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 #include <linux/page_counter.h>
  27 #include <linux/vmpressure.h>
  28 #include <linux/eventfd.h>
  29 #include <linux/mmzone.h>
  30 #include <linux/writeback.h>
  31 #include <linux/page-flags.h>
  32
  33 struct mem_cgroup;
  34 struct page;
  35 struct mm_struct;
  36 struct kmem_cache;
  37
  38 /*
  39  * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
  40  * These two lists should keep in accord with each other.
  41  */
  42 enum mem_cgroup_stat_index {
  43         /*
  44          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
  45          */
  46         MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
  47         MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
  48         MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
  49         MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
  50         MEM_CGROUP_STAT_DIRTY,          /* # of dirty pages in page cache */
  51         MEM_CGROUP_STAT_WRITEBACK,      /* # of pages under writeback */
  52         MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
  53         MEM_CGROUP_STAT_NSTATS,
  54         /* default hierarchy stats */
  55         MEMCG_KERNEL_STACK_KB = MEM_CGROUP_STAT_NSTATS,
  56         MEMCG_SLAB_RECLAIMABLE,
  57         MEMCG_SLAB_UNRECLAIMABLE,
  58         MEMCG_SOCK,
  59         MEMCG_NR_STAT,
  60 };
  61
  62 struct mem_cgroup_reclaim_cookie {
  63         pg_data_t *pgdat;
  64         int priority;
  65         unsigned int generation;
  66 };
  67
  68 enum mem_cgroup_events_index {
  69         MEM_CGROUP_EVENTS_PGPGIN,       /* # of pages paged in */
  70         MEM_CGROUP_EVENTS_PGPGOUT,      /* # of pages paged out */
  71         MEM_CGROUP_EVENTS_PGFAULT,      /* # of page-faults */
  72         MEM_CGROUP_EVENTS_PGMAJFAULT,   /* # of major page-faults */
  73         MEM_CGROUP_EVENTS_NSTATS,
  74         /* default hierarchy events */
  75         MEMCG_LOW = MEM_CGROUP_EVENTS_NSTATS,
  76         MEMCG_HIGH,
  77         MEMCG_MAX,
  78         MEMCG_OOM,
  79         MEMCG_NR_EVENTS,
  80 };
  81
  82 /*
  83  * Per memcg event counter is incremented at every pagein/pageout. With THP,
  84  * it will be incremated by the number of pages. This counter is used for
  85  * for trigger some periodic events. This is straightforward and better
  86  * than using jiffies etc. to handle periodic memcg event.
  87  */
  88 enum mem_cgroup_events_target {
  89         MEM_CGROUP_TARGET_THRESH,
  90         MEM_CGROUP_TARGET_SOFTLIMIT,
  91         MEM_CGROUP_TARGET_NUMAINFO,
  92         MEM_CGROUP_NTARGETS,
  93 };
  94
  95 #ifdef CONFIG_MEMCG
  96
  97 #define MEM_CGROUP_ID_SHIFT     16
  98 #define MEM_CGROUP_ID_MAX       USHRT_MAX
  99
 100 struct mem_cgroup_id {
 101         int id;
 102         atomic_t ref;
 103 };
 104
 105 struct mem_cgroup_stat_cpu {
 106         long count[MEMCG_NR_STAT];
 107         unsigned long events[MEMCG_NR_EVENTS];
 108         unsigned long nr_page_events;
 109         unsigned long targets[MEM_CGROUP_NTARGETS];
 110 };
 111
 112 struct mem_cgroup_reclaim_iter {
 113         struct mem_cgroup *position;
 114         /* scan generation, increased every round-trip */
 115         unsigned int generation;
 116 };
 117
 118 /*
 119  * per-zone information in memory controller.
 120  */
 121 struct mem_cgroup_per_node {
 122         struct lruvec           lruvec;
 123         unsigned long           lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];
 124
 125         struct mem_cgroup_reclaim_iter  iter[DEF_PRIORITY + 1];
 126
 127         struct rb_node          tree_node;      /* RB tree node */
 128         unsigned long           usage_in_excess;/* Set to the value by which */
 129                                                 /* the soft limit is exceeded*/
 130         bool                    on_tree;
 131         struct mem_cgroup       *memcg;         /* Back pointer, we cannot */
 132                                                 /* use container_of        */
 133 };
 134
 135 struct mem_cgroup_threshold {
 136         struct eventfd_ctx *eventfd;
 137         unsigned long threshold;
 138 };
 139
 140 /* For threshold */
 141 struct mem_cgroup_threshold_ary {
 142         /* An array index points to threshold just below or equal to usage. */
 143         int current_threshold;
 144         /* Size of entries[] */
 145         unsigned int size;
 146         /* Array of thresholds */
 147         struct mem_cgroup_threshold entries[0];
 148 };
 149
 150 struct mem_cgroup_thresholds {
 151         /* Primary thresholds array */
 152         struct mem_cgroup_threshold_ary *primary;
 153         /*
 154          * Spare threshold array.
