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/page_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/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/page_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
62 #include <net/tcp_memcontrol.h>
65 #include <asm/uaccess.h>
67 #include <trace/events/vmscan.h>
69 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
70 EXPORT_SYMBOL(memory_cgrp_subsys);
72 #define MEM_CGROUP_RECLAIM_RETRIES 5
73 static struct mem_cgroup *root_mem_cgroup __read_mostly;
75 #ifdef CONFIG_MEMCG_SWAP
76 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
77 int do_swap_account __read_mostly;
79 /* for remember boot option*/
80 #ifdef CONFIG_MEMCG_SWAP_ENABLED
81 static int really_do_swap_account __initdata = 1;
83 static int really_do_swap_account __initdata;
87 #define do_swap_account 0
91 static const char * const mem_cgroup_stat_names[] = {
100 enum mem_cgroup_events_index {
101 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
102 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
103 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
104 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
105 MEM_CGROUP_EVENTS_NSTATS,
108 static const char * const mem_cgroup_events_names[] = {
115 static const char * const mem_cgroup_lru_names[] = {
124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
125 * it will be incremated by the number of pages. This counter is used for
126 * for trigger some periodic events. This is straightforward and better
127 * than using jiffies etc. to handle periodic memcg event.
129 enum mem_cgroup_events_target {
130 MEM_CGROUP_TARGET_THRESH,
131 MEM_CGROUP_TARGET_SOFTLIMIT,
132 MEM_CGROUP_TARGET_NUMAINFO,
135 #define THRESHOLDS_EVENTS_TARGET 128
136 #define SOFTLIMIT_EVENTS_TARGET 1024
137 #define NUMAINFO_EVENTS_TARGET 1024
139 struct mem_cgroup_stat_cpu {
140 long count[MEM_CGROUP_STAT_NSTATS];
141 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
142 unsigned long nr_page_events;
143 unsigned long targets[MEM_CGROUP_NTARGETS];
146 struct reclaim_iter {
147 struct mem_cgroup *position;
148 /* scan generation, increased every round-trip */
149 unsigned int generation;
153 * per-zone information in memory controller.
155 struct mem_cgroup_per_zone {
156 struct lruvec lruvec;
157 unsigned long lru_size[NR_LRU_LISTS];
159 struct reclaim_iter iter[DEF_PRIORITY + 1];
161 struct rb_node tree_node; /* RB tree node */
162 unsigned long usage_in_excess;/* Set to the value by which */
163 /* the soft limit is exceeded*/
165 struct mem_cgroup *memcg; /* Back pointer, we cannot */
166 /* use container_of */
169 struct mem_cgroup_per_node {
170 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
174 * Cgroups above their limits are maintained in a RB-Tree, independent of
175 * their hierarchy representation
178 struct mem_cgroup_tree_per_zone {
179 struct rb_root rb_root;
183 struct mem_cgroup_tree_per_node {
184 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
187 struct mem_cgroup_tree {
188 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
191 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
193 struct mem_cgroup_threshold {
194 struct eventfd_ctx *eventfd;
195 unsigned long threshold;
199 struct mem_cgroup_threshold_ary {
200 /* An array index points to threshold just below or equal to usage. */
201 int current_threshold;
202 /* Size of entries[] */
204 /* Array of thresholds */
205 struct mem_cgroup_threshold entries[0];
208 struct mem_cgroup_thresholds {
209 /* Primary thresholds array */
210 struct mem_cgroup_threshold_ary *primary;
212 * Spare threshold array.
213 * This is needed to make mem_cgroup_unregister_event() "never fail".
214 * It must be able to store at least primary->size - 1 entries.
216 struct mem_cgroup_threshold_ary *spare;
220 struct mem_cgroup_eventfd_list {
221 struct list_head list;
222 struct eventfd_ctx *eventfd;
226 * cgroup_event represents events which userspace want to receive.
228 struct mem_cgroup_event {
230 * memcg which the event belongs to.
232 struct mem_cgroup *memcg;
234 * eventfd to signal userspace about the event.
236 struct eventfd_ctx *eventfd;
238 * Each of these stored in a list by the cgroup.
240 struct list_head list;
242 * register_event() callback will be used to add new userspace
243 * waiter for changes related to this event. Use eventfd_signal()
244 * on eventfd to send notification to userspace.
246 int (*register_event)(struct mem_cgroup *memcg,
247 struct eventfd_ctx *eventfd, const char *args);
249 * unregister_event() callback will be called when userspace closes
250 * the eventfd or on cgroup removing. This callback must be set,
251 * if you want provide notification functionality.
253 void (*unregister_event)(struct mem_cgroup *memcg,
254 struct eventfd_ctx *eventfd);
256 * All fields below needed to unregister event when
257 * userspace closes eventfd.
260 wait_queue_head_t *wqh;
262 struct work_struct remove;
265 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
266 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
269 * The memory controller data structure. The memory controller controls both
270 * page cache and RSS per cgroup. We would eventually like to provide
271 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
272 * to help the administrator determine what knobs to tune.
274 * TODO: Add a water mark for the memory controller. Reclaim will begin when
275 * we hit the water mark. May be even add a low water mark, such that
276 * no reclaim occurs from a cgroup at it's low water mark, this is
277 * a feature that will be implemented much later in the future.
280 struct cgroup_subsys_state css;
282 /* Accounted resources */
283 struct page_counter memory;
284 struct page_counter memsw;
285 struct page_counter kmem;
287 unsigned long soft_limit;
289 /* vmpressure notifications */
290 struct vmpressure vmpressure;
292 /* css_online() has been completed */
296 * Should the accounting and control be hierarchical, per subtree?
299 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
303 atomic_t oom_wakeups;
306 /* OOM-Killer disable */
307 int oom_kill_disable;
309 /* protect arrays of thresholds */
310 struct mutex thresholds_lock;
312 /* thresholds for memory usage. RCU-protected */
313 struct mem_cgroup_thresholds thresholds;
315 /* thresholds for mem+swap usage. RCU-protected */
316 struct mem_cgroup_thresholds memsw_thresholds;
318 /* For oom notifier event fd */
319 struct list_head oom_notify;
322 * Should we move charges of a task when a task is moved into this
323 * mem_cgroup ? And what type of charges should we move ?
325 unsigned long move_charge_at_immigrate;
327 * set > 0 if pages under this cgroup are moving to other cgroup.
329 atomic_t moving_account;
330 /* taken only while moving_account > 0 */
331 spinlock_t move_lock;
335 struct mem_cgroup_stat_cpu __percpu *stat;
337 * used when a cpu is offlined or other synchronizations
338 * See mem_cgroup_read_stat().
340 struct mem_cgroup_stat_cpu nocpu_base;
341 spinlock_t pcp_counter_lock;
343 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
344 struct cg_proto tcp_mem;
346 #if defined(CONFIG_MEMCG_KMEM)
347 /* analogous to slab_common's slab_caches list, but per-memcg;
348 * protected by memcg_slab_mutex */
349 struct list_head memcg_slab_caches;
350 /* Index in the kmem_cache->memcg_params->memcg_caches array */
354 int last_scanned_node;
356 nodemask_t scan_nodes;
357 atomic_t numainfo_events;
358 atomic_t numainfo_updating;
361 /* List of events which userspace want to receive */
362 struct list_head event_list;
363 spinlock_t event_list_lock;
365 struct mem_cgroup_per_node *nodeinfo[0];
366 /* WARNING: nodeinfo must be the last member here */
369 /* internal only representation about the status of kmem accounting. */
371 KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */
374 #ifdef CONFIG_MEMCG_KMEM
375 static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
377 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
380 static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
382 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
387 /* Stuffs for move charges at task migration. */
389 * Types of charges to be moved. "move_charge_at_immitgrate" and
390 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
393 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
394 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
398 /* "mc" and its members are protected by cgroup_mutex */
399 static struct move_charge_struct {
400 spinlock_t lock; /* for from, to */
401 struct mem_cgroup *from;
402 struct mem_cgroup *to;
403 unsigned long immigrate_flags;
404 unsigned long precharge;
405 unsigned long moved_charge;
406 unsigned long moved_swap;
407 struct task_struct *moving_task; /* a task moving charges */
408 wait_queue_head_t waitq; /* a waitq for other context */
410 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
411 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
414 static bool move_anon(void)
416 return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
419 static bool move_file(void)
421 return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
425 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
426 * limit reclaim to prevent infinite loops, if they ever occur.
428 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
429 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
432 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
433 MEM_CGROUP_CHARGE_TYPE_ANON,
434 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
435 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
439 /* for encoding cft->private value on file */
447 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
448 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
449 #define MEMFILE_ATTR(val) ((val) & 0xffff)
450 /* Used for OOM nofiier */
451 #define OOM_CONTROL (0)
454 * The memcg_create_mutex will be held whenever a new cgroup is created.
455 * As a consequence, any change that needs to protect against new child cgroups
456 * appearing has to hold it as well.
458 static DEFINE_MUTEX(memcg_create_mutex);
460 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
462 return s ? container_of(s, struct mem_cgroup, css) : NULL;
465 /* Some nice accessors for the vmpressure. */
466 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
469 memcg = root_mem_cgroup;
470 return &memcg->vmpressure;
473 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
475 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
478 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
480 return (memcg == root_mem_cgroup);
484 * We restrict the id in the range of [1, 65535], so it can fit into
487 #define MEM_CGROUP_ID_MAX USHRT_MAX
489 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
491 return memcg->css.id;
494 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
496 struct cgroup_subsys_state *css;
498 css = css_from_id(id, &memory_cgrp_subsys);
499 return mem_cgroup_from_css(css);
502 /* Writing them here to avoid exposing memcg's inner layout */
503 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
505 void sock_update_memcg(struct sock *sk)
507 if (mem_cgroup_sockets_enabled) {
508 struct mem_cgroup *memcg;
509 struct cg_proto *cg_proto;
511 BUG_ON(!sk->sk_prot->proto_cgroup);
513 /* Socket cloning can throw us here with sk_cgrp already
514 * filled. It won't however, necessarily happen from
515 * process context. So the test for root memcg given
516 * the current task's memcg won't help us in this case.
518 * Respecting the original socket's memcg is a better
519 * decision in this case.
522 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
523 css_get(&sk->sk_cgrp->memcg->css);
528 memcg = mem_cgroup_from_task(current);
529 cg_proto = sk->sk_prot->proto_cgroup(memcg);
530 if (!mem_cgroup_is_root(memcg) &&
531 memcg_proto_active(cg_proto) &&
532 css_tryget_online(&memcg->css)) {
533 sk->sk_cgrp = cg_proto;
538 EXPORT_SYMBOL(sock_update_memcg);
540 void sock_release_memcg(struct sock *sk)
542 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
543 struct mem_cgroup *memcg;
544 WARN_ON(!sk->sk_cgrp->memcg);
545 memcg = sk->sk_cgrp->memcg;
546 css_put(&sk->sk_cgrp->memcg->css);
550 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
552 if (!memcg || mem_cgroup_is_root(memcg))
555 return &memcg->tcp_mem;
557 EXPORT_SYMBOL(tcp_proto_cgroup);
559 static void disarm_sock_keys(struct mem_cgroup *memcg)
561 if (!memcg_proto_activated(&memcg->tcp_mem))
563 static_key_slow_dec(&memcg_socket_limit_enabled);
566 static void disarm_sock_keys(struct mem_cgroup *memcg)
571 #ifdef CONFIG_MEMCG_KMEM
573 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
574 * The main reason for not using cgroup id for this:
575 * this works better in sparse environments, where we have a lot of memcgs,
576 * but only a few kmem-limited. Or also, if we have, for instance, 200
577 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
578 * 200 entry array for that.
580 * The current size of the caches array is stored in
581 * memcg_limited_groups_array_size. It will double each time we have to
584 static DEFINE_IDA(kmem_limited_groups);
585 int memcg_limited_groups_array_size;
588 * MIN_SIZE is different than 1, because we would like to avoid going through
589 * the alloc/free process all the time. In a small machine, 4 kmem-limited
590 * cgroups is a reasonable guess. In the future, it could be a parameter or
591 * tunable, but that is strictly not necessary.
593 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
594 * this constant directly from cgroup, but it is understandable that this is
595 * better kept as an internal representation in cgroup.c. In any case, the
596 * cgrp_id space is not getting any smaller, and we don't have to necessarily
597 * increase ours as well if it increases.
599 #define MEMCG_CACHES_MIN_SIZE 4
600 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
603 * A lot of the calls to the cache allocation functions are expected to be
604 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
605 * conditional to this static branch, we'll have to allow modules that does
606 * kmem_cache_alloc and the such to see this symbol as well
608 struct static_key memcg_kmem_enabled_key;
609 EXPORT_SYMBOL(memcg_kmem_enabled_key);
611 static void memcg_free_cache_id(int id);
613 static void disarm_kmem_keys(struct mem_cgroup *memcg)
615 if (memcg_kmem_is_active(memcg)) {
616 static_key_slow_dec(&memcg_kmem_enabled_key);
617 memcg_free_cache_id(memcg->kmemcg_id);
620 * This check can't live in kmem destruction function,
621 * since the charges will outlive the cgroup
623 WARN_ON(page_counter_read(&memcg->kmem));
626 static void disarm_kmem_keys(struct mem_cgroup *memcg)
629 #endif /* CONFIG_MEMCG_KMEM */
631 static void disarm_static_keys(struct mem_cgroup *memcg)
633 disarm_sock_keys(memcg);
634 disarm_kmem_keys(memcg);
637 static struct mem_cgroup_per_zone *
638 mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
640 int nid = zone_to_nid(zone);
641 int zid = zone_idx(zone);
643 return &memcg->nodeinfo[nid]->zoneinfo[zid];
646 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
651 static struct mem_cgroup_per_zone *
652 mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
654 int nid = page_to_nid(page);
655 int zid = page_zonenum(page);
657 return &memcg->nodeinfo[nid]->zoneinfo[zid];
660 static struct mem_cgroup_tree_per_zone *
661 soft_limit_tree_node_zone(int nid, int zid)
663 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
666 static struct mem_cgroup_tree_per_zone *
667 soft_limit_tree_from_page(struct page *page)
669 int nid = page_to_nid(page);
670 int zid = page_zonenum(page);
672 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
675 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
676 struct mem_cgroup_tree_per_zone *mctz,
677 unsigned long new_usage_in_excess)
679 struct rb_node **p = &mctz->rb_root.rb_node;
680 struct rb_node *parent = NULL;
681 struct mem_cgroup_per_zone *mz_node;
686 mz->usage_in_excess = new_usage_in_excess;
687 if (!mz->usage_in_excess)
691 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
693 if (mz->usage_in_excess < mz_node->usage_in_excess)
696 * We can't avoid mem cgroups that are over their soft
697 * limit by the same amount
699 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
702 rb_link_node(&mz->tree_node, parent, p);
703 rb_insert_color(&mz->tree_node, &mctz->rb_root);
707 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
708 struct mem_cgroup_tree_per_zone *mctz)
712 rb_erase(&mz->tree_node, &mctz->rb_root);
716 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
717 struct mem_cgroup_tree_per_zone *mctz)
721 spin_lock_irqsave(&mctz->lock, flags);
722 __mem_cgroup_remove_exceeded(mz, mctz);
723 spin_unlock_irqrestore(&mctz->lock, flags);
726 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
728 unsigned long nr_pages = page_counter_read(&memcg->memory);
729 unsigned long soft_limit = ACCESS_ONCE(memcg->soft_limit);
730 unsigned long excess = 0;
732 if (nr_pages > soft_limit)
733 excess = nr_pages - soft_limit;
738 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
740 unsigned long excess;
741 struct mem_cgroup_per_zone *mz;
742 struct mem_cgroup_tree_per_zone *mctz;
744 mctz = soft_limit_tree_from_page(page);
746 * Necessary to update all ancestors when hierarchy is used.
747 * because their event counter is not touched.
749 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
750 mz = mem_cgroup_page_zoneinfo(memcg, page);
751 excess = soft_limit_excess(memcg);
753 * We have to update the tree if mz is on RB-tree or
754 * mem is over its softlimit.
756 if (excess || mz->on_tree) {
759 spin_lock_irqsave(&mctz->lock, flags);
760 /* if on-tree, remove it */
762 __mem_cgroup_remove_exceeded(mz, mctz);
764 * Insert again. mz->usage_in_excess will be updated.
765 * If excess is 0, no tree ops.
