1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
28 #include <linux/page_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
32 #include <linux/hugetlb.h>
33 #include <linux/pagemap.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/swap_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
62 #include <net/tcp_memcontrol.h>
65 #include <asm/uaccess.h>
67 #include <trace/events/vmscan.h>
69 struct cgroup_subsys memory_cgrp_subsys __read_mostly
;
70 EXPORT_SYMBOL(memory_cgrp_subsys
);
72 #define MEM_CGROUP_RECLAIM_RETRIES 5
73 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
75 #ifdef CONFIG_MEMCG_SWAP
76 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
77 int do_swap_account __read_mostly
;
79 /* for remember boot option*/
80 #ifdef CONFIG_MEMCG_SWAP_ENABLED
81 static int really_do_swap_account __initdata
= 1;
83 static int really_do_swap_account __initdata
;
87 #define do_swap_account 0
91 static const char * const mem_cgroup_stat_names
[] = {
100 enum mem_cgroup_events_index
{
101 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
102 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
103 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
104 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
105 MEM_CGROUP_EVENTS_NSTATS
,
108 static const char * const mem_cgroup_events_names
[] = {
115 static const char * const mem_cgroup_lru_names
[] = {
124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
125 * it will be incremated by the number of pages. This counter is used for
126 * for trigger some periodic events. This is straightforward and better
127 * than using jiffies etc. to handle periodic memcg event.
129 enum mem_cgroup_events_target
{
130 MEM_CGROUP_TARGET_THRESH
,
131 MEM_CGROUP_TARGET_SOFTLIMIT
,
132 MEM_CGROUP_TARGET_NUMAINFO
,
135 #define THRESHOLDS_EVENTS_TARGET 128
136 #define SOFTLIMIT_EVENTS_TARGET 1024
137 #define NUMAINFO_EVENTS_TARGET 1024
139 struct mem_cgroup_stat_cpu
{
140 long count
[MEM_CGROUP_STAT_NSTATS
];
141 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
142 unsigned long nr_page_events
;
143 unsigned long targets
[MEM_CGROUP_NTARGETS
];
146 struct reclaim_iter
{
147 struct mem_cgroup
*position
;
148 /* scan generation, increased every round-trip */
149 unsigned int generation
;
153 * per-zone information in memory controller.
155 struct mem_cgroup_per_zone
{
156 struct lruvec lruvec
;
157 unsigned long lru_size
[NR_LRU_LISTS
];
159 struct reclaim_iter iter
[DEF_PRIORITY
+ 1];
161 struct rb_node tree_node
; /* RB tree node */
162 unsigned long usage_in_excess
;/* Set to the value by which */
163 /* the soft limit is exceeded*/
165 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
166 /* use container_of */
169 struct mem_cgroup_per_node
{
170 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
174 * Cgroups above their limits are maintained in a RB-Tree, independent of
175 * their hierarchy representation
178 struct mem_cgroup_tree_per_zone
{
179 struct rb_root rb_root
;
183 struct mem_cgroup_tree_per_node
{
184 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
187 struct mem_cgroup_tree
{
188 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
191 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
193 struct mem_cgroup_threshold
{
194 struct eventfd_ctx
*eventfd
;
195 unsigned long threshold
;
199 struct mem_cgroup_threshold_ary
{
200 /* An array index points to threshold just below or equal to usage. */
201 int current_threshold
;
202 /* Size of entries[] */
204 /* Array of thresholds */
205 struct mem_cgroup_threshold entries
[0];
208 struct mem_cgroup_thresholds
{
209 /* Primary thresholds array */
210 struct mem_cgroup_threshold_ary
*primary
;
212 * Spare threshold array.
213 * This is needed to make mem_cgroup_unregister_event() "never fail".
214 * It must be able to store at least primary->size - 1 entries.
216 struct mem_cgroup_threshold_ary
*spare
;
220 struct mem_cgroup_eventfd_list
{
221 struct list_head list
;
222 struct eventfd_ctx
*eventfd
;
226 * cgroup_event represents events which userspace want to receive.
228 struct mem_cgroup_event
{
230 * memcg which the event belongs to.
232 struct mem_cgroup
*memcg
;
234 * eventfd to signal userspace about the event.
236 struct eventfd_ctx
*eventfd
;
238 * Each of these stored in a list by the cgroup.
240 struct list_head list
;
242 * register_event() callback will be used to add new userspace
243 * waiter for changes related to this event. Use eventfd_signal()
244 * on eventfd to send notification to userspace.
246 int (*register_event
)(struct mem_cgroup
*memcg
,
247 struct eventfd_ctx
*eventfd
, const char *args
);
249 * unregister_event() callback will be called when userspace closes
250 * the eventfd or on cgroup removing. This callback must be set,
251 * if you want provide notification functionality.
253 void (*unregister_event
)(struct mem_cgroup
*memcg
,
254 struct eventfd_ctx
*eventfd
);
256 * All fields below needed to unregister event when
257 * userspace closes eventfd.
260 wait_queue_head_t
*wqh
;
262 struct work_struct remove
;
265 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
266 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
269 * The memory controller data structure. The memory controller controls both
270 * page cache and RSS per cgroup. We would eventually like to provide
271 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
272 * to help the administrator determine what knobs to tune.
274 * TODO: Add a water mark for the memory controller. Reclaim will begin when
275 * we hit the water mark. May be even add a low water mark, such that
276 * no reclaim occurs from a cgroup at it's low water mark, this is
277 * a feature that will be implemented much later in the future.
280 struct cgroup_subsys_state css
;
282 /* Accounted resources */
283 struct page_counter memory
;
284 struct page_counter memsw
;
285 struct page_counter kmem
;
287 unsigned long soft_limit
;
289 /* vmpressure notifications */
290 struct vmpressure vmpressure
;
292 /* css_online() has been completed */
296 * Should the accounting and control be hierarchical, per subtree?
302 atomic_t oom_wakeups
;
305 /* OOM-Killer disable */
306 int oom_kill_disable
;
308 /* protect arrays of thresholds */
309 struct mutex thresholds_lock
;
311 /* thresholds for memory usage. RCU-protected */
312 struct mem_cgroup_thresholds thresholds
;
314 /* thresholds for mem+swap usage. RCU-protected */
315 struct mem_cgroup_thresholds memsw_thresholds
;
317 /* For oom notifier event fd */
318 struct list_head oom_notify
;
321 * Should we move charges of a task when a task is moved into this
322 * mem_cgroup ? And what type of charges should we move ?
324 unsigned long move_charge_at_immigrate
;
326 * set > 0 if pages under this cgroup are moving to other cgroup.
328 atomic_t moving_account
;
329 /* taken only while moving_account > 0 */
330 spinlock_t move_lock
;
334 struct mem_cgroup_stat_cpu __percpu
*stat
;
336 * used when a cpu is offlined or other synchronizations
337 * See mem_cgroup_read_stat().
339 struct mem_cgroup_stat_cpu nocpu_base
;
340 spinlock_t pcp_counter_lock
;
342 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
343 struct cg_proto tcp_mem
;
345 #if defined(CONFIG_MEMCG_KMEM)
346 /* analogous to slab_common's slab_caches list, but per-memcg;
347 * protected by memcg_slab_mutex */
348 struct list_head memcg_slab_caches
;
349 /* Index in the kmem_cache->memcg_params->memcg_caches array */
353 int last_scanned_node
;
355 nodemask_t scan_nodes
;
356 atomic_t numainfo_events
;
357 atomic_t numainfo_updating
;
360 /* List of events which userspace want to receive */
361 struct list_head event_list
;
362 spinlock_t event_list_lock
;
364 struct mem_cgroup_per_node
*nodeinfo
[0];
365 /* WARNING: nodeinfo must be the last member here */
368 #ifdef CONFIG_MEMCG_KMEM
369 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
371 return memcg
->kmemcg_id
>= 0;
375 /* Stuffs for move charges at task migration. */
377 * Types of charges to be moved. "move_charge_at_immitgrate" and
378 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
381 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
382 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
386 /* "mc" and its members are protected by cgroup_mutex */
387 static struct move_charge_struct
{
388 spinlock_t lock
; /* for from, to */
389 struct mem_cgroup
*from
;
390 struct mem_cgroup
*to
;
391 unsigned long immigrate_flags
;
392 unsigned long precharge
;
393 unsigned long moved_charge
;
394 unsigned long moved_swap
;
395 struct task_struct
*moving_task
; /* a task moving charges */
396 wait_queue_head_t waitq
; /* a waitq for other context */
398 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
399 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
402 static bool move_anon(void)
404 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
407 static bool move_file(void)
409 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
413 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
414 * limit reclaim to prevent infinite loops, if they ever occur.
416 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
417 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
420 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
421 MEM_CGROUP_CHARGE_TYPE_ANON
,
422 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
423 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
427 /* for encoding cft->private value on file */
435 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
436 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
437 #define MEMFILE_ATTR(val) ((val) & 0xffff)
438 /* Used for OOM nofiier */
439 #define OOM_CONTROL (0)
442 * The memcg_create_mutex will be held whenever a new cgroup is created.
443 * As a consequence, any change that needs to protect against new child cgroups
444 * appearing has to hold it as well.
446 static DEFINE_MUTEX(memcg_create_mutex
);
448 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
450 return s
? container_of(s
, struct mem_cgroup
, css
) : NULL
;
453 /* Some nice accessors for the vmpressure. */
454 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
457 memcg
= root_mem_cgroup
;
458 return &memcg
->vmpressure
;
461 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
463 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
466 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
468 return (memcg
== root_mem_cgroup
);
472 * We restrict the id in the range of [1, 65535], so it can fit into
475 #define MEM_CGROUP_ID_MAX USHRT_MAX
477 static inline unsigned short mem_cgroup_id(struct mem_cgroup
*memcg
)
479 return memcg
->css
.id
;
482 static inline struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
484 struct cgroup_subsys_state
*css
;
486 css
= css_from_id(id
, &memory_cgrp_subsys
);
487 return mem_cgroup_from_css(css
);
490 /* Writing them here to avoid exposing memcg's inner layout */
491 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
493 void sock_update_memcg(struct sock
*sk
)
495 if (mem_cgroup_sockets_enabled
) {
496 struct mem_cgroup
*memcg
;
497 struct cg_proto
*cg_proto
;
499 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
501 /* Socket cloning can throw us here with sk_cgrp already
502 * filled. It won't however, necessarily happen from
503 * process context. So the test for root memcg given
504 * the current task's memcg won't help us in this case.
506 * Respecting the original socket's memcg is a better
507 * decision in this case.
510 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
511 css_get(&sk
->sk_cgrp
->memcg
->css
);
516 memcg
= mem_cgroup_from_task(current
);
517 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
518 if (!mem_cgroup_is_root(memcg
) &&
519 memcg_proto_active(cg_proto
) &&
520 css_tryget_online(&memcg
->css
)) {
521 sk
->sk_cgrp
= cg_proto
;
526 EXPORT_SYMBOL(sock_update_memcg
);
528 void sock_release_memcg(struct sock
*sk
)
530 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
531 struct mem_cgroup
*memcg
;
532 WARN_ON(!sk
->sk_cgrp
->memcg
);
533 memcg
= sk
->sk_cgrp
->memcg
;
534 css_put(&sk
->sk_cgrp
->memcg
->css
);
538 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
540 if (!memcg
|| mem_cgroup_is_root(memcg
))
543 return &memcg
->tcp_mem
;
545 EXPORT_SYMBOL(tcp_proto_cgroup
);
547 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
549 if (!memcg_proto_activated(&memcg
->tcp_mem
))
551 static_key_slow_dec(&memcg_socket_limit_enabled
);
554 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
559 #ifdef CONFIG_MEMCG_KMEM
561 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
562 * The main reason for not using cgroup id for this:
563 * this works better in sparse environments, where we have a lot of memcgs,
564 * but only a few kmem-limited. Or also, if we have, for instance, 200
565 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
566 * 200 entry array for that.
568 * The current size of the caches array is stored in
569 * memcg_limited_groups_array_size. It will double each time we have to
572 static DEFINE_IDA(kmem_limited_groups
);
573 int memcg_limited_groups_array_size
;
576 * MIN_SIZE is different than 1, because we would like to avoid going through
577 * the alloc/free process all the time. In a small machine, 4 kmem-limited
578 * cgroups is a reasonable guess. In the future, it could be a parameter or
579 * tunable, but that is strictly not necessary.
581 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
582 * this constant directly from cgroup, but it is understandable that this is
583 * better kept as an internal representation in cgroup.c. In any case, the
584 * cgrp_id space is not getting any smaller, and we don't have to necessarily
585 * increase ours as well if it increases.
