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