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 under the given root
1778 * a) it is over its soft limit
1779 * b) any parent up the hierarchy is over its soft limit
1781 bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup *memcg,
1782 struct mem_cgroup *root)
1784 struct mem_cgroup *parent = memcg;
1786 if (res_counter_soft_limit_excess(&memcg->res))
1790 * If any parent up to the root in the hierarchy is over its soft limit
1791 * then we have to obey and reclaim from this group as well.
1793 while((parent = parent_mem_cgroup(parent))) {
1794 if (res_counter_soft_limit_excess(&parent->res))
1804 * Check OOM-Killer is already running under our hierarchy.
1805 * If someone is running, return false.
1806 * Has to be called with memcg_oom_lock
1808 static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
1810 struct mem_cgroup *iter, *failed = NULL;
1812 for_each_mem_cgroup_tree(iter, memcg) {
1813 if (iter->oom_lock) {
1815 * this subtree of our hierarchy is already locked
1816 * so we cannot give a lock.
1819 mem_cgroup_iter_break(memcg, iter);
1822 iter->oom_lock = true;
1829 * OK, we failed to lock the whole subtree so we have to clean up
1830 * what we set up to the failing subtree
1832 for_each_mem_cgroup_tree(iter, memcg) {
1833 if (iter == failed) {
1834 mem_cgroup_iter_break(memcg, iter);
1837 iter->oom_lock = false;
1843 * Has to be called with memcg_oom_lock
1845 static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1847 struct mem_cgroup *iter;
1849 for_each_mem_cgroup_tree(iter, memcg)
1850 iter->oom_lock = false;
1854 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1856 struct mem_cgroup *iter;
1858 for_each_mem_cgroup_tree(iter, memcg)
1859 atomic_inc(&iter->under_oom);
1862 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1864 struct mem_cgroup *iter;
1867 * When a new child is created while the hierarchy is under oom,
1868 * mem_cgroup_oom_lock() may not be called. We have to use
1869 * atomic_add_unless() here.
1871 for_each_mem_cgroup_tree(iter, memcg)
1872 atomic_add_unless(&iter->under_oom, -1, 0);
1875 static DEFINE_SPINLOCK(memcg_oom_lock);
1876 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1878 struct oom_wait_info {
1879 struct mem_cgroup *memcg;
1883 static int memcg_oom_wake_function(wait_queue_t *wait,
1884 unsigned mode, int sync, void *arg)
1886 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1887 struct mem_cgroup *oom_wait_memcg;
1888 struct oom_wait_info *oom_wait_info;
1890 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1891 oom_wait_memcg = oom_wait_info->memcg;
1894 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
1895 * Then we can use css_is_ancestor without taking care of RCU.
1897 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
1898 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
1900 return autoremove_wake_function(wait, mode, sync, arg);
1903 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1905 /* for filtering, pass "memcg" as argument. */
1906 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1909 static void memcg_oom_recover(struct mem_cgroup *memcg)
1911 if (memcg && atomic_read(&memcg->under_oom))
1912 memcg_wakeup_oom(memcg);
1916 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1918 static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask,
1921 struct oom_wait_info owait;
1922 bool locked, need_to_kill;
1924 owait.memcg = memcg;
1925 owait.wait.flags = 0;
1926 owait.wait.func = memcg_oom_wake_function;
1927 owait.wait.private = current;
1928 INIT_LIST_HEAD(&owait.wait.task_list);
1929 need_to_kill = true;
1930 mem_cgroup_mark_under_oom(memcg);
1932 /* At first, try to OOM lock hierarchy under memcg.*/
1933 spin_lock(&memcg_oom_lock);
1934 locked = mem_cgroup_oom_lock(memcg);
1936 * Even if signal_pending(), we can't quit charge() loop without
1937 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1938 * under OOM is always welcomed, use TASK_KILLABLE here.
1940 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1941 if (!locked || memcg->oom_kill_disable)
1942 need_to_kill = false;
1944 mem_cgroup_oom_notify(memcg);
1945 spin_unlock(&memcg_oom_lock);
1948 finish_wait(&memcg_oom_waitq, &owait.wait);
1949 mem_cgroup_out_of_memory(memcg, mask, order);
1952 finish_wait(&memcg_oom_waitq, &owait.wait);
1954 spin_lock(&memcg_oom_lock);
1956 mem_cgroup_oom_unlock(memcg);
1957 memcg_wakeup_oom(memcg);
1958 spin_unlock(&memcg_oom_lock);
1960 mem_cgroup_unmark_under_oom(memcg);
1962 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1964 /* Give chance to dying process */
1965 schedule_timeout_uninterruptible(1);
1970 * Currently used to update mapped file statistics, but the routine can be
1971 * generalized to update other statistics as well.
1973 * Notes: Race condition
1975 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1976 * it tends to be costly. But considering some conditions, we doesn't need
1977 * to do so _always_.
1979 * Considering "charge", lock_page_cgroup() is not required because all
1980 * file-stat operations happen after a page is attached to radix-tree. There
1981 * are no race with "charge".
1983 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1984 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1985 * if there are race with "uncharge". Statistics itself is properly handled
1988 * Considering "move", this is an only case we see a race. To make the race
1989 * small, we check mm->moving_account and detect there are possibility of race
1990 * If there is, we take a lock.
1993 void __mem_cgroup_begin_update_page_stat(struct page *page,
1994 bool *locked, unsigned long *flags)
1996 struct mem_cgroup *memcg;
1997 struct page_cgroup *pc;
1999 pc = lookup_page_cgroup(page);
2001 memcg = pc->mem_cgroup;
2002 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2005 * If this memory cgroup is not under account moving, we don't
2006 * need to take move_lock_mem_cgroup(). Because we already hold
2007 * rcu_read_lock(), any calls to move_account will be delayed until
2008 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2010 if (!mem_cgroup_stolen(memcg))
2013 move_lock_mem_cgroup(memcg, flags);
2014 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2015 move_unlock_mem_cgroup(memcg, flags);
2021 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2023 struct page_cgroup *pc = lookup_page_cgroup(page);
2026 * It's guaranteed that pc->mem_cgroup never changes while
2027 * lock is held because a routine modifies pc->mem_cgroup
2028 * should take move_lock_mem_cgroup().
2030 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2033 void mem_cgroup_update_page_stat(struct page *page,
2034 enum mem_cgroup_page_stat_item idx, int val)
2036 struct mem_cgroup *memcg;
2037 struct page_cgroup *pc = lookup_page_cgroup(page);
2038 unsigned long uninitialized_var(flags);
2040 if (mem_cgroup_disabled())
2043 memcg = pc->mem_cgroup;
2044 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2048 case MEMCG_NR_FILE_MAPPED:
2049 idx = MEM_CGROUP_STAT_FILE_MAPPED;
2055 this_cpu_add(memcg->stat->count[idx], val);
2059 * size of first charge trial. "32" comes from vmscan.c's magic value.
2060 * TODO: maybe necessary to use big numbers in big irons.
2062 #define CHARGE_BATCH 32U
2063 struct memcg_stock_pcp {
2064 struct mem_cgroup *cached; /* this never be root cgroup */
2065 unsigned int nr_pages;
2066 struct work_struct work;
2067 unsigned long flags;
2068 #define FLUSHING_CACHED_CHARGE 0
2070 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2071 static DEFINE_MUTEX(percpu_charge_mutex);
2074 * consume_stock: Try to consume stocked charge on this cpu.
2075 * @memcg: memcg to consume from.
2076 * @nr_pages: how many pages to charge.
2078 * The charges will only happen if @memcg matches the current cpu's memcg
2079 * stock, and at least @nr_pages are available in that stock. Failure to
2080 * service an allocation will refill the stock.
2082 * returns true if successful, false otherwise.
2084 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2086 struct memcg_stock_pcp *stock;
2089 if (nr_pages > CHARGE_BATCH)
2092 stock = &get_cpu_var(memcg_stock);
2093 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2094 stock->nr_pages -= nr_pages;
2095 else /* need to call res_counter_charge */
2097 put_cpu_var(memcg_stock);
2102 * Returns stocks cached in percpu to res_counter and reset cached information.
2104 static void drain_stock(struct memcg_stock_pcp *stock)
2106 struct mem_cgroup *old = stock->cached;
2108 if (stock->nr_pages) {
2109 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2111 res_counter_uncharge(&old->res, bytes);
2112 if (do_swap_account)
2113 res_counter_uncharge(&old->memsw, bytes);
2114 stock->nr_pages = 0;
2116 stock->cached = NULL;
2120 * This must be called under preempt disabled or must be called by
2121 * a thread which is pinned to local cpu.
2123 static void drain_local_stock(struct work_struct *dummy)
2125 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2127 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2130 static void __init memcg_stock_init(void)
2134 for_each_possible_cpu(cpu) {
2135 struct memcg_stock_pcp *stock =
2136 &per_cpu(memcg_stock, cpu);
2137 INIT_WORK(&stock->work, drain_local_stock);
2142 * Cache charges(val) which is from res_counter, to local per_cpu area.
2143 * This will be consumed by consume_stock() function, later.
2145 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2147 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2149 if (stock->cached != memcg) { /* reset if necessary */
2151 stock->cached = memcg;
2153 stock->nr_pages += nr_pages;
2154 put_cpu_var(memcg_stock);
2158 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2159 * of the hierarchy under it. sync flag says whether we should block
2160 * until the work is done.
2162 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2166 /* Notify other cpus that system-wide "drain" is running */
2169 for_each_online_cpu(cpu) {
2170 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2171 struct mem_cgroup *memcg;
2173 memcg = stock->cached;
2174 if (!memcg || !stock->nr_pages)
2176 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2178 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2180 drain_local_stock(&stock->work);
2182 schedule_work_on(cpu, &stock->work);
2190 for_each_online_cpu(cpu) {
2191 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2192 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2193 flush_work(&stock->work);
2200 * Tries to drain stocked charges in other cpus. This function is asynchronous
2201 * and just put a work per cpu for draining localy on each cpu. Caller can
2202 * expects some charges will be back to res_counter later but cannot wait for
2205 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2208 * If someone calls draining, avoid adding more kworker runs.
2210 if (!mutex_trylock(&percpu_charge_mutex))
2212 drain_all_stock(root_memcg, false);
2213 mutex_unlock(&percpu_charge_mutex);
2216 /* This is a synchronous drain interface. */
2217 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2219 /* called when force_empty is called */
2220 mutex_lock(&percpu_charge_mutex);
2221 drain_all_stock(root_memcg, true);
2222 mutex_unlock(&percpu_charge_mutex);
2226 * This function drains percpu counter value from DEAD cpu and
2227 * move it to local cpu. Note that this function can be preempted.
2229 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2233 spin_lock(&memcg->pcp_counter_lock);
2234 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2235 long x = per_cpu(memcg->stat->count[i], cpu);
2237 per_cpu(memcg->stat->count[i], cpu) = 0;
2238 memcg->nocpu_base.count[i] += x;
2240 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2241 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2243 per_cpu(memcg->stat->events[i], cpu) = 0;
2244 memcg->nocpu_base.events[i] += x;
2246 spin_unlock(&memcg->pcp_counter_lock);
2249 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2250 unsigned long action,
2253 int cpu = (unsigned long)hcpu;
2254 struct memcg_stock_pcp *stock;
2255 struct mem_cgroup *iter;
2257 if (action == CPU_ONLINE)
2260 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2263 for_each_mem_cgroup(iter)
2264 mem_cgroup_drain_pcp_counter(iter, cpu);
2266 stock = &per_cpu(memcg_stock, cpu);
2272 /* See __mem_cgroup_try_charge() for details */
2274 CHARGE_OK, /* success */
2275 CHARGE_RETRY, /* need to retry but retry is not bad */
2276 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2277 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
2278 CHARGE_OOM_DIE, /* the current is killed because of OOM */
2281 static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2282 unsigned int nr_pages, unsigned int min_pages,
2285 unsigned long csize = nr_pages * PAGE_SIZE;
2286 struct mem_cgroup *mem_over_limit;
2287 struct res_counter *fail_res;
2288 unsigned long flags = 0;
2291 ret = res_counter_charge(&memcg->res, csize, &fail_res);
2294 if (!do_swap_account)
2296 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2300 res_counter_uncharge(&memcg->res, csize);
2301 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2302 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2304 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2306 * Never reclaim on behalf of optional batching, retry with a
2307 * single page instead.
2309 if (nr_pages > min_pages)
2310 return CHARGE_RETRY;
2312 if (!(gfp_mask & __GFP_WAIT))
2313 return CHARGE_WOULDBLOCK;
2315 if (gfp_mask & __GFP_NORETRY)
2316 return CHARGE_NOMEM;
2318 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2319 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2320 return CHARGE_RETRY;
2322 * Even though the limit is exceeded at this point, reclaim
2323 * may have been able to free some pages. Retry the charge
2324 * before killing the task.
2326 * Only for regular pages, though: huge pages are rather
2327 * unlikely to succeed so close to the limit, and we fall back
2328 * to regular pages anyway in case of failure.
2330 if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
2331 return CHARGE_RETRY;
2334 * At task move, charge accounts can be doubly counted. So, it's
2335 * better to wait until the end of task_move if something is going on.
2337 if (mem_cgroup_wait_acct_move(mem_over_limit))
2338 return CHARGE_RETRY;
2340 /* If we don't need to call oom-killer at el, return immediately */
2342 return CHARGE_NOMEM;
2344 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))
2345 return CHARGE_OOM_DIE;
2347 return CHARGE_RETRY;
2351 * __mem_cgroup_try_charge() does
2352 * 1. detect memcg to be charged against from passed *mm and *ptr,
2353 * 2. update res_counter
2354 * 3. call memory reclaim if necessary.
2356 * In some special case, if the task is fatal, fatal_signal_pending() or
2357 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2358 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2359 * as possible without any hazards. 2: all pages should have a valid
2360 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2361 * pointer, that is treated as a charge to root_mem_cgroup.
2363 * So __mem_cgroup_try_charge() will return
2364 * 0 ... on success, filling *ptr with a valid memcg pointer.
2365 * -ENOMEM ... charge failure because of resource limits.
2366 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2368 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2369 * the oom-killer can be invoked.
