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 page_cgroup *pc;
1278 struct lruvec *lruvec;
1280 if (mem_cgroup_disabled()) {
1281 lruvec = &zone->lruvec;
1285 pc = lookup_page_cgroup(page);
1286 memcg = pc->mem_cgroup;
1288 * Swapcache readahead pages are added to the LRU - and
1289 * possibly migrated - before they are charged.
1292 memcg = root_mem_cgroup;
1294 mz = mem_cgroup_page_zoneinfo(memcg, page);
1295 lruvec = &mz->lruvec;
1298 * Since a node can be onlined after the mem_cgroup was created,
1299 * we have to be prepared to initialize lruvec->zone here;
1300 * and if offlined then reonlined, we need to reinitialize it.
1302 if (unlikely(lruvec->zone != zone))
1303 lruvec->zone = zone;
1308 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1309 * @lruvec: mem_cgroup per zone lru vector
1310 * @lru: index of lru list the page is sitting on
1311 * @nr_pages: positive when adding or negative when removing
1313 * This function must be called when a page is added to or removed from an
1316 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1319 struct mem_cgroup_per_zone *mz;
1320 unsigned long *lru_size;
1322 if (mem_cgroup_disabled())
1325 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1326 lru_size = mz->lru_size + lru;
1327 *lru_size += nr_pages;
1328 VM_BUG_ON((long)(*lru_size) < 0);
1331 bool mem_cgroup_is_descendant(struct mem_cgroup *memcg, struct mem_cgroup *root)
1335 if (!root->use_hierarchy)
1337 return cgroup_is_descendant(memcg->css.cgroup, root->css.cgroup);
1340 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
1342 struct mem_cgroup *task_memcg;
1343 struct task_struct *p;
1346 p = find_lock_task_mm(task);
1348 task_memcg = get_mem_cgroup_from_mm(p->mm);
1352 * All threads may have already detached their mm's, but the oom
1353 * killer still needs to detect if they have already been oom
1354 * killed to prevent needlessly killing additional tasks.
1357 task_memcg = mem_cgroup_from_task(task);
1358 css_get(&task_memcg->css);
1361 ret = mem_cgroup_is_descendant(task_memcg, memcg);
1362 css_put(&task_memcg->css);
1366 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1368 unsigned long inactive_ratio;
1369 unsigned long inactive;
1370 unsigned long active;
1373 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1374 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1376 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1378 inactive_ratio = int_sqrt(10 * gb);
1382 return inactive * inactive_ratio < active;
1385 #define mem_cgroup_from_counter(counter, member) \
1386 container_of(counter, struct mem_cgroup, member)
1389 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1390 * @memcg: the memory cgroup
1392 * Returns the maximum amount of memory @mem can be charged with, in
1395 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1397 unsigned long margin = 0;
1398 unsigned long count;
1399 unsigned long limit;
1401 count = page_counter_read(&memcg->memory);
1402 limit = ACCESS_ONCE(memcg->memory.limit);
1404 margin = limit - count;
1406 if (do_swap_account) {
1407 count = page_counter_read(&memcg->memsw);
1408 limit = ACCESS_ONCE(memcg->memsw.limit);
1410 margin = min(margin, limit - count);
1416 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1419 if (mem_cgroup_disabled() || !memcg->css.parent)
1420 return vm_swappiness;
1422 return memcg->swappiness;
1426 * A routine for checking "mem" is under move_account() or not.
1428 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1429 * moving cgroups. This is for waiting at high-memory pressure
1432 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1434 struct mem_cgroup *from;
1435 struct mem_cgroup *to;
1438 * Unlike task_move routines, we access mc.to, mc.from not under
1439 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1441 spin_lock(&mc.lock);
1447 ret = mem_cgroup_is_descendant(from, memcg) ||
1448 mem_cgroup_is_descendant(to, memcg);
1450 spin_unlock(&mc.lock);
1454 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1456 if (mc.moving_task && current != mc.moving_task) {
1457 if (mem_cgroup_under_move(memcg)) {
1459 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1460 /* moving charge context might have finished. */
1463 finish_wait(&mc.waitq, &wait);
1470 #define K(x) ((x) << (PAGE_SHIFT-10))
1472 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1473 * @memcg: The memory cgroup that went over limit
1474 * @p: Task that is going to be killed
1476 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1479 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1481 /* oom_info_lock ensures that parallel ooms do not interleave */
1482 static DEFINE_MUTEX(oom_info_lock);
1483 struct mem_cgroup *iter;
1489 mutex_lock(&oom_info_lock);
1492 pr_info("Task in ");
1493 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1494 pr_info(" killed as a result of limit of ");
1495 pr_cont_cgroup_path(memcg->css.cgroup);
1500 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1501 K((u64)page_counter_read(&memcg->memory)),
1502 K((u64)memcg->memory.limit), memcg->memory.failcnt);
1503 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1504 K((u64)page_counter_read(&memcg->memsw)),
1505 K((u64)memcg->memsw.limit), memcg->memsw.failcnt);
1506 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1507 K((u64)page_counter_read(&memcg->kmem)),
1508 K((u64)memcg->kmem.limit), memcg->kmem.failcnt);
1510 for_each_mem_cgroup_tree(iter, memcg) {
1511 pr_info("Memory cgroup stats for ");
1512 pr_cont_cgroup_path(iter->css.cgroup);
1515 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1516 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1518 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1519 K(mem_cgroup_read_stat(iter, i)));
1522 for (i = 0; i < NR_LRU_LISTS; i++)
1523 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1524 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1528 mutex_unlock(&oom_info_lock);
1532 * This function returns the number of memcg under hierarchy tree. Returns
1533 * 1(self count) if no children.
1535 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1538 struct mem_cgroup *iter;
1540 for_each_mem_cgroup_tree(iter, memcg)
1546 * Return the memory (and swap, if configured) limit for a memcg.
1548 static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
1550 unsigned long limit;
1552 limit = memcg->memory.limit;
1553 if (mem_cgroup_swappiness(memcg)) {
1554 unsigned long memsw_limit;
1556 memsw_limit = memcg->memsw.limit;
1557 limit = min(limit + total_swap_pages, memsw_limit);
1562 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1565 struct mem_cgroup *iter;
1566 unsigned long chosen_points = 0;
1567 unsigned long totalpages;
1568 unsigned int points = 0;
1569 struct task_struct *chosen = NULL;
1572 * If current has a pending SIGKILL or is exiting, then automatically
1573 * select it. The goal is to allow it to allocate so that it may
1574 * quickly exit and free its memory.
1576 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1577 set_thread_flag(TIF_MEMDIE);
1581 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1582 totalpages = mem_cgroup_get_limit(memcg) ? : 1;
1583 for_each_mem_cgroup_tree(iter, memcg) {
1584 struct css_task_iter it;
1585 struct task_struct *task;
1587 css_task_iter_start(&iter->css, &it);
1588 while ((task = css_task_iter_next(&it))) {
1589 switch (oom_scan_process_thread(task, totalpages, NULL,
1591 case OOM_SCAN_SELECT:
1593 put_task_struct(chosen);
1595 chosen_points = ULONG_MAX;
1596 get_task_struct(chosen);
1598 case OOM_SCAN_CONTINUE:
1600 case OOM_SCAN_ABORT:
1601 css_task_iter_end(&it);
1602 mem_cgroup_iter_break(memcg, iter);
1604 put_task_struct(chosen);
1609 points = oom_badness(task, memcg, NULL, totalpages);
1610 if (!points || points < chosen_points)
1612 /* Prefer thread group leaders for display purposes */
1613 if (points == chosen_points &&
1614 thread_group_leader(chosen))
1618 put_task_struct(chosen);
1620 chosen_points = points;
1621 get_task_struct(chosen);
1623 css_task_iter_end(&it);
1628 points = chosen_points * 1000 / totalpages;
1629 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1630 NULL, "Memory cgroup out of memory");
1634 * test_mem_cgroup_node_reclaimable
1635 * @memcg: the target memcg
1636 * @nid: the node ID to be checked.
1637 * @noswap : specify true here if the user wants flle only information.
1639 * This function returns whether the specified memcg contains any
1640 * reclaimable pages on a node. Returns true if there are any reclaimable
1641 * pages in the node.
1643 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1644 int nid, bool noswap)
1646 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1648 if (noswap || !total_swap_pages)
1650 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1655 #if MAX_NUMNODES > 1
1658 * Always updating the nodemask is not very good - even if we have an empty
1659 * list or the wrong list here, we can start from some node and traverse all
1660 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1663 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1667 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1668 * pagein/pageout changes since the last update.
1670 if (!atomic_read(&memcg->numainfo_events))
1672 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1675 /* make a nodemask where this memcg uses memory from */
1676 memcg->scan_nodes = node_states[N_MEMORY];
1678 for_each_node_mask(nid, node_states[N_MEMORY]) {
1680 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1681 node_clear(nid, memcg->scan_nodes);
1684 atomic_set(&memcg->numainfo_events, 0);
1685 atomic_set(&memcg->numainfo_updating, 0);
1689 * Selecting a node where we start reclaim from. Because what we need is just
1690 * reducing usage counter, start from anywhere is O,K. Considering
1691 * memory reclaim from current node, there are pros. and cons.
1693 * Freeing memory from current node means freeing memory from a node which
1694 * we'll use or we've used. So, it may make LRU bad. And if several threads
1695 * hit limits, it will see a contention on a node. But freeing from remote
1696 * node means more costs for memory reclaim because of memory latency.
1698 * Now, we use round-robin. Better algorithm is welcomed.
1700 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1704 mem_cgroup_may_update_nodemask(memcg);
1705 node = memcg->last_scanned_node;
1707 node = next_node(node, memcg->scan_nodes);
1708 if (node == MAX_NUMNODES)
1709 node = first_node(memcg->scan_nodes);
1711 * We call this when we hit limit, not when pages are added to LRU.
1712 * No LRU may hold pages because all pages are UNEVICTABLE or
1713 * memcg is too small and all pages are not on LRU. In that case,
1714 * we use curret node.
1716 if (unlikely(node == MAX_NUMNODES))
1717 node = numa_node_id();
1719 memcg->last_scanned_node = node;
1723 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1729 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1732 unsigned long *total_scanned)
1734 struct mem_cgroup *victim = NULL;
1737 unsigned long excess;
1738 unsigned long nr_scanned;
1739 struct mem_cgroup_reclaim_cookie reclaim = {
1744 excess = soft_limit_excess(root_memcg);
1747 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1752 * If we have not been able to reclaim
1753 * anything, it might because there are
1754 * no reclaimable pages under this hierarchy
1759 * We want to do more targeted reclaim.
1760 * excess >> 2 is not to excessive so as to
1761 * reclaim too much, nor too less that we keep
1762 * coming back to reclaim from this cgroup
1764 if (total >= (excess >> 2) ||
1765 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1770 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
1772 *total_scanned += nr_scanned;
1773 if (!soft_limit_excess(root_memcg))
1776 mem_cgroup_iter_break(root_memcg, victim);
1780 #ifdef CONFIG_LOCKDEP
1781 static struct lockdep_map memcg_oom_lock_dep_map = {
1782 .name = "memcg_oom_lock",
1786 static DEFINE_SPINLOCK(memcg_oom_lock);
1789 * Check OOM-Killer is already running under our hierarchy.
1790 * If someone is running, return false.
1792 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1794 struct mem_cgroup *iter, *failed = NULL;
1796 spin_lock(&memcg_oom_lock);
1798 for_each_mem_cgroup_tree(iter, memcg) {
1799 if (iter->oom_lock) {
1801 * this subtree of our hierarchy is already locked
1802 * so we cannot give a lock.
1805 mem_cgroup_iter_break(memcg, iter);
1808 iter->oom_lock = true;
1813 * OK, we failed to lock the whole subtree so we have
1814 * to clean up what we set up to the failing subtree
1816 for_each_mem_cgroup_tree(iter, memcg) {
1817 if (iter == failed) {
1818 mem_cgroup_iter_break(memcg, iter);
1821 iter->oom_lock = false;
1824 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1826 spin_unlock(&memcg_oom_lock);
1831 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1833 struct mem_cgroup *iter;
1835 spin_lock(&memcg_oom_lock);
1836 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
1837 for_each_mem_cgroup_tree(iter, memcg)
1838 iter->oom_lock = false;
1839 spin_unlock(&memcg_oom_lock);
1842 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1844 struct mem_cgroup *iter;
1846 for_each_mem_cgroup_tree(iter, memcg)
1847 atomic_inc(&iter->under_oom);
1850 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1852 struct mem_cgroup *iter;
1855 * When a new child is created while the hierarchy is under oom,
1856 * mem_cgroup_oom_lock() may not be called. We have to use
1857 * atomic_add_unless() here.
1859 for_each_mem_cgroup_tree(iter, memcg)
1860 atomic_add_unless(&iter->under_oom, -1, 0);
1863 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1865 struct oom_wait_info {
1866 struct mem_cgroup *memcg;
1870 static int memcg_oom_wake_function(wait_queue_t *wait,
1871 unsigned mode, int sync, void *arg)
1873 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1874 struct mem_cgroup *oom_wait_memcg;
1875 struct oom_wait_info *oom_wait_info;
1877 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1878 oom_wait_memcg = oom_wait_info->memcg;
1880 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1881 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1883 return autoremove_wake_function(wait, mode, sync, arg);
1886 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1888 atomic_inc(&memcg->oom_wakeups);
1889 /* for filtering, pass "memcg" as argument. */
1890 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1893 static void memcg_oom_recover(struct mem_cgroup *memcg)
1895 if (memcg && atomic_read(&memcg->under_oom))
1896 memcg_wakeup_oom(memcg);
1899 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1901 if (!current->memcg_oom.may_oom)
1904 * We are in the middle of the charge context here, so we
1905 * don't want to block when potentially sitting on a callstack
1906 * that holds all kinds of filesystem and mm locks.