587 #define MEMCG_CACHES_MIN_SIZE 4
588 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
591 * A lot of the calls to the cache allocation functions are expected to be
592 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
593 * conditional to this static branch, we'll have to allow modules that does
594 * kmem_cache_alloc and the such to see this symbol as well
596 struct static_key memcg_kmem_enabled_key
;
597 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
599 static void memcg_free_cache_id(int id
);
601 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
603 if (memcg_kmem_is_active(memcg
)) {
604 static_key_slow_dec(&memcg_kmem_enabled_key
);
605 memcg_free_cache_id(memcg
->kmemcg_id
);
608 * This check can't live in kmem destruction function,
609 * since the charges will outlive the cgroup
611 WARN_ON(page_counter_read(&memcg
->kmem
));
614 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
617 #endif /* CONFIG_MEMCG_KMEM */
619 static void disarm_static_keys(struct mem_cgroup
*memcg
)
621 disarm_sock_keys(memcg
);
622 disarm_kmem_keys(memcg
);
625 static struct mem_cgroup_per_zone
*
626 mem_cgroup_zone_zoneinfo(struct mem_cgroup
*memcg
, struct zone
*zone
)
628 int nid
= zone_to_nid(zone
);
629 int zid
= zone_idx(zone
);
631 return &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
634 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
639 static struct mem_cgroup_per_zone
*
640 mem_cgroup_page_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
642 int nid
= page_to_nid(page
);
643 int zid
= page_zonenum(page
);
645 return &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
648 static struct mem_cgroup_tree_per_zone
*
649 soft_limit_tree_node_zone(int nid
, int zid
)
651 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
654 static struct mem_cgroup_tree_per_zone
*
655 soft_limit_tree_from_page(struct page
*page
)
657 int nid
= page_to_nid(page
);
658 int zid
= page_zonenum(page
);
660 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
663 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_zone
*mz
,
664 struct mem_cgroup_tree_per_zone
*mctz
,
665 unsigned long new_usage_in_excess
)
667 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
668 struct rb_node
*parent
= NULL
;
669 struct mem_cgroup_per_zone
*mz_node
;
674 mz
->usage_in_excess
= new_usage_in_excess
;
675 if (!mz
->usage_in_excess
)
679 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
681 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
684 * We can't avoid mem cgroups that are over their soft
685 * limit by the same amount
687 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
690 rb_link_node(&mz
->tree_node
, parent
, p
);
691 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
695 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone
*mz
,
696 struct mem_cgroup_tree_per_zone
*mctz
)
700 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
704 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_zone
*mz
,
705 struct mem_cgroup_tree_per_zone
*mctz
)
709 spin_lock_irqsave(&mctz
->lock
, flags
);
710 __mem_cgroup_remove_exceeded(mz
, mctz
);
711 spin_unlock_irqrestore(&mctz
->lock
, flags
);
714 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
716 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
717 unsigned long soft_limit
= ACCESS_ONCE(memcg
->soft_limit
);
718 unsigned long excess
= 0;
720 if (nr_pages
> soft_limit
)
721 excess
= nr_pages
- soft_limit
;
726 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
728 unsigned long excess
;
729 struct mem_cgroup_per_zone
*mz
;
730 struct mem_cgroup_tree_per_zone
*mctz
;
732 mctz
= soft_limit_tree_from_page(page
);
734 * Necessary to update all ancestors when hierarchy is used.
735 * because their event counter is not touched.
737 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
738 mz
= mem_cgroup_page_zoneinfo(memcg
, page
);
739 excess
= soft_limit_excess(memcg
);
741 * We have to update the tree if mz is on RB-tree or
742 * mem is over its softlimit.
744 if (excess
|| mz
->on_tree
) {
747 spin_lock_irqsave(&mctz
->lock
, flags
);
748 /* if on-tree, remove it */
750 __mem_cgroup_remove_exceeded(mz
, mctz
);
752 * Insert again. mz->usage_in_excess will be updated.
753 * If excess is 0, no tree ops.
755 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
756 spin_unlock_irqrestore(&mctz
->lock
, flags
);
761 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
763 struct mem_cgroup_tree_per_zone
*mctz
;
764 struct mem_cgroup_per_zone
*mz
;
768 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
769 mz
= &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
770 mctz
= soft_limit_tree_node_zone(nid
, zid
);
771 mem_cgroup_remove_exceeded(mz
, mctz
);
776 static struct mem_cgroup_per_zone
*
777 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
779 struct rb_node
*rightmost
= NULL
;
780 struct mem_cgroup_per_zone
*mz
;
784 rightmost
= rb_last(&mctz
->rb_root
);
786 goto done
; /* Nothing to reclaim from */
788 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
790 * Remove the node now but someone else can add it back,
791 * we will to add it back at the end of reclaim to its correct
792 * position in the tree.
794 __mem_cgroup_remove_exceeded(mz
, mctz
);
795 if (!soft_limit_excess(mz
->memcg
) ||
796 !css_tryget_online(&mz
->memcg
->css
))
802 static struct mem_cgroup_per_zone
*
803 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
805 struct mem_cgroup_per_zone
*mz
;
807 spin_lock_irq(&mctz
->lock
);
808 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
809 spin_unlock_irq(&mctz
->lock
);
814 * Implementation Note: reading percpu statistics for memcg.
816 * Both of vmstat[] and percpu_counter has threshold and do periodic
817 * synchronization to implement "quick" read. There are trade-off between
818 * reading cost and precision of value. Then, we may have a chance to implement
819 * a periodic synchronizion of counter in memcg's counter.
821 * But this _read() function is used for user interface now. The user accounts
822 * memory usage by memory cgroup and he _always_ requires exact value because
823 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
824 * have to visit all online cpus and make sum. So, for now, unnecessary
825 * synchronization is not implemented. (just implemented for cpu hotplug)
827 * If there are kernel internal actions which can make use of some not-exact
828 * value, and reading all cpu value can be performance bottleneck in some
829 * common workload, threashold and synchonization as vmstat[] should be
832 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
833 enum mem_cgroup_stat_index idx
)
839 for_each_online_cpu(cpu
)
840 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
841 #ifdef CONFIG_HOTPLUG_CPU
842 spin_lock(&memcg
->pcp_counter_lock
);
843 val
+= memcg
->nocpu_base
.count
[idx
];
844 spin_unlock(&memcg
->pcp_counter_lock
);
850 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
851 enum mem_cgroup_events_index idx
)
853 unsigned long val
= 0;
857 for_each_online_cpu(cpu
)
858 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
859 #ifdef CONFIG_HOTPLUG_CPU
860 spin_lock(&memcg
->pcp_counter_lock
);
861 val
+= memcg
->nocpu_base
.events
[idx
];
862 spin_unlock(&memcg
->pcp_counter_lock
);
868 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
873 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
874 * counted as CACHE even if it's on ANON LRU.
877 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
880 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
883 if (PageTransHuge(page
))
884 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
887 /* pagein of a big page is an event. So, ignore page size */
889 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
891 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
892 nr_pages
= -nr_pages
; /* for event */
895 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
898 unsigned long mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
900 struct mem_cgroup_per_zone
*mz
;
902 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
903 return mz
->lru_size
[lru
];
906 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
908 unsigned int lru_mask
)
910 unsigned long nr
= 0;
913 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
915 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
916 struct mem_cgroup_per_zone
*mz
;
920 if (!(BIT(lru
) & lru_mask
))
922 mz
= &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
923 nr
+= mz
->lru_size
[lru
];
929 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
930 unsigned int lru_mask
)
932 unsigned long nr
= 0;
935 for_each_node_state(nid
, N_MEMORY
)
936 nr
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
940 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
941 enum mem_cgroup_events_target target
)
943 unsigned long val
, next
;
945 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
946 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
947 /* from time_after() in jiffies.h */
948 if ((long)next
- (long)val
< 0) {
950 case MEM_CGROUP_TARGET_THRESH
:
951 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
953 case MEM_CGROUP_TARGET_SOFTLIMIT
:
954 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
956 case MEM_CGROUP_TARGET_NUMAINFO
:
957 next
= val
+ NUMAINFO_EVENTS_TARGET
;
962 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
969 * Check events in order.
972 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
974 /* threshold event is triggered in finer grain than soft limit */
975 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
976 MEM_CGROUP_TARGET_THRESH
))) {
978 bool do_numainfo __maybe_unused
;
980 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
981 MEM_CGROUP_TARGET_SOFTLIMIT
);
983 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
984 MEM_CGROUP_TARGET_NUMAINFO
);
986 mem_cgroup_threshold(memcg
);
987 if (unlikely(do_softlimit
))
988 mem_cgroup_update_tree(memcg
, page
);
990 if (unlikely(do_numainfo
))
991 atomic_inc(&memcg
->numainfo_events
);
996 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
999 * mm_update_next_owner() may clear mm->owner to NULL
1000 * if it races with swapoff, page migration, etc.
1001 * So this can be called with p == NULL.
1006 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
1009 static struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1011 struct mem_cgroup
*memcg
= NULL
;
1016 * Page cache insertions can happen withou an
1017 * actual mm context, e.g. during disk probing
1018 * on boot, loopback IO, acct() writes etc.
1021 memcg
= root_mem_cgroup
;
1023 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1024 if (unlikely(!memcg
))
1025 memcg
= root_mem_cgroup
;
1027 } while (!css_tryget_online(&memcg
->css
));
1033 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1034 * @root: hierarchy root
1035 * @prev: previously returned memcg, NULL on first invocation
1036 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1038 * Returns references to children of the hierarchy below @root, or
1039 * @root itself, or %NULL after a full round-trip.
1041 * Caller must pass the return value in @prev on subsequent
1042 * invocations for reference counting, or use mem_cgroup_iter_break()
1043 * to cancel a hierarchy walk before the round-trip is complete.
1045 * Reclaimers can specify a zone and a priority level in @reclaim to
1046 * divide up the memcgs in the hierarchy among all concurrent
1047 * reclaimers operating on the same zone and priority.
1049 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1050 struct mem_cgroup
*prev
,
1051 struct mem_cgroup_reclaim_cookie
*reclaim
)
1053 struct reclaim_iter
*uninitialized_var(iter
);
1054 struct cgroup_subsys_state
*css
= NULL
;
1055 struct mem_cgroup
*memcg
= NULL
;
1056 struct mem_cgroup
*pos
= NULL
;
1058 if (mem_cgroup_disabled())
1062 root
= root_mem_cgroup
;
1064 if (prev
&& !reclaim
)
1067 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1076 struct mem_cgroup_per_zone
*mz
;
1078 mz
= mem_cgroup_zone_zoneinfo(root
, reclaim
->zone
);
1079 iter
= &mz
->iter
[reclaim
->priority
];
1081 if (prev
&& reclaim
->generation
!= iter
->generation
)
1085 pos
= ACCESS_ONCE(iter
->position
);
1087 * A racing update may change the position and
1088 * put the last reference, hence css_tryget(),
1089 * or retry to see the updated position.
1091 } while (pos
&& !css_tryget(&pos
->css
));
1098 css
= css_next_descendant_pre(css
, &root
->css
);
1101 * Reclaimers share the hierarchy walk, and a
1102 * new one might jump in right at the end of
1103 * the hierarchy - make sure they see at least
1104 * one group and restart from the beginning.
1112 * Verify the css and acquire a reference. The root
1113 * is provided by the caller, so we know it's alive
1114 * and kicking, and don't take an extra reference.
1116 memcg
= mem_cgroup_from_css(css
);
1118 if (css
== &root
->css
)
1121 if (css_tryget(css
)) {
1123 * Make sure the memcg is initialized:
1124 * mem_cgroup_css_online() orders the the
1125 * initialization against setting the flag.
1127 if (smp_load_acquire(&memcg
->initialized
))
1137 if (cmpxchg(&iter
->position
, pos
, memcg
) == pos
) {
1139 css_get(&memcg
->css
);
1145 * pairs with css_tryget when dereferencing iter->position
1154 reclaim
->generation
= iter
->generation
;
1160 if (prev
&& prev
!= root
)
1161 css_put(&prev
->css
);
1167 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1168 * @root: hierarchy root
1169 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1171 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1172 struct mem_cgroup
*prev
)
1175 root
= root_mem_cgroup
;
1176 if (prev
&& prev
!= root
)
1177 css_put(&prev
->css
);
1181 * Iteration constructs for visiting all cgroups (under a tree). If
1182 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1183 * be used for reference counting.
1185 #define for_each_mem_cgroup_tree(iter, root) \
1186 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1188 iter = mem_cgroup_iter(root, iter, NULL))
1190 #define for_each_mem_cgroup(iter) \
1191 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1193 iter = mem_cgroup_iter(NULL, iter, NULL))
1195 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1197 struct mem_cgroup
*memcg
;
1200 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1201 if (unlikely(!memcg
))
1206 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1209 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1217 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1220 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1221 * @zone: zone of the wanted lruvec
1222 * @memcg: memcg of the wanted lruvec
1224 * Returns the lru list vector holding pages for the given @zone and
1225 * @mem. This can be the global zone lruvec, if the memory controller
1228 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1229 struct mem_cgroup
*memcg
)
1231 struct mem_cgroup_per_zone
*mz
;
1232 struct lruvec
*lruvec
;
1234 if (mem_cgroup_disabled()) {
1235 lruvec
= &zone
->lruvec
;
1239 mz
= mem_cgroup_zone_zoneinfo(memcg
, zone
);
1240 lruvec
= &mz
->lruvec
;
1243 * Since a node can be onlined after the mem_cgroup was created,
1244 * we have to be prepared to initialize lruvec->zone here;
1245 * and if offlined then reonlined, we need to reinitialize it.
1247 if (unlikely(lruvec
->zone
!= zone
))
1248 lruvec
->zone
= zone
;
1253 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1255 * @zone: zone of the page
1257 * This function is only safe when following the LRU page isolation
1258 * and putback protocol: the LRU lock must be held, and the page must
1259 * either be PageLRU() or the caller must have isolated/allocated it.
1261 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1263 struct mem_cgroup_per_zone
*mz
;
1264 struct mem_cgroup
*memcg
;
1265 struct lruvec
*lruvec
;
1267 if (mem_cgroup_disabled()) {
1268 lruvec
= &zone
->lruvec
;
1272 memcg
= page
->mem_cgroup
;
1274 * Swapcache readahead pages are added to the LRU - and
1275 * possibly migrated - before they are charged.
1278 memcg
= root_mem_cgroup
;
1280 mz
= mem_cgroup_page_zoneinfo(memcg
, page
);
1281 lruvec
= &mz
->lruvec
;
1284 * Since a node can be onlined after the mem_cgroup was created,
1285 * we have to be prepared to initialize lruvec->zone here;
1286 * and if offlined then reonlined, we need to reinitialize it.
1288 if (unlikely(lruvec
->zone
!= zone
))
1289 lruvec
->zone
= zone
;
1294 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1295 * @lruvec: mem_cgroup per zone lru vector
1296 * @lru: index of lru list the page is sitting on
1297 * @nr_pages: positive when adding or negative when removing
1299 * This function must be called when a page is added to or removed from an
1302 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1305 struct mem_cgroup_per_zone
*mz
;
1306 unsigned long *lru_size
;
1308 if (mem_cgroup_disabled())
1311 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1312 lru_size
= mz
->lru_size
+ lru
;
1313 *lru_size
+= nr_pages
;
1314 VM_BUG_ON((long)(*lru_size
) < 0);
1317 bool mem_cgroup_is_descendant(struct mem_cgroup
*memcg
, struct mem_cgroup
*root
)
1321 if (!root
->use_hierarchy
)
1323 return cgroup_is_descendant(memcg
->css
.cgroup
, root
->css
.cgroup
);
1326 bool task_in_mem_cgroup(struct task_struct
*task
, struct mem_cgroup
*memcg
)
1328 struct mem_cgroup
*task_memcg
;
1329 struct task_struct
*p
;
1332 p
= find_lock_task_mm(task
);
1334 task_memcg
= get_mem_cgroup_from_mm(p
->mm
);
1338 * All threads may have already detached their mm's, but the oom
1339 * killer still needs to detect if they have already been oom
1340 * killed to prevent needlessly killing additional tasks.
