1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
28 #include <linux/res_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
32 #include <linux/hugetlb.h>
33 #include <linux/pagemap.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/slab.h>
43 #include <linux/swap.h>
44 #include <linux/swapops.h>
45 #include <linux/spinlock.h>
46 #include <linux/eventfd.h>
47 #include <linux/sort.h>
49 #include <linux/seq_file.h>
50 #include <linux/vmalloc.h>
51 #include <linux/vmpressure.h>
52 #include <linux/mm_inline.h>
53 #include <linux/page_cgroup.h>
54 #include <linux/cpu.h>
55 #include <linux/oom.h>
59 #include <net/tcp_memcontrol.h>
61 #include <asm/uaccess.h>
63 #include <trace/events/vmscan.h>
65 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
66 EXPORT_SYMBOL(mem_cgroup_subsys);
68 #define MEM_CGROUP_RECLAIM_RETRIES 5
69 static struct mem_cgroup *root_mem_cgroup __read_mostly;
71 #ifdef CONFIG_MEMCG_SWAP
72 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
73 int do_swap_account __read_mostly;
75 /* for remember boot option*/
76 #ifdef CONFIG_MEMCG_SWAP_ENABLED
77 static int really_do_swap_account __initdata = 1;
79 static int really_do_swap_account __initdata = 0;
83 #define do_swap_account 0
88 * Statistics for memory cgroup.
90 enum mem_cgroup_stat_index {
92 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
94 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
95 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
96 MEM_CGROUP_STAT_RSS_HUGE, /* # of pages charged as anon huge */
97 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
98 MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
99 MEM_CGROUP_STAT_NSTATS,
102 static const char * const mem_cgroup_stat_names[] = {
110 enum mem_cgroup_events_index {
111 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
112 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
113 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
114 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
115 MEM_CGROUP_EVENTS_NSTATS,
118 static const char * const mem_cgroup_events_names[] = {
125 static const char * const mem_cgroup_lru_names[] = {
134 * Per memcg event counter is incremented at every pagein/pageout. With THP,
135 * it will be incremated by the number of pages. This counter is used for
136 * for trigger some periodic events. This is straightforward and better
137 * than using jiffies etc. to handle periodic memcg event.
139 enum mem_cgroup_events_target {
140 MEM_CGROUP_TARGET_THRESH,
141 MEM_CGROUP_TARGET_NUMAINFO,
144 #define THRESHOLDS_EVENTS_TARGET 128
145 #define SOFTLIMIT_EVENTS_TARGET 1024
146 #define NUMAINFO_EVENTS_TARGET 1024
148 struct mem_cgroup_stat_cpu {
149 long count[MEM_CGROUP_STAT_NSTATS];
150 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
151 unsigned long nr_page_events;
152 unsigned long targets[MEM_CGROUP_NTARGETS];
155 struct mem_cgroup_reclaim_iter {
157 * last scanned hierarchy member. Valid only if last_dead_count
158 * matches memcg->dead_count of the hierarchy root group.
160 struct mem_cgroup *last_visited;
161 unsigned long last_dead_count;
163 /* scan generation, increased every round-trip */
164 unsigned int generation;
168 * per-zone information in memory controller.
170 struct mem_cgroup_per_zone {
171 struct lruvec lruvec;
172 unsigned long lru_size[NR_LRU_LISTS];
174 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
176 struct mem_cgroup *memcg; /* Back pointer, we cannot */
177 /* use container_of */
180 struct mem_cgroup_per_node {
181 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
184 struct mem_cgroup_threshold {
185 struct eventfd_ctx *eventfd;
190 struct mem_cgroup_threshold_ary {
191 /* An array index points to threshold just below or equal to usage. */
192 int current_threshold;
193 /* Size of entries[] */
195 /* Array of thresholds */
196 struct mem_cgroup_threshold entries[0];
199 struct mem_cgroup_thresholds {
200 /* Primary thresholds array */
201 struct mem_cgroup_threshold_ary *primary;
203 * Spare threshold array.
204 * This is needed to make mem_cgroup_unregister_event() "never fail".
205 * It must be able to store at least primary->size - 1 entries.
207 struct mem_cgroup_threshold_ary *spare;
211 struct mem_cgroup_eventfd_list {
212 struct list_head list;
213 struct eventfd_ctx *eventfd;
216 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
217 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
220 * The memory controller data structure. The memory controller controls both
221 * page cache and RSS per cgroup. We would eventually like to provide
222 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
223 * to help the administrator determine what knobs to tune.
225 * TODO: Add a water mark for the memory controller. Reclaim will begin when
226 * we hit the water mark. May be even add a low water mark, such that
227 * no reclaim occurs from a cgroup at it's low water mark, this is
228 * a feature that will be implemented much later in the future.
231 struct cgroup_subsys_state css;
233 * the counter to account for memory usage
235 struct res_counter res;
237 /* vmpressure notifications */
238 struct vmpressure vmpressure;
241 * the counter to account for mem+swap usage.
243 struct res_counter memsw;
246 * the counter to account for kernel memory usage.
248 struct res_counter kmem;
250 * Should the accounting and control be hierarchical, per subtree?
253 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
259 /* OOM-Killer disable */
260 int oom_kill_disable;
262 /* set when res.limit == memsw.limit */
263 bool memsw_is_minimum;
265 /* protect arrays of thresholds */
266 struct mutex thresholds_lock;
268 /* thresholds for memory usage. RCU-protected */
269 struct mem_cgroup_thresholds thresholds;
271 /* thresholds for mem+swap usage. RCU-protected */
272 struct mem_cgroup_thresholds memsw_thresholds;
274 /* For oom notifier event fd */
275 struct list_head oom_notify;
278 * Should we move charges of a task when a task is moved into this
279 * mem_cgroup ? And what type of charges should we move ?
281 unsigned long move_charge_at_immigrate;
283 * set > 0 if pages under this cgroup are moving to other cgroup.
285 atomic_t moving_account;
286 /* taken only while moving_account > 0 */
287 spinlock_t move_lock;
291 struct mem_cgroup_stat_cpu __percpu *stat;
293 * used when a cpu is offlined or other synchronizations
294 * See mem_cgroup_read_stat().
296 struct mem_cgroup_stat_cpu nocpu_base;
297 spinlock_t pcp_counter_lock;
300 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
301 struct tcp_memcontrol tcp_mem;
303 #if defined(CONFIG_MEMCG_KMEM)
304 /* analogous to slab_common's slab_caches list. per-memcg */
305 struct list_head memcg_slab_caches;
306 /* Not a spinlock, we can take a lot of time walking the list */
307 struct mutex slab_caches_mutex;
308 /* Index in the kmem_cache->memcg_params->memcg_caches array */
312 int last_scanned_node;
314 nodemask_t scan_nodes;
315 atomic_t numainfo_events;
316 atomic_t numainfo_updating;
319 struct mem_cgroup_per_node *nodeinfo[0];
320 /* WARNING: nodeinfo must be the last member here */
323 static size_t memcg_size(void)
325 return sizeof(struct mem_cgroup) +
326 nr_node_ids * sizeof(struct mem_cgroup_per_node);
329 /* internal only representation about the status of kmem accounting. */
331 KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */
332 KMEM_ACCOUNTED_ACTIVATED, /* static key enabled. */
333 KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
336 /* We account when limit is on, but only after call sites are patched */
337 #define KMEM_ACCOUNTED_MASK \
338 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
340 #ifdef CONFIG_MEMCG_KMEM
341 static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
343 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
346 static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
348 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
351 static void memcg_kmem_set_activated(struct mem_cgroup *memcg)
353 set_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags);
356 static void memcg_kmem_clear_activated(struct mem_cgroup *memcg)
358 clear_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags);
361 static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
364 * Our caller must use css_get() first, because memcg_uncharge_kmem()
365 * will call css_put() if it sees the memcg is dead.
368 if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
369 set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
372 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg)
374 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD,
375 &memcg->kmem_account_flags);
379 /* Stuffs for move charges at task migration. */
381 * Types of charges to be moved. "move_charge_at_immitgrate" and
382 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
385 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
386 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
390 /* "mc" and its members are protected by cgroup_mutex */
391 static struct move_charge_struct {
392 spinlock_t lock; /* for from, to */
393 struct mem_cgroup *from;
394 struct mem_cgroup *to;
395 unsigned long immigrate_flags;
396 unsigned long precharge;
397 unsigned long moved_charge;
398 unsigned long moved_swap;
399 struct task_struct *moving_task; /* a task moving charges */
400 wait_queue_head_t waitq; /* a waitq for other context */
402 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
403 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
406 static bool move_anon(void)
408 return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
411 static bool move_file(void)
413 return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
417 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
418 * limit reclaim to prevent infinite loops, if they ever occur.
420 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
423 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
424 MEM_CGROUP_CHARGE_TYPE_ANON,
425 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
426 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
430 /* for encoding cft->private value on file */
438 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
439 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
440 #define MEMFILE_ATTR(val) ((val) & 0xffff)
441 /* Used for OOM nofiier */
442 #define OOM_CONTROL (0)
445 * Reclaim flags for mem_cgroup_hierarchical_reclaim
447 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
448 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
449 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
450 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
453 * The memcg_create_mutex will be held whenever a new cgroup is created.
454 * As a consequence, any change that needs to protect against new child cgroups
455 * appearing has to hold it as well.
457 static DEFINE_MUTEX(memcg_create_mutex);
459 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
461 return s ? container_of(s, struct mem_cgroup, css) : NULL;
464 /* Some nice accessors for the vmpressure. */
465 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
468 memcg = root_mem_cgroup;
469 return &memcg->vmpressure;
472 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
474 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
477 struct vmpressure *css_to_vmpressure(struct cgroup_subsys_state *css)
479 return &mem_cgroup_from_css(css)->vmpressure;
482 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
484 return (memcg == root_mem_cgroup);
487 /* Writing them here to avoid exposing memcg's inner layout */
488 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
490 void sock_update_memcg(struct sock *sk)
492 if (mem_cgroup_sockets_enabled) {
493 struct mem_cgroup *memcg;
494 struct cg_proto *cg_proto;
496 BUG_ON(!sk->sk_prot->proto_cgroup);
498 /* Socket cloning can throw us here with sk_cgrp already
499 * filled. It won't however, necessarily happen from
500 * process context. So the test for root memcg given
501 * the current task's memcg won't help us in this case.
503 * Respecting the original socket's memcg is a better
504 * decision in this case.
507 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
508 css_get(&sk->sk_cgrp->memcg->css);
513 memcg = mem_cgroup_from_task(current);
514 cg_proto = sk->sk_prot->proto_cgroup(memcg);
515 if (!mem_cgroup_is_root(memcg) &&
516 memcg_proto_active(cg_proto) && css_tryget(&memcg->css)) {
517 sk->sk_cgrp = cg_proto;
522 EXPORT_SYMBOL(sock_update_memcg);
524 void sock_release_memcg(struct sock *sk)
526 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
527 struct mem_cgroup *memcg;
528 WARN_ON(!sk->sk_cgrp->memcg);
529 memcg = sk->sk_cgrp->memcg;
530 css_put(&sk->sk_cgrp->memcg->css);
534 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
536 if (!memcg || mem_cgroup_is_root(memcg))
539 return &memcg->tcp_mem.cg_proto;
541 EXPORT_SYMBOL(tcp_proto_cgroup);
543 static void disarm_sock_keys(struct mem_cgroup *memcg)
545 if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto))
547 static_key_slow_dec(&memcg_socket_limit_enabled);
550 static void disarm_sock_keys(struct mem_cgroup *memcg)
555 #ifdef CONFIG_MEMCG_KMEM
557 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
558 * There are two main reasons for not using the css_id for this:
559 * 1) this works better in sparse environments, where we have a lot of memcgs,
560 * but only a few kmem-limited. Or also, if we have, for instance, 200
561 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
562 * 200 entry array for that.
564 * 2) In order not to violate the cgroup API, we would like to do all memory
565 * allocation in ->create(). At that point, we haven't yet allocated the
566 * css_id. Having a separate index prevents us from messing with the cgroup
569 * The current size of the caches array is stored in
570 * memcg_limited_groups_array_size. It will double each time we have to
573 static DEFINE_IDA(kmem_limited_groups);
574 int memcg_limited_groups_array_size;
577 * MIN_SIZE is different than 1, because we would like to avoid going through
578 * the alloc/free process all the time. In a small machine, 4 kmem-limited
579 * cgroups is a reasonable guess. In the future, it could be a parameter or
580 * tunable, but that is strictly not necessary.
582 * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get
583 * this constant directly from cgroup, but it is understandable that this is
584 * better kept as an internal representation in cgroup.c. In any case, the
585 * css_id space is not getting any smaller, and we don't have to necessarily
586 * increase ours as well if it increases.
588 #define MEMCG_CACHES_MIN_SIZE 4
589 #define MEMCG_CACHES_MAX_SIZE 65535
592 * A lot of the calls to the cache allocation functions are expected to be
593 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
594 * conditional to this static branch, we'll have to allow modules that does
595 * kmem_cache_alloc and the such to see this symbol as well
597 struct static_key memcg_kmem_enabled_key;
598 EXPORT_SYMBOL(memcg_kmem_enabled_key);
600 static void disarm_kmem_keys(struct mem_cgroup *memcg)
602 if (memcg_kmem_is_active(memcg)) {
603 static_key_slow_dec(&memcg_kmem_enabled_key);
604 ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
607 * This check can't live in kmem destruction function,
608 * since the charges will outlive the cgroup
610 WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
613 static void disarm_kmem_keys(struct mem_cgroup *memcg)
616 #endif /* CONFIG_MEMCG_KMEM */
618 static void disarm_static_keys(struct mem_cgroup *memcg)
620 disarm_sock_keys(memcg);
621 disarm_kmem_keys(memcg);
624 static void drain_all_stock_async(struct mem_cgroup *memcg);
626 static struct mem_cgroup_per_zone *
627 mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
629 VM_BUG_ON((unsigned)nid >= nr_node_ids);
630 return &memcg->nodeinfo[nid]->zoneinfo[zid];
633 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
638 static struct mem_cgroup_per_zone *
639 page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
641 int nid = page_to_nid(page);
642 int zid = page_zonenum(page);
644 return mem_cgroup_zoneinfo(memcg, nid, zid);
648 * Implementation Note: reading percpu statistics for memcg.
650 * Both of vmstat[] and percpu_counter has threshold and do periodic
651 * synchronization to implement "quick" read. There are trade-off between
652 * reading cost and precision of value. Then, we may have a chance to implement
653 * a periodic synchronizion of counter in memcg's counter.
655 * But this _read() function is used for user interface now. The user accounts
656 * memory usage by memory cgroup and he _always_ requires exact value because
657 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
658 * have to visit all online cpus and make sum. So, for now, unnecessary
659 * synchronization is not implemented. (just implemented for cpu hotplug)
661 * If there are kernel internal actions which can make use of some not-exact
662 * value, and reading all cpu value can be performance bottleneck in some
663 * common workload, threashold and synchonization as vmstat[] should be
666 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
667 enum mem_cgroup_stat_index idx)
673 for_each_online_cpu(cpu)
674 val += per_cpu(memcg->stat->count[idx], cpu);
675 #ifdef CONFIG_HOTPLUG_CPU
676 spin_lock(&memcg->pcp_counter_lock);
677 val += memcg->nocpu_base.count[idx];
678 spin_unlock(&memcg->pcp_counter_lock);
684 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
687 int val = (charge) ? 1 : -1;
688 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
691 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
692 enum mem_cgroup_events_index idx)
694 unsigned long val = 0;
697 for_each_online_cpu(cpu)
698 val += per_cpu(memcg->stat->events[idx], cpu);
699 #ifdef CONFIG_HOTPLUG_CPU
700 spin_lock(&memcg->pcp_counter_lock);
701 val += memcg->nocpu_base.events[idx];
702 spin_unlock(&memcg->pcp_counter_lock);
707 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
709 bool anon, int nr_pages)
714 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
715 * counted as CACHE even if it's on ANON LRU.
718 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
721 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
724 if (PageTransHuge(page))
725 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
728 /* pagein of a big page is an event. So, ignore page size */
730 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
732 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
733 nr_pages = -nr_pages; /* for event */
736 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
742 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
744 struct mem_cgroup_per_zone *mz;
746 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
747 return mz->lru_size[lru];
751 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
752 unsigned int lru_mask)
754 struct mem_cgroup_per_zone *mz;
756 unsigned long ret = 0;
758 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
761 if (BIT(lru) & lru_mask)
762 ret += mz->lru_size[lru];
768 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
769 int nid, unsigned int lru_mask)
774 for (zid = 0; zid < MAX_NR_ZONES; zid++)
775 total += mem_cgroup_zone_nr_lru_pages(memcg,
781 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
782 unsigned int lru_mask)
787 for_each_node_state(nid, N_MEMORY)
788 total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
792 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
793 enum mem_cgroup_events_target target)
795 unsigned long val, next;
797 val = __this_cpu_read(memcg->stat->nr_page_events);
798 next = __this_cpu_read(memcg->stat->targets[target]);
799 /* from time_after() in jiffies.h */
800 if ((long)next - (long)val < 0) {
802 case MEM_CGROUP_TARGET_THRESH:
803 next = val + THRESHOLDS_EVENTS_TARGET;
805 case MEM_CGROUP_TARGET_NUMAINFO:
806 next = val + NUMAINFO_EVENTS_TARGET;
811 __this_cpu_write(memcg->stat->targets[target], next);
818 * Check events in order.
821 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
824 /* threshold event is triggered in finer grain than soft limit */
825 if (unlikely(mem_cgroup_event_ratelimit(memcg,
826 MEM_CGROUP_TARGET_THRESH))) {
827 bool do_numainfo __maybe_unused;
830 do_numainfo = mem_cgroup_event_ratelimit(memcg,
831 MEM_CGROUP_TARGET_NUMAINFO);
835 mem_cgroup_threshold(memcg);
837 if (unlikely(do_numainfo))
838 atomic_inc(&memcg->numainfo_events);
844 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
847 * mm_update_next_owner() may clear mm->owner to NULL
848 * if it races with swapoff, page migration, etc.
849 * So this can be called with p == NULL.
854 return mem_cgroup_from_css(task_css(p, mem_cgroup_subsys_id));
857 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
859 struct mem_cgroup *memcg = NULL;
864 * Because we have no locks, mm->owner's may be being moved to other
865 * cgroup. We use css_tryget() here even if this looks
866 * pessimistic (rather than adding locks here).
870 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
871 if (unlikely(!memcg))
873 } while (!css_tryget(&memcg->css));
879 * Returns a next (in a pre-order walk) alive memcg (with elevated css
880 * ref. count) or NULL if the whole root's subtree has been visited.
