xref: /linux-6.15/include/linux/memcontrol.h (revision 181ea40a)
1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* memcontrol.h - Memory Controller
3  *
4  * Copyright IBM Corporation, 2007
5  * Author Balbir Singh <[email protected]>
6  *
7  * Copyright 2007 OpenVZ SWsoft Inc
8  * Author: Pavel Emelianov <[email protected]>
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 	int priority;
62 	unsigned int generation;
63 };
64 
65 #ifdef CONFIG_MEMCG
66 
67 #define MEM_CGROUP_ID_SHIFT	16
68 #define MEM_CGROUP_ID_MAX	USHRT_MAX
69 
70 struct mem_cgroup_id {
71 	int id;
72 	refcount_t ref;
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 memcg_vmstats_percpu {
89 	long stat[MEMCG_NR_STAT];
90 	unsigned long events[NR_VM_EVENT_ITEMS];
91 	unsigned long nr_page_events;
92 	unsigned long targets[MEM_CGROUP_NTARGETS];
93 };
94 
95 struct mem_cgroup_reclaim_iter {
96 	struct mem_cgroup *position;
97 	/* scan generation, increased every round-trip */
98 	unsigned int generation;
99 };
100 
101 struct lruvec_stat {
102 	long count[NR_VM_NODE_STAT_ITEMS];
103 };
104 
105 /*
106  * Bitmap of shrinker::id corresponding to memcg-aware shrinkers,
107  * which have elements charged to this memcg.
108  */
109 struct memcg_shrinker_map {
110 	struct rcu_head rcu;
111 	unsigned long map[0];
112 };
113 
114 /*
115  * per-zone information in memory controller.
116  */
117 struct mem_cgroup_per_node {
118 	struct lruvec		lruvec;
119 
120 	/* Legacy local VM stats */
121 	struct lruvec_stat __percpu *lruvec_stat_local;
122 
123 	/* Subtree VM stats (batched updates) */
124 	struct lruvec_stat __percpu *lruvec_stat_cpu;
125 	atomic_long_t		lruvec_stat[NR_VM_NODE_STAT_ITEMS];
126 
127 	unsigned long		lru_zone_size[MAX_NR_ZONES][NR_LRU_LISTS];
128 
129 	struct mem_cgroup_reclaim_iter	iter[DEF_PRIORITY + 1];
130 
131 	struct memcg_shrinker_map __rcu	*shrinker_map;
132 
133 	struct rb_node		tree_node;	/* RB tree node */
134 	unsigned long		usage_in_excess;/* Set to the value by which */
135 						/* the soft limit is exceeded*/
136 	bool			on_tree;
137 	bool			congested;	/* memcg has many dirty pages */
138 						/* backed by a congested BDI */
139 
140 	struct mem_cgroup	*memcg;		/* Back pointer, we cannot */
141 						/* use container_of	   */
142 };
143 
144 struct mem_cgroup_threshold {
145 	struct eventfd_ctx *eventfd;
146 	unsigned long threshold;
147 };
148 
149 /* For threshold */
150 struct mem_cgroup_threshold_ary {
151 	/* An array index points to threshold just below or equal to usage. */
152 	int current_threshold;
153 	/* Size of entries[] */
154 	unsigned int size;
155 	/* Array of thresholds */
156 	struct mem_cgroup_threshold entries[0];
157 };
158 
159 struct mem_cgroup_thresholds {
160 	/* Primary thresholds array */
161 	struct mem_cgroup_threshold_ary *primary;
162 	/*
163 	 * Spare threshold array.
164 	 * This is needed to make mem_cgroup_unregister_event() "never fail".
165 	 * It must be able to store at least primary->size - 1 entries.
166 	 */
167 	struct mem_cgroup_threshold_ary *spare;
168 };
169 
170 enum memcg_kmem_state {
171 	KMEM_NONE,
172 	KMEM_ALLOCATED,
173 	KMEM_ONLINE,
174 };
175 
176 #if defined(CONFIG_SMP)
177 struct memcg_padding {
178 	char x[0];
179 } ____cacheline_internodealigned_in_smp;
180 #define MEMCG_PADDING(name)      struct memcg_padding name;
181 #else
182 #define MEMCG_PADDING(name)
183 #endif
184 
185 /*
186  * Remember four most recent foreign writebacks with dirty pages in this
187  * cgroup.  Inode sharing is expected to be uncommon and, even if we miss
188  * one in a given round, we're likely to catch it later if it keeps
189  * foreign-dirtying, so a fairly low count should be enough.
190  *
191  * See mem_cgroup_track_foreign_dirty_slowpath() for details.
192  */
193 #define MEMCG_CGWB_FRN_CNT	4
194 
195 struct memcg_cgwb_frn {
196 	u64 bdi_id;			/* bdi->id of the foreign inode */
197 	int memcg_id;			/* memcg->css.id of foreign inode */
198 	u64 at;				/* jiffies_64 at the time of dirtying */
199 	struct wb_completion done;	/* tracks in-flight foreign writebacks */
200 };
201 
202 /*
203  * The memory controller data structure. The memory controller controls both
204  * page cache and RSS per cgroup. We would eventually like to provide
205  * statistics based on the statistics developed by Rik Van Riel for clock-pro,
206  * to help the administrator determine what knobs to tune.