767 __mem_cgroup_insert_exceeded(mz, mctz, excess);
768 spin_unlock_irqrestore(&mctz->lock, flags);
773 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
775 struct mem_cgroup_tree_per_zone *mctz;
776 struct mem_cgroup_per_zone *mz;
780 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
781 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
782 mctz = soft_limit_tree_node_zone(nid, zid);
783 mem_cgroup_remove_exceeded(mz, mctz);
788 static struct mem_cgroup_per_zone *
789 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
791 struct rb_node *rightmost = NULL;
792 struct mem_cgroup_per_zone *mz;
796 rightmost = rb_last(&mctz->rb_root);
798 goto done; /* Nothing to reclaim from */
800 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
802 * Remove the node now but someone else can add it back,
803 * we will to add it back at the end of reclaim to its correct
804 * position in the tree.
806 __mem_cgroup_remove_exceeded(mz, mctz);
807 if (!soft_limit_excess(mz->memcg) ||
808 !css_tryget_online(&mz->memcg->css))
814 static struct mem_cgroup_per_zone *
815 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
817 struct mem_cgroup_per_zone *mz;
819 spin_lock_irq(&mctz->lock);
820 mz = __mem_cgroup_largest_soft_limit_node(mctz);
821 spin_unlock_irq(&mctz->lock);
826 * Implementation Note: reading percpu statistics for memcg.
828 * Both of vmstat[] and percpu_counter has threshold and do periodic
829 * synchronization to implement "quick" read. There are trade-off between
830 * reading cost and precision of value. Then, we may have a chance to implement
831 * a periodic synchronizion of counter in memcg's counter.
833 * But this _read() function is used for user interface now. The user accounts
834 * memory usage by memory cgroup and he _always_ requires exact value because
835 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
836 * have to visit all online cpus and make sum. So, for now, unnecessary
837 * synchronization is not implemented. (just implemented for cpu hotplug)
839 * If there are kernel internal actions which can make use of some not-exact
840 * value, and reading all cpu value can be performance bottleneck in some
841 * common workload, threashold and synchonization as vmstat[] should be
844 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
845 enum mem_cgroup_stat_index idx)
851 for_each_online_cpu(cpu)
852 val += per_cpu(memcg->stat->count[idx], cpu);
853 #ifdef CONFIG_HOTPLUG_CPU
854 spin_lock(&memcg->pcp_counter_lock);
855 val += memcg->nocpu_base.count[idx];
856 spin_unlock(&memcg->pcp_counter_lock);
862 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
863 enum mem_cgroup_events_index idx)
865 unsigned long val = 0;
869 for_each_online_cpu(cpu)
870 val += per_cpu(memcg->stat->events[idx], cpu);
871 #ifdef CONFIG_HOTPLUG_CPU
872 spin_lock(&memcg->pcp_counter_lock);
873 val += memcg->nocpu_base.events[idx];
874 spin_unlock(&memcg->pcp_counter_lock);
880 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
885 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
886 * counted as CACHE even if it's on ANON LRU.
889 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
892 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
895 if (PageTransHuge(page))
896 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
899 /* pagein of a big page is an event. So, ignore page size */
901 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
903 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
904 nr_pages = -nr_pages; /* for event */
907 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
910 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
912 struct mem_cgroup_per_zone *mz;
914 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
915 return mz->lru_size[lru];
918 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
920 unsigned int lru_mask)
922 unsigned long nr = 0;
925 VM_BUG_ON((unsigned)nid >= nr_node_ids);
927 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
928 struct mem_cgroup_per_zone *mz;
932 if (!(BIT(lru) & lru_mask))
934 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
935 nr += mz->lru_size[lru];
941 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
942 unsigned int lru_mask)
944 unsigned long nr = 0;
947 for_each_node_state(nid, N_MEMORY)
948 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
952 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
953 enum mem_cgroup_events_target target)
955 unsigned long val, next;
957 val = __this_cpu_read(memcg->stat->nr_page_events);
958 next = __this_cpu_read(memcg->stat->targets[target]);
959 /* from time_after() in jiffies.h */
960 if ((long)next - (long)val < 0) {
962 case MEM_CGROUP_TARGET_THRESH:
963 next = val + THRESHOLDS_EVENTS_TARGET;
965 case MEM_CGROUP_TARGET_SOFTLIMIT:
966 next = val + SOFTLIMIT_EVENTS_TARGET;
968 case MEM_CGROUP_TARGET_NUMAINFO:
969 next = val + NUMAINFO_EVENTS_TARGET;
974 __this_cpu_write(memcg->stat->targets[target], next);
981 * Check events in order.
984 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
986 /* threshold event is triggered in finer grain than soft limit */
987 if (unlikely(mem_cgroup_event_ratelimit(memcg,
988 MEM_CGROUP_TARGET_THRESH))) {
990 bool do_numainfo __maybe_unused;
992 do_softlimit = mem_cgroup_event_ratelimit(memcg,
993 MEM_CGROUP_TARGET_SOFTLIMIT);
995 do_numainfo = mem_cgroup_event_ratelimit(memcg,
996 MEM_CGROUP_TARGET_NUMAINFO);
998 mem_cgroup_threshold(memcg);
999 if (unlikely(do_softlimit))
1000 mem_cgroup_update_tree(memcg, page);
1001 #if MAX_NUMNODES > 1
1002 if (unlikely(do_numainfo))
1003 atomic_inc(&memcg->numainfo_events);
1008 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1011 * mm_update_next_owner() may clear mm->owner to NULL
1012 * if it races with swapoff, page migration, etc.
1013 * So this can be called with p == NULL.
1018 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
1021 static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
1023 struct mem_cgroup *memcg = NULL;
1028 * Page cache insertions can happen withou an
1029 * actual mm context, e.g. during disk probing
1030 * on boot, loopback IO, acct() writes etc.
1033 memcg = root_mem_cgroup;
1035 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1036 if (unlikely(!memcg))
1037 memcg = root_mem_cgroup;
1039 } while (!css_tryget_online(&memcg->css));
1045 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1046 * @root: hierarchy root
1047 * @prev: previously returned memcg, NULL on first invocation
1048 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1050 * Returns references to children of the hierarchy below @root, or
1051 * @root itself, or %NULL after a full round-trip.
1053 * Caller must pass the return value in @prev on subsequent
1054 * invocations for reference counting, or use mem_cgroup_iter_break()
1055 * to cancel a hierarchy walk before the round-trip is complete.
1057 * Reclaimers can specify a zone and a priority level in @reclaim to
1058 * divide up the memcgs in the hierarchy among all concurrent
1059 * reclaimers operating on the same zone and priority.
1061 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1062 struct mem_cgroup *prev,
1063 struct mem_cgroup_reclaim_cookie *reclaim)
1065 struct reclaim_iter *uninitialized_var(iter);
1066 struct cgroup_subsys_state *css = NULL;
1067 struct mem_cgroup *memcg = NULL;
1068 struct mem_cgroup *pos = NULL;
1070 if (mem_cgroup_disabled())
1074 root = root_mem_cgroup;
1076 if (prev && !reclaim)
1079 if (!root->use_hierarchy && root != root_mem_cgroup) {
1088 struct mem_cgroup_per_zone *mz;
1090 mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
1091 iter = &mz->iter[reclaim->priority];
1093 if (prev && reclaim->generation != iter->generation)
1097 pos = ACCESS_ONCE(iter->position);
1099 * A racing update may change the position and
1100 * put the last reference, hence css_tryget(),
1101 * or retry to see the updated position.
1103 } while (pos && !css_tryget(&pos->css));
1110 css = css_next_descendant_pre(css, &root->css);
1113 * Reclaimers share the hierarchy walk, and a
1114 * new one might jump in right at the end of
1115 * the hierarchy - make sure they see at least
1116 * one group and restart from the beginning.
1124 * Verify the css and acquire a reference. The root
1125 * is provided by the caller, so we know it's alive
1126 * and kicking, and don't take an extra reference.
1128 memcg = mem_cgroup_from_css(css);
1130 if (css == &root->css)
1133 if (css_tryget(css)) {
1135 * Make sure the memcg is initialized:
1136 * mem_cgroup_css_online() orders the the
1137 * initialization against setting the flag.
1139 if (smp_load_acquire(&memcg->initialized))
1149 if (cmpxchg(&iter->position, pos, memcg) == pos) {
1151 css_get(&memcg->css);
1157 * pairs with css_tryget when dereferencing iter->position
1166 reclaim->generation = iter->generation;
1172 if (prev && prev != root)
1173 css_put(&prev->css);
1179 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1180 * @root: hierarchy root
1181 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1183 void mem_cgroup_iter_break(struct mem_cgroup *root,
1184 struct mem_cgroup *prev)
1187 root = root_mem_cgroup;
1188 if (prev && prev != root)
1189 css_put(&prev->css);
1193 * Iteration constructs for visiting all cgroups (under a tree). If
1194 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1195 * be used for reference counting.
1197 #define for_each_mem_cgroup_tree(iter, root) \
1198 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1200 iter = mem_cgroup_iter(root, iter, NULL))
1202 #define for_each_mem_cgroup(iter) \
1203 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1205 iter = mem_cgroup_iter(NULL, iter, NULL))
1207 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1209 struct mem_cgroup *memcg;
1212 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1213 if (unlikely(!memcg))
1218 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1221 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1229 EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1232 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1233 * @zone: zone of the wanted lruvec
1234 * @memcg: memcg of the wanted lruvec
1236 * Returns the lru list vector holding pages for the given @zone and
1237 * @mem. This can be the global zone lruvec, if the memory controller
1240 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1241 struct mem_cgroup *memcg)
1243 struct mem_cgroup_per_zone *mz;
1244 struct lruvec *lruvec;
1246 if (mem_cgroup_disabled()) {
1247 lruvec = &zone->lruvec;
1251 mz = mem_cgroup_zone_zoneinfo(memcg, zone);
1252 lruvec = &mz->lruvec;
1255 * Since a node can be onlined after the mem_cgroup was created,
1256 * we have to be prepared to initialize lruvec->zone here;
1257 * and if offlined then reonlined, we need to reinitialize it.
1259 if (unlikely(lruvec->zone != zone))
1260 lruvec->zone = zone;
1265 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1267 * @zone: zone of the page
1269 * This function is only safe when following the LRU page isolation
1270 * and putback protocol: the LRU lock must be held, and the page must
1271 * either be PageLRU() or the caller must have isolated/allocated it.
1273 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1275 struct mem_cgroup_per_zone *mz;
1276 struct mem_cgroup *memcg;
1277 struct lruvec *lruvec;
1279 if (mem_cgroup_disabled()) {
1280 lruvec = &zone->lruvec;
1284 memcg = page->mem_cgroup;
1286 * Swapcache readahead pages are added to the LRU - and
1287 * possibly migrated - before they are charged.
1290 memcg = root_mem_cgroup;
1292 mz = mem_cgroup_page_zoneinfo(memcg, page);
1293 lruvec = &mz->lruvec;
1296 * Since a node can be onlined after the mem_cgroup was created,
1297 * we have to be prepared to initialize lruvec->zone here;
1298 * and if offlined then reonlined, we need to reinitialize it.
1300 if (unlikely(lruvec->zone != zone))
1301 lruvec->zone = zone;
1306 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1307 * @lruvec: mem_cgroup per zone lru vector
1308 * @lru: index of lru list the page is sitting on
1309 * @nr_pages: positive when adding or negative when removing
1311 * This function must be called when a page is added to or removed from an
1314 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1317 struct mem_cgroup_per_zone *mz;
1318 unsigned long *lru_size;
1320 if (mem_cgroup_disabled())
1323 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1324 lru_size = mz->lru_size + lru;
1325 *lru_size += nr_pages;
1326 VM_BUG_ON((long)(*lru_size) < 0);
1329 bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, struct mem_cgroup *root)
1333 if (!root->use_hierarchy)
1335 return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
1338 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
1340 struct mem_cgroup *task_memcg;
1341 struct task_struct *p;
1344 p = find_lock_task_mm(task);
1346 task_memcg = get_mem_cgroup_from_mm(p->mm);
1350 * All threads may have already detached their mm's, but the oom
1351 * killer still needs to detect if they have already been oom
1352 * killed to prevent needlessly killing additional tasks.
1355 task_memcg = mem_cgroup_from_task(task);
1356 css_get(&task_memcg->css);
1359 ret = mem_cgroup_is_descendant(task_memcg, memcg);
1360 css_put(&task_memcg->css);
1364 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1366 unsigned long inactive_ratio;
1367 unsigned long inactive;
1368 unsigned long active;
1371 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1372 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1374 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1376 inactive_ratio = int_sqrt(10 * gb);
1380 return inactive * inactive_ratio < active;
1383 #define mem_cgroup_from_counter(counter, member) \
1384 container_of(counter, struct mem_cgroup, member)
1387 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1388 * @memcg: the memory cgroup
1390 * Returns the maximum amount of memory @mem can be charged with, in
1393 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1395 unsigned long margin = 0;
1396 unsigned long count;
1397 unsigned long limit;
1399 count = page_counter_read(&memcg->memory);
1400 limit = ACCESS_ONCE(memcg->memory.limit);
1402 margin = limit - count;
1404 if (do_swap_account) {
1405 count = page_counter_read(&memcg->memsw);
1406 limit = ACCESS_ONCE(memcg->memsw.limit);
1408 margin = min(margin, limit - count);
1414 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1417 if (mem_cgroup_disabled() || !memcg->css.parent)
1418 return vm_swappiness;
1420 return memcg->swappiness;
1424 * A routine for checking "mem" is under move_account() or not.
1426 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1427 * moving cgroups. This is for waiting at high-memory pressure
1430 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1432 struct mem_cgroup *from;
1433 struct mem_cgroup *to;
1436 * Unlike task_move routines, we access mc.to, mc.from not under
1437 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1439 spin_lock(&mc.lock);
1445 ret = mem_cgroup_is_descendant(from, memcg) ||
1446 mem_cgroup_is_descendant(to, memcg);
1448 spin_unlock(&mc.lock);
1452 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1454 if (mc.moving_task && current != mc.moving_task) {
1455 if (mem_cgroup_under_move(memcg)) {
1457 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1458 /* moving charge context might have finished. */
1461 finish_wait(&mc.waitq, &wait);
1468 #define K(x) ((x) << (PAGE_SHIFT-10))
1470 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1471 * @memcg: The memory cgroup that went over limit
1472 * @p: Task that is going to be killed
1474 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1477 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1479 /* oom_info_lock ensures that parallel ooms do not interleave */
1480 static DEFINE_MUTEX(oom_info_lock);
1481 struct mem_cgroup *iter;
1487 mutex_lock(&oom_info_lock);
1490 pr_info("Task in ");
1491 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1492 pr_info(" killed as a result of limit of ");
1493 pr_cont_cgroup_path(memcg->css.cgroup);
1498 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1499 K((u64)page_counter_read(&memcg->memory)),
1500 K((u64)memcg->memory.limit), memcg->memory.failcnt);
1501 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1502 K((u64)page_counter_read(&memcg->memsw)),
1503 K((u64)memcg->memsw.limit), memcg->memsw.failcnt);
1504 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1505 K((u64)page_counter_read(&memcg->kmem)),
1506 K((u64)memcg->kmem.limit), memcg->kmem.failcnt);
1508 for_each_mem_cgroup_tree(iter, memcg) {
1509 pr_info("Memory cgroup stats for ");
1510 pr_cont_cgroup_path(iter->css.cgroup);
1513 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1514 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1516 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1517 K(mem_cgroup_read_stat(iter, i)));
1520 for (i = 0; i < NR_LRU_LISTS; i++)
1521 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1522 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1526 mutex_unlock(&oom_info_lock);
1530 * This function returns the number of memcg under hierarchy tree. Returns
1531 * 1(self count) if no children.
1533 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1536 struct mem_cgroup *iter;
1538 for_each_mem_cgroup_tree(iter, memcg)
1544 * Return the memory (and swap, if configured) limit for a memcg.
1546 static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
1548 unsigned long limit;
1550 limit = memcg->memory.limit;
1551 if (mem_cgroup_swappiness(memcg)) {
1552 unsigned long memsw_limit;
1554 memsw_limit = memcg->memsw.limit;
1555 limit = min(limit + total_swap_pages, memsw_limit);
1560 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1563 struct mem_cgroup *iter;
1564 unsigned long chosen_points = 0;
1565 unsigned long totalpages;
1566 unsigned int points = 0;
1567 struct task_struct *chosen = NULL;
1570 * If current has a pending SIGKILL or is exiting, then automatically
1571 * select it. The goal is to allow it to allocate so that it may
1572 * quickly exit and free its memory.
