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/sort.h>
50 #include <linux/seq_file.h>
51 #include <linux/vmalloc.h>
52 #include <linux/mm_inline.h>
53 #include <linux/page_cgroup.h>
54 #include <linux/cpu.h>
55 #include <linux/oom.h>
59 #include <net/tcp_memcontrol.h>
61 #include <asm/uaccess.h>
63 #include <trace/events/vmscan.h>
65 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
66 EXPORT_SYMBOL(mem_cgroup_subsys);
68 #define MEM_CGROUP_RECLAIM_RETRIES 5
69 static struct mem_cgroup *root_mem_cgroup __read_mostly;
71 #ifdef CONFIG_MEMCG_SWAP
72 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
73 int do_swap_account __read_mostly;
75 /* for remember boot option*/
76 #ifdef CONFIG_MEMCG_SWAP_ENABLED
77 static int really_do_swap_account __initdata = 1;
79 static int really_do_swap_account __initdata = 0;
83 #define do_swap_account 0
88 * Statistics for memory cgroup.
90 enum mem_cgroup_stat_index {
92 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
94 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
95 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
96 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
97 MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
98 MEM_CGROUP_STAT_NSTATS,
101 static const char * const mem_cgroup_stat_names[] = {
108 enum mem_cgroup_events_index {
109 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
110 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
111 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
112 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
113 MEM_CGROUP_EVENTS_NSTATS,
116 static const char * const mem_cgroup_events_names[] = {
123 static const char * const mem_cgroup_lru_names[] = {
132 * Per memcg event counter is incremented at every pagein/pageout. With THP,
133 * it will be incremated by the number of pages. This counter is used for
134 * for trigger some periodic events. This is straightforward and better
135 * than using jiffies etc. to handle periodic memcg event.
137 enum mem_cgroup_events_target {
138 MEM_CGROUP_TARGET_THRESH,
139 MEM_CGROUP_TARGET_SOFTLIMIT,
140 MEM_CGROUP_TARGET_NUMAINFO,
143 #define THRESHOLDS_EVENTS_TARGET 128
144 #define SOFTLIMIT_EVENTS_TARGET 1024
145 #define NUMAINFO_EVENTS_TARGET 1024
147 struct mem_cgroup_stat_cpu {
148 long count[MEM_CGROUP_STAT_NSTATS];
149 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
150 unsigned long nr_page_events;
151 unsigned long targets[MEM_CGROUP_NTARGETS];
154 struct mem_cgroup_reclaim_iter {
155 /* css_id of the last scanned hierarchy member */
157 /* scan generation, increased every round-trip */
158 unsigned int generation;
162 * per-zone information in memory controller.
164 struct mem_cgroup_per_zone {
165 struct lruvec lruvec;
166 unsigned long lru_size[NR_LRU_LISTS];
168 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
170 struct rb_node tree_node; /* RB tree node */
171 unsigned long long usage_in_excess;/* Set to the value by which */
172 /* the soft limit is exceeded*/
174 struct mem_cgroup *memcg; /* Back pointer, we cannot */
175 /* use container_of */
178 struct mem_cgroup_per_node {
179 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
182 struct mem_cgroup_lru_info {
183 struct mem_cgroup_per_node *nodeinfo[0];
187 * Cgroups above their limits are maintained in a RB-Tree, independent of
188 * their hierarchy representation
191 struct mem_cgroup_tree_per_zone {
192 struct rb_root rb_root;
196 struct mem_cgroup_tree_per_node {
197 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
200 struct mem_cgroup_tree {
201 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
204 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
206 struct mem_cgroup_threshold {
207 struct eventfd_ctx *eventfd;
212 struct mem_cgroup_threshold_ary {
213 /* An array index points to threshold just below or equal to usage. */
214 int current_threshold;
215 /* Size of entries[] */
217 /* Array of thresholds */
218 struct mem_cgroup_threshold entries[0];
221 struct mem_cgroup_thresholds {
222 /* Primary thresholds array */
223 struct mem_cgroup_threshold_ary *primary;
225 * Spare threshold array.
226 * This is needed to make mem_cgroup_unregister_event() "never fail".
227 * It must be able to store at least primary->size - 1 entries.
229 struct mem_cgroup_threshold_ary *spare;
233 struct mem_cgroup_eventfd_list {
234 struct list_head list;
235 struct eventfd_ctx *eventfd;
238 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
239 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
242 * The memory controller data structure. The memory controller controls both
243 * page cache and RSS per cgroup. We would eventually like to provide
244 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
245 * to help the administrator determine what knobs to tune.
247 * TODO: Add a water mark for the memory controller. Reclaim will begin when
248 * we hit the water mark. May be even add a low water mark, such that
249 * no reclaim occurs from a cgroup at it's low water mark, this is
250 * a feature that will be implemented much later in the future.
253 struct cgroup_subsys_state css;
255 * the counter to account for memory usage
257 struct res_counter res;
261 * the counter to account for mem+swap usage.
263 struct res_counter memsw;
266 * rcu_freeing is used only when freeing struct mem_cgroup,
267 * so put it into a union to avoid wasting more memory.
268 * It must be disjoint from the css field. It could be
269 * in a union with the res field, but res plays a much
270 * larger part in mem_cgroup life than memsw, and might
271 * be of interest, even at time of free, when debugging.
272 * So share rcu_head with the less interesting memsw.
274 struct rcu_head rcu_freeing;
276 * We also need some space for a worker in deferred freeing.
277 * By the time we call it, rcu_freeing is no longer in use.
279 struct work_struct work_freeing;
283 * the counter to account for kernel memory usage.
285 struct res_counter kmem;
287 * Should the accounting and control be hierarchical, per subtree?
290 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
298 /* OOM-Killer disable */
299 int oom_kill_disable;
301 /* set when res.limit == memsw.limit */
302 bool memsw_is_minimum;
304 /* protect arrays of thresholds */
305 struct mutex thresholds_lock;
307 /* thresholds for memory usage. RCU-protected */
308 struct mem_cgroup_thresholds thresholds;
310 /* thresholds for mem+swap usage. RCU-protected */
311 struct mem_cgroup_thresholds memsw_thresholds;
313 /* For oom notifier event fd */
314 struct list_head oom_notify;
317 * Should we move charges of a task when a task is moved into this
318 * mem_cgroup ? And what type of charges should we move ?
320 unsigned long move_charge_at_immigrate;
322 * set > 0 if pages under this cgroup are moving to other cgroup.
324 atomic_t moving_account;
325 /* taken only while moving_account > 0 */
326 spinlock_t move_lock;
330 struct mem_cgroup_stat_cpu __percpu *stat;
332 * used when a cpu is offlined or other synchronizations
333 * See mem_cgroup_read_stat().
335 struct mem_cgroup_stat_cpu nocpu_base;
336 spinlock_t pcp_counter_lock;
338 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
339 struct tcp_memcontrol tcp_mem;
341 #if defined(CONFIG_MEMCG_KMEM)
342 /* analogous to slab_common's slab_caches list. per-memcg */
343 struct list_head memcg_slab_caches;
344 /* Not a spinlock, we can take a lot of time walking the list */
345 struct mutex slab_caches_mutex;
346 /* Index in the kmem_cache->memcg_params->memcg_caches array */
350 int last_scanned_node;
352 nodemask_t scan_nodes;
353 atomic_t numainfo_events;
354 atomic_t numainfo_updating;
357 * Per cgroup active and inactive list, similar to the
358 * per zone LRU lists.
360 * WARNING: This has to be the last element of the struct. Don't
361 * add new fields after this point.
363 struct mem_cgroup_lru_info info;
366 static size_t memcg_size(void)
368 return sizeof(struct mem_cgroup) +
369 nr_node_ids * sizeof(struct mem_cgroup_per_node);
372 /* internal only representation about the status of kmem accounting. */
374 KMEM_ACCOUNTED_ACTIVE = 0, /* accounted by this cgroup itself */
375 KMEM_ACCOUNTED_ACTIVATED, /* static key enabled. */
376 KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
379 /* We account when limit is on, but only after call sites are patched */
380 #define KMEM_ACCOUNTED_MASK \
381 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
383 #ifdef CONFIG_MEMCG_KMEM
384 static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
386 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
389 static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
391 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
394 static void memcg_kmem_set_activated(struct mem_cgroup *memcg)
396 set_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags);
399 static void memcg_kmem_clear_activated(struct mem_cgroup *memcg)
401 clear_bit(KMEM_ACCOUNTED_ACTIVATED, &memcg->kmem_account_flags);
404 static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
406 if (test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags))
407 set_bit(KMEM_ACCOUNTED_DEAD, &memcg->kmem_account_flags);
410 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup *memcg)
412 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD,
413 &memcg->kmem_account_flags);
417 /* Stuffs for move charges at task migration. */
419 * Types of charges to be moved. "move_charge_at_immitgrate" and
420 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
423 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
424 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
428 /* "mc" and its members are protected by cgroup_mutex */
429 static struct move_charge_struct {
430 spinlock_t lock; /* for from, to */
431 struct mem_cgroup *from;
432 struct mem_cgroup *to;
433 unsigned long immigrate_flags;
434 unsigned long precharge;
435 unsigned long moved_charge;
436 unsigned long moved_swap;
437 struct task_struct *moving_task; /* a task moving charges */
438 wait_queue_head_t waitq; /* a waitq for other context */
440 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
441 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
444 static bool move_anon(void)
446 return test_bit(MOVE_CHARGE_TYPE_ANON, &mc.immigrate_flags);
449 static bool move_file(void)
451 return test_bit(MOVE_CHARGE_TYPE_FILE, &mc.immigrate_flags);
455 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
456 * limit reclaim to prevent infinite loops, if they ever occur.
458 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
459 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
462 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
463 MEM_CGROUP_CHARGE_TYPE_ANON,
464 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
465 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
469 /* for encoding cft->private value on file */
477 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
478 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
479 #define MEMFILE_ATTR(val) ((val) & 0xffff)
480 /* Used for OOM nofiier */
481 #define OOM_CONTROL (0)
484 * Reclaim flags for mem_cgroup_hierarchical_reclaim
486 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
487 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
488 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
489 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
492 * The memcg_create_mutex will be held whenever a new cgroup is created.
493 * As a consequence, any change that needs to protect against new child cgroups
494 * appearing has to hold it as well.
496 static DEFINE_MUTEX(memcg_create_mutex);
498 static void mem_cgroup_get(struct mem_cgroup *memcg);
499 static void mem_cgroup_put(struct mem_cgroup *memcg);
502 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
504 return container_of(s, struct mem_cgroup, css);
507 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
509 return (memcg == root_mem_cgroup);
512 /* Writing them here to avoid exposing memcg's inner layout */
513 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
515 void sock_update_memcg(struct sock *sk)
517 if (mem_cgroup_sockets_enabled) {
518 struct mem_cgroup *memcg;
519 struct cg_proto *cg_proto;
521 BUG_ON(!sk->sk_prot->proto_cgroup);
523 /* Socket cloning can throw us here with sk_cgrp already
524 * filled. It won't however, necessarily happen from
525 * process context. So the test for root memcg given
526 * the current task's memcg won't help us in this case.
528 * Respecting the original socket's memcg is a better
529 * decision in this case.
532 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
533 mem_cgroup_get(sk->sk_cgrp->memcg);
538 memcg = mem_cgroup_from_task(current);
539 cg_proto = sk->sk_prot->proto_cgroup(memcg);
540 if (!mem_cgroup_is_root(memcg) && memcg_proto_active(cg_proto)) {
541 mem_cgroup_get(memcg);
542 sk->sk_cgrp = cg_proto;
547 EXPORT_SYMBOL(sock_update_memcg);
549 void sock_release_memcg(struct sock *sk)
551 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
552 struct mem_cgroup *memcg;
553 WARN_ON(!sk->sk_cgrp->memcg);
554 memcg = sk->sk_cgrp->memcg;
555 mem_cgroup_put(memcg);
559 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
561 if (!memcg || mem_cgroup_is_root(memcg))
564 return &memcg->tcp_mem.cg_proto;
566 EXPORT_SYMBOL(tcp_proto_cgroup);
568 static void disarm_sock_keys(struct mem_cgroup *memcg)
570 if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto))
572 static_key_slow_dec(&memcg_socket_limit_enabled);
575 static void disarm_sock_keys(struct mem_cgroup *memcg)
580 #ifdef CONFIG_MEMCG_KMEM
582 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
583 * There are two main reasons for not using the css_id for this:
584 * 1) this works better in sparse environments, where we have a lot of memcgs,
585 * but only a few kmem-limited. Or also, if we have, for instance, 200
586 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
587 * 200 entry array for that.
589 * 2) In order not to violate the cgroup API, we would like to do all memory
590 * allocation in ->create(). At that point, we haven't yet allocated the
591 * css_id. Having a separate index prevents us from messing with the cgroup
594 * The current size of the caches array is stored in
595 * memcg_limited_groups_array_size. It will double each time we have to
598 static DEFINE_IDA(kmem_limited_groups);
599 int memcg_limited_groups_array_size;
602 * MIN_SIZE is different than 1, because we would like to avoid going through
603 * the alloc/free process all the time. In a small machine, 4 kmem-limited
604 * cgroups is a reasonable guess. In the future, it could be a parameter or
605 * tunable, but that is strictly not necessary.
607 * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get
608 * this constant directly from cgroup, but it is understandable that this is
609 * better kept as an internal representation in cgroup.c. In any case, the
610 * css_id space is not getting any smaller, and we don't have to necessarily
611 * increase ours as well if it increases.
613 #define MEMCG_CACHES_MIN_SIZE 4
614 #define MEMCG_CACHES_MAX_SIZE 65535
617 * A lot of the calls to the cache allocation functions are expected to be
618 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
619 * conditional to this static branch, we'll have to allow modules that does
620 * kmem_cache_alloc and the such to see this symbol as well
622 struct static_key memcg_kmem_enabled_key;
623 EXPORT_SYMBOL(memcg_kmem_enabled_key);
625 static void disarm_kmem_keys(struct mem_cgroup *memcg)
627 if (memcg_kmem_is_active(memcg)) {
628 static_key_slow_dec(&memcg_kmem_enabled_key);
629 ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
632 * This check can't live in kmem destruction function,
633 * since the charges will outlive the cgroup
635 WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
638 static void disarm_kmem_keys(struct mem_cgroup *memcg)
641 #endif /* CONFIG_MEMCG_KMEM */
643 static void disarm_static_keys(struct mem_cgroup *memcg)
645 disarm_sock_keys(memcg);
646 disarm_kmem_keys(memcg);
649 static void drain_all_stock_async(struct mem_cgroup *memcg);
651 static struct mem_cgroup_per_zone *
652 mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
654 VM_BUG_ON((unsigned)nid >= nr_node_ids);
655 return &memcg->info.nodeinfo[nid]->zoneinfo[zid];
658 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
663 static struct mem_cgroup_per_zone *
664 page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
666 int nid = page_to_nid(page);
667 int zid = page_zonenum(page);
669 return mem_cgroup_zoneinfo(memcg, nid, zid);
672 static struct mem_cgroup_tree_per_zone *
673 soft_limit_tree_node_zone(int nid, int zid)
675 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
678 static struct mem_cgroup_tree_per_zone *
679 soft_limit_tree_from_page(struct page *page)
681 int nid = page_to_nid(page);
682 int zid = page_zonenum(page);
684 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
688 __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
689 struct mem_cgroup_per_zone *mz,
690 struct mem_cgroup_tree_per_zone *mctz,
691 unsigned long long new_usage_in_excess)
693 struct rb_node **p = &mctz->rb_root.rb_node;
694 struct rb_node *parent = NULL;
695 struct mem_cgroup_per_zone *mz_node;
700 mz->usage_in_excess = new_usage_in_excess;
701 if (!mz->usage_in_excess)
705 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
707 if (mz->usage_in_excess < mz_node->usage_in_excess)
710 * We can't avoid mem cgroups that are over their soft
711 * limit by the same amount
713 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
716 rb_link_node(&mz->tree_node, parent, p);
717 rb_insert_color(&mz->tree_node, &mctz->rb_root);
722 __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
723 struct mem_cgroup_per_zone *mz,
724 struct mem_cgroup_tree_per_zone *mctz)
728 rb_erase(&mz->tree_node, &mctz->rb_root);
733 mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
734 struct mem_cgroup_per_zone *mz,
735 struct mem_cgroup_tree_per_zone *mctz)
737 spin_lock(&mctz->lock);
738 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
739 spin_unlock(&mctz->lock);
743 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
745 unsigned long long excess;
746 struct mem_cgroup_per_zone *mz;
747 struct mem_cgroup_tree_per_zone *mctz;
748 int nid = page_to_nid(page);
749 int zid = page_zonenum(page);
750 mctz = soft_limit_tree_from_page(page);
753 * Necessary to update all ancestors when hierarchy is used.
754 * because their event counter is not touched.
756 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
757 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
758 excess = res_counter_soft_limit_excess(&memcg->res);
760 * We have to update the tree if mz is on RB-tree or
761 * mem is over its softlimit.
763 if (excess || mz->on_tree) {
764 spin_lock(&mctz->lock);
765 /* if on-tree, remove it */
767 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
769 * Insert again. mz->usage_in_excess will be updated.
770 * If excess is 0, no tree ops.
772 __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
773 spin_unlock(&mctz->lock);
778 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
781 struct mem_cgroup_per_zone *mz;
782 struct mem_cgroup_tree_per_zone *mctz;
784 for_each_node(node) {
785 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
786 mz = mem_cgroup_zoneinfo(memcg, node, zone);
787 mctz = soft_limit_tree_node_zone(node, zone);
788 mem_cgroup_remove_exceeded(memcg, mz, mctz);
793 static struct mem_cgroup_per_zone *
794 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
796 struct rb_node *rightmost = NULL;
797 struct mem_cgroup_per_zone *mz;
801 rightmost = rb_last(&mctz->rb_root);
803 goto done; /* Nothing to reclaim from */
805 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
807 * Remove the node now but someone else can add it back,
808 * we will to add it back at the end of reclaim to its correct
809 * position in the tree.
811 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
812 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
813 !css_tryget(&mz->memcg->css))
819 static struct mem_cgroup_per_zone *
820 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
822 struct mem_cgroup_per_zone *mz;
824 spin_lock(&mctz->lock);
825 mz = __mem_cgroup_largest_soft_limit_node(mctz);
826 spin_unlock(&mctz->lock);
831 * Implementation Note: reading percpu statistics for memcg.
833 * Both of vmstat[] and percpu_counter has threshold and do periodic
834 * synchronization to implement "quick" read. There are trade-off between
835 * reading cost and precision of value. Then, we may have a chance to implement
836 * a periodic synchronizion of counter in memcg's counter.
838 * But this _read() function is used for user interface now. The user accounts
839 * memory usage by memory cgroup and he _always_ requires exact value because
840 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
841 * have to visit all online cpus and make sum. So, for now, unnecessary
842 * synchronization is not implemented. (just implemented for cpu hotplug)
844 * If there are kernel internal actions which can make use of some not-exact
845 * value, and reading all cpu value can be performance bottleneck in some
846 * common workload, threashold and synchonization as vmstat[] should be
849 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
850 enum mem_cgroup_stat_index idx)
856 for_each_online_cpu(cpu)
857 val += per_cpu(memcg->stat->count[idx], cpu);
858 #ifdef CONFIG_HOTPLUG_CPU
859 spin_lock(&memcg->pcp_counter_lock);
860 val += memcg->nocpu_base.count[idx];
861 spin_unlock(&memcg->pcp_counter_lock);
867 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
870 int val = (charge) ? 1 : -1;
871 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
874 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
875 enum mem_cgroup_events_index idx)
877 unsigned long val = 0;
880 for_each_online_cpu(cpu)
881 val += per_cpu(memcg->stat->events[idx], cpu);
882 #ifdef CONFIG_HOTPLUG_CPU
883 spin_lock(&memcg->pcp_counter_lock);
884 val += memcg->nocpu_base.events[idx];
885 spin_unlock(&memcg->pcp_counter_lock);
890 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
891 bool anon, int nr_pages)
896 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
897 * counted as CACHE even if it's on ANON LRU.
