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_CGROUP_MEM_RES_CTLR_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_CGROUP_MEM_RES_CTLR_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_SWAPOUT, /* # 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_MAPPED,
382 MEM_CGROUP_CHARGE_TYPE_SHMEM, /* used by page migration of shmem */
383 MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
384 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
385 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
389 /* for encoding cft->private value on file */
392 #define _OOM_TYPE (2)
393 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
394 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
395 #define MEMFILE_ATTR(val) ((val) & 0xffff)
396 /* Used for OOM nofiier */
397 #define OOM_CONTROL (0)
400 * Reclaim flags for mem_cgroup_hierarchical_reclaim
402 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
403 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
404 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
405 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
407 static void mem_cgroup_get(struct mem_cgroup *memcg);
408 static void mem_cgroup_put(struct mem_cgroup *memcg);
410 /* Writing them here to avoid exposing memcg's inner layout */
411 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
412 #include <net/sock.h>
415 static bool mem_cgroup_is_root(struct mem_cgroup *memcg);
416 void sock_update_memcg(struct sock *sk)
418 if (mem_cgroup_sockets_enabled) {
419 struct mem_cgroup *memcg;
420 struct cg_proto *cg_proto;
422 BUG_ON(!sk->sk_prot->proto_cgroup);
424 /* Socket cloning can throw us here with sk_cgrp already
425 * filled. It won't however, necessarily happen from
426 * process context. So the test for root memcg given
427 * the current task's memcg won't help us in this case.
429 * Respecting the original socket's memcg is a better
430 * decision in this case.
433 BUG_ON(mem_cgroup_is_root(sk->sk_cgrp->memcg));
434 mem_cgroup_get(sk->sk_cgrp->memcg);
439 memcg = mem_cgroup_from_task(current);
440 cg_proto = sk->sk_prot->proto_cgroup(memcg);
441 if (!mem_cgroup_is_root(memcg) && memcg_proto_active(cg_proto)) {
442 mem_cgroup_get(memcg);
443 sk->sk_cgrp = cg_proto;
448 EXPORT_SYMBOL(sock_update_memcg);
450 void sock_release_memcg(struct sock *sk)
452 if (mem_cgroup_sockets_enabled && sk->sk_cgrp) {
453 struct mem_cgroup *memcg;
454 WARN_ON(!sk->sk_cgrp->memcg);
455 memcg = sk->sk_cgrp->memcg;
456 mem_cgroup_put(memcg);
461 struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
463 if (!memcg || mem_cgroup_is_root(memcg))
466 return &memcg->tcp_mem.cg_proto;
468 EXPORT_SYMBOL(tcp_proto_cgroup);
469 #endif /* CONFIG_INET */
470 #endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
472 #if defined(CONFIG_INET) && defined(CONFIG_CGROUP_MEM_RES_CTLR_KMEM)
473 static void disarm_sock_keys(struct mem_cgroup *memcg)
475 if (!memcg_proto_activated(&memcg->tcp_mem.cg_proto))
477 static_key_slow_dec(&memcg_socket_limit_enabled);
480 static void disarm_sock_keys(struct mem_cgroup *memcg)
485 static void drain_all_stock_async(struct mem_cgroup *memcg);
487 static struct mem_cgroup_per_zone *
488 mem_cgroup_zoneinfo(struct mem_cgroup *memcg, int nid, int zid)
490 return &memcg->info.nodeinfo[nid]->zoneinfo[zid];
493 struct cgroup_subsys_state *mem_cgroup_css(struct mem_cgroup *memcg)
498 static struct mem_cgroup_per_zone *
499 page_cgroup_zoneinfo(struct mem_cgroup *memcg, struct page *page)
501 int nid = page_to_nid(page);
502 int zid = page_zonenum(page);
504 return mem_cgroup_zoneinfo(memcg, nid, zid);
507 static struct mem_cgroup_tree_per_zone *
508 soft_limit_tree_node_zone(int nid, int zid)
510 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
513 static struct mem_cgroup_tree_per_zone *
514 soft_limit_tree_from_page(struct page *page)
516 int nid = page_to_nid(page);
517 int zid = page_zonenum(page);
519 return &soft_limit_tree.rb_tree_per_node[nid]->rb_tree_per_zone[zid];
523 __mem_cgroup_insert_exceeded(struct mem_cgroup *memcg,
524 struct mem_cgroup_per_zone *mz,
525 struct mem_cgroup_tree_per_zone *mctz,
526 unsigned long long new_usage_in_excess)
528 struct rb_node **p = &mctz->rb_root.rb_node;
529 struct rb_node *parent = NULL;
530 struct mem_cgroup_per_zone *mz_node;
535 mz->usage_in_excess = new_usage_in_excess;
536 if (!mz->usage_in_excess)
540 mz_node = rb_entry(parent, struct mem_cgroup_per_zone,
542 if (mz->usage_in_excess < mz_node->usage_in_excess)
545 * We can't avoid mem cgroups that are over their soft
546 * limit by the same amount
548 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
551 rb_link_node(&mz->tree_node, parent, p);
552 rb_insert_color(&mz->tree_node, &mctz->rb_root);
557 __mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
558 struct mem_cgroup_per_zone *mz,
559 struct mem_cgroup_tree_per_zone *mctz)
563 rb_erase(&mz->tree_node, &mctz->rb_root);
568 mem_cgroup_remove_exceeded(struct mem_cgroup *memcg,
569 struct mem_cgroup_per_zone *mz,
570 struct mem_cgroup_tree_per_zone *mctz)
572 spin_lock(&mctz->lock);
573 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
574 spin_unlock(&mctz->lock);
578 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
580 unsigned long long excess;
581 struct mem_cgroup_per_zone *mz;
582 struct mem_cgroup_tree_per_zone *mctz;
583 int nid = page_to_nid(page);
584 int zid = page_zonenum(page);
585 mctz = soft_limit_tree_from_page(page);
588 * Necessary to update all ancestors when hierarchy is used.
589 * because their event counter is not touched.
591 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
592 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
593 excess = res_counter_soft_limit_excess(&memcg->res);
595 * We have to update the tree if mz is on RB-tree or
596 * mem is over its softlimit.
598 if (excess || mz->on_tree) {
599 spin_lock(&mctz->lock);
600 /* if on-tree, remove it */
602 __mem_cgroup_remove_exceeded(memcg, mz, mctz);
604 * Insert again. mz->usage_in_excess will be updated.
605 * If excess is 0, no tree ops.
607 __mem_cgroup_insert_exceeded(memcg, mz, mctz, excess);
608 spin_unlock(&mctz->lock);
613 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
616 struct mem_cgroup_per_zone *mz;
617 struct mem_cgroup_tree_per_zone *mctz;
619 for_each_node(node) {
620 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
621 mz = mem_cgroup_zoneinfo(memcg, node, zone);
622 mctz = soft_limit_tree_node_zone(node, zone);
623 mem_cgroup_remove_exceeded(memcg, mz, mctz);
628 static struct mem_cgroup_per_zone *
629 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
631 struct rb_node *rightmost = NULL;
632 struct mem_cgroup_per_zone *mz;
636 rightmost = rb_last(&mctz->rb_root);
638 goto done; /* Nothing to reclaim from */
640 mz = rb_entry(rightmost, struct mem_cgroup_per_zone, tree_node);
642 * Remove the node now but someone else can add it back,
643 * we will to add it back at the end of reclaim to its correct
644 * position in the tree.
646 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
647 if (!res_counter_soft_limit_excess(&mz->memcg->res) ||
648 !css_tryget(&mz->memcg->css))
654 static struct mem_cgroup_per_zone *
655 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone *mctz)
657 struct mem_cgroup_per_zone *mz;
659 spin_lock(&mctz->lock);
660 mz = __mem_cgroup_largest_soft_limit_node(mctz);
661 spin_unlock(&mctz->lock);
666 * Implementation Note: reading percpu statistics for memcg.
668 * Both of vmstat[] and percpu_counter has threshold and do periodic
669 * synchronization to implement "quick" read. There are trade-off between
670 * reading cost and precision of value. Then, we may have a chance to implement
671 * a periodic synchronizion of counter in memcg's counter.
673 * But this _read() function is used for user interface now. The user accounts
674 * memory usage by memory cgroup and he _always_ requires exact value because
675 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
676 * have to visit all online cpus and make sum. So, for now, unnecessary
677 * synchronization is not implemented. (just implemented for cpu hotplug)
679 * If there are kernel internal actions which can make use of some not-exact
680 * value, and reading all cpu value can be performance bottleneck in some
681 * common workload, threashold and synchonization as vmstat[] should be
684 static long mem_cgroup_read_stat(struct mem_cgroup *memcg,
685 enum mem_cgroup_stat_index idx)
691 for_each_online_cpu(cpu)
692 val += per_cpu(memcg->stat->count[idx], cpu);
693 #ifdef CONFIG_HOTPLUG_CPU
694 spin_lock(&memcg->pcp_counter_lock);
695 val += memcg->nocpu_base.count[idx];
696 spin_unlock(&memcg->pcp_counter_lock);
702 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
705 int val = (charge) ? 1 : -1;
706 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAPOUT], val);
709 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
710 enum mem_cgroup_events_index idx)
712 unsigned long val = 0;
715 for_each_online_cpu(cpu)
716 val += per_cpu(memcg->stat->events[idx], cpu);
717 #ifdef CONFIG_HOTPLUG_CPU
718 spin_lock(&memcg->pcp_counter_lock);
719 val += memcg->nocpu_base.events[idx];
720 spin_unlock(&memcg->pcp_counter_lock);
725 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
726 bool anon, int nr_pages)
731 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
732 * counted as CACHE even if it's on ANON LRU.
735 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
738 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
741 /* pagein of a big page is an event. So, ignore page size */
743 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
745 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
746 nr_pages = -nr_pages; /* for event */
749 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
755 mem_cgroup_get_lru_size(struct lruvec *lruvec, enum lru_list lru)
757 struct mem_cgroup_per_zone *mz;
759 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
760 return mz->lru_size[lru];
764 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup *memcg, int nid, int zid,
765 unsigned int lru_mask)
767 struct mem_cgroup_per_zone *mz;
769 unsigned long ret = 0;
771 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
774 if (BIT(lru) & lru_mask)
775 ret += mz->lru_size[lru];
781 mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
782 int nid, unsigned int lru_mask)
787 for (zid = 0; zid < MAX_NR_ZONES; zid++)
788 total += mem_cgroup_zone_nr_lru_pages(memcg,
794 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
795 unsigned int lru_mask)
800 for_each_node_state(nid, N_HIGH_MEMORY)
801 total += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
805 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
806 enum mem_cgroup_events_target target)
808 unsigned long val, next;
810 val = __this_cpu_read(memcg->stat->nr_page_events);
811 next = __this_cpu_read(memcg->stat->targets[target]);
812 /* from time_after() in jiffies.h */
813 if ((long)next - (long)val < 0) {
815 case MEM_CGROUP_TARGET_THRESH:
816 next = val + THRESHOLDS_EVENTS_TARGET;
818 case MEM_CGROUP_TARGET_SOFTLIMIT:
819 next = val + SOFTLIMIT_EVENTS_TARGET;
821 case MEM_CGROUP_TARGET_NUMAINFO:
822 next = val + NUMAINFO_EVENTS_TARGET;
827 __this_cpu_write(memcg->stat->targets[target], next);
834 * Check events in order.
837 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
840 /* threshold event is triggered in finer grain than soft limit */
841 if (unlikely(mem_cgroup_event_ratelimit(memcg,
842 MEM_CGROUP_TARGET_THRESH))) {
844 bool do_numainfo __maybe_unused;
846 do_softlimit = mem_cgroup_event_ratelimit(memcg,
847 MEM_CGROUP_TARGET_SOFTLIMIT);
849 do_numainfo = mem_cgroup_event_ratelimit(memcg,
850 MEM_CGROUP_TARGET_NUMAINFO);
854 mem_cgroup_threshold(memcg);
855 if (unlikely(do_softlimit))
856 mem_cgroup_update_tree(memcg, page);
858 if (unlikely(do_numainfo))
859 atomic_inc(&memcg->numainfo_events);
865 struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
867 return container_of(cgroup_subsys_state(cont,
868 mem_cgroup_subsys_id), struct mem_cgroup,
872 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
875 * mm_update_next_owner() may clear mm->owner to NULL
876 * if it races with swapoff, page migration, etc.
877 * So this can be called with p == NULL.
882 return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
883 struct mem_cgroup, css);
886 struct mem_cgroup *try_get_mem_cgroup_from_mm(struct mm_struct *mm)
888 struct mem_cgroup *memcg = NULL;
893 * Because we have no locks, mm->owner's may be being moved to other
894 * cgroup. We use css_tryget() here even if this looks
895 * pessimistic (rather than adding locks here).
899 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
900 if (unlikely(!memcg))
902 } while (!css_tryget(&memcg->css));
908 * mem_cgroup_iter - iterate over memory cgroup hierarchy
909 * @root: hierarchy root
910 * @prev: previously returned memcg, NULL on first invocation
911 * @reclaim: cookie for shared reclaim walks, NULL for full walks
913 * Returns references to children of the hierarchy below @root, or
914 * @root itself, or %NULL after a full round-trip.
916 * Caller must pass the return value in @prev on subsequent
917 * invocations for reference counting, or use mem_cgroup_iter_break()
918 * to cancel a hierarchy walk before the round-trip is complete.
920 * Reclaimers can specify a zone and a priority level in @reclaim to
921 * divide up the memcgs in the hierarchy among all concurrent
922 * reclaimers operating on the same zone and priority.
924 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
925 struct mem_cgroup *prev,
926 struct mem_cgroup_reclaim_cookie *reclaim)
928 struct mem_cgroup *memcg = NULL;
931 if (mem_cgroup_disabled())
935 root = root_mem_cgroup;
937 if (prev && !reclaim)
938 id = css_id(&prev->css);
940 if (prev && prev != root)
943 if (!root->use_hierarchy && root != root_mem_cgroup) {
950 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
951 struct cgroup_subsys_state *css;
954 int nid = zone_to_nid(reclaim->zone);
955 int zid = zone_idx(reclaim->zone);
956 struct mem_cgroup_per_zone *mz;
958 mz = mem_cgroup_zoneinfo(root, nid, zid);
959 iter = &mz->reclaim_iter[reclaim->priority];
960 if (prev && reclaim->generation != iter->generation)
966 css = css_get_next(&mem_cgroup_subsys, id + 1, &root->css, &id);
968 if (css == &root->css || css_tryget(css))
969 memcg = container_of(css,
970 struct mem_cgroup, css);
979 else if (!prev && memcg)
980 reclaim->generation = iter->generation;
990 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
991 * @root: hierarchy root
992 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
994 void mem_cgroup_iter_break(struct mem_cgroup *root,
995 struct mem_cgroup *prev)
998 root = root_mem_cgroup;
999 if (prev && prev != root)
1000 css_put(&prev->css);
1004 * Iteration constructs for visiting all cgroups (under a tree). If
1005 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1006 * be used for reference counting.
1008 #define for_each_mem_cgroup_tree(iter, root) \
1009 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1011 iter = mem_cgroup_iter(root, iter, NULL))
1013 #define for_each_mem_cgroup(iter) \
1014 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1016 iter = mem_cgroup_iter(NULL, iter, NULL))
1018 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
1020 return (memcg == root_mem_cgroup);
1023 void mem_cgroup_count_vm_event(struct mm_struct *mm, enum vm_event_item idx)
1025 struct mem_cgroup *memcg;
1031 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
1032 if (unlikely(!memcg))
1037 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
1040 this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
1048 EXPORT_SYMBOL(mem_cgroup_count_vm_event);
1051 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1052 * @zone: zone of the wanted lruvec
1053 * @memcg: memcg of the wanted lruvec
1055 * Returns the lru list vector holding pages for the given @zone and
1056 * @mem. This can be the global zone lruvec, if the memory controller
1059 struct lruvec *mem_cgroup_zone_lruvec(struct zone *zone,
1060 struct mem_cgroup *memcg)
1062 struct mem_cgroup_per_zone *mz;
1064 if (mem_cgroup_disabled())
1065 return &zone->lruvec;
1067 mz = mem_cgroup_zoneinfo(memcg, zone_to_nid(zone), zone_idx(zone));
1072 * Following LRU functions are allowed to be used without PCG_LOCK.
