include/linux/memcontrol.h

   1 /* memcontrol.h - 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  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  */
  19
  20 #ifndef _LINUX_MEMCONTROL_H
  21 #define _LINUX_MEMCONTROL_H
  22 #include <linux/cgroup.h>
  23 #include <linux/vm_event_item.h>
  24 #include <linux/hardirq.h>
  25 #include <linux/jump_label.h>
  26
  27 struct mem_cgroup;
  28 struct page_cgroup;
  29 struct page;
  30 struct mm_struct;
  31 struct kmem_cache;
  32
  33 /*
  34  * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
  35  * These two lists should keep in accord with each other.
  36  */
  37 enum mem_cgroup_stat_index {
  38         /*
  39          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
  40          */
  41         MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
  42         MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
  43         MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
  44         MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
  45         MEM_CGROUP_STAT_WRITEBACK,      /* # of pages under writeback */
  46         MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
  47         MEM_CGROUP_STAT_NSTATS,
  48 };
  49
  50 struct mem_cgroup_reclaim_cookie {
  51         struct zone *zone;
  52         int priority;
  53         unsigned int generation;
  54 };
  55
  56 enum mem_cgroup_filter_t {
  57         VISIT,          /* visit current node */
  58         SKIP,           /* skip the current node and continue traversal */
  59         SKIP_TREE,      /* skip the whole subtree and continue traversal */
  60 };
  61
  62 /*
  63  * mem_cgroup_filter_t predicate might instruct mem_cgroup_iter_cond how to
  64  * iterate through the hierarchy tree. Each tree element is checked by the
  65  * predicate before it is returned by the iterator. If a filter returns
  66  * SKIP or SKIP_TREE then the iterator code continues traversal (with the
  67  * next node down the hierarchy or the next node that doesn't belong under the
  68  * memcg's subtree).
  69  */
  70 typedef enum mem_cgroup_filter_t
  71 (*mem_cgroup_iter_filter)(struct mem_cgroup *memcg, struct mem_cgroup *root);
  72
  73 #ifdef CONFIG_MEMCG
  74 /*
  75  * All "charge" functions with gfp_mask should use GFP_KERNEL or
  76  * (gfp_mask & GFP_RECLAIM_MASK). In current implementatin, memcg doesn't
  77  * alloc memory but reclaims memory from all available zones. So, "where I want
  78  * memory from" bits of gfp_mask has no meaning. So any bits of that field is
  79  * available but adding a rule is better. charge functions' gfp_mask should
  80  * be set to GFP_KERNEL or gfp_mask & GFP_RECLAIM_MASK for avoiding ambiguous
  81  * codes.
  82  * (Of course, if memcg does memory allocation in future, GFP_KERNEL is sane.)
  83  */
  84
  85 extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
  86                                 gfp_t gfp_mask);
  87 /* for swap handling */
  88 extern int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
  89                 struct page *page, gfp_t mask, struct mem_cgroup **memcgp);
  90 extern void mem_cgroup_commit_charge_swapin(struct page *page,
  91                                         struct mem_cgroup *memcg);
  92 extern void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg);
  93
  94 extern int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
  95                                         gfp_t gfp_mask);
  96
  97 struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
  98 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
  99
 100 /* For coalescing uncharge for reducing memcg' overhead*/
 101 extern void mem_cgroup_uncharge_start(void);
 102 extern void mem_cgroup_uncharge_end(void);
 103
 104 extern void mem_cgroup_uncharge_page(struct page *page);
 105 extern void mem_cgroup_uncharge_cache_page(struct page *page);
 106
 107 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
 108                                   struct mem_cgroup *memcg);
 109 bool task_in_mem_cgroup(struct task_struct *task,
 110                         const struct mem_cgroup *memcg);
 111
 112 extern struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page);
 113 extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 114 extern struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm);
 115
 116 extern struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
 117 extern struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css);
 118
 119 static inline
 120 bool mm_match_cgroup(const struct mm_struct *mm, const struct mem_cgroup *memcg)
 121 {
 122         struct mem_cgroup *task_memcg;
 123         bool match;
 124
 125         rcu_read_lock();
 126         task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 127         match = __mem_cgroup_same_or_subtree(memcg, task_memcg);
 128         rcu_read_unlock();
 129         return match;
 130 }
 131
 132 extern struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg);
 133
 134 extern void
 135 mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
 136                              struct mem_cgroup **memcgp);
 137 extern void mem_cgroup_end_migration(struct mem_cgroup *memcg,
 138         struct page *oldpage, struct page *newpage, bool migration_ok);
 139
 140 struct mem_cgroup *mem_cgroup_iter_cond(struct mem_cgroup *root,
 141                                    struct mem_cgroup *prev,
 142                                    struct mem_cgroup_reclaim_cookie *reclaim,
 143                                    mem_cgroup_iter_filter cond);
 144
 145 static inline struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 146                                    struct mem_cgroup *prev,
 147                                    struct mem_cgroup_reclaim_cookie *reclaim)
 148 {
 149         return mem_cgroup_iter_cond(root, prev, reclaim, NULL);
 150 }
 151
 152 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
 153
 154 /*
 155  * For memory reclaim.