900 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
903 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
906 /* pagein of a big page is an event. So, ignore page size */
908 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
910 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
911 nr_pages = -nr_pages; /* for event */
914 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
920 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
922 struct mem_cgroup_per_zone *mz;
924 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
925 return mz->lru_size[lru];
929 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
930 unsigned int lru_mask)
932 struct mem_cgroup_per_zone *mz;
934 unsigned long ret = 0;
936 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
939 if (BIT(lru) & lru_mask)
940 ret += mz->lru_size[lru];
946 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
947 int nid, unsigned int lru_mask)
952 for (zid = 0; zid < MAX_NR_ZONES; zid++)
953 total += mem_cgroup_zone_nr_lru_pages(memcg,
959 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
960 unsigned int lru_mask)
965 for_each_node_state(nid, N_MEMORY)
966 total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
970 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
971 enum mem_cgroup_events_target target)
973 unsigned long val, next;
975 val = __this_cpu_read(memcg->stat->nr_page_events);
976 next = __this_cpu_read(memcg->stat->targets[target]);
977 /* from time_after() in jiffies.h */
978 if ((long)next - (long)val < 0) {
980 case MEM_CGROUP_TARGET_THRESH:
981 next = val + THRESHOLDS_EVENTS_TARGET;
983 case MEM_CGROUP_TARGET_SOFTLIMIT:
984 next = val + SOFTLIMIT_EVENTS_TARGET;
986 case MEM_CGROUP_TARGET_NUMAINFO:
987 next = val + NUMAINFO_EVENTS_TARGET;
992 __this_cpu_write(memcg->stat->targets[target], next);
999 * Check events in order.
1002 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
1005 /* threshold event is triggered in finer grain than soft limit */
1006 if (unlikely(mem_cgroup_event_ratelimit(memcg,
1007 MEM_CGROUP_TARGET_THRESH))) {
1009 bool do_numainfo __maybe_unused;
1011 do_softlimit = mem_cgroup_event_ratelimit(memcg,
1012 MEM_CGROUP_TARGET_SOFTLIMIT);
1013 #if MAX_NUMNODES > 1
1014 do_numainfo = mem_cgroup_event_ratelimit(memcg,
1015 MEM_CGROUP_TARGET_NUMAINFO);
1019 mem_cgroup_threshold(memcg);
1020 if (unlikely(do_softlimit))
1021 mem_cgroup_update_tree(memcg, page);
1022 #if MAX_NUMNODES > 1
1023 if (unlikely(do_numainfo))
1024 atomic_inc(&memcg->numainfo_events);
1030 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
1032 return mem_cgroup_from_css(
1033 cgroup_subsys_state(cont, mem_cgroup_subsys_id));
1036 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1039 * mm_update_next_owner() may clear mm->owner to NULL
1040 * if it races with swapoff, page migration, etc.
1041 * So this can be called with p == NULL.
1046 return mem_cgroup_from_css(task_subsys_state(p, mem_cgroup_subsys_id));
1049 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
1051 struct mem_cgroup *memcg = NULL;
1056 * Because we have no locks, mm->owner's may be being moved to other
1057 * cgroup. We use css_tryget() here even if this looks
1058 * pessimistic (rather than adding locks here).
1062 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1063 if (unlikely(!memcg))
1065 } while (!css_tryget(&memcg->css));
1071 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1072 * @root: hierarchy root
1073 * @prev: previously returned memcg, NULL on first invocation
1074 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1076 * Returns references to children of the hierarchy below @root, or
1077 * @root itself, or %NULL after a full round-trip.
1079 * Caller must pass the return value in @prev on subsequent
1080 * invocations for reference counting, or use mem_cgroup_iter_break()
1081 * to cancel a hierarchy walk before the round-trip is complete.
1083 * Reclaimers can specify a zone and a priority level in @reclaim to
1084 * divide up the memcgs in the hierarchy among all concurrent
1085 * reclaimers operating on the same zone and priority.
1087 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1088 struct mem_cgroup *prev,
1089 struct mem_cgroup_reclaim_cookie *reclaim)
1091 struct mem_cgroup *memcg = NULL;
1094 if (mem_cgroup_disabled())
1098 root = root_mem_cgroup;
1100 if (prev && !reclaim)
1101 id = css_id(&prev->css);
1103 if (prev && prev != root)
1104 css_put(&prev->css);
1106 if (!root->use_hierarchy && root != root_mem_cgroup) {
1113 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1114 struct cgroup_subsys_state *css;
1117 int nid = zone_to_nid(reclaim->zone);
1118 int zid = zone_idx(reclaim->zone);
1119 struct mem_cgroup_per_zone *mz;
1121 mz = mem_cgroup_zoneinfo(root, nid, zid);
1122 iter = &mz->reclaim_iter[reclaim->priority];
1123 if (prev && reclaim->generation != iter->generation)
1125 id = iter->position;
1129 css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
1131 if (css == &root->css || css_tryget(css))
1132 memcg = mem_cgroup_from_css(css);
1138 iter->position = id;
1141 else if (!prev && memcg)
1142 reclaim->generation = iter->generation;
1152 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1153 * @root: hierarchy root
1154 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1156 void mem_cgroup_iter_break(struct mem_cgroup *root,
1157 struct mem_cgroup *prev)
1160 root = root_mem_cgroup;
1161 if (prev && prev != root)
1162 css_put(&prev->css);
1166 * Iteration constructs for visiting all cgroups (under a tree). If
1167 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1168 * be used for reference counting.
1170 #define for_each_mem_cgroup_tree(iter, root) \
1171 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1173 iter = mem_cgroup_iter(root, iter, NULL))
1175 #define for_each_mem_cgroup(iter) \
1176 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1178 iter = mem_cgroup_iter(NULL, iter, NULL))
1180 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1182 struct mem_cgroup *memcg;
1185 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1186 if (unlikely(!memcg))
1191 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1194 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1202 EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1205 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1206 * @zone: zone of the wanted lruvec
1207 * @memcg: memcg of the wanted lruvec
1209 * Returns the lru list vector holding pages for the given @zone and
1210 * @mem. This can be the global zone lruvec, if the memory controller
1213 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1214 struct mem_cgroup *memcg)
1216 struct mem_cgroup_per_zone *mz;
1217 struct lruvec *lruvec;
1219 if (mem_cgroup_disabled()) {
1220 lruvec = &zone->lruvec;
1224 mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
1225 lruvec = &mz->lruvec;
1228 * Since a node can be onlined after the mem_cgroup was created,
1229 * we have to be prepared to initialize lruvec->zone here;
1230 * and if offlined then reonlined, we need to reinitialize it.
1232 if (unlikely(lruvec->zone != zone))
1233 lruvec->zone = zone;
1238 * Following LRU functions are allowed to be used without PCG_LOCK.
1239 * Operations are called by routine of global LRU independently from memcg.
1240 * What we have to take care of here is validness of pc->mem_cgroup.
1242 * Changes to pc->mem_cgroup happens when
1245 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1246 * It is added to LRU before charge.
1247 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1248 * When moving account, the page is not on LRU. It's isolated.
1252 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1254 * @zone: zone of the page
1256 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1258 struct mem_cgroup_per_zone *mz;
1259 struct mem_cgroup *memcg;
1260 struct page_cgroup *pc;
1261 struct lruvec *lruvec;
1263 if (mem_cgroup_disabled()) {
1264 lruvec = &zone->lruvec;
1268 pc = lookup_page_cgroup(page);
1269 memcg = pc->mem_cgroup;
1272 * Surreptitiously switch any uncharged offlist page to root:
1273 * an uncharged page off lru does nothing to secure
1274 * its former mem_cgroup from sudden removal.
1276 * Our caller holds lru_lock, and PageCgroupUsed is updated
1277 * under page_cgroup lock: between them, they make all uses
1278 * of pc->mem_cgroup safe.
1280 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1281 pc->mem_cgroup = memcg = root_mem_cgroup;
1283 mz = page_cgroup_zoneinfo(memcg, page);
1284 lruvec = &mz->lruvec;
1287 * Since a node can be onlined after the mem_cgroup was created,
1288 * we have to be prepared to initialize lruvec->zone here;
1289 * and if offlined then reonlined, we need to reinitialize it.
1291 if (unlikely(lruvec->zone != zone))
1292 lruvec->zone = zone;
1297 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1298 * @lruvec: mem_cgroup per zone lru vector
1299 * @lru: index of lru list the page is sitting on
1300 * @nr_pages: positive when adding or negative when removing
1302 * This function must be called when a page is added to or removed from an
1305 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1308 struct mem_cgroup_per_zone *mz;
1309 unsigned long *lru_size;
1311 if (mem_cgroup_disabled())
1314 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1315 lru_size = mz->lru_size + lru;
1316 *lru_size += nr_pages;
1317 VM_BUG_ON((long)(*lru_size) < 0);
1321 * Checks whether given mem is same or in the root_mem_cgroup's
1324 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1325 struct mem_cgroup *memcg)
1327 if (root_memcg == memcg)
1329 if (!root_memcg->use_hierarchy || !memcg)
1331 return css_is_ancestor(&memcg->css, &root_memcg->css);
1334 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1335 struct mem_cgroup *memcg)
1340 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1345 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
1348 struct mem_cgroup *curr = NULL;
1349 struct task_struct *p;
1351 p = find_lock_task_mm(task);
1353 curr = try_get_mem_cgroup_from_mm(p->mm);
1357 * All threads may have already detached their mm's, but the oom
1358 * killer still needs to detect if they have already been oom
1359 * killed to prevent needlessly killing additional tasks.
1362 curr = mem_cgroup_from_task(task);
1364 css_get(&curr->css);
1370 * We should check use_hierarchy of "memcg" not "curr". Because checking
1371 * use_hierarchy of "curr" here make this function true if hierarchy is
1372 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1373 * hierarchy(even if use_hierarchy is disabled in "memcg").
1375 ret = mem_cgroup_same_or_subtree(memcg, curr);
1376 css_put(&curr->css);
1380 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1382 unsigned long inactive_ratio;
1383 unsigned long inactive;
1384 unsigned long active;
1387 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1388 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1390 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1392 inactive_ratio = int_sqrt(10 * gb);
1396 return inactive * inactive_ratio < active;
1399 #define mem_cgroup_from_res_counter(counter, member) \
1400 container_of(counter, struct mem_cgroup, member)
1403 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1404 * @memcg: the memory cgroup
1406 * Returns the maximum amount of memory @mem can be charged with, in
1409 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1411 unsigned long long margin;
1413 margin = res_counter_margin(&memcg->res);
1414 if (do_swap_account)
1415 margin = min(margin, res_counter_margin(&memcg->memsw));
1416 return margin >> PAGE_SHIFT;
1419 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1421 struct cgroup *cgrp = memcg->css.cgroup;
1424 if (cgrp->parent == NULL)
1425 return vm_swappiness;
1427 return memcg->swappiness;
1431 * memcg->moving_account is used for checking possibility that some thread is
1432 * calling move_account(). When a thread on CPU-A starts moving pages under
1433 * a memcg, other threads should check memcg->moving_account under
1434 * rcu_read_lock(), like this:
1438 * memcg->moving_account+1 if (memcg->mocing_account)
1440 * synchronize_rcu() update something.
1445 /* for quick checking without looking up memcg */
1446 atomic_t memcg_moving __read_mostly;
1448 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1450 atomic_inc(&memcg_moving);
1451 atomic_inc(&memcg->moving_account);
1455 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1458 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1459 * We check NULL in callee rather than caller.
1462 atomic_dec(&memcg_moving);
1463 atomic_dec(&memcg->moving_account);
1468 * 2 routines for checking "mem" is under move_account() or not.
1470 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1471 * is used for avoiding races in accounting. If true,
1472 * pc->mem_cgroup may be overwritten.
1474 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1475 * under hierarchy of moving cgroups. This is for
1476 * waiting at hith-memory prressure caused by "move".
1479 static bool mem_cgroup_stolen(struct mem_cgroup *memcg)
1481 VM_BUG_ON(!rcu_read_lock_held());
1482 return atomic_read(&memcg->moving_account) > 0;
1485 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1487 struct mem_cgroup *from;
1488 struct mem_cgroup *to;
1491 * Unlike task_move routines, we access mc.to, mc.from not under
1492 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1494 spin_lock(&mc.lock);
1500 ret = mem_cgroup_same_or_subtree(memcg, from)
1501 || mem_cgroup_same_or_subtree(memcg, to);
1503 spin_unlock(&mc.lock);
1507 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1509 if (mc.moving_task && current != mc.moving_task) {
1510 if (mem_cgroup_under_move(memcg)) {
1512 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1513 /* moving charge context might have finished. */
1516 finish_wait(&mc.waitq, &wait);
1524 * Take this lock when
1525 * - a code tries to modify page's memcg while it's USED.
1526 * - a code tries to modify page state accounting in a memcg.
1527 * see mem_cgroup_stolen(), too.
1529 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1530 unsigned long *flags)
1532 spin_lock_irqsave(&memcg->move_lock, *flags);
1535 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1536 unsigned long *flags)
1538 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1541 #define K(x) ((x) << (PAGE_SHIFT-10))
1543 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1544 * @memcg: The memory cgroup that went over limit
1545 * @p: Task that is going to be killed
1547 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1550 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1552 struct cgroup *task_cgrp;
1553 struct cgroup *mem_cgrp;
1555 * Need a buffer in BSS, can't rely on allocations. The code relies
1556 * on the assumption that OOM is serialized for memory controller.
1557 * If this assumption is broken, revisit this code.
1559 static char memcg_name[PATH_MAX];
1561 struct mem_cgroup *iter;
1569 mem_cgrp = memcg->css.cgroup;
1570 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1572 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1575 * Unfortunately, we are unable to convert to a useful name
1576 * But we'll still print out the usage information
1583 pr_info("Task in %s killed", memcg_name);
1586 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1594 * Continues from above, so we don't need an KERN_ level
1596 pr_cont(" as a result of limit of %s\n", memcg_name);
1599 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1600 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1601 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1602 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1603 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1604 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1605 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1606 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1607 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1608 res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1609 res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1610 res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
1612 for_each_mem_cgroup_tree(iter, memcg) {
1613 pr_info("Memory cgroup stats");
1616 ret = cgroup_path(iter->css.cgroup, memcg_name, PATH_MAX);
1618 pr_cont(" for %s", memcg_name);
1622 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1623 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1625 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1626 K(mem_cgroup_read_stat(iter, i)));
1629 for (i = 0; i < NR_LRU_LISTS; i++)
1630 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1631 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1638 * This function returns the number of memcg under hierarchy tree. Returns
1639 * 1(self count) if no children.
1641 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1644 struct mem_cgroup *iter;
1646 for_each_mem_cgroup_tree(iter, memcg)
1652 * Return the memory (and swap, if configured) limit for a memcg.
1654 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1658 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1661 * Do not consider swap space if we cannot swap due to swappiness
1663 if (mem_cgroup_swappiness(memcg)) {
1666 limit += total_swap_pages << PAGE_SHIFT;
1667 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1670 * If memsw is finite and limits the amount of swap space
1671 * available to this memcg, return that limit.
1673 limit = min(limit, memsw);
1679 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1682 struct mem_cgroup *iter;
1683 unsigned long chosen_points = 0;
1684 unsigned long totalpages;
1685 unsigned int points = 0;
1686 struct task_struct *chosen = NULL;
1689 * If current has a pending SIGKILL, then automatically select it. The
1690 * goal is to allow it to allocate so that it may quickly exit and free
1693 if (fatal_signal_pending(current)) {
1694 set_thread_flag(TIF_MEMDIE);
1698 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1699 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1700 for_each_mem_cgroup_tree(iter, memcg) {
1701 struct cgroup *cgroup = iter->css.cgroup;
1702 struct cgroup_iter it;
1703 struct task_struct *task;
1705 cgroup_iter_start(cgroup, &it);
1706 while ((task = cgroup_iter_next(cgroup, &it))) {
1707 switch (oom_scan_process_thread(task, totalpages, NULL,
1709 case OOM_SCAN_SELECT:
1711 put_task_struct(chosen);
1713 chosen_points = ULONG_MAX;
1714 get_task_struct(chosen);
1716 case OOM_SCAN_CONTINUE:
1718 case OOM_SCAN_ABORT:
1719 cgroup_iter_end(cgroup, &it);
1720 mem_cgroup_iter_break(memcg, iter);
1722 put_task_struct(chosen);
1727 points = oom_badness(task, memcg, NULL, totalpages);
1728 if (points > chosen_points) {
1730 put_task_struct(chosen);
1732 chosen_points = points;
1733 get_task_struct(chosen);
1736 cgroup_iter_end(cgroup, &it);
1741 points = chosen_points * 1000 / totalpages;
1742 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1743 NULL, "Memory cgroup out of memory");
1746 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1748 unsigned long flags)
1750 unsigned long total = 0;
1751 bool noswap = false;
1754 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1756 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1759 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1761 drain_all_stock_async(memcg);
1762 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1764 * Allow limit shrinkers, which are triggered directly
1765 * by userspace, to catch signals and stop reclaim
1766 * after minimal progress, regardless of the margin.
1768 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1770 if (mem_cgroup_margin(memcg))
1773 * If nothing was reclaimed after two attempts, there
1774 * may be no reclaimable pages in this hierarchy.
1783 * test_mem_cgroup_node_reclaimable
1784 * @memcg: the target memcg
1785 * @nid: the node ID to be checked.
1786 * @noswap : specify true here if the user wants flle only information.
1788 * This function returns whether the specified memcg contains any
1789 * reclaimable pages on a node. Returns true if there are any reclaimable
1790 * pages in the node.
1792 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1793 int nid, bool noswap)
1795 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1797 if (noswap || !total_swap_pages)
1799 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1804 #if MAX_NUMNODES > 1
1807 * Always updating the nodemask is not very good - even if we have an empty
1808 * list or the wrong list here, we can start from some node and traverse all
1809 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1812 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1816 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1817 * pagein/pageout changes since the last update.
1819 if (!atomic_read(&memcg->numainfo_events))
1821 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1824 /* make a nodemask where this memcg uses memory from */
1825 memcg->scan_nodes = node_states[N_MEMORY];
1827 for_each_node_mask(nid, node_states[N_MEMORY]) {
1829 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1830 node_clear(nid, memcg->scan_nodes);
1833 atomic_set(&memcg->numainfo_events, 0);
1834 atomic_set(&memcg->numainfo_updating, 0);
1838 * Selecting a node where we start reclaim from. Because what we need is just
1839 * reducing usage counter, start from anywhere is O,K. Considering
1840 * memory reclaim from current node, there are pros. and cons.
1842 * Freeing memory from current node means freeing memory from a node which
1843 * we'll use or we've used. So, it may make LRU bad. And if several threads
1844 * hit limits, it will see a contention on a node. But freeing from remote
1845 * node means more costs for memory reclaim because of memory latency.
1847 * Now, we use round-robin. Better algorithm is welcomed.
