include/linux/memcontrol.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* memcontrol.h - Memory Controller
   3  *
   4  * Copyright IBM Corporation, 2007
   5  * Author Balbir Singh <balbir@linux.vnet.ibm.com>
   6  *
   7  * Copyright 2007 OpenVZ SWsoft Inc
   8  * Author: Pavel Emelianov <xemul@openvz.org>
   9  */
  10
  11 #ifndef _LINUX_MEMCONTROL_H
  12 #define _LINUX_MEMCONTROL_H
  13 #include <linux/cgroup.h>
  14 #include <linux/vm_event_item.h>
  15 #include <linux/hardirq.h>
  16 #include <linux/jump_label.h>
  17 #include <linux/page_counter.h>
  18 #include <linux/vmpressure.h>
  19 #include <linux/eventfd.h>
  20 #include <linux/mm.h>
  21 #include <linux/vmstat.h>
  22 #include <linux/writeback.h>
  23 #include <linux/page-flags.h>
  24
  25 struct mem_cgroup;
  26 struct page;
  27 struct mm_struct;
  28 struct kmem_cache;
  29
  30 /* Cgroup-specific page state, on top of universal node page state */
  31 enum memcg_stat_item {
  32         MEMCG_CACHE = NR_VM_NODE_STAT_ITEMS,
  33         MEMCG_RSS,
  34         MEMCG_RSS_HUGE,
  35         MEMCG_SWAP,
  36         MEMCG_SOCK,
  37         /* XXX: why are these zone and not node counters? */
  38         MEMCG_KERNEL_STACK_KB,
  39         MEMCG_NR_STAT,
  40 };
  41
  42 enum memcg_memory_event {
  43         MEMCG_LOW,
  44         MEMCG_HIGH,
  45         MEMCG_MAX,
  46         MEMCG_OOM,
  47         MEMCG_OOM_KILL,
  48         MEMCG_SWAP_MAX,
  49         MEMCG_SWAP_FAIL,
  50         MEMCG_NR_MEMORY_EVENTS,
  51 };
  52
  53 enum mem_cgroup_protection {
  54         MEMCG_PROT_NONE,
  55         MEMCG_PROT_LOW,
  56         MEMCG_PROT_MIN,
  57 };
  58
  59 struct mem_cgroup_reclaim_cookie {
  60         pg_data_t *pgdat;
  61         unsigned int generation;
  62 };
  63
  64 #ifdef CONFIG_MEMCG
  65
  66 #define MEM_CGROUP_ID_SHIFT     16
  67 #define MEM_CGROUP_ID_MAX       USHRT_MAX
  68
  69 struct mem_cgroup_id {
  70         int id;
  71         refcount_t ref;
  72 };
  73
  74 /*
  75  * Per memcg event counter is incremented at every pagein/pageout. With THP,
  76  * it will be incremated by the number of pages. This counter is used for
  77  * for trigger some periodic events. This is straightforward and better
  78  * than using jiffies etc. to handle periodic memcg event.
  79  */
  80 enum mem_cgroup_events_target {
  81         MEM_CGROUP_TARGET_THRESH,
  82         MEM_CGROUP_TARGET_SOFTLIMIT,
  83         MEM_CGROUP_NTARGETS,
  84 };
  85
  86 struct memcg_vmstats_percpu {
  87         long stat[MEMCG_NR_STAT];
  88         unsigned long events[NR_VM_EVENT_ITEMS];
  89         unsigned long nr_page_events;
  90         unsigned long targets[MEM_CGROUP_NTARGETS];
  91 };
  92
  93 struct mem_cgroup_reclaim_iter {
  94         struct mem_cgroup *position;
  95         /* scan generation, increased every round-trip */
  96         unsigned int generation;
  97 };
  98
  99 struct lruvec_stat {
 100         long count[NR_VM_NODE_STAT_ITEMS];
 101 };
 102
 103 /*
 104  * Bitmap of shrinker::id corresponding to memcg-aware shrinkers,
 105  * which have elements charged to this memcg.
 106  */
 107 struct memcg_shrinker_map {
 108         struct rcu_head rcu;
 109         unsigned long map[];
 110 };
 111
 112 /*
 113  * per-node information in memory controller.
 114  */
 115 struct mem_cgroup_per_node {
 116         struct lruvec           lruvec;
 117
 118         /* Legacy local VM stats */
 119         struct lruvec_stat __percpu *lruvec_stat_local;
 120
 121         /* Subtree VM stats (batched updates) */
 122         struct lruvec_stat __percpu *lruvec_stat_cpu;
 123         atomic_long_t           lruvec_stat[NR_VM_NODE_STAT_ITEMS];
 124
 125         unsigned long           lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];
 126
 127         struct mem_cgroup_reclaim_iter  iter;
 128
 129         struct memcg_shrinker_map __rcu *shrinker_map;
 130
 131         struct rb_node          tree_node;      /* RB tree node */
 132         unsigned long           usage_in_excess;/* Set to the value by which */
 133                                                 /* the soft limit is exceeded*/
 134         bool                    on_tree;
 135         struct mem_cgroup       *memcg;         /* Back pointer, we cannot */
 136                                                 /* use container_of        */
 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[];
 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 enum memcg_kmem_state {
 166         KMEM_NONE,
 167         KMEM_ALLOCATED,
 168         KMEM_ONLINE,
 169 };
 170
 171 #if defined(CONFIG_SMP)
 172 struct memcg_padding {
 173         char x[0];
 174 } ____cacheline_internodealigned_in_smp;
 175 #define MEMCG_PADDING(name)      struct memcg_padding name;
 176 #else
 177 #define MEMCG_PADDING(name)
 178 #endif
 179
 180 /*
 181  * Remember four most recent foreign writebacks with dirty pages in this
 182  * cgroup.  Inode sharing is expected to be uncommon and, even if we miss
 183  * one in a given round, we're likely to catch it later if it keeps
 184  * foreign-dirtying, so a fairly low count should be enough.