882 * helper function to be used by mem_cgroup_iter
884 static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
885 struct mem_cgroup *last_visited)
887 struct cgroup_subsys_state *prev_css, *next_css;
889 prev_css = last_visited ? &last_visited->css : NULL;
891 next_css = css_next_descendant_pre(prev_css, &root->css);
894 * Even if we found a group we have to make sure it is
895 * alive. css && !memcg means that the groups should be
896 * skipped and we should continue the tree walk.
897 * last_visited css is safe to use because it is
898 * protected by css_get and the tree walk is rcu safe.
901 struct mem_cgroup *mem = mem_cgroup_from_css(next_css);
903 if (css_tryget(&mem->css))
914 static void mem_cgroup_iter_invalidate(struct mem_cgroup *root)
917 * When a group in the hierarchy below root is destroyed, the
918 * hierarchy iterator can no longer be trusted since it might
919 * have pointed to the destroyed group. Invalidate it.
921 atomic_inc(&root->dead_count);
924 static struct mem_cgroup *
925 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
926 struct mem_cgroup *root,
929 struct mem_cgroup *position = NULL;
931 * A cgroup destruction happens in two stages: offlining and
932 * release. They are separated by a RCU grace period.
934 * If the iterator is valid, we may still race with an
935 * offlining. The RCU lock ensures the object won't be
936 * released, tryget will fail if we lost the race.
938 *sequence = atomic_read(&root->dead_count);
939 if (iter->last_dead_count == *sequence) {
941 position = iter->last_visited;
942 if (position && !css_tryget(&position->css))
948 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
949 struct mem_cgroup *last_visited,
950 struct mem_cgroup *new_position,
954 css_put(&last_visited->css);
956 * We store the sequence count from the time @last_visited was
957 * loaded successfully instead of rereading it here so that we
958 * don't lose destruction events in between. We could have
959 * raced with the destruction of @new_position after all.
961 iter->last_visited = new_position;
963 iter->last_dead_count = sequence;
967 * mem_cgroup_iter - iterate over memory cgroup hierarchy
968 * @root: hierarchy root
969 * @prev: previously returned memcg, NULL on first invocation
970 * @reclaim: cookie for shared reclaim walks, NULL for full walks
972 * Returns references to children of the hierarchy below @root, or
973 * @root itself, or %NULL after a full round-trip.
975 * Caller must pass the return value in @prev on subsequent
976 * invocations for reference counting, or use mem_cgroup_iter_break()
977 * to cancel a hierarchy walk before the round-trip is complete.
979 * Reclaimers can specify a zone and a priority level in @reclaim to
980 * divide up the memcgs in the hierarchy among all concurrent
981 * reclaimers operating on the same zone and priority.
983 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
984 struct mem_cgroup *prev,
985 struct mem_cgroup_reclaim_cookie *reclaim)
987 struct mem_cgroup *memcg = NULL;
988 struct mem_cgroup *last_visited = NULL;
990 if (mem_cgroup_disabled())
994 root = root_mem_cgroup;
996 if (prev && !reclaim)
999 if (!root->use_hierarchy && root != root_mem_cgroup) {
1007 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1008 int uninitialized_var(seq);
1011 int nid = zone_to_nid(reclaim->zone);
1012 int zid = zone_idx(reclaim->zone);
1013 struct mem_cgroup_per_zone *mz;
1015 mz = mem_cgroup_zoneinfo(root, nid, zid);
1016 iter = &mz->reclaim_iter[reclaim->priority];
1017 if (prev && reclaim->generation != iter->generation) {
1018 iter->last_visited = NULL;
1022 last_visited = mem_cgroup_iter_load(iter, root, &seq);
1025 memcg = __mem_cgroup_iter_next(root, last_visited);
1028 mem_cgroup_iter_update(iter, last_visited, memcg, seq);
1032 else if (!prev && memcg)
1033 reclaim->generation = iter->generation;
1042 if (prev && prev != root)
1043 css_put(&prev->css);
1049 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1050 * @root: hierarchy root
1051 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1053 void mem_cgroup_iter_break(struct mem_cgroup *root,
1054 struct mem_cgroup *prev)
1057 root = root_mem_cgroup;
1058 if (prev && prev != root)
1059 css_put(&prev->css);
1063 * Iteration constructs for visiting all cgroups (under a tree). If
1064 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1065 * be used for reference counting.
1067 #define for_each_mem_cgroup_tree(iter, root) \
1068 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1070 iter = mem_cgroup_iter(root, iter, NULL))
1072 #define for_each_mem_cgroup(iter) \
1073 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1075 iter = mem_cgroup_iter(NULL, iter, NULL))
1077 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1079 struct mem_cgroup *memcg;
1082 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1083 if (unlikely(!memcg))
1088 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1091 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1099 EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1102 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1103 * @zone: zone of the wanted lruvec
1104 * @memcg: memcg of the wanted lruvec
1106 * Returns the lru list vector holding pages for the given @zone and
1107 * @mem. This can be the global zone lruvec, if the memory controller
1110 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1111 struct mem_cgroup *memcg)
1113 struct mem_cgroup_per_zone *mz;
1114 struct lruvec *lruvec;
1116 if (mem_cgroup_disabled()) {
1117 lruvec = &zone->lruvec;
1121 mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
1122 lruvec = &mz->lruvec;
1125 * Since a node can be onlined after the mem_cgroup was created,
1126 * we have to be prepared to initialize lruvec->zone here;
1127 * and if offlined then reonlined, we need to reinitialize it.
1129 if (unlikely(lruvec->zone != zone))
1130 lruvec->zone = zone;
1135 * Following LRU functions are allowed to be used without PCG_LOCK.
1136 * Operations are called by routine of global LRU independently from memcg.
1137 * What we have to take care of here is validness of pc->mem_cgroup.
1139 * Changes to pc->mem_cgroup happens when
1142 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1143 * It is added to LRU before charge.
1144 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1145 * When moving account, the page is not on LRU. It's isolated.
1149 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1151 * @zone: zone of the page
1153 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1155 struct mem_cgroup_per_zone *mz;
1156 struct mem_cgroup *memcg;
1157 struct page_cgroup *pc;
1158 struct lruvec *lruvec;
1160 if (mem_cgroup_disabled()) {
1161 lruvec = &zone->lruvec;
1165 pc = lookup_page_cgroup(page);
1166 memcg = pc->mem_cgroup;
1169 * Surreptitiously switch any uncharged offlist page to root:
1170 * an uncharged page off lru does nothing to secure
1171 * its former mem_cgroup from sudden removal.
1173 * Our caller holds lru_lock, and PageCgroupUsed is updated
1174 * under page_cgroup lock: between them, they make all uses
1175 * of pc->mem_cgroup safe.
1177 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1178 pc->mem_cgroup = memcg = root_mem_cgroup;
1180 mz = page_cgroup_zoneinfo(memcg, page);
1181 lruvec = &mz->lruvec;
1184 * Since a node can be onlined after the mem_cgroup was created,
1185 * we have to be prepared to initialize lruvec->zone here;
1186 * and if offlined then reonlined, we need to reinitialize it.
1188 if (unlikely(lruvec->zone != zone))
1189 lruvec->zone = zone;
1194 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1195 * @lruvec: mem_cgroup per zone lru vector
1196 * @lru: index of lru list the page is sitting on
1197 * @nr_pages: positive when adding or negative when removing
1199 * This function must be called when a page is added to or removed from an
1202 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1205 struct mem_cgroup_per_zone *mz;
1206 unsigned long *lru_size;
1208 if (mem_cgroup_disabled())
1211 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1212 lru_size = mz->lru_size + lru;
1213 *lru_size += nr_pages;
1214 VM_BUG_ON((long)(*lru_size) < 0);
1218 * Checks whether given mem is same or in the root_mem_cgroup's
1221 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1222 struct mem_cgroup *memcg)
1224 if (root_memcg == memcg)
1226 if (!root_memcg->use_hierarchy || !memcg)
1228 return css_is_ancestor(&memcg->css, &root_memcg->css);
1231 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1232 struct mem_cgroup *memcg)
1237 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1242 bool task_in_mem_cgroup(struct task_struct *task,
1243 const struct mem_cgroup *memcg)
1245 struct mem_cgroup *curr = NULL;
1246 struct task_struct *p;
1249 p = find_lock_task_mm(task);
1251 curr = try_get_mem_cgroup_from_mm(p->mm);
1255 * All threads may have already detached their mm's, but the oom
1256 * killer still needs to detect if they have already been oom
1257 * killed to prevent needlessly killing additional tasks.
1260 curr = mem_cgroup_from_task(task);
1262 css_get(&curr->css);
1268 * We should check use_hierarchy of "memcg" not "curr". Because checking
1269 * use_hierarchy of "curr" here make this function true if hierarchy is
1270 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1271 * hierarchy(even if use_hierarchy is disabled in "memcg").
1273 ret = mem_cgroup_same_or_subtree(memcg, curr);
1274 css_put(&curr->css);
1278 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1280 unsigned long inactive_ratio;
1281 unsigned long inactive;
1282 unsigned long active;
1285 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1286 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1288 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1290 inactive_ratio = int_sqrt(10 * gb);
1294 return inactive * inactive_ratio < active;
1297 #define mem_cgroup_from_res_counter(counter, member) \
1298 container_of(counter, struct mem_cgroup, member)
1301 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1302 * @memcg: the memory cgroup
1304 * Returns the maximum amount of memory @mem can be charged with, in
1307 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1309 unsigned long long margin;
1311 margin = res_counter_margin(&memcg->res);
1312 if (do_swap_account)
1313 margin = min(margin, res_counter_margin(&memcg->memsw));
1314 return margin >> PAGE_SHIFT;
1317 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1320 if (!css_parent(&memcg->css))
1321 return vm_swappiness;
1323 return memcg->swappiness;
1327 * memcg->moving_account is used for checking possibility that some thread is
1328 * calling move_account(). When a thread on CPU-A starts moving pages under
1329 * a memcg, other threads should check memcg->moving_account under
1330 * rcu_read_lock(), like this:
1334 * memcg->moving_account+1 if (memcg->mocing_account)
1336 * synchronize_rcu() update something.
1341 /* for quick checking without looking up memcg */
1342 atomic_t memcg_moving __read_mostly;
1344 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1346 atomic_inc(&memcg_moving);
1347 atomic_inc(&memcg->moving_account);
1351 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1354 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1355 * We check NULL in callee rather than caller.
1358 atomic_dec(&memcg_moving);
1359 atomic_dec(&memcg->moving_account);
1364 * 2 routines for checking "mem" is under move_account() or not.
1366 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1367 * is used for avoiding races in accounting. If true,
1368 * pc->mem_cgroup may be overwritten.
1370 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1371 * under hierarchy of moving cgroups. This is for
1372 * waiting at hith-memory prressure caused by "move".
1375 static bool mem_cgroup_stolen(struct mem_cgroup *memcg)
1377 VM_BUG_ON(!rcu_read_lock_held());
1378 return atomic_read(&memcg->moving_account) > 0;
1381 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1383 struct mem_cgroup *from;
1384 struct mem_cgroup *to;
1387 * Unlike task_move routines, we access mc.to, mc.from not under
1388 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1390 spin_lock(&mc.lock);
1396 ret = mem_cgroup_same_or_subtree(memcg, from)
1397 || mem_cgroup_same_or_subtree(memcg, to);
1399 spin_unlock(&mc.lock);
1403 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1405 if (mc.moving_task && current != mc.moving_task) {
1406 if (mem_cgroup_under_move(memcg)) {
1408 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1409 /* moving charge context might have finished. */
1412 finish_wait(&mc.waitq, &wait);
1420 * Take this lock when
1421 * - a code tries to modify page's memcg while it's USED.
1422 * - a code tries to modify page state accounting in a memcg.
1423 * see mem_cgroup_stolen(), too.
1425 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1426 unsigned long *flags)
1428 spin_lock_irqsave(&memcg->move_lock, *flags);
1431 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1432 unsigned long *flags)
1434 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1437 #define K(x) ((x) << (PAGE_SHIFT-10))
1439 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1440 * @memcg: The memory cgroup that went over limit
1441 * @p: Task that is going to be killed
1443 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1446 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1448 struct cgroup *task_cgrp;
1449 struct cgroup *mem_cgrp;
1451 * Need a buffer in BSS, can't rely on allocations. The code relies
1452 * on the assumption that OOM is serialized for memory controller.
1453 * If this assumption is broken, revisit this code.
1455 static char memcg_name[PATH_MAX];
1457 struct mem_cgroup *iter;
1465 mem_cgrp = memcg->css.cgroup;
1466 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1468 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1471 * Unfortunately, we are unable to convert to a useful name
1472 * But we'll still print out the usage information
1479 pr_info("Task in %s killed", memcg_name);
1482 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1490 * Continues from above, so we don't need an KERN_ level
1492 pr_cont(" as a result of limit of %s\n", memcg_name);
1495 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1496 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1497 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1498 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1499 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1500 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1501 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1502 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1503 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1504 res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1505 res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1506 res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
1508 for_each_mem_cgroup_tree(iter, memcg) {
1509 pr_info("Memory cgroup stats");
1512 ret = cgroup_path(iter->css.cgroup, memcg_name, PATH_MAX);
1514 pr_cont(" for %s", memcg_name);
1518 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1519 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1521 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1522 K(mem_cgroup_read_stat(iter, i)));
1525 for (i = 0; i < NR_LRU_LISTS; i++)
1526 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1527 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1534 * This function returns the number of memcg under hierarchy tree. Returns
1535 * 1(self count) if no children.
1537 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1540 struct mem_cgroup *iter;
1542 for_each_mem_cgroup_tree(iter, memcg)
1548 * Return the memory (and swap, if configured) limit for a memcg.
1550 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1554 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1557 * Do not consider swap space if we cannot swap due to swappiness
1559 if (mem_cgroup_swappiness(memcg)) {
1562 limit += total_swap_pages << PAGE_SHIFT;
1563 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1566 * If memsw is finite and limits the amount of swap space
1567 * available to this memcg, return that limit.
1569 limit = min(limit, memsw);
1575 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1578 struct mem_cgroup *iter;
1579 unsigned long chosen_points = 0;
1580 unsigned long totalpages;
1581 unsigned int points = 0;
1582 struct task_struct *chosen = NULL;
1585 * If current has a pending SIGKILL or is exiting, then automatically
1586 * select it. The goal is to allow it to allocate so that it may
1587 * quickly exit and free its memory.
1589 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1590 set_thread_flag(TIF_MEMDIE);
1594 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1595 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1596 for_each_mem_cgroup_tree(iter, memcg) {
1597 struct css_task_iter it;
1598 struct task_struct *task;
1600 css_task_iter_start(&iter->css, &it);
1601 while ((task = css_task_iter_next(&it))) {
1602 switch (oom_scan_process_thread(task, totalpages, NULL,
1604 case OOM_SCAN_SELECT:
1606 put_task_struct(chosen);
1608 chosen_points = ULONG_MAX;
1609 get_task_struct(chosen);
1611 case OOM_SCAN_CONTINUE:
1613 case OOM_SCAN_ABORT:
1614 css_task_iter_end(&it);
1615 mem_cgroup_iter_break(memcg, iter);
1617 put_task_struct(chosen);
1622 points = oom_badness(task, memcg, NULL, totalpages);
1623 if (points > chosen_points) {
1625 put_task_struct(chosen);
1627 chosen_points = points;
1628 get_task_struct(chosen);
1631 css_task_iter_end(&it);
1636 points = chosen_points * 1000 / totalpages;
1637 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1638 NULL, "Memory cgroup out of memory");
1641 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1643 unsigned long flags)
1645 unsigned long total = 0;
1646 bool noswap = false;
1649 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1651 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1654 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1656 drain_all_stock_async(memcg);
1657 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1659 * Allow limit shrinkers, which are triggered directly
1660 * by userspace, to catch signals and stop reclaim
1661 * after minimal progress, regardless of the margin.
1663 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1665 if (mem_cgroup_margin(memcg))
1668 * If nothing was reclaimed after two attempts, there
1669 * may be no reclaimable pages in this hierarchy.
1677 #if MAX_NUMNODES > 1
1679 * test_mem_cgroup_node_reclaimable
1680 * @memcg: the target memcg
1681 * @nid: the node ID to be checked.
1682 * @noswap : specify true here if the user wants flle only information.
1684 * This function returns whether the specified memcg contains any
1685 * reclaimable pages on a node. Returns true if there are any reclaimable
1686 * pages in the node.
1688 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1689 int nid, bool noswap)
1691 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1693 if (noswap || !total_swap_pages)
1695 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1702 * Always updating the nodemask is not very good - even if we have an empty
1703 * list or the wrong list here, we can start from some node and traverse all
1704 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1707 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1711 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1712 * pagein/pageout changes since the last update.
1714 if (!atomic_read(&memcg->numainfo_events))
1716 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1719 /* make a nodemask where this memcg uses memory from */
1720 memcg->scan_nodes = node_states[N_MEMORY];
1722 for_each_node_mask(nid, node_states[N_MEMORY]) {
1724 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1725 node_clear(nid, memcg->scan_nodes);
1728 atomic_set(&memcg->numainfo_events, 0);
1729 atomic_set(&memcg->numainfo_updating, 0);
1733 * Selecting a node where we start reclaim from. Because what we need is just
1734 * reducing usage counter, start from anywhere is O,K. Considering
1735 * memory reclaim from current node, there are pros. and cons.
1737 * Freeing memory from current node means freeing memory from a node which
1738 * we'll use or we've used. So, it may make LRU bad. And if several threads
1739 * hit limits, it will see a contention on a node. But freeing from remote
1740 * node means more costs for memory reclaim because of memory latency.
1742 * Now, we use round-robin. Better algorithm is welcomed.
1744 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1748 mem_cgroup_may_update_nodemask(memcg);
1749 node = memcg->last_scanned_node;
1751 node = next_node(node, memcg->scan_nodes);
1752 if (node == MAX_NUMNODES)
1753 node = first_node(memcg->scan_nodes);
1755 * We call this when we hit limit, not when pages are added to LRU.
1756 * No LRU may hold pages because all pages are UNEVICTABLE or
1757 * memcg is too small and all pages are not on LRU. In that case,
1758 * we use curret node.
1760 if (unlikely(node == MAX_NUMNODES))
1761 node = numa_node_id();
1763 memcg->last_scanned_node = node;
1768 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1776 * A group is eligible for the soft limit reclaim if it is
1777 * a) is over its soft limit
1778 * b) any parent up the hierarchy is over its soft limit
1780 bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg)
1782 struct mem_cgroup *parent = memcg;
1784 if (res_counter_soft_limit_excess(&memcg->res))
1788 * If any parent up the hierarchy is over its soft limit then we
1789 * have to obey and reclaim from this group as well.