1073 * Operations are called by routine of global LRU independently from memcg.
1074 * What we have to take care of here is validness of pc->mem_cgroup.
1076 * Changes to pc->mem_cgroup happens when
1079 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1080 * It is added to LRU before charge.
1081 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1082 * When moving account, the page is not on LRU. It's isolated.
1086 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1088 * @zone: zone of the page
1090 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct zone *zone)
1092 struct mem_cgroup_per_zone *mz;
1093 struct mem_cgroup *memcg;
1094 struct page_cgroup *pc;
1096 if (mem_cgroup_disabled())
1097 return &zone->lruvec;
1099 pc = lookup_page_cgroup(page);
1100 memcg = pc->mem_cgroup;
1103 * Surreptitiously switch any uncharged offlist page to root:
1104 * an uncharged page off lru does nothing to secure
1105 * its former mem_cgroup from sudden removal.
1107 * Our caller holds lru_lock, and PageCgroupUsed is updated
1108 * under page_cgroup lock: between them, they make all uses
1109 * of pc->mem_cgroup safe.
1111 if (!PageLRU(page) && !PageCgroupUsed(pc) && memcg != root_mem_cgroup)
1112 pc->mem_cgroup = memcg = root_mem_cgroup;
1114 mz = page_cgroup_zoneinfo(memcg, page);
1119 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1120 * @lruvec: mem_cgroup per zone lru vector
1121 * @lru: index of lru list the page is sitting on
1122 * @nr_pages: positive when adding or negative when removing
1124 * This function must be called when a page is added to or removed from an
1127 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1130 struct mem_cgroup_per_zone *mz;
1131 unsigned long *lru_size;
1133 if (mem_cgroup_disabled())
1136 mz = container_of(lruvec, struct mem_cgroup_per_zone, lruvec);
1137 lru_size = mz->lru_size + lru;
1138 *lru_size += nr_pages;
1139 VM_BUG_ON((long)(*lru_size) < 0);
1143 * Checks whether given mem is same or in the root_mem_cgroup's
1146 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1147 struct mem_cgroup *memcg)
1149 if (root_memcg == memcg)
1151 if (!root_memcg->use_hierarchy || !memcg)
1153 return css_is_ancestor(&memcg->css, &root_memcg->css);
1156 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup *root_memcg,
1157 struct mem_cgroup *memcg)
1162 ret = __mem_cgroup_same_or_subtree(root_memcg, memcg);
1167 int task_in_mem_cgroup(struct task_struct *task, const struct mem_cgroup *memcg)
1170 struct mem_cgroup *curr = NULL;
1171 struct task_struct *p;
1173 p = find_lock_task_mm(task);
1175 curr = try_get_mem_cgroup_from_mm(p->mm);
1179 * All threads may have already detached their mm's, but the oom
1180 * killer still needs to detect if they have already been oom
1181 * killed to prevent needlessly killing additional tasks.
1184 curr = mem_cgroup_from_task(task);
1186 css_get(&curr->css);
1192 * We should check use_hierarchy of "memcg" not "curr". Because checking
1193 * use_hierarchy of "curr" here make this function true if hierarchy is
1194 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1195 * hierarchy(even if use_hierarchy is disabled in "memcg").
1197 ret = mem_cgroup_same_or_subtree(memcg, curr);
1198 css_put(&curr->css);
1202 int mem_cgroup_inactive_anon_is_low(struct lruvec *lruvec)
1204 unsigned long inactive_ratio;
1205 unsigned long inactive;
1206 unsigned long active;
1209 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_ANON);
1210 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_ANON);
1212 gb = (inactive + active) >> (30 - PAGE_SHIFT);
1214 inactive_ratio = int_sqrt(10 * gb);
1218 return inactive * inactive_ratio < active;
1221 int mem_cgroup_inactive_file_is_low(struct lruvec *lruvec)
1223 unsigned long active;
1224 unsigned long inactive;
1226 inactive = mem_cgroup_get_lru_size(lruvec, LRU_INACTIVE_FILE);
1227 active = mem_cgroup_get_lru_size(lruvec, LRU_ACTIVE_FILE);
1229 return (active > inactive);
1232 #define mem_cgroup_from_res_counter(counter, member) \
1233 container_of(counter, struct mem_cgroup, member)
1236 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1237 * @mem: the memory cgroup
1239 * Returns the maximum amount of memory @mem can be charged with, in
1242 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1244 unsigned long long margin;
1246 margin = res_counter_margin(&memcg->res);
1247 if (do_swap_account)
1248 margin = min(margin, res_counter_margin(&memcg->memsw));
1249 return margin >> PAGE_SHIFT;
1252 int mem_cgroup_swappiness(struct mem_cgroup *memcg)
1254 struct cgroup *cgrp = memcg->css.cgroup;
1257 if (cgrp->parent == NULL)
1258 return vm_swappiness;
1260 return memcg->swappiness;
1264 * memcg->moving_account is used for checking possibility that some thread is
1265 * calling move_account(). When a thread on CPU-A starts moving pages under
1266 * a memcg, other threads should check memcg->moving_account under
1267 * rcu_read_lock(), like this:
1271 * memcg->moving_account+1 if (memcg->mocing_account)
1273 * synchronize_rcu() update something.
1278 /* for quick checking without looking up memcg */
1279 atomic_t memcg_moving __read_mostly;
1281 static void mem_cgroup_start_move(struct mem_cgroup *memcg)
1283 atomic_inc(&memcg_moving);
1284 atomic_inc(&memcg->moving_account);
1288 static void mem_cgroup_end_move(struct mem_cgroup *memcg)
1291 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1292 * We check NULL in callee rather than caller.
1295 atomic_dec(&memcg_moving);
1296 atomic_dec(&memcg->moving_account);
1301 * 2 routines for checking "mem" is under move_account() or not.
1303 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1304 * is used for avoiding races in accounting. If true,
1305 * pc->mem_cgroup may be overwritten.
1307 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1308 * under hierarchy of moving cgroups. This is for
1309 * waiting at hith-memory prressure caused by "move".
1312 static bool mem_cgroup_stolen(struct mem_cgroup *memcg)
1314 VM_BUG_ON(!rcu_read_lock_held());
1315 return atomic_read(&memcg->moving_account) > 0;
1318 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1320 struct mem_cgroup *from;
1321 struct mem_cgroup *to;
1324 * Unlike task_move routines, we access mc.to, mc.from not under
1325 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1327 spin_lock(&mc.lock);
1333 ret = mem_cgroup_same_or_subtree(memcg, from)
1334 || mem_cgroup_same_or_subtree(memcg, to);
1336 spin_unlock(&mc.lock);
1340 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1342 if (mc.moving_task && current != mc.moving_task) {
1343 if (mem_cgroup_under_move(memcg)) {
1345 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1346 /* moving charge context might have finished. */
1349 finish_wait(&mc.waitq, &wait);
1357 * Take this lock when
1358 * - a code tries to modify page's memcg while it's USED.
1359 * - a code tries to modify page state accounting in a memcg.
1360 * see mem_cgroup_stolen(), too.
1362 static void move_lock_mem_cgroup(struct mem_cgroup *memcg,
1363 unsigned long *flags)
1365 spin_lock_irqsave(&memcg->move_lock, *flags);
1368 static void move_unlock_mem_cgroup(struct mem_cgroup *memcg,
1369 unsigned long *flags)
1371 spin_unlock_irqrestore(&memcg->move_lock, *flags);
1375 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1376 * @memcg: The memory cgroup that went over limit
1377 * @p: Task that is going to be killed
1379 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1382 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1384 struct cgroup *task_cgrp;
1385 struct cgroup *mem_cgrp;
1387 * Need a buffer in BSS, can't rely on allocations. The code relies
1388 * on the assumption that OOM is serialized for memory controller.
1389 * If this assumption is broken, revisit this code.
1391 static char memcg_name[PATH_MAX];
1399 mem_cgrp = memcg->css.cgroup;
1400 task_cgrp = task_cgroup(p, mem_cgroup_subsys_id);
1402 ret = cgroup_path(task_cgrp, memcg_name, PATH_MAX);
1405 * Unfortunately, we are unable to convert to a useful name
1406 * But we'll still print out the usage information
1413 printk(KERN_INFO "Task in %s killed", memcg_name);
1416 ret = cgroup_path(mem_cgrp, memcg_name, PATH_MAX);
1424 * Continues from above, so we don't need an KERN_ level
1426 printk(KERN_CONT " as a result of limit of %s\n", memcg_name);
1429 printk(KERN_INFO "memory: usage %llukB, limit %llukB, failcnt %llu\n",
1430 res_counter_read_u64(&memcg->res, RES_USAGE) >> 10,
1431 res_counter_read_u64(&memcg->res, RES_LIMIT) >> 10,
1432 res_counter_read_u64(&memcg->res, RES_FAILCNT));
1433 printk(KERN_INFO "memory+swap: usage %llukB, limit %llukB, "
1435 res_counter_read_u64(&memcg->memsw, RES_USAGE) >> 10,
1436 res_counter_read_u64(&memcg->memsw, RES_LIMIT) >> 10,
1437 res_counter_read_u64(&memcg->memsw, RES_FAILCNT));
1441 * This function returns the number of memcg under hierarchy tree. Returns
1442 * 1(self count) if no children.
1444 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1447 struct mem_cgroup *iter;
1449 for_each_mem_cgroup_tree(iter, memcg)
1455 * Return the memory (and swap, if configured) limit for a memcg.
1457 u64 mem_cgroup_get_limit(struct mem_cgroup *memcg)
1462 limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
1463 limit += total_swap_pages << PAGE_SHIFT;
1465 memsw = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
1467 * If memsw is finite and limits the amount of swap space available
1468 * to this memcg, return that limit.
1470 return min(limit, memsw);
1473 static unsigned long mem_cgroup_reclaim(struct mem_cgroup *memcg,
1475 unsigned long flags)
1477 unsigned long total = 0;
1478 bool noswap = false;
1481 if (flags & MEM_CGROUP_RECLAIM_NOSWAP)
1483 if (!(flags & MEM_CGROUP_RECLAIM_SHRINK) && memcg->memsw_is_minimum)
1486 for (loop = 0; loop < MEM_CGROUP_MAX_RECLAIM_LOOPS; loop++) {
1488 drain_all_stock_async(memcg);
1489 total += try_to_free_mem_cgroup_pages(memcg, gfp_mask, noswap);
1491 * Allow limit shrinkers, which are triggered directly
1492 * by userspace, to catch signals and stop reclaim
1493 * after minimal progress, regardless of the margin.
1495 if (total && (flags & MEM_CGROUP_RECLAIM_SHRINK))
1497 if (mem_cgroup_margin(memcg))
1500 * If nothing was reclaimed after two attempts, there
1501 * may be no reclaimable pages in this hierarchy.
1510 * test_mem_cgroup_node_reclaimable
1511 * @mem: the target memcg
1512 * @nid: the node ID to be checked.
1513 * @noswap : specify true here if the user wants flle only information.
1515 * This function returns whether the specified memcg contains any
1516 * reclaimable pages on a node. Returns true if there are any reclaimable
1517 * pages in the node.
1519 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1520 int nid, bool noswap)
1522 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1524 if (noswap || !total_swap_pages)
1526 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1531 #if MAX_NUMNODES > 1
1534 * Always updating the nodemask is not very good - even if we have an empty
1535 * list or the wrong list here, we can start from some node and traverse all
1536 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1539 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1543 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1544 * pagein/pageout changes since the last update.
1546 if (!atomic_read(&memcg->numainfo_events))
1548 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1551 /* make a nodemask where this memcg uses memory from */
1552 memcg->scan_nodes = node_states[N_HIGH_MEMORY];
1554 for_each_node_mask(nid, node_states[N_HIGH_MEMORY]) {
1556 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1557 node_clear(nid, memcg->scan_nodes);
1560 atomic_set(&memcg->numainfo_events, 0);
1561 atomic_set(&memcg->numainfo_updating, 0);
1565 * Selecting a node where we start reclaim from. Because what we need is just
1566 * reducing usage counter, start from anywhere is O,K. Considering
1567 * memory reclaim from current node, there are pros. and cons.
1569 * Freeing memory from current node means freeing memory from a node which
1570 * we'll use or we've used. So, it may make LRU bad. And if several threads
1571 * hit limits, it will see a contention on a node. But freeing from remote
1572 * node means more costs for memory reclaim because of memory latency.
1574 * Now, we use round-robin. Better algorithm is welcomed.
1576 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1580 mem_cgroup_may_update_nodemask(memcg);
1581 node = memcg->last_scanned_node;
1583 node = next_node(node, memcg->scan_nodes);
1584 if (node == MAX_NUMNODES)
1585 node = first_node(memcg->scan_nodes);
1587 * We call this when we hit limit, not when pages are added to LRU.
1588 * No LRU may hold pages because all pages are UNEVICTABLE or
1589 * memcg is too small and all pages are not on LRU. In that case,
1590 * we use curret node.
1592 if (unlikely(node == MAX_NUMNODES))
1593 node = numa_node_id();
1595 memcg->last_scanned_node = node;
1600 * Check all nodes whether it contains reclaimable pages or not.
1601 * For quick scan, we make use of scan_nodes. This will allow us to skip
1602 * unused nodes. But scan_nodes is lazily updated and may not cotain
1603 * enough new information. We need to do double check.
1605 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1610 * quick check...making use of scan_node.
1611 * We can skip unused nodes.
1613 if (!nodes_empty(memcg->scan_nodes)) {
1614 for (nid = first_node(memcg->scan_nodes);
1616 nid = next_node(nid, memcg->scan_nodes)) {
1618 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1623 * Check rest of nodes.
1625 for_each_node_state(nid, N_HIGH_MEMORY) {
1626 if (node_isset(nid, memcg->scan_nodes))
1628 if (test_mem_cgroup_node_reclaimable(memcg, nid, noswap))
1635 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1640 static bool mem_cgroup_reclaimable(struct mem_cgroup *memcg, bool noswap)
1642 return test_mem_cgroup_node_reclaimable(memcg, 0, noswap);
1646 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1649 unsigned long *total_scanned)
1651 struct mem_cgroup *victim = NULL;
1654 unsigned long excess;
1655 unsigned long nr_scanned;
1656 struct mem_cgroup_reclaim_cookie reclaim = {
1661 excess = res_counter_soft_limit_excess(&root_memcg->res) >> PAGE_SHIFT;
1664 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1669 * If we have not been able to reclaim
1670 * anything, it might because there are
1671 * no reclaimable pages under this hierarchy
1676 * We want to do more targeted reclaim.
1677 * excess >> 2 is not to excessive so as to
1678 * reclaim too much, nor too less that we keep
1679 * coming back to reclaim from this cgroup
1681 if (total >= (excess >> 2) ||
1682 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1687 if (!mem_cgroup_reclaimable(victim, false))
1689 total += mem_cgroup_shrink_node_zone(victim, gfp_mask, false,
1691 *total_scanned += nr_scanned;
1692 if (!res_counter_soft_limit_excess(&root_memcg->res))
1695 mem_cgroup_iter_break(root_memcg, victim);
1700 * Check OOM-Killer is already running under our hierarchy.
1701 * If someone is running, return false.
1702 * Has to be called with memcg_oom_lock
1704 static bool mem_cgroup_oom_lock(struct mem_cgroup *memcg)
1706 struct mem_cgroup *iter, *failed = NULL;
1708 for_each_mem_cgroup_tree(iter, memcg) {
1709 if (iter->oom_lock) {
1711 * this subtree of our hierarchy is already locked
1712 * so we cannot give a lock.
1715 mem_cgroup_iter_break(memcg, iter);
1718 iter->oom_lock = true;
1725 * OK, we failed to lock the whole subtree so we have to clean up
1726 * what we set up to the failing subtree
1728 for_each_mem_cgroup_tree(iter, memcg) {
1729 if (iter == failed) {
1730 mem_cgroup_iter_break(memcg, iter);
1733 iter->oom_lock = false;
1739 * Has to be called with memcg_oom_lock
1741 static int mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1743 struct mem_cgroup *iter;
1745 for_each_mem_cgroup_tree(iter, memcg)
1746 iter->oom_lock = false;
1750 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1752 struct mem_cgroup *iter;
1754 for_each_mem_cgroup_tree(iter, memcg)
1755 atomic_inc(&iter->under_oom);
1758 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1760 struct mem_cgroup *iter;
1763 * When a new child is created while the hierarchy is under oom,
1764 * mem_cgroup_oom_lock() may not be called. We have to use
1765 * atomic_add_unless() here.
