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 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/export.h>
37 #include <linux/mutex.h>
38 #include <linux/rbtree.h>
39 #include <linux/slab.h>
40 #include <linux/swap.h>
41 #include <linux/swapops.h>
42 #include <linux/spinlock.h>
43 #include <linux/eventfd.h>
44 #include <linux/sort.h>
46 #include <linux/seq_file.h>
47 #include <linux/vmalloc.h>
48 #include <linux/mm_inline.h>
49 #include <linux/page_cgroup.h>
50 #include <linux/cpu.h>
51 #include <linux/oom.h>
54 #include <net/tcp_memcontrol.h>
56 #include <asm/uaccess.h>
58 #include <trace/events/vmscan.h>
60 struct cgroup_subsys mem_cgroup_subsys __read_mostly;
61 #define MEM_CGROUP_RECLAIM_RETRIES 5
62 static struct mem_cgroup *root_mem_cgroup __read_mostly;
64 #ifdef CONFIG_MEMCG_SWAP
65 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
66 int do_swap_account __read_mostly;
68 /* for remember boot option*/
69 #ifdef CONFIG_MEMCG_SWAP_ENABLED
70 static int really_do_swap_account __initdata = 1;
72 static int really_do_swap_account __initdata = 0;
76 #define do_swap_account 0
81 * Statistics for memory cgroup.
83 enum mem_cgroup_stat_index {
85 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
87 MEM_CGROUP_STAT_CACHE, /* # of pages charged as cache */
88 MEM_CGROUP_STAT_RSS, /* # of pages charged as anon rss */
89 MEM_CGROUP_STAT_FILE_MAPPED, /* # of pages charged as file rss */
90 MEM_CGROUP_STAT_SWAP, /* # of pages, swapped out */
91 MEM_CGROUP_STAT_NSTATS,
94 static const char * const mem_cgroup_stat_names[] = {
101 enum mem_cgroup_events_index {
102 MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
103 MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
104 MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
105 MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
106 MEM_CGROUP_EVENTS_NSTATS,
109 static const char * const mem_cgroup_events_names[] = {
117 * Per memcg event counter is incremented at every pagein/pageout. With THP,
118 * it will be incremated by the number of pages. This counter is used for
119 * for trigger some periodic events. This is straightforward and better
120 * than using jiffies etc. to handle periodic memcg event.
122 enum mem_cgroup_events_target {
123 MEM_CGROUP_TARGET_THRESH,
124 MEM_CGROUP_TARGET_SOFTLIMIT,
125 MEM_CGROUP_TARGET_NUMAINFO,
128 #define THRESHOLDS_EVENTS_TARGET 128
129 #define SOFTLIMIT_EVENTS_TARGET 1024
130 #define NUMAINFO_EVENTS_TARGET 1024
132 struct mem_cgroup_stat_cpu {
133 long count[MEM_CGROUP_STAT_NSTATS];
134 unsigned long events[MEM_CGROUP_EVENTS_NSTATS];
135 unsigned long nr_page_events;
136 unsigned long targets[MEM_CGROUP_NTARGETS];
139 struct mem_cgroup_reclaim_iter {
140 /* css_id of the last scanned hierarchy member */
142 /* scan generation, increased every round-trip */
143 unsigned int generation;
147 * per-zone information in memory controller.
149 struct mem_cgroup_per_zone {
150 struct lruvec lruvec;
151 unsigned long lru_size[NR_LRU_LISTS];
153 struct mem_cgroup_reclaim_iter reclaim_iter[DEF_PRIORITY + 1];
155 struct rb_node tree_node; /* RB tree node */
156 unsigned long long usage_in_excess;/* Set to the value by which */
157 /* the soft limit is exceeded*/
159 struct mem_cgroup *memcg; /* Back pointer, we cannot */
160 /* use container_of */
163 struct mem_cgroup_per_node {
164 struct mem_cgroup_per_zone zoneinfo[MAX_NR_ZONES];
167 struct mem_cgroup_lru_info {
168 struct mem_cgroup_per_node *nodeinfo[MAX_NUMNODES];
172 * Cgroups above their limits are maintained in a RB-Tree, independent of
173 * their hierarchy representation
176 struct mem_cgroup_tree_per_zone {
177 struct rb_root rb_root;
181 struct mem_cgroup_tree_per_node {
182 struct mem_cgroup_tree_per_zone rb_tree_per_zone[MAX_NR_ZONES];
185 struct mem_cgroup_tree {
186 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
189 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
191 struct mem_cgroup_threshold {
192 struct eventfd_ctx *eventfd;
197 struct mem_cgroup_threshold_ary {
198 /* An array index points to threshold just below or equal to usage. */
199 int current_threshold;
200 /* Size of entries[] */
202 /* Array of thresholds */
203 struct mem_cgroup_threshold entries[0];
206 struct mem_cgroup_thresholds {
207 /* Primary thresholds array */
208 struct mem_cgroup_threshold_ary *primary;
210 * Spare threshold array.
211 * This is needed to make mem_cgroup_unregister_event() "never fail".
212 * It must be able to store at least primary->size - 1 entries.
214 struct mem_cgroup_threshold_ary *spare;
218 struct mem_cgroup_eventfd_list {
219 struct list_head list;
220 struct eventfd_ctx *eventfd;
223 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
224 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
227 * The memory controller data structure. The memory controller controls both
228 * page cache and RSS per cgroup. We would eventually like to provide
229 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
230 * to help the administrator determine what knobs to tune.
232 * TODO: Add a water mark for the memory controller. Reclaim will begin when
233 * we hit the water mark. May be even add a low water mark, such that
234 * no reclaim occurs from a cgroup at it's low water mark, this is
235 * a feature that will be implemented much later in the future.
238 struct cgroup_subsys_state css;
240 * the counter to account for memory usage
242 struct res_counter res;
246 * the counter to account for mem+swap usage.
248 struct res_counter memsw;
251 * rcu_freeing is used only when freeing struct mem_cgroup,
252 * so put it into a union to avoid wasting more memory.
253 * It must be disjoint from the css field. It could be
254 * in a union with the res field, but res plays a much
255 * larger part in mem_cgroup life than memsw, and might
256 * be of interest, even at time of free, when debugging.
257 * So share rcu_head with the less interesting memsw.
259 struct rcu_head rcu_freeing;
261 * We also need some space for a worker in deferred freeing.
262 * By the time we call it, rcu_freeing is no longer in use.
264 struct work_struct work_freeing;
268 * Per cgroup active and inactive list, similar to the
269 * per zone LRU lists.
271 struct mem_cgroup_lru_info info;
272 int last_scanned_node;
274 nodemask_t scan_nodes;
275 atomic_t numainfo_events;
276 atomic_t numainfo_updating;
279 * Should the accounting and control be hierarchical, per subtree?
289 /* OOM-Killer disable */
290 int oom_kill_disable;
292 /* set when res.limit == memsw.limit */
293 bool memsw_is_minimum;
295 /* protect arrays of thresholds */
296 struct mutex thresholds_lock;
298 /* thresholds for memory usage. RCU-protected */
299 struct mem_cgroup_thresholds thresholds;
301 /* thresholds for mem+swap usage. RCU-protected */
302 struct mem_cgroup_thresholds memsw_thresholds;
304 /* For oom notifier event fd */
305 struct list_head oom_notify;
308 * Should we move charges of a task when a task is moved into this
309 * mem_cgroup ? And what type of charges should we move ?
311 unsigned long move_charge_at_immigrate;
313 * set > 0 if pages under this cgroup are moving to other cgroup.
315 atomic_t moving_account;
316 /* taken only while moving_account > 0 */
317 spinlock_t move_lock;
321 struct mem_cgroup_stat_cpu __percpu *stat;
323 * used when a cpu is offlined or other synchronizations
324 * See mem_cgroup_read_stat().
326 struct mem_cgroup_stat_cpu nocpu_base;
327 spinlock_t pcp_counter_lock;
330 struct tcp_memcontrol tcp_mem;
334 /* Stuffs for move charges at task migration. */
336 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
337 * left-shifted bitmap of these types.
340 MOVE_CHARGE_TYPE_ANON, /* private anonymous page and swap of it */
341 MOVE_CHARGE_TYPE_FILE, /* file page(including tmpfs) and swap of it */
345 /* "mc" and its members are protected by cgroup_mutex */
346 static struct move_charge_struct {
347 spinlock_t lock; /* for from, to */
348 struct mem_cgroup *from;
349 struct mem_cgroup *to;
350 unsigned long precharge;
351 unsigned long moved_charge;
352 unsigned long moved_swap;
353 struct task_struct *moving_task; /* a task moving charges */
354 wait_queue_head_t waitq; /* a waitq for other context */
356 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
357 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
360 static bool move_anon(void)
362 return test_bit(MOVE_CHARGE_TYPE_ANON,
363 &mc.to->move_charge_at_immigrate);
366 static bool move_file(void)
368 return test_bit(MOVE_CHARGE_TYPE_FILE,
369 &mc.to->move_charge_at_immigrate);
373 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
374 * limit reclaim to prevent infinite loops, if they ever occur.
376 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
377 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
380 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
381 MEM_CGROUP_CHARGE_TYPE_ANON,
382 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
383 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
384 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
388 /* for encoding cft->private value on file */
391 #define _OOM_TYPE (2)
392 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
393 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
394 #define MEMFILE_ATTR(val) ((val) & 0xffff)
395 /* Used for OOM nofiier */
396 #define OOM_CONTROL (0)
399 * Reclaim flags for mem_cgroup_hierarchical_reclaim
401 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
402 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
403 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
404 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
406 static void mem_cgroup_get(struct mem_cgroup *memcg);
407 static void mem_cgroup_put(struct mem_cgroup *memcg);
409 /* Writing them here to avoid exposing memcg's inner layout */
410 #ifdef CONFIG_MEMCG_KMEM
411 #include <net/sock.h>
414 static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
415 void sock_update_memcg(struct sock *sk)
417 if (mem_cgroup_sockets_enabled) {
418 struct mem_cgroup *memcg;
419 struct cg_proto *cg_proto;
421 BUG_ON(!sk->sk_prot->proto_cgroup);
423 /* Socket cloning can throw us here with sk_cgrp already
424 * filled. It won't however, necessarily happen from
425 * process context. So the test for root memcg given
426 * the current task's memcg won't help us in this case.
428 * Respecting the original socket's memcg is a better
429 * decision in this case.
432 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
433 mem_cgroup_get(sk->sk_cgrp->memcg);
438 memcg = mem_cgroup_from_task(current);
439 cg_proto = sk->sk_prot->proto_cgroup(memcg);
440 if (!mem_cgroup_is_root(memcg) && memcg_proto_active(cg_proto)) {
441 mem_cgroup_get(memcg);
442 sk->sk_cgrp = cg_proto;
447 EXPORT_SYMBOL(sock_update_memcg);
449 void sock_release_memcg(struct sock *sk)
451 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
452 struct mem_cgroup *memcg;
453 WARN_ON(!sk->sk_cgrp->memcg);
454 memcg = sk->sk_cgrp->memcg;
455 mem_cgroup_put(memcg);
460 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
462 if (!memcg || mem_cgroup_is_root(memcg))
465 return &memcg->tcp_mem.cg_proto;
467 EXPORT_SYMBOL(tcp_proto_cgroup);
468 #endif /* CONFIG_INET */
469 #endif /* CONFIG_MEMCG_KMEM */
471 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
472 static void disarm_sock_keys(struct mem_cgroup *memcg)
474 if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto))
476 static_key_slow_dec(&memcg_socket_limit_enabled);
479 static void disarm_sock_keys(struct mem_cgroup *memcg)
484 static void drain_all_stock_async(struct mem_cgroup *memcg);
486 static struct mem_cgroup_per_zone *
487 mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
489 return &memcg->info.nodeinfo[nid]->zoneinfo[zid];
492 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
497 static struct mem_cgroup_per_zone *
498 page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
500 int nid = page_to_nid(page);
501 int zid = page_zonenum(page);
503 return mem_cgroup_zoneinfo(memcg, nid, zid);
506 static struct mem_cgroup_tree_per_zone *
507 soft_limit_tree_node_zone(int nid, int zid)
509 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
512 static struct mem_cgroup_tree_per_zone *
513 soft_limit_tree_from_page(struct page *page)
515 int nid = page_to_nid(page);
516 int zid = page_zonenum(page);
518 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
522 __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
523 struct mem_cgroup_per_zone *mz,
524 struct mem_cgroup_tree_per_zone *mctz,
525 unsigned long long new_usage_in_excess)
527 struct rb_node **p = &mctz->rb_root.rb_node;
528 struct rb_node *parent = NULL;
529 struct mem_cgroup_per_zone *mz_node;
534 mz->usage_in_excess = new_usage_in_excess;
535 if (!mz->usage_in_excess)
539 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
541 if (mz->usage_in_excess < mz_node->usage_in_excess)
544 * We can't avoid mem cgroups that are over their soft
545 * limit by the same amount
547 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
550 rb_link_node(&mz->tree_node, parent, p);
551 rb_insert_color(&mz->tree_node, &mctz->rb_root);
556 __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
557 struct mem_cgroup_per_zone *mz,
558 struct mem_cgroup_tree_per_zone *mctz)
562 rb_erase(&mz->tree_node, &mctz->rb_root);
567 mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
568 struct mem_cgroup_per_zone *mz,
569 struct mem_cgroup_tree_per_zone *mctz)
571 spin_lock(&mctz->lock);
572 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
573 spin_unlock(&mctz->lock);
577 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
579 unsigned long long excess;
580 struct mem_cgroup_per_zone *mz;
581 struct mem_cgroup_tree_per_zone *mctz;
582 int nid = page_to_nid(page);
583 int zid = page_zonenum(page);
584 mctz = soft_limit_tree_from_page(page);
587 * Necessary to update all ancestors when hierarchy is used.
588 * because their event counter is not touched.
590 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
591 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
592 excess = res_counter_soft_limit_excess(&memcg->res);
594 * We have to update the tree if mz is on RB-tree or
595 * mem is over its softlimit.
597 if (excess || mz->on_tree) {
598 spin_lock(&mctz->lock);
599 /* if on-tree, remove it */
601 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
603 * Insert again. mz->usage_in_excess will be updated.
604 * If excess is 0, no tree ops.
606 __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
607 spin_unlock(&mctz->lock);
612 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
615 struct mem_cgroup_per_zone *mz;
616 struct mem_cgroup_tree_per_zone *mctz;
618 for_each_node(node) {
619 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
620 mz = mem_cgroup_zoneinfo(memcg, node, zone);
621 mctz = soft_limit_tree_node_zone(node, zone);
622 mem_cgroup_remove_exceeded(memcg, mz, mctz);
627 static struct mem_cgroup_per_zone *
628 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
630 struct rb_node *rightmost = NULL;
631 struct mem_cgroup_per_zone *mz;
635 rightmost = rb_last(&mctz->rb_root);
637 goto done; /* Nothing to reclaim from */
639 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
641 * Remove the node now but someone else can add it back,
642 * we will to add it back at the end of reclaim to its correct
643 * position in the tree.
645 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
646 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
647 !css_tryget(&mz->memcg->css))
653 static struct mem_cgroup_per_zone *
654 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
656 struct mem_cgroup_per_zone *mz;
658 spin_lock(&mctz->lock);
659 mz = __mem_cgroup_largest_soft_limit_node(mctz);
660 spin_unlock(&mctz->lock);
665 * Implementation Note: reading percpu statistics for memcg.
667 * Both of vmstat[] and percpu_counter has threshold and do periodic
668 * synchronization to implement "quick" read. There are trade-off between
669 * reading cost and precision of value. Then, we may have a chance to implement
670 * a periodic synchronizion of counter in memcg's counter.