207  */
208 struct mem_cgroup {
209 	struct cgroup_subsys_state css;
210 
211 	/* Private memcg ID. Used to ID objects that outlive the cgroup */
212 	struct mem_cgroup_id id;
213 
214 	/* Accounted resources */
215 	struct page_counter memory;
216 	struct page_counter swap;
217 
218 	/* Legacy consumer-oriented counters */
219 	struct page_counter memsw;
220 	struct page_counter kmem;
221 	struct page_counter tcpmem;
222 
223 	/* Upper bound of normal memory consumption range */
224 	unsigned long high;
225 
226 	/* Range enforcement for interrupt charges */
227 	struct work_struct high_work;
228 
229 	unsigned long soft_limit;
230 
231 	/* vmpressure notifications */
232 	struct vmpressure vmpressure;
233 
234 	/*
235 	 * Should the accounting and control be hierarchical, per subtree?
236 	 */
237 	bool use_hierarchy;
238 
239 	/*
240 	 * Should the OOM killer kill all belonging tasks, had it kill one?
241 	 */
242 	bool oom_group;
243 
244 	/* protected by memcg_oom_lock */
245 	bool		oom_lock;
246 	int		under_oom;
247 
248 	int	swappiness;
249 	/* OOM-Killer disable */
250 	int		oom_kill_disable;
251 
252 	/* memory.events and memory.events.local */
253 	struct cgroup_file events_file;
254 	struct cgroup_file events_local_file;
255 
256 	/* handle for "memory.swap.events" */
257 	struct cgroup_file swap_events_file;
258 
259 	/* protect arrays of thresholds */
260 	struct mutex thresholds_lock;
261 
262 	/* thresholds for memory usage. RCU-protected */
263 	struct mem_cgroup_thresholds thresholds;
264 
265 	/* thresholds for mem+swap usage. RCU-protected */
266 	struct mem_cgroup_thresholds memsw_thresholds;
267 
268 	/* For oom notifier event fd */
269 	struct list_head oom_notify;
270 
271 	/*
272 	 * Should we move charges of a task when a task is moved into this
273 	 * mem_cgroup ? And what type of charges should we move ?
274 	 */
275 	unsigned long move_charge_at_immigrate;
276 	/* taken only while moving_account > 0 */
277 	spinlock_t		move_lock;
278 	unsigned long		move_lock_flags;
279 
280 	MEMCG_PADDING(_pad1_);
281 
282 	/*
283 	 * set > 0 if pages under this cgroup are moving to other cgroup.
284 	 */
285 	atomic_t		moving_account;
286 	struct task_struct	*move_lock_task;
287 
288 	/* Legacy local VM stats and events */
289 	struct memcg_vmstats_percpu __percpu *vmstats_local;
290 
291 	/* Subtree VM stats and events (batched updates) */
292 	struct memcg_vmstats_percpu __percpu *vmstats_percpu;
293 
294 	MEMCG_PADDING(_pad2_);
295 
296 	atomic_long_t		vmstats[MEMCG_NR_STAT];
297 	atomic_long_t		vmevents[NR_VM_EVENT_ITEMS];
298 
299 	/* memory.events */
300 	atomic_long_t		memory_events[MEMCG_NR_MEMORY_EVENTS];
301 	atomic_long_t		memory_events_local[MEMCG_NR_MEMORY_EVENTS];
302 
303 	unsigned long		socket_pressure;
304 
305 	/* Legacy tcp memory accounting */
306 	bool			tcpmem_active;
307 	int			tcpmem_pressure;
308 
309 #ifdef CONFIG_MEMCG_KMEM
310         /* Index in the kmem_cache->memcg_params.memcg_caches array */
311 	int kmemcg_id;
312 	enum memcg_kmem_state kmem_state;
313 	struct list_head kmem_caches;
314 #endif
315 
316 	int last_scanned_node;
317 #if MAX_NUMNODES > 1
318 	nodemask_t	scan_nodes;
319 	atomic_t	numainfo_events;
320 	atomic_t	numainfo_updating;
321 #endif
322 
323 #ifdef CONFIG_CGROUP_WRITEBACK
324 	struct list_head cgwb_list;
325 	struct wb_domain cgwb_domain;
326 	struct memcg_cgwb_frn cgwb_frn[MEMCG_CGWB_FRN_CNT];
327 #endif
328 
329 	/* List of events which userspace want to receive */
330 	struct list_head event_list;
331 	spinlock_t event_list_lock;
332 
333 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
334 	struct deferred_split deferred_split_queue;
335 #endif
336 
337 	struct mem_cgroup_per_node *nodeinfo[0];
338 	/* WARNING: nodeinfo must be the last member here */
339 };
340 
341 /*
342  * size of first charge trial. "32" comes from vmscan.c's magic value.
343  * TODO: maybe necessary to use big numbers in big irons.
344  */
345 #define MEMCG_CHARGE_BATCH 32U
346 
347 extern struct mem_cgroup *root_mem_cgroup;
348 
349 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
350 {
351 	return (memcg == root_mem_cgroup);
352 }
353 
354 static inline bool mem_cgroup_disabled(void)
355 {
356 	return !cgroup_subsys_enabled(memory_cgrp_subsys);
357 }
358 
359 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
360 						struct mem_cgroup *memcg);
361 
362 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
363 			  gfp_t gfp_mask, struct mem_cgroup **memcgp,
364 			  bool compound);
365 int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm,
366 			  gfp_t gfp_mask, struct mem_cgroup **memcgp,
367 			  bool compound);
368 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
369 			      bool lrucare, bool compound);
370 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
371 		bool compound);
372 void mem_cgroup_uncharge(struct page *page);
373 void mem_cgroup_uncharge_list(struct list_head *page_list);
374 
375 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage);
376 
377 static struct mem_cgroup_per_node *
378 mem_cgroup_nodeinfo(struct mem_cgroup *memcg, int nid)
379 {
380 	return memcg->nodeinfo[nid];
381 }
382 
383 /**
384  * mem_cgroup_lruvec - get the lru list vector for a node or a memcg zone
385  * @node: node of the wanted lruvec
386  * @memcg: memcg of the wanted lruvec
387  *
388  * Returns the lru list vector holding pages for a given @node or a given
389  * @memcg and @zone. This can be the node lruvec, if the memory controller
390  * is disabled.