 156  */
 157 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec);
 158 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
 159 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list);
 160 void mem_cgroup_update_lru_size(struct lruvec *, enum lru_list, int);
 161 extern void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 162                                         struct task_struct *p);
 163 extern void mem_cgroup_replace_page_cache(struct page *oldpage,
 164                                         struct page *newpage);
 165
 166 /**
 167  * mem_cgroup_toggle_oom - toggle the memcg OOM killer for the current task
 168  * @new: true to enable, false to disable
 169  *
 170  * Toggle whether a failed memcg charge should invoke the OOM killer
 171  * or just return -ENOMEM.  Returns the previous toggle state.
 172  *
 173  * NOTE: Any path that enables the OOM killer before charging must
 174  *       call mem_cgroup_oom_synchronize() afterward to finalize the
 175  *       OOM handling and clean up.
 176  */
 177 static inline bool mem_cgroup_toggle_oom(bool new)
 178 {
 179         bool old;
 180
 181         old = current->memcg_oom.may_oom;
 182         current->memcg_oom.may_oom = new;
 183
 184         return old;
 185 }
 186
 187 static inline void mem_cgroup_enable_oom(void)
 188 {
 189         bool old = mem_cgroup_toggle_oom(true);
 190
 191         WARN_ON(old == true);
 192 }
 193
 194 static inline void mem_cgroup_disable_oom(void)
 195 {
 196         bool old = mem_cgroup_toggle_oom(false);
 197
 198         WARN_ON(old == false);
 199 }
 200
 201 static inline bool task_in_memcg_oom(struct task_struct *p)
 202 {
 203         return p->memcg_oom.in_memcg_oom;
 204 }
 205
 206 bool mem_cgroup_oom_synchronize(void);
 207
 208 #ifdef CONFIG_MEMCG_SWAP
 209 extern int do_swap_account;
 210 #endif
 211
 212 static inline bool mem_cgroup_disabled(void)
 213 {
 214         if (mem_cgroup_subsys.disabled)
 215                 return true;
 216         return false;
 217 }
 218
 219 void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
 220                                          unsigned long *flags);
 221
 222 extern atomic_t memcg_moving;
 223
 224 static inline void mem_cgroup_begin_update_page_stat(struct page *page,
 225                                         bool *locked, unsigned long *flags)
 226 {
 227         if (mem_cgroup_disabled())
 228                 return;
 229         rcu_read_lock();
 230         *locked = false;
 231         if (atomic_read(&memcg_moving))
 232                 __mem_cgroup_begin_update_page_stat(page, locked, flags);
 233 }
 234
 235 void __mem_cgroup_end_update_page_stat(struct page *page,
 236                                 unsigned long *flags);
 237 static inline void mem_cgroup_end_update_page_stat(struct page *page,
 238                                         bool *locked, unsigned long *flags)
 239 {
 240         if (mem_cgroup_disabled())
 241                 return;
 242         if (*locked)
 243                 __mem_cgroup_end_update_page_stat(page, flags);
 244         rcu_read_unlock();
 245 }
 246
 247 void mem_cgroup_update_page_stat(struct page *page,
 248                                  enum mem_cgroup_stat_index idx,
 249                                  int val);
 250
 251 static inline void mem_cgroup_inc_page_stat(struct page *page,
 252                                             enum mem_cgroup_stat_index idx)
 253 {
 254         mem_cgroup_update_page_stat(page, idx, 1);
 255 }
 256
 257 static inline void mem_cgroup_dec_page_stat(struct page *page,
 258                                             enum mem_cgroup_stat_index idx)
 259 {
 260         mem_cgroup_update_page_stat(page, idx, -1);
 261 }
 262
 263 enum mem_cgroup_filter_t
 264 mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
 265                 struct mem_cgroup *root);
 266
 267 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
 268 static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
 269                                              enum vm_event_item idx)
 270 {
 271         if (mem_cgroup_disabled())
 272                 return;
 273         __mem_cgroup_count_vm_event(mm, idx);
 274 }
 275 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 276 void mem_cgroup_split_huge_fixup(struct page *head);
 277 #endif
 278
 279 #ifdef CONFIG_DEBUG_VM
 280 bool mem_cgroup_bad_page_check(struct page *page);
 281 void mem_cgroup_print_bad_page(struct page *page);
 282 #endif
 283 #else /* CONFIG_MEMCG */