1767 for_each_mem_cgroup_tree(iter, memcg)
1768 atomic_add_unless(&iter->under_oom, -1, 0);
1771 static DEFINE_SPINLOCK(memcg_oom_lock);
1772 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1774 struct oom_wait_info {
1775 struct mem_cgroup *memcg;
1779 static int memcg_oom_wake_function(wait_queue_t *wait,
1780 unsigned mode, int sync, void *arg)
1782 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1783 struct mem_cgroup *oom_wait_memcg;
1784 struct oom_wait_info *oom_wait_info;
1786 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1787 oom_wait_memcg = oom_wait_info->memcg;
1790 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
1791 * Then we can use css_is_ancestor without taking care of RCU.
1793 if (!mem_cgroup_same_or_subtree(oom_wait_memcg, wake_memcg)
1794 && !mem_cgroup_same_or_subtree(wake_memcg, oom_wait_memcg))
1796 return autoremove_wake_function(wait, mode, sync, arg);
1799 static void memcg_wakeup_oom(struct mem_cgroup *memcg)
1801 /* for filtering, pass "memcg" as argument. */
1802 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1805 static void memcg_oom_recover(struct mem_cgroup *memcg)
1807 if (memcg && atomic_read(&memcg->under_oom))
1808 memcg_wakeup_oom(memcg);
1812 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1814 static bool mem_cgroup_handle_oom(struct mem_cgroup *memcg, gfp_t mask,
1817 struct oom_wait_info owait;
1818 bool locked, need_to_kill;
1820 owait.memcg = memcg;
1821 owait.wait.flags = 0;
1822 owait.wait.func = memcg_oom_wake_function;
1823 owait.wait.private = current;
1824 INIT_LIST_HEAD(&owait.wait.task_list);
1825 need_to_kill = true;
1826 mem_cgroup_mark_under_oom(memcg);
1828 /* At first, try to OOM lock hierarchy under memcg.*/
1829 spin_lock(&memcg_oom_lock);
1830 locked = mem_cgroup_oom_lock(memcg);
1832 * Even if signal_pending(), we can't quit charge() loop without
1833 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1834 * under OOM is always welcomed, use TASK_KILLABLE here.
1836 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1837 if (!locked || memcg->oom_kill_disable)
1838 need_to_kill = false;
1840 mem_cgroup_oom_notify(memcg);
1841 spin_unlock(&memcg_oom_lock);
1844 finish_wait(&memcg_oom_waitq, &owait.wait);
1845 mem_cgroup_out_of_memory(memcg, mask, order);
1848 finish_wait(&memcg_oom_waitq, &owait.wait);
1850 spin_lock(&memcg_oom_lock);
1852 mem_cgroup_oom_unlock(memcg);
1853 memcg_wakeup_oom(memcg);
1854 spin_unlock(&memcg_oom_lock);
1856 mem_cgroup_unmark_under_oom(memcg);
1858 if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current))
1860 /* Give chance to dying process */
1861 schedule_timeout_uninterruptible(1);
1866 * Currently used to update mapped file statistics, but the routine can be
1867 * generalized to update other statistics as well.
1869 * Notes: Race condition
1871 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1872 * it tends to be costly. But considering some conditions, we doesn't need
1873 * to do so _always_.
1875 * Considering "charge", lock_page_cgroup() is not required because all
1876 * file-stat operations happen after a page is attached to radix-tree. There
1877 * are no race with "charge".
1879 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1880 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1881 * if there are race with "uncharge". Statistics itself is properly handled
1884 * Considering "move", this is an only case we see a race. To make the race
1885 * small, we check mm->moving_account and detect there are possibility of race
1886 * If there is, we take a lock.
1889 void __mem_cgroup_begin_update_page_stat(struct page *page,
1890 bool *locked, unsigned long *flags)
1892 struct mem_cgroup *memcg;
1893 struct page_cgroup *pc;
1895 pc = lookup_page_cgroup(page);
1897 memcg = pc->mem_cgroup;
1898 if (unlikely(!memcg || !PageCgroupUsed(pc)))
1901 * If this memory cgroup is not under account moving, we don't
1902 * need to take move_lock_page_cgroup(). Because we already hold
1903 * rcu_read_lock(), any calls to move_account will be delayed until
1904 * rcu_read_unlock() if mem_cgroup_stolen() == true.
1906 if (!mem_cgroup_stolen(memcg))
1909 move_lock_mem_cgroup(memcg, flags);
1910 if (memcg != pc->mem_cgroup || !PageCgroupUsed(pc)) {
1911 move_unlock_mem_cgroup(memcg, flags);
1917 void __mem_cgroup_end_update_page_stat(struct page *page, unsigned long *flags)
1919 struct page_cgroup *pc = lookup_page_cgroup(page);
1922 * It's guaranteed that pc->mem_cgroup never changes while
1923 * lock is held because a routine modifies pc->mem_cgroup
1924 * should take move_lock_page_cgroup().
1926 move_unlock_mem_cgroup(pc->mem_cgroup, flags);
1929 void mem_cgroup_update_page_stat(struct page *page,
1930 enum mem_cgroup_page_stat_item idx, int val)
1932 struct mem_cgroup *memcg;
1933 struct page_cgroup *pc = lookup_page_cgroup(page);
1934 unsigned long uninitialized_var(flags);
1936 if (mem_cgroup_disabled())
1939 memcg = pc->mem_cgroup;
1940 if (unlikely(!memcg || !PageCgroupUsed(pc)))
1944 case MEMCG_NR_FILE_MAPPED:
1945 idx = MEM_CGROUP_STAT_FILE_MAPPED;
1951 this_cpu_add(memcg->stat->count[idx], val);
1955 * size of first charge trial. "32" comes from vmscan.c's magic value.
1956 * TODO: maybe necessary to use big numbers in big irons.
1958 #define CHARGE_BATCH 32U
1959 struct memcg_stock_pcp {
1960 struct mem_cgroup *cached; /* this never be root cgroup */
1961 unsigned int nr_pages;
1962 struct work_struct work;
1963 unsigned long flags;
1964 #define FLUSHING_CACHED_CHARGE 0
1966 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1967 static DEFINE_MUTEX(percpu_charge_mutex);
1970 * Try to consume stocked charge on this cpu. If success, one page is consumed
1971 * from local stock and true is returned. If the stock is 0 or charges from a
1972 * cgroup which is not current target, returns false. This stock will be
1975 static bool consume_stock(struct mem_cgroup *memcg)
1977 struct memcg_stock_pcp *stock;
1980 stock = &get_cpu_var(memcg_stock);
1981 if (memcg == stock->cached && stock->nr_pages)
1983 else /* need to call res_counter_charge */
1985 put_cpu_var(memcg_stock);
1990 * Returns stocks cached in percpu to res_counter and reset cached information.
1992 static void drain_stock(struct memcg_stock_pcp *stock)
1994 struct mem_cgroup *old = stock->cached;
1996 if (stock->nr_pages) {
1997 unsigned long bytes = stock->nr_pages * PAGE_SIZE;
1999 res_counter_uncharge(&old->res, bytes);
2000 if (do_swap_account)
2001 res_counter_uncharge(&old->memsw, bytes);
2002 stock->nr_pages = 0;
2004 stock->cached = NULL;
2008 * This must be called under preempt disabled or must be called by
2009 * a thread which is pinned to local cpu.
2011 static void drain_local_stock(struct work_struct *dummy)
2013 struct memcg_stock_pcp *stock = &__get_cpu_var(memcg_stock);
2015 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2019 * Cache charges(val) which is from res_counter, to local per_cpu area.
2020 * This will be consumed by consume_stock() function, later.
2022 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2024 struct memcg_stock_pcp *stock = &get_cpu_var(memcg_stock);
2026 if (stock->cached != memcg) { /* reset if necessary */
2028 stock->cached = memcg;
2030 stock->nr_pages += nr_pages;
2031 put_cpu_var(memcg_stock);
2035 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2036 * of the hierarchy under it. sync flag says whether we should block
2037 * until the work is done.
2039 static void drain_all_stock(struct mem_cgroup *root_memcg, bool sync)
2043 /* Notify other cpus that system-wide "drain" is running */
2046 for_each_online_cpu(cpu) {
2047 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2048 struct mem_cgroup *memcg;
2050 memcg = stock->cached;
2051 if (!memcg || !stock->nr_pages)
2053 if (!mem_cgroup_same_or_subtree(root_memcg, memcg))
2055 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2057 drain_local_stock(&stock->work);
2059 schedule_work_on(cpu, &stock->work);
2067 for_each_online_cpu(cpu) {
2068 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2069 if (test_bit(FLUSHING_CACHED_CHARGE, &stock->flags))
2070 flush_work(&stock->work);
2077 * Tries to drain stocked charges in other cpus. This function is asynchronous
2078 * and just put a work per cpu for draining localy on each cpu. Caller can
2079 * expects some charges will be back to res_counter later but cannot wait for
2082 static void drain_all_stock_async(struct mem_cgroup *root_memcg)
2085 * If someone calls draining, avoid adding more kworker runs.
2087 if (!mutex_trylock(&percpu_charge_mutex))
2089 drain_all_stock(root_memcg, false);
2090 mutex_unlock(&percpu_charge_mutex);
2093 /* This is a synchronous drain interface. */
2094 static void drain_all_stock_sync(struct mem_cgroup *root_memcg)
2096 /* called when force_empty is called */
2097 mutex_lock(&percpu_charge_mutex);
2098 drain_all_stock(root_memcg, true);
2099 mutex_unlock(&percpu_charge_mutex);
2103 * This function drains percpu counter value from DEAD cpu and
2104 * move it to local cpu. Note that this function can be preempted.
2106 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup *memcg, int cpu)
2110 spin_lock(&memcg->pcp_counter_lock);
2111 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
2112 long x = per_cpu(memcg->stat->count[i], cpu);
2114 per_cpu(memcg->stat->count[i], cpu) = 0;
2115 memcg->nocpu_base.count[i] += x;
2117 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
2118 unsigned long x = per_cpu(memcg->stat->events[i], cpu);
2120 per_cpu(memcg->stat->events[i], cpu) = 0;
2121 memcg->nocpu_base.events[i] += x;
2123 spin_unlock(&memcg->pcp_counter_lock);
2126 static int __cpuinit memcg_cpu_hotplug_callback(struct notifier_block *nb,
2127 unsigned long action,
2130 int cpu = (unsigned long)hcpu;
2131 struct memcg_stock_pcp *stock;
2132 struct mem_cgroup *iter;
2134 if (action == CPU_ONLINE)
2137 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
2140 for_each_mem_cgroup(iter)
2141 mem_cgroup_drain_pcp_counter(iter, cpu);
2143 stock = &per_cpu(memcg_stock, cpu);
2149 /* See __mem_cgroup_try_charge() for details */
2151 CHARGE_OK, /* success */
2152 CHARGE_RETRY, /* need to retry but retry is not bad */
2153 CHARGE_NOMEM, /* we can't do more. return -ENOMEM */
2154 CHARGE_WOULDBLOCK, /* GFP_WAIT wasn't set and no enough res. */
2155 CHARGE_OOM_DIE, /* the current is killed because of OOM */
2158 static int mem_cgroup_do_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2159 unsigned int nr_pages, bool oom_check)
2161 unsigned long csize = nr_pages * PAGE_SIZE;
2162 struct mem_cgroup *mem_over_limit;
2163 struct res_counter *fail_res;
2164 unsigned long flags = 0;
2167 ret = res_counter_charge(&memcg->res, csize, &fail_res);
2170 if (!do_swap_account)
2172 ret = res_counter_charge(&memcg->memsw, csize, &fail_res);
2176 res_counter_uncharge(&memcg->res, csize);
2177 mem_over_limit = mem_cgroup_from_res_counter(fail_res, memsw);
2178 flags |= MEM_CGROUP_RECLAIM_NOSWAP;
2180 mem_over_limit = mem_cgroup_from_res_counter(fail_res, res);
2182 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
2183 * of regular pages (CHARGE_BATCH), or a single regular page (1).
2185 * Never reclaim on behalf of optional batching, retry with a
2186 * single page instead.
2188 if (nr_pages == CHARGE_BATCH)
2189 return CHARGE_RETRY;
2191 if (!(gfp_mask & __GFP_WAIT))
2192 return CHARGE_WOULDBLOCK;
2194 ret = mem_cgroup_reclaim(mem_over_limit, gfp_mask, flags);
2195 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2196 return CHARGE_RETRY;
2198 * Even though the limit is exceeded at this point, reclaim
2199 * may have been able to free some pages. Retry the charge
2200 * before killing the task.
2202 * Only for regular pages, though: huge pages are rather
2203 * unlikely to succeed so close to the limit, and we fall back
2204 * to regular pages anyway in case of failure.
2206 if (nr_pages == 1 && ret)
2207 return CHARGE_RETRY;
2210 * At task move, charge accounts can be doubly counted. So, it's
2211 * better to wait until the end of task_move if something is going on.
2213 if (mem_cgroup_wait_acct_move(mem_over_limit))
2214 return CHARGE_RETRY;
2216 /* If we don't need to call oom-killer at el, return immediately */
2218 return CHARGE_NOMEM;
2220 if (!mem_cgroup_handle_oom(mem_over_limit, gfp_mask, get_order(csize)))
2221 return CHARGE_OOM_DIE;
2223 return CHARGE_RETRY;
2227 * __mem_cgroup_try_charge() does
2228 * 1. detect memcg to be charged against from passed *mm and *ptr,
2229 * 2. update res_counter
2230 * 3. call memory reclaim if necessary.
2232 * In some special case, if the task is fatal, fatal_signal_pending() or
2233 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2234 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2235 * as possible without any hazards. 2: all pages should have a valid
2236 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2237 * pointer, that is treated as a charge to root_mem_cgroup.
2239 * So __mem_cgroup_try_charge() will return
2240 * 0 ... on success, filling *ptr with a valid memcg pointer.
2241 * -ENOMEM ... charge failure because of resource limits.
2242 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2244 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2245 * the oom-killer can be invoked.
2247 static int __mem_cgroup_try_charge(struct mm_struct *mm,
2249 unsigned int nr_pages,
2250 struct mem_cgroup **ptr,
2253 unsigned int batch = max(CHARGE_BATCH, nr_pages);
2254 int nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2255 struct mem_cgroup *memcg = NULL;
2259 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2260 * in system level. So, allow to go ahead dying process in addition to
2263 if (unlikely(test_thread_flag(TIF_MEMDIE)
2264 || fatal_signal_pending(current)))
2268 * We always charge the cgroup the mm_struct belongs to.
2269 * The mm_struct's mem_cgroup changes on task migration if the
2270 * thread group leader migrates. It's possible that mm is not
2271 * set, if so charge the init_mm (happens for pagecache usage).
2274 *ptr = root_mem_cgroup;
2276 if (*ptr) { /* css should be a valid one */
2278 VM_BUG_ON(css_is_removed(&memcg->css));
2279 if (mem_cgroup_is_root(memcg))
2281 if (nr_pages == 1 && consume_stock(memcg))
2283 css_get(&memcg->css);
2285 struct task_struct *p;
2288 p = rcu_dereference(mm->owner);
2290 * Because we don't have task_lock(), "p" can exit.
2291 * In that case, "memcg" can point to root or p can be NULL with
2292 * race with swapoff. Then, we have small risk of mis-accouning.
2293 * But such kind of mis-account by race always happens because
2294 * we don't have cgroup_mutex(). It's overkill and we allo that
2296 * (*) swapoff at el will charge against mm-struct not against
2297 * task-struct. So, mm->owner can be NULL.
2299 memcg = mem_cgroup_from_task(p);
2301 memcg = root_mem_cgroup;
2302 if (mem_cgroup_is_root(memcg)) {
2306 if (nr_pages == 1 && consume_stock(memcg)) {
2308 * It seems dagerous to access memcg without css_get().