391  */
392 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
393 				struct mem_cgroup *memcg)
394 {
395 	struct mem_cgroup_per_node *mz;
396 	struct lruvec *lruvec;
397 
398 	if (mem_cgroup_disabled()) {
399 		lruvec = node_lruvec(pgdat);
400 		goto out;
401 	}
402 
403 	mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
404 	lruvec = &mz->lruvec;
405 out:
406 	/*
407 	 * Since a node can be onlined after the mem_cgroup was created,
408 	 * we have to be prepared to initialize lruvec->pgdat here;
409 	 * and if offlined then reonlined, we need to reinitialize it.
410 	 */
411 	if (unlikely(lruvec->pgdat != pgdat))
412 		lruvec->pgdat = pgdat;
413 	return lruvec;
414 }
415 
416 struct lruvec *mem_cgroup_page_lruvec(struct page *, struct pglist_data *);
417 
418 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
419 
420 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
421 
422 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page);
423 
424 static inline
425 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css){
426 	return css ? container_of(css, struct mem_cgroup, css) : NULL;
427 }
428 
429 static inline void mem_cgroup_put(struct mem_cgroup *memcg)
430 {
431 	if (memcg)
432 		css_put(&memcg->css);
433 }
434 
435 #define mem_cgroup_from_counter(counter, member)	\
436 	container_of(counter, struct mem_cgroup, member)
437 
438 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *,
439 				   struct mem_cgroup *,
440 				   struct mem_cgroup_reclaim_cookie *);
441 void mem_cgroup_iter_break(struct mem_cgroup *, struct mem_cgroup *);
442 int mem_cgroup_scan_tasks(struct mem_cgroup *,
443 			  int (*)(struct task_struct *, void *), void *);
444 
445 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
446 {
447 	if (mem_cgroup_disabled())
448 		return 0;
449 
450 	return memcg->id.id;
451 }
452 struct mem_cgroup *mem_cgroup_from_id(unsigned short id);
453 
454 static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
455 {
456 	return mem_cgroup_from_css(seq_css(m));
457 }
458 
459 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
460 {
461 	struct mem_cgroup_per_node *mz;
462 
463 	if (mem_cgroup_disabled())
464 		return NULL;
465 
466 	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
467 	return mz->memcg;
468 }
469 
470 /**
471  * parent_mem_cgroup - find the accounting parent of a memcg
472  * @memcg: memcg whose parent to find
473  *
474  * Returns the parent memcg, or NULL if this is the root or the memory
475  * controller is in legacy no-hierarchy mode.
476  */
477 static inline struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
478 {
479 	if (!memcg->memory.parent)
480 		return NULL;
481 	return mem_cgroup_from_counter(memcg->memory.parent, memory);
482 }
483 
484 static inline bool mem_cgroup_is_descendant(struct mem_cgroup *memcg,
485 			      struct mem_cgroup *root)
486 {
487 	if (root == memcg)
488 		return true;
489 	if (!root->use_hierarchy)
490 		return false;
491 	return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
492 }
493 
494 static inline bool mm_match_cgroup(struct mm_struct *mm,
495 				   struct mem_cgroup *memcg)
496 {
497 	struct mem_cgroup *task_memcg;
498 	bool match = false;
499 
500 	rcu_read_lock();
501 	task_memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
502 	if (task_memcg)
503 		match = mem_cgroup_is_descendant(task_memcg, memcg);
504 	rcu_read_unlock();
505 	return match;
506 }
507 
508 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page);
509 ino_t page_cgroup_ino(struct page *page);
510 
511 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
512 {
513 	if (mem_cgroup_disabled())
514 		return true;
515 	return !!(memcg->css.flags & CSS_ONLINE);
516 }
517 
518 /*
519  * For memory reclaim.
520  */
521 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg);
522 
523 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
524 		int zid, int nr_pages);
525 
526 static inline
527 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
528 		enum lru_list lru, int zone_idx)
529 {
530 	struct mem_cgroup_per_node *mz;
531 
532 	mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
533 	return mz->lru_zone_size[zone_idx][lru];
534 }
535 
536 void mem_cgroup_handle_over_high(void);
537 
538 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg);
539 
540 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg,
541 				struct task_struct *p);
542 
543 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg);
544 
545 static inline void mem_cgroup_enter_user_fault(void)
546 {
547 	WARN_ON(current->in_user_fault);
548 	current->in_user_fault = 1;
549 }
550 
551 static inline void mem_cgroup_exit_user_fault(void)
552 {
553 	WARN_ON(!current->in_user_fault);
554 	current->in_user_fault = 0;
555 }
556 
557 static inline bool task_in_memcg_oom(struct task_struct *p)
558 {
559 	return p->memcg_in_oom;
560 }
561 
562 bool mem_cgroup_oom_synchronize(bool wait);
563 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
564 					    struct mem_cgroup *oom_domain);
565 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
566 
567 #ifdef CONFIG_MEMCG_SWAP
568 extern int do_swap_account;
569 #endif
570 
571 struct mem_cgroup *lock_page_memcg(struct page *page);
572 void __unlock_page_memcg(struct mem_cgroup *memcg);
573 void unlock_page_memcg(struct page *page);
574 
575 /*
576  * idx can be of type enum memcg_stat_item or node_stat_item.
