1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
28 #include <linux/res_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
32 #include <linux/hugetlb.h>
33 #include <linux/pagemap.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/page_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
62 #include <net/tcp_memcontrol.h>
65 #include <asm/uaccess.h>
67 #include <trace/events/vmscan.h>
69 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
70 EXPORT_SYMBOL(memory_cgrp_subsys);
72 #define MEM_CGROUP_RECLAIM_RETRIES 5
73 static struct mem_cgroup *root_mem_cgroup __read_mostly;
75 #ifdef CONFIG_MEMCG_SWAP
76 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
77 int do_swap_account __read_mostly;
79 /* for remember boot option*/
80 #ifdef CONFIG_MEMCG_SWAP_ENABLED
81 static int really_do_swap_account __initdata = 1;
83 static int really_do_swap_account __initdata;
87 #define do_swap_account 0
91 static const char * const mem_cgroup_stat_names[] = {
100 enum mem_cgroup_events_index {
101 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
102 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
103 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
104 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
105 MEM_CGROUP_EVENTS_NSTATS,
108 static const char * const mem_cgroup_events_names[] = {
115 static const char * const mem_cgroup_lru_names[] = {
124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
125 * it will be incremated by the number of pages. This counter is used for
126 * for trigger some periodic events. This is straightforward and better
127 * than using jiffies etc. to handle periodic memcg event.
129 enum mem_cgroup_events_target {
130 MEM_CGROUP_TARGET_THRESH,
131 MEM_CGROUP_TARGET_SOFTLIMIT,
132 MEM_CGROUP_TARGET_NUMAINFO,
135 #define THRESHOLDS_EVENTS_TARGET 128
136 #define SOFTLIMIT_EVENTS_TARGET 1024
137 #define NUMAINFO_EVENTS_TARGET 1024
139 struct mem_cgroup_stat_cpu {
140 long count[MEM_CGROUP_STAT_NSTATS];
141 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
142 unsigned long nr_page_events;
143 unsigned long targets[MEM_CGROUP_NTARGETS];
146 struct mem_cgroup_reclaim_iter {
148 * last scanned hierarchy member. Valid only if last_dead_count
149 * matches memcg->dead_count of the hierarchy root group.
151 struct mem_cgroup *last_visited;
154 /* scan generation, increased every round-trip */
155 unsigned int generation;
159 * per-zone information in memory controller.
161 struct mem_cgroup_per_zone {
162 struct lruvec lruvec;
163 unsigned long lru_size[NR_LRU_LISTS];
165 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
167 struct rb_node tree_node; /* RB tree node */
168 unsigned long long usage_in_excess;/* Set to the value by which */
169 /* the soft limit is exceeded*/
171 struct mem_cgroup *memcg; /* Back pointer, we cannot */
172 /* use container_of */
175 struct mem_cgroup_per_node {
176 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
180 * Cgroups above their limits are maintained in a RB-Tree, independent of
181 * their hierarchy representation
184 struct mem_cgroup_tree_per_zone {
185 struct rb_root rb_root;
189 struct mem_cgroup_tree_per_node {
190 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
193 struct mem_cgroup_tree {
194 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
197 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
199 struct mem_cgroup_threshold {
200 struct eventfd_ctx *eventfd;
205 struct mem_cgroup_threshold_ary {
206 /* An array index points to threshold just below or equal to usage. */
207 int current_threshold;
208 /* Size of entries[] */
210 /* Array of thresholds */
211 struct mem_cgroup_threshold entries[0];
214 struct mem_cgroup_thresholds {
215 /* Primary thresholds array */
216 struct mem_cgroup_threshold_ary *primary;
218 * Spare threshold array.
219 * This is needed to make mem_cgroup_unregister_event() "never fail".
220 * It must be able to store at least primary->size - 1 entries.
222 struct mem_cgroup_threshold_ary *spare;
226 struct mem_cgroup_eventfd_list {
227 struct list_head list;
228 struct eventfd_ctx *eventfd;
232 * cgroup_event represents events which userspace want to receive.
234 struct mem_cgroup_event {
236 * memcg which the event belongs to.
238 struct mem_cgroup *memcg;
240 * eventfd to signal userspace about the event.
242 struct eventfd_ctx *eventfd;
244 * Each of these stored in a list by the cgroup.
246 struct list_head list;
248 * register_event() callback will be used to add new userspace
249 * waiter for changes related to this event. Use eventfd_signal()
250 * on eventfd to send notification to userspace.
252 int (*register_event)(struct mem_cgroup *memcg,
253 struct eventfd_ctx *eventfd, const char *args);
255 * unregister_event() callback will be called when userspace closes
256 * the eventfd or on cgroup removing. This callback must be set,
257 * if you want provide notification functionality.
259 void (*unregister_event)(struct mem_cgroup *memcg,
260 struct eventfd_ctx *eventfd);
262 * All fields below needed to unregister event when
263 * userspace closes eventfd.
266 wait_queue_head_t *wqh;
268 struct work_struct remove;
271 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
272 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
275 * The memory controller data structure. The memory controller controls both
276 * page cache and RSS per cgroup. We would eventually like to provide
277 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
278 * to help the administrator determine what knobs to tune.
280 * TODO: Add a water mark for the memory controller. Reclaim will begin when
281 * we hit the water mark. May be even add a low water mark, such that
282 * no reclaim occurs from a cgroup at it's low water mark, this is
283 * a feature that will be implemented much later in the future.
286 struct cgroup_subsys_state css;
288 * the counter to account for memory usage
290 struct res_counter res;
292 /* vmpressure notifications */
293 struct vmpressure vmpressure;
296 * the counter to account for mem+swap usage.
298 struct res_counter memsw;
301 * the counter to account for kernel memory usage.
303 struct res_counter kmem;
305 * Should the accounting and control be hierarchical, per subtree?
308 unsigned long kmem_account_flags; /* See KMEM_ACCOUNTED_*, below */
312 atomic_t oom_wakeups;
315 /* OOM-Killer disable */
316 int oom_kill_disable;
318 /* set when res.limit == memsw.limit */
319 bool memsw_is_minimum;
321 /* protect arrays of thresholds */
322 struct mutex thresholds_lock;
324 /* thresholds for memory usage. RCU-protected */
325 struct mem_cgroup_thresholds thresholds;
327 /* thresholds for mem+swap usage. RCU-protected */
328 struct mem_cgroup_thresholds memsw_thresholds;
330 /* For oom notifier event fd */
331 struct list_head oom_notify;
334 * Should we move charges of a task when a task is moved into this
335 * mem_cgroup ? And what type of charges should we move ?
337 unsigned long move_charge_at_immigrate;
339 * set > 0 if pages under this cgroup are moving to other cgroup.
341 atomic_t moving_account;
342 /* taken only while moving_account > 0 */
343 spinlock_t move_lock;
347 struct mem_cgroup_stat_cpu __percpu *stat;
349 * used when a cpu is offlined or other synchronizations
350 * See mem_cgroup_read_stat().
352 struct mem_cgroup_stat_cpu nocpu_base;
353 spinlock_t pcp_counter_lock;
356 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
357 struct cg_proto tcp_mem;
359 #if defined(CONFIG_MEMCG_KMEM)
360 /* analogous to slab_common's slab_caches list, but per-memcg;
361 * protected by memcg_slab_mutex */
362 struct list_head memcg_slab_caches;
363 /* Index in the kmem_cache->memcg_params->memcg_caches array */
367 int last_scanned_node;
369 nodemask_t scan_nodes;
370 atomic_t numainfo_events;
371 atomic_t numainfo_updating;
374 /* List of events which userspace want to receive */
375 struct list_head event_list;
376 spinlock_t event_list_lock;
378 struct mem_cgroup_per_node *nodeinfo[0];
379 /* WARNING: nodeinfo must be the last member here */
382 /* internal only representation about the status of kmem accounting. */
384 KMEM_ACCOUNTED_ACTIVE, /* accounted by this cgroup itself */
385 KMEM_ACCOUNTED_DEAD, /* dead memcg with pending kmem charges */
388 #ifdef CONFIG_MEMCG_KMEM
389 static inline void memcg_kmem_set_active(struct mem_cgroup *memcg)
391 set_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
394 static bool memcg_kmem_is_active(struct mem_cgroup *memcg)
396 return test_bit(KMEM_ACCOUNTED_ACTIVE, &memcg->kmem_account_flags);
399 static void memcg_kmem_mark_dead(struct mem_cgroup *memcg)
402 * Our caller must use css_get() first, because memcg_uncharge_kmem()
403 * will call css_put() if it sees the memcg is dead.
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 struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *s)
500 return s ? container_of(s, struct mem_cgroup, css) : NULL;
503 /* Some nice accessors for the vmpressure. */
504 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
507 memcg = root_mem_cgroup;
508 return &memcg->vmpressure;
511 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
513 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
516 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
518 return (memcg == root_mem_cgroup);
522 * We restrict the id in the range of [1, 65535], so it can fit into
525 #define MEM_CGROUP_ID_MAX USHRT_MAX
527 static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
529 return memcg->css.id;
532 static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
534 struct cgroup_subsys_state *css;
536 css = css_from_id(id, &memory_cgrp_subsys);
537 return mem_cgroup_from_css(css);
540 /* Writing them here to avoid exposing memcg's inner layout */
541 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
543 void sock_update_memcg(struct sock *sk)
545 if (mem_cgroup_sockets_enabled) {
546 struct mem_cgroup *memcg;
547 struct cg_proto *cg_proto;
549 BUG_ON(!sk->sk_prot->proto_cgroup);
551 /* Socket cloning can throw us here with sk_cgrp already
552 * filled. It won't however, necessarily happen from
553 * process context. So the test for root memcg given
554 * the current task's memcg won't help us in this case.
556 * Respecting the original socket's memcg is a better
557 * decision in this case.
560 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
561 css_get(&sk->sk_cgrp->memcg->css);
566 memcg = mem_cgroup_from_task(current);
567 cg_proto = sk->sk_prot->proto_cgroup(memcg);
568 if (!mem_cgroup_is_root(memcg) &&
569 memcg_proto_active(cg_proto) &&
570 css_tryget_online(&memcg->css)) {
571 sk->sk_cgrp = cg_proto;
576 EXPORT_SYMBOL(sock_update_memcg);
578 void sock_release_memcg(struct sock *sk)
580 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
581 struct mem_cgroup *memcg;
582 WARN_ON(!sk->sk_cgrp->memcg);
583 memcg = sk->sk_cgrp->memcg;
584 css_put(&sk->sk_cgrp->memcg->css);
588 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
590 if (!memcg || mem_cgroup_is_root(memcg))
593 return &memcg->tcp_mem;
595 EXPORT_SYMBOL(tcp_proto_cgroup);
597 static void disarm_sock_keys(struct mem_cgroup *memcg)
599 if (!memcg_proto_activated(&memcg->tcp_mem))
601 static_key_slow_dec(&memcg_socket_limit_enabled);
604 static void disarm_sock_keys(struct mem_cgroup *memcg)
609 #ifdef CONFIG_MEMCG_KMEM
611 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
612 * The main reason for not using cgroup id for this:
613 * this works better in sparse environments, where we have a lot of memcgs,
614 * but only a few kmem-limited. Or also, if we have, for instance, 200
615 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
616 * 200 entry array for that.
618 * The current size of the caches array is stored in
619 * memcg_limited_groups_array_size. It will double each time we have to
622 static DEFINE_IDA(kmem_limited_groups);
623 int memcg_limited_groups_array_size;
626 * MIN_SIZE is different than 1, because we would like to avoid going through
627 * the alloc/free process all the time. In a small machine, 4 kmem-limited
628 * cgroups is a reasonable guess. In the future, it could be a parameter or
629 * tunable, but that is strictly not necessary.
631 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
632 * this constant directly from cgroup, but it is understandable that this is
633 * better kept as an internal representation in cgroup.c. In any case, the
634 * cgrp_id space is not getting any smaller, and we don't have to necessarily
635 * increase ours as well if it increases.
637 #define MEMCG_CACHES_MIN_SIZE 4
638 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
641 * A lot of the calls to the cache allocation functions are expected to be
642 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
643 * conditional to this static branch, we'll have to allow modules that does
644 * kmem_cache_alloc and the such to see this symbol as well
646 struct static_key memcg_kmem_enabled_key;
647 EXPORT_SYMBOL(memcg_kmem_enabled_key);
649 static void disarm_kmem_keys(struct mem_cgroup *memcg)
651 if (memcg_kmem_is_active(memcg)) {
652 static_key_slow_dec(&memcg_kmem_enabled_key);
653 ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
656 * This check can't live in kmem destruction function,
657 * since the charges will outlive the cgroup
659 WARN_ON(res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0);
662 static void disarm_kmem_keys(struct mem_cgroup *memcg)
665 #endif /* CONFIG_MEMCG_KMEM */
667 static void disarm_static_keys(struct mem_cgroup *memcg)
669 disarm_sock_keys(memcg);
670 disarm_kmem_keys(memcg);
673 static void drain_all_stock_async(struct mem_cgroup *memcg);
675 static struct mem_cgroup_per_zone *
676 mem_cgroup_zone_zoneinfo(struct mem_cgroup *memcg, struct zone *zone)
678 int nid = zone_to_nid(zone);
679 int zid = zone_idx(zone);
681 return &memcg->nodeinfo[nid]->zoneinfo[zid];
684 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
689 static struct mem_cgroup_per_zone *
690 mem_cgroup_page_zoneinfo(struct mem_cgroup *memcg, struct page *page)
692 int nid = page_to_nid(page);
693 int zid = page_zonenum(page);
695 return &memcg->nodeinfo[nid]->zoneinfo[zid];
698 static struct mem_cgroup_tree_per_zone *
699 soft_limit_tree_node_zone(int nid, int zid)
701 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
704 static struct mem_cgroup_tree_per_zone *
705 soft_limit_tree_from_page(struct page *page)
707 int nid = page_to_nid(page);
708 int zid = page_zonenum(page);
710 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
713 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone *mz,
714 struct mem_cgroup_tree_per_zone *mctz,
715 unsigned long long new_usage_in_excess)
717 struct rb_node **p = &mctz->rb_root.rb_node;
718 struct rb_node *parent = NULL;
719 struct mem_cgroup_per_zone *mz_node;
724 mz->usage_in_excess = new_usage_in_excess;
725 if (!mz->usage_in_excess)
729 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
731 if (mz->usage_in_excess < mz_node->usage_in_excess)
734 * We can't avoid mem cgroups that are over their soft
735 * limit by the same amount
737 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
740 rb_link_node(&mz->tree_node, parent, p);
741 rb_insert_color(&mz->tree_node, &mctz->rb_root);
745 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
746 struct mem_cgroup_tree_per_zone *mctz)
750 rb_erase(&mz->tree_node, &mctz->rb_root);
754 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone *mz,
755 struct mem_cgroup_tree_per_zone *mctz)
757 spin_lock(&mctz->lock);
758 __mem_cgroup_remove_exceeded(mz, mctz);
759 spin_unlock(&mctz->lock);
763 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
765 unsigned long long excess;
766 struct mem_cgroup_per_zone *mz;
767 struct mem_cgroup_tree_per_zone *mctz;
769 mctz = soft_limit_tree_from_page(page);
771 * Necessary to update all ancestors when hierarchy is used.
772 * because their event counter is not touched.
774 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
775 mz = mem_cgroup_page_zoneinfo(memcg, page);
776 excess = res_counter_soft_limit_excess(&memcg->res);
778 * We have to update the tree if mz is on RB-tree or
779 * mem is over its softlimit.
781 if (excess || mz->on_tree) {
782 spin_lock(&mctz->lock);
783 /* if on-tree, remove it */
785 __mem_cgroup_remove_exceeded(mz, mctz);
787 * Insert again. mz->usage_in_excess will be updated.
788 * If excess is 0, no tree ops.
790 __mem_cgroup_insert_exceeded(mz, mctz, excess);
791 spin_unlock(&mctz->lock);
796 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
798 struct mem_cgroup_tree_per_zone *mctz;
799 struct mem_cgroup_per_zone *mz;
803 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
804 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
805 mctz = soft_limit_tree_node_zone(nid, zid);
806 mem_cgroup_remove_exceeded(mz, mctz);
811 static struct mem_cgroup_per_zone *
812 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
814 struct rb_node *rightmost = NULL;
815 struct mem_cgroup_per_zone *mz;
819 rightmost = rb_last(&mctz->rb_root);
821 goto done; /* Nothing to reclaim from */
823 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
825 * Remove the node now but someone else can add it back,
826 * we will to add it back at the end of reclaim to its correct
827 * position in the tree.
829 __mem_cgroup_remove_exceeded(mz, mctz);
830 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
831 !css_tryget_online(&mz->memcg->css))
837 static struct mem_cgroup_per_zone *
838 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
840 struct mem_cgroup_per_zone *mz;
842 spin_lock(&mctz->lock);
843 mz = __mem_cgroup_largest_soft_limit_node(mctz);
844 spin_unlock(&mctz->lock);
849 * Implementation Note: reading percpu statistics for memcg.
851 * Both of vmstat[] and percpu_counter has threshold and do periodic
852 * synchronization to implement "quick" read. There are trade-off between
853 * reading cost and precision of value. Then, we may have a chance to implement
854 * a periodic synchronizion of counter in memcg's counter.
856 * But this _read() function is used for user interface now. The user accounts
857 * memory usage by memory cgroup and he _always_ requires exact value because
858 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
859 * have to visit all online cpus and make sum. So, for now, unnecessary
860 * synchronization is not implemented. (just implemented for cpu hotplug)
862 * If there are kernel internal actions which can make use of some not-exact
863 * value, and reading all cpu value can be performance bottleneck in some
864 * common workload, threashold and synchonization as vmstat[] should be
867 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
868 enum mem_cgroup_stat_index idx)
874 for_each_online_cpu(cpu)
875 val += per_cpu(memcg->stat->count[idx], cpu);
876 #ifdef CONFIG_HOTPLUG_CPU
877 spin_lock(&memcg->pcp_counter_lock);
878 val += memcg->nocpu_base.count[idx];
879 spin_unlock(&memcg->pcp_counter_lock);
885 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
888 int val = (charge) ? 1 : -1;
889 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
892 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
893 enum mem_cgroup_events_index idx)
895 unsigned long val = 0;
899 for_each_online_cpu(cpu)
900 val += per_cpu(memcg->stat->events[idx], cpu);
901 #ifdef CONFIG_HOTPLUG_CPU
902 spin_lock(&memcg->pcp_counter_lock);
903 val += memcg->nocpu_base.events[idx];
904 spin_unlock(&memcg->pcp_counter_lock);
910 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
912 bool anon, int nr_pages)
915 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
916 * counted as CACHE even if it's on ANON LRU.
919 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
922 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
925 if (PageTransHuge(page))
926 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
929 /* pagein of a big page is an event. So, ignore page size */
931 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
933 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
934 nr_pages = -nr_pages; /* for event */
937 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
940 unsigned long mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
942 struct mem_cgroup_per_zone *mz;
944 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
945 return mz->lru_size[lru];
948 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
950 unsigned int lru_mask)
952 unsigned long nr = 0;
955 VM_BUG_ON((unsigned)nid >= nr_node_ids);
957 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
958 struct mem_cgroup_per_zone *mz;
962 if (!(BIT(lru) & lru_mask))
964 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
965 nr += mz->lru_size[lru];
971 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
972 unsigned int lru_mask)
974 unsigned long nr = 0;
977 for_each_node_state(nid, N_MEMORY)
978 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
982 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
983 enum mem_cgroup_events_target target)
985 unsigned long val, next;
987 val = __this_cpu_read(memcg->stat->nr_page_events);
988 next = __this_cpu_read(memcg->stat->targets[target]);
989 /* from time_after() in jiffies.h */
990 if ((long)next - (long)val < 0) {
992 case MEM_CGROUP_TARGET_THRESH:
993 next = val + THRESHOLDS_EVENTS_TARGET;
995 case MEM_CGROUP_TARGET_SOFTLIMIT:
996 next = val + SOFTLIMIT_EVENTS_TARGET;
998 case MEM_CGROUP_TARGET_NUMAINFO:
999 next = val + NUMAINFO_EVENTS_TARGET;
1004 __this_cpu_write(memcg->stat->targets[target], next);
1011 * Check events in order.