 155          * This is needed to make mem_cgroup_unregister_event() "never fail".
 156          * It must be able to store at least primary->size - 1 entries.
 157          */
 158         struct mem_cgroup_threshold_ary *spare;
 159 };
 160
 161 enum memcg_kmem_state {
 162         KMEM_NONE,
 163         KMEM_ALLOCATED,
 164         KMEM_ONLINE,
 165 };
 166
 167 /*
 168  * The memory controller data structure. The memory controller controls both
 169  * page cache and RSS per cgroup. We would eventually like to provide
 170  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 171  * to help the administrator determine what knobs to tune.
 172  */
 173 struct mem_cgroup {
 174         struct cgroup_subsys_state css;
 175
 176         /* Private memcg ID. Used to ID objects that outlive the cgroup */
 177         struct mem_cgroup_id id;
 178
 179         /* Accounted resources */
 180         struct page_counter memory;
 181         struct page_counter swap;
 182
 183         /* Legacy consumer-oriented counters */
 184         struct page_counter memsw;
 185         struct page_counter kmem;
 186         struct page_counter tcpmem;
 187
 188         /* Normal memory consumption range */
 189         unsigned long low;
 190         unsigned long high;
 191
 192         /* Range enforcement for interrupt charges */
 193         struct work_struct high_work;
 194
 195         unsigned long soft_limit;
 196
 197         /* vmpressure notifications */
 198         struct vmpressure vmpressure;
 199
 200         /*
 201          * Should the accounting and control be hierarchical, per subtree?
 202          */
 203         bool use_hierarchy;
 204
 205         /* protected by memcg_oom_lock */
 206         bool            oom_lock;
 207         int             under_oom;
 208
 209         int     swappiness;
 210         /* OOM-Killer disable */
 211         int             oom_kill_disable;
 212
 213         /* handle for "memory.events" */
 214         struct cgroup_file events_file;
 215
 216         /* protect arrays of thresholds */
 217         struct mutex thresholds_lock;
 218
 219         /* thresholds for memory usage. RCU-protected */
 220         struct mem_cgroup_thresholds thresholds;
 221
 222         /* thresholds for mem+swap usage. RCU-protected */
 223         struct mem_cgroup_thresholds memsw_thresholds;
 224
 225         /* For oom notifier event fd */
 226         struct list_head oom_notify;
 227
 228         /*
 229          * Should we move charges of a task when a task is moved into this
 230          * mem_cgroup ? And what type of charges should we move ?
 231          */
 232         unsigned long move_charge_at_immigrate;
 233         /*
 234          * set > 0 if pages under this cgroup are moving to other cgroup.
 235          */
 236         atomic_t                moving_account;
 237         /* taken only while moving_account > 0 */
 238         spinlock_t              move_lock;
 239         struct task_struct      *move_lock_task;
 240         unsigned long           move_lock_flags;
 241         /*
 242          * percpu counter.