1343 task_memcg
= mem_cgroup_from_task(task
);
1344 css_get(&task_memcg
->css
);
1347 ret
= mem_cgroup_is_descendant(task_memcg
, memcg
);
1348 css_put(&task_memcg
->css
);
1352 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1354 unsigned long inactive_ratio
;
1355 unsigned long inactive
;
1356 unsigned long active
;
1359 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1360 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1362 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1364 inactive_ratio
= int_sqrt(10 * gb
);
1368 return inactive
* inactive_ratio
< active
;
1371 #define mem_cgroup_from_counter(counter, member) \
1372 container_of(counter, struct mem_cgroup, member)
1375 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1376 * @memcg: the memory cgroup
1378 * Returns the maximum amount of memory @mem can be charged with, in
1381 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1383 unsigned long margin
= 0;
1384 unsigned long count
;
1385 unsigned long limit
;
1387 count
= page_counter_read(&memcg
->memory
);
1388 limit
= ACCESS_ONCE(memcg
->memory
.limit
);
1390 margin
= limit
- count
;
1392 if (do_swap_account
) {
1393 count
= page_counter_read(&memcg
->memsw
);
1394 limit
= ACCESS_ONCE(memcg
->memsw
.limit
);
1396 margin
= min(margin
, limit
- count
);
1402 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1405 if (mem_cgroup_disabled() || !memcg
->css
.parent
)
1406 return vm_swappiness
;
1408 return memcg
->swappiness
;
1412 * A routine for checking "mem" is under move_account() or not.
1414 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1415 * moving cgroups. This is for waiting at high-memory pressure
1418 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1420 struct mem_cgroup
*from
;
1421 struct mem_cgroup
*to
;
1424 * Unlike task_move routines, we access mc.to, mc.from not under
1425 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1427 spin_lock(&mc
.lock
);
1433 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1434 mem_cgroup_is_descendant(to
, memcg
);
1436 spin_unlock(&mc
.lock
);
1440 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1442 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1443 if (mem_cgroup_under_move(memcg
)) {
1445 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1446 /* moving charge context might have finished. */
1449 finish_wait(&mc
.waitq
, &wait
);
1456 #define K(x) ((x) << (PAGE_SHIFT-10))
1458 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1459 * @memcg: The memory cgroup that went over limit
1460 * @p: Task that is going to be killed
1462 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1465 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1467 /* oom_info_lock ensures that parallel ooms do not interleave */
1468 static DEFINE_MUTEX(oom_info_lock
);
1469 struct mem_cgroup
*iter
;
1475 mutex_lock(&oom_info_lock
);
1478 pr_info("Task in ");
1479 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1480 pr_info(" killed as a result of limit of ");
1481 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1486 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1487 K((u64
)page_counter_read(&memcg
->memory
)),
1488 K((u64
)memcg
->memory
.limit
), memcg
->memory
.failcnt
);
1489 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1490 K((u64
)page_counter_read(&memcg
->memsw
)),
1491 K((u64
)memcg
->memsw
.limit
), memcg
->memsw
.failcnt
);
1492 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1493 K((u64
)page_counter_read(&memcg
->kmem
)),
1494 K((u64
)memcg
->kmem
.limit
), memcg
->kmem
.failcnt
);
1496 for_each_mem_cgroup_tree(iter
, memcg
) {
1497 pr_info("Memory cgroup stats for ");
1498 pr_cont_cgroup_path(iter
->css
.cgroup
);
1501 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1502 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1504 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1505 K(mem_cgroup_read_stat(iter
, i
)));
1508 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1509 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1510 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1514 mutex_unlock(&oom_info_lock
);
1518 * This function returns the number of memcg under hierarchy tree. Returns
1519 * 1(self count) if no children.
1521 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1524 struct mem_cgroup
*iter
;
1526 for_each_mem_cgroup_tree(iter
, memcg
)
1532 * Return the memory (and swap, if configured) limit for a memcg.
1534 static unsigned long mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1536 unsigned long limit
;
1538 limit
= memcg
->memory
.limit
;
1539 if (mem_cgroup_swappiness(memcg
)) {
1540 unsigned long memsw_limit
;
1542 memsw_limit
= memcg
->memsw
.limit
;
1543 limit
= min(limit
+ total_swap_pages
, memsw_limit
);
1548 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1551 struct mem_cgroup
*iter
;
1552 unsigned long chosen_points
= 0;
1553 unsigned long totalpages
;
1554 unsigned int points
= 0;
1555 struct task_struct
*chosen
= NULL
;
1558 * If current has a pending SIGKILL or is exiting, then automatically
1559 * select it. The goal is to allow it to allocate so that it may
1560 * quickly exit and free its memory.
1562 if (fatal_signal_pending(current
) || current
->flags
& PF_EXITING
) {
1563 set_thread_flag(TIF_MEMDIE
);
1567 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1568 totalpages
= mem_cgroup_get_limit(memcg
) ? : 1;
1569 for_each_mem_cgroup_tree(iter
, memcg
) {
1570 struct css_task_iter it
;
1571 struct task_struct
*task
;
1573 css_task_iter_start(&iter
->css
, &it
);
1574 while ((task
= css_task_iter_next(&it
))) {
1575 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1577 case OOM_SCAN_SELECT
:
1579 put_task_struct(chosen
);
1581 chosen_points
= ULONG_MAX
;
1582 get_task_struct(chosen
);
1584 case OOM_SCAN_CONTINUE
:
1586 case OOM_SCAN_ABORT
:
1587 css_task_iter_end(&it
);
1588 mem_cgroup_iter_break(memcg
, iter
);
1590 put_task_struct(chosen
);
1595 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1596 if (!points
|| points
< chosen_points
)
1598 /* Prefer thread group leaders for display purposes */
1599 if (points
== chosen_points
&&
1600 thread_group_leader(chosen
))
1604 put_task_struct(chosen
);
1606 chosen_points
= points
;
1607 get_task_struct(chosen
);
1609 css_task_iter_end(&it
);
1614 points
= chosen_points
* 1000 / totalpages
;
1615 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1616 NULL
, "Memory cgroup out of memory");
1620 * test_mem_cgroup_node_reclaimable
1621 * @memcg: the target memcg
1622 * @nid: the node ID to be checked.
1623 * @noswap : specify true here if the user wants flle only information.
1625 * This function returns whether the specified memcg contains any
1626 * reclaimable pages on a node. Returns true if there are any reclaimable
1627 * pages in the node.
1629 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1630 int nid
, bool noswap
)
1632 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1634 if (noswap
|| !total_swap_pages
)
1636 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1641 #if MAX_NUMNODES > 1
1644 * Always updating the nodemask is not very good - even if we have an empty
1645 * list or the wrong list here, we can start from some node and traverse all
1646 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1649 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1653 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1654 * pagein/pageout changes since the last update.
1656 if (!atomic_read(&memcg
->numainfo_events
))
1658 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1661 /* make a nodemask where this memcg uses memory from */
1662 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1664 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1666 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1667 node_clear(nid
, memcg
->scan_nodes
);
1670 atomic_set(&memcg
->numainfo_events
, 0);
1671 atomic_set(&memcg
->numainfo_updating
, 0);
1675 * Selecting a node where we start reclaim from. Because what we need is just
1676 * reducing usage counter, start from anywhere is O,K. Considering
1677 * memory reclaim from current node, there are pros. and cons.
1679 * Freeing memory from current node means freeing memory from a node which
1680 * we'll use or we've used. So, it may make LRU bad. And if several threads
1681 * hit limits, it will see a contention on a node. But freeing from remote
1682 * node means more costs for memory reclaim because of memory latency.
1684 * Now, we use round-robin. Better algorithm is welcomed.
1686 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1690 mem_cgroup_may_update_nodemask(memcg
);
1691 node
= memcg
->last_scanned_node
;
1693 node
= next_node(node
, memcg
->scan_nodes
);
1694 if (node
== MAX_NUMNODES
)
1695 node
= first_node(memcg
->scan_nodes
);
1697 * We call this when we hit limit, not when pages are added to LRU.
1698 * No LRU may hold pages because all pages are UNEVICTABLE or
1699 * memcg is too small and all pages are not on LRU. In that case,
1700 * we use curret node.
1702 if (unlikely(node
== MAX_NUMNODES
))
1703 node
= numa_node_id();
1705 memcg
->last_scanned_node
= node
;
1709 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1715 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1718 unsigned long *total_scanned
)
1720 struct mem_cgroup
*victim
= NULL
;
1723 unsigned long excess
;
1724 unsigned long nr_scanned
;
1725 struct mem_cgroup_reclaim_cookie reclaim
= {
1730 excess
= soft_limit_excess(root_memcg
);
1733 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1738 * If we have not been able to reclaim
1739 * anything, it might because there are
1740 * no reclaimable pages under this hierarchy
1745 * We want to do more targeted reclaim.
1746 * excess >> 2 is not to excessive so as to
1747 * reclaim too much, nor too less that we keep
1748 * coming back to reclaim from this cgroup
1750 if (total
>= (excess
>> 2) ||
1751 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1756 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
1758 *total_scanned
+= nr_scanned
;
1759 if (!soft_limit_excess(root_memcg
))
1762 mem_cgroup_iter_break(root_memcg
, victim
);
1766 #ifdef CONFIG_LOCKDEP
1767 static struct lockdep_map memcg_oom_lock_dep_map
= {
1768 .name
= "memcg_oom_lock",
1772 static DEFINE_SPINLOCK(memcg_oom_lock
);
1775 * Check OOM-Killer is already running under our hierarchy.
1776 * If someone is running, return false.
1778 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1780 struct mem_cgroup
*iter
, *failed
= NULL
;
1782 spin_lock(&memcg_oom_lock
);
1784 for_each_mem_cgroup_tree(iter
, memcg
) {
1785 if (iter
->oom_lock
) {
1787 * this subtree of our hierarchy is already locked
1788 * so we cannot give a lock.
1791 mem_cgroup_iter_break(memcg
, iter
);
1794 iter
->oom_lock
= true;
1799 * OK, we failed to lock the whole subtree so we have
1800 * to clean up what we set up to the failing subtree
1802 for_each_mem_cgroup_tree(iter
, memcg
) {
1803 if (iter
== failed
) {
1804 mem_cgroup_iter_break(memcg
, iter
);
1807 iter
->oom_lock
= false;
1810 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1812 spin_unlock(&memcg_oom_lock
);
1817 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1819 struct mem_cgroup
*iter
;
1821 spin_lock(&memcg_oom_lock
);
1822 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
1823 for_each_mem_cgroup_tree(iter
, memcg
)
1824 iter
->oom_lock
= false;
1825 spin_unlock(&memcg_oom_lock
);
1828 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1830 struct mem_cgroup
*iter
;
1832 for_each_mem_cgroup_tree(iter
, memcg
)
1833 atomic_inc(&iter
->under_oom
);
1836 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1838 struct mem_cgroup
*iter
;
1841 * When a new child is created while the hierarchy is under oom,
1842 * mem_cgroup_oom_lock() may not be called. We have to use
1843 * atomic_add_unless() here.
1845 for_each_mem_cgroup_tree(iter
, memcg
)
1846 atomic_add_unless(&iter
->under_oom
, -1, 0);
1849 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1851 struct oom_wait_info
{
1852 struct mem_cgroup
*memcg
;
1856 static int memcg_oom_wake_function(wait_queue_t
*wait
,
1857 unsigned mode
, int sync
, void *arg
)
1859 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1860 struct mem_cgroup
*oom_wait_memcg
;
1861 struct oom_wait_info
*oom_wait_info
;
1863 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1864 oom_wait_memcg
= oom_wait_info
->memcg
;
1866 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1867 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1869 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1872 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
1874 atomic_inc(&memcg
->oom_wakeups
);
1875 /* for filtering, pass "memcg" as argument. */
1876 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1879 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1881 if (memcg
&& atomic_read(&memcg
->under_oom
))
1882 memcg_wakeup_oom(memcg
);
1885 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1887 if (!current
->memcg_oom
.may_oom
)
1890 * We are in the middle of the charge context here, so we
1891 * don't want to block when potentially sitting on a callstack
1892 * that holds all kinds of filesystem and mm locks.
1894 * Also, the caller may handle a failed allocation gracefully
1895 * (like optional page cache readahead) and so an OOM killer
1896 * invocation might not even be necessary.
1898 * That's why we don't do anything here except remember the
1899 * OOM context and then deal with it at the end of the page
1900 * fault when the stack is unwound, the locks are released,
1901 * and when we know whether the fault was overall successful.
1903 css_get(&memcg
->css
);
1904 current
->memcg_oom
.memcg
= memcg
;
1905 current
->memcg_oom
.gfp_mask
= mask
;
1906 current
->memcg_oom
.order
= order
;
1910 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1911 * @handle: actually kill/wait or just clean up the OOM state
1913 * This has to be called at the end of a page fault if the memcg OOM
1914 * handler was enabled.
1916 * Memcg supports userspace OOM handling where failed allocations must
1917 * sleep on a waitqueue until the userspace task resolves the
1918 * situation. Sleeping directly in the charge context with all kinds
1919 * of locks held is not a good idea, instead we remember an OOM state
1920 * in the task and mem_cgroup_oom_synchronize() has to be called at
1921 * the end of the page fault to complete the OOM handling.
1923 * Returns %true if an ongoing memcg OOM situation was detected and
1924 * completed, %false otherwise.
