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