1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
28 #include <linux/res_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
32 #include <linux/hugetlb.h>
33 #include <linux/pagemap.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/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 mem_cgroup_reclaim_iter {
148 * last scanned hierarchy member. Valid only if last_dead_count
149 * matches memcg->dead_count of the hierarchy root group.
151 struct mem_cgroup *last_visited;
154 /* scan generation, increased every round-trip */
155 unsigned int generation;
159 * per-zone information in memory controller.
161 struct mem_cgroup_per_zone {
162 struct lruvec lruvec;
163 unsigned long lru_size[NR_LRU_LISTS];
165 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
167 struct rb_node tree_node; /* RB tree node */
168 unsigned long long usage_in_excess;/* Set to the value by which */
169 /* the soft limit is exceeded*/
171 struct mem_cgroup *memcg; /* Back pointer, we cannot */
172 /* use container_of */
175 struct mem_cgroup_per_node {
176 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
180 * Cgroups above their limits are maintained in a RB-Tree, independent of
181 * their hierarchy representation
184 struct mem_cgroup_tree_per_zone {
185 struct rb_root rb_root;
189 struct mem_cgroup_tree_per_node {
190 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
193 struct mem_cgroup_tree {
194 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
197 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
199 struct mem_cgroup_threshold {
200 struct eventfd_ctx *eventfd;
205 struct mem_cgroup_threshold_ary {
206 /* An array index points to threshold just below or equal to usage. */
207 int current_threshold;
208 /* Size of entries[] */
210 /* Array of thresholds */
211 struct mem_cgroup_threshold entries[0];
214 struct mem_cgroup_thresholds {
215 /* Primary thresholds array */
216 struct mem_cgroup_threshold_ary *primary;
218 * Spare threshold array.
219 * This is needed to make mem_cgroup_unregister_event() "never fail".
220 * It must be able to store at least primary->size - 1 entries.
222 struct mem_cgroup_threshold_ary *spare;
226 struct mem_cgroup_eventfd_list {
227 struct list_head list;
228 struct eventfd_ctx *eventfd;
232 * cgroup_event represents events which userspace want to receive.
234 struct mem_cgroup_event {
236 * memcg which the event belongs to.
238 struct mem_cgroup *memcg;
240 * eventfd to signal userspace about the event.
242 struct eventfd_ctx *eventfd;
244 * Each of these stored in a list by the cgroup.
246 struct list_head list;
248 * register_event() callback will be used to add new userspace
249 * waiter for changes related to this event. Use eventfd_signal()
250 * on eventfd to send notification to userspace.
252 int (*register_event)(struct mem_cgroup *memcg,
253 struct eventfd_ctx *eventfd, const char *args);
255 * unregister_event() callback will be called when userspace closes
256 * the eventfd or on cgroup removing. This callback must be set,
257 * if you want provide notification functionality.
259 void (*unregister_event)(struct mem_cgroup *memcg,
260 struct eventfd_ctx *eventfd);
262 * All fields below needed to unregister event when
263 * userspace closes eventfd.
266 wait_queue_head_t *wqh;
268 struct work_struct remove;
271 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
272 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
275 * The memory controller data structure. The memory controller controls both
276 * page cache and RSS per cgroup. We would eventually like to provide
277 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
278 * to help the administrator determine what knobs to tune.
280 * TODO: Add a water mark for the memory controller. Reclaim will begin when
281 * we hit the water mark. May be even add a low water mark, such that
282 * no reclaim occurs from a cgroup at it's low water mark, this is
283 * a feature that will be implemented much later in the future.
286 struct cgroup_subsys_state css;
288 * the counter to account for memory usage
290 struct res_counter res;
292 /* vmpressure notifications */
293 struct vmpressure vmpressure;
295 /* css_online() has been completed */
299 * the counter to account for mem+swap usage.
301 struct res_counter memsw;
304 * the counter to account for kernel memory usage.
306 struct res_counter kmem;
308 * Should the accounting and control be hierarchical, per subtree?
311 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
315 atomic_t oom_wakeups;
318 /* OOM-Killer disable */
319 int oom_kill_disable;
321 /* set when res.limit == memsw.limit */
322 bool memsw_is_minimum;
324 /* protect arrays of thresholds */
325 struct mutex thresholds_lock;
327 /* thresholds for memory usage. RCU-protected */
328 struct mem_cgroup_thresholds thresholds;
330 /* thresholds for mem+swap usage. RCU-protected */
331 struct mem_cgroup_thresholds memsw_thresholds;
333 /* For oom notifier event fd */
334 struct list_head oom_notify;
337 * Should we move charges of a task when a task is moved into this
338 * mem_cgroup ? And what type of charges should we move ?
340 unsigned long move_charge_at_immigrate;
342 * set > 0 if pages under this cgroup are moving to other cgroup.
344 atomic_t moving_account;
345 /* taken only while moving_account > 0 */
346 spinlock_t move_lock;
350 struct mem_cgroup_stat_cpu __percpu *stat;
352 * used when a cpu is offlined or other synchronizations
353 * See mem_cgroup_read_stat().
355 struct mem_cgroup_stat_cpu nocpu_base;
356 spinlock_t pcp_counter_lock;
359 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
360 struct cg_proto tcp_mem;
362 #if defined(CONFIG_MEMCG_KMEM)
363 /* analogous to slab_common's slab_caches list, but per-memcg;
364 * protected by memcg_slab_mutex */
365 struct list_head memcg_slab_caches;
366 /* Index in the kmem_cache->memcg_params->memcg_caches array */
370 int last_scanned_node;
372 nodemask_t scan_nodes;
373 atomic_t numainfo_events;
374 atomic_t numainfo_updating;
377 /* List of events which userspace want to receive */
378 struct list_head event_list;
379 spinlock_t event_list_lock;
381 struct mem_cgroup_per_node *nodeinfo[0];
382 /* WARNING: nodeinfo must be the last member here */
385 /* internal only representation about the status of kmem accounting. */
387 KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */
388 KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
391 #ifdef CONFIG_MEMCG_KMEM
392 static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
394 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
397 static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
399 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
402 static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
405 * Our caller must use css_get() first, because memcg_uncharge_kmem()
406 * will call css_put() if it sees the memcg is dead.
409 if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
410 set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
413 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg)
415 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD,
416 &memcg->kmem_account_flags);
420 /* Stuffs for move charges at task migration. */
422 * Types of charges to be moved. "move_charge_at_immitgrate" and
423 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
426 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
427 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
431 /* "mc" and its members are protected by cgroup_mutex */
432 static struct move_charge_struct {
433 spinlock_t lock; /* for from, to */
434 struct mem_cgroup *from;
435 struct mem_cgroup *to;
436 unsigned long immigrate_flags;
437 unsigned long precharge;
438 unsigned long moved_charge;
439 unsigned long moved_swap;
440 struct task_struct *moving_task; /* a task moving charges */
441 wait_queue_head_t waitq; /* a waitq for other context */
443 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
444 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
447 static bool move_anon(void)
449 return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
452 static bool move_file(void)
454 return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
458 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
459 * limit reclaim to prevent infinite loops, if they ever occur.
461 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
462 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
465 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
466 MEM_CGROUP_CHARGE_TYPE_ANON,
467 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
468 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
472 /* for encoding cft->private value on file */
480 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
481 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
482 #define MEMFILE_ATTR(val) ((val) & 0xffff)
483 /* Used for OOM nofiier */
484 #define OOM_CONTROL (0)
487 * Reclaim flags for mem_cgroup_hierarchical_reclaim
489 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
490 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
491 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
492 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
495 * The memcg_create_mutex will be held whenever a new cgroup is created.
496 * As a consequence, any change that needs to protect against new child cgroups
497 * appearing has to hold it as well.
499 static DEFINE_MUTEX(memcg_create_mutex);
501 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
503 return s ? container_of(s, struct mem_cgroup, css) : NULL;
506 /* Some nice accessors for the vmpressure. */
507 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
510 memcg = root_mem_cgroup;
511 return &memcg->vmpressure;
514 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
516 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
519 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
521 return (memcg == root_mem_cgroup);
525 * We restrict the id in the range of [1, 65535], so it can fit into
528 #define MEM_CGROUP_ID_MAX USHRT_MAX
530 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
532 return memcg->css.id;
535 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
537 struct cgroup_subsys_state *css;
539 css = css_from_id(id, &memory_cgrp_subsys);
540 return mem_cgroup_from_css(css);
543 /* Writing them here to avoid exposing memcg's inner layout */
544 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
546 void sock_update_memcg(struct sock *sk)
548 if (mem_cgroup_sockets_enabled) {
549 struct mem_cgroup *memcg;
550 struct cg_proto *cg_proto;
552 BUG_ON(!sk->sk_prot->proto_cgroup);
554 /* Socket cloning can throw us here with sk_cgrp already
555 * filled. It won't however, necessarily happen from
556 * process context. So the test for root memcg given
557 * the current task's memcg won't help us in this case.
559 * Respecting the original socket's memcg is a better
560 * decision in this case.
563 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
564 css_get(&sk->sk_cgrp->memcg->css);
569 memcg = mem_cgroup_from_task(current);
570 cg_proto = sk->sk_prot->proto_cgroup(memcg);
571 if (!mem_cgroup_is_root(memcg) &&
572 memcg_proto_active(cg_proto) &&
573 css_tryget_online(&memcg->css)) {
574 sk->sk_cgrp = cg_proto;
579 EXPORT_SYMBOL(sock_update_memcg);
581 void sock_release_memcg(struct sock *sk)
583 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
584 struct mem_cgroup *memcg;
585 WARN_ON(!sk->sk_cgrp->memcg);
586 memcg = sk->sk_cgrp->memcg;
587 css_put(&sk->sk_cgrp->memcg->css);
591 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
593 if (!memcg || mem_cgroup_is_root(memcg))
596 return &memcg->tcp_mem;
598 EXPORT_SYMBOL(tcp_proto_cgroup);
600 static void disarm_sock_keys(struct mem_cgroup *memcg)
602 if (!memcg_proto_activated(&memcg->tcp_mem))
604 static_key_slow_dec(&memcg_socket_limit_enabled);
607 static void disarm_sock_keys(struct mem_cgroup *memcg)
612 #ifdef CONFIG_MEMCG_KMEM
614 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
615 * The main reason for not using cgroup id for this:
616 * this works better in sparse environments, where we have a lot of memcgs,
617 * but only a few kmem-limited. Or also, if we have, for instance, 200
618 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
619 * 200 entry array for that.
621 * The current size of the caches array is stored in
622 * memcg_limited_groups_array_size. It will double each time we have to
625 static DEFINE_IDA(kmem_limited_groups);
626 int memcg_limited_groups_array_size;
629 * MIN_SIZE is different than 1, because we would like to avoid going through
630 * the alloc/free process all the time. In a small machine, 4 kmem-limited
631 * cgroups is a reasonable guess. In the future, it could be a parameter or
632 * tunable, but that is strictly not necessary.
634 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
635 * this constant directly from cgroup, but it is understandable that this is
636 * better kept as an internal representation in cgroup.c. In any case, the
637 * cgrp_id space is not getting any smaller, and we don't have to necessarily
638 * increase ours as well if it increases.
640 #define MEMCG_CACHES_MIN_SIZE 4
641 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
644 * A lot of the calls to the cache allocation functions are expected to be
645 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
646 * conditional to this static branch, we'll have to allow modules that does
647 * kmem_cache_alloc and the such to see this symbol as well
649 struct static_key memcg_kmem_enabled_key;
650 EXPORT_SYMBOL(memcg_kmem_enabled_key);
652 static void disarm_kmem_keys(struct mem_cgroup *memcg)
654 if (memcg_kmem_is_active(memcg)) {
655 static_key_slow_dec(&memcg_kmem_enabled_key);
656 ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
659 * This check can't live in kmem destruction function,
660 * since the charges will outlive the cgroup
662 WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
665 static void disarm_kmem_keys(struct mem_cgroup *memcg)
668 #endif /* CONFIG_MEMCG_KMEM */
670 static void disarm_static_keys(struct mem_cgroup *memcg)
672 disarm_sock_keys(memcg);
673 disarm_kmem_keys(memcg);
676 static void drain_all_stock_async(struct mem_cgroup *memcg);
678 static struct mem_cgroup_per_zone *
679 mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
681 int nid = zone_to_nid(zone);
682 int zid = zone_idx(zone);
684 return &memcg->nodeinfo[nid]->zoneinfo[zid];
687 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
692 static struct mem_cgroup_per_zone *
693 mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
695 int nid = page_to_nid(page);
696 int zid = page_zonenum(page);
698 return &memcg->nodeinfo[nid]->zoneinfo[zid];
701 static struct mem_cgroup_tree_per_zone *
702 soft_limit_tree_node_zone(int nid, int zid)
704 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
707 static struct mem_cgroup_tree_per_zone *
708 soft_limit_tree_from_page(struct page *page)
710 int nid = page_to_nid(page);
711 int zid = page_zonenum(page);
713 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
716 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
717 struct mem_cgroup_tree_per_zone *mctz,
718 unsigned long long new_usage_in_excess)
720 struct rb_node **p = &mctz->rb_root.rb_node;
721 struct rb_node *parent = NULL;
722 struct mem_cgroup_per_zone *mz_node;
727 mz->usage_in_excess = new_usage_in_excess;
728 if (!mz->usage_in_excess)
732 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
734 if (mz->usage_in_excess < mz_node->usage_in_excess)
737 * We can't avoid mem cgroups that are over their soft
738 * limit by the same amount
740 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
743 rb_link_node(&mz->tree_node, parent, p);
744 rb_insert_color(&mz->tree_node, &mctz->rb_root);
748 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
749 struct mem_cgroup_tree_per_zone *mctz)
753 rb_erase(&mz->tree_node, &mctz->rb_root);
757 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
758 struct mem_cgroup_tree_per_zone *mctz)
762 spin_lock_irqsave(&mctz->lock, flags);
763 __mem_cgroup_remove_exceeded(mz, mctz);
764 spin_unlock_irqrestore(&mctz->lock, flags);
768 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
770 unsigned long long excess;
771 struct mem_cgroup_per_zone *mz;
772 struct mem_cgroup_tree_per_zone *mctz;
774 mctz = soft_limit_tree_from_page(page);
776 * Necessary to update all ancestors when hierarchy is used.
777 * because their event counter is not touched.
779 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
780 mz = mem_cgroup_page_zoneinfo(memcg, page);
781 excess = res_counter_soft_limit_excess(&memcg->res);
783 * We have to update the tree if mz is on RB-tree or
784 * mem is over its softlimit.
786 if (excess || mz->on_tree) {
789 spin_lock_irqsave(&mctz->lock, flags);
790 /* if on-tree, remove it */
792 __mem_cgroup_remove_exceeded(mz, mctz);
794 * Insert again. mz->usage_in_excess will be updated.
795 * If excess is 0, no tree ops.
797 __mem_cgroup_insert_exceeded(mz, mctz, excess);
798 spin_unlock_irqrestore(&mctz->lock, flags);
803 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
805 struct mem_cgroup_tree_per_zone *mctz;
806 struct mem_cgroup_per_zone *mz;
810 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
811 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
812 mctz = soft_limit_tree_node_zone(nid, zid);
813 mem_cgroup_remove_exceeded(mz, mctz);
818 static struct mem_cgroup_per_zone *
819 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
821 struct rb_node *rightmost = NULL;
822 struct mem_cgroup_per_zone *mz;
826 rightmost = rb_last(&mctz->rb_root);
828 goto done; /* Nothing to reclaim from */
830 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
832 * Remove the node now but someone else can add it back,
833 * we will to add it back at the end of reclaim to its correct
834 * position in the tree.
836 __mem_cgroup_remove_exceeded(mz, mctz);
837 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
838 !css_tryget_online(&mz->memcg->css))
844 static struct mem_cgroup_per_zone *
845 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
847 struct mem_cgroup_per_zone *mz;
849 spin_lock_irq(&mctz->lock);
850 mz = __mem_cgroup_largest_soft_limit_node(mctz);
851 spin_unlock_irq(&mctz->lock);
856 * Implementation Note: reading percpu statistics for memcg.
858 * Both of vmstat[] and percpu_counter has threshold and do periodic
859 * synchronization to implement "quick" read. There are trade-off between
860 * reading cost and precision of value. Then, we may have a chance to implement
861 * a periodic synchronizion of counter in memcg's counter.
863 * But this _read() function is used for user interface now. The user accounts
864 * memory usage by memory cgroup and he _always_ requires exact value because
865 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
866 * have to visit all online cpus and make sum. So, for now, unnecessary
867 * synchronization is not implemented. (just implemented for cpu hotplug)
869 * If there are kernel internal actions which can make use of some not-exact
870 * value, and reading all cpu value can be performance bottleneck in some
871 * common workload, threashold and synchonization as vmstat[] should be
874 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
875 enum mem_cgroup_stat_index idx)
881 for_each_online_cpu(cpu)
882 val += per_cpu(memcg->stat->count[idx], cpu);
883 #ifdef CONFIG_HOTPLUG_CPU
884 spin_lock(&memcg->pcp_counter_lock);
885 val += memcg->nocpu_base.count[idx];
886 spin_unlock(&memcg->pcp_counter_lock);
892 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
893 enum mem_cgroup_events_index idx)
895 unsigned long val = 0;
899 for_each_online_cpu(cpu)
900 val += per_cpu(memcg->stat->events[idx], cpu);
901 #ifdef CONFIG_HOTPLUG_CPU
902 spin_lock(&memcg->pcp_counter_lock);
903 val += memcg->nocpu_base.events[idx];
904 spin_unlock(&memcg->pcp_counter_lock);
910 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
915 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
916 * counted as CACHE even if it's on ANON LRU.
919 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
922 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
925 if (PageTransHuge(page))
926 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
929 /* pagein of a big page is an event. So, ignore page size */
931 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
933 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
934 nr_pages = -nr_pages; /* for event */
937 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
940 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
942 struct mem_cgroup_per_zone *mz;
944 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
945 return mz->lru_size[lru];
948 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
950 unsigned int lru_mask)
952 unsigned long nr = 0;
955 VM_BUG_ON((unsigned)nid >= nr_node_ids);
957 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
958 struct mem_cgroup_per_zone *mz;
962 if (!(BIT(lru) & lru_mask))
964 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
965 nr += mz->lru_size[lru];
971 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
972 unsigned int lru_mask)
974 unsigned long nr = 0;
977 for_each_node_state(nid, N_MEMORY)
978 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
982 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
983 enum mem_cgroup_events_target target)
985 unsigned long val, next;
987 val = __this_cpu_read(memcg->stat->nr_page_events);
988 next = __this_cpu_read(memcg->stat->targets[target]);
989 /* from time_after() in jiffies.h */
990 if ((long)next - (long)val < 0) {
992 case MEM_CGROUP_TARGET_THRESH:
993 next = val + THRESHOLDS_EVENTS_TARGET;
995 case MEM_CGROUP_TARGET_SOFTLIMIT:
996 next = val + SOFTLIMIT_EVENTS_TARGET;
998 case MEM_CGROUP_TARGET_NUMAINFO:
999 next = val + NUMAINFO_EVENTS_TARGET;
1004 __this_cpu_write(memcg->stat->targets[target], next);
1011 * Check events in order.