1926 bool mem_cgroup_oom_synchronize(bool handle
)
1928 struct mem_cgroup
*memcg
= current
->memcg_oom
.memcg
;
1929 struct oom_wait_info owait
;
1932 /* OOM is global, do not handle */
1939 owait
.memcg
= memcg
;
1940 owait
.wait
.flags
= 0;
1941 owait
.wait
.func
= memcg_oom_wake_function
;
1942 owait
.wait
.private = current
;
1943 INIT_LIST_HEAD(&owait
.wait
.task_list
);
1945 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1946 mem_cgroup_mark_under_oom(memcg
);
1948 locked
= mem_cgroup_oom_trylock(memcg
);
1951 mem_cgroup_oom_notify(memcg
);
1953 if (locked
&& !memcg
->oom_kill_disable
) {
1954 mem_cgroup_unmark_under_oom(memcg
);
1955 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1956 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom
.gfp_mask
,
1957 current
->memcg_oom
.order
);
1960 mem_cgroup_unmark_under_oom(memcg
);
1961 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1965 mem_cgroup_oom_unlock(memcg
);
1967 * There is no guarantee that an OOM-lock contender
1968 * sees the wakeups triggered by the OOM kill
1969 * uncharges. Wake any sleepers explicitely.
1971 memcg_oom_recover(memcg
);
1974 current
->memcg_oom
.memcg
= NULL
;
1975 css_put(&memcg
->css
);
1980 * mem_cgroup_begin_page_stat - begin a page state statistics transaction
1981 * @page: page that is going to change accounted state
1982 * @locked: &memcg->move_lock slowpath was taken
1983 * @flags: IRQ-state flags for &memcg->move_lock
1985 * This function must mark the beginning of an accounted page state
1986 * change to prevent double accounting when the page is concurrently
1987 * being moved to another memcg:
1989 * memcg = mem_cgroup_begin_page_stat(page, &locked, &flags);
1990 * if (TestClearPageState(page))
1991 * mem_cgroup_update_page_stat(memcg, state, -1);
1992 * mem_cgroup_end_page_stat(memcg, locked, flags);
1994 * The RCU lock is held throughout the transaction. The fast path can
1995 * get away without acquiring the memcg->move_lock (@locked is false)
1996 * because page moving starts with an RCU grace period.
1998 * The RCU lock also protects the memcg from being freed when the page
1999 * state that is going to change is the only thing preventing the page
2000 * from being uncharged. E.g. end-writeback clearing PageWriteback(),
2001 * which allows migration to go ahead and uncharge the page before the
2002 * account transaction might be complete.
2004 struct mem_cgroup
*mem_cgroup_begin_page_stat(struct page
*page
,
2006 unsigned long *flags
)
2008 struct mem_cgroup
*memcg
;
2012 if (mem_cgroup_disabled())
2015 memcg
= page
->mem_cgroup
;
2016 if (unlikely(!memcg
))
2020 if (atomic_read(&memcg
->moving_account
) <= 0)
2023 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
2024 if (memcg
!= page
->mem_cgroup
) {
2025 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
2034 * mem_cgroup_end_page_stat - finish a page state statistics transaction
2035 * @memcg: the memcg that was accounted against
2036 * @locked: value received from mem_cgroup_begin_page_stat()
2037 * @flags: value received from mem_cgroup_begin_page_stat()
2039 void mem_cgroup_end_page_stat(struct mem_cgroup
*memcg
, bool *locked
,
2040 unsigned long *flags
)
2042 if (memcg
&& *locked
)
2043 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
2049 * mem_cgroup_update_page_stat - update page state statistics
2050 * @memcg: memcg to account against
2051 * @idx: page state item to account
2052 * @val: number of pages (positive or negative)
2054 * See mem_cgroup_begin_page_stat() for locking requirements.
2056 void mem_cgroup_update_page_stat(struct mem_cgroup
*memcg
,
2057 enum mem_cgroup_stat_index idx
, int val
)
2059 VM_BUG_ON(!rcu_read_lock_held());
2062 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2066 * size of first charge trial. "32" comes from vmscan.c's magic value.
2067 * TODO: maybe necessary to use big numbers in big irons.
2069 #define CHARGE_BATCH 32U
2070 struct memcg_stock_pcp
{
2071 struct mem_cgroup
*cached
; /* this never be root cgroup */
2072 unsigned int nr_pages
;
2073 struct work_struct work
;
2074 unsigned long flags
;
2075 #define FLUSHING_CACHED_CHARGE 0
2077 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2078 static DEFINE_MUTEX(percpu_charge_mutex
);
2081 * consume_stock: Try to consume stocked charge on this cpu.
2082 * @memcg: memcg to consume from.
2083 * @nr_pages: how many pages to charge.
2085 * The charges will only happen if @memcg matches the current cpu's memcg
2086 * stock, and at least @nr_pages are available in that stock. Failure to
2087 * service an allocation will refill the stock.
2089 * returns true if successful, false otherwise.
2091 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2093 struct memcg_stock_pcp
*stock
;
2096 if (nr_pages
> CHARGE_BATCH
)
2099 stock
= &get_cpu_var(memcg_stock
);
2100 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
2101 stock
->nr_pages
-= nr_pages
;
2104 put_cpu_var(memcg_stock
);
2109 * Returns stocks cached in percpu and reset cached information.
2111 static void drain_stock(struct memcg_stock_pcp
*stock
)
2113 struct mem_cgroup
*old
= stock
->cached
;
2115 if (stock
->nr_pages
) {
2116 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
2117 if (do_swap_account
)
2118 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
2119 css_put_many(&old
->css
, stock
->nr_pages
);
2120 stock
->nr_pages
= 0;
2122 stock
->cached
= NULL
;
2126 * This must be called under preempt disabled or must be called by
2127 * a thread which is pinned to local cpu.
2129 static void drain_local_stock(struct work_struct
*dummy
)
2131 struct memcg_stock_pcp
*stock
= this_cpu_ptr(&memcg_stock
);
2133 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2136 static void __init
memcg_stock_init(void)
2140 for_each_possible_cpu(cpu
) {
2141 struct memcg_stock_pcp
*stock
=
2142 &per_cpu(memcg_stock
, cpu
);
2143 INIT_WORK(&stock
->work
, drain_local_stock
);
2148 * Cache charges(val) to local per_cpu area.
2149 * This will be consumed by consume_stock() function, later.
2151 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2153 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2155 if (stock
->cached
!= memcg
) { /* reset if necessary */
2157 stock
->cached
= memcg
;
2159 stock
->nr_pages
+= nr_pages
;
2160 put_cpu_var(memcg_stock
);
2164 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2165 * of the hierarchy under it.
2167 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
2171 /* If someone's already draining, avoid adding running more workers. */
2172 if (!mutex_trylock(&percpu_charge_mutex
))
2174 /* Notify other cpus that system-wide "drain" is running */
2177 for_each_online_cpu(cpu
) {
2178 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2179 struct mem_cgroup
*memcg
;
2181 memcg
= stock
->cached
;
2182 if (!memcg
|| !stock
->nr_pages
)
2184 if (!mem_cgroup_is_descendant(memcg
, root_memcg
))
2186 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2188 drain_local_stock(&stock
->work
);
2190 schedule_work_on(cpu
, &stock
->work
);
2195 mutex_unlock(&percpu_charge_mutex
);
2199 * This function drains percpu counter value from DEAD cpu and
2200 * move it to local cpu. Note that this function can be preempted.
2202 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2206 spin_lock(&memcg
->pcp_counter_lock
);
2207 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2208 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2210 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2211 memcg
->nocpu_base
.count
[i
] += x
;
2213 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2214 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2216 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2217 memcg
->nocpu_base
.events
[i
] += x
;
2219 spin_unlock(&memcg
->pcp_counter_lock
);
2222 static int memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2223 unsigned long action
,
2226 int cpu
= (unsigned long)hcpu
;
2227 struct memcg_stock_pcp
*stock
;
2228 struct mem_cgroup
*iter
;
2230 if (action
== CPU_ONLINE
)
2233 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2236 for_each_mem_cgroup(iter
)
2237 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2239 stock
= &per_cpu(memcg_stock
, cpu
);
2244 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2245 unsigned int nr_pages
)
2247 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2248 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2249 struct mem_cgroup
*mem_over_limit
;
2250 struct page_counter
*counter
;
2251 unsigned long nr_reclaimed
;
2252 bool may_swap
= true;
2253 bool drained
= false;
2256 if (mem_cgroup_is_root(memcg
))
2259 if (consume_stock(memcg
, nr_pages
))
2262 if (!do_swap_account
||
2263 !page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
2264 if (!page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
2266 if (do_swap_account
)
2267 page_counter_uncharge(&memcg
->memsw
, batch
);
2268 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
2270 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
2274 if (batch
> nr_pages
) {
2280 * Unlike in global OOM situations, memcg is not in a physical
2281 * memory shortage. Allow dying and OOM-killed tasks to
2282 * bypass the last charges so that they can exit quickly and
2283 * free their memory.
2285 if (unlikely(test_thread_flag(TIF_MEMDIE
) ||
2286 fatal_signal_pending(current
) ||
2287 current
->flags
& PF_EXITING
))
2290 if (unlikely(task_in_memcg_oom(current
)))
2293 if (!(gfp_mask
& __GFP_WAIT
))
2296 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
2297 gfp_mask
, may_swap
);
2299 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2303 drain_all_stock(mem_over_limit
);
2308 if (gfp_mask
& __GFP_NORETRY
)
2311 * Even though the limit is exceeded at this point, reclaim
2312 * may have been able to free some pages. Retry the charge
2313 * before killing the task.
2315 * Only for regular pages, though: huge pages are rather
2316 * unlikely to succeed so close to the limit, and we fall back
2317 * to regular pages anyway in case of failure.
2319 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
2322 * At task move, charge accounts can be doubly counted. So, it's
2323 * better to wait until the end of task_move if something is going on.
2325 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2331 if (gfp_mask
& __GFP_NOFAIL
)
2334 if (fatal_signal_pending(current
))
2337 mem_cgroup_oom(mem_over_limit
, gfp_mask
, get_order(nr_pages
));
2339 if (!(gfp_mask
& __GFP_NOFAIL
))
2345 css_get_many(&memcg
->css
, batch
);
2346 if (batch
> nr_pages
)
2347 refill_stock(memcg
, batch
- nr_pages
);
2352 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2354 if (mem_cgroup_is_root(memcg
))
2357 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2358 if (do_swap_account
)
2359 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2361 css_put_many(&memcg
->css
, nr_pages
);
2365 * A helper function to get mem_cgroup from ID. must be called under
2366 * rcu_read_lock(). The caller is responsible for calling
2367 * css_tryget_online() if the mem_cgroup is used for charging. (dropping
2368 * refcnt from swap can be called against removed memcg.)
2370 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2372 /* ID 0 is unused ID */
2375 return mem_cgroup_from_id(id
);
2379 * try_get_mem_cgroup_from_page - look up page's memcg association
2382 * Look up, get a css reference, and return the memcg that owns @page.
2384 * The page must be locked to prevent racing with swap-in and page
2385 * cache charges. If coming from an unlocked page table, the caller
2386 * must ensure the page is on the LRU or this can race with charging.
2388 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2390 struct mem_cgroup
*memcg
;
2394 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
2396 memcg
= page
->mem_cgroup
;
2398 if (!css_tryget_online(&memcg
->css
))
2400 } else if (PageSwapCache(page
)) {
2401 ent
.val
= page_private(page
);
2402 id
= lookup_swap_cgroup_id(ent
);
2404 memcg
= mem_cgroup_lookup(id
);
2405 if (memcg
&& !css_tryget_online(&memcg
->css
))
2412 static void lock_page_lru(struct page
*page
, int *isolated
)
2414 struct zone
*zone
= page_zone(page
);
2416 spin_lock_irq(&zone
->lru_lock
);
2417 if (PageLRU(page
)) {
2418 struct lruvec
*lruvec
;
2420 lruvec
= mem_cgroup_page_lruvec(page
, zone
);
2422 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2428 static void unlock_page_lru(struct page
*page
, int isolated
)
2430 struct zone
*zone
= page_zone(page
);
2433 struct lruvec
*lruvec
;
2435 lruvec
= mem_cgroup_page_lruvec(page
, zone
);
2436 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2438 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2440 spin_unlock_irq(&zone
->lru_lock
);
2443 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2448 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2451 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2452 * may already be on some other mem_cgroup's LRU. Take care of it.
2455 lock_page_lru(page
, &isolated
);
2458 * Nobody should be changing or seriously looking at
2459 * page->mem_cgroup at this point:
2461 * - the page is uncharged
2463 * - the page is off-LRU
2465 * - an anonymous fault has exclusive page access, except for
2466 * a locked page table
2468 * - a page cache insertion, a swapin fault, or a migration
2469 * have the page locked
2471 page
->mem_cgroup
= memcg
;
2474 unlock_page_lru(page
, isolated
);
2477 #ifdef CONFIG_MEMCG_KMEM
2479 * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
2480 * destroyed. It protects memcg_caches arrays and memcg_slab_caches lists.
2482 static DEFINE_MUTEX(memcg_slab_mutex
);
2485 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2486 * in the memcg_cache_params struct.
2488 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2490 struct kmem_cache
*cachep
;
2492 VM_BUG_ON(p
->is_root_cache
);
2493 cachep
= p
->root_cache
;
2494 return cache_from_memcg_idx(cachep
, memcg_cache_id(p
->memcg
));
2497 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
,
2498 unsigned long nr_pages
)
2500 struct page_counter
*counter
;
2503 ret
= page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
);
2507 ret
= try_charge(memcg
, gfp
, nr_pages
);
2508 if (ret
== -EINTR
) {
2510 * try_charge() chose to bypass to root due to OOM kill or
2511 * fatal signal. Since our only options are to either fail
2512 * the allocation or charge it to this cgroup, do it as a
2513 * temporary condition. But we can't fail. From a kmem/slab
2514 * perspective, the cache has already been selected, by
2515 * mem_cgroup_kmem_get_cache(), so it is too late to change
2518 * This condition will only trigger if the task entered
2519 * memcg_charge_kmem in a sane state, but was OOM-killed
2520 * during try_charge() above. Tasks that were already dying
2521 * when the allocation triggers should have been already
2522 * directed to the root cgroup in memcontrol.h
2524 page_counter_charge(&memcg
->memory
, nr_pages
);
2525 if (do_swap_account
)
2526 page_counter_charge(&memcg
->memsw
, nr_pages
);
2527 css_get_many(&memcg
->css
, nr_pages
);
2530 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2535 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
,
2536 unsigned long nr_pages
)
2538 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2539 if (do_swap_account
)
2540 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2542 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2544 css_put_many(&memcg
->css
, nr_pages
);
2548 * helper for acessing a memcg's index. It will be used as an index in the
2549 * child cache array in kmem_cache, and also to derive its name. This function
2550 * will return -1 when this is not a kmem-limited memcg.
