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 /**
 141  * mem_cgroup_toggle_oom - toggle the memcg OOM killer for the current task
 142  * @new: true to enable, false to disable
 143  *
 144  * Toggle whether a failed memcg charge should invoke the OOM killer
 145  * or just return -ENOMEM.  Returns the previous toggle state.
 146  *
 147  * NOTE: Any path that enables the OOM killer before charging must
 148  *       call mem_cgroup_oom_synchronize() afterward to finalize the
 149  *       OOM handling and clean up.
 150  */
 151 static inline bool mem_cgroup_toggle_oom(bool new)
 152 {
 153         bool old;
 154
 155         old = current->memcg_oom.may_oom;
 156         current->memcg_oom.may_oom = new;
 157
 158         return old;
 159 }
 160
 161 static inline void mem_cgroup_enable_oom(void)
 162 {
 163         bool old = mem_cgroup_toggle_oom(true);
 164
 165         WARN_ON(old == true);
 166 }
 167
 168 static inline void mem_cgroup_disable_oom(void)
 169 {
 170         bool old = mem_cgroup_toggle_oom(false);
 171
 172         WARN_ON(old == false);
 173 }
 174
 175 static inline bool task_in_memcg_oom(struct task_struct *p)
 176 {
 177         return p->memcg_oom.in_memcg_oom;
 178 }
 179
 180 bool mem_cgroup_oom_synchronize(void);
 181
 182 #ifdef CONFIG_MEMCG_SWAP
 183 extern int do_swap_account;
 184 #endif
 185
 186 static inline bool mem_cgroup_disabled(void)
 187 {
 188         if (mem_cgroup_subsys.disabled)
 189                 return true;
 190         return false;
 191 }
 192
 193 void __mem_cgroup_begin_update_page_stat(struct page *page, bool *locked,
 194                                          unsigned long *flags);
 195
 196 extern atomic_t memcg_moving;
 197
 198 static inline void mem_cgroup_begin_update_page_stat(struct page *page,
 199                                         bool *locked, unsigned long *flags)
 200 {
 201         if (mem_cgroup_disabled())
 202                 return;
 203         rcu_read_lock();
 204         *locked = false;
 205         if (atomic_read(&memcg_moving))
 206                 __mem_cgroup_begin_update_page_stat(page, locked, flags);
 207 }
 208
 209 void __mem_cgroup_end_update_page_stat(struct page *page,
 210                                 unsigned long *flags);
 211 static inline void mem_cgroup_end_update_page_stat(struct page *page,
 212                                         bool *locked, unsigned long *flags)
 213 {
 214         if (mem_cgroup_disabled())
 215                 return;
 216         if (*locked)
 217                 __mem_cgroup_end_update_page_stat(page, flags);
 218         rcu_read_unlock();
 219 }
 220
 221 void mem_cgroup_update_page_stat(struct page *page,
 222                                  enum mem_cgroup_stat_index idx,
 223                                  int val);
 224
 225 static inline void mem_cgroup_inc_page_stat(struct page *page,
 226                                             enum mem_cgroup_stat_index idx)
 227 {
 228         mem_cgroup_update_page_stat(page, idx, 1);
 229 }
 230
 231 static inline void mem_cgroup_dec_page_stat(struct page *page,
 232                                             enum mem_cgroup_stat_index idx)
 233 {
 234         mem_cgroup_update_page_stat(page, idx, -1);
 235 }
 236
 237 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 238                                                 gfp_t gfp_mask,
 239                                                 unsigned long *total_scanned);
 240
 241 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx);
 242 static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
 243                                              enum vm_event_item idx)
 244 {
 245         if (mem_cgroup_disabled())
 246                 return;
 247         __mem_cgroup_count_vm_event(mm, idx);
 248 }
 249 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 250 void mem_cgroup_split_huge_fixup(struct page *head);
 251 #endif
 252
 253 #ifdef CONFIG_DEBUG_VM
 254 bool mem_cgroup_bad_page_check(struct page *page);
 255 void mem_cgroup_print_bad_page(struct page *page);
 256 #endif
 257 #else /* CONFIG_MEMCG */
 258 struct mem_cgroup;
 259
 260 static inline int mem_cgroup_newpage_charge(struct page *page,
 261                                         struct mm_struct *mm, gfp_t gfp_mask)
 262 {
 263         return 0;
 264 }
 265
 266 static inline int mem_cgroup_cache_charge(struct page *page,
 267                                         struct mm_struct *mm, gfp_t gfp_mask)