2371 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2373 unsigned int nr_pages,
2374 struct mem_cgroup **ptr,
2377 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2378 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2379 struct mem_cgroup *memcg = NULL;
2383 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2384 * in system level. So, allow to go ahead dying process in addition to
2387 if (unlikely(test_thread_flag(TIF_MEMDIE)
2388 || fatal_signal_pending(current)))
2392 * We always charge the cgroup the mm_struct belongs to.
2393 * The mm_struct's mem_cgroup changes on task migration if the
2394 * thread group leader migrates. It's possible that mm is not
2395 * set, if so charge the root memcg (happens for pagecache usage).
2398 *ptr = root_mem_cgroup;
2400 if (*ptr) { /* css should be a valid one */
2402 if (mem_cgroup_is_root(memcg))
2404 if (consume_stock(memcg, nr_pages))
2406 css_get(&memcg->css);
2408 struct task_struct *p;
2411 p = rcu_dereference(mm->owner);
2413 * Because we don't have task_lock(), "p" can exit.
2414 * In that case, "memcg" can point to root or p can be NULL with
2415 * race with swapoff. Then, we have small risk of mis-accouning.
2416 * But such kind of mis-account by race always happens because
2417 * we don't have cgroup_mutex(). It's overkill and we allo that
2419 * (*) swapoff at el will charge against mm-struct not against
2420 * task-struct. So, mm->owner can be NULL.
2422 memcg = mem_cgroup_from_task(p);
2424 memcg = root_mem_cgroup;
2425 if (mem_cgroup_is_root(memcg)) {
2429 if (consume_stock(memcg, nr_pages)) {
2431 * It seems dagerous to access memcg without css_get().
2432 * But considering how consume_stok works, it's not
2433 * necessary. If consume_stock success, some charges
2434 * from this memcg are cached on this cpu. So, we
2435 * don't need to call css_get()/css_tryget() before
2436 * calling consume_stock().
2441 /* after here, we may be blocked. we need to get refcnt */
2442 if (!css_tryget(&memcg->css)) {
2452 /* If killed, bypass charge */
2453 if (fatal_signal_pending(current)) {
2454 css_put(&memcg->css);
2459 if (oom && !nr_oom_retries) {
2461 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2464 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
2469 case CHARGE_RETRY: /* not in OOM situation but retry */
2471 css_put(&memcg->css);
2474 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2475 css_put(&memcg->css);
2477 case CHARGE_NOMEM: /* OOM routine works */
2479 css_put(&memcg->css);
2482 /* If oom, we never return -ENOMEM */
2485 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2486 css_put(&memcg->css);
2489 } while (ret != CHARGE_OK);
2491 if (batch > nr_pages)
2492 refill_stock(memcg, batch - nr_pages);
2493 css_put(&memcg->css);
2501 *ptr = root_mem_cgroup;
2506 * Somemtimes we have to undo a charge we got by try_charge().
2507 * This function is for that and do uncharge, put css's refcnt.
2508 * gotten by try_charge().
2510 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2511 unsigned int nr_pages)
2513 if (!mem_cgroup_is_root(memcg)) {
2514 unsigned long bytes = nr_pages * PAGE_SIZE;
2516 res_counter_uncharge(&memcg->res, bytes);
2517 if (do_swap_account)
2518 res_counter_uncharge(&memcg->memsw, bytes);
2523 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2524 * This is useful when moving usage to parent cgroup.
2526 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2527 unsigned int nr_pages)
2529 unsigned long bytes = nr_pages * PAGE_SIZE;
2531 if (mem_cgroup_is_root(memcg))
2534 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2535 if (do_swap_account)
2536 res_counter_uncharge_until(&memcg->memsw,
2537 memcg->memsw.parent, bytes);
2541 * A helper function to get mem_cgroup from ID. must be called under
2542 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2543 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2544 * called against removed memcg.)
2546 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2548 struct cgroup_subsys_state *css;
2550 /* ID 0 is unused ID */
2553 css = css_lookup(&mem_cgroup_subsys, id);
2556 return mem_cgroup_from_css(css);
2559 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2561 struct mem_cgroup *memcg = NULL;
2562 struct page_cgroup *pc;
2566 VM_BUG_ON(!PageLocked(page));
2568 pc = lookup_page_cgroup(page);
2569 lock_page_cgroup(pc);
2570 if (PageCgroupUsed(pc)) {
2571 memcg = pc->mem_cgroup;
2572 if (memcg && !css_tryget(&memcg->css))
2574 } else if (PageSwapCache(page)) {
2575 ent.val = page_private(page);
2576 id = lookup_swap_cgroup_id(ent);
2578 memcg = mem_cgroup_lookup(id);
2579 if (memcg && !css_tryget(&memcg->css))
2583 unlock_page_cgroup(pc);
2587 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2589 unsigned int nr_pages,
2590 enum charge_type ctype,
2593 struct page_cgroup *pc = lookup_page_cgroup(page);
2594 struct zone *uninitialized_var(zone);
2595 struct lruvec *lruvec;
2596 bool was_on_lru = false;
2599 lock_page_cgroup(pc);
2600 VM_BUG_ON(PageCgroupUsed(pc));
2602 * we don't need page_cgroup_lock about tail pages, becase they are not
2603 * accessed by any other context at this point.
2607 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2608 * may already be on some other mem_cgroup's LRU. Take care of it.
2611 zone = page_zone(page);
2612 spin_lock_irq(&zone->lru_lock);
2613 if (PageLRU(page)) {
2614 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2616 del_page_from_lru_list(page, lruvec, page_lru(page));
2621 pc->mem_cgroup = memcg;
2623 * We access a page_cgroup asynchronously without lock_page_cgroup().
2624 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2625 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2626 * before USED bit, we need memory barrier here.
2627 * See mem_cgroup_add_lru_list(), etc.
2630 SetPageCgroupUsed(pc);
2634 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2635 VM_BUG_ON(PageLRU(page));
2637 add_page_to_lru_list(page, lruvec, page_lru(page));
2639 spin_unlock_irq(&zone->lru_lock);
2642 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2647 mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
2648 unlock_page_cgroup(pc);
2651 * "charge_statistics" updated event counter.
2653 memcg_check_events(memcg, page);
2656 static DEFINE_MUTEX(set_limit_mutex);
2658 #ifdef CONFIG_MEMCG_KMEM
2659 static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2661 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2662 (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK);
2666 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2667 * in the memcg_cache_params struct.
2669 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2671 struct kmem_cache *cachep;
2673 VM_BUG_ON(p->is_root_cache);
2674 cachep = p->root_cache;
2675 return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)];
2678 #ifdef CONFIG_SLABINFO
2679 static int mem_cgroup_slabinfo_read(struct cgroup_subsys_state *css,
2680 struct cftype *cft, struct seq_file *m)
2682 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
2683 struct memcg_cache_params *params;
2685 if (!memcg_can_account_kmem(memcg))
2688 print_slabinfo_header(m);
2690 mutex_lock(&memcg->slab_caches_mutex);
2691 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2692 cache_show(memcg_params_to_cache(params), m);
2693 mutex_unlock(&memcg->slab_caches_mutex);
2699 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2701 struct res_counter *fail_res;
2702 struct mem_cgroup *_memcg;
2706 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2711 * Conditions under which we can wait for the oom_killer. Those are
2712 * the same conditions tested by the core page allocator
2714 may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY);
2717 ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT,
2720 if (ret == -EINTR) {
2722 * __mem_cgroup_try_charge() chosed to bypass to root due to
2723 * OOM kill or fatal signal. Since our only options are to
2724 * either fail the allocation or charge it to this cgroup, do
2725 * it as a temporary condition. But we can't fail. From a
2726 * kmem/slab perspective, the cache has already been selected,
2727 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2730 * This condition will only trigger if the task entered
2731 * memcg_charge_kmem in a sane state, but was OOM-killed during
2732 * __mem_cgroup_try_charge() above. Tasks that were already
2733 * dying when the allocation triggers should have been already
2734 * directed to the root cgroup in memcontrol.h
2736 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2737 if (do_swap_account)
2738 res_counter_charge_nofail(&memcg->memsw, size,
2742 res_counter_uncharge(&memcg->kmem, size);
2747 static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2749 res_counter_uncharge(&memcg->res, size);
2750 if (do_swap_account)
2751 res_counter_uncharge(&memcg->memsw, size);
2754 if (res_counter_uncharge(&memcg->kmem, size))
2758 * Releases a reference taken in kmem_cgroup_css_offline in case
2759 * this last uncharge is racing with the offlining code or it is
2760 * outliving the memcg existence.
2762 * The memory barrier imposed by test&clear is paired with the
2763 * explicit one in memcg_kmem_mark_dead().
2765 if (memcg_kmem_test_and_clear_dead(memcg))
2766 css_put(&memcg->css);
2769 void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep)
2774 mutex_lock(&memcg->slab_caches_mutex);
2775 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
2776 mutex_unlock(&memcg->slab_caches_mutex);
2780 * helper for acessing a memcg's index. It will be used as an index in the
2781 * child cache array in kmem_cache, and also to derive its name. This function
2782 * will return -1 when this is not a kmem-limited memcg.
2784 int memcg_cache_id(struct mem_cgroup *memcg)
2786 return memcg ? memcg->kmemcg_id : -1;
2790 * This ends up being protected by the set_limit mutex, during normal
2791 * operation, because that is its main call site.
2793 * But when we create a new cache, we can call this as well if its parent
2794 * is kmem-limited. That will have to hold set_limit_mutex as well.
2796 int memcg_update_cache_sizes(struct mem_cgroup *memcg)
2800 num = ida_simple_get(&kmem_limited_groups,
2801 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2805 * After this point, kmem_accounted (that we test atomically in
2806 * the beginning of this conditional), is no longer 0. This
2807 * guarantees only one process will set the following boolean
2808 * to true. We don't need test_and_set because we're protected
2809 * by the set_limit_mutex anyway.
2811 memcg_kmem_set_activated(memcg);
2813 ret = memcg_update_all_caches(num+1);
2815 ida_simple_remove(&kmem_limited_groups, num);
2816 memcg_kmem_clear_activated(memcg);
2820 memcg->kmemcg_id = num;
2821 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
2822 mutex_init(&memcg->slab_caches_mutex);
2826 static size_t memcg_caches_array_size(int num_groups)
2829 if (num_groups <= 0)
2832 size = 2 * num_groups;
2833 if (size < MEMCG_CACHES_MIN_SIZE)
2834 size = MEMCG_CACHES_MIN_SIZE;
2835 else if (size > MEMCG_CACHES_MAX_SIZE)
2836 size = MEMCG_CACHES_MAX_SIZE;
2842 * We should update the current array size iff all caches updates succeed. This
2843 * can only be done from the slab side. The slab mutex needs to be held when
2846 void memcg_update_array_size(int num)
2848 if (num > memcg_limited_groups_array_size)
2849 memcg_limited_groups_array_size = memcg_caches_array_size(num);
2852 static void kmem_cache_destroy_work_func(struct work_struct *w);
2854 int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
2856 struct memcg_cache_params *cur_params = s->memcg_params;
2858 VM_BUG_ON(s->memcg_params && !s->memcg_params->is_root_cache);
2860 if (num_groups > memcg_limited_groups_array_size) {
2862 ssize_t size = memcg_caches_array_size(num_groups);
2864 size *= sizeof(void *);
2865 size += offsetof(struct memcg_cache_params, memcg_caches);
2867 s->memcg_params = kzalloc(size, GFP_KERNEL);
2868 if (!s->memcg_params) {
2869 s->memcg_params = cur_params;
2873 s->memcg_params->is_root_cache = true;
2876 * There is the chance it will be bigger than
2877 * memcg_limited_groups_array_size, if we failed an allocation
2878 * in a cache, in which case all caches updated before it, will
2879 * have a bigger array.
2881 * But if that is the case, the data after
2882 * memcg_limited_groups_array_size is certainly unused
2884 for (i = 0; i < memcg_limited_groups_array_size; i++) {
2885 if (!cur_params->memcg_caches[i])
2887 s->memcg_params->memcg_caches[i] =
2888 cur_params->memcg_caches[i];
2892 * Ideally, we would wait until all caches succeed, and only
2893 * then free the old one. But this is not worth the extra
2894 * pointer per-cache we'd have to have for this.
2896 * It is not a big deal if some caches are left with a size
2897 * bigger than the others. And all updates will reset this
2905 int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
2906 struct kmem_cache *root_cache)
2910 if (!memcg_kmem_enabled())
2914 size = offsetof(struct memcg_cache_params, memcg_caches);
2915 size += memcg_limited_groups_array_size * sizeof(void *);
2917 size = sizeof(struct memcg_cache_params);
2919 s->memcg_params = kzalloc(size, GFP_KERNEL);
2920 if (!s->memcg_params)
2924 s->memcg_params->memcg = memcg;
2925 s->memcg_params->root_cache = root_cache;
2926 INIT_WORK(&s->memcg_params->destroy,
2927 kmem_cache_destroy_work_func);
2929 s->memcg_params->is_root_cache = true;
2934 void memcg_release_cache(struct kmem_cache *s)
2936 struct kmem_cache *root;
2937 struct mem_cgroup *memcg;
2941 * This happens, for instance, when a root cache goes away before we
2944 if (!s->memcg_params)
2947 if (s->memcg_params->is_root_cache)
2950 memcg = s->memcg_params->memcg;
2951 id = memcg_cache_id(memcg);
2953 root = s->memcg_params->root_cache;
2954 root->memcg_params->memcg_caches[id] = NULL;
2956 mutex_lock(&memcg->slab_caches_mutex);
2957 list_del(&s->memcg_params->list);
2958 mutex_unlock(&memcg->slab_caches_mutex);
2960 css_put(&memcg->css);
2962 kfree(s->memcg_params);
2966 * During the creation a new cache, we need to disable our accounting mechanism
2967 * altogether. This is true even if we are not creating, but rather just
2968 * enqueing new caches to be created.
2970 * This is because that process will trigger allocations; some visible, like
2971 * explicit kmallocs to auxiliary data structures, name strings and internal
2972 * cache structures; some well concealed, like INIT_WORK() that can allocate
2973 * objects during debug.
2975 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
2976 * to it. This may not be a bounded recursion: since the first cache creation
2977 * failed to complete (waiting on the allocation), we'll just try to create the
2978 * cache again, failing at the same point.