1014 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
1017 /* threshold event is triggered in finer grain than soft limit */
1018 if (unlikely(mem_cgroup_event_ratelimit(memcg,
1019 MEM_CGROUP_TARGET_THRESH))) {
1021 bool do_numainfo __maybe_unused;
1023 do_softlimit = mem_cgroup_event_ratelimit(memcg,
1024 MEM_CGROUP_TARGET_SOFTLIMIT);
1025 #if MAX_NUMNODES > 1
1026 do_numainfo = mem_cgroup_event_ratelimit(memcg,
1027 MEM_CGROUP_TARGET_NUMAINFO);
1031 mem_cgroup_threshold(memcg);
1032 if (unlikely(do_softlimit))
1033 mem_cgroup_update_tree(memcg, page);
1034 #if MAX_NUMNODES > 1
1035 if (unlikely(do_numainfo))
1036 atomic_inc(&memcg->numainfo_events);
1042 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
1045 * mm_update_next_owner() may clear mm->owner to NULL
1046 * if it races with swapoff, page migration, etc.
1047 * So this can be called with p == NULL.
1052 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
1055 static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
1057 struct mem_cgroup *memcg = NULL;
1062 * Page cache insertions can happen withou an
1063 * actual mm context, e.g. during disk probing
1064 * on boot, loopback IO, acct() writes etc.
1067 memcg = root_mem_cgroup;
1069 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1070 if (unlikely(!memcg))
1071 memcg = root_mem_cgroup;
1073 } while (!css_tryget_online(&memcg->css));
1079 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1080 * ref. count) or NULL if the whole root's subtree has been visited.
1082 * helper function to be used by mem_cgroup_iter
1084 static struct mem_cgroup *__mem_cgroup_iter_next(struct mem_cgroup *root,
1085 struct mem_cgroup *last_visited)
1087 struct cgroup_subsys_state *prev_css, *next_css;
1089 prev_css = last_visited ? &last_visited->css : NULL;
1091 next_css = css_next_descendant_pre(prev_css, &root->css);
1094 * Even if we found a group we have to make sure it is
1095 * alive. css && !memcg means that the groups should be
1096 * skipped and we should continue the tree walk.
1097 * last_visited css is safe to use because it is
1098 * protected by css_get and the tree walk is rcu safe.
1100 * We do not take a reference on the root of the tree walk
1101 * because we might race with the root removal when it would
1102 * be the only node in the iterated hierarchy and mem_cgroup_iter
1103 * would end up in an endless loop because it expects that at
1104 * least one valid node will be returned. Root cannot disappear
1105 * because caller of the iterator should hold it already so
1106 * skipping css reference should be safe.
1109 if ((next_css == &root->css) ||
1110 ((next_css->flags & CSS_ONLINE) &&
1111 css_tryget_online(next_css)))
1112 return mem_cgroup_from_css(next_css);
1114 prev_css = next_css;
1121 static void mem_cgroup_iter_invalidate(struct mem_cgroup *root)
1124 * When a group in the hierarchy below root is destroyed, the
1125 * hierarchy iterator can no longer be trusted since it might
1126 * have pointed to the destroyed group. Invalidate it.
1128 atomic_inc(&root->dead_count);
1131 static struct mem_cgroup *
1132 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter *iter,
1133 struct mem_cgroup *root,
1136 struct mem_cgroup *position = NULL;
1138 * A cgroup destruction happens in two stages: offlining and
1139 * release. They are separated by a RCU grace period.
1141 * If the iterator is valid, we may still race with an
1142 * offlining. The RCU lock ensures the object won't be
1143 * released, tryget will fail if we lost the race.
1145 *sequence = atomic_read(&root->dead_count);
1146 if (iter->last_dead_count == *sequence) {
1148 position = iter->last_visited;
1151 * We cannot take a reference to root because we might race
1152 * with root removal and returning NULL would end up in
1153 * an endless loop on the iterator user level when root
1154 * would be returned all the time.
1156 if (position && position != root &&
1157 !css_tryget_online(&position->css))
1163 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter *iter,
1164 struct mem_cgroup *last_visited,
1165 struct mem_cgroup *new_position,
1166 struct mem_cgroup *root,
1169 /* root reference counting symmetric to mem_cgroup_iter_load */
1170 if (last_visited && last_visited != root)
1171 css_put(&last_visited->css);
1173 * We store the sequence count from the time @last_visited was
1174 * loaded successfully instead of rereading it here so that we
1175 * don't lose destruction events in between. We could have
1176 * raced with the destruction of @new_position after all.
1178 iter->last_visited = new_position;
1180 iter->last_dead_count = sequence;
1184 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1185 * @root: hierarchy root
1186 * @prev: previously returned memcg, NULL on first invocation
1187 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1189 * Returns references to children of the hierarchy below @root, or
1190 * @root itself, or %NULL after a full round-trip.
1192 * Caller must pass the return value in @prev on subsequent
1193 * invocations for reference counting, or use mem_cgroup_iter_break()
1194 * to cancel a hierarchy walk before the round-trip is complete.
1196 * Reclaimers can specify a zone and a priority level in @reclaim to
1197 * divide up the memcgs in the hierarchy among all concurrent
1198 * reclaimers operating on the same zone and priority.
1200 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1201 struct mem_cgroup *prev,
1202 struct mem_cgroup_reclaim_cookie *reclaim)
1204 struct mem_cgroup *memcg = NULL;
1205 struct mem_cgroup *last_visited = NULL;
1207 if (mem_cgroup_disabled())
1211 root = root_mem_cgroup;
1213 if (prev && !reclaim)
1214 last_visited = prev;
1216 if (!root->use_hierarchy && root != root_mem_cgroup) {
1224 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1225 int uninitialized_var(seq);
1228 struct mem_cgroup_per_zone *mz;
1230 mz = mem_cgroup_zone_zoneinfo(root, reclaim->zone);
1231 iter = &mz->reclaim_iter[reclaim->priority];
1232 if (prev && reclaim->generation != iter->generation) {
1233 iter->last_visited = NULL;
1237 last_visited = mem_cgroup_iter_load(iter, root, &seq);
1240 memcg = __mem_cgroup_iter_next(root, last_visited);
1243 mem_cgroup_iter_update(iter, last_visited, memcg, root,
1248 else if (!prev && memcg)
1249 reclaim->generation = iter->generation;
1258 if (prev && prev != root)
1259 css_put(&prev->css);
1265 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1266 * @root: hierarchy root
1267 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1269 void mem_cgroup_iter_break(struct mem_cgroup *root,
1270 struct mem_cgroup *prev)
1273 root = root_mem_cgroup;
1274 if (prev && prev != root)
1275 css_put(&prev->css);
1279 * Iteration constructs for visiting all cgroups (under a tree). If
1280 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1281 * be used for reference counting.
1283 #define for_each_mem_cgroup_tree(iter, root) \
1284 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1286 iter = mem_cgroup_iter(root, iter, NULL))
1288 #define for_each_mem_cgroup(iter) \
1289 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1291 iter = mem_cgroup_iter(NULL, iter, NULL))
1293 void __mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1295 struct mem_cgroup *memcg;
1298 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1299 if (unlikely(!memcg))
1304 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1307 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1315 EXPORT_SYMBOL(__mem_cgroup_count_vm_event);
1318 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1319 * @zone: zone of the wanted lruvec
1320 * @memcg: memcg of the wanted lruvec
1322 * Returns the lru list vector holding pages for the given @zone and
1323 * @mem. This can be the global zone lruvec, if the memory controller
1326 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1327 struct mem_cgroup *memcg)
1329 struct mem_cgroup_per_zone *mz;
1330 struct lruvec *lruvec;
1332 if (mem_cgroup_disabled()) {
1333 lruvec = &zone->lruvec;
1337 mz = mem_cgroup_zone_zoneinfo(memcg, zone);
1338 lruvec = &mz->lruvec;
1341 * Since a node can be onlined after the mem_cgroup was created,
1342 * we have to be prepared to initialize lruvec->zone here;
1343 * and if offlined then reonlined, we need to reinitialize it.
1345 if (unlikely(lruvec->zone != zone))
1346 lruvec->zone = zone;
1351 * Following LRU functions are allowed to be used without PCG_LOCK.
1352 * Operations are called by routine of global LRU independently from memcg.
1353 * What we have to take care of here is validness of pc->mem_cgroup.
1355 * Changes to pc->mem_cgroup happens when
1358 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1359 * It is added to LRU before charge.
1360 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1361 * When moving account, the page is not on LRU. It's isolated.
1365 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1367 * @zone: zone of the page
1369 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1371 struct mem_cgroup_per_zone *mz;
1372 struct mem_cgroup *memcg;
1373 struct page_cgroup *pc;
1374 struct lruvec *lruvec;
1376 if (mem_cgroup_disabled()) {
1377 lruvec = &zone->lruvec;
1381 pc = lookup_page_cgroup(page);
1382 memcg = pc->mem_cgroup;
1385 * Surreptitiously switch any uncharged offlist page to root:
1386 * an uncharged page off lru does nothing to secure
1387 * its former mem_cgroup from sudden removal.
1389 * Our caller holds lru_lock, and PageCgroupUsed is updated
1390 * under page_cgroup lock: between them, they make all uses
1391 * of pc->mem_cgroup safe.
1393 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1394 pc->mem_cgroup = memcg = root_mem_cgroup;
1396 mz = mem_cgroup_page_zoneinfo(memcg, page);
1397 lruvec = &mz->lruvec;
1400 * Since a node can be onlined after the mem_cgroup was created,
1401 * we have to be prepared to initialize lruvec->zone here;
1402 * and if offlined then reonlined, we need to reinitialize it.
1404 if (unlikely(lruvec->zone != zone))
1405 lruvec->zone = zone;
1410 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1411 * @lruvec: mem_cgroup per zone lru vector
1412 * @lru: index of lru list the page is sitting on
1413 * @nr_pages: positive when adding or negative when removing
1415 * This function must be called when a page is added to or removed from an
1418 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1421 struct mem_cgroup_per_zone *mz;
1422 unsigned long *lru_size;
1424 if (mem_cgroup_disabled())
1427 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1428 lru_size = mz->lru_size + lru;
1429 *lru_size += nr_pages;
1430 VM_BUG_ON((long)(*lru_size) < 0);
1434 * Checks whether given mem is same or in the root_mem_cgroup's
1437 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1438 struct mem_cgroup *memcg)
1440 if (root_memcg == memcg)
1442 if (!root_memcg->use_hierarchy || !memcg)
1444 return cgroup_is_descendant(memcg->css.cgroup, root_memcg->css.cgroup);
1447 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1448 struct mem_cgroup *memcg)
1453 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1458 bool task_in_mem_cgroup(struct task_struct *task,
1459 const struct mem_cgroup *memcg)
1461 struct mem_cgroup *curr = NULL;
1462 struct task_struct *p;
1465 p = find_lock_task_mm(task);
1467 curr = get_mem_cgroup_from_mm(p->mm);
1471 * All threads may have already detached their mm's, but the oom
1472 * killer still needs to detect if they have already been oom
1473 * killed to prevent needlessly killing additional tasks.
1476 curr = mem_cgroup_from_task(task);
1478 css_get(&curr->css);
1482 * We should check use_hierarchy of "memcg" not "curr". Because checking
1483 * use_hierarchy of "curr" here make this function true if hierarchy is
1484 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1485 * hierarchy(even if use_hierarchy is disabled in "memcg").
1487 ret = mem_cgroup_same_or_subtree(memcg, curr);
1488 css_put(&curr->css);
1492 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1494 unsigned long inactive_ratio;
1495 unsigned long inactive;
1496 unsigned long active;
1499 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1500 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1502 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1504 inactive_ratio = int_sqrt(10 * gb);
1508 return inactive * inactive_ratio < active;
1511 #define mem_cgroup_from_res_counter(counter, member) \
1512 container_of(counter, struct mem_cgroup, member)
1515 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1516 * @memcg: the memory cgroup
1518 * Returns the maximum amount of memory @mem can be charged with, in
1521 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1523 unsigned long long margin;
1525 margin = res_counter_margin(&memcg->res);
1526 if (do_swap_account)
1527 margin = min(margin, res_counter_margin(&memcg->memsw));
1528 return margin >> PAGE_SHIFT;
1531 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1534 if (mem_cgroup_disabled() || !memcg->css.parent)
1535 return vm_swappiness;
1537 return memcg->swappiness;
1541 * memcg->moving_account is used for checking possibility that some thread is
1542 * calling move_account(). When a thread on CPU-A starts moving pages under
1543 * a memcg, other threads should check memcg->moving_account under
1544 * rcu_read_lock(), like this:
1548 * memcg->moving_account+1 if (memcg->mocing_account)
1550 * synchronize_rcu() update something.
1555 /* for quick checking without looking up memcg */
1556 atomic_t memcg_moving __read_mostly;
1558 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1560 atomic_inc(&memcg_moving);
1561 atomic_inc(&memcg->moving_account);
1565 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1568 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1569 * We check NULL in callee rather than caller.
1572 atomic_dec(&memcg_moving);
1573 atomic_dec(&memcg->moving_account);
1578 * A routine for checking "mem" is under move_account() or not.
1580 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1581 * moving cgroups. This is for waiting at high-memory pressure
1584 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1586 struct mem_cgroup *from;
1587 struct mem_cgroup *to;
1590 * Unlike task_move routines, we access mc.to, mc.from not under
1591 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1593 spin_lock(&mc.lock);
1599 ret = mem_cgroup_same_or_subtree(memcg, from)
1600 || mem_cgroup_same_or_subtree(memcg, to);
1602 spin_unlock(&mc.lock);
1606 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1608 if (mc.moving_task && current != mc.moving_task) {
1609 if (mem_cgroup_under_move(memcg)) {
1611 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1612 /* moving charge context might have finished. */
1615 finish_wait(&mc.waitq, &wait);
1623 * Take this lock when
1624 * - a code tries to modify page's memcg while it's USED.
1625 * - a code tries to modify page state accounting in a memcg.
1627 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1628 unsigned long *flags)
1630 spin_lock_irqsave(&memcg->move_lock, *flags);
1633 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1634 unsigned long *flags)
1636 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1639 #define K(x) ((x) << (PAGE_SHIFT-10))
1641 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1642 * @memcg: The memory cgroup that went over limit
1643 * @p: Task that is going to be killed
1645 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1648 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1650 /* oom_info_lock ensures that parallel ooms do not interleave */
1651 static DEFINE_MUTEX(oom_info_lock);
1652 struct mem_cgroup *iter;
1658 mutex_lock(&oom_info_lock);
1661 pr_info("Task in ");
1662 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1663 pr_info(" killed as a result of limit of ");
1664 pr_cont_cgroup_path(memcg->css.cgroup);
1669 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1670 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1671 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1672 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1673 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1674 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1675 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1676 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1677 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1678 res_counter_read_u64(&memcg->kmem, RES_USAGE) >> 10,
1679 res_counter_read_u64(&memcg->kmem, RES_LIMIT) >> 10,
1680 res_counter_read_u64(&memcg->kmem, RES_FAILCNT));
1682 for_each_mem_cgroup_tree(iter, memcg) {
1683 pr_info("Memory cgroup stats for ");
1684 pr_cont_cgroup_path(iter->css.cgroup);
1687 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1688 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1690 pr_cont(" %s:%ldKB", mem_cgroup_stat_names[i],
1691 K(mem_cgroup_read_stat(iter, i)));
1694 for (i = 0; i < NR_LRU_LISTS; i++)
1695 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1696 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1700 mutex_unlock(&oom_info_lock);
1704 * This function returns the number of memcg under hierarchy tree. Returns
1705 * 1(self count) if no children.
1707 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1710 struct mem_cgroup *iter;
1712 for_each_mem_cgroup_tree(iter, memcg)
1718 * Return the memory (and swap, if configured) limit for a memcg.
1720 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1724 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1727 * Do not consider swap space if we cannot swap due to swappiness
1729 if (mem_cgroup_swappiness(memcg)) {
1732 limit += total_swap_pages << PAGE_SHIFT;
1733 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1736 * If memsw is finite and limits the amount of swap space
1737 * available to this memcg, return that limit.
1739 limit = min(limit, memsw);
1745 static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1748 struct mem_cgroup *iter;
1749 unsigned long chosen_points = 0;
1750 unsigned long totalpages;
1751 unsigned int points = 0;
1752 struct task_struct *chosen = NULL;
1755 * If current has a pending SIGKILL or is exiting, then automatically
1756 * select it. The goal is to allow it to allocate so that it may
1757 * quickly exit and free its memory.
1759 if (fatal_signal_pending(current) || current->flags & PF_EXITING) {
1760 set_thread_flag(TIF_MEMDIE);
1764 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1765 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1766 for_each_mem_cgroup_tree(iter, memcg) {
1767 struct css_task_iter it;
1768 struct task_struct *task;
1770 css_task_iter_start(&iter->css, &it);
1771 while ((task = css_task_iter_next(&it))) {
1772 switch (oom_scan_process_thread(task, totalpages, NULL,
1774 case OOM_SCAN_SELECT:
1776 put_task_struct(chosen);
1778 chosen_points = ULONG_MAX;
1779 get_task_struct(chosen);
1781 case OOM_SCAN_CONTINUE:
1783 case OOM_SCAN_ABORT:
1784 css_task_iter_end(&it);
1785 mem_cgroup_iter_break(memcg, iter);
1787 put_task_struct(chosen);
1792 points = oom_badness(task, memcg, NULL, totalpages);
1793 if (!points || points < chosen_points)
1795 /* Prefer thread group leaders for display purposes */
1796 if (points == chosen_points &&
1797 thread_group_leader(chosen))
1801 put_task_struct(chosen);
1803 chosen_points = points;
1804 get_task_struct(chosen);
1806 css_task_iter_end(&it);
1811 points = chosen_points * 1000 / totalpages;
1812 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1813 NULL, "Memory cgroup out of memory");
1816 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1818 unsigned long flags)
1820 unsigned long total = 0;
1821 bool noswap = false;
1824 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1826 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1829 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1831 drain_all_stock_async(memcg);
1832 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1834 * Allow limit shrinkers, which are triggered directly
1835 * by userspace, to catch signals and stop reclaim
1836 * after minimal progress, regardless of the margin.
1838 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1840 if (mem_cgroup_margin(memcg))
1843 * If nothing was reclaimed after two attempts, there
1844 * may be no reclaimable pages in this hierarchy.
1853 * test_mem_cgroup_node_reclaimable
1854 * @memcg: the target memcg
1855 * @nid: the node ID to be checked.
1856 * @noswap : specify true here if the user wants flle only information.
1858 * This function returns whether the specified memcg contains any
1859 * reclaimable pages on a node. Returns true if there are any reclaimable
1860 * pages in the node.
1862 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1863 int nid, bool noswap)
1865 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1867 if (noswap || !total_swap_pages)
1869 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1874 #if MAX_NUMNODES > 1
1877 * Always updating the nodemask is not very good - even if we have an empty
1878 * list or the wrong list here, we can start from some node and traverse all
1879 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1882 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1886 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1887 * pagein/pageout changes since the last update.
1889 if (!atomic_read(&memcg->numainfo_events))
1891 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1894 /* make a nodemask where this memcg uses memory from */
1895 memcg->scan_nodes = node_states[N_MEMORY];
1897 for_each_node_mask(nid, node_states[N_MEMORY]) {
1899 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1900 node_clear(nid, memcg->scan_nodes);
1903 atomic_set(&memcg->numainfo_events, 0);
1904 atomic_set(&memcg->numainfo_updating, 0);
1908 * Selecting a node where we start reclaim from. Because what we need is just
1909 * reducing usage counter, start from anywhere is O,K. Considering
1910 * memory reclaim from current node, there are pros. and cons.
1912 * Freeing memory from current node means freeing memory from a node which
1913 * we'll use or we've used. So, it may make LRU bad. And if several threads
1914 * hit limits, it will see a contention on a node. But freeing from remote
1915 * node means more costs for memory reclaim because of memory latency.