577  * Keep in sync with memcg_exact_page_state().
578  */
579 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
580 {
581 	long x = atomic_long_read(&memcg->vmstats[idx]);
582 #ifdef CONFIG_SMP
583 	if (x < 0)
584 		x = 0;
585 #endif
586 	return x;
587 }
588 
589 /*
590  * idx can be of type enum memcg_stat_item or node_stat_item.
591  * Keep in sync with memcg_exact_page_state().
592  */
593 static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
594 						   int idx)
595 {
596 	long x = 0;
597 	int cpu;
598 
599 	for_each_possible_cpu(cpu)
600 		x += per_cpu(memcg->vmstats_local->stat[idx], cpu);
601 #ifdef CONFIG_SMP
602 	if (x < 0)
603 		x = 0;
604 #endif
605 	return x;
606 }
607 
608 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val);
609 
610 /* idx can be of type enum memcg_stat_item or node_stat_item */
611 static inline void mod_memcg_state(struct mem_cgroup *memcg,
612 				   int idx, int val)
613 {
614 	unsigned long flags;
615 
616 	local_irq_save(flags);
617 	__mod_memcg_state(memcg, idx, val);
618 	local_irq_restore(flags);
619 }
620 
621 /**
622  * mod_memcg_page_state - update page state statistics
623  * @page: the page
624  * @idx: page state item to account
625  * @val: number of pages (positive or negative)
626  *
627  * The @page must be locked or the caller must use lock_page_memcg()
628  * to prevent double accounting when the page is concurrently being
629  * moved to another memcg:
630  *
631  *   lock_page(page) or lock_page_memcg(page)
632  *   if (TestClearPageState(page))
633  *     mod_memcg_page_state(page, state, -1);
634  *   unlock_page(page) or unlock_page_memcg(page)
635  *
636  * Kernel pages are an exception to this, since they'll never move.
637  */
638 static inline void __mod_memcg_page_state(struct page *page,
639 					  int idx, int val)
640 {
641 	if (page->mem_cgroup)
642 		__mod_memcg_state(page->mem_cgroup, idx, val);
643 }
644 
645 static inline void mod_memcg_page_state(struct page *page,
646 					int idx, int val)
647 {
648 	if (page->mem_cgroup)
649 		mod_memcg_state(page->mem_cgroup, idx, val);
650 }
651 
652 static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
653 					      enum node_stat_item idx)
654 {
655 	struct mem_cgroup_per_node *pn;
656 	long x;
657 
658 	if (mem_cgroup_disabled())
659 		return node_page_state(lruvec_pgdat(lruvec), idx);
660 
661 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
662 	x = atomic_long_read(&pn->lruvec_stat[idx]);
663 #ifdef CONFIG_SMP
664 	if (x < 0)
665 		x = 0;
666 #endif
667 	return x;
668 }
669 
670 static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
671 						    enum node_stat_item idx)
672 {
673 	struct mem_cgroup_per_node *pn;
674 	long x = 0;
675 	int cpu;
676 
677 	if (mem_cgroup_disabled())
678 		return node_page_state(lruvec_pgdat(lruvec), idx);
679 
680 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
681 	for_each_possible_cpu(cpu)
682 		x += per_cpu(pn->lruvec_stat_local->count[idx], cpu);
683 #ifdef CONFIG_SMP
684 	if (x < 0)
685 		x = 0;
686 #endif
687 	return x;
688 }
689 
690 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
691 			int val);
692 void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val);
693 
694 static inline void mod_lruvec_state(struct lruvec *lruvec,
695 				    enum node_stat_item idx, int val)
696 {
697 	unsigned long flags;
698 
699 	local_irq_save(flags);
700 	__mod_lruvec_state(lruvec, idx, val);
701 	local_irq_restore(flags);
702 }
703 
704 static inline void __mod_lruvec_page_state(struct page *page,
705 					   enum node_stat_item idx, int val)
706 {
707 	pg_data_t *pgdat = page_pgdat(page);
708 	struct lruvec *lruvec;
709 
710 	/* Untracked pages have no memcg, no lruvec. Update only the node */
711 	if (!page->mem_cgroup) {
712 		__mod_node_page_state(pgdat, idx, val);
713 		return;
714 	}
715 
716 	lruvec = mem_cgroup_lruvec(pgdat, page->mem_cgroup);
717 	__mod_lruvec_state(lruvec, idx, val);
718 }
719 
720 static inline void mod_lruvec_page_state(struct page *page,
721 					 enum node_stat_item idx, int val)
722 {
723 	unsigned long flags;
724 
725 	local_irq_save(flags);
726 	__mod_lruvec_page_state(page, idx, val);
727 	local_irq_restore(flags);
728 }
729 
730 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
731 						gfp_t gfp_mask,
732 						unsigned long *total_scanned);
733 
734 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
735 			  unsigned long count);
736 
737 static inline void count_memcg_events(struct mem_cgroup *memcg,
738 				      enum vm_event_item idx,
739 				      unsigned long count)
740 {
741 	unsigned long flags;
742 
743 	local_irq_save(flags);
744 	__count_memcg_events(memcg, idx, count);
745 	local_irq_restore(flags);
746 }
747 