1791 while((parent = parent_mem_cgroup(parent))) {
1792 if (res_counter_soft_limit_excess(&parent->res))
1800 * Check OOM-Killer is already running under our hierarchy.
1801 * If someone is running, return false.
1802 * Has to be called with memcg_oom_lock
1804 static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
1806 struct mem_cgroup *iter, *failed = NULL;
1808 for_each_mem_cgroup_tree(iter, memcg) {
1809 if (iter->oom_lock) {
1811 * this subtree of our hierarchy is already locked
1812 * so we cannot give a lock.
1815 mem_cgroup_iter_break(memcg, iter);
1818 iter->oom_lock = true;
1825 * OK, we failed to lock the whole subtree so we have to clean up
1826 * what we set up to the failing subtree
1828 for_each_mem_cgroup_tree(iter, memcg) {
1829 if (iter == failed) {
1830 mem_cgroup_iter_break(memcg, iter);
1833 iter->oom_lock = false;
1839 * Has to be called with memcg_oom_lock
1841 static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1843 struct mem_cgroup *iter;
1845 for_each_mem_cgroup_tree(iter, memcg)
1846 iter->oom_lock = false;
1850 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1852 struct mem_cgroup *iter;
1854 for_each_mem_cgroup_tree(iter, memcg)
1855 atomic_inc(&iter->under_oom);
1858 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1860 struct mem_cgroup *iter;
1863 * When a new child is created while the hierarchy is under oom,
1864 * mem_cgroup_oom_lock() may not be called. We have to use
1865 * atomic_add_unless() here.
1867 for_each_mem_cgroup_tree(iter, memcg)
1868 atomic_add_unless(&iter->under_oom, -1, 0);
1871 static DEFINE_SPINLOCK(memcg_oom_lock);
1872 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1874 struct oom_wait_info {
1875 struct mem_cgroup *memcg;
1879 static int memcg_oom_wake_function(wait_queue_t *wait,
1880 unsigned mode, int sync, void *arg)
1882 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1883 struct mem_cgroup *oom_wait_memcg;
1884 struct oom_wait_info *oom_wait_info;
1886 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1887 oom_wait_memcg = oom_wait_info->memcg;
1890 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
1891 * Then we can use css_is_ancestor without taking care of RCU.
1893 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
1894 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
1896 return autoremove_wake_function(wait, mode, sync, arg);
1899 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1901 /* for filtering, pass "memcg" as argument. */
1902 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1905 static void memcg_oom_recover(struct mem_cgroup *memcg)
1907 if (memcg && atomic_read(&memcg->under_oom))
1908 memcg_wakeup_oom(memcg);
1912 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1914 static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask,
1917 struct oom_wait_info owait;
1918 bool locked, need_to_kill;
1920 owait.memcg = memcg;
1921 owait.wait.flags = 0;
1922 owait.wait.func = memcg_oom_wake_function;
1923 owait.wait.private = current;
1924 INIT_LIST_HEAD(&owait.wait.task_list);
1925 need_to_kill = true;
1926 mem_cgroup_mark_under_oom(memcg);
1928 /* At first, try to OOM lock hierarchy under memcg.*/
1929 spin_lock(&memcg_oom_lock);
1930 locked = mem_cgroup_oom_lock(memcg);
1932 * Even if signal_pending(), we can't quit charge() loop without
1933 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1934 * under OOM is always welcomed, use TASK_KILLABLE here.
1936 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1937 if (!locked || memcg->oom_kill_disable)
1938 need_to_kill = false;
1940 mem_cgroup_oom_notify(memcg);
1941 spin_unlock(&memcg_oom_lock);
1944 finish_wait(&memcg_oom_waitq, &owait.wait);
1945 mem_cgroup_out_of_memory(memcg, mask, order);
1948 finish_wait(&memcg_oom_waitq, &owait.wait);
1950 spin_lock(&memcg_oom_lock);
1952 mem_cgroup_oom_unlock(memcg);
1953 memcg_wakeup_oom(memcg);
1954 spin_unlock(&memcg_oom_lock);
1956 mem_cgroup_unmark_under_oom(memcg);
1958 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1960 /* Give chance to dying process */
1961 schedule_timeout_uninterruptible(1);
1966 * Currently used to update mapped file statistics, but the routine can be
1967 * generalized to update other statistics as well.
1969 * Notes: Race condition
1971 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1972 * it tends to be costly. But considering some conditions, we doesn't need
1973 * to do so _always_.
1975 * Considering "charge", lock_page_cgroup() is not required because all
1976 * file-stat operations happen after a page is attached to radix-tree. There
1977 * are no race with "charge".
1979 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1980 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1981 * if there are race with "uncharge". Statistics itself is properly handled
1984 * Considering "move", this is an only case we see a race. To make the race
1985 * small, we check mm->moving_account and detect there are possibility of race
1986 * If there is, we take a lock.
1989 void __mem_cgroup_begin_update_page_stat(struct page *page,
1990 bool *locked, unsigned long *flags)
1992 struct mem_cgroup *memcg;
1993 struct page_cgroup *pc;
1995 pc = lookup_page_cgroup(page);
1997 memcg = pc->mem_cgroup;
1998 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2001 * If this memory cgroup is not under account moving, we don't
2002 * need to take move_lock_mem_cgroup(). Because we already hold
2003 * rcu_read_lock(), any calls to move_account will be delayed until
2004 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2006 if (!mem_cgroup_stolen(memcg))
2009 move_lock_mem_cgroup(memcg, flags);
2010 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2011 move_unlock_mem_cgroup(memcg, flags);
2017 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2019 struct page_cgroup *pc = lookup_page_cgroup(page);
2022 * It's guaranteed that pc->mem_cgroup never changes while
2023 * lock is held because a routine modifies pc->mem_cgroup
2024 * should take move_lock_mem_cgroup().
2026 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2029 void mem_cgroup_update_page_stat(struct page *page,
2030 enum mem_cgroup_page_stat_item idx, int val)
2032 struct mem_cgroup *memcg;
2033 struct page_cgroup *pc = lookup_page_cgroup(page);
2034 unsigned long uninitialized_var(flags);
2036 if (mem_cgroup_disabled())
2039 memcg = pc->mem_cgroup;
2040 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2044 case MEMCG_NR_FILE_MAPPED:
2045 idx = MEM_CGROUP_STAT_FILE_MAPPED;
2051 this_cpu_add(memcg->stat->count[idx], val);
2055 * size of first charge trial. "32" comes from vmscan.c's magic value.
2056 * TODO: maybe necessary to use big numbers in big irons.
2058 #define CHARGE_BATCH 32U
2059 struct memcg_stock_pcp {
2060 struct mem_cgroup *cached; /* this never be root cgroup */
2061 unsigned int nr_pages;
2062 struct work_struct work;
2063 unsigned long flags;
2064 #define FLUSHING_CACHED_CHARGE 0
2066 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2067 static DEFINE_MUTEX(percpu_charge_mutex);
2070 * consume_stock: Try to consume stocked charge on this cpu.
2071 * @memcg: memcg to consume from.
2072 * @nr_pages: how many pages to charge.
2074 * The charges will only happen if @memcg matches the current cpu's memcg
2075 * stock, and at least @nr_pages are available in that stock. Failure to
2076 * service an allocation will refill the stock.
2078 * returns true if successful, false otherwise.
2080 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2082 struct memcg_stock_pcp *stock;
2085 if (nr_pages > CHARGE_BATCH)
2088 stock = &get_cpu_var(memcg_stock);
2089 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2090 stock->nr_pages -= nr_pages;
2091 else /* need to call res_counter_charge */
2093 put_cpu_var(memcg_stock);
2098 * Returns stocks cached in percpu to res_counter and reset cached information.
2100 static void drain_stock(struct memcg_stock_pcp *stock)
2102 struct mem_cgroup *old = stock->cached;
2104 if (stock->nr_pages) {
2105 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2107 res_counter_uncharge(&old->res, bytes);
2108 if (do_swap_account)
2109 res_counter_uncharge(&old->memsw, bytes);
2110 stock->nr_pages = 0;
2112 stock->cached = NULL;
2116 * This must be called under preempt disabled or must be called by
2117 * a thread which is pinned to local cpu.
2119 static void drain_local_stock(struct work_struct *dummy)
2121 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2123 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2126 static void __init memcg_stock_init(void)
2130 for_each_possible_cpu(cpu) {
2131 struct memcg_stock_pcp *stock =
2132 &per_cpu(memcg_stock, cpu);
2133 INIT_WORK(&stock->work, drain_local_stock);
2138 * Cache charges(val) which is from res_counter, to local per_cpu area.
2139 * This will be consumed by consume_stock() function, later.
2141 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2143 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2145 if (stock->cached != memcg) { /* reset if necessary */
2147 stock->cached = memcg;
2149 stock->nr_pages += nr_pages;
2150 put_cpu_var(memcg_stock);
2154 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2155 * of the hierarchy under it. sync flag says whether we should block
2156 * until the work is done.
2158 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2162 /* Notify other cpus that system-wide "drain" is running */
2165 for_each_online_cpu(cpu) {
2166 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2167 struct mem_cgroup *memcg;
2169 memcg = stock->cached;
2170 if (!memcg || !stock->nr_pages)
2172 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2174 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2176 drain_local_stock(&stock->work);
2178 schedule_work_on(cpu, &stock->work);
2186 for_each_online_cpu(cpu) {
2187 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2188 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2189 flush_work(&stock->work);
2196 * Tries to drain stocked charges in other cpus. This function is asynchronous
2197 * and just put a work per cpu for draining localy on each cpu. Caller can
2198 * expects some charges will be back to res_counter later but cannot wait for
2201 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2204 * If someone calls draining, avoid adding more kworker runs.
2206 if (!mutex_trylock(&percpu_charge_mutex))
2208 drain_all_stock(root_memcg, false);
2209 mutex_unlock(&percpu_charge_mutex);
2212 /* This is a synchronous drain interface. */
2213 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2215 /* called when force_empty is called */
2216 mutex_lock(&percpu_charge_mutex);
2217 drain_all_stock(root_memcg, true);
2218 mutex_unlock(&percpu_charge_mutex);
2222 * This function drains percpu counter value from DEAD cpu and
2223 * move it to local cpu. Note that this function can be preempted.
2225 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2229 spin_lock(&memcg->pcp_counter_lock);
2230 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2231 long x = per_cpu(memcg->stat->count[i], cpu);
2233 per_cpu(memcg->stat->count[i], cpu) = 0;
2234 memcg->nocpu_base.count[i] += x;
2236 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2237 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2239 per_cpu(memcg->stat->events[i], cpu) = 0;
2240 memcg->nocpu_base.events[i] += x;
2242 spin_unlock(&memcg->pcp_counter_lock);
2245 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2246 unsigned long action,
2249 int cpu = (unsigned long)hcpu;
2250 struct memcg_stock_pcp *stock;
2251 struct mem_cgroup *iter;
2253 if (action == CPU_ONLINE)
2256 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2259 for_each_mem_cgroup(iter)
2260 mem_cgroup_drain_pcp_counter(iter, cpu);
2262 stock = &per_cpu(memcg_stock, cpu);
2268 /* See __mem_cgroup_try_charge() for details */
2270 CHARGE_OK, /* success */
2271 CHARGE_RETRY, /* need to retry but retry is not bad */
2272 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2273 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
2274 CHARGE_OOM_DIE, /* the current is killed because of OOM */
2277 static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2278 unsigned int nr_pages, unsigned int min_pages,
2281 unsigned long csize = nr_pages * PAGE_SIZE;
2282 struct mem_cgroup *mem_over_limit;
2283 struct res_counter *fail_res;
2284 unsigned long flags = 0;
2287 ret = res_counter_charge(&memcg->res, csize, &fail_res);
2290 if (!do_swap_account)
2292 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2296 res_counter_uncharge(&memcg->res, csize);
2297 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2298 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2300 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2302 * Never reclaim on behalf of optional batching, retry with a
2303 * single page instead.
2305 if (nr_pages > min_pages)
2306 return CHARGE_RETRY;
2308 if (!(gfp_mask & __GFP_WAIT))
2309 return CHARGE_WOULDBLOCK;
2311 if (gfp_mask & __GFP_NORETRY)
2312 return CHARGE_NOMEM;
2314 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2315 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2316 return CHARGE_RETRY;
2318 * Even though the limit is exceeded at this point, reclaim
2319 * may have been able to free some pages. Retry the charge
2320 * before killing the task.
2322 * Only for regular pages, though: huge pages are rather
2323 * unlikely to succeed so close to the limit, and we fall back
2324 * to regular pages anyway in case of failure.
2326 if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
2327 return CHARGE_RETRY;
2330 * At task move, charge accounts can be doubly counted. So, it's
2331 * better to wait until the end of task_move if something is going on.
2333 if (mem_cgroup_wait_acct_move(mem_over_limit))
2334 return CHARGE_RETRY;
2336 /* If we don't need to call oom-killer at el, return immediately */
2338 return CHARGE_NOMEM;
2340 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))
2341 return CHARGE_OOM_DIE;
2343 return CHARGE_RETRY;
2347 * __mem_cgroup_try_charge() does
2348 * 1. detect memcg to be charged against from passed *mm and *ptr,
2349 * 2. update res_counter
2350 * 3. call memory reclaim if necessary.
2352 * In some special case, if the task is fatal, fatal_signal_pending() or
2353 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2354 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2355 * as possible without any hazards. 2: all pages should have a valid
2356 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2357 * pointer, that is treated as a charge to root_mem_cgroup.
2359 * So __mem_cgroup_try_charge() will return
2360 * 0 ... on success, filling *ptr with a valid memcg pointer.
2361 * -ENOMEM ... charge failure because of resource limits.
2362 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2364 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2365 * the oom-killer can be invoked.
2367 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2369 unsigned int nr_pages,
2370 struct mem_cgroup **ptr,
2373 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2374 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2375 struct mem_cgroup *memcg = NULL;
2379 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2380 * in system level. So, allow to go ahead dying process in addition to
2383 if (unlikely(test_thread_flag(TIF_MEMDIE)
2384 || fatal_signal_pending(current)))
2388 * We always charge the cgroup the mm_struct belongs to.
2389 * The mm_struct's mem_cgroup changes on task migration if the
2390 * thread group leader migrates. It's possible that mm is not
2391 * set, if so charge the root memcg (happens for pagecache usage).
2394 *ptr = root_mem_cgroup;
2396 if (*ptr) { /* css should be a valid one */
2398 if (mem_cgroup_is_root(memcg))
2400 if (consume_stock(memcg, nr_pages))
2402 css_get(&memcg->css);
2404 struct task_struct *p;
2407 p = rcu_dereference(mm->owner);
2409 * Because we don't have task_lock(), "p" can exit.
2410 * In that case, "memcg" can point to root or p can be NULL with
2411 * race with swapoff. Then, we have small risk of mis-accouning.
2412 * But such kind of mis-account by race always happens because
2413 * we don't have cgroup_mutex(). It's overkill and we allo that
2415 * (*) swapoff at el will charge against mm-struct not against
2416 * task-struct. So, mm->owner can be NULL.
2418 memcg = mem_cgroup_from_task(p);
2420 memcg = root_mem_cgroup;
2421 if (mem_cgroup_is_root(memcg)) {
2425 if (consume_stock(memcg, nr_pages)) {
2427 * It seems dagerous to access memcg without css_get().
2428 * But considering how consume_stok works, it's not
2429 * necessary. If consume_stock success, some charges
2430 * from this memcg are cached on this cpu. So, we
2431 * don't need to call css_get()/css_tryget() before
2432 * calling consume_stock().
2437 /* after here, we may be blocked. we need to get refcnt */
2438 if (!css_tryget(&memcg->css)) {
2448 /* If killed, bypass charge */
2449 if (fatal_signal_pending(current)) {
2450 css_put(&memcg->css);
2455 if (oom && !nr_oom_retries) {
2457 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2460 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
2465 case CHARGE_RETRY: /* not in OOM situation but retry */
2467 css_put(&memcg->css);
2470 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2471 css_put(&memcg->css);
2473 case CHARGE_NOMEM: /* OOM routine works */
2475 css_put(&memcg->css);
2478 /* If oom, we never return -ENOMEM */
2481 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2482 css_put(&memcg->css);
2485 } while (ret != CHARGE_OK);
2487 if (batch > nr_pages)
2488 refill_stock(memcg, batch - nr_pages);
2489 css_put(&memcg->css);
2497 *ptr = root_mem_cgroup;
2502 * Somemtimes we have to undo a charge we got by try_charge().
2503 * This function is for that and do uncharge, put css's refcnt.
2504 * gotten by try_charge().
2506 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2507 unsigned int nr_pages)
2509 if (!mem_cgroup_is_root(memcg)) {
2510 unsigned long bytes = nr_pages * PAGE_SIZE;
2512 res_counter_uncharge(&memcg->res, bytes);
2513 if (do_swap_account)
2514 res_counter_uncharge(&memcg->memsw, bytes);
2519 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2520 * This is useful when moving usage to parent cgroup.
2522 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2523 unsigned int nr_pages)
2525 unsigned long bytes = nr_pages * PAGE_SIZE;
2527 if (mem_cgroup_is_root(memcg))
2530 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2531 if (do_swap_account)
2532 res_counter_uncharge_until(&memcg->memsw,
2533 memcg->memsw.parent, bytes);
2537 * A helper function to get mem_cgroup from ID. must be called under
2538 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2539 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2540 * called against removed memcg.)
2542 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2544 struct cgroup_subsys_state *css;
2546 /* ID 0 is unused ID */
2549 css = css_lookup(&mem_cgroup_subsys, id);
2552 return mem_cgroup_from_css(css);
2555 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2557 struct mem_cgroup *memcg = NULL;
2558 struct page_cgroup *pc;
2562 VM_BUG_ON(!PageLocked(page));
2564 pc = lookup_page_cgroup(page);
2565 lock_page_cgroup(pc);
2566 if (PageCgroupUsed(pc)) {
2567 memcg = pc->mem_cgroup;
2568 if (memcg && !css_tryget(&memcg->css))
2570 } else if (PageSwapCache(page)) {
2571 ent.val = page_private(page);
2572 id = lookup_swap_cgroup_id(ent);
2574 memcg = mem_cgroup_lookup(id);
2575 if (memcg && !css_tryget(&memcg->css))
2579 unlock_page_cgroup(pc);
2583 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2585 unsigned int nr_pages,
2586 enum charge_type ctype,
2589 struct page_cgroup *pc = lookup_page_cgroup(page);
2590 struct zone *uninitialized_var(zone);
2591 struct lruvec *lruvec;
2592 bool was_on_lru = false;
2595 lock_page_cgroup(pc);
2596 VM_BUG_ON(PageCgroupUsed(pc));
2598 * we don't need page_cgroup_lock about tail pages, becase they are not
2599 * accessed by any other context at this point.