2980 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
2981 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
2982 * inside the following two functions.
2984 static inline void memcg_stop_kmem_account(void)
2986 VM_BUG_ON(!current->mm);
2987 current->memcg_kmem_skip_account++;
2990 static inline void memcg_resume_kmem_account(void)
2992 VM_BUG_ON(!current->mm);
2993 current->memcg_kmem_skip_account--;
2996 static void kmem_cache_destroy_work_func(struct work_struct *w)
2998 struct kmem_cache *cachep;
2999 struct memcg_cache_params *p;
3001 p = container_of(w, struct memcg_cache_params, destroy);
3003 cachep = memcg_params_to_cache(p);
3006 * If we get down to 0 after shrink, we could delete right away.
3007 * However, memcg_release_pages() already puts us back in the workqueue
3008 * in that case. If we proceed deleting, we'll get a dangling
3009 * reference, and removing the object from the workqueue in that case
3010 * is unnecessary complication. We are not a fast path.
3012 * Note that this case is fundamentally different from racing with
3013 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3014 * kmem_cache_shrink, not only we would be reinserting a dead cache
3015 * into the queue, but doing so from inside the worker racing to
3018 * So if we aren't down to zero, we'll just schedule a worker and try
3021 if (atomic_read(&cachep->memcg_params->nr_pages) != 0) {
3022 kmem_cache_shrink(cachep);
3023 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
3026 kmem_cache_destroy(cachep);
3029 void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
3031 if (!cachep->memcg_params->dead)
3035 * There are many ways in which we can get here.
3037 * We can get to a memory-pressure situation while the delayed work is
3038 * still pending to run. The vmscan shrinkers can then release all
3039 * cache memory and get us to destruction. If this is the case, we'll
3040 * be executed twice, which is a bug (the second time will execute over
3041 * bogus data). In this case, cancelling the work should be fine.
3043 * But we can also get here from the worker itself, if
3044 * kmem_cache_shrink is enough to shake all the remaining objects and
3045 * get the page count to 0. In this case, we'll deadlock if we try to
3046 * cancel the work (the worker runs with an internal lock held, which
3047 * is the same lock we would hold for cancel_work_sync().)
3049 * Since we can't possibly know who got us here, just refrain from
3050 * running if there is already work pending
3052 if (work_pending(&cachep->memcg_params->destroy))
3055 * We have to defer the actual destroying to a workqueue, because
3056 * we might currently be in a context that cannot sleep.
3058 schedule_work(&cachep->memcg_params->destroy);
3062 * This lock protects updaters, not readers. We want readers to be as fast as
3063 * they can, and they will either see NULL or a valid cache value. Our model
3064 * allow them to see NULL, in which case the root memcg will be selected.
3066 * We need this lock because multiple allocations to the same cache from a non
3067 * will span more than one worker. Only one of them can create the cache.
3069 static DEFINE_MUTEX(memcg_cache_mutex);
3072 * Called with memcg_cache_mutex held
3074 static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
3075 struct kmem_cache *s)
3077 struct kmem_cache *new;
3078 static char *tmp_name = NULL;
3080 lockdep_assert_held(&memcg_cache_mutex);
3083 * kmem_cache_create_memcg duplicates the given name and
3084 * cgroup_name for this name requires RCU context.
3085 * This static temporary buffer is used to prevent from
3086 * pointless shortliving allocation.
3089 tmp_name = kmalloc(PATH_MAX, GFP_KERNEL);
3095 snprintf(tmp_name, PATH_MAX, "%s(%d:%s)", s->name,
3096 memcg_cache_id(memcg), cgroup_name(memcg->css.cgroup));
3099 new = kmem_cache_create_memcg(memcg, tmp_name, s->object_size, s->align,
3100 (s->flags & ~SLAB_PANIC), s->ctor, s);
3103 new->allocflags |= __GFP_KMEMCG;
3108 static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
3109 struct kmem_cache *cachep)
3111 struct kmem_cache *new_cachep;
3114 BUG_ON(!memcg_can_account_kmem(memcg));
3116 idx = memcg_cache_id(memcg);
3118 mutex_lock(&memcg_cache_mutex);
3119 new_cachep = cachep->memcg_params->memcg_caches[idx];
3121 css_put(&memcg->css);
3125 new_cachep = kmem_cache_dup(memcg, cachep);
3126 if (new_cachep == NULL) {
3127 new_cachep = cachep;
3128 css_put(&memcg->css);
3132 atomic_set(&new_cachep->memcg_params->nr_pages , 0);
3134 cachep->memcg_params->memcg_caches[idx] = new_cachep;
3136 * the readers won't lock, make sure everybody sees the updated value,
3137 * so they won't put stuff in the queue again for no reason
3141 mutex_unlock(&memcg_cache_mutex);
3145 void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
3147 struct kmem_cache *c;
3150 if (!s->memcg_params)
3152 if (!s->memcg_params->is_root_cache)
3156 * If the cache is being destroyed, we trust that there is no one else
3157 * requesting objects from it. Even if there are, the sanity checks in
3158 * kmem_cache_destroy should caught this ill-case.
3160 * Still, we don't want anyone else freeing memcg_caches under our
3161 * noses, which can happen if a new memcg comes to life. As usual,
3162 * we'll take the set_limit_mutex to protect ourselves against this.
3164 mutex_lock(&set_limit_mutex);
3165 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3166 c = s->memcg_params->memcg_caches[i];
3171 * We will now manually delete the caches, so to avoid races
3172 * we need to cancel all pending destruction workers and
3173 * proceed with destruction ourselves.
3175 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3176 * and that could spawn the workers again: it is likely that
3177 * the cache still have active pages until this very moment.
3178 * This would lead us back to mem_cgroup_destroy_cache.
3180 * But that will not execute at all if the "dead" flag is not
3181 * set, so flip it down to guarantee we are in control.
3183 c->memcg_params->dead = false;
3184 cancel_work_sync(&c->memcg_params->destroy);
3185 kmem_cache_destroy(c);
3187 mutex_unlock(&set_limit_mutex);
3190 struct create_work {
3191 struct mem_cgroup *memcg;
3192 struct kmem_cache *cachep;
3193 struct work_struct work;
3196 static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3198 struct kmem_cache *cachep;
3199 struct memcg_cache_params *params;
3201 if (!memcg_kmem_is_active(memcg))
3204 mutex_lock(&memcg->slab_caches_mutex);
3205 list_for_each_entry(params, &memcg->memcg_slab_caches, list) {
3206 cachep = memcg_params_to_cache(params);
3207 cachep->memcg_params->dead = true;
3208 schedule_work(&cachep->memcg_params->destroy);
3210 mutex_unlock(&memcg->slab_caches_mutex);
3213 static void memcg_create_cache_work_func(struct work_struct *w)
3215 struct create_work *cw;
3217 cw = container_of(w, struct create_work, work);
3218 memcg_create_kmem_cache(cw->memcg, cw->cachep);
3223 * Enqueue the creation of a per-memcg kmem_cache.
3225 static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3226 struct kmem_cache *cachep)
3228 struct create_work *cw;
3230 cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT);
3232 css_put(&memcg->css);
3237 cw->cachep = cachep;
3239 INIT_WORK(&cw->work, memcg_create_cache_work_func);
3240 schedule_work(&cw->work);
3243 static void memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3244 struct kmem_cache *cachep)
3247 * We need to stop accounting when we kmalloc, because if the
3248 * corresponding kmalloc cache is not yet created, the first allocation
3249 * in __memcg_create_cache_enqueue will recurse.
3251 * However, it is better to enclose the whole function. Depending on
3252 * the debugging options enabled, INIT_WORK(), for instance, can
3253 * trigger an allocation. This too, will make us recurse. Because at
3254 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3255 * the safest choice is to do it like this, wrapping the whole function.
3257 memcg_stop_kmem_account();
3258 __memcg_create_cache_enqueue(memcg, cachep);
3259 memcg_resume_kmem_account();
3262 * Return the kmem_cache we're supposed to use for a slab allocation.
3263 * We try to use the current memcg's version of the cache.
3265 * If the cache does not exist yet, if we are the first user of it,
3266 * we either create it immediately, if possible, or create it asynchronously
3268 * In the latter case, we will let the current allocation go through with
3269 * the original cache.
3271 * Can't be called in interrupt context or from kernel threads.
3272 * This function needs to be called with rcu_read_lock() held.
3274 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3277 struct mem_cgroup *memcg;
3280 VM_BUG_ON(!cachep->memcg_params);
3281 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3283 if (!current->mm || current->memcg_kmem_skip_account)
3287 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3289 if (!memcg_can_account_kmem(memcg))
3292 idx = memcg_cache_id(memcg);
3295 * barrier to mare sure we're always seeing the up to date value. The
3296 * code updating memcg_caches will issue a write barrier to match this.
3298 read_barrier_depends();
3299 if (likely(cachep->memcg_params->memcg_caches[idx])) {
3300 cachep = cachep->memcg_params->memcg_caches[idx];
3304 /* The corresponding put will be done in the workqueue. */
3305 if (!css_tryget(&memcg->css))
3310 * If we are in a safe context (can wait, and not in interrupt
3311 * context), we could be be predictable and return right away.
3312 * This would guarantee that the allocation being performed
3313 * already belongs in the new cache.
3315 * However, there are some clashes that can arrive from locking.
3316 * For instance, because we acquire the slab_mutex while doing
3317 * kmem_cache_dup, this means no further allocation could happen
3318 * with the slab_mutex held.
3320 * Also, because cache creation issue get_online_cpus(), this
3321 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3322 * that ends up reversed during cpu hotplug. (cpuset allocates
3323 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3324 * better to defer everything.
3326 memcg_create_cache_enqueue(memcg, cachep);
3332 EXPORT_SYMBOL(__memcg_kmem_get_cache);
3335 * We need to verify if the allocation against current->mm->owner's memcg is
3336 * possible for the given order. But the page is not allocated yet, so we'll
3337 * need a further commit step to do the final arrangements.
3339 * It is possible for the task to switch cgroups in this mean time, so at
3340 * commit time, we can't rely on task conversion any longer. We'll then use
3341 * the handle argument to return to the caller which cgroup we should commit
3342 * against. We could also return the memcg directly and avoid the pointer
3343 * passing, but a boolean return value gives better semantics considering
3344 * the compiled-out case as well.
3346 * Returning true means the allocation is possible.
3349 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3351 struct mem_cgroup *memcg;
3357 * Disabling accounting is only relevant for some specific memcg
3358 * internal allocations. Therefore we would initially not have such
3359 * check here, since direct calls to the page allocator that are marked
3360 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3361 * concerned with cache allocations, and by having this test at
3362 * memcg_kmem_get_cache, we are already able to relay the allocation to
3363 * the root cache and bypass the memcg cache altogether.
3365 * There is one exception, though: the SLUB allocator does not create
3366 * large order caches, but rather service large kmallocs directly from
3367 * the page allocator. Therefore, the following sequence when backed by
3368 * the SLUB allocator:
3370 * memcg_stop_kmem_account();
3371 * kmalloc(<large_number>)
3372 * memcg_resume_kmem_account();
3374 * would effectively ignore the fact that we should skip accounting,
3375 * since it will drive us directly to this function without passing
3376 * through the cache selector memcg_kmem_get_cache. Such large
3377 * allocations are extremely rare but can happen, for instance, for the
3378 * cache arrays. We bring this test here.
3380 if (!current->mm || current->memcg_kmem_skip_account)
3383 memcg = try_get_mem_cgroup_from_mm(current->mm);
3386 * very rare case described in mem_cgroup_from_task. Unfortunately there
3387 * isn't much we can do without complicating this too much, and it would
3388 * be gfp-dependent anyway. Just let it go
3390 if (unlikely(!memcg))
3393 if (!memcg_can_account_kmem(memcg)) {
3394 css_put(&memcg->css);
3398 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3402 css_put(&memcg->css);
3406 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3409 struct page_cgroup *pc;
3411 VM_BUG_ON(mem_cgroup_is_root(memcg));
3413 /* The page allocation failed. Revert */
3415 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3419 pc = lookup_page_cgroup(page);
3420 lock_page_cgroup(pc);
3421 pc->mem_cgroup = memcg;
3422 SetPageCgroupUsed(pc);
3423 unlock_page_cgroup(pc);
3426 void __memcg_kmem_uncharge_pages(struct page *page, int order)
3428 struct mem_cgroup *memcg = NULL;
3429 struct page_cgroup *pc;
3432 pc = lookup_page_cgroup(page);
3434 * Fast unlocked return. Theoretically might have changed, have to
3435 * check again after locking.
3437 if (!PageCgroupUsed(pc))
3440 lock_page_cgroup(pc);
3441 if (PageCgroupUsed(pc)) {
3442 memcg = pc->mem_cgroup;
3443 ClearPageCgroupUsed(pc);
3445 unlock_page_cgroup(pc);
3448 * We trust that only if there is a memcg associated with the page, it
3449 * is a valid allocation
3454 VM_BUG_ON(mem_cgroup_is_root(memcg));
3455 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3458 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3461 #endif /* CONFIG_MEMCG_KMEM */
3463 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3465 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3467 * Because tail pages are not marked as "used", set it. We're under
3468 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3469 * charge/uncharge will be never happen and move_account() is done under
3470 * compound_lock(), so we don't have to take care of races.
3472 void mem_cgroup_split_huge_fixup(struct page *head)
3474 struct page_cgroup *head_pc = lookup_page_cgroup(head);
3475 struct page_cgroup *pc;
3476 struct mem_cgroup *memcg;
3479 if (mem_cgroup_disabled())
3482 memcg = head_pc->mem_cgroup;
3483 for (i = 1; i < HPAGE_PMD_NR; i++) {
3485 pc->mem_cgroup = memcg;
3486 smp_wmb();/* see __commit_charge() */
3487 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3489 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3492 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3495 * mem_cgroup_move_account - move account of the page
3497 * @nr_pages: number of regular pages (>1 for huge pages)
3498 * @pc: page_cgroup of the page.
3499 * @from: mem_cgroup which the page is moved from.
3500 * @to: mem_cgroup which the page is moved to. @from != @to.
3502 * The caller must confirm following.
3503 * - page is not on LRU (isolate_page() is useful.)