1014 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
1016 /* threshold event is triggered in finer grain than soft limit */
1017 if (unlikely(mem_cgroup_event_ratelimit(memcg,
1018 MEM_CGROUP_TARGET_THRESH))) {
1020 bool do_numainfo __maybe_unused;
1022 do_softlimit = mem_cgroup_event_ratelimit(memcg,
1023 MEM_CGROUP_TARGET_SOFTLIMIT);
1024 #if MAX_NUMNODES > 1
1025 do_numainfo = mem_cgroup_event_ratelimit(memcg,
1026 MEM_CGROUP_TARGET_NUMAINFO);
1028 mem_cgroup_threshold(memcg);
1029 if (unlikely(do_softlimit))
1030 mem_cgroup_update_tree(memcg, page);
1031 #if MAX_NUMNODES > 1
1032 if (unlikely(do_numainfo))
1033 atomic_inc(&memcg->numainfo_events);
1038 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1041 * mm_update_next_owner() may clear mm->owner to NULL
1042 * if it races with swapoff, page migration, etc.
1043 * So this can be called with p == NULL.
1048 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
1051 static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
1053 struct mem_cgroup *memcg = NULL;
1058 * Page cache insertions can happen withou an
1059 * actual mm context, e.g. during disk probing
1060 * on boot, loopback IO, acct() writes etc.
1063 memcg = root_mem_cgroup;
1065 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1066 if (unlikely(!memcg))
1067 memcg = root_mem_cgroup;
1069 } while (!css_tryget_online(&memcg->css));
1075 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1076 * ref. count) or NULL if the whole root's subtree has been visited.
1078 * helper function to be used by mem_cgroup_iter
1080 static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
1081 struct mem_cgroup *last_visited)
1083 struct cgroup_subsys_state *prev_css, *next_css;
1085 prev_css = last_visited ? &last_visited->css : NULL;
1087 next_css = css_next_descendant_pre(prev_css, &root->css);
1090 * Even if we found a group we have to make sure it is
1091 * alive. css && !memcg means that the groups should be
1092 * skipped and we should continue the tree walk.
1093 * last_visited css is safe to use because it is
1094 * protected by css_get and the tree walk is rcu safe.
1096 * We do not take a reference on the root of the tree walk
1097 * because we might race with the root removal when it would
1098 * be the only node in the iterated hierarchy and mem_cgroup_iter
1099 * would end up in an endless loop because it expects that at
1100 * least one valid node will be returned. Root cannot disappear
1101 * because caller of the iterator should hold it already so
1102 * skipping css reference should be safe.
1105 struct mem_cgroup *memcg = mem_cgroup_from_css(next_css);
1107 if (next_css == &root->css)
1110 if (css_tryget_online(next_css)) {
1112 * Make sure the memcg is initialized:
1113 * mem_cgroup_css_online() orders the the
1114 * initialization against setting the flag.
1116 if (smp_load_acquire(&memcg->initialized))
1121 prev_css = next_css;
1128 static void mem_cgroup_iter_invalidate(struct mem_cgroup *root)
1131 * When a group in the hierarchy below root is destroyed, the
1132 * hierarchy iterator can no longer be trusted since it might
1133 * have pointed to the destroyed group. Invalidate it.
1135 atomic_inc(&root->dead_count);
1138 static struct mem_cgroup *
1139 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
1140 struct mem_cgroup *root,
1143 struct mem_cgroup *position = NULL;
1145 * A cgroup destruction happens in two stages: offlining and
1146 * release. They are separated by a RCU grace period.
1148 * If the iterator is valid, we may still race with an
1149 * offlining. The RCU lock ensures the object won't be
1150 * released, tryget will fail if we lost the race.
1152 *sequence = atomic_read(&root->dead_count);
1153 if (iter->last_dead_count == *sequence) {
1155 position = iter->last_visited;
1158 * We cannot take a reference to root because we might race
1159 * with root removal and returning NULL would end up in
1160 * an endless loop on the iterator user level when root
1161 * would be returned all the time.
1163 if (position && position != root &&
1164 !css_tryget_online(&position->css))
1170 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
1171 struct mem_cgroup *last_visited,
1172 struct mem_cgroup *new_position,
1173 struct mem_cgroup *root,
1176 /* root reference counting symmetric to mem_cgroup_iter_load */
1177 if (last_visited && last_visited != root)
1178 css_put(&last_visited->css);
1180 * We store the sequence count from the time @last_visited was
1181 * loaded successfully instead of rereading it here so that we
1182 * don't lose destruction events in between. We could have
1183 * raced with the destruction of @new_position after all.
1185 iter->last_visited = new_position;
1187 iter->last_dead_count = sequence;
1191 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1192 * @root: hierarchy root
1193 * @prev: previously returned memcg, NULL on first invocation
1194 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1196 * Returns references to children of the hierarchy below @root, or
1197 * @root itself, or %NULL after a full round-trip.
1199 * Caller must pass the return value in @prev on subsequent
1200 * invocations for reference counting, or use mem_cgroup_iter_break()
1201 * to cancel a hierarchy walk before the round-trip is complete.
1203 * Reclaimers can specify a zone and a priority level in @reclaim to
1204 * divide up the memcgs in the hierarchy among all concurrent
1205 * reclaimers operating on the same zone and priority.
1207 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1208 struct mem_cgroup *prev,
1209 struct mem_cgroup_reclaim_cookie *reclaim)
1211 struct mem_cgroup *memcg = NULL;
1212 struct mem_cgroup *last_visited = NULL;
1214 if (mem_cgroup_disabled())
1218 root = root_mem_cgroup;
1220 if (prev && !reclaim)
1221 last_visited = prev;
1223 if (!root->use_hierarchy && root != root_mem_cgroup) {
1231 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1232 int uninitialized_var(seq);
1235 struct mem_cgroup_per_zone *mz;
1237 mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
1238 iter = &mz->reclaim_iter[reclaim->priority];
1239 if (prev && reclaim->generation != iter->generation) {
1240 iter->last_visited = NULL;
1244 last_visited = mem_cgroup_iter_load(iter, root, &seq);
1247 memcg = __mem_cgroup_iter_next(root, last_visited);
1250 mem_cgroup_iter_update(iter, last_visited, memcg, root,
1255 else if (!prev && memcg)
1256 reclaim->generation = iter->generation;
1265 if (prev && prev != root)
1266 css_put(&prev->css);
1272 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1273 * @root: hierarchy root
1274 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1276 void mem_cgroup_iter_break(struct mem_cgroup *root,
1277 struct mem_cgroup *prev)
1280 root = root_mem_cgroup;
1281 if (prev && prev != root)
1282 css_put(&prev->css);
1286 * Iteration constructs for visiting all cgroups (under a tree). If
1287 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1288 * be used for reference counting.
1290 #define for_each_mem_cgroup_tree(iter, root) \
1291 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1293 iter = mem_cgroup_iter(root, iter, NULL))
1295 #define for_each_mem_cgroup(iter) \
1296 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1298 iter = mem_cgroup_iter(NULL, iter, NULL))
1300 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1302 struct mem_cgroup *memcg;
1305 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1306 if (unlikely(!memcg))
1311 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1314 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1322 EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1325 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1326 * @zone: zone of the wanted lruvec
1327 * @memcg: memcg of the wanted lruvec
1329 * Returns the lru list vector holding pages for the given @zone and
1330 * @mem. This can be the global zone lruvec, if the memory controller
1333 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1334 struct mem_cgroup *memcg)
1336 struct mem_cgroup_per_zone *mz;
1337 struct lruvec *lruvec;
1339 if (mem_cgroup_disabled()) {
1340 lruvec = &zone->lruvec;
1344 mz = mem_cgroup_zone_zoneinfo(memcg, zone);
1345 lruvec = &mz->lruvec;
1348 * Since a node can be onlined after the mem_cgroup was created,
1349 * we have to be prepared to initialize lruvec->zone here;
1350 * and if offlined then reonlined, we need to reinitialize it.
1352 if (unlikely(lruvec->zone != zone))
1353 lruvec->zone = zone;
1358 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1360 * @zone: zone of the page
1362 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1364 struct mem_cgroup_per_zone *mz;
1365 struct mem_cgroup *memcg;
1366 struct page_cgroup *pc;
1367 struct lruvec *lruvec;
1369 if (mem_cgroup_disabled()) {
1370 lruvec = &zone->lruvec;
1374 pc = lookup_page_cgroup(page);
1375 memcg = pc->mem_cgroup;
1378 * Surreptitiously switch any uncharged offlist page to root:
1379 * an uncharged page off lru does nothing to secure
1380 * its former mem_cgroup from sudden removal.
1382 * Our caller holds lru_lock, and PageCgroupUsed is updated
1383 * under page_cgroup lock: between them, they make all uses
1384 * of pc->mem_cgroup safe.
1386 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1387 pc->mem_cgroup = memcg = root_mem_cgroup;
1389 mz = mem_cgroup_page_zoneinfo(memcg, page);
1390 lruvec = &mz->lruvec;
1393 * Since a node can be onlined after the mem_cgroup was created,
1394 * we have to be prepared to initialize lruvec->zone here;
1395 * and if offlined then reonlined, we need to reinitialize it.
1397 if (unlikely(lruvec->zone != zone))
1398 lruvec->zone = zone;
1403 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1404 * @lruvec: mem_cgroup per zone lru vector
1405 * @lru: index of lru list the page is sitting on
1406 * @nr_pages: positive when adding or negative when removing
1408 * This function must be called when a page is added to or removed from an
1411 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1414 struct mem_cgroup_per_zone *mz;
1415 unsigned long *lru_size;
1417 if (mem_cgroup_disabled())
1420 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1421 lru_size = mz->lru_size + lru;
1422 *lru_size += nr_pages;
1423 VM_BUG_ON((long)(*lru_size) < 0);
1427 * Checks whether given mem is same or in the root_mem_cgroup's
1430 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1431 struct mem_cgroup *memcg)
1433 if (root_memcg == memcg)
1435 if (!root_memcg->use_hierarchy || !memcg)
1437 return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup);
1440 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1441 struct mem_cgroup *memcg)
1446 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1451 bool task_in_mem_cgroup(struct task_struct *task,
1452 const struct mem_cgroup *memcg)
1454 struct mem_cgroup *curr = NULL;
1455 struct task_struct *p;
1458 p = find_lock_task_mm(task);
1460 curr = get_mem_cgroup_from_mm(p->mm);
1464 * All threads may have already detached their mm's, but the oom
1465 * killer still needs to detect if they have already been oom
1466 * killed to prevent needlessly killing additional tasks.
1469 curr = mem_cgroup_from_task(task);
1471 css_get(&curr->css);
1475 * We should check use_hierarchy of "memcg" not "curr". Because checking
1476 * use_hierarchy of "curr" here make this function true if hierarchy is
1477 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1478 * hierarchy(even if use_hierarchy is disabled in "memcg").
1480 ret = mem_cgroup_same_or_subtree(memcg, curr);
1481 css_put(&curr->css);
1485 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1487 unsigned long inactive_ratio;
1488 unsigned long inactive;
1489 unsigned long active;
1492 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1493 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1495 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1497 inactive_ratio = int_sqrt(10 * gb);
1501 return inactive * inactive_ratio < active;
1504 #define mem_cgroup_from_res_counter(counter, member) \
1505 container_of(counter, struct mem_cgroup, member)
1508 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1509 * @memcg: the memory cgroup
1511 * Returns the maximum amount of memory @mem can be charged with, in
1514 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1516 unsigned long long margin;
1518 margin = res_counter_margin(&memcg->res);
1519 if (do_swap_account)
1520 margin = min(margin, res_counter_margin(&memcg->memsw));
1521 return margin >> PAGE_SHIFT;
1524 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1527 if (mem_cgroup_disabled() || !memcg->css.parent)
1528 return vm_swappiness;
1530 return memcg->swappiness;
1534 * memcg->moving_account is used for checking possibility that some thread is
1535 * calling move_account(). When a thread on CPU-A starts moving pages under
1536 * a memcg, other threads should check memcg->moving_account under
1537 * rcu_read_lock(), like this:
1541 * memcg->moving_account+1 if (memcg->mocing_account)
1543 * synchronize_rcu() update something.
1548 /* for quick checking without looking up memcg */
1549 atomic_t memcg_moving __read_mostly;
1551 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1553 atomic_inc(&memcg_moving);
1554 atomic_inc(&memcg->moving_account);
1558 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1561 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1562 * We check NULL in callee rather than caller.
1565 atomic_dec(&memcg_moving);
1566 atomic_dec(&memcg->moving_account);
1571 * A routine for checking "mem" is under move_account() or not.
1573 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1574 * moving cgroups. This is for waiting at high-memory pressure
1577 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1579 struct mem_cgroup *from;
1580 struct mem_cgroup *to;
1583 * Unlike task_move routines, we access mc.to, mc.from not under
1584 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1586 spin_lock(&mc.lock);
1592 ret = mem_cgroup_same_or_subtree(memcg, from)
1593 || mem_cgroup_same_or_subtree(memcg, to);
1595 spin_unlock(&mc.lock);
1599 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1601 if (mc.moving_task && current != mc.moving_task) {
1602 if (mem_cgroup_under_move(memcg)) {
1604 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1605 /* moving charge context might have finished. */
1608 finish_wait(&mc.waitq, &wait);
1616 * Take this lock when
1617 * - a code tries to modify page's memcg while it's USED.
1618 * - a code tries to modify page state accounting in a memcg.
1620 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1621 unsigned long *flags)
1623 spin_lock_irqsave(&memcg->move_lock, *flags);
1626 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1627 unsigned long *flags)
1629 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1632 #define K(x) ((x) << (PAGE_SHIFT-10))
1634 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1635 * @memcg: The memory cgroup that went over limit
1636 * @p: Task that is going to be killed
1638 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1641 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1643 /* oom_info_lock ensures that parallel ooms do not interleave */
1644 static DEFINE_MUTEX(oom_info_lock);
1645 struct mem_cgroup *iter;
1651 mutex_lock(&oom_info_lock);
1654 pr_info("Task in ");
1655 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1656 pr_info(" killed as a result of limit of ");
1657 pr_cont_cgroup_path(memcg->css.cgroup);
1662 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1663 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1664 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1665 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1666 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1667 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1668 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1669 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1670 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1671 res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1672 res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1673 res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
1675 for_each_mem_cgroup_tree(iter, memcg) {
1676 pr_info("Memory cgroup stats for ");
1677 pr_cont_cgroup_path(iter->css.cgroup);
1680 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1681 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1683 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1684 K(mem_cgroup_read_stat(iter, i)));
1687 for (i = 0; i < NR_LRU_LISTS; i++)
1688 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1689 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1693 mutex_unlock(&oom_info_lock);
1697 * This function returns the number of memcg under hierarchy tree. Returns
1698 * 1(self count) if no children.
1700 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1703 struct mem_cgroup *iter;
1705 for_each_mem_cgroup_tree(iter, memcg)
1711 * Return the memory (and swap, if configured) limit for a memcg.
1713 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1717 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1720 * Do not consider swap space if we cannot swap due to swappiness
1722 if (mem_cgroup_swappiness(memcg)) {
1725 limit += total_swap_pages << PAGE_SHIFT;
1726 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1729 * If memsw is finite and limits the amount of swap space
1730 * available to this memcg, return that limit.
1732 limit = min(limit, memsw);
1738 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1741 struct mem_cgroup *iter;
1742 unsigned long chosen_points = 0;
1743 unsigned long totalpages;
1744 unsigned int points = 0;
1745 struct task_struct *chosen = NULL;
1748 * If current has a pending SIGKILL or is exiting, then automatically
1749 * select it. The goal is to allow it to allocate so that it may
1750 * quickly exit and free its memory.
1752 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1753 set_thread_flag(TIF_MEMDIE);
1757 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1758 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1759 for_each_mem_cgroup_tree(iter, memcg) {
1760 struct css_task_iter it;
1761 struct task_struct *task;
1763 css_task_iter_start(&iter->css, &it);
1764 while ((task = css_task_iter_next(&it))) {
1765 switch (oom_scan_process_thread(task, totalpages, NULL,
1767 case OOM_SCAN_SELECT:
1769 put_task_struct(chosen);
1771 chosen_points = ULONG_MAX;
1772 get_task_struct(chosen);
1774 case OOM_SCAN_CONTINUE:
1776 case OOM_SCAN_ABORT:
1777 css_task_iter_end(&it);
1778 mem_cgroup_iter_break(memcg, iter);
1780 put_task_struct(chosen);
1785 points = oom_badness(task, memcg, NULL, totalpages);
1786 if (!points || points < chosen_points)
1788 /* Prefer thread group leaders for display purposes */
1789 if (points == chosen_points &&
1790 thread_group_leader(chosen))
1794 put_task_struct(chosen);
1796 chosen_points = points;
1797 get_task_struct(chosen);
1799 css_task_iter_end(&it);
1804 points = chosen_points * 1000 / totalpages;
1805 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1806 NULL, "Memory cgroup out of memory");
1809 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1811 unsigned long flags)
1813 unsigned long total = 0;
1814 bool noswap = false;
1817 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1819 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1822 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1824 drain_all_stock_async(memcg);
1825 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1827 * Allow limit shrinkers, which are triggered directly
1828 * by userspace, to catch signals and stop reclaim
1829 * after minimal progress, regardless of the margin.
1831 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1833 if (mem_cgroup_margin(memcg))
1836 * If nothing was reclaimed after two attempts, there
1837 * may be no reclaimable pages in this hierarchy.
1846 * test_mem_cgroup_node_reclaimable
1847 * @memcg: the target memcg
1848 * @nid: the node ID to be checked.
1849 * @noswap : specify true here if the user wants flle only information.
1851 * This function returns whether the specified memcg contains any
1852 * reclaimable pages on a node. Returns true if there are any reclaimable
1853 * pages in the node.
1855 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1856 int nid, bool noswap)
1858 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1860 if (noswap || !total_swap_pages)
1862 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1867 #if MAX_NUMNODES > 1
1870 * Always updating the nodemask is not very good - even if we have an empty
1871 * list or the wrong list here, we can start from some node and traverse all
1872 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1875 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1879 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1880 * pagein/pageout changes since the last update.
1882 if (!atomic_read(&memcg->numainfo_events))
1884 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1887 /* make a nodemask where this memcg uses memory from */
1888 memcg->scan_nodes = node_states[N_MEMORY];
1890 for_each_node_mask(nid, node_states[N_MEMORY]) {
1892 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1893 node_clear(nid, memcg->scan_nodes);
1896 atomic_set(&memcg->numainfo_events, 0);
1897 atomic_set(&memcg->numainfo_updating, 0);
1901 * Selecting a node where we start reclaim from. Because what we need is just
1902 * reducing usage counter, start from anywhere is O,K. Considering
1903 * memory reclaim from current node, there are pros. and cons.