 284 struct mem_cgroup;
 285
 286 static inline int mem_cgroup_newpage_charge(struct page *page,
 287                                         struct mm_struct *mm, gfp_t gfp_mask)
 288 {
 289         return 0;
 290 }
 291
 292 static inline int mem_cgroup_cache_charge(struct page *page,
 293                                         struct mm_struct *mm, gfp_t gfp_mask)
 294 {
 295         return 0;
 296 }
 297
 298 static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 299                 struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp)
 300 {
 301         return 0;
 302 }
 303
 304 static inline void mem_cgroup_commit_charge_swapin(struct page *page,
 305                                           struct mem_cgroup *memcg)
 306 {
 307 }
 308
 309 static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
 310 {
 311 }
 312
 313 static inline void mem_cgroup_uncharge_start(void)
 314 {
 315 }
 316
 317 static inline void mem_cgroup_uncharge_end(void)
 318 {
 319 }
 320
 321 static inline void mem_cgroup_uncharge_page(struct page *page)
 322 {
 323 }
 324
 325 static inline void mem_cgroup_uncharge_cache_page(struct page *page)
 326 {
 327 }
 328
 329 static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
 330                                                     struct mem_cgroup *memcg)
 331 {
 332         return &zone->lruvec;
 333 }
 334
 335 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 336                                                     struct zone *zone)
 337 {
 338         return &zone->lruvec;
 339 }
 340
 341 static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 342 {
 343         return NULL;
 344 }
 345
 346 static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 347 {
 348         return NULL;
 349 }
 350
 351 static inline bool mm_match_cgroup(struct mm_struct *mm,
 352                 struct mem_cgroup *memcg)
 353 {
 354         return true;
 355 }
 356
 357 static inline bool task_in_mem_cgroup(struct task_struct *task,
 358                                       const struct mem_cgroup *memcg)
 359 {
 360         return true;
 361 }
 362
 363 static inline struct cgroup_subsys_state
 364                 *mem_cgroup_css(struct mem_cgroup *memcg)
 365 {
 366         return NULL;
 367 }
 368
 369 static inline void
 370 mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
 371                              struct mem_cgroup **memcgp)
 372 {
 373 }
 374
 375 static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
 376                 struct page *oldpage, struct page *newpage, bool migration_ok)
 377 {
 378 }
 379 static inline struct mem_cgroup *
 380 mem_cgroup_iter_cond(struct mem_cgroup *root,
 381                 struct mem_cgroup *prev,
 382                 struct mem_cgroup_reclaim_cookie *reclaim,
 383                 mem_cgroup_iter_filter cond)
 384 {
 385         /* first call must return non-NULL, second return NULL */
 386         return (struct mem_cgroup *)(unsigned long)!prev;
 387 }
 388
 389 static inline struct mem_cgroup *
 390 mem_cgroup_iter(struct mem_cgroup *root,
 391                 struct mem_cgroup *prev,
 392                 struct mem_cgroup_reclaim_cookie *reclaim)
 393 {
 394         return NULL;
 395 }
 396
 397 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 398                                          struct mem_cgroup *prev)
 399 {
 400 }
 401
 402 static inline bool mem_cgroup_disabled(void)
 403 {
 404         return true;
 405 }
 406
 407 static inline int
 408 mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
 409 {
 410         return 1;
 411 }
 412
 413 static inline unsigned long
 414 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 415 {
 416         return 0;
 417 }
 418
 419 static inline void
 420 mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 421                               int increment)
 422 {
 423 }
 424
 425 static inline void
 426 mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 427 {
 428 }
 429
 430 static inline void mem_cgroup_begin_update_page_stat(struct page *page,
 431                                         bool *locked, unsigned long *flags)
 432 {
 433 }
 434
 435 static inline void mem_cgroup_end_update_page_stat(struct page *page,
 436                                         bool *locked, unsigned long *flags)
 437 {
 438 }
 439
 440 static inline bool mem_cgroup_toggle_oom(bool new)
 441 {
 442         return false;
 443 }
 444
 445 static inline void mem_cgroup_enable_oom(void)
 446 {
 447 }
 448
 449 static inline void mem_cgroup_disable_oom(void)