1849 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1853 mem_cgroup_may_update_nodemask(memcg);
1854 node = memcg->last_scanned_node;
1856 node = next_node(node, memcg->scan_nodes);
1857 if (node == MAX_NUMNODES)
1858 node = first_node(memcg->scan_nodes);
1860 * We call this when we hit limit, not when pages are added to LRU.
1861 * No LRU may hold pages because all pages are UNEVICTABLE or
1862 * memcg is too small and all pages are not on LRU. In that case,
1863 * we use curret node.
1865 if (unlikely(node == MAX_NUMNODES))
1866 node = numa_node_id();
1868 memcg->last_scanned_node = node;
1873 * Check all nodes whether it contains reclaimable pages or not.
1874 * For quick scan, we make use of scan_nodes. This will allow us to skip
1875 * unused nodes. But scan_nodes is lazily updated and may not cotain
1876 * enough new information. We need to do double check.
1878 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1883 * quick check...making use of scan_node.
1884 * We can skip unused nodes.
1886 if (!nodes_empty(memcg->scan_nodes)) {
1887 for (nid = first_node(memcg->scan_nodes);
1889 nid = next_node(nid, memcg->scan_nodes)) {
1891 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1896 * Check rest of nodes.
1898 for_each_node_state(nid, N_MEMORY) {
1899 if (node_isset(nid, memcg->scan_nodes))
1901 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1908 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1913 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1915 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1919 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1922 unsigned long *total_scanned)
1924 struct mem_cgroup *victim = NULL;
1927 unsigned long excess;
1928 unsigned long nr_scanned;
1929 struct mem_cgroup_reclaim_cookie reclaim = {
1934 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
1937 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1942 * If we have not been able to reclaim
1943 * anything, it might because there are
1944 * no reclaimable pages under this hierarchy
1949 * We want to do more targeted reclaim.
1950 * excess >> 2 is not to excessive so as to
1951 * reclaim too much, nor too less that we keep
1952 * coming back to reclaim from this cgroup
1954 if (total >= (excess >> 2) ||
1955 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1960 if (!mem_cgroup_reclaimable(victim, false))
1962 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
1964 *total_scanned += nr_scanned;
1965 if (!res_counter_soft_limit_excess(&root_memcg->res))
1968 mem_cgroup_iter_break(root_memcg, victim);
1973 * Check OOM-Killer is already running under our hierarchy.
1974 * If someone is running, return false.
1975 * Has to be called with memcg_oom_lock
1977 static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
1979 struct mem_cgroup *iter, *failed = NULL;
1981 for_each_mem_cgroup_tree(iter, memcg) {
1982 if (iter->oom_lock) {
1984 * this subtree of our hierarchy is already locked
1985 * so we cannot give a lock.
1988 mem_cgroup_iter_break(memcg, iter);
1991 iter->oom_lock = true;
1998 * OK, we failed to lock the whole subtree so we have to clean up
1999 * what we set up to the failing subtree
2001 for_each_mem_cgroup_tree(iter, memcg) {
2002 if (iter == failed) {
2003 mem_cgroup_iter_break(memcg, iter);
2006 iter->oom_lock = false;
2012 * Has to be called with memcg_oom_lock
2014 static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
2016 struct mem_cgroup *iter;
2018 for_each_mem_cgroup_tree(iter, memcg)
2019 iter->oom_lock = false;
2023 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
2025 struct mem_cgroup *iter;
2027 for_each_mem_cgroup_tree(iter, memcg)
2028 atomic_inc(&iter->under_oom);
2031 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
2033 struct mem_cgroup *iter;
2036 * When a new child is created while the hierarchy is under oom,
2037 * mem_cgroup_oom_lock() may not be called. We have to use
2038 * atomic_add_unless() here.
2040 for_each_mem_cgroup_tree(iter, memcg)
2041 atomic_add_unless(&iter->under_oom, -1, 0);
2044 static DEFINE_SPINLOCK(memcg_oom_lock);
2045 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
2047 struct oom_wait_info {
2048 struct mem_cgroup *memcg;
2052 static int memcg_oom_wake_function(wait_queue_t *wait,
2053 unsigned mode, int sync, void *arg)
2055 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
2056 struct mem_cgroup *oom_wait_memcg;
2057 struct oom_wait_info *oom_wait_info;
2059 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
2060 oom_wait_memcg = oom_wait_info->memcg;
2063 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2064 * Then we can use css_is_ancestor without taking care of RCU.
2066 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
2067 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
2069 return autoremove_wake_function(wait, mode, sync, arg);
2072 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
2074 /* for filtering, pass "memcg" as argument. */
2075 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
2078 static void memcg_oom_recover(struct mem_cgroup *memcg)
2080 if (memcg && atomic_read(&memcg->under_oom))
2081 memcg_wakeup_oom(memcg);
2085 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
2087 static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask,
2090 struct oom_wait_info owait;
2091 bool locked, need_to_kill;
2093 owait.memcg = memcg;
2094 owait.wait.flags = 0;
2095 owait.wait.func = memcg_oom_wake_function;
2096 owait.wait.private = current;
2097 INIT_LIST_HEAD(&owait.wait.task_list);
2098 need_to_kill = true;
2099 mem_cgroup_mark_under_oom(memcg);
2101 /* At first, try to OOM lock hierarchy under memcg.*/
2102 spin_lock(&memcg_oom_lock);
2103 locked = mem_cgroup_oom_lock(memcg);
2105 * Even if signal_pending(), we can't quit charge() loop without
2106 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
2107 * under OOM is always welcomed, use TASK_KILLABLE here.
2109 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
2110 if (!locked || memcg->oom_kill_disable)
2111 need_to_kill = false;
2113 mem_cgroup_oom_notify(memcg);
2114 spin_unlock(&memcg_oom_lock);
2117 finish_wait(&memcg_oom_waitq, &owait.wait);
2118 mem_cgroup_out_of_memory(memcg, mask, order);
2121 finish_wait(&memcg_oom_waitq, &owait.wait);
2123 spin_lock(&memcg_oom_lock);
2125 mem_cgroup_oom_unlock(memcg);
2126 memcg_wakeup_oom(memcg);
2127 spin_unlock(&memcg_oom_lock);
2129 mem_cgroup_unmark_under_oom(memcg);
2131 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
2133 /* Give chance to dying process */
2134 schedule_timeout_uninterruptible(1);
2139 * Currently used to update mapped file statistics, but the routine can be
2140 * generalized to update other statistics as well.
2142 * Notes: Race condition
2144 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2145 * it tends to be costly. But considering some conditions, we doesn't need
2146 * to do so _always_.
2148 * Considering "charge", lock_page_cgroup() is not required because all
2149 * file-stat operations happen after a page is attached to radix-tree. There
2150 * are no race with "charge".
2152 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2153 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2154 * if there are race with "uncharge". Statistics itself is properly handled
2157 * Considering "move", this is an only case we see a race. To make the race
2158 * small, we check mm->moving_account and detect there are possibility of race
2159 * If there is, we take a lock.
2162 void __mem_cgroup_begin_update_page_stat(struct page *page,
2163 bool *locked, unsigned long *flags)
2165 struct mem_cgroup *memcg;
2166 struct page_cgroup *pc;
2168 pc = lookup_page_cgroup(page);
2170 memcg = pc->mem_cgroup;
2171 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2174 * If this memory cgroup is not under account moving, we don't
2175 * need to take move_lock_mem_cgroup(). Because we already hold
2176 * rcu_read_lock(), any calls to move_account will be delayed until
2177 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2179 if (!mem_cgroup_stolen(memcg))
2182 move_lock_mem_cgroup(memcg, flags);
2183 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2184 move_unlock_mem_cgroup(memcg, flags);
2190 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2192 struct page_cgroup *pc = lookup_page_cgroup(page);
2195 * It's guaranteed that pc->mem_cgroup never changes while
2196 * lock is held because a routine modifies pc->mem_cgroup
2197 * should take move_lock_mem_cgroup().
2199 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2202 void mem_cgroup_update_page_stat(struct page *page,
2203 enum mem_cgroup_page_stat_item idx, int val)
2205 struct mem_cgroup *memcg;
2206 struct page_cgroup *pc = lookup_page_cgroup(page);
2207 unsigned long uninitialized_var(flags);
2209 if (mem_cgroup_disabled())
2212 memcg = pc->mem_cgroup;
2213 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2217 case MEMCG_NR_FILE_MAPPED:
2218 idx = MEM_CGROUP_STAT_FILE_MAPPED;
2224 this_cpu_add(memcg->stat->count[idx], val);
2228 * size of first charge trial. "32" comes from vmscan.c's magic value.
2229 * TODO: maybe necessary to use big numbers in big irons.
2231 #define CHARGE_BATCH 32U
2232 struct memcg_stock_pcp {
2233 struct mem_cgroup *cached; /* this never be root cgroup */
2234 unsigned int nr_pages;
2235 struct work_struct work;
2236 unsigned long flags;
2237 #define FLUSHING_CACHED_CHARGE 0
2239 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2240 static DEFINE_MUTEX(percpu_charge_mutex);
2243 * consume_stock: Try to consume stocked charge on this cpu.
2244 * @memcg: memcg to consume from.
2245 * @nr_pages: how many pages to charge.
2247 * The charges will only happen if @memcg matches the current cpu's memcg
2248 * stock, and at least @nr_pages are available in that stock. Failure to
2249 * service an allocation will refill the stock.
2251 * returns true if successful, false otherwise.
2253 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2255 struct memcg_stock_pcp *stock;
2258 if (nr_pages > CHARGE_BATCH)
2261 stock = &get_cpu_var(memcg_stock);
2262 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2263 stock->nr_pages -= nr_pages;
2264 else /* need to call res_counter_charge */
2266 put_cpu_var(memcg_stock);
2271 * Returns stocks cached in percpu to res_counter and reset cached information.
2273 static void drain_stock(struct memcg_stock_pcp *stock)
2275 struct mem_cgroup *old = stock->cached;
2277 if (stock->nr_pages) {
2278 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2280 res_counter_uncharge(&old->res, bytes);
2281 if (do_swap_account)
2282 res_counter_uncharge(&old->memsw, bytes);
2283 stock->nr_pages = 0;
2285 stock->cached = NULL;
2289 * This must be called under preempt disabled or must be called by
2290 * a thread which is pinned to local cpu.
2292 static void drain_local_stock(struct work_struct *dummy)
2294 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2296 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2300 * Cache charges(val) which is from res_counter, to local per_cpu area.
2301 * This will be consumed by consume_stock() function, later.
2303 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2305 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2307 if (stock->cached != memcg) { /* reset if necessary */
2309 stock->cached = memcg;
2311 stock->nr_pages += nr_pages;
2312 put_cpu_var(memcg_stock);
2316 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2317 * of the hierarchy under it. sync flag says whether we should block
2318 * until the work is done.
2320 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2324 /* Notify other cpus that system-wide "drain" is running */
2327 for_each_online_cpu(cpu) {
2328 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2329 struct mem_cgroup *memcg;
2331 memcg = stock->cached;
2332 if (!memcg || !stock->nr_pages)
2334 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2336 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2338 drain_local_stock(&stock->work);
2340 schedule_work_on(cpu, &stock->work);
2348 for_each_online_cpu(cpu) {
2349 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2350 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2351 flush_work(&stock->work);
2358 * Tries to drain stocked charges in other cpus. This function is asynchronous
2359 * and just put a work per cpu for draining localy on each cpu. Caller can
2360 * expects some charges will be back to res_counter later but cannot wait for
2363 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2366 * If someone calls draining, avoid adding more kworker runs.
2368 if (!mutex_trylock(&percpu_charge_mutex))
2370 drain_all_stock(root_memcg, false);
2371 mutex_unlock(&percpu_charge_mutex);
2374 /* This is a synchronous drain interface. */
2375 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2377 /* called when force_empty is called */
2378 mutex_lock(&percpu_charge_mutex);
2379 drain_all_stock(root_memcg, true);
2380 mutex_unlock(&percpu_charge_mutex);
2384 * This function drains percpu counter value from DEAD cpu and
2385 * move it to local cpu. Note that this function can be preempted.
2387 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2391 spin_lock(&memcg->pcp_counter_lock);
2392 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2393 long x = per_cpu(memcg->stat->count[i], cpu);
2395 per_cpu(memcg->stat->count[i], cpu) = 0;
2396 memcg->nocpu_base.count[i] += x;
2398 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2399 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2401 per_cpu(memcg->stat->events[i], cpu) = 0;
2402 memcg->nocpu_base.events[i] += x;
2404 spin_unlock(&memcg->pcp_counter_lock);
2407 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2408 unsigned long action,
2411 int cpu = (unsigned long)hcpu;
2412 struct memcg_stock_pcp *stock;
2413 struct mem_cgroup *iter;
2415 if (action == CPU_ONLINE)
2418 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2421 for_each_mem_cgroup(iter)
2422 mem_cgroup_drain_pcp_counter(iter, cpu);
2424 stock = &per_cpu(memcg_stock, cpu);
2430 /* See __mem_cgroup_try_charge() for details */
2432 CHARGE_OK, /* success */
2433 CHARGE_RETRY, /* need to retry but retry is not bad */
2434 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2435 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
2436 CHARGE_OOM_DIE, /* the current is killed because of OOM */
2439 static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2440 unsigned int nr_pages, unsigned int min_pages,
2443 unsigned long csize = nr_pages * PAGE_SIZE;
2444 struct mem_cgroup *mem_over_limit;
2445 struct res_counter *fail_res;
2446 unsigned long flags = 0;
2449 ret = res_counter_charge(&memcg->res, csize, &fail_res);
2452 if (!do_swap_account)
2454 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2458 res_counter_uncharge(&memcg->res, csize);
2459 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2460 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2462 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2464 * Never reclaim on behalf of optional batching, retry with a
2465 * single page instead.
2467 if (nr_pages > min_pages)
2468 return CHARGE_RETRY;
2470 if (!(gfp_mask & __GFP_WAIT))
2471 return CHARGE_WOULDBLOCK;
2473 if (gfp_mask & __GFP_NORETRY)
2474 return CHARGE_NOMEM;
2476 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2477 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2478 return CHARGE_RETRY;
2480 * Even though the limit is exceeded at this point, reclaim
2481 * may have been able to free some pages. Retry the charge
2482 * before killing the task.
2484 * Only for regular pages, though: huge pages are rather
2485 * unlikely to succeed so close to the limit, and we fall back
2486 * to regular pages anyway in case of failure.
2488 if (nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER) && ret)
2489 return CHARGE_RETRY;
2492 * At task move, charge accounts can be doubly counted. So, it's
2493 * better to wait until the end of task_move if something is going on.
2495 if (mem_cgroup_wait_acct_move(mem_over_limit))
2496 return CHARGE_RETRY;
2498 /* If we don't need to call oom-killer at el, return immediately */
2500 return CHARGE_NOMEM;
2502 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))
2503 return CHARGE_OOM_DIE;
2505 return CHARGE_RETRY;
2509 * __mem_cgroup_try_charge() does
2510 * 1. detect memcg to be charged against from passed *mm and *ptr,
2511 * 2. update res_counter
2512 * 3. call memory reclaim if necessary.
2514 * In some special case, if the task is fatal, fatal_signal_pending() or
2515 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2516 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2517 * as possible without any hazards. 2: all pages should have a valid
2518 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2519 * pointer, that is treated as a charge to root_mem_cgroup.
2521 * So __mem_cgroup_try_charge() will return
2522 * 0 ... on success, filling *ptr with a valid memcg pointer.
2523 * -ENOMEM ... charge failure because of resource limits.
2524 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2526 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2527 * the oom-killer can be invoked.
2529 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2531 unsigned int nr_pages,
2532 struct mem_cgroup **ptr,
2535 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2536 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2537 struct mem_cgroup *memcg = NULL;
2541 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2542 * in system level. So, allow to go ahead dying process in addition to
2545 if (unlikely(test_thread_flag(TIF_MEMDIE)
2546 || fatal_signal_pending(current)))
2550 * We always charge the cgroup the mm_struct belongs to.
2551 * The mm_struct's mem_cgroup changes on task migration if the
2552 * thread group leader migrates. It's possible that mm is not
2553 * set, if so charge the root memcg (happens for pagecache usage).
2556 *ptr = root_mem_cgroup;
2558 if (*ptr) { /* css should be a valid one */
2560 if (mem_cgroup_is_root(memcg))
2562 if (consume_stock(memcg, nr_pages))
2564 css_get(&memcg->css);
2566 struct task_struct *p;
2569 p = rcu_dereference(mm->owner);
2571 * Because we don't have task_lock(), "p" can exit.
2572 * In that case, "memcg" can point to root or p can be NULL with
2573 * race with swapoff. Then, we have small risk of mis-accouning.
2574 * But such kind of mis-account by race always happens because
2575 * we don't have cgroup_mutex(). It's overkill and we allo that
2577 * (*) swapoff at el will charge against mm-struct not against
2578 * task-struct. So, mm->owner can be NULL.
2580 memcg = mem_cgroup_from_task(p);
2582 memcg = root_mem_cgroup;
2583 if (mem_cgroup_is_root(memcg)) {
2587 if (consume_stock(memcg, nr_pages)) {
2589 * It seems dagerous to access memcg without css_get().
2590 * But considering how consume_stok works, it's not
2591 * necessary. If consume_stock success, some charges
2592 * from this memcg are cached on this cpu. So, we
2593 * don't need to call css_get()/css_tryget() before
2594 * calling consume_stock().
2599 /* after here, we may be blocked. we need to get refcnt */
2600 if (!css_tryget(&memcg->css)) {
2610 /* If killed, bypass charge */
2611 if (fatal_signal_pending(current)) {
2612 css_put(&memcg->css);
2617 if (oom && !nr_oom_retries) {
2619 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2622 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, nr_pages,
2627 case CHARGE_RETRY: /* not in OOM situation but retry */
2629 css_put(&memcg->css);
2632 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2633 css_put(&memcg->css);
2635 case CHARGE_NOMEM: /* OOM routine works */
2637 css_put(&memcg->css);
2640 /* If oom, we never return -ENOMEM */
2643 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2644 css_put(&memcg->css);
2647 } while (ret != CHARGE_OK);
2649 if (batch > nr_pages)
2650 refill_stock(memcg, batch - nr_pages);
2651 css_put(&memcg->css);
2659 *ptr = root_mem_cgroup;
2664 * Somemtimes we have to undo a charge we got by try_charge().
2665 * This function is for that and do uncharge, put css's refcnt.
2666 * gotten by try_charge().
2668 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2669 unsigned int nr_pages)
2671 if (!mem_cgroup_is_root(memcg)) {
2672 unsigned long bytes = nr_pages * PAGE_SIZE;
2674 res_counter_uncharge(&memcg->res, bytes);
2675 if (do_swap_account)
2676 res_counter_uncharge(&memcg->memsw, bytes);
2681 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2682 * This is useful when moving usage to parent cgroup.
2684 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2685 unsigned int nr_pages)
2687 unsigned long bytes = nr_pages * PAGE_SIZE;
2689 if (mem_cgroup_is_root(memcg))
2692 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2693 if (do_swap_account)
2694 res_counter_uncharge_until(&memcg->memsw,
2695 memcg->memsw.parent, bytes);
2699 * A helper function to get mem_cgroup from ID. must be called under
2700 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2701 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2702 * called against removed memcg.)