1905 * Freeing memory from current node means freeing memory from a node which
1906 * we'll use or we've used. So, it may make LRU bad. And if several threads
1907 * hit limits, it will see a contention on a node. But freeing from remote
1908 * node means more costs for memory reclaim because of memory latency.
1910 * Now, we use round-robin. Better algorithm is welcomed.
1912 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1916 mem_cgroup_may_update_nodemask(memcg);
1917 node = memcg->last_scanned_node;
1919 node = next_node(node, memcg->scan_nodes);
1920 if (node == MAX_NUMNODES)
1921 node = first_node(memcg->scan_nodes);
1923 * We call this when we hit limit, not when pages are added to LRU.
1924 * No LRU may hold pages because all pages are UNEVICTABLE or
1925 * memcg is too small and all pages are not on LRU. In that case,
1926 * we use curret node.
1928 if (unlikely(node == MAX_NUMNODES))
1929 node = numa_node_id();
1931 memcg->last_scanned_node = node;
1936 * Check all nodes whether it contains reclaimable pages or not.
1937 * For quick scan, we make use of scan_nodes. This will allow us to skip
1938 * unused nodes. But scan_nodes is lazily updated and may not cotain
1939 * enough new information. We need to do double check.
1941 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1946 * quick check...making use of scan_node.
1947 * We can skip unused nodes.
1949 if (!nodes_empty(memcg->scan_nodes)) {
1950 for (nid = first_node(memcg->scan_nodes);
1952 nid = next_node(nid, memcg->scan_nodes)) {
1954 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1959 * Check rest of nodes.
1961 for_each_node_state(nid, N_MEMORY) {
1962 if (node_isset(nid, memcg->scan_nodes))
1964 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1971 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1976 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1978 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1982 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1985 unsigned long *total_scanned)
1987 struct mem_cgroup *victim = NULL;
1990 unsigned long excess;
1991 unsigned long nr_scanned;
1992 struct mem_cgroup_reclaim_cookie reclaim = {
1997 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
2000 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
2005 * If we have not been able to reclaim
2006 * anything, it might because there are
2007 * no reclaimable pages under this hierarchy
2012 * We want to do more targeted reclaim.
2013 * excess >> 2 is not to excessive so as to
2014 * reclaim too much, nor too less that we keep
2015 * coming back to reclaim from this cgroup
2017 if (total >= (excess >> 2) ||
2018 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
2023 if (!mem_cgroup_reclaimable(victim, false))
2025 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
2027 *total_scanned += nr_scanned;
2028 if (!res_counter_soft_limit_excess(&root_memcg->res))
2031 mem_cgroup_iter_break(root_memcg, victim);
2035 #ifdef CONFIG_LOCKDEP
2036 static struct lockdep_map memcg_oom_lock_dep_map = {
2037 .name = "memcg_oom_lock",
2041 static DEFINE_SPINLOCK(memcg_oom_lock);
2044 * Check OOM-Killer is already running under our hierarchy.
2045 * If someone is running, return false.
2047 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
2049 struct mem_cgroup *iter, *failed = NULL;
2051 spin_lock(&memcg_oom_lock);
2053 for_each_mem_cgroup_tree(iter, memcg) {
2054 if (iter->oom_lock) {
2056 * this subtree of our hierarchy is already locked
2057 * so we cannot give a lock.
2060 mem_cgroup_iter_break(memcg, iter);
2063 iter->oom_lock = true;
2068 * OK, we failed to lock the whole subtree so we have
2069 * to clean up what we set up to the failing subtree
2071 for_each_mem_cgroup_tree(iter, memcg) {
2072 if (iter == failed) {
2073 mem_cgroup_iter_break(memcg, iter);
2076 iter->oom_lock = false;
2079 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
2081 spin_unlock(&memcg_oom_lock);
2086 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
2088 struct mem_cgroup *iter;
2090 spin_lock(&memcg_oom_lock);
2091 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
2092 for_each_mem_cgroup_tree(iter, memcg)
2093 iter->oom_lock = false;
2094 spin_unlock(&memcg_oom_lock);
2097 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
2099 struct mem_cgroup *iter;
2101 for_each_mem_cgroup_tree(iter, memcg)
2102 atomic_inc(&iter->under_oom);
2105 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
2107 struct mem_cgroup *iter;
2110 * When a new child is created while the hierarchy is under oom,
2111 * mem_cgroup_oom_lock() may not be called. We have to use
2112 * atomic_add_unless() here.
2114 for_each_mem_cgroup_tree(iter, memcg)
2115 atomic_add_unless(&iter->under_oom, -1, 0);
2118 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
2120 struct oom_wait_info {
2121 struct mem_cgroup *memcg;
2125 static int memcg_oom_wake_function(wait_queue_t *wait,
2126 unsigned mode, int sync, void *arg)
2128 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
2129 struct mem_cgroup *oom_wait_memcg;
2130 struct oom_wait_info *oom_wait_info;
2132 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
2133 oom_wait_memcg = oom_wait_info->memcg;
2136 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2137 * Then we can use css_is_ancestor without taking care of RCU.
2139 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
2140 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
2142 return autoremove_wake_function(wait, mode, sync, arg);
2145 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
2147 atomic_inc(&memcg->oom_wakeups);
2148 /* for filtering, pass "memcg" as argument. */
2149 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
2152 static void memcg_oom_recover(struct mem_cgroup *memcg)
2154 if (memcg && atomic_read(&memcg->under_oom))
2155 memcg_wakeup_oom(memcg);
2158 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
2160 if (!current->memcg_oom.may_oom)
2163 * We are in the middle of the charge context here, so we
2164 * don't want to block when potentially sitting on a callstack
2165 * that holds all kinds of filesystem and mm locks.
2167 * Also, the caller may handle a failed allocation gracefully
2168 * (like optional page cache readahead) and so an OOM killer
2169 * invocation might not even be necessary.
2171 * That's why we don't do anything here except remember the
2172 * OOM context and then deal with it at the end of the page
2173 * fault when the stack is unwound, the locks are released,
2174 * and when we know whether the fault was overall successful.
2176 css_get(&memcg->css);
2177 current->memcg_oom.memcg = memcg;
2178 current->memcg_oom.gfp_mask = mask;
2179 current->memcg_oom.order = order;
2183 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2184 * @handle: actually kill/wait or just clean up the OOM state
2186 * This has to be called at the end of a page fault if the memcg OOM
2187 * handler was enabled.
2189 * Memcg supports userspace OOM handling where failed allocations must
2190 * sleep on a waitqueue until the userspace task resolves the
2191 * situation. Sleeping directly in the charge context with all kinds
2192 * of locks held is not a good idea, instead we remember an OOM state
2193 * in the task and mem_cgroup_oom_synchronize() has to be called at
2194 * the end of the page fault to complete the OOM handling.
2196 * Returns %true if an ongoing memcg OOM situation was detected and
2197 * completed, %false otherwise.
2199 bool mem_cgroup_oom_synchronize(bool handle)
2201 struct mem_cgroup *memcg = current->memcg_oom.memcg;
2202 struct oom_wait_info owait;
2205 /* OOM is global, do not handle */
2212 owait.memcg = memcg;
2213 owait.wait.flags = 0;
2214 owait.wait.func = memcg_oom_wake_function;
2215 owait.wait.private = current;
2216 INIT_LIST_HEAD(&owait.wait.task_list);
2218 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
2219 mem_cgroup_mark_under_oom(memcg);
2221 locked = mem_cgroup_oom_trylock(memcg);
2224 mem_cgroup_oom_notify(memcg);
2226 if (locked && !memcg->oom_kill_disable) {
2227 mem_cgroup_unmark_under_oom(memcg);
2228 finish_wait(&memcg_oom_waitq, &owait.wait);
2229 mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
2230 current->memcg_oom.order);
2233 mem_cgroup_unmark_under_oom(memcg);
2234 finish_wait(&memcg_oom_waitq, &owait.wait);
2238 mem_cgroup_oom_unlock(memcg);
2240 * There is no guarantee that an OOM-lock contender
2241 * sees the wakeups triggered by the OOM kill
2242 * uncharges. Wake any sleepers explicitely.
2244 memcg_oom_recover(memcg);
2247 current->memcg_oom.memcg = NULL;
2248 css_put(&memcg->css);
2253 * Used to update mapped file or writeback or other statistics.
2255 * Notes: Race condition
2257 * Charging occurs during page instantiation, while the page is
2258 * unmapped and locked in page migration, or while the page table is
2259 * locked in THP migration. No race is possible.
2261 * Uncharge happens to pages with zero references, no race possible.
2263 * Charge moving between groups is protected by checking mm->moving
2264 * account and taking the move_lock in the slowpath.
2267 void __mem_cgroup_begin_update_page_stat(struct page *page,
2268 bool *locked, unsigned long *flags)
2270 struct mem_cgroup *memcg;
2271 struct page_cgroup *pc;
2273 pc = lookup_page_cgroup(page);
2275 memcg = pc->mem_cgroup;
2276 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2279 * If this memory cgroup is not under account moving, we don't
2280 * need to take move_lock_mem_cgroup(). Because we already hold
2281 * rcu_read_lock(), any calls to move_account will be delayed until
2282 * rcu_read_unlock().
2284 VM_BUG_ON(!rcu_read_lock_held());
2285 if (atomic_read(&memcg->moving_account) <= 0)
2288 move_lock_mem_cgroup(memcg, flags);
2289 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2290 move_unlock_mem_cgroup(memcg, flags);
2296 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2298 struct page_cgroup *pc = lookup_page_cgroup(page);
2301 * It's guaranteed that pc->mem_cgroup never changes while
2302 * lock is held because a routine modifies pc->mem_cgroup
2303 * should take move_lock_mem_cgroup().
2305 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2308 void mem_cgroup_update_page_stat(struct page *page,
2309 enum mem_cgroup_stat_index idx, int val)
2311 struct mem_cgroup *memcg;
2312 struct page_cgroup *pc = lookup_page_cgroup(page);
2313 unsigned long uninitialized_var(flags);
2315 if (mem_cgroup_disabled())
2318 VM_BUG_ON(!rcu_read_lock_held());
2319 memcg = pc->mem_cgroup;
2320 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2323 this_cpu_add(memcg->stat->count[idx], val);
2327 * size of first charge trial. "32" comes from vmscan.c's magic value.
2328 * TODO: maybe necessary to use big numbers in big irons.
2330 #define CHARGE_BATCH 32U
2331 struct memcg_stock_pcp {
2332 struct mem_cgroup *cached; /* this never be root cgroup */
2333 unsigned int nr_pages;
2334 struct work_struct work;
2335 unsigned long flags;
2336 #define FLUSHING_CACHED_CHARGE 0
2338 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2339 static DEFINE_MUTEX(percpu_charge_mutex);
2342 * consume_stock: Try to consume stocked charge on this cpu.
2343 * @memcg: memcg to consume from.
2344 * @nr_pages: how many pages to charge.
2346 * The charges will only happen if @memcg matches the current cpu's memcg
2347 * stock, and at least @nr_pages are available in that stock. Failure to
2348 * service an allocation will refill the stock.
2350 * returns true if successful, false otherwise.
2352 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2354 struct memcg_stock_pcp *stock;
2357 if (nr_pages > CHARGE_BATCH)
2360 stock = &get_cpu_var(memcg_stock);
2361 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2362 stock->nr_pages -= nr_pages;
2363 else /* need to call res_counter_charge */
2365 put_cpu_var(memcg_stock);
2370 * Returns stocks cached in percpu to res_counter and reset cached information.
2372 static void drain_stock(struct memcg_stock_pcp *stock)
2374 struct mem_cgroup *old = stock->cached;
2376 if (stock->nr_pages) {
2377 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2379 res_counter_uncharge(&old->res, bytes);
2380 if (do_swap_account)
2381 res_counter_uncharge(&old->memsw, bytes);
2382 stock->nr_pages = 0;
2384 stock->cached = NULL;
2388 * This must be called under preempt disabled or must be called by
2389 * a thread which is pinned to local cpu.
2391 static void drain_local_stock(struct work_struct *dummy)
2393 struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
2395 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2398 static void __init memcg_stock_init(void)
2402 for_each_possible_cpu(cpu) {
2403 struct memcg_stock_pcp *stock =
2404 &per_cpu(memcg_stock, cpu);
2405 INIT_WORK(&stock->work, drain_local_stock);
2410 * Cache charges(val) which is from res_counter, to local per_cpu area.
2411 * This will be consumed by consume_stock() function, later.
2413 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2415 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2417 if (stock->cached != memcg) { /* reset if necessary */
2419 stock->cached = memcg;
2421 stock->nr_pages += nr_pages;
2422 put_cpu_var(memcg_stock);
2426 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2427 * of the hierarchy under it. sync flag says whether we should block
2428 * until the work is done.
2430 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2434 /* Notify other cpus that system-wide "drain" is running */
2437 for_each_online_cpu(cpu) {
2438 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2439 struct mem_cgroup *memcg;
2441 memcg = stock->cached;
2442 if (!memcg || !stock->nr_pages)
2444 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2446 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2448 drain_local_stock(&stock->work);
2450 schedule_work_on(cpu, &stock->work);
2458 for_each_online_cpu(cpu) {
2459 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2460 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2461 flush_work(&stock->work);
2468 * Tries to drain stocked charges in other cpus. This function is asynchronous
2469 * and just put a work per cpu for draining localy on each cpu. Caller can
2470 * expects some charges will be back to res_counter later but cannot wait for
2473 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2476 * If someone calls draining, avoid adding more kworker runs.
2478 if (!mutex_trylock(&percpu_charge_mutex))
2480 drain_all_stock(root_memcg, false);
2481 mutex_unlock(&percpu_charge_mutex);
2484 /* This is a synchronous drain interface. */
2485 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2487 /* called when force_empty is called */
2488 mutex_lock(&percpu_charge_mutex);
2489 drain_all_stock(root_memcg, true);
2490 mutex_unlock(&percpu_charge_mutex);
2494 * This function drains percpu counter value from DEAD cpu and
2495 * move it to local cpu. Note that this function can be preempted.
2497 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2501 spin_lock(&memcg->pcp_counter_lock);
2502 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2503 long x = per_cpu(memcg->stat->count[i], cpu);
2505 per_cpu(memcg->stat->count[i], cpu) = 0;
2506 memcg->nocpu_base.count[i] += x;
2508 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2509 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2511 per_cpu(memcg->stat->events[i], cpu) = 0;
2512 memcg->nocpu_base.events[i] += x;
2514 spin_unlock(&memcg->pcp_counter_lock);
2517 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2518 unsigned long action,
2521 int cpu = (unsigned long)hcpu;
2522 struct memcg_stock_pcp *stock;
2523 struct mem_cgroup *iter;
2525 if (action == CPU_ONLINE)
2528 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2531 for_each_mem_cgroup(iter)
2532 mem_cgroup_drain_pcp_counter(iter, cpu);
2534 stock = &per_cpu(memcg_stock, cpu);
2539 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2540 unsigned int nr_pages)
2542 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2543 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2544 struct mem_cgroup *mem_over_limit;
2545 struct res_counter *fail_res;
2546 unsigned long nr_reclaimed;
2547 unsigned long flags = 0;
2548 unsigned long long size;
2551 if (mem_cgroup_is_root(memcg))
2554 if (consume_stock(memcg, nr_pages))
2557 size = batch * PAGE_SIZE;
2558 if (!res_counter_charge(&memcg->res, size, &fail_res)) {
2559 if (!do_swap_account)
2561 if (!res_counter_charge(&memcg->memsw, size, &fail_res))
2563 res_counter_uncharge(&memcg->res, size);
2564 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2565 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2567 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2569 if (batch > nr_pages) {
2575 * Unlike in global OOM situations, memcg is not in a physical
2576 * memory shortage. Allow dying and OOM-killed tasks to
2577 * bypass the last charges so that they can exit quickly and
2578 * free their memory.
2580 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
2581 fatal_signal_pending(current) ||
2582 current->flags & PF_EXITING))
2585 if (unlikely(task_in_memcg_oom(current)))
2588 if (!(gfp_mask & __GFP_WAIT))
2591 nr_reclaimed = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2593 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2596 if (gfp_mask & __GFP_NORETRY)
2599 * Even though the limit is exceeded at this point, reclaim
2600 * may have been able to free some pages. Retry the charge
2601 * before killing the task.
2603 * Only for regular pages, though: huge pages are rather
2604 * unlikely to succeed so close to the limit, and we fall back
2605 * to regular pages anyway in case of failure.
2607 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2610 * At task move, charge accounts can be doubly counted. So, it's
2611 * better to wait until the end of task_move if something is going on.
2613 if (mem_cgroup_wait_acct_move(mem_over_limit))
2619 if (gfp_mask & __GFP_NOFAIL)
2622 if (fatal_signal_pending(current))
2625 mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages));
2627 if (!(gfp_mask & __GFP_NOFAIL))
2633 if (batch > nr_pages)
2634 refill_stock(memcg, batch - nr_pages);
2639 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2641 unsigned long bytes = nr_pages * PAGE_SIZE;
2643 if (mem_cgroup_is_root(memcg))
2646 res_counter_uncharge(&memcg->res, bytes);
2647 if (do_swap_account)
2648 res_counter_uncharge(&memcg->memsw, bytes);
2652 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2653 * This is useful when moving usage to parent cgroup.
2655 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2656 unsigned int nr_pages)
2658 unsigned long bytes = nr_pages * PAGE_SIZE;
2660 if (mem_cgroup_is_root(memcg))
2663 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2664 if (do_swap_account)
2665 res_counter_uncharge_until(&memcg->memsw,
2666 memcg->memsw.parent, bytes);
2670 * A helper function to get mem_cgroup from ID. must be called under
2671 * rcu_read_lock(). The caller is responsible for calling
2672 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2673 * refcnt from swap can be called against removed memcg.)
2675 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2677 /* ID 0 is unused ID */
2680 return mem_cgroup_from_id(id);
2684 * try_get_mem_cgroup_from_page - look up page's memcg association
2687 * Look up, get a css reference, and return the memcg that owns @page.
2689 * The page must be locked to prevent racing with swap-in and page
2690 * cache charges. If coming from an unlocked page table, the caller
2691 * must ensure the page is on the LRU or this can race with charging.