3504 * - compound_lock is held when nr_pages > 1
3506 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3509 static int mem_cgroup_move_account(struct page *page,
3510 unsigned int nr_pages,
3511 struct page_cgroup *pc,
3512 struct mem_cgroup *from,
3513 struct mem_cgroup *to)
3515 unsigned long flags;
3517 bool anon = PageAnon(page);
3519 VM_BUG_ON(from == to);
3520 VM_BUG_ON(PageLRU(page));
3522 * The page is isolated from LRU. So, collapse function
3523 * will not handle this page. But page splitting can happen.
3524 * Do this check under compound_page_lock(). The caller should
3528 if (nr_pages > 1 && !PageTransHuge(page))
3531 lock_page_cgroup(pc);
3534 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3537 move_lock_mem_cgroup(from, &flags);
3539 if (!anon && page_mapped(page)) {
3540 /* Update mapped_file data for mem_cgroup */
3542 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3543 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3546 mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
3548 /* caller should have done css_get */
3549 pc->mem_cgroup = to;
3550 mem_cgroup_charge_statistics(to, page, anon, nr_pages);
3551 move_unlock_mem_cgroup(from, &flags);
3554 unlock_page_cgroup(pc);
3558 memcg_check_events(to, page);
3559 memcg_check_events(from, page);
3565 * mem_cgroup_move_parent - moves page to the parent group
3566 * @page: the page to move
3567 * @pc: page_cgroup of the page
3568 * @child: page's cgroup
3570 * move charges to its parent or the root cgroup if the group has no
3571 * parent (aka use_hierarchy==0).
3572 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3573 * mem_cgroup_move_account fails) the failure is always temporary and
3574 * it signals a race with a page removal/uncharge or migration. In the
3575 * first case the page is on the way out and it will vanish from the LRU
3576 * on the next attempt and the call should be retried later.
3577 * Isolation from the LRU fails only if page has been isolated from
3578 * the LRU since we looked at it and that usually means either global
3579 * reclaim or migration going on. The page will either get back to the
3581 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3582 * (!PageCgroupUsed) or moved to a different group. The page will
3583 * disappear in the next attempt.
3585 static int mem_cgroup_move_parent(struct page *page,
3586 struct page_cgroup *pc,
3587 struct mem_cgroup *child)
3589 struct mem_cgroup *parent;
3590 unsigned int nr_pages;
3591 unsigned long uninitialized_var(flags);
3594 VM_BUG_ON(mem_cgroup_is_root(child));
3597 if (!get_page_unless_zero(page))
3599 if (isolate_lru_page(page))
3602 nr_pages = hpage_nr_pages(page);
3604 parent = parent_mem_cgroup(child);
3606 * If no parent, move charges to root cgroup.
3609 parent = root_mem_cgroup;
3612 VM_BUG_ON(!PageTransHuge(page));
3613 flags = compound_lock_irqsave(page);
3616 ret = mem_cgroup_move_account(page, nr_pages,
3619 __mem_cgroup_cancel_local_charge(child, nr_pages);
3622 compound_unlock_irqrestore(page, flags);
3623 putback_lru_page(page);
3631 * Charge the memory controller for page usage.
3633 * 0 if the charge was successful
3634 * < 0 if the cgroup is over its limit
3636 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
3637 gfp_t gfp_mask, enum charge_type ctype)
3639 struct mem_cgroup *memcg = NULL;
3640 unsigned int nr_pages = 1;
3644 if (PageTransHuge(page)) {
3645 nr_pages <<= compound_order(page);
3646 VM_BUG_ON(!PageTransHuge(page));
3648 * Never OOM-kill a process for a huge page. The
3649 * fault handler will fall back to regular pages.
3654 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
3657 __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
3661 int mem_cgroup_newpage_charge(struct page *page,
3662 struct mm_struct *mm, gfp_t gfp_mask)
3664 if (mem_cgroup_disabled())
3666 VM_BUG_ON(page_mapped(page));
3667 VM_BUG_ON(page->mapping && !PageAnon(page));
3669 return mem_cgroup_charge_common(page, mm, gfp_mask,
3670 MEM_CGROUP_CHARGE_TYPE_ANON);
3674 * While swap-in, try_charge -> commit or cancel, the page is locked.
3675 * And when try_charge() successfully returns, one refcnt to memcg without
3676 * struct page_cgroup is acquired. This refcnt will be consumed by
3677 * "commit()" or removed by "cancel()"
3679 static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3682 struct mem_cgroup **memcgp)
3684 struct mem_cgroup *memcg;
3685 struct page_cgroup *pc;
3688 pc = lookup_page_cgroup(page);
3690 * Every swap fault against a single page tries to charge the
3691 * page, bail as early as possible. shmem_unuse() encounters
3692 * already charged pages, too. The USED bit is protected by
3693 * the page lock, which serializes swap cache removal, which
3694 * in turn serializes uncharging.
3696 if (PageCgroupUsed(pc))
3698 if (!do_swap_account)
3700 memcg = try_get_mem_cgroup_from_page(page);
3704 ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
3705 css_put(&memcg->css);
3710 ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
3716 int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3717 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3720 if (mem_cgroup_disabled())
3723 * A racing thread's fault, or swapoff, may have already
3724 * updated the pte, and even removed page from swap cache: in
3725 * those cases unuse_pte()'s pte_same() test will fail; but
3726 * there's also a KSM case which does need to charge the page.
3728 if (!PageSwapCache(page)) {
3731 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true);
3736 return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3739 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3741 if (mem_cgroup_disabled())
3745 __mem_cgroup_cancel_charge(memcg, 1);
3749 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
3750 enum charge_type ctype)
3752 if (mem_cgroup_disabled())
3757 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
3759 * Now swap is on-memory. This means this page may be
3760 * counted both as mem and swap....double count.
3761 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3762 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3763 * may call delete_from_swap_cache() before reach here.
3765 if (do_swap_account && PageSwapCache(page)) {
3766 swp_entry_t ent = {.val = page_private(page)};
3767 mem_cgroup_uncharge_swap(ent);
3771 void mem_cgroup_commit_charge_swapin(struct page *page,
3772 struct mem_cgroup *memcg)
3774 __mem_cgroup_commit_charge_swapin(page, memcg,
3775 MEM_CGROUP_CHARGE_TYPE_ANON);
3778 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
3781 struct mem_cgroup *memcg = NULL;
3782 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3785 if (mem_cgroup_disabled())
3787 if (PageCompound(page))
3790 if (!PageSwapCache(page))
3791 ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
3792 else { /* page is swapcache/shmem */
3793 ret = __mem_cgroup_try_charge_swapin(mm, page,
3796 __mem_cgroup_commit_charge_swapin(page, memcg, type);
3801 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
3802 unsigned int nr_pages,
3803 const enum charge_type ctype)
3805 struct memcg_batch_info *batch = NULL;
3806 bool uncharge_memsw = true;
3808 /* If swapout, usage of swap doesn't decrease */
3809 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3810 uncharge_memsw = false;
3812 batch = ¤t->memcg_batch;
3814 * In usual, we do css_get() when we remember memcg pointer.
3815 * But in this case, we keep res->usage until end of a series of
3816 * uncharges. Then, it's ok to ignore memcg's refcnt.
3819 batch->memcg = memcg;
3821 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3822 * In those cases, all pages freed continuously can be expected to be in
3823 * the same cgroup and we have chance to coalesce uncharges.
3824 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3825 * because we want to do uncharge as soon as possible.
3828 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
3829 goto direct_uncharge;
3832 goto direct_uncharge;
3835 * In typical case, batch->memcg == mem. This means we can
3836 * merge a series of uncharges to an uncharge of res_counter.
3837 * If not, we uncharge res_counter ony by one.
3839 if (batch->memcg != memcg)
3840 goto direct_uncharge;
3841 /* remember freed charge and uncharge it later */
3844 batch->memsw_nr_pages++;
3847 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
3849 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
3850 if (unlikely(batch->memcg != memcg))
3851 memcg_oom_recover(memcg);
3855 * uncharge if !page_mapped(page)
3857 static struct mem_cgroup *
3858 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
3861 struct mem_cgroup *memcg = NULL;
3862 unsigned int nr_pages = 1;
3863 struct page_cgroup *pc;
3866 if (mem_cgroup_disabled())
3869 if (PageTransHuge(page)) {
3870 nr_pages <<= compound_order(page);
3871 VM_BUG_ON(!PageTransHuge(page));
3874 * Check if our page_cgroup is valid
3876 pc = lookup_page_cgroup(page);
3877 if (unlikely(!PageCgroupUsed(pc)))
3880 lock_page_cgroup(pc);
3882 memcg = pc->mem_cgroup;
3884 if (!PageCgroupUsed(pc))
3887 anon = PageAnon(page);
3890 case MEM_CGROUP_CHARGE_TYPE_ANON:
3892 * Generally PageAnon tells if it's the anon statistics to be
3893 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3894 * used before page reached the stage of being marked PageAnon.
3898 case MEM_CGROUP_CHARGE_TYPE_DROP:
3899 /* See mem_cgroup_prepare_migration() */
3900 if (page_mapped(page))
3903 * Pages under migration may not be uncharged. But
3904 * end_migration() /must/ be the one uncharging the
3905 * unused post-migration page and so it has to call
3906 * here with the migration bit still set. See the
3907 * res_counter handling below.
3909 if (!end_migration && PageCgroupMigration(pc))
3912 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3913 if (!PageAnon(page)) { /* Shared memory */
3914 if (page->mapping && !page_is_file_cache(page))
3916 } else if (page_mapped(page)) /* Anon */
3923 mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
3925 ClearPageCgroupUsed(pc);
3927 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3928 * freed from LRU. This is safe because uncharged page is expected not
3929 * to be reused (freed soon). Exception is SwapCache, it's handled by
3930 * special functions.
3933 unlock_page_cgroup(pc);
3935 * even after unlock, we have memcg->res.usage here and this memcg
3936 * will never be freed, so it's safe to call css_get().
3938 memcg_check_events(memcg, page);
3939 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3940 mem_cgroup_swap_statistics(memcg, true);
3941 css_get(&memcg->css);
3944 * Migration does not charge the res_counter for the
3945 * replacement page, so leave it alone when phasing out the
3946 * page that is unused after the migration.
3948 if (!end_migration && !mem_cgroup_is_root(memcg))
3949 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
3954 unlock_page_cgroup(pc);
3958 void mem_cgroup_uncharge_page(struct page *page)
3961 if (page_mapped(page))
3963 VM_BUG_ON(page->mapping && !PageAnon(page));
3965 * If the page is in swap cache, uncharge should be deferred
3966 * to the swap path, which also properly accounts swap usage
3967 * and handles memcg lifetime.
3969 * Note that this check is not stable and reclaim may add the
3970 * page to swap cache at any time after this. However, if the
3971 * page is not in swap cache by the time page->mapcount hits
3972 * 0, there won't be any page table references to the swap
3973 * slot, and reclaim will free it and not actually write the
3976 if (PageSwapCache(page))
3978 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
3981 void mem_cgroup_uncharge_cache_page(struct page *page)
3983 VM_BUG_ON(page_mapped(page));
3984 VM_BUG_ON(page->mapping);
3985 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
3989 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3990 * In that cases, pages are freed continuously and we can expect pages
3991 * are in the same memcg. All these calls itself limits the number of
3992 * pages freed at once, then uncharge_start/end() is called properly.
3993 * This may be called prural(2) times in a context,
3996 void mem_cgroup_uncharge_start(void)
3998 current->memcg_batch.do_batch++;
3999 /* We can do nest. */
4000 if (current->memcg_batch.do_batch == 1) {
4001 current->memcg_batch.memcg = NULL;
4002 current->memcg_batch.nr_pages = 0;
4003 current->memcg_batch.memsw_nr_pages = 0;
4007 void mem_cgroup_uncharge_end(void)
4009 struct memcg_batch_info *batch = ¤t->memcg_batch;
4011 if (!batch->do_batch)
4015 if (batch->do_batch) /* If stacked, do nothing. */
4021 * This "batch->memcg" is valid without any css_get/put etc...
4022 * bacause we hide charges behind us.
4024 if (batch->nr_pages)
4025 res_counter_uncharge(&batch->memcg->res,
4026 batch->nr_pages * PAGE_SIZE);
4027 if (batch->memsw_nr_pages)
4028 res_counter_uncharge(&batch->memcg->memsw,
4029 batch->memsw_nr_pages * PAGE_SIZE);
4030 memcg_oom_recover(batch->memcg);
4031 /* forget this pointer (for sanity check) */
4032 batch->memcg = NULL;
4037 * called after __delete_from_swap_cache() and drop "page" account.
4038 * memcg information is recorded to swap_cgroup of "ent"
4041 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
4043 struct mem_cgroup *memcg;
4044 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4046 if (!swapout) /* this was a swap cache but the swap is unused ! */
4047 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4049 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
4052 * record memcg information, if swapout && memcg != NULL,
4053 * css_get() was called in uncharge().
4055 if (do_swap_account && swapout && memcg)
4056 swap_cgroup_record(ent, css_id(&memcg->css));
4060 #ifdef CONFIG_MEMCG_SWAP
4062 * called from swap_entry_free(). remove record in swap_cgroup and
4063 * uncharge "memsw" account.
4065 void mem_cgroup_uncharge_swap(swp_entry_t ent)
4067 struct mem_cgroup *memcg;
4070 if (!do_swap_account)
4073 id = swap_cgroup_record(ent, 0);
4075 memcg = mem_cgroup_lookup(id);
4078 * We uncharge this because swap is freed.
4079 * This memcg can be obsolete one. We avoid calling css_tryget
4081 if (!mem_cgroup_is_root(memcg))
4082 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
4083 mem_cgroup_swap_statistics(memcg, false);
4084 css_put(&memcg->css);
4090 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4091 * @entry: swap entry to be moved
4092 * @from: mem_cgroup which the entry is moved from
4093 * @to: mem_cgroup which the entry is moved to
4095 * It succeeds only when the swap_cgroup's record for this entry is the same
4096 * as the mem_cgroup's id of @from.
4098 * Returns 0 on success, -EINVAL on failure.
4100 * The caller must have charged to @to, IOW, called res_counter_charge() about
4101 * both res and memsw, and called css_get().