 185  *
 186  * See mem_cgroup_track_foreign_dirty_slowpath() for details.
 187  */
 188 #define MEMCG_CGWB_FRN_CNT      4
 189
 190 struct memcg_cgwb_frn {
 191         u64 bdi_id;                     /* bdi->id of the foreign inode */
 192         int memcg_id;                   /* memcg->css.id of foreign inode */
 193         u64 at;                         /* jiffies_64 at the time of dirtying */
 194         struct wb_completion done;      /* tracks in-flight foreign writebacks */
 195 };
 196
 197 /*
 198  * The memory controller data structure. The memory controller controls both
 199  * page cache and RSS per cgroup. We would eventually like to provide
 200  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
 201  * to help the administrator determine what knobs to tune.
 202  */
 203 struct mem_cgroup {
 204         struct cgroup_subsys_state css;
 205
 206         /* Private memcg ID. Used to ID objects that outlive the cgroup */
 207         struct mem_cgroup_id id;
 208
 209         /* Accounted resources */
 210         struct page_counter memory;
 211         struct page_counter swap;
 212
 213         /* Legacy consumer-oriented counters */
 214         struct page_counter memsw;
 215         struct page_counter kmem;
 216         struct page_counter tcpmem;
 217
 218         /* Upper bound of normal memory consumption range */
 219         unsigned long high;
 220
 221         /* Range enforcement for interrupt charges */
 222         struct work_struct high_work;
 223
 224         unsigned long soft_limit;
 225
 226         /* vmpressure notifications */
 227         struct vmpressure vmpressure;
 228
 229         /*
 230          * Should the accounting and control be hierarchical, per subtree?
 231          */
 232         bool use_hierarchy;
 233
 234         /*
 235          * Should the OOM killer kill all belonging tasks, had it kill one?
 236          */
 237         bool oom_group;
 238
 239         /* protected by memcg_oom_lock */
 240         bool            oom_lock;
 241         int             under_oom;
 242
 243         int     swappiness;
 244         /* OOM-Killer disable */
 245         int             oom_kill_disable;
 246
 247         /* memory.events and memory.events.local */
 248         struct cgroup_file events_file;
 249         struct cgroup_file events_local_file;
 250
 251         /* handle for "memory.swap.events" */
 252         struct cgroup_file swap_events_file;
 253
 254         /* protect arrays of thresholds */
 255         struct mutex thresholds_lock;
 256
 257         /* thresholds for memory usage. RCU-protected */
 258         struct mem_cgroup_thresholds thresholds;
 259
 260         /* thresholds for mem+swap usage. RCU-protected */
 261         struct mem_cgroup_thresholds memsw_thresholds;
 262
 263         /* For oom notifier event fd */
 264         struct list_head oom_notify;
 265
 266         /*
 267          * Should we move charges of a task when a task is moved into this
 268          * mem_cgroup ? And what type of charges should we move ?
 269          */
 270         unsigned long move_charge_at_immigrate;
 271         /* taken only while moving_account > 0 */
 272         spinlock_t              move_lock;
 273         unsigned long           move_lock_flags;
 274
 275         MEMCG_PADDING(_pad1_);
 276
 277         /*
 278          * set > 0 if pages under this cgroup are moving to other cgroup.
 279          */
 280         atomic_t                moving_account;
 281         struct task_struct      *move_lock_task;
 282
 283         /* Legacy local VM stats and events */
 284         struct memcg_vmstats_percpu __percpu *vmstats_local;
 285
 286         /* Subtree VM stats and events (batched updates) */
 287         struct memcg_vmstats_percpu __percpu *vmstats_percpu;
 288
 289         MEMCG_PADDING(_pad2_);
 290
 291         atomic_long_t           vmstats[MEMCG_NR_STAT];
 292         atomic_long_t           vmevents[NR_VM_EVENT_ITEMS];
 293
 294         /* memory.events */
 295         atomic_long_t           memory_events[MEMCG_NR_MEMORY_EVENTS];
 296         atomic_long_t           memory_events_local[MEMCG_NR_MEMORY_EVENTS];
 297
 298         unsigned long           socket_pressure;
 299
 300         /* Legacy tcp memory accounting */
 301         bool                    tcpmem_active;
 302         int                     tcpmem_pressure;
 303
 304 #ifdef CONFIG_MEMCG_KMEM
 305         /* Index in the kmem_cache->memcg_params.memcg_caches array */
 306         int kmemcg_id;
 307         enum memcg_kmem_state kmem_state;
 308         struct list_head kmem_caches;
 309 #endif
 310
 311 #ifdef CONFIG_CGROUP_WRITEBACK
 312         struct list_head cgwb_list;
 313         struct wb_domain cgwb_domain;
 314         struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT];
 315 #endif
 316
 317         /* List of events which userspace want to receive */
 318         struct list_head event_list;
 319         spinlock_t event_list_lock;
 320
 321 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 322         struct deferred_split deferred_split_queue;
 323 #endif
 324
 325         struct mem_cgroup_per_node *nodeinfo[0];
 326         /* WARNING: nodeinfo must be the last member here */
 327 };
 328
 329 /*
 330  * size of first charge trial. "32" comes from vmscan.c's magic value.
 331  * TODO: maybe necessary to use big numbers in big irons.