2552 int memcg_cache_id(struct mem_cgroup
*memcg
)
2554 return memcg
? memcg
->kmemcg_id
: -1;
2557 static int memcg_alloc_cache_id(void)
2562 id
= ida_simple_get(&kmem_limited_groups
,
2563 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2567 if (id
< memcg_limited_groups_array_size
)
2571 * There's no space for the new id in memcg_caches arrays,
2572 * so we have to grow them.
2575 size
= 2 * (id
+ 1);
2576 if (size
< MEMCG_CACHES_MIN_SIZE
)
2577 size
= MEMCG_CACHES_MIN_SIZE
;
2578 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2579 size
= MEMCG_CACHES_MAX_SIZE
;
2581 mutex_lock(&memcg_slab_mutex
);
2582 err
= memcg_update_all_caches(size
);
2583 mutex_unlock(&memcg_slab_mutex
);
2586 ida_simple_remove(&kmem_limited_groups
, id
);
2592 static void memcg_free_cache_id(int id
)
2594 ida_simple_remove(&kmem_limited_groups
, id
);
2598 * We should update the current array size iff all caches updates succeed. This
2599 * can only be done from the slab side. The slab mutex needs to be held when
2602 void memcg_update_array_size(int num
)
2604 memcg_limited_groups_array_size
= num
;
2607 static void memcg_register_cache(struct mem_cgroup
*memcg
,
2608 struct kmem_cache
*root_cache
)
2610 static char memcg_name_buf
[NAME_MAX
+ 1]; /* protected by
2612 struct kmem_cache
*cachep
;
2615 lockdep_assert_held(&memcg_slab_mutex
);
2617 id
= memcg_cache_id(memcg
);
2620 * Since per-memcg caches are created asynchronously on first
2621 * allocation (see memcg_kmem_get_cache()), several threads can try to
2622 * create the same cache, but only one of them may succeed.
2624 if (cache_from_memcg_idx(root_cache
, id
))
2627 cgroup_name(memcg
->css
.cgroup
, memcg_name_buf
, NAME_MAX
+ 1);
2628 cachep
= memcg_create_kmem_cache(memcg
, root_cache
, memcg_name_buf
);
2630 * If we could not create a memcg cache, do not complain, because
2631 * that's not critical at all as we can always proceed with the root
2637 css_get(&memcg
->css
);
2638 list_add(&cachep
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
2641 * Since readers won't lock (see cache_from_memcg_idx()), we need a
2642 * barrier here to ensure nobody will see the kmem_cache partially
2647 BUG_ON(root_cache
->memcg_params
->memcg_caches
[id
]);
2648 root_cache
->memcg_params
->memcg_caches
[id
] = cachep
;
2651 static void memcg_unregister_cache(struct kmem_cache
*cachep
)
2653 struct kmem_cache
*root_cache
;
2654 struct mem_cgroup
*memcg
;
2657 lockdep_assert_held(&memcg_slab_mutex
);
2659 BUG_ON(is_root_cache(cachep
));
2661 root_cache
= cachep
->memcg_params
->root_cache
;
2662 memcg
= cachep
->memcg_params
->memcg
;
2663 id
= memcg_cache_id(memcg
);
2665 BUG_ON(root_cache
->memcg_params
->memcg_caches
[id
] != cachep
);
2666 root_cache
->memcg_params
->memcg_caches
[id
] = NULL
;
2668 list_del(&cachep
->memcg_params
->list
);
2670 kmem_cache_destroy(cachep
);
2672 /* drop the reference taken in memcg_register_cache */
2673 css_put(&memcg
->css
);
2677 * During the creation a new cache, we need to disable our accounting mechanism
2678 * altogether. This is true even if we are not creating, but rather just
2679 * enqueing new caches to be created.
2681 * This is because that process will trigger allocations; some visible, like
2682 * explicit kmallocs to auxiliary data structures, name strings and internal
2683 * cache structures; some well concealed, like INIT_WORK() that can allocate
2684 * objects during debug.
2686 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
2687 * to it. This may not be a bounded recursion: since the first cache creation
2688 * failed to complete (waiting on the allocation), we'll just try to create the
2689 * cache again, failing at the same point.
2691 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
2692 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
2693 * inside the following two functions.
2695 static inline void memcg_stop_kmem_account(void)
2697 VM_BUG_ON(!current
->mm
);
2698 current
->memcg_kmem_skip_account
++;
2701 static inline void memcg_resume_kmem_account(void)
2703 VM_BUG_ON(!current
->mm
);
2704 current
->memcg_kmem_skip_account
--;
2707 int __memcg_cleanup_cache_params(struct kmem_cache
*s
)
2709 struct kmem_cache
*c
;
2712 mutex_lock(&memcg_slab_mutex
);
2713 for_each_memcg_cache_index(i
) {
2714 c
= cache_from_memcg_idx(s
, i
);
2718 memcg_unregister_cache(c
);
2720 if (cache_from_memcg_idx(s
, i
))
2723 mutex_unlock(&memcg_slab_mutex
);
2727 static void memcg_unregister_all_caches(struct mem_cgroup
*memcg
)
2729 struct kmem_cache
*cachep
;
2730 struct memcg_cache_params
*params
, *tmp
;
2732 if (!memcg_kmem_is_active(memcg
))
2735 mutex_lock(&memcg_slab_mutex
);
2736 list_for_each_entry_safe(params
, tmp
, &memcg
->memcg_slab_caches
, list
) {
2737 cachep
= memcg_params_to_cache(params
);
2738 kmem_cache_shrink(cachep
);
2739 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
2740 memcg_unregister_cache(cachep
);
2742 mutex_unlock(&memcg_slab_mutex
);
2745 struct memcg_register_cache_work
{
2746 struct mem_cgroup
*memcg
;
2747 struct kmem_cache
*cachep
;
2748 struct work_struct work
;
2751 static void memcg_register_cache_func(struct work_struct
*w
)
2753 struct memcg_register_cache_work
*cw
=
2754 container_of(w
, struct memcg_register_cache_work
, work
);
2755 struct mem_cgroup
*memcg
= cw
->memcg
;
2756 struct kmem_cache
*cachep
= cw
->cachep
;
2758 mutex_lock(&memcg_slab_mutex
);
2759 memcg_register_cache(memcg
, cachep
);
2760 mutex_unlock(&memcg_slab_mutex
);
2762 css_put(&memcg
->css
);
2767 * Enqueue the creation of a per-memcg kmem_cache.
2769 static void __memcg_schedule_register_cache(struct mem_cgroup
*memcg
,
2770 struct kmem_cache
*cachep
)
2772 struct memcg_register_cache_work
*cw
;
2774 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
);
2776 css_put(&memcg
->css
);
2781 cw
->cachep
= cachep
;
2783 INIT_WORK(&cw
->work
, memcg_register_cache_func
);
2784 schedule_work(&cw
->work
);
2787 static void memcg_schedule_register_cache(struct mem_cgroup
*memcg
,
2788 struct kmem_cache
*cachep
)
2791 * We need to stop accounting when we kmalloc, because if the
2792 * corresponding kmalloc cache is not yet created, the first allocation
2793 * in __memcg_schedule_register_cache will recurse.
2795 * However, it is better to enclose the whole function. Depending on
2796 * the debugging options enabled, INIT_WORK(), for instance, can
2797 * trigger an allocation. This too, will make us recurse. Because at
2798 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2799 * the safest choice is to do it like this, wrapping the whole function.
2801 memcg_stop_kmem_account();
2802 __memcg_schedule_register_cache(memcg
, cachep
);
2803 memcg_resume_kmem_account();
2806 int __memcg_charge_slab(struct kmem_cache
*cachep
, gfp_t gfp
, int order
)
2808 unsigned int nr_pages
= 1 << order
;
2811 res
= memcg_charge_kmem(cachep
->memcg_params
->memcg
, gfp
, nr_pages
);
2813 atomic_add(nr_pages
, &cachep
->memcg_params
->nr_pages
);
2817 void __memcg_uncharge_slab(struct kmem_cache
*cachep
, int order
)
2819 unsigned int nr_pages
= 1 << order
;
2821 memcg_uncharge_kmem(cachep
->memcg_params
->memcg
, nr_pages
);
2822 atomic_sub(nr_pages
, &cachep
->memcg_params
->nr_pages
);
2826 * Return the kmem_cache we're supposed to use for a slab allocation.
2827 * We try to use the current memcg's version of the cache.
2829 * If the cache does not exist yet, if we are the first user of it,
2830 * we either create it immediately, if possible, or create it asynchronously
2832 * In the latter case, we will let the current allocation go through with
2833 * the original cache.
2835 * Can't be called in interrupt context or from kernel threads.
2836 * This function needs to be called with rcu_read_lock() held.
2838 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
2841 struct mem_cgroup
*memcg
;
2842 struct kmem_cache
*memcg_cachep
;
2844 VM_BUG_ON(!cachep
->memcg_params
);
2845 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
2847 if (current
->memcg_kmem_skip_account
)
2851 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
2853 if (!memcg_kmem_is_active(memcg
))
2856 memcg_cachep
= cache_from_memcg_idx(cachep
, memcg_cache_id(memcg
));
2857 if (likely(memcg_cachep
)) {
2858 cachep
= memcg_cachep
;
2862 /* The corresponding put will be done in the workqueue. */
2863 if (!css_tryget_online(&memcg
->css
))
2868 * If we are in a safe context (can wait, and not in interrupt
2869 * context), we could be be predictable and return right away.
2870 * This would guarantee that the allocation being performed
2871 * already belongs in the new cache.
2873 * However, there are some clashes that can arrive from locking.
2874 * For instance, because we acquire the slab_mutex while doing
2875 * memcg_create_kmem_cache, this means no further allocation
2876 * could happen with the slab_mutex held. So it's better to
2879 memcg_schedule_register_cache(memcg
, cachep
);
2887 * We need to verify if the allocation against current->mm->owner's memcg is
2888 * possible for the given order. But the page is not allocated yet, so we'll
2889 * need a further commit step to do the final arrangements.
2891 * It is possible for the task to switch cgroups in this mean time, so at
2892 * commit time, we can't rely on task conversion any longer. We'll then use
2893 * the handle argument to return to the caller which cgroup we should commit
2894 * against. We could also return the memcg directly and avoid the pointer
2895 * passing, but a boolean return value gives better semantics considering
2896 * the compiled-out case as well.
2898 * Returning true means the allocation is possible.
2901 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
2903 struct mem_cgroup
*memcg
;
2909 * Disabling accounting is only relevant for some specific memcg
2910 * internal allocations. Therefore we would initially not have such
2911 * check here, since direct calls to the page allocator that are
2912 * accounted to kmemcg (alloc_kmem_pages and friends) only happen
2913 * outside memcg core. We are mostly concerned with cache allocations,
2914 * and by having this test at memcg_kmem_get_cache, we are already able
2915 * to relay the allocation to the root cache and bypass the memcg cache
2918 * There is one exception, though: the SLUB allocator does not create
2919 * large order caches, but rather service large kmallocs directly from
2920 * the page allocator. Therefore, the following sequence when backed by
2921 * the SLUB allocator:
2923 * memcg_stop_kmem_account();
2924 * kmalloc(<large_number>)
2925 * memcg_resume_kmem_account();
2927 * would effectively ignore the fact that we should skip accounting,
2928 * since it will drive us directly to this function without passing
2929 * through the cache selector memcg_kmem_get_cache. Such large
2930 * allocations are extremely rare but can happen, for instance, for the
2931 * cache arrays. We bring this test here.
2933 if (current
->memcg_kmem_skip_account
)
2936 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2938 if (!memcg_kmem_is_active(memcg
)) {
2939 css_put(&memcg
->css
);
2943 ret
= memcg_charge_kmem(memcg
, gfp
, 1 << order
);
2947 css_put(&memcg
->css
);
2951 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2954 VM_BUG_ON(mem_cgroup_is_root(memcg
));
2956 /* The page allocation failed. Revert */
2958 memcg_uncharge_kmem(memcg
, 1 << order
);
2961 page
->mem_cgroup
= memcg
;
2964 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
2966 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
2971 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
2973 memcg_uncharge_kmem(memcg
, 1 << order
);
2974 page
->mem_cgroup
= NULL
;
2977 static inline void memcg_unregister_all_caches(struct mem_cgroup
*memcg
)
2980 #endif /* CONFIG_MEMCG_KMEM */
2982 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2985 * Because tail pages are not marked as "used", set it. We're under
2986 * zone->lru_lock, 'splitting on pmd' and compound_lock.
2987 * charge/uncharge will be never happen and move_account() is done under
2988 * compound_lock(), so we don't have to take care of races.
2990 void mem_cgroup_split_huge_fixup(struct page
*head
)
2994 if (mem_cgroup_disabled())
2997 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
2998 head
[i
].mem_cgroup
= head
->mem_cgroup
;
3000 __this_cpu_sub(head
->mem_cgroup
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
3003 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3006 * mem_cgroup_move_account - move account of the page
3008 * @nr_pages: number of regular pages (>1 for huge pages)
3009 * @from: mem_cgroup which the page is moved from.
3010 * @to: mem_cgroup which the page is moved to. @from != @to.
3012 * The caller must confirm following.
3013 * - page is not on LRU (isolate_page() is useful.)