2693 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2695 struct mem_cgroup *memcg = NULL;
2696 struct page_cgroup *pc;
2700 VM_BUG_ON_PAGE(!PageLocked(page), page);
2702 pc = lookup_page_cgroup(page);
2703 if (PageCgroupUsed(pc)) {
2704 memcg = pc->mem_cgroup;
2705 if (memcg && !css_tryget_online(&memcg->css))
2707 } else if (PageSwapCache(page)) {
2708 ent.val = page_private(page);
2709 id = lookup_swap_cgroup_id(ent);
2711 memcg = mem_cgroup_lookup(id);
2712 if (memcg && !css_tryget_online(&memcg->css))
2719 static void lock_page_lru(struct page *page, int *isolated)
2721 struct zone *zone = page_zone(page);
2723 spin_lock_irq(&zone->lru_lock);
2724 if (PageLRU(page)) {
2725 struct lruvec *lruvec;
2727 lruvec = mem_cgroup_page_lruvec(page, zone);
2729 del_page_from_lru_list(page, lruvec, page_lru(page));
2735 static void unlock_page_lru(struct page *page, int isolated)
2737 struct zone *zone = page_zone(page);
2740 struct lruvec *lruvec;
2742 lruvec = mem_cgroup_page_lruvec(page, zone);
2743 VM_BUG_ON_PAGE(PageLRU(page), page);
2745 add_page_to_lru_list(page, lruvec, page_lru(page));
2747 spin_unlock_irq(&zone->lru_lock);
2750 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2753 struct page_cgroup *pc = lookup_page_cgroup(page);
2756 VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
2758 * we don't need page_cgroup_lock about tail pages, becase they are not
2759 * accessed by any other context at this point.
2763 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2764 * may already be on some other mem_cgroup's LRU. Take care of it.
2767 lock_page_lru(page, &isolated);
2770 * Nobody should be changing or seriously looking at
2771 * pc->mem_cgroup and pc->flags at this point:
2773 * - the page is uncharged
2775 * - the page is off-LRU
2777 * - an anonymous fault has exclusive page access, except for
2778 * a locked page table
2780 * - a page cache insertion, a swapin fault, or a migration
2781 * have the page locked
2783 pc->mem_cgroup = memcg;
2784 pc->flags = PCG_USED | PCG_MEM | (do_swap_account ? PCG_MEMSW : 0);
2787 unlock_page_lru(page, isolated);
2790 static DEFINE_MUTEX(set_limit_mutex);
2792 #ifdef CONFIG_MEMCG_KMEM
2794 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2795 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2797 static DEFINE_MUTEX(memcg_slab_mutex);
2799 static DEFINE_MUTEX(activate_kmem_mutex);
2801 static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2803 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2804 memcg_kmem_is_active(memcg);
2808 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2809 * in the memcg_cache_params struct.
2811 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2813 struct kmem_cache *cachep;
2815 VM_BUG_ON(p->is_root_cache);
2816 cachep = p->root_cache;
2817 return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
2820 #ifdef CONFIG_SLABINFO
2821 static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v)
2823 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
2824 struct memcg_cache_params *params;
2826 if (!memcg_can_account_kmem(memcg))
2829 print_slabinfo_header(m);
2831 mutex_lock(&memcg_slab_mutex);
2832 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2833 cache_show(memcg_params_to_cache(params), m);
2834 mutex_unlock(&memcg_slab_mutex);
2840 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2842 struct res_counter *fail_res;
2845 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2849 ret = try_charge(memcg, gfp, size >> PAGE_SHIFT);
2850 if (ret == -EINTR) {
2852 * try_charge() chose to bypass to root due to OOM kill or
2853 * fatal signal. Since our only options are to either fail
2854 * the allocation or charge it to this cgroup, do it as a
2855 * temporary condition. But we can't fail. From a kmem/slab
2856 * perspective, the cache has already been selected, by
2857 * mem_cgroup_kmem_get_cache(), so it is too late to change
2860 * This condition will only trigger if the task entered
2861 * memcg_charge_kmem in a sane state, but was OOM-killed
2862 * during try_charge() above. Tasks that were already dying
2863 * when the allocation triggers should have been already
2864 * directed to the root cgroup in memcontrol.h
2866 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2867 if (do_swap_account)
2868 res_counter_charge_nofail(&memcg->memsw, size,
2872 res_counter_uncharge(&memcg->kmem, size);
2877 static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2879 res_counter_uncharge(&memcg->res, size);
2880 if (do_swap_account)
2881 res_counter_uncharge(&memcg->memsw, size);
2884 if (res_counter_uncharge(&memcg->kmem, size))
2888 * Releases a reference taken in kmem_cgroup_css_offline in case
2889 * this last uncharge is racing with the offlining code or it is
2890 * outliving the memcg existence.
2892 * The memory barrier imposed by test&clear is paired with the
2893 * explicit one in memcg_kmem_mark_dead().
2895 if (memcg_kmem_test_and_clear_dead(memcg))
2896 css_put(&memcg->css);
2900 * helper for acessing a memcg's index. It will be used as an index in the
2901 * child cache array in kmem_cache, and also to derive its name. This function
2902 * will return -1 when this is not a kmem-limited memcg.
2904 int memcg_cache_id(struct mem_cgroup *memcg)
2906 return memcg ? memcg->kmemcg_id : -1;
2909 static size_t memcg_caches_array_size(int num_groups)
2912 if (num_groups <= 0)
2915 size = 2 * num_groups;
2916 if (size < MEMCG_CACHES_MIN_SIZE)
2917 size = MEMCG_CACHES_MIN_SIZE;
2918 else if (size > MEMCG_CACHES_MAX_SIZE)
2919 size = MEMCG_CACHES_MAX_SIZE;
2925 * We should update the current array size iff all caches updates succeed. This
2926 * can only be done from the slab side. The slab mutex needs to be held when
2929 void memcg_update_array_size(int num)
2931 if (num > memcg_limited_groups_array_size)
2932 memcg_limited_groups_array_size = memcg_caches_array_size(num);
2935 int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
2937 struct memcg_cache_params *cur_params = s->memcg_params;
2939 VM_BUG_ON(!is_root_cache(s));
2941 if (num_groups > memcg_limited_groups_array_size) {
2943 struct memcg_cache_params *new_params;
2944 ssize_t size = memcg_caches_array_size(num_groups);
2946 size *= sizeof(void *);
2947 size += offsetof(struct memcg_cache_params, memcg_caches);
2949 new_params = kzalloc(size, GFP_KERNEL);
2953 new_params->is_root_cache = true;
2956 * There is the chance it will be bigger than
2957 * memcg_limited_groups_array_size, if we failed an allocation
2958 * in a cache, in which case all caches updated before it, will
2959 * have a bigger array.
2961 * But if that is the case, the data after
2962 * memcg_limited_groups_array_size is certainly unused
2964 for (i = 0; i < memcg_limited_groups_array_size; i++) {
2965 if (!cur_params->memcg_caches[i])
2967 new_params->memcg_caches[i] =
2968 cur_params->memcg_caches[i];
2972 * Ideally, we would wait until all caches succeed, and only
2973 * then free the old one. But this is not worth the extra
2974 * pointer per-cache we'd have to have for this.
2976 * It is not a big deal if some caches are left with a size
2977 * bigger than the others. And all updates will reset this
2980 rcu_assign_pointer(s->memcg_params, new_params);
2982 kfree_rcu(cur_params, rcu_head);
2987 int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
2988 struct kmem_cache *root_cache)
2992 if (!memcg_kmem_enabled())
2996 size = offsetof(struct memcg_cache_params, memcg_caches);
2997 size += memcg_limited_groups_array_size * sizeof(void *);
2999 size = sizeof(struct memcg_cache_params);
3001 s->memcg_params = kzalloc(size, GFP_KERNEL);
3002 if (!s->memcg_params)
3006 s->memcg_params->memcg = memcg;
3007 s->memcg_params->root_cache = root_cache;
3008 css_get(&memcg->css);
3010 s->memcg_params->is_root_cache = true;
3015 void memcg_free_cache_params(struct kmem_cache *s)
3017 if (!s->memcg_params)
3019 if (!s->memcg_params->is_root_cache)
3020 css_put(&s->memcg_params->memcg->css);
3021 kfree(s->memcg_params);
3024 static void memcg_register_cache(struct mem_cgroup *memcg,
3025 struct kmem_cache *root_cache)
3027 static char memcg_name_buf[NAME_MAX + 1]; /* protected by
3029 struct kmem_cache *cachep;
3032 lockdep_assert_held(&memcg_slab_mutex);
3034 id = memcg_cache_id(memcg);
3037 * Since per-memcg caches are created asynchronously on first
3038 * allocation (see memcg_kmem_get_cache()), several threads can try to
3039 * create the same cache, but only one of them may succeed.
3041 if (cache_from_memcg_idx(root_cache, id))
3044 cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
3045 cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
3047 * If we could not create a memcg cache, do not complain, because
3048 * that's not critical at all as we can always proceed with the root
3054 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
3057 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3058 * barrier here to ensure nobody will see the kmem_cache partially
3063 BUG_ON(root_cache->memcg_params->memcg_caches[id]);
3064 root_cache->memcg_params->memcg_caches[id] = cachep;
3067 static void memcg_unregister_cache(struct kmem_cache *cachep)
3069 struct kmem_cache *root_cache;
3070 struct mem_cgroup *memcg;
3073 lockdep_assert_held(&memcg_slab_mutex);
3075 BUG_ON(is_root_cache(cachep));
3077 root_cache = cachep->memcg_params->root_cache;
3078 memcg = cachep->memcg_params->memcg;
3079 id = memcg_cache_id(memcg);
3081 BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
3082 root_cache->memcg_params->memcg_caches[id] = NULL;
3084 list_del(&cachep->memcg_params->list);
3086 kmem_cache_destroy(cachep);
3090 * During the creation a new cache, we need to disable our accounting mechanism
3091 * altogether. This is true even if we are not creating, but rather just
3092 * enqueing new caches to be created.
3094 * This is because that process will trigger allocations; some visible, like
3095 * explicit kmallocs to auxiliary data structures, name strings and internal
3096 * cache structures; some well concealed, like INIT_WORK() that can allocate
3097 * objects during debug.
3099 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3100 * to it. This may not be a bounded recursion: since the first cache creation
3101 * failed to complete (waiting on the allocation), we'll just try to create the
3102 * cache again, failing at the same point.
3104 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3105 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3106 * inside the following two functions.
3108 static inline void memcg_stop_kmem_account(void)
3110 VM_BUG_ON(!current->mm);
3111 current->memcg_kmem_skip_account++;
3114 static inline void memcg_resume_kmem_account(void)
3116 VM_BUG_ON(!current->mm);
3117 current->memcg_kmem_skip_account--;
3120 int __memcg_cleanup_cache_params(struct kmem_cache *s)
3122 struct kmem_cache *c;
3125 mutex_lock(&memcg_slab_mutex);
3126 for_each_memcg_cache_index(i) {
3127 c = cache_from_memcg_idx(s, i);
3131 memcg_unregister_cache(c);
3133 if (cache_from_memcg_idx(s, i))
3136 mutex_unlock(&memcg_slab_mutex);
3140 static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
3142 struct kmem_cache *cachep;
3143 struct memcg_cache_params *params, *tmp;
3145 if (!memcg_kmem_is_active(memcg))
3148 mutex_lock(&memcg_slab_mutex);
3149 list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
3150 cachep = memcg_params_to_cache(params);
3151 kmem_cache_shrink(cachep);
3152 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
3153 memcg_unregister_cache(cachep);
3155 mutex_unlock(&memcg_slab_mutex);
3158 struct memcg_register_cache_work {
3159 struct mem_cgroup *memcg;
3160 struct kmem_cache *cachep;
3161 struct work_struct work;
3164 static void memcg_register_cache_func(struct work_struct *w)
3166 struct memcg_register_cache_work *cw =
3167 container_of(w, struct memcg_register_cache_work, work);
3168 struct mem_cgroup *memcg = cw->memcg;
3169 struct kmem_cache *cachep = cw->cachep;
3171 mutex_lock(&memcg_slab_mutex);
3172 memcg_register_cache(memcg, cachep);
3173 mutex_unlock(&memcg_slab_mutex);
3175 css_put(&memcg->css);
3180 * Enqueue the creation of a per-memcg kmem_cache.
3182 static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
3183 struct kmem_cache *cachep)
3185 struct memcg_register_cache_work *cw;
3187 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
3189 css_put(&memcg->css);
3194 cw->cachep = cachep;
3196 INIT_WORK(&cw->work, memcg_register_cache_func);
3197 schedule_work(&cw->work);
3200 static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
3201 struct kmem_cache *cachep)
3204 * We need to stop accounting when we kmalloc, because if the
3205 * corresponding kmalloc cache is not yet created, the first allocation
3206 * in __memcg_schedule_register_cache will recurse.
3208 * However, it is better to enclose the whole function. Depending on
3209 * the debugging options enabled, INIT_WORK(), for instance, can
3210 * trigger an allocation. This too, will make us recurse. Because at
3211 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3212 * the safest choice is to do it like this, wrapping the whole function.
3214 memcg_stop_kmem_account();
3215 __memcg_schedule_register_cache(memcg, cachep);
3216 memcg_resume_kmem_account();
3219 int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
3223 res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp,
3224 PAGE_SIZE << order);
3226 atomic_add(1 << order, &cachep->memcg_params->nr_pages);
3230 void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
3232 memcg_uncharge_kmem(cachep->memcg_params->memcg, PAGE_SIZE << order);
3233 atomic_sub(1 << order, &cachep->memcg_params->nr_pages);
3237 * Return the kmem_cache we're supposed to use for a slab allocation.
3238 * We try to use the current memcg's version of the cache.
3240 * If the cache does not exist yet, if we are the first user of it,
3241 * we either create it immediately, if possible, or create it asynchronously
3243 * In the latter case, we will let the current allocation go through with
3244 * the original cache.
3246 * Can't be called in interrupt context or from kernel threads.
3247 * This function needs to be called with rcu_read_lock() held.
3249 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3252 struct mem_cgroup *memcg;
3253 struct kmem_cache *memcg_cachep;
3255 VM_BUG_ON(!cachep->memcg_params);
3256 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3258 if (!current->mm || current->memcg_kmem_skip_account)
3262 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3264 if (!memcg_can_account_kmem(memcg))
3267 memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
3268 if (likely(memcg_cachep)) {
3269 cachep = memcg_cachep;
3273 /* The corresponding put will be done in the workqueue. */
3274 if (!css_tryget_online(&memcg->css))
3279 * If we are in a safe context (can wait, and not in interrupt
3280 * context), we could be be predictable and return right away.
3281 * This would guarantee that the allocation being performed
3282 * already belongs in the new cache.
3284 * However, there are some clashes that can arrive from locking.
3285 * For instance, because we acquire the slab_mutex while doing
3286 * memcg_create_kmem_cache, this means no further allocation
3287 * could happen with the slab_mutex held. So it's better to
3290 memcg_schedule_register_cache(memcg, cachep);
3298 * We need to verify if the allocation against current->mm->owner's memcg is
3299 * possible for the given order. But the page is not allocated yet, so we'll
3300 * need a further commit step to do the final arrangements.
3302 * It is possible for the task to switch cgroups in this mean time, so at
3303 * commit time, we can't rely on task conversion any longer. We'll then use
3304 * the handle argument to return to the caller which cgroup we should commit
3305 * against. We could also return the memcg directly and avoid the pointer
3306 * passing, but a boolean return value gives better semantics considering
3307 * the compiled-out case as well.
3309 * Returning true means the allocation is possible.
3312 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3314 struct mem_cgroup *memcg;
3320 * Disabling accounting is only relevant for some specific memcg
3321 * internal allocations. Therefore we would initially not have such
3322 * check here, since direct calls to the page allocator that are
3323 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
3324 * outside memcg core. We are mostly concerned with cache allocations,
3325 * and by having this test at memcg_kmem_get_cache, we are already able
3326 * to relay the allocation to the root cache and bypass the memcg cache
3329 * There is one exception, though: the SLUB allocator does not create
3330 * large order caches, but rather service large kmallocs directly from
3331 * the page allocator. Therefore, the following sequence when backed by
3332 * the SLUB allocator:
3334 * memcg_stop_kmem_account();
3335 * kmalloc(<large_number>)
3336 * memcg_resume_kmem_account();
3338 * would effectively ignore the fact that we should skip accounting,
3339 * since it will drive us directly to this function without passing
3340 * through the cache selector memcg_kmem_get_cache. Such large
3341 * allocations are extremely rare but can happen, for instance, for the
3342 * cache arrays. We bring this test here.
3344 if (!current->mm || current->memcg_kmem_skip_account)
3347 memcg = get_mem_cgroup_from_mm(current->mm);
3349 if (!memcg_can_account_kmem(memcg)) {
3350 css_put(&memcg->css);
3354 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3358 css_put(&memcg->css);
3362 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3365 struct page_cgroup *pc;
3367 VM_BUG_ON(mem_cgroup_is_root(memcg));
3369 /* The page allocation failed. Revert */
3371 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3375 * The page is freshly allocated and not visible to any
3376 * outside callers yet. Set up pc non-atomically.
3378 pc = lookup_page_cgroup(page);
3379 pc->mem_cgroup = memcg;
3380 pc->flags = PCG_USED;
3383 void __memcg_kmem_uncharge_pages(struct page *page, int order)
3385 struct mem_cgroup *memcg = NULL;
3386 struct page_cgroup *pc;
3389 pc = lookup_page_cgroup(page);
3390 if (!PageCgroupUsed(pc))
3393 memcg = pc->mem_cgroup;
3397 * We trust that only if there is a memcg associated with the page, it
3398 * is a valid allocation
3403 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
3404 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3407 static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
3410 #endif /* CONFIG_MEMCG_KMEM */
3412 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3415 * Because tail pages are not marked as "used", set it. We're under
3416 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3417 * charge/uncharge will be never happen and move_account() is done under
3418 * compound_lock(), so we don't have to take care of races.
3420 void mem_cgroup_split_huge_fixup(struct page *head)
3422 struct page_cgroup *head_pc = lookup_page_cgroup(head);
3423 struct page_cgroup *pc;
3424 struct mem_cgroup *memcg;
3427 if (mem_cgroup_disabled())
3430 memcg = head_pc->mem_cgroup;
3431 for (i = 1; i < HPAGE_PMD_NR; i++) {
3433 pc->mem_cgroup = memcg;
3434 pc->flags = head_pc->flags;
3436 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3439 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3442 * mem_cgroup_move_account - move account of the page
3444 * @nr_pages: number of regular pages (>1 for huge pages)
3445 * @pc: page_cgroup of the page.
3446 * @from: mem_cgroup which the page is moved from.
3447 * @to: mem_cgroup which the page is moved to. @from != @to.
3449 * The caller must confirm following.
3450 * - page is not on LRU (isolate_page() is useful.)
3451 * - compound_lock is held when nr_pages > 1
3453 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3456 static int mem_cgroup_move_account(struct page *page,
3457 unsigned int nr_pages,
3458 struct page_cgroup *pc,
3459 struct mem_cgroup *from,
3460 struct mem_cgroup *to)
3462 unsigned long flags;
3465 VM_BUG_ON(from == to);
3466 VM_BUG_ON_PAGE(PageLRU(page), page);
3468 * The page is isolated from LRU. So, collapse function
3469 * will not handle this page. But page splitting can happen.