 268 {
 269         return 0;
 270 }
 271
 272 static inline int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
 273                 struct page *page, gfp_t gfp_mask, struct mem_cgroup **memcgp)
 274 {
 275         return 0;
 276 }
 277
 278 static inline void mem_cgroup_commit_charge_swapin(struct page *page,
 279                                           struct mem_cgroup *memcg)
 280 {
 281 }
 282
 283 static inline void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
 284 {
 285 }
 286
 287 static inline void mem_cgroup_uncharge_start(void)
 288 {
 289 }
 290
 291 static inline void mem_cgroup_uncharge_end(void)
 292 {
 293 }
 294
 295 static inline void mem_cgroup_uncharge_page(struct page *page)
 296 {
 297 }
 298
 299 static inline void mem_cgroup_uncharge_cache_page(struct page *page)
 300 {
 301 }
 302
 303 static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
 304                                                     struct mem_cgroup *memcg)
 305 {
 306         return &zone->lruvec;
 307 }
 308
 309 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 310                                                     struct zone *zone)
 311 {
 312         return &zone->lruvec;
 313 }
 314
 315 static inline struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
 316 {
 317         return NULL;
 318 }
 319
 320 static inline struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
 321 {
 322         return NULL;
 323 }
 324
 325 static inline bool mm_match_cgroup(struct mm_struct *mm,
 326                 struct mem_cgroup *memcg)
 327 {
 328         return true;
 329 }
 330
 331 static inline bool task_in_mem_cgroup(struct task_struct *task,
 332                                       const struct mem_cgroup *memcg)
 333 {
 334         return true;
 335 }
 336
 337 static inline struct cgroup_subsys_state
 338                 *mem_cgroup_css(struct mem_cgroup *memcg)
 339 {
 340         return NULL;
 341 }
 342
 343 static inline void
 344 mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
 345                              struct mem_cgroup **memcgp)
 346 {
 347 }
 348
 349 static inline void mem_cgroup_end_migration(struct mem_cgroup *memcg,
 350                 struct page *oldpage, struct page *newpage, bool migration_ok)
 351 {
 352 }
 353
 354 static inline struct mem_cgroup *
 355 mem_cgroup_iter(struct mem_cgroup *root,
 356                 struct mem_cgroup *prev,
 357                 struct mem_cgroup_reclaim_cookie *reclaim)
 358 {
 359         return NULL;
 360 }
 361
 362 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 363                                          struct mem_cgroup *prev)
 364 {
 365 }
 366
 367 static inline bool mem_cgroup_disabled(void)
 368 {
 369         return true;
 370 }
 371
 372 static inline int
 373 mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
 374 {
 375         return 1;
 376 }
 377
 378 static inline unsigned long
 379 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 380 {
 381         return 0;
 382 }
 383
 384 static inline void
 385 mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 386                               int increment)
 387 {
 388 }
 389
 390 static inline void
 391 mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 392 {
 393 }
 394
 395 static inline void mem_cgroup_begin_update_page_stat(struct page *page,
 396                                         bool *locked, unsigned long *flags)
 397 {
 398 }
 399
 400 static inline void mem_cgroup_end_update_page_stat(struct page *page,
 401                                         bool *locked, unsigned long *flags)
 402 {
 403 }
 404
 405 static inline bool mem_cgroup_toggle_oom(bool new)
 406 {
 407         return false;
 408 }
 409
 410 static inline void mem_cgroup_enable_oom(void)
 411 {
 412 }
 413
 414 static inline void mem_cgroup_disable_oom(void)
 415 {
 416 }
 417
 418 static inline bool task_in_memcg_oom(struct task_struct *p)
 419 {
 420         return false;
 421 }
 422
 423 static inline bool mem_cgroup_oom_synchronize(void)
 424 {
 425         return false;
 426 }
 427
 428 static inline void mem_cgroup_inc_page_stat(struct page *page,
 429                                             enum mem_cgroup_stat_index idx)
 430 {
 431 }
 432
 433 static inline void mem_cgroup_dec_page_stat(struct page *page,
 434                                             enum mem_cgroup_stat_index idx)
 435 {
 436 }
 437
 438 static inline