1908 * Also, the caller may handle a failed allocation gracefully
1909 * (like optional page cache readahead) and so an OOM killer
1910 * invocation might not even be necessary.
1912 * That's why we don't do anything here except remember the
1913 * OOM context and then deal with it at the end of the page
1914 * fault when the stack is unwound, the locks are released,
1915 * and when we know whether the fault was overall successful.
1917 css_get(&memcg->css);
1918 current->memcg_oom.memcg = memcg;
1919 current->memcg_oom.gfp_mask = mask;
1920 current->memcg_oom.order = order;
1924 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1925 * @handle: actually kill/wait or just clean up the OOM state
1927 * This has to be called at the end of a page fault if the memcg OOM
1928 * handler was enabled.
1930 * Memcg supports userspace OOM handling where failed allocations must
1931 * sleep on a waitqueue until the userspace task resolves the
1932 * situation. Sleeping directly in the charge context with all kinds
1933 * of locks held is not a good idea, instead we remember an OOM state
1934 * in the task and mem_cgroup_oom_synchronize() has to be called at
1935 * the end of the page fault to complete the OOM handling.
1937 * Returns %true if an ongoing memcg OOM situation was detected and
1938 * completed, %false otherwise.
1940 bool mem_cgroup_oom_synchronize(bool handle)
1942 struct mem_cgroup *memcg = current->memcg_oom.memcg;
1943 struct oom_wait_info owait;
1946 /* OOM is global, do not handle */
1953 owait.memcg = memcg;
1954 owait.wait.flags = 0;
1955 owait.wait.func = memcg_oom_wake_function;
1956 owait.wait.private = current;
1957 INIT_LIST_HEAD(&owait.wait.task_list);
1959 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1960 mem_cgroup_mark_under_oom(memcg);
1962 locked = mem_cgroup_oom_trylock(memcg);
1965 mem_cgroup_oom_notify(memcg);
1967 if (locked && !memcg->oom_kill_disable) {
1968 mem_cgroup_unmark_under_oom(memcg);
1969 finish_wait(&memcg_oom_waitq, &owait.wait);
1970 mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
1971 current->memcg_oom.order);
1974 mem_cgroup_unmark_under_oom(memcg);
1975 finish_wait(&memcg_oom_waitq, &owait.wait);
1979 mem_cgroup_oom_unlock(memcg);
1981 * There is no guarantee that an OOM-lock contender
1982 * sees the wakeups triggered by the OOM kill
1983 * uncharges. Wake any sleepers explicitely.
1985 memcg_oom_recover(memcg);
1988 current->memcg_oom.memcg = NULL;
1989 css_put(&memcg->css);
1994 * mem_cgroup_begin_page_stat - begin a page state statistics transaction
1995 * @page: page that is going to change accounted state
1996 * @locked: &memcg->move_lock slowpath was taken
1997 * @flags: IRQ-state flags for &memcg->move_lock
1999 * This function must mark the beginning of an accounted page state
2000 * change to prevent double accounting when the page is concurrently
2001 * being moved to another memcg:
2003 * memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
2004 * if (TestClearPageState(page))
2005 * mem_cgroup_update_page_stat(memcg, state, -1);
2006 * mem_cgroup_end_page_stat(memcg, locked, flags);
2008 * The RCU lock is held throughout the transaction. The fast path can
2009 * get away without acquiring the memcg->move_lock (@locked is false)
2010 * because page moving starts with an RCU grace period.
2012 * The RCU lock also protects the memcg from being freed when the page
2013 * state that is going to change is the only thing preventing the page
2014 * from being uncharged. E.g. end-writeback clearing PageWriteback(),
2015 * which allows migration to go ahead and uncharge the page before the
2016 * account transaction might be complete.
2018 struct mem_cgroup *mem_cgroup_begin_page_stat(struct page *page,
2020 unsigned long *flags)
2022 struct mem_cgroup *memcg;
2023 struct page_cgroup *pc;
2027 if (mem_cgroup_disabled())
2030 pc = lookup_page_cgroup(page);
2032 memcg = pc->mem_cgroup;
2033 if (unlikely(!memcg))
2037 if (atomic_read(&memcg->moving_account) <= 0)
2040 spin_lock_irqsave(&memcg->move_lock, *flags);
2041 if (memcg != pc->mem_cgroup) {
2042 spin_unlock_irqrestore(&memcg->move_lock, *flags);
2051 * mem_cgroup_end_page_stat - finish a page state statistics transaction
2052 * @memcg: the memcg that was accounted against
2053 * @locked: value received from mem_cgroup_begin_page_stat()
2054 * @flags: value received from mem_cgroup_begin_page_stat()
2056 void mem_cgroup_end_page_stat(struct mem_cgroup *memcg, bool locked,
2057 unsigned long flags)
2059 if (memcg && locked)
2060 spin_unlock_irqrestore(&memcg->move_lock, flags);
2066 * mem_cgroup_update_page_stat - update page state statistics
2067 * @memcg: memcg to account against
2068 * @idx: page state item to account
2069 * @val: number of pages (positive or negative)
2071 * See mem_cgroup_begin_page_stat() for locking requirements.
2073 void mem_cgroup_update_page_stat(struct mem_cgroup *memcg,
2074 enum mem_cgroup_stat_index idx, int val)
2076 VM_BUG_ON(!rcu_read_lock_held());
2079 this_cpu_add(memcg->stat->count[idx], val);
2083 * size of first charge trial. "32" comes from vmscan.c's magic value.
2084 * TODO: maybe necessary to use big numbers in big irons.
2086 #define CHARGE_BATCH 32U
2087 struct memcg_stock_pcp {
2088 struct mem_cgroup *cached; /* this never be root cgroup */
2089 unsigned int nr_pages;
2090 struct work_struct work;
2091 unsigned long flags;
2092 #define FLUSHING_CACHED_CHARGE 0
2094 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2095 static DEFINE_MUTEX(percpu_charge_mutex);
2098 * consume_stock: Try to consume stocked charge on this cpu.
2099 * @memcg: memcg to consume from.
2100 * @nr_pages: how many pages to charge.
2102 * The charges will only happen if @memcg matches the current cpu's memcg
2103 * stock, and at least @nr_pages are available in that stock. Failure to
2104 * service an allocation will refill the stock.
2106 * returns true if successful, false otherwise.
2108 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2110 struct memcg_stock_pcp *stock;
2113 if (nr_pages > CHARGE_BATCH)
2116 stock = &get_cpu_var(memcg_stock);
2117 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
2118 stock->nr_pages -= nr_pages;
2121 put_cpu_var(memcg_stock);
2126 * Returns stocks cached in percpu and reset cached information.
2128 static void drain_stock(struct memcg_stock_pcp *stock)
2130 struct mem_cgroup *old = stock->cached;
2132 if (stock->nr_pages) {
2133 page_counter_uncharge(&old->memory, stock->nr_pages);
2134 if (do_swap_account)
2135 page_counter_uncharge(&old->memsw, stock->nr_pages);
2136 css_put_many(&old->css, stock->nr_pages);
2137 stock->nr_pages = 0;
2139 stock->cached = NULL;
2143 * This must be called under preempt disabled or must be called by
2144 * a thread which is pinned to local cpu.
2146 static void drain_local_stock(struct work_struct *dummy)
2148 struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
2150 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2153 static void __init memcg_stock_init(void)
2157 for_each_possible_cpu(cpu) {
2158 struct memcg_stock_pcp *stock =
2159 &per_cpu(memcg_stock, cpu);
2160 INIT_WORK(&stock->work, drain_local_stock);
2165 * Cache charges(val) to local per_cpu area.
2166 * This will be consumed by consume_stock() function, later.
2168 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2170 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2172 if (stock->cached != memcg) { /* reset if necessary */
2174 stock->cached = memcg;
2176 stock->nr_pages += nr_pages;
2177 put_cpu_var(memcg_stock);
2181 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2182 * of the hierarchy under it.
2184 static void drain_all_stock(struct mem_cgroup *root_memcg)
2188 /* If someone's already draining, avoid adding running more workers. */
2189 if (!mutex_trylock(&percpu_charge_mutex))
2191 /* Notify other cpus that system-wide "drain" is running */
2194 for_each_online_cpu(cpu) {
2195 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2196 struct mem_cgroup *memcg;
2198 memcg = stock->cached;
2199 if (!memcg || !stock->nr_pages)
2201 if (!mem_cgroup_is_descendant(memcg, root_memcg))
2203 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2205 drain_local_stock(&stock->work);
2207 schedule_work_on(cpu, &stock->work);
2212 mutex_unlock(&percpu_charge_mutex);
2216 * This function drains percpu counter value from DEAD cpu and
2217 * move it to local cpu. Note that this function can be preempted.
2219 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2223 spin_lock(&memcg->pcp_counter_lock);
2224 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2225 long x = per_cpu(memcg->stat->count[i], cpu);
2227 per_cpu(memcg->stat->count[i], cpu) = 0;
2228 memcg->nocpu_base.count[i] += x;
2230 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2231 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2233 per_cpu(memcg->stat->events[i], cpu) = 0;
2234 memcg->nocpu_base.events[i] += x;
2236 spin_unlock(&memcg->pcp_counter_lock);
2239 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2240 unsigned long action,
2243 int cpu = (unsigned long)hcpu;
2244 struct memcg_stock_pcp *stock;
2245 struct mem_cgroup *iter;
2247 if (action == CPU_ONLINE)
2250 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2253 for_each_mem_cgroup(iter)
2254 mem_cgroup_drain_pcp_counter(iter, cpu);
2256 stock = &per_cpu(memcg_stock, cpu);
2261 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2262 unsigned int nr_pages)
2264 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2265 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2266 struct mem_cgroup *mem_over_limit;
2267 struct page_counter *counter;
2268 unsigned long nr_reclaimed;
2269 bool may_swap = true;
2270 bool drained = false;
2273 if (mem_cgroup_is_root(memcg))
2276 if (consume_stock(memcg, nr_pages))
2279 if (!do_swap_account ||
2280 !page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2281 if (!page_counter_try_charge(&memcg->memory, batch, &counter))
2283 if (do_swap_account)
2284 page_counter_uncharge(&memcg->memsw, batch);
2285 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2287 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2291 if (batch > nr_pages) {
2297 * Unlike in global OOM situations, memcg is not in a physical
2298 * memory shortage. Allow dying and OOM-killed tasks to
2299 * bypass the last charges so that they can exit quickly and
2300 * free their memory.
2302 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
2303 fatal_signal_pending(current) ||
2304 current->flags & PF_EXITING))
2307 if (unlikely(task_in_memcg_oom(current)))
2310 if (!(gfp_mask & __GFP_WAIT))
2313 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2314 gfp_mask, may_swap);
2316 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2320 drain_all_stock(mem_over_limit);
2325 if (gfp_mask & __GFP_NORETRY)
2328 * Even though the limit is exceeded at this point, reclaim
2329 * may have been able to free some pages. Retry the charge
2330 * before killing the task.
2332 * Only for regular pages, though: huge pages are rather
2333 * unlikely to succeed so close to the limit, and we fall back
2334 * to regular pages anyway in case of failure.
2336 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2339 * At task move, charge accounts can be doubly counted. So, it's
2340 * better to wait until the end of task_move if something is going on.
2342 if (mem_cgroup_wait_acct_move(mem_over_limit))
2348 if (gfp_mask & __GFP_NOFAIL)
2351 if (fatal_signal_pending(current))
2354 mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages));
2356 if (!(gfp_mask & __GFP_NOFAIL))
2362 css_get_many(&memcg->css, batch);
2363 if (batch > nr_pages)
2364 refill_stock(memcg, batch - nr_pages);
2369 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2371 if (mem_cgroup_is_root(memcg))
2374 page_counter_uncharge(&memcg->memory, nr_pages);
2375 if (do_swap_account)
2376 page_counter_uncharge(&memcg->memsw, nr_pages);
2378 css_put_many(&memcg->css, nr_pages);
2382 * A helper function to get mem_cgroup from ID. must be called under
2383 * rcu_read_lock(). The caller is responsible for calling
2384 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2385 * refcnt from swap can be called against removed memcg.)
2387 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2389 /* ID 0 is unused ID */
2392 return mem_cgroup_from_id(id);
2396 * try_get_mem_cgroup_from_page - look up page's memcg association
2399 * Look up, get a css reference, and return the memcg that owns @page.
2401 * The page must be locked to prevent racing with swap-in and page
2402 * cache charges. If coming from an unlocked page table, the caller
2403 * must ensure the page is on the LRU or this can race with charging.
2405 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2407 struct mem_cgroup *memcg;
2408 struct page_cgroup *pc;
2412 VM_BUG_ON_PAGE(!PageLocked(page), page);
2414 pc = lookup_page_cgroup(page);
2415 memcg = pc->mem_cgroup;
2418 if (!css_tryget_online(&memcg->css))
2420 } else if (PageSwapCache(page)) {
2421 ent.val = page_private(page);
2422 id = lookup_swap_cgroup_id(ent);
2424 memcg = mem_cgroup_lookup(id);
2425 if (memcg && !css_tryget_online(&memcg->css))
2432 static void lock_page_lru(struct page *page, int *isolated)
2434 struct zone *zone = page_zone(page);
2436 spin_lock_irq(&zone->lru_lock);
2437 if (PageLRU(page)) {
2438 struct lruvec *lruvec;
2440 lruvec = mem_cgroup_page_lruvec(page, zone);
2442 del_page_from_lru_list(page, lruvec, page_lru(page));
2448 static void unlock_page_lru(struct page *page, int isolated)
2450 struct zone *zone = page_zone(page);
2453 struct lruvec *lruvec;
2455 lruvec = mem_cgroup_page_lruvec(page, zone);
2456 VM_BUG_ON_PAGE(PageLRU(page), page);
2458 add_page_to_lru_list(page, lruvec, page_lru(page));
2460 spin_unlock_irq(&zone->lru_lock);
2463 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2466 struct page_cgroup *pc = lookup_page_cgroup(page);
2469 VM_BUG_ON_PAGE(pc->mem_cgroup, page);
2471 * we don't need page_cgroup_lock about tail pages, becase they are not
2472 * accessed by any other context at this point.