2704 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2706 struct cgroup_subsys_state *css;
2708 /* ID 0 is unused ID */
2711 css = css_lookup(&mem_cgroup_subsys, id);
2714 return mem_cgroup_from_css(css);
2717 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2719 struct mem_cgroup *memcg = NULL;
2720 struct page_cgroup *pc;
2724 VM_BUG_ON(!PageLocked(page));
2726 pc = lookup_page_cgroup(page);
2727 lock_page_cgroup(pc);
2728 if (PageCgroupUsed(pc)) {
2729 memcg = pc->mem_cgroup;
2730 if (memcg && !css_tryget(&memcg->css))
2732 } else if (PageSwapCache(page)) {
2733 ent.val = page_private(page);
2734 id = lookup_swap_cgroup_id(ent);
2736 memcg = mem_cgroup_lookup(id);
2737 if (memcg && !css_tryget(&memcg->css))
2741 unlock_page_cgroup(pc);
2745 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2747 unsigned int nr_pages,
2748 enum charge_type ctype,
2751 struct page_cgroup *pc = lookup_page_cgroup(page);
2752 struct zone *uninitialized_var(zone);
2753 struct lruvec *lruvec;
2754 bool was_on_lru = false;
2757 lock_page_cgroup(pc);
2758 VM_BUG_ON(PageCgroupUsed(pc));
2760 * we don't need page_cgroup_lock about tail pages, becase they are not
2761 * accessed by any other context at this point.
2765 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2766 * may already be on some other mem_cgroup's LRU. Take care of it.
2769 zone = page_zone(page);
2770 spin_lock_irq(&zone->lru_lock);
2771 if (PageLRU(page)) {
2772 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2774 del_page_from_lru_list(page, lruvec, page_lru(page));
2779 pc->mem_cgroup = memcg;
2781 * We access a page_cgroup asynchronously without lock_page_cgroup().
2782 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2783 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2784 * before USED bit, we need memory barrier here.
2785 * See mem_cgroup_add_lru_list(), etc.
2788 SetPageCgroupUsed(pc);
2792 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2793 VM_BUG_ON(PageLRU(page));
2795 add_page_to_lru_list(page, lruvec, page_lru(page));
2797 spin_unlock_irq(&zone->lru_lock);
2800 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2805 mem_cgroup_charge_statistics(memcg, anon, nr_pages);
2806 unlock_page_cgroup(pc);
2809 * "charge_statistics" updated event counter. Then, check it.
2810 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2811 * if they exceeds softlimit.
2813 memcg_check_events(memcg, page);
2816 static DEFINE_MUTEX(set_limit_mutex);
2818 #ifdef CONFIG_MEMCG_KMEM
2819 static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2821 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2822 (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK);
2826 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2827 * in the memcg_cache_params struct.
2829 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2831 struct kmem_cache *cachep;
2833 VM_BUG_ON(p->is_root_cache);
2834 cachep = p->root_cache;
2835 return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)];
2838 #ifdef CONFIG_SLABINFO
2839 static int mem_cgroup_slabinfo_read(struct cgroup *cont, struct cftype *cft,
2842 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
2843 struct memcg_cache_params *params;
2845 if (!memcg_can_account_kmem(memcg))
2848 print_slabinfo_header(m);
2850 mutex_lock(&memcg->slab_caches_mutex);
2851 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2852 cache_show(memcg_params_to_cache(params), m);
2853 mutex_unlock(&memcg->slab_caches_mutex);
2859 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2861 struct res_counter *fail_res;
2862 struct mem_cgroup *_memcg;
2866 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2871 * Conditions under which we can wait for the oom_killer. Those are
2872 * the same conditions tested by the core page allocator
2874 may_oom = (gfp & __GFP_FS) && !(gfp & __GFP_NORETRY);
2877 ret = __mem_cgroup_try_charge(NULL, gfp, size >> PAGE_SHIFT,
2880 if (ret == -EINTR) {
2882 * __mem_cgroup_try_charge() chosed to bypass to root due to
2883 * OOM kill or fatal signal. Since our only options are to
2884 * either fail the allocation or charge it to this cgroup, do
2885 * it as a temporary condition. But we can't fail. From a
2886 * kmem/slab perspective, the cache has already been selected,
2887 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2890 * This condition will only trigger if the task entered
2891 * memcg_charge_kmem in a sane state, but was OOM-killed during
2892 * __mem_cgroup_try_charge() above. Tasks that were already
2893 * dying when the allocation triggers should have been already
2894 * directed to the root cgroup in memcontrol.h
2896 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2897 if (do_swap_account)
2898 res_counter_charge_nofail(&memcg->memsw, size,
2902 res_counter_uncharge(&memcg->kmem, size);
2907 static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2909 res_counter_uncharge(&memcg->res, size);
2910 if (do_swap_account)
2911 res_counter_uncharge(&memcg->memsw, size);
2914 if (res_counter_uncharge(&memcg->kmem, size))
2917 if (memcg_kmem_test_and_clear_dead(memcg))
2918 mem_cgroup_put(memcg);
2921 void memcg_cache_list_add(struct mem_cgroup *memcg, struct kmem_cache *cachep)
2926 mutex_lock(&memcg->slab_caches_mutex);
2927 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
2928 mutex_unlock(&memcg->slab_caches_mutex);
2932 * helper for acessing a memcg's index. It will be used as an index in the
2933 * child cache array in kmem_cache, and also to derive its name. This function
2934 * will return -1 when this is not a kmem-limited memcg.
2936 int memcg_cache_id(struct mem_cgroup *memcg)
2938 return memcg ? memcg->kmemcg_id : -1;
2942 * This ends up being protected by the set_limit mutex, during normal
2943 * operation, because that is its main call site.
2945 * But when we create a new cache, we can call this as well if its parent
2946 * is kmem-limited. That will have to hold set_limit_mutex as well.
2948 int memcg_update_cache_sizes(struct mem_cgroup *memcg)
2952 num = ida_simple_get(&kmem_limited_groups,
2953 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2957 * After this point, kmem_accounted (that we test atomically in
2958 * the beginning of this conditional), is no longer 0. This
2959 * guarantees only one process will set the following boolean
2960 * to true. We don't need test_and_set because we're protected
2961 * by the set_limit_mutex anyway.
2963 memcg_kmem_set_activated(memcg);
2965 ret = memcg_update_all_caches(num+1);
2967 ida_simple_remove(&kmem_limited_groups, num);
2968 memcg_kmem_clear_activated(memcg);
2972 memcg->kmemcg_id = num;
2973 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
2974 mutex_init(&memcg->slab_caches_mutex);
2978 static size_t memcg_caches_array_size(int num_groups)
2981 if (num_groups <= 0)
2984 size = 2 * num_groups;
2985 if (size < MEMCG_CACHES_MIN_SIZE)
2986 size = MEMCG_CACHES_MIN_SIZE;
2987 else if (size > MEMCG_CACHES_MAX_SIZE)
2988 size = MEMCG_CACHES_MAX_SIZE;
2994 * We should update the current array size iff all caches updates succeed. This
2995 * can only be done from the slab side. The slab mutex needs to be held when
2998 void memcg_update_array_size(int num)
3000 if (num > memcg_limited_groups_array_size)
3001 memcg_limited_groups_array_size = memcg_caches_array_size(num);
3004 int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
3006 struct memcg_cache_params *cur_params = s->memcg_params;
3008 VM_BUG_ON(s->memcg_params && !s->memcg_params->is_root_cache);
3010 if (num_groups > memcg_limited_groups_array_size) {
3012 ssize_t size = memcg_caches_array_size(num_groups);
3014 size *= sizeof(void *);
3015 size += sizeof(struct memcg_cache_params);
3017 s->memcg_params = kzalloc(size, GFP_KERNEL);
3018 if (!s->memcg_params) {
3019 s->memcg_params = cur_params;
3023 s->memcg_params->is_root_cache = true;
3026 * There is the chance it will be bigger than
3027 * memcg_limited_groups_array_size, if we failed an allocation
3028 * in a cache, in which case all caches updated before it, will
3029 * have a bigger array.
3031 * But if that is the case, the data after
3032 * memcg_limited_groups_array_size is certainly unused
3034 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3035 if (!cur_params->memcg_caches[i])
3037 s->memcg_params->memcg_caches[i] =
3038 cur_params->memcg_caches[i];
3042 * Ideally, we would wait until all caches succeed, and only
3043 * then free the old one. But this is not worth the extra
3044 * pointer per-cache we'd have to have for this.
3046 * It is not a big deal if some caches are left with a size
3047 * bigger than the others. And all updates will reset this
3055 int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
3056 struct kmem_cache *root_cache)
3058 size_t size = sizeof(struct memcg_cache_params);
3060 if (!memcg_kmem_enabled())
3064 size += memcg_limited_groups_array_size * sizeof(void *);
3066 s->memcg_params = kzalloc(size, GFP_KERNEL);
3067 if (!s->memcg_params)
3071 s->memcg_params->memcg = memcg;
3072 s->memcg_params->root_cache = root_cache;
3074 s->memcg_params->is_root_cache = true;
3079 void memcg_release_cache(struct kmem_cache *s)
3081 struct kmem_cache *root;
3082 struct mem_cgroup *memcg;
3086 * This happens, for instance, when a root cache goes away before we
3089 if (!s->memcg_params)
3092 if (s->memcg_params->is_root_cache)
3095 memcg = s->memcg_params->memcg;
3096 id = memcg_cache_id(memcg);
3098 root = s->memcg_params->root_cache;
3099 root->memcg_params->memcg_caches[id] = NULL;
3100 mem_cgroup_put(memcg);
3102 mutex_lock(&memcg->slab_caches_mutex);
3103 list_del(&s->memcg_params->list);
3104 mutex_unlock(&memcg->slab_caches_mutex);
3107 kfree(s->memcg_params);
3111 * During the creation a new cache, we need to disable our accounting mechanism
3112 * altogether. This is true even if we are not creating, but rather just
3113 * enqueing new caches to be created.
3115 * This is because that process will trigger allocations; some visible, like
3116 * explicit kmallocs to auxiliary data structures, name strings and internal
3117 * cache structures; some well concealed, like INIT_WORK() that can allocate
3118 * objects during debug.
3120 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3121 * to it. This may not be a bounded recursion: since the first cache creation
3122 * failed to complete (waiting on the allocation), we'll just try to create the
3123 * cache again, failing at the same point.
3125 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3126 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3127 * inside the following two functions.
3129 static inline void memcg_stop_kmem_account(void)
3131 VM_BUG_ON(!current->mm);
3132 current->memcg_kmem_skip_account++;
3135 static inline void memcg_resume_kmem_account(void)
3137 VM_BUG_ON(!current->mm);
3138 current->memcg_kmem_skip_account--;
3141 static void kmem_cache_destroy_work_func(struct work_struct *w)
3143 struct kmem_cache *cachep;
3144 struct memcg_cache_params *p;
3146 p = container_of(w, struct memcg_cache_params, destroy);
3148 cachep = memcg_params_to_cache(p);
3151 * If we get down to 0 after shrink, we could delete right away.
3152 * However, memcg_release_pages() already puts us back in the workqueue
3153 * in that case. If we proceed deleting, we'll get a dangling
3154 * reference, and removing the object from the workqueue in that case
3155 * is unnecessary complication. We are not a fast path.
3157 * Note that this case is fundamentally different from racing with
3158 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3159 * kmem_cache_shrink, not only we would be reinserting a dead cache
3160 * into the queue, but doing so from inside the worker racing to
3163 * So if we aren't down to zero, we'll just schedule a worker and try
3166 if (atomic_read(&cachep->memcg_params->nr_pages) != 0) {
3167 kmem_cache_shrink(cachep);
3168 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
3171 kmem_cache_destroy(cachep);
3174 void mem_cgroup_destroy_cache(struct kmem_cache *cachep)
3176 if (!cachep->memcg_params->dead)
3180 * There are many ways in which we can get here.
3182 * We can get to a memory-pressure situation while the delayed work is
3183 * still pending to run. The vmscan shrinkers can then release all
3184 * cache memory and get us to destruction. If this is the case, we'll
3185 * be executed twice, which is a bug (the second time will execute over
3186 * bogus data). In this case, cancelling the work should be fine.
3188 * But we can also get here from the worker itself, if
3189 * kmem_cache_shrink is enough to shake all the remaining objects and
3190 * get the page count to 0. In this case, we'll deadlock if we try to
3191 * cancel the work (the worker runs with an internal lock held, which
3192 * is the same lock we would hold for cancel_work_sync().)
3194 * Since we can't possibly know who got us here, just refrain from
3195 * running if there is already work pending
3197 if (work_pending(&cachep->memcg_params->destroy))
3200 * We have to defer the actual destroying to a workqueue, because
3201 * we might currently be in a context that cannot sleep.
3203 schedule_work(&cachep->memcg_params->destroy);
3206 static char *memcg_cache_name(struct mem_cgroup *memcg, struct kmem_cache *s)
3209 struct dentry *dentry;
3212 dentry = rcu_dereference(memcg->css.cgroup->dentry);
3215 BUG_ON(dentry == NULL);
3217 name = kasprintf(GFP_KERNEL, "%s(%d:%s)", s->name,
3218 memcg_cache_id(memcg), dentry->d_name.name);
3223 static struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
3224 struct kmem_cache *s)
3227 struct kmem_cache *new;
3229 name = memcg_cache_name(memcg, s);
3233 new = kmem_cache_create_memcg(memcg, name, s->object_size, s->align,
3234 (s->flags & ~SLAB_PANIC), s->ctor, s);
3237 new->allocflags |= __GFP_KMEMCG;
3244 * This lock protects updaters, not readers. We want readers to be as fast as
3245 * they can, and they will either see NULL or a valid cache value. Our model
3246 * allow them to see NULL, in which case the root memcg will be selected.
3248 * We need this lock because multiple allocations to the same cache from a non
3249 * will span more than one worker. Only one of them can create the cache.
3251 static DEFINE_MUTEX(memcg_cache_mutex);
3252 static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
3253 struct kmem_cache *cachep)
3255 struct kmem_cache *new_cachep;
3258 BUG_ON(!memcg_can_account_kmem(memcg));
3260 idx = memcg_cache_id(memcg);
3262 mutex_lock(&memcg_cache_mutex);
3263 new_cachep = cachep->memcg_params->memcg_caches[idx];
3267 new_cachep = kmem_cache_dup(memcg, cachep);
3268 if (new_cachep == NULL) {
3269 new_cachep = cachep;
3273 mem_cgroup_get(memcg);
3274 atomic_set(&new_cachep->memcg_params->nr_pages , 0);
3276 cachep->memcg_params->memcg_caches[idx] = new_cachep;
3278 * the readers won't lock, make sure everybody sees the updated value,
3279 * so they won't put stuff in the queue again for no reason
3283 mutex_unlock(&memcg_cache_mutex);
3287 void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
3289 struct kmem_cache *c;
3292 if (!s->memcg_params)
3294 if (!s->memcg_params->is_root_cache)
3298 * If the cache is being destroyed, we trust that there is no one else
3299 * requesting objects from it. Even if there are, the sanity checks in
3300 * kmem_cache_destroy should caught this ill-case.
3302 * Still, we don't want anyone else freeing memcg_caches under our
3303 * noses, which can happen if a new memcg comes to life. As usual,
3304 * we'll take the set_limit_mutex to protect ourselves against this.
3306 mutex_lock(&set_limit_mutex);
3307 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3308 c = s->memcg_params->memcg_caches[i];
3313 * We will now manually delete the caches, so to avoid races
3314 * we need to cancel all pending destruction workers and
3315 * proceed with destruction ourselves.
3317 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3318 * and that could spawn the workers again: it is likely that
3319 * the cache still have active pages until this very moment.
3320 * This would lead us back to mem_cgroup_destroy_cache.
3322 * But that will not execute at all if the "dead" flag is not
3323 * set, so flip it down to guarantee we are in control.
3325 c->memcg_params->dead = false;
3326 cancel_work_sync(&c->memcg_params->destroy);
3327 kmem_cache_destroy(c);
3329 mutex_unlock(&set_limit_mutex);
3332 struct create_work {
3333 struct mem_cgroup *memcg;
3334 struct kmem_cache *cachep;
3335 struct work_struct work;
3338 static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3340 struct kmem_cache *cachep;
3341 struct memcg_cache_params *params;
3343 if (!memcg_kmem_is_active(memcg))
3346 mutex_lock(&memcg->slab_caches_mutex);
3347 list_for_each_entry(params, &memcg->memcg_slab_caches, list) {
3348 cachep = memcg_params_to_cache(params);
3349 cachep->memcg_params->dead = true;
3350 INIT_WORK(&cachep->memcg_params->destroy,
3351 kmem_cache_destroy_work_func);
3352 schedule_work(&cachep->memcg_params->destroy);
3354 mutex_unlock(&memcg->slab_caches_mutex);
3357 static void memcg_create_cache_work_func(struct work_struct *w)
3359 struct create_work *cw;
3361 cw = container_of(w, struct create_work, work);
3362 memcg_create_kmem_cache(cw->memcg, cw->cachep);
3363 /* Drop the reference gotten when we enqueued. */
3364 css_put(&cw->memcg->css);
3369 * Enqueue the creation of a per-memcg kmem_cache.
3370 * Called with rcu_read_lock.
3372 static void __memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3373 struct kmem_cache *cachep)
3375 struct create_work *cw;
3377 cw = kmalloc(sizeof(struct create_work), GFP_NOWAIT);
3381 /* The corresponding put will be done in the workqueue. */
3382 if (!css_tryget(&memcg->css)) {
3388 cw->cachep = cachep;
3390 INIT_WORK(&cw->work, memcg_create_cache_work_func);
3391 schedule_work(&cw->work);
3394 static void memcg_create_cache_enqueue(struct mem_cgroup *memcg,
3395 struct kmem_cache *cachep)
3398 * We need to stop accounting when we kmalloc, because if the
3399 * corresponding kmalloc cache is not yet created, the first allocation
3400 * in __memcg_create_cache_enqueue will recurse.
3402 * However, it is better to enclose the whole function. Depending on
3403 * the debugging options enabled, INIT_WORK(), for instance, can
3404 * trigger an allocation. This too, will make us recurse. Because at
3405 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3406 * the safest choice is to do it like this, wrapping the whole function.
3408 memcg_stop_kmem_account();
3409 __memcg_create_cache_enqueue(memcg, cachep);
3410 memcg_resume_kmem_account();
3413 * Return the kmem_cache we're supposed to use for a slab allocation.
3414 * We try to use the current memcg's version of the cache.
3416 * If the cache does not exist yet, if we are the first user of it,
3417 * we either create it immediately, if possible, or create it asynchronously
3419 * In the latter case, we will let the current allocation go through with
3420 * the original cache.
3422 * Can't be called in interrupt context or from kernel threads.
3423 * This function needs to be called with rcu_read_lock() held.
3425 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3428 struct mem_cgroup *memcg;
3431 VM_BUG_ON(!cachep->memcg_params);
3432 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3434 if (!current->mm || current->memcg_kmem_skip_account)
3438 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3441 if (!memcg_can_account_kmem(memcg))
3444 idx = memcg_cache_id(memcg);
3447 * barrier to mare sure we're always seeing the up to date value. The
3448 * code updating memcg_caches will issue a write barrier to match this.
3450 read_barrier_depends();
3451 if (unlikely(cachep->memcg_params->memcg_caches[idx] == NULL)) {
3453 * If we are in a safe context (can wait, and not in interrupt
3454 * context), we could be be predictable and return right away.
3455 * This would guarantee that the allocation being performed
3456 * already belongs in the new cache.
3458 * However, there are some clashes that can arrive from locking.
3459 * For instance, because we acquire the slab_mutex while doing
3460 * kmem_cache_dup, this means no further allocation could happen
3461 * with the slab_mutex held.
3463 * Also, because cache creation issue get_online_cpus(), this
3464 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3465 * that ends up reversed during cpu hotplug. (cpuset allocates
3466 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3467 * better to defer everything.