1917 * Now, we use round-robin. Better algorithm is welcomed.
1919 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1923 mem_cgroup_may_update_nodemask(memcg);
1924 node = memcg->last_scanned_node;
1926 node = next_node(node, memcg->scan_nodes);
1927 if (node == MAX_NUMNODES)
1928 node = first_node(memcg->scan_nodes);
1930 * We call this when we hit limit, not when pages are added to LRU.
1931 * No LRU may hold pages because all pages are UNEVICTABLE or
1932 * memcg is too small and all pages are not on LRU. In that case,
1933 * we use curret node.
1935 if (unlikely(node == MAX_NUMNODES))
1936 node = numa_node_id();
1938 memcg->last_scanned_node = node;
1943 * Check all nodes whether it contains reclaimable pages or not.
1944 * For quick scan, we make use of scan_nodes. This will allow us to skip
1945 * unused nodes. But scan_nodes is lazily updated and may not cotain
1946 * enough new information. We need to do double check.
1948 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1953 * quick check...making use of scan_node.
1954 * We can skip unused nodes.
1956 if (!nodes_empty(memcg->scan_nodes)) {
1957 for (nid = first_node(memcg->scan_nodes);
1959 nid = next_node(nid, memcg->scan_nodes)) {
1961 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1966 * Check rest of nodes.
1968 for_each_node_state(nid, N_MEMORY) {
1969 if (node_isset(nid, memcg->scan_nodes))
1971 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1978 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1983 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1985 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1989 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1992 unsigned long *total_scanned)
1994 struct mem_cgroup *victim = NULL;
1997 unsigned long excess;
1998 unsigned long nr_scanned;
1999 struct mem_cgroup_reclaim_cookie reclaim = {
2004 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
2007 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
2012 * If we have not been able to reclaim
2013 * anything, it might because there are
2014 * no reclaimable pages under this hierarchy
2019 * We want to do more targeted reclaim.
2020 * excess >> 2 is not to excessive so as to
2021 * reclaim too much, nor too less that we keep
2022 * coming back to reclaim from this cgroup
2024 if (total >= (excess >> 2) ||
2025 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
2030 if (!mem_cgroup_reclaimable(victim, false))
2032 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
2034 *total_scanned += nr_scanned;
2035 if (!res_counter_soft_limit_excess(&root_memcg->res))
2038 mem_cgroup_iter_break(root_memcg, victim);
2042 #ifdef CONFIG_LOCKDEP
2043 static struct lockdep_map memcg_oom_lock_dep_map = {
2044 .name = "memcg_oom_lock",
2048 static DEFINE_SPINLOCK(memcg_oom_lock);
2051 * Check OOM-Killer is already running under our hierarchy.
2052 * If someone is running, return false.
2054 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
2056 struct mem_cgroup *iter, *failed = NULL;
2058 spin_lock(&memcg_oom_lock);
2060 for_each_mem_cgroup_tree(iter, memcg) {
2061 if (iter->oom_lock) {
2063 * this subtree of our hierarchy is already locked
2064 * so we cannot give a lock.
2067 mem_cgroup_iter_break(memcg, iter);
2070 iter->oom_lock = true;
2075 * OK, we failed to lock the whole subtree so we have
2076 * to clean up what we set up to the failing subtree
2078 for_each_mem_cgroup_tree(iter, memcg) {
2079 if (iter == failed) {
2080 mem_cgroup_iter_break(memcg, iter);
2083 iter->oom_lock = false;
2086 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
2088 spin_unlock(&memcg_oom_lock);
2093 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
2095 struct mem_cgroup *iter;
2097 spin_lock(&memcg_oom_lock);
2098 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
2099 for_each_mem_cgroup_tree(iter, memcg)
2100 iter->oom_lock = false;
2101 spin_unlock(&memcg_oom_lock);
2104 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
2106 struct mem_cgroup *iter;
2108 for_each_mem_cgroup_tree(iter, memcg)
2109 atomic_inc(&iter->under_oom);
2112 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
2114 struct mem_cgroup *iter;
2117 * When a new child is created while the hierarchy is under oom,
2118 * mem_cgroup_oom_lock() may not be called. We have to use
2119 * atomic_add_unless() here.
2121 for_each_mem_cgroup_tree(iter, memcg)
2122 atomic_add_unless(&iter->under_oom, -1, 0);
2125 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
2127 struct oom_wait_info {
2128 struct mem_cgroup *memcg;
2132 static int memcg_oom_wake_function(wait_queue_t *wait,
2133 unsigned mode, int sync, void *arg)
2135 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
2136 struct mem_cgroup *oom_wait_memcg;
2137 struct oom_wait_info *oom_wait_info;
2139 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
2140 oom_wait_memcg = oom_wait_info->memcg;
2143 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2144 * Then we can use css_is_ancestor without taking care of RCU.
2146 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
2147 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
2149 return autoremove_wake_function(wait, mode, sync, arg);
2152 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
2154 atomic_inc(&memcg->oom_wakeups);
2155 /* for filtering, pass "memcg" as argument. */
2156 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
2159 static void memcg_oom_recover(struct mem_cgroup *memcg)
2161 if (memcg && atomic_read(&memcg->under_oom))
2162 memcg_wakeup_oom(memcg);
2165 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
2167 if (!current->memcg_oom.may_oom)
2170 * We are in the middle of the charge context here, so we
2171 * don't want to block when potentially sitting on a callstack
2172 * that holds all kinds of filesystem and mm locks.
2174 * Also, the caller may handle a failed allocation gracefully
2175 * (like optional page cache readahead) and so an OOM killer
2176 * invocation might not even be necessary.
2178 * That's why we don't do anything here except remember the
2179 * OOM context and then deal with it at the end of the page
2180 * fault when the stack is unwound, the locks are released,
2181 * and when we know whether the fault was overall successful.
2183 css_get(&memcg->css);
2184 current->memcg_oom.memcg = memcg;
2185 current->memcg_oom.gfp_mask = mask;
2186 current->memcg_oom.order = order;
2190 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2191 * @handle: actually kill/wait or just clean up the OOM state
2193 * This has to be called at the end of a page fault if the memcg OOM
2194 * handler was enabled.
2196 * Memcg supports userspace OOM handling where failed allocations must
2197 * sleep on a waitqueue until the userspace task resolves the
2198 * situation. Sleeping directly in the charge context with all kinds
2199 * of locks held is not a good idea, instead we remember an OOM state
2200 * in the task and mem_cgroup_oom_synchronize() has to be called at
2201 * the end of the page fault to complete the OOM handling.
2203 * Returns %true if an ongoing memcg OOM situation was detected and
2204 * completed, %false otherwise.
2206 bool mem_cgroup_oom_synchronize(bool handle)
2208 struct mem_cgroup *memcg = current->memcg_oom.memcg;
2209 struct oom_wait_info owait;
2212 /* OOM is global, do not handle */
2219 owait.memcg = memcg;
2220 owait.wait.flags = 0;
2221 owait.wait.func = memcg_oom_wake_function;
2222 owait.wait.private = current;
2223 INIT_LIST_HEAD(&owait.wait.task_list);
2225 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
2226 mem_cgroup_mark_under_oom(memcg);
2228 locked = mem_cgroup_oom_trylock(memcg);
2231 mem_cgroup_oom_notify(memcg);
2233 if (locked && !memcg->oom_kill_disable) {
2234 mem_cgroup_unmark_under_oom(memcg);
2235 finish_wait(&memcg_oom_waitq, &owait.wait);
2236 mem_cgroup_out_of_memory(memcg, current->memcg_oom.gfp_mask,
2237 current->memcg_oom.order);
2240 mem_cgroup_unmark_under_oom(memcg);
2241 finish_wait(&memcg_oom_waitq, &owait.wait);
2245 mem_cgroup_oom_unlock(memcg);
2247 * There is no guarantee that an OOM-lock contender
2248 * sees the wakeups triggered by the OOM kill
2249 * uncharges. Wake any sleepers explicitely.
2251 memcg_oom_recover(memcg);
2254 current->memcg_oom.memcg = NULL;
2255 css_put(&memcg->css);
2260 * Used to update mapped file or writeback or other statistics.
2262 * Notes: Race condition
2264 * We usually use lock_page_cgroup() for accessing page_cgroup member but
2265 * it tends to be costly. But considering some conditions, we doesn't need
2266 * to do so _always_.
2268 * Considering "charge", lock_page_cgroup() is not required because all
2269 * file-stat operations happen after a page is attached to radix-tree. There
2270 * are no race with "charge".
2272 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2273 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2274 * if there are race with "uncharge". Statistics itself is properly handled
2277 * Considering "move", this is an only case we see a race. To make the race
2278 * small, we check memcg->moving_account and detect there are possibility
2279 * of race or not. If there is, we take a lock.
2282 void __mem_cgroup_begin_update_page_stat(struct page *page,
2283 bool *locked, unsigned long *flags)
2285 struct mem_cgroup *memcg;
2286 struct page_cgroup *pc;
2288 pc = lookup_page_cgroup(page);
2290 memcg = pc->mem_cgroup;
2291 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2294 * If this memory cgroup is not under account moving, we don't
2295 * need to take move_lock_mem_cgroup(). Because we already hold
2296 * rcu_read_lock(), any calls to move_account will be delayed until
2297 * rcu_read_unlock().
2299 VM_BUG_ON(!rcu_read_lock_held());
2300 if (atomic_read(&memcg->moving_account) <= 0)
2303 move_lock_mem_cgroup(memcg, flags);
2304 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
2305 move_unlock_mem_cgroup(memcg, flags);
2311 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
2313 struct page_cgroup *pc = lookup_page_cgroup(page);
2316 * It's guaranteed that pc->mem_cgroup never changes while
2317 * lock is held because a routine modifies pc->mem_cgroup
2318 * should take move_lock_mem_cgroup().
2320 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
2323 void mem_cgroup_update_page_stat(struct page *page,
2324 enum mem_cgroup_stat_index idx, int val)
2326 struct mem_cgroup *memcg;
2327 struct page_cgroup *pc = lookup_page_cgroup(page);
2328 unsigned long uninitialized_var(flags);
2330 if (mem_cgroup_disabled())
2333 VM_BUG_ON(!rcu_read_lock_held());
2334 memcg = pc->mem_cgroup;
2335 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2338 this_cpu_add(memcg->stat->count[idx], val);
2342 * size of first charge trial. "32" comes from vmscan.c's magic value.
2343 * TODO: maybe necessary to use big numbers in big irons.
2345 #define CHARGE_BATCH 32U
2346 struct memcg_stock_pcp {
2347 struct mem_cgroup *cached; /* this never be root cgroup */
2348 unsigned int nr_pages;
2349 struct work_struct work;
2350 unsigned long flags;
2351 #define FLUSHING_CACHED_CHARGE 0
2353 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2354 static DEFINE_MUTEX(percpu_charge_mutex);
2357 * consume_stock: Try to consume stocked charge on this cpu.
2358 * @memcg: memcg to consume from.
2359 * @nr_pages: how many pages to charge.
2361 * The charges will only happen if @memcg matches the current cpu's memcg
2362 * stock, and at least @nr_pages are available in that stock. Failure to
2363 * service an allocation will refill the stock.
2365 * returns true if successful, false otherwise.
2367 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2369 struct memcg_stock_pcp *stock;
2372 if (nr_pages > CHARGE_BATCH)
2375 stock = &get_cpu_var(memcg_stock);
2376 if (memcg == stock->cached && stock->nr_pages >= nr_pages)
2377 stock->nr_pages -= nr_pages;
2378 else /* need to call res_counter_charge */
2380 put_cpu_var(memcg_stock);
2385 * Returns stocks cached in percpu to res_counter and reset cached information.
2387 static void drain_stock(struct memcg_stock_pcp *stock)
2389 struct mem_cgroup *old = stock->cached;
2391 if (stock->nr_pages) {
2392 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2394 res_counter_uncharge(&old->res, bytes);
2395 if (do_swap_account)
2396 res_counter_uncharge(&old->memsw, bytes);
2397 stock->nr_pages = 0;
2399 stock->cached = NULL;
2403 * This must be called under preempt disabled or must be called by
2404 * a thread which is pinned to local cpu.
2406 static void drain_local_stock(struct work_struct *dummy)
2408 struct memcg_stock_pcp *stock = this_cpu_ptr(&memcg_stock);
2410 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2413 static void __init memcg_stock_init(void)
2417 for_each_possible_cpu(cpu) {
2418 struct memcg_stock_pcp *stock =
2419 &per_cpu(memcg_stock, cpu);
2420 INIT_WORK(&stock->work, drain_local_stock);
2425 * Cache charges(val) which is from res_counter, to local per_cpu area.
2426 * This will be consumed by consume_stock() function, later.
2428 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2430 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2432 if (stock->cached != memcg) { /* reset if necessary */
2434 stock->cached = memcg;
2436 stock->nr_pages += nr_pages;
2437 put_cpu_var(memcg_stock);
2441 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2442 * of the hierarchy under it. sync flag says whether we should block
2443 * until the work is done.
2445 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2449 /* Notify other cpus that system-wide "drain" is running */
2452 for_each_online_cpu(cpu) {
2453 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2454 struct mem_cgroup *memcg;
2456 memcg = stock->cached;
2457 if (!memcg || !stock->nr_pages)
2459 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2461 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2463 drain_local_stock(&stock->work);
2465 schedule_work_on(cpu, &stock->work);
2473 for_each_online_cpu(cpu) {
2474 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2475 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2476 flush_work(&stock->work);
2483 * Tries to drain stocked charges in other cpus. This function is asynchronous
2484 * and just put a work per cpu for draining localy on each cpu. Caller can
2485 * expects some charges will be back to res_counter later but cannot wait for
2488 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2491 * If someone calls draining, avoid adding more kworker runs.
2493 if (!mutex_trylock(&percpu_charge_mutex))
2495 drain_all_stock(root_memcg, false);
2496 mutex_unlock(&percpu_charge_mutex);
2499 /* This is a synchronous drain interface. */
2500 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2502 /* called when force_empty is called */
2503 mutex_lock(&percpu_charge_mutex);
2504 drain_all_stock(root_memcg, true);
2505 mutex_unlock(&percpu_charge_mutex);
2509 * This function drains percpu counter value from DEAD cpu and
2510 * move it to local cpu. Note that this function can be preempted.
2512 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2516 spin_lock(&memcg->pcp_counter_lock);
2517 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2518 long x = per_cpu(memcg->stat->count[i], cpu);
2520 per_cpu(memcg->stat->count[i], cpu) = 0;
2521 memcg->nocpu_base.count[i] += x;
2523 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2524 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2526 per_cpu(memcg->stat->events[i], cpu) = 0;
2527 memcg->nocpu_base.events[i] += x;
2529 spin_unlock(&memcg->pcp_counter_lock);
2532 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
2533 unsigned long action,
2536 int cpu = (unsigned long)hcpu;
2537 struct memcg_stock_pcp *stock;
2538 struct mem_cgroup *iter;
2540 if (action == CPU_ONLINE)
2543 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2546 for_each_mem_cgroup(iter)
2547 mem_cgroup_drain_pcp_counter(iter, cpu);
2549 stock = &per_cpu(memcg_stock, cpu);
2555 * mem_cgroup_try_charge - try charging a memcg
2556 * @memcg: memcg to charge
2557 * @nr_pages: number of pages to charge
2559 * Returns 0 if @memcg was charged successfully, -EINTR if the charge
2560 * was bypassed to root_mem_cgroup, and -ENOMEM if the charge failed.
2562 static int mem_cgroup_try_charge(struct mem_cgroup *memcg,
2564 unsigned int nr_pages)
2566 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2567 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2568 struct mem_cgroup *mem_over_limit;
2569 struct res_counter *fail_res;
2570 unsigned long nr_reclaimed;
2571 unsigned long flags = 0;
2572 unsigned long long size;
2576 if (consume_stock(memcg, nr_pages))
2579 size = batch * PAGE_SIZE;
2580 if (!res_counter_charge(&memcg->res, size, &fail_res)) {
2581 if (!do_swap_account)
2583 if (!res_counter_charge(&memcg->memsw, size, &fail_res))
2585 res_counter_uncharge(&memcg->res, size);
2586 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2587 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2589 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2591 if (batch > nr_pages) {
2597 * Unlike in global OOM situations, memcg is not in a physical
2598 * memory shortage. Allow dying and OOM-killed tasks to
2599 * bypass the last charges so that they can exit quickly and
2600 * free their memory.
2602 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
2603 fatal_signal_pending(current) ||
2604 current->flags & PF_EXITING))
2607 if (unlikely(task_in_memcg_oom(current)))
2610 if (!(gfp_mask & __GFP_WAIT))
2613 nr_reclaimed = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2615 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2618 if (gfp_mask & __GFP_NORETRY)
2621 * Even though the limit is exceeded at this point, reclaim
2622 * may have been able to free some pages. Retry the charge
2623 * before killing the task.
2625 * Only for regular pages, though: huge pages are rather
2626 * unlikely to succeed so close to the limit, and we fall back
2627 * to regular pages anyway in case of failure.
2629 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2632 * At task move, charge accounts can be doubly counted. So, it's
2633 * better to wait until the end of task_move if something is going on.
2635 if (mem_cgroup_wait_acct_move(mem_over_limit))
2641 if (gfp_mask & __GFP_NOFAIL)
2644 if (fatal_signal_pending(current))
2647 mem_cgroup_oom(mem_over_limit, gfp_mask, get_order(nr_pages));
2649 if (!(gfp_mask & __GFP_NOFAIL))
2652 memcg = root_mem_cgroup;
2657 if (batch > nr_pages)
2658 refill_stock(memcg, batch - nr_pages);
2664 * mem_cgroup_try_charge_mm - try charging a mm
2665 * @mm: mm_struct to charge
2666 * @nr_pages: number of pages to charge
2667 * @oom: trigger OOM if reclaim fails
2669 * Returns the charged mem_cgroup associated with the given mm_struct or
2670 * NULL the charge failed.
2672 static struct mem_cgroup *mem_cgroup_try_charge_mm(struct mm_struct *mm,
2674 unsigned int nr_pages)
2677 struct mem_cgroup *memcg;
2680 memcg = get_mem_cgroup_from_mm(mm);
2681 ret = mem_cgroup_try_charge(memcg, gfp_mask, nr_pages);
2682 css_put(&memcg->css);
2684 memcg = root_mem_cgroup;
2692 * Somemtimes we have to undo a charge we got by try_charge().
2693 * This function is for that and do uncharge, put css's refcnt.
2694 * gotten by try_charge().
2696 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2697 unsigned int nr_pages)
2699 unsigned long bytes = nr_pages * PAGE_SIZE;
2701 res_counter_uncharge(&memcg->res, bytes);
2702 if (do_swap_account)
2703 res_counter_uncharge(&memcg->memsw, bytes);
2707 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2708 * This is useful when moving usage to parent cgroup.
2710 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2711 unsigned int nr_pages)
2713 unsigned long bytes = nr_pages * PAGE_SIZE;
2715 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2716 if (do_swap_account)
2717 res_counter_uncharge_until(&memcg->memsw,
2718 memcg->memsw.parent, bytes);
2722 * A helper function to get mem_cgroup from ID. must be called under
2723 * rcu_read_lock(). The caller is responsible for calling
2724 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2725 * refcnt from swap can be called against removed memcg.)
2727 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2729 /* ID 0 is unused ID */
2732 return mem_cgroup_from_id(id);
2735 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2737 struct mem_cgroup *memcg = NULL;
2738 struct page_cgroup *pc;
2742 VM_BUG_ON_PAGE(!PageLocked(page), page);
2744 pc = lookup_page_cgroup(page);
2745 lock_page_cgroup(pc);
2746 if (PageCgroupUsed(pc)) {
2747 memcg = pc->mem_cgroup;
2748 if (memcg && !css_tryget_online(&memcg->css))
2750 } else if (PageSwapCache(page)) {
2751 ent.val = page_private(page);
2752 id = lookup_swap_cgroup_id(ent);
2754 memcg = mem_cgroup_lookup(id);
2755 if (memcg && !css_tryget_online(&memcg->css))
2759 unlock_page_cgroup(pc);
2763 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2765 unsigned int nr_pages,
2766 enum charge_type ctype,
2769 struct page_cgroup *pc = lookup_page_cgroup(page);
2770 struct zone *uninitialized_var(zone);
2771 struct lruvec *lruvec;
2772 bool was_on_lru = false;
2775 lock_page_cgroup(pc);
2776 VM_BUG_ON_PAGE(PageCgroupUsed(pc), page);
2778 * we don't need page_cgroup_lock about tail pages, becase they are not
2779 * accessed by any other context at this point.