4103 static int mem_cgroup_move_swap_account(swp_entry_t entry,
4104 struct mem_cgroup *from, struct mem_cgroup *to)
4106 unsigned short old_id, new_id;
4108 old_id = css_id(&from->css);
4109 new_id = css_id(&to->css);
4111 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
4112 mem_cgroup_swap_statistics(from, false);
4113 mem_cgroup_swap_statistics(to, true);
4115 * This function is only called from task migration context now.
4116 * It postpones res_counter and refcount handling till the end
4117 * of task migration(mem_cgroup_clear_mc()) for performance
4118 * improvement. But we cannot postpone css_get(to) because if
4119 * the process that has been moved to @to does swap-in, the
4120 * refcount of @to might be decreased to 0.
4122 * We are in attach() phase, so the cgroup is guaranteed to be
4123 * alive, so we can just call css_get().
4131 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
4132 struct mem_cgroup *from, struct mem_cgroup *to)
4139 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4142 void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4143 struct mem_cgroup **memcgp)
4145 struct mem_cgroup *memcg = NULL;
4146 unsigned int nr_pages = 1;
4147 struct page_cgroup *pc;
4148 enum charge_type ctype;
4152 if (mem_cgroup_disabled())
4155 if (PageTransHuge(page))
4156 nr_pages <<= compound_order(page);
4158 pc = lookup_page_cgroup(page);
4159 lock_page_cgroup(pc);
4160 if (PageCgroupUsed(pc)) {
4161 memcg = pc->mem_cgroup;
4162 css_get(&memcg->css);
4164 * At migrating an anonymous page, its mapcount goes down
4165 * to 0 and uncharge() will be called. But, even if it's fully
4166 * unmapped, migration may fail and this page has to be
4167 * charged again. We set MIGRATION flag here and delay uncharge
4168 * until end_migration() is called
4170 * Corner Case Thinking
4172 * When the old page was mapped as Anon and it's unmap-and-freed
4173 * while migration was ongoing.
4174 * If unmap finds the old page, uncharge() of it will be delayed
4175 * until end_migration(). If unmap finds a new page, it's
4176 * uncharged when it make mapcount to be 1->0. If unmap code
4177 * finds swap_migration_entry, the new page will not be mapped
4178 * and end_migration() will find it(mapcount==0).
4181 * When the old page was mapped but migraion fails, the kernel
4182 * remaps it. A charge for it is kept by MIGRATION flag even
4183 * if mapcount goes down to 0. We can do remap successfully
4184 * without charging it again.
4187 * The "old" page is under lock_page() until the end of
4188 * migration, so, the old page itself will not be swapped-out.
4189 * If the new page is swapped out before end_migraton, our
4190 * hook to usual swap-out path will catch the event.
4193 SetPageCgroupMigration(pc);
4195 unlock_page_cgroup(pc);
4197 * If the page is not charged at this point,
4205 * We charge new page before it's used/mapped. So, even if unlock_page()
4206 * is called before end_migration, we can catch all events on this new
4207 * page. In the case new page is migrated but not remapped, new page's
4208 * mapcount will be finally 0 and we call uncharge in end_migration().
4211 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
4213 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
4215 * The page is committed to the memcg, but it's not actually
4216 * charged to the res_counter since we plan on replacing the
4217 * old one and only one page is going to be left afterwards.
4219 __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
4222 /* remove redundant charge if migration failed*/
4223 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
4224 struct page *oldpage, struct page *newpage, bool migration_ok)
4226 struct page *used, *unused;
4227 struct page_cgroup *pc;
4233 if (!migration_ok) {
4240 anon = PageAnon(used);
4241 __mem_cgroup_uncharge_common(unused,
4242 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4243 : MEM_CGROUP_CHARGE_TYPE_CACHE,
4245 css_put(&memcg->css);
4247 * We disallowed uncharge of pages under migration because mapcount
4248 * of the page goes down to zero, temporarly.
4249 * Clear the flag and check the page should be charged.
4251 pc = lookup_page_cgroup(oldpage);
4252 lock_page_cgroup(pc);
4253 ClearPageCgroupMigration(pc);
4254 unlock_page_cgroup(pc);
4257 * If a page is a file cache, radix-tree replacement is very atomic
4258 * and we can skip this check. When it was an Anon page, its mapcount
4259 * goes down to 0. But because we added MIGRATION flage, it's not
4260 * uncharged yet. There are several case but page->mapcount check
4261 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4262 * check. (see prepare_charge() also)
4265 mem_cgroup_uncharge_page(used);
4269 * At replace page cache, newpage is not under any memcg but it's on
4270 * LRU. So, this function doesn't touch res_counter but handles LRU
4271 * in correct way. Both pages are locked so we cannot race with uncharge.
4273 void mem_cgroup_replace_page_cache(struct page *oldpage,
4274 struct page *newpage)
4276 struct mem_cgroup *memcg = NULL;
4277 struct page_cgroup *pc;
4278 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
4280 if (mem_cgroup_disabled())
4283 pc = lookup_page_cgroup(oldpage);
4284 /* fix accounting on old pages */
4285 lock_page_cgroup(pc);
4286 if (PageCgroupUsed(pc)) {
4287 memcg = pc->mem_cgroup;
4288 mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
4289 ClearPageCgroupUsed(pc);
4291 unlock_page_cgroup(pc);
4294 * When called from shmem_replace_page(), in some cases the
4295 * oldpage has already been charged, and in some cases not.
4300 * Even if newpage->mapping was NULL before starting replacement,
4301 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4302 * LRU while we overwrite pc->mem_cgroup.
4304 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
4307 #ifdef CONFIG_DEBUG_VM
4308 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4310 struct page_cgroup *pc;
4312 pc = lookup_page_cgroup(page);
4314 * Can be NULL while feeding pages into the page allocator for
4315 * the first time, i.e. during boot or memory hotplug;
4316 * or when mem_cgroup_disabled().
4318 if (likely(pc) && PageCgroupUsed(pc))
4323 bool mem_cgroup_bad_page_check(struct page *page)
4325 if (mem_cgroup_disabled())
4328 return lookup_page_cgroup_used(page) != NULL;
4331 void mem_cgroup_print_bad_page(struct page *page)
4333 struct page_cgroup *pc;
4335 pc = lookup_page_cgroup_used(page);
4337 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4338 pc, pc->flags, pc->mem_cgroup);
4343 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
4344 unsigned long long val)
4347 u64 memswlimit, memlimit;
4349 int children = mem_cgroup_count_children(memcg);
4350 u64 curusage, oldusage;
4354 * For keeping hierarchical_reclaim simple, how long we should retry
4355 * is depends on callers. We set our retry-count to be function
4356 * of # of children which we should visit in this loop.
4358 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4360 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4363 while (retry_count) {
4364 if (signal_pending(current)) {
4369 * Rather than hide all in some function, I do this in
4370 * open coded manner. You see what this really does.
4371 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4373 mutex_lock(&set_limit_mutex);
4374 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4375 if (memswlimit < val) {
4377 mutex_unlock(&set_limit_mutex);
4381 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4385 ret = res_counter_set_limit(&memcg->res, val);
4387 if (memswlimit == val)
4388 memcg->memsw_is_minimum = true;
4390 memcg->memsw_is_minimum = false;
4392 mutex_unlock(&set_limit_mutex);
4397 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4398 MEM_CGROUP_RECLAIM_SHRINK);
4399 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4400 /* Usage is reduced ? */
4401 if (curusage >= oldusage)
4404 oldusage = curusage;
4406 if (!ret && enlarge)
4407 memcg_oom_recover(memcg);
4412 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4413 unsigned long long val)
4416 u64 memlimit, memswlimit, oldusage, curusage;
4417 int children = mem_cgroup_count_children(memcg);
4421 /* see mem_cgroup_resize_res_limit */
4422 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
4423 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4424 while (retry_count) {
4425 if (signal_pending(current)) {
4430 * Rather than hide all in some function, I do this in
4431 * open coded manner. You see what this really does.
4432 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4434 mutex_lock(&set_limit_mutex);
4435 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4436 if (memlimit > val) {
4438 mutex_unlock(&set_limit_mutex);
4441 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4442 if (memswlimit < val)
4444 ret = res_counter_set_limit(&memcg->memsw, val);
4446 if (memlimit == val)
4447 memcg->memsw_is_minimum = true;
4449 memcg->memsw_is_minimum = false;
4451 mutex_unlock(&set_limit_mutex);
4456 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4457 MEM_CGROUP_RECLAIM_NOSWAP |
4458 MEM_CGROUP_RECLAIM_SHRINK);
4459 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4460 /* Usage is reduced ? */
4461 if (curusage >= oldusage)
4464 oldusage = curusage;
4466 if (!ret && enlarge)
4467 memcg_oom_recover(memcg);
4472 * mem_cgroup_force_empty_list - clears LRU of a group
4473 * @memcg: group to clear
4476 * @lru: lru to to clear
4478 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4479 * reclaim the pages page themselves - pages are moved to the parent (or root)
4482 static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
4483 int node, int zid, enum lru_list lru)
4485 struct lruvec *lruvec;
4486 unsigned long flags;
4487 struct list_head *list;
4491 zone = &NODE_DATA(node)->node_zones[zid];
4492 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4493 list = &lruvec->lists[lru];
4497 struct page_cgroup *pc;
4500 spin_lock_irqsave(&zone->lru_lock, flags);
4501 if (list_empty(list)) {
4502 spin_unlock_irqrestore(&zone->lru_lock, flags);
4505 page = list_entry(list->prev, struct page, lru);
4507 list_move(&page->lru, list);
4509 spin_unlock_irqrestore(&zone->lru_lock, flags);
4512 spin_unlock_irqrestore(&zone->lru_lock, flags);
4514 pc = lookup_page_cgroup(page);
4516 if (mem_cgroup_move_parent(page, pc, memcg)) {
4517 /* found lock contention or "pc" is obsolete. */
4522 } while (!list_empty(list));
4526 * make mem_cgroup's charge to be 0 if there is no task by moving
4527 * all the charges and pages to the parent.
4528 * This enables deleting this mem_cgroup.
4530 * Caller is responsible for holding css reference on the memcg.
4532 static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
4538 /* This is for making all *used* pages to be on LRU. */
4539 lru_add_drain_all();
4540 drain_all_stock_sync(memcg);
4541 mem_cgroup_start_move(memcg);
4542 for_each_node_state(node, N_MEMORY) {
4543 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4546 mem_cgroup_force_empty_list(memcg,
4551 mem_cgroup_end_move(memcg);
4552 memcg_oom_recover(memcg);
4556 * Kernel memory may not necessarily be trackable to a specific
4557 * process. So they are not migrated, and therefore we can't
4558 * expect their value to drop to 0 here.
4559 * Having res filled up with kmem only is enough.
4561 * This is a safety check because mem_cgroup_force_empty_list
4562 * could have raced with mem_cgroup_replace_page_cache callers
4563 * so the lru seemed empty but the page could have been added
4564 * right after the check. RES_USAGE should be safe as we always
4565 * charge before adding to the LRU.
4567 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4568 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4569 } while (usage > 0);
4573 * This mainly exists for tests during the setting of set of use_hierarchy.
4574 * Since this is the very setting we are changing, the current hierarchy value
4577 static inline bool __memcg_has_children(struct mem_cgroup *memcg)
4579 struct cgroup_subsys_state *pos;
4581 /* bounce at first found */
4582 css_for_each_child(pos, &memcg->css)
4588 * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed
4589 * to be already dead (as in mem_cgroup_force_empty, for instance). This is
4590 * from mem_cgroup_count_children(), in the sense that we don't really care how
4591 * many children we have; we only need to know if we have any. It also counts
4592 * any memcg without hierarchy as infertile.
4594 static inline bool memcg_has_children(struct mem_cgroup *memcg)
4596 return memcg->use_hierarchy && __memcg_has_children(memcg);
4600 * Reclaims as many pages from the given memcg as possible and moves
4601 * the rest to the parent.
4603 * Caller is responsible for holding css reference for memcg.
4605 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4607 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4608 struct cgroup *cgrp = memcg->css.cgroup;
4610 /* returns EBUSY if there is a task or if we come here twice. */
4611 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
4614 /* we call try-to-free pages for make this cgroup empty */
4615 lru_add_drain_all();
4616 /* try to free all pages in this cgroup */
4617 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4620 if (signal_pending(current))
4623 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4627 /* maybe some writeback is necessary */
4628 congestion_wait(BLK_RW_ASYNC, HZ/10);
4633 mem_cgroup_reparent_charges(memcg);
4638 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state *css,
4641 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4643 if (mem_cgroup_is_root(memcg))
4645 return mem_cgroup_force_empty(memcg);
4648 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4651 return mem_cgroup_from_css(css)->use_hierarchy;
4654 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4655 struct cftype *cft, u64 val)
4658 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4659 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(css_parent(&memcg->css));
4661 mutex_lock(&memcg_create_mutex);
4663 if (memcg->use_hierarchy == val)
4667 * If parent's use_hierarchy is set, we can't make any modifications
4668 * in the child subtrees. If it is unset, then the change can
4669 * occur, provided the current cgroup has no children.
4671 * For the root cgroup, parent_mem is NULL, we allow value to be
4672 * set if there are no children.
4674 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4675 (val == 1 || val == 0)) {
4676 if (!__memcg_has_children(memcg))
4677 memcg->use_hierarchy = val;
4684 mutex_unlock(&memcg_create_mutex);
4690 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
4691 enum mem_cgroup_stat_index idx)
4693 struct mem_cgroup *iter;
4696 /* Per-cpu values can be negative, use a signed accumulator */
4697 for_each_mem_cgroup_tree(iter, memcg)
4698 val += mem_cgroup_read_stat(iter, idx);
4700 if (val < 0) /* race ? */
4705 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
4709 if (!mem_cgroup_is_root(memcg)) {
4711 return res_counter_read_u64(&memcg->res, RES_USAGE);
4713 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
4717 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4718 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4720 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4721 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
4724 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
4726 return val << PAGE_SHIFT;
4729 static ssize_t mem_cgroup_read(struct cgroup_subsys_state *css,
4730 struct cftype *cft, struct file *file,
4731 char __user *buf, size_t nbytes, loff_t *ppos)
4733 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4739 type = MEMFILE_TYPE(cft->private);
4740 name = MEMFILE_ATTR(cft->private);
4744 if (name == RES_USAGE)
4745 val = mem_cgroup_usage(memcg, false);
4747 val = res_counter_read_u64(&memcg->res, name);
4750 if (name == RES_USAGE)
4751 val = mem_cgroup_usage(memcg, true);
4753 val = res_counter_read_u64(&memcg->memsw, name);
4756 val = res_counter_read_u64(&memcg->kmem, name);
4762 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
4763 return simple_read_from_buffer(buf, nbytes, ppos, str, len);
4766 static int memcg_update_kmem_limit(struct cgroup_subsys_state *css, u64 val)
4769 #ifdef CONFIG_MEMCG_KMEM
4770 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4772 * For simplicity, we won't allow this to be disabled. It also can't
4773 * be changed if the cgroup has children already, or if tasks had
4776 * If tasks join before we set the limit, a person looking at
4777 * kmem.usage_in_bytes will have no way to determine when it took
4778 * place, which makes the value quite meaningless.