3469 memcg_create_cache_enqueue(memcg, cachep);
3473 return cachep->memcg_params->memcg_caches[idx];
3475 EXPORT_SYMBOL(__memcg_kmem_get_cache);
3478 * We need to verify if the allocation against current->mm->owner's memcg is
3479 * possible for the given order. But the page is not allocated yet, so we'll
3480 * need a further commit step to do the final arrangements.
3482 * It is possible for the task to switch cgroups in this mean time, so at
3483 * commit time, we can't rely on task conversion any longer. We'll then use
3484 * the handle argument to return to the caller which cgroup we should commit
3485 * against. We could also return the memcg directly and avoid the pointer
3486 * passing, but a boolean return value gives better semantics considering
3487 * the compiled-out case as well.
3489 * Returning true means the allocation is possible.
3492 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3494 struct mem_cgroup *memcg;
3498 memcg = try_get_mem_cgroup_from_mm(current->mm);
3501 * very rare case described in mem_cgroup_from_task. Unfortunately there
3502 * isn't much we can do without complicating this too much, and it would
3503 * be gfp-dependent anyway. Just let it go
3505 if (unlikely(!memcg))
3508 if (!memcg_can_account_kmem(memcg)) {
3509 css_put(&memcg->css);
3513 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3517 css_put(&memcg->css);
3521 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3524 struct page_cgroup *pc;
3526 VM_BUG_ON(mem_cgroup_is_root(memcg));
3528 /* The page allocation failed. Revert */
3530 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3534 pc = lookup_page_cgroup(page);
3535 lock_page_cgroup(pc);
3536 pc->mem_cgroup = memcg;
3537 SetPageCgroupUsed(pc);
3538 unlock_page_cgroup(pc);
3541 void __memcg_kmem_uncharge_pages(struct page *page, int order)
3543 struct mem_cgroup *memcg = NULL;
3544 struct page_cgroup *pc;
3547 pc = lookup_page_cgroup(page);
3549 * Fast unlocked return. Theoretically might have changed, have to
3550 * check again after locking.
3552 if (!PageCgroupUsed(pc))
3555 lock_page_cgroup(pc);
3556 if (PageCgroupUsed(pc)) {
3557 memcg = pc->mem_cgroup;
3558 ClearPageCgroupUsed(pc);
3560 unlock_page_cgroup(pc);
3563 * We trust that only if there is a memcg associated with the page, it
3564 * is a valid allocation
3569 VM_BUG_ON(mem_cgroup_is_root(memcg));
3570 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3573 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg)
3576 #endif /* CONFIG_MEMCG_KMEM */
3578 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3580 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3582 * Because tail pages are not marked as "used", set it. We're under
3583 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3584 * charge/uncharge will be never happen and move_account() is done under
3585 * compound_lock(), so we don't have to take care of races.
3587 void mem_cgroup_split_huge_fixup(struct page *head)
3589 struct page_cgroup *head_pc = lookup_page_cgroup(head);
3590 struct page_cgroup *pc;
3593 if (mem_cgroup_disabled())
3595 for (i = 1; i < HPAGE_PMD_NR; i++) {
3597 pc->mem_cgroup = head_pc->mem_cgroup;
3598 smp_wmb();/* see __commit_charge() */
3599 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3602 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3605 * mem_cgroup_move_account - move account of the page
3607 * @nr_pages: number of regular pages (>1 for huge pages)
3608 * @pc: page_cgroup of the page.
3609 * @from: mem_cgroup which the page is moved from.
3610 * @to: mem_cgroup which the page is moved to. @from != @to.
3612 * The caller must confirm following.
3613 * - page is not on LRU (isolate_page() is useful.)
3614 * - compound_lock is held when nr_pages > 1
3616 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3619 static int mem_cgroup_move_account(struct page *page,
3620 unsigned int nr_pages,
3621 struct page_cgroup *pc,
3622 struct mem_cgroup *from,
3623 struct mem_cgroup *to)
3625 unsigned long flags;
3627 bool anon = PageAnon(page);
3629 VM_BUG_ON(from == to);
3630 VM_BUG_ON(PageLRU(page));
3632 * The page is isolated from LRU. So, collapse function
3633 * will not handle this page. But page splitting can happen.
3634 * Do this check under compound_page_lock(). The caller should
3638 if (nr_pages > 1 && !PageTransHuge(page))
3641 lock_page_cgroup(pc);
3644 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3647 move_lock_mem_cgroup(from, &flags);
3649 if (!anon && page_mapped(page)) {
3650 /* Update mapped_file data for mem_cgroup */
3652 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3653 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
3656 mem_cgroup_charge_statistics(from, anon, -nr_pages);
3658 /* caller should have done css_get */
3659 pc->mem_cgroup = to;
3660 mem_cgroup_charge_statistics(to, anon, nr_pages);
3661 move_unlock_mem_cgroup(from, &flags);
3664 unlock_page_cgroup(pc);
3668 memcg_check_events(to, page);
3669 memcg_check_events(from, page);
3675 * mem_cgroup_move_parent - moves page to the parent group
3676 * @page: the page to move
3677 * @pc: page_cgroup of the page
3678 * @child: page's cgroup
3680 * move charges to its parent or the root cgroup if the group has no
3681 * parent (aka use_hierarchy==0).
3682 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3683 * mem_cgroup_move_account fails) the failure is always temporary and
3684 * it signals a race with a page removal/uncharge or migration. In the
3685 * first case the page is on the way out and it will vanish from the LRU
3686 * on the next attempt and the call should be retried later.
3687 * Isolation from the LRU fails only if page has been isolated from
3688 * the LRU since we looked at it and that usually means either global
3689 * reclaim or migration going on. The page will either get back to the
3691 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3692 * (!PageCgroupUsed) or moved to a different group. The page will
3693 * disappear in the next attempt.
3695 static int mem_cgroup_move_parent(struct page *page,
3696 struct page_cgroup *pc,
3697 struct mem_cgroup *child)
3699 struct mem_cgroup *parent;
3700 unsigned int nr_pages;
3701 unsigned long uninitialized_var(flags);
3704 VM_BUG_ON(mem_cgroup_is_root(child));
3707 if (!get_page_unless_zero(page))
3709 if (isolate_lru_page(page))
3712 nr_pages = hpage_nr_pages(page);
3714 parent = parent_mem_cgroup(child);
3716 * If no parent, move charges to root cgroup.
3719 parent = root_mem_cgroup;
3722 VM_BUG_ON(!PageTransHuge(page));
3723 flags = compound_lock_irqsave(page);
3726 ret = mem_cgroup_move_account(page, nr_pages,
3729 __mem_cgroup_cancel_local_charge(child, nr_pages);
3732 compound_unlock_irqrestore(page, flags);
3733 putback_lru_page(page);
3741 * Charge the memory controller for page usage.
3743 * 0 if the charge was successful
3744 * < 0 if the cgroup is over its limit
3746 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
3747 gfp_t gfp_mask, enum charge_type ctype)
3749 struct mem_cgroup *memcg = NULL;
3750 unsigned int nr_pages = 1;
3754 if (PageTransHuge(page)) {
3755 nr_pages <<= compound_order(page);
3756 VM_BUG_ON(!PageTransHuge(page));
3758 * Never OOM-kill a process for a huge page. The
3759 * fault handler will fall back to regular pages.
3764 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
3767 __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
3771 int mem_cgroup_newpage_charge(struct page *page,
3772 struct mm_struct *mm, gfp_t gfp_mask)
3774 if (mem_cgroup_disabled())
3776 VM_BUG_ON(page_mapped(page));
3777 VM_BUG_ON(page->mapping && !PageAnon(page));
3779 return mem_cgroup_charge_common(page, mm, gfp_mask,
3780 MEM_CGROUP_CHARGE_TYPE_ANON);
3784 * While swap-in, try_charge -> commit or cancel, the page is locked.
3785 * And when try_charge() successfully returns, one refcnt to memcg without
3786 * struct page_cgroup is acquired. This refcnt will be consumed by
3787 * "commit()" or removed by "cancel()"
3789 static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3792 struct mem_cgroup **memcgp)
3794 struct mem_cgroup *memcg;
3795 struct page_cgroup *pc;
3798 pc = lookup_page_cgroup(page);
3800 * Every swap fault against a single page tries to charge the
3801 * page, bail as early as possible. shmem_unuse() encounters
3802 * already charged pages, too. The USED bit is protected by
3803 * the page lock, which serializes swap cache removal, which
3804 * in turn serializes uncharging.
3806 if (PageCgroupUsed(pc))
3808 if (!do_swap_account)
3810 memcg = try_get_mem_cgroup_from_page(page);
3814 ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
3815 css_put(&memcg->css);
3820 ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
3826 int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3827 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3830 if (mem_cgroup_disabled())
3833 * A racing thread's fault, or swapoff, may have already
3834 * updated the pte, and even removed page from swap cache: in
3835 * those cases unuse_pte()'s pte_same() test will fail; but
3836 * there's also a KSM case which does need to charge the page.
3838 if (!PageSwapCache(page)) {
3841 ret = __mem_cgroup_try_charge(mm, gfp_mask, 1, memcgp, true);
3846 return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3849 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3851 if (mem_cgroup_disabled())
3855 __mem_cgroup_cancel_charge(memcg, 1);
3859 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
3860 enum charge_type ctype)
3862 if (mem_cgroup_disabled())
3867 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
3869 * Now swap is on-memory. This means this page may be
3870 * counted both as mem and swap....double count.
3871 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3872 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3873 * may call delete_from_swap_cache() before reach here.
3875 if (do_swap_account && PageSwapCache(page)) {
3876 swp_entry_t ent = {.val = page_private(page)};
3877 mem_cgroup_uncharge_swap(ent);
3881 void mem_cgroup_commit_charge_swapin(struct page *page,
3882 struct mem_cgroup *memcg)
3884 __mem_cgroup_commit_charge_swapin(page, memcg,
3885 MEM_CGROUP_CHARGE_TYPE_ANON);
3888 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
3891 struct mem_cgroup *memcg = NULL;
3892 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3895 if (mem_cgroup_disabled())
3897 if (PageCompound(page))
3900 if (!PageSwapCache(page))
3901 ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
3902 else { /* page is swapcache/shmem */
3903 ret = __mem_cgroup_try_charge_swapin(mm, page,
3906 __mem_cgroup_commit_charge_swapin(page, memcg, type);
3911 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
3912 unsigned int nr_pages,
3913 const enum charge_type ctype)
3915 struct memcg_batch_info *batch = NULL;
3916 bool uncharge_memsw = true;
3918 /* If swapout, usage of swap doesn't decrease */
3919 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3920 uncharge_memsw = false;
3922 batch = ¤t->memcg_batch;
3924 * In usual, we do css_get() when we remember memcg pointer.
3925 * But in this case, we keep res->usage until end of a series of
3926 * uncharges. Then, it's ok to ignore memcg's refcnt.
3929 batch->memcg = memcg;
3931 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3932 * In those cases, all pages freed continuously can be expected to be in
3933 * the same cgroup and we have chance to coalesce uncharges.
3934 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3935 * because we want to do uncharge as soon as possible.
3938 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
3939 goto direct_uncharge;
3942 goto direct_uncharge;
3945 * In typical case, batch->memcg == mem. This means we can
3946 * merge a series of uncharges to an uncharge of res_counter.
3947 * If not, we uncharge res_counter ony by one.
3949 if (batch->memcg != memcg)
3950 goto direct_uncharge;
3951 /* remember freed charge and uncharge it later */
3954 batch->memsw_nr_pages++;
3957 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
3959 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
3960 if (unlikely(batch->memcg != memcg))
3961 memcg_oom_recover(memcg);
3965 * uncharge if !page_mapped(page)
3967 static struct mem_cgroup *
3968 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
3971 struct mem_cgroup *memcg = NULL;
3972 unsigned int nr_pages = 1;
3973 struct page_cgroup *pc;
3976 if (mem_cgroup_disabled())
3979 VM_BUG_ON(PageSwapCache(page));
3981 if (PageTransHuge(page)) {
3982 nr_pages <<= compound_order(page);
3983 VM_BUG_ON(!PageTransHuge(page));
3986 * Check if our page_cgroup is valid
3988 pc = lookup_page_cgroup(page);
3989 if (unlikely(!PageCgroupUsed(pc)))
3992 lock_page_cgroup(pc);
3994 memcg = pc->mem_cgroup;
3996 if (!PageCgroupUsed(pc))
3999 anon = PageAnon(page);
4002 case MEM_CGROUP_CHARGE_TYPE_ANON:
4004 * Generally PageAnon tells if it's the anon statistics to be
4005 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4006 * used before page reached the stage of being marked PageAnon.
4010 case MEM_CGROUP_CHARGE_TYPE_DROP:
4011 /* See mem_cgroup_prepare_migration() */
4012 if (page_mapped(page))
4015 * Pages under migration may not be uncharged. But
4016 * end_migration() /must/ be the one uncharging the
4017 * unused post-migration page and so it has to call
4018 * here with the migration bit still set. See the
4019 * res_counter handling below.
4021 if (!end_migration && PageCgroupMigration(pc))
4024 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
4025 if (!PageAnon(page)) { /* Shared memory */
4026 if (page->mapping && !page_is_file_cache(page))
4028 } else if (page_mapped(page)) /* Anon */
4035 mem_cgroup_charge_statistics(memcg, anon, -nr_pages);
4037 ClearPageCgroupUsed(pc);
4039 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4040 * freed from LRU. This is safe because uncharged page is expected not
4041 * to be reused (freed soon). Exception is SwapCache, it's handled by
4042 * special functions.
4045 unlock_page_cgroup(pc);
4047 * even after unlock, we have memcg->res.usage here and this memcg
4048 * will never be freed.
4050 memcg_check_events(memcg, page);
4051 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
4052 mem_cgroup_swap_statistics(memcg, true);
4053 mem_cgroup_get(memcg);
4056 * Migration does not charge the res_counter for the
4057 * replacement page, so leave it alone when phasing out the
4058 * page that is unused after the migration.
4060 if (!end_migration && !mem_cgroup_is_root(memcg))
4061 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
4066 unlock_page_cgroup(pc);
4070 void mem_cgroup_uncharge_page(struct page *page)
4073 if (page_mapped(page))
4075 VM_BUG_ON(page->mapping && !PageAnon(page));
4076 if (PageSwapCache(page))
4078 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
4081 void mem_cgroup_uncharge_cache_page(struct page *page)
4083 VM_BUG_ON(page_mapped(page));
4084 VM_BUG_ON(page->mapping);
4085 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
4089 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4090 * In that cases, pages are freed continuously and we can expect pages
4091 * are in the same memcg. All these calls itself limits the number of
4092 * pages freed at once, then uncharge_start/end() is called properly.
4093 * This may be called prural(2) times in a context,
4096 void mem_cgroup_uncharge_start(void)
4098 current->memcg_batch.do_batch++;
4099 /* We can do nest. */
4100 if (current->memcg_batch.do_batch == 1) {
4101 current->memcg_batch.memcg = NULL;
4102 current->memcg_batch.nr_pages = 0;
4103 current->memcg_batch.memsw_nr_pages = 0;
4107 void mem_cgroup_uncharge_end(void)
4109 struct memcg_batch_info *batch = ¤t->memcg_batch;
4111 if (!batch->do_batch)
4115 if (batch->do_batch) /* If stacked, do nothing. */
4121 * This "batch->memcg" is valid without any css_get/put etc...
4122 * bacause we hide charges behind us.
4124 if (batch->nr_pages)
4125 res_counter_uncharge(&batch->memcg->res,
4126 batch->nr_pages * PAGE_SIZE);
4127 if (batch->memsw_nr_pages)
4128 res_counter_uncharge(&batch->memcg->memsw,
4129 batch->memsw_nr_pages * PAGE_SIZE);
4130 memcg_oom_recover(batch->memcg);
4131 /* forget this pointer (for sanity check) */
4132 batch->memcg = NULL;
4137 * called after __delete_from_swap_cache() and drop "page" account.
4138 * memcg information is recorded to swap_cgroup of "ent"
4141 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
4143 struct mem_cgroup *memcg;
4144 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4146 if (!swapout) /* this was a swap cache but the swap is unused ! */
4147 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4149 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
4152 * record memcg information, if swapout && memcg != NULL,
4153 * mem_cgroup_get() was called in uncharge().
4155 if (do_swap_account && swapout && memcg)
4156 swap_cgroup_record(ent, css_id(&memcg->css));
4160 #ifdef CONFIG_MEMCG_SWAP
4162 * called from swap_entry_free(). remove record in swap_cgroup and
4163 * uncharge "memsw" account.
4165 void mem_cgroup_uncharge_swap(swp_entry_t ent)
4167 struct mem_cgroup *memcg;
4170 if (!do_swap_account)
4173 id = swap_cgroup_record(ent, 0);
4175 memcg = mem_cgroup_lookup(id);
4178 * We uncharge this because swap is freed.
4179 * This memcg can be obsolete one. We avoid calling css_tryget
4181 if (!mem_cgroup_is_root(memcg))
4182 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
4183 mem_cgroup_swap_statistics(memcg, false);
4184 mem_cgroup_put(memcg);
4190 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4191 * @entry: swap entry to be moved
4192 * @from: mem_cgroup which the entry is moved from
4193 * @to: mem_cgroup which the entry is moved to
4195 * It succeeds only when the swap_cgroup's record for this entry is the same
4196 * as the mem_cgroup's id of @from.
4198 * Returns 0 on success, -EINVAL on failure.
4200 * The caller must have charged to @to, IOW, called res_counter_charge() about
4201 * both res and memsw, and called css_get().
4203 static int mem_cgroup_move_swap_account(swp_entry_t entry,
4204 struct mem_cgroup *from, struct mem_cgroup *to)
4206 unsigned short old_id, new_id;
4208 old_id = css_id(&from->css);
4209 new_id = css_id(&to->css);
4211 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
4212 mem_cgroup_swap_statistics(from, false);
4213 mem_cgroup_swap_statistics(to, true);
4215 * This function is only called from task migration context now.
4216 * It postpones res_counter and refcount handling till the end
4217 * of task migration(mem_cgroup_clear_mc()) for performance
4218 * improvement. But we cannot postpone mem_cgroup_get(to)
4219 * because if the process that has been moved to @to does
4220 * swap-in, the refcount of @to might be decreased to 0.
4228 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
4229 struct mem_cgroup *from, struct mem_cgroup *to)
4236 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4239 void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4240 struct mem_cgroup **memcgp)
4242 struct mem_cgroup *memcg = NULL;
4243 unsigned int nr_pages = 1;
4244 struct page_cgroup *pc;
4245 enum charge_type ctype;
4249 if (mem_cgroup_disabled())
4252 if (PageTransHuge(page))
4253 nr_pages <<= compound_order(page);
4255 pc = lookup_page_cgroup(page);
4256 lock_page_cgroup(pc);
4257 if (PageCgroupUsed(pc)) {
4258 memcg = pc->mem_cgroup;
4259 css_get(&memcg->css);
4261 * At migrating an anonymous page, its mapcount goes down
4262 * to 0 and uncharge() will be called. But, even if it's fully
4263 * unmapped, migration may fail and this page has to be
4264 * charged again. We set MIGRATION flag here and delay uncharge
4265 * until end_migration() is called
4267 * Corner Case Thinking
4269 * When the old page was mapped as Anon and it's unmap-and-freed
4270 * while migration was ongoing.