2309 * But considering how consume_stok works, it's not
2310 * necessary. If consume_stock success, some charges
2311 * from this memcg are cached on this cpu. So, we
2312 * don't need to call css_get()/css_tryget() before
2313 * calling consume_stock().
2318 /* after here, we may be blocked. we need to get refcnt */
2319 if (!css_tryget(&memcg->css)) {
2329 /* If killed, bypass charge */
2330 if (fatal_signal_pending(current)) {
2331 css_put(&memcg->css);
2336 if (oom && !nr_oom_retries) {
2338 nr_oom_retries = MEM_CGROUP_RECLAIM_RETRIES;
2341 ret = mem_cgroup_do_charge(memcg, gfp_mask, batch, oom_check);
2345 case CHARGE_RETRY: /* not in OOM situation but retry */
2347 css_put(&memcg->css);
2350 case CHARGE_WOULDBLOCK: /* !__GFP_WAIT */
2351 css_put(&memcg->css);
2353 case CHARGE_NOMEM: /* OOM routine works */
2355 css_put(&memcg->css);
2358 /* If oom, we never return -ENOMEM */
2361 case CHARGE_OOM_DIE: /* Killed by OOM Killer */
2362 css_put(&memcg->css);
2365 } while (ret != CHARGE_OK);
2367 if (batch > nr_pages)
2368 refill_stock(memcg, batch - nr_pages);
2369 css_put(&memcg->css);
2377 *ptr = root_mem_cgroup;
2382 * Somemtimes we have to undo a charge we got by try_charge().
2383 * This function is for that and do uncharge, put css's refcnt.
2384 * gotten by try_charge().
2386 static void __mem_cgroup_cancel_charge(struct mem_cgroup *memcg,
2387 unsigned int nr_pages)
2389 if (!mem_cgroup_is_root(memcg)) {
2390 unsigned long bytes = nr_pages * PAGE_SIZE;
2392 res_counter_uncharge(&memcg->res, bytes);
2393 if (do_swap_account)
2394 res_counter_uncharge(&memcg->memsw, bytes);
2399 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2400 * This is useful when moving usage to parent cgroup.
2402 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup *memcg,
2403 unsigned int nr_pages)
2405 unsigned long bytes = nr_pages * PAGE_SIZE;
2407 if (mem_cgroup_is_root(memcg))
2410 res_counter_uncharge_until(&memcg->res, memcg->res.parent, bytes);
2411 if (do_swap_account)
2412 res_counter_uncharge_until(&memcg->memsw,
2413 memcg->memsw.parent, bytes);
2417 * A helper function to get mem_cgroup from ID. must be called under
2418 * rcu_read_lock(). The caller must check css_is_removed() or some if
2419 * it's concern. (dropping refcnt from swap can be called against removed
2422 static struct mem_cgroup *mem_cgroup_lookup(unsigned short id)
2424 struct cgroup_subsys_state *css;
2426 /* ID 0 is unused ID */
2429 css = css_lookup(&mem_cgroup_subsys, id);
2432 return container_of(css, struct mem_cgroup, css);
2435 struct mem_cgroup *try_get_mem_cgroup_from_page(struct page *page)
2437 struct mem_cgroup *memcg = NULL;
2438 struct page_cgroup *pc;
2442 VM_BUG_ON(!PageLocked(page));
2444 pc = lookup_page_cgroup(page);
2445 lock_page_cgroup(pc);
2446 if (PageCgroupUsed(pc)) {
2447 memcg = pc->mem_cgroup;
2448 if (memcg && !css_tryget(&memcg->css))
2450 } else if (PageSwapCache(page)) {
2451 ent.val = page_private(page);
2452 id = lookup_swap_cgroup_id(ent);
2454 memcg = mem_cgroup_lookup(id);
2455 if (memcg && !css_tryget(&memcg->css))
2459 unlock_page_cgroup(pc);
2463 static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
2465 unsigned int nr_pages,
2466 enum charge_type ctype,
2469 struct page_cgroup *pc = lookup_page_cgroup(page);
2470 struct zone *uninitialized_var(zone);
2471 struct lruvec *lruvec;
2472 bool was_on_lru = false;
2475 lock_page_cgroup(pc);
2476 if (unlikely(PageCgroupUsed(pc))) {
2477 unlock_page_cgroup(pc);
2478 __mem_cgroup_cancel_charge(memcg, nr_pages);
2482 * we don't need page_cgroup_lock about tail pages, becase they are not
2483 * accessed by any other context at this point.
2487 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2488 * may already be on some other mem_cgroup's LRU. Take care of it.
2491 zone = page_zone(page);
2492 spin_lock_irq(&zone->lru_lock);
2493 if (PageLRU(page)) {
2494 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2496 del_page_from_lru_list(page, lruvec, page_lru(page));
2501 pc->mem_cgroup = memcg;
2503 * We access a page_cgroup asynchronously without lock_page_cgroup().
2504 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2505 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2506 * before USED bit, we need memory barrier here.
2507 * See mem_cgroup_add_lru_list(), etc.
2510 SetPageCgroupUsed(pc);
2514 lruvec = mem_cgroup_zone_lruvec(zone, pc->mem_cgroup);
2515 VM_BUG_ON(PageLRU(page));
2517 add_page_to_lru_list(page, lruvec, page_lru(page));
2519 spin_unlock_irq(&zone->lru_lock);
2522 if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
2527 mem_cgroup_charge_statistics(memcg, anon, nr_pages);
2528 unlock_page_cgroup(pc);
2531 * "charge_statistics" updated event counter. Then, check it.
2532 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2533 * if they exceeds softlimit.
2535 memcg_check_events(memcg, page);
2538 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2540 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
2542 * Because tail pages are not marked as "used", set it. We're under
2543 * zone->lru_lock, 'splitting on pmd' and compound_lock.
2544 * charge/uncharge will be never happen and move_account() is done under
2545 * compound_lock(), so we don't have to take care of races.
2547 void mem_cgroup_split_huge_fixup(struct page *head)
2549 struct page_cgroup *head_pc = lookup_page_cgroup(head);
2550 struct page_cgroup *pc;
2553 if (mem_cgroup_disabled())
2555 for (i = 1; i < HPAGE_PMD_NR; i++) {
2557 pc->mem_cgroup = head_pc->mem_cgroup;
2558 smp_wmb();/* see __commit_charge() */
2559 pc->flags = head_pc->flags & ~PCGF_NOCOPY_AT_SPLIT;
2562 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2565 * mem_cgroup_move_account - move account of the page
2567 * @nr_pages: number of regular pages (>1 for huge pages)
2568 * @pc: page_cgroup of the page.
2569 * @from: mem_cgroup which the page is moved from.
2570 * @to: mem_cgroup which the page is moved to. @from != @to.
2572 * The caller must confirm following.
2573 * - page is not on LRU (isolate_page() is useful.)
2574 * - compound_lock is held when nr_pages > 1
2576 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
2579 static int mem_cgroup_move_account(struct page *page,
2580 unsigned int nr_pages,
2581 struct page_cgroup *pc,
2582 struct mem_cgroup *from,
2583 struct mem_cgroup *to)
2585 unsigned long flags;
2587 bool anon = PageAnon(page);
2589 VM_BUG_ON(from == to);
2590 VM_BUG_ON(PageLRU(page));
2592 * The page is isolated from LRU. So, collapse function
2593 * will not handle this page. But page splitting can happen.
2594 * Do this check under compound_page_lock(). The caller should
2598 if (nr_pages > 1 && !PageTransHuge(page))
2601 lock_page_cgroup(pc);
2604 if (!PageCgroupUsed(pc) || pc->mem_cgroup != from)
2607 move_lock_mem_cgroup(from, &flags);
2609 if (!anon && page_mapped(page)) {
2610 /* Update mapped_file data for mem_cgroup */
2612 __this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2613 __this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
2616 mem_cgroup_charge_statistics(from, anon, -nr_pages);
2618 /* caller should have done css_get */
2619 pc->mem_cgroup = to;
2620 mem_cgroup_charge_statistics(to, anon, nr_pages);
2622 * We charges against "to" which may not have any tasks. Then, "to"
2623 * can be under rmdir(). But in current implementation, caller of
2624 * this function is just force_empty() and move charge, so it's
2625 * guaranteed that "to" is never removed. So, we don't check rmdir
2628 move_unlock_mem_cgroup(from, &flags);
2631 unlock_page_cgroup(pc);
2635 memcg_check_events(to, page);
2636 memcg_check_events(from, page);
2642 * move charges to its parent.
2645 static int mem_cgroup_move_parent(struct page *page,
2646 struct page_cgroup *pc,
2647 struct mem_cgroup *child,
2650 struct mem_cgroup *parent;
2651 unsigned int nr_pages;
2652 unsigned long uninitialized_var(flags);
2656 if (mem_cgroup_is_root(child))
2660 if (!get_page_unless_zero(page))
2662 if (isolate_lru_page(page))
2665 nr_pages = hpage_nr_pages(page);
2667 parent = parent_mem_cgroup(child);
2669 * If no parent, move charges to root cgroup.
2672 parent = root_mem_cgroup;
2675 flags = compound_lock_irqsave(page);
2677 ret = mem_cgroup_move_account(page, nr_pages,
2680 __mem_cgroup_cancel_local_charge(child, nr_pages);
2683 compound_unlock_irqrestore(page, flags);
2684 putback_lru_page(page);
2692 * Charge the memory controller for page usage.
2694 * 0 if the charge was successful
2695 * < 0 if the cgroup is over its limit
2697 static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
2698 gfp_t gfp_mask, enum charge_type ctype)
2700 struct mem_cgroup *memcg = NULL;
2701 unsigned int nr_pages = 1;
2705 if (PageTransHuge(page)) {
2706 nr_pages <<= compound_order(page);
2707 VM_BUG_ON(!PageTransHuge(page));
2709 * Never OOM-kill a process for a huge page. The
2710 * fault handler will fall back to regular pages.
2715 ret = __mem_cgroup_try_charge(mm, gfp_mask, nr_pages, &memcg, oom);
2718 __mem_cgroup_commit_charge(memcg, page, nr_pages, ctype, false);
2722 int mem_cgroup_newpage_charge(struct page *page,
2723 struct mm_struct *mm, gfp_t gfp_mask)
2725 if (mem_cgroup_disabled())
2727 VM_BUG_ON(page_mapped(page));
2728 VM_BUG_ON(page->mapping && !PageAnon(page));
2730 return mem_cgroup_charge_common(page, mm, gfp_mask,
2731 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2735 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr,
2736 enum charge_type ctype);
2738 int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
2741 struct mem_cgroup *memcg = NULL;
2742 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
2745 if (mem_cgroup_disabled())
2747 if (PageCompound(page))
2752 if (!page_is_file_cache(page))
2753 type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
2755 if (!PageSwapCache(page))
2756 ret = mem_cgroup_charge_common(page, mm, gfp_mask, type);
2757 else { /* page is swapcache/shmem */
2758 ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &memcg);
2760 __mem_cgroup_commit_charge_swapin(page, memcg, type);
2766 * While swap-in, try_charge -> commit or cancel, the page is locked.
2767 * And when try_charge() successfully returns, one refcnt to memcg without
2768 * struct page_cgroup is acquired. This refcnt will be consumed by
2769 * "commit()" or removed by "cancel()"
2771 int mem_cgroup_try_charge_swapin(struct mm_struct *mm,
2773 gfp_t mask, struct mem_cgroup **memcgp)
2775 struct mem_cgroup *memcg;
2780 if (mem_cgroup_disabled())
2783 if (!do_swap_account)
2786 * A racing thread's fault, or swapoff, may have already updated
2787 * the pte, and even removed page from swap cache: in those cases
2788 * do_swap_page()'s pte_same() test will fail; but there's also a
2789 * KSM case which does need to charge the page.
2791 if (!PageSwapCache(page))
2793 memcg = try_get_mem_cgroup_from_page(page);
2797 ret = __mem_cgroup_try_charge(NULL, mask, 1, memcgp, true);
2798 css_put(&memcg->css);
2805 ret = __mem_cgroup_try_charge(mm, mask, 1, memcgp, true);
2812 __mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *memcg,
2813 enum charge_type ctype)
2815 if (mem_cgroup_disabled())
2819 cgroup_exclude_rmdir(&memcg->css);
2821 __mem_cgroup_commit_charge(memcg, page, 1, ctype, true);
2823 * Now swap is on-memory. This means this page may be
2824 * counted both as mem and swap....double count.
2825 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2826 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2827 * may call delete_from_swap_cache() before reach here.
2829 if (do_swap_account && PageSwapCache(page)) {
2830 swp_entry_t ent = {.val = page_private(page)};
2831 mem_cgroup_uncharge_swap(ent);
2834 * At swapin, we may charge account against cgroup which has no tasks.
2835 * So, rmdir()->pre_destroy() can be called while we do this charge.
2836 * In that case, we need to call pre_destroy() again. check it here.
2838 cgroup_release_and_wakeup_rmdir(&memcg->css);
2841 void mem_cgroup_commit_charge_swapin(struct page *page,
2842 struct mem_cgroup *memcg)
2844 __mem_cgroup_commit_charge_swapin(page, memcg,
2845 MEM_CGROUP_CHARGE_TYPE_MAPPED);
2848 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup *memcg)
2850 if (mem_cgroup_disabled())
2854 __mem_cgroup_cancel_charge(memcg, 1);
2857 static void mem_cgroup_do_uncharge(struct mem_cgroup *memcg,
2858 unsigned int nr_pages,
2859 const enum charge_type ctype)
2861 struct memcg_batch_info *batch = NULL;
2862 bool uncharge_memsw = true;
2864 /* If swapout, usage of swap doesn't decrease */
2865 if (!do_swap_account || ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT)
2866 uncharge_memsw = false;
2868 batch = ¤t->memcg_batch;
2870 * In usual, we do css_get() when we remember memcg pointer.
2871 * But in this case, we keep res->usage until end of a series of
2872 * uncharges. Then, it's ok to ignore memcg's refcnt.
2875 batch->memcg = memcg;
2877 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2878 * In those cases, all pages freed continuously can be expected to be in
2879 * the same cgroup and we have chance to coalesce uncharges.
2880 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2881 * because we want to do uncharge as soon as possible.
2884 if (!batch->do_batch || test_thread_flag(TIF_MEMDIE))
2885 goto direct_uncharge;
2888 goto direct_uncharge;
2891 * In typical case, batch->memcg == mem. This means we can
2892 * merge a series of uncharges to an uncharge of res_counter.
2893 * If not, we uncharge res_counter ony by one.
2895 if (batch->memcg != memcg)
2896 goto direct_uncharge;
2897 /* remember freed charge and uncharge it later */
2900 batch->memsw_nr_pages++;
2903 res_counter_uncharge(&memcg->res, nr_pages * PAGE_SIZE);
2905 res_counter_uncharge(&memcg->memsw, nr_pages * PAGE_SIZE);
2906 if (unlikely(batch->memcg != memcg))
2907 memcg_oom_recover(memcg);
2911 * uncharge if !page_mapped(page)
2913 static struct mem_cgroup *
2914 __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
2916 struct mem_cgroup *memcg = NULL;
2917 unsigned int nr_pages = 1;
2918 struct page_cgroup *pc;
2921 if (mem_cgroup_disabled())
2924 if (PageSwapCache(page))
2927 if (PageTransHuge(page)) {
2928 nr_pages <<= compound_order(page);
2929 VM_BUG_ON(!PageTransHuge(page));
2932 * Check if our page_cgroup is valid
2934 pc = lookup_page_cgroup(page);
2935 if (unlikely(!PageCgroupUsed(pc)))
2938 lock_page_cgroup(pc);
2940 memcg = pc->mem_cgroup;
2942 if (!PageCgroupUsed(pc))
2945 anon = PageAnon(page);
2948 case MEM_CGROUP_CHARGE_TYPE_MAPPED:
2950 * Generally PageAnon tells if it's the anon statistics to be
2951 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
2952 * used before page reached the stage of being marked PageAnon.