 243          */
 244         struct mem_cgroup_stat_cpu __percpu *stat;
 245
 246         unsigned long           socket_pressure;
 247
 248         /* Legacy tcp memory accounting */
 249         bool                    tcpmem_active;
 250         int                     tcpmem_pressure;
 251
 252 #ifndef CONFIG_SLOB
 253         /* Index in the kmem_cache->memcg_params.memcg_caches array */
 254         int kmemcg_id;
 255         enum memcg_kmem_state kmem_state;
 256 #endif
 257
 258         int last_scanned_node;
 259 #if MAX_NUMNODES > 1
 260         nodemask_t      scan_nodes;
 261         atomic_t        numainfo_events;
 262         atomic_t        numainfo_updating;
 263 #endif
 264
 265 #ifdef CONFIG_CGROUP_WRITEBACK
 266         struct list_head cgwb_list;
 267         struct wb_domain cgwb_domain;
 268 #endif
 269
 270         /* List of events which userspace want to receive */
 271         struct list_head event_list;
 272         spinlock_t event_list_lock;
 273
 274         struct mem_cgroup_per_node *nodeinfo[0];
 275         /* WARNING: nodeinfo must be the last member here */
 276 };
 277
 278 extern struct mem_cgroup *root_mem_cgroup;
 279
 280 static inline bool mem_cgroup_disabled(void)
 281 {
 282         return !cgroup_subsys_enabled(memory_cgrp_subsys);
 283 }
 284
 285 /**
 286  * mem_cgroup_events - count memory events against a cgroup
 287  * @memcg: the memory cgroup
 288  * @idx: the event index
 289  * @nr: the number of events to account for
 290  */
 291 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 292                        enum mem_cgroup_events_index idx,
 293                        unsigned int nr)
 294 {
 295         this_cpu_add(memcg->stat->events[idx], nr);
 296         cgroup_file_notify(&memcg->events_file);
 297 }
 298
 299 bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);
 300
 301 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 302                           gfp_t gfp_mask, struct mem_cgroup **memcgp,
 303                           bool compound);
 304 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
 305                               bool lrucare, bool compound);
 306 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
 307                 bool compound);
 308 void mem_cgroup_uncharge(struct page *page);
 309 void mem_cgroup_uncharge_list(struct list_head *page_list);
 310
 311 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
 312
 313 static struct mem_cgroup_per_node *
 314 mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
 315 {
 316         return memcg->nodeinfo[nid];
 317 }
 318
 319 /**
 320  * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
 321  * @node: node of the wanted lruvec
 322  * @memcg: memcg of the wanted lruvec
 323  *
 324  * Returns the lru list vector holding pages for a given @node or a given
 325  * @memcg and @zone. This can be the node lruvec, if the memory controller
 326  * is disabled.
 327  */
 328 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
 329                                 struct mem_cgroup *memcg)
 330 {
 331         struct mem_cgroup_per_node *mz;
 332         struct lruvec *lruvec;
 333
 334         if (mem_cgroup_disabled()) {
 335                 lruvec = node_lruvec(pgdat);
 336                 goto out;
 337         }
 338
 339         mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
 340         lruvec = &mz->lruvec;
 341 out:
 342         /*
 343          * Since a node can be onlined after the mem_cgroup was created,
 344          * we have to be prepared to initialize lruvec->pgdat here;
 345          * and if offlined then reonlined, we need to reinitialize it.
 346          */
 347         if (unlikely(lruvec->pgdat != pgdat))
 348                 lruvec->pgdat = pgdat;
 349         return lruvec;
 350 }
 351
 352 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
 353
 354 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
 355 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 356
 357 static inline
 358 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 359         return css ? container_of(css, struct mem_cgroup, css) : NULL;
 360 }
 361
 362 #define mem_cgroup_from_counter(counter, member)        \
 363         container_of(counter, struct mem_cgroup, member)
 364
 365 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
 366                                    struct mem_cgroup *,
 367                                    struct mem_cgroup_reclaim_cookie *);
 368 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
 369 int mem_cgroup_scan_tasks(struct mem_cgroup *,
 370                           int (*)(struct task_struct *, void *), void *);
 371
 372 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 373 {
 374         if (mem_cgroup_disabled())
 375                 return 0;
 376
 377         return memcg->id.id;
 378 }
 379 struct mem_cgroup *mem_cgroup_from_id(unsigned short id);
 380
 381 /**
 382  * parent_mem_cgroup - find the accounting parent of a memcg
 383  * @memcg: memcg whose parent to find
 384  *
 385  * Returns the parent memcg, or NULL if this is the root or the memory
 386  * controller is in legacy no-hierarchy mode.
 387  */
 388 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 389 {
 390         if (!memcg->memory.parent)
 391                 return NULL;
 392         return mem_cgroup_from_counter(memcg->memory.parent, memory);
 393 }
 394
 395 static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
 396                               struct mem_cgroup *root)
 397 {
 398         if (root == memcg)
 399                 return true;
 400         if (!root->use_hierarchy)
 401                 return false;
 402         return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
 403 }
 404
 405 static inline bool mm_match_cgroup(struct mm_struct *mm,
 406                                    struct mem_cgroup *memcg)
 407 {
 408         struct mem_cgroup *task_memcg;
 409         bool match = false;
 410
 411         rcu_read_lock();
 412         task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 413         if (task_memcg)
 414                 match = mem_cgroup_is_descendant(task_memcg, memcg);
 415         rcu_read_unlock();
 416         return match;
 417 }
 418
 419 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
 420 ino_t page_cgroup_ino(struct page *page);
 421
 422 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 423 {
 424         if (mem_cgroup_disabled())
 425                 return true;
 426         return !!(memcg->css.flags & CSS_ONLINE);
 427 }
 428
 429 /*
 430  * For memory reclaim.