3014 * - compound_lock is held when nr_pages > 1
3016 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3019 static int mem_cgroup_move_account(struct page
*page
,
3020 unsigned int nr_pages
,
3021 struct mem_cgroup
*from
,
3022 struct mem_cgroup
*to
)
3024 unsigned long flags
;
3027 VM_BUG_ON(from
== to
);
3028 VM_BUG_ON_PAGE(PageLRU(page
), page
);
3030 * The page is isolated from LRU. So, collapse function
3031 * will not handle this page. But page splitting can happen.
3032 * Do this check under compound_page_lock(). The caller should
3036 if (nr_pages
> 1 && !PageTransHuge(page
))
3040 * Prevent mem_cgroup_migrate() from looking at page->mem_cgroup
3041 * of its source page while we change it: page migration takes
3042 * both pages off the LRU, but page cache replacement doesn't.
3044 if (!trylock_page(page
))
3048 if (page
->mem_cgroup
!= from
)
3051 spin_lock_irqsave(&from
->move_lock
, flags
);
3053 if (!PageAnon(page
) && page_mapped(page
)) {
3054 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
3056 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
3060 if (PageWriteback(page
)) {
3061 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
3063 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
3068 * It is safe to change page->mem_cgroup here because the page
3069 * is referenced, charged, and isolated - we can't race with
3070 * uncharging, charging, migration, or LRU putback.
3073 /* caller should have done css_get */
3074 page
->mem_cgroup
= to
;
3075 spin_unlock_irqrestore(&from
->move_lock
, flags
);
3079 local_irq_disable();
3080 mem_cgroup_charge_statistics(to
, page
, nr_pages
);
3081 memcg_check_events(to
, page
);
3082 mem_cgroup_charge_statistics(from
, page
, -nr_pages
);
3083 memcg_check_events(from
, page
);
3091 #ifdef CONFIG_MEMCG_SWAP
3092 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
3095 int val
= (charge
) ? 1 : -1;
3096 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
3100 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3101 * @entry: swap entry to be moved
3102 * @from: mem_cgroup which the entry is moved from
3103 * @to: mem_cgroup which the entry is moved to
3105 * It succeeds only when the swap_cgroup's record for this entry is the same
3106 * as the mem_cgroup's id of @from.
3108 * Returns 0 on success, -EINVAL on failure.
3110 * The caller must have charged to @to, IOW, called page_counter_charge() about
3111 * both res and memsw, and called css_get().
3113 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3114 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3116 unsigned short old_id
, new_id
;
3118 old_id
= mem_cgroup_id(from
);
3119 new_id
= mem_cgroup_id(to
);
3121 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3122 mem_cgroup_swap_statistics(from
, false);
3123 mem_cgroup_swap_statistics(to
, true);
3125 * This function is only called from task migration context now.
3126 * It postpones page_counter and refcount handling till the end
3127 * of task migration(mem_cgroup_clear_mc()) for performance
3128 * improvement. But we cannot postpone css_get(to) because if
3129 * the process that has been moved to @to does swap-in, the
3130 * refcount of @to might be decreased to 0.
3132 * We are in attach() phase, so the cgroup is guaranteed to be
3133 * alive, so we can just call css_get().
3141 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3142 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3148 static DEFINE_MUTEX(memcg_limit_mutex
);
3150 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
3151 unsigned long limit
)
3153 unsigned long curusage
;
3154 unsigned long oldusage
;
3155 bool enlarge
= false;
3160 * For keeping hierarchical_reclaim simple, how long we should retry
3161 * is depends on callers. We set our retry-count to be function
3162 * of # of children which we should visit in this loop.
3164 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
3165 mem_cgroup_count_children(memcg
);
3167 oldusage
= page_counter_read(&memcg
->memory
);
3170 if (signal_pending(current
)) {
3175 mutex_lock(&memcg_limit_mutex
);
3176 if (limit
> memcg
->memsw
.limit
) {
3177 mutex_unlock(&memcg_limit_mutex
);
3181 if (limit
> memcg
->memory
.limit
)
3183 ret
= page_counter_limit(&memcg
->memory
, limit
);
3184 mutex_unlock(&memcg_limit_mutex
);
3189 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, true);
3191 curusage
= page_counter_read(&memcg
->memory
);
3192 /* Usage is reduced ? */
3193 if (curusage
>= oldusage
)
3196 oldusage
= curusage
;
3197 } while (retry_count
);
3199 if (!ret
&& enlarge
)
3200 memcg_oom_recover(memcg
);
3205 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
3206 unsigned long limit
)
3208 unsigned long curusage
;
3209 unsigned long oldusage
;
3210 bool enlarge
= false;
3214 /* see mem_cgroup_resize_res_limit */
3215 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
3216 mem_cgroup_count_children(memcg
);
3218 oldusage
= page_counter_read(&memcg
->memsw
);
3221 if (signal_pending(current
)) {
3226 mutex_lock(&memcg_limit_mutex
);
3227 if (limit
< memcg
->memory
.limit
) {
3228 mutex_unlock(&memcg_limit_mutex
);
3232 if (limit
> memcg
->memsw
.limit
)
3234 ret
= page_counter_limit(&memcg
->memsw
, limit
);
3235 mutex_unlock(&memcg_limit_mutex
);
3240 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, false);
3242 curusage
= page_counter_read(&memcg
->memsw
);
3243 /* Usage is reduced ? */
3244 if (curusage
>= oldusage
)
3247 oldusage
= curusage
;
3248 } while (retry_count
);
3250 if (!ret
&& enlarge
)
3251 memcg_oom_recover(memcg
);
3256 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
3258 unsigned long *total_scanned
)
3260 unsigned long nr_reclaimed
= 0;
3261 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
3262 unsigned long reclaimed
;
3264 struct mem_cgroup_tree_per_zone
*mctz
;
3265 unsigned long excess
;
3266 unsigned long nr_scanned
;
3271 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
3273 * This loop can run a while, specially if mem_cgroup's continuously
3274 * keep exceeding their soft limit and putting the system under
3281 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3286 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
3287 gfp_mask
, &nr_scanned
);
3288 nr_reclaimed
+= reclaimed
;
3289 *total_scanned
+= nr_scanned
;
3290 spin_lock_irq(&mctz
->lock
);
3291 __mem_cgroup_remove_exceeded(mz
, mctz
);
3294 * If we failed to reclaim anything from this memory cgroup
3295 * it is time to move on to the next cgroup
3299 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
3301 excess
= soft_limit_excess(mz
->memcg
);
3303 * One school of thought says that we should not add
3304 * back the node to the tree if reclaim returns 0.
3305 * But our reclaim could return 0, simply because due
3306 * to priority we are exposing a smaller subset of
3307 * memory to reclaim from. Consider this as a longer
3310 /* If excess == 0, no tree ops */
3311 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
3312 spin_unlock_irq(&mctz
->lock
);
3313 css_put(&mz
->memcg
->css
);
3316 * Could not reclaim anything and there are no more
3317 * mem cgroups to try or we seem to be looping without
3318 * reclaiming anything.
3320 if (!nr_reclaimed
&&
3322 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3324 } while (!nr_reclaimed
);
3326 css_put(&next_mz
->memcg
->css
);
3327 return nr_reclaimed
;
3331 * Test whether @memcg has children, dead or alive. Note that this
3332 * function doesn't care whether @memcg has use_hierarchy enabled and
3333 * returns %true if there are child csses according to the cgroup
3334 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
3336 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
3341 * The lock does not prevent addition or deletion of children, but
3342 * it prevents a new child from being initialized based on this
3343 * parent in css_online(), so it's enough to decide whether
3344 * hierarchically inherited attributes can still be changed or not.
3346 lockdep_assert_held(&memcg_create_mutex
);
3349 ret
= css_next_child(NULL
, &memcg
->css
);
3355 * Reclaims as many pages from the given memcg as possible and moves
3356 * the rest to the parent.
3358 * Caller is responsible for holding css reference for memcg.
3360 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3362 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
3364 /* we call try-to-free pages for make this cgroup empty */
3365 lru_add_drain_all();
3366 /* try to free all pages in this cgroup */
3367 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
3370 if (signal_pending(current
))
3373 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
3377 /* maybe some writeback is necessary */
3378 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3386 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
3387 char *buf
, size_t nbytes
,
3390 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3392 if (mem_cgroup_is_root(memcg
))
3394 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
3397 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
3400 return mem_cgroup_from_css(css
)->use_hierarchy
;
3403 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
3404 struct cftype
*cft
, u64 val
)
3407 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3408 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
3410 mutex_lock(&memcg_create_mutex
);
3412 if (memcg
->use_hierarchy
== val
)
3416 * If parent's use_hierarchy is set, we can't make any modifications
3417 * in the child subtrees. If it is unset, then the change can
3418 * occur, provided the current cgroup has no children.
3420 * For the root cgroup, parent_mem is NULL, we allow value to be
3421 * set if there are no children.
3423 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
3424 (val
== 1 || val
== 0)) {
3425 if (!memcg_has_children(memcg
))
3426 memcg
->use_hierarchy
= val
;
3433 mutex_unlock(&memcg_create_mutex
);
3438 static unsigned long tree_stat(struct mem_cgroup
*memcg
,
3439 enum mem_cgroup_stat_index idx
)
3441 struct mem_cgroup
*iter
;
3444 /* Per-cpu values can be negative, use a signed accumulator */
3445 for_each_mem_cgroup_tree(iter
, memcg
)
3446 val
+= mem_cgroup_read_stat(iter
, idx
);
3448 if (val
< 0) /* race ? */
3453 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3457 if (mem_cgroup_is_root(memcg
)) {
3458 val
= tree_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
3459 val
+= tree_stat(memcg
, MEM_CGROUP_STAT_RSS
);
3461 val
+= tree_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
3464 val
= page_counter_read(&memcg
->memory
);
3466 val
= page_counter_read(&memcg
->memsw
);
3468 return val
<< PAGE_SHIFT
;
3479 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
3482 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3483 struct page_counter
*counter
;
3485 switch (MEMFILE_TYPE(cft
->private)) {
3487 counter
= &memcg
->memory
;
3490 counter
= &memcg
->memsw
;
3493 counter
= &memcg
->kmem
;
3499 switch (MEMFILE_ATTR(cft
->private)) {
3501 if (counter
== &memcg
->memory
)
3502 return mem_cgroup_usage(memcg
, false);
3503 if (counter
== &memcg
->memsw
)
3504 return mem_cgroup_usage(memcg
, true);
3505 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
3507 return (u64
)counter
->limit
* PAGE_SIZE
;
3509 return (u64
)counter
->watermark
* PAGE_SIZE
;
3511 return counter
->failcnt
;
3512 case RES_SOFT_LIMIT
:
3513 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
3519 #ifdef CONFIG_MEMCG_KMEM
3520 static int memcg_activate_kmem(struct mem_cgroup
*memcg
,
3521 unsigned long nr_pages
)
3526 if (memcg_kmem_is_active(memcg
))
3530 * For simplicity, we won't allow this to be disabled. It also can't
3531 * be changed if the cgroup has children already, or if tasks had
3534 * If tasks join before we set the limit, a person looking at
3535 * kmem.usage_in_bytes will have no way to determine when it took
3536 * place, which makes the value quite meaningless.
3538 * After it first became limited, changes in the value of the limit are
3539 * of course permitted.
3541 mutex_lock(&memcg_create_mutex
);
3542 if (cgroup_has_tasks(memcg
->css
.cgroup
) ||
3543 (memcg
->use_hierarchy
&& memcg_has_children(memcg
)))
3545 mutex_unlock(&memcg_create_mutex
);
3549 memcg_id
= memcg_alloc_cache_id();
3556 * We couldn't have accounted to this cgroup, because it hasn't got
3557 * activated yet, so this should succeed.
3559 err
= page_counter_limit(&memcg
->kmem
, nr_pages
);
3562 static_key_slow_inc(&memcg_kmem_enabled_key
);
3564 * A memory cgroup is considered kmem-active as soon as it gets
3565 * kmemcg_id. Setting the id after enabling static branching will
3566 * guarantee no one starts accounting before all call sites are
3569 memcg
->kmemcg_id
= memcg_id
;
3574 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
3575 unsigned long limit
)
3579 mutex_lock(&memcg_limit_mutex
);
3580 if (!memcg_kmem_is_active(memcg
))
3581 ret
= memcg_activate_kmem(memcg
, limit
);
3583 ret
= page_counter_limit(&memcg
->kmem
, limit
);
3584 mutex_unlock(&memcg_limit_mutex
);
3588 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
3591 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
3596 mutex_lock(&memcg_limit_mutex
);
3598 * If the parent cgroup is not kmem-active now, it cannot be activated
3599 * after this point, because it has at least one child already.
3601 if (memcg_kmem_is_active(parent
))
3602 ret
= memcg_activate_kmem(memcg
, PAGE_COUNTER_MAX
);
3603 mutex_unlock(&memcg_limit_mutex
);
3607 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
3608 unsigned long limit
)
3612 #endif /* CONFIG_MEMCG_KMEM */
3615 * The user of this function is...
3618 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
3619 char *buf
, size_t nbytes
, loff_t off
)
3621 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3622 unsigned long nr_pages
;
3625 buf
= strstrip(buf
);
3626 ret
= page_counter_memparse(buf
, &nr_pages
);
3630 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3632 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3636 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3638 ret
= mem_cgroup_resize_limit(memcg
, nr_pages
);
3641 ret
= mem_cgroup_resize_memsw_limit(memcg
, nr_pages
);
3644 ret
= memcg_update_kmem_limit(memcg
, nr_pages
);
3648 case RES_SOFT_LIMIT
:
3649 memcg
->soft_limit
= nr_pages
;
3653 return ret
?: nbytes
;
3656 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3657 size_t nbytes
, loff_t off
)
3659 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3660 struct page_counter
*counter
;
3662 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3664 counter
= &memcg
->memory
;
3667 counter
= &memcg
->memsw
;
3670 counter
= &memcg
->kmem
;
3676 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3678 page_counter_reset_watermark(counter
);
3681 counter
->failcnt
= 0;
3690 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3693 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3697 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3698 struct cftype
*cft
, u64 val
)
3700 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3702 if (val
>= (1 << NR_MOVE_TYPE
))
3706 * No kind of locking is needed in here, because ->can_attach() will
3707 * check this value once in the beginning of the process, and then carry
3708 * on with stale data. This means that changes to this value will only
3709 * affect task migrations starting after the change.