 332  */
 333 #define MEMCG_CHARGE_BATCH 32U
 334
 335 extern struct mem_cgroup *root_mem_cgroup;
 336
 337 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 338 {
 339         return (memcg == root_mem_cgroup);
 340 }
 341
 342 static inline bool mem_cgroup_disabled(void)
 343 {
 344         return !cgroup_subsys_enabled(memory_cgrp_subsys);
 345 }
 346
 347 static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
 348                                                   bool in_low_reclaim)
 349 {
 350         if (mem_cgroup_disabled())
 351                 return 0;
 352
 353         if (in_low_reclaim)
 354                 return READ_ONCE(memcg->memory.emin);
 355
 356         return max(READ_ONCE(memcg->memory.emin),
 357                    READ_ONCE(memcg->memory.elow));
 358 }
 359
 360 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
 361                                                 struct mem_cgroup *memcg);
 362
 363 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 364                           gfp_t gfp_mask, struct mem_cgroup **memcgp,
 365                           bool compound);
 366 int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm,
 367                           gfp_t gfp_mask, struct mem_cgroup **memcgp,
 368                           bool compound);
 369 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
 370                               bool lrucare, bool compound);
 371 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
 372                 bool compound);
 373 void mem_cgroup_uncharge(struct page *page);
 374 void mem_cgroup_uncharge_list(struct list_head *page_list);
 375
 376 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
 377
 378 static struct mem_cgroup_per_node *
 379 mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
 380 {
 381         return memcg->nodeinfo[nid];
 382 }
 383
 384 /**
 385  * mem_cgroup_lruvec - get the lru list vector for a memcg & node
 386  * @memcg: memcg of the wanted lruvec
 387  *
 388  * Returns the lru list vector holding pages for a given @memcg &
 389  * @node combination. This can be the node lruvec, if the memory
 390  * controller is disabled.
 391  */
 392 static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
 393                                                struct pglist_data *pgdat)
 394 {
 395         struct mem_cgroup_per_node *mz;
 396         struct lruvec *lruvec;
 397
 398         if (mem_cgroup_disabled()) {
 399                 lruvec = &pgdat->__lruvec;
 400                 goto out;
 401         }
 402
 403         if (!memcg)
 404                 memcg = root_mem_cgroup;
 405
 406         mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
 407         lruvec = &mz->lruvec;
 408 out:
 409         /*
 410          * Since a node can be onlined after the mem_cgroup was created,
 411          * we have to be prepared to initialize lruvec->pgdat here;
 412          * and if offlined then reonlined, we need to reinitialize it.
 413          */
 414         if (unlikely(lruvec->pgdat != pgdat))
 415                 lruvec->pgdat = pgdat;
 416         return lruvec;
 417 }
 418
 419 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
 420
 421 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
 422
 423 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
 424
 425 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page);
 426
 427 static inline
 428 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
 429         return css ? container_of(css, struct mem_cgroup, css) : NULL;
 430 }
 431
 432 static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 433 {
 434         if (memcg)
 435                 css_put(&memcg->css);
 436 }
 437
 438 #define mem_cgroup_from_counter(counter, member)        \
 439         container_of(counter, struct mem_cgroup, member)
 440
 441 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
 442                                    struct mem_cgroup *,
 443                                    struct mem_cgroup_reclaim_cookie *);
 444 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
 445 int mem_cgroup_scan_tasks(struct mem_cgroup *,
 446                           int (*)(struct task_struct *, void *), void *);
 447
 448 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 449 {
 450         if (mem_cgroup_disabled())
 451                 return 0;
 452
 453         return memcg->id.id;
 454 }
 455 struct mem_cgroup *mem_cgroup_from_id(unsigned short id);
 456
 457 static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
 458 {
 459         return mem_cgroup_from_css(seq_css(m));
 460 }
 461
 462 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
 463 {
 464         struct mem_cgroup_per_node *mz;
 465
 466         if (mem_cgroup_disabled())
 467                 return NULL;
 468
 469         mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 470         return mz->memcg;
 471 }
 472
 473 /**
 474  * parent_mem_cgroup - find the accounting parent of a memcg
 475  * @memcg: memcg whose parent to find
 476  *
 477  * Returns the parent memcg, or NULL if this is the root or the memory
 478  * controller is in legacy no-hierarchy mode.
 479  */
 480 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 481 {
 482         if (!memcg->memory.parent)
 483                 return NULL;
 484         return mem_cgroup_from_counter(memcg->memory.parent, memory);
 485 }
 486
 487 static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
 488                               struct mem_cgroup *root)
 489 {
 490         if (root == memcg)
 491                 return true;
 492         if (!root->use_hierarchy)
 493                 return false;
 494         return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
 495 }
 496
 497 static inline bool mm_match_cgroup(struct mm_struct *mm,
 498                                    struct mem_cgroup *memcg)
 499 {
 500         struct mem_cgroup *task_memcg;
 501         bool match = false;
 502
 503         rcu_read_lock();
 504         task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 505         if (task_memcg)
 506                 match = mem_cgroup_is_descendant(task_memcg, memcg);
 507         rcu_read_unlock();
 508         return match;
 509 }
 510
 511 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
 512 ino_t page_cgroup_ino(struct page *page);
 513
 514 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 515 {
 516         if (mem_cgroup_disabled())
 517                 return true;
 518         return !!(memcg->css.flags & CSS_ONLINE);
 519 }
 520
 521 /*
 522  * For memory reclaim.