748 static inline void count_memcg_page_event(struct page *page,
749 					  enum vm_event_item idx)
750 {
751 	if (page->mem_cgroup)
752 		count_memcg_events(page->mem_cgroup, idx, 1);
753 }
754 
755 static inline void count_memcg_event_mm(struct mm_struct *mm,
756 					enum vm_event_item idx)
757 {
758 	struct mem_cgroup *memcg;
759 
760 	if (mem_cgroup_disabled())
761 		return;
762 
763 	rcu_read_lock();
764 	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
765 	if (likely(memcg))
766 		count_memcg_events(memcg, idx, 1);
767 	rcu_read_unlock();
768 }
769 
770 static inline void memcg_memory_event(struct mem_cgroup *memcg,
771 				      enum memcg_memory_event event)
772 {
773 	atomic_long_inc(&memcg->memory_events_local[event]);
774 	cgroup_file_notify(&memcg->events_local_file);
775 
776 	do {
777 		atomic_long_inc(&memcg->memory_events[event]);
778 		cgroup_file_notify(&memcg->events_file);
779 
780 		if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
781 			break;
782 	} while ((memcg = parent_mem_cgroup(memcg)) &&
783 		 !mem_cgroup_is_root(memcg));
784 }
785 
786 static inline void memcg_memory_event_mm(struct mm_struct *mm,
787 					 enum memcg_memory_event event)
788 {
789 	struct mem_cgroup *memcg;
790 
791 	if (mem_cgroup_disabled())
792 		return;
793 
794 	rcu_read_lock();
795 	memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
796 	if (likely(memcg))
797 		memcg_memory_event(memcg, event);
798 	rcu_read_unlock();
799 }
800 
801 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
802 void mem_cgroup_split_huge_fixup(struct page *head);
803 #endif
804 
805 #else /* CONFIG_MEMCG */
806 
807 #define MEM_CGROUP_ID_SHIFT	0
808 #define MEM_CGROUP_ID_MAX	0
809 
810 struct mem_cgroup;
811 
812 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
813 {
814 	return true;
815 }
816 
817 static inline bool mem_cgroup_disabled(void)
818 {
819 	return true;
820 }
821 
822 static inline void memcg_memory_event(struct mem_cgroup *memcg,
823 				      enum memcg_memory_event event)
824 {
825 }
826 
827 static inline void memcg_memory_event_mm(struct mm_struct *mm,
828 					 enum memcg_memory_event event)
829 {
830 }
831 
832 static inline enum mem_cgroup_protection mem_cgroup_protected(
833 	struct mem_cgroup *root, struct mem_cgroup *memcg)
834 {
835 	return MEMCG_PROT_NONE;
836 }
837 
838 static inline int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
839 					gfp_t gfp_mask,
840 					struct mem_cgroup **memcgp,
841 					bool compound)
842 {
843 	*memcgp = NULL;
844 	return 0;
845 }
846 
847 static inline int mem_cgroup_try_charge_delay(struct page *page,
848 					      struct mm_struct *mm,
849 					      gfp_t gfp_mask,
850 					      struct mem_cgroup **memcgp,
851 					      bool compound)
852 {
853 	*memcgp = NULL;
854 	return 0;
855 }
856 
857 static inline void mem_cgroup_commit_charge(struct page *page,
858 					    struct mem_cgroup *memcg,
859 					    bool lrucare, bool compound)
860 {
861 }
862 
863 static inline void mem_cgroup_cancel_charge(struct page *page,
864 					    struct mem_cgroup *memcg,
865 					    bool compound)
866 {
867 }
868 
869 static inline void mem_cgroup_uncharge(struct page *page)
870 {
871 }
872 
873 static inline void mem_cgroup_uncharge_list(struct list_head *page_list)
874 {
875 }
876 
877 static inline void mem_cgroup_migrate(struct page *old, struct page *new)
878 {
879 }
880 
881 static inline struct lruvec *mem_cgroup_lruvec(struct pglist_data *pgdat,
882 				struct mem_cgroup *memcg)
883 {
884 	return node_lruvec(pgdat);
885 }
886 
887 static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
888 						    struct pglist_data *pgdat)
889 {
890 	return &pgdat->lruvec;
891 }
892 
893 static inline bool mm_match_cgroup(struct mm_struct *mm,
894 		struct mem_cgroup *memcg)
895 {
896 	return true;
897 }
898 
899 static inline struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
900 {
901 	return NULL;
902 }
903 
904 static inline struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
905 {
906 	return NULL;
907 }
908 
909 static inline void mem_cgroup_put(struct mem_cgroup *memcg)
910 {
911 }
912 
913 static inline struct mem_cgroup *
914 mem_cgroup_iter(struct mem_cgroup *root,
915 		struct mem_cgroup *prev,
916 		struct mem_cgroup_reclaim_cookie *reclaim)
917 {
918 	return NULL;
919 }
920 
921 static inline void mem_cgroup_iter_break(struct mem_cgroup *root,
922 					 struct mem_cgroup *prev)
923 {
924 }
925 
926 static inline int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
927 		int (*fn)(struct task_struct *, void *), void *arg)
928 {
929 	return 0;
930 }
931 
932 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
933 {
934 	return 0;
935 }
936 
937 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
938 {