 439 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 440                                             gfp_t gfp_mask,
 441                                             unsigned long *total_scanned)
 442 {
 443         return 0;
 444 }
 445
 446 static inline void mem_cgroup_split_huge_fixup(struct page *head)
 447 {
 448 }
 449
 450 static inline
 451 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 452 {
 453 }
 454 static inline void mem_cgroup_replace_page_cache(struct page *oldpage,
 455                                 struct page *newpage)
 456 {
 457 }
 458 #endif /* CONFIG_MEMCG */
 459
 460 #if !defined(CONFIG_MEMCG) || !defined(CONFIG_DEBUG_VM)
 461 static inline bool
 462 mem_cgroup_bad_page_check(struct page *page)
 463 {
 464         return false;
 465 }
 466
 467 static inline void
 468 mem_cgroup_print_bad_page(struct page *page)
 469 {
 470 }
 471 #endif
 472
 473 enum {
 474         UNDER_LIMIT,
 475         SOFT_LIMIT,
 476         OVER_LIMIT,
 477 };
 478
 479 struct sock;
 480 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
 481 void sock_update_memcg(struct sock *sk);
 482 void sock_release_memcg(struct sock *sk);
 483 #else
 484 static inline void sock_update_memcg(struct sock *sk)
 485 {
 486 }
 487 static inline void sock_release_memcg(struct sock *sk)
 488 {
 489 }
 490 #endif /* CONFIG_INET && CONFIG_MEMCG_KMEM */
 491
 492 #ifdef CONFIG_MEMCG_KMEM
 493 extern struct static_key memcg_kmem_enabled_key;
 494
 495 extern int memcg_limited_groups_array_size;
 496
 497 /*
 498  * Helper macro to loop through all memcg-specific caches. Callers must still
 499  * check if the cache is valid (it is either valid or NULL).
 500  * the slab_mutex must be held when looping through those caches
 501  */
 502 #define for_each_memcg_cache_index(_idx)        \
 503         for ((_idx) = 0; (_idx) < memcg_limited_groups_array_size; (_idx)++)
 504
 505 static inline bool memcg_kmem_enabled(void)
 506 {
 507         return static_key_false(&memcg_kmem_enabled_key);
 508 }
 509
 510 /*
 511  * In general, we'll do everything in our power to not incur in any overhead
 512  * for non-memcg users for the kmem functions. Not even a function call, if we
 513  * can avoid it.
 514  *
 515  * Therefore, we'll inline all those functions so that in the best case, we'll
 516  * see that kmemcg is off for everybody and proceed quickly.  If it is on,
 517  * we'll still do most of the flag checking inline. We check a lot of
 518  * conditions, but because they are pretty simple, they are expected to be
 519  * fast.
 520  */
 521 bool __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg,
 522                                         int order);
 523 void __memcg_kmem_commit_charge(struct page *page,
 524                                        struct mem_cgroup *memcg, int order);
 525 void __memcg_kmem_uncharge_pages(struct page *page, int order);
 526
 527 int memcg_cache_id(struct mem_cgroup *memcg);
 528 int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
 529                          struct kmem_cache *root_cache);
 530 void memcg_release_cache(struct kmem_cache *cachep);
 531 void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep);
 532
 533 int memcg_update_cache_size(struct kmem_cache *s, int num_groups);
 534 void memcg_update_array_size(int num_groups);
 535
 536 struct kmem_cache *
 537 __memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
 538
 539 void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
 540 void kmem_cache_destroy_memcg_children(struct kmem_cache *s);
 541
 542 /**
 543  * memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
 544  * @gfp: the gfp allocation flags.
 545  * @memcg: a pointer to the memcg this was charged against.
 546  * @order: allocation order.
 547  *
 548  * returns true if the memcg where the current task belongs can hold this
 549  * allocation.
 550  *
 551  * We return true automatically if this allocation is not to be accounted to
 552  * any memcg.
 553  */
 554 static inline bool
 555 memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
 556 {
 557         if (!memcg_kmem_enabled())
 558                 return true;
 559
 560         /*
 561          * __GFP_NOFAIL allocations will move on even if charging is not
 562          * possible. Therefore we don't even try, and have this allocation
 563          * unaccounted. We could in theory charge it with
 564          * res_counter_charge_nofail, but we hope those allocations are rare,
 565          * and won't be worth the trouble.