2783 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2784 * may already be on some other mem_cgroup's LRU. Take care of it.
2787 zone = page_zone(page);
2788 spin_lock_irq(&zone->lru_lock);
2789 if (PageLRU(page)) {
2790 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2792 del_page_from_lru_list(page, lruvec, page_lru(page));
2797 pc->mem_cgroup = memcg;
2798 SetPageCgroupUsed(pc);
2802 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2803 VM_BUG_ON_PAGE(PageLRU(page), page);
2805 add_page_to_lru_list(page, lruvec, page_lru(page));
2807 spin_unlock_irq(&zone->lru_lock);
2810 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2815 mem_cgroup_charge_statistics(memcg, page, anon, nr_pages);
2816 unlock_page_cgroup(pc);
2819 * "charge_statistics" updated event counter. Then, check it.
2820 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2821 * if they exceeds softlimit.
2823 memcg_check_events(memcg, page);
2826 static DEFINE_MUTEX(set_limit_mutex);
2828 #ifdef CONFIG_MEMCG_KMEM
2830 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2831 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2833 static DEFINE_MUTEX(memcg_slab_mutex);
2835 static DEFINE_MUTEX(activate_kmem_mutex);
2837 static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
2839 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg) &&
2840 memcg_kmem_is_active(memcg);
2844 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2845 * in the memcg_cache_params struct.
2847 static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p)
2849 struct kmem_cache *cachep;
2851 VM_BUG_ON(p->is_root_cache);
2852 cachep = p->root_cache;
2853 return cache_from_memcg_idx(cachep, memcg_cache_id(p->memcg));
2856 #ifdef CONFIG_SLABINFO
2857 static int mem_cgroup_slabinfo_read(struct seq_file *m, void *v)
2859 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
2860 struct memcg_cache_params *params;
2862 if (!memcg_can_account_kmem(memcg))
2865 print_slabinfo_header(m);
2867 mutex_lock(&memcg_slab_mutex);
2868 list_for_each_entry(params, &memcg->memcg_slab_caches, list)
2869 cache_show(memcg_params_to_cache(params), m);
2870 mutex_unlock(&memcg_slab_mutex);
2876 static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size)
2878 struct res_counter *fail_res;
2881 ret = res_counter_charge(&memcg->kmem, size, &fail_res);
2885 ret = mem_cgroup_try_charge(memcg, gfp, size >> PAGE_SHIFT);
2886 if (ret == -EINTR) {
2888 * mem_cgroup_try_charge() chosed to bypass to root due to
2889 * OOM kill or fatal signal. Since our only options are to
2890 * either fail the allocation or charge it to this cgroup, do
2891 * it as a temporary condition. But we can't fail. From a
2892 * kmem/slab perspective, the cache has already been selected,
2893 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2896 * This condition will only trigger if the task entered
2897 * memcg_charge_kmem in a sane state, but was OOM-killed during
2898 * mem_cgroup_try_charge() above. Tasks that were already
2899 * dying when the allocation triggers should have been already
2900 * directed to the root cgroup in memcontrol.h
2902 res_counter_charge_nofail(&memcg->res, size, &fail_res);
2903 if (do_swap_account)
2904 res_counter_charge_nofail(&memcg->memsw, size,
2908 res_counter_uncharge(&memcg->kmem, size);
2913 static void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size)
2915 res_counter_uncharge(&memcg->res, size);
2916 if (do_swap_account)
2917 res_counter_uncharge(&memcg->memsw, size);
2920 if (res_counter_uncharge(&memcg->kmem, size))
2924 * Releases a reference taken in kmem_cgroup_css_offline in case
2925 * this last uncharge is racing with the offlining code or it is
2926 * outliving the memcg existence.
2928 * The memory barrier imposed by test&clear is paired with the
2929 * explicit one in memcg_kmem_mark_dead().
2931 if (memcg_kmem_test_and_clear_dead(memcg))
2932 css_put(&memcg->css);
2936 * helper for acessing a memcg's index. It will be used as an index in the
2937 * child cache array in kmem_cache, and also to derive its name. This function
2938 * will return -1 when this is not a kmem-limited memcg.
2940 int memcg_cache_id(struct mem_cgroup *memcg)
2942 return memcg ? memcg->kmemcg_id : -1;
2945 static size_t memcg_caches_array_size(int num_groups)
2948 if (num_groups <= 0)
2951 size = 2 * num_groups;
2952 if (size < MEMCG_CACHES_MIN_SIZE)
2953 size = MEMCG_CACHES_MIN_SIZE;
2954 else if (size > MEMCG_CACHES_MAX_SIZE)
2955 size = MEMCG_CACHES_MAX_SIZE;
2961 * We should update the current array size iff all caches updates succeed. This
2962 * can only be done from the slab side. The slab mutex needs to be held when
2965 void memcg_update_array_size(int num)
2967 if (num > memcg_limited_groups_array_size)
2968 memcg_limited_groups_array_size = memcg_caches_array_size(num);
2971 int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
2973 struct memcg_cache_params *cur_params = s->memcg_params;
2975 VM_BUG_ON(!is_root_cache(s));
2977 if (num_groups > memcg_limited_groups_array_size) {
2979 struct memcg_cache_params *new_params;
2980 ssize_t size = memcg_caches_array_size(num_groups);
2982 size *= sizeof(void *);
2983 size += offsetof(struct memcg_cache_params, memcg_caches);
2985 new_params = kzalloc(size, GFP_KERNEL);
2989 new_params->is_root_cache = true;
2992 * There is the chance it will be bigger than
2993 * memcg_limited_groups_array_size, if we failed an allocation
2994 * in a cache, in which case all caches updated before it, will
2995 * have a bigger array.
2997 * But if that is the case, the data after
2998 * memcg_limited_groups_array_size is certainly unused
3000 for (i = 0; i < memcg_limited_groups_array_size; i++) {
3001 if (!cur_params->memcg_caches[i])
3003 new_params->memcg_caches[i] =
3004 cur_params->memcg_caches[i];
3008 * Ideally, we would wait until all caches succeed, and only
3009 * then free the old one. But this is not worth the extra
3010 * pointer per-cache we'd have to have for this.
3012 * It is not a big deal if some caches are left with a size
3013 * bigger than the others. And all updates will reset this
3016 rcu_assign_pointer(s->memcg_params, new_params);
3018 kfree_rcu(cur_params, rcu_head);
3023 int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s,
3024 struct kmem_cache *root_cache)
3028 if (!memcg_kmem_enabled())
3032 size = offsetof(struct memcg_cache_params, memcg_caches);
3033 size += memcg_limited_groups_array_size * sizeof(void *);
3035 size = sizeof(struct memcg_cache_params);
3037 s->memcg_params = kzalloc(size, GFP_KERNEL);
3038 if (!s->memcg_params)
3042 s->memcg_params->memcg = memcg;
3043 s->memcg_params->root_cache = root_cache;
3044 css_get(&memcg->css);
3046 s->memcg_params->is_root_cache = true;
3051 void memcg_free_cache_params(struct kmem_cache *s)
3053 if (!s->memcg_params)
3055 if (!s->memcg_params->is_root_cache)
3056 css_put(&s->memcg_params->memcg->css);
3057 kfree(s->memcg_params);
3060 static void memcg_register_cache(struct mem_cgroup *memcg,
3061 struct kmem_cache *root_cache)
3063 static char memcg_name_buf[NAME_MAX + 1]; /* protected by
3065 struct kmem_cache *cachep;
3068 lockdep_assert_held(&memcg_slab_mutex);
3070 id = memcg_cache_id(memcg);
3073 * Since per-memcg caches are created asynchronously on first
3074 * allocation (see memcg_kmem_get_cache()), several threads can try to
3075 * create the same cache, but only one of them may succeed.
3077 if (cache_from_memcg_idx(root_cache, id))
3080 cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
3081 cachep = memcg_create_kmem_cache(memcg, root_cache, memcg_name_buf);
3083 * If we could not create a memcg cache, do not complain, because
3084 * that's not critical at all as we can always proceed with the root
3090 list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches);
3093 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3094 * barrier here to ensure nobody will see the kmem_cache partially
3099 BUG_ON(root_cache->memcg_params->memcg_caches[id]);
3100 root_cache->memcg_params->memcg_caches[id] = cachep;
3103 static void memcg_unregister_cache(struct kmem_cache *cachep)
3105 struct kmem_cache *root_cache;
3106 struct mem_cgroup *memcg;
3109 lockdep_assert_held(&memcg_slab_mutex);
3111 BUG_ON(is_root_cache(cachep));
3113 root_cache = cachep->memcg_params->root_cache;
3114 memcg = cachep->memcg_params->memcg;
3115 id = memcg_cache_id(memcg);
3117 BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
3118 root_cache->memcg_params->memcg_caches[id] = NULL;
3120 list_del(&cachep->memcg_params->list);
3122 kmem_cache_destroy(cachep);
3126 * During the creation a new cache, we need to disable our accounting mechanism
3127 * altogether. This is true even if we are not creating, but rather just
3128 * enqueing new caches to be created.
3130 * This is because that process will trigger allocations; some visible, like
3131 * explicit kmallocs to auxiliary data structures, name strings and internal
3132 * cache structures; some well concealed, like INIT_WORK() that can allocate
3133 * objects during debug.
3135 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3136 * to it. This may not be a bounded recursion: since the first cache creation
3137 * failed to complete (waiting on the allocation), we'll just try to create the
3138 * cache again, failing at the same point.
3140 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3141 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3142 * inside the following two functions.
3144 static inline void memcg_stop_kmem_account(void)
3146 VM_BUG_ON(!current->mm);
3147 current->memcg_kmem_skip_account++;
3150 static inline void memcg_resume_kmem_account(void)
3152 VM_BUG_ON(!current->mm);
3153 current->memcg_kmem_skip_account--;
3156 int __memcg_cleanup_cache_params(struct kmem_cache *s)
3158 struct kmem_cache *c;
3161 mutex_lock(&memcg_slab_mutex);
3162 for_each_memcg_cache_index(i) {
3163 c = cache_from_memcg_idx(s, i);
3167 memcg_unregister_cache(c);
3169 if (cache_from_memcg_idx(s, i))
3172 mutex_unlock(&memcg_slab_mutex);
3176 static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
3178 struct kmem_cache *cachep;
3179 struct memcg_cache_params *params, *tmp;
3181 if (!memcg_kmem_is_active(memcg))
3184 mutex_lock(&memcg_slab_mutex);
3185 list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
3186 cachep = memcg_params_to_cache(params);
3187 kmem_cache_shrink(cachep);
3188 if (atomic_read(&cachep->memcg_params->nr_pages) == 0)
3189 memcg_unregister_cache(cachep);
3191 mutex_unlock(&memcg_slab_mutex);
3194 struct memcg_register_cache_work {
3195 struct mem_cgroup *memcg;
3196 struct kmem_cache *cachep;
3197 struct work_struct work;
3200 static void memcg_register_cache_func(struct work_struct *w)
3202 struct memcg_register_cache_work *cw =
3203 container_of(w, struct memcg_register_cache_work, work);
3204 struct mem_cgroup *memcg = cw->memcg;
3205 struct kmem_cache *cachep = cw->cachep;
3207 mutex_lock(&memcg_slab_mutex);
3208 memcg_register_cache(memcg, cachep);
3209 mutex_unlock(&memcg_slab_mutex);
3211 css_put(&memcg->css);
3216 * Enqueue the creation of a per-memcg kmem_cache.
3218 static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
3219 struct kmem_cache *cachep)
3221 struct memcg_register_cache_work *cw;
3223 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
3225 css_put(&memcg->css);
3230 cw->cachep = cachep;
3232 INIT_WORK(&cw->work, memcg_register_cache_func);
3233 schedule_work(&cw->work);
3236 static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
3237 struct kmem_cache *cachep)
3240 * We need to stop accounting when we kmalloc, because if the
3241 * corresponding kmalloc cache is not yet created, the first allocation
3242 * in __memcg_schedule_register_cache will recurse.
3244 * However, it is better to enclose the whole function. Depending on
3245 * the debugging options enabled, INIT_WORK(), for instance, can
3246 * trigger an allocation. This too, will make us recurse. Because at
3247 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3248 * the safest choice is to do it like this, wrapping the whole function.
3250 memcg_stop_kmem_account();
3251 __memcg_schedule_register_cache(memcg, cachep);
3252 memcg_resume_kmem_account();
3255 int __memcg_charge_slab(struct kmem_cache *cachep, gfp_t gfp, int order)
3259 res = memcg_charge_kmem(cachep->memcg_params->memcg, gfp,
3260 PAGE_SIZE << order);
3262 atomic_add(1 << order, &cachep->memcg_params->nr_pages);
3266 void __memcg_uncharge_slab(struct kmem_cache *cachep, int order)
3268 memcg_uncharge_kmem(cachep->memcg_params->memcg, PAGE_SIZE << order);
3269 atomic_sub(1 << order, &cachep->memcg_params->nr_pages);
3273 * Return the kmem_cache we're supposed to use for a slab allocation.
3274 * We try to use the current memcg's version of the cache.
3276 * If the cache does not exist yet, if we are the first user of it,
3277 * we either create it immediately, if possible, or create it asynchronously
3279 * In the latter case, we will let the current allocation go through with
3280 * the original cache.
3282 * Can't be called in interrupt context or from kernel threads.
3283 * This function needs to be called with rcu_read_lock() held.
3285 struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
3288 struct mem_cgroup *memcg;
3289 struct kmem_cache *memcg_cachep;
3291 VM_BUG_ON(!cachep->memcg_params);
3292 VM_BUG_ON(!cachep->memcg_params->is_root_cache);
3294 if (!current->mm || current->memcg_kmem_skip_account)
3298 memcg = mem_cgroup_from_task(rcu_dereference(current->mm->owner));
3300 if (!memcg_can_account_kmem(memcg))
3303 memcg_cachep = cache_from_memcg_idx(cachep, memcg_cache_id(memcg));
3304 if (likely(memcg_cachep)) {
3305 cachep = memcg_cachep;
3309 /* The corresponding put will be done in the workqueue. */
3310 if (!css_tryget_online(&memcg->css))
3315 * If we are in a safe context (can wait, and not in interrupt
3316 * context), we could be be predictable and return right away.
3317 * This would guarantee that the allocation being performed
3318 * already belongs in the new cache.
3320 * However, there are some clashes that can arrive from locking.
3321 * For instance, because we acquire the slab_mutex while doing
3322 * memcg_create_kmem_cache, this means no further allocation
3323 * could happen with the slab_mutex held. So it's better to
3326 memcg_schedule_register_cache(memcg, cachep);
3334 * We need to verify if the allocation against current->mm->owner's memcg is
3335 * possible for the given order. But the page is not allocated yet, so we'll
3336 * need a further commit step to do the final arrangements.
3338 * It is possible for the task to switch cgroups in this mean time, so at
3339 * commit time, we can't rely on task conversion any longer. We'll then use
3340 * the handle argument to return to the caller which cgroup we should commit
3341 * against. We could also return the memcg directly and avoid the pointer
3342 * passing, but a boolean return value gives better semantics considering
3343 * the compiled-out case as well.
3345 * Returning true means the allocation is possible.
3348 __memcg_kmem_newpage_charge(gfp_t gfp, struct mem_cgroup **_memcg, int order)
3350 struct mem_cgroup *memcg;
3356 * Disabling accounting is only relevant for some specific memcg
3357 * internal allocations. Therefore we would initially not have such
3358 * check here, since direct calls to the page allocator that are
3359 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
3360 * outside memcg core. We are mostly concerned with cache allocations,
3361 * and by having this test at memcg_kmem_get_cache, we are already able
3362 * to relay the allocation to the root cache and bypass the memcg cache
3365 * There is one exception, though: the SLUB allocator does not create
3366 * large order caches, but rather service large kmallocs directly from
3367 * the page allocator. Therefore, the following sequence when backed by
3368 * the SLUB allocator:
3370 * memcg_stop_kmem_account();
3371 * kmalloc(<large_number>)
3372 * memcg_resume_kmem_account();
3374 * would effectively ignore the fact that we should skip accounting,
3375 * since it will drive us directly to this function without passing
3376 * through the cache selector memcg_kmem_get_cache. Such large
3377 * allocations are extremely rare but can happen, for instance, for the
3378 * cache arrays. We bring this test here.
3380 if (!current->mm || current->memcg_kmem_skip_account)
3383 memcg = get_mem_cgroup_from_mm(current->mm);
3385 if (!memcg_can_account_kmem(memcg)) {
3386 css_put(&memcg->css);
3390 ret = memcg_charge_kmem(memcg, gfp, PAGE_SIZE << order);
3394 css_put(&memcg->css);
3398 void __memcg_kmem_commit_charge(struct page *page, struct mem_cgroup *memcg,
3401 struct page_cgroup *pc;
3403 VM_BUG_ON(mem_cgroup_is_root(memcg));
3405 /* The page allocation failed. Revert */
3407 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3411 * The page is freshly allocated and not visible to any
3412 * outside callers yet. Set up pc non-atomically.
3414 pc = lookup_page_cgroup(page);
3415 pc->mem_cgroup = memcg;
3416 pc->flags = PCG_USED;
3419 void __memcg_kmem_uncharge_pages(struct page *page, int order)
3421 struct mem_cgroup *memcg = NULL;
3422 struct page_cgroup *pc;
3425 pc = lookup_page_cgroup(page);
3426 if (!PageCgroupUsed(pc))
3429 memcg = pc->mem_cgroup;
3433 * We trust that only if there is a memcg associated with the page, it
3434 * is a valid allocation
3439 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
3440 memcg_uncharge_kmem(memcg, PAGE_SIZE << order);
3443 static inline void memcg_unregister_all_caches(struct mem_cgroup *memcg)
3446 #endif /* CONFIG_MEMCG_KMEM */
3448 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3450 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3452 * Because tail pages are not marked as "used", set it. We're under
3453 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3454 * charge/uncharge will be never happen and move_account() is done under
3455 * compound_lock(), so we don't have to take care of races.
3457 void mem_cgroup_split_huge_fixup(struct page *head)
3459 struct page_cgroup *head_pc = lookup_page_cgroup(head);
3460 struct page_cgroup *pc;
3461 struct mem_cgroup *memcg;
3464 if (mem_cgroup_disabled())
3467 memcg = head_pc->mem_cgroup;
3468 for (i = 1; i < HPAGE_PMD_NR; i++) {
3470 pc->mem_cgroup = memcg;
3471 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
3473 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
3476 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3479 * mem_cgroup_move_account - move account of the page
3481 * @nr_pages: number of regular pages (>1 for huge pages)
3482 * @pc: page_cgroup of the page.
3483 * @from: mem_cgroup which the page is moved from.
3484 * @to: mem_cgroup which the page is moved to. @from != @to.
3486 * The caller must confirm following.
3487 * - page is not on LRU (isolate_page() is useful.)
3488 * - compound_lock is held when nr_pages > 1
3490 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3493 static int mem_cgroup_move_account(struct page *page,
3494 unsigned int nr_pages,
3495 struct page_cgroup *pc,
3496 struct mem_cgroup *from,
3497 struct mem_cgroup *to)
3499 unsigned long flags;
3501 bool anon = PageAnon(page);
3503 VM_BUG_ON(from == to);
3504 VM_BUG_ON_PAGE(PageLRU(page), page);
3506 * The page is isolated from LRU. So, collapse function
3507 * will not handle this page. But page splitting can happen.