939 	WARN_ON_ONCE(id);
940 	/* XXX: This should always return root_mem_cgroup */
941 	return NULL;
942 }
943 
944 static inline struct mem_cgroup *mem_cgroup_from_seq(struct seq_file *m)
945 {
946 	return NULL;
947 }
948 
949 static inline struct mem_cgroup *lruvec_memcg(struct lruvec *lruvec)
950 {
951 	return NULL;
952 }
953 
954 static inline bool mem_cgroup_online(struct mem_cgroup *memcg)
955 {
956 	return true;
957 }
958 
959 static inline
960 unsigned long mem_cgroup_get_zone_lru_size(struct lruvec *lruvec,
961 		enum lru_list lru, int zone_idx)
962 {
963 	return 0;
964 }
965 
966 static inline unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
967 {
968 	return 0;
969 }
970 
971 static inline void
972 mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
973 {
974 }
975 
976 static inline void
977 mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
978 {
979 }
980 
981 static inline struct mem_cgroup *lock_page_memcg(struct page *page)
982 {
983 	return NULL;
984 }
985 
986 static inline void __unlock_page_memcg(struct mem_cgroup *memcg)
987 {
988 }
989 
990 static inline void unlock_page_memcg(struct page *page)
991 {
992 }
993 
994 static inline void mem_cgroup_handle_over_high(void)
995 {
996 }
997 
998 static inline void mem_cgroup_enter_user_fault(void)
999 {
1000 }
1001 
1002 static inline void mem_cgroup_exit_user_fault(void)
1003 {
1004 }
1005 
1006 static inline bool task_in_memcg_oom(struct task_struct *p)
1007 {
1008 	return false;
1009 }
1010 
1011 static inline bool mem_cgroup_oom_synchronize(bool wait)
1012 {
1013 	return false;
1014 }
1015 
1016 static inline struct mem_cgroup *mem_cgroup_get_oom_group(
1017 	struct task_struct *victim, struct mem_cgroup *oom_domain)
1018 {
1019 	return NULL;
1020 }
1021 
1022 static inline void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
1023 {
1024 }
1025 
1026 static inline unsigned long memcg_page_state(struct mem_cgroup *memcg, int idx)
1027 {
1028 	return 0;
1029 }
1030 
1031 static inline unsigned long memcg_page_state_local(struct mem_cgroup *memcg,
1032 						   int idx)
1033 {
1034 	return 0;
1035 }
1036 
1037 static inline void __mod_memcg_state(struct mem_cgroup *memcg,
1038 				     int idx,
1039 				     int nr)
1040 {
1041 }
1042 
1043 static inline void mod_memcg_state(struct mem_cgroup *memcg,
1044 				   int idx,
1045 				   int nr)
1046 {
1047 }
1048 
1049 static inline void __mod_memcg_page_state(struct page *page,
1050 					  int idx,
1051 					  int nr)
1052 {
1053 }
1054 
1055 static inline void mod_memcg_page_state(struct page *page,
1056 					int idx,
1057 					int nr)
1058 {
1059 }
1060 
1061 static inline unsigned long lruvec_page_state(struct lruvec *lruvec,
1062 					      enum node_stat_item idx)
1063 {
1064 	return node_page_state(lruvec_pgdat(lruvec), idx);
1065 }
1066 
1067 static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
1068 						    enum node_stat_item idx)
1069 {
1070 	return node_page_state(lruvec_pgdat(lruvec), idx);
1071 }
1072 
1073 static inline void __mod_lruvec_state(struct lruvec *lruvec,
1074 				      enum node_stat_item idx, int val)
1075 {
1076 	__mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
1077 }
1078 
1079 static inline void mod_lruvec_state(struct lruvec *lruvec,
1080 				    enum node_stat_item idx, int val)
1081 {
1082 	mod_node_page_state(lruvec_pgdat(lruvec), idx, val);
1083 }
1084 
1085 static inline void __mod_lruvec_page_state(struct page *page,
1086 					   enum node_stat_item idx, int val)
1087 {
1088 	__mod_node_page_state(page_pgdat(page), idx, val);
1089 }
1090 
1091 static inline void mod_lruvec_page_state(struct page *page,
1092 					 enum node_stat_item idx, int val)
1093 {
1094 	mod_node_page_state(page_pgdat(page), idx, val);
1095 }
1096 
1097 static inline void __mod_lruvec_slab_state(void *p, enum node_stat_item idx,
1098 					   int val)
1099 {
1100 	struct page *page = virt_to_head_page(p);
1101 
1102 	__mod_node_page_state(page_pgdat(page), idx, val);
1103 }
1104 
1105 static inline
1106 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
1107 					    gfp_t gfp_mask,
1108 					    unsigned long *total_scanned)
1109 {
1110 	return 0;
1111 }
1112 
1113 static inline void mem_cgroup_split_huge_fixup(struct page *head)
1114 {
1115 }
1116 
1117 static inline void count_memcg_events(struct mem_cgroup *memcg,
1118 				      enum vm_event_item idx,
1119 				      unsigned long count)
1120 {
1121 }
1122 
1123 static inline void __count_memcg_events(struct mem_cgroup *memcg,
1124 					enum vm_event_item idx,
1125 					unsigned long count)
1126 {
1127 }
1128 
1129 static inline void count_memcg_page_event(struct page *page,
1130 					  int idx)
1131 {
1132 }
1133 
1134 static inline
1135 void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