 523  */
 524 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
 525
 526 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
 527                 int zid, int nr_pages);
 528
 529 static inline
 530 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 531                 enum lru_list lru, int zone_idx)
 532 {
 533         struct mem_cgroup_per_node *mz;
 534
 535         mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 536         return mz->lru_zone_size[zone_idx][lru];
 537 }
 538
 539 void mem_cgroup_handle_over_high(void);
 540
 541 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);
 542
 543 unsigned long mem_cgroup_size(struct mem_cgroup *memcg);
 544
 545 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg,
 546                                 struct task_struct *p);
 547
 548 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg);
 549
 550 static inline void mem_cgroup_enter_user_fault(void)
 551 {
 552         WARN_ON(current->in_user_fault);
 553         current->in_user_fault = 1;
 554 }
 555
 556 static inline void mem_cgroup_exit_user_fault(void)
 557 {
 558         WARN_ON(!current->in_user_fault);
 559         current->in_user_fault = 0;
 560 }
 561
 562 static inline bool task_in_memcg_oom(struct task_struct *p)
 563 {
 564         return p->memcg_in_oom;
 565 }
 566
 567 bool mem_cgroup_oom_synchronize(bool wait);
 568 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
 569                                             struct mem_cgroup *oom_domain);
 570 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
 571
 572 #ifdef CONFIG_MEMCG_SWAP
 573 extern int do_swap_account;
 574 #endif
 575
 576 struct mem_cgroup *lock_page_memcg(struct page *page);
 577 void __unlock_page_memcg(struct mem_cgroup *memcg);
 578 void unlock_page_memcg(struct page *page);
 579
 580 /*
 581  * idx can be of type enum memcg_stat_item or node_stat_item.
 582  * Keep in sync with memcg_exact_page_state().
 583  */
 584 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
 585 {
 586         long x = atomic_long_read(&memcg->vmstats[idx]);
 587 #ifdef CONFIG_SMP
 588         if (x < 0)
 589                 x = 0;
 590 #endif
 591         return x;
 592 }
 593
 594 /*
 595  * idx can be of type enum memcg_stat_item or node_stat_item.
 596  * Keep in sync with memcg_exact_page_state().
 597  */
 598 static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
 599                                                    int idx)
 600 {
 601         long x = 0;
 602         int cpu;
 603
 604         for_each_possible_cpu(cpu)
 605                 x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
 606 #ifdef CONFIG_SMP
 607         if (x < 0)
 608                 x = 0;
 609 #endif
 610         return x;
 611 }
 612
 613 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
 614
 615 /* idx can be of type enum memcg_stat_item or node_stat_item */
 616 static inline void mod_memcg_state(struct mem_cgroup *memcg,
 617                                    int idx, int val)
 618 {
 619         unsigned long flags;
 620
 621         local_irq_save(flags);
 622         __mod_memcg_state(memcg, idx, val);
 623         local_irq_restore(flags);
 624 }
 625
 626 /**
 627  * mod_memcg_page_state - update page state statistics
 628  * @page: the page
 629  * @idx: page state item to account
 630  * @val: number of pages (positive or negative)
 631  *
 632  * The @page must be locked or the caller must use lock_page_memcg()
 633  * to prevent double accounting when the page is concurrently being
 634  * moved to another memcg:
 635  *
 636  *   lock_page(page) or lock_page_memcg(page)
 637  *   if (TestClearPageState(page))
 638  *     mod_memcg_page_state(page, state, -1);
 639  *   unlock_page(page) or unlock_page_memcg(page)
 640  *
 641  * Kernel pages are an exception to this, since they'll never move.
 642  */
 643 static inline void __mod_memcg_page_state(struct page *page,
 644                                           int idx, int val)
 645 {
 646         if (page->mem_cgroup)
 647                 __mod_memcg_state(page->mem_cgroup, idx, val);
 648 }
 649
 650 static inline void mod_memcg_page_state(struct page *page,
 651                                         int idx, int val)
 652 {
 653         if (page->mem_cgroup)
 654                 mod_memcg_state(page->mem_cgroup, idx, val);
 655 }
 656
 657 static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
 658                                               enum node_stat_item idx)
 659 {
 660         struct mem_cgroup_per_node *pn;
 661         long x;
 662
 663         if (mem_cgroup_disabled())
 664                 return node_page_state(lruvec_pgdat(lruvec), idx);
 665
 666         pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 667         x = atomic_long_read(&pn->lruvec_stat[idx]);
 668 #ifdef CONFIG_SMP
 669         if (x < 0)
 670                 x = 0;
 671 #endif
 672         return x;
 673 }
 674
 675 static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 676                                                     enum node_stat_item idx)
 677 {
 678         struct mem_cgroup_per_node *pn;
 679         long x = 0;
 680         int cpu;
 681
 682         if (mem_cgroup_disabled())
 683                 return node_page_state(lruvec_pgdat(lruvec), idx);
 684
 685         pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 686         for_each_possible_cpu(cpu)
 687                 x += per_cpu(pn->lruvec_stat_local->count[idx], cpu);
 688 #ifdef CONFIG_SMP
 689         if (x < 0)
 690                 x = 0;
 691 #endif
 692         return x;
 693 }
 694
 695 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 696                         int val);
 697 void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val);
 698 void mod_memcg_obj_state(void *p, int idx, int val);
 699
 700 static inline void mod_lruvec_state(struct lruvec *lruvec,
 701                                     enum node_stat_item idx, int val)
 702 {
 703         unsigned long flags;
 704
 705         local_irq_save(flags);
 706         __mod_lruvec_state(lruvec, idx, val);
 707         local_irq_restore(flags);
 708 }
 709