3711 memcg
->move_charge_at_immigrate
= val
;
3715 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3716 struct cftype
*cft
, u64 val
)
3723 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3727 unsigned int lru_mask
;
3730 static const struct numa_stat stats
[] = {
3731 { "total", LRU_ALL
},
3732 { "file", LRU_ALL_FILE
},
3733 { "anon", LRU_ALL_ANON
},
3734 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3736 const struct numa_stat
*stat
;
3739 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3741 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3742 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
3743 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
3744 for_each_node_state(nid
, N_MEMORY
) {
3745 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3747 seq_printf(m
, " N%d=%lu", nid
, nr
);
3752 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3753 struct mem_cgroup
*iter
;
3756 for_each_mem_cgroup_tree(iter
, memcg
)
3757 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
3758 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
3759 for_each_node_state(nid
, N_MEMORY
) {
3761 for_each_mem_cgroup_tree(iter
, memcg
)
3762 nr
+= mem_cgroup_node_nr_lru_pages(
3763 iter
, nid
, stat
->lru_mask
);
3764 seq_printf(m
, " N%d=%lu", nid
, nr
);
3771 #endif /* CONFIG_NUMA */
3773 static inline void mem_cgroup_lru_names_not_uptodate(void)
3775 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
3778 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3780 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3781 unsigned long memory
, memsw
;
3782 struct mem_cgroup
*mi
;
3785 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3786 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
3788 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
3789 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
3792 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
3793 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
3794 mem_cgroup_read_events(memcg
, i
));
3796 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3797 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
3798 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
3800 /* Hierarchical information */
3801 memory
= memsw
= PAGE_COUNTER_MAX
;
3802 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3803 memory
= min(memory
, mi
->memory
.limit
);
3804 memsw
= min(memsw
, mi
->memsw
.limit
);
3806 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3807 (u64
)memory
* PAGE_SIZE
);
3808 if (do_swap_account
)
3809 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3810 (u64
)memsw
* PAGE_SIZE
);
3812 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3815 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
3817 for_each_mem_cgroup_tree(mi
, memcg
)
3818 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
3819 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
3822 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
3823 unsigned long long val
= 0;
3825 for_each_mem_cgroup_tree(mi
, memcg
)
3826 val
+= mem_cgroup_read_events(mi
, i
);
3827 seq_printf(m
, "total_%s %llu\n",
3828 mem_cgroup_events_names
[i
], val
);
3831 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
3832 unsigned long long val
= 0;
3834 for_each_mem_cgroup_tree(mi
, memcg
)
3835 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
3836 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
3839 #ifdef CONFIG_DEBUG_VM
3842 struct mem_cgroup_per_zone
*mz
;
3843 struct zone_reclaim_stat
*rstat
;
3844 unsigned long recent_rotated
[2] = {0, 0};
3845 unsigned long recent_scanned
[2] = {0, 0};
3847 for_each_online_node(nid
)
3848 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
3849 mz
= &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
3850 rstat
= &mz
->lruvec
.reclaim_stat
;
3852 recent_rotated
[0] += rstat
->recent_rotated
[0];
3853 recent_rotated
[1] += rstat
->recent_rotated
[1];
3854 recent_scanned
[0] += rstat
->recent_scanned
[0];
3855 recent_scanned
[1] += rstat
->recent_scanned
[1];
3857 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
3858 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
3859 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
3860 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
3867 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3870 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3872 return mem_cgroup_swappiness(memcg
);
3875 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3876 struct cftype
*cft
, u64 val
)
3878 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3884 memcg
->swappiness
= val
;
3886 vm_swappiness
= val
;
3891 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3893 struct mem_cgroup_threshold_ary
*t
;
3894 unsigned long usage
;
3899 t
= rcu_dereference(memcg
->thresholds
.primary
);
3901 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3906 usage
= mem_cgroup_usage(memcg
, swap
);
3909 * current_threshold points to threshold just below or equal to usage.
3910 * If it's not true, a threshold was crossed after last
3911 * call of __mem_cgroup_threshold().
3913 i
= t
->current_threshold
;
3916 * Iterate backward over array of thresholds starting from
3917 * current_threshold and check if a threshold is crossed.
3918 * If none of thresholds below usage is crossed, we read
3919 * only one element of the array here.
3921 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3922 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3924 /* i = current_threshold + 1 */
3928 * Iterate forward over array of thresholds starting from
3929 * current_threshold+1 and check if a threshold is crossed.
3930 * If none of thresholds above usage is crossed, we read
3931 * only one element of the array here.
3933 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
3934 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3936 /* Update current_threshold */
3937 t
->current_threshold
= i
- 1;
3942 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
3945 __mem_cgroup_threshold(memcg
, false);
3946 if (do_swap_account
)
3947 __mem_cgroup_threshold(memcg
, true);
3949 memcg
= parent_mem_cgroup(memcg
);
3953 static int compare_thresholds(const void *a
, const void *b
)
3955 const struct mem_cgroup_threshold
*_a
= a
;
3956 const struct mem_cgroup_threshold
*_b
= b
;
3958 if (_a
->threshold
> _b
->threshold
)
3961 if (_a
->threshold
< _b
->threshold
)
3967 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
3969 struct mem_cgroup_eventfd_list
*ev
;
3971 spin_lock(&memcg_oom_lock
);
3973 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
3974 eventfd_signal(ev
->eventfd
, 1);
3976 spin_unlock(&memcg_oom_lock
);
3980 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
3982 struct mem_cgroup
*iter
;
3984 for_each_mem_cgroup_tree(iter
, memcg
)
3985 mem_cgroup_oom_notify_cb(iter
);
3988 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3989 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
3991 struct mem_cgroup_thresholds
*thresholds
;
3992 struct mem_cgroup_threshold_ary
*new;
3993 unsigned long threshold
;
3994 unsigned long usage
;
3997 ret
= page_counter_memparse(args
, &threshold
);
4001 mutex_lock(&memcg
->thresholds_lock
);
4004 thresholds
= &memcg
->thresholds
;
4005 usage
= mem_cgroup_usage(memcg
, false);
4006 } else if (type
== _MEMSWAP
) {
4007 thresholds
= &memcg
->memsw_thresholds
;
4008 usage
= mem_cgroup_usage(memcg
, true);
4012 /* Check if a threshold crossed before adding a new one */
4013 if (thresholds
->primary
)
4014 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4016 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4018 /* Allocate memory for new array of thresholds */
4019 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
4027 /* Copy thresholds (if any) to new array */
4028 if (thresholds
->primary
) {
4029 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
4030 sizeof(struct mem_cgroup_threshold
));
4033 /* Add new threshold */
4034 new->entries
[size
- 1].eventfd
= eventfd
;
4035 new->entries
[size
- 1].threshold
= threshold
;
4037 /* Sort thresholds. Registering of new threshold isn't time-critical */
4038 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
4039 compare_thresholds
, NULL
);
4041 /* Find current threshold */
4042 new->current_threshold
= -1;
4043 for (i
= 0; i
< size
; i
++) {
4044 if (new->entries
[i
].threshold
<= usage
) {
4046 * new->current_threshold will not be used until
4047 * rcu_assign_pointer(), so it's safe to increment
4050 ++new->current_threshold
;
4055 /* Free old spare buffer and save old primary buffer as spare */
4056 kfree(thresholds
->spare
);
4057 thresholds
->spare
= thresholds
->primary
;
4059 rcu_assign_pointer(thresholds
->primary
, new);
4061 /* To be sure that nobody uses thresholds */
4065 mutex_unlock(&memcg
->thresholds_lock
);
4070 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4071 struct eventfd_ctx
*eventfd
, const char *args
)
4073 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
4076 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4077 struct eventfd_ctx
*eventfd
, const char *args
)
4079 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
4082 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4083 struct eventfd_ctx
*eventfd
, enum res_type type
)
4085 struct mem_cgroup_thresholds
*thresholds
;
4086 struct mem_cgroup_threshold_ary
*new;
4087 unsigned long usage
;
4090 mutex_lock(&memcg
->thresholds_lock
);
4093 thresholds
= &memcg
->thresholds
;
4094 usage
= mem_cgroup_usage(memcg
, false);
4095 } else if (type
== _MEMSWAP
) {
4096 thresholds
= &memcg
->memsw_thresholds
;
4097 usage
= mem_cgroup_usage(memcg
, true);
4101 if (!thresholds
->primary
)
4104 /* Check if a threshold crossed before removing */
4105 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4107 /* Calculate new number of threshold */
4109 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4110 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4114 new = thresholds
->spare
;
4116 /* Set thresholds array to NULL if we don't have thresholds */
4125 /* Copy thresholds and find current threshold */
4126 new->current_threshold
= -1;
4127 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4128 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4131 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4132 if (new->entries
[j
].threshold
<= usage
) {
4134 * new->current_threshold will not be used
4135 * until rcu_assign_pointer(), so it's safe to increment
4138 ++new->current_threshold
;
4144 /* Swap primary and spare array */
4145 thresholds
->spare
= thresholds
->primary
;
4146 /* If all events are unregistered, free the spare array */
4148 kfree(thresholds
->spare
);
4149 thresholds
->spare
= NULL
;
4152 rcu_assign_pointer(thresholds
->primary
, new);
4154 /* To be sure that nobody uses thresholds */
4157 mutex_unlock(&memcg
->thresholds_lock
);
4160 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4161 struct eventfd_ctx
*eventfd
)
4163 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
4166 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4167 struct eventfd_ctx
*eventfd
)
4169 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
4172 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
4173 struct eventfd_ctx
*eventfd
, const char *args
)
4175 struct mem_cgroup_eventfd_list
*event
;
4177 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4181 spin_lock(&memcg_oom_lock
);
4183 event
->eventfd
= eventfd
;
4184 list_add(&event
->list
, &memcg
->oom_notify
);
4186 /* already in OOM ? */
4187 if (atomic_read(&memcg
->under_oom
))
4188 eventfd_signal(eventfd
, 1);
4189 spin_unlock(&memcg_oom_lock
);
4194 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
4195 struct eventfd_ctx
*eventfd
)
4197 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4199 spin_lock(&memcg_oom_lock
);
4201 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4202 if (ev
->eventfd
== eventfd
) {
4203 list_del(&ev
->list
);
4208 spin_unlock(&memcg_oom_lock
);
4211 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
4213 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
4215 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
4216 seq_printf(sf
, "under_oom %d\n", (bool)atomic_read(&memcg
->under_oom
));
4220 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
4221 struct cftype
*cft
, u64 val
)
4223 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4225 /* cannot set to root cgroup and only 0 and 1 are allowed */
4226 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
4229 memcg
->oom_kill_disable
= val
;
4231 memcg_oom_recover(memcg
);
4236 #ifdef CONFIG_MEMCG_KMEM
4237 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
4241 ret
= memcg_propagate_kmem(memcg
);
4245 return mem_cgroup_sockets_init(memcg
, ss
);
4248 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
4250 mem_cgroup_sockets_destroy(memcg
);
4253 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
4258 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
4264 * DO NOT USE IN NEW FILES.
4266 * "cgroup.event_control" implementation.
4268 * This is way over-engineered. It tries to support fully configurable
4269 * events for each user. Such level of flexibility is completely
4270 * unnecessary especially in the light of the planned unified hierarchy.
4272 * Please deprecate this and replace with something simpler if at all
4277 * Unregister event and free resources.
4279 * Gets called from workqueue.
4281 static void memcg_event_remove(struct work_struct
*work
)
4283 struct mem_cgroup_event
*event
=
4284 container_of(work
, struct mem_cgroup_event
, remove
);
4285 struct mem_cgroup
*memcg
= event
->memcg
;
4287 remove_wait_queue(event
->wqh
, &event
->wait
);
4289 event
->unregister_event(memcg
, event
->eventfd
);
4291 /* Notify userspace the event is going away. */
4292 eventfd_signal(event
->eventfd
, 1);
4294 eventfd_ctx_put(event
->eventfd
);
4296 css_put(&memcg
->css
);
4300 * Gets called on POLLHUP on eventfd when user closes it.
4302 * Called with wqh->lock held and interrupts disabled.
4304 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
4305 int sync
, void *key
)
4307 struct mem_cgroup_event
*event
=
4308 container_of(wait
, struct mem_cgroup_event
, wait
);
4309 struct mem_cgroup
*memcg
= event
->memcg
;
4310 unsigned long flags
= (unsigned long)key
;
4312 if (flags
& POLLHUP
) {
4314 * If the event has been detached at cgroup removal, we
4315 * can simply return knowing the other side will cleanup
4318 * We can't race against event freeing since the other
4319 * side will require wqh->lock via remove_wait_queue(),
4322 spin_lock(&memcg
->event_list_lock
);
4323 if (!list_empty(&event
->list
)) {
4324 list_del_init(&event
->list
);
4326 * We are in atomic context, but cgroup_event_remove()
4327 * may sleep, so we have to call it in workqueue.
4329 schedule_work(&event
->remove
);
4331 spin_unlock(&memcg
->event_list_lock
);
4337 static void memcg_event_ptable_queue_proc(struct file
*file
,
4338 wait_queue_head_t
*wqh
, poll_table
*pt
)
4340 struct mem_cgroup_event
*event
=
4341 container_of(pt
, struct mem_cgroup_event
, pt
);
4344 add_wait_queue(wqh
, &event
->wait
);
4348 * DO NOT USE IN NEW FILES.
4350 * Parse input and register new cgroup event handler.
4352 * Input must be in format '<event_fd> <control_fd> <args>'.
4353 * Interpretation of args is defined by control file implementation.
