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
  32 struct mem_cgroup;
  33 struct page;
  34 struct mm_struct;
  35 struct kmem_cache;
  36
  37 /*
  38  * The corresponding mem_cgroup_stat_names is defined in mm/memcontrol.c,
  39  * These two lists should keep in accord with each other.
  40  */
  41 enum mem_cgroup_stat_index {
  42         /*
  43          * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
  44          */
  45         MEM_CGROUP_STAT_CACHE,          /* # of pages charged as cache */
  46         MEM_CGROUP_STAT_RSS,            /* # of pages charged as anon rss */
  47         MEM_CGROUP_STAT_RSS_HUGE,       /* # of pages charged as anon huge */
  48         MEM_CGROUP_STAT_FILE_MAPPED,    /* # of pages charged as file rss */
  49         MEM_CGROUP_STAT_DIRTY,          /* # of dirty pages in page cache */
  50         MEM_CGROUP_STAT_WRITEBACK,      /* # of pages under writeback */
  51         MEM_CGROUP_STAT_SWAP,           /* # of pages, swapped out */
  52         MEM_CGROUP_STAT_NSTATS,
  53 };
  54
  55 struct mem_cgroup_reclaim_cookie {
  56         struct zone *zone;
  57         int priority;
  58         unsigned int generation;
  59 };
  60
  61 enum mem_cgroup_events_index {
  62         MEM_CGROUP_EVENTS_PGPGIN,       /* # of pages paged in */
  63         MEM_CGROUP_EVENTS_PGPGOUT,      /* # of pages paged out */
  64         MEM_CGROUP_EVENTS_PGFAULT,      /* # of page-faults */
  65         MEM_CGROUP_EVENTS_PGMAJFAULT,   /* # of major page-faults */
  66         MEM_CGROUP_EVENTS_NSTATS,
  67         /* default hierarchy events */
  68         MEMCG_LOW = MEM_CGROUP_EVENTS_NSTATS,
  69         MEMCG_HIGH,
  70         MEMCG_MAX,
  71         MEMCG_OOM,
  72         MEMCG_NR_EVENTS,
  73 };
  74
  75 /*
  76  * Per memcg event counter is incremented at every pagein/pageout. With THP,
  77  * it will be incremated by the number of pages. This counter is used for
  78  * for trigger some periodic events. This is straightforward and better
  79  * than using jiffies etc. to handle periodic memcg event.
  80  */
  81 enum mem_cgroup_events_target {
  82         MEM_CGROUP_TARGET_THRESH,
  83         MEM_CGROUP_TARGET_SOFTLIMIT,
  84         MEM_CGROUP_TARGET_NUMAINFO,
  85         MEM_CGROUP_NTARGETS,
  86 };
  87
  88 struct cg_proto {
  89         struct page_counter     memory_allocated;       /* Current allocated memory. */
  90         int                     memory_pressure;
  91         bool                    active;
  92         /*
  93          * memcg field is used to find which memcg we belong directly
  94          * Each memcg struct can hold more than one cg_proto, so container_of
  95          * won't really cut.
  96          *
  97          * The elegant solution would be having an inverse function to
  98          * proto_cgroup in struct proto, but that means polluting the structure
  99          * for everybody, instead of just for memcg users.
 100          */
 101         struct mem_cgroup       *memcg;
 102 };
 103
 104 #ifdef CONFIG_MEMCG
 105 struct mem_cgroup_stat_cpu {
 106         long count[MEM_CGROUP_STAT_NSTATS];
 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_zone {
 122         struct lruvec           lruvec;
 123         unsigned long           lru_size[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_per_node {
 136         struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
 137 };
 138
 139 struct mem_cgroup_threshold {
 140         struct eventfd_ctx *eventfd;
 141         unsigned long threshold;
 142 };
 143
 144 /* For threshold */
 145 struct mem_cgroup_threshold_ary {
 146         /* An array index points to threshold just below or equal to usage. */
 147         int current_threshold;
 148         /* Size of entries[] */
 149         unsigned int size;
 150         /* Array of thresholds */
 151         struct mem_cgroup_threshold entries[0];
 152 };
 153
 154 struct mem_cgroup_thresholds {
 155         /* Primary thresholds array */
 156         struct mem_cgroup_threshold_ary *primary;
 157         /*
 158          * Spare threshold array.
