cgroup_precharge_mc(struct mm_struct *mm) 4886{ 4887 unsigned long precharge = mem_cgroup_count_precharge(mm); 4888 4889 VM_BUG_ON(mc.moving_task); 4890 mc.moving_task = current; 4891 return mem_cgroup_do_precharge(precharge); 4892} 4893 4894/* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */ 4895static void __mem_cgroup_clear_mc(void) 4896{ 4897 struct mem_cgroup *from = mc.from; 4898 struct mem_cgroup *to = mc.to; 4899 4900 /* we must uncharge all the leftover precharges from mc.to */ 4901 if (mc.precharge) { 4902 __mem_cgroup_cancel_charge(mc.to, mc.precharge); 4903 mc.precharge = 0; 4904 } 4905 /* 4906 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so 4907 * we must uncharge here. 4908 */ 4909 if (mc.moved_charge) { 4910 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge); 4911 mc.moved_charge = 0; 4912 } 4913 /* we must fixup refcnts and charges */ 4914 if (mc.moved_swap) { 4915 /* uncharge swap account from the old cgroup */ 4916 if (!mem_cgroup_is_root(mc.from)) 4917 res_counter_uncharge(&mc.from->memsw, 4918 PAGE_SIZE * mc.moved_swap); 4919 __mem_cgroup_put(mc.from, mc.moved_swap); 4920 4921 if (!mem_cgroup_is_root(mc.to)) { 4922 /* 4923 * we charged both to->res and to->memsw, so we should 4924 * uncharge to->res. 4925 */ 4926 res_counter_uncharge(&mc.to->res, 4927 PAGE_SIZE * mc.moved_swap); 4928 } 4929 /* we've already done mem_cgroup_get(mc.to) */ 4930 mc.moved_swap = 0; 4931 } 4932 memcg_oom_recover(from); 4933 memcg_oom_recover(to); 4934 wake_up_all(&mc.waitq); 4935} 4936 4937static void mem_cgroup_clear_mc(void) 4938{ 4939 struct mem_cgroup *from = mc.from; 4940 4941 /* 4942 * we must clear moving_task before waking up waiters at the end of 4943 * task migration. 4944 */ 4945 mc.moving_task = NULL; 4946 __mem_cgroup_clear_mc(); 4947 spin_lock(&mc.lock); 4948 mc.from = NULL; 4949 mc.to = NULL; 4950 spin_unlock(&mc.lock); 4951 mem_cgroup_end_move(from); 4952} 4953 4954static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 4955 struct cgroup *cgroup, 4956 struct task_struct *p) 4957{ 4958 int ret = 0; 4959 struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup); 4960 4961 if (mem->move_charge_at_immigrate) { 4962 struct mm_struct *mm; 4963 struct mem_cgroup *from = mem_cgroup_from_task(p); 4964 4965 VM_BUG_ON(from == mem); 4966 4967 mm = get_task_mm(p); 4968 if (!mm) 4969 return 0; 4970 /* We move charges only when we move a owner of the mm */ 4971 if (mm->owner == p) { 4972 VM_BUG_ON(mc.from); 4973 VM_BUG_ON(mc.to); 4974 VM_BUG_ON(mc.precharge); 4975 VM_BUG_ON(mc.moved_charge); 4976 VM_BUG_ON(mc.moved_swap); 4977 mem_cgroup_start_move(from); 4978 spin_lock(&mc.lock); 4979 mc.from = from; 4980 mc.to = mem; 4981 spin_unlock(&mc.lock); 4982 /* We set mc.moving_task later */ 4983 4984 ret = mem_cgroup_precharge_mc(mm); 4985 if (ret) 4986 mem_cgroup_clear_mc(); 4987 } 4988 mmput(mm); 4989 } 4990 return ret; 4991} 4992 4993static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 4994 struct cgroup *cgroup, 4995 struct task_struct *p) 4996{ 4997 mem_cgroup_clear_mc(); 4998} 4999 5000static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, 5001 unsigned long addr, unsigned long end, 5002 struct mm_walk *walk) 5003{ 5004 int ret = 0; 5005 struct vm_area_struct *vma = walk->private; 5006 pte_t *pte; 5007 spinlock_t *ptl; 5008 5009 split_huge_page_pmd(walk->mm, pmd); 5010retry: 5011 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); 5012 for (; addr != end; addr += PAGE_SIZE) { 5013 pte_t ptent = *(pte++); 5014 union mc_target target; 5015 int type; 5016 struct page *page; 5017 struct page_cgroup *pc; 5018 swp_entry_t ent; 5019 5020 if (!mc.precharge) 5021 break; 5022 5023 type = is_target_pte_for_mc(vma, addr, ptent, &target); 5024 switch (type) { 5025 case MC_TARGET_PAGE: 5026 page = target.page; 5027 if (isolate_lru_page(page)) 5028 goto put; 5029 pc = lookup_page_cgroup(page); 5030 if (!mem_cgroup_move_account(page, 1, pc, 5031 mc.from, mc.to, false)) { 5032 mc.precharge--; 5033 /* we uncharge from mc.from later. */ 5034 mc.moved_charge++; 5035 } 5036 putback_lru_page(page); 5037put: /* is_target_pte_for_mc() gets the page */ 5038 put_page(page); 5039 break; 5040 case MC_TARGET_SWAP: 5041 ent = target.ent; 5042 if (!mem_cgroup_move_swap_account(ent, 5043 mc.from, mc.to, false)) { 5044 mc.precharge--; 5045 /* we fixup refcnts and charges later. */ 5046 mc.moved_swap++; 5047 } 5048 break; 5049 default: 5050 break; 5051 } 5052 } 5053 pte_unmap_unlock(pte - 1, ptl); 5054 cond_resched(); 5055 5056 if (addr != end) { 5057 /* 5058 * We have consumed all precharges we got in can_attach(). 5059 * We try charge one by one, but don't do any additional 5060 * charges to mc.to if we have failed in charge once in attach() 5061 * phase. 5062 */ 5063 ret = mem_cgroup_do_precharge(1); 5064 if (!ret) 5065 goto retry; 5066 } 5067 5068 return ret; 5069} 5070 5071static void mem_cgroup_move_charge(struct mm_struct *mm) 5072{ 5073 struct vm_area_struct *vma; 5074 5075 lru_add_drain_all(); 5076retry: 5077 if (unlikely(!down_read_trylock(&mm->mmap_sem))) { 5078 /* 5079 * Someone who are holding the mmap_sem might be waiting in 5080 * waitq. So we cancel all extra charges, wake up all waiters, 5081 * and retry. Because we cancel precharges, we might not be able 5082 * to move enough charges, but moving charge is a best-effort 5083 * feature anyway, so it wouldn't be a big problem. 5084 */ 5085 __mem_cgroup_clear_mc(); 5086 cond_resched(); 5087 goto retry; 5088 } 5089 for (vma = mm->mmap; vma; vma = vma->vm_next) { 5090 int ret; 5091 struct mm_walk mem_cgroup_move_charge_walk = { 5092 .pmd_entry = mem_cgroup_move_charge_pte_range, 5093 .mm = mm, 5094 .private = vma, 5095 }; 5096 if (is_vm_hugetlb_page(vma)) 5097 continue; 5098 ret = walk_page_range(vma->vm_start, vma->vm_end, 5099 &mem_cgroup_move_charge_walk); 5100 if (ret) 5101 /* 5102 * means we have consumed all precharges and failed in 5103 * doing additional charge. Just abandon here. 5104 */ 5105 break; 5106 } 5107 up_read(&mm->mmap_sem); 5108} 5109 5110static void mem_cgroup_move_task(struct cgroup_subsys *ss, 5111 struct cgroup *cont, 5112 struct cgroup *old_cont, 5113 struct task_struct *p) 5114{ 5115 struct mm_struct *mm; 5116 5117 if (!mc.to) 5118 /* no need to move charge */ 5119 return; 5120 5121 mm = get_task_mm(p); 5122 if (mm) { 5123 mem_cgroup_move_charge(mm); 5124 mmput(mm); 5125 } 5126 mem_cgroup_clear_mc(); 5127} 5128#else /* !CONFIG_MMU */ 5129static int mem_cgroup_can_attach(struct cgroup_subsys *ss, 5130 struct cgroup *cgroup, 5131 struct task_struct *p) 5132{ 5133 return 0; 5134} 5135static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss, 5136 struct cgroup *cgroup, 5137 struct task_struct *p) 5138{ 5139} 5140static void mem_cgroup_move_task(struct cgroup_subsys *ss, 5141 struct cgroup *cont, 5142 struct cgroup *old_cont, 5143 struct task_struct *p) 5144{ 5145} 5146#endif 5147 5148struct cgroup_subsys mem_cgroup_subsys = { 5149 .name = "memory", 5150 .subsys_id = mem_cgroup_subsys_id, 5151 .create = mem_cgroup_create, 5152 .pre_destroy = mem_cgroup_pre_destroy, 5153 .destroy = mem_cgroup_destroy, 5154 .populate = mem_cgroup_populate, 5155 .can_attach = mem_cgroup_can_attach, 5156 .cancel_attach = mem_cgroup_cancel_attach, 5157 .attach = mem_cgroup_move_task, 5158 .early_init = 0, 5159 .use_id = 1, 5160}; 5161 5162#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP 5163static int __init enable_swap_account(char *s) 5164{ 5165 /* consider enabled if no parameter or 1 is given */ 5166 if (!strcmp(s, "1")) 5167 really_do_swap_account = 1; 5168 else if (!strcmp(s, "0")) 5169 really_do_swap_account = 0; 5170 return 1; 5171} 5172__setup("swapaccount=", enable_swap_account); 5173 5174#endif 5175