 566          */
 567         if (!(gfp & __GFP_KMEMCG) || (gfp & __GFP_NOFAIL))
 568                 return true;
 569         if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
 570                 return true;
 571
 572         /* If the test is dying, just let it go. */
 573         if (unlikely(fatal_signal_pending(current)))
 574                 return true;
 575
 576         return __memcg_kmem_newpage_charge(gfp, memcg, order);
 577 }
 578
 579 /**
 580  * memcg_kmem_uncharge_pages: uncharge pages from memcg
 581  * @page: pointer to struct page being freed
 582  * @order: allocation order.
 583  *
 584  * there is no need to specify memcg here, since it is embedded in page_cgroup
 585  */
 586 static inline void
 587 memcg_kmem_uncharge_pages(struct page *page, int order)
 588 {
 589         if (memcg_kmem_enabled())
 590                 __memcg_kmem_uncharge_pages(page, order);
 591 }
 592
 593 /**
 594  * memcg_kmem_commit_charge: embeds correct memcg in a page
 595  * @page: pointer to struct page recently allocated
 596  * @memcg: the memcg structure we charged against
 597  * @order: allocation order.
 598  *
 599  * Needs to be called after memcg_kmem_newpage_charge, regardless of success or
 600  * failure of the allocation. if @page is NULL, this function will revert the
 601  * charges. Otherwise, it will commit the memcg given by @memcg to the
 602  * corresponding page_cgroup.
 603  */
 604 static inline void
 605 memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
 606 {
 607         if (memcg_kmem_enabled() && memcg)
 608                 __memcg_kmem_commit_charge(page, memcg, order);
 609 }
 610
 611 /**
 612  * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
 613  * @cachep: the original global kmem cache
 614  * @gfp: allocation flags.
 615  *
 616  * This function assumes that the task allocating, which determines the memcg
 617  * in the page allocator, belongs to the same cgroup throughout the whole
 618  * process.  Misacounting can happen if the task calls memcg_kmem_get_cache()
 619  * while belonging to a cgroup, and later on changes. This is considered
 620  * acceptable, and should only happen upon task migration.
 621  *
 622  * Before the cache is created by the memcg core, there is also a possible
 623  * imbalance: the task belongs to a memcg, but the cache being allocated from
 624  * is the global cache, since the child cache is not yet guaranteed to be
 625  * ready. This case is also fine, since in this case the GFP_KMEMCG will not be
 626  * passed and the page allocator will not attempt any cgroup accounting.
 627  */
 628 static __always_inline struct kmem_cache *
 629 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 630 {
 631         if (!memcg_kmem_enabled())
 632                 return cachep;
 633         if (gfp & __GFP_NOFAIL)
 634                 return cachep;
 635         if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
 636                 return cachep;
 637         if (unlikely(fatal_signal_pending(current)))
 638                 return cachep;
 639
 640         return __memcg_kmem_get_cache(cachep, gfp);
 641 }
 642 #else
 643 #define for_each_memcg_cache_index(_idx)        \
 644         for (; NULL; )
 645
 646 static inline bool memcg_kmem_enabled(void)
 647 {
 648         return false;
 649 }
 650
 651 static inline bool
 652 memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **memcg, int order)
 653 {
 654         return true;
 655 }
 656
 657 static inline void memcg_kmem_uncharge_pages(struct page *page, int order)
 658 {
 659 }
 660
 661 static inline void
 662 memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg, int order)
 663 {
 664 }
 665
 666 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 667 {
 668         return -1;
 669 }
 670
 671 static inline int
 672 memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
 673                      struct kmem_cache *root_cache)
 674 {
 675         return 0;
 676 }
 677
 678 static inline void memcg_release_cache(struct kmem_cache *cachep)
 679 {
 680 }
 681
 682 static inline void memcg_cache_list_add(struct mem_cgroup *memcg,
 683                                         struct kmem_cache *s)
 684 {
 685 }
 686
 687 static inline struct kmem_cache *
 688 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 689 {
 690         return cachep;
 691 }
 692
 693 static inline void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
 694 {
 695 }
 696 #endif /* CONFIG_MEMCG_KMEM */
 697 #endif /* _LINUX_MEMCONTROL_H */
 698