 431  */
 432 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
 433
 434 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 435                 int zid, int nr_pages);
 436
 437 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 438                                            int nid, unsigned int lru_mask);
 439
 440 static inline
 441 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 442 {
 443         struct mem_cgroup_per_node *mz;
 444         unsigned long nr_pages = 0;
 445         int zid;
 446
 447         mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 448         for (zid = 0; zid < MAX_NR_ZONES; zid++)
 449                 nr_pages += mz->lru_zone_size[zid][lru];
 450         return nr_pages;
 451 }
 452
 453 static inline
 454 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 455                 enum lru_list lru, int zone_idx)
 456 {
 457         struct mem_cgroup_per_node *mz;
 458
 459         mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 460         return mz->lru_zone_size[zone_idx][lru];
 461 }
 462
 463 void mem_cgroup_handle_over_high(void);
 464
 465 unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg);
 466
 467 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 468                                 struct task_struct *p);
 469
 470 static inline void mem_cgroup_oom_enable(void)
 471 {
 472         WARN_ON(current->memcg_may_oom);
 473         current->memcg_may_oom = 1;
 474 }
 475
 476 static inline void mem_cgroup_oom_disable(void)
 477 {
 478         WARN_ON(!current->memcg_may_oom);
 479         current->memcg_may_oom = 0;
 480 }
 481
 482 static inline bool task_in_memcg_oom(struct task_struct *p)
 483 {
 484         return p->memcg_in_oom;
 485 }
 486
 487 bool mem_cgroup_oom_synchronize(bool wait);
 488
 489 #ifdef CONFIG_MEMCG_SWAP
 490 extern int do_swap_account;
 491 #endif
 492
 493 void lock_page_memcg(struct page *page);
 494 void unlock_page_memcg(struct page *page);
 495
 496 /**
 497  * mem_cgroup_update_page_stat - update page state statistics
 498  * @page: the page
 499  * @idx: page state item to account
 500  * @val: number of pages (positive or negative)
 501  *
 502  * The @page must be locked or the caller must use lock_page_memcg()
 503  * to prevent double accounting when the page is concurrently being
 504  * moved to another memcg:
 505  *
 506  *   lock_page(page) or lock_page_memcg(page)
 507  *   if (TestClearPageState(page))
 508  *     mem_cgroup_update_page_stat(page, state, -1);
 509  *   unlock_page(page) or unlock_page_memcg(page)
 510  */
 511 static inline void mem_cgroup_update_page_stat(struct page *page,
 512                                  enum mem_cgroup_stat_index idx, int val)
 513 {
 514         VM_BUG_ON(!(rcu_read_lock_held() || PageLocked(page)));
 515
 516         if (page->mem_cgroup)
 517                 this_cpu_add(page->mem_cgroup->stat->count[idx], val);
 518 }
 519
 520 static inline void mem_cgroup_inc_page_stat(struct page *page,
 521                                             enum mem_cgroup_stat_index idx)
 522 {
 523         mem_cgroup_update_page_stat(page, idx, 1);
 524 }
 525
 526 static inline void mem_cgroup_dec_page_stat(struct page *page,
 527                                             enum mem_cgroup_stat_index idx)
 528 {
 529         mem_cgroup_update_page_stat(page, idx, -1);
 530 }
 531
 532 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 533                                                 gfp_t gfp_mask,
 534                                                 unsigned long *total_scanned);
 535
 536 static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
 537                                              enum vm_event_item idx)
 538 {
 539         struct mem_cgroup *memcg;
 540
 541         if (mem_cgroup_disabled())
 542                 return;
 543
 544         rcu_read_lock();
 545         memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 546         if (unlikely(!memcg))
 547                 goto out;
 548
 549         switch (idx) {
 550         case PGFAULT:
 551                 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
 552                 break;
 553         case PGMAJFAULT:
 554                 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
 555                 break;
 556         default:
 557                 BUG();
 558         }
 559 out:
 560         rcu_read_unlock();
 561 }
 562 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 563 void mem_cgroup_split_huge_fixup(struct page *head);
 564 #endif
 565
 566 #else /* CONFIG_MEMCG */
 567
 568 #define MEM_CGROUP_ID_SHIFT     0
 569 #define MEM_CGROUP_ID_MAX       0
 570
 571 struct mem_cgroup;
 572
 573 static inline bool mem_cgroup_disabled(void)
 574 {
 575         return true;
 576 }
 577
 578 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 579                                      enum mem_cgroup_events_index idx,