3508 * Do this check under compound_page_lock(). The caller should
3512 if (nr_pages > 1 && !PageTransHuge(page))
3515 lock_page_cgroup(pc);
3518 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
3521 move_lock_mem_cgroup(from, &flags);
3523 if (!anon && page_mapped(page)) {
3524 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3526 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
3530 if (PageWriteback(page)) {
3531 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3533 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
3537 mem_cgroup_charge_statistics(from, page, anon, -nr_pages);
3539 /* caller should have done css_get */
3540 pc->mem_cgroup = to;
3541 mem_cgroup_charge_statistics(to, page, anon, nr_pages);
3542 move_unlock_mem_cgroup(from, &flags);
3545 unlock_page_cgroup(pc);
3549 memcg_check_events(to, page);
3550 memcg_check_events(from, page);
3556 * mem_cgroup_move_parent - moves page to the parent group
3557 * @page: the page to move
3558 * @pc: page_cgroup of the page
3559 * @child: page's cgroup
3561 * move charges to its parent or the root cgroup if the group has no
3562 * parent (aka use_hierarchy==0).
3563 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3564 * mem_cgroup_move_account fails) the failure is always temporary and
3565 * it signals a race with a page removal/uncharge or migration. In the
3566 * first case the page is on the way out and it will vanish from the LRU
3567 * on the next attempt and the call should be retried later.
3568 * Isolation from the LRU fails only if page has been isolated from
3569 * the LRU since we looked at it and that usually means either global
3570 * reclaim or migration going on. The page will either get back to the
3572 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3573 * (!PageCgroupUsed) or moved to a different group. The page will
3574 * disappear in the next attempt.
3576 static int mem_cgroup_move_parent(struct page *page,
3577 struct page_cgroup *pc,
3578 struct mem_cgroup *child)
3580 struct mem_cgroup *parent;
3581 unsigned int nr_pages;
3582 unsigned long uninitialized_var(flags);
3585 VM_BUG_ON(mem_cgroup_is_root(child));
3588 if (!get_page_unless_zero(page))
3590 if (isolate_lru_page(page))
3593 nr_pages = hpage_nr_pages(page);
3595 parent = parent_mem_cgroup(child);
3597 * If no parent, move charges to root cgroup.
3600 parent = root_mem_cgroup;
3603 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3604 flags = compound_lock_irqsave(page);
3607 ret = mem_cgroup_move_account(page, nr_pages,
3610 __mem_cgroup_cancel_local_charge(child, nr_pages);
3613 compound_unlock_irqrestore(page, flags);
3614 putback_lru_page(page);
3621 int mem_cgroup_charge_anon(struct page *page,
3622 struct mm_struct *mm, gfp_t gfp_mask)
3624 unsigned int nr_pages = 1;
3625 struct mem_cgroup *memcg;
3627 if (mem_cgroup_disabled())
3630 VM_BUG_ON_PAGE(page_mapped(page), page);
3631 VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
3634 if (PageTransHuge(page)) {
3635 nr_pages <<= compound_order(page);
3636 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3639 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, nr_pages);
3642 __mem_cgroup_commit_charge(memcg, page, nr_pages,
3643 MEM_CGROUP_CHARGE_TYPE_ANON, false);
3648 * While swap-in, try_charge -> commit or cancel, the page is locked.
3649 * And when try_charge() successfully returns, one refcnt to memcg without
3650 * struct page_cgroup is acquired. This refcnt will be consumed by
3651 * "commit()" or removed by "cancel()"
3653 static int __mem_cgroup_try_charge_swapin(struct mm_struct *mm,
3656 struct mem_cgroup **memcgp)
3658 struct mem_cgroup *memcg = NULL;
3659 struct page_cgroup *pc;
3662 pc = lookup_page_cgroup(page);
3664 * Every swap fault against a single page tries to charge the
3665 * page, bail as early as possible. shmem_unuse() encounters
3666 * already charged pages, too. The USED bit is protected by
3667 * the page lock, which serializes swap cache removal, which
3668 * in turn serializes uncharging.
3670 if (PageCgroupUsed(pc))
3672 if (do_swap_account)
3673 memcg = try_get_mem_cgroup_from_page(page);
3675 memcg = get_mem_cgroup_from_mm(mm);
3676 ret = mem_cgroup_try_charge(memcg, mask, 1);
3677 css_put(&memcg->css);
3679 memcg = root_mem_cgroup;
3687 int mem_cgroup_try_charge_swapin(struct mm_struct *mm, struct page *page,
3688 gfp_t gfp_mask, struct mem_cgroup **memcgp)
3690 if (mem_cgroup_disabled()) {
3695 * A racing thread's fault, or swapoff, may have already
3696 * updated the pte, and even removed page from swap cache: in
3697 * those cases unuse_pte()'s pte_same() test will fail; but
3698 * there's also a KSM case which does need to charge the page.
3700 if (!PageSwapCache(page)) {
3701 struct mem_cgroup *memcg;
3703 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1);
3709 return __mem_cgroup_try_charge_swapin(mm, page, gfp_mask, memcgp);
3712 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
3714 if (mem_cgroup_disabled())
3718 __mem_cgroup_cancel_charge(memcg, 1);
3722 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
3723 enum charge_type ctype)
3725 if (mem_cgroup_disabled())
3730 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
3732 * Now swap is on-memory. This means this page may be
3733 * counted both as mem and swap....double count.
3734 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3735 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3736 * may call delete_from_swap_cache() before reach here.
3738 if (do_swap_account && PageSwapCache(page)) {
3739 swp_entry_t ent = {.val = page_private(page)};
3740 mem_cgroup_uncharge_swap(ent);
3744 void mem_cgroup_commit_charge_swapin(struct page *page,
3745 struct mem_cgroup *memcg)
3747 __mem_cgroup_commit_charge_swapin(page, memcg,
3748 MEM_CGROUP_CHARGE_TYPE_ANON);
3751 int mem_cgroup_charge_file(struct page *page, struct mm_struct *mm,
3754 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3755 struct mem_cgroup *memcg;
3758 if (mem_cgroup_disabled())
3760 if (PageCompound(page))
3763 if (PageSwapCache(page)) { /* shmem */
3764 ret = __mem_cgroup_try_charge_swapin(mm, page,
3768 __mem_cgroup_commit_charge_swapin(page, memcg, type);
3772 memcg = mem_cgroup_try_charge_mm(mm, gfp_mask, 1);
3775 __mem_cgroup_commit_charge(memcg, page, 1, type, false);
3779 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
3780 unsigned int nr_pages,
3781 const enum charge_type ctype)
3783 struct memcg_batch_info *batch = NULL;
3784 bool uncharge_memsw = true;
3786 /* If swapout, usage of swap doesn't decrease */
3787 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
3788 uncharge_memsw = false;
3790 batch = ¤t->memcg_batch;
3792 * In usual, we do css_get() when we remember memcg pointer.
3793 * But in this case, we keep res->usage until end of a series of
3794 * uncharges. Then, it's ok to ignore memcg's refcnt.
3797 batch->memcg = memcg;
3799 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3800 * In those cases, all pages freed continuously can be expected to be in
3801 * the same cgroup and we have chance to coalesce uncharges.
3802 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3803 * because we want to do uncharge as soon as possible.
3806 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
3807 goto direct_uncharge;
3810 goto direct_uncharge;
3813 * In typical case, batch->memcg == mem. This means we can
3814 * merge a series of uncharges to an uncharge of res_counter.
3815 * If not, we uncharge res_counter ony by one.
3817 if (batch->memcg != memcg)
3818 goto direct_uncharge;
3819 /* remember freed charge and uncharge it later */
3822 batch->memsw_nr_pages++;
3825 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
3827 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
3828 if (unlikely(batch->memcg != memcg))
3829 memcg_oom_recover(memcg);
3833 * uncharge if !page_mapped(page)
3835 static struct mem_cgroup *
3836 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
3839 struct mem_cgroup *memcg = NULL;
3840 unsigned int nr_pages = 1;
3841 struct page_cgroup *pc;
3844 if (mem_cgroup_disabled())
3847 if (PageTransHuge(page)) {
3848 nr_pages <<= compound_order(page);
3849 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
3852 * Check if our page_cgroup is valid
3854 pc = lookup_page_cgroup(page);
3855 if (unlikely(!PageCgroupUsed(pc)))
3858 lock_page_cgroup(pc);
3860 memcg = pc->mem_cgroup;
3862 if (!PageCgroupUsed(pc))
3865 anon = PageAnon(page);
3868 case MEM_CGROUP_CHARGE_TYPE_ANON:
3870 * Generally PageAnon tells if it's the anon statistics to be
3871 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3872 * used before page reached the stage of being marked PageAnon.
3876 case MEM_CGROUP_CHARGE_TYPE_DROP:
3877 /* See mem_cgroup_prepare_migration() */
3878 if (page_mapped(page))
3881 * Pages under migration may not be uncharged. But
3882 * end_migration() /must/ be the one uncharging the
3883 * unused post-migration page and so it has to call
3884 * here with the migration bit still set. See the
3885 * res_counter handling below.
3887 if (!end_migration && PageCgroupMigration(pc))
3890 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3891 if (!PageAnon(page)) { /* Shared memory */
3892 if (page->mapping && !page_is_file_cache(page))
3894 } else if (page_mapped(page)) /* Anon */
3901 mem_cgroup_charge_statistics(memcg, page, anon, -nr_pages);
3903 ClearPageCgroupUsed(pc);
3905 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3906 * freed from LRU. This is safe because uncharged page is expected not
3907 * to be reused (freed soon). Exception is SwapCache, it's handled by
3908 * special functions.
3911 unlock_page_cgroup(pc);
3913 * even after unlock, we have memcg->res.usage here and this memcg
3914 * will never be freed, so it's safe to call css_get().
3916 memcg_check_events(memcg, page);
3917 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3918 mem_cgroup_swap_statistics(memcg, true);
3919 css_get(&memcg->css);
3922 * Migration does not charge the res_counter for the
3923 * replacement page, so leave it alone when phasing out the
3924 * page that is unused after the migration.
3927 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
3932 unlock_page_cgroup(pc);
3936 void mem_cgroup_uncharge_page(struct page *page)
3939 if (page_mapped(page))
3941 VM_BUG_ON_PAGE(page->mapping && !PageAnon(page), page);
3943 * If the page is in swap cache, uncharge should be deferred
3944 * to the swap path, which also properly accounts swap usage
3945 * and handles memcg lifetime.
3947 * Note that this check is not stable and reclaim may add the
3948 * page to swap cache at any time after this. However, if the
3949 * page is not in swap cache by the time page->mapcount hits
3950 * 0, there won't be any page table references to the swap
3951 * slot, and reclaim will free it and not actually write the
3954 if (PageSwapCache(page))
3956 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
3959 void mem_cgroup_uncharge_cache_page(struct page *page)
3961 VM_BUG_ON_PAGE(page_mapped(page), page);
3962 VM_BUG_ON_PAGE(page->mapping, page);
3963 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
3967 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3968 * In that cases, pages are freed continuously and we can expect pages
3969 * are in the same memcg. All these calls itself limits the number of
3970 * pages freed at once, then uncharge_start/end() is called properly.
3971 * This may be called prural(2) times in a context,
3974 void mem_cgroup_uncharge_start(void)
3976 current->memcg_batch.do_batch++;
3977 /* We can do nest. */
3978 if (current->memcg_batch.do_batch == 1) {
3979 current->memcg_batch.memcg = NULL;
3980 current->memcg_batch.nr_pages = 0;
3981 current->memcg_batch.memsw_nr_pages = 0;
3985 void mem_cgroup_uncharge_end(void)
3987 struct memcg_batch_info *batch = ¤t->memcg_batch;
3989 if (!batch->do_batch)
3993 if (batch->do_batch) /* If stacked, do nothing. */
3999 * This "batch->memcg" is valid without any css_get/put etc...
4000 * bacause we hide charges behind us.
4002 if (batch->nr_pages)
4003 res_counter_uncharge(&batch->memcg->res,
4004 batch->nr_pages * PAGE_SIZE);
4005 if (batch->memsw_nr_pages)
4006 res_counter_uncharge(&batch->memcg->memsw,
4007 batch->memsw_nr_pages * PAGE_SIZE);
4008 memcg_oom_recover(batch->memcg);
4009 /* forget this pointer (for sanity check) */
4010 batch->memcg = NULL;
4015 * called after __delete_from_swap_cache() and drop "page" account.
4016 * memcg information is recorded to swap_cgroup of "ent"
4019 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
4021 struct mem_cgroup *memcg;
4022 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
4024 if (!swapout) /* this was a swap cache but the swap is unused ! */
4025 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
4027 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
4030 * record memcg information, if swapout && memcg != NULL,
4031 * css_get() was called in uncharge().
4033 if (do_swap_account && swapout && memcg)
4034 swap_cgroup_record(ent, mem_cgroup_id(memcg));
4038 #ifdef CONFIG_MEMCG_SWAP
4040 * called from swap_entry_free(). remove record in swap_cgroup and
4041 * uncharge "memsw" account.
4043 void mem_cgroup_uncharge_swap(swp_entry_t ent)
4045 struct mem_cgroup *memcg;
4048 if (!do_swap_account)
4051 id = swap_cgroup_record(ent, 0);
4053 memcg = mem_cgroup_lookup(id);
4056 * We uncharge this because swap is freed. This memcg can
4057 * be obsolete one. We avoid calling css_tryget_online().
4059 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
4060 mem_cgroup_swap_statistics(memcg, false);
4061 css_put(&memcg->css);
4067 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4068 * @entry: swap entry to be moved
4069 * @from: mem_cgroup which the entry is moved from
4070 * @to: mem_cgroup which the entry is moved to
4072 * It succeeds only when the swap_cgroup's record for this entry is the same
4073 * as the mem_cgroup's id of @from.
4075 * Returns 0 on success, -EINVAL on failure.
4077 * The caller must have charged to @to, IOW, called res_counter_charge() about
4078 * both res and memsw, and called css_get().
4080 static int mem_cgroup_move_swap_account(swp_entry_t entry,
4081 struct mem_cgroup *from, struct mem_cgroup *to)
4083 unsigned short old_id, new_id;
4085 old_id = mem_cgroup_id(from);
4086 new_id = mem_cgroup_id(to);
4088 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
4089 mem_cgroup_swap_statistics(from, false);
4090 mem_cgroup_swap_statistics(to, true);
4092 * This function is only called from task migration context now.
4093 * It postpones res_counter and refcount handling till the end
4094 * of task migration(mem_cgroup_clear_mc()) for performance
4095 * improvement. But we cannot postpone css_get(to) because if
4096 * the process that has been moved to @to does swap-in, the
4097 * refcount of @to might be decreased to 0.
4099 * We are in attach() phase, so the cgroup is guaranteed to be
4100 * alive, so we can just call css_get().
4108 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
4109 struct mem_cgroup *from, struct mem_cgroup *to)
4116 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4119 void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
4120 struct mem_cgroup **memcgp)
4122 struct mem_cgroup *memcg = NULL;
4123 unsigned int nr_pages = 1;
4124 struct page_cgroup *pc;
4125 enum charge_type ctype;
4129 if (mem_cgroup_disabled())
4132 if (PageTransHuge(page))
4133 nr_pages <<= compound_order(page);
4135 pc = lookup_page_cgroup(page);
4136 lock_page_cgroup(pc);
4137 if (PageCgroupUsed(pc)) {
4138 memcg = pc->mem_cgroup;
4139 css_get(&memcg->css);
4141 * At migrating an anonymous page, its mapcount goes down
4142 * to 0 and uncharge() will be called. But, even if it's fully
4143 * unmapped, migration may fail and this page has to be
4144 * charged again. We set MIGRATION flag here and delay uncharge
4145 * until end_migration() is called
4147 * Corner Case Thinking
4149 * When the old page was mapped as Anon and it's unmap-and-freed
4150 * while migration was ongoing.
4151 * If unmap finds the old page, uncharge() of it will be delayed
4152 * until end_migration(). If unmap finds a new page, it's
4153 * uncharged when it make mapcount to be 1->0. If unmap code
4154 * finds swap_migration_entry, the new page will not be mapped
4155 * and end_migration() will find it(mapcount==0).
4158 * When the old page was mapped but migraion fails, the kernel
4159 * remaps it. A charge for it is kept by MIGRATION flag even
4160 * if mapcount goes down to 0. We can do remap successfully
4161 * without charging it again.
4164 * The "old" page is under lock_page() until the end of
4165 * migration, so, the old page itself will not be swapped-out.
4166 * If the new page is swapped out before end_migraton, our
4167 * hook to usual swap-out path will catch the event.
4170 SetPageCgroupMigration(pc);
4172 unlock_page_cgroup(pc);
4174 * If the page is not charged at this point,
4182 * We charge new page before it's used/mapped. So, even if unlock_page()
4183 * is called before end_migration, we can catch all events on this new
4184 * page. In the case new page is migrated but not remapped, new page's
4185 * mapcount will be finally 0 and we call uncharge in end_migration().
4188 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
4190 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
4192 * The page is committed to the memcg, but it's not actually
4193 * charged to the res_counter since we plan on replacing the
4194 * old one and only one page is going to be left afterwards.
4196 __mem_cgroup_commit_charge(memcg, newpage, nr_pages, ctype, false);
4199 /* remove redundant charge if migration failed*/
4200 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
4201 struct page *oldpage, struct page *newpage, bool migration_ok)
4203 struct page *used, *unused;
4204 struct page_cgroup *pc;
4210 if (!migration_ok) {
4217 anon = PageAnon(used);
4218 __mem_cgroup_uncharge_common(unused,
4219 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
4220 : MEM_CGROUP_CHARGE_TYPE_CACHE,
4222 css_put(&memcg->css);
4224 * We disallowed uncharge of pages under migration because mapcount
4225 * of the page goes down to zero, temporarly.
4226 * Clear the flag and check the page should be charged.
4228 pc = lookup_page_cgroup(oldpage);
4229 lock_page_cgroup(pc);
4230 ClearPageCgroupMigration(pc);
4231 unlock_page_cgroup(pc);
4234 * If a page is a file cache, radix-tree replacement is very atomic
4235 * and we can skip this check. When it was an Anon page, its mapcount
4236 * goes down to 0. But because we added MIGRATION flage, it's not
4237 * uncharged yet. There are several case but page->mapcount check
4238 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4239 * check. (see prepare_charge() also)
4242 mem_cgroup_uncharge_page(used);
4246 * At replace page cache, newpage is not under any memcg but it's on
4247 * LRU. So, this function doesn't touch res_counter but handles LRU
4248 * in correct way. Both pages are locked so we cannot race with uncharge.
4250 void mem_cgroup_replace_page_cache(struct page *oldpage,
4251 struct page *newpage)
4253 struct mem_cgroup *memcg = NULL;
4254 struct page_cgroup *pc;
4255 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
4257 if (mem_cgroup_disabled())
4260 pc = lookup_page_cgroup(oldpage);
4261 /* fix accounting on old pages */
4262 lock_page_cgroup(pc);
4263 if (PageCgroupUsed(pc)) {
4264 memcg = pc->mem_cgroup;
4265 mem_cgroup_charge_statistics(memcg, oldpage, false, -1);
4266 ClearPageCgroupUsed(pc);
4268 unlock_page_cgroup(pc);
4271 * When called from shmem_replace_page(), in some cases the
4272 * oldpage has already been charged, and in some cases not.
4277 * Even if newpage->mapping was NULL before starting replacement,
4278 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4279 * LRU while we overwrite pc->mem_cgroup.
4281 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
4284 #ifdef CONFIG_DEBUG_VM
4285 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
4287 struct page_cgroup *pc;
4289 pc = lookup_page_cgroup(page);
4291 * Can be NULL while feeding pages into the page allocator for
4292 * the first time, i.e. during boot or memory hotplug;
4293 * or when mem_cgroup_disabled().
4295 if (likely(pc) && PageCgroupUsed(pc))
4300 bool mem_cgroup_bad_page_check(struct page *page)
4302 if (mem_cgroup_disabled())
4305 return lookup_page_cgroup_used(page) != NULL;
4308 void mem_cgroup_print_bad_page(struct page *page)
4310 struct page_cgroup *pc;
4312 pc = lookup_page_cgroup_used(page);
4314 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4315 pc, pc->flags, pc->mem_cgroup);
4320 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
4321 unsigned long long val)
4324 u64 memswlimit, memlimit;
4326 int children = mem_cgroup_count_children(memcg);
4327 u64 curusage, oldusage;
4331 * For keeping hierarchical_reclaim simple, how long we should retry
4332 * is depends on callers. We set our retry-count to be function
4333 * of # of children which we should visit in this loop.