3470 * Do this check under compound_page_lock(). The caller should
3474 if (nr_pages > 1 && !PageTransHuge(page))
3478 * Prevent mem_cgroup_migrate() from looking at pc->mem_cgroup
3479 * of its source page while we change it: page migration takes
3480 * both pages off the LRU, but page cache replacement doesn't.
3482 if (!trylock_page(page))
3486 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3489 move_lock_mem_cgroup(from, &flags);
3491 if (!PageAnon(page) && page_mapped(page)) {
3492 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3494 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3498 if (PageWriteback(page)) {
3499 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3501 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3506 * It is safe to change pc->mem_cgroup here because the page
3507 * is referenced, charged, and isolated - we can't race with
3508 * uncharging, charging, migration, or LRU putback.
3511 /* caller should have done css_get */
3512 pc->mem_cgroup = to;
3513 move_unlock_mem_cgroup(from, &flags);
3516 local_irq_disable();
3517 mem_cgroup_charge_statistics(to, page, nr_pages);
3518 memcg_check_events(to, page);
3519 mem_cgroup_charge_statistics(from, page, -nr_pages);
3520 memcg_check_events(from, page);
3529 * mem_cgroup_move_parent - moves page to the parent group
3530 * @page: the page to move
3531 * @pc: page_cgroup of the page
3532 * @child: page's cgroup
3534 * move charges to its parent or the root cgroup if the group has no
3535 * parent (aka use_hierarchy==0).
3536 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3537 * mem_cgroup_move_account fails) the failure is always temporary and
3538 * it signals a race with a page removal/uncharge or migration. In the
3539 * first case the page is on the way out and it will vanish from the LRU
3540 * on the next attempt and the call should be retried later.
3541 * Isolation from the LRU fails only if page has been isolated from
3542 * the LRU since we looked at it and that usually means either global
3543 * reclaim or migration going on. The page will either get back to the
3545 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3546 * (!PageCgroupUsed) or moved to a different group. The page will
3547 * disappear in the next attempt.
3549 static int mem_cgroup_move_parent(struct page *page,
3550 struct page_cgroup *pc,
3551 struct mem_cgroup *child)
3553 struct mem_cgroup *parent;
3554 unsigned int nr_pages;
3555 unsigned long uninitialized_var(flags);
3558 VM_BUG_ON(mem_cgroup_is_root(child));
3561 if (!get_page_unless_zero(page))
3563 if (isolate_lru_page(page))
3566 nr_pages = hpage_nr_pages(page);
3568 parent = parent_mem_cgroup(child);
3570 * If no parent, move charges to root cgroup.
3573 parent = root_mem_cgroup;
3576 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3577 flags = compound_lock_irqsave(page);
3580 ret = mem_cgroup_move_account(page, nr_pages,
3583 __mem_cgroup_cancel_local_charge(child, nr_pages);
3586 compound_unlock_irqrestore(page, flags);
3587 putback_lru_page(page);
3594 #ifdef CONFIG_MEMCG_SWAP
3595 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
3598 int val = (charge) ? 1 : -1;
3599 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
3603 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3604 * @entry: swap entry to be moved
3605 * @from: mem_cgroup which the entry is moved from
3606 * @to: mem_cgroup which the entry is moved to
3608 * It succeeds only when the swap_cgroup's record for this entry is the same
3609 * as the mem_cgroup's id of @from.
3611 * Returns 0 on success, -EINVAL on failure.
3613 * The caller must have charged to @to, IOW, called res_counter_charge() about
3614 * both res and memsw, and called css_get().
3616 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3617 struct mem_cgroup *from, struct mem_cgroup *to)
3619 unsigned short old_id, new_id;
3621 old_id = mem_cgroup_id(from);
3622 new_id = mem_cgroup_id(to);
3624 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3625 mem_cgroup_swap_statistics(from, false);
3626 mem_cgroup_swap_statistics(to, true);
3628 * This function is only called from task migration context now.
3629 * It postpones res_counter and refcount handling till the end
3630 * of task migration(mem_cgroup_clear_mc()) for performance
3631 * improvement. But we cannot postpone css_get(to) because if
3632 * the process that has been moved to @to does swap-in, the
3633 * refcount of @to might be decreased to 0.
3635 * We are in attach() phase, so the cgroup is guaranteed to be
3636 * alive, so we can just call css_get().
3644 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3645 struct mem_cgroup *from, struct mem_cgroup *to)
3651 #ifdef CONFIG_DEBUG_VM
3652 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3654 struct page_cgroup *pc;
3656 pc = lookup_page_cgroup(page);
3658 * Can be NULL while feeding pages into the page allocator for
3659 * the first time, i.e. during boot or memory hotplug;
3660 * or when mem_cgroup_disabled().
3662 if (likely(pc) && PageCgroupUsed(pc))
3667 bool mem_cgroup_bad_page_check(struct page *page)
3669 if (mem_cgroup_disabled())
3672 return lookup_page_cgroup_used(page) != NULL;
3675 void mem_cgroup_print_bad_page(struct page *page)
3677 struct page_cgroup *pc;
3679 pc = lookup_page_cgroup_used(page);
3681 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
3682 pc, pc->flags, pc->mem_cgroup);
3687 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3688 unsigned long long val)
3691 u64 memswlimit, memlimit;
3693 int children = mem_cgroup_count_children(memcg);
3694 u64 curusage, oldusage;
3698 * For keeping hierarchical_reclaim simple, how long we should retry
3699 * is depends on callers. We set our retry-count to be function
3700 * of # of children which we should visit in this loop.
3702 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3704 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3707 while (retry_count) {
3708 if (signal_pending(current)) {
3713 * Rather than hide all in some function, I do this in
3714 * open coded manner. You see what this really does.
3715 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3717 mutex_lock(&set_limit_mutex);
3718 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3719 if (memswlimit < val) {
3721 mutex_unlock(&set_limit_mutex);
3725 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3729 ret = res_counter_set_limit(&memcg->res, val);
3731 if (memswlimit == val)
3732 memcg->memsw_is_minimum = true;
3734 memcg->memsw_is_minimum = false;
3736 mutex_unlock(&set_limit_mutex);
3741 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3742 MEM_CGROUP_RECLAIM_SHRINK);
3743 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3744 /* Usage is reduced ? */
3745 if (curusage >= oldusage)
3748 oldusage = curusage;
3750 if (!ret && enlarge)
3751 memcg_oom_recover(memcg);
3756 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3757 unsigned long long val)
3760 u64 memlimit, memswlimit, oldusage, curusage;
3761 int children = mem_cgroup_count_children(memcg);
3765 /* see mem_cgroup_resize_res_limit */
3766 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3767 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3768 while (retry_count) {
3769 if (signal_pending(current)) {
3774 * Rather than hide all in some function, I do this in
3775 * open coded manner. You see what this really does.
3776 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3778 mutex_lock(&set_limit_mutex);
3779 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3780 if (memlimit > val) {
3782 mutex_unlock(&set_limit_mutex);
3785 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3786 if (memswlimit < val)
3788 ret = res_counter_set_limit(&memcg->memsw, val);
3790 if (memlimit == val)
3791 memcg->memsw_is_minimum = true;
3793 memcg->memsw_is_minimum = false;
3795 mutex_unlock(&set_limit_mutex);
3800 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3801 MEM_CGROUP_RECLAIM_NOSWAP |
3802 MEM_CGROUP_RECLAIM_SHRINK);
3803 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3804 /* Usage is reduced ? */
3805 if (curusage >= oldusage)
3808 oldusage = curusage;
3810 if (!ret && enlarge)
3811 memcg_oom_recover(memcg);
3815 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3817 unsigned long *total_scanned)
3819 unsigned long nr_reclaimed = 0;
3820 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3821 unsigned long reclaimed;
3823 struct mem_cgroup_tree_per_zone *mctz;
3824 unsigned long long excess;
3825 unsigned long nr_scanned;
3830 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3832 * This loop can run a while, specially if mem_cgroup's continuously
3833 * keep exceeding their soft limit and putting the system under
3840 mz = mem_cgroup_largest_soft_limit_node(mctz);
3845 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
3846 gfp_mask, &nr_scanned);
3847 nr_reclaimed += reclaimed;
3848 *total_scanned += nr_scanned;
3849 spin_lock_irq(&mctz->lock);
3852 * If we failed to reclaim anything from this memory cgroup
3853 * it is time to move on to the next cgroup
3859 * Loop until we find yet another one.
3861 * By the time we get the soft_limit lock
3862 * again, someone might have aded the
3863 * group back on the RB tree. Iterate to
3864 * make sure we get a different mem.
3865 * mem_cgroup_largest_soft_limit_node returns
3866 * NULL if no other cgroup is present on
3870 __mem_cgroup_largest_soft_limit_node(mctz);
3872 css_put(&next_mz->memcg->css);
3873 else /* next_mz == NULL or other memcg */
3877 __mem_cgroup_remove_exceeded(mz, mctz);
3878 excess = res_counter_soft_limit_excess(&mz->memcg->res);
3880 * One school of thought says that we should not add
3881 * back the node to the tree if reclaim returns 0.
3882 * But our reclaim could return 0, simply because due
3883 * to priority we are exposing a smaller subset of
3884 * memory to reclaim from. Consider this as a longer
3887 /* If excess == 0, no tree ops */
3888 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3889 spin_unlock_irq(&mctz->lock);
3890 css_put(&mz->memcg->css);
3893 * Could not reclaim anything and there are no more
3894 * mem cgroups to try or we seem to be looping without
3895 * reclaiming anything.
3897 if (!nr_reclaimed &&
3899 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3901 } while (!nr_reclaimed);
3903 css_put(&next_mz->memcg->css);
3904 return nr_reclaimed;
3908 * mem_cgroup_force_empty_list - clears LRU of a group
3909 * @memcg: group to clear
3912 * @lru: lru to to clear
3914 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
3915 * reclaim the pages page themselves - pages are moved to the parent (or root)
3918 static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
3919 int node, int zid, enum lru_list lru)
3921 struct lruvec *lruvec;
3922 unsigned long flags;
3923 struct list_head *list;
3927 zone = &NODE_DATA(node)->node_zones[zid];
3928 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
3929 list = &lruvec->lists[lru];
3933 struct page_cgroup *pc;
3936 spin_lock_irqsave(&zone->lru_lock, flags);
3937 if (list_empty(list)) {
3938 spin_unlock_irqrestore(&zone->lru_lock, flags);
3941 page = list_entry(list->prev, struct page, lru);
3943 list_move(&page->lru, list);
3945 spin_unlock_irqrestore(&zone->lru_lock, flags);
3948 spin_unlock_irqrestore(&zone->lru_lock, flags);
3950 pc = lookup_page_cgroup(page);
3952 if (mem_cgroup_move_parent(page, pc, memcg)) {
3953 /* found lock contention or "pc" is obsolete. */
3958 } while (!list_empty(list));
3962 * make mem_cgroup's charge to be 0 if there is no task by moving
3963 * all the charges and pages to the parent.
3964 * This enables deleting this mem_cgroup.
3966 * Caller is responsible for holding css reference on the memcg.
3968 static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
3974 /* This is for making all *used* pages to be on LRU. */
3975 lru_add_drain_all();
3976 drain_all_stock_sync(memcg);
3977 mem_cgroup_start_move(memcg);
3978 for_each_node_state(node, N_MEMORY) {
3979 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
3982 mem_cgroup_force_empty_list(memcg,
3987 mem_cgroup_end_move(memcg);
3988 memcg_oom_recover(memcg);
3992 * Kernel memory may not necessarily be trackable to a specific
3993 * process. So they are not migrated, and therefore we can't
3994 * expect their value to drop to 0 here.
3995 * Having res filled up with kmem only is enough.
3997 * This is a safety check because mem_cgroup_force_empty_list
3998 * could have raced with mem_cgroup_replace_page_cache callers
3999 * so the lru seemed empty but the page could have been added
4000 * right after the check. RES_USAGE should be safe as we always
4001 * charge before adding to the LRU.
4003 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4004 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4005 } while (usage > 0);
4009 * Test whether @memcg has children, dead or alive. Note that this
4010 * function doesn't care whether @memcg has use_hierarchy enabled and
4011 * returns %true if there are child csses according to the cgroup
4012 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
4014 static inline bool memcg_has_children(struct mem_cgroup *memcg)
4019 * The lock does not prevent addition or deletion of children, but
4020 * it prevents a new child from being initialized based on this
4021 * parent in css_online(), so it's enough to decide whether
4022 * hierarchically inherited attributes can still be changed or not.
4024 lockdep_assert_held(&memcg_create_mutex);
4027 ret = css_next_child(NULL, &memcg->css);
4033 * Reclaims as many pages from the given memcg as possible and moves
4034 * the rest to the parent.
4036 * Caller is responsible for holding css reference for memcg.
4038 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4040 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4042 /* we call try-to-free pages for make this cgroup empty */
4043 lru_add_drain_all();
4044 /* try to free all pages in this cgroup */
4045 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4048 if (signal_pending(current))
4051 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4055 /* maybe some writeback is necessary */
4056 congestion_wait(BLK_RW_ASYNC, HZ/10);
4064 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
4065 char *buf, size_t nbytes,
4068 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4070 if (mem_cgroup_is_root(memcg))
4072 return mem_cgroup_force_empty(memcg) ?: nbytes;
4075 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4078 return mem_cgroup_from_css(css)->use_hierarchy;
4081 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4082 struct cftype *cft, u64 val)
4085 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4086 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
4088 mutex_lock(&memcg_create_mutex);
4090 if (memcg->use_hierarchy == val)
4094 * If parent's use_hierarchy is set, we can't make any modifications
4095 * in the child subtrees. If it is unset, then the change can
4096 * occur, provided the current cgroup has no children.
4098 * For the root cgroup, parent_mem is NULL, we allow value to be
4099 * set if there are no children.
4101 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4102 (val == 1 || val == 0)) {
4103 if (!memcg_has_children(memcg))
4104 memcg->use_hierarchy = val;
4111 mutex_unlock(&memcg_create_mutex);
4116 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
4117 enum mem_cgroup_stat_index idx)
4119 struct mem_cgroup *iter;
4122 /* Per-cpu values can be negative, use a signed accumulator */
4123 for_each_mem_cgroup_tree(iter, memcg)
4124 val += mem_cgroup_read_stat(iter, idx);
4126 if (val < 0) /* race ? */
4131 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
4135 if (!mem_cgroup_is_root(memcg)) {
4137 return res_counter_read_u64(&memcg->res, RES_USAGE);
4139 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
4143 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4144 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4146 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4147 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
4150 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
4152 return val << PAGE_SHIFT;
4156 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
4159 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4160 enum res_type type = MEMFILE_TYPE(cft->private);
4161 int name = MEMFILE_ATTR(cft->private);
4165 if (name == RES_USAGE)
4166 return mem_cgroup_usage(memcg, false);
4167 return res_counter_read_u64(&memcg->res, name);
4169 if (name == RES_USAGE)
4170 return mem_cgroup_usage(memcg, true);
4171 return res_counter_read_u64(&memcg->memsw, name);
4173 return res_counter_read_u64(&memcg->kmem, name);
4180 #ifdef CONFIG_MEMCG_KMEM
4181 /* should be called with activate_kmem_mutex held */
4182 static int __memcg_activate_kmem(struct mem_cgroup *memcg,
4183 unsigned long long limit)
4188 if (memcg_kmem_is_active(memcg))
4192 * We are going to allocate memory for data shared by all memory
4193 * cgroups so let's stop accounting here.
4195 memcg_stop_kmem_account();
4198 * For simplicity, we won't allow this to be disabled. It also can't
4199 * be changed if the cgroup has children already, or if tasks had
4202 * If tasks join before we set the limit, a person looking at
4203 * kmem.usage_in_bytes will have no way to determine when it took
4204 * place, which makes the value quite meaningless.
4206 * After it first became limited, changes in the value of the limit are
4207 * of course permitted.
4209 mutex_lock(&memcg_create_mutex);
4210 if (cgroup_has_tasks(memcg->css.cgroup) ||
4211 (memcg->use_hierarchy && memcg_has_children(memcg)))
4213 mutex_unlock(&memcg_create_mutex);
4217 memcg_id = ida_simple_get(&kmem_limited_groups,
4218 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
4225 * Make sure we have enough space for this cgroup in each root cache's
4228 mutex_lock(&memcg_slab_mutex);
4229 err = memcg_update_all_caches(memcg_id + 1);
4230 mutex_unlock(&memcg_slab_mutex);
4234 memcg->kmemcg_id = memcg_id;
4235 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
4238 * We couldn't have accounted to this cgroup, because it hasn't got the
4239 * active bit set yet, so this should succeed.
4241 err = res_counter_set_limit(&memcg->kmem, limit);
4244 static_key_slow_inc(&memcg_kmem_enabled_key);
4246 * Setting the active bit after enabling static branching will
4247 * guarantee no one starts accounting before all call sites are
4250 memcg_kmem_set_active(memcg);
4252 memcg_resume_kmem_account();
4256 ida_simple_remove(&kmem_limited_groups, memcg_id);
4260 static int memcg_activate_kmem(struct mem_cgroup *memcg,
4261 unsigned long long limit)
4265 mutex_lock(&activate_kmem_mutex);
4266 ret = __memcg_activate_kmem(memcg, limit);
4267 mutex_unlock(&activate_kmem_mutex);
4271 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
4272 unsigned long long val)
4276 if (!memcg_kmem_is_active(memcg))
4277 ret = memcg_activate_kmem(memcg, val);
4279 ret = res_counter_set_limit(&memcg->kmem, val);
4283 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
4286 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4291 mutex_lock(&activate_kmem_mutex);
4293 * If the parent cgroup is not kmem-active now, it cannot be activated
4294 * after this point, because it has at least one child already.
4296 if (memcg_kmem_is_active(parent))
4297 ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX);
4298 mutex_unlock(&activate_kmem_mutex);
4302 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
4303 unsigned long long val)
4307 #endif /* CONFIG_MEMCG_KMEM */
4310 * The user of this function is...