1136 {
1137 }
1138 #endif /* CONFIG_MEMCG */
1139 
1140 /* idx can be of type enum memcg_stat_item or node_stat_item */
1141 static inline void __inc_memcg_state(struct mem_cgroup *memcg,
1142 				     int idx)
1143 {
1144 	__mod_memcg_state(memcg, idx, 1);
1145 }
1146 
1147 /* idx can be of type enum memcg_stat_item or node_stat_item */
1148 static inline void __dec_memcg_state(struct mem_cgroup *memcg,
1149 				     int idx)
1150 {
1151 	__mod_memcg_state(memcg, idx, -1);
1152 }
1153 
1154 /* idx can be of type enum memcg_stat_item or node_stat_item */
1155 static inline void __inc_memcg_page_state(struct page *page,
1156 					  int idx)
1157 {
1158 	__mod_memcg_page_state(page, idx, 1);
1159 }
1160 
1161 /* idx can be of type enum memcg_stat_item or node_stat_item */
1162 static inline void __dec_memcg_page_state(struct page *page,
1163 					  int idx)
1164 {
1165 	__mod_memcg_page_state(page, idx, -1);
1166 }
1167 
1168 static inline void __inc_lruvec_state(struct lruvec *lruvec,
1169 				      enum node_stat_item idx)
1170 {
1171 	__mod_lruvec_state(lruvec, idx, 1);
1172 }
1173 
1174 static inline void __dec_lruvec_state(struct lruvec *lruvec,
1175 				      enum node_stat_item idx)
1176 {
1177 	__mod_lruvec_state(lruvec, idx, -1);
1178 }
1179 
1180 static inline void __inc_lruvec_page_state(struct page *page,
1181 					   enum node_stat_item idx)
1182 {
1183 	__mod_lruvec_page_state(page, idx, 1);
1184 }
1185 
1186 static inline void __dec_lruvec_page_state(struct page *page,
1187 					   enum node_stat_item idx)
1188 {
1189 	__mod_lruvec_page_state(page, idx, -1);
1190 }
1191 
1192 static inline void __inc_lruvec_slab_state(void *p, enum node_stat_item idx)
1193 {
1194 	__mod_lruvec_slab_state(p, idx, 1);
1195 }
1196 
1197 static inline void __dec_lruvec_slab_state(void *p, enum node_stat_item idx)
1198 {
1199 	__mod_lruvec_slab_state(p, idx, -1);
1200 }
1201 
1202 /* idx can be of type enum memcg_stat_item or node_stat_item */
1203 static inline void inc_memcg_state(struct mem_cgroup *memcg,
1204 				   int idx)
1205 {
1206 	mod_memcg_state(memcg, idx, 1);
1207 }
1208 
1209 /* idx can be of type enum memcg_stat_item or node_stat_item */
1210 static inline void dec_memcg_state(struct mem_cgroup *memcg,
1211 				   int idx)
1212 {
1213 	mod_memcg_state(memcg, idx, -1);
1214 }
1215 
1216 /* idx can be of type enum memcg_stat_item or node_stat_item */
1217 static inline void inc_memcg_page_state(struct page *page,
1218 					int idx)
1219 {
1220 	mod_memcg_page_state(page, idx, 1);
1221 }
1222 
1223 /* idx can be of type enum memcg_stat_item or node_stat_item */
1224 static inline void dec_memcg_page_state(struct page *page,
1225 					int idx)
1226 {
1227 	mod_memcg_page_state(page, idx, -1);
1228 }
1229 
1230 static inline void inc_lruvec_state(struct lruvec *lruvec,
1231 				    enum node_stat_item idx)
1232 {
1233 	mod_lruvec_state(lruvec, idx, 1);
1234 }
1235 
1236 static inline void dec_lruvec_state(struct lruvec *lruvec,
1237 				    enum node_stat_item idx)
1238 {
1239 	mod_lruvec_state(lruvec, idx, -1);
1240 }
1241 
1242 static inline void inc_lruvec_page_state(struct page *page,
1243 					 enum node_stat_item idx)
1244 {
1245 	mod_lruvec_page_state(page, idx, 1);
1246 }
1247 
1248 static inline void dec_lruvec_page_state(struct page *page,
1249 					 enum node_stat_item idx)
1250 {
1251 	mod_lruvec_page_state(page, idx, -1);
1252 }
1253 
1254 #ifdef CONFIG_CGROUP_WRITEBACK
1255 
1256 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb);
1257 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
1258 			 unsigned long *pheadroom, unsigned long *pdirty,
1259 			 unsigned long *pwriteback);
1260 
1261 void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
1262 					     struct bdi_writeback *wb);
1263 
1264 static inline void mem_cgroup_track_foreign_dirty(struct page *page,
1265 						  struct bdi_writeback *wb)
1266 {
1267 	if (unlikely(&page->mem_cgroup->css != wb->memcg_css))
1268 		mem_cgroup_track_foreign_dirty_slowpath(page, wb);
1269 }
1270 
1271 void mem_cgroup_flush_foreign(struct bdi_writeback *wb);
1272 
1273 #else	/* CONFIG_CGROUP_WRITEBACK */
1274 
1275 static inline struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
1276 {
1277 	return NULL;
1278 }
1279 
1280 static inline void mem_cgroup_wb_stats(struct bdi_writeback *wb,
1281 				       unsigned long *pfilepages,
1282 				       unsigned long *pheadroom,
1283 				       unsigned long *pdirty,
1284 				       unsigned long *pwriteback)
1285 {
1286 }
1287 
1288 static inline void mem_cgroup_track_foreign_dirty(struct page *page,
1289 						  struct bdi_writeback *wb)
1290 {
1291 }
1292 
1293 static inline void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