2956 case MEM_CGROUP_CHARGE_TYPE_DROP:
2957 /* See mem_cgroup_prepare_migration() */
2958 if (page_mapped(page) || PageCgroupMigration(pc))
2961 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
2962 if (!PageAnon(page)) { /* Shared memory */
2963 if (page->mapping && !page_is_file_cache(page))
2965 } else if (page_mapped(page)) /* Anon */
2972 mem_cgroup_charge_statistics(memcg, anon, -nr_pages);
2974 ClearPageCgroupUsed(pc);
2976 * pc->mem_cgroup is not cleared here. It will be accessed when it's
2977 * freed from LRU. This is safe because uncharged page is expected not
2978 * to be reused (freed soon). Exception is SwapCache, it's handled by
2979 * special functions.
2982 unlock_page_cgroup(pc);
2984 * even after unlock, we have memcg->res.usage here and this memcg
2985 * will never be freed.
2987 memcg_check_events(memcg, page);
2988 if (do_swap_account && ctype == MEM_CGROUP_CHARGE_TYPE_SWAPOUT) {
2989 mem_cgroup_swap_statistics(memcg, true);
2990 mem_cgroup_get(memcg);
2992 if (!mem_cgroup_is_root(memcg))
2993 mem_cgroup_do_uncharge(memcg, nr_pages, ctype);
2998 unlock_page_cgroup(pc);
3002 void mem_cgroup_uncharge_page(struct page *page)
3005 if (page_mapped(page))
3007 VM_BUG_ON(page->mapping && !PageAnon(page));
3008 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
3011 void mem_cgroup_uncharge_cache_page(struct page *page)
3013 VM_BUG_ON(page_mapped(page));
3014 VM_BUG_ON(page->mapping);
3015 __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
3019 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3020 * In that cases, pages are freed continuously and we can expect pages
3021 * are in the same memcg. All these calls itself limits the number of
3022 * pages freed at once, then uncharge_start/end() is called properly.
3023 * This may be called prural(2) times in a context,
3026 void mem_cgroup_uncharge_start(void)
3028 current->memcg_batch.do_batch++;
3029 /* We can do nest. */
3030 if (current->memcg_batch.do_batch == 1) {
3031 current->memcg_batch.memcg = NULL;
3032 current->memcg_batch.nr_pages = 0;
3033 current->memcg_batch.memsw_nr_pages = 0;
3037 void mem_cgroup_uncharge_end(void)
3039 struct memcg_batch_info *batch = ¤t->memcg_batch;
3041 if (!batch->do_batch)
3045 if (batch->do_batch) /* If stacked, do nothing. */
3051 * This "batch->memcg" is valid without any css_get/put etc...
3052 * bacause we hide charges behind us.
3054 if (batch->nr_pages)
3055 res_counter_uncharge(&batch->memcg->res,
3056 batch->nr_pages * PAGE_SIZE);
3057 if (batch->memsw_nr_pages)
3058 res_counter_uncharge(&batch->memcg->memsw,
3059 batch->memsw_nr_pages * PAGE_SIZE);
3060 memcg_oom_recover(batch->memcg);
3061 /* forget this pointer (for sanity check) */
3062 batch->memcg = NULL;
3067 * called after __delete_from_swap_cache() and drop "page" account.
3068 * memcg information is recorded to swap_cgroup of "ent"
3071 mem_cgroup_uncharge_swapcache(struct page *page, swp_entry_t ent, bool swapout)
3073 struct mem_cgroup *memcg;
3074 int ctype = MEM_CGROUP_CHARGE_TYPE_SWAPOUT;
3076 if (!swapout) /* this was a swap cache but the swap is unused ! */
3077 ctype = MEM_CGROUP_CHARGE_TYPE_DROP;
3079 memcg = __mem_cgroup_uncharge_common(page, ctype);
3082 * record memcg information, if swapout && memcg != NULL,
3083 * mem_cgroup_get() was called in uncharge().
3085 if (do_swap_account && swapout && memcg)
3086 swap_cgroup_record(ent, css_id(&memcg->css));
3090 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
3092 * called from swap_entry_free(). remove record in swap_cgroup and
3093 * uncharge "memsw" account.
3095 void mem_cgroup_uncharge_swap(swp_entry_t ent)
3097 struct mem_cgroup *memcg;
3100 if (!do_swap_account)
3103 id = swap_cgroup_record(ent, 0);
3105 memcg = mem_cgroup_lookup(id);
3108 * We uncharge this because swap is freed.
3109 * This memcg can be obsolete one. We avoid calling css_tryget
3111 if (!mem_cgroup_is_root(memcg))
3112 res_counter_uncharge(&memcg->memsw, PAGE_SIZE);
3113 mem_cgroup_swap_statistics(memcg, false);
3114 mem_cgroup_put(memcg);
3120 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3121 * @entry: swap entry to be moved
3122 * @from: mem_cgroup which the entry is moved from
3123 * @to: mem_cgroup which the entry is moved to
3125 * It succeeds only when the swap_cgroup's record for this entry is the same
3126 * as the mem_cgroup's id of @from.
3128 * Returns 0 on success, -EINVAL on failure.
3130 * The caller must have charged to @to, IOW, called res_counter_charge() about
3131 * both res and memsw, and called css_get().
3133 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3134 struct mem_cgroup *from, struct mem_cgroup *to)
3136 unsigned short old_id, new_id;
3138 old_id = css_id(&from->css);
3139 new_id = css_id(&to->css);
3141 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3142 mem_cgroup_swap_statistics(from, false);
3143 mem_cgroup_swap_statistics(to, true);
3145 * This function is only called from task migration context now.
3146 * It postpones res_counter and refcount handling till the end
3147 * of task migration(mem_cgroup_clear_mc()) for performance
3148 * improvement. But we cannot postpone mem_cgroup_get(to)
3149 * because if the process that has been moved to @to does
3150 * swap-in, the refcount of @to might be decreased to 0.
3158 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3159 struct mem_cgroup *from, struct mem_cgroup *to)
3166 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
3169 int mem_cgroup_prepare_migration(struct page *page,
3170 struct page *newpage, struct mem_cgroup **memcgp, gfp_t gfp_mask)
3172 struct mem_cgroup *memcg = NULL;
3173 struct page_cgroup *pc;
3174 enum charge_type ctype;
3179 VM_BUG_ON(PageTransHuge(page));
3180 if (mem_cgroup_disabled())
3183 pc = lookup_page_cgroup(page);
3184 lock_page_cgroup(pc);
3185 if (PageCgroupUsed(pc)) {
3186 memcg = pc->mem_cgroup;
3187 css_get(&memcg->css);
3189 * At migrating an anonymous page, its mapcount goes down
3190 * to 0 and uncharge() will be called. But, even if it's fully
3191 * unmapped, migration may fail and this page has to be
3192 * charged again. We set MIGRATION flag here and delay uncharge
3193 * until end_migration() is called
3195 * Corner Case Thinking
3197 * When the old page was mapped as Anon and it's unmap-and-freed
3198 * while migration was ongoing.
3199 * If unmap finds the old page, uncharge() of it will be delayed
3200 * until end_migration(). If unmap finds a new page, it's
3201 * uncharged when it make mapcount to be 1->0. If unmap code
3202 * finds swap_migration_entry, the new page will not be mapped
3203 * and end_migration() will find it(mapcount==0).
3206 * When the old page was mapped but migraion fails, the kernel
3207 * remaps it. A charge for it is kept by MIGRATION flag even
3208 * if mapcount goes down to 0. We can do remap successfully
3209 * without charging it again.
3212 * The "old" page is under lock_page() until the end of
3213 * migration, so, the old page itself will not be swapped-out.
3214 * If the new page is swapped out before end_migraton, our
3215 * hook to usual swap-out path will catch the event.
3218 SetPageCgroupMigration(pc);
3220 unlock_page_cgroup(pc);
3222 * If the page is not charged at this point,
3229 ret = __mem_cgroup_try_charge(NULL, gfp_mask, 1, memcgp, false);
3230 css_put(&memcg->css);/* drop extra refcnt */
3232 if (PageAnon(page)) {
3233 lock_page_cgroup(pc);
3234 ClearPageCgroupMigration(pc);
3235 unlock_page_cgroup(pc);
3237 * The old page may be fully unmapped while we kept it.
3239 mem_cgroup_uncharge_page(page);
3241 /* we'll need to revisit this error code (we have -EINTR) */
3245 * We charge new page before it's used/mapped. So, even if unlock_page()
3246 * is called before end_migration, we can catch all events on this new
3247 * page. In the case new page is migrated but not remapped, new page's
3248 * mapcount will be finally 0 and we call uncharge in end_migration().
3251 ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
3252 else if (page_is_file_cache(page))
3253 ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
3255 ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3256 __mem_cgroup_commit_charge(memcg, newpage, 1, ctype, false);
3260 /* remove redundant charge if migration failed*/
3261 void mem_cgroup_end_migration(struct mem_cgroup *memcg,
3262 struct page *oldpage, struct page *newpage, bool migration_ok)
3264 struct page *used, *unused;
3265 struct page_cgroup *pc;
3270 /* blocks rmdir() */
3271 cgroup_exclude_rmdir(&memcg->css);
3272 if (!migration_ok) {
3280 * We disallowed uncharge of pages under migration because mapcount
3281 * of the page goes down to zero, temporarly.
3282 * Clear the flag and check the page should be charged.
3284 pc = lookup_page_cgroup(oldpage);
3285 lock_page_cgroup(pc);
3286 ClearPageCgroupMigration(pc);
3287 unlock_page_cgroup(pc);
3288 anon = PageAnon(used);
3289 __mem_cgroup_uncharge_common(unused,
3290 anon ? MEM_CGROUP_CHARGE_TYPE_MAPPED
3291 : MEM_CGROUP_CHARGE_TYPE_CACHE);
3294 * If a page is a file cache, radix-tree replacement is very atomic
3295 * and we can skip this check. When it was an Anon page, its mapcount
3296 * goes down to 0. But because we added MIGRATION flage, it's not
3297 * uncharged yet. There are several case but page->mapcount check
3298 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3299 * check. (see prepare_charge() also)
3302 mem_cgroup_uncharge_page(used);
3304 * At migration, we may charge account against cgroup which has no
3306 * So, rmdir()->pre_destroy() can be called while we do this charge.
3307 * In that case, we need to call pre_destroy() again. check it here.
3309 cgroup_release_and_wakeup_rmdir(&memcg->css);
3313 * At replace page cache, newpage is not under any memcg but it's on
3314 * LRU. So, this function doesn't touch res_counter but handles LRU
3315 * in correct way. Both pages are locked so we cannot race with uncharge.
3317 void mem_cgroup_replace_page_cache(struct page *oldpage,
3318 struct page *newpage)
3320 struct mem_cgroup *memcg = NULL;
3321 struct page_cgroup *pc;
3322 enum charge_type type = MEM_CGROUP_CHARGE_TYPE_CACHE;
3324 if (mem_cgroup_disabled())
3327 pc = lookup_page_cgroup(oldpage);
3328 /* fix accounting on old pages */
3329 lock_page_cgroup(pc);
3330 if (PageCgroupUsed(pc)) {
3331 memcg = pc->mem_cgroup;
3332 mem_cgroup_charge_statistics(memcg, false, -1);
3333 ClearPageCgroupUsed(pc);
3335 unlock_page_cgroup(pc);
3338 * When called from shmem_replace_page(), in some cases the
3339 * oldpage has already been charged, and in some cases not.
3344 if (PageSwapBacked(oldpage))
3345 type = MEM_CGROUP_CHARGE_TYPE_SHMEM;
3348 * Even if newpage->mapping was NULL before starting replacement,
3349 * the newpage may be on LRU(or pagevec for LRU) already. We lock
3350 * LRU while we overwrite pc->mem_cgroup.
3352 __mem_cgroup_commit_charge(memcg, newpage, 1, type, true);
3355 #ifdef CONFIG_DEBUG_VM
3356 static struct page_cgroup *lookup_page_cgroup_used(struct page *page)
3358 struct page_cgroup *pc;
3360 pc = lookup_page_cgroup(page);
3362 * Can be NULL while feeding pages into the page allocator for
3363 * the first time, i.e. during boot or memory hotplug;
3364 * or when mem_cgroup_disabled().
3366 if (likely(pc) && PageCgroupUsed(pc))
3371 bool mem_cgroup_bad_page_check(struct page *page)
3373 if (mem_cgroup_disabled())
3376 return lookup_page_cgroup_used(page) != NULL;
3379 void mem_cgroup_print_bad_page(struct page *page)
3381 struct page_cgroup *pc;
3383 pc = lookup_page_cgroup_used(page);
3385 printk(KERN_ALERT "pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
3386 pc, pc->flags, pc->mem_cgroup);
3391 static DEFINE_MUTEX(set_limit_mutex);
3393 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
3394 unsigned long long val)
3397 u64 memswlimit, memlimit;
3399 int children = mem_cgroup_count_children(memcg);
3400 u64 curusage, oldusage;
3404 * For keeping hierarchical_reclaim simple, how long we should retry
3405 * is depends on callers. We set our retry-count to be function
3406 * of # of children which we should visit in this loop.
3408 retry_count = MEM_CGROUP_RECLAIM_RETRIES * children;
3410 oldusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3413 while (retry_count) {
3414 if (signal_pending(current)) {
3419 * Rather than hide all in some function, I do this in
3420 * open coded manner. You see what this really does.
3421 * We have to guarantee memcg->res.limit < memcg->memsw.limit.
3423 mutex_lock(&set_limit_mutex);
3424 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3425 if (memswlimit < val) {
3427 mutex_unlock(&set_limit_mutex);
3431 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3435 ret = res_counter_set_limit(&memcg->res, val);
3437 if (memswlimit == val)
3438 memcg->memsw_is_minimum = true;
3440 memcg->memsw_is_minimum = false;
3442 mutex_unlock(&set_limit_mutex);
3447 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3448 MEM_CGROUP_RECLAIM_SHRINK);
3449 curusage = res_counter_read_u64(&memcg->res, RES_USAGE);
3450 /* Usage is reduced ? */
3451 if (curusage >= oldusage)
3454 oldusage = curusage;
3456 if (!ret && enlarge)
3457 memcg_oom_recover(memcg);
3462 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
3463 unsigned long long val)
3466 u64 memlimit, memswlimit, oldusage, curusage;
3467 int children = mem_cgroup_count_children(memcg);
3471 /* see mem_cgroup_resize_res_limit */
3472 retry_count = children * MEM_CGROUP_RECLAIM_RETRIES;
3473 oldusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3474 while (retry_count) {
3475 if (signal_pending(current)) {
3480 * Rather than hide all in some function, I do this in
3481 * open coded manner. You see what this really does.
3482 * We have to guarantee memcg->res.limit < memcg->memsw.limit.
3484 mutex_lock(&set_limit_mutex);
3485 memlimit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3486 if (memlimit > val) {
3488 mutex_unlock(&set_limit_mutex);
3491 memswlimit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3492 if (memswlimit < val)
3494 ret = res_counter_set_limit(&memcg->memsw, val);
3496 if (memlimit == val)
3497 memcg->memsw_is_minimum = true;
3499 memcg->memsw_is_minimum = false;
3501 mutex_unlock(&set_limit_mutex);
3506 mem_cgroup_reclaim(memcg, GFP_KERNEL,
3507 MEM_CGROUP_RECLAIM_NOSWAP |
3508 MEM_CGROUP_RECLAIM_SHRINK);
3509 curusage = res_counter_read_u64(&memcg->memsw, RES_USAGE);
3510 /* Usage is reduced ? */
3511 if (curusage >= oldusage)
3514 oldusage = curusage;
3516 if (!ret && enlarge)
3517 memcg_oom_recover(memcg);
3521 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
3523 unsigned long *total_scanned)
3525 unsigned long nr_reclaimed = 0;
3526 struct mem_cgroup_per_zone *mz, *next_mz = NULL;
3527 unsigned long reclaimed;
3529 struct mem_cgroup_tree_per_zone *mctz;
3530 unsigned long long excess;
3531 unsigned long nr_scanned;
3536 mctz = soft_limit_tree_node_zone(zone_to_nid(zone), zone_idx(zone));
3538 * This loop can run a while, specially if mem_cgroup's continuously
3539 * keep exceeding their soft limit and putting the system under
3546 mz = mem_cgroup_largest_soft_limit_node(mctz);
3551 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, zone,
3552 gfp_mask, &nr_scanned);
3553 nr_reclaimed += reclaimed;
3554 *total_scanned += nr_scanned;
3555 spin_lock(&mctz->lock);
3558 * If we failed to reclaim anything from this memory cgroup
3559 * it is time to move on to the next cgroup
3565 * Loop until we find yet another one.