2603 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2604 * may already be on some other mem_cgroup's LRU. Take care of it.
2607 zone = page_zone(page);
2608 spin_lock_irq(&zone->lru_lock);
2609 if (PageLRU(page)) {
2610 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2612 del_page_from_lru_list(page, lruvec, page_lru(page));
2617 pc->mem_cgroup = memcg;
2619 * We access a page_cgroup asynchronously without lock_page_cgroup().
2620 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2621 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2622 * before USED bit, we need memory barrier here.
2623 * See mem_cgroup_add_lru_list(), etc.
2626 SetPageCgroupUsed(pc);
2630 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2631 VM_BUG_ON(PageLRU(page));
2633 add_page_to_lru_list(page, lruvec, page_lru(page));
2635 spin_unlock_irq(&zone->lru_lock);
2638 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2643 mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
2644 unlock_page_cgroup(pc);
2647 * "charge_statistics" updated event counter.
2649 memcg_check_events(memcg, page);
2652 static DEFINE_MUTEX(set_limit_mutex);
2654 #ifdef CONFIG_MEMCG_KMEM
2655 static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2657 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2658 (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK);
2662 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2663 * in the memcg_cache_params struct.
2665 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2667 struct kmem_cache *cachep;
2669 VM_BUG_ON(p->is_root_cache);
2670 cachep = p->root_cache;
2671 return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)];
2674 #ifdef CONFIG_SLABINFO
2675 static int mem_cgroup_slabinfo_read(struct cgroup_subsys_state *css,
2676 struct cftype *cft, struct seq_file *m)
2678 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
2679 struct memcg_cache_params *params;
2681 if (!memcg_can_account_kmem(memcg))
2684 print_slabinfo_header(m);
2686 mutex_lock(&memcg->slab_caches_mutex);
2687 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2688 cache_show(memcg_params_to_cache(params), m);
2689 mutex_unlock(&memcg->slab_caches_mutex);
2695 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2697 struct res_counter *fail_res;
2698 struct mem_cgroup *_memcg;
2702 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2707 * Conditions under which we can wait for the oom_killer. Those are
2708 * the same conditions tested by the core page allocator
2710 may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY);
2713 ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT,
2716 if (ret == -EINTR) {
2718 * __mem_cgroup_try_charge() chosed to bypass to root due to
2719 * OOM kill or fatal signal. Since our only options are to
2720 * either fail the allocation or charge it to this cgroup, do
2721 * it as a temporary condition. But we can't fail. From a
2722 * kmem/slab perspective, the cache has already been selected,
2723 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2726 * This condition will only trigger if the task entered
2727 * memcg_charge_kmem in a sane state, but was OOM-killed during
2728 * __mem_cgroup_try_charge() above. Tasks that were already
2729 * dying when the allocation triggers should have been already
2730 * directed to the root cgroup in memcontrol.h
2732 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2733 if (do_swap_account)
2734 res_counter_charge_nofail(&memcg->memsw, size,
2738 res_counter_uncharge(&memcg->kmem, size);
2743 static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2745 res_counter_uncharge(&memcg->res, size);
2746 if (do_swap_account)
2747 res_counter_uncharge(&memcg->memsw, size);
2750 if (res_counter_uncharge(&memcg->kmem, size))
2754 * Releases a reference taken in kmem_cgroup_css_offline in case
2755 * this last uncharge is racing with the offlining code or it is
2756 * outliving the memcg existence.
2758 * The memory barrier imposed by test&clear is paired with the
2759 * explicit one in memcg_kmem_mark_dead().
2761 if (memcg_kmem_test_and_clear_dead(memcg))
2762 css_put(&memcg->css);
2765 void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep)
2770 mutex_lock(&memcg->slab_caches_mutex);
2771 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
2772 mutex_unlock(&memcg->slab_caches_mutex);
2776 * helper for acessing a memcg's index. It will be used as an index in the
2777 * child cache array in kmem_cache, and also to derive its name. This function
2778 * will return -1 when this is not a kmem-limited memcg.
2780 int memcg_cache_id(struct mem_cgroup *memcg)
2782 return memcg ? memcg->kmemcg_id : -1;
2786 * This ends up being protected by the set_limit mutex, during normal
2787 * operation, because that is its main call site.
2789 * But when we create a new cache, we can call this as well if its parent
2790 * is kmem-limited. That will have to hold set_limit_mutex as well.
2792 int memcg_update_cache_sizes(struct mem_cgroup *memcg)
2796 num = ida_simple_get(&kmem_limited_groups,
2797 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2801 * After this point, kmem_accounted (that we test atomically in
2802 * the beginning of this conditional), is no longer 0. This
2803 * guarantees only one process will set the following boolean
2804 * to true. We don't need test_and_set because we're protected
2805 * by the set_limit_mutex anyway.
2807 memcg_kmem_set_activated(memcg);
2809 ret = memcg_update_all_caches(num+1);
2811 ida_simple_remove(&kmem_limited_groups, num);
2812 memcg_kmem_clear_activated(memcg);
2816 memcg->kmemcg_id = num;
2817 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
2818 mutex_init(&memcg->slab_caches_mutex);
2822 static size_t memcg_caches_array_size(int num_groups)
2825 if (num_groups <= 0)
2828 size = 2 * num_groups;
2829 if (size < MEMCG_CACHES_MIN_SIZE)
2830 size = MEMCG_CACHES_MIN_SIZE;
2831 else if (size > MEMCG_CACHES_MAX_SIZE)
2832 size = MEMCG_CACHES_MAX_SIZE;
2838 * We should update the current array size iff all caches updates succeed. This
2839 * can only be done from the slab side. The slab mutex needs to be held when
2842 void memcg_update_array_size(int num)
2844 if (num > memcg_limited_groups_array_size)
2845 memcg_limited_groups_array_size = memcg_caches_array_size(num);
2848 static void kmem_cache_destroy_work_func(struct work_struct *w);
2850 int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
2852 struct memcg_cache_params *cur_params = s->memcg_params;
2854 VM_BUG_ON(s->memcg_params && !s->memcg_params->is_root_cache);
2856 if (num_groups > memcg_limited_groups_array_size) {
2858 ssize_t size = memcg_caches_array_size(num_groups);
2860 size *= sizeof(void *);
2861 size += offsetof(struct memcg_cache_params, memcg_caches);
2863 s->memcg_params = kzalloc(size, GFP_KERNEL);
2864 if (!s->memcg_params) {
2865 s->memcg_params = cur_params;
2869 s->memcg_params->is_root_cache = true;
2872 * There is the chance it will be bigger than
2873 * memcg_limited_groups_array_size, if we failed an allocation
2874 * in a cache, in which case all caches updated before it, will
2875 * have a bigger array.
2877 * But if that is the case, the data after
2878 * memcg_limited_groups_array_size is certainly unused
2880 for (i = 0; i < memcg_limited_groups_array_size; i++) {
2881 if (!cur_params->memcg_caches[i])
2883 s->memcg_params->memcg_caches[i] =
2884 cur_params->memcg_caches[i];
2888 * Ideally, we would wait until all caches succeed, and only
2889 * then free the old one. But this is not worth the extra
2890 * pointer per-cache we'd have to have for this.
2892 * It is not a big deal if some caches are left with a size
2893 * bigger than the others. And all updates will reset this
2901 int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
2902 struct kmem_cache *root_cache)
2906 if (!memcg_kmem_enabled())
2910 size = offsetof(struct memcg_cache_params, memcg_caches);
2911 size += memcg_limited_groups_array_size * sizeof(void *);
2913 size = sizeof(struct memcg_cache_params);
2915 s->memcg_params = kzalloc(size, GFP_KERNEL);
2916 if (!s->memcg_params)
2920 s->memcg_params->memcg = memcg;
2921 s->memcg_params->root_cache = root_cache;
2922 INIT_WORK(&s->memcg_params->destroy,
2923 kmem_cache_destroy_work_func);
2925 s->memcg_params->is_root_cache = true;
2930 void memcg_release_cache(struct kmem_cache *s)
2932 struct kmem_cache *root;
2933 struct mem_cgroup *memcg;
2937 * This happens, for instance, when a root cache goes away before we
2940 if (!s->memcg_params)
2943 if (s->memcg_params->is_root_cache)
2946 memcg = s->memcg_params->memcg;
2947 id = memcg_cache_id(memcg);
2949 root = s->memcg_params->root_cache;
2950 root->memcg_params->memcg_caches[id] = NULL;
2952 mutex_lock(&memcg->slab_caches_mutex);
2953 list_del(&s->memcg_params->list);
2954 mutex_unlock(&memcg->slab_caches_mutex);
2956 css_put(&memcg->css);
2958 kfree(s->memcg_params);
2962 * During the creation a new cache, we need to disable our accounting mechanism
2963 * altogether. This is true even if we are not creating, but rather just
2964 * enqueing new caches to be created.
2966 * This is because that process will trigger allocations; some visible, like
2967 * explicit kmallocs to auxiliary data structures, name strings and internal
2968 * cache structures; some well concealed, like INIT_WORK() that can allocate
2969 * objects during debug.
2971 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
2972 * to it. This may not be a bounded recursion: since the first cache creation
2973 * failed to complete (waiting on the allocation), we'll just try to create the
2974 * cache again, failing at the same point.
2976 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
2977 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
2978 * inside the following two functions.
2980 static inline void memcg_stop_kmem_account(void)
2982 VM_BUG_ON(!current->mm);
2983 current->memcg_kmem_skip_account++;
2986 static inline void memcg_resume_kmem_account(void)
2988 VM_BUG_ON(!current->mm);
2989 current->memcg_kmem_skip_account--;
2992 static void kmem_cache_destroy_work_func(struct work_struct *w)
2994 struct kmem_cache *cachep;
2995 struct memcg_cache_params *p;
2997 p = container_of(w, struct memcg_cache_params, destroy);
2999 cachep = memcg_params_to_cache(p);
3002 * If we get down to 0 after shrink, we could delete right away.
3003 * However, memcg_release_pages() already puts us back in the workqueue
3004 * in that case. If we proceed deleting, we'll get a dangling
3005 * reference, and removing the object from the workqueue in that case
3006 * is unnecessary complication. We are not a fast path.
3008 * Note that this case is fundamentally different from racing with
3009 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3010 * kmem_cache_shrink, not only we would be reinserting a dead cache
3011 * into the queue, but doing so from inside the worker racing to
3014 * So if we aren't down to zero, we'll just schedule a worker and try
3017 if (atomic_read(&cachep->memcg_params->nr_pages) != 0) {
3018 kmem_cache_shrink(cachep);
3019 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
3022 kmem_cache_destroy(cachep);
3025 void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
3027 if (!cachep->memcg_params->dead)
3031 * There are many ways in which we can get here.
3033 * We can get to a memory-pressure situation while the delayed work is
3034 * still pending to run. The vmscan shrinkers can then release all
3035 * cache memory and get us to destruction. If this is the case, we'll
3036 * be executed twice, which is a bug (the second time will execute over
3037 * bogus data). In this case, cancelling the work should be fine.
3039 * But we can also get here from the worker itself, if
3040 * kmem_cache_shrink is enough to shake all the remaining objects and
3041 * get the page count to 0. In this case, we'll deadlock if we try to
3042 * cancel the work (the worker runs with an internal lock held, which
3043 * is the same lock we would hold for cancel_work_sync().)
3045 * Since we can't possibly know who got us here, just refrain from
3046 * running if there is already work pending
3048 if (work_pending(&cachep->memcg_params->destroy))
3051 * We have to defer the actual destroying to a workqueue, because
3052 * we might currently be in a context that cannot sleep.
3054 schedule_work(&cachep->memcg_params->destroy);
3058 * This lock protects updaters, not readers. We want readers to be as fast as
3059 * they can, and they will either see NULL or a valid cache value. Our model
3060 * allow them to see NULL, in which case the root memcg will be selected.
3062 * We need this lock because multiple allocations to the same cache from a non
3063 * will span more than one worker. Only one of them can create the cache.
3065 static DEFINE_MUTEX(memcg_cache_mutex);
3068 * Called with memcg_cache_mutex held
3070 static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
3071 struct kmem_cache *s)
3073 struct kmem_cache *new;
3074 static char *tmp_name = NULL;
3076 lockdep_assert_held(&memcg_cache_mutex);
3079 * kmem_cache_create_memcg duplicates the given name and
3080 * cgroup_name for this name requires RCU context.
3081 * This static temporary buffer is used to prevent from
3082 * pointless shortliving allocation.
3085 tmp_name = kmalloc(PATH_MAX, GFP_KERNEL);
3091 snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name,
3092 memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup));
3095 new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align,
3096 (s->flags & ~SLAB_PANIC), s->ctor, s);
3099 new->allocflags |= __GFP_KMEMCG;
3104 static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
3105 struct kmem_cache *cachep)
3107 struct kmem_cache *new_cachep;
3110 BUG_ON(!memcg_can_account_kmem(memcg));
3112 idx = memcg_cache_id(memcg);
3114 mutex_lock(&memcg_cache_mutex);
3115 new_cachep = cachep->memcg_params->memcg_caches[idx];
3117 css_put(&memcg->css);
3121 new_cachep = kmem_cache_dup(memcg, cachep);
3122 if (new_cachep == NULL) {
3123 new_cachep = cachep;
3124 css_put(&memcg->css);
3128 atomic_set(&new_cachep->memcg_params->nr_pages , 0);
3130 cachep->memcg_params->memcg_caches[idx] = new_cachep;
3132 * the readers won't lock, make sure everybody sees the updated value,
3133 * so they won't put stuff in the queue again for no reason
3137 mutex_unlock(&memcg_cache_mutex);
3141 void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
3143 struct kmem_cache *c;
3146 if (!s->memcg_params)
3148 if (!s->memcg_params->is_root_cache)
3152 * If the cache is being destroyed, we trust that there is no one else
3153 * requesting objects from it. Even if there are, the sanity checks in
3154 * kmem_cache_destroy should caught this ill-case.
3156 * Still, we don't want anyone else freeing memcg_caches under our
3157 * noses, which can happen if a new memcg comes to life. As usual,
3158 * we'll take the set_limit_mutex to protect ourselves against this.
3160 mutex_lock(&set_limit_mutex);
3161 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3162 c = s->memcg_params->memcg_caches[i];
3167 * We will now manually delete the caches, so to avoid races
3168 * we need to cancel all pending destruction workers and
3169 * proceed with destruction ourselves.
3171 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3172 * and that could spawn the workers again: it is likely that
3173 * the cache still have active pages until this very moment.
3174 * This would lead us back to mem_cgroup_destroy_cache.
3176 * But that will not execute at all if the "dead" flag is not
3177 * set, so flip it down to guarantee we are in control.
3179 c->memcg_params->dead = false;
3180 cancel_work_sync(&c->memcg_params->destroy);
3181 kmem_cache_destroy(c);
3183 mutex_unlock(&set_limit_mutex);
3186 struct create_work {
3187 struct mem_cgroup *memcg;
3188 struct kmem_cache *cachep;
3189 struct work_struct work;
3192 static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3194 struct kmem_cache *cachep;
3195 struct memcg_cache_params *params;
3197 if (!memcg_kmem_is_active(memcg))
3200 mutex_lock(&memcg->slab_caches_mutex);
3201 list_for_each_entry(params, &memcg->memcg_slab_caches, list) {
3202 cachep = memcg_params_to_cache(params);
3203 cachep->memcg_params->dead = true;
3204 schedule_work(&cachep->memcg_params->destroy);
3206 mutex_unlock(&memcg->slab_caches_mutex);
3209 static void memcg_create_cache_work_func(struct work_struct *w)
3211 struct create_work *cw;
3213 cw = container_of(w, struct create_work, work);
3214 memcg_create_kmem_cache(cw->memcg, cw->cachep);
3219 * Enqueue the creation of a per-memcg kmem_cache.
3221 static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3222 struct kmem_cache *cachep)
3224 struct create_work *cw;
3226 cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT);
3228 css_put(&memcg->css);
3233 cw->cachep = cachep;
3235 INIT_WORK(&cw->work, memcg_create_cache_work_func);
3236 schedule_work(&cw->work);
3239 static void memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3240 struct kmem_cache *cachep)
3243 * We need to stop accounting when we kmalloc, because if the
3244 * corresponding kmalloc cache is not yet created, the first allocation
3245 * in __memcg_create_cache_enqueue will recurse.
3247 * However, it is better to enclose the whole function. Depending on
3248 * the debugging options enabled, INIT_WORK(), for instance, can
3249 * trigger an allocation. This too, will make us recurse. Because at
3250 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3251 * the safest choice is to do it like this, wrapping the whole function.
3253 memcg_stop_kmem_account();
3254 __memcg_create_cache_enqueue(memcg, cachep);
3255 memcg_resume_kmem_account();
3258 * Return the kmem_cache we're supposed to use for a slab allocation.
3259 * We try to use the current memcg's version of the cache.
3261 * If the cache does not exist yet, if we are the first user of it,
3262 * we either create it immediately, if possible, or create it asynchronously
3264 * In the latter case, we will let the current allocation go through with
3265 * the original cache.
3267 * Can't be called in interrupt context or from kernel threads.
3268 * This function needs to be called with rcu_read_lock() held.
3270 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3273 struct mem_cgroup *memcg;
3276 VM_BUG_ON(!cachep->memcg_params);
3277 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3279 if (!current->mm || current->memcg_kmem_skip_account)
3283 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3285 if (!memcg_can_account_kmem(memcg))
3288 idx = memcg_cache_id(memcg);
3291 * barrier to mare sure we're always seeing the up to date value. The
3292 * code updating memcg_caches will issue a write barrier to match this.
3294 read_barrier_depends();
3295 if (likely(cachep->memcg_params->memcg_caches[idx])) {
3296 cachep = cachep->memcg_params->memcg_caches[idx];
3300 /* The corresponding put will be done in the workqueue. */
3301 if (!css_tryget(&memcg->css))
3306 * If we are in a safe context (can wait, and not in interrupt
3307 * context), we could be be predictable and return right away.
3308 * This would guarantee that the allocation being performed
3309 * already belongs in the new cache.
3311 * However, there are some clashes that can arrive from locking.
3312 * For instance, because we acquire the slab_mutex while doing
3313 * kmem_cache_dup, this means no further allocation could happen
3314 * with the slab_mutex held.
3316 * Also, because cache creation issue get_online_cpus(), this
3317 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3318 * that ends up reversed during cpu hotplug. (cpuset allocates
3319 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3320 * better to defer everything.
3322 memcg_create_cache_enqueue(memcg, cachep);
3328 EXPORT_SYMBOL(__memcg_kmem_get_cache);
3331 * We need to verify if the allocation against current->mm->owner's memcg is
3332 * possible for the given order. But the page is not allocated yet, so we'll
3333 * need a further commit step to do the final arrangements.