2476 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2477 * may already be on some other mem_cgroup's LRU. Take care of it.
2480 lock_page_lru(page, &isolated);
2483 * Nobody should be changing or seriously looking at
2484 * pc->mem_cgroup at this point:
2486 * - the page is uncharged
2488 * - the page is off-LRU
2490 * - an anonymous fault has exclusive page access, except for
2491 * a locked page table
2493 * - a page cache insertion, a swapin fault, or a migration
2494 * have the page locked
2496 pc->mem_cgroup = memcg;
2499 unlock_page_lru(page, isolated);
2502 #ifdef CONFIG_MEMCG_KMEM
2504 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2505 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2507 static DEFINE_MUTEX(memcg_slab_mutex);
2510 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2511 * in the memcg_cache_params struct.
2513 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2515 struct kmem_cache *cachep;
2517 VM_BUG_ON(p->is_root_cache);
2518 cachep = p->root_cache;
2519 return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
2522 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
2523 unsigned long nr_pages)
2525 struct page_counter *counter;
2528 ret = page_counter_try_charge(&memcg->kmem, nr_pages, &counter);
2532 ret = try_charge(memcg, gfp, nr_pages);
2533 if (ret == -EINTR) {
2535 * try_charge() chose to bypass to root due to OOM kill or
2536 * fatal signal. Since our only options are to either fail
2537 * the allocation or charge it to this cgroup, do it as a
2538 * temporary condition. But we can't fail. From a kmem/slab
2539 * perspective, the cache has already been selected, by
2540 * mem_cgroup_kmem_get_cache(), so it is too late to change
2543 * This condition will only trigger if the task entered
2544 * memcg_charge_kmem in a sane state, but was OOM-killed
2545 * during try_charge() above. Tasks that were already dying
2546 * when the allocation triggers should have been already
2547 * directed to the root cgroup in memcontrol.h
2549 page_counter_charge(&memcg->memory, nr_pages);
2550 if (do_swap_account)
2551 page_counter_charge(&memcg->memsw, nr_pages);
2552 css_get_many(&memcg->css, nr_pages);
2555 page_counter_uncharge(&memcg->kmem, nr_pages);
2560 static void memcg_uncharge_kmem(struct mem_cgroup *memcg,
2561 unsigned long nr_pages)
2563 page_counter_uncharge(&memcg->memory, nr_pages);
2564 if (do_swap_account)
2565 page_counter_uncharge(&memcg->memsw, nr_pages);
2567 page_counter_uncharge(&memcg->kmem, nr_pages);
2569 css_put_many(&memcg->css, nr_pages);
2573 * helper for acessing a memcg's index. It will be used as an index in the
2574 * child cache array in kmem_cache, and also to derive its name. This function
2575 * will return -1 when this is not a kmem-limited memcg.
2577 int memcg_cache_id(struct mem_cgroup *memcg)
2579 return memcg ? memcg->kmemcg_id : -1;
2582 static int memcg_alloc_cache_id(void)
2587 id = ida_simple_get(&kmem_limited_groups,
2588 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2592 if (id < memcg_limited_groups_array_size)
2596 * There's no space for the new id in memcg_caches arrays,
2597 * so we have to grow them.
2600 size = 2 * (id + 1);
2601 if (size < MEMCG_CACHES_MIN_SIZE)
2602 size = MEMCG_CACHES_MIN_SIZE;
2603 else if (size > MEMCG_CACHES_MAX_SIZE)
2604 size = MEMCG_CACHES_MAX_SIZE;
2606 mutex_lock(&memcg_slab_mutex);
2607 err = memcg_update_all_caches(size);
2608 mutex_unlock(&memcg_slab_mutex);
2611 ida_simple_remove(&kmem_limited_groups, id);
2617 static void memcg_free_cache_id(int id)
2619 ida_simple_remove(&kmem_limited_groups, id);
2623 * We should update the current array size iff all caches updates succeed. This
2624 * can only be done from the slab side. The slab mutex needs to be held when
2627 void memcg_update_array_size(int num)
2629 memcg_limited_groups_array_size = num;
2632 static void memcg_register_cache(struct mem_cgroup *memcg,
2633 struct kmem_cache *root_cache)
2635 static char memcg_name_buf[NAME_MAX + 1]; /* protected by
2637 struct kmem_cache *cachep;
2640 lockdep_assert_held(&memcg_slab_mutex);
2642 id = memcg_cache_id(memcg);
2645 * Since per-memcg caches are created asynchronously on first
2646 * allocation (see memcg_kmem_get_cache()), several threads can try to
2647 * create the same cache, but only one of them may succeed.
2649 if (cache_from_memcg_idx(root_cache, id))
2652 cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
2653 cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
2655 * If we could not create a memcg cache, do not complain, because
2656 * that's not critical at all as we can always proceed with the root
2662 css_get(&memcg->css);
2663 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
2666 * Since readers won't lock (see cache_from_memcg_idx()), we need a
2667 * barrier here to ensure nobody will see the kmem_cache partially
2672 BUG_ON(root_cache->memcg_params->memcg_caches[id]);
2673 root_cache->memcg_params->memcg_caches[id] = cachep;
2676 static void memcg_unregister_cache(struct kmem_cache *cachep)
2678 struct kmem_cache *root_cache;
2679 struct mem_cgroup *memcg;
2682 lockdep_assert_held(&memcg_slab_mutex);
2684 BUG_ON(is_root_cache(cachep));
2686 root_cache = cachep->memcg_params->root_cache;
2687 memcg = cachep->memcg_params->memcg;
2688 id = memcg_cache_id(memcg);
2690 BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
2691 root_cache->memcg_params->memcg_caches[id] = NULL;
2693 list_del(&cachep->memcg_params->list);
2695 kmem_cache_destroy(cachep);
2697 /* drop the reference taken in memcg_register_cache */
2698 css_put(&memcg->css);
2702 * During the creation a new cache, we need to disable our accounting mechanism
2703 * altogether. This is true even if we are not creating, but rather just
2704 * enqueing new caches to be created.
2706 * This is because that process will trigger allocations; some visible, like
2707 * explicit kmallocs to auxiliary data structures, name strings and internal
2708 * cache structures; some well concealed, like INIT_WORK() that can allocate
2709 * objects during debug.
2711 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
2712 * to it. This may not be a bounded recursion: since the first cache creation
2713 * failed to complete (waiting on the allocation), we'll just try to create the
2714 * cache again, failing at the same point.
2716 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
2717 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
2718 * inside the following two functions.
2720 static inline void memcg_stop_kmem_account(void)
2722 VM_BUG_ON(!current->mm);
2723 current->memcg_kmem_skip_account++;
2726 static inline void memcg_resume_kmem_account(void)
2728 VM_BUG_ON(!current->mm);
2729 current->memcg_kmem_skip_account--;
2732 int __memcg_cleanup_cache_params(struct kmem_cache *s)
2734 struct kmem_cache *c;
2737 mutex_lock(&memcg_slab_mutex);
2738 for_each_memcg_cache_index(i) {
2739 c = cache_from_memcg_idx(s, i);
2743 memcg_unregister_cache(c);
2745 if (cache_from_memcg_idx(s, i))
2748 mutex_unlock(&memcg_slab_mutex);
2752 static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
2754 struct kmem_cache *cachep;
2755 struct memcg_cache_params *params, *tmp;
2757 if (!memcg_kmem_is_active(memcg))
2760 mutex_lock(&memcg_slab_mutex);
2761 list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
2762 cachep = memcg_params_to_cache(params);
2763 kmem_cache_shrink(cachep);
2764 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
2765 memcg_unregister_cache(cachep);
2767 mutex_unlock(&memcg_slab_mutex);
2770 struct memcg_register_cache_work {
2771 struct mem_cgroup *memcg;
2772 struct kmem_cache *cachep;
2773 struct work_struct work;
2776 static void memcg_register_cache_func(struct work_struct *w)
2778 struct memcg_register_cache_work *cw =
2779 container_of(w, struct memcg_register_cache_work, work);
2780 struct mem_cgroup *memcg = cw->memcg;
2781 struct kmem_cache *cachep = cw->cachep;
2783 mutex_lock(&memcg_slab_mutex);
2784 memcg_register_cache(memcg, cachep);
2785 mutex_unlock(&memcg_slab_mutex);
2787 css_put(&memcg->css);
2792 * Enqueue the creation of a per-memcg kmem_cache.
2794 static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
2795 struct kmem_cache *cachep)
2797 struct memcg_register_cache_work *cw;
2799 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
2801 css_put(&memcg->css);
2806 cw->cachep = cachep;
2808 INIT_WORK(&cw->work, memcg_register_cache_func);
2809 schedule_work(&cw->work);
2812 static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
2813 struct kmem_cache *cachep)
2816 * We need to stop accounting when we kmalloc, because if the
2817 * corresponding kmalloc cache is not yet created, the first allocation
2818 * in __memcg_schedule_register_cache will recurse.
2820 * However, it is better to enclose the whole function. Depending on
2821 * the debugging options enabled, INIT_WORK(), for instance, can
2822 * trigger an allocation. This too, will make us recurse. Because at
2823 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2824 * the safest choice is to do it like this, wrapping the whole function.
2826 memcg_stop_kmem_account();
2827 __memcg_schedule_register_cache(memcg, cachep);
2828 memcg_resume_kmem_account();
2831 int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
2833 unsigned int nr_pages = 1 << order;
2836 res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp, nr_pages);
2838 atomic_add(nr_pages, &cachep->memcg_params->nr_pages);
2842 void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
2844 unsigned int nr_pages = 1 << order;
2846 memcg_uncharge_kmem(cachep->memcg_params->memcg, nr_pages);
2847 atomic_sub(nr_pages, &cachep->memcg_params->nr_pages);
2851 * Return the kmem_cache we're supposed to use for a slab allocation.
2852 * We try to use the current memcg's version of the cache.
2854 * If the cache does not exist yet, if we are the first user of it,
2855 * we either create it immediately, if possible, or create it asynchronously
2857 * In the latter case, we will let the current allocation go through with
2858 * the original cache.
2860 * Can't be called in interrupt context or from kernel threads.
2861 * This function needs to be called with rcu_read_lock() held.
2863 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
2866 struct mem_cgroup *memcg;
2867 struct kmem_cache *memcg_cachep;
2869 VM_BUG_ON(!cachep->memcg_params);
2870 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
2872 if (!current->mm || current->memcg_kmem_skip_account)
2876 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
2878 if (!memcg_kmem_is_active(memcg))
2881 memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
2882 if (likely(memcg_cachep)) {
2883 cachep = memcg_cachep;
2887 /* The corresponding put will be done in the workqueue. */
2888 if (!css_tryget_online(&memcg->css))
2893 * If we are in a safe context (can wait, and not in interrupt
2894 * context), we could be be predictable and return right away.
2895 * This would guarantee that the allocation being performed
2896 * already belongs in the new cache.
2898 * However, there are some clashes that can arrive from locking.
2899 * For instance, because we acquire the slab_mutex while doing
2900 * memcg_create_kmem_cache, this means no further allocation
2901 * could happen with the slab_mutex held. So it's better to
2904 memcg_schedule_register_cache(memcg, cachep);
2912 * We need to verify if the allocation against current->mm->owner's memcg is
2913 * possible for the given order. But the page is not allocated yet, so we'll
2914 * need a further commit step to do the final arrangements.
2916 * It is possible for the task to switch cgroups in this mean time, so at
2917 * commit time, we can't rely on task conversion any longer. We'll then use
2918 * the handle argument to return to the caller which cgroup we should commit
2919 * against. We could also return the memcg directly and avoid the pointer
2920 * passing, but a boolean return value gives better semantics considering
2921 * the compiled-out case as well.
2923 * Returning true means the allocation is possible.
2926 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
2928 struct mem_cgroup *memcg;
2934 * Disabling accounting is only relevant for some specific memcg
2935 * internal allocations. Therefore we would initially not have such
2936 * check here, since direct calls to the page allocator that are
2937 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
2938 * outside memcg core. We are mostly concerned with cache allocations,
2939 * and by having this test at memcg_kmem_get_cache, we are already able
2940 * to relay the allocation to the root cache and bypass the memcg cache
2943 * There is one exception, though: the SLUB allocator does not create
2944 * large order caches, but rather service large kmallocs directly from
2945 * the page allocator. Therefore, the following sequence when backed by
2946 * the SLUB allocator:
2948 * memcg_stop_kmem_account();
2949 * kmalloc(<large_number>)
2950 * memcg_resume_kmem_account();
2952 * would effectively ignore the fact that we should skip accounting,
2953 * since it will drive us directly to this function without passing
2954 * through the cache selector memcg_kmem_get_cache. Such large
2955 * allocations are extremely rare but can happen, for instance, for the
2956 * cache arrays. We bring this test here.