3567 * By the time we get the soft_limit lock
3568 * again, someone might have aded the
3569 * group back on the RB tree. Iterate to
3570 * make sure we get a different mem.
3571 * mem_cgroup_largest_soft_limit_node returns
3572 * NULL if no other cgroup is present on
3576 __mem_cgroup_largest_soft_limit_node(mctz);
3578 css_put(&next_mz->memcg->css);
3579 else /* next_mz == NULL or other memcg */
3583 __mem_cgroup_remove_exceeded(mz->memcg, mz, mctz);
3584 excess = res_counter_soft_limit_excess(&mz->memcg->res);
3586 * One school of thought says that we should not add
3587 * back the node to the tree if reclaim returns 0.
3588 * But our reclaim could return 0, simply because due
3589 * to priority we are exposing a smaller subset of
3590 * memory to reclaim from. Consider this as a longer
3593 /* If excess == 0, no tree ops */
3594 __mem_cgroup_insert_exceeded(mz->memcg, mz, mctz, excess);
3595 spin_unlock(&mctz->lock);
3596 css_put(&mz->memcg->css);
3599 * Could not reclaim anything and there are no more
3600 * mem cgroups to try or we seem to be looping without
3601 * reclaiming anything.
3603 if (!nr_reclaimed &&
3605 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3607 } while (!nr_reclaimed);
3609 css_put(&next_mz->memcg->css);
3610 return nr_reclaimed;
3614 * This routine traverse page_cgroup in given list and drop them all.
3615 * *And* this routine doesn't reclaim page itself, just removes page_cgroup.
3617 static int mem_cgroup_force_empty_list(struct mem_cgroup *memcg,
3618 int node, int zid, enum lru_list lru)
3620 struct mem_cgroup_per_zone *mz;
3621 unsigned long flags, loop;
3622 struct list_head *list;
3627 zone = &NODE_DATA(node)->node_zones[zid];
3628 mz = mem_cgroup_zoneinfo(memcg, node, zid);
3629 list = &mz->lruvec.lists[lru];
3631 loop = mz->lru_size[lru];
3632 /* give some margin against EBUSY etc...*/
3636 struct page_cgroup *pc;
3640 spin_lock_irqsave(&zone->lru_lock, flags);
3641 if (list_empty(list)) {
3642 spin_unlock_irqrestore(&zone->lru_lock, flags);
3645 page = list_entry(list->prev, struct page, lru);
3647 list_move(&page->lru, list);
3649 spin_unlock_irqrestore(&zone->lru_lock, flags);
3652 spin_unlock_irqrestore(&zone->lru_lock, flags);
3654 pc = lookup_page_cgroup(page);
3656 ret = mem_cgroup_move_parent(page, pc, memcg, GFP_KERNEL);
3657 if (ret == -ENOMEM || ret == -EINTR)
3660 if (ret == -EBUSY || ret == -EINVAL) {
3661 /* found lock contention or "pc" is obsolete. */
3668 if (!ret && !list_empty(list))
3674 * make mem_cgroup's charge to be 0 if there is no task.
3675 * This enables deleting this mem_cgroup.
3677 static int mem_cgroup_force_empty(struct mem_cgroup *memcg, bool free_all)
3680 int node, zid, shrink;
3681 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3682 struct cgroup *cgrp = memcg->css.cgroup;
3684 css_get(&memcg->css);
3687 /* should free all ? */
3693 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children))
3696 if (signal_pending(current))
3698 /* This is for making all *used* pages to be on LRU. */
3699 lru_add_drain_all();
3700 drain_all_stock_sync(memcg);
3702 mem_cgroup_start_move(memcg);
3703 for_each_node_state(node, N_HIGH_MEMORY) {
3704 for (zid = 0; !ret && zid < MAX_NR_ZONES; zid++) {
3707 ret = mem_cgroup_force_empty_list(memcg,
3716 mem_cgroup_end_move(memcg);
3717 memcg_oom_recover(memcg);
3718 /* it seems parent cgroup doesn't have enough mem */
3722 /* "ret" should also be checked to ensure all lists are empty. */
3723 } while (res_counter_read_u64(&memcg->res, RES_USAGE) > 0 || ret);
3725 css_put(&memcg->css);
3729 /* returns EBUSY if there is a task or if we come here twice. */
3730 if (cgroup_task_count(cgrp) || !list_empty(&cgrp->children) || shrink) {
3734 /* we call try-to-free pages for make this cgroup empty */
3735 lru_add_drain_all();
3736 /* try to free all pages in this cgroup */
3738 while (nr_retries && res_counter_read_u64(&memcg->res, RES_USAGE) > 0) {
3741 if (signal_pending(current)) {
3745 progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL,
3749 /* maybe some writeback is necessary */
3750 congestion_wait(BLK_RW_ASYNC, HZ/10);
3755 /* try move_account...there may be some *locked* pages. */
3759 static int mem_cgroup_force_empty_write(struct cgroup *cont, unsigned int event)
3761 return mem_cgroup_force_empty(mem_cgroup_from_cont(cont), true);
3765 static u64 mem_cgroup_hierarchy_read(struct cgroup *cont, struct cftype *cft)
3767 return mem_cgroup_from_cont(cont)->use_hierarchy;
3770 static int mem_cgroup_hierarchy_write(struct cgroup *cont, struct cftype *cft,
3774 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3775 struct cgroup *parent = cont->parent;
3776 struct mem_cgroup *parent_memcg = NULL;
3779 parent_memcg = mem_cgroup_from_cont(parent);
3783 * If parent's use_hierarchy is set, we can't make any modifications
3784 * in the child subtrees. If it is unset, then the change can
3785 * occur, provided the current cgroup has no children.
3787 * For the root cgroup, parent_mem is NULL, we allow value to be
3788 * set if there are no children.
3790 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3791 (val == 1 || val == 0)) {
3792 if (list_empty(&cont->children))
3793 memcg->use_hierarchy = val;
3804 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup *memcg,
3805 enum mem_cgroup_stat_index idx)
3807 struct mem_cgroup *iter;
3810 /* Per-cpu values can be negative, use a signed accumulator */
3811 for_each_mem_cgroup_tree(iter, memcg)
3812 val += mem_cgroup_read_stat(iter, idx);
3814 if (val < 0) /* race ? */
3819 static inline u64 mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3823 if (!mem_cgroup_is_root(memcg)) {
3825 return res_counter_read_u64(&memcg->res, RES_USAGE);
3827 return res_counter_read_u64(&memcg->memsw, RES_USAGE);
3830 val = mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_CACHE);
3831 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_RSS);
3834 val += mem_cgroup_recursive_stat(memcg, MEM_CGROUP_STAT_SWAPOUT);
3836 return val << PAGE_SHIFT;
3839 static ssize_t mem_cgroup_read(struct cgroup *cont, struct cftype *cft,
3840 struct file *file, char __user *buf,
3841 size_t nbytes, loff_t *ppos)
3843 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3846 int type, name, len;
3848 type = MEMFILE_TYPE(cft->private);
3849 name = MEMFILE_ATTR(cft->private);
3851 if (!do_swap_account && type == _MEMSWAP)
3856 if (name == RES_USAGE)
3857 val = mem_cgroup_usage(memcg, false);
3859 val = res_counter_read_u64(&memcg->res, name);
3862 if (name == RES_USAGE)
3863 val = mem_cgroup_usage(memcg, true);
3865 val = res_counter_read_u64(&memcg->memsw, name);
3871 len = scnprintf(str, sizeof(str), "%llu\n", (unsigned long long)val);
3872 return simple_read_from_buffer(buf, nbytes, ppos, str, len);
3875 * The user of this function is...
3878 static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
3881 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3883 unsigned long long val;
3886 type = MEMFILE_TYPE(cft->private);
3887 name = MEMFILE_ATTR(cft->private);
3889 if (!do_swap_account && type == _MEMSWAP)
3894 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3898 /* This function does all necessary parse...reuse it */
3899 ret = res_counter_memparse_write_strategy(buffer, &val);
3903 ret = mem_cgroup_resize_limit(memcg, val);
3905 ret = mem_cgroup_resize_memsw_limit(memcg, val);
3907 case RES_SOFT_LIMIT:
3908 ret = res_counter_memparse_write_strategy(buffer, &val);
3912 * For memsw, soft limits are hard to implement in terms
3913 * of semantics, for now, we support soft limits for
3914 * control without swap
3917 ret = res_counter_set_soft_limit(&memcg->res, val);
3922 ret = -EINVAL; /* should be BUG() ? */
3928 static void memcg_get_hierarchical_limit(struct mem_cgroup *memcg,
3929 unsigned long long *mem_limit, unsigned long long *memsw_limit)
3931 struct cgroup *cgroup;
3932 unsigned long long min_limit, min_memsw_limit, tmp;
3934 min_limit = res_counter_read_u64(&memcg->res, RES_LIMIT);
3935 min_memsw_limit = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3936 cgroup = memcg->css.cgroup;
3937 if (!memcg->use_hierarchy)
3940 while (cgroup->parent) {
3941 cgroup = cgroup->parent;
3942 memcg = mem_cgroup_from_cont(cgroup);
3943 if (!memcg->use_hierarchy)
3945 tmp = res_counter_read_u64(&memcg->res, RES_LIMIT);
3946 min_limit = min(min_limit, tmp);
3947 tmp = res_counter_read_u64(&memcg->memsw, RES_LIMIT);
3948 min_memsw_limit = min(min_memsw_limit, tmp);
3951 *mem_limit = min_limit;
3952 *memsw_limit = min_memsw_limit;
3955 static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
3957 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
3960 type = MEMFILE_TYPE(event);
3961 name = MEMFILE_ATTR(event);
3963 if (!do_swap_account && type == _MEMSWAP)
3969 res_counter_reset_max(&memcg->res);
3971 res_counter_reset_max(&memcg->memsw);
3975 res_counter_reset_failcnt(&memcg->res);
3977 res_counter_reset_failcnt(&memcg->memsw);
3984 static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
3987 return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
3991 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
3992 struct cftype *cft, u64 val)
3994 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
3996 if (val >= (1 << NR_MOVE_TYPE))
3999 * We check this value several times in both in can_attach() and
4000 * attach(), so we need cgroup lock to prevent this value from being
4004 memcg->move_charge_at_immigrate = val;
4010 static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
4011 struct cftype *cft, u64 val)
4018 static int mem_control_numa_stat_show(struct cgroup *cont, struct cftype *cft,
4022 unsigned long total_nr, file_nr, anon_nr, unevictable_nr;
4023 unsigned long node_nr;
4024 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4026 total_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL);
4027 seq_printf(m, "total=%lu", total_nr);
4028 for_each_node_state(nid, N_HIGH_MEMORY) {
4029 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL);
4030 seq_printf(m, " N%d=%lu", nid, node_nr);
4034 file_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_FILE);
4035 seq_printf(m, "file=%lu", file_nr);
4036 for_each_node_state(nid, N_HIGH_MEMORY) {
4037 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4039 seq_printf(m, " N%d=%lu", nid, node_nr);
4043 anon_nr = mem_cgroup_nr_lru_pages(memcg, LRU_ALL_ANON);
4044 seq_printf(m, "anon=%lu", anon_nr);
4045 for_each_node_state(nid, N_HIGH_MEMORY) {
4046 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4048 seq_printf(m, " N%d=%lu", nid, node_nr);
4052 unevictable_nr = mem_cgroup_nr_lru_pages(memcg, BIT(LRU_UNEVICTABLE));
4053 seq_printf(m, "unevictable=%lu", unevictable_nr);
4054 for_each_node_state(nid, N_HIGH_MEMORY) {
4055 node_nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
4056 BIT(LRU_UNEVICTABLE));
4057 seq_printf(m, " N%d=%lu", nid, node_nr);
4062 #endif /* CONFIG_NUMA */
4064 static const char * const mem_cgroup_lru_names[] = {
4072 static inline void mem_cgroup_lru_names_not_uptodate(void)
4074 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
4077 static int mem_control_stat_show(struct cgroup *cont, struct cftype *cft,
4080 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4081 struct mem_cgroup *mi;
4084 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4085 if (i == MEM_CGROUP_STAT_SWAPOUT && !do_swap_account)
4087 seq_printf(m, "%s %ld\n", mem_cgroup_stat_names[i],
4088 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
4091 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
4092 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
4093 mem_cgroup_read_events(memcg, i));
4095 for (i = 0; i < NR_LRU_LISTS; i++)
4096 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
4097 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
4099 /* Hierarchical information */
4101 unsigned long long limit, memsw_limit;
4102 memcg_get_hierarchical_limit(memcg, &limit, &memsw_limit);
4103 seq_printf(m, "hierarchical_memory_limit %llu\n", limit);
4104 if (do_swap_account)
4105 seq_printf(m, "hierarchical_memsw_limit %llu\n",
4109 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
4112 if (i == MEM_CGROUP_STAT_SWAPOUT && !do_swap_account)
4114 for_each_mem_cgroup_tree(mi, memcg)
4115 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
4116 seq_printf(m, "total_%s %lld\n", mem_cgroup_stat_names[i], val);
4119 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
4120 unsigned long long val = 0;
4122 for_each_mem_cgroup_tree(mi, memcg)
4123 val += mem_cgroup_read_events(mi, i);
4124 seq_printf(m, "total_%s %llu\n",
4125 mem_cgroup_events_names[i], val);
4128 for (i = 0; i < NR_LRU_LISTS; i++) {
4129 unsigned long long val = 0;
4131 for_each_mem_cgroup_tree(mi, memcg)
4132 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
4133 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
4136 #ifdef CONFIG_DEBUG_VM
4139 struct mem_cgroup_per_zone *mz;
4140 struct zone_reclaim_stat *rstat;
4141 unsigned long recent_rotated[2] = {0, 0};
4142 unsigned long recent_scanned[2] = {0, 0};
4144 for_each_online_node(nid)
4145 for (zid = 0; zid < MAX_NR_ZONES; zid++) {
4146 mz = mem_cgroup_zoneinfo(memcg, nid, zid);
4147 rstat = &mz->lruvec.reclaim_stat;
4149 recent_rotated[0] += rstat->recent_rotated[0];
4150 recent_rotated[1] += rstat->recent_rotated[1];
4151 recent_scanned[0] += rstat->recent_scanned[0];
4152 recent_scanned[1] += rstat->recent_scanned[1];
4154 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
4155 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
4156 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
4157 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
4164 static u64 mem_cgroup_swappiness_read(struct cgroup *cgrp, struct cftype *cft)
4166 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4168 return mem_cgroup_swappiness(memcg);
4171 static int mem_cgroup_swappiness_write(struct cgroup *cgrp, struct cftype *cft,
4174 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4175 struct mem_cgroup *parent;
4180 if (cgrp->parent == NULL)
4183 parent = mem_cgroup_from_cont(cgrp->parent);
4187 /* If under hierarchy, only empty-root can set this value */
4188 if ((parent->use_hierarchy) ||
4189 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4194 memcg->swappiness = val;
4201 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
4203 struct mem_cgroup_threshold_ary *t;
4209 t = rcu_dereference(memcg->thresholds.primary);
4211 t = rcu_dereference(memcg->memsw_thresholds.primary);
4216 usage = mem_cgroup_usage(memcg, swap);
4219 * current_threshold points to threshold just below or equal to usage.
4220 * If it's not true, a threshold was crossed after last
4221 * call of __mem_cgroup_threshold().
4223 i = t->current_threshold;
4226 * Iterate backward over array of thresholds starting from
4227 * current_threshold and check if a threshold is crossed.
4228 * If none of thresholds below usage is crossed, we read
4229 * only one element of the array here.
4231 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
4232 eventfd_signal(t->entries[i].eventfd, 1);
4234 /* i = current_threshold + 1 */
4238 * Iterate forward over array of thresholds starting from
4239 * current_threshold+1 and check if a threshold is crossed.