4335 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
4337 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4340 while (retry_count) {
4341 if (signal_pending(current)) {
4346 * Rather than hide all in some function, I do this in
4347 * open coded manner. You see what this really does.
4348 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4350 mutex_lock(&set_limit_mutex);
4351 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4352 if (memswlimit < val) {
4354 mutex_unlock(&set_limit_mutex);
4358 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4362 ret = res_counter_set_limit(&memcg->res, val);
4364 if (memswlimit == val)
4365 memcg->memsw_is_minimum = true;
4367 memcg->memsw_is_minimum = false;
4369 mutex_unlock(&set_limit_mutex);
4374 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4375 MEM_CGROUP_RECLAIM_SHRINK);
4376 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
4377 /* Usage is reduced ? */
4378 if (curusage >= oldusage)
4381 oldusage = curusage;
4383 if (!ret && enlarge)
4384 memcg_oom_recover(memcg);
4389 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
4390 unsigned long long val)
4393 u64 memlimit, memswlimit, oldusage, curusage;
4394 int children = mem_cgroup_count_children(memcg);
4398 /* see mem_cgroup_resize_res_limit */
4399 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
4400 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4401 while (retry_count) {
4402 if (signal_pending(current)) {
4407 * Rather than hide all in some function, I do this in
4408 * open coded manner. You see what this really does.
4409 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4411 mutex_lock(&set_limit_mutex);
4412 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4413 if (memlimit > val) {
4415 mutex_unlock(&set_limit_mutex);
4418 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4419 if (memswlimit < val)
4421 ret = res_counter_set_limit(&memcg->memsw, val);
4423 if (memlimit == val)
4424 memcg->memsw_is_minimum = true;
4426 memcg->memsw_is_minimum = false;
4428 mutex_unlock(&set_limit_mutex);
4433 mem_cgroup_reclaim(memcg, GFP_KERNEL,
4434 MEM_CGROUP_RECLAIM_NOSWAP |
4435 MEM_CGROUP_RECLAIM_SHRINK);
4436 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
4437 /* Usage is reduced ? */
4438 if (curusage >= oldusage)
4441 oldusage = curusage;
4443 if (!ret && enlarge)
4444 memcg_oom_recover(memcg);
4448 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
4450 unsigned long *total_scanned)
4452 unsigned long nr_reclaimed = 0;
4453 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
4454 unsigned long reclaimed;
4456 struct mem_cgroup_tree_per_zone *mctz;
4457 unsigned long long excess;
4458 unsigned long nr_scanned;
4463 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
4465 * This loop can run a while, specially if mem_cgroup's continuously
4466 * keep exceeding their soft limit and putting the system under
4473 mz = mem_cgroup_largest_soft_limit_node(mctz);
4478 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
4479 gfp_mask, &nr_scanned);
4480 nr_reclaimed += reclaimed;
4481 *total_scanned += nr_scanned;
4482 spin_lock(&mctz->lock);
4485 * If we failed to reclaim anything from this memory cgroup
4486 * it is time to move on to the next cgroup
4492 * Loop until we find yet another one.
4494 * By the time we get the soft_limit lock
4495 * again, someone might have aded the
4496 * group back on the RB tree. Iterate to
4497 * make sure we get a different mem.
4498 * mem_cgroup_largest_soft_limit_node returns
4499 * NULL if no other cgroup is present on
4503 __mem_cgroup_largest_soft_limit_node(mctz);
4505 css_put(&next_mz->memcg->css);
4506 else /* next_mz == NULL or other memcg */
4510 __mem_cgroup_remove_exceeded(mz, mctz);
4511 excess = res_counter_soft_limit_excess(&mz->memcg->res);
4513 * One school of thought says that we should not add
4514 * back the node to the tree if reclaim returns 0.
4515 * But our reclaim could return 0, simply because due
4516 * to priority we are exposing a smaller subset of
4517 * memory to reclaim from. Consider this as a longer
4520 /* If excess == 0, no tree ops */
4521 __mem_cgroup_insert_exceeded(mz, mctz, excess);
4522 spin_unlock(&mctz->lock);
4523 css_put(&mz->memcg->css);
4526 * Could not reclaim anything and there are no more
4527 * mem cgroups to try or we seem to be looping without
4528 * reclaiming anything.
4530 if (!nr_reclaimed &&
4532 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
4534 } while (!nr_reclaimed);
4536 css_put(&next_mz->memcg->css);
4537 return nr_reclaimed;
4541 * mem_cgroup_force_empty_list - clears LRU of a group
4542 * @memcg: group to clear
4545 * @lru: lru to to clear
4547 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4548 * reclaim the pages page themselves - pages are moved to the parent (or root)
4551 static void mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
4552 int node, int zid, enum lru_list lru)
4554 struct lruvec *lruvec;
4555 unsigned long flags;
4556 struct list_head *list;
4560 zone = &NODE_DATA(node)->node_zones[zid];
4561 lruvec = mem_cgroup_zone_lruvec(zone, memcg);
4562 list = &lruvec->lists[lru];
4566 struct page_cgroup *pc;
4569 spin_lock_irqsave(&zone->lru_lock, flags);
4570 if (list_empty(list)) {
4571 spin_unlock_irqrestore(&zone->lru_lock, flags);
4574 page = list_entry(list->prev, struct page, lru);
4576 list_move(&page->lru, list);
4578 spin_unlock_irqrestore(&zone->lru_lock, flags);
4581 spin_unlock_irqrestore(&zone->lru_lock, flags);
4583 pc = lookup_page_cgroup(page);
4585 if (mem_cgroup_move_parent(page, pc, memcg)) {
4586 /* found lock contention or "pc" is obsolete. */
4591 } while (!list_empty(list));
4595 * make mem_cgroup's charge to be 0 if there is no task by moving
4596 * all the charges and pages to the parent.
4597 * This enables deleting this mem_cgroup.
4599 * Caller is responsible for holding css reference on the memcg.
4601 static void mem_cgroup_reparent_charges(struct mem_cgroup *memcg)
4607 /* This is for making all *used* pages to be on LRU. */
4608 lru_add_drain_all();
4609 drain_all_stock_sync(memcg);
4610 mem_cgroup_start_move(memcg);
4611 for_each_node_state(node, N_MEMORY) {
4612 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4615 mem_cgroup_force_empty_list(memcg,
4620 mem_cgroup_end_move(memcg);
4621 memcg_oom_recover(memcg);
4625 * Kernel memory may not necessarily be trackable to a specific
4626 * process. So they are not migrated, and therefore we can't
4627 * expect their value to drop to 0 here.
4628 * Having res filled up with kmem only is enough.
4630 * This is a safety check because mem_cgroup_force_empty_list
4631 * could have raced with mem_cgroup_replace_page_cache callers
4632 * so the lru seemed empty but the page could have been added
4633 * right after the check. RES_USAGE should be safe as we always
4634 * charge before adding to the LRU.
4636 usage = res_counter_read_u64(&memcg->res, RES_USAGE) -
4637 res_counter_read_u64(&memcg->kmem, RES_USAGE);
4638 } while (usage > 0);
4642 * Test whether @memcg has children, dead or alive. Note that this
4643 * function doesn't care whether @memcg has use_hierarchy enabled and
4644 * returns %true if there are child csses according to the cgroup
4645 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
4647 static inline bool memcg_has_children(struct mem_cgroup *memcg)
4652 * The lock does not prevent addition or deletion of children, but
4653 * it prevents a new child from being initialized based on this
4654 * parent in css_online(), so it's enough to decide whether
4655 * hierarchically inherited attributes can still be changed or not.
4657 lockdep_assert_held(&memcg_create_mutex);
4660 ret = css_next_child(NULL, &memcg->css);
4666 * Reclaims as many pages from the given memcg as possible and moves
4667 * the rest to the parent.
4669 * Caller is responsible for holding css reference for memcg.
4671 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
4673 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
4675 /* we call try-to-free pages for make this cgroup empty */
4676 lru_add_drain_all();
4677 /* try to free all pages in this cgroup */
4678 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
4681 if (signal_pending(current))
4684 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
4688 /* maybe some writeback is necessary */
4689 congestion_wait(BLK_RW_ASYNC, HZ/10);
4697 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
4698 char *buf, size_t nbytes,
4701 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4703 if (mem_cgroup_is_root(memcg))
4705 return mem_cgroup_force_empty(memcg) ?: nbytes;
4708 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
4711 return mem_cgroup_from_css(css)->use_hierarchy;
4714 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
4715 struct cftype *cft, u64 val)
4718 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4719 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
4721 mutex_lock(&memcg_create_mutex);
4723 if (memcg->use_hierarchy == val)
4727 * If parent's use_hierarchy is set, we can't make any modifications
4728 * in the child subtrees. If it is unset, then the change can
4729 * occur, provided the current cgroup has no children.
4731 * For the root cgroup, parent_mem is NULL, we allow value to be
4732 * set if there are no children.
4734 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
4735 (val == 1 || val == 0)) {
4736 if (!memcg_has_children(memcg))
4737 memcg->use_hierarchy = val;
4744 mutex_unlock(&memcg_create_mutex);
4749 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
4752 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4753 enum res_type type = MEMFILE_TYPE(cft->private);
4754 int name = MEMFILE_ATTR(cft->private);
4758 return res_counter_read_u64(&memcg->res, name);
4760 return res_counter_read_u64(&memcg->memsw, name);
4762 return res_counter_read_u64(&memcg->kmem, name);
4769 #ifdef CONFIG_MEMCG_KMEM
4770 /* should be called with activate_kmem_mutex held */
4771 static int __memcg_activate_kmem(struct mem_cgroup *memcg,
4772 unsigned long long limit)
4777 if (memcg_kmem_is_active(memcg))
4781 * We are going to allocate memory for data shared by all memory
4782 * cgroups so let's stop accounting here.
4784 memcg_stop_kmem_account();
4787 * For simplicity, we won't allow this to be disabled. It also can't
4788 * be changed if the cgroup has children already, or if tasks had
4791 * If tasks join before we set the limit, a person looking at
4792 * kmem.usage_in_bytes will have no way to determine when it took
4793 * place, which makes the value quite meaningless.
4795 * After it first became limited, changes in the value of the limit are
4796 * of course permitted.
4798 mutex_lock(&memcg_create_mutex);
4799 if (cgroup_has_tasks(memcg->css.cgroup) ||
4800 (memcg->use_hierarchy && memcg_has_children(memcg)))
4802 mutex_unlock(&memcg_create_mutex);
4806 memcg_id = ida_simple_get(&kmem_limited_groups,
4807 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
4814 * Make sure we have enough space for this cgroup in each root cache's
4817 mutex_lock(&memcg_slab_mutex);
4818 err = memcg_update_all_caches(memcg_id + 1);
4819 mutex_unlock(&memcg_slab_mutex);
4823 memcg->kmemcg_id = memcg_id;
4824 INIT_LIST_HEAD(&memcg->memcg_slab_caches);
4827 * We couldn't have accounted to this cgroup, because it hasn't got the
4828 * active bit set yet, so this should succeed.
4830 err = res_counter_set_limit(&memcg->kmem, limit);
4833 static_key_slow_inc(&memcg_kmem_enabled_key);
4835 * Setting the active bit after enabling static branching will
4836 * guarantee no one starts accounting before all call sites are
4839 memcg_kmem_set_active(memcg);
4841 memcg_resume_kmem_account();
4845 ida_simple_remove(&kmem_limited_groups, memcg_id);
4849 static int memcg_activate_kmem(struct mem_cgroup *memcg,
4850 unsigned long long limit)
4854 mutex_lock(&activate_kmem_mutex);
4855 ret = __memcg_activate_kmem(memcg, limit);
4856 mutex_unlock(&activate_kmem_mutex);
4860 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
4861 unsigned long long val)
4865 if (!memcg_kmem_is_active(memcg))
4866 ret = memcg_activate_kmem(memcg, val);
4868 ret = res_counter_set_limit(&memcg->kmem, val);
4872 static int memcg_propagate_kmem(struct mem_cgroup *memcg)
4875 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4880 mutex_lock(&activate_kmem_mutex);
4882 * If the parent cgroup is not kmem-active now, it cannot be activated
4883 * after this point, because it has at least one child already.
4885 if (memcg_kmem_is_active(parent))
4886 ret = __memcg_activate_kmem(memcg, RES_COUNTER_MAX);
4887 mutex_unlock(&activate_kmem_mutex);
4891 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
4892 unsigned long long val)
4896 #endif /* CONFIG_MEMCG_KMEM */
4899 * The user of this function is...
4902 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
4903 char *buf, size_t nbytes, loff_t off)
4905 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4908 unsigned long long val;
4911 buf = strstrip(buf);
4912 type = MEMFILE_TYPE(of_cft(of)->private);
4913 name = MEMFILE_ATTR(of_cft(of)->private);
4917 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
4921 /* This function does all necessary parse...reuse it */
4922 ret = res_counter_memparse_write_strategy(buf, &val);
4926 ret = mem_cgroup_resize_limit(memcg, val);
4927 else if (type == _MEMSWAP)
4928 ret = mem_cgroup_resize_memsw_limit(memcg, val);
4929 else if (type == _KMEM)
4930 ret = memcg_update_kmem_limit(memcg, val);
4934 case RES_SOFT_LIMIT:
4935 ret = res_counter_memparse_write_strategy(buf, &val);
4939 * For memsw, soft limits are hard to implement in terms
4940 * of semantics, for now, we support soft limits for
4941 * control without swap
4944 ret = res_counter_set_soft_limit(&memcg->res, val);
4949 ret = -EINVAL; /* should be BUG() ? */
4952 return ret ?: nbytes;
4955 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
4956 unsigned long long *mem_limit, unsigned long long *memsw_limit)
4958 unsigned long long min_limit, min_memsw_limit, tmp;
4960 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
4961 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4962 if (!memcg->use_hierarchy)
4965 while (memcg->css.parent) {
4966 memcg = mem_cgroup_from_css(memcg->css.parent);
4967 if (!memcg->use_hierarchy)
4969 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
4970 min_limit = min(min_limit, tmp);
4971 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4972 min_memsw_limit = min(min_memsw_limit, tmp);
4975 *mem_limit = min_limit;
4976 *memsw_limit = min_memsw_limit;
4979 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
4980 size_t nbytes, loff_t off)
4982 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
4986 type = MEMFILE_TYPE(of_cft(of)->private);
4987 name = MEMFILE_ATTR(of_cft(of)->private);
4992 res_counter_reset_max(&memcg->res);
4993 else if (type == _MEMSWAP)
4994 res_counter_reset_max(&memcg->memsw);
4995 else if (type == _KMEM)
4996 res_counter_reset_max(&memcg->kmem);
5002 res_counter_reset_failcnt(&memcg->res);
5003 else if (type == _MEMSWAP)
5004 res_counter_reset_failcnt(&memcg->memsw);
5005 else if (type == _KMEM)
5006 res_counter_reset_failcnt(&memcg->kmem);
5015 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
5018 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
5022 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
5023 struct cftype *cft, u64 val)
5025 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5027 if (val >= (1 << NR_MOVE_TYPE))
5031 * No kind of locking is needed in here, because ->can_attach() will
5032 * check this value once in the beginning of the process, and then carry
5033 * on with stale data. This means that changes to this value will only
5034 * affect task migrations starting after the change.
5036 memcg->move_charge_at_immigrate = val;
5040 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
5041 struct cftype *cft, u64 val)
5048 static int memcg_numa_stat_show(struct seq_file *m, void *v)
5052 unsigned int lru_mask;
5055 static const struct numa_stat stats[] = {
5056 { "total", LRU_ALL },
5057 { "file", LRU_ALL_FILE },
5058 { "anon", LRU_ALL_ANON },
5059 { "unevictable", BIT(LRU_UNEVICTABLE) },
5061 const struct numa_stat *stat;
5064 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5066 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5067 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
5068 seq_printf(m, "%s=%lu", stat->name, nr);
5069 for_each_node_state(nid, N_MEMORY) {
5070 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
5072 seq_printf(m, " N%d=%lu", nid, nr);
5077 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
5078 struct mem_cgroup *iter;
5081 for_each_mem_cgroup_tree(iter, memcg)
5082 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
5083 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
5084 for_each_node_state(nid, N_MEMORY) {
5086 for_each_mem_cgroup_tree(iter, memcg)
5087 nr += mem_cgroup_node_nr_lru_pages(
5088 iter, nid, stat->lru_mask);
5089 seq_printf(m, " N%d=%lu", nid, nr);
5096 #endif /* CONFIG_NUMA */
5098 static inline void mem_cgroup_lru_names_not_uptodate(void)
5100 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
5103 static int memcg_stat_show(struct seq_file *m, void *v)
5105 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5106 struct mem_cgroup *mi;
5109 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5110 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5112 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
5113 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
5116 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
5117 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
5118 mem_cgroup_read_events(memcg, i));
5120 for (i = 0; i < NR_LRU_LISTS; i++)
5121 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
5122 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
5124 /* Hierarchical information */
5126 unsigned long long limit, memsw_limit;
5127 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
5128 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
5129 if (do_swap_account)
5130 seq_printf(m, "hierarchical_memsw_limit %llu\n",
5134 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
5137 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
5139 for_each_mem_cgroup_tree(mi, memcg)
5140 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
5141 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
5144 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
5145 unsigned long long val = 0;
5147 for_each_mem_cgroup_tree(mi, memcg)
5148 val += mem_cgroup_read_events(mi, i);
5149 seq_printf(m, "total_%s %llu\n",
5150 mem_cgroup_events_names[i], val);
5153 for (i = 0; i < NR_LRU_LISTS; i++) {
5154 unsigned long long val = 0;
5156 for_each_mem_cgroup_tree(mi, memcg)
5157 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
5158 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
5161 #ifdef CONFIG_DEBUG_VM
5164 struct mem_cgroup_per_zone *mz;
5165 struct zone_reclaim_stat *rstat;
5166 unsigned long recent_rotated[2] = {0, 0};
5167 unsigned long recent_scanned[2] = {0, 0};
5169 for_each_online_node(nid)
5170 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
5171 mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
5172 rstat = &mz->lruvec.reclaim_stat;
5174 recent_rotated[0] += rstat->recent_rotated[0];
5175 recent_rotated[1] += rstat->recent_rotated[1];
5176 recent_scanned[0] += rstat->recent_scanned[0];
5177 recent_scanned[1] += rstat->recent_scanned[1];
5179 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
5180 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
5181 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
5182 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
5189 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
5192 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5194 return mem_cgroup_swappiness(memcg);
5197 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
5198 struct cftype *cft, u64 val)
5200 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5206 memcg->swappiness = val;
5208 vm_swappiness = val;
5213 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
5215 struct mem_cgroup_threshold_ary *t;
5221 t = rcu_dereference(memcg->thresholds.primary);
5223 t = rcu_dereference(memcg->memsw_thresholds.primary);
5229 usage = res_counter_read_u64(&memcg->res, RES_USAGE);
5231 usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
5234 * current_threshold points to threshold just below or equal to usage.
5235 * If it's not true, a threshold was crossed after last
5236 * call of __mem_cgroup_threshold().
5238 i = t->current_threshold;
5241 * Iterate backward over array of thresholds starting from
5242 * current_threshold and check if a threshold is crossed.
5243 * If none of thresholds below usage is crossed, we read
5244 * only one element of the array here.
5246 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
5247 eventfd_signal(t->entries[i].eventfd, 1);
5249 /* i = current_threshold + 1 */
5253 * Iterate forward over array of thresholds starting from
5254 * current_threshold+1 and check if a threshold is crossed.
5255 * If none of thresholds above usage is crossed, we read
5256 * only one element of the array here.