 450 {
 451 }
 452
 453 static inline bool task_in_memcg_oom(struct task_struct *p)
 454 {
 455         return false;
 456 }
 457
 458 static inline bool mem_cgroup_oom_synchronize(void)
 459 {
 460         return false;
 461 }
 462
 463 static inline void mem_cgroup_inc_page_stat(struct page *page,
 464                                             enum mem_cgroup_stat_index idx)
 465 {
 466 }
 467
 468 static inline void mem_cgroup_dec_page_stat(struct page *page,
 469                                             enum mem_cgroup_stat_index idx)
 470 {
 471 }
 472
 473 static inline
 474 enum mem_cgroup_filter_t
 475 mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
 476                 struct mem_cgroup *root)
 477 {
 478         return VISIT;
 479 }
 480
 481 static inline void mem_cgroup_split_huge_fixup(struct page *head)
 482 {
 483 }
 484
 485 static inline
 486 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 487 {
 488 }
 489 static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
 490                                 struct page *newpage)
 491 {
 492 }
 493 #endif /* CONFIG_MEMCG */
 494
 495 #if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM)
 496 static inline bool
 497 mem_cgroup_bad_page_check(struct page *page)
 498 {
 499         return false;
 500 }
 501
 502 static inline void
 503 mem_cgroup_print_bad_page(struct page *page)
 504 {
 505 }
 506 #endif
 507
 508 enum {
 509         UNDER_LIMIT,
 510         SOFT_LIMIT,
 511         OVER_LIMIT,
 512 };
 513
 514 struct sock;
 515 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
 516 void sock_update_memcg(struct sock *sk);
 517 void sock_release_memcg(struct sock *sk);
 518 #else
 519 static inline void sock_update_memcg(struct sock *sk)
 520 {
 521 }
 522 static inline void sock_release_memcg(struct sock *sk)
 523 {
 524 }
 525 #endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */
 526
 527 #ifdef CONFIG_MEMCG_KMEM
 528 extern struct static_key memcg_kmem_enabled_key;
 529
 530 extern int memcg_limited_groups_array_size;
 531
 532 /*
 533  * Helper macro to loop through all memcg-specific caches. Callers must still
 534  * check if the cache is valid (it is either valid or NULL).
 535  * the slab_mutex must be held when looping through those caches
 536  */
 537 #define for_each_memcg_cache_index(_idx)        \
 538         for ((_idx) = 0; (_idx) < memcg_limited_groups_array_size; (_idx)++)
 539
 540 static inline bool memcg_kmem_enabled(void)
 541 {
 542         return static_key_false(&memcg_kmem_enabled_key);
 543 }
 544
 545 /*
 546  * In general, we'll do everything in our power to not incur in any overhead
 547  * for non-memcg users for the kmem functions. Not even a function call, if we
 548  * can avoid it.
 549  *
 550  * Therefore, we'll inline all those functions so that in the best case, we'll
 551  * see that kmemcg is off for everybody and proceed quickly.  If it is on,
 552  * we'll still do most of the flag checking inline. We check a lot of
 553  * conditions, but because they are pretty simple, they are expected to be
 554  * fast.
 555  */
 556 bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg,
 557                                         int order);
 558 void __memcg_kmem_commit_charge(struct page *page,
 559                                        struct mem_cgroup *memcg, int order);
 560 void __memcg_kmem_uncharge_pages(struct page *page, int order);
 561
 562 int memcg_cache_id(struct mem_cgroup *memcg);
 563 int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
 564                          struct kmem_cache *root_cache);
 565 void memcg_release_cache(struct kmem_cache *cachep);
 566 void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep);
 567
 568 int memcg_update_cache_size(struct kmem_cache *s, int num_groups);
 569 void memcg_update_array_size(int num_groups);
 570
 571 struct kmem_cache *
 572 __memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
 573
 574 void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
 575 void kmem_cache_destroy_memcg_children(struct kmem_cache *s);
 576
 577 /**
 578  * memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
 579  * @gfp: the gfp allocation flags.
 580  * @memcg: a pointer to the memcg this was charged against.
 581  * @order: allocation order.
 582  *
 583  * returns true if the memcg where the current task belongs can hold this
 584  * allocation.
 585  *
 586  * We return true automatically if this allocation is not to be accounted to
 587  * any memcg.