3335 * It is possible for the task to switch cgroups in this mean time, so at
3336 * commit time, we can't rely on task conversion any longer. We'll then use
3337 * the handle argument to return to the caller which cgroup we should commit
3338 * against. We could also return the memcg directly and avoid the pointer
3339 * passing, but a boolean return value gives better semantics considering
3340 * the compiled-out case as well.
3342 * Returning true means the allocation is possible.
3345 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3347 struct mem_cgroup *memcg;
3353 * Disabling accounting is only relevant for some specific memcg
3354 * internal allocations. Therefore we would initially not have such
3355 * check here, since direct calls to the page allocator that are marked
3356 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3357 * concerned with cache allocations, and by having this test at
3358 * memcg_kmem_get_cache, we are already able to relay the allocation to
3359 * the root cache and bypass the memcg cache altogether.
3361 * There is one exception, though: the SLUB allocator does not create
3362 * large order caches, but rather service large kmallocs directly from
3363 * the page allocator. Therefore, the following sequence when backed by
3364 * the SLUB allocator:
3366 * memcg_stop_kmem_account();
3367 * kmalloc(<large_number>)
3368 * memcg_resume_kmem_account();
3370 * would effectively ignore the fact that we should skip accounting,
3371 * since it will drive us directly to this function without passing
3372 * through the cache selector memcg_kmem_get_cache. Such large
3373 * allocations are extremely rare but can happen, for instance, for the
3374 * cache arrays. We bring this test here.
3376 if (!current->mm || current->memcg_kmem_skip_account)
3379 memcg = try_get_mem_cgroup_from_mm(current->mm);
3382 * very rare case described in mem_cgroup_from_task. Unfortunately there
3383 * isn't much we can do without complicating this too much, and it would
3384 * be gfp-dependent anyway. Just let it go
3386 if (unlikely(!memcg))
3389 if (!memcg_can_account_kmem(memcg)) {
3390 css_put(&memcg->css);
3394 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3398 css_put(&memcg->css);
3402 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3405 struct page_cgroup *pc;
3407 VM_BUG_ON(mem_cgroup_is_root(memcg));
3409 /* The page allocation failed. Revert */
3411 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3415 pc = lookup_page_cgroup(page);
3416 lock_page_cgroup(pc);
3417 pc->mem_cgroup = memcg;
3418 SetPageCgroupUsed(pc);
3419 unlock_page_cgroup(pc);
3422 void __memcg_kmem_uncharge_pages(struct page *page, int order)
3424 struct mem_cgroup *memcg = NULL;
3425 struct page_cgroup *pc;
3428 pc = lookup_page_cgroup(page);
3430 * Fast unlocked return. Theoretically might have changed, have to
3431 * check again after locking.
3433 if (!PageCgroupUsed(pc))
3436 lock_page_cgroup(pc);
3437 if (PageCgroupUsed(pc)) {
3438 memcg = pc->mem_cgroup;
3439 ClearPageCgroupUsed(pc);
3441 unlock_page_cgroup(pc);
3444 * We trust that only if there is a memcg associated with the page, it
3445 * is a valid allocation
3450 VM_BUG_ON(mem_cgroup_is_root(memcg));
3451 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3454 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3457 #endif /* CONFIG_MEMCG_KMEM */
3459 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3461 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3463 * Because tail pages are not marked as "used", set it. We're under
3464 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3465 * charge/uncharge will be never happen and move_account() is done under
3466 * compound_lock(), so we don't have to take care of races.
3468 void mem_cgroup_split_huge_fixup(struct page *head)
3470 struct page_cgroup *head_pc = lookup_page_cgroup(head);
3471 struct page_cgroup *pc;
3472 struct mem_cgroup *memcg;
3475 if (mem_cgroup_disabled())
3478 memcg = head_pc->mem_cgroup;
3479 for (i = 1; i < HPAGE_PMD_NR; i++) {
3481 pc->mem_cgroup = memcg;
3482 smp_wmb();/* see __commit_charge() */
3483 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3485 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3488 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3491 * mem_cgroup_move_account - move account of the page
3493 * @nr_pages: number of regular pages (>1 for huge pages)
3494 * @pc: page_cgroup of the page.
3495 * @from: mem_cgroup which the page is moved from.
3496 * @to: mem_cgroup which the page is moved to. @from != @to.
3498 * The caller must confirm following.
3499 * - page is not on LRU (isolate_page() is useful.)
3500 * - compound_lock is held when nr_pages > 1
3502 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3505 static int mem_cgroup_move_account(struct page *page,
3506 unsigned int nr_pages,
3507 struct page_cgroup *pc,
3508 struct mem_cgroup *from,
3509 struct mem_cgroup *to)
3511 unsigned long flags;
3513 bool anon = PageAnon(page);
3515 VM_BUG_ON(from == to);
3516 VM_BUG_ON(PageLRU(page));
3518 * The page is isolated from LRU. So, collapse function
3519 * will not handle this page. But page splitting can happen.
3520 * Do this check under compound_page_lock(). The caller should
3524 if (nr_pages > 1 && !PageTransHuge(page))
3527 lock_page_cgroup(pc);
3530 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3533 move_lock_mem_cgroup(from, &flags);
3535 if (!anon && page_mapped(page)) {
3536 /* Update mapped_file data for mem_cgroup */
3538 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3539 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3542 mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
3544 /* caller should have done css_get */
3545 pc->mem_cgroup = to;
3546 mem_cgroup_charge_statistics(to, page, anon, nr_pages);
3547 move_unlock_mem_cgroup(from, &flags);
3550 unlock_page_cgroup(pc);
3554 memcg_check_events(to, page);
3555 memcg_check_events(from, page);
3561 * mem_cgroup_move_parent - moves page to the parent group
3562 * @page: the page to move
3563 * @pc: page_cgroup of the page
3564 * @child: page's cgroup
3566 * move charges to its parent or the root cgroup if the group has no
3567 * parent (aka use_hierarchy==0).
3568 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3569 * mem_cgroup_move_account fails) the failure is always temporary and
3570 * it signals a race with a page removal/uncharge or migration. In the
3571 * first case the page is on the way out and it will vanish from the LRU
3572 * on the next attempt and the call should be retried later.
3573 * Isolation from the LRU fails only if page has been isolated from
3574 * the LRU since we looked at it and that usually means either global
3575 * reclaim or migration going on. The page will either get back to the
3577 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3578 * (!PageCgroupUsed) or moved to a different group. The page will
3579 * disappear in the next attempt.
3581 static int mem_cgroup_move_parent(struct page *page,
3582 struct page_cgroup *pc,
3583 struct mem_cgroup *child)
3585 struct mem_cgroup *parent;
3586 unsigned int nr_pages;
3587 unsigned long uninitialized_var(flags);
3590 VM_BUG_ON(mem_cgroup_is_root(child));
3593 if (!get_page_unless_zero(page))
3595 if (isolate_lru_page(page))
3598 nr_pages = hpage_nr_pages(page);
3600 parent = parent_mem_cgroup(child);
3602 * If no parent, move charges to root cgroup.
3605 parent = root_mem_cgroup;
3608 VM_BUG_ON(!PageTransHuge(page));
3609 flags = compound_lock_irqsave(page);
3612 ret = mem_cgroup_move_account(page, nr_pages,
3615 __mem_cgroup_cancel_local_charge(child, nr_pages);
3618 compound_unlock_irqrestore(page, flags);
3619 putback_lru_page(page);
3627 * Charge the memory controller for page usage.
3629 * 0 if the charge was successful
3630 * < 0 if the cgroup is over its limit
3632 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
3633 gfp_t gfp_mask, enum charge_type ctype)
3635 struct mem_cgroup *memcg = NULL;
3636 unsigned int nr_pages = 1;
3640 if (PageTransHuge(page)) {
3641 nr_pages <<= compound_order(page);
3642 VM_BUG_ON(!PageTransHuge(page));
3644 * Never OOM-kill a process for a huge page. The
3645 * fault handler will fall back to regular pages.
3650 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
3653 __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
3657 int mem_cgroup_newpage_charge(struct page *page,
3658 struct mm_struct *mm, gfp_t gfp_mask)
3660 if (mem_cgroup_disabled())
3662 VM_BUG_ON(page_mapped(page));
3663 VM_BUG_ON(page->mapping && !PageAnon(page));
3665 return mem_cgroup_charge_common(page, mm, gfp_mask,
3666 MEM_CGROUP_CHARGE_TYPE_ANON);
3670 * While swap-in, try_charge -> commit or cancel, the page is locked.
3671 * And when try_charge() successfully returns, one refcnt to memcg without
3672 * struct page_cgroup is acquired. This refcnt will be consumed by
3673 * "commit()" or removed by "cancel()"
3675 static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3678 struct mem_cgroup **memcgp)
3680 struct mem_cgroup *memcg;
3681 struct page_cgroup *pc;
3684 pc = lookup_page_cgroup(page);
3686 * Every swap fault against a single page tries to charge the
3687 * page, bail as early as possible. shmem_unuse() encounters
3688 * already charged pages, too. The USED bit is protected by
3689 * the page lock, which serializes swap cache removal, which
3690 * in turn serializes uncharging.
3692 if (PageCgroupUsed(pc))
3694 if (!do_swap_account)
3696 memcg = try_get_mem_cgroup_from_page(page);
3700 ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
3701 css_put(&memcg->css);
3706 ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
3712 int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3713 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3716 if (mem_cgroup_disabled())
3719 * A racing thread's fault, or swapoff, may have already
3720 * updated the pte, and even removed page from swap cache: in
3721 * those cases unuse_pte()'s pte_same() test will fail; but
3722 * there's also a KSM case which does need to charge the page.
3724 if (!PageSwapCache(page)) {
3727 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true);
3732 return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3735 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3737 if (mem_cgroup_disabled())
3741 __mem_cgroup_cancel_charge(memcg, 1);
3745 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
3746 enum charge_type ctype)
3748 if (mem_cgroup_disabled())
3753 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
3755 * Now swap is on-memory. This means this page may be
3756 * counted both as mem and swap....double count.
3757 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3758 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3759 * may call delete_from_swap_cache() before reach here.
3761 if (do_swap_account && PageSwapCache(page)) {
3762 swp_entry_t ent = {.val = page_private(page)};
3763 mem_cgroup_uncharge_swap(ent);
3767 void mem_cgroup_commit_charge_swapin(struct page *page,
3768 struct mem_cgroup *memcg)
3770 __mem_cgroup_commit_charge_swapin(page, memcg,
3771 MEM_CGROUP_CHARGE_TYPE_ANON);
3774 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
3777 struct mem_cgroup *memcg = NULL;
3778 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3781 if (mem_cgroup_disabled())
3783 if (PageCompound(page))
3786 if (!PageSwapCache(page))
3787 ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
3788 else { /* page is swapcache/shmem */
3789 ret = __mem_cgroup_try_charge_swapin(mm, page,
3792 __mem_cgroup_commit_charge_swapin(page, memcg, type);
3797 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
3798 unsigned int nr_pages,
3799 const enum charge_type ctype)
3801 struct memcg_batch_info *batch = NULL;
3802 bool uncharge_memsw = true;
3804 /* If swapout, usage of swap doesn't decrease */
3805 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3806 uncharge_memsw = false;
3808 batch = ¤t->memcg_batch;
3810 * In usual, we do css_get() when we remember memcg pointer.
3811 * But in this case, we keep res->usage until end of a series of
3812 * uncharges. Then, it's ok to ignore memcg's refcnt.
3815 batch->memcg = memcg;
3817 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3818 * In those cases, all pages freed continuously can be expected to be in
3819 * the same cgroup and we have chance to coalesce uncharges.
3820 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3821 * because we want to do uncharge as soon as possible.
3824 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
3825 goto direct_uncharge;
3828 goto direct_uncharge;
3831 * In typical case, batch->memcg == mem. This means we can
3832 * merge a series of uncharges to an uncharge of res_counter.
3833 * If not, we uncharge res_counter ony by one.
3835 if (batch->memcg != memcg)
3836 goto direct_uncharge;
3837 /* remember freed charge and uncharge it later */
3840 batch->memsw_nr_pages++;
3843 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
3845 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
3846 if (unlikely(batch->memcg != memcg))
3847 memcg_oom_recover(memcg);
3851 * uncharge if !page_mapped(page)
3853 static struct mem_cgroup *
3854 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
3857 struct mem_cgroup *memcg = NULL;
3858 unsigned int nr_pages = 1;
3859 struct page_cgroup *pc;
3862 if (mem_cgroup_disabled())
3865 if (PageTransHuge(page)) {
3866 nr_pages <<= compound_order(page);
3867 VM_BUG_ON(!PageTransHuge(page));
3870 * Check if our page_cgroup is valid
3872 pc = lookup_page_cgroup(page);
3873 if (unlikely(!PageCgroupUsed(pc)))
3876 lock_page_cgroup(pc);
3878 memcg = pc->mem_cgroup;
3880 if (!PageCgroupUsed(pc))
3883 anon = PageAnon(page);
3886 case MEM_CGROUP_CHARGE_TYPE_ANON:
3888 * Generally PageAnon tells if it's the anon statistics to be
3889 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3890 * used before page reached the stage of being marked PageAnon.
3894 case MEM_CGROUP_CHARGE_TYPE_DROP:
3895 /* See mem_cgroup_prepare_migration() */
3896 if (page_mapped(page))
3899 * Pages under migration may not be uncharged. But
3900 * end_migration() /must/ be the one uncharging the
3901 * unused post-migration page and so it has to call
3902 * here with the migration bit still set. See the
3903 * res_counter handling below.
3905 if (!end_migration && PageCgroupMigration(pc))
3908 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3909 if (!PageAnon(page)) { /* Shared memory */
3910 if (page->mapping && !page_is_file_cache(page))
3912 } else if (page_mapped(page)) /* Anon */
3919 mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
3921 ClearPageCgroupUsed(pc);
3923 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3924 * freed from LRU. This is safe because uncharged page is expected not
3925 * to be reused (freed soon). Exception is SwapCache, it's handled by
3926 * special functions.
3929 unlock_page_cgroup(pc);
3931 * even after unlock, we have memcg->res.usage here and this memcg
3932 * will never be freed, so it's safe to call css_get().
3934 memcg_check_events(memcg, page);
3935 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3936 mem_cgroup_swap_statistics(memcg, true);
3937 css_get(&memcg->css);
3940 * Migration does not charge the res_counter for the
3941 * replacement page, so leave it alone when phasing out the
3942 * page that is unused after the migration.
3944 if (!end_migration && !mem_cgroup_is_root(memcg))
3945 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
3950 unlock_page_cgroup(pc);
3954 void mem_cgroup_uncharge_page(struct page *page)
3957 if (page_mapped(page))
3959 VM_BUG_ON(page->mapping && !PageAnon(page));
3961 * If the page is in swap cache, uncharge should be deferred
3962 * to the swap path, which also properly accounts swap usage
3963 * and handles memcg lifetime.
3965 * Note that this check is not stable and reclaim may add the
3966 * page to swap cache at any time after this. However, if the
3967 * page is not in swap cache by the time page->mapcount hits
3968 * 0, there won't be any page table references to the swap
3969 * slot, and reclaim will free it and not actually write the
3972 if (PageSwapCache(page))
3974 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
3977 void mem_cgroup_uncharge_cache_page(struct page *page)
3979 VM_BUG_ON(page_mapped(page));
3980 VM_BUG_ON(page->mapping);
3981 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
3985 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3986 * In that cases, pages are freed continuously and we can expect pages
3987 * are in the same memcg. All these calls itself limits the number of
3988 * pages freed at once, then uncharge_start/end() is called properly.
3989 * This may be called prural(2) times in a context,
3992 void mem_cgroup_uncharge_start(void)
3994 current->memcg_batch.do_batch++;
3995 /* We can do nest. */
3996 if (current->memcg_batch.do_batch == 1) {
3997 current->memcg_batch.memcg = NULL;
3998 current->memcg_batch.nr_pages = 0;
3999 current->memcg_batch.memsw_nr_pages = 0;
4003 void mem_cgroup_uncharge_end(void)
4005 struct memcg_batch_info *batch = ¤t->memcg_batch;
4007 if (!batch->do_batch)
4011 if (batch->do_batch) /* If stacked, do nothing. */
4017 * This "batch->memcg" is valid without any css_get/put etc...
4018 * bacause we hide charges behind us.
4020 if (batch->nr_pages)
4021 res_counter_uncharge(&batch->memcg->res,
4022 batch->nr_pages * PAGE_SIZE);
4023 if (batch->memsw_nr_pages)
4024 res_counter_uncharge(&batch->memcg->memsw,
4025 batch->memsw_nr_pages * PAGE_SIZE);
4026 memcg_oom_recover(batch->memcg);
4027 /* forget this pointer (for sanity check) */
4028 batch->memcg = NULL;
4033 * called after __delete_from_swap_cache() and drop "page" account.
4034 * memcg information is recorded to swap_cgroup of "ent"
4037 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
4039 struct mem_cgroup *memcg;
4040 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4042 if (!swapout) /* this was a swap cache but the swap is unused ! */
4043 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4045 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
4048 * record memcg information, if swapout && memcg != NULL,
4049 * css_get() was called in uncharge().
4051 if (do_swap_account && swapout && memcg)
4052 swap_cgroup_record(ent, css_id(&memcg->css));
4056 #ifdef CONFIG_MEMCG_SWAP
4058 * called from swap_entry_free(). remove record in swap_cgroup and
4059 * uncharge "memsw" account.
4061 void mem_cgroup_uncharge_swap(swp_entry_t ent)
4063 struct mem_cgroup *memcg;
4066 if (!do_swap_account)
4069 id = swap_cgroup_record(ent, 0);
4071 memcg = mem_cgroup_lookup(id);
4074 * We uncharge this because swap is freed.
4075 * This memcg can be obsolete one. We avoid calling css_tryget
4077 if (!mem_cgroup_is_root(memcg))
4078 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
4079 mem_cgroup_swap_statistics(memcg, false);
4080 css_put(&memcg->css);
4086 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4087 * @entry: swap entry to be moved
4088 * @from: mem_cgroup which the entry is moved from
4089 * @to: mem_cgroup which the entry is moved to
4091 * It succeeds only when the swap_cgroup's record for this entry is the same
4092 * as the mem_cgroup's id of @from.
4094 * Returns 0 on success, -EINVAL on failure.
4096 * The caller must have charged to @to, IOW, called res_counter_charge() about
4097 * both res and memsw, and called css_get().
4099 static int mem_cgroup_move_swap_account(swp_entry_t entry,
4100 struct mem_cgroup *from, struct mem_cgroup *to)
4102 unsigned short old_id, new_id;
4104 old_id = css_id(&from->css);
4105 new_id = css_id(&to->css);
4107 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
4108 mem_cgroup_swap_statistics(from, false);
4109 mem_cgroup_swap_statistics(to, true);
4111 * This function is only called from task migration context now.