4240 * If none of thresholds above usage is crossed, we read
4241 * only one element of the array here.
4243 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
4244 eventfd_signal(t->entries[i].eventfd, 1);
4246 /* Update current_threshold */
4247 t->current_threshold = i - 1;
4252 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
4255 __mem_cgroup_threshold(memcg, false);
4256 if (do_swap_account)
4257 __mem_cgroup_threshold(memcg, true);
4259 memcg = parent_mem_cgroup(memcg);
4263 static int compare_thresholds(const void *a, const void *b)
4265 const struct mem_cgroup_threshold *_a = a;
4266 const struct mem_cgroup_threshold *_b = b;
4268 return _a->threshold - _b->threshold;
4271 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
4273 struct mem_cgroup_eventfd_list *ev;
4275 list_for_each_entry(ev, &memcg->oom_notify, list)
4276 eventfd_signal(ev->eventfd, 1);
4280 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
4282 struct mem_cgroup *iter;
4284 for_each_mem_cgroup_tree(iter, memcg)
4285 mem_cgroup_oom_notify_cb(iter);
4288 static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
4289 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4291 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4292 struct mem_cgroup_thresholds *thresholds;
4293 struct mem_cgroup_threshold_ary *new;
4294 int type = MEMFILE_TYPE(cft->private);
4295 u64 threshold, usage;
4298 ret = res_counter_memparse_write_strategy(args, &threshold);
4302 mutex_lock(&memcg->thresholds_lock);
4305 thresholds = &memcg->thresholds;
4306 else if (type == _MEMSWAP)
4307 thresholds = &memcg->memsw_thresholds;
4311 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4313 /* Check if a threshold crossed before adding a new one */
4314 if (thresholds->primary)
4315 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4317 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4319 /* Allocate memory for new array of thresholds */
4320 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
4328 /* Copy thresholds (if any) to new array */
4329 if (thresholds->primary) {
4330 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4331 sizeof(struct mem_cgroup_threshold));
4334 /* Add new threshold */
4335 new->entries[size - 1].eventfd = eventfd;
4336 new->entries[size - 1].threshold = threshold;
4338 /* Sort thresholds. Registering of new threshold isn't time-critical */
4339 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4340 compare_thresholds, NULL);
4342 /* Find current threshold */
4343 new->current_threshold = -1;
4344 for (i = 0; i < size; i++) {
4345 if (new->entries[i].threshold <= usage) {
4347 * new->current_threshold will not be used until
4348 * rcu_assign_pointer(), so it's safe to increment
4351 ++new->current_threshold;
4356 /* Free old spare buffer and save old primary buffer as spare */
4357 kfree(thresholds->spare);
4358 thresholds->spare = thresholds->primary;
4360 rcu_assign_pointer(thresholds->primary, new);
4362 /* To be sure that nobody uses thresholds */
4366 mutex_unlock(&memcg->thresholds_lock);
4371 static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
4372 struct cftype *cft, struct eventfd_ctx *eventfd)
4374 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4375 struct mem_cgroup_thresholds *thresholds;
4376 struct mem_cgroup_threshold_ary *new;
4377 int type = MEMFILE_TYPE(cft->private);
4381 mutex_lock(&memcg->thresholds_lock);
4383 thresholds = &memcg->thresholds;
4384 else if (type == _MEMSWAP)
4385 thresholds = &memcg->memsw_thresholds;
4389 if (!thresholds->primary)
4392 usage = mem_cgroup_usage(memcg, type == _MEMSWAP);
4394 /* Check if a threshold crossed before removing */
4395 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4397 /* Calculate new number of threshold */
4399 for (i = 0; i < thresholds->primary->size; i++) {
4400 if (thresholds->primary->entries[i].eventfd != eventfd)
4404 new = thresholds->spare;
4406 /* Set thresholds array to NULL if we don't have thresholds */
4415 /* Copy thresholds and find current threshold */
4416 new->current_threshold = -1;
4417 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4418 if (thresholds->primary->entries[i].eventfd == eventfd)
4421 new->entries[j] = thresholds->primary->entries[i];
4422 if (new->entries[j].threshold <= usage) {
4424 * new->current_threshold will not be used
4425 * until rcu_assign_pointer(), so it's safe to increment
4428 ++new->current_threshold;
4434 /* Swap primary and spare array */
4435 thresholds->spare = thresholds->primary;
4436 /* If all events are unregistered, free the spare array */
4438 kfree(thresholds->spare);
4439 thresholds->spare = NULL;
4442 rcu_assign_pointer(thresholds->primary, new);
4444 /* To be sure that nobody uses thresholds */
4447 mutex_unlock(&memcg->thresholds_lock);
4450 static int mem_cgroup_oom_register_event(struct cgroup *cgrp,
4451 struct cftype *cft, struct eventfd_ctx *eventfd, const char *args)
4453 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4454 struct mem_cgroup_eventfd_list *event;
4455 int type = MEMFILE_TYPE(cft->private);
4457 BUG_ON(type != _OOM_TYPE);
4458 event = kmalloc(sizeof(*event), GFP_KERNEL);
4462 spin_lock(&memcg_oom_lock);
4464 event->eventfd = eventfd;
4465 list_add(&event->list, &memcg->oom_notify);
4467 /* already in OOM ? */
4468 if (atomic_read(&memcg->under_oom))
4469 eventfd_signal(eventfd, 1);
4470 spin_unlock(&memcg_oom_lock);
4475 static void mem_cgroup_oom_unregister_event(struct cgroup *cgrp,
4476 struct cftype *cft, struct eventfd_ctx *eventfd)
4478 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4479 struct mem_cgroup_eventfd_list *ev, *tmp;
4480 int type = MEMFILE_TYPE(cft->private);
4482 BUG_ON(type != _OOM_TYPE);
4484 spin_lock(&memcg_oom_lock);
4486 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4487 if (ev->eventfd == eventfd) {
4488 list_del(&ev->list);
4493 spin_unlock(&memcg_oom_lock);
4496 static int mem_cgroup_oom_control_read(struct cgroup *cgrp,
4497 struct cftype *cft, struct cgroup_map_cb *cb)
4499 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4501 cb->fill(cb, "oom_kill_disable", memcg->oom_kill_disable);
4503 if (atomic_read(&memcg->under_oom))
4504 cb->fill(cb, "under_oom", 1);
4506 cb->fill(cb, "under_oom", 0);
4510 static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
4511 struct cftype *cft, u64 val)
4513 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
4514 struct mem_cgroup *parent;
4516 /* cannot set to root cgroup and only 0 and 1 are allowed */
4517 if (!cgrp->parent || !((val == 0) || (val == 1)))
4520 parent = mem_cgroup_from_cont(cgrp->parent);
4523 /* oom-kill-disable is a flag for subhierarchy. */
4524 if ((parent->use_hierarchy) ||
4525 (memcg->use_hierarchy && !list_empty(&cgrp->children))) {
4529 memcg->oom_kill_disable = val;
4531 memcg_oom_recover(memcg);
4536 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
4537 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4539 return mem_cgroup_sockets_init(memcg, ss);
4542 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
4544 mem_cgroup_sockets_destroy(memcg);
4547 static int memcg_init_kmem(struct mem_cgroup *memcg, struct cgroup_subsys *ss)
4552 static void kmem_cgroup_destroy(struct mem_cgroup *memcg)
4557 static struct cftype mem_cgroup_files[] = {
4559 .name = "usage_in_bytes",
4560 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4561 .read = mem_cgroup_read,
4562 .register_event = mem_cgroup_usage_register_event,
4563 .unregister_event = mem_cgroup_usage_unregister_event,
4566 .name = "max_usage_in_bytes",
4567 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4568 .trigger = mem_cgroup_reset,
4569 .read = mem_cgroup_read,
4572 .name = "limit_in_bytes",
4573 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4574 .write_string = mem_cgroup_write,
4575 .read = mem_cgroup_read,
4578 .name = "soft_limit_in_bytes",
4579 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4580 .write_string = mem_cgroup_write,
4581 .read = mem_cgroup_read,
4585 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4586 .trigger = mem_cgroup_reset,
4587 .read = mem_cgroup_read,
4591 .read_seq_string = mem_control_stat_show,
4594 .name = "force_empty",
4595 .trigger = mem_cgroup_force_empty_write,
4598 .name = "use_hierarchy",
4599 .write_u64 = mem_cgroup_hierarchy_write,
4600 .read_u64 = mem_cgroup_hierarchy_read,
4603 .name = "swappiness",
4604 .read_u64 = mem_cgroup_swappiness_read,
4605 .write_u64 = mem_cgroup_swappiness_write,
4608 .name = "move_charge_at_immigrate",
4609 .read_u64 = mem_cgroup_move_charge_read,
4610 .write_u64 = mem_cgroup_move_charge_write,
4613 .name = "oom_control",
4614 .read_map = mem_cgroup_oom_control_read,
4615 .write_u64 = mem_cgroup_oom_control_write,
4616 .register_event = mem_cgroup_oom_register_event,
4617 .unregister_event = mem_cgroup_oom_unregister_event,
4618 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4622 .name = "numa_stat",
4623 .read_seq_string = mem_control_numa_stat_show,
4626 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4628 .name = "memsw.usage_in_bytes",
4629 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
4630 .read = mem_cgroup_read,
4631 .register_event = mem_cgroup_usage_register_event,
4632 .unregister_event = mem_cgroup_usage_unregister_event,
4635 .name = "memsw.max_usage_in_bytes",
4636 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
4637 .trigger = mem_cgroup_reset,
4638 .read = mem_cgroup_read,
4641 .name = "memsw.limit_in_bytes",
4642 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
4643 .write_string = mem_cgroup_write,
4644 .read = mem_cgroup_read,
4647 .name = "memsw.failcnt",
4648 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
4649 .trigger = mem_cgroup_reset,
4650 .read = mem_cgroup_read,
4653 { }, /* terminate */
4656 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4658 struct mem_cgroup_per_node *pn;
4659 struct mem_cgroup_per_zone *mz;
4660 int zone, tmp = node;
4662 * This routine is called against possible nodes.
4663 * But it's BUG to call kmalloc() against offline node.
4665 * TODO: this routine can waste much memory for nodes which will
4666 * never be onlined. It's better to use memory hotplug callback
4669 if (!node_state(node, N_NORMAL_MEMORY))
4671 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4675 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4676 mz = &pn->zoneinfo[zone];
4677 lruvec_init(&mz->lruvec, &NODE_DATA(node)->node_zones[zone]);
4678 mz->usage_in_excess = 0;
4679 mz->on_tree = false;
4682 memcg->info.nodeinfo[node] = pn;
4686 static void free_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
4688 kfree(memcg->info.nodeinfo[node]);
4691 static struct mem_cgroup *mem_cgroup_alloc(void)
4693 struct mem_cgroup *memcg;
4694 int size = sizeof(struct mem_cgroup);
4696 /* Can be very big if MAX_NUMNODES is very big */
4697 if (size < PAGE_SIZE)
4698 memcg = kzalloc(size, GFP_KERNEL);
4700 memcg = vzalloc(size);
4705 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4708 spin_lock_init(&memcg->pcp_counter_lock);
4712 if (size < PAGE_SIZE)
4720 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
4721 * but in process context. The work_freeing structure is overlaid
4722 * on the rcu_freeing structure, which itself is overlaid on memsw.
4724 static void free_work(struct work_struct *work)
4726 struct mem_cgroup *memcg;
4727 int size = sizeof(struct mem_cgroup);
4729 memcg = container_of(work, struct mem_cgroup, work_freeing);
4731 * We need to make sure that (at least for now), the jump label
4732 * destruction code runs outside of the cgroup lock. This is because
4733 * get_online_cpus(), which is called from the static_branch update,
4734 * can't be called inside the cgroup_lock. cpusets are the ones
4735 * enforcing this dependency, so if they ever change, we might as well.
4737 * schedule_work() will guarantee this happens. Be careful if you need
4738 * to move this code around, and make sure it is outside
4741 disarm_sock_keys(memcg);
4742 if (size < PAGE_SIZE)
4748 static void free_rcu(struct rcu_head *rcu_head)
4750 struct mem_cgroup *memcg;
4752 memcg = container_of(rcu_head, struct mem_cgroup, rcu_freeing);
4753 INIT_WORK(&memcg->work_freeing, free_work);
4754 schedule_work(&memcg->work_freeing);
4758 * At destroying mem_cgroup, references from swap_cgroup can remain.
4759 * (scanning all at force_empty is too costly...)
4761 * Instead of clearing all references at force_empty, we remember
4762 * the number of reference from swap_cgroup and free mem_cgroup when
4763 * it goes down to 0.
4765 * Removal of cgroup itself succeeds regardless of refs from swap.
4768 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4772 mem_cgroup_remove_from_trees(memcg);
4773 free_css_id(&mem_cgroup_subsys, &memcg->css);
4776 free_mem_cgroup_per_zone_info(memcg, node);
4778 free_percpu(memcg->stat);
4779 call_rcu(&memcg->rcu_freeing, free_rcu);
4782 static void mem_cgroup_get(struct mem_cgroup *memcg)
4784 atomic_inc(&memcg->refcnt);
4787 static void __mem_cgroup_put(struct mem_cgroup *memcg, int count)
4789 if (atomic_sub_and_test(count, &memcg->refcnt)) {
4790 struct mem_cgroup *parent = parent_mem_cgroup(memcg);
4791 __mem_cgroup_free(memcg);
4793 mem_cgroup_put(parent);
4797 static void mem_cgroup_put(struct mem_cgroup *memcg)
4799 __mem_cgroup_put(memcg, 1);
4803 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4805 struct mem_cgroup *parent_mem_cgroup(struct mem_cgroup *memcg)
4807 if (!memcg->res.parent)
4809 return mem_cgroup_from_res_counter(memcg->res.parent, res);
4811 EXPORT_SYMBOL(parent_mem_cgroup);
4813 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
4814 static void __init enable_swap_cgroup(void)
4816 if (!mem_cgroup_disabled() && really_do_swap_account)
4817 do_swap_account = 1;
4820 static void __init enable_swap_cgroup(void)
4825 static int mem_cgroup_soft_limit_tree_init(void)
4827 struct mem_cgroup_tree_per_node *rtpn;
4828 struct mem_cgroup_tree_per_zone *rtpz;
4829 int tmp, node, zone;
4831 for_each_node(node) {
4833 if (!node_state(node, N_NORMAL_MEMORY))
4835 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, tmp);
4839 soft_limit_tree.rb_tree_per_node[node] = rtpn;
4841 for (zone = 0; zone < MAX_NR_ZONES; zone++) {
4842 rtpz = &rtpn->rb_tree_per_zone[zone];
4843 rtpz->rb_root = RB_ROOT;
4844 spin_lock_init(&rtpz->lock);
4850 for_each_node(node) {
4851 if (!soft_limit_tree.rb_tree_per_node[node])
4853 kfree(soft_limit_tree.rb_tree_per_node[node]);
4854 soft_limit_tree.rb_tree_per_node[node] = NULL;
4860 static struct cgroup_subsys_state * __ref
4861 mem_cgroup_create(struct cgroup *cont)
4863 struct mem_cgroup *memcg, *parent;
4864 long error = -ENOMEM;
4867 memcg = mem_cgroup_alloc();
4869 return ERR_PTR(error);
4872 if (alloc_mem_cgroup_per_zone_info(memcg, node))
4876 if (cont->parent == NULL) {
4878 enable_swap_cgroup();
4880 if (mem_cgroup_soft_limit_tree_init())
4882 root_mem_cgroup = memcg;
4883 for_each_possible_cpu(cpu) {
4884 struct memcg_stock_pcp *stock =
4885 &per_cpu(memcg_stock, cpu);
4886 INIT_WORK(&stock->work, drain_local_stock);
4888 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
4890 parent = mem_cgroup_from_cont(cont->parent);
4891 memcg->use_hierarchy = parent->use_hierarchy;
4892 memcg->oom_kill_disable = parent->oom_kill_disable;
4895 if (parent && parent->use_hierarchy) {
4896 res_counter_init(&memcg->res, &parent->res);
4897 res_counter_init(&memcg->memsw, &parent->memsw);
4899 * We increment refcnt of the parent to ensure that we can
4900 * safely access it on res_counter_charge/uncharge.