4780 * After it first became limited, changes in the value of the limit are
4781 * of course permitted.
4783 mutex_lock(&memcg_create_mutex);
4784 mutex_lock(&set_limit_mutex);
4785 if (!memcg->kmem_account_flags && val != RESOURCE_MAX) {
4786 if (cgroup_task_count(css->cgroup) || memcg_has_children(memcg)) {
4790 ret = res_counter_set_limit(&memcg->kmem, val);
4793 ret = memcg_update_cache_sizes(memcg);
4795 res_counter_set_limit(&memcg->kmem, RESOURCE_MAX);
4798 static_key_slow_inc(&memcg_kmem_enabled_key);
4800 * setting the active bit after the inc will guarantee no one
4801 * starts accounting before all call sites are patched
4803 memcg_kmem_set_active(memcg);
4805 ret = res_counter_set_limit(&memcg->kmem, val);
4807 mutex_unlock(&set_limit_mutex);
4808 mutex_unlock(&memcg_create_mutex);
4813 #ifdef CONFIG_MEMCG_KMEM
4814 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
4817 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4821 memcg->kmem_account_flags = parent->kmem_account_flags;
4823 * When that happen, we need to disable the static branch only on those
4824 * memcgs that enabled it. To achieve this, we would be forced to
4825 * complicate the code by keeping track of which memcgs were the ones
4826 * that actually enabled limits, and which ones got it from its
4829 * It is a lot simpler just to do static_key_slow_inc() on every child
4830 * that is accounted.
4832 if (!memcg_kmem_is_active(memcg))
4836 * __mem_cgroup_free() will issue static_key_slow_dec() because this
4837 * memcg is active already. If the later initialization fails then the
4838 * cgroup core triggers the cleanup so we do not have to do it here.
4840 static_key_slow_inc(&memcg_kmem_enabled_key);
4842 mutex_lock(&set_limit_mutex);
4843 memcg_stop_kmem_account();
4844 ret = memcg_update_cache_sizes(memcg);
4845 memcg_resume_kmem_account();
4846 mutex_unlock(&set_limit_mutex);
4850 #endif /* CONFIG_MEMCG_KMEM */
4853 * The user of this function is...
4856 static int mem_cgroup_write(struct cgroup_subsys_state *css, struct cftype *cft,
4859 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4862 unsigned long long val;
4865 type = MEMFILE_TYPE(cft->private);
4866 name = MEMFILE_ATTR(cft->private);
4870 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
4874 /* This function does all necessary parse...reuse it */
4875 ret = res_counter_memparse_write_strategy(buffer, &val);
4879 ret = mem_cgroup_resize_limit(memcg, val);
4880 else if (type == _MEMSWAP)
4881 ret = mem_cgroup_resize_memsw_limit(memcg, val);
4882 else if (type == _KMEM)
4883 ret = memcg_update_kmem_limit(css, val);
4887 case RES_SOFT_LIMIT:
4888 ret = res_counter_memparse_write_strategy(buffer, &val);
4892 * For memsw, soft limits are hard to implement in terms
4893 * of semantics, for now, we support soft limits for
4894 * control without swap
4897 ret = res_counter_set_soft_limit(&memcg->res, val);
4902 ret = -EINVAL; /* should be BUG() ? */
4908 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
4909 unsigned long long *mem_limit, unsigned long long *memsw_limit)
4911 unsigned long long min_limit, min_memsw_limit, tmp;
4913 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4914 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4915 if (!memcg->use_hierarchy)
4918 while (css_parent(&memcg->css)) {
4919 memcg = mem_cgroup_from_css(css_parent(&memcg->css));
4920 if (!memcg->use_hierarchy)
4922 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
4923 min_limit = min(min_limit, tmp);
4924 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4925 min_memsw_limit = min(min_memsw_limit, tmp);
4928 *mem_limit = min_limit;
4929 *memsw_limit = min_memsw_limit;
4932 static int mem_cgroup_reset(struct cgroup_subsys_state *css, unsigned int event)
4934 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4938 type = MEMFILE_TYPE(event);
4939 name = MEMFILE_ATTR(event);
4944 res_counter_reset_max(&memcg->res);
4945 else if (type == _MEMSWAP)
4946 res_counter_reset_max(&memcg->memsw);
4947 else if (type == _KMEM)
4948 res_counter_reset_max(&memcg->kmem);
4954 res_counter_reset_failcnt(&memcg->res);
4955 else if (type == _MEMSWAP)
4956 res_counter_reset_failcnt(&memcg->memsw);
4957 else if (type == _KMEM)
4958 res_counter_reset_failcnt(&memcg->kmem);
4967 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
4970 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
4974 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4975 struct cftype *cft, u64 val)
4977 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4979 if (val >= (1 << NR_MOVE_TYPE))
4983 * No kind of locking is needed in here, because ->can_attach() will
4984 * check this value once in the beginning of the process, and then carry
4985 * on with stale data. This means that changes to this value will only
4986 * affect task migrations starting after the change.
4988 memcg->move_charge_at_immigrate = val;
4992 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4993 struct cftype *cft, u64 val)
5000 static int memcg_numa_stat_show(struct cgroup_subsys_state *css,
5001 struct cftype *cft, struct seq_file *m)
5004 unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
5005 unsigned long node_nr;
5006 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5008 total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL);
5009 seq_printf(m, "total=%lu", total_nr);
5010 for_each_node_state(nid, N_MEMORY) {
5011 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL);
5012 seq_printf(m, " N%d=%lu", nid, node_nr);
5016 file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE);
5017 seq_printf(m, "file=%lu", file_nr);
5018 for_each_node_state(nid, N_MEMORY) {
5019 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5021 seq_printf(m, " N%d=%lu", nid, node_nr);
5025 anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON);
5026 seq_printf(m, "anon=%lu", anon_nr);
5027 for_each_node_state(nid, N_MEMORY) {
5028 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5030 seq_printf(m, " N%d=%lu", nid, node_nr);
5034 unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
5035 seq_printf(m, "unevictable=%lu", unevictable_nr);
5036 for_each_node_state(nid, N_MEMORY) {
5037 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5038 BIT(LRU_UNEVICTABLE));
5039 seq_printf(m, " N%d=%lu", nid, node_nr);
5044 #endif /* CONFIG_NUMA */
5046 static inline void mem_cgroup_lru_names_not_uptodate(void)
5048 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5051 static int memcg_stat_show(struct cgroup_subsys_state *css, struct cftype *cft,
5054 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5055 struct mem_cgroup *mi;
5058 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5059 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5061 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5062 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
5065 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5066 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5067 mem_cgroup_read_events(memcg, i));
5069 for (i = 0; i < NR_LRU_LISTS; i++)
5070 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5071 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5073 /* Hierarchical information */
5075 unsigned long long limit, memsw_limit;
5076 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
5077 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
5078 if (do_swap_account)
5079 seq_printf(m, "hierarchical_memsw_limit %llu\n",
5083 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5086 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5088 for_each_mem_cgroup_tree(mi, memcg)
5089 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5090 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5093 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5094 unsigned long long val = 0;
5096 for_each_mem_cgroup_tree(mi, memcg)
5097 val += mem_cgroup_read_events(mi, i);
5098 seq_printf(m, "total_%s %llu\n",
5099 mem_cgroup_events_names[i], val);
5102 for (i = 0; i < NR_LRU_LISTS; i++) {
5103 unsigned long long val = 0;
5105 for_each_mem_cgroup_tree(mi, memcg)
5106 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5107 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
5110 #ifdef CONFIG_DEBUG_VM
5113 struct mem_cgroup_per_zone *mz;
5114 struct zone_reclaim_stat *rstat;
5115 unsigned long recent_rotated[2] = {0, 0};
5116 unsigned long recent_scanned[2] = {0, 0};
5118 for_each_online_node(nid)
5119 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
5120 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
5121 rstat = &mz->lruvec.reclaim_stat;
5123 recent_rotated[0] += rstat->recent_rotated[0];
5124 recent_rotated[1] += rstat->recent_rotated[1];
5125 recent_scanned[0] += rstat->recent_scanned[0];
5126 recent_scanned[1] += rstat->recent_scanned[1];
5128 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5129 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5130 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5131 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
5138 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
5141 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5143 return mem_cgroup_swappiness(memcg);
5146 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
5147 struct cftype *cft, u64 val)
5149 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5150 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5152 if (val > 100 || !parent)
5155 mutex_lock(&memcg_create_mutex);
5157 /* If under hierarchy, only empty-root can set this value */
5158 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5159 mutex_unlock(&memcg_create_mutex);
5163 memcg->swappiness = val;
5165 mutex_unlock(&memcg_create_mutex);
5170 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5172 struct mem_cgroup_threshold_ary *t;
5178 t = rcu_dereference(memcg->thresholds.primary);
5180 t = rcu_dereference(memcg->memsw_thresholds.primary);
5185 usage = mem_cgroup_usage(memcg, swap);
5188 * current_threshold points to threshold just below or equal to usage.
5189 * If it's not true, a threshold was crossed after last
5190 * call of __mem_cgroup_threshold().
5192 i = t->current_threshold;
5195 * Iterate backward over array of thresholds starting from
5196 * current_threshold and check if a threshold is crossed.
5197 * If none of thresholds below usage is crossed, we read
5198 * only one element of the array here.
5200 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5201 eventfd_signal(t->entries[i].eventfd, 1);
5203 /* i = current_threshold + 1 */
5207 * Iterate forward over array of thresholds starting from
5208 * current_threshold+1 and check if a threshold is crossed.
5209 * If none of thresholds above usage is crossed, we read
5210 * only one element of the array here.
5212 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5213 eventfd_signal(t->entries[i].eventfd, 1);
5215 /* Update current_threshold */
5216 t->current_threshold = i - 1;
5221 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5224 __mem_cgroup_threshold(memcg, false);
5225 if (do_swap_account)
5226 __mem_cgroup_threshold(memcg, true);
5228 memcg = parent_mem_cgroup(memcg);
5232 static int compare_thresholds(const void *a, const void *b)
5234 const struct mem_cgroup_threshold *_a = a;
5235 const struct mem_cgroup_threshold *_b = b;
5237 if (_a->threshold > _b->threshold)
5240 if (_a->threshold < _b->threshold)
5246 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
5248 struct mem_cgroup_eventfd_list *ev;
5250 list_for_each_entry(ev, &memcg->oom_notify, list)
5251 eventfd_signal(ev->eventfd, 1);
5255 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
5257 struct mem_cgroup *iter;
5259 for_each_mem_cgroup_tree(iter, memcg)
5260 mem_cgroup_oom_notify_cb(iter);
5263 static int mem_cgroup_usage_register_event(struct cgroup_subsys_state *css,
5264 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5266 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5267 struct mem_cgroup_thresholds *thresholds;
5268 struct mem_cgroup_threshold_ary *new;
5269 enum res_type type = MEMFILE_TYPE(cft->private);
5270 u64 threshold, usage;
5273 ret = res_counter_memparse_write_strategy(args, &threshold);
5277 mutex_lock(&memcg->thresholds_lock);
5280 thresholds = &memcg->thresholds;
5281 else if (type == _MEMSWAP)
5282 thresholds = &memcg->memsw_thresholds;
5286 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5288 /* Check if a threshold crossed before adding a new one */
5289 if (thresholds->primary)
5290 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5292 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
5294 /* Allocate memory for new array of thresholds */
5295 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
5303 /* Copy thresholds (if any) to new array */
5304 if (thresholds->primary) {
5305 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
5306 sizeof(struct mem_cgroup_threshold));
5309 /* Add new threshold */
5310 new->entries[size - 1].eventfd = eventfd;
5311 new->entries[size - 1].threshold = threshold;
5313 /* Sort thresholds. Registering of new threshold isn't time-critical */
5314 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
5315 compare_thresholds, NULL);
5317 /* Find current threshold */
5318 new->current_threshold = -1;
5319 for (i = 0; i < size; i++) {
5320 if (new->entries[i].threshold <= usage) {
5322 * new->current_threshold will not be used until
5323 * rcu_assign_pointer(), so it's safe to increment
5326 ++new->current_threshold;
5331 /* Free old spare buffer and save old primary buffer as spare */
5332 kfree(thresholds->spare);
5333 thresholds->spare = thresholds->primary;
5335 rcu_assign_pointer(thresholds->primary, new);
5337 /* To be sure that nobody uses thresholds */
5341 mutex_unlock(&memcg->thresholds_lock);
5346 static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state *css,
5347 struct cftype *cft, struct eventfd_ctx *eventfd)
5349 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5350 struct mem_cgroup_thresholds *thresholds;
5351 struct mem_cgroup_threshold_ary *new;
5352 enum res_type type = MEMFILE_TYPE(cft->private);
5356 mutex_lock(&memcg->thresholds_lock);
5358 thresholds = &memcg->thresholds;
5359 else if (type == _MEMSWAP)
5360 thresholds = &memcg->memsw_thresholds;
5364 if (!thresholds->primary)
5367 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5369 /* Check if a threshold crossed before removing */
5370 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5372 /* Calculate new number of threshold */
5374 for (i = 0; i < thresholds->primary->size; i++) {
5375 if (thresholds->primary->entries[i].eventfd != eventfd)
5379 new = thresholds->spare;
5381 /* Set thresholds array to NULL if we don't have thresholds */
5390 /* Copy thresholds and find current threshold */
5391 new->current_threshold = -1;
5392 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5393 if (thresholds->primary->entries[i].eventfd == eventfd)
5396 new->entries[j] = thresholds->primary->entries[i];
5397 if (new->entries[j].threshold <= usage) {
5399 * new->current_threshold will not be used
5400 * until rcu_assign_pointer(), so it's safe to increment
5403 ++new->current_threshold;
5409 /* Swap primary and spare array */
5410 thresholds->spare = thresholds->primary;
5411 /* If all events are unregistered, free the spare array */
5413 kfree(thresholds->spare);
5414 thresholds->spare = NULL;
5417 rcu_assign_pointer(thresholds->primary, new);
5419 /* To be sure that nobody uses thresholds */
5422 mutex_unlock(&memcg->thresholds_lock);
5425 static int mem_cgroup_oom_register_event(struct cgroup_subsys_state *css,
5426 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5428 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5429 struct mem_cgroup_eventfd_list *event;
5430 enum res_type type = MEMFILE_TYPE(cft->private);
5432 BUG_ON(type != _OOM_TYPE);
5433 event = kmalloc(sizeof(*event), GFP_KERNEL);
5437 spin_lock(&memcg_oom_lock);
5439 event->eventfd = eventfd;
5440 list_add(&event->list, &memcg->oom_notify);
5442 /* already in OOM ? */
5443 if (atomic_read(&memcg->under_oom))
5444 eventfd_signal(eventfd, 1);
5445 spin_unlock(&memcg_oom_lock);
5450 static void mem_cgroup_oom_unregister_event(struct cgroup_subsys_state *css,
5451 struct cftype *cft, struct eventfd_ctx *eventfd)
5453 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5454 struct mem_cgroup_eventfd_list *ev, *tmp;
5455 enum res_type type = MEMFILE_TYPE(cft->private);
5457 BUG_ON(type != _OOM_TYPE);
5459 spin_lock(&memcg_oom_lock);
5461 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
5462 if (ev->eventfd == eventfd) {
5463 list_del(&ev->list);
5468 spin_unlock(&memcg_oom_lock);
5471 static int mem_cgroup_oom_control_read(struct cgroup_subsys_state *css,
5472 struct cftype *cft, struct cgroup_map_cb *cb)
5474 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5476 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
5478 if (atomic_read(&memcg->under_oom))
5479 cb->fill(cb, "under_oom", 1);
5481 cb->fill(cb, "under_oom", 0);
5485 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
5486 struct cftype *cft, u64 val)
5488 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5489 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(&memcg->css));
5491 /* cannot set to root cgroup and only 0 and 1 are allowed */
5492 if (!parent || !((val == 0) || (val == 1)))
5495 mutex_lock(&memcg_create_mutex);
5496 /* oom-kill-disable is a flag for subhierarchy. */
5497 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5498 mutex_unlock(&memcg_create_mutex);
5501 memcg->oom_kill_disable = val;
5503 memcg_oom_recover(memcg);
5504 mutex_unlock(&memcg_create_mutex);
5508 #ifdef CONFIG_MEMCG_KMEM
5509 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5513 memcg->kmemcg_id = -1;
5514 ret = memcg_propagate_kmem(memcg);
5518 return mem_cgroup_sockets_init(memcg, ss);
5521 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5523 mem_cgroup_sockets_destroy(memcg);
5526 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5528 if (!memcg_kmem_is_active(memcg))
5532 * kmem charges can outlive the cgroup. In the case of slab
5533 * pages, for instance, a page contain objects from various
5534 * processes. As we prevent from taking a reference for every
5535 * such allocation we have to be careful when doing uncharge
5536 * (see memcg_uncharge_kmem) and here during offlining.