4112 * It postpones res_counter and refcount handling till the end
4113 * of task migration(mem_cgroup_clear_mc()) for performance
4114 * improvement. But we cannot postpone css_get(to) because if
4115 * the process that has been moved to @to does swap-in, the
4116 * refcount of @to might be decreased to 0.
4118 * We are in attach() phase, so the cgroup is guaranteed to be
4119 * alive, so we can just call css_get().
4127 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
4128 struct mem_cgroup *from, struct mem_cgroup *to)
4135 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4138 void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4139 struct mem_cgroup **memcgp)
4141 struct mem_cgroup *memcg = NULL;
4142 unsigned int nr_pages = 1;
4143 struct page_cgroup *pc;
4144 enum charge_type ctype;
4148 if (mem_cgroup_disabled())
4151 if (PageTransHuge(page))
4152 nr_pages <<= compound_order(page);
4154 pc = lookup_page_cgroup(page);
4155 lock_page_cgroup(pc);
4156 if (PageCgroupUsed(pc)) {
4157 memcg = pc->mem_cgroup;
4158 css_get(&memcg->css);
4160 * At migrating an anonymous page, its mapcount goes down
4161 * to 0 and uncharge() will be called. But, even if it's fully
4162 * unmapped, migration may fail and this page has to be
4163 * charged again. We set MIGRATION flag here and delay uncharge
4164 * until end_migration() is called
4166 * Corner Case Thinking
4168 * When the old page was mapped as Anon and it's unmap-and-freed
4169 * while migration was ongoing.
4170 * If unmap finds the old page, uncharge() of it will be delayed
4171 * until end_migration(). If unmap finds a new page, it's
4172 * uncharged when it make mapcount to be 1->0. If unmap code
4173 * finds swap_migration_entry, the new page will not be mapped
4174 * and end_migration() will find it(mapcount==0).
4177 * When the old page was mapped but migraion fails, the kernel
4178 * remaps it. A charge for it is kept by MIGRATION flag even
4179 * if mapcount goes down to 0. We can do remap successfully
4180 * without charging it again.
4183 * The "old" page is under lock_page() until the end of
4184 * migration, so, the old page itself will not be swapped-out.
4185 * If the new page is swapped out before end_migraton, our
4186 * hook to usual swap-out path will catch the event.
4189 SetPageCgroupMigration(pc);
4191 unlock_page_cgroup(pc);
4193 * If the page is not charged at this point,
4201 * We charge new page before it's used/mapped. So, even if unlock_page()
4202 * is called before end_migration, we can catch all events on this new
4203 * page. In the case new page is migrated but not remapped, new page's
4204 * mapcount will be finally 0 and we call uncharge in end_migration().
4207 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
4209 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
4211 * The page is committed to the memcg, but it's not actually
4212 * charged to the res_counter since we plan on replacing the
4213 * old one and only one page is going to be left afterwards.
4215 __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
4218 /* remove redundant charge if migration failed*/
4219 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
4220 struct page *oldpage, struct page *newpage, bool migration_ok)
4222 struct page *used, *unused;
4223 struct page_cgroup *pc;
4229 if (!migration_ok) {
4236 anon = PageAnon(used);
4237 __mem_cgroup_uncharge_common(unused,
4238 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4239 : MEM_CGROUP_CHARGE_TYPE_CACHE,
4241 css_put(&memcg->css);
4243 * We disallowed uncharge of pages under migration because mapcount
4244 * of the page goes down to zero, temporarly.
4245 * Clear the flag and check the page should be charged.
4247 pc = lookup_page_cgroup(oldpage);
4248 lock_page_cgroup(pc);
4249 ClearPageCgroupMigration(pc);
4250 unlock_page_cgroup(pc);
4253 * If a page is a file cache, radix-tree replacement is very atomic
4254 * and we can skip this check. When it was an Anon page, its mapcount
4255 * goes down to 0. But because we added MIGRATION flage, it's not
4256 * uncharged yet. There are several case but page->mapcount check
4257 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4258 * check. (see prepare_charge() also)
4261 mem_cgroup_uncharge_page(used);
4265 * At replace page cache, newpage is not under any memcg but it's on
4266 * LRU. So, this function doesn't touch res_counter but handles LRU
4267 * in correct way. Both pages are locked so we cannot race with uncharge.
4269 void mem_cgroup_replace_page_cache(struct page *oldpage,
4270 struct page *newpage)
4272 struct mem_cgroup *memcg = NULL;
4273 struct page_cgroup *pc;
4274 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
4276 if (mem_cgroup_disabled())
4279 pc = lookup_page_cgroup(oldpage);
4280 /* fix accounting on old pages */
4281 lock_page_cgroup(pc);
4282 if (PageCgroupUsed(pc)) {
4283 memcg = pc->mem_cgroup;
4284 mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
4285 ClearPageCgroupUsed(pc);
4287 unlock_page_cgroup(pc);
4290 * When called from shmem_replace_page(), in some cases the
4291 * oldpage has already been charged, and in some cases not.
4296 * Even if newpage->mapping was NULL before starting replacement,
4297 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4298 * LRU while we overwrite pc->mem_cgroup.
4300 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
4303 #ifdef CONFIG_DEBUG_VM
4304 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4306 struct page_cgroup *pc;
4308 pc = lookup_page_cgroup(page);
4310 * Can be NULL while feeding pages into the page allocator for
4311 * the first time, i.e. during boot or memory hotplug;
4312 * or when mem_cgroup_disabled().
4314 if (likely(pc) && PageCgroupUsed(pc))
4319 bool mem_cgroup_bad_page_check(struct page *page)
4321 if (mem_cgroup_disabled())
4324 return lookup_page_cgroup_used(page) != NULL;
4327 void mem_cgroup_print_bad_page(struct page *page)
4329 struct page_cgroup *pc;
4331 pc = lookup_page_cgroup_used(page);
4333 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4334 pc, pc->flags, pc->mem_cgroup);
4339 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
4340 unsigned long long val)
4343 u64 memswlimit, memlimit;
4345 int children = mem_cgroup_count_children(memcg);
4346 u64 curusage, oldusage;
4350 * For keeping hierarchical_reclaim simple, how long we should retry
4351 * is depends on callers. We set our retry-count to be function
4352 * of # of children which we should visit in this loop.
4354 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4356 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4359 while (retry_count) {
4360 if (signal_pending(current)) {
4365 * Rather than hide all in some function, I do this in
4366 * open coded manner. You see what this really does.
4367 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4369 mutex_lock(&set_limit_mutex);
4370 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4371 if (memswlimit < val) {
4373 mutex_unlock(&set_limit_mutex);
4377 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4381 ret = res_counter_set_limit(&memcg->res, val);
4383 if (memswlimit == val)
4384 memcg->memsw_is_minimum = true;
4386 memcg->memsw_is_minimum = false;
4388 mutex_unlock(&set_limit_mutex);
4393 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4394 MEM_CGROUP_RECLAIM_SHRINK);
4395 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4396 /* Usage is reduced ? */
4397 if (curusage >= oldusage)
4400 oldusage = curusage;
4402 if (!ret && enlarge)
4403 memcg_oom_recover(memcg);
4408 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4409 unsigned long long val)
4412 u64 memlimit, memswlimit, oldusage, curusage;
4413 int children = mem_cgroup_count_children(memcg);
4417 /* see mem_cgroup_resize_res_limit */
4418 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
4419 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4420 while (retry_count) {
4421 if (signal_pending(current)) {
4426 * Rather than hide all in some function, I do this in
4427 * open coded manner. You see what this really does.
4428 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4430 mutex_lock(&set_limit_mutex);
4431 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4432 if (memlimit > val) {
4434 mutex_unlock(&set_limit_mutex);
4437 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4438 if (memswlimit < val)
4440 ret = res_counter_set_limit(&memcg->memsw, val);
4442 if (memlimit == val)
4443 memcg->memsw_is_minimum = true;
4445 memcg->memsw_is_minimum = false;
4447 mutex_unlock(&set_limit_mutex);
4452 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4453 MEM_CGROUP_RECLAIM_NOSWAP |
4454 MEM_CGROUP_RECLAIM_SHRINK);
4455 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4456 /* Usage is reduced ? */
4457 if (curusage >= oldusage)
4460 oldusage = curusage;
4462 if (!ret && enlarge)
4463 memcg_oom_recover(memcg);
4468 * mem_cgroup_force_empty_list - clears LRU of a group
4469 * @memcg: group to clear
4472 * @lru: lru to to clear
4474 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4475 * reclaim the pages page themselves - pages are moved to the parent (or root)
4478 static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
4479 int node, int zid, enum lru_list lru)
4481 struct lruvec *lruvec;
4482 unsigned long flags;
4483 struct list_head *list;
4487 zone = &NODE_DATA(node)->node_zones[zid];
4488 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4489 list = &lruvec->lists[lru];
4493 struct page_cgroup *pc;
4496 spin_lock_irqsave(&zone->lru_lock, flags);
4497 if (list_empty(list)) {
4498 spin_unlock_irqrestore(&zone->lru_lock, flags);
4501 page = list_entry(list->prev, struct page, lru);
4503 list_move(&page->lru, list);
4505 spin_unlock_irqrestore(&zone->lru_lock, flags);
4508 spin_unlock_irqrestore(&zone->lru_lock, flags);
4510 pc = lookup_page_cgroup(page);
4512 if (mem_cgroup_move_parent(page, pc, memcg)) {
4513 /* found lock contention or "pc" is obsolete. */
4518 } while (!list_empty(list));
4522 * make mem_cgroup's charge to be 0 if there is no task by moving
4523 * all the charges and pages to the parent.
4524 * This enables deleting this mem_cgroup.
4526 * Caller is responsible for holding css reference on the memcg.
4528 static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
4534 /* This is for making all *used* pages to be on LRU. */
4535 lru_add_drain_all();
4536 drain_all_stock_sync(memcg);
4537 mem_cgroup_start_move(memcg);
4538 for_each_node_state(node, N_MEMORY) {
4539 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4542 mem_cgroup_force_empty_list(memcg,
4547 mem_cgroup_end_move(memcg);
4548 memcg_oom_recover(memcg);
4552 * Kernel memory may not necessarily be trackable to a specific
4553 * process. So they are not migrated, and therefore we can't
4554 * expect their value to drop to 0 here.
4555 * Having res filled up with kmem only is enough.
4557 * This is a safety check because mem_cgroup_force_empty_list
4558 * could have raced with mem_cgroup_replace_page_cache callers
4559 * so the lru seemed empty but the page could have been added
4560 * right after the check. RES_USAGE should be safe as we always
4561 * charge before adding to the LRU.
4563 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4564 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4565 } while (usage > 0);
4569 * This mainly exists for tests during the setting of set of use_hierarchy.
4570 * Since this is the very setting we are changing, the current hierarchy value
4573 static inline bool __memcg_has_children(struct mem_cgroup *memcg)
4575 struct cgroup_subsys_state *pos;
4577 /* bounce at first found */
4578 css_for_each_child(pos, &memcg->css)
4584 * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed
4585 * to be already dead (as in mem_cgroup_force_empty, for instance). This is
4586 * from mem_cgroup_count_children(), in the sense that we don't really care how
4587 * many children we have; we only need to know if we have any. It also counts
4588 * any memcg without hierarchy as infertile.
4590 static inline bool memcg_has_children(struct mem_cgroup *memcg)
4592 return memcg->use_hierarchy && __memcg_has_children(memcg);
4596 * Reclaims as many pages from the given memcg as possible and moves
4597 * the rest to the parent.
4599 * Caller is responsible for holding css reference for memcg.
4601 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4603 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4604 struct cgroup *cgrp = memcg->css.cgroup;
4606 /* returns EBUSY if there is a task or if we come here twice. */
4607 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
4610 /* we call try-to-free pages for make this cgroup empty */
4611 lru_add_drain_all();
4612 /* try to free all pages in this cgroup */
4613 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4616 if (signal_pending(current))
4619 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4623 /* maybe some writeback is necessary */
4624 congestion_wait(BLK_RW_ASYNC, HZ/10);
4629 mem_cgroup_reparent_charges(memcg);
4634 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css,
4637 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4639 if (mem_cgroup_is_root(memcg))
4641 return mem_cgroup_force_empty(memcg);
4644 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4647 return mem_cgroup_from_css(css)->use_hierarchy;
4650 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4651 struct cftype *cft, u64 val)
4654 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4655 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css));
4657 mutex_lock(&memcg_create_mutex);
4659 if (memcg->use_hierarchy == val)
4663 * If parent's use_hierarchy is set, we can't make any modifications
4664 * in the child subtrees. If it is unset, then the change can
4665 * occur, provided the current cgroup has no children.
4667 * For the root cgroup, parent_mem is NULL, we allow value to be
4668 * set if there are no children.
4670 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4671 (val == 1 || val == 0)) {
4672 if (!__memcg_has_children(memcg))
4673 memcg->use_hierarchy = val;
4680 mutex_unlock(&memcg_create_mutex);
4686 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
4687 enum mem_cgroup_stat_index idx)
4689 struct mem_cgroup *iter;
4692 /* Per-cpu values can be negative, use a signed accumulator */
4693 for_each_mem_cgroup_tree(iter, memcg)
4694 val += mem_cgroup_read_stat(iter, idx);
4696 if (val < 0) /* race ? */
4701 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
4705 if (!mem_cgroup_is_root(memcg)) {
4707 return res_counter_read_u64(&memcg->res, RES_USAGE);
4709 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
4713 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4714 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4716 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4717 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
4720 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
4722 return val << PAGE_SHIFT;
4725 static ssize_t mem_cgroup_read(struct cgroup_subsys_state *css,
4726 struct cftype *cft, struct file *file,
4727 char __user *buf, size_t nbytes, loff_t *ppos)
4729 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4735 type = MEMFILE_TYPE(cft->private);
4736 name = MEMFILE_ATTR(cft->private);
4740 if (name == RES_USAGE)
4741 val = mem_cgroup_usage(memcg, false);
4743 val = res_counter_read_u64(&memcg->res, name);
4746 if (name == RES_USAGE)
4747 val = mem_cgroup_usage(memcg, true);
4749 val = res_counter_read_u64(&memcg->memsw, name);
4752 val = res_counter_read_u64(&memcg->kmem, name);
4758 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
4759 return simple_read_from_buffer(buf, nbytes, ppos, str, len);
4762 static int memcg_update_kmem_limit(struct cgroup_subsys_state *css, u64 val)
4765 #ifdef CONFIG_MEMCG_KMEM
4766 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4768 * For simplicity, we won't allow this to be disabled. It also can't
4769 * be changed if the cgroup has children already, or if tasks had
4772 * If tasks join before we set the limit, a person looking at
4773 * kmem.usage_in_bytes will have no way to determine when it took
4774 * place, which makes the value quite meaningless.
4776 * After it first became limited, changes in the value of the limit are
4777 * of course permitted.
4779 mutex_lock(&memcg_create_mutex);
4780 mutex_lock(&set_limit_mutex);
4781 if (!memcg->kmem_account_flags && val != RESOURCE_MAX) {
4782 if (cgroup_task_count(css->cgroup) || memcg_has_children(memcg)) {
4786 ret = res_counter_set_limit(&memcg->kmem, val);
4789 ret = memcg_update_cache_sizes(memcg);
4791 res_counter_set_limit(&memcg->kmem, RESOURCE_MAX);
4794 static_key_slow_inc(&memcg_kmem_enabled_key);
4796 * setting the active bit after the inc will guarantee no one
4797 * starts accounting before all call sites are patched
4799 memcg_kmem_set_active(memcg);
4801 ret = res_counter_set_limit(&memcg->kmem, val);
4803 mutex_unlock(&set_limit_mutex);
4804 mutex_unlock(&memcg_create_mutex);
4809 #ifdef CONFIG_MEMCG_KMEM
4810 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
4813 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4817 memcg->kmem_account_flags = parent->kmem_account_flags;
4819 * When that happen, we need to disable the static branch only on those
4820 * memcgs that enabled it. To achieve this, we would be forced to
4821 * complicate the code by keeping track of which memcgs were the ones
4822 * that actually enabled limits, and which ones got it from its
4825 * It is a lot simpler just to do static_key_slow_inc() on every child
4826 * that is accounted.
4828 if (!memcg_kmem_is_active(memcg))
4832 * __mem_cgroup_free() will issue static_key_slow_dec() because this
4833 * memcg is active already. If the later initialization fails then the
4834 * cgroup core triggers the cleanup so we do not have to do it here.
4836 static_key_slow_inc(&memcg_kmem_enabled_key);
4838 mutex_lock(&set_limit_mutex);
4839 memcg_stop_kmem_account();
4840 ret = memcg_update_cache_sizes(memcg);
4841 memcg_resume_kmem_account();
4842 mutex_unlock(&set_limit_mutex);
4846 #endif /* CONFIG_MEMCG_KMEM */
4849 * The user of this function is...
4852 static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
4855 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4858 unsigned long long val;
4861 type = MEMFILE_TYPE(cft->private);
4862 name = MEMFILE_ATTR(cft->private);
4866 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
4870 /* This function does all necessary parse...reuse it */
4871 ret = res_counter_memparse_write_strategy(buffer, &val);
4875 ret = mem_cgroup_resize_limit(memcg, val);
4876 else if (type == _MEMSWAP)
4877 ret = mem_cgroup_resize_memsw_limit(memcg, val);
4878 else if (type == _KMEM)
4879 ret = memcg_update_kmem_limit(css, val);
4883 case RES_SOFT_LIMIT:
4884 ret = res_counter_memparse_write_strategy(buffer, &val);
4888 * For memsw, soft limits are hard to implement in terms
4889 * of semantics, for now, we support soft limits for
4890 * control without swap
4893 ret = res_counter_set_soft_limit(&memcg->res, val);
4898 ret = -EINVAL; /* should be BUG() ? */
4904 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
4905 unsigned long long *mem_limit, unsigned long long *memsw_limit)
4907 unsigned long long min_limit, min_memsw_limit, tmp;
4909 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4910 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4911 if (!memcg->use_hierarchy)
4914 while (css_parent(&memcg->css)) {
4915 memcg = mem_cgroup_from_css(css_parent(&memcg->css));
4916 if (!memcg->use_hierarchy)
4918 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
4919 min_limit = min(min_limit, tmp);
4920 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4921 min_memsw_limit = min(min_memsw_limit, tmp);
4924 *mem_limit = min_limit;
4925 *memsw_limit = min_memsw_limit;
4928 static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
4930 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4934 type = MEMFILE_TYPE(event);
4935 name = MEMFILE_ATTR(event);
4940 res_counter_reset_max(&memcg->res);
4941 else if (type == _MEMSWAP)
4942 res_counter_reset_max(&memcg->memsw);
4943 else if (type == _KMEM)
4944 res_counter_reset_max(&memcg->kmem);
4950 res_counter_reset_failcnt(&memcg->res);
4951 else if (type == _MEMSWAP)
4952 res_counter_reset_failcnt(&memcg->memsw);
4953 else if (type == _KMEM)
4954 res_counter_reset_failcnt(&memcg->kmem);
4963 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
4966 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
4970 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4971 struct cftype *cft, u64 val)
4973 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4975 if (val >= (1 << NR_MOVE_TYPE))
4979 * No kind of locking is needed in here, because ->can_attach() will
4980 * check this value once in the beginning of the process, and then carry
4981 * on with stale data. This means that changes to this value will only
4982 * affect task migrations starting after the change.