4313 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
4314 char *buf, size_t nbytes, loff_t off)
4316 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4319 unsigned long long val;
4322 buf = strstrip(buf);
4323 type = MEMFILE_TYPE(of_cft(of)->private);
4324 name = MEMFILE_ATTR(of_cft(of)->private);
4328 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
4332 /* This function does all necessary parse...reuse it */
4333 ret = res_counter_memparse_write_strategy(buf, &val);
4337 ret = mem_cgroup_resize_limit(memcg, val);
4338 else if (type == _MEMSWAP)
4339 ret = mem_cgroup_resize_memsw_limit(memcg, val);
4340 else if (type == _KMEM)
4341 ret = memcg_update_kmem_limit(memcg, val);
4345 case RES_SOFT_LIMIT:
4346 ret = res_counter_memparse_write_strategy(buf, &val);
4350 * For memsw, soft limits are hard to implement in terms
4351 * of semantics, for now, we support soft limits for
4352 * control without swap
4355 ret = res_counter_set_soft_limit(&memcg->res, val);
4360 ret = -EINVAL; /* should be BUG() ? */
4363 return ret ?: nbytes;
4366 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
4367 unsigned long long *mem_limit, unsigned long long *memsw_limit)
4369 unsigned long long min_limit, min_memsw_limit, tmp;
4371 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4372 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4373 if (!memcg->use_hierarchy)
4376 while (memcg->css.parent) {
4377 memcg = mem_cgroup_from_css(memcg->css.parent);
4378 if (!memcg->use_hierarchy)
4380 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
4381 min_limit = min(min_limit, tmp);
4382 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4383 min_memsw_limit = min(min_memsw_limit, tmp);
4386 *mem_limit = min_limit;
4387 *memsw_limit = min_memsw_limit;
4390 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
4391 size_t nbytes, loff_t off)
4393 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4397 type = MEMFILE_TYPE(of_cft(of)->private);
4398 name = MEMFILE_ATTR(of_cft(of)->private);
4403 res_counter_reset_max(&memcg->res);
4404 else if (type == _MEMSWAP)
4405 res_counter_reset_max(&memcg->memsw);
4406 else if (type == _KMEM)
4407 res_counter_reset_max(&memcg->kmem);
4413 res_counter_reset_failcnt(&memcg->res);
4414 else if (type == _MEMSWAP)
4415 res_counter_reset_failcnt(&memcg->memsw);
4416 else if (type == _KMEM)
4417 res_counter_reset_failcnt(&memcg->kmem);
4426 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
4429 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
4433 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4434 struct cftype *cft, u64 val)
4436 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4438 if (val >= (1 << NR_MOVE_TYPE))
4442 * No kind of locking is needed in here, because ->can_attach() will
4443 * check this value once in the beginning of the process, and then carry
4444 * on with stale data. This means that changes to this value will only
4445 * affect task migrations starting after the change.
4447 memcg->move_charge_at_immigrate = val;
4451 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
4452 struct cftype *cft, u64 val)
4459 static int memcg_numa_stat_show(struct seq_file *m, void *v)
4463 unsigned int lru_mask;
4466 static const struct numa_stat stats[] = {
4467 { "total", LRU_ALL },
4468 { "file", LRU_ALL_FILE },
4469 { "anon", LRU_ALL_ANON },
4470 { "unevictable", BIT(LRU_UNEVICTABLE) },
4472 const struct numa_stat *stat;
4475 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
4477 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
4478 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
4479 seq_printf(m, "%s=%lu", stat->name, nr);
4480 for_each_node_state(nid, N_MEMORY) {
4481 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4483 seq_printf(m, " N%d=%lu", nid, nr);
4488 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
4489 struct mem_cgroup *iter;
4492 for_each_mem_cgroup_tree(iter, memcg)
4493 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
4494 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
4495 for_each_node_state(nid, N_MEMORY) {
4497 for_each_mem_cgroup_tree(iter, memcg)
4498 nr += mem_cgroup_node_nr_lru_pages(
4499 iter, nid, stat->lru_mask);
4500 seq_printf(m, " N%d=%lu", nid, nr);
4507 #endif /* CONFIG_NUMA */
4509 static inline void mem_cgroup_lru_names_not_uptodate(void)
4511 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
4514 static int memcg_stat_show(struct seq_file *m, void *v)
4516 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
4517 struct mem_cgroup *mi;
4520 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4521 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
4523 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
4524 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
4527 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
4528 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
4529 mem_cgroup_read_events(memcg, i));
4531 for (i = 0; i < NR_LRU_LISTS; i++)
4532 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
4533 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
4535 /* Hierarchical information */
4537 unsigned long long limit, memsw_limit;
4538 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
4539 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
4540 if (do_swap_account)
4541 seq_printf(m, "hierarchical_memsw_limit %llu\n",
4545 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4548 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
4550 for_each_mem_cgroup_tree(mi, memcg)
4551 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
4552 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
4555 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
4556 unsigned long long val = 0;
4558 for_each_mem_cgroup_tree(mi, memcg)
4559 val += mem_cgroup_read_events(mi, i);
4560 seq_printf(m, "total_%s %llu\n",
4561 mem_cgroup_events_names[i], val);
4564 for (i = 0; i < NR_LRU_LISTS; i++) {
4565 unsigned long long val = 0;
4567 for_each_mem_cgroup_tree(mi, memcg)
4568 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
4569 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
4572 #ifdef CONFIG_DEBUG_VM
4575 struct mem_cgroup_per_zone *mz;
4576 struct zone_reclaim_stat *rstat;
4577 unsigned long recent_rotated[2] = {0, 0};
4578 unsigned long recent_scanned[2] = {0, 0};
4580 for_each_online_node(nid)
4581 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4582 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
4583 rstat = &mz->lruvec.reclaim_stat;
4585 recent_rotated[0] += rstat->recent_rotated[0];
4586 recent_rotated[1] += rstat->recent_rotated[1];
4587 recent_scanned[0] += rstat->recent_scanned[0];
4588 recent_scanned[1] += rstat->recent_scanned[1];
4590 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
4591 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
4592 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
4593 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
4600 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
4603 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4605 return mem_cgroup_swappiness(memcg);
4608 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
4609 struct cftype *cft, u64 val)
4611 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4617 memcg->swappiness = val;
4619 vm_swappiness = val;
4624 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4626 struct mem_cgroup_threshold_ary *t;
4632 t = rcu_dereference(memcg->thresholds.primary);
4634 t = rcu_dereference(memcg->memsw_thresholds.primary);
4639 usage = mem_cgroup_usage(memcg, swap);
4642 * current_threshold points to threshold just below or equal to usage.
4643 * If it's not true, a threshold was crossed after last
4644 * call of __mem_cgroup_threshold().
4646 i = t->current_threshold;
4649 * Iterate backward over array of thresholds starting from
4650 * current_threshold and check if a threshold is crossed.
4651 * If none of thresholds below usage is crossed, we read
4652 * only one element of the array here.
4654 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4655 eventfd_signal(t->entries[i].eventfd, 1);
4657 /* i = current_threshold + 1 */
4661 * Iterate forward over array of thresholds starting from
4662 * current_threshold+1 and check if a threshold is crossed.
4663 * If none of thresholds above usage is crossed, we read
4664 * only one element of the array here.
4666 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4667 eventfd_signal(t->entries[i].eventfd, 1);
4669 /* Update current_threshold */
4670 t->current_threshold = i - 1;
4675 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4678 __mem_cgroup_threshold(memcg, false);
4679 if (do_swap_account)
4680 __mem_cgroup_threshold(memcg, true);
4682 memcg = parent_mem_cgroup(memcg);
4686 static int compare_thresholds(const void *a, const void *b)
4688 const struct mem_cgroup_threshold *_a = a;
4689 const struct mem_cgroup_threshold *_b = b;
4691 if (_a->threshold > _b->threshold)
4694 if (_a->threshold < _b->threshold)
4700 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4702 struct mem_cgroup_eventfd_list *ev;
4704 spin_lock(&memcg_oom_lock);
4706 list_for_each_entry(ev, &memcg->oom_notify, list)
4707 eventfd_signal(ev->eventfd, 1);
4709 spin_unlock(&memcg_oom_lock);
4713 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4715 struct mem_cgroup *iter;
4717 for_each_mem_cgroup_tree(iter, memcg)
4718 mem_cgroup_oom_notify_cb(iter);
4721 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4722 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
4724 struct mem_cgroup_thresholds *thresholds;
4725 struct mem_cgroup_threshold_ary *new;
4726 u64 threshold, usage;
4729 ret = res_counter_memparse_write_strategy(args, &threshold);
4733 mutex_lock(&memcg->thresholds_lock);
4736 thresholds = &memcg->thresholds;
4737 usage = mem_cgroup_usage(memcg, false);
4738 } else if (type == _MEMSWAP) {
4739 thresholds = &memcg->memsw_thresholds;
4740 usage = mem_cgroup_usage(memcg, true);
4744 /* Check if a threshold crossed before adding a new one */
4745 if (thresholds->primary)
4746 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4748 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4750 /* Allocate memory for new array of thresholds */
4751 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4759 /* Copy thresholds (if any) to new array */
4760 if (thresholds->primary) {
4761 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4762 sizeof(struct mem_cgroup_threshold));
4765 /* Add new threshold */
4766 new->entries[size - 1].eventfd = eventfd;
4767 new->entries[size - 1].threshold = threshold;
4769 /* Sort thresholds. Registering of new threshold isn't time-critical */
4770 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4771 compare_thresholds, NULL);
4773 /* Find current threshold */
4774 new->current_threshold = -1;
4775 for (i = 0; i < size; i++) {
4776 if (new->entries[i].threshold <= usage) {
4778 * new->current_threshold will not be used until
4779 * rcu_assign_pointer(), so it's safe to increment
4782 ++new->current_threshold;
4787 /* Free old spare buffer and save old primary buffer as spare */
4788 kfree(thresholds->spare);
4789 thresholds->spare = thresholds->primary;
4791 rcu_assign_pointer(thresholds->primary, new);
4793 /* To be sure that nobody uses thresholds */
4797 mutex_unlock(&memcg->thresholds_lock);
4802 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4803 struct eventfd_ctx *eventfd, const char *args)
4805 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4808 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4809 struct eventfd_ctx *eventfd, const char *args)
4811 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4814 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4815 struct eventfd_ctx *eventfd, enum res_type type)
4817 struct mem_cgroup_thresholds *thresholds;
4818 struct mem_cgroup_threshold_ary *new;
4822 mutex_lock(&memcg->thresholds_lock);
4825 thresholds = &memcg->thresholds;
4826 usage = mem_cgroup_usage(memcg, false);
4827 } else if (type == _MEMSWAP) {
4828 thresholds = &memcg->memsw_thresholds;
4829 usage = mem_cgroup_usage(memcg, true);
4833 if (!thresholds->primary)
4836 /* Check if a threshold crossed before removing */
4837 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4839 /* Calculate new number of threshold */
4841 for (i = 0; i < thresholds->primary->size; i++) {
4842 if (thresholds->primary->entries[i].eventfd != eventfd)
4846 new = thresholds->spare;
4848 /* Set thresholds array to NULL if we don't have thresholds */
4857 /* Copy thresholds and find current threshold */
4858 new->current_threshold = -1;
4859 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4860 if (thresholds->primary->entries[i].eventfd == eventfd)
4863 new->entries[j] = thresholds->primary->entries[i];
4864 if (new->entries[j].threshold <= usage) {
4866 * new->current_threshold will not be used
4867 * until rcu_assign_pointer(), so it's safe to increment
4870 ++new->current_threshold;
4876 /* Swap primary and spare array */
4877 thresholds->spare = thresholds->primary;
4878 /* If all events are unregistered, free the spare array */
4880 kfree(thresholds->spare);
4881 thresholds->spare = NULL;
4884 rcu_assign_pointer(thresholds->primary, new);
4886 /* To be sure that nobody uses thresholds */
4889 mutex_unlock(&memcg->thresholds_lock);
4892 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4893 struct eventfd_ctx *eventfd)
4895 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4898 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4899 struct eventfd_ctx *eventfd)
4901 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4904 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4905 struct eventfd_ctx *eventfd, const char *args)
4907 struct mem_cgroup_eventfd_list *event;
4909 event = kmalloc(sizeof(*event), GFP_KERNEL);
4913 spin_lock(&memcg_oom_lock);
4915 event->eventfd = eventfd;
4916 list_add(&event->list, &memcg->oom_notify);
4918 /* already in OOM ? */
4919 if (atomic_read(&memcg->under_oom))
4920 eventfd_signal(eventfd, 1);
4921 spin_unlock(&memcg_oom_lock);
4926 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4927 struct eventfd_ctx *eventfd)
4929 struct mem_cgroup_eventfd_list *ev, *tmp;
4931 spin_lock(&memcg_oom_lock);
4933 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4934 if (ev->eventfd == eventfd) {
4935 list_del(&ev->list);
4940 spin_unlock(&memcg_oom_lock);
4943 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4945 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
4947 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4948 seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
4952 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4953 struct cftype *cft, u64 val)
4955 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4957 /* cannot set to root cgroup and only 0 and 1 are allowed */
4958 if (!css->parent || !((val == 0) || (val == 1)))
4961 memcg->oom_kill_disable = val;
4963 memcg_oom_recover(memcg);
4968 #ifdef CONFIG_MEMCG_KMEM
4969 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4973 memcg->kmemcg_id = -1;
4974 ret = memcg_propagate_kmem(memcg);
4978 return mem_cgroup_sockets_init(memcg, ss);
4981 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
4983 mem_cgroup_sockets_destroy(memcg);
4986 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
4988 if (!memcg_kmem_is_active(memcg))
4992 * kmem charges can outlive the cgroup. In the case of slab
4993 * pages, for instance, a page contain objects from various
4994 * processes. As we prevent from taking a reference for every
4995 * such allocation we have to be careful when doing uncharge
4996 * (see memcg_uncharge_kmem) and here during offlining.
4998 * The idea is that that only the _last_ uncharge which sees
4999 * the dead memcg will drop the last reference. An additional
5000 * reference is taken here before the group is marked dead
5001 * which is then paired with css_put during uncharge resp. here.
5003 * Although this might sound strange as this path is called from
5004 * css_offline() when the referencemight have dropped down to 0 and
5005 * shouldn't be incremented anymore (css_tryget_online() would
5006 * fail) we do not have other options because of the kmem
5007 * allocations lifetime.
5009 css_get(&memcg->css);
5011 memcg_kmem_mark_dead(memcg);
5013 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5016 if (memcg_kmem_test_and_clear_dead(memcg))
5017 css_put(&memcg->css);
5020 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5025 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5029 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5035 * DO NOT USE IN NEW FILES.
5037 * "cgroup.event_control" implementation.
5039 * This is way over-engineered. It tries to support fully configurable
5040 * events for each user. Such level of flexibility is completely
5041 * unnecessary especially in the light of the planned unified hierarchy.
5043 * Please deprecate this and replace with something simpler if at all
5048 * Unregister event and free resources.
5050 * Gets called from workqueue.
5052 static void memcg_event_remove(struct work_struct *work)
5054 struct mem_cgroup_event *event =
5055 container_of(work, struct mem_cgroup_event, remove);
5056 struct mem_cgroup *memcg = event->memcg;
5058 remove_wait_queue(event->wqh, &event->wait);
5060 event->unregister_event(memcg, event->eventfd);
5062 /* Notify userspace the event is going away. */
5063 eventfd_signal(event->eventfd, 1);
5065 eventfd_ctx_put(event->eventfd);
5067 css_put(&memcg->css);
5071 * Gets called on POLLHUP on eventfd when user closes it.
5073 * Called with wqh->lock held and interrupts disabled.
5075 static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
5076 int sync, void *key)
5078 struct mem_cgroup_event *event =
5079 container_of(wait, struct mem_cgroup_event, wait);
5080 struct mem_cgroup *memcg = event->memcg;
5081 unsigned long flags = (unsigned long)key;
5083 if (flags & POLLHUP) {
5085 * If the event has been detached at cgroup removal, we
5086 * can simply return knowing the other side will cleanup
5089 * We can't race against event freeing since the other
5090 * side will require wqh->lock via remove_wait_queue(),
5093 spin_lock(&memcg->event_list_lock);
5094 if (!list_empty(&event->list)) {
5095 list_del_init(&event->list);
5097 * We are in atomic context, but cgroup_event_remove()
5098 * may sleep, so we have to call it in workqueue.
5100 schedule_work(&event->remove);
5102 spin_unlock(&memcg->event_list_lock);
5108 static void memcg_event_ptable_queue_proc(struct file *file,
5109 wait_queue_head_t *wqh, poll_table *pt)
5111 struct mem_cgroup_event *event =
5112 container_of(pt, struct mem_cgroup_event, pt);
5115 add_wait_queue(wqh, &event->wait);
5119 * DO NOT USE IN NEW FILES.
5121 * Parse input and register new cgroup event handler.
5123 * Input must be in format '<event_fd> <control_fd> <args>'.
5124 * Interpretation of args is defined by control file implementation.
5126 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
5127 char *buf, size_t nbytes, loff_t off)
5129 struct cgroup_subsys_state *css = of_css(of);
5130 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5131 struct mem_cgroup_event *event;
5132 struct cgroup_subsys_state *cfile_css;
5133 unsigned int efd, cfd;
5140 buf = strstrip(buf);
5142 efd = simple_strtoul(buf, &endp, 10);
5147 cfd = simple_strtoul(buf, &endp, 10);
5148 if ((*endp != ' ') && (*endp != '\0'))
5152 event = kzalloc(sizeof(*event), GFP_KERNEL);
5156 event->memcg = memcg;
5157 INIT_LIST_HEAD(&event->list);
5158 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
5159 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
5160 INIT_WORK(&event->remove, memcg_event_remove);
5168 event->eventfd = eventfd_ctx_fileget(efile.file);
5169 if (IS_ERR(event->eventfd)) {
5170 ret = PTR_ERR(event->eventfd);
5177 goto out_put_eventfd;
5180 /* the process need read permission on control file */
5181 /* AV: shouldn't we check that it's been opened for read instead? */
5182 ret = inode_permission(file_inode(cfile.file), MAY_READ);
5187 * Determine the event callbacks and set them in @event. This used
5188 * to be done via struct cftype but cgroup core no longer knows
5189 * about these events. The following is crude but the whole thing
5190 * is for compatibility anyway.
5192 * DO NOT ADD NEW FILES.
5194 name = cfile.file->f_dentry->d_name.name;
5196 if (!strcmp(name, "memory.usage_in_bytes")) {
5197 event->register_event = mem_cgroup_usage_register_event;
5198 event->unregister_event = mem_cgroup_usage_unregister_event;
5199 } else if (!strcmp(name, "memory.oom_control")) {
5200 event->register_event = mem_cgroup_oom_register_event;
5201 event->unregister_event = mem_cgroup_oom_unregister_event;
5202 } else if (!strcmp(name, "memory.pressure_level")) {
5203 event->register_event = vmpressure_register_event;
5204 event->unregister_event = vmpressure_unregister_event;
5205 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
5206 event->register_event = memsw_cgroup_usage_register_event;
5207 event->unregister_event = memsw_cgroup_usage_unregister_event;
5214 * Verify @cfile should belong to @css. Also, remaining events are
5215 * automatically removed on cgroup destruction but the removal is
5216 * asynchronous, so take an extra ref on @css.