4901 * This refcnt will be decremented when freeing this
4902 * mem_cgroup(see mem_cgroup_put).
4904 mem_cgroup_get(parent);
4906 res_counter_init(&memcg->res, NULL);
4907 res_counter_init(&memcg->memsw, NULL);
4909 memcg->last_scanned_node = MAX_NUMNODES;
4910 INIT_LIST_HEAD(&memcg->oom_notify);
4913 memcg->swappiness = mem_cgroup_swappiness(parent);
4914 atomic_set(&memcg->refcnt, 1);
4915 memcg->move_charge_at_immigrate = 0;
4916 mutex_init(&memcg->thresholds_lock);
4917 spin_lock_init(&memcg->move_lock);
4919 error = memcg_init_kmem(memcg, &mem_cgroup_subsys);
4922 * We call put now because our (and parent's) refcnts
4923 * are already in place. mem_cgroup_put() will internally
4924 * call __mem_cgroup_free, so return directly
4926 mem_cgroup_put(memcg);
4927 return ERR_PTR(error);
4931 __mem_cgroup_free(memcg);
4932 return ERR_PTR(error);
4935 static int mem_cgroup_pre_destroy(struct cgroup *cont)
4937 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4939 return mem_cgroup_force_empty(memcg, false);
4942 static void mem_cgroup_destroy(struct cgroup *cont)
4944 struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
4946 kmem_cgroup_destroy(memcg);
4948 mem_cgroup_put(memcg);
4952 /* Handlers for move charge at task migration. */
4953 #define PRECHARGE_COUNT_AT_ONCE 256
4954 static int mem_cgroup_do_precharge(unsigned long count)
4957 int batch_count = PRECHARGE_COUNT_AT_ONCE;
4958 struct mem_cgroup *memcg = mc.to;
4960 if (mem_cgroup_is_root(memcg)) {
4961 mc.precharge += count;
4962 /* we don't need css_get for root */
4965 /* try to charge at once */
4967 struct res_counter *dummy;
4969 * "memcg" cannot be under rmdir() because we've already checked
4970 * by cgroup_lock_live_cgroup() that it is not removed and we
4971 * are still under the same cgroup_mutex. So we can postpone
4974 if (res_counter_charge(&memcg->res, PAGE_SIZE * count, &dummy))
4976 if (do_swap_account && res_counter_charge(&memcg->memsw,
4977 PAGE_SIZE * count, &dummy)) {
4978 res_counter_uncharge(&memcg->res, PAGE_SIZE * count);
4981 mc.precharge += count;
4985 /* fall back to one by one charge */
4987 if (signal_pending(current)) {
4991 if (!batch_count--) {
4992 batch_count = PRECHARGE_COUNT_AT_ONCE;
4995 ret = __mem_cgroup_try_charge(NULL,
4996 GFP_KERNEL, 1, &memcg, false);
4998 /* mem_cgroup_clear_mc() will do uncharge later */
5006 * get_mctgt_type - get target type of moving charge
5007 * @vma: the vma the pte to be checked belongs
5008 * @addr: the address corresponding to the pte to be checked
5009 * @ptent: the pte to be checked
5010 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5013 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5014 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5015 * move charge. if @target is not NULL, the page is stored in target->page
5016 * with extra refcnt got(Callers should handle it).
5017 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5018 * target for charge migration. if @target is not NULL, the entry is stored
5021 * Called with pte lock held.
5028 enum mc_target_type {
5034 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5035 unsigned long addr, pte_t ptent)
5037 struct page *page = vm_normal_page(vma, addr, ptent);
5039 if (!page || !page_mapped(page))
5041 if (PageAnon(page)) {
5042 /* we don't move shared anon */
5045 } else if (!move_file())
5046 /* we ignore mapcount for file pages */
5048 if (!get_page_unless_zero(page))
5055 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5056 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5058 struct page *page = NULL;
5059 swp_entry_t ent = pte_to_swp_entry(ptent);
5061 if (!move_anon() || non_swap_entry(ent))
5064 * Because lookup_swap_cache() updates some statistics counter,
5065 * we call find_get_page() with swapper_space directly.
5067 page = find_get_page(&swapper_space, ent.val);
5068 if (do_swap_account)
5069 entry->val = ent.val;
5074 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5075 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5081 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5082 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5084 struct page *page = NULL;
5085 struct address_space *mapping;
5088 if (!vma->vm_file) /* anonymous vma */
5093 mapping = vma->vm_file->f_mapping;
5094 if (pte_none(ptent))
5095 pgoff = linear_page_index(vma, addr);
5096 else /* pte_file(ptent) is true */
5097 pgoff = pte_to_pgoff(ptent);
5099 /* page is moved even if it's not RSS of this task(page-faulted). */
5100 page = find_get_page(mapping, pgoff);
5103 /* shmem/tmpfs may report page out on swap: account for that too. */
5104 if (radix_tree_exceptional_entry(page)) {
5105 swp_entry_t swap = radix_to_swp_entry(page);
5106 if (do_swap_account)
5108 page = find_get_page(&swapper_space, swap.val);
5114 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5115 unsigned long addr, pte_t ptent, union mc_target *target)
5117 struct page *page = NULL;
5118 struct page_cgroup *pc;
5119 enum mc_target_type ret = MC_TARGET_NONE;
5120 swp_entry_t ent = { .val = 0 };
5122 if (pte_present(ptent))
5123 page = mc_handle_present_pte(vma, addr, ptent);
5124 else if (is_swap_pte(ptent))
5125 page = mc_handle_swap_pte(vma, addr, ptent, &ent);
5126 else if (pte_none(ptent) || pte_file(ptent))
5127 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5129 if (!page && !ent.val)
5132 pc = lookup_page_cgroup(page);
5134 * Do only loose check w/o page_cgroup lock.
5135 * mem_cgroup_move_account() checks the pc is valid or not under
5138 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5139 ret = MC_TARGET_PAGE;
5141 target->page = page;
5143 if (!ret || !target)
5146 /* There is a swap entry and a page doesn't exist or isn't charged */
5147 if (ent.val && !ret &&
5148 css_id(&mc.from->css) == lookup_swap_cgroup_id(ent)) {
5149 ret = MC_TARGET_SWAP;
5156 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5158 * We don't consider swapping or file mapped pages because THP does not
5159 * support them for now.
5160 * Caller should make sure that pmd_trans_huge(pmd) is true.
5162 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5163 unsigned long addr, pmd_t pmd, union mc_target *target)
5165 struct page *page = NULL;
5166 struct page_cgroup *pc;
5167 enum mc_target_type ret = MC_TARGET_NONE;
5169 page = pmd_page(pmd);
5170 VM_BUG_ON(!page || !PageHead(page));
5173 pc = lookup_page_cgroup(page);
5174 if (PageCgroupUsed(pc) && pc->mem_cgroup == mc.from) {
5175 ret = MC_TARGET_PAGE;
5178 target->page = page;
5184 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5185 unsigned long addr, pmd_t pmd, union mc_target *target)
5187 return MC_TARGET_NONE;
5191 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5192 unsigned long addr, unsigned long end,
5193 struct mm_walk *walk)
5195 struct vm_area_struct *vma = walk->private;
5199 if (pmd_trans_huge_lock(pmd, vma) == 1) {
5200 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5201 mc.precharge += HPAGE_PMD_NR;
5202 spin_unlock(&vma->vm_mm->page_table_lock);
5206 if (pmd_trans_unstable(pmd))
5208 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5209 for (; addr != end; pte++, addr += PAGE_SIZE)
5210 if (get_mctgt_type(vma, addr, *pte, NULL))
5211 mc.precharge++; /* increment precharge temporarily */
5212 pte_unmap_unlock(pte - 1, ptl);
5218 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5220 unsigned long precharge;
5221 struct vm_area_struct *vma;
5223 down_read(&mm->mmap_sem);
5224 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5225 struct mm_walk mem_cgroup_count_precharge_walk = {
5226 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5230 if (is_vm_hugetlb_page(vma))
5232 walk_page_range(vma->vm_start, vma->vm_end,
5233 &mem_cgroup_count_precharge_walk);
5235 up_read(&mm->mmap_sem);
5237 precharge = mc.precharge;
5243 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5245 unsigned long precharge = mem_cgroup_count_precharge(mm);
5247 VM_BUG_ON(mc.moving_task);
5248 mc.moving_task = current;
5249 return mem_cgroup_do_precharge(precharge);
5252 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5253 static void __mem_cgroup_clear_mc(void)
5255 struct mem_cgroup *from = mc.from;
5256 struct mem_cgroup *to = mc.to;
5258 /* we must uncharge all the leftover precharges from mc.to */
5260 __mem_cgroup_cancel_charge(mc.to, mc.precharge);
5264 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5265 * we must uncharge here.
5267 if (mc.moved_charge) {
5268 __mem_cgroup_cancel_charge(mc.from, mc.moved_charge);
5269 mc.moved_charge = 0;
5271 /* we must fixup refcnts and charges */
5272 if (mc.moved_swap) {
5273 /* uncharge swap account from the old cgroup */
5274 if (!mem_cgroup_is_root(mc.from))
5275 res_counter_uncharge(&mc.from->memsw,
5276 PAGE_SIZE * mc.moved_swap);
5277 __mem_cgroup_put(mc.from, mc.moved_swap);
5279 if (!mem_cgroup_is_root(mc.to)) {
5281 * we charged both to->res and to->memsw, so we should
5284 res_counter_uncharge(&mc.to->res,
5285 PAGE_SIZE * mc.moved_swap);
5287 /* we've already done mem_cgroup_get(mc.to) */
5290 memcg_oom_recover(from);
5291 memcg_oom_recover(to);
5292 wake_up_all(&mc.waitq);
5295 static void mem_cgroup_clear_mc(void)
5297 struct mem_cgroup *from = mc.from;
5300 * we must clear moving_task before waking up waiters at the end of
5303 mc.moving_task = NULL;
5304 __mem_cgroup_clear_mc();
5305 spin_lock(&mc.lock);
5308 spin_unlock(&mc.lock);
5309 mem_cgroup_end_move(from);
5312 static int mem_cgroup_can_attach(struct cgroup *cgroup,
5313 struct cgroup_taskset *tset)
5315 struct task_struct *p = cgroup_taskset_first(tset);
5317 struct mem_cgroup *memcg = mem_cgroup_from_cont(cgroup);
5319 if (memcg->move_charge_at_immigrate) {
5320 struct mm_struct *mm;
5321 struct mem_cgroup *from = mem_cgroup_from_task(p);
5323 VM_BUG_ON(from == memcg);
5325 mm = get_task_mm(p);
5328 /* We move charges only when we move a owner of the mm */
5329 if (mm->owner == p) {
5332 VM_BUG_ON(mc.precharge);
5333 VM_BUG_ON(mc.moved_charge);
5334 VM_BUG_ON(mc.moved_swap);
5335 mem_cgroup_start_move(from);
5336 spin_lock(&mc.lock);
5339 spin_unlock(&mc.lock);
5340 /* We set mc.moving_task later */
5342 ret = mem_cgroup_precharge_mc(mm);
5344 mem_cgroup_clear_mc();
5351 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
5352 struct cgroup_taskset *tset)
5354 mem_cgroup_clear_mc();
5357 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5358 unsigned long addr, unsigned long end,
5359 struct mm_walk *walk)
5362 struct vm_area_struct *vma = walk->private;
5365 enum mc_target_type target_type;
5366 union mc_target target;
5368 struct page_cgroup *pc;
5371 * We don't take compound_lock() here but no race with splitting thp
5373 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5374 * under splitting, which means there's no concurrent thp split,
5375 * - if another thread runs into split_huge_page() just after we
5376 * entered this if-block, the thread must wait for page table lock
5377 * to be unlocked in __split_huge_page_splitting(), where the main
5378 * part of thp split is not executed yet.
5380 if (pmd_trans_huge_lock(pmd, vma) == 1) {
5381 if (mc.precharge < HPAGE_PMD_NR) {
5382 spin_unlock(&vma->vm_mm->page_table_lock);
5385 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5386 if (target_type == MC_TARGET_PAGE) {
5388 if (!isolate_lru_page(page)) {
5389 pc = lookup_page_cgroup(page);
5390 if (!mem_cgroup_move_account(page, HPAGE_PMD_NR,
5391 pc, mc.from, mc.to)) {
5392 mc.precharge -= HPAGE_PMD_NR;
5393 mc.moved_charge += HPAGE_PMD_NR;
5395 putback_lru_page(page);
5399 spin_unlock(&vma->vm_mm->page_table_lock);
5403 if (pmd_trans_unstable(pmd))
5406 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5407 for (; addr != end; addr += PAGE_SIZE) {
5408 pte_t ptent = *(pte++);
5414 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5415 case MC_TARGET_PAGE:
5417 if (isolate_lru_page(page))
5419 pc = lookup_page_cgroup(page);
5420 if (!mem_cgroup_move_account(page, 1, pc,
5423 /* we uncharge from mc.from later. */
5426 putback_lru_page(page);
5427 put: /* get_mctgt_type() gets the page */
5430 case MC_TARGET_SWAP:
5432 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5434 /* we fixup refcnts and charges later. */
5442 pte_unmap_unlock(pte - 1, ptl);
5447 * We have consumed all precharges we got in can_attach().
5448 * We try charge one by one, but don't do any additional
5449 * charges to mc.to if we have failed in charge once in attach()
5452 ret = mem_cgroup_do_precharge(1);
5460 static void mem_cgroup_move_charge(struct mm_struct *mm)
5462 struct vm_area_struct *vma;
5464 lru_add_drain_all();
5466 if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
5468 * Someone who are holding the mmap_sem might be waiting in
5469 * waitq. So we cancel all extra charges, wake up all waiters,
5470 * and retry. Because we cancel precharges, we might not be able
5471 * to move enough charges, but moving charge is a best-effort
5472 * feature anyway, so it wouldn't be a big problem.
5474 __mem_cgroup_clear_mc();
5478 for (vma = mm->mmap; vma; vma = vma->vm_next) {
5480 struct mm_walk mem_cgroup_move_charge_walk = {
5481 .pmd_entry = mem_cgroup_move_charge_pte_range,
5485 if (is_vm_hugetlb_page(vma))
5487 ret = walk_page_range(vma->vm_start, vma->vm_end,
5488 &mem_cgroup_move_charge_walk);
5491 * means we have consumed all precharges and failed in
5492 * doing additional charge. Just abandon here.
5496 up_read(&mm->mmap_sem);
5499 static void mem_cgroup_move_task(struct cgroup *cont,
5500 struct cgroup_taskset *tset)
5502 struct task_struct *p = cgroup_taskset_first(tset);
5503 struct mm_struct *mm = get_task_mm(p);
5507 mem_cgroup_move_charge(mm);
5511 mem_cgroup_clear_mc();
5513 #else /* !CONFIG_MMU */
5514 static int mem_cgroup_can_attach(struct cgroup *cgroup,
5515 struct cgroup_taskset *tset)
5519 static void mem_cgroup_cancel_attach(struct cgroup *cgroup,
5520 struct cgroup_taskset *tset)
5523 static void mem_cgroup_move_task(struct cgroup *cont,
5524 struct cgroup_taskset *tset)
5529 struct cgroup_subsys mem_cgroup_subsys = {
5531 .subsys_id = mem_cgroup_subsys_id,
5532 .create = mem_cgroup_create,
5533 .pre_destroy = mem_cgroup_pre_destroy,
5534 .destroy = mem_cgroup_destroy,
5535 .can_attach = mem_cgroup_can_attach,
5536 .cancel_attach = mem_cgroup_cancel_attach,
5537 .attach = mem_cgroup_move_task,
5538 .base_cftypes = mem_cgroup_files,
5541 .__DEPRECATED_clear_css_refs = true,
5544 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
5545 static int __init enable_swap_account(char *s)
5547 /* consider enabled if no parameter or 1 is given */
5548 if (!strcmp(s, "1"))
5549 really_do_swap_account = 1;
5550 else if (!strcmp(s, "0"))
5551 really_do_swap_account = 0;
5554 __setup("swapaccount=", enable_swap_account);