672 * But this _read() function is used for user interface now. The user accounts
673 * memory usage by memory cgroup and he _always_ requires exact value because
674 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
675 * have to visit all online cpus and make sum. So, for now, unnecessary
676 * synchronization is not implemented. (just implemented for cpu hotplug)
678 * If there are kernel internal actions which can make use of some not-exact
679 * value, and reading all cpu value can be performance bottleneck in some
680 * common workload, threashold and synchonization as vmstat[] should be
683 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
684 enum mem_cgroup_stat_index idx)
690 for_each_online_cpu(cpu)
691 val += per_cpu(memcg->stat->count[idx], cpu);
692 #ifdef CONFIG_HOTPLUG_CPU
693 spin_lock(&memcg->pcp_counter_lock);
694 val += memcg->nocpu_base.count[idx];
695 spin_unlock(&memcg->pcp_counter_lock);
701 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
704 int val = (charge) ? 1 : -1;
705 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
708 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
709 enum mem_cgroup_events_index idx)
711 unsigned long val = 0;
714 for_each_online_cpu(cpu)
715 val += per_cpu(memcg->stat->events[idx], cpu);
716 #ifdef CONFIG_HOTPLUG_CPU
717 spin_lock(&memcg->pcp_counter_lock);
718 val += memcg->nocpu_base.events[idx];
719 spin_unlock(&memcg->pcp_counter_lock);
724 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
725 bool anon, int nr_pages)
730 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
731 * counted as CACHE even if it's on ANON LRU.
734 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
737 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
740 /* pagein of a big page is an event. So, ignore page size */
742 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
744 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
745 nr_pages = -nr_pages; /* for event */
748 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
754 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
756 struct mem_cgroup_per_zone *mz;
758 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
759 return mz->lru_size[lru];
763 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
764 unsigned int lru_mask)
766 struct mem_cgroup_per_zone *mz;
768 unsigned long ret = 0;
770 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
773 if (BIT(lru) & lru_mask)
774 ret += mz->lru_size[lru];
780 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
781 int nid, unsigned int lru_mask)
786 for (zid = 0; zid < MAX_NR_ZONES; zid++)
787 total += mem_cgroup_zone_nr_lru_pages(memcg,
793 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
794 unsigned int lru_mask)
799 for_each_node_state(nid, N_HIGH_MEMORY)
800 total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
804 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
805 enum mem_cgroup_events_target target)
807 unsigned long val, next;
809 val = __this_cpu_read(memcg->stat->nr_page_events);
810 next = __this_cpu_read(memcg->stat->targets[target]);
811 /* from time_after() in jiffies.h */
812 if ((long)next - (long)val < 0) {
814 case MEM_CGROUP_TARGET_THRESH:
815 next = val + THRESHOLDS_EVENTS_TARGET;
817 case MEM_CGROUP_TARGET_SOFTLIMIT:
818 next = val + SOFTLIMIT_EVENTS_TARGET;
820 case MEM_CGROUP_TARGET_NUMAINFO:
821 next = val + NUMAINFO_EVENTS_TARGET;
826 __this_cpu_write(memcg->stat->targets[target], next);
833 * Check events in order.
836 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
839 /* threshold event is triggered in finer grain than soft limit */
840 if (unlikely(mem_cgroup_event_ratelimit(memcg,
841 MEM_CGROUP_TARGET_THRESH))) {
843 bool do_numainfo __maybe_unused;
845 do_softlimit = mem_cgroup_event_ratelimit(memcg,
846 MEM_CGROUP_TARGET_SOFTLIMIT);
848 do_numainfo = mem_cgroup_event_ratelimit(memcg,
849 MEM_CGROUP_TARGET_NUMAINFO);
853 mem_cgroup_threshold(memcg);
854 if (unlikely(do_softlimit))
855 mem_cgroup_update_tree(memcg, page);
857 if (unlikely(do_numainfo))
858 atomic_inc(&memcg->numainfo_events);
864 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
866 return container_of(cgroup_subsys_state(cont,
867 mem_cgroup_subsys_id), struct mem_cgroup,
871 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
874 * mm_update_next_owner() may clear mm->owner to NULL
875 * if it races with swapoff, page migration, etc.
876 * So this can be called with p == NULL.
881 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
882 struct mem_cgroup, css);
885 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
887 struct mem_cgroup *memcg = NULL;
892 * Because we have no locks, mm->owner's may be being moved to other
893 * cgroup. We use css_tryget() here even if this looks
894 * pessimistic (rather than adding locks here).
898 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
899 if (unlikely(!memcg))
901 } while (!css_tryget(&memcg->css));
907 * mem_cgroup_iter - iterate over memory cgroup hierarchy
908 * @root: hierarchy root
909 * @prev: previously returned memcg, NULL on first invocation
910 * @reclaim: cookie for shared reclaim walks, NULL for full walks
912 * Returns references to children of the hierarchy below @root, or
913 * @root itself, or %NULL after a full round-trip.
915 * Caller must pass the return value in @prev on subsequent
916 * invocations for reference counting, or use mem_cgroup_iter_break()
917 * to cancel a hierarchy walk before the round-trip is complete.
919 * Reclaimers can specify a zone and a priority level in @reclaim to
920 * divide up the memcgs in the hierarchy among all concurrent
921 * reclaimers operating on the same zone and priority.
923 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
924 struct mem_cgroup *prev,
925 struct mem_cgroup_reclaim_cookie *reclaim)
927 struct mem_cgroup *memcg = NULL;
930 if (mem_cgroup_disabled())
934 root = root_mem_cgroup;
936 if (prev && !reclaim)
937 id = css_id(&prev->css);
939 if (prev && prev != root)
942 if (!root->use_hierarchy && root != root_mem_cgroup) {
949 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
950 struct cgroup_subsys_state *css;
953 int nid = zone_to_nid(reclaim->zone);
954 int zid = zone_idx(reclaim->zone);
955 struct mem_cgroup_per_zone *mz;
957 mz = mem_cgroup_zoneinfo(root, nid, zid);
958 iter = &mz->reclaim_iter[reclaim->priority];
959 if (prev && reclaim->generation != iter->generation)
965 css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
967 if (css == &root->css || css_tryget(css))
968 memcg = container_of(css,
969 struct mem_cgroup, css);
978 else if (!prev && memcg)
979 reclaim->generation = iter->generation;
989 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
990 * @root: hierarchy root
991 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
993 void mem_cgroup_iter_break(struct mem_cgroup *root,
994 struct mem_cgroup *prev)
997 root = root_mem_cgroup;
998 if (prev && prev != root)
1003 * Iteration constructs for visiting all cgroups (under a tree). If
1004 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1005 * be used for reference counting.
1007 #define for_each_mem_cgroup_tree(iter, root) \
1008 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1010 iter = mem_cgroup_iter(root, iter, NULL))
1012 #define for_each_mem_cgroup(iter) \
1013 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1015 iter = mem_cgroup_iter(NULL, iter, NULL))
1017 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
1019 return (memcg == root_mem_cgroup);
1022 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1024 struct mem_cgroup *memcg;
1030 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1031 if (unlikely(!memcg))
1036 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1039 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1047 EXPORT_SYMBOL(mem_cgroup_count_vm_event);
1050 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1051 * @zone: zone of the wanted lruvec
1052 * @memcg: memcg of the wanted lruvec
1054 * Returns the lru list vector holding pages for the given @zone and
1055 * @mem. This can be the global zone lruvec, if the memory controller
1058 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1059 struct mem_cgroup *memcg)
1061 struct mem_cgroup_per_zone *mz;
1063 if (mem_cgroup_disabled())
1064 return &zone->lruvec;
1066 mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
1071 * Following LRU functions are allowed to be used without PCG_LOCK.
1072 * Operations are called by routine of global LRU independently from memcg.
1073 * What we have to take care of here is validness of pc->mem_cgroup.
1075 * Changes to pc->mem_cgroup happens when
1078 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1079 * It is added to LRU before charge.
1080 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1081 * When moving account, the page is not on LRU. It's isolated.
1085 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1087 * @zone: zone of the page
1089 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1091 struct mem_cgroup_per_zone *mz;
1092 struct mem_cgroup *memcg;
1093 struct page_cgroup *pc;
1095 if (mem_cgroup_disabled())
1096 return &zone->lruvec;
1098 pc = lookup_page_cgroup(page);
1099 memcg = pc->mem_cgroup;
1102 * Surreptitiously switch any uncharged offlist page to root:
1103 * an uncharged page off lru does nothing to secure
1104 * its former mem_cgroup from sudden removal.
1106 * Our caller holds lru_lock, and PageCgroupUsed is updated
1107 * under page_cgroup lock: between them, they make all uses
1108 * of pc->mem_cgroup safe.
1110 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1111 pc->mem_cgroup = memcg = root_mem_cgroup;
1113 mz = page_cgroup_zoneinfo(memcg, page);
1118 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1119 * @lruvec: mem_cgroup per zone lru vector
1120 * @lru: index of lru list the page is sitting on
1121 * @nr_pages: positive when adding or negative when removing
1123 * This function must be called when a page is added to or removed from an
1126 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1129 struct mem_cgroup_per_zone *mz;
1130 unsigned long *lru_size;
1132 if (mem_cgroup_disabled())
1135 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1136 lru_size = mz->lru_size + lru;
1137 *lru_size += nr_pages;
1138 VM_BUG_ON((long)(*lru_size) < 0);
1142 * Checks whether given mem is same or in the root_mem_cgroup's
1145 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1146 struct mem_cgroup *memcg)
1148 if (root_memcg == memcg)
1150 if (!root_memcg->use_hierarchy || !memcg)
1152 return css_is_ancestor(&memcg->css, &root_memcg->css);
1155 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1156 struct mem_cgroup *memcg)
1161 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1166 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
1169 struct mem_cgroup *curr = NULL;
1170 struct task_struct *p;
1172 p = find_lock_task_mm(task);
1174 curr = try_get_mem_cgroup_from_mm(p->mm);
1178 * All threads may have already detached their mm's, but the oom
1179 * killer still needs to detect if they have already been oom
1180 * killed to prevent needlessly killing additional tasks.
1183 curr = mem_cgroup_from_task(task);
1185 css_get(&curr->css);
1191 * We should check use_hierarchy of "memcg" not "curr". Because checking
1192 * use_hierarchy of "curr" here make this function true if hierarchy is
1193 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1194 * hierarchy(even if use_hierarchy is disabled in "memcg").
1196 ret = mem_cgroup_same_or_subtree(memcg, curr);
1197 css_put(&curr->css);
1201 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1203 unsigned long inactive_ratio;
1204 unsigned long inactive;
1205 unsigned long active;
1208 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1209 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1211 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1213 inactive_ratio = int_sqrt(10 * gb);
1217 return inactive * inactive_ratio < active;
1220 int mem_cgroup_inactive_file_is_low(struct lruvec *lruvec)
1222 unsigned long active;
1223 unsigned long inactive;
1225 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_FILE);
1226 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_FILE);
1228 return (active > inactive);
1231 #define mem_cgroup_from_res_counter(counter, member) \
1232 container_of(counter, struct mem_cgroup, member)
1235 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1236 * @memcg: the memory cgroup
1238 * Returns the maximum amount of memory @mem can be charged with, in
1241 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1243 unsigned long long margin;
1245 margin = res_counter_margin(&memcg->res);
1246 if (do_swap_account)
1247 margin = min(margin, res_counter_margin(&memcg->memsw));
1248 return margin >> PAGE_SHIFT;
1251 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1253 struct cgroup *cgrp = memcg->css.cgroup;
1256 if (cgrp->parent == NULL)
1257 return vm_swappiness;
1259 return memcg->swappiness;
1263 * memcg->moving_account is used for checking possibility that some thread is
1264 * calling move_account(). When a thread on CPU-A starts moving pages under
1265 * a memcg, other threads should check memcg->moving_account under
1266 * rcu_read_lock(), like this:
1270 * memcg->moving_account+1 if (memcg->mocing_account)
1272 * synchronize_rcu() update something.
1277 /* for quick checking without looking up memcg */
1278 atomic_t memcg_moving __read_mostly;
1280 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1282 atomic_inc(&memcg_moving);
1283 atomic_inc(&memcg->moving_account);
1287 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1290 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1291 * We check NULL in callee rather than caller.
1294 atomic_dec(&memcg_moving);
1295 atomic_dec(&memcg->moving_account);
1300 * 2 routines for checking "mem" is under move_account() or not.
1302 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1303 * is used for avoiding races in accounting. If true,
1304 * pc->mem_cgroup may be overwritten.
1306 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1307 * under hierarchy of moving cgroups. This is for
1308 * waiting at hith-memory prressure caused by "move".
1311 static bool mem_cgroup_stolen(struct mem_cgroup *memcg)
1313 VM_BUG_ON(!rcu_read_lock_held());
1314 return atomic_read(&memcg->moving_account) > 0;
1317 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1319 struct mem_cgroup *from;
1320 struct mem_cgroup *to;
1323 * Unlike task_move routines, we access mc.to, mc.from not under
1324 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1326 spin_lock(&mc.lock);
1332 ret = mem_cgroup_same_or_subtree(memcg, from)
1333 || mem_cgroup_same_or_subtree(memcg, to);
1335 spin_unlock(&mc.lock);
1339 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1341 if (mc.moving_task && current != mc.moving_task) {
1342 if (mem_cgroup_under_move(memcg)) {
1344 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1345 /* moving charge context might have finished. */
1348 finish_wait(&mc.waitq, &wait);
1356 * Take this lock when
1357 * - a code tries to modify page's memcg while it's USED.
1358 * - a code tries to modify page state accounting in a memcg.
1359 * see mem_cgroup_stolen(), too.
1361 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1362 unsigned long *flags)
1364 spin_lock_irqsave(&memcg->move_lock, *flags);
1367 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1368 unsigned long *flags)
1370 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1374 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1375 * @memcg: The memory cgroup that went over limit
1376 * @p: Task that is going to be killed
1378 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1381 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1383 struct cgroup *task_cgrp;
1384 struct cgroup *mem_cgrp;
1386 * Need a buffer in BSS, can't rely on allocations. The code relies
1387 * on the assumption that OOM is serialized for memory controller.
1388 * If this assumption is broken, revisit this code.
1390 static char memcg_name[PATH_MAX];
1398 mem_cgrp = memcg->css.cgroup;
1399 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1401 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1404 * Unfortunately, we are unable to convert to a useful name
1405 * But we'll still print out the usage information
1412 printk(KERN_INFO "Task in %s killed", memcg_name);
1415 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1423 * Continues from above, so we don't need an KERN_ level
1425 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1428 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1429 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1430 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1431 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1432 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1434 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1435 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1436 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1440 * This function returns the number of memcg under hierarchy tree. Returns
1441 * 1(self count) if no children.
1443 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1446 struct mem_cgroup *iter;
1448 for_each_mem_cgroup_tree(iter, memcg)
1454 * Return the memory (and swap, if configured) limit for a memcg.
1456 static u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1461 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1462 limit += total_swap_pages << PAGE_SHIFT;
1464 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1466 * If memsw is finite and limits the amount of swap space available
1467 * to this memcg, return that limit.