1574 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1575 set_thread_flag(TIF_MEMDIE);
1579 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1580 totalpages = mem_cgroup_get_limit(memcg) ? : 1;
1581 for_each_mem_cgroup_tree(iter, memcg) {
1582 struct css_task_iter it;
1583 struct task_struct *task;
1585 css_task_iter_start(&iter->css, &it);
1586 while ((task = css_task_iter_next(&it))) {
1587 switch (oom_scan_process_thread(task, totalpages, NULL,
1589 case OOM_SCAN_SELECT:
1591 put_task_struct(chosen);
1593 chosen_points = ULONG_MAX;
1594 get_task_struct(chosen);
1596 case OOM_SCAN_CONTINUE:
1598 case OOM_SCAN_ABORT:
1599 css_task_iter_end(&it);
1600 mem_cgroup_iter_break(memcg, iter);
1602 put_task_struct(chosen);
1607 points = oom_badness(task, memcg, NULL, totalpages);
1608 if (!points || points < chosen_points)
1610 /* Prefer thread group leaders for display purposes */
1611 if (points == chosen_points &&
1612 thread_group_leader(chosen))
1616 put_task_struct(chosen);
1618 chosen_points = points;
1619 get_task_struct(chosen);
1621 css_task_iter_end(&it);
1626 points = chosen_points * 1000 / totalpages;
1627 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1628 NULL, "Memory cgroup out of memory");
1632 * test_mem_cgroup_node_reclaimable
1633 * @memcg: the target memcg
1634 * @nid: the node ID to be checked.
1635 * @noswap : specify true here if the user wants flle only information.
1637 * This function returns whether the specified memcg contains any
1638 * reclaimable pages on a node. Returns true if there are any reclaimable
1639 * pages in the node.
1641 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1642 int nid, bool noswap)
1644 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1646 if (noswap || !total_swap_pages)
1648 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1653 #if MAX_NUMNODES > 1
1656 * Always updating the nodemask is not very good - even if we have an empty
1657 * list or the wrong list here, we can start from some node and traverse all
1658 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1661 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1665 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1666 * pagein/pageout changes since the last update.
1668 if (!atomic_read(&memcg->numainfo_events))
1670 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1673 /* make a nodemask where this memcg uses memory from */
1674 memcg->scan_nodes = node_states[N_MEMORY];
1676 for_each_node_mask(nid, node_states[N_MEMORY]) {
1678 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1679 node_clear(nid, memcg->scan_nodes);
1682 atomic_set(&memcg->numainfo_events, 0);
1683 atomic_set(&memcg->numainfo_updating, 0);
1687 * Selecting a node where we start reclaim from. Because what we need is just
1688 * reducing usage counter, start from anywhere is O,K. Considering
1689 * memory reclaim from current node, there are pros. and cons.
1691 * Freeing memory from current node means freeing memory from a node which
1692 * we'll use or we've used. So, it may make LRU bad. And if several threads
1693 * hit limits, it will see a contention on a node. But freeing from remote
1694 * node means more costs for memory reclaim because of memory latency.
1696 * Now, we use round-robin. Better algorithm is welcomed.
1698 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1702 mem_cgroup_may_update_nodemask(memcg);
1703 node = memcg->last_scanned_node;
1705 node = next_node(node, memcg->scan_nodes);
1706 if (node == MAX_NUMNODES)
1707 node = first_node(memcg->scan_nodes);
1709 * We call this when we hit limit, not when pages are added to LRU.
1710 * No LRU may hold pages because all pages are UNEVICTABLE or
1711 * memcg is too small and all pages are not on LRU. In that case,
1712 * we use curret node.
1714 if (unlikely(node == MAX_NUMNODES))
1715 node = numa_node_id();
1717 memcg->last_scanned_node = node;
1721 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1727 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1730 unsigned long *total_scanned)
1732 struct mem_cgroup *victim = NULL;
1735 unsigned long excess;
1736 unsigned long nr_scanned;
1737 struct mem_cgroup_reclaim_cookie reclaim = {
1742 excess = soft_limit_excess(root_memcg);
1745 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1750 * If we have not been able to reclaim
1751 * anything, it might because there are
1752 * no reclaimable pages under this hierarchy
1757 * We want to do more targeted reclaim.
1758 * excess >> 2 is not to excessive so as to
1759 * reclaim too much, nor too less that we keep
1760 * coming back to reclaim from this cgroup
1762 if (total >= (excess >> 2) ||
1763 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1768 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
1770 *total_scanned += nr_scanned;
1771 if (!soft_limit_excess(root_memcg))
1774 mem_cgroup_iter_break(root_memcg, victim);
1778 #ifdef CONFIG_LOCKDEP
1779 static struct lockdep_map memcg_oom_lock_dep_map = {
1780 .name = "memcg_oom_lock",
1784 static DEFINE_SPINLOCK(memcg_oom_lock);
1787 * Check OOM-Killer is already running under our hierarchy.
1788 * If someone is running, return false.
1790 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1792 struct mem_cgroup *iter, *failed = NULL;
1794 spin_lock(&memcg_oom_lock);
1796 for_each_mem_cgroup_tree(iter, memcg) {
1797 if (iter->oom_lock) {
1799 * this subtree of our hierarchy is already locked
1800 * so we cannot give a lock.
1803 mem_cgroup_iter_break(memcg, iter);
1806 iter->oom_lock = true;
1811 * OK, we failed to lock the whole subtree so we have
1812 * to clean up what we set up to the failing subtree
1814 for_each_mem_cgroup_tree(iter, memcg) {
1815 if (iter == failed) {
1816 mem_cgroup_iter_break(memcg, iter);
1819 iter->oom_lock = false;
1822 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1824 spin_unlock(&memcg_oom_lock);
1829 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1831 struct mem_cgroup *iter;
1833 spin_lock(&memcg_oom_lock);
1834 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
1835 for_each_mem_cgroup_tree(iter, memcg)
1836 iter->oom_lock = false;
1837 spin_unlock(&memcg_oom_lock);
1840 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1842 struct mem_cgroup *iter;
1844 for_each_mem_cgroup_tree(iter, memcg)
1845 atomic_inc(&iter->under_oom);
1848 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1850 struct mem_cgroup *iter;
1853 * When a new child is created while the hierarchy is under oom,
1854 * mem_cgroup_oom_lock() may not be called. We have to use
1855 * atomic_add_unless() here.
1857 for_each_mem_cgroup_tree(iter, memcg)
1858 atomic_add_unless(&iter->under_oom, -1, 0);
1861 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1863 struct oom_wait_info {
1864 struct mem_cgroup *memcg;
1868 static int memcg_oom_wake_function(wait_queue_t *wait,
1869 unsigned mode, int sync, void *arg)
1871 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1872 struct mem_cgroup *oom_wait_memcg;
1873 struct oom_wait_info *oom_wait_info;
1875 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1876 oom_wait_memcg = oom_wait_info->memcg;
1878 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1879 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1881 return autoremove_wake_function(wait, mode, sync, arg);
1884 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1886 atomic_inc(&memcg->oom_wakeups);
1887 /* for filtering, pass "memcg" as argument. */
1888 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1891 static void memcg_oom_recover(struct mem_cgroup *memcg)
1893 if (memcg && atomic_read(&memcg->under_oom))
1894 memcg_wakeup_oom(memcg);
1897 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1899 if (!current->memcg_oom.may_oom)
1902 * We are in the middle of the charge context here, so we
1903 * don't want to block when potentially sitting on a callstack
1904 * that holds all kinds of filesystem and mm locks.
1906 * Also, the caller may handle a failed allocation gracefully
1907 * (like optional page cache readahead) and so an OOM killer
1908 * invocation might not even be necessary.
1910 * That's why we don't do anything here except remember the
1911 * OOM context and then deal with it at the end of the page
1912 * fault when the stack is unwound, the locks are released,
1913 * and when we know whether the fault was overall successful.
1915 css_get(&memcg->css);
1916 current->memcg_oom.memcg = memcg;
1917 current->memcg_oom.gfp_mask = mask;
1918 current->memcg_oom.order = order;
1922 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1923 * @handle: actually kill/wait or just clean up the OOM state
1925 * This has to be called at the end of a page fault if the memcg OOM
1926 * handler was enabled.
1928 * Memcg supports userspace OOM handling where failed allocations must
1929 * sleep on a waitqueue until the userspace task resolves the
1930 * situation. Sleeping directly in the charge context with all kinds
1931 * of locks held is not a good idea, instead we remember an OOM state
1932 * in the task and mem_cgroup_oom_synchronize() has to be called at
1933 * the end of the page fault to complete the OOM handling.
1935 * Returns %true if an ongoing memcg OOM situation was detected and
1936 * completed, %false otherwise.
1938 bool mem_cgroup_oom_synchronize(bool handle)
1940 struct mem_cgroup *memcg = current->memcg_oom.memcg;
1941 struct oom_wait_info owait;
1944 /* OOM is global, do not handle */
1951 owait.memcg = memcg;
1952 owait.wait.flags = 0;
1953 owait.wait.func = memcg_oom_wake_function;
1954 owait.wait.private = current;
1955 INIT_LIST_HEAD(&owait.wait.task_list);
1957 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1958 mem_cgroup_mark_under_oom(memcg);
1960 locked = mem_cgroup_oom_trylock(memcg);
1963 mem_cgroup_oom_notify(memcg);
1965 if (locked && !memcg->oom_kill_disable) {
1966 mem_cgroup_unmark_under_oom(memcg);
1967 finish_wait(&memcg_oom_waitq, &owait.wait);
1968 mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
1969 current->memcg_oom.order);
1972 mem_cgroup_unmark_under_oom(memcg);
1973 finish_wait(&memcg_oom_waitq, &owait.wait);
1977 mem_cgroup_oom_unlock(memcg);
1979 * There is no guarantee that an OOM-lock contender
1980 * sees the wakeups triggered by the OOM kill
1981 * uncharges. Wake any sleepers explicitely.
1983 memcg_oom_recover(memcg);
1986 current->memcg_oom.memcg = NULL;
1987 css_put(&memcg->css);
1992 * mem_cgroup_begin_page_stat - begin a page state statistics transaction
1993 * @page: page that is going to change accounted state
1994 * @locked: &memcg->move_lock slowpath was taken
1995 * @flags: IRQ-state flags for &memcg->move_lock
1997 * This function must mark the beginning of an accounted page state
1998 * change to prevent double accounting when the page is concurrently
1999 * being moved to another memcg:
2001 * memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
2002 * if (TestClearPageState(page))
2003 * mem_cgroup_update_page_stat(memcg, state, -1);
2004 * mem_cgroup_end_page_stat(memcg, locked, flags);
2006 * The RCU lock is held throughout the transaction. The fast path can
2007 * get away without acquiring the memcg->move_lock (@locked is false)
2008 * because page moving starts with an RCU grace period.
2010 * The RCU lock also protects the memcg from being freed when the page
2011 * state that is going to change is the only thing preventing the page
2012 * from being uncharged. E.g. end-writeback clearing PageWriteback(),
2013 * which allows migration to go ahead and uncharge the page before the
2014 * account transaction might be complete.
2016 struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page,
2018 unsigned long *flags)
2020 struct mem_cgroup *memcg;
2024 if (mem_cgroup_disabled())
2027 memcg = page->mem_cgroup;
2028 if (unlikely(!memcg))
2032 if (atomic_read(&memcg->moving_account) <= 0)
2035 spin_lock_irqsave(&memcg->move_lock, *flags);
2036 if (memcg != page->mem_cgroup) {
2037 spin_unlock_irqrestore(&memcg->move_lock, *flags);
2046 * mem_cgroup_end_page_stat - finish a page state statistics transaction
2047 * @memcg: the memcg that was accounted against
2048 * @locked: value received from mem_cgroup_begin_page_stat()
2049 * @flags: value received from mem_cgroup_begin_page_stat()
2051 void mem_cgroup_end_page_stat(struct mem_cgroup *memcg, bool *locked,
2052 unsigned long *flags)
2054 if (memcg && *locked)
2055 spin_unlock_irqrestore(&memcg->move_lock, *flags);
2061 * mem_cgroup_update_page_stat - update page state statistics
2062 * @memcg: memcg to account against
2063 * @idx: page state item to account
2064 * @val: number of pages (positive or negative)
2066 * See mem_cgroup_begin_page_stat() for locking requirements.
2068 void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
2069 enum mem_cgroup_stat_index idx, int val)
2071 VM_BUG_ON(!rcu_read_lock_held());
2074 this_cpu_add(memcg->stat->count[idx], val);
2078 * size of first charge trial. "32" comes from vmscan.c's magic value.
2079 * TODO: maybe necessary to use big numbers in big irons.
2081 #define CHARGE_BATCH 32U
2082 struct memcg_stock_pcp {
2083 struct mem_cgroup *cached; /* this never be root cgroup */
2084 unsigned int nr_pages;
2085 struct work_struct work;
2086 unsigned long flags;
2087 #define FLUSHING_CACHED_CHARGE 0
2089 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2090 static DEFINE_MUTEX(percpu_charge_mutex);
2093 * consume_stock: Try to consume stocked charge on this cpu.
2094 * @memcg: memcg to consume from.
2095 * @nr_pages: how many pages to charge.
2097 * The charges will only happen if @memcg matches the current cpu's memcg
2098 * stock, and at least @nr_pages are available in that stock. Failure to
2099 * service an allocation will refill the stock.
2101 * returns true if successful, false otherwise.
2103 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2105 struct memcg_stock_pcp *stock;
2108 if (nr_pages > CHARGE_BATCH)
2111 stock = &get_cpu_var(memcg_stock);
2112 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
2113 stock->nr_pages -= nr_pages;
2116 put_cpu_var(memcg_stock);
2121 * Returns stocks cached in percpu and reset cached information.
2123 static void drain_stock(struct memcg_stock_pcp *stock)
2125 struct mem_cgroup *old = stock->cached;
2127 if (stock->nr_pages) {
2128 page_counter_uncharge(&old->memory, stock->nr_pages);
2129 if (do_swap_account)
2130 page_counter_uncharge(&old->memsw, stock->nr_pages);
2131 css_put_many(&old->css, stock->nr_pages);
2132 stock->nr_pages = 0;
2134 stock->cached = NULL;
2138 * This must be called under preempt disabled or must be called by
2139 * a thread which is pinned to local cpu.
2141 static void drain_local_stock(struct work_struct *dummy)
2143 struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
2145 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2148 static void __init memcg_stock_init(void)
2152 for_each_possible_cpu(cpu) {
2153 struct memcg_stock_pcp *stock =
2154 &per_cpu(memcg_stock, cpu);
2155 INIT_WORK(&stock->work, drain_local_stock);
2160 * Cache charges(val) to local per_cpu area.
2161 * This will be consumed by consume_stock() function, later.
2163 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2165 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2167 if (stock->cached != memcg) { /* reset if necessary */
2169 stock->cached = memcg;
2171 stock->nr_pages += nr_pages;
2172 put_cpu_var(memcg_stock);
2176 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2177 * of the hierarchy under it.
2179 static void drain_all_stock(struct mem_cgroup *root_memcg)
2183 /* If someone's already draining, avoid adding running more workers. */
2184 if (!mutex_trylock(&percpu_charge_mutex))
2186 /* Notify other cpus that system-wide "drain" is running */
2189 for_each_online_cpu(cpu) {
2190 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2191 struct mem_cgroup *memcg;
2193 memcg = stock->cached;
2194 if (!memcg || !stock->nr_pages)
2196 if (!mem_cgroup_is_descendant(memcg, root_memcg))
2198 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2200 drain_local_stock(&stock->work);
2202 schedule_work_on(cpu, &stock->work);
2207 mutex_unlock(&percpu_charge_mutex);
2211 * This function drains percpu counter value from DEAD cpu and
2212 * move it to local cpu. Note that this function can be preempted.
2214 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2218 spin_lock(&memcg->pcp_counter_lock);
2219 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2220 long x = per_cpu(memcg->stat->count[i], cpu);
2222 per_cpu(memcg->stat->count[i], cpu) = 0;
2223 memcg->nocpu_base.count[i] += x;
2225 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2226 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2228 per_cpu(memcg->stat->events[i], cpu) = 0;
2229 memcg->nocpu_base.events[i] += x;
2231 spin_unlock(&memcg->pcp_counter_lock);
2234 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2235 unsigned long action,
2238 int cpu = (unsigned long)hcpu;
2239 struct memcg_stock_pcp *stock;
2240 struct mem_cgroup *iter;
2242 if (action == CPU_ONLINE)
2245 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2248 for_each_mem_cgroup(iter)
2249 mem_cgroup_drain_pcp_counter(iter, cpu);
2251 stock = &per_cpu(memcg_stock, cpu);
2256 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2257 unsigned int nr_pages)
2259 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2260 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2261 struct mem_cgroup *mem_over_limit;
2262 struct page_counter *counter;
2263 unsigned long nr_reclaimed;
2264 bool may_swap = true;
2265 bool drained = false;
2268 if (mem_cgroup_is_root(memcg))
2271 if (consume_stock(memcg, nr_pages))
2274 if (!do_swap_account ||
2275 !page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2276 if (!page_counter_try_charge(&memcg->memory, batch, &counter))
2278 if (do_swap_account)
2279 page_counter_uncharge(&memcg->memsw, batch);
2280 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2282 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2286 if (batch > nr_pages) {
2292 * Unlike in global OOM situations, memcg is not in a physical
2293 * memory shortage. Allow dying and OOM-killed tasks to
2294 * bypass the last charges so that they can exit quickly and
2295 * free their memory.