4984 memcg->move_charge_at_immigrate = val;
4988 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4989 struct cftype *cft, u64 val)
4996 static int memcg_numa_stat_show(struct cgroup_subsys_state *css,
4997 struct cftype *cft, struct seq_file *m)
5000 unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
5001 unsigned long node_nr;
5002 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5004 total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL);
5005 seq_printf(m, "total=%lu", total_nr);
5006 for_each_node_state(nid, N_MEMORY) {
5007 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL);
5008 seq_printf(m, " N%d=%lu", nid, node_nr);
5012 file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE);
5013 seq_printf(m, "file=%lu", file_nr);
5014 for_each_node_state(nid, N_MEMORY) {
5015 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5017 seq_printf(m, " N%d=%lu", nid, node_nr);
5021 anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON);
5022 seq_printf(m, "anon=%lu", anon_nr);
5023 for_each_node_state(nid, N_MEMORY) {
5024 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5026 seq_printf(m, " N%d=%lu", nid, node_nr);
5030 unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
5031 seq_printf(m, "unevictable=%lu", unevictable_nr);
5032 for_each_node_state(nid, N_MEMORY) {
5033 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5034 BIT(LRU_UNEVICTABLE));
5035 seq_printf(m, " N%d=%lu", nid, node_nr);
5040 #endif /* CONFIG_NUMA */
5042 static inline void mem_cgroup_lru_names_not_uptodate(void)
5044 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5047 static int memcg_stat_show(struct cgroup_subsys_state *css, struct cftype *cft,
5050 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5051 struct mem_cgroup *mi;
5054 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5055 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5057 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5058 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
5061 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5062 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5063 mem_cgroup_read_events(memcg, i));
5065 for (i = 0; i < NR_LRU_LISTS; i++)
5066 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5067 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5069 /* Hierarchical information */
5071 unsigned long long limit, memsw_limit;
5072 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
5073 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
5074 if (do_swap_account)
5075 seq_printf(m, "hierarchical_memsw_limit %llu\n",
5079 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5082 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5084 for_each_mem_cgroup_tree(mi, memcg)
5085 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5086 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5089 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5090 unsigned long long val = 0;
5092 for_each_mem_cgroup_tree(mi, memcg)
5093 val += mem_cgroup_read_events(mi, i);
5094 seq_printf(m, "total_%s %llu\n",
5095 mem_cgroup_events_names[i], val);
5098 for (i = 0; i < NR_LRU_LISTS; i++) {
5099 unsigned long long val = 0;
5101 for_each_mem_cgroup_tree(mi, memcg)
5102 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5103 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
5106 #ifdef CONFIG_DEBUG_VM
5109 struct mem_cgroup_per_zone *mz;
5110 struct zone_reclaim_stat *rstat;
5111 unsigned long recent_rotated[2] = {0, 0};
5112 unsigned long recent_scanned[2] = {0, 0};
5114 for_each_online_node(nid)
5115 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
5116 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
5117 rstat = &mz->lruvec.reclaim_stat;
5119 recent_rotated[0] += rstat->recent_rotated[0];
5120 recent_rotated[1] += rstat->recent_rotated[1];
5121 recent_scanned[0] += rstat->recent_scanned[0];
5122 recent_scanned[1] += rstat->recent_scanned[1];
5124 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5125 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5126 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5127 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
5134 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
5137 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5139 return mem_cgroup_swappiness(memcg);
5142 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
5143 struct cftype *cft, u64 val)
5145 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5146 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5148 if (val > 100 || !parent)
5151 mutex_lock(&memcg_create_mutex);
5153 /* If under hierarchy, only empty-root can set this value */
5154 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5155 mutex_unlock(&memcg_create_mutex);
5159 memcg->swappiness = val;
5161 mutex_unlock(&memcg_create_mutex);
5166 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5168 struct mem_cgroup_threshold_ary *t;
5174 t = rcu_dereference(memcg->thresholds.primary);
5176 t = rcu_dereference(memcg->memsw_thresholds.primary);
5181 usage = mem_cgroup_usage(memcg, swap);
5184 * current_threshold points to threshold just below or equal to usage.
5185 * If it's not true, a threshold was crossed after last
5186 * call of __mem_cgroup_threshold().
5188 i = t->current_threshold;
5191 * Iterate backward over array of thresholds starting from
5192 * current_threshold and check if a threshold is crossed.
5193 * If none of thresholds below usage is crossed, we read
5194 * only one element of the array here.
5196 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5197 eventfd_signal(t->entries[i].eventfd, 1);
5199 /* i = current_threshold + 1 */
5203 * Iterate forward over array of thresholds starting from
5204 * current_threshold+1 and check if a threshold is crossed.
5205 * If none of thresholds above usage is crossed, we read
5206 * only one element of the array here.
5208 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5209 eventfd_signal(t->entries[i].eventfd, 1);
5211 /* Update current_threshold */
5212 t->current_threshold = i - 1;
5217 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5220 __mem_cgroup_threshold(memcg, false);
5221 if (do_swap_account)
5222 __mem_cgroup_threshold(memcg, true);
5224 memcg = parent_mem_cgroup(memcg);
5228 static int compare_thresholds(const void *a, const void *b)
5230 const struct mem_cgroup_threshold *_a = a;
5231 const struct mem_cgroup_threshold *_b = b;
5233 if (_a->threshold > _b->threshold)
5236 if (_a->threshold < _b->threshold)
5242 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
5244 struct mem_cgroup_eventfd_list *ev;
5246 list_for_each_entry(ev, &memcg->oom_notify, list)
5247 eventfd_signal(ev->eventfd, 1);
5251 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
5253 struct mem_cgroup *iter;
5255 for_each_mem_cgroup_tree(iter, memcg)
5256 mem_cgroup_oom_notify_cb(iter);
5259 static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
5260 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5262 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5263 struct mem_cgroup_thresholds *thresholds;
5264 struct mem_cgroup_threshold_ary *new;
5265 enum res_type type = MEMFILE_TYPE(cft->private);
5266 u64 threshold, usage;
5269 ret = res_counter_memparse_write_strategy(args, &threshold);
5273 mutex_lock(&memcg->thresholds_lock);
5276 thresholds = &memcg->thresholds;
5277 else if (type == _MEMSWAP)
5278 thresholds = &memcg->memsw_thresholds;
5282 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5284 /* Check if a threshold crossed before adding a new one */
5285 if (thresholds->primary)
5286 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5288 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
5290 /* Allocate memory for new array of thresholds */
5291 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
5299 /* Copy thresholds (if any) to new array */
5300 if (thresholds->primary) {
5301 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
5302 sizeof(struct mem_cgroup_threshold));
5305 /* Add new threshold */
5306 new->entries[size - 1].eventfd = eventfd;
5307 new->entries[size - 1].threshold = threshold;
5309 /* Sort thresholds. Registering of new threshold isn't time-critical */
5310 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
5311 compare_thresholds, NULL);
5313 /* Find current threshold */
5314 new->current_threshold = -1;
5315 for (i = 0; i < size; i++) {
5316 if (new->entries[i].threshold <= usage) {
5318 * new->current_threshold will not be used until
5319 * rcu_assign_pointer(), so it's safe to increment
5322 ++new->current_threshold;
5327 /* Free old spare buffer and save old primary buffer as spare */
5328 kfree(thresholds->spare);
5329 thresholds->spare = thresholds->primary;
5331 rcu_assign_pointer(thresholds->primary, new);
5333 /* To be sure that nobody uses thresholds */
5337 mutex_unlock(&memcg->thresholds_lock);
5342 static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
5343 struct cftype *cft, struct eventfd_ctx *eventfd)
5345 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5346 struct mem_cgroup_thresholds *thresholds;
5347 struct mem_cgroup_threshold_ary *new;
5348 enum res_type type = MEMFILE_TYPE(cft->private);
5352 mutex_lock(&memcg->thresholds_lock);
5354 thresholds = &memcg->thresholds;
5355 else if (type == _MEMSWAP)
5356 thresholds = &memcg->memsw_thresholds;
5360 if (!thresholds->primary)
5363 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5365 /* Check if a threshold crossed before removing */
5366 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5368 /* Calculate new number of threshold */
5370 for (i = 0; i < thresholds->primary->size; i++) {
5371 if (thresholds->primary->entries[i].eventfd != eventfd)
5375 new = thresholds->spare;
5377 /* Set thresholds array to NULL if we don't have thresholds */
5386 /* Copy thresholds and find current threshold */
5387 new->current_threshold = -1;
5388 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5389 if (thresholds->primary->entries[i].eventfd == eventfd)
5392 new->entries[j] = thresholds->primary->entries[i];
5393 if (new->entries[j].threshold <= usage) {
5395 * new->current_threshold will not be used
5396 * until rcu_assign_pointer(), so it's safe to increment
5399 ++new->current_threshold;
5405 /* Swap primary and spare array */
5406 thresholds->spare = thresholds->primary;
5407 /* If all events are unregistered, free the spare array */
5409 kfree(thresholds->spare);
5410 thresholds->spare = NULL;
5413 rcu_assign_pointer(thresholds->primary, new);
5415 /* To be sure that nobody uses thresholds */
5418 mutex_unlock(&memcg->thresholds_lock);
5421 static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
5422 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5424 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5425 struct mem_cgroup_eventfd_list *event;
5426 enum res_type type = MEMFILE_TYPE(cft->private);
5428 BUG_ON(type != _OOM_TYPE);
5429 event = kmalloc(sizeof(*event), GFP_KERNEL);
5433 spin_lock(&memcg_oom_lock);
5435 event->eventfd = eventfd;
5436 list_add(&event->list, &memcg->oom_notify);
5438 /* already in OOM ? */
5439 if (atomic_read(&memcg->under_oom))
5440 eventfd_signal(eventfd, 1);
5441 spin_unlock(&memcg_oom_lock);
5446 static void mem_cgroup_oom_unregister_event(struct cgroup_subsys_state *css,
5447 struct cftype *cft, struct eventfd_ctx *eventfd)
5449 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5450 struct mem_cgroup_eventfd_list *ev, *tmp;
5451 enum res_type type = MEMFILE_TYPE(cft->private);
5453 BUG_ON(type != _OOM_TYPE);
5455 spin_lock(&memcg_oom_lock);
5457 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
5458 if (ev->eventfd == eventfd) {
5459 list_del(&ev->list);
5464 spin_unlock(&memcg_oom_lock);
5467 static int mem_cgroup_oom_control_read(struct cgroup_subsys_state *css,
5468 struct cftype *cft, struct cgroup_map_cb *cb)
5470 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5472 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
5474 if (atomic_read(&memcg->under_oom))
5475 cb->fill(cb, "under_oom", 1);
5477 cb->fill(cb, "under_oom", 0);
5481 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
5482 struct cftype *cft, u64 val)
5484 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5485 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5487 /* cannot set to root cgroup and only 0 and 1 are allowed */
5488 if (!parent || !((val == 0) || (val == 1)))
5491 mutex_lock(&memcg_create_mutex);
5492 /* oom-kill-disable is a flag for subhierarchy. */
5493 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5494 mutex_unlock(&memcg_create_mutex);
5497 memcg->oom_kill_disable = val;
5499 memcg_oom_recover(memcg);
5500 mutex_unlock(&memcg_create_mutex);
5504 #ifdef CONFIG_MEMCG_KMEM
5505 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5509 memcg->kmemcg_id = -1;
5510 ret = memcg_propagate_kmem(memcg);
5514 return mem_cgroup_sockets_init(memcg, ss);
5517 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5519 mem_cgroup_sockets_destroy(memcg);
5522 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5524 if (!memcg_kmem_is_active(memcg))
5528 * kmem charges can outlive the cgroup. In the case of slab
5529 * pages, for instance, a page contain objects from various
5530 * processes. As we prevent from taking a reference for every
5531 * such allocation we have to be careful when doing uncharge
5532 * (see memcg_uncharge_kmem) and here during offlining.
5534 * The idea is that that only the _last_ uncharge which sees
5535 * the dead memcg will drop the last reference. An additional
5536 * reference is taken here before the group is marked dead
5537 * which is then paired with css_put during uncharge resp. here.
5539 * Although this might sound strange as this path is called from
5540 * css_offline() when the referencemight have dropped down to 0
5541 * and shouldn't be incremented anymore (css_tryget would fail)
5542 * we do not have other options because of the kmem allocations
5545 css_get(&memcg->css);
5547 memcg_kmem_mark_dead(memcg);
5549 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5552 if (memcg_kmem_test_and_clear_dead(memcg))
5553 css_put(&memcg->css);
5556 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5561 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5565 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5570 static struct cftype mem_cgroup_files[] = {
5572 .name = "usage_in_bytes",
5573 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5574 .read = mem_cgroup_read,
5575 .register_event = mem_cgroup_usage_register_event,
5576 .unregister_event = mem_cgroup_usage_unregister_event,
5579 .name = "max_usage_in_bytes",
5580 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5581 .trigger = mem_cgroup_reset,
5582 .read = mem_cgroup_read,
5585 .name = "limit_in_bytes",
5586 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5587 .write_string = mem_cgroup_write,
5588 .read = mem_cgroup_read,
5591 .name = "soft_limit_in_bytes",
5592 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5593 .write_string = mem_cgroup_write,
5594 .read = mem_cgroup_read,
5598 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5599 .trigger = mem_cgroup_reset,
5600 .read = mem_cgroup_read,
5604 .read_seq_string = memcg_stat_show,
5607 .name = "force_empty",
5608 .trigger = mem_cgroup_force_empty_write,
5611 .name = "use_hierarchy",
5612 .flags = CFTYPE_INSANE,
5613 .write_u64 = mem_cgroup_hierarchy_write,
5614 .read_u64 = mem_cgroup_hierarchy_read,
5617 .name = "swappiness",
5618 .read_u64 = mem_cgroup_swappiness_read,
5619 .write_u64 = mem_cgroup_swappiness_write,
5622 .name = "move_charge_at_immigrate",
5623 .read_u64 = mem_cgroup_move_charge_read,
5624 .write_u64 = mem_cgroup_move_charge_write,
5627 .name = "oom_control",
5628 .read_map = mem_cgroup_oom_control_read,
5629 .write_u64 = mem_cgroup_oom_control_write,
5630 .register_event = mem_cgroup_oom_register_event,
5631 .unregister_event = mem_cgroup_oom_unregister_event,
5632 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
5635 .name = "pressure_level",
5636 .register_event = vmpressure_register_event,
5637 .unregister_event = vmpressure_unregister_event,
5641 .name = "numa_stat",
5642 .read_seq_string = memcg_numa_stat_show,
5645 #ifdef CONFIG_MEMCG_KMEM
5647 .name = "kmem.limit_in_bytes",
5648 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5649 .write_string = mem_cgroup_write,
5650 .read = mem_cgroup_read,
5653 .name = "kmem.usage_in_bytes",
5654 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5655 .read = mem_cgroup_read,
5658 .name = "kmem.failcnt",
5659 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5660 .trigger = mem_cgroup_reset,
5661 .read = mem_cgroup_read,
5664 .name = "kmem.max_usage_in_bytes",
5665 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5666 .trigger = mem_cgroup_reset,
5667 .read = mem_cgroup_read,
5669 #ifdef CONFIG_SLABINFO
5671 .name = "kmem.slabinfo",
5672 .read_seq_string = mem_cgroup_slabinfo_read,
5676 { }, /* terminate */
5679 #ifdef CONFIG_MEMCG_SWAP
5680 static struct cftype memsw_cgroup_files[] = {
5682 .name = "memsw.usage_in_bytes",
5683 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
5684 .read = mem_cgroup_read,
5685 .register_event = mem_cgroup_usage_register_event,
5686 .unregister_event = mem_cgroup_usage_unregister_event,
5689 .name = "memsw.max_usage_in_bytes",
5690 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
5691 .trigger = mem_cgroup_reset,
5692 .read = mem_cgroup_read,
5695 .name = "memsw.limit_in_bytes",
5696 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
5697 .write_string = mem_cgroup_write,
5698 .read = mem_cgroup_read,
5701 .name = "memsw.failcnt",
5702 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
5703 .trigger = mem_cgroup_reset,
5704 .read = mem_cgroup_read,
5706 { }, /* terminate */
5709 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5711 struct mem_cgroup_per_node *pn;
5712 struct mem_cgroup_per_zone *mz;
5713 int zone, tmp = node;
5715 * This routine is called against possible nodes.
5716 * But it's BUG to call kmalloc() against offline node.
5718 * TODO: this routine can waste much memory for nodes which will
5719 * never be onlined. It's better to use memory hotplug callback
5722 if (!node_state(node, N_NORMAL_MEMORY))
5724 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5728 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
5729 mz = &pn->zoneinfo[zone];
5730 lruvec_init(&mz->lruvec);
5733 memcg->nodeinfo[node] = pn;
5737 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5739 kfree(memcg->nodeinfo[node]);
5742 static struct mem_cgroup *mem_cgroup_alloc(void)
5744 struct mem_cgroup *memcg;
5745 size_t size = memcg_size();
5747 /* Can be very big if nr_node_ids is very big */
5748 if (size < PAGE_SIZE)
5749 memcg = kzalloc(size, GFP_KERNEL);
5751 memcg = vzalloc(size);
5756 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
5759 spin_lock_init(&memcg->pcp_counter_lock);
5763 if (size < PAGE_SIZE)
5771 * At destroying mem_cgroup, references from swap_cgroup can remain.
5772 * (scanning all at force_empty is too costly...)
5774 * Instead of clearing all references at force_empty, we remember
5775 * the number of reference from swap_cgroup and free mem_cgroup when
5776 * it goes down to 0.
5778 * Removal of cgroup itself succeeds regardless of refs from swap.