5218 cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
5219 &memory_cgrp_subsys);
5221 if (IS_ERR(cfile_css))
5223 if (cfile_css != css) {
5228 ret = event->register_event(memcg, event->eventfd, buf);
5232 efile.file->f_op->poll(efile.file, &event->pt);
5234 spin_lock(&memcg->event_list_lock);
5235 list_add(&event->list, &memcg->event_list);
5236 spin_unlock(&memcg->event_list_lock);
5248 eventfd_ctx_put(event->eventfd);
5257 static struct cftype mem_cgroup_files[] = {
5259 .name = "usage_in_bytes",
5260 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5261 .read_u64 = mem_cgroup_read_u64,
5264 .name = "max_usage_in_bytes",
5265 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5266 .write = mem_cgroup_reset,
5267 .read_u64 = mem_cgroup_read_u64,
5270 .name = "limit_in_bytes",
5271 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5272 .write = mem_cgroup_write,
5273 .read_u64 = mem_cgroup_read_u64,
5276 .name = "soft_limit_in_bytes",
5277 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5278 .write = mem_cgroup_write,
5279 .read_u64 = mem_cgroup_read_u64,
5283 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5284 .write = mem_cgroup_reset,
5285 .read_u64 = mem_cgroup_read_u64,
5289 .seq_show = memcg_stat_show,
5292 .name = "force_empty",
5293 .write = mem_cgroup_force_empty_write,
5296 .name = "use_hierarchy",
5297 .write_u64 = mem_cgroup_hierarchy_write,
5298 .read_u64 = mem_cgroup_hierarchy_read,
5301 .name = "cgroup.event_control", /* XXX: for compat */
5302 .write = memcg_write_event_control,
5303 .flags = CFTYPE_NO_PREFIX,
5307 .name = "swappiness",
5308 .read_u64 = mem_cgroup_swappiness_read,
5309 .write_u64 = mem_cgroup_swappiness_write,
5312 .name = "move_charge_at_immigrate",
5313 .read_u64 = mem_cgroup_move_charge_read,
5314 .write_u64 = mem_cgroup_move_charge_write,
5317 .name = "oom_control",
5318 .seq_show = mem_cgroup_oom_control_read,
5319 .write_u64 = mem_cgroup_oom_control_write,
5320 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
5323 .name = "pressure_level",
5327 .name = "numa_stat",
5328 .seq_show = memcg_numa_stat_show,
5331 #ifdef CONFIG_MEMCG_KMEM
5333 .name = "kmem.limit_in_bytes",
5334 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5335 .write = mem_cgroup_write,
5336 .read_u64 = mem_cgroup_read_u64,
5339 .name = "kmem.usage_in_bytes",
5340 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5341 .read_u64 = mem_cgroup_read_u64,
5344 .name = "kmem.failcnt",
5345 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5346 .write = mem_cgroup_reset,
5347 .read_u64 = mem_cgroup_read_u64,
5350 .name = "kmem.max_usage_in_bytes",
5351 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5352 .write = mem_cgroup_reset,
5353 .read_u64 = mem_cgroup_read_u64,
5355 #ifdef CONFIG_SLABINFO
5357 .name = "kmem.slabinfo",
5358 .seq_show = mem_cgroup_slabinfo_read,
5362 { }, /* terminate */
5365 #ifdef CONFIG_MEMCG_SWAP
5366 static struct cftype memsw_cgroup_files[] = {
5368 .name = "memsw.usage_in_bytes",
5369 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
5370 .read_u64 = mem_cgroup_read_u64,
5373 .name = "memsw.max_usage_in_bytes",
5374 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
5375 .write = mem_cgroup_reset,
5376 .read_u64 = mem_cgroup_read_u64,
5379 .name = "memsw.limit_in_bytes",
5380 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
5381 .write = mem_cgroup_write,
5382 .read_u64 = mem_cgroup_read_u64,
5385 .name = "memsw.failcnt",
5386 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
5387 .write = mem_cgroup_reset,
5388 .read_u64 = mem_cgroup_read_u64,
5390 { }, /* terminate */
5393 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5395 struct mem_cgroup_per_node *pn;
5396 struct mem_cgroup_per_zone *mz;
5397 int zone, tmp = node;
5399 * This routine is called against possible nodes.
5400 * But it's BUG to call kmalloc() against offline node.
5402 * TODO: this routine can waste much memory for nodes which will
5403 * never be onlined. It's better to use memory hotplug callback
5406 if (!node_state(node, N_NORMAL_MEMORY))
5408 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5412 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
5413 mz = &pn->zoneinfo[zone];
5414 lruvec_init(&mz->lruvec);
5415 mz->usage_in_excess = 0;
5416 mz->on_tree = false;
5419 memcg->nodeinfo[node] = pn;
5423 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5425 kfree(memcg->nodeinfo[node]);
5428 static struct mem_cgroup *mem_cgroup_alloc(void)
5430 struct mem_cgroup *memcg;
5433 size = sizeof(struct mem_cgroup);
5434 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
5436 memcg = kzalloc(size, GFP_KERNEL);
5440 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
5443 spin_lock_init(&memcg->pcp_counter_lock);
5452 * At destroying mem_cgroup, references from swap_cgroup can remain.
5453 * (scanning all at force_empty is too costly...)
5455 * Instead of clearing all references at force_empty, we remember
5456 * the number of reference from swap_cgroup and free mem_cgroup when
5457 * it goes down to 0.
5459 * Removal of cgroup itself succeeds regardless of refs from swap.
5462 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5466 mem_cgroup_remove_from_trees(memcg);
5469 free_mem_cgroup_per_zone_info(memcg, node);
5471 free_percpu(memcg->stat);
5474 * We need to make sure that (at least for now), the jump label
5475 * destruction code runs outside of the cgroup lock. This is because
5476 * get_online_cpus(), which is called from the static_branch update,
5477 * can't be called inside the cgroup_lock. cpusets are the ones
5478 * enforcing this dependency, so if they ever change, we might as well.
5480 * schedule_work() will guarantee this happens. Be careful if you need
5481 * to move this code around, and make sure it is outside
5484 disarm_static_keys(memcg);
5489 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
5491 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
5493 if (!memcg->res.parent)
5495 return mem_cgroup_from_res_counter(memcg->res.parent, res);
5497 EXPORT_SYMBOL(parent_mem_cgroup);
5499 static void __init mem_cgroup_soft_limit_tree_init(void)
5501 struct mem_cgroup_tree_per_node *rtpn;
5502 struct mem_cgroup_tree_per_zone *rtpz;
5503 int tmp, node, zone;
5505 for_each_node(node) {
5507 if (!node_state(node, N_NORMAL_MEMORY))
5509 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
5512 soft_limit_tree.rb_tree_per_node[node] = rtpn;
5514 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
5515 rtpz = &rtpn->rb_tree_per_zone[zone];
5516 rtpz->rb_root = RB_ROOT;
5517 spin_lock_init(&rtpz->lock);
5522 static struct cgroup_subsys_state * __ref
5523 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5525 struct mem_cgroup *memcg;
5526 long error = -ENOMEM;
5529 memcg = mem_cgroup_alloc();
5531 return ERR_PTR(error);
5534 if (alloc_mem_cgroup_per_zone_info(memcg, node))
5538 if (parent_css == NULL) {
5539 root_mem_cgroup = memcg;
5540 res_counter_init(&memcg->res, NULL);
5541 res_counter_init(&memcg->memsw, NULL);
5542 res_counter_init(&memcg->kmem, NULL);
5545 memcg->last_scanned_node = MAX_NUMNODES;
5546 INIT_LIST_HEAD(&memcg->oom_notify);
5547 memcg->move_charge_at_immigrate = 0;
5548 mutex_init(&memcg->thresholds_lock);
5549 spin_lock_init(&memcg->move_lock);
5550 vmpressure_init(&memcg->vmpressure);
5551 INIT_LIST_HEAD(&memcg->event_list);
5552 spin_lock_init(&memcg->event_list_lock);
5557 __mem_cgroup_free(memcg);
5558 return ERR_PTR(error);
5562 mem_cgroup_css_online(struct cgroup_subsys_state *css)
5564 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5565 struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
5568 if (css->id > MEM_CGROUP_ID_MAX)
5574 mutex_lock(&memcg_create_mutex);
5576 memcg->use_hierarchy = parent->use_hierarchy;
5577 memcg->oom_kill_disable = parent->oom_kill_disable;
5578 memcg->swappiness = mem_cgroup_swappiness(parent);
5580 if (parent->use_hierarchy) {
5581 res_counter_init(&memcg->res, &parent->res);
5582 res_counter_init(&memcg->memsw, &parent->memsw);
5583 res_counter_init(&memcg->kmem, &parent->kmem);
5586 * No need to take a reference to the parent because cgroup
5587 * core guarantees its existence.
5590 res_counter_init(&memcg->res, NULL);
5591 res_counter_init(&memcg->memsw, NULL);
5592 res_counter_init(&memcg->kmem, NULL);
5594 * Deeper hierachy with use_hierarchy == false doesn't make
5595 * much sense so let cgroup subsystem know about this
5596 * unfortunate state in our controller.
5598 if (parent != root_mem_cgroup)
5599 memory_cgrp_subsys.broken_hierarchy = true;
5601 mutex_unlock(&memcg_create_mutex);
5603 ret = memcg_init_kmem(memcg, &memory_cgrp_subsys);
5608 * Make sure the memcg is initialized: mem_cgroup_iter()
5609 * orders reading memcg->initialized against its callers
5610 * reading the memcg members.
5612 smp_store_release(&memcg->initialized, 1);
5618 * Announce all parents that a group from their hierarchy is gone.
5620 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
5622 struct mem_cgroup *parent = memcg;
5624 while ((parent = parent_mem_cgroup(parent)))
5625 mem_cgroup_iter_invalidate(parent);
5628 * if the root memcg is not hierarchical we have to check it
5631 if (!root_mem_cgroup->use_hierarchy)
5632 mem_cgroup_iter_invalidate(root_mem_cgroup);
5635 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5637 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5638 struct mem_cgroup_event *event, *tmp;
5639 struct cgroup_subsys_state *iter;
5642 * Unregister events and notify userspace.
5643 * Notify userspace about cgroup removing only after rmdir of cgroup
5644 * directory to avoid race between userspace and kernelspace.
5646 spin_lock(&memcg->event_list_lock);
5647 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
5648 list_del_init(&event->list);
5649 schedule_work(&event->remove);
5651 spin_unlock(&memcg->event_list_lock);
5653 kmem_cgroup_css_offline(memcg);
5655 mem_cgroup_invalidate_reclaim_iterators(memcg);
5658 * This requires that offlining is serialized. Right now that is
5659 * guaranteed because css_killed_work_fn() holds the cgroup_mutex.
5661 css_for_each_descendant_post(iter, css)
5662 mem_cgroup_reparent_charges(mem_cgroup_from_css(iter));
5664 memcg_unregister_all_caches(memcg);
5665 vmpressure_cleanup(&memcg->vmpressure);
5668 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5670 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5672 * XXX: css_offline() would be where we should reparent all
5673 * memory to prepare the cgroup for destruction. However,
5674 * memcg does not do css_tryget_online() and res_counter charging
5675 * under the same RCU lock region, which means that charging
5676 * could race with offlining. Offlining only happens to
5677 * cgroups with no tasks in them but charges can show up
5678 * without any tasks from the swapin path when the target
5679 * memcg is looked up from the swapout record and not from the
5680 * current task as it usually is. A race like this can leak
5681 * charges and put pages with stale cgroup pointers into
5685 * lookup_swap_cgroup_id()
5687 * mem_cgroup_lookup()
5688 * css_tryget_online()
5690 * disable css_tryget_online()
5693 * reparent_charges()
5694 * res_counter_charge()
5697 * pc->mem_cgroup = dead memcg
5700 * The bulk of the charges are still moved in offline_css() to
5701 * avoid pinning a lot of pages in case a long-term reference
5702 * like a swapout record is deferring the css_free() to long
5703 * after offlining. But this makes sure we catch any charges
5704 * made after offlining:
5706 mem_cgroup_reparent_charges(memcg);
5708 memcg_destroy_kmem(memcg);
5709 __mem_cgroup_free(memcg);
5713 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5714 * @css: the target css
5716 * Reset the states of the mem_cgroup associated with @css. This is
5717 * invoked when the userland requests disabling on the default hierarchy
5718 * but the memcg is pinned through dependency. The memcg should stop
5719 * applying policies and should revert to the vanilla state as it may be
5720 * made visible again.
5722 * The current implementation only resets the essential configurations.
5723 * This needs to be expanded to cover all the visible parts.
5725 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
5727 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5729 mem_cgroup_resize_limit(memcg, ULLONG_MAX);
5730 mem_cgroup_resize_memsw_limit(memcg, ULLONG_MAX);
5731 memcg_update_kmem_limit(memcg, ULLONG_MAX);
5732 res_counter_set_soft_limit(&memcg->res, ULLONG_MAX);
5736 /* Handlers for move charge at task migration. */
5737 static int mem_cgroup_do_precharge(unsigned long count)
5741 /* Try a single bulk charge without reclaim first */
5742 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
5744 mc.precharge += count;
5747 if (ret == -EINTR) {
5748 cancel_charge(root_mem_cgroup, count);
5752 /* Try charges one by one with reclaim */
5754 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
5756 * In case of failure, any residual charges against
5757 * mc.to will be dropped by mem_cgroup_clear_mc()
5758 * later on. However, cancel any charges that are
5759 * bypassed to root right away or they'll be lost.
5762 cancel_charge(root_mem_cgroup, 1);
5772 * get_mctgt_type - get target type of moving charge
5773 * @vma: the vma the pte to be checked belongs
5774 * @addr: the address corresponding to the pte to be checked
5775 * @ptent: the pte to be checked
5776 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5779 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5780 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5781 * move charge. if @target is not NULL, the page is stored in target->page
5782 * with extra refcnt got(Callers should handle it).
5783 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5784 * target for charge migration. if @target is not NULL, the entry is stored
5787 * Called with pte lock held.
5794 enum mc_target_type {
5800 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5801 unsigned long addr, pte_t ptent)
5803 struct page *page = vm_normal_page(vma, addr, ptent);
5805 if (!page || !page_mapped(page))
5807 if (PageAnon(page)) {
5808 /* we don't move shared anon */
5811 } else if (!move_file())
5812 /* we ignore mapcount for file pages */
5814 if (!get_page_unless_zero(page))
5821 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5822 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5824 struct page *page = NULL;
5825 swp_entry_t ent = pte_to_swp_entry(ptent);
5827 if (!move_anon() || non_swap_entry(ent))
5830 * Because lookup_swap_cache() updates some statistics counter,
5831 * we call find_get_page() with swapper_space directly.
5833 page = find_get_page(swap_address_space(ent), ent.val);
5834 if (do_swap_account)
5835 entry->val = ent.val;
5840 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5841 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5847 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5848 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5850 struct page *page = NULL;
5851 struct address_space *mapping;
5854 if (!vma->vm_file) /* anonymous vma */
5859 mapping = vma->vm_file->f_mapping;
5860 if (pte_none(ptent))
5861 pgoff = linear_page_index(vma, addr);
5862 else /* pte_file(ptent) is true */
5863 pgoff = pte_to_pgoff(ptent);
5865 /* page is moved even if it's not RSS of this task(page-faulted). */
5867 /* shmem/tmpfs may report page out on swap: account for that too. */
5868 if (shmem_mapping(mapping)) {
5869 page = find_get_entry(mapping, pgoff);
5870 if (radix_tree_exceptional_entry(page)) {
5871 swp_entry_t swp = radix_to_swp_entry(page);
5872 if (do_swap_account)
5874 page = find_get_page(swap_address_space(swp), swp.val);
5877 page = find_get_page(mapping, pgoff);
5879 page = find_get_page(mapping, pgoff);
5884 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5885 unsigned long addr, pte_t ptent, union mc_target *target)
5887 struct page *page = NULL;
5888 struct page_cgroup *pc;
5889 enum mc_target_type ret = MC_TARGET_NONE;
5890 swp_entry_t ent = { .val = 0 };
5892 if (pte_present(ptent))
5893 page = mc_handle_present_pte(vma, addr, ptent);
5894 else if (is_swap_pte(ptent))
5895 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5896 else if (pte_none(ptent) || pte_file(ptent))
5897 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5899 if (!page && !ent.val)
5902 pc = lookup_page_cgroup(page);
5904 * Do only loose check w/o serialization.
5905 * mem_cgroup_move_account() checks the pc is valid or
5906 * not under LRU exclusion.
5908 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5909 ret = MC_TARGET_PAGE;
5911 target->page = page;
5913 if (!ret || !target)
5916 /* There is a swap entry and a page doesn't exist or isn't charged */
5917 if (ent.val && !ret &&
5918 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5919 ret = MC_TARGET_SWAP;
5926 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5928 * We don't consider swapping or file mapped pages because THP does not
5929 * support them for now.
5930 * Caller should make sure that pmd_trans_huge(pmd) is true.
5932 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5933 unsigned long addr, pmd_t pmd, union mc_target *target)
5935 struct page *page = NULL;
5936 struct page_cgroup *pc;
5937 enum mc_target_type ret = MC_TARGET_NONE;
5939 page = pmd_page(pmd);
5940 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5943 pc = lookup_page_cgroup(page);
5944 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5945 ret = MC_TARGET_PAGE;
5948 target->page = page;
5954 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5955 unsigned long addr, pmd_t pmd, union mc_target *target)
5957 return MC_TARGET_NONE;
5961 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5962 unsigned long addr, unsigned long end,
5963 struct mm_walk *walk)
5965 struct vm_area_struct *vma = walk->private;
5969 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
5970 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5971 mc.precharge += HPAGE_PMD_NR;
5976 if (pmd_trans_unstable(pmd))
5978 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5979 for (; addr != end; pte++, addr += PAGE_SIZE)
5980 if (get_mctgt_type(vma, addr, *pte, NULL))
5981 mc.precharge++; /* increment precharge temporarily */
5982 pte_unmap_unlock(pte - 1, ptl);
5988 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5990 unsigned long precharge;
5991 struct vm_area_struct *vma;
5993 down_read(&mm->mmap_sem);
5994 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5995 struct mm_walk mem_cgroup_count_precharge_walk = {
5996 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6000 if (is_vm_hugetlb_page(vma))
6002 walk_page_range(vma->vm_start, vma->vm_end,
6003 &mem_cgroup_count_precharge_walk);
6005 up_read(&mm->mmap_sem);
6007 precharge = mc.precharge;
6013 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6015 unsigned long precharge = mem_cgroup_count_precharge(mm);
6017 VM_BUG_ON(mc.moving_task);
6018 mc.moving_task = current;
6019 return mem_cgroup_do_precharge(precharge);
6022 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6023 static void __mem_cgroup_clear_mc(void)
6025 struct mem_cgroup *from = mc.from;
6026 struct mem_cgroup *to = mc.to;
6029 /* we must uncharge all the leftover precharges from mc.to */
6031 cancel_charge(mc.to, mc.precharge);
6035 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6036 * we must uncharge here.