2958 if (!current->mm || current->memcg_kmem_skip_account)
2961 memcg = get_mem_cgroup_from_mm(current->mm);
2963 if (!memcg_kmem_is_active(memcg)) {
2964 css_put(&memcg->css);
2968 ret = memcg_charge_kmem(memcg, gfp, 1 << order);
2972 css_put(&memcg->css);
2976 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
2979 struct page_cgroup *pc;
2981 VM_BUG_ON(mem_cgroup_is_root(memcg));
2983 /* The page allocation failed. Revert */
2985 memcg_uncharge_kmem(memcg, 1 << order);
2988 pc = lookup_page_cgroup(page);
2989 pc->mem_cgroup = memcg;
2992 void __memcg_kmem_uncharge_pages(struct page *page, int order)
2994 struct page_cgroup *pc = lookup_page_cgroup(page);
2995 struct mem_cgroup *memcg = pc->mem_cgroup;
3000 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
3002 memcg_uncharge_kmem(memcg, 1 << order);
3003 pc->mem_cgroup = NULL;
3006 static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
3009 #endif /* CONFIG_MEMCG_KMEM */
3011 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3014 * Because tail pages are not marked as "used", set it. We're under
3015 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3016 * charge/uncharge will be never happen and move_account() is done under
3017 * compound_lock(), so we don't have to take care of races.
3019 void mem_cgroup_split_huge_fixup(struct page *head)
3021 struct page_cgroup *pc = lookup_page_cgroup(head);
3024 if (mem_cgroup_disabled())
3027 for (i = 1; i < HPAGE_PMD_NR; i++)
3028 pc[i].mem_cgroup = pc[0].mem_cgroup;
3030 __this_cpu_sub(pc[0].mem_cgroup->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3033 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3036 * mem_cgroup_move_account - move account of the page
3038 * @nr_pages: number of regular pages (>1 for huge pages)
3039 * @pc: page_cgroup of the page.
3040 * @from: mem_cgroup which the page is moved from.
3041 * @to: mem_cgroup which the page is moved to. @from != @to.
3043 * The caller must confirm following.
3044 * - page is not on LRU (isolate_page() is useful.)
3045 * - compound_lock is held when nr_pages > 1
3047 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3050 static int mem_cgroup_move_account(struct page *page,
3051 unsigned int nr_pages,
3052 struct page_cgroup *pc,
3053 struct mem_cgroup *from,
3054 struct mem_cgroup *to)
3056 unsigned long flags;
3059 VM_BUG_ON(from == to);
3060 VM_BUG_ON_PAGE(PageLRU(page), page);
3062 * The page is isolated from LRU. So, collapse function
3063 * will not handle this page. But page splitting can happen.
3064 * Do this check under compound_page_lock(). The caller should
3068 if (nr_pages > 1 && !PageTransHuge(page))
3072 * Prevent mem_cgroup_migrate() from looking at pc->mem_cgroup
3073 * of its source page while we change it: page migration takes
3074 * both pages off the LRU, but page cache replacement doesn't.
3076 if (!trylock_page(page))
3080 if (pc->mem_cgroup != from)
3083 spin_lock_irqsave(&from->move_lock, flags);
3085 if (!PageAnon(page) && page_mapped(page)) {
3086 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3088 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3092 if (PageWriteback(page)) {
3093 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3095 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3100 * It is safe to change pc->mem_cgroup here because the page
3101 * is referenced, charged, and isolated - we can't race with
3102 * uncharging, charging, migration, or LRU putback.
3105 /* caller should have done css_get */
3106 pc->mem_cgroup = to;
3107 spin_unlock_irqrestore(&from->move_lock, flags);
3111 local_irq_disable();
3112 mem_cgroup_charge_statistics(to, page, nr_pages);
3113 memcg_check_events(to, page);
3114 mem_cgroup_charge_statistics(from, page, -nr_pages);
3115 memcg_check_events(from, page);
3123 #ifdef CONFIG_MEMCG_SWAP
3124 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
3127 int val = (charge) ? 1 : -1;
3128 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
3132 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3133 * @entry: swap entry to be moved
3134 * @from: mem_cgroup which the entry is moved from
3135 * @to: mem_cgroup which the entry is moved to
3137 * It succeeds only when the swap_cgroup's record for this entry is the same
3138 * as the mem_cgroup's id of @from.
3140 * Returns 0 on success, -EINVAL on failure.
3142 * The caller must have charged to @to, IOW, called page_counter_charge() about
3143 * both res and memsw, and called css_get().
3145 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3146 struct mem_cgroup *from, struct mem_cgroup *to)
3148 unsigned short old_id, new_id;
3150 old_id = mem_cgroup_id(from);
3151 new_id = mem_cgroup_id(to);
3153 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3154 mem_cgroup_swap_statistics(from, false);
3155 mem_cgroup_swap_statistics(to, true);
3157 * This function is only called from task migration context now.
3158 * It postpones page_counter and refcount handling till the end
3159 * of task migration(mem_cgroup_clear_mc()) for performance
3160 * improvement. But we cannot postpone css_get(to) because if
3161 * the process that has been moved to @to does swap-in, the
3162 * refcount of @to might be decreased to 0.
3164 * We are in attach() phase, so the cgroup is guaranteed to be
3165 * alive, so we can just call css_get().
3173 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3174 struct mem_cgroup *from, struct mem_cgroup *to)
3180 #ifdef CONFIG_DEBUG_VM
3181 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3183 struct page_cgroup *pc;
3185 pc = lookup_page_cgroup(page);
3187 * Can be NULL while feeding pages into the page allocator for
3188 * the first time, i.e. during boot or memory hotplug;
3189 * or when mem_cgroup_disabled().
3191 if (likely(pc) && pc->mem_cgroup)
3196 bool mem_cgroup_bad_page_check(struct page *page)
3198 if (mem_cgroup_disabled())
3201 return lookup_page_cgroup_used(page) != NULL;
3204 void mem_cgroup_print_bad_page(struct page *page)
3206 struct page_cgroup *pc;
3208 pc = lookup_page_cgroup_used(page);
3210 pr_alert("pc:%p pc->mem_cgroup:%p\n", pc, pc->mem_cgroup);
3214 static DEFINE_MUTEX(memcg_limit_mutex);
3216 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3217 unsigned long limit)
3219 unsigned long curusage;
3220 unsigned long oldusage;
3221 bool enlarge = false;
3226 * For keeping hierarchical_reclaim simple, how long we should retry
3227 * is depends on callers. We set our retry-count to be function
3228 * of # of children which we should visit in this loop.
3230 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
3231 mem_cgroup_count_children(memcg);
3233 oldusage = page_counter_read(&memcg->memory);
3236 if (signal_pending(current)) {
3241 mutex_lock(&memcg_limit_mutex);
3242 if (limit > memcg->memsw.limit) {
3243 mutex_unlock(&memcg_limit_mutex);
3247 if (limit > memcg->memory.limit)
3249 ret = page_counter_limit(&memcg->memory, limit);
3250 mutex_unlock(&memcg_limit_mutex);
3255 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
3257 curusage = page_counter_read(&memcg->memory);
3258 /* Usage is reduced ? */
3259 if (curusage >= oldusage)
3262 oldusage = curusage;
3263 } while (retry_count);
3265 if (!ret && enlarge)
3266 memcg_oom_recover(memcg);
3271 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3272 unsigned long limit)
3274 unsigned long curusage;
3275 unsigned long oldusage;
3276 bool enlarge = false;
3280 /* see mem_cgroup_resize_res_limit */
3281 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
3282 mem_cgroup_count_children(memcg);
3284 oldusage = page_counter_read(&memcg->memsw);
3287 if (signal_pending(current)) {
3292 mutex_lock(&memcg_limit_mutex);
3293 if (limit < memcg->memory.limit) {
3294 mutex_unlock(&memcg_limit_mutex);
3298 if (limit > memcg->memsw.limit)
3300 ret = page_counter_limit(&memcg->memsw, limit);
3301 mutex_unlock(&memcg_limit_mutex);
3306 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
3308 curusage = page_counter_read(&memcg->memsw);
3309 /* Usage is reduced ? */
3310 if (curusage >= oldusage)
3313 oldusage = curusage;
3314 } while (retry_count);
3316 if (!ret && enlarge)
3317 memcg_oom_recover(memcg);
3322 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3324 unsigned long *total_scanned)
3326 unsigned long nr_reclaimed = 0;
3327 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3328 unsigned long reclaimed;
3330 struct mem_cgroup_tree_per_zone *mctz;
3331 unsigned long excess;
3332 unsigned long nr_scanned;
3337 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3339 * This loop can run a while, specially if mem_cgroup's continuously
3340 * keep exceeding their soft limit and putting the system under
3347 mz = mem_cgroup_largest_soft_limit_node(mctz);
3352 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
3353 gfp_mask, &nr_scanned);
3354 nr_reclaimed += reclaimed;
3355 *total_scanned += nr_scanned;
3356 spin_lock_irq(&mctz->lock);
3357 __mem_cgroup_remove_exceeded(mz, mctz);
3360 * If we failed to reclaim anything from this memory cgroup
3361 * it is time to move on to the next cgroup
3365 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3367 excess = soft_limit_excess(mz->memcg);
3369 * One school of thought says that we should not add
3370 * back the node to the tree if reclaim returns 0.
3371 * But our reclaim could return 0, simply because due
3372 * to priority we are exposing a smaller subset of
3373 * memory to reclaim from. Consider this as a longer
3376 /* If excess == 0, no tree ops */
3377 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3378 spin_unlock_irq(&mctz->lock);
3379 css_put(&mz->memcg->css);
3382 * Could not reclaim anything and there are no more
3383 * mem cgroups to try or we seem to be looping without
3384 * reclaiming anything.
3386 if (!nr_reclaimed &&
3388 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3390 } while (!nr_reclaimed);
3392 css_put(&next_mz->memcg->css);
3393 return nr_reclaimed;
3397 * Test whether @memcg has children, dead or alive. Note that this
3398 * function doesn't care whether @memcg has use_hierarchy enabled and
3399 * returns %true if there are child csses according to the cgroup
3400 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
3402 static inline bool memcg_has_children(struct mem_cgroup *memcg)
3407 * The lock does not prevent addition or deletion of children, but
3408 * it prevents a new child from being initialized based on this
3409 * parent in css_online(), so it's enough to decide whether
3410 * hierarchically inherited attributes can still be changed or not.
3412 lockdep_assert_held(&memcg_create_mutex);
3415 ret = css_next_child(NULL, &memcg->css);
3421 * Reclaims as many pages from the given memcg as possible and moves
3422 * the rest to the parent.
3424 * Caller is responsible for holding css reference for memcg.
3426 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3428 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3430 /* we call try-to-free pages for make this cgroup empty */
3431 lru_add_drain_all();
3432 /* try to free all pages in this cgroup */
3433 while (nr_retries && page_counter_read(&memcg->memory)) {
3436 if (signal_pending(current))
3439 progress = try_to_free_mem_cgroup_pages(memcg, 1,
3443 /* maybe some writeback is necessary */
3444 congestion_wait(BLK_RW_ASYNC, HZ/10);
3452 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3453 char *buf, size_t nbytes,
3456 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3458 if (mem_cgroup_is_root(memcg))
3460 return mem_cgroup_force_empty(memcg) ?: nbytes;
3463 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3466 return mem_cgroup_from_css(css)->use_hierarchy;
3469 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3470 struct cftype *cft, u64 val)
3473 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3474 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
3476 mutex_lock(&memcg_create_mutex);
3478 if (memcg->use_hierarchy == val)
3482 * If parent's use_hierarchy is set, we can't make any modifications
3483 * in the child subtrees. If it is unset, then the change can
3484 * occur, provided the current cgroup has no children.
3486 * For the root cgroup, parent_mem is NULL, we allow value to be
3487 * set if there are no children.
3489 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3490 (val == 1 || val == 0)) {
3491 if (!memcg_has_children(memcg))
3492 memcg->use_hierarchy = val;
3499 mutex_unlock(&memcg_create_mutex);
3504 static unsigned long tree_stat(struct mem_cgroup *memcg,
3505 enum mem_cgroup_stat_index idx)
3507 struct mem_cgroup *iter;
3510 /* Per-cpu values can be negative, use a signed accumulator */
3511 for_each_mem_cgroup_tree(iter, memcg)
3512 val += mem_cgroup_read_stat(iter, idx);
3514 if (val < 0) /* race ? */
3519 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3523 if (mem_cgroup_is_root(memcg)) {
3524 val = tree_stat(memcg, MEM_CGROUP_STAT_CACHE);
3525 val += tree_stat(memcg, MEM_CGROUP_STAT_RSS);
3527 val += tree_stat(memcg, MEM_CGROUP_STAT_SWAP);
3530 val = page_counter_read(&memcg->memory);
3532 val = page_counter_read(&memcg->memsw);
3534 return val << PAGE_SHIFT;
3545 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3548 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3549 struct page_counter *counter;
3551 switch (MEMFILE_TYPE(cft->private)) {
3553 counter = &memcg->memory;
3556 counter = &memcg->memsw;
3559 counter = &memcg->kmem;
3565 switch (MEMFILE_ATTR(cft->private)) {
3567 if (counter == &memcg->memory)
3568 return mem_cgroup_usage(memcg, false);
3569 if (counter == &memcg->memsw)
3570 return mem_cgroup_usage(memcg, true);
3571 return (u64)page_counter_read(counter) * PAGE_SIZE;
3573 return (u64)counter->limit * PAGE_SIZE;
3575 return (u64)counter->watermark * PAGE_SIZE;
3577 return counter->failcnt;
3578 case RES_SOFT_LIMIT:
3579 return (u64)memcg->soft_limit * PAGE_SIZE;
3585 #ifdef CONFIG_MEMCG_KMEM
3586 static int memcg_activate_kmem(struct mem_cgroup *memcg,
3587 unsigned long nr_pages)
3592 if (memcg_kmem_is_active(memcg))
3596 * We are going to allocate memory for data shared by all memory
3597 * cgroups so let's stop accounting here.