 159          * This is needed to make mem_cgroup_unregister_event() "never fail".
 160          * It must be able to store at least primary->size - 1 entries.
 161          */
 162         struct mem_cgroup_threshold_ary *spare;
 163 };
 164
 165 /*
 166  * The memory controller data structure. The memory controller controls both
 167  * page cache and RSS per cgroup. We would eventually like to provide
 168  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 169  * to help the administrator determine what knobs to tune.
 170  */
 171 struct mem_cgroup {
 172         struct cgroup_subsys_state css;
 173
 174         /* Accounted resources */
 175         struct page_counter memory;
 176         struct page_counter memsw;
 177         struct page_counter kmem;
 178
 179         /* Normal memory consumption range */
 180         unsigned long low;
 181         unsigned long high;
 182
 183         unsigned long soft_limit;
 184
 185         /* vmpressure notifications */
 186         struct vmpressure vmpressure;
 187
 188         /* css_online() has been completed */
 189         int initialized;
 190
 191         /*
 192          * Should the accounting and control be hierarchical, per subtree?
 193          */
 194         bool use_hierarchy;
 195
 196         /* protected by memcg_oom_lock */
 197         bool            oom_lock;
 198         int             under_oom;
 199
 200         int     swappiness;
 201         /* OOM-Killer disable */
 202         int             oom_kill_disable;
 203
 204         /* handle for "memory.events" */
 205         struct cgroup_file events_file;
 206
 207         /* protect arrays of thresholds */
 208         struct mutex thresholds_lock;
 209
 210         /* thresholds for memory usage. RCU-protected */
 211         struct mem_cgroup_thresholds thresholds;
 212
 213         /* thresholds for mem+swap usage. RCU-protected */
 214         struct mem_cgroup_thresholds memsw_thresholds;
 215
 216         /* For oom notifier event fd */
 217         struct list_head oom_notify;
 218
 219         /*
 220          * Should we move charges of a task when a task is moved into this
 221          * mem_cgroup ? And what type of charges should we move ?
 222          */
 223         unsigned long move_charge_at_immigrate;
 224         /*
 225          * set > 0 if pages under this cgroup are moving to other cgroup.
 226          */
 227         atomic_t                moving_account;
 228         /* taken only while moving_account > 0 */
 229         spinlock_t              move_lock;
 230         struct task_struct      *move_lock_task;
 231         unsigned long           move_lock_flags;
 232         /*
 233          * percpu counter.
 234          */
 235         struct mem_cgroup_stat_cpu __percpu *stat;
 236
 237 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
 238         struct cg_proto tcp_mem;
 239 #endif
 240 #if defined(CONFIG_MEMCG_KMEM)
 241         /* Index in the kmem_cache->memcg_params.memcg_caches array */
 242         int kmemcg_id;
 243         bool kmem_acct_activated;
 244         bool kmem_acct_active;
 245 #endif
 246
 247         int last_scanned_node;
 248 #if MAX_NUMNODES > 1
 249         nodemask_t      scan_nodes;
 250         atomic_t        numainfo_events;
 251         atomic_t        numainfo_updating;
 252 #endif
 253
 254 #ifdef CONFIG_CGROUP_WRITEBACK
 255         struct list_head cgwb_list;
 256         struct wb_domain cgwb_domain;
 257 #endif
 258
 259         /* List of events which userspace want to receive */
 260         struct list_head event_list;
 261         spinlock_t event_list_lock;
 262
 263         struct mem_cgroup_per_node *nodeinfo[0];
 264         /* WARNING: nodeinfo must be the last member here */
 265 };
 266
 267 extern struct mem_cgroup *root_mem_cgroup;
 268
 269 /**
 270  * mem_cgroup_events - count memory events against a cgroup
 271  * @memcg: the memory cgroup
 272  * @idx: the event index
 273  * @nr: the number of events to account for
 274  */
 275 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 276                        enum mem_cgroup_events_index idx,
 277                        unsigned int nr)
 278 {
 279         this_cpu_add(memcg->stat->events[idx], nr);
 280         cgroup_file_notify(&memcg->events_file);
 281 }
 282
 283 bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg);
 284
 285 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 286                           gfp_t gfp_mask, struct mem_cgroup **memcgp);
 287 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
 288                               bool lrucare);
 289 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg);
 290 void mem_cgroup_uncharge(struct page *page);