2297 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
2298 fatal_signal_pending(current) ||
2299 current->flags & PF_EXITING))
2302 if (unlikely(task_in_memcg_oom(current)))
2305 if (!(gfp_mask & __GFP_WAIT))
2308 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2309 gfp_mask, may_swap);
2311 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2315 drain_all_stock(mem_over_limit);
2320 if (gfp_mask & __GFP_NORETRY)
2323 * Even though the limit is exceeded at this point, reclaim
2324 * may have been able to free some pages. Retry the charge
2325 * before killing the task.
2327 * Only for regular pages, though: huge pages are rather
2328 * unlikely to succeed so close to the limit, and we fall back
2329 * to regular pages anyway in case of failure.
2331 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
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))
2343 if (gfp_mask & __GFP_NOFAIL)
2346 if (fatal_signal_pending(current))
2349 mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages));
2351 if (!(gfp_mask & __GFP_NOFAIL))
2357 css_get_many(&memcg->css, batch);
2358 if (batch > nr_pages)
2359 refill_stock(memcg, batch - nr_pages);
2364 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2366 if (mem_cgroup_is_root(memcg))
2369 page_counter_uncharge(&memcg->memory, nr_pages);
2370 if (do_swap_account)
2371 page_counter_uncharge(&memcg->memsw, nr_pages);
2373 css_put_many(&memcg->css, nr_pages);
2377 * A helper function to get mem_cgroup from ID. must be called under
2378 * rcu_read_lock(). The caller is responsible for calling
2379 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2380 * refcnt from swap can be called against removed memcg.)
2382 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2384 /* ID 0 is unused ID */
2387 return mem_cgroup_from_id(id);
2391 * try_get_mem_cgroup_from_page - look up page's memcg association
2394 * Look up, get a css reference, and return the memcg that owns @page.
2396 * The page must be locked to prevent racing with swap-in and page
2397 * cache charges. If coming from an unlocked page table, the caller
2398 * must ensure the page is on the LRU or this can race with charging.
2400 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2402 struct mem_cgroup *memcg;
2406 VM_BUG_ON_PAGE(!PageLocked(page), page);
2408 memcg = page->mem_cgroup;
2410 if (!css_tryget_online(&memcg->css))
2412 } else if (PageSwapCache(page)) {
2413 ent.val = page_private(page);
2414 id = lookup_swap_cgroup_id(ent);
2416 memcg = mem_cgroup_lookup(id);
2417 if (memcg && !css_tryget_online(&memcg->css))
2424 static void lock_page_lru(struct page *page, int *isolated)
2426 struct zone *zone = page_zone(page);
2428 spin_lock_irq(&zone->lru_lock);
2429 if (PageLRU(page)) {
2430 struct lruvec *lruvec;
2432 lruvec = mem_cgroup_page_lruvec(page, zone);
2434 del_page_from_lru_list(page, lruvec, page_lru(page));
2440 static void unlock_page_lru(struct page *page, int isolated)
2442 struct zone *zone = page_zone(page);
2445 struct lruvec *lruvec;
2447 lruvec = mem_cgroup_page_lruvec(page, zone);
2448 VM_BUG_ON_PAGE(PageLRU(page), page);
2450 add_page_to_lru_list(page, lruvec, page_lru(page));
2452 spin_unlock_irq(&zone->lru_lock);
2455 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2460 VM_BUG_ON_PAGE(page->mem_cgroup, page);
2463 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2464 * may already be on some other mem_cgroup's LRU. Take care of it.
2467 lock_page_lru(page, &isolated);
2470 * Nobody should be changing or seriously looking at
2471 * page->mem_cgroup at this point:
2473 * - the page is uncharged
2475 * - the page is off-LRU
2477 * - an anonymous fault has exclusive page access, except for
2478 * a locked page table
2480 * - a page cache insertion, a swapin fault, or a migration
2481 * have the page locked
2483 page->mem_cgroup = memcg;
2486 unlock_page_lru(page, isolated);
2489 #ifdef CONFIG_MEMCG_KMEM
2491 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2492 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2494 static DEFINE_MUTEX(memcg_slab_mutex);
2497 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2498 * in the memcg_cache_params struct.
2500 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2502 struct kmem_cache *cachep;
2504 VM_BUG_ON(p->is_root_cache);
2505 cachep = p->root_cache;
2506 return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
2509 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
2510 unsigned long nr_pages)
2512 struct page_counter *counter;
2515 ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter);
2519 ret = try_charge(memcg, gfp, nr_pages);
2520 if (ret == -EINTR) {
2522 * try_charge() chose to bypass to root due to OOM kill or
2523 * fatal signal. Since our only options are to either fail
2524 * the allocation or charge it to this cgroup, do it as a
2525 * temporary condition. But we can't fail. From a kmem/slab
2526 * perspective, the cache has already been selected, by
2527 * mem_cgroup_kmem_get_cache(), so it is too late to change
2530 * This condition will only trigger if the task entered
2531 * memcg_charge_kmem in a sane state, but was OOM-killed
2532 * during try_charge() above. Tasks that were already dying
2533 * when the allocation triggers should have been already
2534 * directed to the root cgroup in memcontrol.h
2536 page_counter_charge(&memcg->memory, nr_pages);
2537 if (do_swap_account)
2538 page_counter_charge(&memcg->memsw, nr_pages);
2539 css_get_many(&memcg->css, nr_pages);
2542 page_counter_uncharge(&memcg->kmem, nr_pages);
2547 static void memcg_uncharge_kmem(struct mem_cgroup *memcg,
2548 unsigned long nr_pages)
2550 page_counter_uncharge(&memcg->memory, nr_pages);
2551 if (do_swap_account)
2552 page_counter_uncharge(&memcg->memsw, nr_pages);
2554 page_counter_uncharge(&memcg->kmem, nr_pages);
2556 css_put_many(&memcg->css, nr_pages);
2560 * helper for acessing a memcg's index. It will be used as an index in the
2561 * child cache array in kmem_cache, and also to derive its name. This function
2562 * will return -1 when this is not a kmem-limited memcg.
2564 int memcg_cache_id(struct mem_cgroup *memcg)
2566 return memcg ? memcg->kmemcg_id : -1;
2569 static int memcg_alloc_cache_id(void)
2574 id = ida_simple_get(&kmem_limited_groups,
2575 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2579 if (id < memcg_limited_groups_array_size)
2583 * There's no space for the new id in memcg_caches arrays,
2584 * so we have to grow them.
2587 size = 2 * (id + 1);
2588 if (size < MEMCG_CACHES_MIN_SIZE)
2589 size = MEMCG_CACHES_MIN_SIZE;
2590 else if (size > MEMCG_CACHES_MAX_SIZE)
2591 size = MEMCG_CACHES_MAX_SIZE;
2593 mutex_lock(&memcg_slab_mutex);
2594 err = memcg_update_all_caches(size);
2595 mutex_unlock(&memcg_slab_mutex);
2598 ida_simple_remove(&kmem_limited_groups, id);
2604 static void memcg_free_cache_id(int id)
2606 ida_simple_remove(&kmem_limited_groups, id);
2610 * We should update the current array size iff all caches updates succeed. This
2611 * can only be done from the slab side. The slab mutex needs to be held when
2614 void memcg_update_array_size(int num)
2616 memcg_limited_groups_array_size = num;
2619 static void memcg_register_cache(struct mem_cgroup *memcg,
2620 struct kmem_cache *root_cache)
2622 static char memcg_name_buf[NAME_MAX + 1]; /* protected by
2624 struct kmem_cache *cachep;
2627 lockdep_assert_held(&memcg_slab_mutex);
2629 id = memcg_cache_id(memcg);
2632 * Since per-memcg caches are created asynchronously on first
2633 * allocation (see memcg_kmem_get_cache()), several threads can try to
2634 * create the same cache, but only one of them may succeed.
2636 if (cache_from_memcg_idx(root_cache, id))
2639 cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
2640 cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
2642 * If we could not create a memcg cache, do not complain, because
2643 * that's not critical at all as we can always proceed with the root
2649 css_get(&memcg->css);
2650 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
2653 * Since readers won't lock (see cache_from_memcg_idx()), we need a
2654 * barrier here to ensure nobody will see the kmem_cache partially
2659 BUG_ON(root_cache->memcg_params->memcg_caches[id]);
2660 root_cache->memcg_params->memcg_caches[id] = cachep;
2663 static void memcg_unregister_cache(struct kmem_cache *cachep)
2665 struct kmem_cache *root_cache;
2666 struct mem_cgroup *memcg;
2669 lockdep_assert_held(&memcg_slab_mutex);
2671 BUG_ON(is_root_cache(cachep));
2673 root_cache = cachep->memcg_params->root_cache;
2674 memcg = cachep->memcg_params->memcg;
2675 id = memcg_cache_id(memcg);
2677 BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
2678 root_cache->memcg_params->memcg_caches[id] = NULL;
2680 list_del(&cachep->memcg_params->list);
2682 kmem_cache_destroy(cachep);
2684 /* drop the reference taken in memcg_register_cache */
2685 css_put(&memcg->css);
2689 * During the creation a new cache, we need to disable our accounting mechanism
2690 * altogether. This is true even if we are not creating, but rather just
2691 * enqueing new caches to be created.
2693 * This is because that process will trigger allocations; some visible, like
2694 * explicit kmallocs to auxiliary data structures, name strings and internal
2695 * cache structures; some well concealed, like INIT_WORK() that can allocate
2696 * objects during debug.
2698 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
2699 * to it. This may not be a bounded recursion: since the first cache creation
2700 * failed to complete (waiting on the allocation), we'll just try to create the
2701 * cache again, failing at the same point.
2703 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
2704 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
2705 * inside the following two functions.
2707 static inline void memcg_stop_kmem_account(void)
2709 VM_BUG_ON(!current->mm);
2710 current->memcg_kmem_skip_account++;
2713 static inline void memcg_resume_kmem_account(void)
2715 VM_BUG_ON(!current->mm);
2716 current->memcg_kmem_skip_account--;
2719 int __memcg_cleanup_cache_params(struct kmem_cache *s)
2721 struct kmem_cache *c;
2724 mutex_lock(&memcg_slab_mutex);
2725 for_each_memcg_cache_index(i) {
2726 c = cache_from_memcg_idx(s, i);
2730 memcg_unregister_cache(c);
2732 if (cache_from_memcg_idx(s, i))
2735 mutex_unlock(&memcg_slab_mutex);
2739 static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
2741 struct kmem_cache *cachep;
2742 struct memcg_cache_params *params, *tmp;
2744 if (!memcg_kmem_is_active(memcg))
2747 mutex_lock(&memcg_slab_mutex);
2748 list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
2749 cachep = memcg_params_to_cache(params);
2750 kmem_cache_shrink(cachep);
2751 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
2752 memcg_unregister_cache(cachep);
2754 mutex_unlock(&memcg_slab_mutex);
2757 struct memcg_register_cache_work {
2758 struct mem_cgroup *memcg;
2759 struct kmem_cache *cachep;
2760 struct work_struct work;
2763 static void memcg_register_cache_func(struct work_struct *w)
2765 struct memcg_register_cache_work *cw =
2766 container_of(w, struct memcg_register_cache_work, work);
2767 struct mem_cgroup *memcg = cw->memcg;
2768 struct kmem_cache *cachep = cw->cachep;
2770 mutex_lock(&memcg_slab_mutex);
2771 memcg_register_cache(memcg, cachep);
2772 mutex_unlock(&memcg_slab_mutex);
2774 css_put(&memcg->css);
2779 * Enqueue the creation of a per-memcg kmem_cache.
2781 static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
2782 struct kmem_cache *cachep)
2784 struct memcg_register_cache_work *cw;
2786 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
2788 css_put(&memcg->css);
2793 cw->cachep = cachep;
2795 INIT_WORK(&cw->work, memcg_register_cache_func);
2796 schedule_work(&cw->work);
2799 static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
2800 struct kmem_cache *cachep)
2803 * We need to stop accounting when we kmalloc, because if the
2804 * corresponding kmalloc cache is not yet created, the first allocation
2805 * in __memcg_schedule_register_cache will recurse.
2807 * However, it is better to enclose the whole function. Depending on
2808 * the debugging options enabled, INIT_WORK(), for instance, can
2809 * trigger an allocation. This too, will make us recurse. Because at
2810 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2811 * the safest choice is to do it like this, wrapping the whole function.
2813 memcg_stop_kmem_account();
2814 __memcg_schedule_register_cache(memcg, cachep);
2815 memcg_resume_kmem_account();
2818 int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
2820 unsigned int nr_pages = 1 << order;
2823 res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp, nr_pages);
2825 atomic_add(nr_pages, &cachep->memcg_params->nr_pages);
2829 void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
2831 unsigned int nr_pages = 1 << order;
2833 memcg_uncharge_kmem(cachep->memcg_params->memcg, nr_pages);
2834 atomic_sub(nr_pages, &cachep->memcg_params->nr_pages);
2838 * Return the kmem_cache we're supposed to use for a slab allocation.
2839 * We try to use the current memcg's version of the cache.
2841 * If the cache does not exist yet, if we are the first user of it,
2842 * we either create it immediately, if possible, or create it asynchronously
2844 * In the latter case, we will let the current allocation go through with
2845 * the original cache.
2847 * Can't be called in interrupt context or from kernel threads.
2848 * This function needs to be called with rcu_read_lock() held.
2850 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
2853 struct mem_cgroup *memcg;
2854 struct kmem_cache *memcg_cachep;
2856 VM_BUG_ON(!cachep->memcg_params);
2857 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
2859 if (!current->mm || current->memcg_kmem_skip_account)
2863 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
2865 if (!memcg_kmem_is_active(memcg))
2868 memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
2869 if (likely(memcg_cachep)) {
2870 cachep = memcg_cachep;
2874 /* The corresponding put will be done in the workqueue. */
2875 if (!css_tryget_online(&memcg->css))
2880 * If we are in a safe context (can wait, and not in interrupt
2881 * context), we could be be predictable and return right away.
2882 * This would guarantee that the allocation being performed
2883 * already belongs in the new cache.
2885 * However, there are some clashes that can arrive from locking.
2886 * For instance, because we acquire the slab_mutex while doing
2887 * memcg_create_kmem_cache, this means no further allocation
2888 * could happen with the slab_mutex held. So it's better to
2891 memcg_schedule_register_cache(memcg, cachep);
2899 * We need to verify if the allocation against current->mm->owner's memcg is
2900 * possible for the given order. But the page is not allocated yet, so we'll
2901 * need a further commit step to do the final arrangements.
2903 * It is possible for the task to switch cgroups in this mean time, so at
2904 * commit time, we can't rely on task conversion any longer. We'll then use
2905 * the handle argument to return to the caller which cgroup we should commit
2906 * against. We could also return the memcg directly and avoid the pointer
2907 * passing, but a boolean return value gives better semantics considering
2908 * the compiled-out case as well.
2910 * Returning true means the allocation is possible.
2913 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
2915 struct mem_cgroup *memcg;
2921 * Disabling accounting is only relevant for some specific memcg
2922 * internal allocations. Therefore we would initially not have such
2923 * check here, since direct calls to the page allocator that are
2924 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
2925 * outside memcg core. We are mostly concerned with cache allocations,
2926 * and by having this test at memcg_kmem_get_cache, we are already able
2927 * to relay the allocation to the root cache and bypass the memcg cache
2930 * There is one exception, though: the SLUB allocator does not create
2931 * large order caches, but rather service large kmallocs directly from
2932 * the page allocator. Therefore, the following sequence when backed by
2933 * the SLUB allocator:
2935 * memcg_stop_kmem_account();
2936 * kmalloc(<large_number>)
2937 * memcg_resume_kmem_account();
2939 * would effectively ignore the fact that we should skip accounting,
2940 * since it will drive us directly to this function without passing
2941 * through the cache selector memcg_kmem_get_cache. Such large
2942 * allocations are extremely rare but can happen, for instance, for the
2943 * cache arrays. We bring this test here.