5538 * The idea is that that only the _last_ uncharge which sees
5539 * the dead memcg will drop the last reference. An additional
5540 * reference is taken here before the group is marked dead
5541 * which is then paired with css_put during uncharge resp. here.
5543 * Although this might sound strange as this path is called from
5544 * css_offline() when the referencemight have dropped down to 0
5545 * and shouldn't be incremented anymore (css_tryget would fail)
5546 * we do not have other options because of the kmem allocations
5549 css_get(&memcg->css);
5551 memcg_kmem_mark_dead(memcg);
5553 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5556 if (memcg_kmem_test_and_clear_dead(memcg))
5557 css_put(&memcg->css);
5560 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5565 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5569 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5574 static struct cftype mem_cgroup_files[] = {
5576 .name = "usage_in_bytes",
5577 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5578 .read = mem_cgroup_read,
5579 .register_event = mem_cgroup_usage_register_event,
5580 .unregister_event = mem_cgroup_usage_unregister_event,
5583 .name = "max_usage_in_bytes",
5584 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5585 .trigger = mem_cgroup_reset,
5586 .read = mem_cgroup_read,
5589 .name = "limit_in_bytes",
5590 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5591 .write_string = mem_cgroup_write,
5592 .read = mem_cgroup_read,
5595 .name = "soft_limit_in_bytes",
5596 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5597 .write_string = mem_cgroup_write,
5598 .read = mem_cgroup_read,
5602 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5603 .trigger = mem_cgroup_reset,
5604 .read = mem_cgroup_read,
5608 .read_seq_string = memcg_stat_show,
5611 .name = "force_empty",
5612 .trigger = mem_cgroup_force_empty_write,
5615 .name = "use_hierarchy",
5616 .flags = CFTYPE_INSANE,
5617 .write_u64 = mem_cgroup_hierarchy_write,
5618 .read_u64 = mem_cgroup_hierarchy_read,
5621 .name = "swappiness",
5622 .read_u64 = mem_cgroup_swappiness_read,
5623 .write_u64 = mem_cgroup_swappiness_write,
5626 .name = "move_charge_at_immigrate",
5627 .read_u64 = mem_cgroup_move_charge_read,
5628 .write_u64 = mem_cgroup_move_charge_write,
5631 .name = "oom_control",
5632 .read_map = mem_cgroup_oom_control_read,
5633 .write_u64 = mem_cgroup_oom_control_write,
5634 .register_event = mem_cgroup_oom_register_event,
5635 .unregister_event = mem_cgroup_oom_unregister_event,
5636 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
5639 .name = "pressure_level",
5640 .register_event = vmpressure_register_event,
5641 .unregister_event = vmpressure_unregister_event,
5645 .name = "numa_stat",
5646 .read_seq_string = memcg_numa_stat_show,
5649 #ifdef CONFIG_MEMCG_KMEM
5651 .name = "kmem.limit_in_bytes",
5652 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5653 .write_string = mem_cgroup_write,
5654 .read = mem_cgroup_read,
5657 .name = "kmem.usage_in_bytes",
5658 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5659 .read = mem_cgroup_read,
5662 .name = "kmem.failcnt",
5663 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5664 .trigger = mem_cgroup_reset,
5665 .read = mem_cgroup_read,
5668 .name = "kmem.max_usage_in_bytes",
5669 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5670 .trigger = mem_cgroup_reset,
5671 .read = mem_cgroup_read,
5673 #ifdef CONFIG_SLABINFO
5675 .name = "kmem.slabinfo",
5676 .read_seq_string = mem_cgroup_slabinfo_read,
5680 { }, /* terminate */
5683 #ifdef CONFIG_MEMCG_SWAP
5684 static struct cftype memsw_cgroup_files[] = {
5686 .name = "memsw.usage_in_bytes",
5687 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
5688 .read = mem_cgroup_read,
5689 .register_event = mem_cgroup_usage_register_event,
5690 .unregister_event = mem_cgroup_usage_unregister_event,
5693 .name = "memsw.max_usage_in_bytes",
5694 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
5695 .trigger = mem_cgroup_reset,
5696 .read = mem_cgroup_read,
5699 .name = "memsw.limit_in_bytes",
5700 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
5701 .write_string = mem_cgroup_write,
5702 .read = mem_cgroup_read,
5705 .name = "memsw.failcnt",
5706 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
5707 .trigger = mem_cgroup_reset,
5708 .read = mem_cgroup_read,
5710 { }, /* terminate */
5713 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5715 struct mem_cgroup_per_node *pn;
5716 struct mem_cgroup_per_zone *mz;
5717 int zone, tmp = node;
5719 * This routine is called against possible nodes.
5720 * But it's BUG to call kmalloc() against offline node.
5722 * TODO: this routine can waste much memory for nodes which will
5723 * never be onlined. It's better to use memory hotplug callback
5726 if (!node_state(node, N_NORMAL_MEMORY))
5728 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5732 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
5733 mz = &pn->zoneinfo[zone];
5734 lruvec_init(&mz->lruvec);
5737 memcg->nodeinfo[node] = pn;
5741 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5743 kfree(memcg->nodeinfo[node]);
5746 static struct mem_cgroup *mem_cgroup_alloc(void)
5748 struct mem_cgroup *memcg;
5749 size_t size = memcg_size();
5751 /* Can be very big if nr_node_ids is very big */
5752 if (size < PAGE_SIZE)
5753 memcg = kzalloc(size, GFP_KERNEL);
5755 memcg = vzalloc(size);
5760 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
5763 spin_lock_init(&memcg->pcp_counter_lock);
5767 if (size < PAGE_SIZE)
5775 * At destroying mem_cgroup, references from swap_cgroup can remain.
5776 * (scanning all at force_empty is too costly...)
5778 * Instead of clearing all references at force_empty, we remember
5779 * the number of reference from swap_cgroup and free mem_cgroup when
5780 * it goes down to 0.
5782 * Removal of cgroup itself succeeds regardless of refs from swap.
5785 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5788 size_t size = memcg_size();
5790 free_css_id(&mem_cgroup_subsys, &memcg->css);
5793 free_mem_cgroup_per_zone_info(memcg, node);
5795 free_percpu(memcg->stat);
5798 * We need to make sure that (at least for now), the jump label
5799 * destruction code runs outside of the cgroup lock. This is because
5800 * get_online_cpus(), which is called from the static_branch update,
5801 * can't be called inside the cgroup_lock. cpusets are the ones
5802 * enforcing this dependency, so if they ever change, we might as well.
5804 * schedule_work() will guarantee this happens. Be careful if you need
5805 * to move this code around, and make sure it is outside
5808 disarm_static_keys(memcg);
5809 if (size < PAGE_SIZE)
5816 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
5818 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
5820 if (!memcg->res.parent)
5822 return mem_cgroup_from_res_counter(memcg->res.parent, res);
5824 EXPORT_SYMBOL(parent_mem_cgroup);
5826 static struct cgroup_subsys_state * __ref
5827 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5829 struct mem_cgroup *memcg;
5830 long error = -ENOMEM;
5833 memcg = mem_cgroup_alloc();
5835 return ERR_PTR(error);
5838 if (alloc_mem_cgroup_per_zone_info(memcg, node))
5842 if (parent_css == NULL) {
5843 root_mem_cgroup = memcg;
5844 res_counter_init(&memcg->res, NULL);
5845 res_counter_init(&memcg->memsw, NULL);
5846 res_counter_init(&memcg->kmem, NULL);
5849 memcg->last_scanned_node = MAX_NUMNODES;
5850 INIT_LIST_HEAD(&memcg->oom_notify);
5851 memcg->move_charge_at_immigrate = 0;
5852 mutex_init(&memcg->thresholds_lock);
5853 spin_lock_init(&memcg->move_lock);
5854 vmpressure_init(&memcg->vmpressure);
5859 __mem_cgroup_free(memcg);
5860 return ERR_PTR(error);
5864 mem_cgroup_css_online(struct cgroup_subsys_state *css)
5866 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5867 struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css));
5873 mutex_lock(&memcg_create_mutex);
5875 memcg->use_hierarchy = parent->use_hierarchy;
5876 memcg->oom_kill_disable = parent->oom_kill_disable;
5877 memcg->swappiness = mem_cgroup_swappiness(parent);
5879 if (parent->use_hierarchy) {
5880 res_counter_init(&memcg->res, &parent->res);
5881 res_counter_init(&memcg->memsw, &parent->memsw);
5882 res_counter_init(&memcg->kmem, &parent->kmem);
5885 * No need to take a reference to the parent because cgroup
5886 * core guarantees its existence.
5889 res_counter_init(&memcg->res, NULL);
5890 res_counter_init(&memcg->memsw, NULL);
5891 res_counter_init(&memcg->kmem, NULL);
5893 * Deeper hierachy with use_hierarchy == false doesn't make
5894 * much sense so let cgroup subsystem know about this
5895 * unfortunate state in our controller.
5897 if (parent != root_mem_cgroup)
5898 mem_cgroup_subsys.broken_hierarchy = true;
5901 error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
5902 mutex_unlock(&memcg_create_mutex);
5907 * Announce all parents that a group from their hierarchy is gone.
5909 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
5911 struct mem_cgroup *parent = memcg;
5913 while ((parent = parent_mem_cgroup(parent)))
5914 mem_cgroup_iter_invalidate(parent);
5917 * if the root memcg is not hierarchical we have to check it
5920 if (!root_mem_cgroup->use_hierarchy)
5921 mem_cgroup_iter_invalidate(root_mem_cgroup);
5924 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5926 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5928 kmem_cgroup_css_offline(memcg);
5930 mem_cgroup_invalidate_reclaim_iterators(memcg);
5931 mem_cgroup_reparent_charges(memcg);
5932 mem_cgroup_destroy_all_caches(memcg);
5933 vmpressure_cleanup(&memcg->vmpressure);
5936 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5938 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5940 memcg_destroy_kmem(memcg);
5941 __mem_cgroup_free(memcg);
5945 /* Handlers for move charge at task migration. */
5946 #define PRECHARGE_COUNT_AT_ONCE 256
5947 static int mem_cgroup_do_precharge(unsigned long count)
5950 int batch_count = PRECHARGE_COUNT_AT_ONCE;
5951 struct mem_cgroup *memcg = mc.to;
5953 if (mem_cgroup_is_root(memcg)) {
5954 mc.precharge += count;
5955 /* we don't need css_get for root */
5958 /* try to charge at once */
5960 struct res_counter *dummy;
5962 * "memcg" cannot be under rmdir() because we've already checked
5963 * by cgroup_lock_live_cgroup() that it is not removed and we
5964 * are still under the same cgroup_mutex. So we can postpone
5967 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
5969 if (do_swap_account && res_counter_charge(&memcg->memsw,
5970 PAGE_SIZE * count, &dummy)) {
5971 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
5974 mc.precharge += count;
5978 /* fall back to one by one charge */
5980 if (signal_pending(current)) {
5984 if (!batch_count--) {
5985 batch_count = PRECHARGE_COUNT_AT_ONCE;
5988 ret = __mem_cgroup_try_charge(NULL,
5989 GFP_KERNEL, 1, &memcg, false);
5991 /* mem_cgroup_clear_mc() will do uncharge later */
5999 * get_mctgt_type - get target type of moving charge
6000 * @vma: the vma the pte to be checked belongs
6001 * @addr: the address corresponding to the pte to be checked
6002 * @ptent: the pte to be checked
6003 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6006 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6007 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6008 * move charge. if @target is not NULL, the page is stored in target->page
6009 * with extra refcnt got(Callers should handle it).