3599 memcg_stop_kmem_account();
3602 * For simplicity, we won't allow this to be disabled. It also can't
3603 * be changed if the cgroup has children already, or if tasks had
3606 * If tasks join before we set the limit, a person looking at
3607 * kmem.usage_in_bytes will have no way to determine when it took
3608 * place, which makes the value quite meaningless.
3610 * After it first became limited, changes in the value of the limit are
3611 * of course permitted.
3613 mutex_lock(&memcg_create_mutex);
3614 if (cgroup_has_tasks(memcg->css.cgroup) ||
3615 (memcg->use_hierarchy && memcg_has_children(memcg)))
3617 mutex_unlock(&memcg_create_mutex);
3621 memcg_id = memcg_alloc_cache_id();
3627 memcg->kmemcg_id = memcg_id;
3628 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
3631 * We couldn't have accounted to this cgroup, because it hasn't got the
3632 * active bit set yet, so this should succeed.
3634 err = page_counter_limit(&memcg->kmem, nr_pages);
3637 static_key_slow_inc(&memcg_kmem_enabled_key);
3639 * Setting the active bit after enabling static branching will
3640 * guarantee no one starts accounting before all call sites are
3643 memcg_kmem_set_active(memcg);
3645 memcg_resume_kmem_account();
3649 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
3650 unsigned long limit)
3654 mutex_lock(&memcg_limit_mutex);
3655 if (!memcg_kmem_is_active(memcg))
3656 ret = memcg_activate_kmem(memcg, limit);
3658 ret = page_counter_limit(&memcg->kmem, limit);
3659 mutex_unlock(&memcg_limit_mutex);
3663 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
3666 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
3671 mutex_lock(&memcg_limit_mutex);
3673 * If the parent cgroup is not kmem-active now, it cannot be activated
3674 * after this point, because it has at least one child already.
3676 if (memcg_kmem_is_active(parent))
3677 ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
3678 mutex_unlock(&memcg_limit_mutex);
3682 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
3683 unsigned long limit)
3687 #endif /* CONFIG_MEMCG_KMEM */
3690 * The user of this function is...
3693 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3694 char *buf, size_t nbytes, loff_t off)
3696 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3697 unsigned long nr_pages;
3700 buf = strstrip(buf);
3701 ret = page_counter_memparse(buf, &nr_pages);
3705 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3707 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3711 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3713 ret = mem_cgroup_resize_limit(memcg, nr_pages);
3716 ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
3719 ret = memcg_update_kmem_limit(memcg, nr_pages);
3723 case RES_SOFT_LIMIT:
3724 memcg->soft_limit = nr_pages;
3728 return ret ?: nbytes;
3731 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3732 size_t nbytes, loff_t off)
3734 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3735 struct page_counter *counter;
3737 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3739 counter = &memcg->memory;
3742 counter = &memcg->memsw;
3745 counter = &memcg->kmem;
3751 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3753 page_counter_reset_watermark(counter);
3756 counter->failcnt = 0;
3765 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3768 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3772 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3773 struct cftype *cft, u64 val)
3775 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3777 if (val >= (1 << NR_MOVE_TYPE))
3781 * No kind of locking is needed in here, because ->can_attach() will
3782 * check this value once in the beginning of the process, and then carry
3783 * on with stale data. This means that changes to this value will only
3784 * affect task migrations starting after the change.
3786 memcg->move_charge_at_immigrate = val;
3790 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3791 struct cftype *cft, u64 val)
3798 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3802 unsigned int lru_mask;
3805 static const struct numa_stat stats[] = {
3806 { "total", LRU_ALL },
3807 { "file", LRU_ALL_FILE },
3808 { "anon", LRU_ALL_ANON },
3809 { "unevictable", BIT(LRU_UNEVICTABLE) },
3811 const struct numa_stat *stat;
3814 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3816 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3817 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
3818 seq_printf(m, "%s=%lu", stat->name, nr);
3819 for_each_node_state(nid, N_MEMORY) {
3820 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
3822 seq_printf(m, " N%d=%lu", nid, nr);
3827 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3828 struct mem_cgroup *iter;
3831 for_each_mem_cgroup_tree(iter, memcg)
3832 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
3833 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
3834 for_each_node_state(nid, N_MEMORY) {
3836 for_each_mem_cgroup_tree(iter, memcg)
3837 nr += mem_cgroup_node_nr_lru_pages(
3838 iter, nid, stat->lru_mask);
3839 seq_printf(m, " N%d=%lu", nid, nr);
3846 #endif /* CONFIG_NUMA */
3848 static inline void mem_cgroup_lru_names_not_uptodate(void)
3850 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
3853 static int memcg_stat_show(struct seq_file *m, void *v)
3855 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3856 unsigned long memory, memsw;
3857 struct mem_cgroup *mi;
3860 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3861 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
3863 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
3864 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
3867 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
3868 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
3869 mem_cgroup_read_events(memcg, i));
3871 for (i = 0; i < NR_LRU_LISTS; i++)
3872 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
3873 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
3875 /* Hierarchical information */
3876 memory = memsw = PAGE_COUNTER_MAX;
3877 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
3878 memory = min(memory, mi->memory.limit);
3879 memsw = min(memsw, mi->memsw.limit);
3881 seq_printf(m, "hierarchical_memory_limit %llu\n",
3882 (u64)memory * PAGE_SIZE);
3883 if (do_swap_account)
3884 seq_printf(m, "hierarchical_memsw_limit %llu\n",
3885 (u64)memsw * PAGE_SIZE);
3887 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3890 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
3892 for_each_mem_cgroup_tree(mi, memcg)
3893 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
3894 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
3897 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
3898 unsigned long long val = 0;
3900 for_each_mem_cgroup_tree(mi, memcg)
3901 val += mem_cgroup_read_events(mi, i);
3902 seq_printf(m, "total_%s %llu\n",
3903 mem_cgroup_events_names[i], val);
3906 for (i = 0; i < NR_LRU_LISTS; i++) {
3907 unsigned long long val = 0;
3909 for_each_mem_cgroup_tree(mi, memcg)
3910 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
3911 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
3914 #ifdef CONFIG_DEBUG_VM
3917 struct mem_cgroup_per_zone *mz;
3918 struct zone_reclaim_stat *rstat;
3919 unsigned long recent_rotated[2] = {0, 0};
3920 unsigned long recent_scanned[2] = {0, 0};
3922 for_each_online_node(nid)
3923 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3924 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
3925 rstat = &mz->lruvec.reclaim_stat;
3927 recent_rotated[0] += rstat->recent_rotated[0];
3928 recent_rotated[1] += rstat->recent_rotated[1];
3929 recent_scanned[0] += rstat->recent_scanned[0];
3930 recent_scanned[1] += rstat->recent_scanned[1];
3932 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
3933 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
3934 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
3935 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
3942 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
3945 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3947 return mem_cgroup_swappiness(memcg);
3950 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
3951 struct cftype *cft, u64 val)
3953 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3959 memcg->swappiness = val;
3961 vm_swappiness = val;
3966 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3968 struct mem_cgroup_threshold_ary *t;
3969 unsigned long usage;
3974 t = rcu_dereference(memcg->thresholds.primary);
3976 t = rcu_dereference(memcg->memsw_thresholds.primary);
3981 usage = mem_cgroup_usage(memcg, swap);
3984 * current_threshold points to threshold just below or equal to usage.
3985 * If it's not true, a threshold was crossed after last
3986 * call of __mem_cgroup_threshold().
3988 i = t->current_threshold;
3991 * Iterate backward over array of thresholds starting from
3992 * current_threshold and check if a threshold is crossed.
3993 * If none of thresholds below usage is crossed, we read
3994 * only one element of the array here.
3996 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3997 eventfd_signal(t->entries[i].eventfd, 1);
3999 /* i = current_threshold + 1 */
4003 * Iterate forward over array of thresholds starting from
4004 * current_threshold+1 and check if a threshold is crossed.
4005 * If none of thresholds above usage is crossed, we read
4006 * only one element of the array here.
4008 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4009 eventfd_signal(t->entries[i].eventfd, 1);
4011 /* Update current_threshold */
4012 t->current_threshold = i - 1;
4017 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4020 __mem_cgroup_threshold(memcg, false);
4021 if (do_swap_account)
4022 __mem_cgroup_threshold(memcg, true);
4024 memcg = parent_mem_cgroup(memcg);
4028 static int compare_thresholds(const void *a, const void *b)
4030 const struct mem_cgroup_threshold *_a = a;
4031 const struct mem_cgroup_threshold *_b = b;
4033 if (_a->threshold > _b->threshold)
4036 if (_a->threshold < _b->threshold)
4042 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4044 struct mem_cgroup_eventfd_list *ev;
4046 spin_lock(&memcg_oom_lock);
4048 list_for_each_entry(ev, &memcg->oom_notify, list)
4049 eventfd_signal(ev->eventfd, 1);
4051 spin_unlock(&memcg_oom_lock);
4055 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4057 struct mem_cgroup *iter;
4059 for_each_mem_cgroup_tree(iter, memcg)
4060 mem_cgroup_oom_notify_cb(iter);
4063 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4064 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4066 struct mem_cgroup_thresholds *thresholds;
4067 struct mem_cgroup_threshold_ary *new;
4068 unsigned long threshold;
4069 unsigned long usage;
4072 ret = page_counter_memparse(args, &threshold);
4076 mutex_lock(&memcg->thresholds_lock);
4079 thresholds = &memcg->thresholds;
4080 usage = mem_cgroup_usage(memcg, false);
4081 } else if (type == _MEMSWAP) {
4082 thresholds = &memcg->memsw_thresholds;
4083 usage = mem_cgroup_usage(memcg, true);
4087 /* Check if a threshold crossed before adding a new one */
4088 if (thresholds->primary)
4089 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4091 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4093 /* Allocate memory for new array of thresholds */
4094 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4102 /* Copy thresholds (if any) to new array */
4103 if (thresholds->primary) {
4104 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4105 sizeof(struct mem_cgroup_threshold));
4108 /* Add new threshold */
4109 new->entries[size - 1].eventfd = eventfd;
4110 new->entries[size - 1].threshold = threshold;
4112 /* Sort thresholds. Registering of new threshold isn't time-critical */
4113 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4114 compare_thresholds, NULL);
4116 /* Find current threshold */
4117 new->current_threshold = -1;
4118 for (i = 0; i < size; i++) {
4119 if (new->entries[i].threshold <= usage) {
4121 * new->current_threshold will not be used until
4122 * rcu_assign_pointer(), so it's safe to increment
4125 ++new->current_threshold;
4130 /* Free old spare buffer and save old primary buffer as spare */
4131 kfree(thresholds->spare);
4132 thresholds->spare = thresholds->primary;
4134 rcu_assign_pointer(thresholds->primary, new);
4136 /* To be sure that nobody uses thresholds */
4140 mutex_unlock(&memcg->thresholds_lock);
4145 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4146 struct eventfd_ctx *eventfd, const char *args)
4148 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4151 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4152 struct eventfd_ctx *eventfd, const char *args)
4154 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4157 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4158 struct eventfd_ctx *eventfd, enum res_type type)
4160 struct mem_cgroup_thresholds *thresholds;
4161 struct mem_cgroup_threshold_ary *new;
4162 unsigned long usage;
4165 mutex_lock(&memcg->thresholds_lock);
4168 thresholds = &memcg->thresholds;
4169 usage = mem_cgroup_usage(memcg, false);
4170 } else if (type == _MEMSWAP) {
4171 thresholds = &memcg->memsw_thresholds;
4172 usage = mem_cgroup_usage(memcg, true);
4176 if (!thresholds->primary)
4179 /* Check if a threshold crossed before removing */
4180 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4182 /* Calculate new number of threshold */
4184 for (i = 0; i < thresholds->primary->size; i++) {
4185 if (thresholds->primary->entries[i].eventfd != eventfd)
4189 new = thresholds->spare;
4191 /* Set thresholds array to NULL if we don't have thresholds */
4200 /* Copy thresholds and find current threshold */
4201 new->current_threshold = -1;
4202 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4203 if (thresholds->primary->entries[i].eventfd == eventfd)
4206 new->entries[j] = thresholds->primary->entries[i];
4207 if (new->entries[j].threshold <= usage) {
4209 * new->current_threshold will not be used
4210 * until rcu_assign_pointer(), so it's safe to increment
4213 ++new->current_threshold;
4219 /* Swap primary and spare array */
4220 thresholds->spare = thresholds->primary;
4221 /* If all events are unregistered, free the spare array */
4223 kfree(thresholds->spare);
4224 thresholds->spare = NULL;
4227 rcu_assign_pointer(thresholds->primary, new);
4229 /* To be sure that nobody uses thresholds */
4232 mutex_unlock(&memcg->thresholds_lock);
4235 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4236 struct eventfd_ctx *eventfd)
4238 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4241 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4242 struct eventfd_ctx *eventfd)
4244 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4247 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4248 struct eventfd_ctx *eventfd, const char *args)
4250 struct mem_cgroup_eventfd_list *event;
4252 event = kmalloc(sizeof(*event), GFP_KERNEL);
4256 spin_lock(&memcg_oom_lock);
4258 event->eventfd = eventfd;
4259 list_add(&event->list, &memcg->oom_notify);
4261 /* already in OOM ? */
4262 if (atomic_read(&memcg->under_oom))
4263 eventfd_signal(eventfd, 1);
4264 spin_unlock(&memcg_oom_lock);
4269 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4270 struct eventfd_ctx *eventfd)
4272 struct mem_cgroup_eventfd_list *ev, *tmp;
4274 spin_lock(&memcg_oom_lock);
4276 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4277 if (ev->eventfd == eventfd) {
4278 list_del(&ev->list);
4283 spin_unlock(&memcg_oom_lock);
4286 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4288 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
4290 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4291 seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
4295 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4296 struct cftype *cft, u64 val)
4298 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4300 /* cannot set to root cgroup and only 0 and 1 are allowed */
4301 if (!css->parent || !((val == 0) || (val == 1)))
4304 memcg->oom_kill_disable = val;
4306 memcg_oom_recover(memcg);
4311 #ifdef CONFIG_MEMCG_KMEM
4312 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4316 memcg->kmemcg_id = -1;
4317 ret = memcg_propagate_kmem(memcg);
4321 return mem_cgroup_sockets_init(memcg, ss);
4324 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
4326 mem_cgroup_sockets_destroy(memcg);
4329 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4334 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
4340 * DO NOT USE IN NEW FILES.