1469 return min(limit, memsw);
1472 void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1475 struct mem_cgroup *iter;
1476 unsigned long chosen_points = 0;
1477 unsigned long totalpages;
1478 unsigned int points = 0;
1479 struct task_struct *chosen = NULL;
1482 * If current has a pending SIGKILL, then automatically select it. The
1483 * goal is to allow it to allocate so that it may quickly exit and free
1486 if (fatal_signal_pending(current)) {
1487 set_thread_flag(TIF_MEMDIE);
1491 check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, order, NULL);
1492 totalpages = mem_cgroup_get_limit(memcg) >> PAGE_SHIFT ? : 1;
1493 for_each_mem_cgroup_tree(iter, memcg) {
1494 struct cgroup *cgroup = iter->css.cgroup;
1495 struct cgroup_iter it;
1496 struct task_struct *task;
1498 cgroup_iter_start(cgroup, &it);
1499 while ((task = cgroup_iter_next(cgroup, &it))) {
1500 switch (oom_scan_process_thread(task, totalpages, NULL,
1502 case OOM_SCAN_SELECT:
1504 put_task_struct(chosen);
1506 chosen_points = ULONG_MAX;
1507 get_task_struct(chosen);
1509 case OOM_SCAN_CONTINUE:
1511 case OOM_SCAN_ABORT:
1512 cgroup_iter_end(cgroup, &it);
1513 mem_cgroup_iter_break(memcg, iter);
1515 put_task_struct(chosen);
1520 points = oom_badness(task, memcg, NULL, totalpages);
1521 if (points > chosen_points) {
1523 put_task_struct(chosen);
1525 chosen_points = points;
1526 get_task_struct(chosen);
1529 cgroup_iter_end(cgroup, &it);
1534 points = chosen_points * 1000 / totalpages;
1535 oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg,
1536 NULL, "Memory cgroup out of memory");
1539 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1541 unsigned long flags)
1543 unsigned long total = 0;
1544 bool noswap = false;
1547 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1549 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1552 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1554 drain_all_stock_async(memcg);
1555 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1557 * Allow limit shrinkers, which are triggered directly
1558 * by userspace, to catch signals and stop reclaim
1559 * after minimal progress, regardless of the margin.
1561 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1563 if (mem_cgroup_margin(memcg))
1566 * If nothing was reclaimed after two attempts, there
1567 * may be no reclaimable pages in this hierarchy.
1576 * test_mem_cgroup_node_reclaimable
1577 * @memcg: the target memcg
1578 * @nid: the node ID to be checked.
1579 * @noswap : specify true here if the user wants flle only information.
1581 * This function returns whether the specified memcg contains any
1582 * reclaimable pages on a node. Returns true if there are any reclaimable
1583 * pages in the node.
1585 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1586 int nid, bool noswap)
1588 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1590 if (noswap || !total_swap_pages)
1592 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1597 #if MAX_NUMNODES > 1
1600 * Always updating the nodemask is not very good - even if we have an empty
1601 * list or the wrong list here, we can start from some node and traverse all
1602 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1605 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1609 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1610 * pagein/pageout changes since the last update.
1612 if (!atomic_read(&memcg->numainfo_events))
1614 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1617 /* make a nodemask where this memcg uses memory from */
1618 memcg->scan_nodes = node_states[N_HIGH_MEMORY];
1620 for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
1622 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1623 node_clear(nid, memcg->scan_nodes);
1626 atomic_set(&memcg->numainfo_events, 0);
1627 atomic_set(&memcg->numainfo_updating, 0);
1631 * Selecting a node where we start reclaim from. Because what we need is just
1632 * reducing usage counter, start from anywhere is O,K. Considering
1633 * memory reclaim from current node, there are pros. and cons.
1635 * Freeing memory from current node means freeing memory from a node which
1636 * we'll use or we've used. So, it may make LRU bad. And if several threads
1637 * hit limits, it will see a contention on a node. But freeing from remote
1638 * node means more costs for memory reclaim because of memory latency.
1640 * Now, we use round-robin. Better algorithm is welcomed.
1642 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1646 mem_cgroup_may_update_nodemask(memcg);
1647 node = memcg->last_scanned_node;
1649 node = next_node(node, memcg->scan_nodes);
1650 if (node == MAX_NUMNODES)
1651 node = first_node(memcg->scan_nodes);
1653 * We call this when we hit limit, not when pages are added to LRU.
1654 * No LRU may hold pages because all pages are UNEVICTABLE or
1655 * memcg is too small and all pages are not on LRU. In that case,
1656 * we use curret node.
1658 if (unlikely(node == MAX_NUMNODES))
1659 node = numa_node_id();
1661 memcg->last_scanned_node = node;
1666 * Check all nodes whether it contains reclaimable pages or not.
1667 * For quick scan, we make use of scan_nodes. This will allow us to skip
1668 * unused nodes. But scan_nodes is lazily updated and may not cotain
1669 * enough new information. We need to do double check.
1671 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1676 * quick check...making use of scan_node.
1677 * We can skip unused nodes.
1679 if (!nodes_empty(memcg->scan_nodes)) {
1680 for (nid = first_node(memcg->scan_nodes);
1682 nid = next_node(nid, memcg->scan_nodes)) {
1684 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1689 * Check rest of nodes.
1691 for_each_node_state(nid, N_HIGH_MEMORY) {
1692 if (node_isset(nid, memcg->scan_nodes))
1694 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1701 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1706 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1708 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1712 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1715 unsigned long *total_scanned)
1717 struct mem_cgroup *victim = NULL;
1720 unsigned long excess;
1721 unsigned long nr_scanned;
1722 struct mem_cgroup_reclaim_cookie reclaim = {
1727 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
1730 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1735 * If we have not been able to reclaim
1736 * anything, it might because there are
1737 * no reclaimable pages under this hierarchy
1742 * We want to do more targeted reclaim.
1743 * excess >> 2 is not to excessive so as to
1744 * reclaim too much, nor too less that we keep
1745 * coming back to reclaim from this cgroup
1747 if (total >= (excess >> 2) ||
1748 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1753 if (!mem_cgroup_reclaimable(victim, false))
1755 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
1757 *total_scanned += nr_scanned;
1758 if (!res_counter_soft_limit_excess(&root_memcg->res))
1761 mem_cgroup_iter_break(root_memcg, victim);
1766 * Check OOM-Killer is already running under our hierarchy.
1767 * If someone is running, return false.
1768 * Has to be called with memcg_oom_lock
1770 static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
1772 struct mem_cgroup *iter, *failed = NULL;
1774 for_each_mem_cgroup_tree(iter, memcg) {
1775 if (iter->oom_lock) {
1777 * this subtree of our hierarchy is already locked
1778 * so we cannot give a lock.
1781 mem_cgroup_iter_break(memcg, iter);
1784 iter->oom_lock = true;
1791 * OK, we failed to lock the whole subtree so we have to clean up
1792 * what we set up to the failing subtree
1794 for_each_mem_cgroup_tree(iter, memcg) {
1795 if (iter == failed) {
1796 mem_cgroup_iter_break(memcg, iter);
1799 iter->oom_lock = false;
1805 * Has to be called with memcg_oom_lock
1807 static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1809 struct mem_cgroup *iter;
1811 for_each_mem_cgroup_tree(iter, memcg)
1812 iter->oom_lock = false;
1816 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1818 struct mem_cgroup *iter;
1820 for_each_mem_cgroup_tree(iter, memcg)
1821 atomic_inc(&iter->under_oom);
1824 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1826 struct mem_cgroup *iter;
1829 * When a new child is created while the hierarchy is under oom,
1830 * mem_cgroup_oom_lock() may not be called. We have to use
1831 * atomic_add_unless() here.
1833 for_each_mem_cgroup_tree(iter, memcg)
1834 atomic_add_unless(&iter->under_oom, -1, 0);
1837 static DEFINE_SPINLOCK(memcg_oom_lock);
1838 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1840 struct oom_wait_info {
1841 struct mem_cgroup *memcg;
1845 static int memcg_oom_wake_function(wait_queue_t *wait,
1846 unsigned mode, int sync, void *arg)
1848 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1849 struct mem_cgroup *oom_wait_memcg;
1850 struct oom_wait_info *oom_wait_info;
1852 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1853 oom_wait_memcg = oom_wait_info->memcg;
1856 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
1857 * Then we can use css_is_ancestor without taking care of RCU.
1859 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
1860 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
1862 return autoremove_wake_function(wait, mode, sync, arg);
1865 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1867 /* for filtering, pass "memcg" as argument. */
1868 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1871 static void memcg_oom_recover(struct mem_cgroup *memcg)
1873 if (memcg && atomic_read(&memcg->under_oom))
1874 memcg_wakeup_oom(memcg);
1878 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1880 static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask,
1883 struct oom_wait_info owait;
1884 bool locked, need_to_kill;
1886 owait.memcg = memcg;
1887 owait.wait.flags = 0;
1888 owait.wait.func = memcg_oom_wake_function;
1889 owait.wait.private = current;
1890 INIT_LIST_HEAD(&owait.wait.task_list);
1891 need_to_kill = true;
1892 mem_cgroup_mark_under_oom(memcg);
1894 /* At first, try to OOM lock hierarchy under memcg.*/
1895 spin_lock(&memcg_oom_lock);
1896 locked = mem_cgroup_oom_lock(memcg);
1898 * Even if signal_pending(), we can't quit charge() loop without
1899 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1900 * under OOM is always welcomed, use TASK_KILLABLE here.
1902 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1903 if (!locked || memcg->oom_kill_disable)
1904 need_to_kill = false;
1906 mem_cgroup_oom_notify(memcg);
1907 spin_unlock(&memcg_oom_lock);
1910 finish_wait(&memcg_oom_waitq, &owait.wait);
1911 mem_cgroup_out_of_memory(memcg, mask, order);
1914 finish_wait(&memcg_oom_waitq, &owait.wait);
1916 spin_lock(&memcg_oom_lock);
1918 mem_cgroup_oom_unlock(memcg);
1919 memcg_wakeup_oom(memcg);
1920 spin_unlock(&memcg_oom_lock);
1922 mem_cgroup_unmark_under_oom(memcg);
1924 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1926 /* Give chance to dying process */
1927 schedule_timeout_uninterruptible(1);
1932 * Currently used to update mapped file statistics, but the routine can be
1933 * generalized to update other statistics as well.
1935 * Notes: Race condition
1937 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1938 * it tends to be costly. But considering some conditions, we doesn't need
1939 * to do so _always_.
1941 * Considering "charge", lock_page_cgroup() is not required because all
1942 * file-stat operations happen after a page is attached to radix-tree. There
1943 * are no race with "charge".
1945 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1946 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1947 * if there are race with "uncharge". Statistics itself is properly handled
1950 * Considering "move", this is an only case we see a race. To make the race
1951 * small, we check mm->moving_account and detect there are possibility of race
1952 * If there is, we take a lock.
1955 void __mem_cgroup_begin_update_page_stat(struct page *page,
1956 bool *locked, unsigned long *flags)
1958 struct mem_cgroup *memcg;
1959 struct page_cgroup *pc;
1961 pc = lookup_page_cgroup(page);
1963 memcg = pc->mem_cgroup;
1964 if (unlikely(!memcg || !PageCgroupUsed(pc)))
1967 * If this memory cgroup is not under account moving, we don't
1968 * need to take move_lock_mem_cgroup(). Because we already hold
1969 * rcu_read_lock(), any calls to move_account will be delayed until
1970 * rcu_read_unlock() if mem_cgroup_stolen() == true.
1972 if (!mem_cgroup_stolen(memcg))
1975 move_lock_mem_cgroup(memcg, flags);
1976 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
1977 move_unlock_mem_cgroup(memcg, flags);
1983 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
1985 struct page_cgroup *pc = lookup_page_cgroup(page);
1988 * It's guaranteed that pc->mem_cgroup never changes while
1989 * lock is held because a routine modifies pc->mem_cgroup
1990 * should take move_lock_mem_cgroup().
1992 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
1995 void mem_cgroup_update_page_stat(struct page *page,
1996 enum mem_cgroup_page_stat_item idx, int val)
1998 struct mem_cgroup *memcg;
1999 struct page_cgroup *pc = lookup_page_cgroup(page);
2000 unsigned long uninitialized_var(flags);
2002 if (mem_cgroup_disabled())
2005 memcg = pc->mem_cgroup;
2006 if (unlikely(!memcg || !PageCgroupUsed(pc)))
2010 case MEMCG_NR_FILE_MAPPED:
2011 idx = MEM_CGROUP_STAT_FILE_MAPPED;
2017 this_cpu_add(memcg->stat->count[idx], val);
2021 * size of first charge trial. "32" comes from vmscan.c's magic value.
2022 * TODO: maybe necessary to use big numbers in big irons.
2024 #define CHARGE_BATCH 32U
2025 struct memcg_stock_pcp {
2026 struct mem_cgroup *cached; /* this never be root cgroup */
2027 unsigned int nr_pages;
2028 struct work_struct work;
2029 unsigned long flags;
2030 #define FLUSHING_CACHED_CHARGE 0
2032 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2033 static DEFINE_MUTEX(percpu_charge_mutex);
2036 * Try to consume stocked charge on this cpu. If success, one page is consumed
2037 * from local stock and true is returned. If the stock is 0 or charges from a
2038 * cgroup which is not current target, returns false. This stock will be
2041 static bool consume_stock(struct mem_cgroup *memcg)
2043 struct memcg_stock_pcp *stock;
2046 stock = &get_cpu_var(memcg_stock);
2047 if (memcg == stock->cached && stock->nr_pages)
2049 else /* need to call res_counter_charge */
2051 put_cpu_var(memcg_stock);
2056 * Returns stocks cached in percpu to res_counter and reset cached information.
2058 static void drain_stock(struct memcg_stock_pcp *stock)
2060 struct mem_cgroup *old = stock->cached;
2062 if (stock->nr_pages) {
2063 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
2065 res_counter_uncharge(&old->res, bytes);
2066 if (do_swap_account)
2067 res_counter_uncharge(&old->memsw, bytes);
2068 stock->nr_pages = 0;
2070 stock->cached = NULL;
2074 * This must be called under preempt disabled or must be called by
2075 * a thread which is pinned to local cpu.
2077 static void drain_local_stock(struct work_struct *dummy)
2079 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2081 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2085 * Cache charges(val) which is from res_counter, to local per_cpu area.
2086 * This will be consumed by consume_stock() function, later.
2088 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2090 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2092 if (stock->cached != memcg) { /* reset if necessary */
2094 stock->cached = memcg;
2096 stock->nr_pages += nr_pages;
2097 put_cpu_var(memcg_stock);
2101 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2102 * of the hierarchy under it. sync flag says whether we should block
2103 * until the work is done.
2105 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2109 /* Notify other cpus that system-wide "drain" is running */
2112 for_each_online_cpu(cpu) {
2113 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2114 struct mem_cgroup *memcg;
2116 memcg = stock->cached;
2117 if (!memcg || !stock->nr_pages)
2119 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2121 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2123 drain_local_stock(&stock->work);
2125 schedule_work_on(cpu, &stock->work);
2133 for_each_online_cpu(cpu) {
2134 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2135 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2136 flush_work(&stock->work);
2143 * Tries to drain stocked charges in other cpus. This function is asynchronous
2144 * and just put a work per cpu for draining localy on each cpu. Caller can
2145 * expects some charges will be back to res_counter later but cannot wait for
2148 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2151 * If someone calls draining, avoid adding more kworker runs.
2153 if (!mutex_trylock(&percpu_charge_mutex))
2155 drain_all_stock(root_memcg, false);
2156 mutex_unlock(&percpu_charge_mutex);
2159 /* This is a synchronous drain interface. */
2160 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2162 /* called when force_empty is called */
2163 mutex_lock(&percpu_charge_mutex);
2164 drain_all_stock(root_memcg, true);
2165 mutex_unlock(&percpu_charge_mutex);
2169 * This function drains percpu counter value from DEAD cpu and
2170 * move it to local cpu. Note that this function can be preempted.