5258 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
5259 eventfd_signal(t->entries[i].eventfd, 1);
5261 /* Update current_threshold */
5262 t->current_threshold = i - 1;
5267 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
5270 __mem_cgroup_threshold(memcg, false);
5271 if (do_swap_account)
5272 __mem_cgroup_threshold(memcg, true);
5274 memcg = parent_mem_cgroup(memcg);
5278 static int compare_thresholds(const void *a, const void *b)
5280 const struct mem_cgroup_threshold *_a = a;
5281 const struct mem_cgroup_threshold *_b = b;
5283 if (_a->threshold > _b->threshold)
5286 if (_a->threshold < _b->threshold)
5292 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
5294 struct mem_cgroup_eventfd_list *ev;
5296 spin_lock(&memcg_oom_lock);
5298 list_for_each_entry(ev, &memcg->oom_notify, list)
5299 eventfd_signal(ev->eventfd, 1);
5301 spin_unlock(&memcg_oom_lock);
5305 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
5307 struct mem_cgroup *iter;
5309 for_each_mem_cgroup_tree(iter, memcg)
5310 mem_cgroup_oom_notify_cb(iter);
5313 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
5314 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
5316 struct mem_cgroup_thresholds *thresholds;
5317 struct mem_cgroup_threshold_ary *new;
5318 u64 threshold, usage;
5321 ret = res_counter_memparse_write_strategy(args, &threshold);
5325 mutex_lock(&memcg->thresholds_lock);
5328 thresholds = &memcg->thresholds;
5329 usage = res_counter_read_u64(&memcg->res, RES_USAGE);
5330 } else if (type == _MEMSWAP) {
5331 thresholds = &memcg->memsw_thresholds;
5332 usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
5336 /* Check if a threshold crossed before adding a new one */
5337 if (thresholds->primary)
5338 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5340 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
5342 /* Allocate memory for new array of thresholds */
5343 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
5351 /* Copy thresholds (if any) to new array */
5352 if (thresholds->primary) {
5353 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
5354 sizeof(struct mem_cgroup_threshold));
5357 /* Add new threshold */
5358 new->entries[size - 1].eventfd = eventfd;
5359 new->entries[size - 1].threshold = threshold;
5361 /* Sort thresholds. Registering of new threshold isn't time-critical */
5362 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
5363 compare_thresholds, NULL);
5365 /* Find current threshold */
5366 new->current_threshold = -1;
5367 for (i = 0; i < size; i++) {
5368 if (new->entries[i].threshold <= usage) {
5370 * new->current_threshold will not be used until
5371 * rcu_assign_pointer(), so it's safe to increment
5374 ++new->current_threshold;
5379 /* Free old spare buffer and save old primary buffer as spare */
5380 kfree(thresholds->spare);
5381 thresholds->spare = thresholds->primary;
5383 rcu_assign_pointer(thresholds->primary, new);
5385 /* To be sure that nobody uses thresholds */
5389 mutex_unlock(&memcg->thresholds_lock);
5394 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
5395 struct eventfd_ctx *eventfd, const char *args)
5397 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
5400 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
5401 struct eventfd_ctx *eventfd, const char *args)
5403 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
5406 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5407 struct eventfd_ctx *eventfd, enum res_type type)
5409 struct mem_cgroup_thresholds *thresholds;
5410 struct mem_cgroup_threshold_ary *new;
5414 mutex_lock(&memcg->thresholds_lock);
5417 thresholds = &memcg->thresholds;
5418 usage = res_counter_read_u64(&memcg->res, RES_USAGE);
5419 } else if (type == _MEMSWAP) {
5420 thresholds = &memcg->memsw_thresholds;
5421 usage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
5425 if (!thresholds->primary)
5428 /* Check if a threshold crossed before removing */
5429 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
5431 /* Calculate new number of threshold */
5433 for (i = 0; i < thresholds->primary->size; i++) {
5434 if (thresholds->primary->entries[i].eventfd != eventfd)
5438 new = thresholds->spare;
5440 /* Set thresholds array to NULL if we don't have thresholds */
5449 /* Copy thresholds and find current threshold */
5450 new->current_threshold = -1;
5451 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
5452 if (thresholds->primary->entries[i].eventfd == eventfd)
5455 new->entries[j] = thresholds->primary->entries[i];
5456 if (new->entries[j].threshold <= usage) {
5458 * new->current_threshold will not be used
5459 * until rcu_assign_pointer(), so it's safe to increment
5462 ++new->current_threshold;
5468 /* Swap primary and spare array */
5469 thresholds->spare = thresholds->primary;
5470 /* If all events are unregistered, free the spare array */
5472 kfree(thresholds->spare);
5473 thresholds->spare = NULL;
5476 rcu_assign_pointer(thresholds->primary, new);
5478 /* To be sure that nobody uses thresholds */
5481 mutex_unlock(&memcg->thresholds_lock);
5484 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5485 struct eventfd_ctx *eventfd)
5487 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
5490 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
5491 struct eventfd_ctx *eventfd)
5493 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
5496 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
5497 struct eventfd_ctx *eventfd, const char *args)
5499 struct mem_cgroup_eventfd_list *event;
5501 event = kmalloc(sizeof(*event), GFP_KERNEL);
5505 spin_lock(&memcg_oom_lock);
5507 event->eventfd = eventfd;
5508 list_add(&event->list, &memcg->oom_notify);
5510 /* already in OOM ? */
5511 if (atomic_read(&memcg->under_oom))
5512 eventfd_signal(eventfd, 1);
5513 spin_unlock(&memcg_oom_lock);
5518 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
5519 struct eventfd_ctx *eventfd)
5521 struct mem_cgroup_eventfd_list *ev, *tmp;
5523 spin_lock(&memcg_oom_lock);
5525 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
5526 if (ev->eventfd == eventfd) {
5527 list_del(&ev->list);
5532 spin_unlock(&memcg_oom_lock);
5535 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
5537 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
5539 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
5540 seq_printf(sf, "under_oom %d\n", (bool)atomic_read(&memcg->under_oom));
5544 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
5545 struct cftype *cft, u64 val)
5547 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5549 /* cannot set to root cgroup and only 0 and 1 are allowed */
5550 if (!css->parent || !((val == 0) || (val == 1)))
5553 memcg->oom_kill_disable = val;
5555 memcg_oom_recover(memcg);
5560 #ifdef CONFIG_MEMCG_KMEM
5561 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5565 memcg->kmemcg_id = -1;
5566 ret = memcg_propagate_kmem(memcg);
5570 return mem_cgroup_sockets_init(memcg, ss);
5573 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5575 mem_cgroup_sockets_destroy(memcg);
5578 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5580 if (!memcg_kmem_is_active(memcg))
5584 * kmem charges can outlive the cgroup. In the case of slab
5585 * pages, for instance, a page contain objects from various
5586 * processes. As we prevent from taking a reference for every
5587 * such allocation we have to be careful when doing uncharge
5588 * (see memcg_uncharge_kmem) and here during offlining.
5590 * The idea is that that only the _last_ uncharge which sees
5591 * the dead memcg will drop the last reference. An additional
5592 * reference is taken here before the group is marked dead
5593 * which is then paired with css_put during uncharge resp. here.
5595 * Although this might sound strange as this path is called from
5596 * css_offline() when the referencemight have dropped down to 0 and
5597 * shouldn't be incremented anymore (css_tryget_online() would
5598 * fail) we do not have other options because of the kmem
5599 * allocations lifetime.
5601 css_get(&memcg->css);
5603 memcg_kmem_mark_dead(memcg);
5605 if (res_counter_read_u64(&memcg->kmem, RES_USAGE) != 0)
5608 if (memcg_kmem_test_and_clear_dead(memcg))
5609 css_put(&memcg->css);
5612 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
5617 static void memcg_destroy_kmem(struct mem_cgroup *memcg)
5621 static void kmem_cgroup_css_offline(struct mem_cgroup *memcg)
5627 * DO NOT USE IN NEW FILES.
5629 * "cgroup.event_control" implementation.
5631 * This is way over-engineered. It tries to support fully configurable
5632 * events for each user. Such level of flexibility is completely
5633 * unnecessary especially in the light of the planned unified hierarchy.
5635 * Please deprecate this and replace with something simpler if at all
5640 * Unregister event and free resources.
5642 * Gets called from workqueue.
5644 static void memcg_event_remove(struct work_struct *work)
5646 struct mem_cgroup_event *event =
5647 container_of(work, struct mem_cgroup_event, remove);
5648 struct mem_cgroup *memcg = event->memcg;
5650 remove_wait_queue(event->wqh, &event->wait);
5652 event->unregister_event(memcg, event->eventfd);
5654 /* Notify userspace the event is going away. */
5655 eventfd_signal(event->eventfd, 1);
5657 eventfd_ctx_put(event->eventfd);
5659 css_put(&memcg->css);
5663 * Gets called on POLLHUP on eventfd when user closes it.
5665 * Called with wqh->lock held and interrupts disabled.
5667 static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
5668 int sync, void *key)
5670 struct mem_cgroup_event *event =
5671 container_of(wait, struct mem_cgroup_event, wait);
5672 struct mem_cgroup *memcg = event->memcg;
5673 unsigned long flags = (unsigned long)key;
5675 if (flags & POLLHUP) {
5677 * If the event has been detached at cgroup removal, we
5678 * can simply return knowing the other side will cleanup
5681 * We can't race against event freeing since the other
5682 * side will require wqh->lock via remove_wait_queue(),
5685 spin_lock(&memcg->event_list_lock);
5686 if (!list_empty(&event->list)) {
5687 list_del_init(&event->list);
5689 * We are in atomic context, but cgroup_event_remove()
5690 * may sleep, so we have to call it in workqueue.
5692 schedule_work(&event->remove);
5694 spin_unlock(&memcg->event_list_lock);
5700 static void memcg_event_ptable_queue_proc(struct file *file,
5701 wait_queue_head_t *wqh, poll_table *pt)
5703 struct mem_cgroup_event *event =
5704 container_of(pt, struct mem_cgroup_event, pt);
5707 add_wait_queue(wqh, &event->wait);
5711 * DO NOT USE IN NEW FILES.
5713 * Parse input and register new cgroup event handler.
5715 * Input must be in format '<event_fd> <control_fd> <args>'.
5716 * Interpretation of args is defined by control file implementation.
5718 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
5719 char *buf, size_t nbytes, loff_t off)
5721 struct cgroup_subsys_state *css = of_css(of);
5722 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5723 struct mem_cgroup_event *event;
5724 struct cgroup_subsys_state *cfile_css;
5725 unsigned int efd, cfd;
5732 buf = strstrip(buf);
5734 efd = simple_strtoul(buf, &endp, 10);
5739 cfd = simple_strtoul(buf, &endp, 10);
5740 if ((*endp != ' ') && (*endp != '\0'))
5744 event = kzalloc(sizeof(*event), GFP_KERNEL);
5748 event->memcg = memcg;
5749 INIT_LIST_HEAD(&event->list);
5750 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
5751 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
5752 INIT_WORK(&event->remove, memcg_event_remove);
5760 event->eventfd = eventfd_ctx_fileget(efile.file);
5761 if (IS_ERR(event->eventfd)) {
5762 ret = PTR_ERR(event->eventfd);
5769 goto out_put_eventfd;
5772 /* the process need read permission on control file */
5773 /* AV: shouldn't we check that it's been opened for read instead? */
5774 ret = inode_permission(file_inode(cfile.file), MAY_READ);
5779 * Determine the event callbacks and set them in @event. This used
5780 * to be done via struct cftype but cgroup core no longer knows
5781 * about these events. The following is crude but the whole thing
5782 * is for compatibility anyway.
5784 * DO NOT ADD NEW FILES.
5786 name = cfile.file->f_dentry->d_name.name;
5788 if (!strcmp(name, "memory.usage_in_bytes")) {
5789 event->register_event = mem_cgroup_usage_register_event;
5790 event->unregister_event = mem_cgroup_usage_unregister_event;
5791 } else if (!strcmp(name, "memory.oom_control")) {
5792 event->register_event = mem_cgroup_oom_register_event;
5793 event->unregister_event = mem_cgroup_oom_unregister_event;
5794 } else if (!strcmp(name, "memory.pressure_level")) {
5795 event->register_event = vmpressure_register_event;
5796 event->unregister_event = vmpressure_unregister_event;
5797 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
5798 event->register_event = memsw_cgroup_usage_register_event;
5799 event->unregister_event = memsw_cgroup_usage_unregister_event;
5806 * Verify @cfile should belong to @css. Also, remaining events are
5807 * automatically removed on cgroup destruction but the removal is
5808 * asynchronous, so take an extra ref on @css.
5810 cfile_css = css_tryget_online_from_dir(cfile.file->f_dentry->d_parent,
5811 &memory_cgrp_subsys);
5813 if (IS_ERR(cfile_css))
5815 if (cfile_css != css) {
5820 ret = event->register_event(memcg, event->eventfd, buf);
5824 efile.file->f_op->poll(efile.file, &event->pt);
5826 spin_lock(&memcg->event_list_lock);
5827 list_add(&event->list, &memcg->event_list);
5828 spin_unlock(&memcg->event_list_lock);
5840 eventfd_ctx_put(event->eventfd);
5849 static struct cftype mem_cgroup_files[] = {
5851 .name = "usage_in_bytes",
5852 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
5853 .read_u64 = mem_cgroup_read_u64,
5856 .name = "max_usage_in_bytes",
5857 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
5858 .write = mem_cgroup_reset,
5859 .read_u64 = mem_cgroup_read_u64,
5862 .name = "limit_in_bytes",
5863 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
5864 .write = mem_cgroup_write,
5865 .read_u64 = mem_cgroup_read_u64,
5868 .name = "soft_limit_in_bytes",
5869 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
5870 .write = mem_cgroup_write,
5871 .read_u64 = mem_cgroup_read_u64,
5875 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
5876 .write = mem_cgroup_reset,
5877 .read_u64 = mem_cgroup_read_u64,
5881 .seq_show = memcg_stat_show,
5884 .name = "force_empty",
5885 .write = mem_cgroup_force_empty_write,
5888 .name = "use_hierarchy",
5889 .write_u64 = mem_cgroup_hierarchy_write,
5890 .read_u64 = mem_cgroup_hierarchy_read,
5893 .name = "cgroup.event_control", /* XXX: for compat */
5894 .write = memcg_write_event_control,
5895 .flags = CFTYPE_NO_PREFIX,
5899 .name = "swappiness",
5900 .read_u64 = mem_cgroup_swappiness_read,
5901 .write_u64 = mem_cgroup_swappiness_write,
5904 .name = "move_charge_at_immigrate",
5905 .read_u64 = mem_cgroup_move_charge_read,
5906 .write_u64 = mem_cgroup_move_charge_write,
5909 .name = "oom_control",
5910 .seq_show = mem_cgroup_oom_control_read,
5911 .write_u64 = mem_cgroup_oom_control_write,
5912 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
5915 .name = "pressure_level",
5919 .name = "numa_stat",
5920 .seq_show = memcg_numa_stat_show,
5923 #ifdef CONFIG_MEMCG_KMEM
5925 .name = "kmem.limit_in_bytes",
5926 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
5927 .write = mem_cgroup_write,
5928 .read_u64 = mem_cgroup_read_u64,
5931 .name = "kmem.usage_in_bytes",
5932 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
5933 .read_u64 = mem_cgroup_read_u64,
5936 .name = "kmem.failcnt",
5937 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
5938 .write = mem_cgroup_reset,
5939 .read_u64 = mem_cgroup_read_u64,
5942 .name = "kmem.max_usage_in_bytes",
5943 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
5944 .write = mem_cgroup_reset,
5945 .read_u64 = mem_cgroup_read_u64,
5947 #ifdef CONFIG_SLABINFO
5949 .name = "kmem.slabinfo",
5950 .seq_show = mem_cgroup_slabinfo_read,
5954 { }, /* terminate */
5957 #ifdef CONFIG_MEMCG_SWAP
5958 static struct cftype memsw_cgroup_files[] = {
5960 .name = "memsw.usage_in_bytes",
5961 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
5962 .read_u64 = mem_cgroup_read_u64,
5965 .name = "memsw.max_usage_in_bytes",
5966 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
5967 .write = mem_cgroup_reset,
5968 .read_u64 = mem_cgroup_read_u64,
5971 .name = "memsw.limit_in_bytes",
5972 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
5973 .write = mem_cgroup_write,
5974 .read_u64 = mem_cgroup_read_u64,
5977 .name = "memsw.failcnt",
5978 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
5979 .write = mem_cgroup_reset,
5980 .read_u64 = mem_cgroup_read_u64,
5982 { }, /* terminate */
5985 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
5987 struct mem_cgroup_per_node *pn;
5988 struct mem_cgroup_per_zone *mz;
5989 int zone, tmp = node;
5991 * This routine is called against possible nodes.
5992 * But it's BUG to call kmalloc() against offline node.
5994 * TODO: this routine can waste much memory for nodes which will
5995 * never be onlined. It's better to use memory hotplug callback
5998 if (!node_state(node, N_NORMAL_MEMORY))
6000 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
6004 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6005 mz = &pn->zoneinfo[zone];
6006 lruvec_init(&mz->lruvec);
6007 mz->usage_in_excess = 0;
6008 mz->on_tree = false;
6011 memcg->nodeinfo[node] = pn;
6015 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
6017 kfree(memcg->nodeinfo[node]);
6020 static struct mem_cgroup *mem_cgroup_alloc(void)
6022 struct mem_cgroup *memcg;
6025 size = sizeof(struct mem_cgroup);
6026 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
6028 memcg = kzalloc(size, GFP_KERNEL);
6032 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
6035 spin_lock_init(&memcg->pcp_counter_lock);
6044 * At destroying mem_cgroup, references from swap_cgroup can remain.
6045 * (scanning all at force_empty is too costly...)
6047 * Instead of clearing all references at force_empty, we remember
6048 * the number of reference from swap_cgroup and free mem_cgroup when
6049 * it goes down to 0.
6051 * Removal of cgroup itself succeeds regardless of refs from swap.
6054 static void __mem_cgroup_free(struct mem_cgroup *memcg)
6058 mem_cgroup_remove_from_trees(memcg);
6061 free_mem_cgroup_per_zone_info(memcg, node);
6063 free_percpu(memcg->stat);
6066 * We need to make sure that (at least for now), the jump label
6067 * destruction code runs outside of the cgroup lock. This is because
6068 * get_online_cpus(), which is called from the static_branch update,
6069 * can't be called inside the cgroup_lock. cpusets are the ones
6070 * enforcing this dependency, so if they ever change, we might as well.
6072 * schedule_work() will guarantee this happens. Be careful if you need
6073 * to move this code around, and make sure it is outside
6076 disarm_static_keys(memcg);
6081 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6083 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
6085 if (!memcg->res.parent)
6087 return mem_cgroup_from_res_counter(memcg->res.parent, res);
6089 EXPORT_SYMBOL(parent_mem_cgroup);
6091 static void __init mem_cgroup_soft_limit_tree_init(void)
6093 struct mem_cgroup_tree_per_node *rtpn;
6094 struct mem_cgroup_tree_per_zone *rtpz;
6095 int tmp, node, zone;
6097 for_each_node(node) {
6099 if (!node_state(node, N_NORMAL_MEMORY))
6101 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
6104 soft_limit_tree.rb_tree_per_node[node] = rtpn;
6106 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
6107 rtpz = &rtpn->rb_tree_per_zone[zone];
6108 rtpz->rb_root = RB_ROOT;
6109 spin_lock_init(&rtpz->lock);
6114 static struct cgroup_subsys_state * __ref
6115 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
6117 struct mem_cgroup *memcg;
6118 long error = -ENOMEM;
6121 memcg = mem_cgroup_alloc();
6123 return ERR_PTR(error);
6126 if (alloc_mem_cgroup_per_zone_info(memcg, node))
6130 if (parent_css == NULL) {
6131 root_mem_cgroup = memcg;
6132 res_counter_init(&memcg->res, NULL);
6133 res_counter_init(&memcg->memsw, NULL);
6134 res_counter_init(&memcg->kmem, NULL);
6137 memcg->last_scanned_node = MAX_NUMNODES;
6138 INIT_LIST_HEAD(&memcg->oom_notify);
6139 memcg->move_charge_at_immigrate = 0;
6140 mutex_init(&memcg->thresholds_lock);
6141 spin_lock_init(&memcg->move_lock);
6142 vmpressure_init(&memcg->vmpressure);
6143 INIT_LIST_HEAD(&memcg->event_list);
6144 spin_lock_init(&memcg->event_list_lock);
6149 __mem_cgroup_free(memcg);
6150 return ERR_PTR(error);
6154 mem_cgroup_css_online(struct cgroup_subsys_state *css)
6156 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6157 struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
6159 if (css->id > MEM_CGROUP_ID_MAX)
6165 mutex_lock(&memcg_create_mutex);
6167 memcg->use_hierarchy = parent->use_hierarchy;
6168 memcg->oom_kill_disable = parent->oom_kill_disable;
6169 memcg->swappiness = mem_cgroup_swappiness(parent);
6171 if (parent->use_hierarchy) {
6172 res_counter_init(&memcg->res, &parent->res);
6173 res_counter_init(&memcg->memsw, &parent->memsw);
6174 res_counter_init(&memcg->kmem, &parent->kmem);
6177 * No need to take a reference to the parent because cgroup
6178 * core guarantees its existence.