 710 static inline void __mod_lruvec_page_state(struct page *page,
 711                                            enum node_stat_item idx, int val)
 712 {
 713         pg_data_t *pgdat = page_pgdat(page);
 714         struct lruvec *lruvec;
 715
 716         /* Untracked pages have no memcg, no lruvec. Update only the node */
 717         if (!page->mem_cgroup) {
 718                 __mod_node_page_state(pgdat, idx, val);
 719                 return;
 720         }
 721
 722         lruvec = mem_cgroup_lruvec(page->mem_cgroup, pgdat);
 723         __mod_lruvec_state(lruvec, idx, val);
 724 }
 725
 726 static inline void mod_lruvec_page_state(struct page *page,
 727                                          enum node_stat_item idx, int val)
 728 {
 729         unsigned long flags;
 730
 731         local_irq_save(flags);
 732         __mod_lruvec_page_state(page, idx, val);
 733         local_irq_restore(flags);
 734 }
 735
 736 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
 737                                                 gfp_t gfp_mask,
 738                                                 unsigned long *total_scanned);
 739
 740 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
 741                           unsigned long count);
 742
 743 static inline void count_memcg_events(struct mem_cgroup *memcg,
 744                                       enum vm_event_item idx,
 745                                       unsigned long count)
 746 {
 747         unsigned long flags;
 748
 749         local_irq_save(flags);
 750         __count_memcg_events(memcg, idx, count);
 751         local_irq_restore(flags);
 752 }
 753
 754 static inline void count_memcg_page_event(struct page *page,
 755                                           enum vm_event_item idx)
 756 {
 757         if (page->mem_cgroup)
 758                 count_memcg_events(page->mem_cgroup, idx, 1);
 759 }
 760
 761 static inline void count_memcg_event_mm(struct mm_struct *mm,
 762                                         enum vm_event_item idx)
 763 {
 764         struct mem_cgroup *memcg;
 765
 766         if (mem_cgroup_disabled())
 767                 return;
 768
 769         rcu_read_lock();
 770         memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 771         if (likely(memcg))
 772                 count_memcg_events(memcg, idx, 1);
 773         rcu_read_unlock();
 774 }
 775
 776 static inline void memcg_memory_event(struct mem_cgroup *memcg,
 777                                       enum memcg_memory_event event)
 778 {
 779         atomic_long_inc(&memcg->memory_events_local[event]);
 780         cgroup_file_notify(&memcg->events_local_file);
 781
 782         do {
 783                 atomic_long_inc(&memcg->memory_events[event]);
 784                 cgroup_file_notify(&memcg->events_file);
 785
 786                 if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
 787                         break;
 788         } while ((memcg = parent_mem_cgroup(memcg)) &&
 789                  !mem_cgroup_is_root(memcg));
 790 }
 791
 792 static inline void memcg_memory_event_mm(struct mm_struct *mm,
 793                                          enum memcg_memory_event event)
 794 {
 795         struct mem_cgroup *memcg;
 796
 797         if (mem_cgroup_disabled())
 798                 return;
 799
 800         rcu_read_lock();
 801         memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
 802         if (likely(memcg))
 803                 memcg_memory_event(memcg, event);
 804         rcu_read_unlock();
 805 }
 806
 807 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 808 void mem_cgroup_split_huge_fixup(struct page *head);
 809 #endif
 810
 811 #else /* CONFIG_MEMCG */
 812
 813 #define MEM_CGROUP_ID_SHIFT     0
 814 #define MEM_CGROUP_ID_MAX       0
 815
 816 struct mem_cgroup;
 817
 818 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
 819 {
 820         return true;
 821 }
 822
 823 static inline bool mem_cgroup_disabled(void)
 824 {
 825         return true;
 826 }
 827
 828 static inline void memcg_memory_event(struct mem_cgroup *memcg,
 829                                       enum memcg_memory_event event)
 830 {
 831 }
 832
 833 static inline void memcg_memory_event_mm(struct mm_struct *mm,
 834                                          enum memcg_memory_event event)
 835 {
 836 }
 837
 838 static inline unsigned long mem_cgroup_protection(struct mem_cgroup *memcg,
 839                                                   bool in_low_reclaim)
 840 {
 841         return 0;
 842 }
 843
 844 static inline enum mem_cgroup_protection mem_cgroup_protected(
 845         struct mem_cgroup *root, struct mem_cgroup *memcg)
 846 {
 847         return MEMCG_PROT_NONE;
 848 }
 849
 850 static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
 851                                         gfp_t gfp_mask,
 852                                         struct mem_cgroup **memcgp,
 853                                         bool compound)
 854 {
 855         *memcgp = NULL;
 856         return 0;
 857 }
 858
 859 static inline int mem_cgroup_try_charge_delay(struct page *page,
 860                                               struct mm_struct *mm,
 861                                               gfp_t gfp_mask,
 862                                               struct mem_cgroup **memcgp,
 863                                               bool compound)
 864 {
 865         *memcgp = NULL;
 866         return 0;
 867 }
 868
 869 static inline void mem_cgroup_commit_charge(struct page *page,
 870                                             struct mem_cgroup *memcg,
 871                                             bool lrucare, bool compound)
 872 {
 873 }
 874
 875 static inline void mem_cgroup_cancel_charge(struct page *page,
 876                                             struct mem_cgroup *memcg,
 877                                             bool compound)
 878 {
 879 }
 880
 881 static inline void mem_cgroup_uncharge(struct page *page)
 882 {
 883 }
 884
 885 static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
 886 {
 887 }
 888
 889 static inline void mem_cgroup_migrate(struct page *old, struct page *new)