4342 * "cgroup.event_control" implementation.
4344 * This is way over-engineered. It tries to support fully configurable
4345 * events for each user. Such level of flexibility is completely
4346 * unnecessary especially in the light of the planned unified hierarchy.
4348 * Please deprecate this and replace with something simpler if at all
4353 * Unregister event and free resources.
4355 * Gets called from workqueue.
4357 static void memcg_event_remove(struct work_struct *work)
4359 struct mem_cgroup_event *event =
4360 container_of(work, struct mem_cgroup_event, remove);
4361 struct mem_cgroup *memcg = event->memcg;
4363 remove_wait_queue(event->wqh, &event->wait);
4365 event->unregister_event(memcg, event->eventfd);
4367 /* Notify userspace the event is going away. */
4368 eventfd_signal(event->eventfd, 1);
4370 eventfd_ctx_put(event->eventfd);
4372 css_put(&memcg->css);
4376 * Gets called on POLLHUP on eventfd when user closes it.
4378 * Called with wqh->lock held and interrupts disabled.
4380 static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
4381 int sync, void *key)
4383 struct mem_cgroup_event *event =
4384 container_of(wait, struct mem_cgroup_event, wait);
4385 struct mem_cgroup *memcg = event->memcg;
4386 unsigned long flags = (unsigned long)key;
4388 if (flags & POLLHUP) {
4390 * If the event has been detached at cgroup removal, we
4391 * can simply return knowing the other side will cleanup
4394 * We can't race against event freeing since the other
4395 * side will require wqh->lock via remove_wait_queue(),
4398 spin_lock(&memcg->event_list_lock);
4399 if (!list_empty(&event->list)) {
4400 list_del_init(&event->list);
4402 * We are in atomic context, but cgroup_event_remove()
4403 * may sleep, so we have to call it in workqueue.
4405 schedule_work(&event->remove);
4407 spin_unlock(&memcg->event_list_lock);
4413 static void memcg_event_ptable_queue_proc(struct file *file,
4414 wait_queue_head_t *wqh, poll_table *pt)
4416 struct mem_cgroup_event *event =
4417 container_of(pt, struct mem_cgroup_event, pt);
4420 add_wait_queue(wqh, &event->wait);
4424 * DO NOT USE IN NEW FILES.
4426 * Parse input and register new cgroup event handler.
4428 * Input must be in format '<event_fd> <control_fd> <args>'.
4429 * Interpretation of args is defined by control file implementation.
4431 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4432 char *buf, size_t nbytes, loff_t off)
4434 struct cgroup_subsys_state *css = of_css(of);
4435 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4436 struct mem_cgroup_event *event;
4437 struct cgroup_subsys_state *cfile_css;
4438 unsigned int efd, cfd;
4445 buf = strstrip(buf);
4447 efd = simple_strtoul(buf, &endp, 10);
4452 cfd = simple_strtoul(buf, &endp, 10);
4453 if ((*endp != ' ') && (*endp != '\0'))
4457 event = kzalloc(sizeof(*event), GFP_KERNEL);
4461 event->memcg = memcg;
4462 INIT_LIST_HEAD(&event->list);
4463 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4464 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4465 INIT_WORK(&event->remove, memcg_event_remove);
4473 event->eventfd = eventfd_ctx_fileget(efile.file);
4474 if (IS_ERR(event->eventfd)) {
4475 ret = PTR_ERR(event->eventfd);
4482 goto out_put_eventfd;
4485 /* the process need read permission on control file */
4486 /* AV: shouldn't we check that it's been opened for read instead? */
4487 ret = inode_permission(file_inode(cfile.file), MAY_READ);
4492 * Determine the event callbacks and set them in @event. This used
4493 * to be done via struct cftype but cgroup core no longer knows
4494 * about these events. The following is crude but the whole thing
4495 * is for compatibility anyway.
4497 * DO NOT ADD NEW FILES.
4499 name = cfile.file->f_dentry->d_name.name;
4501 if (!strcmp(name, "memory.usage_in_bytes")) {
4502 event->register_event = mem_cgroup_usage_register_event;
4503 event->unregister_event = mem_cgroup_usage_unregister_event;
4504 } else if (!strcmp(name, "memory.oom_control")) {
4505 event->register_event = mem_cgroup_oom_register_event;
4506 event->unregister_event = mem_cgroup_oom_unregister_event;
4507 } else if (!strcmp(name, "memory.pressure_level")) {
4508 event->register_event = vmpressure_register_event;
4509 event->unregister_event = vmpressure_unregister_event;
4510 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4511 event->register_event = memsw_cgroup_usage_register_event;
4512 event->unregister_event = memsw_cgroup_usage_unregister_event;
4519 * Verify @cfile should belong to @css. Also, remaining events are
4520 * automatically removed on cgroup destruction but the removal is
4521 * asynchronous, so take an extra ref on @css.
4523 cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
4524 &memory_cgrp_subsys);
4526 if (IS_ERR(cfile_css))
4528 if (cfile_css != css) {
4533 ret = event->register_event(memcg, event->eventfd, buf);
4537 efile.file->f_op->poll(efile.file, &event->pt);
4539 spin_lock(&memcg->event_list_lock);
4540 list_add(&event->list, &memcg->event_list);
4541 spin_unlock(&memcg->event_list_lock);
4553 eventfd_ctx_put(event->eventfd);
4562 static struct cftype mem_cgroup_files[] = {
4564 .name = "usage_in_bytes",
4565 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4566 .read_u64 = mem_cgroup_read_u64,
4569 .name = "max_usage_in_bytes",
4570 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4571 .write = mem_cgroup_reset,
4572 .read_u64 = mem_cgroup_read_u64,
4575 .name = "limit_in_bytes",
4576 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4577 .write = mem_cgroup_write,
4578 .read_u64 = mem_cgroup_read_u64,
4581 .name = "soft_limit_in_bytes",
4582 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4583 .write = mem_cgroup_write,
4584 .read_u64 = mem_cgroup_read_u64,
4588 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4589 .write = mem_cgroup_reset,
4590 .read_u64 = mem_cgroup_read_u64,
4594 .seq_show = memcg_stat_show,
4597 .name = "force_empty",
4598 .write = mem_cgroup_force_empty_write,
4601 .name = "use_hierarchy",
4602 .write_u64 = mem_cgroup_hierarchy_write,
4603 .read_u64 = mem_cgroup_hierarchy_read,
4606 .name = "cgroup.event_control", /* XXX: for compat */
4607 .write = memcg_write_event_control,
4608 .flags = CFTYPE_NO_PREFIX,
4612 .name = "swappiness",
4613 .read_u64 = mem_cgroup_swappiness_read,
4614 .write_u64 = mem_cgroup_swappiness_write,
4617 .name = "move_charge_at_immigrate",
4618 .read_u64 = mem_cgroup_move_charge_read,
4619 .write_u64 = mem_cgroup_move_charge_write,
4622 .name = "oom_control",
4623 .seq_show = mem_cgroup_oom_control_read,
4624 .write_u64 = mem_cgroup_oom_control_write,
4625 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4628 .name = "pressure_level",
4632 .name = "numa_stat",
4633 .seq_show = memcg_numa_stat_show,
4636 #ifdef CONFIG_MEMCG_KMEM
4638 .name = "kmem.limit_in_bytes",
4639 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4640 .write = mem_cgroup_write,
4641 .read_u64 = mem_cgroup_read_u64,
4644 .name = "kmem.usage_in_bytes",
4645 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4646 .read_u64 = mem_cgroup_read_u64,
4649 .name = "kmem.failcnt",
4650 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4651 .write = mem_cgroup_reset,
4652 .read_u64 = mem_cgroup_read_u64,
4655 .name = "kmem.max_usage_in_bytes",
4656 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4657 .write = mem_cgroup_reset,
4658 .read_u64 = mem_cgroup_read_u64,
4660 #ifdef CONFIG_SLABINFO
4662 .name = "kmem.slabinfo",
4663 .seq_start = slab_start,
4664 .seq_next = slab_next,
4665 .seq_stop = slab_stop,
4666 .seq_show = memcg_slab_show,
4670 { }, /* terminate */
4673 #ifdef CONFIG_MEMCG_SWAP
4674 static struct cftype memsw_cgroup_files[] = {
4676 .name = "memsw.usage_in_bytes",
4677 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4678 .read_u64 = mem_cgroup_read_u64,
4681 .name = "memsw.max_usage_in_bytes",
4682 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4683 .write = mem_cgroup_reset,
4684 .read_u64 = mem_cgroup_read_u64,
4687 .name = "memsw.limit_in_bytes",
4688 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4689 .write = mem_cgroup_write,
4690 .read_u64 = mem_cgroup_read_u64,
4693 .name = "memsw.failcnt",
4694 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4695 .write = mem_cgroup_reset,
4696 .read_u64 = mem_cgroup_read_u64,
4698 { }, /* terminate */
4701 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4703 struct mem_cgroup_per_node *pn;
4704 struct mem_cgroup_per_zone *mz;
4705 int zone, tmp = node;
4707 * This routine is called against possible nodes.
4708 * But it's BUG to call kmalloc() against offline node.
4710 * TODO: this routine can waste much memory for nodes which will
4711 * never be onlined. It's better to use memory hotplug callback
4714 if (!node_state(node, N_NORMAL_MEMORY))
4716 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4720 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4721 mz = &pn->zoneinfo[zone];
4722 lruvec_init(&mz->lruvec);
4723 mz->usage_in_excess = 0;
4724 mz->on_tree = false;
4727 memcg->nodeinfo[node] = pn;
4731 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4733 kfree(memcg->nodeinfo[node]);
4736 static struct mem_cgroup *mem_cgroup_alloc(void)
4738 struct mem_cgroup *memcg;
4741 size = sizeof(struct mem_cgroup);
4742 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
4744 memcg = kzalloc(size, GFP_KERNEL);
4748 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4751 spin_lock_init(&memcg->pcp_counter_lock);
4760 * At destroying mem_cgroup, references from swap_cgroup can remain.
4761 * (scanning all at force_empty is too costly...)
4763 * Instead of clearing all references at force_empty, we remember
4764 * the number of reference from swap_cgroup and free mem_cgroup when
4765 * it goes down to 0.
4767 * Removal of cgroup itself succeeds regardless of refs from swap.
4770 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4774 mem_cgroup_remove_from_trees(memcg);
4777 free_mem_cgroup_per_zone_info(memcg, node);
4779 free_percpu(memcg->stat);
4782 * We need to make sure that (at least for now), the jump label
4783 * destruction code runs outside of the cgroup lock. This is because
4784 * get_online_cpus(), which is called from the static_branch update,
4785 * can't be called inside the cgroup_lock. cpusets are the ones
4786 * enforcing this dependency, so if they ever change, we might as well.
4788 * schedule_work() will guarantee this happens. Be careful if you need
4789 * to move this code around, and make sure it is outside
4792 disarm_static_keys(memcg);
4797 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4799 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
4801 if (!memcg->memory.parent)
4803 return mem_cgroup_from_counter(memcg->memory.parent, memory);
4805 EXPORT_SYMBOL(parent_mem_cgroup);
4807 static void __init mem_cgroup_soft_limit_tree_init(void)
4809 struct mem_cgroup_tree_per_node *rtpn;
4810 struct mem_cgroup_tree_per_zone *rtpz;
4811 int tmp, node, zone;
4813 for_each_node(node) {
4815 if (!node_state(node, N_NORMAL_MEMORY))
4817 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4820 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4822 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4823 rtpz = &rtpn->rb_tree_per_zone[zone];
4824 rtpz->rb_root = RB_ROOT;
4825 spin_lock_init(&rtpz->lock);
4830 static struct cgroup_subsys_state * __ref
4831 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
4833 struct mem_cgroup *memcg;
4834 long error = -ENOMEM;
4837 memcg = mem_cgroup_alloc();
4839 return ERR_PTR(error);
4842 if (alloc_mem_cgroup_per_zone_info(memcg, node))
4846 if (parent_css == NULL) {
4847 root_mem_cgroup = memcg;
4848 page_counter_init(&memcg->memory, NULL);
4849 page_counter_init(&memcg->memsw, NULL);
4850 page_counter_init(&memcg->kmem, NULL);
4853 memcg->last_scanned_node = MAX_NUMNODES;
4854 INIT_LIST_HEAD(&memcg->oom_notify);
4855 memcg->move_charge_at_immigrate = 0;
4856 mutex_init(&memcg->thresholds_lock);
4857 spin_lock_init(&memcg->move_lock);
4858 vmpressure_init(&memcg->vmpressure);
4859 INIT_LIST_HEAD(&memcg->event_list);
4860 spin_lock_init(&memcg->event_list_lock);
4865 __mem_cgroup_free(memcg);
4866 return ERR_PTR(error);
4870 mem_cgroup_css_online(struct cgroup_subsys_state *css)
4872 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4873 struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
4876 if (css->id > MEM_CGROUP_ID_MAX)
4882 mutex_lock(&memcg_create_mutex);
4884 memcg->use_hierarchy = parent->use_hierarchy;
4885 memcg->oom_kill_disable = parent->oom_kill_disable;
4886 memcg->swappiness = mem_cgroup_swappiness(parent);
4888 if (parent->use_hierarchy) {
4889 page_counter_init(&memcg->memory, &parent->memory);
4890 page_counter_init(&memcg->memsw, &parent->memsw);
4891 page_counter_init(&memcg->kmem, &parent->kmem);
4894 * No need to take a reference to the parent because cgroup
4895 * core guarantees its existence.