 580                                      unsigned int nr)
 581 {
 582 }
 583
 584 static inline bool mem_cgroup_low(struct mem_cgroup *root,
 585                                   struct mem_cgroup *memcg)
 586 {
 587         return false;
 588 }
 589
 590 static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 591                                         gfp_t gfp_mask,
 592                                         struct mem_cgroup **memcgp,
 593                                         bool compound)
 594 {
 595         *memcgp = NULL;
 596         return 0;
 597 }
 598
 599 static inline void mem_cgroup_commit_charge(struct page *page,
 600                                             struct mem_cgroup *memcg,
 601                                             bool lrucare, bool compound)
 602 {
 603 }
 604
 605 static inline void mem_cgroup_cancel_charge(struct page *page,
 606                                             struct mem_cgroup *memcg,
 607                                             bool compound)
 608 {
 609 }
 610
 611 static inline void mem_cgroup_uncharge(struct page *page)
 612 {
 613 }
 614
 615 static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
 616 {
 617 }
 618
 619 static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 620 {
 621 }
 622
 623 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
 624                                 struct mem_cgroup *memcg)
 625 {
 626         return node_lruvec(pgdat);
 627 }
 628
 629 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 630                                                     struct pglist_data *pgdat)
 631 {
 632         return &pgdat->lruvec;
 633 }
 634
 635 static inline bool mm_match_cgroup(struct mm_struct *mm,
 636                 struct mem_cgroup *memcg)
 637 {
 638         return true;
 639 }
 640
 641 static inline bool task_in_mem_cgroup(struct task_struct *task,
 642                                       const struct mem_cgroup *memcg)
 643 {
 644         return true;
 645 }
 646
 647 static inline struct mem_cgroup *
 648 mem_cgroup_iter(struct mem_cgroup *root,
 649                 struct mem_cgroup *prev,
 650                 struct mem_cgroup_reclaim_cookie *reclaim)
 651 {
 652         return NULL;
 653 }
 654
 655 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 656                                          struct mem_cgroup *prev)
 657 {
 658 }
 659
 660 static inline int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
 661                 int (*fn)(struct task_struct *, void *), void *arg)
 662 {
 663         return 0;
 664 }
 665
 666 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 667 {
 668         return 0;
 669 }
 670
 671 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 672 {
 673         WARN_ON_ONCE(id);
 674         /* XXX: This should always return root_mem_cgroup */
 675         return NULL;
 676 }
 677
 678 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 679 {
 680         return true;
 681 }
 682
 683 static inline unsigned long
 684 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 685 {
 686         return 0;
 687 }
 688 static inline
 689 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 690                 enum lru_list lru, int zone_idx)
 691 {
 692         return 0;
 693 }
 694
 695 static inline unsigned long
 696 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
 697                              int nid, unsigned int lru_mask)
 698 {
 699         return 0;
 700 }
 701
 702 static inline unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
 703 {
 704         return 0;
 705 }
 706
 707 static inline void
 708 mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 709 {
 710 }
 711
 712 static inline void lock_page_memcg(struct page *page)
 713 {
 714 }
 715
 716 static inline void unlock_page_memcg(struct page *page)
 717 {
 718 }
 719
 720 static inline void mem_cgroup_handle_over_high(void)
 721 {
 722 }
 723
 724 static inline void mem_cgroup_oom_enable(void)
 725 {
 726 }
 727
 728 static inline void mem_cgroup_oom_disable(void)
 729 {
 730 }
 731
 732 static inline bool task_in_memcg_oom(struct task_struct *p)
 733 {
 734         return false;
 735 }
 736
 737 static inline bool mem_cgroup_oom_synchronize(bool wait)
 738 {
 739         return false;
 740 }
 741
 742 static inline void mem_cgroup_inc_page_stat(struct page *page,
 743                                             enum mem_cgroup_stat_index idx)
 744 {
 745 }
 746
 747 static inline void mem_cgroup_dec_page_stat(struct page *page,
 748                                             enum mem_cgroup_stat_index idx)
 749 {
 750 }
 751
 752 static inline
 753 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 754                                             gfp_t gfp_mask,
 755                                             unsigned long *total_scanned)
 756 {
 757         return 0;