5781 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5784 size_t size = memcg_size();
5786 free_css_id(&mem_cgroup_subsys, &memcg->css);
5789 free_mem_cgroup_per_zone_info(memcg, node);
5791 free_percpu(memcg->stat);
5794 * We need to make sure that (at least for now), the jump label
5795 * destruction code runs outside of the cgroup lock. This is because
5796 * get_online_cpus(), which is called from the static_branch update,
5797 * can't be called inside the cgroup_lock. cpusets are the ones
5798 * enforcing this dependency, so if they ever change, we might as well.
5800 * schedule_work() will guarantee this happens. Be careful if you need
5801 * to move this code around, and make sure it is outside
5804 disarm_static_keys(memcg);
5805 if (size < PAGE_SIZE)
5812 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
5814 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
5816 if (!memcg->res.parent)
5818 return mem_cgroup_from_res_counter(memcg->res.parent, res);
5820 EXPORT_SYMBOL(parent_mem_cgroup);
5822 static struct cgroup_subsys_state * __ref
5823 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5825 struct mem_cgroup *memcg;
5826 long error = -ENOMEM;
5829 memcg = mem_cgroup_alloc();
5831 return ERR_PTR(error);
5834 if (alloc_mem_cgroup_per_zone_info(memcg, node))
5838 if (parent_css == NULL) {
5839 root_mem_cgroup = memcg;
5840 res_counter_init(&memcg->res, NULL);
5841 res_counter_init(&memcg->memsw, NULL);
5842 res_counter_init(&memcg->kmem, NULL);
5845 memcg->last_scanned_node = MAX_NUMNODES;
5846 INIT_LIST_HEAD(&memcg->oom_notify);
5847 memcg->move_charge_at_immigrate = 0;
5848 mutex_init(&memcg->thresholds_lock);
5849 spin_lock_init(&memcg->move_lock);
5850 vmpressure_init(&memcg->vmpressure);
5855 __mem_cgroup_free(memcg);
5856 return ERR_PTR(error);
5860 mem_cgroup_css_online(struct cgroup_subsys_state *css)
5862 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5863 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css));
5869 mutex_lock(&memcg_create_mutex);
5871 memcg->use_hierarchy = parent->use_hierarchy;
5872 memcg->oom_kill_disable = parent->oom_kill_disable;
5873 memcg->swappiness = mem_cgroup_swappiness(parent);
5875 if (parent->use_hierarchy) {
5876 res_counter_init(&memcg->res, &parent->res);
5877 res_counter_init(&memcg->memsw, &parent->memsw);
5878 res_counter_init(&memcg->kmem, &parent->kmem);
5881 * No need to take a reference to the parent because cgroup
5882 * core guarantees its existence.
5885 res_counter_init(&memcg->res, NULL);
5886 res_counter_init(&memcg->memsw, NULL);
5887 res_counter_init(&memcg->kmem, NULL);
5889 * Deeper hierachy with use_hierarchy == false doesn't make
5890 * much sense so let cgroup subsystem know about this
5891 * unfortunate state in our controller.
5893 if (parent != root_mem_cgroup)
5894 mem_cgroup_subsys.broken_hierarchy = true;
5897 error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
5898 mutex_unlock(&memcg_create_mutex);
5903 * Announce all parents that a group from their hierarchy is gone.
5905 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
5907 struct mem_cgroup *parent = memcg;
5909 while ((parent = parent_mem_cgroup(parent)))
5910 mem_cgroup_iter_invalidate(parent);
5913 * if the root memcg is not hierarchical we have to check it
5916 if (!root_mem_cgroup->use_hierarchy)
5917 mem_cgroup_iter_invalidate(root_mem_cgroup);
5920 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5922 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5924 kmem_cgroup_css_offline(memcg);
5926 mem_cgroup_invalidate_reclaim_iterators(memcg);
5927 mem_cgroup_reparent_charges(memcg);
5928 mem_cgroup_destroy_all_caches(memcg);
5929 vmpressure_cleanup(&memcg->vmpressure);
5932 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5934 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5936 memcg_destroy_kmem(memcg);
5937 __mem_cgroup_free(memcg);
5941 /* Handlers for move charge at task migration. */
5942 #define PRECHARGE_COUNT_AT_ONCE 256
5943 static int mem_cgroup_do_precharge(unsigned long count)
5946 int batch_count = PRECHARGE_COUNT_AT_ONCE;
5947 struct mem_cgroup *memcg = mc.to;
5949 if (mem_cgroup_is_root(memcg)) {
5950 mc.precharge += count;
5951 /* we don't need css_get for root */
5954 /* try to charge at once */
5956 struct res_counter *dummy;
5958 * "memcg" cannot be under rmdir() because we've already checked
5959 * by cgroup_lock_live_cgroup() that it is not removed and we
5960 * are still under the same cgroup_mutex. So we can postpone
5963 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
5965 if (do_swap_account && res_counter_charge(&memcg->memsw,
5966 PAGE_SIZE * count, &dummy)) {
5967 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
5970 mc.precharge += count;
5974 /* fall back to one by one charge */
5976 if (signal_pending(current)) {
5980 if (!batch_count--) {
5981 batch_count = PRECHARGE_COUNT_AT_ONCE;
5984 ret = __mem_cgroup_try_charge(NULL,
5985 GFP_KERNEL, 1, &memcg, false);
5987 /* mem_cgroup_clear_mc() will do uncharge later */
5995 * get_mctgt_type - get target type of moving charge
5996 * @vma: the vma the pte to be checked belongs
5997 * @addr: the address corresponding to the pte to be checked
5998 * @ptent: the pte to be checked
5999 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6002 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6003 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6004 * move charge. if @target is not NULL, the page is stored in target->page
6005 * with extra refcnt got(Callers should handle it).
6006 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6007 * target for charge migration. if @target is not NULL, the entry is stored
6010 * Called with pte lock held.
6017 enum mc_target_type {
6023 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6024 unsigned long addr, pte_t ptent)
6026 struct page *page = vm_normal_page(vma, addr, ptent);
6028 if (!page || !page_mapped(page))
6030 if (PageAnon(page)) {
6031 /* we don't move shared anon */
6034 } else if (!move_file())
6035 /* we ignore mapcount for file pages */
6037 if (!get_page_unless_zero(page))
6044 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6045 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6047 struct page *page = NULL;
6048 swp_entry_t ent = pte_to_swp_entry(ptent);
6050 if (!move_anon() || non_swap_entry(ent))
6053 * Because lookup_swap_cache() updates some statistics counter,
6054 * we call find_get_page() with swapper_space directly.
6056 page = find_get_page(swap_address_space(ent), ent.val);
6057 if (do_swap_account)
6058 entry->val = ent.val;
6063 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6064 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6070 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6071 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6073 struct page *page = NULL;
6074 struct address_space *mapping;
6077 if (!vma->vm_file) /* anonymous vma */
6082 mapping = vma->vm_file->f_mapping;
6083 if (pte_none(ptent))
6084 pgoff = linear_page_index(vma, addr);
6085 else /* pte_file(ptent) is true */
6086 pgoff = pte_to_pgoff(ptent);
6088 /* page is moved even if it's not RSS of this task(page-faulted). */
6089 page = find_get_page(mapping, pgoff);
6092 /* shmem/tmpfs may report page out on swap: account for that too. */
6093 if (radix_tree_exceptional_entry(page)) {
6094 swp_entry_t swap = radix_to_swp_entry(page);
6095 if (do_swap_account)
6097 page = find_get_page(swap_address_space(swap), swap.val);
6103 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6104 unsigned long addr, pte_t ptent, union mc_target *target)
6106 struct page *page = NULL;
6107 struct page_cgroup *pc;
6108 enum mc_target_type ret = MC_TARGET_NONE;
6109 swp_entry_t ent = { .val = 0 };
6111 if (pte_present(ptent))
6112 page = mc_handle_present_pte(vma, addr, ptent);
6113 else if (is_swap_pte(ptent))
6114 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
6115 else if (pte_none(ptent) || pte_file(ptent))
6116 page = mc_handle_file_pte(vma, addr, ptent, &ent);
6118 if (!page && !ent.val)
6121 pc = lookup_page_cgroup(page);
6123 * Do only loose check w/o page_cgroup lock.
6124 * mem_cgroup_move_account() checks the pc is valid or not under
6127 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6128 ret = MC_TARGET_PAGE;
6130 target->page = page;
6132 if (!ret || !target)
6135 /* There is a swap entry and a page doesn't exist or isn't charged */
6136 if (ent.val && !ret &&
6137 css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
6138 ret = MC_TARGET_SWAP;
6145 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6147 * We don't consider swapping or file mapped pages because THP does not
6148 * support them for now.
6149 * Caller should make sure that pmd_trans_huge(pmd) is true.
6151 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6152 unsigned long addr, pmd_t pmd, union mc_target *target)
6154 struct page *page = NULL;
6155 struct page_cgroup *pc;
6156 enum mc_target_type ret = MC_TARGET_NONE;
6158 page = pmd_page(pmd);
6159 VM_BUG_ON(!page || !PageHead(page));
6162 pc = lookup_page_cgroup(page);
6163 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6164 ret = MC_TARGET_PAGE;
6167 target->page = page;
6173 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6174 unsigned long addr, pmd_t pmd, union mc_target *target)
6176 return MC_TARGET_NONE;
6180 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6181 unsigned long addr, unsigned long end,
6182 struct mm_walk *walk)
6184 struct vm_area_struct *vma = walk->private;
6188 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6189 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6190 mc.precharge += HPAGE_PMD_NR;
6191 spin_unlock(&vma->vm_mm->page_table_lock);
6195 if (pmd_trans_unstable(pmd))
6197 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6198 for (; addr != end; pte++, addr += PAGE_SIZE)
6199 if (get_mctgt_type(vma, addr, *pte, NULL))
6200 mc.precharge++; /* increment precharge temporarily */
6201 pte_unmap_unlock(pte - 1, ptl);
6207 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6209 unsigned long precharge;
6210 struct vm_area_struct *vma;
6212 down_read(&mm->mmap_sem);
6213 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6214 struct mm_walk mem_cgroup_count_precharge_walk = {
6215 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6219 if (is_vm_hugetlb_page(vma))
6221 walk_page_range(vma->vm_start, vma->vm_end,
6222 &mem_cgroup_count_precharge_walk);
6224 up_read(&mm->mmap_sem);
6226 precharge = mc.precharge;
6232 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6234 unsigned long precharge = mem_cgroup_count_precharge(mm);
6236 VM_BUG_ON(mc.moving_task);
6237 mc.moving_task = current;
6238 return mem_cgroup_do_precharge(precharge);
6241 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6242 static void __mem_cgroup_clear_mc(void)
6244 struct mem_cgroup *from = mc.from;
6245 struct mem_cgroup *to = mc.to;
6248 /* we must uncharge all the leftover precharges from mc.to */
6250 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
6254 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6255 * we must uncharge here.
6257 if (mc.moved_charge) {
6258 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6259 mc.moved_charge = 0;
6261 /* we must fixup refcnts and charges */
6262 if (mc.moved_swap) {
6263 /* uncharge swap account from the old cgroup */
6264 if (!mem_cgroup_is_root(mc.from))
6265 res_counter_uncharge(&mc.from->memsw,
6266 PAGE_SIZE * mc.moved_swap);
6268 for (i = 0; i < mc.moved_swap; i++)
6269 css_put(&mc.from->css);
6271 if (!mem_cgroup_is_root(mc.to)) {
6273 * we charged both to->res and to->memsw, so we should
6276 res_counter_uncharge(&mc.to->res,
6277 PAGE_SIZE * mc.moved_swap);
6279 /* we've already done css_get(mc.to) */
6282 memcg_oom_recover(from);
6283 memcg_oom_recover(to);
6284 wake_up_all(&mc.waitq);
6287 static void mem_cgroup_clear_mc(void)
6289 struct mem_cgroup *from = mc.from;
6292 * we must clear moving_task before waking up waiters at the end of
6295 mc.moving_task = NULL;
6296 __mem_cgroup_clear_mc();
6297 spin_lock(&mc.lock);
6300 spin_unlock(&mc.lock);
6301 mem_cgroup_end_move(from);
6304 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6305 struct cgroup_taskset *tset)
6307 struct task_struct *p = cgroup_taskset_first(tset);
6309 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6310 unsigned long move_charge_at_immigrate;
6313 * We are now commited to this value whatever it is. Changes in this
6314 * tunable will only affect upcoming migrations, not the current one.
6315 * So we need to save it, and keep it going.
6317 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6318 if (move_charge_at_immigrate) {
6319 struct mm_struct *mm;
6320 struct mem_cgroup *from = mem_cgroup_from_task(p);
6322 VM_BUG_ON(from == memcg);
6324 mm = get_task_mm(p);
6327 /* We move charges only when we move a owner of the mm */
6328 if (mm->owner == p) {
6331 VM_BUG_ON(mc.precharge);
6332 VM_BUG_ON(mc.moved_charge);
6333 VM_BUG_ON(mc.moved_swap);
6334 mem_cgroup_start_move(from);
6335 spin_lock(&mc.lock);
6338 mc.immigrate_flags = move_charge_at_immigrate;
6339 spin_unlock(&mc.lock);
6340 /* We set mc.moving_task later */
6342 ret = mem_cgroup_precharge_mc(mm);
6344 mem_cgroup_clear_mc();
6351 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6352 struct cgroup_taskset *tset)
6354 mem_cgroup_clear_mc();
6357 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6358 unsigned long addr, unsigned long end,
6359 struct mm_walk *walk)
6362 struct vm_area_struct *vma = walk->private;
6365 enum mc_target_type target_type;
6366 union mc_target target;
6368 struct page_cgroup *pc;
6371 * We don't take compound_lock() here but no race with splitting thp
6373 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6374 * under splitting, which means there's no concurrent thp split,
6375 * - if another thread runs into split_huge_page() just after we
6376 * entered this if-block, the thread must wait for page table lock
6377 * to be unlocked in __split_huge_page_splitting(), where the main
6378 * part of thp split is not executed yet.
6380 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6381 if (mc.precharge < HPAGE_PMD_NR) {
6382 spin_unlock(&vma->vm_mm->page_table_lock);
6385 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6386 if (target_type == MC_TARGET_PAGE) {
6388 if (!isolate_lru_page(page)) {
6389 pc = lookup_page_cgroup(page);
6390 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6391 pc, mc.from, mc.to)) {
6392 mc.precharge -= HPAGE_PMD_NR;
6393 mc.moved_charge += HPAGE_PMD_NR;
6395 putback_lru_page(page);
6399 spin_unlock(&vma->vm_mm->page_table_lock);
6403 if (pmd_trans_unstable(pmd))
6406 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6407 for (; addr != end; addr += PAGE_SIZE) {
6408 pte_t ptent = *(pte++);
6414 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6415 case MC_TARGET_PAGE:
6417 if (isolate_lru_page(page))
6419 pc = lookup_page_cgroup(page);
6420 if (!mem_cgroup_move_account(page, 1, pc,
6423 /* we uncharge from mc.from later. */
6426 putback_lru_page(page);
6427 put: /* get_mctgt_type() gets the page */
6430 case MC_TARGET_SWAP:
6432 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6434 /* we fixup refcnts and charges later. */
6442 pte_unmap_unlock(pte - 1, ptl);
6447 * We have consumed all precharges we got in can_attach().
6448 * We try charge one by one, but don't do any additional
6449 * charges to mc.to if we have failed in charge once in attach()
6452 ret = mem_cgroup_do_precharge(1);
6460 static void mem_cgroup_move_charge(struct mm_struct *mm)
6462 struct vm_area_struct *vma;
6464 lru_add_drain_all();
6466 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6468 * Someone who are holding the mmap_sem might be waiting in
6469 * waitq. So we cancel all extra charges, wake up all waiters,
6470 * and retry. Because we cancel precharges, we might not be able
6471 * to move enough charges, but moving charge is a best-effort
6472 * feature anyway, so it wouldn't be a big problem.
6474 __mem_cgroup_clear_mc();
6478 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6480 struct mm_walk mem_cgroup_move_charge_walk = {
6481 .pmd_entry = mem_cgroup_move_charge_pte_range,
6485 if (is_vm_hugetlb_page(vma))
6487 ret = walk_page_range(vma->vm_start, vma->vm_end,
6488 &mem_cgroup_move_charge_walk);
6491 * means we have consumed all precharges and failed in
6492 * doing additional charge. Just abandon here.
6496 up_read(&mm->mmap_sem);
6499 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6500 struct cgroup_taskset *tset)
6502 struct task_struct *p = cgroup_taskset_first(tset);
6503 struct mm_struct *mm = get_task_mm(p);
6507 mem_cgroup_move_charge(mm);
6511 mem_cgroup_clear_mc();
6513 #else /* !CONFIG_MMU */
6514 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6515 struct cgroup_taskset *tset)
6519 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6520 struct cgroup_taskset *tset)
6523 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6524 struct cgroup_taskset *tset)
6530 * Cgroup retains root cgroups across [un]mount cycles making it necessary
6531 * to verify sane_behavior flag on each mount attempt.
6533 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
6536 * use_hierarchy is forced with sane_behavior. cgroup core
6537 * guarantees that @root doesn't have any children, so turning it
6538 * on for the root memcg is enough.
6540 if (cgroup_sane_behavior(root_css->cgroup))
6541 mem_cgroup_from_css(root_css)->use_hierarchy = true;
6544 struct cgroup_subsys mem_cgroup_subsys = {
6546 .subsys_id = mem_cgroup_subsys_id,
6547 .css_alloc = mem_cgroup_css_alloc,
6548 .css_online = mem_cgroup_css_online,
6549 .css_offline = mem_cgroup_css_offline,
6550 .css_free = mem_cgroup_css_free,
6551 .can_attach = mem_cgroup_can_attach,
6552 .cancel_attach = mem_cgroup_cancel_attach,
6553 .attach = mem_cgroup_move_task,
6554 .bind = mem_cgroup_bind,
6555 .base_cftypes = mem_cgroup_files,
6560 #ifdef CONFIG_MEMCG_SWAP
6561 static int __init enable_swap_account(char *s)
6563 if (!strcmp(s, "1"))
6564 really_do_swap_account = 1;
6565 else if (!strcmp(s, "0"))
6566 really_do_swap_account = 0;
6569 __setup("swapaccount=", enable_swap_account);
6571 static void __init memsw_file_init(void)
6573 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files));
6576 static void __init enable_swap_cgroup(void)
6578 if (!mem_cgroup_disabled() && really_do_swap_account) {
6579 do_swap_account = 1;
6585 static void __init enable_swap_cgroup(void)
6591 * subsys_initcall() for memory controller.
6593 * Some parts like hotcpu_notifier() have to be initialized from this context
6594 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6595 * everything that doesn't depend on a specific mem_cgroup structure should
6596 * be initialized from here.
6598 static int __init mem_cgroup_init(void)
6600 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6601 enable_swap_cgroup();
6605 subsys_initcall(mem_cgroup_init);