4271 * If unmap finds the old page, uncharge() of it will be delayed
4272 * until end_migration(). If unmap finds a new page, it's
4273 * uncharged when it make mapcount to be 1->0. If unmap code
4274 * finds swap_migration_entry, the new page will not be mapped
4275 * and end_migration() will find it(mapcount==0).
4278 * When the old page was mapped but migraion fails, the kernel
4279 * remaps it. A charge for it is kept by MIGRATION flag even
4280 * if mapcount goes down to 0. We can do remap successfully
4281 * without charging it again.
4284 * The "old" page is under lock_page() until the end of
4285 * migration, so, the old page itself will not be swapped-out.
4286 * If the new page is swapped out before end_migraton, our
4287 * hook to usual swap-out path will catch the event.
4290 SetPageCgroupMigration(pc);
4292 unlock_page_cgroup(pc);
4294 * If the page is not charged at this point,
4302 * We charge new page before it's used/mapped. So, even if unlock_page()
4303 * is called before end_migration, we can catch all events on this new
4304 * page. In the case new page is migrated but not remapped, new page's
4305 * mapcount will be finally 0 and we call uncharge in end_migration().
4308 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
4310 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
4312 * The page is committed to the memcg, but it's not actually
4313 * charged to the res_counter since we plan on replacing the
4314 * old one and only one page is going to be left afterwards.
4316 __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
4319 /* remove redundant charge if migration failed*/
4320 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
4321 struct page *oldpage, struct page *newpage, bool migration_ok)
4323 struct page *used, *unused;
4324 struct page_cgroup *pc;
4330 if (!migration_ok) {
4337 anon = PageAnon(used);
4338 __mem_cgroup_uncharge_common(unused,
4339 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4340 : MEM_CGROUP_CHARGE_TYPE_CACHE,
4342 css_put(&memcg->css);
4344 * We disallowed uncharge of pages under migration because mapcount
4345 * of the page goes down to zero, temporarly.
4346 * Clear the flag and check the page should be charged.
4348 pc = lookup_page_cgroup(oldpage);
4349 lock_page_cgroup(pc);
4350 ClearPageCgroupMigration(pc);
4351 unlock_page_cgroup(pc);
4354 * If a page is a file cache, radix-tree replacement is very atomic
4355 * and we can skip this check. When it was an Anon page, its mapcount
4356 * goes down to 0. But because we added MIGRATION flage, it's not
4357 * uncharged yet. There are several case but page->mapcount check
4358 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4359 * check. (see prepare_charge() also)
4362 mem_cgroup_uncharge_page(used);
4366 * At replace page cache, newpage is not under any memcg but it's on
4367 * LRU. So, this function doesn't touch res_counter but handles LRU
4368 * in correct way. Both pages are locked so we cannot race with uncharge.
4370 void mem_cgroup_replace_page_cache(struct page *oldpage,
4371 struct page *newpage)
4373 struct mem_cgroup *memcg = NULL;
4374 struct page_cgroup *pc;
4375 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
4377 if (mem_cgroup_disabled())
4380 pc = lookup_page_cgroup(oldpage);
4381 /* fix accounting on old pages */
4382 lock_page_cgroup(pc);
4383 if (PageCgroupUsed(pc)) {
4384 memcg = pc->mem_cgroup;
4385 mem_cgroup_charge_statistics(memcg, false, -1);
4386 ClearPageCgroupUsed(pc);
4388 unlock_page_cgroup(pc);
4391 * When called from shmem_replace_page(), in some cases the
4392 * oldpage has already been charged, and in some cases not.
4397 * Even if newpage->mapping was NULL before starting replacement,
4398 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4399 * LRU while we overwrite pc->mem_cgroup.
4401 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
4404 #ifdef CONFIG_DEBUG_VM
4405 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4407 struct page_cgroup *pc;
4409 pc = lookup_page_cgroup(page);
4411 * Can be NULL while feeding pages into the page allocator for
4412 * the first time, i.e. during boot or memory hotplug;
4413 * or when mem_cgroup_disabled().
4415 if (likely(pc) && PageCgroupUsed(pc))
4420 bool mem_cgroup_bad_page_check(struct page *page)
4422 if (mem_cgroup_disabled())
4425 return lookup_page_cgroup_used(page) != NULL;
4428 void mem_cgroup_print_bad_page(struct page *page)
4430 struct page_cgroup *pc;
4432 pc = lookup_page_cgroup_used(page);
4434 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4435 pc, pc->flags, pc->mem_cgroup);
4440 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
4441 unsigned long long val)
4444 u64 memswlimit, memlimit;
4446 int children = mem_cgroup_count_children(memcg);
4447 u64 curusage, oldusage;
4451 * For keeping hierarchical_reclaim simple, how long we should retry
4452 * is depends on callers. We set our retry-count to be function
4453 * of # of children which we should visit in this loop.
4455 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4457 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4460 while (retry_count) {
4461 if (signal_pending(current)) {
4466 * Rather than hide all in some function, I do this in
4467 * open coded manner. You see what this really does.
4468 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4470 mutex_lock(&set_limit_mutex);
4471 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4472 if (memswlimit < val) {
4474 mutex_unlock(&set_limit_mutex);
4478 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4482 ret = res_counter_set_limit(&memcg->res, val);
4484 if (memswlimit == val)
4485 memcg->memsw_is_minimum = true;
4487 memcg->memsw_is_minimum = false;
4489 mutex_unlock(&set_limit_mutex);
4494 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4495 MEM_CGROUP_RECLAIM_SHRINK);
4496 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4497 /* Usage is reduced ? */
4498 if (curusage >= oldusage)
4501 oldusage = curusage;
4503 if (!ret && enlarge)
4504 memcg_oom_recover(memcg);
4509 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4510 unsigned long long val)
4513 u64 memlimit, memswlimit, oldusage, curusage;
4514 int children = mem_cgroup_count_children(memcg);
4518 /* see mem_cgroup_resize_res_limit */
4519 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
4520 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4521 while (retry_count) {
4522 if (signal_pending(current)) {
4527 * Rather than hide all in some function, I do this in
4528 * open coded manner. You see what this really does.
4529 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4531 mutex_lock(&set_limit_mutex);
4532 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4533 if (memlimit > val) {
4535 mutex_unlock(&set_limit_mutex);
4538 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4539 if (memswlimit < val)
4541 ret = res_counter_set_limit(&memcg->memsw, val);
4543 if (memlimit == val)
4544 memcg->memsw_is_minimum = true;
4546 memcg->memsw_is_minimum = false;
4548 mutex_unlock(&set_limit_mutex);
4553 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4554 MEM_CGROUP_RECLAIM_NOSWAP |
4555 MEM_CGROUP_RECLAIM_SHRINK);
4556 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4557 /* Usage is reduced ? */
4558 if (curusage >= oldusage)
4561 oldusage = curusage;
4563 if (!ret && enlarge)
4564 memcg_oom_recover(memcg);
4568 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
4570 unsigned long *total_scanned)
4572 unsigned long nr_reclaimed = 0;
4573 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
4574 unsigned long reclaimed;
4576 struct mem_cgroup_tree_per_zone *mctz;
4577 unsigned long long excess;
4578 unsigned long nr_scanned;
4583 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
4585 * This loop can run a while, specially if mem_cgroup's continuously
4586 * keep exceeding their soft limit and putting the system under
4593 mz = mem_cgroup_largest_soft_limit_node(mctz);
4598 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
4599 gfp_mask, &nr_scanned);
4600 nr_reclaimed += reclaimed;
4601 *total_scanned += nr_scanned;
4602 spin_lock(&mctz->lock);
4605 * If we failed to reclaim anything from this memory cgroup
4606 * it is time to move on to the next cgroup
4612 * Loop until we find yet another one.
4614 * By the time we get the soft_limit lock
4615 * again, someone might have aded the
4616 * group back on the RB tree. Iterate to
4617 * make sure we get a different mem.
4618 * mem_cgroup_largest_soft_limit_node returns
4619 * NULL if no other cgroup is present on
4623 __mem_cgroup_largest_soft_limit_node(mctz);
4625 css_put(&next_mz->memcg->css);
4626 else /* next_mz == NULL or other memcg */
4630 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
4631 excess = res_counter_soft_limit_excess(&mz->memcg->res);
4633 * One school of thought says that we should not add
4634 * back the node to the tree if reclaim returns 0.
4635 * But our reclaim could return 0, simply because due
4636 * to priority we are exposing a smaller subset of
4637 * memory to reclaim from. Consider this as a longer
4640 /* If excess == 0, no tree ops */
4641 __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess);
4642 spin_unlock(&mctz->lock);
4643 css_put(&mz->memcg->css);
4646 * Could not reclaim anything and there are no more
4647 * mem cgroups to try or we seem to be looping without
4648 * reclaiming anything.
4650 if (!nr_reclaimed &&
4652 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
4654 } while (!nr_reclaimed);
4656 css_put(&next_mz->memcg->css);
4657 return nr_reclaimed;
4661 * mem_cgroup_force_empty_list - clears LRU of a group
4662 * @memcg: group to clear
4665 * @lru: lru to to clear
4667 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4668 * reclaim the pages page themselves - pages are moved to the parent (or root)
4671 static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
4672 int node, int zid, enum lru_list lru)
4674 struct lruvec *lruvec;
4675 unsigned long flags;
4676 struct list_head *list;
4680 zone = &NODE_DATA(node)->node_zones[zid];
4681 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4682 list = &lruvec->lists[lru];
4686 struct page_cgroup *pc;
4689 spin_lock_irqsave(&zone->lru_lock, flags);
4690 if (list_empty(list)) {
4691 spin_unlock_irqrestore(&zone->lru_lock, flags);
4694 page = list_entry(list->prev, struct page, lru);
4696 list_move(&page->lru, list);
4698 spin_unlock_irqrestore(&zone->lru_lock, flags);
4701 spin_unlock_irqrestore(&zone->lru_lock, flags);
4703 pc = lookup_page_cgroup(page);
4705 if (mem_cgroup_move_parent(page, pc, memcg)) {
4706 /* found lock contention or "pc" is obsolete. */
4711 } while (!list_empty(list));
4715 * make mem_cgroup's charge to be 0 if there is no task by moving
4716 * all the charges and pages to the parent.
4717 * This enables deleting this mem_cgroup.
4719 * Caller is responsible for holding css reference on the memcg.
4721 static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
4727 /* This is for making all *used* pages to be on LRU. */
4728 lru_add_drain_all();
4729 drain_all_stock_sync(memcg);
4730 mem_cgroup_start_move(memcg);
4731 for_each_node_state(node, N_MEMORY) {
4732 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4735 mem_cgroup_force_empty_list(memcg,
4740 mem_cgroup_end_move(memcg);
4741 memcg_oom_recover(memcg);
4745 * Kernel memory may not necessarily be trackable to a specific
4746 * process. So they are not migrated, and therefore we can't
4747 * expect their value to drop to 0 here.
4748 * Having res filled up with kmem only is enough.
4750 * This is a safety check because mem_cgroup_force_empty_list
4751 * could have raced with mem_cgroup_replace_page_cache callers
4752 * so the lru seemed empty but the page could have been added
4753 * right after the check. RES_USAGE should be safe as we always
4754 * charge before adding to the LRU.
4756 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4757 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4758 } while (usage > 0);
4762 * This mainly exists for tests during the setting of set of use_hierarchy.
4763 * Since this is the very setting we are changing, the current hierarchy value
4766 static inline bool __memcg_has_children(struct mem_cgroup *memcg)
4770 /* bounce at first found */
4771 cgroup_for_each_child(pos, memcg->css.cgroup)
4777 * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed
4778 * to be already dead (as in mem_cgroup_force_empty, for instance). This is
4779 * from mem_cgroup_count_children(), in the sense that we don't really care how
4780 * many children we have; we only need to know if we have any. It also counts
4781 * any memcg without hierarchy as infertile.
4783 static inline bool memcg_has_children(struct mem_cgroup *memcg)
4785 return memcg->use_hierarchy && __memcg_has_children(memcg);
4789 * Reclaims as many pages from the given memcg as possible and moves
4790 * the rest to the parent.
4792 * Caller is responsible for holding css reference for memcg.
4794 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4796 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4797 struct cgroup *cgrp = memcg->css.cgroup;
4799 /* returns EBUSY if there is a task or if we come here twice. */
4800 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
4803 /* we call try-to-free pages for make this cgroup empty */
4804 lru_add_drain_all();
4805 /* try to free all pages in this cgroup */
4806 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4809 if (signal_pending(current))
4812 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4816 /* maybe some writeback is necessary */
4817 congestion_wait(BLK_RW_ASYNC, HZ/10);
4822 mem_cgroup_reparent_charges(memcg);
4827 static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
4829 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4832 if (mem_cgroup_is_root(memcg))
4834 css_get(&memcg->css);
4835 ret = mem_cgroup_force_empty(memcg);
4836 css_put(&memcg->css);
4842 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
4844 return mem_cgroup_from_cont(cont)->use_hierarchy;
4847 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
4851 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4852 struct cgroup *parent = cont->parent;
4853 struct mem_cgroup *parent_memcg = NULL;
4856 parent_memcg = mem_cgroup_from_cont(parent);
4858 mutex_lock(&memcg_create_mutex);
4860 if (memcg->use_hierarchy == val)
4864 * If parent's use_hierarchy is set, we can't make any modifications
4865 * in the child subtrees. If it is unset, then the change can
4866 * occur, provided the current cgroup has no children.
4868 * For the root cgroup, parent_mem is NULL, we allow value to be
4869 * set if there are no children.
4871 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4872 (val == 1 || val == 0)) {
4873 if (!__memcg_has_children(memcg))
4874 memcg->use_hierarchy = val;
4881 mutex_unlock(&memcg_create_mutex);
4887 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
4888 enum mem_cgroup_stat_index idx)
4890 struct mem_cgroup *iter;
4893 /* Per-cpu values can be negative, use a signed accumulator */
4894 for_each_mem_cgroup_tree(iter, memcg)
4895 val += mem_cgroup_read_stat(iter, idx);
4897 if (val < 0) /* race ? */
4902 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
4906 if (!mem_cgroup_is_root(memcg)) {
4908 return res_counter_read_u64(&memcg->res, RES_USAGE);
4910 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
4913 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
4914 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
4917 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
4919 return val << PAGE_SHIFT;
4922 static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
4923 struct file *file, char __user *buf,
4924 size_t nbytes, loff_t *ppos)
4926 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4932 type = MEMFILE_TYPE(cft->private);
4933 name = MEMFILE_ATTR(cft->private);
4935 if (!do_swap_account && type == _MEMSWAP)
4940 if (name == RES_USAGE)
4941 val = mem_cgroup_usage(memcg, false);
4943 val = res_counter_read_u64(&memcg->res, name);
4946 if (name == RES_USAGE)
4947 val = mem_cgroup_usage(memcg, true);
4949 val = res_counter_read_u64(&memcg->memsw, name);
4952 val = res_counter_read_u64(&memcg->kmem, name);
4958 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
4959 return simple_read_from_buffer(buf, nbytes, ppos, str, len);
4962 static int memcg_update_kmem_limit(struct cgroup *cont, u64 val)
4965 #ifdef CONFIG_MEMCG_KMEM
4966 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4968 * For simplicity, we won't allow this to be disabled. It also can't
4969 * be changed if the cgroup has children already, or if tasks had
4972 * If tasks join before we set the limit, a person looking at
4973 * kmem.usage_in_bytes will have no way to determine when it took
4974 * place, which makes the value quite meaningless.
4976 * After it first became limited, changes in the value of the limit are
4977 * of course permitted.
4979 mutex_lock(&memcg_create_mutex);
4980 mutex_lock(&set_limit_mutex);
4981 if (!memcg->kmem_account_flags && val != RESOURCE_MAX) {
4982 if (cgroup_task_count(cont) || memcg_has_children(memcg)) {
4986 ret = res_counter_set_limit(&memcg->kmem, val);
4989 ret = memcg_update_cache_sizes(memcg);
4991 res_counter_set_limit(&memcg->kmem, RESOURCE_MAX);
4994 static_key_slow_inc(&memcg_kmem_enabled_key);
4996 * setting the active bit after the inc will guarantee no one
4997 * starts accounting before all call sites are patched
4999 memcg_kmem_set_active(memcg);
5002 * kmem charges can outlive the cgroup. In the case of slab
5003 * pages, for instance, a page contain objects from various
5004 * processes, so it is unfeasible to migrate them away. We
5005 * need to reference count the memcg because of that.
5007 mem_cgroup_get(memcg);
5009 ret = res_counter_set_limit(&memcg->kmem, val);
5011 mutex_unlock(&set_limit_mutex);
5012 mutex_unlock(&memcg_create_mutex);
5017 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
5020 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
5024 memcg->kmem_account_flags = parent->kmem_account_flags;
5025 #ifdef CONFIG_MEMCG_KMEM
5027 * When that happen, we need to disable the static branch only on those
5028 * memcgs that enabled it. To achieve this, we would be forced to
5029 * complicate the code by keeping track of which memcgs were the ones
5030 * that actually enabled limits, and which ones got it from its
5033 * It is a lot simpler just to do static_key_slow_inc() on every child
5034 * that is accounted.
5036 if (!memcg_kmem_is_active(memcg))
5040 * destroy(), called if we fail, will issue static_key_slow_inc() and
5041 * mem_cgroup_put() if kmem is enabled. We have to either call them
5042 * unconditionally, or clear the KMEM_ACTIVE flag. I personally find
5043 * this more consistent, since it always leads to the same destroy path
5045 mem_cgroup_get(memcg);
5046 static_key_slow_inc(&memcg_kmem_enabled_key);
5048 mutex_lock(&set_limit_mutex);
5049 ret = memcg_update_cache_sizes(memcg);
5050 mutex_unlock(&set_limit_mutex);
5057 * The user of this function is...
5060 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
5063 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5066 unsigned long long val;
5069 type = MEMFILE_TYPE(cft->private);
5070 name = MEMFILE_ATTR(cft->private);
5072 if (!do_swap_account && type == _MEMSWAP)
5077 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
5081 /* This function does all necessary parse...reuse it */
5082 ret = res_counter_memparse_write_strategy(buffer, &val);
5086 ret = mem_cgroup_resize_limit(memcg, val);
5087 else if (type == _MEMSWAP)
5088 ret = mem_cgroup_resize_memsw_limit(memcg, val);
5089 else if (type == _KMEM)
5090 ret = memcg_update_kmem_limit(cont, val);
5094 case RES_SOFT_LIMIT:
5095 ret = res_counter_memparse_write_strategy(buffer, &val);
5099 * For memsw, soft limits are hard to implement in terms
5100 * of semantics, for now, we support soft limits for
5101 * control without swap
5104 ret = res_counter_set_soft_limit(&memcg->res, val);
5109 ret = -EINVAL; /* should be BUG() ? */
5115 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
5116 unsigned long long *mem_limit, unsigned long long *memsw_limit)
5118 struct cgroup *cgroup;
5119 unsigned long long min_limit, min_memsw_limit, tmp;
5121 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
5122 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
5123 cgroup = memcg->css.cgroup;
5124 if (!memcg->use_hierarchy)
5127 while (cgroup->parent) {
5128 cgroup = cgroup->parent;
5129 memcg = mem_cgroup_from_cont(cgroup);
5130 if (!memcg->use_hierarchy)
5132 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
5133 min_limit = min(min_limit, tmp);
5134 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
5135 min_memsw_limit = min(min_memsw_limit, tmp);
5138 *mem_limit = min_limit;
5139 *memsw_limit = min_memsw_limit;
5142 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
5144 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5148 type = MEMFILE_TYPE(event);
5149 name = MEMFILE_ATTR(event);
5151 if (!do_swap_account && type == _MEMSWAP)
5157 res_counter_reset_max(&memcg->res);
5158 else if (type == _MEMSWAP)
5159 res_counter_reset_max(&memcg->memsw);
5160 else if (type == _KMEM)
5161 res_counter_reset_max(&memcg->kmem);
5167 res_counter_reset_failcnt(&memcg->res);
5168 else if (type == _MEMSWAP)
5169 res_counter_reset_failcnt(&memcg->memsw);
5170 else if (type == _KMEM)
5171 res_counter_reset_failcnt(&memcg->kmem);
5180 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
5183 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
5187 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
5188 struct cftype *cft, u64 val)
5190 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5192 if (val >= (1 << NR_MOVE_TYPE))
5196 * No kind of locking is needed in here, because ->can_attach() will
5197 * check this value once in the beginning of the process, and then carry
5198 * on with stale data. This means that changes to this value will only
5199 * affect task migrations starting after the change.