6038 if (mc.moved_charge) {
6039 cancel_charge(mc.from, mc.moved_charge);
6040 mc.moved_charge = 0;
6042 /* we must fixup refcnts and charges */
6043 if (mc.moved_swap) {
6044 /* uncharge swap account from the old cgroup */
6045 if (!mem_cgroup_is_root(mc.from))
6046 res_counter_uncharge(&mc.from->memsw,
6047 PAGE_SIZE * mc.moved_swap);
6049 for (i = 0; i < mc.moved_swap; i++)
6050 css_put(&mc.from->css);
6053 * we charged both to->res and to->memsw, so we should
6056 if (!mem_cgroup_is_root(mc.to))
6057 res_counter_uncharge(&mc.to->res,
6058 PAGE_SIZE * mc.moved_swap);
6059 /* we've already done css_get(mc.to) */
6062 memcg_oom_recover(from);
6063 memcg_oom_recover(to);
6064 wake_up_all(&mc.waitq);
6067 static void mem_cgroup_clear_mc(void)
6069 struct mem_cgroup *from = mc.from;
6072 * we must clear moving_task before waking up waiters at the end of
6075 mc.moving_task = NULL;
6076 __mem_cgroup_clear_mc();
6077 spin_lock(&mc.lock);
6080 spin_unlock(&mc.lock);
6081 mem_cgroup_end_move(from);
6084 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6085 struct cgroup_taskset *tset)
6087 struct task_struct *p = cgroup_taskset_first(tset);
6089 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6090 unsigned long move_charge_at_immigrate;
6093 * We are now commited to this value whatever it is. Changes in this
6094 * tunable will only affect upcoming migrations, not the current one.
6095 * So we need to save it, and keep it going.
6097 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6098 if (move_charge_at_immigrate) {
6099 struct mm_struct *mm;
6100 struct mem_cgroup *from = mem_cgroup_from_task(p);
6102 VM_BUG_ON(from == memcg);
6104 mm = get_task_mm(p);
6107 /* We move charges only when we move a owner of the mm */
6108 if (mm->owner == p) {
6111 VM_BUG_ON(mc.precharge);
6112 VM_BUG_ON(mc.moved_charge);
6113 VM_BUG_ON(mc.moved_swap);
6114 mem_cgroup_start_move(from);
6115 spin_lock(&mc.lock);
6118 mc.immigrate_flags = move_charge_at_immigrate;
6119 spin_unlock(&mc.lock);
6120 /* We set mc.moving_task later */
6122 ret = mem_cgroup_precharge_mc(mm);
6124 mem_cgroup_clear_mc();
6131 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6132 struct cgroup_taskset *tset)
6134 mem_cgroup_clear_mc();
6137 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6138 unsigned long addr, unsigned long end,
6139 struct mm_walk *walk)
6142 struct vm_area_struct *vma = walk->private;
6145 enum mc_target_type target_type;
6146 union mc_target target;
6148 struct page_cgroup *pc;
6151 * We don't take compound_lock() here but no race with splitting thp
6153 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6154 * under splitting, which means there's no concurrent thp split,
6155 * - if another thread runs into split_huge_page() just after we
6156 * entered this if-block, the thread must wait for page table lock
6157 * to be unlocked in __split_huge_page_splitting(), where the main
6158 * part of thp split is not executed yet.
6160 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
6161 if (mc.precharge < HPAGE_PMD_NR) {
6165 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6166 if (target_type == MC_TARGET_PAGE) {
6168 if (!isolate_lru_page(page)) {
6169 pc = lookup_page_cgroup(page);
6170 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6171 pc, mc.from, mc.to)) {
6172 mc.precharge -= HPAGE_PMD_NR;
6173 mc.moved_charge += HPAGE_PMD_NR;
6175 putback_lru_page(page);
6183 if (pmd_trans_unstable(pmd))
6186 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6187 for (; addr != end; addr += PAGE_SIZE) {
6188 pte_t ptent = *(pte++);
6194 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6195 case MC_TARGET_PAGE:
6197 if (isolate_lru_page(page))
6199 pc = lookup_page_cgroup(page);
6200 if (!mem_cgroup_move_account(page, 1, pc,
6203 /* we uncharge from mc.from later. */
6206 putback_lru_page(page);
6207 put: /* get_mctgt_type() gets the page */
6210 case MC_TARGET_SWAP:
6212 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6214 /* we fixup refcnts and charges later. */
6222 pte_unmap_unlock(pte - 1, ptl);
6227 * We have consumed all precharges we got in can_attach().
6228 * We try charge one by one, but don't do any additional
6229 * charges to mc.to if we have failed in charge once in attach()
6232 ret = mem_cgroup_do_precharge(1);
6240 static void mem_cgroup_move_charge(struct mm_struct *mm)
6242 struct vm_area_struct *vma;
6244 lru_add_drain_all();
6246 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6248 * Someone who are holding the mmap_sem might be waiting in
6249 * waitq. So we cancel all extra charges, wake up all waiters,
6250 * and retry. Because we cancel precharges, we might not be able
6251 * to move enough charges, but moving charge is a best-effort
6252 * feature anyway, so it wouldn't be a big problem.
6254 __mem_cgroup_clear_mc();
6258 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6260 struct mm_walk mem_cgroup_move_charge_walk = {
6261 .pmd_entry = mem_cgroup_move_charge_pte_range,
6265 if (is_vm_hugetlb_page(vma))
6267 ret = walk_page_range(vma->vm_start, vma->vm_end,
6268 &mem_cgroup_move_charge_walk);
6271 * means we have consumed all precharges and failed in
6272 * doing additional charge. Just abandon here.
6276 up_read(&mm->mmap_sem);
6279 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6280 struct cgroup_taskset *tset)
6282 struct task_struct *p = cgroup_taskset_first(tset);
6283 struct mm_struct *mm = get_task_mm(p);
6287 mem_cgroup_move_charge(mm);
6291 mem_cgroup_clear_mc();
6293 #else /* !CONFIG_MMU */
6294 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6295 struct cgroup_taskset *tset)
6299 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6300 struct cgroup_taskset *tset)
6303 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6304 struct cgroup_taskset *tset)
6310 * Cgroup retains root cgroups across [un]mount cycles making it necessary
6311 * to verify whether we're attached to the default hierarchy on each mount
6314 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
6317 * use_hierarchy is forced on the default hierarchy. cgroup core
6318 * guarantees that @root doesn't have any children, so turning it
6319 * on for the root memcg is enough.
6321 if (cgroup_on_dfl(root_css->cgroup))
6322 mem_cgroup_from_css(root_css)->use_hierarchy = true;
6325 struct cgroup_subsys memory_cgrp_subsys = {
6326 .css_alloc = mem_cgroup_css_alloc,
6327 .css_online = mem_cgroup_css_online,
6328 .css_offline = mem_cgroup_css_offline,
6329 .css_free = mem_cgroup_css_free,
6330 .css_reset = mem_cgroup_css_reset,
6331 .can_attach = mem_cgroup_can_attach,
6332 .cancel_attach = mem_cgroup_cancel_attach,
6333 .attach = mem_cgroup_move_task,
6334 .bind = mem_cgroup_bind,
6335 .legacy_cftypes = mem_cgroup_files,
6339 #ifdef CONFIG_MEMCG_SWAP
6340 static int __init enable_swap_account(char *s)
6342 if (!strcmp(s, "1"))
6343 really_do_swap_account = 1;
6344 else if (!strcmp(s, "0"))
6345 really_do_swap_account = 0;
6348 __setup("swapaccount=", enable_swap_account);
6350 static void __init memsw_file_init(void)
6352 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
6353 memsw_cgroup_files));
6356 static void __init enable_swap_cgroup(void)
6358 if (!mem_cgroup_disabled() && really_do_swap_account) {
6359 do_swap_account = 1;
6365 static void __init enable_swap_cgroup(void)
6370 #ifdef CONFIG_MEMCG_SWAP
6372 * mem_cgroup_swapout - transfer a memsw charge to swap
6373 * @page: page whose memsw charge to transfer
6374 * @entry: swap entry to move the charge to
6376 * Transfer the memsw charge of @page to @entry.
6378 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
6380 struct page_cgroup *pc;
6381 unsigned short oldid;
6383 VM_BUG_ON_PAGE(PageLRU(page), page);
6384 VM_BUG_ON_PAGE(page_count(page), page);
6386 if (!do_swap_account)
6389 pc = lookup_page_cgroup(page);
6391 /* Readahead page, never charged */
6392 if (!PageCgroupUsed(pc))
6395 VM_BUG_ON_PAGE(!(pc->flags & PCG_MEMSW), page);
6397 oldid = swap_cgroup_record(entry, mem_cgroup_id(pc->mem_cgroup));
6398 VM_BUG_ON_PAGE(oldid, page);
6400 pc->flags &= ~PCG_MEMSW;
6401 css_get(&pc->mem_cgroup->css);
6402 mem_cgroup_swap_statistics(pc->mem_cgroup, true);
6406 * mem_cgroup_uncharge_swap - uncharge a swap entry
6407 * @entry: swap entry to uncharge
6409 * Drop the memsw charge associated with @entry.
6411 void mem_cgroup_uncharge_swap(swp_entry_t entry)
6413 struct mem_cgroup *memcg;
6416 if (!do_swap_account)
6419 id = swap_cgroup_record(entry, 0);
6421 memcg = mem_cgroup_lookup(id);
6423 if (!mem_cgroup_is_root(memcg))
6424 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
6425 mem_cgroup_swap_statistics(memcg, false);
6426 css_put(&memcg->css);
6433 * mem_cgroup_try_charge - try charging a page
6434 * @page: page to charge
6435 * @mm: mm context of the victim
6436 * @gfp_mask: reclaim mode
6437 * @memcgp: charged memcg return
6439 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6440 * pages according to @gfp_mask if necessary.
6442 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
6443 * Otherwise, an error code is returned.
6445 * After page->mapping has been set up, the caller must finalize the
6446 * charge with mem_cgroup_commit_charge(). Or abort the transaction
6447 * with mem_cgroup_cancel_charge() in case page instantiation fails.
6449 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
6450 gfp_t gfp_mask, struct mem_cgroup **memcgp)
6452 struct mem_cgroup *memcg = NULL;
6453 unsigned int nr_pages = 1;
6456 if (mem_cgroup_disabled())
6459 if (PageSwapCache(page)) {
6460 struct page_cgroup *pc = lookup_page_cgroup(page);
6462 * Every swap fault against a single page tries to charge the
6463 * page, bail as early as possible. shmem_unuse() encounters
6464 * already charged pages, too. The USED bit is protected by
6465 * the page lock, which serializes swap cache removal, which
6466 * in turn serializes uncharging.
6468 if (PageCgroupUsed(pc))
6472 if (PageTransHuge(page)) {
6473 nr_pages <<= compound_order(page);
6474 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
6477 if (do_swap_account && PageSwapCache(page))
6478 memcg = try_get_mem_cgroup_from_page(page);
6480 memcg = get_mem_cgroup_from_mm(mm);
6482 ret = try_charge(memcg, gfp_mask, nr_pages);
6484 css_put(&memcg->css);
6486 if (ret == -EINTR) {
6487 memcg = root_mem_cgroup;
6496 * mem_cgroup_commit_charge - commit a page charge
6497 * @page: page to charge
6498 * @memcg: memcg to charge the page to
6499 * @lrucare: page might be on LRU already
6501 * Finalize a charge transaction started by mem_cgroup_try_charge(),
6502 * after page->mapping has been set up. This must happen atomically
6503 * as part of the page instantiation, i.e. under the page table lock
6504 * for anonymous pages, under the page lock for page and swap cache.
6506 * In addition, the page must not be on the LRU during the commit, to
6507 * prevent racing with task migration. If it might be, use @lrucare.
6509 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
6511 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
6514 unsigned int nr_pages = 1;
6516 VM_BUG_ON_PAGE(!page->mapping, page);
6517 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
6519 if (mem_cgroup_disabled())
6522 * Swap faults will attempt to charge the same page multiple
6523 * times. But reuse_swap_page() might have removed the page
6524 * from swapcache already, so we can't check PageSwapCache().
6529 commit_charge(page, memcg, lrucare);
6531 if (PageTransHuge(page)) {
6532 nr_pages <<= compound_order(page);
6533 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
6536 local_irq_disable();
6537 mem_cgroup_charge_statistics(memcg, page, nr_pages);
6538 memcg_check_events(memcg, page);
6541 if (do_swap_account && PageSwapCache(page)) {
6542 swp_entry_t entry = { .val = page_private(page) };
6544 * The swap entry might not get freed for a long time,
6545 * let's not wait for it. The page already received a
6546 * memory+swap charge, drop the swap entry duplicate.
6548 mem_cgroup_uncharge_swap(entry);
6553 * mem_cgroup_cancel_charge - cancel a page charge
6554 * @page: page to charge
6555 * @memcg: memcg to charge the page to
6557 * Cancel a charge transaction started by mem_cgroup_try_charge().
6559 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg)
6561 unsigned int nr_pages = 1;
6563 if (mem_cgroup_disabled())
6566 * Swap faults will attempt to charge the same page multiple
6567 * times. But reuse_swap_page() might have removed the page
6568 * from swapcache already, so we can't check PageSwapCache().
6573 if (PageTransHuge(page)) {
6574 nr_pages <<= compound_order(page);
6575 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
6578 cancel_charge(memcg, nr_pages);
6581 static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
6582 unsigned long nr_mem, unsigned long nr_memsw,
6583 unsigned long nr_anon, unsigned long nr_file,
6584 unsigned long nr_huge, struct page *dummy_page)
6586 unsigned long flags;
6588 if (!mem_cgroup_is_root(memcg)) {
6590 res_counter_uncharge(&memcg->res,
6591 nr_mem * PAGE_SIZE);
6593 res_counter_uncharge(&memcg->memsw,
6594 nr_memsw * PAGE_SIZE);
6595 memcg_oom_recover(memcg);
6598 local_irq_save(flags);
6599 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
6600 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
6601 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
6602 __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
6603 __this_cpu_add(memcg->stat->nr_page_events, nr_anon + nr_file);
6604 memcg_check_events(memcg, dummy_page);
6605 local_irq_restore(flags);
6608 static void uncharge_list(struct list_head *page_list)
6610 struct mem_cgroup *memcg = NULL;
6611 unsigned long nr_memsw = 0;
6612 unsigned long nr_anon = 0;
6613 unsigned long nr_file = 0;
6614 unsigned long nr_huge = 0;
6615 unsigned long pgpgout = 0;
6616 unsigned long nr_mem = 0;
6617 struct list_head *next;
6620 next = page_list->next;
6622 unsigned int nr_pages = 1;
6623 struct page_cgroup *pc;
6625 page = list_entry(next, struct page, lru);
6626 next = page->lru.next;
6628 VM_BUG_ON_PAGE(PageLRU(page), page);
6629 VM_BUG_ON_PAGE(page_count(page), page);
6631 pc = lookup_page_cgroup(page);
6632 if (!PageCgroupUsed(pc))
6636 * Nobody should be changing or seriously looking at
6637 * pc->mem_cgroup and pc->flags at this point, we have
6638 * fully exclusive access to the page.
6641 if (memcg != pc->mem_cgroup) {
6643 uncharge_batch(memcg, pgpgout, nr_mem, nr_memsw,
6644 nr_anon, nr_file, nr_huge, page);
6645 pgpgout = nr_mem = nr_memsw = 0;
6646 nr_anon = nr_file = nr_huge = 0;
6648 memcg = pc->mem_cgroup;
6651 if (PageTransHuge(page)) {
6652 nr_pages <<= compound_order(page);
6653 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
6654 nr_huge += nr_pages;
6658 nr_anon += nr_pages;
6660 nr_file += nr_pages;
6662 if (pc->flags & PCG_MEM)
6664 if (pc->flags & PCG_MEMSW)
6665 nr_memsw += nr_pages;
6669 } while (next != page_list);
6672 uncharge_batch(memcg, pgpgout, nr_mem, nr_memsw,
6673 nr_anon, nr_file, nr_huge, page);
6677 * mem_cgroup_uncharge - uncharge a page
6678 * @page: page to uncharge
6680 * Uncharge a page previously charged with mem_cgroup_try_charge() and
6681 * mem_cgroup_commit_charge().
6683 void mem_cgroup_uncharge(struct page *page)
6685 struct page_cgroup *pc;
6687 if (mem_cgroup_disabled())
6690 /* Don't touch page->lru of any random page, pre-check: */
6691 pc = lookup_page_cgroup(page);
6692 if (!PageCgroupUsed(pc))
6695 INIT_LIST_HEAD(&page->lru);
6696 uncharge_list(&page->lru);
6700 * mem_cgroup_uncharge_list - uncharge a list of page
6701 * @page_list: list of pages to uncharge
6703 * Uncharge a list of pages previously charged with
6704 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
6706 void mem_cgroup_uncharge_list(struct list_head *page_list)
6708 if (mem_cgroup_disabled())
6711 if (!list_empty(page_list))
6712 uncharge_list(page_list);
6716 * mem_cgroup_migrate - migrate a charge to another page
6717 * @oldpage: currently charged page
6718 * @newpage: page to transfer the charge to
6719 * @lrucare: both pages might be on the LRU already
6721 * Migrate the charge from @oldpage to @newpage.
6723 * Both pages must be locked, @newpage->mapping must be set up.
6725 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage,
6728 struct page_cgroup *pc;
6731 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
6732 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
6733 VM_BUG_ON_PAGE(!lrucare && PageLRU(oldpage), oldpage);
6734 VM_BUG_ON_PAGE(!lrucare && PageLRU(newpage), newpage);
6735 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
6736 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
6739 if (mem_cgroup_disabled())
6742 /* Page cache replacement: new page already charged? */
6743 pc = lookup_page_cgroup(newpage);
6744 if (PageCgroupUsed(pc))
6747 /* Re-entrant migration: old page already uncharged? */
6748 pc = lookup_page_cgroup(oldpage);
6749 if (!PageCgroupUsed(pc))
6752 VM_BUG_ON_PAGE(!(pc->flags & PCG_MEM), oldpage);
6753 VM_BUG_ON_PAGE(do_swap_account && !(pc->flags & PCG_MEMSW), oldpage);
6756 lock_page_lru(oldpage, &isolated);
6761 unlock_page_lru(oldpage, isolated);
6763 commit_charge(newpage, pc->mem_cgroup, lrucare);
6767 * subsys_initcall() for memory controller.
6769 * Some parts like hotcpu_notifier() have to be initialized from this context
6770 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6771 * everything that doesn't depend on a specific mem_cgroup structure should
6772 * be initialized from here.
6774 static int __init mem_cgroup_init(void)
6776 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6777 enable_swap_cgroup();
6778 mem_cgroup_soft_limit_tree_init();
6782 subsys_initcall(mem_cgroup_init);