2172 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2176 spin_lock(&memcg->pcp_counter_lock);
2177 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2178 long x = per_cpu(memcg->stat->count[i], cpu);
2180 per_cpu(memcg->stat->count[i], cpu) = 0;
2181 memcg->nocpu_base.count[i] += x;
2183 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2184 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2186 per_cpu(memcg->stat->events[i], cpu) = 0;
2187 memcg->nocpu_base.events[i] += x;
2189 spin_unlock(&memcg->pcp_counter_lock);
2192 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2193 unsigned long action,
2196 int cpu = (unsigned long)hcpu;
2197 struct memcg_stock_pcp *stock;
2198 struct mem_cgroup *iter;
2200 if (action == CPU_ONLINE)
2203 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2206 for_each_mem_cgroup(iter)
2207 mem_cgroup_drain_pcp_counter(iter, cpu);
2209 stock = &per_cpu(memcg_stock, cpu);
2215 /* See __mem_cgroup_try_charge() for details */
2217 CHARGE_OK, /* success */
2218 CHARGE_RETRY, /* need to retry but retry is not bad */
2219 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2220 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
2221 CHARGE_OOM_DIE, /* the current is killed because of OOM */
2224 static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2225 unsigned int nr_pages, bool oom_check)
2227 unsigned long csize = nr_pages * PAGE_SIZE;
2228 struct mem_cgroup *mem_over_limit;
2229 struct res_counter *fail_res;
2230 unsigned long flags = 0;
2233 ret = res_counter_charge(&memcg->res, csize, &fail_res);
2236 if (!do_swap_account)
2238 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2242 res_counter_uncharge(&memcg->res, csize);
2243 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2244 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2246 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2248 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
2249 * of regular pages (CHARGE_BATCH), or a single regular page (1).
2251 * Never reclaim on behalf of optional batching, retry with a
2252 * single page instead.
2254 if (nr_pages == CHARGE_BATCH)
2255 return CHARGE_RETRY;
2257 if (!(gfp_mask & __GFP_WAIT))
2258 return CHARGE_WOULDBLOCK;
2260 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2261 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2262 return CHARGE_RETRY;
2264 * Even though the limit is exceeded at this point, reclaim
2265 * may have been able to free some pages. Retry the charge
2266 * before killing the task.
2268 * Only for regular pages, though: huge pages are rather
2269 * unlikely to succeed so close to the limit, and we fall back
2270 * to regular pages anyway in case of failure.
2272 if (nr_pages == 1 && ret)
2273 return CHARGE_RETRY;
2276 * At task move, charge accounts can be doubly counted. So, it's
2277 * better to wait until the end of task_move if something is going on.
2279 if (mem_cgroup_wait_acct_move(mem_over_limit))
2280 return CHARGE_RETRY;
2282 /* If we don't need to call oom-killer at el, return immediately */
2284 return CHARGE_NOMEM;
2286 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))
2287 return CHARGE_OOM_DIE;
2289 return CHARGE_RETRY;
2293 * __mem_cgroup_try_charge() does
2294 * 1. detect memcg to be charged against from passed *mm and *ptr,
2295 * 2. update res_counter
2296 * 3. call memory reclaim if necessary.
2298 * In some special case, if the task is fatal, fatal_signal_pending() or
2299 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2300 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2301 * as possible without any hazards. 2: all pages should have a valid
2302 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2303 * pointer, that is treated as a charge to root_mem_cgroup.
2305 * So __mem_cgroup_try_charge() will return
2306 * 0 ... on success, filling *ptr with a valid memcg pointer.
2307 * -ENOMEM ... charge failure because of resource limits.
2308 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2310 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2311 * the oom-killer can be invoked.
2313 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2315 unsigned int nr_pages,
2316 struct mem_cgroup **ptr,
2319 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2320 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2321 struct mem_cgroup *memcg = NULL;
2325 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2326 * in system level. So, allow to go ahead dying process in addition to
2329 if (unlikely(test_thread_flag(TIF_MEMDIE)
2330 || fatal_signal_pending(current)))
2334 * We always charge the cgroup the mm_struct belongs to.
2335 * The mm_struct's mem_cgroup changes on task migration if the
2336 * thread group leader migrates. It's possible that mm is not
2337 * set, if so charge the init_mm (happens for pagecache usage).
2340 *ptr = root_mem_cgroup;
2342 if (*ptr) { /* css should be a valid one */
2344 VM_BUG_ON(css_is_removed(&memcg->css));
2345 if (mem_cgroup_is_root(memcg))
2347 if (nr_pages == 1 && consume_stock(memcg))
2349 css_get(&memcg->css);
2351 struct task_struct *p;
2354 p = rcu_dereference(mm->owner);
2356 * Because we don't have task_lock(), "p" can exit.
2357 * In that case, "memcg" can point to root or p can be NULL with
2358 * race with swapoff. Then, we have small risk of mis-accouning.
2359 * But such kind of mis-account by race always happens because
2360 * we don't have cgroup_mutex(). It's overkill and we allo that
2362 * (*) swapoff at el will charge against mm-struct not against
2363 * task-struct. So, mm->owner can be NULL.
2365 memcg = mem_cgroup_from_task(p);
2367 memcg = root_mem_cgroup;
2368 if (mem_cgroup_is_root(memcg)) {
2372 if (nr_pages == 1 && consume_stock(memcg)) {
2374 * It seems dagerous to access memcg without css_get().
2375 * But considering how consume_stok works, it's not
2376 * necessary. If consume_stock success, some charges
2377 * from this memcg are cached on this cpu. So, we
2378 * don't need to call css_get()/css_tryget() before
2379 * calling consume_stock().
2384 /* after here, we may be blocked. we need to get refcnt */
2385 if (!css_tryget(&memcg->css)) {
2395 /* If killed, bypass charge */
2396 if (fatal_signal_pending(current)) {
2397 css_put(&memcg->css);
2402 if (oom && !nr_oom_retries) {
2404 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2407 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
2411 case CHARGE_RETRY: /* not in OOM situation but retry */
2413 css_put(&memcg->css);
2416 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2417 css_put(&memcg->css);
2419 case CHARGE_NOMEM: /* OOM routine works */
2421 css_put(&memcg->css);
2424 /* If oom, we never return -ENOMEM */
2427 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2428 css_put(&memcg->css);
2431 } while (ret != CHARGE_OK);
2433 if (batch > nr_pages)
2434 refill_stock(memcg, batch - nr_pages);
2435 css_put(&memcg->css);
2443 *ptr = root_mem_cgroup;
2448 * Somemtimes we have to undo a charge we got by try_charge().
2449 * This function is for that and do uncharge, put css's refcnt.
2450 * gotten by try_charge().
2452 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2453 unsigned int nr_pages)
2455 if (!mem_cgroup_is_root(memcg)) {
2456 unsigned long bytes = nr_pages * PAGE_SIZE;
2458 res_counter_uncharge(&memcg->res, bytes);
2459 if (do_swap_account)
2460 res_counter_uncharge(&memcg->memsw, bytes);
2465 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2466 * This is useful when moving usage to parent cgroup.
2468 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2469 unsigned int nr_pages)
2471 unsigned long bytes = nr_pages * PAGE_SIZE;
2473 if (mem_cgroup_is_root(memcg))
2476 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2477 if (do_swap_account)
2478 res_counter_uncharge_until(&memcg->memsw,
2479 memcg->memsw.parent, bytes);
2483 * A helper function to get mem_cgroup from ID. must be called under
2484 * rcu_read_lock(). The caller must check css_is_removed() or some if
2485 * it's concern. (dropping refcnt from swap can be called against removed
2488 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2490 struct cgroup_subsys_state *css;
2492 /* ID 0 is unused ID */
2495 css = css_lookup(&mem_cgroup_subsys, id);
2498 return container_of(css, struct mem_cgroup, css);
2501 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2503 struct mem_cgroup *memcg = NULL;
2504 struct page_cgroup *pc;
2508 VM_BUG_ON(!PageLocked(page));
2510 pc = lookup_page_cgroup(page);
2511 lock_page_cgroup(pc);
2512 if (PageCgroupUsed(pc)) {
2513 memcg = pc->mem_cgroup;
2514 if (memcg && !css_tryget(&memcg->css))
2516 } else if (PageSwapCache(page)) {
2517 ent.val = page_private(page);
2518 id = lookup_swap_cgroup_id(ent);
2520 memcg = mem_cgroup_lookup(id);
2521 if (memcg && !css_tryget(&memcg->css))
2525 unlock_page_cgroup(pc);
2529 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2531 unsigned int nr_pages,
2532 enum charge_type ctype,
2535 struct page_cgroup *pc = lookup_page_cgroup(page);
2536 struct zone *uninitialized_var(zone);
2537 struct lruvec *lruvec;
2538 bool was_on_lru = false;
2541 lock_page_cgroup(pc);
2542 if (unlikely(PageCgroupUsed(pc))) {
2543 unlock_page_cgroup(pc);
2544 __mem_cgroup_cancel_charge(memcg, nr_pages);
2548 * we don't need page_cgroup_lock about tail pages, becase they are not
2549 * accessed by any other context at this point.
2553 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2554 * may already be on some other mem_cgroup's LRU. Take care of it.
2557 zone = page_zone(page);
2558 spin_lock_irq(&zone->lru_lock);
2559 if (PageLRU(page)) {
2560 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2562 del_page_from_lru_list(page, lruvec, page_lru(page));
2567 pc->mem_cgroup = memcg;
2569 * We access a page_cgroup asynchronously without lock_page_cgroup().
2570 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2571 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2572 * before USED bit, we need memory barrier here.
2573 * See mem_cgroup_add_lru_list(), etc.
2576 SetPageCgroupUsed(pc);
2580 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2581 VM_BUG_ON(PageLRU(page));
2583 add_page_to_lru_list(page, lruvec, page_lru(page));
2585 spin_unlock_irq(&zone->lru_lock);
2588 if (ctype == MEM_CGROUP_CHARGE_TYPE_ANON)
2593 mem_cgroup_charge_statistics(memcg, anon, nr_pages);
2594 unlock_page_cgroup(pc);
2597 * "charge_statistics" updated event counter. Then, check it.
2598 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2599 * if they exceeds softlimit.
2601 memcg_check_events(memcg, page);
2604 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2606 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
2608 * Because tail pages are not marked as "used", set it. We're under
2609 * zone->lru_lock, 'splitting on pmd' and compound_lock.
2610 * charge/uncharge will be never happen and move_account() is done under
2611 * compound_lock(), so we don't have to take care of races.
2613 void mem_cgroup_split_huge_fixup(struct page *head)
2615 struct page_cgroup *head_pc = lookup_page_cgroup(head);
2616 struct page_cgroup *pc;
2619 if (mem_cgroup_disabled())
2621 for (i = 1; i < HPAGE_PMD_NR; i++) {
2623 pc->mem_cgroup = head_pc->mem_cgroup;
2624 smp_wmb();/* see __commit_charge() */
2625 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2628 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2631 * mem_cgroup_move_account - move account of the page
2633 * @nr_pages: number of regular pages (>1 for huge pages)
2634 * @pc: page_cgroup of the page.
2635 * @from: mem_cgroup which the page is moved from.
2636 * @to: mem_cgroup which the page is moved to. @from != @to.
2638 * The caller must confirm following.
2639 * - page is not on LRU (isolate_page() is useful.)
2640 * - compound_lock is held when nr_pages > 1
2642 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
2645 static int mem_cgroup_move_account(struct page *page,
2646 unsigned int nr_pages,
2647 struct page_cgroup *pc,
2648 struct mem_cgroup *from,
2649 struct mem_cgroup *to)
2651 unsigned long flags;
2653 bool anon = PageAnon(page);
2655 VM_BUG_ON(from == to);
2656 VM_BUG_ON(PageLRU(page));
2658 * The page is isolated from LRU. So, collapse function
2659 * will not handle this page. But page splitting can happen.
2660 * Do this check under compound_page_lock(). The caller should
2664 if (nr_pages > 1 && !PageTransHuge(page))
2667 lock_page_cgroup(pc);
2670 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2673 move_lock_mem_cgroup(from, &flags);
2675 if (!anon && page_mapped(page)) {
2676 /* Update mapped_file data for mem_cgroup */
2678 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2679 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2682 mem_cgroup_charge_statistics(from, anon, -nr_pages);
2684 /* caller should have done css_get */
2685 pc->mem_cgroup = to;
2686 mem_cgroup_charge_statistics(to, anon, nr_pages);
2688 * We charges against "to" which may not have any tasks. Then, "to"
2689 * can be under rmdir(). But in current implementation, caller of
2690 * this function is just force_empty() and move charge, so it's
2691 * guaranteed that "to" is never removed. So, we don't check rmdir
2694 move_unlock_mem_cgroup(from, &flags);
2697 unlock_page_cgroup(pc);
2701 memcg_check_events(to, page);
2702 memcg_check_events(from, page);
2708 * move charges to its parent.
2711 static int mem_cgroup_move_parent(struct page *page,
2712 struct page_cgroup *pc,
2713 struct mem_cgroup *child)
2715 struct mem_cgroup *parent;
2716 unsigned int nr_pages;
2717 unsigned long uninitialized_var(flags);
2721 if (mem_cgroup_is_root(child))
2725 if (!get_page_unless_zero(page))
2727 if (isolate_lru_page(page))
2730 nr_pages = hpage_nr_pages(page);
2732 parent = parent_mem_cgroup(child);
2734 * If no parent, move charges to root cgroup.
2737 parent = root_mem_cgroup;
2740 flags = compound_lock_irqsave(page);
2742 ret = mem_cgroup_move_account(page, nr_pages,
2745 __mem_cgroup_cancel_local_charge(child, nr_pages);
2748 compound_unlock_irqrestore(page, flags);
2749 putback_lru_page(page);
2757 * Charge the memory controller for page usage.
2759 * 0 if the charge was successful
2760 * < 0 if the cgroup is over its limit
2762 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2763 gfp_t gfp_mask, enum charge_type ctype)
2765 struct mem_cgroup *memcg = NULL;
2766 unsigned int nr_pages = 1;
2770 if (PageTransHuge(page)) {
2771 nr_pages <<= compound_order(page);
2772 VM_BUG_ON(!PageTransHuge(page));
2774 * Never OOM-kill a process for a huge page. The
2775 * fault handler will fall back to regular pages.
2780 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
2783 __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
2787 int mem_cgroup_newpage_charge(struct page *page,
2788 struct mm_struct *mm, gfp_t gfp_mask)
2790 if (mem_cgroup_disabled())
2792 VM_BUG_ON(page_mapped(page));
2793 VM_BUG_ON(page->mapping && !PageAnon(page));
2795 return mem_cgroup_charge_common(page, mm, gfp_mask,
2796 MEM_CGROUP_CHARGE_TYPE_ANON);
2800 * While swap-in, try_charge -> commit or cancel, the page is locked.
2801 * And when try_charge() successfully returns, one refcnt to memcg without
2802 * struct page_cgroup is acquired. This refcnt will be consumed by
2803 * "commit()" or removed by "cancel()"
2805 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2807 gfp_t mask, struct mem_cgroup **memcgp)
2809 struct mem_cgroup *memcg;
2814 if (mem_cgroup_disabled())
2817 if (!do_swap_account)
2820 * A racing thread's fault, or swapoff, may have already updated
2821 * the pte, and even removed page from swap cache: in those cases
2822 * do_swap_page()'s pte_same() test will fail; but there's also a
2823 * KSM case which does need to charge the page.