6181 res_counter_init(&memcg->res, &root_mem_cgroup->res);
6182 res_counter_init(&memcg->memsw, &root_mem_cgroup->memsw);
6183 res_counter_init(&memcg->kmem, &root_mem_cgroup->kmem);
6185 * Deeper hierachy with use_hierarchy == false doesn't make
6186 * much sense so let cgroup subsystem know about this
6187 * unfortunate state in our controller.
6189 if (parent != root_mem_cgroup)
6190 memory_cgrp_subsys.broken_hierarchy = true;
6192 mutex_unlock(&memcg_create_mutex);
6194 return memcg_init_kmem(memcg, &memory_cgrp_subsys);
6198 * Announce all parents that a group from their hierarchy is gone.
6200 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup *memcg)
6202 struct mem_cgroup *parent = memcg;
6204 while ((parent = parent_mem_cgroup(parent)))
6205 mem_cgroup_iter_invalidate(parent);
6208 * if the root memcg is not hierarchical we have to check it
6211 if (!root_mem_cgroup->use_hierarchy)
6212 mem_cgroup_iter_invalidate(root_mem_cgroup);
6215 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
6217 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6218 struct mem_cgroup_event *event, *tmp;
6219 struct cgroup_subsys_state *iter;
6222 * Unregister events and notify userspace.
6223 * Notify userspace about cgroup removing only after rmdir of cgroup
6224 * directory to avoid race between userspace and kernelspace.
6226 spin_lock(&memcg->event_list_lock);
6227 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
6228 list_del_init(&event->list);
6229 schedule_work(&event->remove);
6231 spin_unlock(&memcg->event_list_lock);
6233 kmem_cgroup_css_offline(memcg);
6235 mem_cgroup_invalidate_reclaim_iterators(memcg);
6238 * This requires that offlining is serialized. Right now that is
6239 * guaranteed because css_killed_work_fn() holds the cgroup_mutex.
6241 css_for_each_descendant_post(iter, css)
6242 mem_cgroup_reparent_charges(mem_cgroup_from_css(iter));
6244 memcg_unregister_all_caches(memcg);
6245 vmpressure_cleanup(&memcg->vmpressure);
6248 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
6250 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6252 * XXX: css_offline() would be where we should reparent all
6253 * memory to prepare the cgroup for destruction. However,
6254 * memcg does not do css_tryget_online() and res_counter charging
6255 * under the same RCU lock region, which means that charging
6256 * could race with offlining. Offlining only happens to
6257 * cgroups with no tasks in them but charges can show up
6258 * without any tasks from the swapin path when the target
6259 * memcg is looked up from the swapout record and not from the
6260 * current task as it usually is. A race like this can leak
6261 * charges and put pages with stale cgroup pointers into
6265 * lookup_swap_cgroup_id()
6267 * mem_cgroup_lookup()
6268 * css_tryget_online()
6270 * disable css_tryget_online()
6273 * reparent_charges()
6274 * res_counter_charge()
6277 * pc->mem_cgroup = dead memcg
6280 * The bulk of the charges are still moved in offline_css() to
6281 * avoid pinning a lot of pages in case a long-term reference
6282 * like a swapout record is deferring the css_free() to long
6283 * after offlining. But this makes sure we catch any charges
6284 * made after offlining:
6286 mem_cgroup_reparent_charges(memcg);
6288 memcg_destroy_kmem(memcg);
6289 __mem_cgroup_free(memcg);
6293 * mem_cgroup_css_reset - reset the states of a mem_cgroup
6294 * @css: the target css
6296 * Reset the states of the mem_cgroup associated with @css. This is
6297 * invoked when the userland requests disabling on the default hierarchy
6298 * but the memcg is pinned through dependency. The memcg should stop
6299 * applying policies and should revert to the vanilla state as it may be
6300 * made visible again.
6302 * The current implementation only resets the essential configurations.
6303 * This needs to be expanded to cover all the visible parts.
6305 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
6307 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6309 mem_cgroup_resize_limit(memcg, ULLONG_MAX);
6310 mem_cgroup_resize_memsw_limit(memcg, ULLONG_MAX);
6311 memcg_update_kmem_limit(memcg, ULLONG_MAX);
6312 res_counter_set_soft_limit(&memcg->res, ULLONG_MAX);
6316 /* Handlers for move charge at task migration. */
6317 static int mem_cgroup_do_precharge(unsigned long count)
6321 /* Try a single bulk charge without reclaim first */
6322 ret = mem_cgroup_try_charge(mc.to, GFP_KERNEL & ~__GFP_WAIT, count);
6324 mc.precharge += count;
6327 if (ret == -EINTR) {
6328 __mem_cgroup_cancel_charge(root_mem_cgroup, count);
6332 /* Try charges one by one with reclaim */
6334 ret = mem_cgroup_try_charge(mc.to,
6335 GFP_KERNEL & ~__GFP_NORETRY, 1);
6337 * In case of failure, any residual charges against
6338 * mc.to will be dropped by mem_cgroup_clear_mc()
6339 * later on. However, cancel any charges that are
6340 * bypassed to root right away or they'll be lost.
6343 __mem_cgroup_cancel_charge(root_mem_cgroup, 1);
6353 * get_mctgt_type - get target type of moving charge
6354 * @vma: the vma the pte to be checked belongs
6355 * @addr: the address corresponding to the pte to be checked
6356 * @ptent: the pte to be checked
6357 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6360 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6361 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6362 * move charge. if @target is not NULL, the page is stored in target->page
6363 * with extra refcnt got(Callers should handle it).
6364 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6365 * target for charge migration. if @target is not NULL, the entry is stored
6368 * Called with pte lock held.
6375 enum mc_target_type {
6381 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
6382 unsigned long addr, pte_t ptent)
6384 struct page *page = vm_normal_page(vma, addr, ptent);
6386 if (!page || !page_mapped(page))
6388 if (PageAnon(page)) {
6389 /* we don't move shared anon */
6392 } else if (!move_file())
6393 /* we ignore mapcount for file pages */
6395 if (!get_page_unless_zero(page))
6402 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6403 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6405 struct page *page = NULL;
6406 swp_entry_t ent = pte_to_swp_entry(ptent);
6408 if (!move_anon() || non_swap_entry(ent))
6411 * Because lookup_swap_cache() updates some statistics counter,
6412 * we call find_get_page() with swapper_space directly.
6414 page = find_get_page(swap_address_space(ent), ent.val);
6415 if (do_swap_account)
6416 entry->val = ent.val;
6421 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
6422 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6428 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
6429 unsigned long addr, pte_t ptent, swp_entry_t *entry)
6431 struct page *page = NULL;
6432 struct address_space *mapping;
6435 if (!vma->vm_file) /* anonymous vma */
6440 mapping = vma->vm_file->f_mapping;
6441 if (pte_none(ptent))
6442 pgoff = linear_page_index(vma, addr);
6443 else /* pte_file(ptent) is true */
6444 pgoff = pte_to_pgoff(ptent);
6446 /* page is moved even if it's not RSS of this task(page-faulted). */
6448 /* shmem/tmpfs may report page out on swap: account for that too. */
6449 if (shmem_mapping(mapping)) {
6450 page = find_get_entry(mapping, pgoff);
6451 if (radix_tree_exceptional_entry(page)) {
6452 swp_entry_t swp = radix_to_swp_entry(page);
6453 if (do_swap_account)
6455 page = find_get_page(swap_address_space(swp), swp.val);
6458 page = find_get_page(mapping, pgoff);
6460 page = find_get_page(mapping, pgoff);
6465 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
6466 unsigned long addr, pte_t ptent, union mc_target *target)
6468 struct page *page = NULL;
6469 struct page_cgroup *pc;
6470 enum mc_target_type ret = MC_TARGET_NONE;
6471 swp_entry_t ent = { .val = 0 };
6473 if (pte_present(ptent))
6474 page = mc_handle_present_pte(vma, addr, ptent);
6475 else if (is_swap_pte(ptent))
6476 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
6477 else if (pte_none(ptent) || pte_file(ptent))
6478 page = mc_handle_file_pte(vma, addr, ptent, &ent);
6480 if (!page && !ent.val)
6483 pc = lookup_page_cgroup(page);
6485 * Do only loose check w/o page_cgroup lock.
6486 * mem_cgroup_move_account() checks the pc is valid or not under
6489 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6490 ret = MC_TARGET_PAGE;
6492 target->page = page;
6494 if (!ret || !target)
6497 /* There is a swap entry and a page doesn't exist or isn't charged */
6498 if (ent.val && !ret &&
6499 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
6500 ret = MC_TARGET_SWAP;
6507 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6509 * We don't consider swapping or file mapped pages because THP does not
6510 * support them for now.
6511 * Caller should make sure that pmd_trans_huge(pmd) is true.
6513 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6514 unsigned long addr, pmd_t pmd, union mc_target *target)
6516 struct page *page = NULL;
6517 struct page_cgroup *pc;
6518 enum mc_target_type ret = MC_TARGET_NONE;
6520 page = pmd_page(pmd);
6521 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
6524 pc = lookup_page_cgroup(page);
6525 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
6526 ret = MC_TARGET_PAGE;
6529 target->page = page;
6535 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
6536 unsigned long addr, pmd_t pmd, union mc_target *target)
6538 return MC_TARGET_NONE;
6542 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
6543 unsigned long addr, unsigned long end,
6544 struct mm_walk *walk)
6546 struct vm_area_struct *vma = walk->private;
6550 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
6551 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
6552 mc.precharge += HPAGE_PMD_NR;
6557 if (pmd_trans_unstable(pmd))
6559 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6560 for (; addr != end; pte++, addr += PAGE_SIZE)
6561 if (get_mctgt_type(vma, addr, *pte, NULL))
6562 mc.precharge++; /* increment precharge temporarily */
6563 pte_unmap_unlock(pte - 1, ptl);
6569 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
6571 unsigned long precharge;
6572 struct vm_area_struct *vma;
6574 down_read(&mm->mmap_sem);
6575 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6576 struct mm_walk mem_cgroup_count_precharge_walk = {
6577 .pmd_entry = mem_cgroup_count_precharge_pte_range,
6581 if (is_vm_hugetlb_page(vma))
6583 walk_page_range(vma->vm_start, vma->vm_end,
6584 &mem_cgroup_count_precharge_walk);
6586 up_read(&mm->mmap_sem);
6588 precharge = mc.precharge;
6594 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
6596 unsigned long precharge = mem_cgroup_count_precharge(mm);
6598 VM_BUG_ON(mc.moving_task);
6599 mc.moving_task = current;
6600 return mem_cgroup_do_precharge(precharge);
6603 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6604 static void __mem_cgroup_clear_mc(void)
6606 struct mem_cgroup *from = mc.from;
6607 struct mem_cgroup *to = mc.to;
6610 /* we must uncharge all the leftover precharges from mc.to */
6612 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
6616 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6617 * we must uncharge here.
6619 if (mc.moved_charge) {
6620 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
6621 mc.moved_charge = 0;
6623 /* we must fixup refcnts and charges */
6624 if (mc.moved_swap) {
6625 /* uncharge swap account from the old cgroup */
6626 res_counter_uncharge(&mc.from->memsw,
6627 PAGE_SIZE * mc.moved_swap);
6629 for (i = 0; i < mc.moved_swap; i++)
6630 css_put(&mc.from->css);
6633 * we charged both to->res and to->memsw, so we should
6636 res_counter_uncharge(&mc.to->res,
6637 PAGE_SIZE * mc.moved_swap);
6638 /* we've already done css_get(mc.to) */
6641 memcg_oom_recover(from);
6642 memcg_oom_recover(to);
6643 wake_up_all(&mc.waitq);
6646 static void mem_cgroup_clear_mc(void)
6648 struct mem_cgroup *from = mc.from;
6651 * we must clear moving_task before waking up waiters at the end of
6654 mc.moving_task = NULL;
6655 __mem_cgroup_clear_mc();
6656 spin_lock(&mc.lock);
6659 spin_unlock(&mc.lock);
6660 mem_cgroup_end_move(from);
6663 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6664 struct cgroup_taskset *tset)
6666 struct task_struct *p = cgroup_taskset_first(tset);
6668 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6669 unsigned long move_charge_at_immigrate;
6672 * We are now commited to this value whatever it is. Changes in this
6673 * tunable will only affect upcoming migrations, not the current one.
6674 * So we need to save it, and keep it going.
6676 move_charge_at_immigrate = memcg->move_charge_at_immigrate;
6677 if (move_charge_at_immigrate) {
6678 struct mm_struct *mm;
6679 struct mem_cgroup *from = mem_cgroup_from_task(p);
6681 VM_BUG_ON(from == memcg);
6683 mm = get_task_mm(p);
6686 /* We move charges only when we move a owner of the mm */
6687 if (mm->owner == p) {
6690 VM_BUG_ON(mc.precharge);
6691 VM_BUG_ON(mc.moved_charge);
6692 VM_BUG_ON(mc.moved_swap);
6693 mem_cgroup_start_move(from);
6694 spin_lock(&mc.lock);
6697 mc.immigrate_flags = move_charge_at_immigrate;
6698 spin_unlock(&mc.lock);
6699 /* We set mc.moving_task later */
6701 ret = mem_cgroup_precharge_mc(mm);
6703 mem_cgroup_clear_mc();
6710 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6711 struct cgroup_taskset *tset)
6713 mem_cgroup_clear_mc();
6716 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
6717 unsigned long addr, unsigned long end,
6718 struct mm_walk *walk)
6721 struct vm_area_struct *vma = walk->private;
6724 enum mc_target_type target_type;
6725 union mc_target target;
6727 struct page_cgroup *pc;
6730 * We don't take compound_lock() here but no race with splitting thp
6732 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6733 * under splitting, which means there's no concurrent thp split,
6734 * - if another thread runs into split_huge_page() just after we
6735 * entered this if-block, the thread must wait for page table lock
6736 * to be unlocked in __split_huge_page_splitting(), where the main
6737 * part of thp split is not executed yet.
6739 if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
6740 if (mc.precharge < HPAGE_PMD_NR) {
6744 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
6745 if (target_type == MC_TARGET_PAGE) {
6747 if (!isolate_lru_page(page)) {
6748 pc = lookup_page_cgroup(page);
6749 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
6750 pc, mc.from, mc.to)) {
6751 mc.precharge -= HPAGE_PMD_NR;
6752 mc.moved_charge += HPAGE_PMD_NR;
6754 putback_lru_page(page);
6762 if (pmd_trans_unstable(pmd))
6765 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
6766 for (; addr != end; addr += PAGE_SIZE) {
6767 pte_t ptent = *(pte++);
6773 switch (get_mctgt_type(vma, addr, ptent, &target)) {
6774 case MC_TARGET_PAGE:
6776 if (isolate_lru_page(page))
6778 pc = lookup_page_cgroup(page);
6779 if (!mem_cgroup_move_account(page, 1, pc,
6782 /* we uncharge from mc.from later. */
6785 putback_lru_page(page);
6786 put: /* get_mctgt_type() gets the page */
6789 case MC_TARGET_SWAP:
6791 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
6793 /* we fixup refcnts and charges later. */
6801 pte_unmap_unlock(pte - 1, ptl);
6806 * We have consumed all precharges we got in can_attach().
6807 * We try charge one by one, but don't do any additional
6808 * charges to mc.to if we have failed in charge once in attach()
6811 ret = mem_cgroup_do_precharge(1);
6819 static void mem_cgroup_move_charge(struct mm_struct *mm)
6821 struct vm_area_struct *vma;
6823 lru_add_drain_all();
6825 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
6827 * Someone who are holding the mmap_sem might be waiting in
6828 * waitq. So we cancel all extra charges, wake up all waiters,
6829 * and retry. Because we cancel precharges, we might not be able
6830 * to move enough charges, but moving charge is a best-effort
6831 * feature anyway, so it wouldn't be a big problem.
6833 __mem_cgroup_clear_mc();
6837 for (vma = mm->mmap; vma; vma = vma->vm_next) {
6839 struct mm_walk mem_cgroup_move_charge_walk = {
6840 .pmd_entry = mem_cgroup_move_charge_pte_range,
6844 if (is_vm_hugetlb_page(vma))
6846 ret = walk_page_range(vma->vm_start, vma->vm_end,
6847 &mem_cgroup_move_charge_walk);
6850 * means we have consumed all precharges and failed in
6851 * doing additional charge. Just abandon here.
6855 up_read(&mm->mmap_sem);
6858 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6859 struct cgroup_taskset *tset)
6861 struct task_struct *p = cgroup_taskset_first(tset);
6862 struct mm_struct *mm = get_task_mm(p);
6866 mem_cgroup_move_charge(mm);
6870 mem_cgroup_clear_mc();
6872 #else /* !CONFIG_MMU */
6873 static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
6874 struct cgroup_taskset *tset)
6878 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
6879 struct cgroup_taskset *tset)
6882 static void mem_cgroup_move_task(struct cgroup_subsys_state *css,
6883 struct cgroup_taskset *tset)
6889 * Cgroup retains root cgroups across [un]mount cycles making it necessary
6890 * to verify whether we're attached to the default hierarchy on each mount
6893 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
6896 * use_hierarchy is forced on the default hierarchy. cgroup core
6897 * guarantees that @root doesn't have any children, so turning it
6898 * on for the root memcg is enough.
6900 if (cgroup_on_dfl(root_css->cgroup))
6901 mem_cgroup_from_css(root_css)->use_hierarchy = true;
6904 struct cgroup_subsys memory_cgrp_subsys = {
6905 .css_alloc = mem_cgroup_css_alloc,
6906 .css_online = mem_cgroup_css_online,
6907 .css_offline = mem_cgroup_css_offline,
6908 .css_free = mem_cgroup_css_free,
6909 .css_reset = mem_cgroup_css_reset,
6910 .can_attach = mem_cgroup_can_attach,
6911 .cancel_attach = mem_cgroup_cancel_attach,
6912 .attach = mem_cgroup_move_task,
6913 .bind = mem_cgroup_bind,
6914 .legacy_cftypes = mem_cgroup_files,
6918 #ifdef CONFIG_MEMCG_SWAP
6919 static int __init enable_swap_account(char *s)
6921 if (!strcmp(s, "1"))
6922 really_do_swap_account = 1;
6923 else if (!strcmp(s, "0"))
6924 really_do_swap_account = 0;
6927 __setup("swapaccount=", enable_swap_account);
6929 static void __init memsw_file_init(void)
6931 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
6932 memsw_cgroup_files));
6935 static void __init enable_swap_cgroup(void)
6937 if (!mem_cgroup_disabled() && really_do_swap_account) {
6938 do_swap_account = 1;
6944 static void __init enable_swap_cgroup(void)
6950 * subsys_initcall() for memory controller.
6952 * Some parts like hotcpu_notifier() have to be initialized from this context
6953 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6954 * everything that doesn't depend on a specific mem_cgroup structure should
6955 * be initialized from here.
6957 static int __init mem_cgroup_init(void)
6959 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
6960 enable_swap_cgroup();
6961 mem_cgroup_soft_limit_tree_init();
6965 subsys_initcall(mem_cgroup_init);