5201 memcg->move_charge_at_immigrate = val;
5205 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
5206 struct cftype *cft, u64 val)
5213 static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft,
5217 unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
5218 unsigned long node_nr;
5219 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5221 total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL);
5222 seq_printf(m, "total=%lu", total_nr);
5223 for_each_node_state(nid, N_MEMORY) {
5224 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL);
5225 seq_printf(m, " N%d=%lu", nid, node_nr);
5229 file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE);
5230 seq_printf(m, "file=%lu", file_nr);
5231 for_each_node_state(nid, N_MEMORY) {
5232 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5234 seq_printf(m, " N%d=%lu", nid, node_nr);
5238 anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON);
5239 seq_printf(m, "anon=%lu", anon_nr);
5240 for_each_node_state(nid, N_MEMORY) {
5241 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5243 seq_printf(m, " N%d=%lu", nid, node_nr);
5247 unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
5248 seq_printf(m, "unevictable=%lu", unevictable_nr);
5249 for_each_node_state(nid, N_MEMORY) {
5250 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5251 BIT(LRU_UNEVICTABLE));
5252 seq_printf(m, " N%d=%lu", nid, node_nr);
5257 #endif /* CONFIG_NUMA */
5259 static inline void mem_cgroup_lru_names_not_uptodate(void)
5261 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5264 static int memcg_stat_show(struct cgroup *cont, struct cftype *cft,
5267 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5268 struct mem_cgroup *mi;
5271 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5272 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5274 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5275 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
5278 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5279 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5280 mem_cgroup_read_events(memcg, i));
5282 for (i = 0; i < NR_LRU_LISTS; i++)
5283 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5284 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5286 /* Hierarchical information */
5288 unsigned long long limit, memsw_limit;
5289 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
5290 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
5291 if (do_swap_account)
5292 seq_printf(m, "hierarchical_memsw_limit %llu\n",
5296 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5299 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5301 for_each_mem_cgroup_tree(mi, memcg)
5302 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5303 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5306 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5307 unsigned long long val = 0;
5309 for_each_mem_cgroup_tree(mi, memcg)
5310 val += mem_cgroup_read_events(mi, i);
5311 seq_printf(m, "total_%s %llu\n",
5312 mem_cgroup_events_names[i], val);
5315 for (i = 0; i < NR_LRU_LISTS; i++) {
5316 unsigned long long val = 0;
5318 for_each_mem_cgroup_tree(mi, memcg)
5319 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5320 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
5323 #ifdef CONFIG_DEBUG_VM
5326 struct mem_cgroup_per_zone *mz;
5327 struct zone_reclaim_stat *rstat;
5328 unsigned long recent_rotated[2] = {0, 0};
5329 unsigned long recent_scanned[2] = {0, 0};
5331 for_each_online_node(nid)
5332 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
5333 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
5334 rstat = &mz->lruvec.reclaim_stat;
5336 recent_rotated[0] += rstat->recent_rotated[0];
5337 recent_rotated[1] += rstat->recent_rotated[1];
5338 recent_scanned[0] += rstat->recent_scanned[0];
5339 recent_scanned[1] += rstat->recent_scanned[1];
5341 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5342 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5343 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5344 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
5351 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
5353 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5355 return mem_cgroup_swappiness(memcg);
5358 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
5361 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5362 struct mem_cgroup *parent;
5367 if (cgrp->parent == NULL)
5370 parent = mem_cgroup_from_cont(cgrp->parent);
5372 mutex_lock(&memcg_create_mutex);
5374 /* If under hierarchy, only empty-root can set this value */
5375 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5376 mutex_unlock(&memcg_create_mutex);
5380 memcg->swappiness = val;
5382 mutex_unlock(&memcg_create_mutex);
5387 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5389 struct mem_cgroup_threshold_ary *t;
5395 t = rcu_dereference(memcg->thresholds.primary);
5397 t = rcu_dereference(memcg->memsw_thresholds.primary);
5402 usage = mem_cgroup_usage(memcg, swap);
5405 * current_threshold points to threshold just below or equal to usage.
5406 * If it's not true, a threshold was crossed after last
5407 * call of __mem_cgroup_threshold().
5409 i = t->current_threshold;
5412 * Iterate backward over array of thresholds starting from
5413 * current_threshold and check if a threshold is crossed.
5414 * If none of thresholds below usage is crossed, we read
5415 * only one element of the array here.
5417 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5418 eventfd_signal(t->entries[i].eventfd, 1);
5420 /* i = current_threshold + 1 */
5424 * Iterate forward over array of thresholds starting from
5425 * current_threshold+1 and check if a threshold is crossed.
5426 * If none of thresholds above usage is crossed, we read
5427 * only one element of the array here.
5429 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5430 eventfd_signal(t->entries[i].eventfd, 1);
5432 /* Update current_threshold */
5433 t->current_threshold = i - 1;
5438 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5441 __mem_cgroup_threshold(memcg, false);
5442 if (do_swap_account)
5443 __mem_cgroup_threshold(memcg, true);
5445 memcg = parent_mem_cgroup(memcg);
5449 static int compare_thresholds(const void *a, const void *b)
5451 const struct mem_cgroup_threshold *_a = a;
5452 const struct mem_cgroup_threshold *_b = b;
5454 return _a->threshold - _b->threshold;
5457 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
5459 struct mem_cgroup_eventfd_list *ev;
5461 list_for_each_entry(ev, &memcg->oom_notify, list)
5462 eventfd_signal(ev->eventfd, 1);
5466 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
5468 struct mem_cgroup *iter;
5470 for_each_mem_cgroup_tree(iter, memcg)
5471 mem_cgroup_oom_notify_cb(iter);
5474 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
5475 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5477 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5478 struct mem_cgroup_thresholds *thresholds;
5479 struct mem_cgroup_threshold_ary *new;
5480 enum res_type type = MEMFILE_TYPE(cft->private);
5481 u64 threshold, usage;
5484 ret = res_counter_memparse_write_strategy(args, &threshold);
5488 mutex_lock(&memcg->thresholds_lock);
5491 thresholds = &memcg->thresholds;
5492 else if (type == _MEMSWAP)
5493 thresholds = &memcg->memsw_thresholds;
5497 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5499 /* Check if a threshold crossed before adding a new one */
5500 if (thresholds->primary)
5501 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5503 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
5505 /* Allocate memory for new array of thresholds */
5506 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
5514 /* Copy thresholds (if any) to new array */
5515 if (thresholds->primary) {
5516 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
5517 sizeof(struct mem_cgroup_threshold));
5520 /* Add new threshold */
5521 new->entries[size - 1].eventfd = eventfd;
5522 new->entries[size - 1].threshold = threshold;
5524 /* Sort thresholds. Registering of new threshold isn't time-critical */
5525 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
5526 compare_thresholds, NULL);
5528 /* Find current threshold */
5529 new->current_threshold = -1;
5530 for (i = 0; i < size; i++) {
5531 if (new->entries[i].threshold <= usage) {
5533 * new->current_threshold will not be used until
5534 * rcu_assign_pointer(), so it's safe to increment
5537 ++new->current_threshold;
5542 /* Free old spare buffer and save old primary buffer as spare */
5543 kfree(thresholds->spare);
5544 thresholds->spare = thresholds->primary;
5546 rcu_assign_pointer(thresholds->primary, new);
5548 /* To be sure that nobody uses thresholds */
5552 mutex_unlock(&memcg->thresholds_lock);
5557 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
5558 struct cftype *cft, struct eventfd_ctx *eventfd)
5560 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5561 struct mem_cgroup_thresholds *thresholds;
5562 struct mem_cgroup_threshold_ary *new;
5563 enum res_type type = MEMFILE_TYPE(cft->private);
5567 mutex_lock(&memcg->thresholds_lock);
5569 thresholds = &memcg->thresholds;
5570 else if (type == _MEMSWAP)
5571 thresholds = &memcg->memsw_thresholds;
5575 if (!thresholds->primary)
5578 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
5580 /* Check if a threshold crossed before removing */
5581 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5583 /* Calculate new number of threshold */
5585 for (i = 0; i < thresholds->primary->size; i++) {
5586 if (thresholds->primary->entries[i].eventfd != eventfd)
5590 new = thresholds->spare;
5592 /* Set thresholds array to NULL if we don't have thresholds */
5601 /* Copy thresholds and find current threshold */
5602 new->current_threshold = -1;
5603 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5604 if (thresholds->primary->entries[i].eventfd == eventfd)
5607 new->entries[j] = thresholds->primary->entries[i];
5608 if (new->entries[j].threshold <= usage) {
5610 * new->current_threshold will not be used
5611 * until rcu_assign_pointer(), so it's safe to increment
5614 ++new->current_threshold;
5620 /* Swap primary and spare array */
5621 thresholds->spare = thresholds->primary;
5622 /* If all events are unregistered, free the spare array */
5624 kfree(thresholds->spare);
5625 thresholds->spare = NULL;
5628 rcu_assign_pointer(thresholds->primary, new);
5630 /* To be sure that nobody uses thresholds */
5633 mutex_unlock(&memcg->thresholds_lock);
5636 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
5637 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
5639 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5640 struct mem_cgroup_eventfd_list *event;
5641 enum res_type type = MEMFILE_TYPE(cft->private);
5643 BUG_ON(type != _OOM_TYPE);
5644 event = kmalloc(sizeof(*event), GFP_KERNEL);
5648 spin_lock(&memcg_oom_lock);
5650 event->eventfd = eventfd;
5651 list_add(&event->list, &memcg->oom_notify);
5653 /* already in OOM ? */
5654 if (atomic_read(&memcg->under_oom))
5655 eventfd_signal(eventfd, 1);
5656 spin_unlock(&memcg_oom_lock);
5661 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
5662 struct cftype *cft, struct eventfd_ctx *eventfd)
5664 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5665 struct mem_cgroup_eventfd_list *ev, *tmp;
5666 enum res_type type = MEMFILE_TYPE(cft->private);
5668 BUG_ON(type != _OOM_TYPE);
5670 spin_lock(&memcg_oom_lock);
5672 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
5673 if (ev->eventfd == eventfd) {
5674 list_del(&ev->list);
5679 spin_unlock(&memcg_oom_lock);
5682 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
5683 struct cftype *cft, struct cgroup_map_cb *cb)
5685 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5687 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
5689 if (atomic_read(&memcg->under_oom))
5690 cb->fill(cb, "under_oom", 1);
5692 cb->fill(cb, "under_oom", 0);
5696 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
5697 struct cftype *cft, u64 val)
5699 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
5700 struct mem_cgroup *parent;
5702 /* cannot set to root cgroup and only 0 and 1 are allowed */
5703 if (!cgrp->parent || !((val == 0) || (val == 1)))
5706 parent = mem_cgroup_from_cont(cgrp->parent);
5708 mutex_lock(&memcg_create_mutex);
5709 /* oom-kill-disable is a flag for subhierarchy. */
5710 if ((parent->use_hierarchy) || memcg_has_children(memcg)) {
5711 mutex_unlock(&memcg_create_mutex);
5714 memcg->oom_kill_disable = val;
5716 memcg_oom_recover(memcg);
5717 mutex_unlock(&memcg_create_mutex);
5721 #ifdef CONFIG_MEMCG_KMEM
5722 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5726 memcg->kmemcg_id = -1;
5727 ret = memcg_propagate_kmem(memcg);
5731 return mem_cgroup_sockets_init(memcg, ss);
5734 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
5736 mem_cgroup_sockets_destroy(memcg);
5738 memcg_kmem_mark_dead(memcg);
5740 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5744 * Charges already down to 0, undo mem_cgroup_get() done in the charge
5745 * path here, being careful not to race with memcg_uncharge_kmem: it is
5746 * possible that the charges went down to 0 between mark_dead and the
5747 * res_counter read, so in that case, we don't need the put
5749 if (memcg_kmem_test_and_clear_dead(memcg))
5750 mem_cgroup_put(memcg);
5753 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5758 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
5763 static struct cftype mem_cgroup_files[] = {
5765 .name = "usage_in_bytes",
5766 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5767 .read = mem_cgroup_read,
5768 .register_event = mem_cgroup_usage_register_event,
5769 .unregister_event = mem_cgroup_usage_unregister_event,
5772 .name = "max_usage_in_bytes",
5773 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5774 .trigger = mem_cgroup_reset,
5775 .read = mem_cgroup_read,
5778 .name = "limit_in_bytes",
5779 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5780 .write_string = mem_cgroup_write,
5781 .read = mem_cgroup_read,
5784 .name = "soft_limit_in_bytes",
5785 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5786 .write_string = mem_cgroup_write,
5787 .read = mem_cgroup_read,
5791 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5792 .trigger = mem_cgroup_reset,
5793 .read = mem_cgroup_read,
5797 .read_seq_string = memcg_stat_show,
5800 .name = "force_empty",
5801 .trigger = mem_cgroup_force_empty_write,
5804 .name = "use_hierarchy",
5805 .write_u64 = mem_cgroup_hierarchy_write,
5806 .read_u64 = mem_cgroup_hierarchy_read,
5809 .name = "swappiness",
5810 .read_u64 = mem_cgroup_swappiness_read,
5811 .write_u64 = mem_cgroup_swappiness_write,
5814 .name = "move_charge_at_immigrate",
5815 .read_u64 = mem_cgroup_move_charge_read,
5816 .write_u64 = mem_cgroup_move_charge_write,
5819 .name = "oom_control",
5820 .read_map = mem_cgroup_oom_control_read,
5821 .write_u64 = mem_cgroup_oom_control_write,
5822 .register_event = mem_cgroup_oom_register_event,
5823 .unregister_event = mem_cgroup_oom_unregister_event,
5824 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
5828 .name = "numa_stat",
5829 .read_seq_string = memcg_numa_stat_show,
5832 #ifdef CONFIG_MEMCG_KMEM
5834 .name = "kmem.limit_in_bytes",
5835 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5836 .write_string = mem_cgroup_write,
5837 .read = mem_cgroup_read,
5840 .name = "kmem.usage_in_bytes",
5841 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5842 .read = mem_cgroup_read,
5845 .name = "kmem.failcnt",
5846 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5847 .trigger = mem_cgroup_reset,
5848 .read = mem_cgroup_read,
5851 .name = "kmem.max_usage_in_bytes",
5852 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5853 .trigger = mem_cgroup_reset,
5854 .read = mem_cgroup_read,
5856 #ifdef CONFIG_SLABINFO
5858 .name = "kmem.slabinfo",
5859 .read_seq_string = mem_cgroup_slabinfo_read,
5863 { }, /* terminate */
5866 #ifdef CONFIG_MEMCG_SWAP
5867 static struct cftype memsw_cgroup_files[] = {
5869 .name = "memsw.usage_in_bytes",
5870 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
5871 .read = mem_cgroup_read,
5872 .register_event = mem_cgroup_usage_register_event,
5873 .unregister_event = mem_cgroup_usage_unregister_event,
5876 .name = "memsw.max_usage_in_bytes",
5877 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
5878 .trigger = mem_cgroup_reset,
5879 .read = mem_cgroup_read,
5882 .name = "memsw.limit_in_bytes",
5883 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
5884 .write_string = mem_cgroup_write,
5885 .read = mem_cgroup_read,
5888 .name = "memsw.failcnt",
5889 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
5890 .trigger = mem_cgroup_reset,
5891 .read = mem_cgroup_read,
5893 { }, /* terminate */
5896 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5898 struct mem_cgroup_per_node *pn;
5899 struct mem_cgroup_per_zone *mz;
5900 int zone, tmp = node;
5902 * This routine is called against possible nodes.
5903 * But it's BUG to call kmalloc() against offline node.
5905 * TODO: this routine can waste much memory for nodes which will
5906 * never be onlined. It's better to use memory hotplug callback
5909 if (!node_state(node, N_NORMAL_MEMORY))
5911 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
5915 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
5916 mz = &pn->zoneinfo[zone];
5917 lruvec_init(&mz->lruvec);
5918 mz->usage_in_excess = 0;
5919 mz->on_tree = false;
5922 memcg->info.nodeinfo[node] = pn;
5926 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5928 kfree(memcg->info.nodeinfo[node]);
5931 static struct mem_cgroup *mem_cgroup_alloc(void)
5933 struct mem_cgroup *memcg;
5934 size_t size = memcg_size();
5936 /* Can be very big if nr_node_ids is very big */
5937 if (size < PAGE_SIZE)
5938 memcg = kzalloc(size, GFP_KERNEL);
5940 memcg = vzalloc(size);
5945 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
5948 spin_lock_init(&memcg->pcp_counter_lock);
5952 if (size < PAGE_SIZE)
5960 * At destroying mem_cgroup, references from swap_cgroup can remain.
5961 * (scanning all at force_empty is too costly...)
5963 * Instead of clearing all references at force_empty, we remember
5964 * the number of reference from swap_cgroup and free mem_cgroup when
5965 * it goes down to 0.
5967 * Removal of cgroup itself succeeds regardless of refs from swap.
5970 static void __mem_cgroup_free(struct mem_cgroup *memcg)
5973 size_t size = memcg_size();
5975 mem_cgroup_remove_from_trees(memcg);
5976 free_css_id(&mem_cgroup_subsys, &memcg->css);
5979 free_mem_cgroup_per_zone_info(memcg, node);
5981 free_percpu(memcg->stat);
5984 * We need to make sure that (at least for now), the jump label
5985 * destruction code runs outside of the cgroup lock. This is because
5986 * get_online_cpus(), which is called from the static_branch update,
5987 * can't be called inside the cgroup_lock. cpusets are the ones
5988 * enforcing this dependency, so if they ever change, we might as well.
5990 * schedule_work() will guarantee this happens. Be careful if you need
5991 * to move this code around, and make sure it is outside
5994 disarm_static_keys(memcg);
5995 if (size < PAGE_SIZE)
6003 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
6004 * but in process context. The work_freeing structure is overlaid
6005 * on the rcu_freeing structure, which itself is overlaid on memsw.