2825 if (!PageSwapCache(page))
2827 memcg = try_get_mem_cgroup_from_page(page);
2831 ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
2832 css_put(&memcg->css);
2839 ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
2845 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
2847 if (mem_cgroup_disabled())
2851 __mem_cgroup_cancel_charge(memcg, 1);
2855 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
2856 enum charge_type ctype)
2858 if (mem_cgroup_disabled())
2862 cgroup_exclude_rmdir(&memcg->css);
2864 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
2866 * Now swap is on-memory. This means this page may be
2867 * counted both as mem and swap....double count.
2868 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2869 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2870 * may call delete_from_swap_cache() before reach here.
2872 if (do_swap_account && PageSwapCache(page)) {
2873 swp_entry_t ent = {.val = page_private(page)};
2874 mem_cgroup_uncharge_swap(ent);
2877 * At swapin, we may charge account against cgroup which has no tasks.
2878 * So, rmdir()->pre_destroy() can be called while we do this charge.
2879 * In that case, we need to call pre_destroy() again. check it here.
2881 cgroup_release_and_wakeup_rmdir(&memcg->css);
2884 void mem_cgroup_commit_charge_swapin(struct page *page,
2885 struct mem_cgroup *memcg)
2887 __mem_cgroup_commit_charge_swapin(page, memcg,
2888 MEM_CGROUP_CHARGE_TYPE_ANON);
2891 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2894 struct mem_cgroup *memcg = NULL;
2895 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
2898 if (mem_cgroup_disabled())
2900 if (PageCompound(page))
2905 if (!page_is_file_cache(page))
2906 type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2908 if (!PageSwapCache(page))
2909 ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
2910 else { /* page is swapcache/shmem */
2911 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg);
2913 __mem_cgroup_commit_charge_swapin(page, memcg, type);
2918 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
2919 unsigned int nr_pages,
2920 const enum charge_type ctype)
2922 struct memcg_batch_info *batch = NULL;
2923 bool uncharge_memsw = true;
2925 /* If swapout, usage of swap doesn't decrease */
2926 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2927 uncharge_memsw = false;
2929 batch = ¤t->memcg_batch;
2931 * In usual, we do css_get() when we remember memcg pointer.
2932 * But in this case, we keep res->usage until end of a series of
2933 * uncharges. Then, it's ok to ignore memcg's refcnt.
2936 batch->memcg = memcg;
2938 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2939 * In those cases, all pages freed continuously can be expected to be in
2940 * the same cgroup and we have chance to coalesce uncharges.
2941 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2942 * because we want to do uncharge as soon as possible.
2945 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2946 goto direct_uncharge;
2949 goto direct_uncharge;
2952 * In typical case, batch->memcg == mem. This means we can
2953 * merge a series of uncharges to an uncharge of res_counter.
2954 * If not, we uncharge res_counter ony by one.
2956 if (batch->memcg != memcg)
2957 goto direct_uncharge;
2958 /* remember freed charge and uncharge it later */
2961 batch->memsw_nr_pages++;
2964 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
2966 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
2967 if (unlikely(batch->memcg != memcg))
2968 memcg_oom_recover(memcg);
2972 * uncharge if !page_mapped(page)
2974 static struct mem_cgroup *
2975 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype,
2978 struct mem_cgroup *memcg = NULL;
2979 unsigned int nr_pages = 1;
2980 struct page_cgroup *pc;
2983 if (mem_cgroup_disabled())
2986 VM_BUG_ON(PageSwapCache(page));
2988 if (PageTransHuge(page)) {
2989 nr_pages <<= compound_order(page);
2990 VM_BUG_ON(!PageTransHuge(page));
2993 * Check if our page_cgroup is valid
2995 pc = lookup_page_cgroup(page);
2996 if (unlikely(!PageCgroupUsed(pc)))
2999 lock_page_cgroup(pc);
3001 memcg = pc->mem_cgroup;
3003 if (!PageCgroupUsed(pc))
3006 anon = PageAnon(page);
3009 case MEM_CGROUP_CHARGE_TYPE_ANON:
3011 * Generally PageAnon tells if it's the anon statistics to be
3012 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3013 * used before page reached the stage of being marked PageAnon.
3017 case MEM_CGROUP_CHARGE_TYPE_DROP:
3018 /* See mem_cgroup_prepare_migration() */
3019 if (page_mapped(page))
3022 * Pages under migration may not be uncharged. But
3023 * end_migration() /must/ be the one uncharging the
3024 * unused post-migration page and so it has to call
3025 * here with the migration bit still set. See the
3026 * res_counter handling below.
3028 if (!end_migration && PageCgroupMigration(pc))
3031 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
3032 if (!PageAnon(page)) { /* Shared memory */
3033 if (page->mapping && !page_is_file_cache(page))
3035 } else if (page_mapped(page)) /* Anon */
3042 mem_cgroup_charge_statistics(memcg, anon, -nr_pages);
3044 ClearPageCgroupUsed(pc);
3046 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3047 * freed from LRU. This is safe because uncharged page is expected not
3048 * to be reused (freed soon). Exception is SwapCache, it's handled by
3049 * special functions.
3052 unlock_page_cgroup(pc);
3054 * even after unlock, we have memcg->res.usage here and this memcg
3055 * will never be freed.
3057 memcg_check_events(memcg, page);
3058 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
3059 mem_cgroup_swap_statistics(memcg, true);
3060 mem_cgroup_get(memcg);
3063 * Migration does not charge the res_counter for the
3064 * replacement page, so leave it alone when phasing out the
3065 * page that is unused after the migration.
3067 if (!end_migration && !mem_cgroup_is_root(memcg))
3068 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
3073 unlock_page_cgroup(pc);
3077 void mem_cgroup_uncharge_page(struct page *page)
3080 if (page_mapped(page))
3082 VM_BUG_ON(page->mapping && !PageAnon(page));
3083 if (PageSwapCache(page))
3085 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_ANON, false);
3088 void mem_cgroup_uncharge_cache_page(struct page *page)
3090 VM_BUG_ON(page_mapped(page));
3091 VM_BUG_ON(page->mapping);
3092 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE, false);
3096 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3097 * In that cases, pages are freed continuously and we can expect pages
3098 * are in the same memcg. All these calls itself limits the number of
3099 * pages freed at once, then uncharge_start/end() is called properly.
3100 * This may be called prural(2) times in a context,
3103 void mem_cgroup_uncharge_start(void)
3105 current->memcg_batch.do_batch++;
3106 /* We can do nest. */
3107 if (current->memcg_batch.do_batch == 1) {
3108 current->memcg_batch.memcg = NULL;
3109 current->memcg_batch.nr_pages = 0;
3110 current->memcg_batch.memsw_nr_pages = 0;
3114 void mem_cgroup_uncharge_end(void)
3116 struct memcg_batch_info *batch = ¤t->memcg_batch;
3118 if (!batch->do_batch)
3122 if (batch->do_batch) /* If stacked, do nothing. */
3128 * This "batch->memcg" is valid without any css_get/put etc...
3129 * bacause we hide charges behind us.
3131 if (batch->nr_pages)
3132 res_counter_uncharge(&batch->memcg->res,
3133 batch->nr_pages * PAGE_SIZE);
3134 if (batch->memsw_nr_pages)
3135 res_counter_uncharge(&batch->memcg->memsw,
3136 batch->memsw_nr_pages * PAGE_SIZE);
3137 memcg_oom_recover(batch->memcg);
3138 /* forget this pointer (for sanity check) */
3139 batch->memcg = NULL;
3144 * called after __delete_from_swap_cache() and drop "page" account.
3145 * memcg information is recorded to swap_cgroup of "ent"
3148 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
3150 struct mem_cgroup *memcg;
3151 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
3153 if (!swapout) /* this was a swap cache but the swap is unused ! */
3154 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
3156 memcg = __mem_cgroup_uncharge_common(page, ctype, false);
3159 * record memcg information, if swapout && memcg != NULL,
3160 * mem_cgroup_get() was called in uncharge().
3162 if (do_swap_account && swapout && memcg)
3163 swap_cgroup_record(ent, css_id(&memcg->css));
3167 #ifdef CONFIG_MEMCG_SWAP
3169 * called from swap_entry_free(). remove record in swap_cgroup and
3170 * uncharge "memsw" account.
3172 void mem_cgroup_uncharge_swap(swp_entry_t ent)
3174 struct mem_cgroup *memcg;
3177 if (!do_swap_account)
3180 id = swap_cgroup_record(ent, 0);
3182 memcg = mem_cgroup_lookup(id);
3185 * We uncharge this because swap is freed.
3186 * This memcg can be obsolete one. We avoid calling css_tryget
3188 if (!mem_cgroup_is_root(memcg))
3189 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
3190 mem_cgroup_swap_statistics(memcg, false);
3191 mem_cgroup_put(memcg);
3197 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3198 * @entry: swap entry to be moved
3199 * @from: mem_cgroup which the entry is moved from
3200 * @to: mem_cgroup which the entry is moved to
3202 * It succeeds only when the swap_cgroup's record for this entry is the same
3203 * as the mem_cgroup's id of @from.
3205 * Returns 0 on success, -EINVAL on failure.
3207 * The caller must have charged to @to, IOW, called res_counter_charge() about
3208 * both res and memsw, and called css_get().
3210 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3211 struct mem_cgroup *from, struct mem_cgroup *to)
3213 unsigned short old_id, new_id;
3215 old_id = css_id(&from->css);
3216 new_id = css_id(&to->css);
3218 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3219 mem_cgroup_swap_statistics(from, false);
3220 mem_cgroup_swap_statistics(to, true);
3222 * This function is only called from task migration context now.
3223 * It postpones res_counter and refcount handling till the end
3224 * of task migration(mem_cgroup_clear_mc()) for performance
3225 * improvement. But we cannot postpone mem_cgroup_get(to)
3226 * because if the process that has been moved to @to does
3227 * swap-in, the refcount of @to might be decreased to 0.
3235 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3236 struct mem_cgroup *from, struct mem_cgroup *to)
3243 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
3246 void mem_cgroup_prepare_migration(struct page *page, struct page *newpage,
3247 struct mem_cgroup **memcgp)
3249 struct mem_cgroup *memcg = NULL;
3250 struct page_cgroup *pc;
3251 enum charge_type ctype;
3255 VM_BUG_ON(PageTransHuge(page));
3256 if (mem_cgroup_disabled())
3259 pc = lookup_page_cgroup(page);
3260 lock_page_cgroup(pc);
3261 if (PageCgroupUsed(pc)) {
3262 memcg = pc->mem_cgroup;
3263 css_get(&memcg->css);
3265 * At migrating an anonymous page, its mapcount goes down
3266 * to 0 and uncharge() will be called. But, even if it's fully
3267 * unmapped, migration may fail and this page has to be
3268 * charged again. We set MIGRATION flag here and delay uncharge
3269 * until end_migration() is called
3271 * Corner Case Thinking
3273 * When the old page was mapped as Anon and it's unmap-and-freed
3274 * while migration was ongoing.
3275 * If unmap finds the old page, uncharge() of it will be delayed
3276 * until end_migration(). If unmap finds a new page, it's
3277 * uncharged when it make mapcount to be 1->0. If unmap code
3278 * finds swap_migration_entry, the new page will not be mapped
3279 * and end_migration() will find it(mapcount==0).
3282 * When the old page was mapped but migraion fails, the kernel
3283 * remaps it. A charge for it is kept by MIGRATION flag even
3284 * if mapcount goes down to 0. We can do remap successfully
3285 * without charging it again.
3288 * The "old" page is under lock_page() until the end of
3289 * migration, so, the old page itself will not be swapped-out.
3290 * If the new page is swapped out before end_migraton, our
3291 * hook to usual swap-out path will catch the event.
3294 SetPageCgroupMigration(pc);
3296 unlock_page_cgroup(pc);
3298 * If the page is not charged at this point,
3306 * We charge new page before it's used/mapped. So, even if unlock_page()
3307 * is called before end_migration, we can catch all events on this new
3308 * page. In the case new page is migrated but not remapped, new page's
3309 * mapcount will be finally 0 and we call uncharge in end_migration().
3312 ctype = MEM_CGROUP_CHARGE_TYPE_ANON;
3313 else if (page_is_file_cache(page))
3314 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
3316 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3318 * The page is committed to the memcg, but it's not actually
3319 * charged to the res_counter since we plan on replacing the
3320 * old one and only one page is going to be left afterwards.
3322 __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
3325 /* remove redundant charge if migration failed*/
3326 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
3327 struct page *oldpage, struct page *newpage, bool migration_ok)
3329 struct page *used, *unused;
3330 struct page_cgroup *pc;
3335 /* blocks rmdir() */
3336 cgroup_exclude_rmdir(&memcg->css);
3337 if (!migration_ok) {
3344 anon = PageAnon(used);
3345 __mem_cgroup_uncharge_common(unused,
3346 anon ? MEM_CGROUP_CHARGE_TYPE_ANON
3347 : MEM_CGROUP_CHARGE_TYPE_CACHE,
3349 css_put(&memcg->css);
3351 * We disallowed uncharge of pages under migration because mapcount
3352 * of the page goes down to zero, temporarly.
3353 * Clear the flag and check the page should be charged.
3355 pc = lookup_page_cgroup(oldpage);
3356 lock_page_cgroup(pc);
3357 ClearPageCgroupMigration(pc);
3358 unlock_page_cgroup(pc);
3361 * If a page is a file cache, radix-tree replacement is very atomic
3362 * and we can skip this check. When it was an Anon page, its mapcount
3363 * goes down to 0. But because we added MIGRATION flage, it's not
3364 * uncharged yet. There are several case but page->mapcount check
3365 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3366 * check. (see prepare_charge() also)
3369 mem_cgroup_uncharge_page(used);
3371 * At migration, we may charge account against cgroup which has no
3373 * So, rmdir()->pre_destroy() can be called while we do this charge.
3374 * In that case, we need to call pre_destroy() again. check it here.
3376 cgroup_release_and_wakeup_rmdir(&memcg->css);
3380 * At replace page cache, newpage is not under any memcg but it's on
3381 * LRU. So, this function doesn't touch res_counter but handles LRU
3382 * in correct way. Both pages are locked so we cannot race with uncharge.
3384 void mem_cgroup_replace_page_cache(struct page *oldpage,
3385 struct page *newpage)
3387 struct mem_cgroup *memcg = NULL;
3388 struct page_cgroup *pc;
3389 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3391 if (mem_cgroup_disabled())
3394 pc = lookup_page_cgroup(oldpage);
3395 /* fix accounting on old pages */
3396 lock_page_cgroup(pc);
3397 if (PageCgroupUsed(pc)) {
3398 memcg = pc->mem_cgroup;
3399 mem_cgroup_charge_statistics(memcg, false, -1);
3400 ClearPageCgroupUsed(pc);
3402 unlock_page_cgroup(pc);
3405 * When called from shmem_replace_page(), in some cases the
3406 * oldpage has already been charged, and in some cases not.
3411 if (PageSwapBacked(oldpage))
3412 type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3415 * Even if newpage->mapping was NULL before starting replacement,
3416 * the newpage may be on LRU(or pagevec for LRU) already. We lock
3417 * LRU while we overwrite pc->mem_cgroup.
3419 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
3422 #ifdef CONFIG_DEBUG_VM
3423 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3425 struct page_cgroup *pc;
3427 pc = lookup_page_cgroup(page);
3429 * Can be NULL while feeding pages into the page allocator for
3430 * the first time, i.e. during boot or memory hotplug;
3431 * or when mem_cgroup_disabled().