4898 page_counter_init(&memcg->memory, NULL);
4899 page_counter_init(&memcg->memsw, NULL);
4900 page_counter_init(&memcg->kmem, NULL);
4902 * Deeper hierachy with use_hierarchy == false doesn't make
4903 * much sense so let cgroup subsystem know about this
4904 * unfortunate state in our controller.
4906 if (parent != root_mem_cgroup)
4907 memory_cgrp_subsys.broken_hierarchy = true;
4909 mutex_unlock(&memcg_create_mutex);
4911 ret = memcg_init_kmem(memcg, &memory_cgrp_subsys);
4916 * Make sure the memcg is initialized: mem_cgroup_iter()
4917 * orders reading memcg->initialized against its callers
4918 * reading the memcg members.
4920 smp_store_release(&memcg->initialized, 1);
4925 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
4927 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4928 struct mem_cgroup_event *event, *tmp;
4931 * Unregister events and notify userspace.
4932 * Notify userspace about cgroup removing only after rmdir of cgroup
4933 * directory to avoid race between userspace and kernelspace.
4935 spin_lock(&memcg->event_list_lock);
4936 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
4937 list_del_init(&event->list);
4938 schedule_work(&event->remove);
4940 spin_unlock(&memcg->event_list_lock);
4942 memcg_unregister_all_caches(memcg);
4943 vmpressure_cleanup(&memcg->vmpressure);
4946 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
4948 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4950 memcg_destroy_kmem(memcg);
4951 __mem_cgroup_free(memcg);
4955 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4956 * @css: the target css
4958 * Reset the states of the mem_cgroup associated with @css. This is
4959 * invoked when the userland requests disabling on the default hierarchy
4960 * but the memcg is pinned through dependency. The memcg should stop
4961 * applying policies and should revert to the vanilla state as it may be
4962 * made visible again.
4964 * The current implementation only resets the essential configurations.
4965 * This needs to be expanded to cover all the visible parts.
4967 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
4969 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4971 mem_cgroup_resize_limit(memcg, PAGE_COUNTER_MAX);
4972 mem_cgroup_resize_memsw_limit(memcg, PAGE_COUNTER_MAX);
4973 memcg_update_kmem_limit(memcg, PAGE_COUNTER_MAX);
4974 memcg->soft_limit = 0;
4978 /* Handlers for move charge at task migration. */
4979 static int mem_cgroup_do_precharge(unsigned long count)
4983 /* Try a single bulk charge without reclaim first */
4984 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
4986 mc.precharge += count;
4989 if (ret == -EINTR) {
4990 cancel_charge(root_mem_cgroup, count);
4994 /* Try charges one by one with reclaim */
4996 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
4998 * In case of failure, any residual charges against
4999 * mc.to will be dropped by mem_cgroup_clear_mc()
5000 * later on. However, cancel any charges that are
5001 * bypassed to root right away or they'll be lost.
5004 cancel_charge(root_mem_cgroup, 1);
5014 * get_mctgt_type - get target type of moving charge
5015 * @vma: the vma the pte to be checked belongs
5016 * @addr: the address corresponding to the pte to be checked
5017 * @ptent: the pte to be checked
5018 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5021 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5022 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5023 * move charge. if @target is not NULL, the page is stored in target->page
5024 * with extra refcnt got(Callers should handle it).
5025 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5026 * target for charge migration. if @target is not NULL, the entry is stored
5029 * Called with pte lock held.
5036 enum mc_target_type {
5042 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5043 unsigned long addr, pte_t ptent)
5045 struct page *page = vm_normal_page(vma, addr, ptent);
5047 if (!page || !page_mapped(page))
5049 if (PageAnon(page)) {
5050 /* we don't move shared anon */
5053 } else if (!move_file())
5054 /* we ignore mapcount for file pages */
5056 if (!get_page_unless_zero(page))
5063 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5064 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5066 struct page *page = NULL;
5067 swp_entry_t ent = pte_to_swp_entry(ptent);
5069 if (!move_anon() || non_swap_entry(ent))
5072 * Because lookup_swap_cache() updates some statistics counter,
5073 * we call find_get_page() with swapper_space directly.
5075 page = find_get_page(swap_address_space(ent), ent.val);
5076 if (do_swap_account)
5077 entry->val = ent.val;
5082 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5083 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5089 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5090 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5092 struct page *page = NULL;
5093 struct address_space *mapping;
5096 if (!vma->vm_file) /* anonymous vma */
5101 mapping = vma->vm_file->f_mapping;
5102 if (pte_none(ptent))
5103 pgoff = linear_page_index(vma, addr);
5104 else /* pte_file(ptent) is true */
5105 pgoff = pte_to_pgoff(ptent);
5107 /* page is moved even if it's not RSS of this task(page-faulted). */
5109 /* shmem/tmpfs may report page out on swap: account for that too. */
5110 if (shmem_mapping(mapping)) {
5111 page = find_get_entry(mapping, pgoff);
5112 if (radix_tree_exceptional_entry(page)) {
5113 swp_entry_t swp = radix_to_swp_entry(page);
5114 if (do_swap_account)
5116 page = find_get_page(swap_address_space(swp), swp.val);
5119 page = find_get_page(mapping, pgoff);
5121 page = find_get_page(mapping, pgoff);
5126 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5127 unsigned long addr, pte_t ptent, union mc_target *target)
5129 struct page *page = NULL;
5130 struct page_cgroup *pc;
5131 enum mc_target_type ret = MC_TARGET_NONE;
5132 swp_entry_t ent = { .val = 0 };
5134 if (pte_present(ptent))
5135 page = mc_handle_present_pte(vma, addr, ptent);
5136 else if (is_swap_pte(ptent))
5137 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5138 else if (pte_none(ptent) || pte_file(ptent))
5139 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5141 if (!page && !ent.val)
5144 pc = lookup_page_cgroup(page);
5146 * Do only loose check w/o serialization.
5147 * mem_cgroup_move_account() checks the pc is valid or
5148 * not under LRU exclusion.
5150 if (pc->mem_cgroup == mc.from) {
5151 ret = MC_TARGET_PAGE;
5153 target->page = page;
5155 if (!ret || !target)
5158 /* There is a swap entry and a page doesn't exist or isn't charged */
5159 if (ent.val && !ret &&
5160 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5161 ret = MC_TARGET_SWAP;
5168 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5170 * We don't consider swapping or file mapped pages because THP does not
5171 * support them for now.
5172 * Caller should make sure that pmd_trans_huge(pmd) is true.
5174 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5175 unsigned long addr, pmd_t pmd, union mc_target *target)
5177 struct page *page = NULL;
5178 struct page_cgroup *pc;
5179 enum mc_target_type ret = MC_TARGET_NONE;
5181 page = pmd_page(pmd);
5182 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5185 pc = lookup_page_cgroup(page);
5186 if (pc->mem_cgroup == mc.from) {
5187 ret = MC_TARGET_PAGE;
5190 target->page = page;
5196 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5197 unsigned long addr, pmd_t pmd, union mc_target *target)
5199 return MC_TARGET_NONE;
5203 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5204 unsigned long addr, unsigned long end,
5205 struct mm_walk *walk)
5207 struct vm_area_struct *vma = walk->private;
5211 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
5212 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5213 mc.precharge += HPAGE_PMD_NR;
5218 if (pmd_trans_unstable(pmd))
5220 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5221 for (; addr != end; pte++, addr += PAGE_SIZE)
5222 if (get_mctgt_type(vma, addr, *pte, NULL))
5223 mc.precharge++; /* increment precharge temporarily */
5224 pte_unmap_unlock(pte - 1, ptl);
5230 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5232 unsigned long precharge;
5233 struct vm_area_struct *vma;
5235 down_read(&mm->mmap_sem);
5236 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5237 struct mm_walk mem_cgroup_count_precharge_walk = {
5238 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5242 if (is_vm_hugetlb_page(vma))
5244 walk_page_range(vma->vm_start, vma->vm_end,
5245 &mem_cgroup_count_precharge_walk);
5247 up_read(&mm->mmap_sem);
5249 precharge = mc.precharge;
5255 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5257 unsigned long precharge = mem_cgroup_count_precharge(mm);
5259 VM_BUG_ON(mc.moving_task);
5260 mc.moving_task = current;
5261 return mem_cgroup_do_precharge(precharge);
5264 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5265 static void __mem_cgroup_clear_mc(void)
5267 struct mem_cgroup *from = mc.from;
5268 struct mem_cgroup *to = mc.to;
5270 /* we must uncharge all the leftover precharges from mc.to */
5272 cancel_charge(mc.to, mc.precharge);
5276 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5277 * we must uncharge here.
5279 if (mc.moved_charge) {
5280 cancel_charge(mc.from, mc.moved_charge);
5281 mc.moved_charge = 0;
5283 /* we must fixup refcnts and charges */
5284 if (mc.moved_swap) {
5285 /* uncharge swap account from the old cgroup */
5286 if (!mem_cgroup_is_root(mc.from))
5287 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5290 * we charged both to->memory and to->memsw, so we
5291 * should uncharge to->memory.
5293 if (!mem_cgroup_is_root(mc.to))
5294 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5296 css_put_many(&mc.from->css, mc.moved_swap);
5298 /* we've already done css_get(mc.to) */
5301 memcg_oom_recover(from);
5302 memcg_oom_recover(to);
5303 wake_up_all(&mc.waitq);
5306 static void mem_cgroup_clear_mc(void)
5309 * we must clear moving_task before waking up waiters at the end of
5312 mc.moving_task = NULL;
5313 __mem_cgroup_clear_mc();
5314 spin_lock(&mc.lock);
5317 spin_unlock(&mc.lock);
5320 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
5321 struct cgroup_taskset *tset)
5323 struct task_struct *p = cgroup_taskset_first(tset);
5325 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5326 unsigned long move_charge_at_immigrate;
5329 * We are now commited to this value whatever it is. Changes in this
5330 * tunable will only affect upcoming migrations, not the current one.
5331 * So we need to save it, and keep it going.
5333 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
5334 if (move_charge_at_immigrate) {
5335 struct mm_struct *mm;
5336 struct mem_cgroup *from = mem_cgroup_from_task(p);
5338 VM_BUG_ON(from == memcg);
5340 mm = get_task_mm(p);
5343 /* We move charges only when we move a owner of the mm */
5344 if (mm->owner == p) {
5347 VM_BUG_ON(mc.precharge);
5348 VM_BUG_ON(mc.moved_charge);
5349 VM_BUG_ON(mc.moved_swap);
5351 spin_lock(&mc.lock);
5354 mc.immigrate_flags = move_charge_at_immigrate;
5355 spin_unlock(&mc.lock);
5356 /* We set mc.moving_task later */
5358 ret = mem_cgroup_precharge_mc(mm);
5360 mem_cgroup_clear_mc();
5367 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
5368 struct cgroup_taskset *tset)
5371 mem_cgroup_clear_mc();
5374 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5375 unsigned long addr, unsigned long end,
5376 struct mm_walk *walk)
5379 struct vm_area_struct *vma = walk->private;
5382 enum mc_target_type target_type;
5383 union mc_target target;
5385 struct page_cgroup *pc;
5388 * We don't take compound_lock() here but no race with splitting thp
5390 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5391 * under splitting, which means there's no concurrent thp split,
5392 * - if another thread runs into split_huge_page() just after we
5393 * entered this if-block, the thread must wait for page table lock
5394 * to be unlocked in __split_huge_page_splitting(), where the main
5395 * part of thp split is not executed yet.
5397 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
5398 if (mc.precharge < HPAGE_PMD_NR) {
5402 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5403 if (target_type == MC_TARGET_PAGE) {
5405 if (!isolate_lru_page(page)) {
5406 pc = lookup_page_cgroup(page);
5407 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
5408 pc, mc.from, mc.to)) {
5409 mc.precharge -= HPAGE_PMD_NR;
5410 mc.moved_charge += HPAGE_PMD_NR;
5412 putback_lru_page(page);
5420 if (pmd_trans_unstable(pmd))
5423 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5424 for (; addr != end; addr += PAGE_SIZE) {
5425 pte_t ptent = *(pte++);
5431 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5432 case MC_TARGET_PAGE:
5434 if (isolate_lru_page(page))
5436 pc = lookup_page_cgroup(page);
5437 if (!mem_cgroup_move_account(page, 1, pc,
5440 /* we uncharge from mc.from later. */
5443 putback_lru_page(page);
5444 put: /* get_mctgt_type() gets the page */
5447 case MC_TARGET_SWAP:
5449 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5451 /* we fixup refcnts and charges later. */
5459 pte_unmap_unlock(pte - 1, ptl);
5464 * We have consumed all precharges we got in can_attach().