1294 {
1295 }
1296 
1297 #endif	/* CONFIG_CGROUP_WRITEBACK */
1298 
1299 struct sock;
1300 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
1301 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages);
1302 #ifdef CONFIG_MEMCG
1303 extern struct static_key_false memcg_sockets_enabled_key;
1304 #define mem_cgroup_sockets_enabled static_branch_unlikely(&memcg_sockets_enabled_key)
1305 void mem_cgroup_sk_alloc(struct sock *sk);
1306 void mem_cgroup_sk_free(struct sock *sk);
1307 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
1308 {
1309 	if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_pressure)
1310 		return true;
1311 	do {
1312 		if (time_before(jiffies, memcg->socket_pressure))
1313 			return true;
1314 	} while ((memcg = parent_mem_cgroup(memcg)));
1315 	return false;
1316 }
1317 
1318 extern int memcg_expand_shrinker_maps(int new_id);
1319 
1320 extern void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
1321 				   int nid, int shrinker_id);
1322 #else
1323 #define mem_cgroup_sockets_enabled 0
1324 static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
1325 static inline void mem_cgroup_sk_free(struct sock *sk) { };
1326 static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
1327 {
1328 	return false;
1329 }
1330 
1331 static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
1332 					  int nid, int shrinker_id)
1333 {
1334 }
1335 #endif
1336 
1337 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep);
1338 void memcg_kmem_put_cache(struct kmem_cache *cachep);
1339 
1340 #ifdef CONFIG_MEMCG_KMEM
1341 int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order);
1342 void __memcg_kmem_uncharge(struct page *page, int order);
1343 int __memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
1344 			      struct mem_cgroup *memcg);
1345 void __memcg_kmem_uncharge_memcg(struct mem_cgroup *memcg,
1346 				 unsigned int nr_pages);
1347 
1348 extern struct static_key_false memcg_kmem_enabled_key;
1349 extern struct workqueue_struct *memcg_kmem_cache_wq;
1350 
1351 extern int memcg_nr_cache_ids;
1352 void memcg_get_cache_ids(void);
1353 void memcg_put_cache_ids(void);
1354 
1355 /*
1356  * Helper macro to loop through all memcg-specific caches. Callers must still
1357  * check if the cache is valid (it is either valid or NULL).
1358  * the slab_mutex must be held when looping through those caches
1359  */
1360 #define for_each_memcg_cache_index(_idx)	\
1361 	for ((_idx) = 0; (_idx) < memcg_nr_cache_ids; (_idx)++)
1362 
1363 static inline bool memcg_kmem_enabled(void)
1364 {
1365 	return static_branch_unlikely(&memcg_kmem_enabled_key);
1366 }
1367 
1368 static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
1369 {
1370 	if (memcg_kmem_enabled())
1371 		return __memcg_kmem_charge(page, gfp, order);
1372 	return 0;
1373 }
1374 
1375 static inline void memcg_kmem_uncharge(struct page *page, int order)
1376 {
1377 	if (memcg_kmem_enabled())
1378 		__memcg_kmem_uncharge(page, order);
1379 }
1380 
1381 static inline int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp,
1382 					  int order, struct mem_cgroup *memcg)
1383 {
1384 	if (memcg_kmem_enabled())
1385 		return __memcg_kmem_charge_memcg(page, gfp, order, memcg);
1386 	return 0;
1387 }
1388 
1389 static inline void memcg_kmem_uncharge_memcg(struct page *page, int order,
1390 					     struct mem_cgroup *memcg)
1391 {
1392 	if (memcg_kmem_enabled())
1393 		__memcg_kmem_uncharge_memcg(memcg, 1 << order);
1394 }
1395 
1396 /*
1397  * helper for accessing a memcg's index. It will be used as an index in the
1398  * child cache array in kmem_cache, and also to derive its name. This function
1399  * will return -1 when this is not a kmem-limited memcg.
1400  */
1401 static inline int memcg_cache_id(struct mem_cgroup *memcg)
1402 {
1403 	return memcg ? memcg->kmemcg_id : -1;
1404 }
1405 
1406 #else
1407 
1408 static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
1409 {
1410 	return 0;
1411 }
1412 
1413 static inline void memcg_kmem_uncharge(struct page *page, int order)
1414 {
1415 }
1416 
1417 static inline int __memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
1418 {
1419 	return 0;
1420 }
1421 
1422 static inline void __memcg_kmem_uncharge(struct page *page, int order)
1423 {
1424 }
1425 
1426 #define for_each_memcg_cache_index(_idx)	\
1427 	for (; NULL; )
1428 
1429 static inline bool memcg_kmem_enabled(void)
1430 {
1431 	return false;
1432 }
1433 
1434 static inline int memcg_cache_id(struct mem_cgroup *memcg)
1435 {
1436 	return -1;
1437 }
1438 
1439 static inline void memcg_get_cache_ids(void)
1440 {
1441 }
1442 
1443 static inline void memcg_put_cache_ids(void)
1444 {
1445 }
1446 
1447 #endif /* CONFIG_MEMCG_KMEM */
1448 
1449 #endif /* _LINUX_MEMCONTROL_H */
1450