3433 if (likely(pc) && PageCgroupUsed(pc))
3438 bool mem_cgroup_bad_page_check(struct page *page)
3440 if (mem_cgroup_disabled())
3443 return lookup_page_cgroup_used(page) != NULL;
3446 void mem_cgroup_print_bad_page(struct page *page)
3448 struct page_cgroup *pc;
3450 pc = lookup_page_cgroup_used(page);
3452 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
3453 pc, pc->flags, pc->mem_cgroup);
3458 static DEFINE_MUTEX(set_limit_mutex);
3460 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3461 unsigned long long val)
3464 u64 memswlimit, memlimit;
3466 int children = mem_cgroup_count_children(memcg);
3467 u64 curusage, oldusage;
3471 * For keeping hierarchical_reclaim simple, how long we should retry
3472 * is depends on callers. We set our retry-count to be function
3473 * of # of children which we should visit in this loop.
3475 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3477 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3480 while (retry_count) {
3481 if (signal_pending(current)) {
3486 * Rather than hide all in some function, I do this in
3487 * open coded manner. You see what this really does.
3488 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3490 mutex_lock(&set_limit_mutex);
3491 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3492 if (memswlimit < val) {
3494 mutex_unlock(&set_limit_mutex);
3498 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3502 ret = res_counter_set_limit(&memcg->res, val);
3504 if (memswlimit == val)
3505 memcg->memsw_is_minimum = true;
3507 memcg->memsw_is_minimum = false;
3509 mutex_unlock(&set_limit_mutex);
3514 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3515 MEM_CGROUP_RECLAIM_SHRINK);
3516 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3517 /* Usage is reduced ? */
3518 if (curusage >= oldusage)
3521 oldusage = curusage;
3523 if (!ret && enlarge)
3524 memcg_oom_recover(memcg);
3529 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3530 unsigned long long val)
3533 u64 memlimit, memswlimit, oldusage, curusage;
3534 int children = mem_cgroup_count_children(memcg);
3538 /* see mem_cgroup_resize_res_limit */
3539 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3540 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3541 while (retry_count) {
3542 if (signal_pending(current)) {
3547 * Rather than hide all in some function, I do this in
3548 * open coded manner. You see what this really does.
3549 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3551 mutex_lock(&set_limit_mutex);
3552 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3553 if (memlimit > val) {
3555 mutex_unlock(&set_limit_mutex);
3558 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3559 if (memswlimit < val)
3561 ret = res_counter_set_limit(&memcg->memsw, val);
3563 if (memlimit == val)
3564 memcg->memsw_is_minimum = true;
3566 memcg->memsw_is_minimum = false;
3568 mutex_unlock(&set_limit_mutex);
3573 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3574 MEM_CGROUP_RECLAIM_NOSWAP |
3575 MEM_CGROUP_RECLAIM_SHRINK);
3576 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3577 /* Usage is reduced ? */
3578 if (curusage >= oldusage)
3581 oldusage = curusage;
3583 if (!ret && enlarge)
3584 memcg_oom_recover(memcg);
3588 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3590 unsigned long *total_scanned)
3592 unsigned long nr_reclaimed = 0;
3593 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3594 unsigned long reclaimed;
3596 struct mem_cgroup_tree_per_zone *mctz;
3597 unsigned long long excess;
3598 unsigned long nr_scanned;
3603 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3605 * This loop can run a while, specially if mem_cgroup's continuously
3606 * keep exceeding their soft limit and putting the system under
3613 mz = mem_cgroup_largest_soft_limit_node(mctz);
3618 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
3619 gfp_mask, &nr_scanned);
3620 nr_reclaimed += reclaimed;
3621 *total_scanned += nr_scanned;
3622 spin_lock(&mctz->lock);
3625 * If we failed to reclaim anything from this memory cgroup
3626 * it is time to move on to the next cgroup
3632 * Loop until we find yet another one.
3634 * By the time we get the soft_limit lock
3635 * again, someone might have aded the
3636 * group back on the RB tree. Iterate to
3637 * make sure we get a different mem.
3638 * mem_cgroup_largest_soft_limit_node returns
3639 * NULL if no other cgroup is present on
3643 __mem_cgroup_largest_soft_limit_node(mctz);
3645 css_put(&next_mz->memcg->css);
3646 else /* next_mz == NULL or other memcg */
3650 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
3651 excess = res_counter_soft_limit_excess(&mz->memcg->res);
3653 * One school of thought says that we should not add
3654 * back the node to the tree if reclaim returns 0.
3655 * But our reclaim could return 0, simply because due
3656 * to priority we are exposing a smaller subset of
3657 * memory to reclaim from. Consider this as a longer
3660 /* If excess == 0, no tree ops */
3661 __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess);
3662 spin_unlock(&mctz->lock);
3663 css_put(&mz->memcg->css);
3666 * Could not reclaim anything and there are no more
3667 * mem cgroups to try or we seem to be looping without
3668 * reclaiming anything.
3670 if (!nr_reclaimed &&
3672 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3674 } while (!nr_reclaimed);
3676 css_put(&next_mz->memcg->css);
3677 return nr_reclaimed;
3681 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
3682 * reclaim the pages page themselves - it just removes the page_cgroups.
3683 * Returns true if some page_cgroups were not freed, indicating that the caller
3684 * must retry this operation.
3686 static bool mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
3687 int node, int zid, enum lru_list lru)
3689 struct mem_cgroup_per_zone *mz;
3690 unsigned long flags, loop;
3691 struct list_head *list;
3695 zone = &NODE_DATA(node)->node_zones[zid];
3696 mz = mem_cgroup_zoneinfo(memcg, node, zid);
3697 list = &mz->lruvec.lists[lru];
3699 loop = mz->lru_size[lru];
3700 /* give some margin against EBUSY etc...*/
3704 struct page_cgroup *pc;
3707 spin_lock_irqsave(&zone->lru_lock, flags);
3708 if (list_empty(list)) {
3709 spin_unlock_irqrestore(&zone->lru_lock, flags);
3712 page = list_entry(list->prev, struct page, lru);
3714 list_move(&page->lru, list);
3716 spin_unlock_irqrestore(&zone->lru_lock, flags);
3719 spin_unlock_irqrestore(&zone->lru_lock, flags);
3721 pc = lookup_page_cgroup(page);
3723 if (mem_cgroup_move_parent(page, pc, memcg)) {
3724 /* found lock contention or "pc" is obsolete. */
3730 return !list_empty(list);
3734 * make mem_cgroup's charge to be 0 if there is no task.
3735 * This enables deleting this mem_cgroup.
3737 static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
3740 int node, zid, shrink;
3741 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3742 struct cgroup *cgrp = memcg->css.cgroup;
3744 css_get(&memcg->css);
3747 /* should free all ? */
3753 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3755 /* This is for making all *used* pages to be on LRU. */
3756 lru_add_drain_all();
3757 drain_all_stock_sync(memcg);
3759 mem_cgroup_start_move(memcg);
3760 for_each_node_state(node, N_HIGH_MEMORY) {
3761 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3764 ret = mem_cgroup_force_empty_list(memcg,
3773 mem_cgroup_end_move(memcg);
3774 memcg_oom_recover(memcg);
3776 /* "ret" should also be checked to ensure all lists are empty. */
3777 } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
3779 css_put(&memcg->css);
3783 /* returns EBUSY if there is a task or if we come here twice. */
3784 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3788 /* we call try-to-free pages for make this cgroup empty */
3789 lru_add_drain_all();
3790 /* try to free all pages in this cgroup */
3792 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
3795 if (signal_pending(current)) {
3799 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
3803 /* maybe some writeback is necessary */
3804 congestion_wait(BLK_RW_ASYNC, HZ/10);
3809 /* try move_account...there may be some *locked* pages. */
3813 static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3815 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3819 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3821 return mem_cgroup_from_cont(cont)->use_hierarchy;
3824 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3828 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3829 struct cgroup *parent = cont->parent;
3830 struct mem_cgroup *parent_memcg = NULL;
3833 parent_memcg = mem_cgroup_from_cont(parent);
3837 if (memcg->use_hierarchy == val)
3841 * If parent's use_hierarchy is set, we can't make any modifications
3842 * in the child subtrees. If it is unset, then the change can
3843 * occur, provided the current cgroup has no children.
3845 * For the root cgroup, parent_mem is NULL, we allow value to be
3846 * set if there are no children.
3848 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3849 (val == 1 || val == 0)) {
3850 if (list_empty(&cont->children))
3851 memcg->use_hierarchy = val;
3864 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
3865 enum mem_cgroup_stat_index idx)
3867 struct mem_cgroup *iter;
3870 /* Per-cpu values can be negative, use a signed accumulator */
3871 for_each_mem_cgroup_tree(iter, memcg)
3872 val += mem_cgroup_read_stat(iter, idx);
3874 if (val < 0) /* race ? */
3879 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3883 if (!mem_cgroup_is_root(memcg)) {
3885 return res_counter_read_u64(&memcg->res, RES_USAGE);
3887 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
3890 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
3891 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
3894 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAP);
3896 return val << PAGE_SHIFT;
3899 static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
3900 struct file *file, char __user *buf,
3901 size_t nbytes, loff_t *ppos)
3903 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3906 int type, name, len;
3908 type = MEMFILE_TYPE(cft->private);
3909 name = MEMFILE_ATTR(cft->private);
3911 if (!do_swap_account && type == _MEMSWAP)
3916 if (name == RES_USAGE)
3917 val = mem_cgroup_usage(memcg, false);
3919 val = res_counter_read_u64(&memcg->res, name);
3922 if (name == RES_USAGE)
3923 val = mem_cgroup_usage(memcg, true);
3925 val = res_counter_read_u64(&memcg->memsw, name);
3931 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
3932 return simple_read_from_buffer(buf, nbytes, ppos, str, len);
3935 * The user of this function is...
3938 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3941 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3943 unsigned long long val;
3946 type = MEMFILE_TYPE(cft->private);
3947 name = MEMFILE_ATTR(cft->private);
3949 if (!do_swap_account && type == _MEMSWAP)
3954 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3958 /* This function does all necessary parse...reuse it */
3959 ret = res_counter_memparse_write_strategy(buffer, &val);
3963 ret = mem_cgroup_resize_limit(memcg, val);
3965 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3967 case RES_SOFT_LIMIT:
3968 ret = res_counter_memparse_write_strategy(buffer, &val);
3972 * For memsw, soft limits are hard to implement in terms
3973 * of semantics, for now, we support soft limits for
3974 * control without swap
3977 ret = res_counter_set_soft_limit(&memcg->res, val);
3982 ret = -EINVAL; /* should be BUG() ? */
3988 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3989 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3991 struct cgroup *cgroup;
3992 unsigned long long min_limit, min_memsw_limit, tmp;
3994 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3995 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3996 cgroup = memcg->css.cgroup;
3997 if (!memcg->use_hierarchy)
4000 while (cgroup->parent) {
4001 cgroup = cgroup->parent;
4002 memcg = mem_cgroup_from_cont(cgroup);
4003 if (!memcg->use_hierarchy)
4005 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
4006 min_limit = min(min_limit, tmp);
4007 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
4008 min_memsw_limit = min(min_memsw_limit, tmp);
4011 *mem_limit = min_limit;
4012 *memsw_limit = min_memsw_limit;
4015 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
4017 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4020 type = MEMFILE_TYPE(event);
4021 name = MEMFILE_ATTR(event);
4023 if (!do_swap_account && type == _MEMSWAP)
4029 res_counter_reset_max(&memcg->res);
4031 res_counter_reset_max(&memcg->memsw);
4035 res_counter_reset_failcnt(&memcg->res);
4037 res_counter_reset_failcnt(&memcg->memsw);
4044 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
4047 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
4051 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4052 struct cftype *cft, u64 val)
4054 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4056 if (val >= (1 << NR_MOVE_TYPE))
4059 * We check this value several times in both in can_attach() and
4060 * attach(), so we need cgroup lock to prevent this value from being
4064 memcg->move_charge_at_immigrate = val;
4070 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4071 struct cftype *cft, u64 val)
4078 static int memcg_numa_stat_show(struct cgroup *cont, struct cftype *cft,
4082 unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
4083 unsigned long node_nr;
4084 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4086 total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL);
4087 seq_printf(m, "total=%lu", total_nr);
4088 for_each_node_state(nid, N_HIGH_MEMORY) {
4089 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL);
4090 seq_printf(m, " N%d=%lu", nid, node_nr);
4094 file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE);
4095 seq_printf(m, "file=%lu", file_nr);
4096 for_each_node_state(nid, N_HIGH_MEMORY) {
4097 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4099 seq_printf(m, " N%d=%lu", nid, node_nr);
4103 anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON);
4104 seq_printf(m, "anon=%lu", anon_nr);
4105 for_each_node_state(nid, N_HIGH_MEMORY) {
4106 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4108 seq_printf(m, " N%d=%lu", nid, node_nr);
4112 unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
4113 seq_printf(m, "unevictable=%lu", unevictable_nr);
4114 for_each_node_state(nid, N_HIGH_MEMORY) {
4115 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4116 BIT(LRU_UNEVICTABLE));
4117 seq_printf(m, " N%d=%lu", nid, node_nr);
4122 #endif /* CONFIG_NUMA */
4124 static const char * const mem_cgroup_lru_names[] = {
4132 static inline void mem_cgroup_lru_names_not_uptodate(void)
4134 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
4137 static int memcg_stat_show(struct cgroup *cont, struct cftype *cft,
4140 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4141 struct mem_cgroup *mi;
4144 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4145 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
4147 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
4148 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
4151 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
4152 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
4153 mem_cgroup_read_events(memcg, i));
4155 for (i = 0; i < NR_LRU_LISTS; i++)
4156 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
4157 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
4159 /* Hierarchical information */
4161 unsigned long long limit, memsw_limit;
4162 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
4163 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
4164 if (do_swap_account)
4165 seq_printf(m, "hierarchical_memsw_limit %llu\n",
4169 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4172 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
4174 for_each_mem_cgroup_tree(mi, memcg)
4175 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
4176 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
4179 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
4180 unsigned long long val = 0;
4182 for_each_mem_cgroup_tree(mi, memcg)
4183 val += mem_cgroup_read_events(mi, i);
4184 seq_printf(m, "total_%s %llu\n",
4185 mem_cgroup_events_names[i], val);
4188 for (i = 0; i < NR_LRU_LISTS; i++) {
4189 unsigned long long val = 0;
4191 for_each_mem_cgroup_tree(mi, memcg)
4192 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
4193 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
4196 #ifdef CONFIG_DEBUG_VM
4199 struct mem_cgroup_per_zone *mz;
4200 struct zone_reclaim_stat *rstat;
4201 unsigned long recent_rotated[2] = {0, 0};
4202 unsigned long recent_scanned[2] = {0, 0};
4204 for_each_online_node(nid)
4205 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4206 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
4207 rstat = &mz->lruvec.reclaim_stat;
4209 recent_rotated[0] += rstat->recent_rotated[0];
4210 recent_rotated[1] += rstat->recent_rotated[1];
4211 recent_scanned[0] += rstat->recent_scanned[0];
4212 recent_scanned[1] += rstat->recent_scanned[1];
4214 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
4215 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
4216 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
4217 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
4224 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
4226 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4228 return mem_cgroup_swappiness(memcg);
4231 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
4234 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4235 struct mem_cgroup *parent;
4240 if (cgrp->parent == NULL)
4243 parent = mem_cgroup_from_cont(cgrp->parent);
4247 /* If under hierarchy, only empty-root can set this value */
4248 if ((parent->use_hierarchy) ||
4249 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4254 memcg->swappiness = val;
4261 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4263 struct mem_cgroup_threshold_ary *t;
4269 t = rcu_dereference(memcg->thresholds.primary);
4271 t = rcu_dereference(memcg->memsw_thresholds.primary);
4276 usage = mem_cgroup_usage(memcg, swap);
4279 * current_threshold points to threshold just below or equal to usage.