6007 static void free_work(struct work_struct *work)
6009 struct mem_cgroup *memcg;
6011 memcg = container_of(work, struct mem_cgroup, work_freeing);
6012 __mem_cgroup_free(memcg);
6015 static void free_rcu(struct rcu_head *rcu_head)
6017 struct mem_cgroup *memcg;
6019 memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing);
6020 INIT_WORK(&memcg->work_freeing, free_work);
6021 schedule_work(&memcg->work_freeing);
6024 static void mem_cgroup_get(struct mem_cgroup *memcg)
6026 atomic_inc(&memcg->refcnt);
6029 static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
6031 if (atomic_sub_and_test(count, &memcg->refcnt)) {
6032 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
6033 call_rcu(&memcg->rcu_freeing, free_rcu);
6035 mem_cgroup_put(parent);
6039 static void mem_cgroup_put(struct mem_cgroup *memcg)
6041 __mem_cgroup_put(memcg, 1);
6045 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6047 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
6049 if (!memcg->res.parent)
6051 return mem_cgroup_from_res_counter(memcg->res.parent, res);
6053 EXPORT_SYMBOL(parent_mem_cgroup);
6055 static int mem_cgroup_soft_limit_tree_init(void)
6057 struct mem_cgroup_tree_per_node *rtpn;
6058 struct mem_cgroup_tree_per_zone *rtpz;
6059 int tmp, node, zone;
6061 for_each_node(node) {
6063 if (!node_state(node, N_NORMAL_MEMORY))
6065 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
6069 soft_limit_tree.rb_tree_per_node[node] = rtpn;
6071 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6072 rtpz = &rtpn->rb_tree_per_zone[zone];
6073 rtpz->rb_root = RB_ROOT;
6074 spin_lock_init(&rtpz->lock);
6080 for_each_node(node) {
6081 if (!soft_limit_tree.rb_tree_per_node[node])
6083 kfree(soft_limit_tree.rb_tree_per_node[node]);
6084 soft_limit_tree.rb_tree_per_node[node] = NULL;
6090 static struct cgroup_subsys_state * __ref
6091 mem_cgroup_css_alloc(struct cgroup *cont)
6093 struct mem_cgroup *memcg;
6094 long error = -ENOMEM;
6097 memcg = mem_cgroup_alloc();
6099 return ERR_PTR(error);
6102 if (alloc_mem_cgroup_per_zone_info(memcg, node))
6106 if (cont->parent == NULL) {
6109 if (mem_cgroup_soft_limit_tree_init())
6111 root_mem_cgroup = memcg;
6112 for_each_possible_cpu(cpu) {
6113 struct memcg_stock_pcp *stock =
6114 &per_cpu(memcg_stock, cpu);
6115 INIT_WORK(&stock->work, drain_local_stock);
6118 res_counter_init(&memcg->res, NULL);
6119 res_counter_init(&memcg->memsw, NULL);
6120 res_counter_init(&memcg->kmem, NULL);
6123 memcg->last_scanned_node = MAX_NUMNODES;
6124 INIT_LIST_HEAD(&memcg->oom_notify);
6125 atomic_set(&memcg->refcnt, 1);
6126 memcg->move_charge_at_immigrate = 0;
6127 mutex_init(&memcg->thresholds_lock);
6128 spin_lock_init(&memcg->move_lock);
6133 __mem_cgroup_free(memcg);
6134 return ERR_PTR(error);
6138 mem_cgroup_css_online(struct cgroup *cont)
6140 struct mem_cgroup *memcg, *parent;
6146 mutex_lock(&memcg_create_mutex);
6147 memcg = mem_cgroup_from_cont(cont);
6148 parent = mem_cgroup_from_cont(cont->parent);
6150 memcg->use_hierarchy = parent->use_hierarchy;
6151 memcg->oom_kill_disable = parent->oom_kill_disable;
6152 memcg->swappiness = mem_cgroup_swappiness(parent);
6154 if (parent->use_hierarchy) {
6155 res_counter_init(&memcg->res, &parent->res);
6156 res_counter_init(&memcg->memsw, &parent->memsw);
6157 res_counter_init(&memcg->kmem, &parent->kmem);
6160 * We increment refcnt of the parent to ensure that we can
6161 * safely access it on res_counter_charge/uncharge.
6162 * This refcnt will be decremented when freeing this
6163 * mem_cgroup(see mem_cgroup_put).
6165 mem_cgroup_get(parent);
6167 res_counter_init(&memcg->res, NULL);
6168 res_counter_init(&memcg->memsw, NULL);
6169 res_counter_init(&memcg->kmem, NULL);
6171 * Deeper hierachy with use_hierarchy == false doesn't make
6172 * much sense so let cgroup subsystem know about this
6173 * unfortunate state in our controller.
6175 if (parent != root_mem_cgroup)
6176 mem_cgroup_subsys.broken_hierarchy = true;
6179 error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
6180 mutex_unlock(&memcg_create_mutex);
6183 * We call put now because our (and parent's) refcnts
6184 * are already in place. mem_cgroup_put() will internally
6185 * call __mem_cgroup_free, so return directly
6187 mem_cgroup_put(memcg);
6188 if (parent->use_hierarchy)
6189 mem_cgroup_put(parent);
6194 static void mem_cgroup_css_offline(struct cgroup *cont)
6196 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
6198 mem_cgroup_reparent_charges(memcg);
6199 mem_cgroup_destroy_all_caches(memcg);
6202 static void mem_cgroup_css_free(struct cgroup *cont)
6204 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
6206 kmem_cgroup_destroy(memcg);
6208 mem_cgroup_put(memcg);
6212 /* Handlers for move charge at task migration. */
6213 #define PRECHARGE_COUNT_AT_ONCE 256
6214 static int mem_cgroup_do_precharge(unsigned long count)
6217 int batch_count = PRECHARGE_COUNT_AT_ONCE;
6218 struct mem_cgroup *memcg = mc.to;
6220 if (mem_cgroup_is_root(memcg)) {
6221 mc.precharge += count;
6222 /* we don't need css_get for root */
6225 /* try to charge at once */
6227 struct res_counter *dummy;
6229 * "memcg" cannot be under rmdir() because we've already checked
6230 * by cgroup_lock_live_cgroup() that it is not removed and we
6231 * are still under the same cgroup_mutex. So we can postpone
6234 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
6236 if (do_swap_account && res_counter_charge(&memcg->memsw,
6237 PAGE_SIZE * count, &dummy)) {
6238 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
6241 mc.precharge += count;
6245 /* fall back to one by one charge */
6247 if (signal_pending(current)) {
6251 if (!batch_count--) {
6252 batch_count = PRECHARGE_COUNT_AT_ONCE;
6255 ret = __mem_cgroup_try_charge(NULL,
6256 GFP_KERNEL, 1, &memcg, false);
6258 /* mem_cgroup_clear_mc() will do uncharge later */
6266 * get_mctgt_type - get target type of moving charge
6267 * @vma: the vma the pte to be checked belongs
6268 * @addr: the address corresponding to the pte to be checked
6269 * @ptent: the pte to be checked
6270 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6273 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6274 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6275 * move charge. if @target is not NULL, the page is stored in target->page
6276 * with extra refcnt got(Callers should handle it).
6277 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6278 * target for charge migration. if @target is not NULL, the entry is stored
6281 * Called with pte lock held.
6288 enum mc_target_type {
6294 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6295 unsigned long addr, pte_t ptent)
6297 struct page *page = vm_normal_page(vma, addr, ptent);
6299 if (!page || !page_mapped(page))
6301 if (PageAnon(page)) {
6302 /* we don't move shared anon */
6305 } else if (!move_file())
6306 /* we ignore mapcount for file pages */
6308 if (!get_page_unless_zero(page))
6315 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6316 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6318 struct page *page = NULL;
6319 swp_entry_t ent = pte_to_swp_entry(ptent);
6321 if (!move_anon() || non_swap_entry(ent))
6324 * Because lookup_swap_cache() updates some statistics counter,
6325 * we call find_get_page() with swapper_space directly.
6327 page = find_get_page(swap_address_space(ent), ent.val);
6328 if (do_swap_account)
6329 entry->val = ent.val;
6334 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6335 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6341 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6342 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6344 struct page *page = NULL;
6345 struct address_space *mapping;
6348 if (!vma->vm_file) /* anonymous vma */
6353 mapping = vma->vm_file->f_mapping;
6354 if (pte_none(ptent))
6355 pgoff = linear_page_index(vma, addr);
6356 else /* pte_file(ptent) is true */
6357 pgoff = pte_to_pgoff(ptent);
6359 /* page is moved even if it's not RSS of this task(page-faulted). */
6360 page = find_get_page(mapping, pgoff);
6363 /* shmem/tmpfs may report page out on swap: account for that too. */
6364 if (radix_tree_exceptional_entry(page)) {
6365 swp_entry_t swap = radix_to_swp_entry(page);
6366 if (do_swap_account)
6368 page = find_get_page(swap_address_space(swap), swap.val);
6374 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6375 unsigned long addr, pte_t ptent, union mc_target *target)
6377 struct page *page = NULL;
6378 struct page_cgroup *pc;
6379 enum mc_target_type ret = MC_TARGET_NONE;
6380 swp_entry_t ent = { .val = 0 };
6382 if (pte_present(ptent))
6383 page = mc_handle_present_pte(vma, addr, ptent);
6384 else if (is_swap_pte(ptent))
6385 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
6386 else if (pte_none(ptent) || pte_file(ptent))
6387 page = mc_handle_file_pte(vma, addr, ptent, &ent);
6389 if (!page && !ent.val)
6392 pc = lookup_page_cgroup(page);
6394 * Do only loose check w/o page_cgroup lock.
6395 * mem_cgroup_move_account() checks the pc is valid or not under
6398 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6399 ret = MC_TARGET_PAGE;
6401 target->page = page;
6403 if (!ret || !target)
6406 /* There is a swap entry and a page doesn't exist or isn't charged */
6407 if (ent.val && !ret &&
6408 css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
6409 ret = MC_TARGET_SWAP;
6416 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6418 * We don't consider swapping or file mapped pages because THP does not
6419 * support them for now.
6420 * Caller should make sure that pmd_trans_huge(pmd) is true.
6422 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6423 unsigned long addr, pmd_t pmd, union mc_target *target)
6425 struct page *page = NULL;
6426 struct page_cgroup *pc;
6427 enum mc_target_type ret = MC_TARGET_NONE;
6429 page = pmd_page(pmd);
6430 VM_BUG_ON(!page || !PageHead(page));
6433 pc = lookup_page_cgroup(page);
6434 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6435 ret = MC_TARGET_PAGE;
6438 target->page = page;
6444 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6445 unsigned long addr, pmd_t pmd, union mc_target *target)
6447 return MC_TARGET_NONE;
6451 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6452 unsigned long addr, unsigned long end,
6453 struct mm_walk *walk)
6455 struct vm_area_struct *vma = walk->private;
6459 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6460 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6461 mc.precharge += HPAGE_PMD_NR;
6462 spin_unlock(&vma->vm_mm->page_table_lock);
6466 if (pmd_trans_unstable(pmd))
6468 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6469 for (; addr != end; pte++, addr += PAGE_SIZE)
6470 if (get_mctgt_type(vma, addr, *pte, NULL))
6471 mc.precharge++; /* increment precharge temporarily */
6472 pte_unmap_unlock(pte - 1, ptl);
6478 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6480 unsigned long precharge;
6481 struct vm_area_struct *vma;
6483 down_read(&mm->mmap_sem);
6484 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6485 struct mm_walk mem_cgroup_count_precharge_walk = {
6486 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6490 if (is_vm_hugetlb_page(vma))
6492 walk_page_range(vma->vm_start, vma->vm_end,
6493 &mem_cgroup_count_precharge_walk);
6495 up_read(&mm->mmap_sem);
6497 precharge = mc.precharge;
6503 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6505 unsigned long precharge = mem_cgroup_count_precharge(mm);
6507 VM_BUG_ON(mc.moving_task);
6508 mc.moving_task = current;
6509 return mem_cgroup_do_precharge(precharge);
6512 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6513 static void __mem_cgroup_clear_mc(void)
6515 struct mem_cgroup *from = mc.from;
6516 struct mem_cgroup *to = mc.to;
6518 /* we must uncharge all the leftover precharges from mc.to */
6520 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
6524 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6525 * we must uncharge here.
6527 if (mc.moved_charge) {
6528 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6529 mc.moved_charge = 0;
6531 /* we must fixup refcnts and charges */
6532 if (mc.moved_swap) {
6533 /* uncharge swap account from the old cgroup */
6534 if (!mem_cgroup_is_root(mc.from))
6535 res_counter_uncharge(&mc.from->memsw,
6536 PAGE_SIZE * mc.moved_swap);
6537 __mem_cgroup_put(mc.from, mc.moved_swap);
6539 if (!mem_cgroup_is_root(mc.to)) {
6541 * we charged both to->res and to->memsw, so we should
6544 res_counter_uncharge(&mc.to->res,
6545 PAGE_SIZE * mc.moved_swap);
6547 /* we've already done mem_cgroup_get(mc.to) */
6550 memcg_oom_recover(from);
6551 memcg_oom_recover(to);
6552 wake_up_all(&mc.waitq);
6555 static void mem_cgroup_clear_mc(void)
6557 struct mem_cgroup *from = mc.from;
6560 * we must clear moving_task before waking up waiters at the end of
6563 mc.moving_task = NULL;
6564 __mem_cgroup_clear_mc();
6565 spin_lock(&mc.lock);
6568 spin_unlock(&mc.lock);
6569 mem_cgroup_end_move(from);
6572 static int mem_cgroup_can_attach(struct cgroup *cgroup,
6573 struct cgroup_taskset *tset)
6575 struct task_struct *p = cgroup_taskset_first(tset);
6577 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);
6578 unsigned long move_charge_at_immigrate;
6581 * We are now commited to this value whatever it is. Changes in this
6582 * tunable will only affect upcoming migrations, not the current one.
6583 * So we need to save it, and keep it going.
6585 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6586 if (move_charge_at_immigrate) {
6587 struct mm_struct *mm;
6588 struct mem_cgroup *from = mem_cgroup_from_task(p);
6590 VM_BUG_ON(from == memcg);
6592 mm = get_task_mm(p);
6595 /* We move charges only when we move a owner of the mm */
6596 if (mm->owner == p) {
6599 VM_BUG_ON(mc.precharge);
6600 VM_BUG_ON(mc.moved_charge);
6601 VM_BUG_ON(mc.moved_swap);
6602 mem_cgroup_start_move(from);
6603 spin_lock(&mc.lock);
6606 mc.immigrate_flags = move_charge_at_immigrate;
6607 spin_unlock(&mc.lock);
6608 /* We set mc.moving_task later */
6610 ret = mem_cgroup_precharge_mc(mm);
6612 mem_cgroup_clear_mc();
6619 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
6620 struct cgroup_taskset *tset)
6622 mem_cgroup_clear_mc();
6625 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6626 unsigned long addr, unsigned long end,
6627 struct mm_walk *walk)
6630 struct vm_area_struct *vma = walk->private;
6633 enum mc_target_type target_type;
6634 union mc_target target;
6636 struct page_cgroup *pc;
6639 * We don't take compound_lock() here but no race with splitting thp
6641 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6642 * under splitting, which means there's no concurrent thp split,
6643 * - if another thread runs into split_huge_page() just after we
6644 * entered this if-block, the thread must wait for page table lock
6645 * to be unlocked in __split_huge_page_splitting(), where the main
6646 * part of thp split is not executed yet.
6648 if (pmd_trans_huge_lock(pmd, vma) == 1) {
6649 if (mc.precharge < HPAGE_PMD_NR) {
6650 spin_unlock(&vma->vm_mm->page_table_lock);
6653 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6654 if (target_type == MC_TARGET_PAGE) {
6656 if (!isolate_lru_page(page)) {
6657 pc = lookup_page_cgroup(page);
6658 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6659 pc, mc.from, mc.to)) {
6660 mc.precharge -= HPAGE_PMD_NR;
6661 mc.moved_charge += HPAGE_PMD_NR;
6663 putback_lru_page(page);
6667 spin_unlock(&vma->vm_mm->page_table_lock);
6671 if (pmd_trans_unstable(pmd))
6674 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6675 for (; addr != end; addr += PAGE_SIZE) {
6676 pte_t ptent = *(pte++);
6682 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6683 case MC_TARGET_PAGE:
6685 if (isolate_lru_page(page))
6687 pc = lookup_page_cgroup(page);
6688 if (!mem_cgroup_move_account(page, 1, pc,
6691 /* we uncharge from mc.from later. */
6694 putback_lru_page(page);
6695 put: /* get_mctgt_type() gets the page */
6698 case MC_TARGET_SWAP:
6700 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6702 /* we fixup refcnts and charges later. */
6710 pte_unmap_unlock(pte - 1, ptl);
6715 * We have consumed all precharges we got in can_attach().
6716 * We try charge one by one, but don't do any additional
6717 * charges to mc.to if we have failed in charge once in attach()
6720 ret = mem_cgroup_do_precharge(1);
6728 static void mem_cgroup_move_charge(struct mm_struct *mm)
6730 struct vm_area_struct *vma;
6732 lru_add_drain_all();
6734 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6736 * Someone who are holding the mmap_sem might be waiting in
6737 * waitq. So we cancel all extra charges, wake up all waiters,
6738 * and retry. Because we cancel precharges, we might not be able
6739 * to move enough charges, but moving charge is a best-effort
6740 * feature anyway, so it wouldn't be a big problem.
6742 __mem_cgroup_clear_mc();
6746 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6748 struct mm_walk mem_cgroup_move_charge_walk = {
6749 .pmd_entry = mem_cgroup_move_charge_pte_range,
6753 if (is_vm_hugetlb_page(vma))
6755 ret = walk_page_range(vma->vm_start, vma->vm_end,
6756 &mem_cgroup_move_charge_walk);
6759 * means we have consumed all precharges and failed in
6760 * doing additional charge. Just abandon here.
6764 up_read(&mm->mmap_sem);
6767 static void mem_cgroup_move_task(struct cgroup *cont,
6768 struct cgroup_taskset *tset)
6770 struct task_struct *p = cgroup_taskset_first(tset);
6771 struct mm_struct *mm = get_task_mm(p);
6775 mem_cgroup_move_charge(mm);
6779 mem_cgroup_clear_mc();
6781 #else /* !CONFIG_MMU */
6782 static int mem_cgroup_can_attach(struct cgroup *cgroup,
6783 struct cgroup_taskset *tset)
6787 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
6788 struct cgroup_taskset *tset)
6791 static void mem_cgroup_move_task(struct cgroup *cont,
6792 struct cgroup_taskset *tset)
6797 struct cgroup_subsys mem_cgroup_subsys = {
6799 .subsys_id = mem_cgroup_subsys_id,
6800 .css_alloc = mem_cgroup_css_alloc,
6801 .css_online = mem_cgroup_css_online,
6802 .css_offline = mem_cgroup_css_offline,
6803 .css_free = mem_cgroup_css_free,
6804 .can_attach = mem_cgroup_can_attach,
6805 .cancel_attach = mem_cgroup_cancel_attach,
6806 .attach = mem_cgroup_move_task,
6807 .base_cftypes = mem_cgroup_files,
6812 #ifdef CONFIG_MEMCG_SWAP
6813 static int __init enable_swap_account(char *s)
6815 /* consider enabled if no parameter or 1 is given */
6816 if (!strcmp(s, "1"))
6817 really_do_swap_account = 1;
6818 else if (!strcmp(s, "0"))
6819 really_do_swap_account = 0;
6822 __setup("swapaccount=", enable_swap_account);
6824 static void __init memsw_file_init(void)
6826 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys, memsw_cgroup_files));
6829 static void __init enable_swap_cgroup(void)
6831 if (!mem_cgroup_disabled() && really_do_swap_account) {
6832 do_swap_account = 1;
6838 static void __init enable_swap_cgroup(void)
6844 * The rest of init is performed during ->css_alloc() for root css which
6845 * happens before initcalls. hotcpu_notifier() can't be done together as
6846 * it would introduce circular locking by adding cgroup_lock -> cpu hotplug
6847 * dependency. Do it from a subsys_initcall().
6849 static int __init mem_cgroup_init(void)
6851 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6852 enable_swap_cgroup();
6855 subsys_initcall(mem_cgroup_init);