 890 {
 891 }
 892
 893 static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
 894                                                struct pglist_data *pgdat)
 895 {
 896         return &pgdat->__lruvec;
 897 }
 898
 899 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
 900                                                     struct pglist_data *pgdat)
 901 {
 902         return &pgdat->__lruvec;
 903 }
 904
 905 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
 906 {
 907         return NULL;
 908 }
 909
 910 static inline bool mm_match_cgroup(struct mm_struct *mm,
 911                 struct mem_cgroup *memcg)
 912 {
 913         return true;
 914 }
 915
 916 static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
 917 {
 918         return NULL;
 919 }
 920
 921 static inline struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
 922 {
 923         return NULL;
 924 }
 925
 926 static inline void mem_cgroup_put(struct mem_cgroup *memcg)
 927 {
 928 }
 929
 930 static inline struct mem_cgroup *
 931 mem_cgroup_iter(struct mem_cgroup *root,
 932                 struct mem_cgroup *prev,
 933                 struct mem_cgroup_reclaim_cookie *reclaim)
 934 {
 935         return NULL;
 936 }
 937
 938 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
 939                                          struct mem_cgroup *prev)
 940 {
 941 }
 942
 943 static inline int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
 944                 int (*fn)(struct task_struct *, void *), void *arg)
 945 {
 946         return 0;
 947 }
 948
 949 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
 950 {
 951         return 0;
 952 }
 953
 954 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
 955 {
 956         WARN_ON_ONCE(id);
 957         /* XXX: This should always return root_mem_cgroup */
 958         return NULL;
 959 }
 960
 961 static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
 962 {
 963         return NULL;
 964 }
 965
 966 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
 967 {
 968         return NULL;
 969 }
 970
 971 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
 972 {
 973         return true;
 974 }
 975
 976 static inline
 977 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
 978                 enum lru_list lru, int zone_idx)
 979 {
 980         return 0;
 981 }
 982
 983 static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
 984 {
 985         return 0;
 986 }
 987
 988 static inline unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
 989 {
 990         return 0;
 991 }
 992
 993 static inline void
 994 mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
 995 {
 996 }
 997
 998 static inline void
 999 mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1000 {
1001 }
1002
1003 static inline struct mem_cgroup *lock_page_memcg(struct page *page)
1004 {
1005         return NULL;
1006 }
1007
1008 static inline void __unlock_page_memcg(struct mem_cgroup *memcg)
1009 {
1010 }
1011
1012 static inline void unlock_page_memcg(struct page *page)
1013 {
1014 }
1015
1016 static inline void mem_cgroup_handle_over_high(void)
1017 {
1018 }
1019
1020 static inline void mem_cgroup_enter_user_fault(void)
1021 {
1022 }
1023
1024 static inline void mem_cgroup_exit_user_fault(void)
1025 {
1026 }
1027
1028 static inline bool task_in_memcg_oom(struct task_struct *p)
1029 {
1030         return false;
1031 }
1032
1033 static inline bool mem_cgroup_oom_synchronize(bool wait)
1034 {
1035         return false;
1036 }
1037
1038 static inline struct mem_cgroup *mem_cgroup_get_oom_group(
1039         struct task_struct *victim, struct mem_cgroup *oom_domain)
1040 {
1041         return NULL;
1042 }
1043
1044 static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
1045 {
1046 }
1047
1048 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
1049 {
1050         return 0;
1051 }
1052
1053 static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
1054                                                    int idx)
1055 {
1056         return 0;
1057 }
1058
1059 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
1060                                      int idx,
1061                                      int nr)
1062 {
1063 }
1064
1065 static inline void mod_memcg_state(struct mem_cgroup *memcg,
1066                                    int idx,
1067                                    int nr)
1068 {
1069 }
1070
1071 static inline void __mod_memcg_page_state(struct page *page,
1072                                           int idx,
1073                                           int nr)
1074 {
1075 }
1076
1077 static inline void mod_memcg_page_state(struct page *page,
1078                                         int idx,
1079                                         int nr)
1080 {
1081 }
1082
1083 static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
1084                                               enum node_stat_item idx)
1085 {
1086         return node_page_state(lruvec_pgdat(lruvec), idx);
1087 }
1088
1089 static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
1090                                                     enum node_stat_item idx)
1091 {
1092         return node_page_state(lruvec_pgdat(lruvec), idx);
1093 }
1094
1095 static inline void __mod_lruvec_state(struct lruvec *lruvec,
1096                                       enum node_stat_item idx, int val)
1097 {
1098         __mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
1099 }
1100
1101 static inline void mod_lruvec_state(struct lruvec *lruvec,
1102                                     enum node_stat_item idx, int val)
1103 {
1104         mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
1105 }
1106
1107 static inline void __mod_lruvec_page_state(struct page *page,
1108                                            enum node_stat_item idx, int val)
1109 {
1110         __mod_node_page_state(page_pgdat(page), idx, val);
1111 }
1112
1113 static inline void mod_lruvec_page_state(struct page *page,
1114                                          enum node_stat_item idx, int val)
1115 {
1116         mod_node_page_state(page_pgdat(page), idx, val);
1117 }
1118