4280 * If it's not true, a threshold was crossed after last
4281 * call of __mem_cgroup_threshold().
4283 i = t->current_threshold;
4286 * Iterate backward over array of thresholds starting from
4287 * current_threshold and check if a threshold is crossed.
4288 * If none of thresholds below usage is crossed, we read
4289 * only one element of the array here.
4291 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4292 eventfd_signal(t->entries[i].eventfd, 1);
4294 /* i = current_threshold + 1 */
4298 * Iterate forward over array of thresholds starting from
4299 * current_threshold+1 and check if a threshold is crossed.
4300 * If none of thresholds above usage is crossed, we read
4301 * only one element of the array here.
4303 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4304 eventfd_signal(t->entries[i].eventfd, 1);
4306 /* Update current_threshold */
4307 t->current_threshold = i - 1;
4312 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4315 __mem_cgroup_threshold(memcg, false);
4316 if (do_swap_account)
4317 __mem_cgroup_threshold(memcg, true);
4319 memcg = parent_mem_cgroup(memcg);
4323 static int compare_thresholds(const void *a, const void *b)
4325 const struct mem_cgroup_threshold *_a = a;
4326 const struct mem_cgroup_threshold *_b = b;
4328 return _a->threshold - _b->threshold;
4331 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4333 struct mem_cgroup_eventfd_list *ev;
4335 list_for_each_entry(ev, &memcg->oom_notify, list)
4336 eventfd_signal(ev->eventfd, 1);
4340 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4342 struct mem_cgroup *iter;
4344 for_each_mem_cgroup_tree(iter, memcg)
4345 mem_cgroup_oom_notify_cb(iter);
4348 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
4349 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4351 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4352 struct mem_cgroup_thresholds *thresholds;
4353 struct mem_cgroup_threshold_ary *new;
4354 int type = MEMFILE_TYPE(cft->private);
4355 u64 threshold, usage;
4358 ret = res_counter_memparse_write_strategy(args, &threshold);
4362 mutex_lock(&memcg->thresholds_lock);
4365 thresholds = &memcg->thresholds;
4366 else if (type == _MEMSWAP)
4367 thresholds = &memcg->memsw_thresholds;
4371 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4373 /* Check if a threshold crossed before adding a new one */
4374 if (thresholds->primary)
4375 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4377 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4379 /* Allocate memory for new array of thresholds */
4380 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4388 /* Copy thresholds (if any) to new array */
4389 if (thresholds->primary) {
4390 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4391 sizeof(struct mem_cgroup_threshold));
4394 /* Add new threshold */
4395 new->entries[size - 1].eventfd = eventfd;
4396 new->entries[size - 1].threshold = threshold;
4398 /* Sort thresholds. Registering of new threshold isn't time-critical */
4399 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4400 compare_thresholds, NULL);
4402 /* Find current threshold */
4403 new->current_threshold = -1;
4404 for (i = 0; i < size; i++) {
4405 if (new->entries[i].threshold <= usage) {
4407 * new->current_threshold will not be used until
4408 * rcu_assign_pointer(), so it's safe to increment
4411 ++new->current_threshold;
4416 /* Free old spare buffer and save old primary buffer as spare */
4417 kfree(thresholds->spare);
4418 thresholds->spare = thresholds->primary;
4420 rcu_assign_pointer(thresholds->primary, new);
4422 /* To be sure that nobody uses thresholds */
4426 mutex_unlock(&memcg->thresholds_lock);
4431 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4432 struct cftype *cft, struct eventfd_ctx *eventfd)
4434 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4435 struct mem_cgroup_thresholds *thresholds;
4436 struct mem_cgroup_threshold_ary *new;
4437 int type = MEMFILE_TYPE(cft->private);
4441 mutex_lock(&memcg->thresholds_lock);
4443 thresholds = &memcg->thresholds;
4444 else if (type == _MEMSWAP)
4445 thresholds = &memcg->memsw_thresholds;
4449 if (!thresholds->primary)
4452 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4454 /* Check if a threshold crossed before removing */
4455 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4457 /* Calculate new number of threshold */
4459 for (i = 0; i < thresholds->primary->size; i++) {
4460 if (thresholds->primary->entries[i].eventfd != eventfd)
4464 new = thresholds->spare;
4466 /* Set thresholds array to NULL if we don't have thresholds */
4475 /* Copy thresholds and find current threshold */
4476 new->current_threshold = -1;
4477 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4478 if (thresholds->primary->entries[i].eventfd == eventfd)
4481 new->entries[j] = thresholds->primary->entries[i];
4482 if (new->entries[j].threshold <= usage) {
4484 * new->current_threshold will not be used
4485 * until rcu_assign_pointer(), so it's safe to increment
4488 ++new->current_threshold;
4494 /* Swap primary and spare array */
4495 thresholds->spare = thresholds->primary;
4496 /* If all events are unregistered, free the spare array */
4498 kfree(thresholds->spare);
4499 thresholds->spare = NULL;
4502 rcu_assign_pointer(thresholds->primary, new);
4504 /* To be sure that nobody uses thresholds */
4507 mutex_unlock(&memcg->thresholds_lock);
4510 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4511 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4513 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4514 struct mem_cgroup_eventfd_list *event;
4515 int type = MEMFILE_TYPE(cft->private);
4517 BUG_ON(type != _OOM_TYPE);
4518 event = kmalloc(sizeof(*event), GFP_KERNEL);
4522 spin_lock(&memcg_oom_lock);
4524 event->eventfd = eventfd;
4525 list_add(&event->list, &memcg->oom_notify);
4527 /* already in OOM ? */
4528 if (atomic_read(&memcg->under_oom))
4529 eventfd_signal(eventfd, 1);
4530 spin_unlock(&memcg_oom_lock);
4535 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4536 struct cftype *cft, struct eventfd_ctx *eventfd)
4538 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4539 struct mem_cgroup_eventfd_list *ev, *tmp;
4540 int type = MEMFILE_TYPE(cft->private);
4542 BUG_ON(type != _OOM_TYPE);
4544 spin_lock(&memcg_oom_lock);
4546 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4547 if (ev->eventfd == eventfd) {
4548 list_del(&ev->list);
4553 spin_unlock(&memcg_oom_lock);
4556 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4557 struct cftype *cft, struct cgroup_map_cb *cb)
4559 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4561 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
4563 if (atomic_read(&memcg->under_oom))
4564 cb->fill(cb, "under_oom", 1);
4566 cb->fill(cb, "under_oom", 0);
4570 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4571 struct cftype *cft, u64 val)
4573 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4574 struct mem_cgroup *parent;
4576 /* cannot set to root cgroup and only 0 and 1 are allowed */
4577 if (!cgrp->parent || !((val == 0) || (val == 1)))
4580 parent = mem_cgroup_from_cont(cgrp->parent);
4583 /* oom-kill-disable is a flag for subhierarchy. */
4584 if ((parent->use_hierarchy) ||
4585 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4589 memcg->oom_kill_disable = val;
4591 memcg_oom_recover(memcg);
4596 #ifdef CONFIG_MEMCG_KMEM
4597 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4599 return mem_cgroup_sockets_init(memcg, ss);
4602 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
4604 mem_cgroup_sockets_destroy(memcg);
4607 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4612 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
4617 static struct cftype mem_cgroup_files[] = {
4619 .name = "usage_in_bytes",
4620 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4621 .read = mem_cgroup_read,
4622 .register_event = mem_cgroup_usage_register_event,
4623 .unregister_event = mem_cgroup_usage_unregister_event,
4626 .name = "max_usage_in_bytes",
4627 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4628 .trigger = mem_cgroup_reset,
4629 .read = mem_cgroup_read,
4632 .name = "limit_in_bytes",
4633 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4634 .write_string = mem_cgroup_write,
4635 .read = mem_cgroup_read,
4638 .name = "soft_limit_in_bytes",
4639 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4640 .write_string = mem_cgroup_write,
4641 .read = mem_cgroup_read,
4645 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4646 .trigger = mem_cgroup_reset,
4647 .read = mem_cgroup_read,
4651 .read_seq_string = memcg_stat_show,
4654 .name = "force_empty",
4655 .trigger = mem_cgroup_force_empty_write,
4658 .name = "use_hierarchy",
4659 .write_u64 = mem_cgroup_hierarchy_write,
4660 .read_u64 = mem_cgroup_hierarchy_read,
4663 .name = "swappiness",
4664 .read_u64 = mem_cgroup_swappiness_read,
4665 .write_u64 = mem_cgroup_swappiness_write,
4668 .name = "move_charge_at_immigrate",
4669 .read_u64 = mem_cgroup_move_charge_read,
4670 .write_u64 = mem_cgroup_move_charge_write,
4673 .name = "oom_control",
4674 .read_map = mem_cgroup_oom_control_read,
4675 .write_u64 = mem_cgroup_oom_control_write,
4676 .register_event = mem_cgroup_oom_register_event,
4677 .unregister_event = mem_cgroup_oom_unregister_event,
4678 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4682 .name = "numa_stat",
4683 .read_seq_string = memcg_numa_stat_show,
4686 #ifdef CONFIG_MEMCG_SWAP
4688 .name = "memsw.usage_in_bytes",
4689 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4690 .read = mem_cgroup_read,
4691 .register_event = mem_cgroup_usage_register_event,
4692 .unregister_event = mem_cgroup_usage_unregister_event,
4695 .name = "memsw.max_usage_in_bytes",
4696 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4697 .trigger = mem_cgroup_reset,
4698 .read = mem_cgroup_read,
4701 .name = "memsw.limit_in_bytes",
4702 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4703 .write_string = mem_cgroup_write,
4704 .read = mem_cgroup_read,
4707 .name = "memsw.failcnt",
4708 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4709 .trigger = mem_cgroup_reset,
4710 .read = mem_cgroup_read,
4713 { }, /* terminate */
4716 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4718 struct mem_cgroup_per_node *pn;
4719 struct mem_cgroup_per_zone *mz;
4720 int zone, tmp = node;
4722 * This routine is called against possible nodes.
4723 * But it's BUG to call kmalloc() against offline node.
4725 * TODO: this routine can waste much memory for nodes which will
4726 * never be onlined. It's better to use memory hotplug callback
4729 if (!node_state(node, N_NORMAL_MEMORY))
4731 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4735 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4736 mz = &pn->zoneinfo[zone];
4737 lruvec_init(&mz->lruvec, &NODE_DATA(node)->node_zones[zone]);
4738 mz->usage_in_excess = 0;
4739 mz->on_tree = false;
4742 memcg->info.nodeinfo[node] = pn;
4746 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4748 kfree(memcg->info.nodeinfo[node]);
4751 static struct mem_cgroup *mem_cgroup_alloc(void)
4753 struct mem_cgroup *memcg;
4754 int size = sizeof(struct mem_cgroup);
4756 /* Can be very big if MAX_NUMNODES is very big */
4757 if (size < PAGE_SIZE)
4758 memcg = kzalloc(size, GFP_KERNEL);
4760 memcg = vzalloc(size);
4765 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4768 spin_lock_init(&memcg->pcp_counter_lock);
4772 if (size < PAGE_SIZE)
4780 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
4781 * but in process context. The work_freeing structure is overlaid
4782 * on the rcu_freeing structure, which itself is overlaid on memsw.
4784 static void free_work(struct work_struct *work)
4786 struct mem_cgroup *memcg;
4787 int size = sizeof(struct mem_cgroup);
4789 memcg = container_of(work, struct mem_cgroup, work_freeing);
4791 * We need to make sure that (at least for now), the jump label
4792 * destruction code runs outside of the cgroup lock. This is because
4793 * get_online_cpus(), which is called from the static_branch update,
4794 * can't be called inside the cgroup_lock. cpusets are the ones
4795 * enforcing this dependency, so if they ever change, we might as well.
4797 * schedule_work() will guarantee this happens. Be careful if you need
4798 * to move this code around, and make sure it is outside
4801 disarm_sock_keys(memcg);
4802 if (size < PAGE_SIZE)
4808 static void free_rcu(struct rcu_head *rcu_head)
4810 struct mem_cgroup *memcg;
4812 memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing);
4813 INIT_WORK(&memcg->work_freeing, free_work);
4814 schedule_work(&memcg->work_freeing);
4818 * At destroying mem_cgroup, references from swap_cgroup can remain.
4819 * (scanning all at force_empty is too costly...)
4821 * Instead of clearing all references at force_empty, we remember
4822 * the number of reference from swap_cgroup and free mem_cgroup when
4823 * it goes down to 0.
4825 * Removal of cgroup itself succeeds regardless of refs from swap.
4828 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4832 mem_cgroup_remove_from_trees(memcg);
4833 free_css_id(&mem_cgroup_subsys, &memcg->css);
4836 free_mem_cgroup_per_zone_info(memcg, node);
4838 free_percpu(memcg->stat);
4839 call_rcu(&memcg->rcu_freeing, free_rcu);
4842 static void mem_cgroup_get(struct mem_cgroup *memcg)
4844 atomic_inc(&memcg->refcnt);
4847 static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
4849 if (atomic_sub_and_test(count, &memcg->refcnt)) {
4850 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4851 __mem_cgroup_free(memcg);
4853 mem_cgroup_put(parent);
4857 static void mem_cgroup_put(struct mem_cgroup *memcg)
4859 __mem_cgroup_put(memcg, 1);
4863 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4865 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
4867 if (!memcg->res.parent)
4869 return mem_cgroup_from_res_counter(memcg->res.parent, res);
4871 EXPORT_SYMBOL(parent_mem_cgroup);
4873 #ifdef CONFIG_MEMCG_SWAP
4874 static void __init enable_swap_cgroup(void)
4876 if (!mem_cgroup_disabled() && really_do_swap_account)
4877 do_swap_account = 1;
4880 static void __init enable_swap_cgroup(void)
4885 static int mem_cgroup_soft_limit_tree_init(void)
4887 struct mem_cgroup_tree_per_node *rtpn;
4888 struct mem_cgroup_tree_per_zone *rtpz;
4889 int tmp, node, zone;
4891 for_each_node(node) {
4893 if (!node_state(node, N_NORMAL_MEMORY))
4895 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4899 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4901 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4902 rtpz = &rtpn->rb_tree_per_zone[zone];
4903 rtpz->rb_root = RB_ROOT;
4904 spin_lock_init(&rtpz->lock);
4910 for_each_node(node) {
4911 if (!soft_limit_tree.rb_tree_per_node[node])
4913 kfree(soft_limit_tree.rb_tree_per_node[node]);
4914 soft_limit_tree.rb_tree_per_node[node] = NULL;
4920 static struct cgroup_subsys_state * __ref
4921 mem_cgroup_create(struct cgroup *cont)
4923 struct mem_cgroup *memcg, *parent;
4924 long error = -ENOMEM;
4927 memcg = mem_cgroup_alloc();
4929 return ERR_PTR(error);
4932 if (alloc_mem_cgroup_per_zone_info(memcg, node))
4936 if (cont->parent == NULL) {
4938 enable_swap_cgroup();
4940 if (mem_cgroup_soft_limit_tree_init())
4942 root_mem_cgroup = memcg;
4943 for_each_possible_cpu(cpu) {
4944 struct memcg_stock_pcp *stock =
4945 &per_cpu(memcg_stock, cpu);
4946 INIT_WORK(&stock->work, drain_local_stock);
4948 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4950 parent = mem_cgroup_from_cont(cont->parent);
4951 memcg->use_hierarchy = parent->use_hierarchy;
4952 memcg->oom_kill_disable = parent->oom_kill_disable;
4955 if (parent && parent->use_hierarchy) {
4956 res_counter_init(&memcg->res, &parent->res);
4957 res_counter_init(&memcg->memsw, &parent->memsw);
4959 * We increment refcnt of the parent to ensure that we can
4960 * safely access it on res_counter_charge/uncharge.