5465 * We try charge one by one, but don't do any additional
5466 * charges to mc.to if we have failed in charge once in attach()
5469 ret = mem_cgroup_do_precharge(1);
5477 static void mem_cgroup_move_charge(struct mm_struct *mm)
5479 struct vm_area_struct *vma;
5481 lru_add_drain_all();
5483 * Signal mem_cgroup_begin_page_stat() to take the memcg's
5484 * move_lock while we're moving its pages to another memcg.
5485 * Then wait for already started RCU-only updates to finish.
5487 atomic_inc(&mc.from->moving_account);
5490 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5492 * Someone who are holding the mmap_sem might be waiting in
5493 * waitq. So we cancel all extra charges, wake up all waiters,
5494 * and retry. Because we cancel precharges, we might not be able
5495 * to move enough charges, but moving charge is a best-effort
5496 * feature anyway, so it wouldn't be a big problem.
5498 __mem_cgroup_clear_mc();
5502 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5504 struct mm_walk mem_cgroup_move_charge_walk = {
5505 .pmd_entry = mem_cgroup_move_charge_pte_range,
5509 if (is_vm_hugetlb_page(vma))
5511 ret = walk_page_range(vma->vm_start, vma->vm_end,
5512 &mem_cgroup_move_charge_walk);
5515 * means we have consumed all precharges and failed in
5516 * doing additional charge. Just abandon here.
5520 up_read(&mm->mmap_sem);
5521 atomic_dec(&mc.from->moving_account);
5524 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
5525 struct cgroup_taskset *tset)
5527 struct task_struct *p = cgroup_taskset_first(tset);
5528 struct mm_struct *mm = get_task_mm(p);
5532 mem_cgroup_move_charge(mm);
5536 mem_cgroup_clear_mc();
5538 #else /* !CONFIG_MMU */
5539 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
5540 struct cgroup_taskset *tset)
5544 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
5545 struct cgroup_taskset *tset)
5548 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
5549 struct cgroup_taskset *tset)
5555 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5556 * to verify whether we're attached to the default hierarchy on each mount
5559 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
5562 * use_hierarchy is forced on the default hierarchy. cgroup core
5563 * guarantees that @root doesn't have any children, so turning it
5564 * on for the root memcg is enough.
5566 if (cgroup_on_dfl(root_css->cgroup))
5567 mem_cgroup_from_css(root_css)->use_hierarchy = true;
5570 struct cgroup_subsys memory_cgrp_subsys = {
5571 .css_alloc = mem_cgroup_css_alloc,
5572 .css_online = mem_cgroup_css_online,
5573 .css_offline = mem_cgroup_css_offline,
5574 .css_free = mem_cgroup_css_free,
5575 .css_reset = mem_cgroup_css_reset,
5576 .can_attach = mem_cgroup_can_attach,
5577 .cancel_attach = mem_cgroup_cancel_attach,
5578 .attach = mem_cgroup_move_task,
5579 .bind = mem_cgroup_bind,
5580 .legacy_cftypes = mem_cgroup_files,
5584 #ifdef CONFIG_MEMCG_SWAP
5585 static int __init enable_swap_account(char *s)
5587 if (!strcmp(s, "1"))
5588 really_do_swap_account = 1;
5589 else if (!strcmp(s, "0"))
5590 really_do_swap_account = 0;
5593 __setup("swapaccount=", enable_swap_account);
5595 static void __init memsw_file_init(void)
5597 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
5598 memsw_cgroup_files));
5601 static void __init enable_swap_cgroup(void)
5603 if (!mem_cgroup_disabled() && really_do_swap_account) {
5604 do_swap_account = 1;
5610 static void __init enable_swap_cgroup(void)
5615 #ifdef CONFIG_MEMCG_SWAP
5617 * mem_cgroup_swapout - transfer a memsw charge to swap
5618 * @page: page whose memsw charge to transfer
5619 * @entry: swap entry to move the charge to
5621 * Transfer the memsw charge of @page to @entry.
5623 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
5625 struct mem_cgroup *memcg;
5626 struct page_cgroup *pc;
5627 unsigned short oldid;
5629 VM_BUG_ON_PAGE(PageLRU(page), page);
5630 VM_BUG_ON_PAGE(page_count(page), page);
5632 if (!do_swap_account)
5635 pc = lookup_page_cgroup(page);
5636 memcg = pc->mem_cgroup;
5638 /* Readahead page, never charged */
5642 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
5643 VM_BUG_ON_PAGE(oldid, page);
5644 mem_cgroup_swap_statistics(memcg, true);
5646 pc->mem_cgroup = NULL;
5648 if (!mem_cgroup_is_root(memcg))
5649 page_counter_uncharge(&memcg->memory, 1);
5651 /* XXX: caller holds IRQ-safe mapping->tree_lock */
5652 VM_BUG_ON(!irqs_disabled());
5654 mem_cgroup_charge_statistics(memcg, page, -1);
5655 memcg_check_events(memcg, page);
5659 * mem_cgroup_uncharge_swap - uncharge a swap entry
5660 * @entry: swap entry to uncharge
5662 * Drop the memsw charge associated with @entry.
5664 void mem_cgroup_uncharge_swap(swp_entry_t entry)
5666 struct mem_cgroup *memcg;
5669 if (!do_swap_account)
5672 id = swap_cgroup_record(entry, 0);
5674 memcg = mem_cgroup_lookup(id);
5676 if (!mem_cgroup_is_root(memcg))
5677 page_counter_uncharge(&memcg->memsw, 1);
5678 mem_cgroup_swap_statistics(memcg, false);
5679 css_put(&memcg->css);
5686 * mem_cgroup_try_charge - try charging a page
5687 * @page: page to charge
5688 * @mm: mm context of the victim
5689 * @gfp_mask: reclaim mode
5690 * @memcgp: charged memcg return
5692 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5693 * pages according to @gfp_mask if necessary.
5695 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5696 * Otherwise, an error code is returned.
5698 * After page->mapping has been set up, the caller must finalize the
5699 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5700 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5702 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
5703 gfp_t gfp_mask, struct mem_cgroup **memcgp)
5705 struct mem_cgroup *memcg = NULL;
5706 unsigned int nr_pages = 1;
5709 if (mem_cgroup_disabled())
5712 if (PageSwapCache(page)) {
5713 struct page_cgroup *pc = lookup_page_cgroup(page);
5715 * Every swap fault against a single page tries to charge the
5716 * page, bail as early as possible. shmem_unuse() encounters
5717 * already charged pages, too. The USED bit is protected by
5718 * the page lock, which serializes swap cache removal, which
5719 * in turn serializes uncharging.
5725 if (PageTransHuge(page)) {
5726 nr_pages <<= compound_order(page);
5727 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5730 if (do_swap_account && PageSwapCache(page))
5731 memcg = try_get_mem_cgroup_from_page(page);
5733 memcg = get_mem_cgroup_from_mm(mm);
5735 ret = try_charge(memcg, gfp_mask, nr_pages);
5737 css_put(&memcg->css);
5739 if (ret == -EINTR) {
5740 memcg = root_mem_cgroup;
5749 * mem_cgroup_commit_charge - commit a page charge
5750 * @page: page to charge
5751 * @memcg: memcg to charge the page to
5752 * @lrucare: page might be on LRU already
5754 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5755 * after page->mapping has been set up. This must happen atomically
5756 * as part of the page instantiation, i.e. under the page table lock
5757 * for anonymous pages, under the page lock for page and swap cache.
5759 * In addition, the page must not be on the LRU during the commit, to
5760 * prevent racing with task migration. If it might be, use @lrucare.
5762 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5764 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
5767 unsigned int nr_pages = 1;
5769 VM_BUG_ON_PAGE(!page->mapping, page);
5770 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
5772 if (mem_cgroup_disabled())
5775 * Swap faults will attempt to charge the same page multiple
5776 * times. But reuse_swap_page() might have removed the page
5777 * from swapcache already, so we can't check PageSwapCache().
5782 commit_charge(page, memcg, lrucare);
5784 if (PageTransHuge(page)) {
5785 nr_pages <<= compound_order(page);
5786 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5789 local_irq_disable();
5790 mem_cgroup_charge_statistics(memcg, page, nr_pages);
5791 memcg_check_events(memcg, page);
5794 if (do_swap_account && PageSwapCache(page)) {
5795 swp_entry_t entry = { .val = page_private(page) };
5797 * The swap entry might not get freed for a long time,
5798 * let's not wait for it. The page already received a
5799 * memory+swap charge, drop the swap entry duplicate.
5801 mem_cgroup_uncharge_swap(entry);
5806 * mem_cgroup_cancel_charge - cancel a page charge
5807 * @page: page to charge
5808 * @memcg: memcg to charge the page to
5810 * Cancel a charge transaction started by mem_cgroup_try_charge().
5812 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
5814 unsigned int nr_pages = 1;
5816 if (mem_cgroup_disabled())
5819 * Swap faults will attempt to charge the same page multiple
5820 * times. But reuse_swap_page() might have removed the page
5821 * from swapcache already, so we can't check PageSwapCache().
5826 if (PageTransHuge(page)) {
5827 nr_pages <<= compound_order(page);
5828 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5831 cancel_charge(memcg, nr_pages);
5834 static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
5835 unsigned long nr_anon, unsigned long nr_file,
5836 unsigned long nr_huge, struct page *dummy_page)
5838 unsigned long nr_pages = nr_anon + nr_file;
5839 unsigned long flags;
5841 if (!mem_cgroup_is_root(memcg)) {
5842 page_counter_uncharge(&memcg->memory, nr_pages);
5843 if (do_swap_account)
5844 page_counter_uncharge(&memcg->memsw, nr_pages);
5845 memcg_oom_recover(memcg);
5848 local_irq_save(flags);
5849 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
5850 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
5851 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
5852 __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
5853 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
5854 memcg_check_events(memcg, dummy_page);
5855 local_irq_restore(flags);
5857 if (!mem_cgroup_is_root(memcg))
5858 css_put_many(&memcg->css, nr_pages);
5861 static void uncharge_list(struct list_head *page_list)
5863 struct mem_cgroup *memcg = NULL;
5864 unsigned long nr_anon = 0;
5865 unsigned long nr_file = 0;
5866 unsigned long nr_huge = 0;
5867 unsigned long pgpgout = 0;
5868 struct list_head *next;
5871 next = page_list->next;
5873 unsigned int nr_pages = 1;
5874 struct page_cgroup *pc;
5876 page = list_entry(next, struct page, lru);
5877 next = page->lru.next;
5879 VM_BUG_ON_PAGE(PageLRU(page), page);
5880 VM_BUG_ON_PAGE(page_count(page), page);
5882 pc = lookup_page_cgroup(page);
5883 if (!pc->mem_cgroup)
5887 * Nobody should be changing or seriously looking at
5888 * pc->mem_cgroup at this point, we have fully
5889 * exclusive access to the page.
5892 if (memcg != pc->mem_cgroup) {
5894 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5896 pgpgout = nr_anon = nr_file = nr_huge = 0;
5898 memcg = pc->mem_cgroup;
5901 if (PageTransHuge(page)) {
5902 nr_pages <<= compound_order(page);
5903 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
5904 nr_huge += nr_pages;
5908 nr_anon += nr_pages;
5910 nr_file += nr_pages;
5912 pc->mem_cgroup = NULL;
5915 } while (next != page_list);
5918 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5923 * mem_cgroup_uncharge - uncharge a page
5924 * @page: page to uncharge
5926 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5927 * mem_cgroup_commit_charge().
5929 void mem_cgroup_uncharge(struct page *page)
5931 struct page_cgroup *pc;
5933 if (mem_cgroup_disabled())
5936 /* Don't touch page->lru of any random page, pre-check: */
5937 pc = lookup_page_cgroup(page);
5938 if (!pc->mem_cgroup)
5941 INIT_LIST_HEAD(&page->lru);
5942 uncharge_list(&page->lru);
5946 * mem_cgroup_uncharge_list - uncharge a list of page
5947 * @page_list: list of pages to uncharge
5949 * Uncharge a list of pages previously charged with
5950 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5952 void mem_cgroup_uncharge_list(struct list_head *page_list)
5954 if (mem_cgroup_disabled())
5957 if (!list_empty(page_list))
5958 uncharge_list(page_list);
5962 * mem_cgroup_migrate - migrate a charge to another page
5963 * @oldpage: currently charged page
5964 * @newpage: page to transfer the charge to
5965 * @lrucare: both pages might be on the LRU already
5967 * Migrate the charge from @oldpage to @newpage.
5969 * Both pages must be locked, @newpage->mapping must be set up.
5971 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
5974 struct mem_cgroup *memcg;
5975 struct page_cgroup *pc;
5978 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
5979 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
5980 VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
5981 VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
5982 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
5983 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
5986 if (mem_cgroup_disabled())
5989 /* Page cache replacement: new page already charged? */
5990 pc = lookup_page_cgroup(newpage);
5995 * Swapcache readahead pages can get migrated before being
5996 * charged, and migration from compaction can happen to an
5997 * uncharged page when the PFN walker finds a page that
5998 * reclaim just put back on the LRU but has not released yet.
6000 pc = lookup_page_cgroup(oldpage);
6001 memcg = pc->mem_cgroup;
6006 lock_page_lru(oldpage, &isolated);
6008 pc->mem_cgroup = NULL;
6011 unlock_page_lru(oldpage, isolated);
6013 commit_charge(newpage, memcg, lrucare);
6017 * subsys_initcall() for memory controller.
6019 * Some parts like hotcpu_notifier() have to be initialized from this context
6020 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6021 * everything that doesn't depend on a specific mem_cgroup structure should
6022 * be initialized from here.
6024 static int __init mem_cgroup_init(void)
6026 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6027 enable_swap_cgroup();
6028 mem_cgroup_soft_limit_tree_init();
6032 subsys_initcall(mem_cgroup_init);