 291 void mem_cgroup_uncharge_list(struct list_head *page_list);
 292
 293 void mem_cgroup_replace_page(struct page *oldpage, struct page *newpage);
 294
 295 struct lruvec *mem_cgroup_zone_lruvec(struct zone *, struct mem_cgroup *);
 296 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct zone *);
 297
 298 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg);
 299 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 300 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg);
 301
 302 static inline
 303 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 304         return css ? container_of(css, struct mem_cgroup, css) : NULL;
 305 }
 306
 307 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
 308                                    struct mem_cgroup *,
 309                                    struct mem_cgroup_reclaim_cookie *);
 310 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
 311
 312 static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
 313                               struct mem_cgroup *root)
 314 {
 315         if (root == memcg)
 316                 return true;
 317         if (!root->use_hierarchy)
 318                 return false;
 319         return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
 320 }
 321
 322 static inline bool mm_match_cgroup(struct mm_struct *mm,
 323                                    struct mem_cgroup *memcg)
 324 {
 325         struct mem_cgroup *task_memcg;
 326         bool match = false;
 327
 328         rcu_read_lock();
 329         task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 330         if (task_memcg)
 331                 match = mem_cgroup_is_descendant(task_memcg, memcg);
 332         rcu_read_unlock();
 333         return match;
 334 }
 335
 336 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
 337 ino_t page_cgroup_ino(struct page *page);
 338
 339 static inline bool mem_cgroup_disabled(void)
 340 {
 341         return !cgroup_subsys_enabled(memory_cgrp_subsys);
 342 }
 343
 344 /*
 345  * For memory reclaim.
 346  */
 347 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
 348
 349 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 350                 int nr_pages);
 351
 352 static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec)
 353 {
 354         struct mem_cgroup_per_zone *mz;
 355         struct mem_cgroup *memcg;
 356
 357         if (mem_cgroup_disabled())
 358                 return true;
 359
 360         mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
 361         memcg = mz->memcg;
 362
 363         return !!(memcg->css.flags & CSS_ONLINE);
 364 }
 365
 366 static inline
 367 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 368 {
 369         struct mem_cgroup_per_zone *mz;
 370
 371         mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
 372         return mz->lru_size[lru];
 373 }
 374
 375 static inline bool mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
 376 {
 377         unsigned long inactive_ratio;
 378         unsigned long inactive;
 379         unsigned long active;
 380         unsigned long gb;
 381
 382         inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
 383         active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
 384
 385         gb = (inactive + active) >> (30 - PAGE_SHIFT);
 386         if (gb)
 387                 inactive_ratio = int_sqrt(10 * gb);
 388         else
 389                 inactive_ratio = 1;
 390
 391         return inactive * inactive_ratio < active;
 392 }
 393
 394 void mem_cgroup_handle_over_high(void);
 395
 396 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg,
 397                                 struct task_struct *p);
 398
 399 static inline void mem_cgroup_oom_enable(void)
 400 {
 401         WARN_ON(current->memcg_may_oom);
 402         current->memcg_may_oom = 1;
 403 }
 404
 405 static inline void mem_cgroup_oom_disable(void)
 406 {
 407         WARN_ON(!current->memcg_may_oom);
 408         current->memcg_may_oom = 0;
 409 }
 410
 411 static inline bool task_in_memcg_oom(struct task_struct *p)
 412 {
 413         return p->memcg_in_oom;
 414 }
 415
 416 bool mem_cgroup_oom_synchronize(bool wait);
 417
 418 #ifdef CONFIG_MEMCG_SWAP
 419 extern int do_swap_account;
 420 #endif
 421
 422 struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page);
 423 void mem_cgroup_end_page_stat(struct mem_cgroup *memcg);
 424
 425 /**
 426  * mem_cgroup_update_page_stat - update page state statistics
 427  * @memcg: memcg to account against
 428  * @idx: page state item to account
 429  * @val: number of pages (positive or negative)
 430  *
 431  * See mem_cgroup_begin_page_stat() for locking requirements.