4961 * This refcnt will be decremented when freeing this
4962 * mem_cgroup(see mem_cgroup_put).
4964 mem_cgroup_get(parent);
4966 res_counter_init(&memcg->res, NULL);
4967 res_counter_init(&memcg->memsw, NULL);
4969 memcg->last_scanned_node = MAX_NUMNODES;
4970 INIT_LIST_HEAD(&memcg->oom_notify);
4973 memcg->swappiness = mem_cgroup_swappiness(parent);
4974 atomic_set(&memcg->refcnt, 1);
4975 memcg->move_charge_at_immigrate = 0;
4976 mutex_init(&memcg->thresholds_lock);
4977 spin_lock_init(&memcg->move_lock);
4979 error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
4982 * We call put now because our (and parent's) refcnts
4983 * are already in place. mem_cgroup_put() will internally
4984 * call __mem_cgroup_free, so return directly
4986 mem_cgroup_put(memcg);
4987 return ERR_PTR(error);
4991 __mem_cgroup_free(memcg);
4992 return ERR_PTR(error);
4995 static int mem_cgroup_pre_destroy(struct cgroup *cont)
4997 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4999 return mem_cgroup_force_empty(memcg, false);
5002 static void mem_cgroup_destroy(struct cgroup *cont)
5004 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
5006 kmem_cgroup_destroy(memcg);
5008 mem_cgroup_put(memcg);
5012 /* Handlers for move charge at task migration. */
5013 #define PRECHARGE_COUNT_AT_ONCE 256
5014 static int mem_cgroup_do_precharge(unsigned long count)
5017 int batch_count = PRECHARGE_COUNT_AT_ONCE;
5018 struct mem_cgroup *memcg = mc.to;
5020 if (mem_cgroup_is_root(memcg)) {
5021 mc.precharge += count;
5022 /* we don't need css_get for root */
5025 /* try to charge at once */
5027 struct res_counter *dummy;
5029 * "memcg" cannot be under rmdir() because we've already checked
5030 * by cgroup_lock_live_cgroup() that it is not removed and we
5031 * are still under the same cgroup_mutex. So we can postpone
5034 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
5036 if (do_swap_account && res_counter_charge(&memcg->memsw,
5037 PAGE_SIZE * count, &dummy)) {
5038 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
5041 mc.precharge += count;
5045 /* fall back to one by one charge */
5047 if (signal_pending(current)) {
5051 if (!batch_count--) {
5052 batch_count = PRECHARGE_COUNT_AT_ONCE;
5055 ret = __mem_cgroup_try_charge(NULL,
5056 GFP_KERNEL, 1, &memcg, false);
5058 /* mem_cgroup_clear_mc() will do uncharge later */
5066 * get_mctgt_type - get target type of moving charge
5067 * @vma: the vma the pte to be checked belongs
5068 * @addr: the address corresponding to the pte to be checked
5069 * @ptent: the pte to be checked
5070 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5073 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5074 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5075 * move charge. if @target is not NULL, the page is stored in target->page
5076 * with extra refcnt got(Callers should handle it).
5077 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5078 * target for charge migration. if @target is not NULL, the entry is stored
5081 * Called with pte lock held.
5088 enum mc_target_type {
5094 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5095 unsigned long addr, pte_t ptent)
5097 struct page *page = vm_normal_page(vma, addr, ptent);
5099 if (!page || !page_mapped(page))
5101 if (PageAnon(page)) {
5102 /* we don't move shared anon */
5105 } else if (!move_file())
5106 /* we ignore mapcount for file pages */
5108 if (!get_page_unless_zero(page))
5115 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5116 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5118 struct page *page = NULL;
5119 swp_entry_t ent = pte_to_swp_entry(ptent);
5121 if (!move_anon() || non_swap_entry(ent))
5124 * Because lookup_swap_cache() updates some statistics counter,
5125 * we call find_get_page() with swapper_space directly.
5127 page = find_get_page(&swapper_space, ent.val);
5128 if (do_swap_account)
5129 entry->val = ent.val;
5134 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5135 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5141 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5142 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5144 struct page *page = NULL;
5145 struct address_space *mapping;
5148 if (!vma->vm_file) /* anonymous vma */
5153 mapping = vma->vm_file->f_mapping;
5154 if (pte_none(ptent))
5155 pgoff = linear_page_index(vma, addr);
5156 else /* pte_file(ptent) is true */
5157 pgoff = pte_to_pgoff(ptent);
5159 /* page is moved even if it's not RSS of this task(page-faulted). */
5160 page = find_get_page(mapping, pgoff);
5163 /* shmem/tmpfs may report page out on swap: account for that too. */
5164 if (radix_tree_exceptional_entry(page)) {
5165 swp_entry_t swap = radix_to_swp_entry(page);
5166 if (do_swap_account)
5168 page = find_get_page(&swapper_space, swap.val);
5174 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5175 unsigned long addr, pte_t ptent, union mc_target *target)
5177 struct page *page = NULL;
5178 struct page_cgroup *pc;
5179 enum mc_target_type ret = MC_TARGET_NONE;
5180 swp_entry_t ent = { .val = 0 };
5182 if (pte_present(ptent))
5183 page = mc_handle_present_pte(vma, addr, ptent);
5184 else if (is_swap_pte(ptent))
5185 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5186 else if (pte_none(ptent) || pte_file(ptent))
5187 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5189 if (!page && !ent.val)
5192 pc = lookup_page_cgroup(page);
5194 * Do only loose check w/o page_cgroup lock.
5195 * mem_cgroup_move_account() checks the pc is valid or not under
5198 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5199 ret = MC_TARGET_PAGE;
5201 target->page = page;
5203 if (!ret || !target)
5206 /* There is a swap entry and a page doesn't exist or isn't charged */
5207 if (ent.val && !ret &&
5208 css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
5209 ret = MC_TARGET_SWAP;
5216 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5218 * We don't consider swapping or file mapped pages because THP does not
5219 * support them for now.
5220 * Caller should make sure that pmd_trans_huge(pmd) is true.
5222 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5223 unsigned long addr, pmd_t pmd, union mc_target *target)
5225 struct page *page = NULL;
5226 struct page_cgroup *pc;
5227 enum mc_target_type ret = MC_TARGET_NONE;
5229 page = pmd_page(pmd);
5230 VM_BUG_ON(!page || !PageHead(page));
5233 pc = lookup_page_cgroup(page);
5234 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5235 ret = MC_TARGET_PAGE;
5238 target->page = page;
5244 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5245 unsigned long addr, pmd_t pmd, union mc_target *target)
5247 return MC_TARGET_NONE;
5251 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5252 unsigned long addr, unsigned long end,
5253 struct mm_walk *walk)
5255 struct vm_area_struct *vma = walk->private;
5259 if (pmd_trans_huge_lock(pmd, vma) == 1) {
5260 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5261 mc.precharge += HPAGE_PMD_NR;
5262 spin_unlock(&vma->vm_mm->page_table_lock);
5266 if (pmd_trans_unstable(pmd))
5268 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5269 for (; addr != end; pte++, addr += PAGE_SIZE)
5270 if (get_mctgt_type(vma, addr, *pte, NULL))
5271 mc.precharge++; /* increment precharge temporarily */
5272 pte_unmap_unlock(pte - 1, ptl);
5278 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5280 unsigned long precharge;
5281 struct vm_area_struct *vma;
5283 down_read(&mm->mmap_sem);
5284 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5285 struct mm_walk mem_cgroup_count_precharge_walk = {
5286 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5290 if (is_vm_hugetlb_page(vma))
5292 walk_page_range(vma->vm_start, vma->vm_end,
5293 &mem_cgroup_count_precharge_walk);
5295 up_read(&mm->mmap_sem);
5297 precharge = mc.precharge;
5303 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5305 unsigned long precharge = mem_cgroup_count_precharge(mm);
5307 VM_BUG_ON(mc.moving_task);
5308 mc.moving_task = current;
5309 return mem_cgroup_do_precharge(precharge);
5312 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5313 static void __mem_cgroup_clear_mc(void)
5315 struct mem_cgroup *from = mc.from;
5316 struct mem_cgroup *to = mc.to;
5318 /* we must uncharge all the leftover precharges from mc.to */
5320 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
5324 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5325 * we must uncharge here.
5327 if (mc.moved_charge) {
5328 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
5329 mc.moved_charge = 0;
5331 /* we must fixup refcnts and charges */
5332 if (mc.moved_swap) {
5333 /* uncharge swap account from the old cgroup */
5334 if (!mem_cgroup_is_root(mc.from))
5335 res_counter_uncharge(&mc.from->memsw,
5336 PAGE_SIZE * mc.moved_swap);
5337 __mem_cgroup_put(mc.from, mc.moved_swap);
5339 if (!mem_cgroup_is_root(mc.to)) {
5341 * we charged both to->res and to->memsw, so we should
5344 res_counter_uncharge(&mc.to->res,
5345 PAGE_SIZE * mc.moved_swap);
5347 /* we've already done mem_cgroup_get(mc.to) */
5350 memcg_oom_recover(from);
5351 memcg_oom_recover(to);
5352 wake_up_all(&mc.waitq);
5355 static void mem_cgroup_clear_mc(void)
5357 struct mem_cgroup *from = mc.from;
5360 * we must clear moving_task before waking up waiters at the end of
5363 mc.moving_task = NULL;
5364 __mem_cgroup_clear_mc();
5365 spin_lock(&mc.lock);
5368 spin_unlock(&mc.lock);
5369 mem_cgroup_end_move(from);
5372 static int mem_cgroup_can_attach(struct cgroup *cgroup,
5373 struct cgroup_taskset *tset)
5375 struct task_struct *p = cgroup_taskset_first(tset);
5377 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);
5379 if (memcg->move_charge_at_immigrate) {
5380 struct mm_struct *mm;
5381 struct mem_cgroup *from = mem_cgroup_from_task(p);
5383 VM_BUG_ON(from == memcg);
5385 mm = get_task_mm(p);
5388 /* We move charges only when we move a owner of the mm */
5389 if (mm->owner == p) {
5392 VM_BUG_ON(mc.precharge);
5393 VM_BUG_ON(mc.moved_charge);
5394 VM_BUG_ON(mc.moved_swap);
5395 mem_cgroup_start_move(from);
5396 spin_lock(&mc.lock);
5399 spin_unlock(&mc.lock);
5400 /* We set mc.moving_task later */
5402 ret = mem_cgroup_precharge_mc(mm);
5404 mem_cgroup_clear_mc();
5411 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
5412 struct cgroup_taskset *tset)
5414 mem_cgroup_clear_mc();
5417 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5418 unsigned long addr, unsigned long end,
5419 struct mm_walk *walk)
5422 struct vm_area_struct *vma = walk->private;
5425 enum mc_target_type target_type;
5426 union mc_target target;
5428 struct page_cgroup *pc;
5431 * We don't take compound_lock() here but no race with splitting thp
5433 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5434 * under splitting, which means there's no concurrent thp split,
5435 * - if another thread runs into split_huge_page() just after we
5436 * entered this if-block, the thread must wait for page table lock
5437 * to be unlocked in __split_huge_page_splitting(), where the main
5438 * part of thp split is not executed yet.
5440 if (pmd_trans_huge_lock(pmd, vma) == 1) {
5441 if (mc.precharge < HPAGE_PMD_NR) {
5442 spin_unlock(&vma->vm_mm->page_table_lock);
5445 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5446 if (target_type == MC_TARGET_PAGE) {
5448 if (!isolate_lru_page(page)) {
5449 pc = lookup_page_cgroup(page);
5450 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
5451 pc, mc.from, mc.to)) {
5452 mc.precharge -= HPAGE_PMD_NR;
5453 mc.moved_charge += HPAGE_PMD_NR;
5455 putback_lru_page(page);
5459 spin_unlock(&vma->vm_mm->page_table_lock);
5463 if (pmd_trans_unstable(pmd))
5466 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5467 for (; addr != end; addr += PAGE_SIZE) {
5468 pte_t ptent = *(pte++);
5474 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5475 case MC_TARGET_PAGE:
5477 if (isolate_lru_page(page))
5479 pc = lookup_page_cgroup(page);
5480 if (!mem_cgroup_move_account(page, 1, pc,
5483 /* we uncharge from mc.from later. */
5486 putback_lru_page(page);
5487 put: /* get_mctgt_type() gets the page */
5490 case MC_TARGET_SWAP:
5492 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5494 /* we fixup refcnts and charges later. */
5502 pte_unmap_unlock(pte - 1, ptl);
5507 * We have consumed all precharges we got in can_attach().
5508 * We try charge one by one, but don't do any additional
5509 * charges to mc.to if we have failed in charge once in attach()
5512 ret = mem_cgroup_do_precharge(1);
5520 static void mem_cgroup_move_charge(struct mm_struct *mm)
5522 struct vm_area_struct *vma;
5524 lru_add_drain_all();
5526 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5528 * Someone who are holding the mmap_sem might be waiting in
5529 * waitq. So we cancel all extra charges, wake up all waiters,
5530 * and retry. Because we cancel precharges, we might not be able
5531 * to move enough charges, but moving charge is a best-effort
5532 * feature anyway, so it wouldn't be a big problem.
5534 __mem_cgroup_clear_mc();
5538 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5540 struct mm_walk mem_cgroup_move_charge_walk = {
5541 .pmd_entry = mem_cgroup_move_charge_pte_range,
5545 if (is_vm_hugetlb_page(vma))
5547 ret = walk_page_range(vma->vm_start, vma->vm_end,
5548 &mem_cgroup_move_charge_walk);
5551 * means we have consumed all precharges and failed in
5552 * doing additional charge. Just abandon here.
5556 up_read(&mm->mmap_sem);
5559 static void mem_cgroup_move_task(struct cgroup *cont,
5560 struct cgroup_taskset *tset)
5562 struct task_struct *p = cgroup_taskset_first(tset);
5563 struct mm_struct *mm = get_task_mm(p);
5567 mem_cgroup_move_charge(mm);
5571 mem_cgroup_clear_mc();
5573 #else /* !CONFIG_MMU */
5574 static int mem_cgroup_can_attach(struct cgroup *cgroup,
5575 struct cgroup_taskset *tset)
5579 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
5580 struct cgroup_taskset *tset)
5583 static void mem_cgroup_move_task(struct cgroup *cont,
5584 struct cgroup_taskset *tset)
5589 struct cgroup_subsys mem_cgroup_subsys = {
5591 .subsys_id = mem_cgroup_subsys_id,
5592 .create = mem_cgroup_create,
5593 .pre_destroy = mem_cgroup_pre_destroy,
5594 .destroy = mem_cgroup_destroy,
5595 .can_attach = mem_cgroup_can_attach,
5596 .cancel_attach = mem_cgroup_cancel_attach,
5597 .attach = mem_cgroup_move_task,
5598 .base_cftypes = mem_cgroup_files,
5601 .__DEPRECATED_clear_css_refs = true,
5604 #ifdef CONFIG_MEMCG_SWAP
5605 static int __init enable_swap_account(char *s)
5607 /* consider enabled if no parameter or 1 is given */
5608 if (!strcmp(s, "1"))
5609 really_do_swap_account = 1;
5610 else if (!strcmp(s, "0"))
5611 really_do_swap_account = 0;
5614 __setup("swapaccount=", enable_swap_account);