1119 static inline void __mod_lruvec_slab_state(void *p, enum node_stat_item idx,
1120                                            int val)
1121 {
1122         struct page *page = virt_to_head_page(p);
1123
1124         __mod_node_page_state(page_pgdat(page), idx, val);
1125 }
1126
1127 static inline void mod_memcg_obj_state(void *p, int idx, int val)
1128 {
1129 }
1130
1131 static inline
1132 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
1133                                             gfp_t gfp_mask,
1134                                             unsigned long *total_scanned)
1135 {
1136         return 0;
1137 }
1138
1139 static inline void mem_cgroup_split_huge_fixup(struct page *head)
1140 {
1141 }
1142
1143 static inline void count_memcg_events(struct mem_cgroup *memcg,
1144                                       enum vm_event_item idx,
1145                                       unsigned long count)
1146 {
1147 }
1148
1149 static inline void __count_memcg_events(struct mem_cgroup *memcg,
1150                                         enum vm_event_item idx,
1151                                         unsigned long count)
1152 {
1153 }
1154
1155 static inline void count_memcg_page_event(struct page *page,
1156                                           int idx)
1157 {
1158 }
1159
1160 static inline
1161 void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
1162 {
1163 }
1164 #endif /* CONFIG_MEMCG */
1165
1166 /* idx can be of type enum memcg_stat_item or node_stat_item */
1167 static inline void __inc_memcg_state(struct mem_cgroup *memcg,
1168                                      int idx)
1169 {
1170         __mod_memcg_state(memcg, idx, 1);
1171 }
1172
1173 /* idx can be of type enum memcg_stat_item or node_stat_item */
1174 static inline void __dec_memcg_state(struct mem_cgroup *memcg,
1175                                      int idx)
1176 {
1177         __mod_memcg_state(memcg, idx, -1);
1178 }
1179
1180 /* idx can be of type enum memcg_stat_item or node_stat_item */
1181 static inline void __inc_memcg_page_state(struct page *page,
1182                                           int idx)
1183 {
1184         __mod_memcg_page_state(page, idx, 1);
1185 }
1186
1187 /* idx can be of type enum memcg_stat_item or node_stat_item */
1188 static inline void __dec_memcg_page_state(struct page *page,
1189                                           int idx)
1190 {
1191         __mod_memcg_page_state(page, idx, -1);
1192 }
1193
1194 static inline void __inc_lruvec_state(struct lruvec *lruvec,
1195                                       enum node_stat_item idx)
1196 {
1197         __mod_lruvec_state(lruvec, idx, 1);
1198 }
1199
1200 static inline void __dec_lruvec_state(struct lruvec *lruvec,
1201                                       enum node_stat_item idx)
1202 {
1203         __mod_lruvec_state(lruvec, idx, -1);
1204 }
1205
1206 static inline void __inc_lruvec_page_state(struct page *page,
1207                                            enum node_stat_item idx)
1208 {
1209         __mod_lruvec_page_state(page, idx, 1);
1210 }
1211
1212 static inline void __dec_lruvec_page_state(struct page *page,
1213                                            enum node_stat_item idx)
1214 {
1215         __mod_lruvec_page_state(page, idx, -1);
1216 }
1217
1218 static inline void __inc_lruvec_slab_state(void *p, enum node_stat_item idx)
1219 {
1220         __mod_lruvec_slab_state(p, idx, 1);
1221 }
1222
1223 static inline void __dec_lruvec_slab_state(void *p, enum node_stat_item idx)
1224 {
1225         __mod_lruvec_slab_state(p, idx, -1);
1226 }
1227
1228 /* idx can be of type enum memcg_stat_item or node_stat_item */
1229 static inline void inc_memcg_state(struct mem_cgroup *memcg,
1230                                    int idx)
1231 {
1232         mod_memcg_state(memcg, idx, 1);
1233 }
1234
1235 /* idx can be of type enum memcg_stat_item or node_stat_item */
1236 static inline void dec_memcg_state(struct mem_cgroup *memcg,
1237                                    int idx)
1238 {
1239         mod_memcg_state(memcg, idx, -1);
1240 }
1241
1242 /* idx can be of type enum memcg_stat_item or node_stat_item */
1243 static inline void inc_memcg_page_state(struct page *page,
1244                                         int idx)
1245 {
1246         mod_memcg_page_state(page, idx, 1);
1247 }
1248
1249 /* idx can be of type enum memcg_stat_item or node_stat_item */
1250 static inline void dec_memcg_page_state(struct page *page,
1251                                         int idx)
1252 {
1253         mod_memcg_page_state(page, idx, -1);
1254 }
1255
1256 static inline void inc_lruvec_state(struct lruvec *lruvec,
1257                                     enum node_stat_item idx)
1258 {
1259         mod_lruvec_state(lruvec, idx, 1);
1260 }
1261
1262 static inline void dec_lruvec_state(struct lruvec *lruvec,
1263                                     enum node_stat_item idx)
1264 {
1265         mod_lruvec_state(lruvec, idx, -1);
1266 }
1267
1268 static inline void inc_lruvec_page_state(struct page *page,
1269                                          enum node_stat_item idx)
1270 {
1271         mod_lruvec_page_state(page, idx, 1);
1272 }
1273
1274 static inline void dec_lruvec_page_state(struct page *page,
1275                                          enum node_stat_item idx)
1276 {
1277         mod_lruvec_page_state(page, idx, -1);
1278 }
1279
1280 #ifdef CONFIG_CGROUP_WRITEBACK
1281
1282 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
1283 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
1284                          unsigned long *pheadroom, unsigned long *pdirty,
1285                          unsigned long *pwriteback);
1286
1287 void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
1288                                              struct bdi_writeback *wb);
1289
1290 static inline void mem_cgroup_track_foreign_dirty(struct page *page,
1291                                                   struct bdi_writeback *wb)
1292 {
1293         if (mem_cgroup_disabled())
1294                 return;
1295
1296         if (unlikely(&page->mem_cgroup->css != wb->memcg_css))
1297                 mem_cgroup_track_foreign_dirty_slowpath(page, wb);