2945 if (!current->mm || current->memcg_kmem_skip_account)
2948 memcg = get_mem_cgroup_from_mm(current->mm);
2950 if (!memcg_kmem_is_active(memcg)) {
2951 css_put(&memcg->css);
2955 ret = memcg_charge_kmem(memcg, gfp, 1 << order);
2959 css_put(&memcg->css);
2963 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
2966 VM_BUG_ON(mem_cgroup_is_root(memcg));
2968 /* The page allocation failed. Revert */
2970 memcg_uncharge_kmem(memcg, 1 << order);
2973 page->mem_cgroup = memcg;
2976 void __memcg_kmem_uncharge_pages(struct page *page, int order)
2978 struct mem_cgroup *memcg = page->mem_cgroup;
2983 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
2985 memcg_uncharge_kmem(memcg, 1 << order);
2986 page->mem_cgroup = NULL;
2989 static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
2992 #endif /* CONFIG_MEMCG_KMEM */
2994 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2997 * Because tail pages are not marked as "used", set it. We're under
2998 * zone->lru_lock, 'splitting on pmd' and compound_lock.
2999 * charge/uncharge will be never happen and move_account() is done under
3000 * compound_lock(), so we don't have to take care of races.
3002 void mem_cgroup_split_huge_fixup(struct page *head)
3006 if (mem_cgroup_disabled())
3009 for (i = 1; i < HPAGE_PMD_NR; i++)
3010 head[i].mem_cgroup = head->mem_cgroup;
3012 __this_cpu_sub(head->mem_cgroup->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3015 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3018 * mem_cgroup_move_account - move account of the page
3020 * @nr_pages: number of regular pages (>1 for huge pages)
3021 * @from: mem_cgroup which the page is moved from.
3022 * @to: mem_cgroup which the page is moved to. @from != @to.
3024 * The caller must confirm following.
3025 * - page is not on LRU (isolate_page() is useful.)
3026 * - compound_lock is held when nr_pages > 1
3028 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3031 static int mem_cgroup_move_account(struct page *page,
3032 unsigned int nr_pages,
3033 struct mem_cgroup *from,
3034 struct mem_cgroup *to)
3036 unsigned long flags;
3039 VM_BUG_ON(from == to);
3040 VM_BUG_ON_PAGE(PageLRU(page), page);
3042 * The page is isolated from LRU. So, collapse function
3043 * will not handle this page. But page splitting can happen.
3044 * Do this check under compound_page_lock(). The caller should
3048 if (nr_pages > 1 && !PageTransHuge(page))
3052 * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup
3053 * of its source page while we change it: page migration takes
3054 * both pages off the LRU, but page cache replacement doesn't.
3056 if (!trylock_page(page))
3060 if (page->mem_cgroup != from)
3063 spin_lock_irqsave(&from->move_lock, flags);
3065 if (!PageAnon(page) && page_mapped(page)) {
3066 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3068 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3072 if (PageWriteback(page)) {
3073 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3075 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3080 * It is safe to change page->mem_cgroup here because the page
3081 * is referenced, charged, and isolated - we can't race with
3082 * uncharging, charging, migration, or LRU putback.
3085 /* caller should have done css_get */
3086 page->mem_cgroup = to;
3087 spin_unlock_irqrestore(&from->move_lock, flags);
3091 local_irq_disable();
3092 mem_cgroup_charge_statistics(to, page, nr_pages);
3093 memcg_check_events(to, page);
3094 mem_cgroup_charge_statistics(from, page, -nr_pages);
3095 memcg_check_events(from, page);
3103 #ifdef CONFIG_MEMCG_SWAP
3104 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
3107 int val = (charge) ? 1 : -1;
3108 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
3112 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3113 * @entry: swap entry to be moved
3114 * @from: mem_cgroup which the entry is moved from
3115 * @to: mem_cgroup which the entry is moved to
3117 * It succeeds only when the swap_cgroup's record for this entry is the same
3118 * as the mem_cgroup's id of @from.
3120 * Returns 0 on success, -EINVAL on failure.
3122 * The caller must have charged to @to, IOW, called page_counter_charge() about
3123 * both res and memsw, and called css_get().
3125 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3126 struct mem_cgroup *from, struct mem_cgroup *to)
3128 unsigned short old_id, new_id;
3130 old_id = mem_cgroup_id(from);
3131 new_id = mem_cgroup_id(to);
3133 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3134 mem_cgroup_swap_statistics(from, false);
3135 mem_cgroup_swap_statistics(to, true);
3137 * This function is only called from task migration context now.
3138 * It postpones page_counter and refcount handling till the end
3139 * of task migration(mem_cgroup_clear_mc()) for performance
3140 * improvement. But we cannot postpone css_get(to) because if
3141 * the process that has been moved to @to does swap-in, the
3142 * refcount of @to might be decreased to 0.
3144 * We are in attach() phase, so the cgroup is guaranteed to be
3145 * alive, so we can just call css_get().
3153 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3154 struct mem_cgroup *from, struct mem_cgroup *to)
3160 #ifdef CONFIG_DEBUG_VM
3161 bool mem_cgroup_bad_page_check(struct page *page)
3163 if (mem_cgroup_disabled())
3166 return page->mem_cgroup != NULL;
3169 void mem_cgroup_print_bad_page(struct page *page)
3171 pr_alert("page->mem_cgroup:%p\n", page->mem_cgroup);
3175 static DEFINE_MUTEX(memcg_limit_mutex);
3177 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3178 unsigned long limit)
3180 unsigned long curusage;
3181 unsigned long oldusage;
3182 bool enlarge = false;
3187 * For keeping hierarchical_reclaim simple, how long we should retry
3188 * is depends on callers. We set our retry-count to be function
3189 * of # of children which we should visit in this loop.
3191 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
3192 mem_cgroup_count_children(memcg);
3194 oldusage = page_counter_read(&memcg->memory);
3197 if (signal_pending(current)) {
3202 mutex_lock(&memcg_limit_mutex);
3203 if (limit > memcg->memsw.limit) {
3204 mutex_unlock(&memcg_limit_mutex);
3208 if (limit > memcg->memory.limit)
3210 ret = page_counter_limit(&memcg->memory, limit);
3211 mutex_unlock(&memcg_limit_mutex);
3216 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
3218 curusage = page_counter_read(&memcg->memory);
3219 /* Usage is reduced ? */
3220 if (curusage >= oldusage)
3223 oldusage = curusage;
3224 } while (retry_count);
3226 if (!ret && enlarge)
3227 memcg_oom_recover(memcg);
3232 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3233 unsigned long limit)
3235 unsigned long curusage;
3236 unsigned long oldusage;
3237 bool enlarge = false;
3241 /* see mem_cgroup_resize_res_limit */
3242 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
3243 mem_cgroup_count_children(memcg);
3245 oldusage = page_counter_read(&memcg->memsw);
3248 if (signal_pending(current)) {
3253 mutex_lock(&memcg_limit_mutex);
3254 if (limit < memcg->memory.limit) {
3255 mutex_unlock(&memcg_limit_mutex);
3259 if (limit > memcg->memsw.limit)
3261 ret = page_counter_limit(&memcg->memsw, limit);
3262 mutex_unlock(&memcg_limit_mutex);
3267 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
3269 curusage = page_counter_read(&memcg->memsw);
3270 /* Usage is reduced ? */
3271 if (curusage >= oldusage)
3274 oldusage = curusage;
3275 } while (retry_count);
3277 if (!ret && enlarge)
3278 memcg_oom_recover(memcg);
3283 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3285 unsigned long *total_scanned)
3287 unsigned long nr_reclaimed = 0;
3288 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3289 unsigned long reclaimed;
3291 struct mem_cgroup_tree_per_zone *mctz;
3292 unsigned long excess;
3293 unsigned long nr_scanned;
3298 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3300 * This loop can run a while, specially if mem_cgroup's continuously
3301 * keep exceeding their soft limit and putting the system under
3308 mz = mem_cgroup_largest_soft_limit_node(mctz);
3313 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
3314 gfp_mask, &nr_scanned);
3315 nr_reclaimed += reclaimed;
3316 *total_scanned += nr_scanned;
3317 spin_lock_irq(&mctz->lock);
3318 __mem_cgroup_remove_exceeded(mz, mctz);
3321 * If we failed to reclaim anything from this memory cgroup
3322 * it is time to move on to the next cgroup
3326 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3328 excess = soft_limit_excess(mz->memcg);
3330 * One school of thought says that we should not add
3331 * back the node to the tree if reclaim returns 0.
3332 * But our reclaim could return 0, simply because due
3333 * to priority we are exposing a smaller subset of
3334 * memory to reclaim from. Consider this as a longer
3337 /* If excess == 0, no tree ops */
3338 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3339 spin_unlock_irq(&mctz->lock);
3340 css_put(&mz->memcg->css);
3343 * Could not reclaim anything and there are no more
3344 * mem cgroups to try or we seem to be looping without
3345 * reclaiming anything.
3347 if (!nr_reclaimed &&
3349 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3351 } while (!nr_reclaimed);
3353 css_put(&next_mz->memcg->css);
3354 return nr_reclaimed;
3358 * Test whether @memcg has children, dead or alive. Note that this
3359 * function doesn't care whether @memcg has use_hierarchy enabled and
3360 * returns %true if there are child csses according to the cgroup
3361 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
3363 static inline bool memcg_has_children(struct mem_cgroup *memcg)
3368 * The lock does not prevent addition or deletion of children, but
3369 * it prevents a new child from being initialized based on this
3370 * parent in css_online(), so it's enough to decide whether
3371 * hierarchically inherited attributes can still be changed or not.
3373 lockdep_assert_held(&memcg_create_mutex);
3376 ret = css_next_child(NULL, &memcg->css);
3382 * Reclaims as many pages from the given memcg as possible and moves
3383 * the rest to the parent.
3385 * Caller is responsible for holding css reference for memcg.
3387 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3389 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3391 /* we call try-to-free pages for make this cgroup empty */
3392 lru_add_drain_all();
3393 /* try to free all pages in this cgroup */
3394 while (nr_retries && page_counter_read(&memcg->memory)) {
3397 if (signal_pending(current))
3400 progress = try_to_free_mem_cgroup_pages(memcg, 1,
3404 /* maybe some writeback is necessary */
3405 congestion_wait(BLK_RW_ASYNC, HZ/10);
3413 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3414 char *buf, size_t nbytes,
3417 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3419 if (mem_cgroup_is_root(memcg))
3421 return mem_cgroup_force_empty(memcg) ?: nbytes;
3424 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3427 return mem_cgroup_from_css(css)->use_hierarchy;
3430 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3431 struct cftype *cft, u64 val)
3434 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3435 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
3437 mutex_lock(&memcg_create_mutex);
3439 if (memcg->use_hierarchy == val)
3443 * If parent's use_hierarchy is set, we can't make any modifications
3444 * in the child subtrees. If it is unset, then the change can
3445 * occur, provided the current cgroup has no children.
3447 * For the root cgroup, parent_mem is NULL, we allow value to be
3448 * set if there are no children.
3450 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3451 (val == 1 || val == 0)) {
3452 if (!memcg_has_children(memcg))
3453 memcg->use_hierarchy = val;
3460 mutex_unlock(&memcg_create_mutex);
3465 static unsigned long tree_stat(struct mem_cgroup *memcg,
3466 enum mem_cgroup_stat_index idx)
3468 struct mem_cgroup *iter;
3471 /* Per-cpu values can be negative, use a signed accumulator */
3472 for_each_mem_cgroup_tree(iter, memcg)
3473 val += mem_cgroup_read_stat(iter, idx);
3475 if (val < 0) /* race ? */
3480 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3484 if (mem_cgroup_is_root(memcg)) {
3485 val = tree_stat(memcg, MEM_CGROUP_STAT_CACHE);
3486 val += tree_stat(memcg, MEM_CGROUP_STAT_RSS);
3488 val += tree_stat(memcg, MEM_CGROUP_STAT_SWAP);
3491 val = page_counter_read(&memcg->memory);
3493 val = page_counter_read(&memcg->memsw);
3495 return val << PAGE_SHIFT;
3506 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3509 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3510 struct page_counter *counter;
3512 switch (MEMFILE_TYPE(cft->private)) {
3514 counter = &memcg->memory;
3517 counter = &memcg->memsw;
3520 counter = &memcg->kmem;
3526 switch (MEMFILE_ATTR(cft->private)) {
3528 if (counter == &memcg->memory)
3529 return mem_cgroup_usage(memcg, false);
3530 if (counter == &memcg->memsw)
3531 return mem_cgroup_usage(memcg, true);
3532 return (u64)page_counter_read(counter) * PAGE_SIZE;
3534 return (u64)counter->limit * PAGE_SIZE;
3536 return (u64)counter->watermark * PAGE_SIZE;
3538 return counter->failcnt;
3539 case RES_SOFT_LIMIT:
3540 return (u64)memcg->soft_limit * PAGE_SIZE;
3546 #ifdef CONFIG_MEMCG_KMEM
3547 static int memcg_activate_kmem(struct mem_cgroup *memcg,
3548 unsigned long nr_pages)
3553 if (memcg_kmem_is_active(memcg))
3557 * We are going to allocate memory for data shared by all memory
3558 * cgroups so let's stop accounting here.
3560 memcg_stop_kmem_account();
3563 * For simplicity, we won't allow this to be disabled. It also can't
3564 * be changed if the cgroup has children already, or if tasks had
3567 * If tasks join before we set the limit, a person looking at
3568 * kmem.usage_in_bytes will have no way to determine when it took
3569 * place, which makes the value quite meaningless.
3571 * After it first became limited, changes in the value of the limit are
3572 * of course permitted.
3574 mutex_lock(&memcg_create_mutex);
3575 if (cgroup_has_tasks(memcg->css.cgroup) ||
3576 (memcg->use_hierarchy && memcg_has_children(memcg)))
3578 mutex_unlock(&memcg_create_mutex);
3582 memcg_id = memcg_alloc_cache_id();
3588 memcg->kmemcg_id = memcg_id;
3589 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
3592 * We couldn't have accounted to this cgroup, because it hasn't got the
3593 * active bit set yet, so this should succeed.
3595 err = page_counter_limit(&memcg->kmem, nr_pages);
3598 static_key_slow_inc(&memcg_kmem_enabled_key);
3600 * Setting the active bit after enabling static branching will
3601 * guarantee no one starts accounting before all call sites are
3604 memcg_kmem_set_active(memcg);
3606 memcg_resume_kmem_account();
3610 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
3611 unsigned long limit)
3615 mutex_lock(&memcg_limit_mutex);
3616 if (!memcg_kmem_is_active(memcg))
3617 ret = memcg_activate_kmem(memcg, limit);
3619 ret = page_counter_limit(&memcg->kmem, limit);
3620 mutex_unlock(&memcg_limit_mutex);
3624 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
3627 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
3632 mutex_lock(&memcg_limit_mutex);
3634 * If the parent cgroup is not kmem-active now, it cannot be activated
3635 * after this point, because it has at least one child already.
3637 if (memcg_kmem_is_active(parent))
3638 ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
3639 mutex_unlock(&memcg_limit_mutex);
3643 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
3644 unsigned long limit)
3648 #endif /* CONFIG_MEMCG_KMEM */
3651 * The user of this function is...
3654 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3655 char *buf, size_t nbytes, loff_t off)
3657 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3658 unsigned long nr_pages;
3661 buf = strstrip(buf);
3662 ret = page_counter_memparse(buf, &nr_pages);
3666 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3668 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3672 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3674 ret = mem_cgroup_resize_limit(memcg, nr_pages);
3677 ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
3680 ret = memcg_update_kmem_limit(memcg, nr_pages);
3684 case RES_SOFT_LIMIT:
3685 memcg->soft_limit = nr_pages;
3689 return ret ?: nbytes;
3692 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3693 size_t nbytes, loff_t off)
3695 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3696 struct page_counter *counter;
3698 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3700 counter = &memcg->memory;
3703 counter = &memcg->memsw;
3706 counter = &memcg->kmem;
3712 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3714 page_counter_reset_watermark(counter);
3717 counter->failcnt = 0;
3726 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3729 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3733 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3734 struct cftype *cft, u64 val)
3736 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3738 if (val >= (1 << NR_MOVE_TYPE))
3742 * No kind of locking is needed in here, because ->can_attach() will
3743 * check this value once in the beginning of the process, and then carry
3744 * on with stale data. This means that changes to this value will only
3745 * affect task migrations starting after the change.