 432  */
 433 static inline void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
 434                                  enum mem_cgroup_stat_index idx, int val)
 435 {
 436         VM_BUG_ON(!rcu_read_lock_held());
 437
 438         if (memcg)
 439                 this_cpu_add(memcg->stat->count[idx], val);
 440 }
 441
 442 static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
 443                                             enum mem_cgroup_stat_index idx)
 444 {
 445         mem_cgroup_update_page_stat(memcg, idx, 1);
 446 }
 447
 448 static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
 449                                             enum mem_cgroup_stat_index idx)
 450 {
 451         mem_cgroup_update_page_stat(memcg, idx, -1);
 452 }
 453
 454 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 455                                                 gfp_t gfp_mask,
 456                                                 unsigned long *total_scanned);
 457
 458 static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,
 459                                              enum vm_event_item idx)
 460 {
 461         struct mem_cgroup *memcg;
 462
 463         if (mem_cgroup_disabled())
 464                 return;
 465
 466         rcu_read_lock();
 467         memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 468         if (unlikely(!memcg))
 469                 goto out;
 470
 471         switch (idx) {
 472         case PGFAULT:
 473                 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
 474                 break;
 475         case PGMAJFAULT:
 476                 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
 477                 break;
 478         default:
 479                 BUG();
 480         }
 481 out:
 482         rcu_read_unlock();
 483 }
 484 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 485 void mem_cgroup_split_huge_fixup(struct page *head);
 486 #endif
 487
 488 #else /* CONFIG_MEMCG */
 489 struct mem_cgroup;
 490
 491 static inline void mem_cgroup_events(struct mem_cgroup *memcg,
 492                                      enum mem_cgroup_events_index idx,
 493                                      unsigned int nr)
 494 {
 495 }
 496
 497 static inline bool mem_cgroup_low(struct mem_cgroup *root,
 498                                   struct mem_cgroup *memcg)
 499 {
 500         return false;
 501 }
 502
 503 static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 504                                         gfp_t gfp_mask,
 505                                         struct mem_cgroup **memcgp)
 506 {
 507         *memcgp = NULL;
 508         return 0;
 509 }
 510
 511 static inline void mem_cgroup_commit_charge(struct page *page,
 512                                             struct mem_cgroup *memcg,
 513                                             bool lrucare)
 514 {
 515 }
 516
 517 static inline void mem_cgroup_cancel_charge(struct page *page,
 518                                             struct mem_cgroup *memcg)
 519 {
 520 }
 521
 522 static inline void mem_cgroup_uncharge(struct page *page)
 523 {
 524 }
 525
 526 static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
 527 {
 528 }
 529
 530 static inline void mem_cgroup_replace_page(struct page *old, struct page *new)
 531 {
 532 }
 533
 534 static inline struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
 535                                                     struct mem_cgroup *memcg)
 536 {
 537         return &zone->lruvec;
 538 }
 539
 540 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 541                                                     struct zone *zone)
 542 {
 543         return &zone->lruvec;
 544 }
 545
 546 static inline bool mm_match_cgroup(struct mm_struct *mm,
 547                 struct mem_cgroup *memcg)
 548 {
 549         return true;
 550 }
 551
 552 static inline bool task_in_mem_cgroup(struct task_struct *task,
 553                                       const struct mem_cgroup *memcg)
 554 {
 555         return true;
 556 }
 557
 558 static inline struct mem_cgroup *
 559 mem_cgroup_iter(struct mem_cgroup *root,
 560                 struct mem_cgroup *prev,
 561                 struct mem_cgroup_reclaim_cookie *reclaim)
 562 {
 563         return NULL;
 564 }
 565
 566 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 567                                          struct mem_cgroup *prev)
 568 {
 569 }
 570
 571 static inline bool mem_cgroup_disabled(void)
 572 {
 573         return true;
 574 }
 575
 576 static inline bool
 577 mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