1298 }
1299
1300 void mem_cgroup_flush_foreign(struct bdi_writeback *wb);
1301
1302 #else   /* CONFIG_CGROUP_WRITEBACK */
1303
1304 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
1305 {
1306         return NULL;
1307 }
1308
1309 static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
1310                                        unsigned long *pfilepages,
1311                                        unsigned long *pheadroom,
1312                                        unsigned long *pdirty,
1313                                        unsigned long *pwriteback)
1314 {
1315 }
1316
1317 static inline void mem_cgroup_track_foreign_dirty(struct page *page,
1318                                                   struct bdi_writeback *wb)
1319 {
1320 }
1321
1322 static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
1323 {
1324 }
1325
1326 #endif  /* CONFIG_CGROUP_WRITEBACK */
1327
1328 struct sock;
1329 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
1330 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
1331 #ifdef CONFIG_MEMCG
1332 extern struct static_key_false memcg_sockets_enabled_key;
1333 #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
1334 void mem_cgroup_sk_alloc(struct sock *sk);
1335 void mem_cgroup_sk_free(struct sock *sk);
1336 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
1337 {
1338         if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)
1339                 return true;
1340         do {
1341                 if (time_before(jiffies, memcg->socket_pressure))
1342                         return true;
1343         } while ((memcg = parent_mem_cgroup(memcg)));
1344         return false;
1345 }
1346
1347 extern int memcg_expand_shrinker_maps(int new_id);
1348
1349 extern void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
1350                                    int nid, int shrinker_id);
1351 #else
1352 #define mem_cgroup_sockets_enabled 0
1353 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
1354 static inline void mem_cgroup_sk_free(struct sock *sk) { };
1355 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
1356 {
1357         return false;
1358 }
1359
1360 static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
1361                                           int nid, int shrinker_id)
1362 {
1363 }
1364 #endif
1365
1366 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
1367 void memcg_kmem_put_cache(struct kmem_cache *cachep);
1368
1369 #ifdef CONFIG_MEMCG_KMEM
1370 int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
1371                         unsigned int nr_pages);
1372 void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages);
1373 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order);
1374 void __memcg_kmem_uncharge_page(struct page *page, int order);
1375
1376 extern struct static_key_false memcg_kmem_enabled_key;
1377 extern struct workqueue_struct *memcg_kmem_cache_wq;
1378
1379 extern int memcg_nr_cache_ids;
1380 void memcg_get_cache_ids(void);
1381 void memcg_put_cache_ids(void);
1382
1383 /*
1384  * Helper macro to loop through all memcg-specific caches. Callers must still
1385  * check if the cache is valid (it is either valid or NULL).
1386  * the slab_mutex must be held when looping through those caches
1387  */
1388 #define for_each_memcg_cache_index(_idx)        \
1389         for ((_idx) = 0; (_idx) < memcg_nr_cache_ids; (_idx)++)
1390
1391 static inline bool memcg_kmem_enabled(void)
1392 {
1393         return static_branch_unlikely(&memcg_kmem_enabled_key);
1394 }
1395
1396 static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
1397                                          int order)
1398 {
1399         if (memcg_kmem_enabled())
1400                 return __memcg_kmem_charge_page(page, gfp, order);
1401         return 0;
1402 }
1403
1404 static inline void memcg_kmem_uncharge_page(struct page *page, int order)
1405 {
1406         if (memcg_kmem_enabled())
1407                 __memcg_kmem_uncharge_page(page, order);
1408 }
1409
1410 static inline int memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
1411                                     unsigned int nr_pages)
1412 {
1413         if (memcg_kmem_enabled())
1414                 return __memcg_kmem_charge(memcg, gfp, nr_pages);
1415         return 0;
1416 }
1417
1418 static inline void memcg_kmem_uncharge(struct mem_cgroup *memcg,
1419                                        unsigned int nr_pages)
1420 {
1421         if (memcg_kmem_enabled())
1422                 __memcg_kmem_uncharge(memcg, nr_pages);
1423 }
1424
1425 /*
1426  * helper for accessing a memcg's index. It will be used as an index in the
1427  * child cache array in kmem_cache, and also to derive its name. This function
1428  * will return -1 when this is not a kmem-limited memcg.
1429  */
1430 static inline int memcg_cache_id(struct mem_cgroup *memcg)
1431 {
1432         return memcg ? memcg->kmemcg_id : -1;
1433 }
1434
1435 struct mem_cgroup *mem_cgroup_from_obj(void *p);
1436
1437 #else
1438
1439 static inline int memcg_kmem_charge_page(struct page *page, gfp_t gfp,
1440                                          int order)
1441 {
1442         return 0;
1443 }
1444
1445 static inline void memcg_kmem_uncharge_page(struct page *page, int order)
1446 {
1447 }
1448
1449 static inline int __memcg_kmem_charge_page(struct page *page, gfp_t gfp,
1450                                            int order)
1451 {
1452         return 0;
1453 }
1454
1455 static inline void __memcg_kmem_uncharge_page(struct page *page, int order)
1456 {
1457 }
1458
1459 #define for_each_memcg_cache_index(_idx)        \
1460         for (; NULL; )
1461
1462 static inline bool memcg_kmem_enabled(void)
1463 {
1464         return false;
1465 }
1466
1467 static inline int memcg_cache_id(struct mem_cgroup *memcg)
1468 {
1469         return -1;
1470 }
1471
1472 static inline void memcg_get_cache_ids(void)
1473 {
1474 }
1475
1476 static inline void memcg_put_cache_ids(void)
1477 {
1478 }
1479
1480 static inline struct mem_cgroup *mem_cgroup_from_obj(void *p)
1481 {
1482        return NULL;
1483 }
1484
1485 #endif /* CONFIG_MEMCG_KMEM */
1486
1487 #endif /* _LINUX_MEMCONTROL_H */