 588  */
 589 static inline bool
 590 memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
 591 {
 592         if (!memcg_kmem_enabled())
 593                 return true;
 594
 595         /*
 596          * __GFP_NOFAIL allocations will move on even if charging is not
 597          * possible. Therefore we don't even try, and have this allocation
 598          * unaccounted. We could in theory charge it with
 599          * res_counter_charge_nofail, but we hope those allocations are rare,
 600          * and won't be worth the trouble.
 601          */
 602         if (!(gfp & __GFP_KMEMCG) || (gfp & __GFP_NOFAIL))
 603                 return true;
 604         if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
 605                 return true;
 606
 607         /* If the test is dying, just let it go. */
 608         if (unlikely(fatal_signal_pending(current)))
 609                 return true;
 610
 611         return __memcg_kmem_newpage_charge(gfp, memcg, order);
 612 }
 613
 614 /**
 615  * memcg_kmem_uncharge_pages: uncharge pages from memcg
 616  * @page: pointer to struct page being freed
 617  * @order: allocation order.
 618  *
 619  * there is no need to specify memcg here, since it is embedded in page_cgroup
 620  */
 621 static inline void
 622 memcg_kmem_uncharge_pages(struct page *page, int order)
 623 {
 624         if (memcg_kmem_enabled())
 625                 __memcg_kmem_uncharge_pages(page, order);
 626 }
 627
 628 /**
 629  * memcg_kmem_commit_charge: embeds correct memcg in a page
 630  * @page: pointer to struct page recently allocated
 631  * @memcg: the memcg structure we charged against
 632  * @order: allocation order.
 633  *
 634  * Needs to be called after memcg_kmem_newpage_charge, regardless of success or
 635  * failure of the allocation. if @page is NULL, this function will revert the
 636  * charges. Otherwise, it will commit the memcg given by @memcg to the
 637  * corresponding page_cgroup.
 638  */
 639 static inline void
 640 memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
 641 {
 642         if (memcg_kmem_enabled() && memcg)
 643                 __memcg_kmem_commit_charge(page, memcg, order);
 644 }
 645
 646 /**
 647  * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
 648  * @cachep: the original global kmem cache
 649  * @gfp: allocation flags.
 650  *
 651  * This function assumes that the task allocating, which determines the memcg
 652  * in the page allocator, belongs to the same cgroup throughout the whole
 653  * process.  Misacounting can happen if the task calls memcg_kmem_get_cache()
 654  * while belonging to a cgroup, and later on changes. This is considered
 655  * acceptable, and should only happen upon task migration.
 656  *
 657  * Before the cache is created by the memcg core, there is also a possible
 658  * imbalance: the task belongs to a memcg, but the cache being allocated from
 659  * is the global cache, since the child cache is not yet guaranteed to be
 660  * ready. This case is also fine, since in this case the GFP_KMEMCG will not be
 661  * passed and the page allocator will not attempt any cgroup accounting.
 662  */
 663 static __always_inline struct kmem_cache *
 664 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 665 {
 666         if (!memcg_kmem_enabled())
 667                 return cachep;
 668         if (gfp & __GFP_NOFAIL)
 669                 return cachep;
 670         if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
 671                 return cachep;
 672         if (unlikely(fatal_signal_pending(current)))
 673                 return cachep;
 674
 675         return __memcg_kmem_get_cache(cachep, gfp);
 676 }
 677 #else
 678 #define for_each_memcg_cache_index(_idx)        \
 679         for (; NULL; )
 680
 681 static inline bool memcg_kmem_enabled(void)
 682 {
 683         return false;
 684 }
 685
 686 static inline bool
 687 memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
 688 {
 689         return true;
 690 }
 691
 692 static inline void memcg_kmem_uncharge_pages(struct page *page, int order)
 693 {
 694 }
 695
 696 static inline void
 697 memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
 698 {
 699 }
 700
 701 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 702 {
 703         return -1;
 704 }
 705
 706 static inline int
 707 memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
 708                      struct kmem_cache *root_cache)
 709 {
 710         return 0;
 711 }
 712
 713 static inline void memcg_release_cache(struct kmem_cache *cachep)
 714 {
 715 }
 716
 717 static inline void memcg_cache_list_add(struct mem_cgroup *memcg,
 718                                         struct kmem_cache *s)
 719 {
 720 }
 721
 722 static inline struct kmem_cache *
 723 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 724 {
 725         return cachep;
 726 }
 727
 728 static inline void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
 729 {
 730 }
 731 #endif /* CONFIG_MEMCG_KMEM */
 732 #endif /* _LINUX_MEMCONTROL_H */
 733