 578 {
 579         return true;
 580 }
 581
 582 static inline bool mem_cgroup_lruvec_online(struct lruvec *lruvec)
 583 {
 584         return true;
 585 }
 586
 587 static inline unsigned long
 588 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
 589 {
 590         return 0;
 591 }
 592
 593 static inline void
 594 mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 595                               int increment)
 596 {
 597 }
 598
 599 static inline void
 600 mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 601 {
 602 }
 603
 604 static inline struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page)
 605 {
 606         return NULL;
 607 }
 608
 609 static inline void mem_cgroup_end_page_stat(struct mem_cgroup *memcg)
 610 {
 611 }
 612
 613 static inline void mem_cgroup_handle_over_high(void)
 614 {
 615 }
 616
 617 static inline void mem_cgroup_oom_enable(void)
 618 {
 619 }
 620
 621 static inline void mem_cgroup_oom_disable(void)
 622 {
 623 }
 624
 625 static inline bool task_in_memcg_oom(struct task_struct *p)
 626 {
 627         return false;
 628 }
 629
 630 static inline bool mem_cgroup_oom_synchronize(bool wait)
 631 {
 632         return false;
 633 }
 634
 635 static inline void mem_cgroup_inc_page_stat(struct mem_cgroup *memcg,
 636                                             enum mem_cgroup_stat_index idx)
 637 {
 638 }
 639
 640 static inline void mem_cgroup_dec_page_stat(struct mem_cgroup *memcg,
 641                                             enum mem_cgroup_stat_index idx)
 642 {
 643 }
 644
 645 static inline
 646 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 647                                             gfp_t gfp_mask,
 648                                             unsigned long *total_scanned)
 649 {
 650         return 0;
 651 }
 652
 653 static inline void mem_cgroup_split_huge_fixup(struct page *head)
 654 {
 655 }
 656
 657 static inline
 658 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
 659 {
 660 }
 661 #endif /* CONFIG_MEMCG */
 662
 663 #ifdef CONFIG_CGROUP_WRITEBACK
 664
 665 struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg);
 666 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
 667 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
 668                          unsigned long *pheadroom, unsigned long *pdirty,
 669                          unsigned long *pwriteback);
 670
 671 #else   /* CONFIG_CGROUP_WRITEBACK */
 672
 673 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
 674 {
 675         return NULL;
 676 }
 677
 678 static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
 679                                        unsigned long *pfilepages,
 680                                        unsigned long *pheadroom,
 681                                        unsigned long *pdirty,
 682                                        unsigned long *pwriteback)
 683 {
 684 }
 685
 686 #endif  /* CONFIG_CGROUP_WRITEBACK */
 687
 688 struct sock;
 689 void sock_update_memcg(struct sock *sk);
 690 void sock_release_memcg(struct sock *sk);
 691 bool mem_cgroup_charge_skmem(struct cg_proto *proto, unsigned int nr_pages);
 692 void mem_cgroup_uncharge_skmem(struct cg_proto *proto, unsigned int nr_pages);
 693 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
 694 static inline bool mem_cgroup_under_socket_pressure(struct cg_proto *proto)
 695 {
 696         return proto->memory_pressure;
 697 }
 698 #else
 699 static inline bool mem_cgroup_under_pressure(struct cg_proto *proto)
 700 {
 701         return false;
 702 }
 703 #endif
 704
 705 #ifdef CONFIG_MEMCG_KMEM
 706 extern struct static_key memcg_kmem_enabled_key;
 707
 708 extern int memcg_nr_cache_ids;
 709 void memcg_get_cache_ids(void);
 710 void memcg_put_cache_ids(void);
 711
 712 /*
 713  * Helper macro to loop through all memcg-specific caches. Callers must still
 714  * check if the cache is valid (it is either valid or NULL).
 715  * the slab_mutex must be held when looping through those caches
 716  */
 717 #define for_each_memcg_cache_index(_idx)        \
 718         for ((_idx) = 0; (_idx) < memcg_nr_cache_ids; (_idx)++)
 719
 720 static inline bool memcg_kmem_enabled(void)
 721 {
 722         return static_key_false(&memcg_kmem_enabled_key);
 723 }
 724
 725 static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
 726 {
 727         return memcg->kmem_acct_active;
 728 }
 729
 730 /*
 731  * In general, we'll do everything in our power to not incur in any overhead
 732  * for non-memcg users for the kmem functions. Not even a function call, if we
 733  * can avoid it.