6010 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6011 * target for charge migration. if @target is not NULL, the entry is stored
6014 * Called with pte lock held.
6021 enum mc_target_type {
6027 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6028 unsigned long addr, pte_t ptent)
6030 struct page *page = vm_normal_page(vma, addr, ptent);
6032 if (!page || !page_mapped(page))
6034 if (PageAnon(page)) {
6035 /* we don't move shared anon */
6038 } else if (!move_file())
6039 /* we ignore mapcount for file pages */
6041 if (!get_page_unless_zero(page))
6048 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6049 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6051 struct page *page = NULL;
6052 swp_entry_t ent = pte_to_swp_entry(ptent);
6054 if (!move_anon() || non_swap_entry(ent))
6057 * Because lookup_swap_cache() updates some statistics counter,
6058 * we call find_get_page() with swapper_space directly.
6060 page = find_get_page(swap_address_space(ent), ent.val);
6061 if (do_swap_account)
6062 entry->val = ent.val;
6067 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6068 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6074 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6075 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6077 struct page *page = NULL;
6078 struct address_space *mapping;
6081 if (!vma->vm_file) /* anonymous vma */
6086 mapping = vma->vm_file->f_mapping;
6087 if (pte_none(ptent))
6088 pgoff = linear_page_index(vma, addr);
6089 else /* pte_file(ptent) is true */
6090 pgoff = pte_to_pgoff(ptent);
6092 /* page is moved even if it's not RSS of this task(page-faulted). */
6093 page = find_get_page(mapping, pgoff);
6096 /* shmem/tmpfs may report page out on swap: account for that too. */
6097 if (radix_tree_exceptional_entry(page)) {
6098 swp_entry_t swap = radix_to_swp_entry(page);
6099 if (do_swap_account)
6101 page = find_get_page(swap_address_space(swap), swap.val);
6107 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6108 unsigned long addr, pte_t ptent, union mc_target *target)
6110 struct page *page = NULL;
6111 struct page_cgroup *pc;
6112 enum mc_target_type ret = MC_TARGET_NONE;
6113 swp_entry_t ent = { .val = 0 };
6115 if (pte_present(ptent))
6116 page = mc_handle_present_pte(vma, addr, ptent);
6117 else if (is_swap_pte(ptent))
6118 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
6119 else if (pte_none(ptent) || pte_file(ptent))
6120 page = mc_handle_file_pte(vma, addr, ptent, &ent);
6122 if (!page && !ent.val)
6125 pc = lookup_page_cgroup(page);
6127 * Do only loose check w/o page_cgroup lock.
6128 * mem_cgroup_move_account() checks the pc is valid or not under
6131 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6132 ret = MC_TARGET_PAGE;
6134 target->page = page;
6136 if (!ret || !target)
6139 /* There is a swap entry and a page doesn't exist or isn't charged */
6140 if (ent.val && !ret &&
6141 css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
6142 ret = MC_TARGET_SWAP;
6149 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6151 * We don't consider swapping or file mapped pages because THP does not
6152 * support them for now.
6153 * Caller should make sure that pmd_trans_huge(pmd) is true.
6155 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6156 unsigned long addr, pmd_t pmd, union mc_target *target)
6158 struct page *page = NULL;
6159 struct page_cgroup *pc;
6160 enum mc_target_type ret = MC_TARGET_NONE;
6162 page = pmd_page(pmd);
6163 VM_BUG_ON(!page || !PageHead(page));
6166 pc = lookup_page_cgroup(page);
6167 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6168 ret = MC_TARGET_PAGE;
6171 target->page = page;
6177 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6178 unsigned long addr, pmd_t pmd, union mc_target *target)
6180 return MC_TARGET_NONE;
6184 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6185 unsigned long addr, unsigned long end,
6186 struct mm_walk *walk)
6188 struct vm_area_struct *vma = walk->private;
6192 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6193 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6194 mc.precharge += HPAGE_PMD_NR;
6195 spin_unlock(&vma->vm_mm->page_table_lock);
6199 if (pmd_trans_unstable(pmd))
6201 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6202 for (; addr != end; pte++, addr += PAGE_SIZE)
6203 if (get_mctgt_type(vma, addr, *pte, NULL))
6204 mc.precharge++; /* increment precharge temporarily */
6205 pte_unmap_unlock(pte - 1, ptl);
6211 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6213 unsigned long precharge;
6214 struct vm_area_struct *vma;
6216 down_read(&mm->mmap_sem);
6217 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6218 struct mm_walk mem_cgroup_count_precharge_walk = {
6219 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6223 if (is_vm_hugetlb_page(vma))
6225 walk_page_range(vma->vm_start, vma->vm_end,
6226 &mem_cgroup_count_precharge_walk);
6228 up_read(&mm->mmap_sem);
6230 precharge = mc.precharge;
6236 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6238 unsigned long precharge = mem_cgroup_count_precharge(mm);
6240 VM_BUG_ON(mc.moving_task);
6241 mc.moving_task = current;
6242 return mem_cgroup_do_precharge(precharge);
6245 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6246 static void __mem_cgroup_clear_mc(void)
6248 struct mem_cgroup *from = mc.from;
6249 struct mem_cgroup *to = mc.to;
6252 /* we must uncharge all the leftover precharges from mc.to */
6254 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
6258 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6259 * we must uncharge here.
6261 if (mc.moved_charge) {
6262 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6263 mc.moved_charge = 0;
6265 /* we must fixup refcnts and charges */
6266 if (mc.moved_swap) {
6267 /* uncharge swap account from the old cgroup */
6268 if (!mem_cgroup_is_root(mc.from))
6269 res_counter_uncharge(&mc.from->memsw,
6270 PAGE_SIZE * mc.moved_swap);
6272 for (i = 0; i < mc.moved_swap; i++)
6273 css_put(&mc.from->css);
6275 if (!mem_cgroup_is_root(mc.to)) {
6277 * we charged both to->res and to->memsw, so we should
6280 res_counter_uncharge(&mc.to->res,
6281 PAGE_SIZE * mc.moved_swap);
6283 /* we've already done css_get(mc.to) */
6286 memcg_oom_recover(from);
6287 memcg_oom_recover(to);
6288 wake_up_all(&mc.waitq);
6291 static void mem_cgroup_clear_mc(void)
6293 struct mem_cgroup *from = mc.from;
6296 * we must clear moving_task before waking up waiters at the end of
6299 mc.moving_task = NULL;
6300 __mem_cgroup_clear_mc();
6301 spin_lock(&mc.lock);
6304 spin_unlock(&mc.lock);
6305 mem_cgroup_end_move(from);
6308 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6309 struct cgroup_taskset *tset)
6311 struct task_struct *p = cgroup_taskset_first(tset);
6313 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6314 unsigned long move_charge_at_immigrate;
6317 * We are now commited to this value whatever it is. Changes in this
6318 * tunable will only affect upcoming migrations, not the current one.
6319 * So we need to save it, and keep it going.
6321 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6322 if (move_charge_at_immigrate) {
6323 struct mm_struct *mm;
6324 struct mem_cgroup *from = mem_cgroup_from_task(p);
6326 VM_BUG_ON(from == memcg);
6328 mm = get_task_mm(p);
6331 /* We move charges only when we move a owner of the mm */
6332 if (mm->owner == p) {
6335 VM_BUG_ON(mc.precharge);
6336 VM_BUG_ON(mc.moved_charge);
6337 VM_BUG_ON(mc.moved_swap);
6338 mem_cgroup_start_move(from);
6339 spin_lock(&mc.lock);
6342 mc.immigrate_flags = move_charge_at_immigrate;
6343 spin_unlock(&mc.lock);
6344 /* We set mc.moving_task later */
6346 ret = mem_cgroup_precharge_mc(mm);
6348 mem_cgroup_clear_mc();
6355 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6356 struct cgroup_taskset *tset)
6358 mem_cgroup_clear_mc();
6361 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6362 unsigned long addr, unsigned long end,
6363 struct mm_walk *walk)
6366 struct vm_area_struct *vma = walk->private;
6369 enum mc_target_type target_type;
6370 union mc_target target;
6372 struct page_cgroup *pc;
6375 * We don't take compound_lock() here but no race with splitting thp
6377 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6378 * under splitting, which means there's no concurrent thp split,
6379 * - if another thread runs into split_huge_page() just after we
6380 * entered this if-block, the thread must wait for page table lock
6381 * to be unlocked in __split_huge_page_splitting(), where the main
6382 * part of thp split is not executed yet.
6384 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6385 if (mc.precharge < HPAGE_PMD_NR) {
6386 spin_unlock(&vma->vm_mm->page_table_lock);
6389 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6390 if (target_type == MC_TARGET_PAGE) {
6392 if (!isolate_lru_page(page)) {
6393 pc = lookup_page_cgroup(page);
6394 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6395 pc, mc.from, mc.to)) {
6396 mc.precharge -= HPAGE_PMD_NR;
6397 mc.moved_charge += HPAGE_PMD_NR;
6399 putback_lru_page(page);
6403 spin_unlock(&vma->vm_mm->page_table_lock);
6407 if (pmd_trans_unstable(pmd))
6410 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6411 for (; addr != end; addr += PAGE_SIZE) {
6412 pte_t ptent = *(pte++);
6418 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6419 case MC_TARGET_PAGE:
6421 if (isolate_lru_page(page))
6423 pc = lookup_page_cgroup(page);
6424 if (!mem_cgroup_move_account(page, 1, pc,
6427 /* we uncharge from mc.from later. */
6430 putback_lru_page(page);
6431 put: /* get_mctgt_type() gets the page */
6434 case MC_TARGET_SWAP:
6436 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6438 /* we fixup refcnts and charges later. */
6446 pte_unmap_unlock(pte - 1, ptl);
6451 * We have consumed all precharges we got in can_attach().
6452 * We try charge one by one, but don't do any additional
6453 * charges to mc.to if we have failed in charge once in attach()
6456 ret = mem_cgroup_do_precharge(1);
6464 static void mem_cgroup_move_charge(struct mm_struct *mm)
6466 struct vm_area_struct *vma;
6468 lru_add_drain_all();
6470 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6472 * Someone who are holding the mmap_sem might be waiting in
6473 * waitq. So we cancel all extra charges, wake up all waiters,
6474 * and retry. Because we cancel precharges, we might not be able
6475 * to move enough charges, but moving charge is a best-effort
6476 * feature anyway, so it wouldn't be a big problem.
6478 __mem_cgroup_clear_mc();
6482 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6484 struct mm_walk mem_cgroup_move_charge_walk = {
6485 .pmd_entry = mem_cgroup_move_charge_pte_range,
6489 if (is_vm_hugetlb_page(vma))
6491 ret = walk_page_range(vma->vm_start, vma->vm_end,
6492 &mem_cgroup_move_charge_walk);
6495 * means we have consumed all precharges and failed in
6496 * doing additional charge. Just abandon here.
6500 up_read(&mm->mmap_sem);
6503 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6504 struct cgroup_taskset *tset)
6506 struct task_struct *p = cgroup_taskset_first(tset);
6507 struct mm_struct *mm = get_task_mm(p);
6511 mem_cgroup_move_charge(mm);
6515 mem_cgroup_clear_mc();
6517 #else /* !CONFIG_MMU */
6518 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6519 struct cgroup_taskset *tset)
6523 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6524 struct cgroup_taskset *tset)
6527 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6528 struct cgroup_taskset *tset)
6534 * Cgroup retains root cgroups across [un]mount cycles making it necessary
6535 * to verify sane_behavior flag on each mount attempt.
6537 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
6540 * use_hierarchy is forced with sane_behavior. cgroup core
6541 * guarantees that @root doesn't have any children, so turning it
6542 * on for the root memcg is enough.
6544 if (cgroup_sane_behavior(root_css->cgroup))
6545 mem_cgroup_from_css(root_css)->use_hierarchy = true;
6548 struct cgroup_subsys mem_cgroup_subsys = {
6550 .subsys_id = mem_cgroup_subsys_id,
6551 .css_alloc = mem_cgroup_css_alloc,
6552 .css_online = mem_cgroup_css_online,
6553 .css_offline = mem_cgroup_css_offline,
6554 .css_free = mem_cgroup_css_free,
6555 .can_attach = mem_cgroup_can_attach,
6556 .cancel_attach = mem_cgroup_cancel_attach,
6557 .attach = mem_cgroup_move_task,
6558 .bind = mem_cgroup_bind,
6559 .base_cftypes = mem_cgroup_files,
6564 #ifdef CONFIG_MEMCG_SWAP
6565 static int __init enable_swap_account(char *s)
6567 if (!strcmp(s, "1"))
6568 really_do_swap_account = 1;
6569 else if (!strcmp(s, "0"))
6570 really_do_swap_account = 0;
6573 __setup("swapaccount=", enable_swap_account);
6575 static void __init memsw_file_init(void)
6577 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files));
6580 static void __init enable_swap_cgroup(void)
6582 if (!mem_cgroup_disabled() && really_do_swap_account) {
6583 do_swap_account = 1;
6589 static void __init enable_swap_cgroup(void)
6595 * subsys_initcall() for memory controller.
6597 * Some parts like hotcpu_notifier() have to be initialized from this context
6598 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6599 * everything that doesn't depend on a specific mem_cgroup structure should
6600 * be initialized from here.
6602 static int __init mem_cgroup_init(void)
6604 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6605 enable_swap_cgroup();
6609 subsys_initcall(mem_cgroup_init);