3747 memcg->move_charge_at_immigrate = val;
3751 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3752 struct cftype *cft, u64 val)
3759 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3763 unsigned int lru_mask;
3766 static const struct numa_stat stats[] = {
3767 { "total", LRU_ALL },
3768 { "file", LRU_ALL_FILE },
3769 { "anon", LRU_ALL_ANON },
3770 { "unevictable", BIT(LRU_UNEVICTABLE) },
3772 const struct numa_stat *stat;
3775 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3777 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3778 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
3779 seq_printf(m, "%s=%lu", stat->name, nr);
3780 for_each_node_state(nid, N_MEMORY) {
3781 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
3783 seq_printf(m, " N%d=%lu", nid, nr);
3788 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3789 struct mem_cgroup *iter;
3792 for_each_mem_cgroup_tree(iter, memcg)
3793 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
3794 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
3795 for_each_node_state(nid, N_MEMORY) {
3797 for_each_mem_cgroup_tree(iter, memcg)
3798 nr += mem_cgroup_node_nr_lru_pages(
3799 iter, nid, stat->lru_mask);
3800 seq_printf(m, " N%d=%lu", nid, nr);
3807 #endif /* CONFIG_NUMA */
3809 static inline void mem_cgroup_lru_names_not_uptodate(void)
3811 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
3814 static int memcg_stat_show(struct seq_file *m, void *v)
3816 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3817 unsigned long memory, memsw;
3818 struct mem_cgroup *mi;
3821 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3822 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
3824 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
3825 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
3828 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
3829 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
3830 mem_cgroup_read_events(memcg, i));
3832 for (i = 0; i < NR_LRU_LISTS; i++)
3833 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
3834 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
3836 /* Hierarchical information */
3837 memory = memsw = PAGE_COUNTER_MAX;
3838 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
3839 memory = min(memory, mi->memory.limit);
3840 memsw = min(memsw, mi->memsw.limit);
3842 seq_printf(m, "hierarchical_memory_limit %llu\n",
3843 (u64)memory * PAGE_SIZE);
3844 if (do_swap_account)
3845 seq_printf(m, "hierarchical_memsw_limit %llu\n",
3846 (u64)memsw * PAGE_SIZE);
3848 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3851 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
3853 for_each_mem_cgroup_tree(mi, memcg)
3854 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
3855 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
3858 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
3859 unsigned long long val = 0;
3861 for_each_mem_cgroup_tree(mi, memcg)
3862 val += mem_cgroup_read_events(mi, i);
3863 seq_printf(m, "total_%s %llu\n",
3864 mem_cgroup_events_names[i], val);
3867 for (i = 0; i < NR_LRU_LISTS; i++) {
3868 unsigned long long val = 0;
3870 for_each_mem_cgroup_tree(mi, memcg)
3871 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
3872 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
3875 #ifdef CONFIG_DEBUG_VM
3878 struct mem_cgroup_per_zone *mz;
3879 struct zone_reclaim_stat *rstat;
3880 unsigned long recent_rotated[2] = {0, 0};
3881 unsigned long recent_scanned[2] = {0, 0};
3883 for_each_online_node(nid)
3884 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3885 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
3886 rstat = &mz->lruvec.reclaim_stat;
3888 recent_rotated[0] += rstat->recent_rotated[0];
3889 recent_rotated[1] += rstat->recent_rotated[1];
3890 recent_scanned[0] += rstat->recent_scanned[0];
3891 recent_scanned[1] += rstat->recent_scanned[1];
3893 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
3894 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
3895 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
3896 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
3903 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
3906 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3908 return mem_cgroup_swappiness(memcg);
3911 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
3912 struct cftype *cft, u64 val)
3914 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3920 memcg->swappiness = val;
3922 vm_swappiness = val;
3927 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3929 struct mem_cgroup_threshold_ary *t;
3930 unsigned long usage;
3935 t = rcu_dereference(memcg->thresholds.primary);
3937 t = rcu_dereference(memcg->memsw_thresholds.primary);
3942 usage = mem_cgroup_usage(memcg, swap);
3945 * current_threshold points to threshold just below or equal to usage.
3946 * If it's not true, a threshold was crossed after last
3947 * call of __mem_cgroup_threshold().
3949 i = t->current_threshold;
3952 * Iterate backward over array of thresholds starting from
3953 * current_threshold and check if a threshold is crossed.
3954 * If none of thresholds below usage is crossed, we read
3955 * only one element of the array here.
3957 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3958 eventfd_signal(t->entries[i].eventfd, 1);
3960 /* i = current_threshold + 1 */
3964 * Iterate forward over array of thresholds starting from
3965 * current_threshold+1 and check if a threshold is crossed.
3966 * If none of thresholds above usage is crossed, we read
3967 * only one element of the array here.
3969 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3970 eventfd_signal(t->entries[i].eventfd, 1);
3972 /* Update current_threshold */
3973 t->current_threshold = i - 1;
3978 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3981 __mem_cgroup_threshold(memcg, false);
3982 if (do_swap_account)
3983 __mem_cgroup_threshold(memcg, true);
3985 memcg = parent_mem_cgroup(memcg);
3989 static int compare_thresholds(const void *a, const void *b)
3991 const struct mem_cgroup_threshold *_a = a;
3992 const struct mem_cgroup_threshold *_b = b;
3994 if (_a->threshold > _b->threshold)
3997 if (_a->threshold < _b->threshold)
4003 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4005 struct mem_cgroup_eventfd_list *ev;
4007 spin_lock(&memcg_oom_lock);
4009 list_for_each_entry(ev, &memcg->oom_notify, list)
4010 eventfd_signal(ev->eventfd, 1);
4012 spin_unlock(&memcg_oom_lock);
4016 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4018 struct mem_cgroup *iter;
4020 for_each_mem_cgroup_tree(iter, memcg)
4021 mem_cgroup_oom_notify_cb(iter);
4024 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4025 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4027 struct mem_cgroup_thresholds *thresholds;
4028 struct mem_cgroup_threshold_ary *new;
4029 unsigned long threshold;
4030 unsigned long usage;
4033 ret = page_counter_memparse(args, &threshold);
4037 mutex_lock(&memcg->thresholds_lock);
4040 thresholds = &memcg->thresholds;
4041 usage = mem_cgroup_usage(memcg, false);
4042 } else if (type == _MEMSWAP) {
4043 thresholds = &memcg->memsw_thresholds;
4044 usage = mem_cgroup_usage(memcg, true);
4048 /* Check if a threshold crossed before adding a new one */
4049 if (thresholds->primary)
4050 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4052 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4054 /* Allocate memory for new array of thresholds */
4055 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4063 /* Copy thresholds (if any) to new array */
4064 if (thresholds->primary) {
4065 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4066 sizeof(struct mem_cgroup_threshold));
4069 /* Add new threshold */
4070 new->entries[size - 1].eventfd = eventfd;
4071 new->entries[size - 1].threshold = threshold;
4073 /* Sort thresholds. Registering of new threshold isn't time-critical */
4074 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4075 compare_thresholds, NULL);
4077 /* Find current threshold */
4078 new->current_threshold = -1;
4079 for (i = 0; i < size; i++) {
4080 if (new->entries[i].threshold <= usage) {
4082 * new->current_threshold will not be used until
4083 * rcu_assign_pointer(), so it's safe to increment
4086 ++new->current_threshold;
4091 /* Free old spare buffer and save old primary buffer as spare */
4092 kfree(thresholds->spare);
4093 thresholds->spare = thresholds->primary;
4095 rcu_assign_pointer(thresholds->primary, new);
4097 /* To be sure that nobody uses thresholds */
4101 mutex_unlock(&memcg->thresholds_lock);
4106 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4107 struct eventfd_ctx *eventfd, const char *args)
4109 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4112 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4113 struct eventfd_ctx *eventfd, const char *args)
4115 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4118 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4119 struct eventfd_ctx *eventfd, enum res_type type)
4121 struct mem_cgroup_thresholds *thresholds;
4122 struct mem_cgroup_threshold_ary *new;
4123 unsigned long usage;
4126 mutex_lock(&memcg->thresholds_lock);
4129 thresholds = &memcg->thresholds;
4130 usage = mem_cgroup_usage(memcg, false);
4131 } else if (type == _MEMSWAP) {
4132 thresholds = &memcg->memsw_thresholds;
4133 usage = mem_cgroup_usage(memcg, true);
4137 if (!thresholds->primary)
4140 /* Check if a threshold crossed before removing */
4141 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4143 /* Calculate new number of threshold */
4145 for (i = 0; i < thresholds->primary->size; i++) {
4146 if (thresholds->primary->entries[i].eventfd != eventfd)
4150 new = thresholds->spare;
4152 /* Set thresholds array to NULL if we don't have thresholds */
4161 /* Copy thresholds and find current threshold */
4162 new->current_threshold = -1;
4163 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4164 if (thresholds->primary->entries[i].eventfd == eventfd)
4167 new->entries[j] = thresholds->primary->entries[i];
4168 if (new->entries[j].threshold <= usage) {
4170 * new->current_threshold will not be used
4171 * until rcu_assign_pointer(), so it's safe to increment
4174 ++new->current_threshold;
4180 /* Swap primary and spare array */
4181 thresholds->spare = thresholds->primary;
4182 /* If all events are unregistered, free the spare array */
4184 kfree(thresholds->spare);
4185 thresholds->spare = NULL;
4188 rcu_assign_pointer(thresholds->primary, new);
4190 /* To be sure that nobody uses thresholds */
4193 mutex_unlock(&memcg->thresholds_lock);
4196 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4197 struct eventfd_ctx *eventfd)
4199 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4202 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4203 struct eventfd_ctx *eventfd)
4205 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4208 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4209 struct eventfd_ctx *eventfd, const char *args)
4211 struct mem_cgroup_eventfd_list *event;
4213 event = kmalloc(sizeof(*event), GFP_KERNEL);
4217 spin_lock(&memcg_oom_lock);
4219 event->eventfd = eventfd;
4220 list_add(&event->list, &memcg->oom_notify);
4222 /* already in OOM ? */
4223 if (atomic_read(&memcg->under_oom))
4224 eventfd_signal(eventfd, 1);
4225 spin_unlock(&memcg_oom_lock);
4230 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4231 struct eventfd_ctx *eventfd)
4233 struct mem_cgroup_eventfd_list *ev, *tmp;
4235 spin_lock(&memcg_oom_lock);
4237 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4238 if (ev->eventfd == eventfd) {
4239 list_del(&ev->list);
4244 spin_unlock(&memcg_oom_lock);
4247 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4249 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
4251 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4252 seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
4256 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4257 struct cftype *cft, u64 val)
4259 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4261 /* cannot set to root cgroup and only 0 and 1 are allowed */
4262 if (!css->parent || !((val == 0) || (val == 1)))
4265 memcg->oom_kill_disable = val;
4267 memcg_oom_recover(memcg);
4272 #ifdef CONFIG_MEMCG_KMEM
4273 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4277 memcg->kmemcg_id = -1;
4278 ret = memcg_propagate_kmem(memcg);
4282 return mem_cgroup_sockets_init(memcg, ss);
4285 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
4287 mem_cgroup_sockets_destroy(memcg);
4290 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4295 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
4301 * DO NOT USE IN NEW FILES.
4303 * "cgroup.event_control" implementation.
4305 * This is way over-engineered. It tries to support fully configurable
4306 * events for each user. Such level of flexibility is completely
4307 * unnecessary especially in the light of the planned unified hierarchy.
4309 * Please deprecate this and replace with something simpler if at all
4314 * Unregister event and free resources.
4316 * Gets called from workqueue.
4318 static void memcg_event_remove(struct work_struct *work)
4320 struct mem_cgroup_event *event =
4321 container_of(work, struct mem_cgroup_event, remove);
4322 struct mem_cgroup *memcg = event->memcg;
4324 remove_wait_queue(event->wqh, &event->wait);
4326 event->unregister_event(memcg, event->eventfd);
4328 /* Notify userspace the event is going away. */
4329 eventfd_signal(event->eventfd, 1);
4331 eventfd_ctx_put(event->eventfd);
4333 css_put(&memcg->css);
4337 * Gets called on POLLHUP on eventfd when user closes it.
4339 * Called with wqh->lock held and interrupts disabled.
4341 static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
4342 int sync, void *key)
4344 struct mem_cgroup_event *event =
4345 container_of(wait, struct mem_cgroup_event, wait);
4346 struct mem_cgroup *memcg = event->memcg;
4347 unsigned long flags = (unsigned long)key;
4349 if (flags & POLLHUP) {
4351 * If the event has been detached at cgroup removal, we
4352 * can simply return knowing the other side will cleanup
4355 * We can't race against event freeing since the other
4356 * side will require wqh->lock via remove_wait_queue(),
4359 spin_lock(&memcg->event_list_lock);
4360 if (!list_empty(&event->list)) {
4361 list_del_init(&event->list);
4363 * We are in atomic context, but cgroup_event_remove()
4364 * may sleep, so we have to call it in workqueue.
4366 schedule_work(&event->remove);
4368 spin_unlock(&memcg->event_list_lock);
4374 static void memcg_event_ptable_queue_proc(struct file *file,
4375 wait_queue_head_t *wqh, poll_table *pt)
4377 struct mem_cgroup_event *event =
4378 container_of(pt, struct mem_cgroup_event, pt);
4381 add_wait_queue(wqh, &event->wait);
4385 * DO NOT USE IN NEW FILES.
4387 * Parse input and register new cgroup event handler.
4389 * Input must be in format '<event_fd> <control_fd> <args>'.
4390 * Interpretation of args is defined by control file implementation.
4392 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4393 char *buf, size_t nbytes, loff_t off)
4395 struct cgroup_subsys_state *css = of_css(of);
4396 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4397 struct mem_cgroup_event *event;
4398 struct cgroup_subsys_state *cfile_css;
4399 unsigned int efd, cfd;
4406 buf = strstrip(buf);
4408 efd = simple_strtoul(buf, &endp, 10);
4413 cfd = simple_strtoul(buf, &endp, 10);
4414 if ((*endp != ' ') && (*endp != '\0'))
4418 event = kzalloc(sizeof(*event), GFP_KERNEL);
4422 event->memcg = memcg;
4423 INIT_LIST_HEAD(&event->list);
4424 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4425 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4426 INIT_WORK(&event->remove, memcg_event_remove);
4434 event->eventfd = eventfd_ctx_fileget(efile.file);
4435 if (IS_ERR(event->eventfd)) {
4436 ret = PTR_ERR(event->eventfd);
4443 goto out_put_eventfd;
4446 /* the process need read permission on control file */
4447 /* AV: shouldn't we check that it's been opened for read instead? */
4448 ret = inode_permission(file_inode(cfile.file), MAY_READ);
4453 * Determine the event callbacks and set them in @event. This used
4454 * to be done via struct cftype but cgroup core no longer knows
4455 * about these events. The following is crude but the whole thing
4456 * is for compatibility anyway.
4458 * DO NOT ADD NEW FILES.
4460 name = cfile.file->f_dentry->d_name.name;
4462 if (!strcmp(name, "memory.usage_in_bytes")) {
4463 event->register_event = mem_cgroup_usage_register_event;
4464 event->unregister_event = mem_cgroup_usage_unregister_event;
4465 } else if (!strcmp(name, "memory.oom_control")) {
4466 event->register_event = mem_cgroup_oom_register_event;
4467 event->unregister_event = mem_cgroup_oom_unregister_event;
4468 } else if (!strcmp(name, "memory.pressure_level")) {
4469 event->register_event = vmpressure_register_event;
4470 event->unregister_event = vmpressure_unregister_event;
4471 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4472 event->register_event = memsw_cgroup_usage_register_event;
4473 event->unregister_event = memsw_cgroup_usage_unregister_event;
4480 * Verify @cfile should belong to @css. Also, remaining events are
4481 * automatically removed on cgroup destruction but the removal is
4482 * asynchronous, so take an extra ref on @css.