 734  *
 735  * Therefore, we'll inline all those functions so that in the best case, we'll
 736  * see that kmemcg is off for everybody and proceed quickly.  If it is on,
 737  * we'll still do most of the flag checking inline. We check a lot of
 738  * conditions, but because they are pretty simple, they are expected to be
 739  * fast.
 740  */
 741 int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
 742                               struct mem_cgroup *memcg);
 743 int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
 744 void __memcg_kmem_uncharge(struct page *page, int order);
 745
 746 /*
 747  * helper for acessing a memcg's index. It will be used as an index in the
 748  * child cache array in kmem_cache, and also to derive its name. This function
 749  * will return -1 when this is not a kmem-limited memcg.
 750  */
 751 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 752 {
 753         return memcg ? memcg->kmemcg_id : -1;
 754 }
 755
 756 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
 757 void __memcg_kmem_put_cache(struct kmem_cache *cachep);
 758
 759 static inline bool __memcg_kmem_bypass(void)
 760 {
 761         if (!memcg_kmem_enabled())
 762                 return true;
 763         if (in_interrupt() || (!current->mm) || (current->flags & PF_KTHREAD))
 764                 return true;
 765         return false;
 766 }
 767
 768 /**
 769  * memcg_kmem_charge: charge a kmem page
 770  * @page: page to charge
 771  * @gfp: reclaim mode
 772  * @order: allocation order
 773  *
 774  * Returns 0 on success, an error code on failure.
 775  */
 776 static __always_inline int memcg_kmem_charge(struct page *page,
 777                                              gfp_t gfp, int order)
 778 {
 779         if (__memcg_kmem_bypass())
 780                 return 0;
 781         if (!(gfp & __GFP_ACCOUNT))
 782                 return 0;
 783         return __memcg_kmem_charge(page, gfp, order);
 784 }
 785
 786 /**
 787  * memcg_kmem_uncharge: uncharge a kmem page
 788  * @page: page to uncharge
 789  * @order: allocation order
 790  */
 791 static __always_inline void memcg_kmem_uncharge(struct page *page, int order)
 792 {
 793         if (memcg_kmem_enabled())
 794                 __memcg_kmem_uncharge(page, order);
 795 }
 796
 797 /**
 798  * memcg_kmem_get_cache: selects the correct per-memcg cache for allocation
 799  * @cachep: the original global kmem cache
 800  *
 801  * All memory allocated from a per-memcg cache is charged to the owner memcg.
 802  */
 803 static __always_inline struct kmem_cache *
 804 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 805 {
 806         if (__memcg_kmem_bypass())
 807                 return cachep;
 808         return __memcg_kmem_get_cache(cachep, gfp);
 809 }
 810
 811 static __always_inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
 812 {
 813         if (memcg_kmem_enabled())
 814                 __memcg_kmem_put_cache(cachep);
 815 }
 816 #else
 817 #define for_each_memcg_cache_index(_idx)        \
 818         for (; NULL; )
 819
 820 static inline bool memcg_kmem_enabled(void)
 821 {
 822         return false;
 823 }
 824
 825 static inline bool memcg_kmem_is_active(struct mem_cgroup *memcg)
 826 {
 827         return false;
 828 }
 829
 830 static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
 831 {
 832         return 0;
 833 }
 834
 835 static inline void memcg_kmem_uncharge(struct page *page, int order)
 836 {
 837 }
 838
 839 static inline int memcg_cache_id(struct mem_cgroup *memcg)
 840 {
 841         return -1;
 842 }
 843
 844 static inline void memcg_get_cache_ids(void)
 845 {
 846 }
 847
 848 static inline void memcg_put_cache_ids(void)
 849 {
 850 }
 851
 852 static inline struct kmem_cache *
 853 memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 854 {
 855         return cachep;
 856 }
 857
 858 static inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
 859 {
 860 }
 861 #endif /* CONFIG_MEMCG_KMEM */
 862 #endif /* _LINUX_MEMCONTROL_H */