 758 }
 759
 760 static inline void mem_cgroup_split_huge_fixup(struct page *head)
 761 {
 762 }
 763
 764 static inline
 765 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 766 {
 767 }
 768 #endif /* CONFIG_MEMCG */
 769
 770 #ifdef CONFIG_CGROUP_WRITEBACK
 771
 772 struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg);
 773 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
 774 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
 775                          unsigned long *pheadroom, unsigned long *pdirty,
 776                          unsigned long *pwriteback);
 777
 778 #else   /* CONFIG_CGROUP_WRITEBACK */
 779
 780 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
 781 {
 782         return NULL;
 783 }
 784
 785 static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
 786                                        unsigned long *pfilepages,
 787                                        unsigned long *pheadroom,
 788                                        unsigned long *pdirty,
 789                                        unsigned long *pwriteback)
 790 {
 791 }
 792
 793 #endif  /* CONFIG_CGROUP_WRITEBACK */
 794
 795 struct sock;
 796 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
 797 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
 798 #ifdef CONFIG_MEMCG
 799 extern struct static_key_false memcg_sockets_enabled_key;
 800 #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
 801 void mem_cgroup_sk_alloc(struct sock *sk);
 802 void mem_cgroup_sk_free(struct sock *sk);
 803 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 804 {
 805         if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)
 806                 return true;
 807         do {
 808                 if (time_before(jiffies, memcg->socket_pressure))
 809                         return true;
 810         } while ((memcg = parent_mem_cgroup(memcg)));
 811         return false;
 812 }
 813 #else
 814 #define mem_cgroup_sockets_enabled 0
 815 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
 816 static inline void mem_cgroup_sk_free(struct sock *sk) { };
 817 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
 818 {
 819         return false;
 820 }
 821 #endif
 822
 823 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
 824 void memcg_kmem_put_cache(struct kmem_cache *cachep);
 825 int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 826                             struct mem_cgroup *memcg);
 827 int memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
 828 void memcg_kmem_uncharge(struct page *page, int order);
 829
 830 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 831 extern struct static_key_false memcg_kmem_enabled_key;
 832
 833 extern int memcg_nr_cache_ids;
 834 void memcg_get_cache_ids(void);
 835 void memcg_put_cache_ids(void);
 836
 837 /*
 838  * Helper macro to loop through all memcg-specific caches. Callers must still
 839  * check if the cache is valid (it is either valid or NULL).
 840  * the slab_mutex must be held when looping through those caches
 841  */
 842 #define for_each_memcg_cache_index(_idx)        \
 843         for ((_idx) = 0; (_idx) < memcg_nr_cache_ids; (_idx)++)
 844
 845 static inline bool memcg_kmem_enabled(void)
 846 {
 847         return static_branch_unlikely(&memcg_kmem_enabled_key);
 848 }
 849
 850 /*
 851  * helper for accessing a memcg's index. It will be used as an index in the
 852  * child cache array in kmem_cache, and also to derive its name. This function
 853  * will return -1 when this is not a kmem-limited memcg.
 854  */
 855 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 856 {
 857         return memcg ? memcg->kmemcg_id : -1;
 858 }
 859
 860 /**
 861  * memcg_kmem_update_page_stat - update kmem page state statistics
 862  * @page: the page
 863  * @idx: page state item to account
 864  * @val: number of pages (positive or negative)
 865  */
 866 static inline void memcg_kmem_update_page_stat(struct page *page,
 867                                 enum mem_cgroup_stat_index idx, int val)
 868 {
 869         if (memcg_kmem_enabled() && page->mem_cgroup)
 870                 this_cpu_add(page->mem_cgroup->stat->count[idx], val);
 871 }
 872
 873 #else
 874 #define for_each_memcg_cache_index(_idx)        \
 875         for (; NULL; )
 876
 877 static inline bool memcg_kmem_enabled(void)
 878 {
 879         return false;
 880 }
 881
 882 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 883 {
 884         return -1;
 885 }
 886
 887 static inline void memcg_get_cache_ids(void)
 888 {
 889 }
 890
 891 static inline void memcg_put_cache_ids(void)
 892 {
 893 }
 894
 895 static inline void memcg_kmem_update_page_stat(struct page *page,
 896                                 enum mem_cgroup_stat_index idx, int val)
 897 {
 898 }
 899 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */
 900
 901 #endif /* _LINUX_MEMCONTROL_H */