4484 cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
4485 &memory_cgrp_subsys);
4487 if (IS_ERR(cfile_css))
4489 if (cfile_css != css) {
4494 ret = event->register_event(memcg, event->eventfd, buf);
4498 efile.file->f_op->poll(efile.file, &event->pt);
4500 spin_lock(&memcg->event_list_lock);
4501 list_add(&event->list, &memcg->event_list);
4502 spin_unlock(&memcg->event_list_lock);
4514 eventfd_ctx_put(event->eventfd);
4523 static struct cftype mem_cgroup_files[] = {
4525 .name = "usage_in_bytes",
4526 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4527 .read_u64 = mem_cgroup_read_u64,
4530 .name = "max_usage_in_bytes",
4531 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4532 .write = mem_cgroup_reset,
4533 .read_u64 = mem_cgroup_read_u64,
4536 .name = "limit_in_bytes",
4537 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4538 .write = mem_cgroup_write,
4539 .read_u64 = mem_cgroup_read_u64,
4542 .name = "soft_limit_in_bytes",
4543 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4544 .write = mem_cgroup_write,
4545 .read_u64 = mem_cgroup_read_u64,
4549 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4550 .write = mem_cgroup_reset,
4551 .read_u64 = mem_cgroup_read_u64,
4555 .seq_show = memcg_stat_show,
4558 .name = "force_empty",
4559 .write = mem_cgroup_force_empty_write,
4562 .name = "use_hierarchy",
4563 .write_u64 = mem_cgroup_hierarchy_write,
4564 .read_u64 = mem_cgroup_hierarchy_read,
4567 .name = "cgroup.event_control", /* XXX: for compat */
4568 .write = memcg_write_event_control,
4569 .flags = CFTYPE_NO_PREFIX,
4573 .name = "swappiness",
4574 .read_u64 = mem_cgroup_swappiness_read,
4575 .write_u64 = mem_cgroup_swappiness_write,
4578 .name = "move_charge_at_immigrate",
4579 .read_u64 = mem_cgroup_move_charge_read,
4580 .write_u64 = mem_cgroup_move_charge_write,
4583 .name = "oom_control",
4584 .seq_show = mem_cgroup_oom_control_read,
4585 .write_u64 = mem_cgroup_oom_control_write,
4586 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4589 .name = "pressure_level",
4593 .name = "numa_stat",
4594 .seq_show = memcg_numa_stat_show,
4597 #ifdef CONFIG_MEMCG_KMEM
4599 .name = "kmem.limit_in_bytes",
4600 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4601 .write = mem_cgroup_write,
4602 .read_u64 = mem_cgroup_read_u64,
4605 .name = "kmem.usage_in_bytes",
4606 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4607 .read_u64 = mem_cgroup_read_u64,
4610 .name = "kmem.failcnt",
4611 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4612 .write = mem_cgroup_reset,
4613 .read_u64 = mem_cgroup_read_u64,
4616 .name = "kmem.max_usage_in_bytes",
4617 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4618 .write = mem_cgroup_reset,
4619 .read_u64 = mem_cgroup_read_u64,
4621 #ifdef CONFIG_SLABINFO
4623 .name = "kmem.slabinfo",
4624 .seq_start = slab_start,
4625 .seq_next = slab_next,
4626 .seq_stop = slab_stop,
4627 .seq_show = memcg_slab_show,
4631 { }, /* terminate */
4634 #ifdef CONFIG_MEMCG_SWAP
4635 static struct cftype memsw_cgroup_files[] = {
4637 .name = "memsw.usage_in_bytes",
4638 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4639 .read_u64 = mem_cgroup_read_u64,
4642 .name = "memsw.max_usage_in_bytes",
4643 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4644 .write = mem_cgroup_reset,
4645 .read_u64 = mem_cgroup_read_u64,
4648 .name = "memsw.limit_in_bytes",
4649 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4650 .write = mem_cgroup_write,
4651 .read_u64 = mem_cgroup_read_u64,
4654 .name = "memsw.failcnt",
4655 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4656 .write = mem_cgroup_reset,
4657 .read_u64 = mem_cgroup_read_u64,
4659 { }, /* terminate */
4662 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4664 struct mem_cgroup_per_node *pn;
4665 struct mem_cgroup_per_zone *mz;
4666 int zone, tmp = node;
4668 * This routine is called against possible nodes.
4669 * But it's BUG to call kmalloc() against offline node.
4671 * TODO: this routine can waste much memory for nodes which will
4672 * never be onlined. It's better to use memory hotplug callback
4675 if (!node_state(node, N_NORMAL_MEMORY))
4677 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4681 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4682 mz = &pn->zoneinfo[zone];
4683 lruvec_init(&mz->lruvec);
4684 mz->usage_in_excess = 0;
4685 mz->on_tree = false;
4688 memcg->nodeinfo[node] = pn;
4692 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4694 kfree(memcg->nodeinfo[node]);
4697 static struct mem_cgroup *mem_cgroup_alloc(void)
4699 struct mem_cgroup *memcg;
4702 size = sizeof(struct mem_cgroup);
4703 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
4705 memcg = kzalloc(size, GFP_KERNEL);
4709 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4712 spin_lock_init(&memcg->pcp_counter_lock);
4721 * At destroying mem_cgroup, references from swap_cgroup can remain.
4722 * (scanning all at force_empty is too costly...)
4724 * Instead of clearing all references at force_empty, we remember
4725 * the number of reference from swap_cgroup and free mem_cgroup when
4726 * it goes down to 0.
4728 * Removal of cgroup itself succeeds regardless of refs from swap.
4731 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4735 mem_cgroup_remove_from_trees(memcg);
4738 free_mem_cgroup_per_zone_info(memcg, node);
4740 free_percpu(memcg->stat);
4743 * We need to make sure that (at least for now), the jump label
4744 * destruction code runs outside of the cgroup lock. This is because
4745 * get_online_cpus(), which is called from the static_branch update,
4746 * can't be called inside the cgroup_lock. cpusets are the ones
4747 * enforcing this dependency, so if they ever change, we might as well.
4749 * schedule_work() will guarantee this happens. Be careful if you need
4750 * to move this code around, and make sure it is outside
4753 disarm_static_keys(memcg);
4758 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4760 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
4762 if (!memcg->memory.parent)
4764 return mem_cgroup_from_counter(memcg->memory.parent, memory);
4766 EXPORT_SYMBOL(parent_mem_cgroup);
4768 static void __init mem_cgroup_soft_limit_tree_init(void)
4770 struct mem_cgroup_tree_per_node *rtpn;
4771 struct mem_cgroup_tree_per_zone *rtpz;
4772 int tmp, node, zone;
4774 for_each_node(node) {
4776 if (!node_state(node, N_NORMAL_MEMORY))
4778 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4781 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4783 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4784 rtpz = &rtpn->rb_tree_per_zone[zone];
4785 rtpz->rb_root = RB_ROOT;
4786 spin_lock_init(&rtpz->lock);
4791 static struct cgroup_subsys_state * __ref
4792 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
4794 struct mem_cgroup *memcg;
4795 long error = -ENOMEM;
4798 memcg = mem_cgroup_alloc();
4800 return ERR_PTR(error);
4803 if (alloc_mem_cgroup_per_zone_info(memcg, node))
4807 if (parent_css == NULL) {
4808 root_mem_cgroup = memcg;
4809 page_counter_init(&memcg->memory, NULL);
4810 page_counter_init(&memcg->memsw, NULL);
4811 page_counter_init(&memcg->kmem, NULL);
4814 memcg->last_scanned_node = MAX_NUMNODES;
4815 INIT_LIST_HEAD(&memcg->oom_notify);
4816 memcg->move_charge_at_immigrate = 0;
4817 mutex_init(&memcg->thresholds_lock);
4818 spin_lock_init(&memcg->move_lock);
4819 vmpressure_init(&memcg->vmpressure);
4820 INIT_LIST_HEAD(&memcg->event_list);
4821 spin_lock_init(&memcg->event_list_lock);
4826 __mem_cgroup_free(memcg);
4827 return ERR_PTR(error);
4831 mem_cgroup_css_online(struct cgroup_subsys_state *css)
4833 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4834 struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
4837 if (css->id > MEM_CGROUP_ID_MAX)
4843 mutex_lock(&memcg_create_mutex);
4845 memcg->use_hierarchy = parent->use_hierarchy;
4846 memcg->oom_kill_disable = parent->oom_kill_disable;
4847 memcg->swappiness = mem_cgroup_swappiness(parent);
4849 if (parent->use_hierarchy) {
4850 page_counter_init(&memcg->memory, &parent->memory);
4851 page_counter_init(&memcg->memsw, &parent->memsw);
4852 page_counter_init(&memcg->kmem, &parent->kmem);
4855 * No need to take a reference to the parent because cgroup
4856 * core guarantees its existence.
4859 page_counter_init(&memcg->memory, NULL);
4860 page_counter_init(&memcg->memsw, NULL);
4861 page_counter_init(&memcg->kmem, NULL);
4863 * Deeper hierachy with use_hierarchy == false doesn't make
4864 * much sense so let cgroup subsystem know about this
4865 * unfortunate state in our controller.
4867 if (parent != root_mem_cgroup)
4868 memory_cgrp_subsys.broken_hierarchy = true;
4870 mutex_unlock(&memcg_create_mutex);
4872 ret = memcg_init_kmem(memcg, &memory_cgrp_subsys);
4877 * Make sure the memcg is initialized: mem_cgroup_iter()
4878 * orders reading memcg->initialized against its callers
4879 * reading the memcg members.
4881 smp_store_release(&memcg->initialized, 1);
4886 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
4888 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4889 struct mem_cgroup_event *event, *tmp;
4892 * Unregister events and notify userspace.
4893 * Notify userspace about cgroup removing only after rmdir of cgroup
4894 * directory to avoid race between userspace and kernelspace.
4896 spin_lock(&memcg->event_list_lock);
4897 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
4898 list_del_init(&event->list);
4899 schedule_work(&event->remove);
4901 spin_unlock(&memcg->event_list_lock);
4903 memcg_unregister_all_caches(memcg);
4904 vmpressure_cleanup(&memcg->vmpressure);
4907 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
4909 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4911 memcg_destroy_kmem(memcg);
4912 __mem_cgroup_free(memcg);
4916 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4917 * @css: the target css
4919 * Reset the states of the mem_cgroup associated with @css. This is
4920 * invoked when the userland requests disabling on the default hierarchy
4921 * but the memcg is pinned through dependency. The memcg should stop
4922 * applying policies and should revert to the vanilla state as it may be
4923 * made visible again.
4925 * The current implementation only resets the essential configurations.
4926 * This needs to be expanded to cover all the visible parts.
4928 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
4930 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4932 mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX);
4933 mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX);
4934 memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX);
4935 memcg->soft_limit = 0;
4939 /* Handlers for move charge at task migration. */
4940 static int mem_cgroup_do_precharge(unsigned long count)
4944 /* Try a single bulk charge without reclaim first */
4945 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
4947 mc.precharge += count;
4950 if (ret == -EINTR) {
4951 cancel_charge(root_mem_cgroup, count);
4955 /* Try charges one by one with reclaim */
4957 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
4959 * In case of failure, any residual charges against
4960 * mc.to will be dropped by mem_cgroup_clear_mc()
4961 * later on. However, cancel any charges that are
4962 * bypassed to root right away or they'll be lost.
4965 cancel_charge(root_mem_cgroup, 1);
4975 * get_mctgt_type - get target type of moving charge
4976 * @vma: the vma the pte to be checked belongs
4977 * @addr: the address corresponding to the pte to be checked
4978 * @ptent: the pte to be checked
4979 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4982 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4983 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4984 * move charge. if @target is not NULL, the page is stored in target->page
4985 * with extra refcnt got(Callers should handle it).
4986 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4987 * target for charge migration. if @target is not NULL, the entry is stored
4990 * Called with pte lock held.
4997 enum mc_target_type {
5003 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5004 unsigned long addr, pte_t ptent)
5006 struct page *page = vm_normal_page(vma, addr, ptent);
5008 if (!page || !page_mapped(page))
5010 if (PageAnon(page)) {
5011 /* we don't move shared anon */
5014 } else if (!move_file())
5015 /* we ignore mapcount for file pages */
5017 if (!get_page_unless_zero(page))
5024 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5025 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5027 struct page *page = NULL;
5028 swp_entry_t ent = pte_to_swp_entry(ptent);
5030 if (!move_anon() || non_swap_entry(ent))
5033 * Because lookup_swap_cache() updates some statistics counter,
5034 * we call find_get_page() with swapper_space directly.
5036 page = find_get_page(swap_address_space(ent), ent.val);
5037 if (do_swap_account)
5038 entry->val = ent.val;
5043 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5044 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5050 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5051 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5053 struct page *page = NULL;
5054 struct address_space *mapping;
5057 if (!vma->vm_file) /* anonymous vma */
5062 mapping = vma->vm_file->f_mapping;
5063 if (pte_none(ptent))
5064 pgoff = linear_page_index(vma, addr);
5065 else /* pte_file(ptent) is true */
5066 pgoff = pte_to_pgoff(ptent);
5068 /* page is moved even if it's not RSS of this task(page-faulted). */
5070 /* shmem/tmpfs may report page out on swap: account for that too. */
5071 if (shmem_mapping(mapping)) {
5072 page = find_get_entry(mapping, pgoff);
5073 if (radix_tree_exceptional_entry(page)) {
5074 swp_entry_t swp = radix_to_swp_entry(page);
5075 if (do_swap_account)
5077 page = find_get_page(swap_address_space(swp), swp.val);
5080 page = find_get_page(mapping, pgoff);
5082 page = find_get_page(mapping, pgoff);
5087 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5088 unsigned long addr, pte_t ptent, union mc_target *target)
5090 struct page *page = NULL;
5091 enum mc_target_type ret = MC_TARGET_NONE;
5092 swp_entry_t ent = { .val = 0 };
5094 if (pte_present(ptent))
5095 page = mc_handle_present_pte(vma, addr, ptent);
5096 else if (is_swap_pte(ptent))
5097 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5098 else if (pte_none(ptent) || pte_file(ptent))
5099 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5101 if (!page && !ent.val)
5105 * Do only loose check w/o serialization.
5106 * mem_cgroup_move_account() checks the page is valid or
5107 * not under LRU exclusion.
5109 if (page->mem_cgroup == mc.from) {
5110 ret = MC_TARGET_PAGE;
5112 target->page = page;
5114 if (!ret || !target)
5117 /* There is a swap entry and a page doesn't exist or isn't charged */
5118 if (ent.val && !ret &&
5119 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5120 ret = MC_TARGET_SWAP;
5127 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5129 * We don't consider swapping or file mapped pages because THP does not
5130 * support them for now.
5131 * Caller should make sure that pmd_trans_huge(pmd) is true.
5133 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5134 unsigned long addr, pmd_t pmd, union mc_target *target)
5136 struct page *page = NULL;
5137 enum mc_target_type ret = MC_TARGET_NONE;
5139 page = pmd_page(pmd);
5140 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5143 if (page->mem_cgroup == mc.from) {
5144 ret = MC_TARGET_PAGE;
5147 target->page = page;
5153 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5154 unsigned long addr, pmd_t pmd, union mc_target *target)
5156 return MC_TARGET_NONE;
5160 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5161 unsigned long addr, unsigned long end,
5162 struct mm_walk *walk)
5164 struct vm_area_struct *vma = walk->private;
5168 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
5169 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5170 mc.precharge += HPAGE_PMD_NR;
5175 if (pmd_trans_unstable(pmd))
5177 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5178 for (; addr != end; pte++, addr += PAGE_SIZE)
5179 if (get_mctgt_type(vma, addr, *pte, NULL))
5180 mc.precharge++; /* increment precharge temporarily */
5181 pte_unmap_unlock(pte - 1, ptl);
5187 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5189 unsigned long precharge;
5190 struct vm_area_struct *vma;
5192 down_read(&mm->mmap_sem);
5193 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5194 struct mm_walk mem_cgroup_count_precharge_walk = {
5195 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5199 if (is_vm_hugetlb_page(vma))
5201 walk_page_range(vma->vm_start, vma->vm_end,
5202 &mem_cgroup_count_precharge_walk);
5204 up_read(&mm->mmap_sem);
5206 precharge = mc.precharge;
5212 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5214 unsigned long precharge = mem_cgroup_count_precharge(mm);
5216 VM_BUG_ON(mc.moving_task);
5217 mc.moving_task = current;
5218 return mem_cgroup_do_precharge(precharge);
5221 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5222 static void __mem_cgroup_clear_mc(void)
5224 struct mem_cgroup *from = mc.from;
5225 struct mem_cgroup *to = mc.to;
5227 /* we must uncharge all the leftover precharges from mc.to */
5229 cancel_charge(mc.to, mc.precharge);
5233 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5234 * we must uncharge here.
5236 if (mc.moved_charge) {
5237 cancel_charge(mc.from, mc.moved_charge);
5238 mc.moved_charge = 0;
5240 /* we must fixup refcnts and charges */
5241 if (mc.moved_swap) {
5242 /* uncharge swap account from the old cgroup */
5243 if (!mem_cgroup_is_root(mc.from))
5244 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5247 * we charged both to->memory and to->memsw, so we
5248 * should uncharge to->memory.
5250 if (!mem_cgroup_is_root(mc.to))
5251 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5253 css_put_many(&mc.from->css, mc.moved_swap);
5255 /* we've already done css_get(mc.to) */
5258 memcg_oom_recover(from);
5259 memcg_oom_recover(to);
5260 wake_up_all(&mc.waitq);
5263 static void mem_cgroup_clear_mc(void)
5266 * we must clear moving_task before waking up waiters at the end of
5269 mc.moving_task = NULL;
5270 __mem_cgroup_clear_mc();
5271 spin_lock(&mc.lock);
5274 spin_unlock(&mc.lock);
5277 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
5278 struct cgroup_taskset *tset)
5280 struct task_struct *p = cgroup_taskset_first(tset);
5282 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5283 unsigned long move_charge_at_immigrate;
5286 * We are now commited to this value whatever it is. Changes in this
5287 * tunable will only affect upcoming migrations, not the current one.
5288 * So we need to save it, and keep it going.
5290 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
5291 if (move_charge_at_immigrate) {
5292 struct mm_struct *mm;
5293 struct mem_cgroup *from = mem_cgroup_from_task(p);
5295 VM_BUG_ON(from == memcg);
5297 mm = get_task_mm(p);
5300 /* We move charges only when we move a owner of the mm */
5301 if (mm->owner == p) {
5304 VM_BUG_ON(mc.precharge);
5305 VM_BUG_ON(mc.moved_charge);
5306 VM_BUG_ON(mc.moved_swap);
5308 spin_lock(&mc.lock);
5311 mc.immigrate_flags = move_charge_at_immigrate;
5312 spin_unlock(&mc.lock);
5313 /* We set mc.moving_task later */
5315 ret = mem_cgroup_precharge_mc(mm);
5317 mem_cgroup_clear_mc();
5324 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
5325 struct cgroup_taskset *tset)
5328 mem_cgroup_clear_mc();
5331 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5332 unsigned long addr, unsigned long end,
5333 struct mm_walk *walk)
5336 struct vm_area_struct *vma = walk->private;
5339 enum mc_target_type target_type;
5340 union mc_target target;
5344 * We don't take compound_lock() here but no race with splitting thp
5346 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5347 * under splitting, which means there's no concurrent thp split,
5348 * - if another thread runs into split_huge_page() just after we
5349 * entered this if-block, the thread must wait for page table lock
5350 * to be unlocked in __split_huge_page_splitting(), where the main
5351 * part of thp split is not executed yet.
5353 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
5354 if (mc.precharge < HPAGE_PMD_NR) {
5358 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5359 if (target_type == MC_TARGET_PAGE) {
5361 if (!isolate_lru_page(page)) {
5362 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
5364 mc.precharge -= HPAGE_PMD_NR;
5365 mc.moved_charge += HPAGE_PMD_NR;
5367 putback_lru_page(page);
5375 if (pmd_trans_unstable(pmd))
5378 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5379 for (; addr != end; addr += PAGE_SIZE) {
5380 pte_t ptent = *(pte++);
5386 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5387 case MC_TARGET_PAGE:
5389 if (isolate_lru_page(page))
5391 if (!mem_cgroup_move_account(page, 1, mc.from, mc.to)) {
5393 /* we uncharge from mc.from later. */
5396 putback_lru_page(page);
5397 put: /* get_mctgt_type() gets the page */
5400 case MC_TARGET_SWAP:
5402 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5404 /* we fixup refcnts and charges later. */
5412 pte_unmap_unlock(pte - 1, ptl);
5417 * We have consumed all precharges we got in can_attach().
5418 * We try charge one by one, but don't do any additional
5419 * charges to mc.to if we have failed in charge once in attach()
5422 ret = mem_cgroup_do_precharge(1);
5430 static void mem_cgroup_move_charge(struct mm_struct *mm)
5432 struct vm_area_struct *vma;
5434 lru_add_drain_all();
5436 * Signal mem_cgroup_begin_page_stat() to take the memcg's
5437 * move_lock while we're moving its pages to another memcg.
5438 * Then wait for already started RCU-only updates to finish.
5440 atomic_inc(&mc.from->moving_account);
5443 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5445 * Someone who are holding the mmap_sem might be waiting in
5446 * waitq. So we cancel all extra charges, wake up all waiters,
5447 * and retry. Because we cancel precharges, we might not be able
5448 * to move enough charges, but moving charge is a best-effort
5449 * feature anyway, so it wouldn't be a big problem.
5451 __mem_cgroup_clear_mc();
5455 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5457 struct mm_walk mem_cgroup_move_charge_walk = {
5458 .pmd_entry = mem_cgroup_move_charge_pte_range,
5462 if (is_vm_hugetlb_page(vma))
5464 ret = walk_page_range(vma->vm_start, vma->vm_end,
5465 &mem_cgroup_move_charge_walk);
5468 * means we have consumed all precharges and failed in
5469 * doing additional charge. Just abandon here.
5473 up_read(&mm->mmap_sem);
5474 atomic_dec(&mc.from->moving_account);
5477 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
5478 struct cgroup_taskset *tset)
5480 struct task_struct *p = cgroup_taskset_first(tset);
5481 struct mm_struct *mm = get_task_mm(p);
5485 mem_cgroup_move_charge(mm);
5489 mem_cgroup_clear_mc();
5491 #else /* !CONFIG_MMU */
5492 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
5493 struct cgroup_taskset *tset)
5497 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
5498 struct cgroup_taskset *tset)
5501 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
5502 struct cgroup_taskset *tset)
5508 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5509 * to verify whether we're attached to the default hierarchy on each mount
5512 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
5515 * use_hierarchy is forced on the default hierarchy. cgroup core
5516 * guarantees that @root doesn't have any children, so turning it
5517 * on for the root memcg is enough.
5519 if (cgroup_on_dfl(root_css->cgroup))
5520 mem_cgroup_from_css(root_css)->use_hierarchy = true;
5523 struct cgroup_subsys memory_cgrp_subsys = {
5524 .css_alloc = mem_cgroup_css_alloc,
5525 .css_online = mem_cgroup_css_online,
5526 .css_offline = mem_cgroup_css_offline,
5527 .css_free = mem_cgroup_css_free,
5528 .css_reset = mem_cgroup_css_reset,
5529 .can_attach = mem_cgroup_can_attach,
5530 .cancel_attach = mem_cgroup_cancel_attach,
5531 .attach = mem_cgroup_move_task,
5532 .bind = mem_cgroup_bind,
5533 .legacy_cftypes = mem_cgroup_files,
5537 #ifdef CONFIG_MEMCG_SWAP
5538 static int __init enable_swap_account(char *s)
5540 if (!strcmp(s, "1"))
5541 really_do_swap_account = 1;
5542 else if (!strcmp(s, "0"))
5543 really_do_swap_account = 0;
5546 __setup("swapaccount=", enable_swap_account);
5548 static void __init memsw_file_init(void)
5550 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
5551 memsw_cgroup_files));
5554 static void __init enable_swap_cgroup(void)
5556 if (!mem_cgroup_disabled() && really_do_swap_account) {
5557 do_swap_account = 1;
5563 static void __init enable_swap_cgroup(void)
5568 #ifdef CONFIG_MEMCG_SWAP
5570 * mem_cgroup_swapout - transfer a memsw charge to swap
5571 * @page: page whose memsw charge to transfer
5572 * @entry: swap entry to move the charge to
5574 * Transfer the memsw charge of @page to @entry.
5576 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
5578 struct mem_cgroup *memcg;
5579 unsigned short oldid;
5581 VM_BUG_ON_PAGE(PageLRU(page), page);
5582 VM_BUG_ON_PAGE(page_count(page), page);
5584 if (!do_swap_account)
5587 memcg = page->mem_cgroup;
5589 /* Readahead page, never charged */
5593 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
5594 VM_BUG_ON_PAGE(oldid, page);
5595 mem_cgroup_swap_statistics(memcg, true);
5597 page->mem_cgroup = NULL;
5599 if (!mem_cgroup_is_root(memcg))
5600 page_counter_uncharge(&memcg->memory, 1);
5602 /* XXX: caller holds IRQ-safe mapping->tree_lock */
5603 VM_BUG_ON(!irqs_disabled());
5605 mem_cgroup_charge_statistics(memcg, page, -1);
5606 memcg_check_events(memcg, page);
5610 * mem_cgroup_uncharge_swap - uncharge a swap entry
5611 * @entry: swap entry to uncharge
5613 * Drop the memsw charge associated with @entry.
5615 void mem_cgroup_uncharge_swap(swp_entry_t entry)
5617 struct mem_cgroup *memcg;
5620 if (!do_swap_account)
5623 id = swap_cgroup_record(entry, 0);
5625 memcg = mem_cgroup_lookup(id);
5627 if (!mem_cgroup_is_root(memcg))
5628 page_counter_uncharge(&memcg->memsw, 1);
5629 mem_cgroup_swap_statistics(memcg, false);
5630 css_put(&memcg->css);
5637 * mem_cgroup_try_charge - try charging a page
5638 * @page: page to charge
5639 * @mm: mm context of the victim
5640 * @gfp_mask: reclaim mode
5641 * @memcgp: charged memcg return
5643 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5644 * pages according to @gfp_mask if necessary.
5646 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5647 * Otherwise, an error code is returned.
5649 * After page->mapping has been set up, the caller must finalize the
5650 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5651 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5653 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
5654 gfp_t gfp_mask, struct mem_cgroup **memcgp)
5656 struct mem_cgroup *memcg = NULL;
5657 unsigned int nr_pages = 1;
5660 if (mem_cgroup_disabled())
5663 if (PageSwapCache(page)) {
5665 * Every swap fault against a single page tries to charge the
5666 * page, bail as early as possible. shmem_unuse() encounters
5667 * already charged pages, too. The USED bit is protected by
5668 * the page lock, which serializes swap cache removal, which
5669 * in turn serializes uncharging.
5671 if (page->mem_cgroup)
5675 if (PageTransHuge(page)) {
5676 nr_pages <<= compound_order(page);
5677 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5680 if (do_swap_account && PageSwapCache(page))
5681 memcg = try_get_mem_cgroup_from_page(page);
5683 memcg = get_mem_cgroup_from_mm(mm);
5685 ret = try_charge(memcg, gfp_mask, nr_pages);
5687 css_put(&memcg->css);
5689 if (ret == -EINTR) {
5690 memcg = root_mem_cgroup;
5699 * mem_cgroup_commit_charge - commit a page charge
5700 * @page: page to charge
5701 * @memcg: memcg to charge the page to
5702 * @lrucare: page might be on LRU already
5704 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5705 * after page->mapping has been set up. This must happen atomically
5706 * as part of the page instantiation, i.e. under the page table lock
5707 * for anonymous pages, under the page lock for page and swap cache.
5709 * In addition, the page must not be on the LRU during the commit, to
5710 * prevent racing with task migration. If it might be, use @lrucare.
5712 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5714 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
5717 unsigned int nr_pages = 1;
5719 VM_BUG_ON_PAGE(!page->mapping, page);
5720 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
5722 if (mem_cgroup_disabled())
5725 * Swap faults will attempt to charge the same page multiple
5726 * times. But reuse_swap_page() might have removed the page
5727 * from swapcache already, so we can't check PageSwapCache().
5732 commit_charge(page, memcg, lrucare);
5734 if (PageTransHuge(page)) {
5735 nr_pages <<= compound_order(page);
5736 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5739 local_irq_disable();
5740 mem_cgroup_charge_statistics(memcg, page, nr_pages);
5741 memcg_check_events(memcg, page);
5744 if (do_swap_account && PageSwapCache(page)) {
5745 swp_entry_t entry = { .val = page_private(page) };
5747 * The swap entry might not get freed for a long time,
5748 * let's not wait for it. The page already received a
5749 * memory+swap charge, drop the swap entry duplicate.
5751 mem_cgroup_uncharge_swap(entry);
5756 * mem_cgroup_cancel_charge - cancel a page charge
5757 * @page: page to charge
5758 * @memcg: memcg to charge the page to
5760 * Cancel a charge transaction started by mem_cgroup_try_charge().
5762 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
5764 unsigned int nr_pages = 1;
5766 if (mem_cgroup_disabled())
5769 * Swap faults will attempt to charge the same page multiple
5770 * times. But reuse_swap_page() might have removed the page
5771 * from swapcache already, so we can't check PageSwapCache().
5776 if (PageTransHuge(page)) {
5777 nr_pages <<= compound_order(page);
5778 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5781 cancel_charge(memcg, nr_pages);
5784 static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
5785 unsigned long nr_anon, unsigned long nr_file,
5786 unsigned long nr_huge, struct page *dummy_page)
5788 unsigned long nr_pages = nr_anon + nr_file;
5789 unsigned long flags;
5791 if (!mem_cgroup_is_root(memcg)) {
5792 page_counter_uncharge(&memcg->memory, nr_pages);
5793 if (do_swap_account)
5794 page_counter_uncharge(&memcg->memsw, nr_pages);
5795 memcg_oom_recover(memcg);
5798 local_irq_save(flags);
5799 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
5800 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
5801 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
5802 __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
5803 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
5804 memcg_check_events(memcg, dummy_page);
5805 local_irq_restore(flags);
5807 if (!mem_cgroup_is_root(memcg))
5808 css_put_many(&memcg->css, nr_pages);
5811 static void uncharge_list(struct list_head *page_list)
5813 struct mem_cgroup *memcg = NULL;
5814 unsigned long nr_anon = 0;
5815 unsigned long nr_file = 0;
5816 unsigned long nr_huge = 0;
5817 unsigned long pgpgout = 0;
5818 struct list_head *next;
5821 next = page_list->next;
5823 unsigned int nr_pages = 1;
5825 page = list_entry(next, struct page, lru);
5826 next = page->lru.next;
5828 VM_BUG_ON_PAGE(PageLRU(page), page);
5829 VM_BUG_ON_PAGE(page_count(page), page);
5831 if (!page->mem_cgroup)
5835 * Nobody should be changing or seriously looking at
5836 * page->mem_cgroup at this point, we have fully
5837 * exclusive access to the page.
5840 if (memcg != page->mem_cgroup) {
5842 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5844 pgpgout = nr_anon = nr_file = nr_huge = 0;
5846 memcg = page->mem_cgroup;
5849 if (PageTransHuge(page)) {
5850 nr_pages <<= compound_order(page);
5851 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5852 nr_huge += nr_pages;
5856 nr_anon += nr_pages;
5858 nr_file += nr_pages;
5860 page->mem_cgroup = NULL;
5863 } while (next != page_list);
5866 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5871 * mem_cgroup_uncharge - uncharge a page
5872 * @page: page to uncharge
5874 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5875 * mem_cgroup_commit_charge().
5877 void mem_cgroup_uncharge(struct page *page)
5879 if (mem_cgroup_disabled())
5882 /* Don't touch page->lru of any random page, pre-check: */
5883 if (!page->mem_cgroup)
5886 INIT_LIST_HEAD(&page->lru);
5887 uncharge_list(&page->lru);
5891 * mem_cgroup_uncharge_list - uncharge a list of page
5892 * @page_list: list of pages to uncharge
5894 * Uncharge a list of pages previously charged with
5895 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5897 void mem_cgroup_uncharge_list(struct list_head *page_list)
5899 if (mem_cgroup_disabled())
5902 if (!list_empty(page_list))
5903 uncharge_list(page_list);
5907 * mem_cgroup_migrate - migrate a charge to another page
5908 * @oldpage: currently charged page
5909 * @newpage: page to transfer the charge to
5910 * @lrucare: both pages might be on the LRU already
5912 * Migrate the charge from @oldpage to @newpage.
5914 * Both pages must be locked, @newpage->mapping must be set up.
5916 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
5919 struct mem_cgroup *memcg;
5922 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
5923 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
5924 VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
5925 VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
5926 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
5927 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
5930 if (mem_cgroup_disabled())
5933 /* Page cache replacement: new page already charged? */
5934 if (newpage->mem_cgroup)
5938 * Swapcache readahead pages can get migrated before being
5939 * charged, and migration from compaction can happen to an
5940 * uncharged page when the PFN walker finds a page that
5941 * reclaim just put back on the LRU but has not released yet.
5943 memcg = oldpage->mem_cgroup;
5948 lock_page_lru(oldpage, &isolated);
5950 oldpage->mem_cgroup = NULL;
5953 unlock_page_lru(oldpage, isolated);
5955 commit_charge(newpage, memcg, lrucare);
5959 * subsys_initcall() for memory controller.
5961 * Some parts like hotcpu_notifier() have to be initialized from this context
5962 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
5963 * everything that doesn't depend on a specific mem_cgroup structure should
5964 * be initialized from here.
5966 static int __init mem_cgroup_init(void)
5968 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
5969 enable_swap_cgroup();
5970 mem_cgroup_soft_limit_tree_init();
5974 subsys_initcall(mem_cgroup_init);