4355 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
4356 char *buf
, size_t nbytes
, loff_t off
)
4358 struct cgroup_subsys_state
*css
= of_css(of
);
4359 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4360 struct mem_cgroup_event
*event
;
4361 struct cgroup_subsys_state
*cfile_css
;
4362 unsigned int efd
, cfd
;
4369 buf
= strstrip(buf
);
4371 efd
= simple_strtoul(buf
, &endp
, 10);
4376 cfd
= simple_strtoul(buf
, &endp
, 10);
4377 if ((*endp
!= ' ') && (*endp
!= '\0'))
4381 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
4385 event
->memcg
= memcg
;
4386 INIT_LIST_HEAD(&event
->list
);
4387 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
4388 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
4389 INIT_WORK(&event
->remove
, memcg_event_remove
);
4397 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
4398 if (IS_ERR(event
->eventfd
)) {
4399 ret
= PTR_ERR(event
->eventfd
);
4406 goto out_put_eventfd
;
4409 /* the process need read permission on control file */
4410 /* AV: shouldn't we check that it's been opened for read instead? */
4411 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
4416 * Determine the event callbacks and set them in @event. This used
4417 * to be done via struct cftype but cgroup core no longer knows
4418 * about these events. The following is crude but the whole thing
4419 * is for compatibility anyway.
4421 * DO NOT ADD NEW FILES.
4423 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
4425 if (!strcmp(name
, "memory.usage_in_bytes")) {
4426 event
->register_event
= mem_cgroup_usage_register_event
;
4427 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
4428 } else if (!strcmp(name
, "memory.oom_control")) {
4429 event
->register_event
= mem_cgroup_oom_register_event
;
4430 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
4431 } else if (!strcmp(name
, "memory.pressure_level")) {
4432 event
->register_event
= vmpressure_register_event
;
4433 event
->unregister_event
= vmpressure_unregister_event
;
4434 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
4435 event
->register_event
= memsw_cgroup_usage_register_event
;
4436 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
4443 * Verify @cfile should belong to @css. Also, remaining events are
4444 * automatically removed on cgroup destruction but the removal is
4445 * asynchronous, so take an extra ref on @css.
4447 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
4448 &memory_cgrp_subsys
);
4450 if (IS_ERR(cfile_css
))
4452 if (cfile_css
!= css
) {
4457 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
4461 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
4463 spin_lock(&memcg
->event_list_lock
);
4464 list_add(&event
->list
, &memcg
->event_list
);
4465 spin_unlock(&memcg
->event_list_lock
);
4477 eventfd_ctx_put(event
->eventfd
);
4486 static struct cftype mem_cgroup_files
[] = {
4488 .name
= "usage_in_bytes",
4489 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4490 .read_u64
= mem_cgroup_read_u64
,
4493 .name
= "max_usage_in_bytes",
4494 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4495 .write
= mem_cgroup_reset
,
4496 .read_u64
= mem_cgroup_read_u64
,
4499 .name
= "limit_in_bytes",
4500 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4501 .write
= mem_cgroup_write
,
4502 .read_u64
= mem_cgroup_read_u64
,
4505 .name
= "soft_limit_in_bytes",
4506 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4507 .write
= mem_cgroup_write
,
4508 .read_u64
= mem_cgroup_read_u64
,
4512 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4513 .write
= mem_cgroup_reset
,
4514 .read_u64
= mem_cgroup_read_u64
,
4518 .seq_show
= memcg_stat_show
,
4521 .name
= "force_empty",
4522 .write
= mem_cgroup_force_empty_write
,
4525 .name
= "use_hierarchy",
4526 .write_u64
= mem_cgroup_hierarchy_write
,
4527 .read_u64
= mem_cgroup_hierarchy_read
,
4530 .name
= "cgroup.event_control", /* XXX: for compat */
4531 .write
= memcg_write_event_control
,
4532 .flags
= CFTYPE_NO_PREFIX
,
4536 .name
= "swappiness",
4537 .read_u64
= mem_cgroup_swappiness_read
,
4538 .write_u64
= mem_cgroup_swappiness_write
,
4541 .name
= "move_charge_at_immigrate",
4542 .read_u64
= mem_cgroup_move_charge_read
,
4543 .write_u64
= mem_cgroup_move_charge_write
,
4546 .name
= "oom_control",
4547 .seq_show
= mem_cgroup_oom_control_read
,
4548 .write_u64
= mem_cgroup_oom_control_write
,
4549 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4552 .name
= "pressure_level",
4556 .name
= "numa_stat",
4557 .seq_show
= memcg_numa_stat_show
,
4560 #ifdef CONFIG_MEMCG_KMEM
4562 .name
= "kmem.limit_in_bytes",
4563 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4564 .write
= mem_cgroup_write
,
4565 .read_u64
= mem_cgroup_read_u64
,
4568 .name
= "kmem.usage_in_bytes",
4569 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4570 .read_u64
= mem_cgroup_read_u64
,
4573 .name
= "kmem.failcnt",
4574 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
4575 .write
= mem_cgroup_reset
,
4576 .read_u64
= mem_cgroup_read_u64
,
4579 .name
= "kmem.max_usage_in_bytes",
4580 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4581 .write
= mem_cgroup_reset
,
4582 .read_u64
= mem_cgroup_read_u64
,
4584 #ifdef CONFIG_SLABINFO
4586 .name
= "kmem.slabinfo",
4587 .seq_start
= slab_start
,
4588 .seq_next
= slab_next
,
4589 .seq_stop
= slab_stop
,
4590 .seq_show
= memcg_slab_show
,
4594 { }, /* terminate */
4597 #ifdef CONFIG_MEMCG_SWAP
4598 static struct cftype memsw_cgroup_files
[] = {
4600 .name
= "memsw.usage_in_bytes",
4601 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
4602 .read_u64
= mem_cgroup_read_u64
,
4605 .name
= "memsw.max_usage_in_bytes",
4606 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
4607 .write
= mem_cgroup_reset
,
4608 .read_u64
= mem_cgroup_read_u64
,
4611 .name
= "memsw.limit_in_bytes",
4612 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
4613 .write
= mem_cgroup_write
,
4614 .read_u64
= mem_cgroup_read_u64
,
4617 .name
= "memsw.failcnt",
4618 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
4619 .write
= mem_cgroup_reset
,
4620 .read_u64
= mem_cgroup_read_u64
,
4622 { }, /* terminate */
4625 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
4627 struct mem_cgroup_per_node
*pn
;
4628 struct mem_cgroup_per_zone
*mz
;
4629 int zone
, tmp
= node
;
4631 * This routine is called against possible nodes.
4632 * But it's BUG to call kmalloc() against offline node.
4634 * TODO: this routine can waste much memory for nodes which will
4635 * never be onlined. It's better to use memory hotplug callback
4638 if (!node_state(node
, N_NORMAL_MEMORY
))
4640 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4644 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
4645 mz
= &pn
->zoneinfo
[zone
];
4646 lruvec_init(&mz
->lruvec
);
4647 mz
->usage_in_excess
= 0;
4648 mz
->on_tree
= false;
4651 memcg
->nodeinfo
[node
] = pn
;
4655 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
4657 kfree(memcg
->nodeinfo
[node
]);
4660 static struct mem_cgroup
*mem_cgroup_alloc(void)
4662 struct mem_cgroup
*memcg
;
4665 size
= sizeof(struct mem_cgroup
);
4666 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
4668 memcg
= kzalloc(size
, GFP_KERNEL
);
4672 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
4675 spin_lock_init(&memcg
->pcp_counter_lock
);
4684 * At destroying mem_cgroup, references from swap_cgroup can remain.
4685 * (scanning all at force_empty is too costly...)
4687 * Instead of clearing all references at force_empty, we remember
4688 * the number of reference from swap_cgroup and free mem_cgroup when
4689 * it goes down to 0.
4691 * Removal of cgroup itself succeeds regardless of refs from swap.
4694 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
4698 mem_cgroup_remove_from_trees(memcg
);
4701 free_mem_cgroup_per_zone_info(memcg
, node
);
4703 free_percpu(memcg
->stat
);
4705 disarm_static_keys(memcg
);
4710 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4712 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
4714 if (!memcg
->memory
.parent
)
4716 return mem_cgroup_from_counter(memcg
->memory
.parent
, memory
);
4718 EXPORT_SYMBOL(parent_mem_cgroup
);
4720 static void __init
mem_cgroup_soft_limit_tree_init(void)
4722 struct mem_cgroup_tree_per_node
*rtpn
;
4723 struct mem_cgroup_tree_per_zone
*rtpz
;
4724 int tmp
, node
, zone
;
4726 for_each_node(node
) {
4728 if (!node_state(node
, N_NORMAL_MEMORY
))
4730 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
4733 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
4735 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
4736 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
4737 rtpz
->rb_root
= RB_ROOT
;
4738 spin_lock_init(&rtpz
->lock
);
4743 static struct cgroup_subsys_state
* __ref
4744 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
4746 struct mem_cgroup
*memcg
;
4747 long error
= -ENOMEM
;
4750 memcg
= mem_cgroup_alloc();
4752 return ERR_PTR(error
);
4755 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
4759 if (parent_css
== NULL
) {
4760 root_mem_cgroup
= memcg
;
4761 page_counter_init(&memcg
->memory
, NULL
);
4762 page_counter_init(&memcg
->memsw
, NULL
);
4763 page_counter_init(&memcg
->kmem
, NULL
);
4766 memcg
->last_scanned_node
= MAX_NUMNODES
;
4767 INIT_LIST_HEAD(&memcg
->oom_notify
);
4768 memcg
->move_charge_at_immigrate
= 0;
4769 mutex_init(&memcg
->thresholds_lock
);
4770 spin_lock_init(&memcg
->move_lock
);
4771 vmpressure_init(&memcg
->vmpressure
);
4772 INIT_LIST_HEAD(&memcg
->event_list
);
4773 spin_lock_init(&memcg
->event_list_lock
);
4774 #ifdef CONFIG_MEMCG_KMEM
4775 memcg
->kmemcg_id
= -1;
4776 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
4782 __mem_cgroup_free(memcg
);
4783 return ERR_PTR(error
);
4787 mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
4789 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4790 struct mem_cgroup
*parent
= mem_cgroup_from_css(css
->parent
);
4793 if (css
->id
> MEM_CGROUP_ID_MAX
)
4799 mutex_lock(&memcg_create_mutex
);
4801 memcg
->use_hierarchy
= parent
->use_hierarchy
;
4802 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
4803 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
4805 if (parent
->use_hierarchy
) {
4806 page_counter_init(&memcg
->memory
, &parent
->memory
);
4807 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
4808 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
4811 * No need to take a reference to the parent because cgroup
4812 * core guarantees its existence.
4815 page_counter_init(&memcg
->memory
, NULL
);
4816 page_counter_init(&memcg
->memsw
, NULL
);
4817 page_counter_init(&memcg
->kmem
, NULL
);
4819 * Deeper hierachy with use_hierarchy == false doesn't make
4820 * much sense so let cgroup subsystem know about this
4821 * unfortunate state in our controller.
4823 if (parent
!= root_mem_cgroup
)
4824 memory_cgrp_subsys
.broken_hierarchy
= true;
4826 mutex_unlock(&memcg_create_mutex
);
4828 ret
= memcg_init_kmem(memcg
, &memory_cgrp_subsys
);
4833 * Make sure the memcg is initialized: mem_cgroup_iter()
4834 * orders reading memcg->initialized against its callers
4835 * reading the memcg members.
4837 smp_store_release(&memcg
->initialized
, 1);
4842 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
4844 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4845 struct mem_cgroup_event
*event
, *tmp
;
4848 * Unregister events and notify userspace.
4849 * Notify userspace about cgroup removing only after rmdir of cgroup
4850 * directory to avoid race between userspace and kernelspace.
4852 spin_lock(&memcg
->event_list_lock
);
4853 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
4854 list_del_init(&event
->list
);
4855 schedule_work(&event
->remove
);
4857 spin_unlock(&memcg
->event_list_lock
);
4859 memcg_unregister_all_caches(memcg
);
4860 vmpressure_cleanup(&memcg
->vmpressure
);
4863 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
4865 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4867 memcg_destroy_kmem(memcg
);
4868 __mem_cgroup_free(memcg
);
4872 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4873 * @css: the target css
4875 * Reset the states of the mem_cgroup associated with @css. This is
4876 * invoked when the userland requests disabling on the default hierarchy
4877 * but the memcg is pinned through dependency. The memcg should stop
4878 * applying policies and should revert to the vanilla state as it may be
4879 * made visible again.
4881 * The current implementation only resets the essential configurations.
4882 * This needs to be expanded to cover all the visible parts.
4884 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
4886 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4888 mem_cgroup_resize_limit(memcg
, PAGE_COUNTER_MAX
);
4889 mem_cgroup_resize_memsw_limit(memcg
, PAGE_COUNTER_MAX
);
4890 memcg_update_kmem_limit(memcg
, PAGE_COUNTER_MAX
);
4891 memcg
->soft_limit
= 0;
4895 /* Handlers for move charge at task migration. */
4896 static int mem_cgroup_do_precharge(unsigned long count
)
4900 /* Try a single bulk charge without reclaim first */
4901 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_WAIT
, count
);
4903 mc
.precharge
+= count
;
4906 if (ret
== -EINTR
) {
4907 cancel_charge(root_mem_cgroup
, count
);
4911 /* Try charges one by one with reclaim */
4913 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_NORETRY
, 1);
4915 * In case of failure, any residual charges against
4916 * mc.to will be dropped by mem_cgroup_clear_mc()
4917 * later on. However, cancel any charges that are
4918 * bypassed to root right away or they'll be lost.
4921 cancel_charge(root_mem_cgroup
, 1);
4931 * get_mctgt_type - get target type of moving charge
4932 * @vma: the vma the pte to be checked belongs
4933 * @addr: the address corresponding to the pte to be checked
4934 * @ptent: the pte to be checked
4935 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4938 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4939 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4940 * move charge. if @target is not NULL, the page is stored in target->page
4941 * with extra refcnt got(Callers should handle it).
4942 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4943 * target for charge migration. if @target is not NULL, the entry is stored
4946 * Called with pte lock held.
4953 enum mc_target_type
{
4959 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
4960 unsigned long addr
, pte_t ptent
)
4962 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
4964 if (!page
|| !page_mapped(page
))
4966 if (PageAnon(page
)) {
4967 /* we don't move shared anon */
4970 } else if (!move_file())
4971 /* we ignore mapcount for file pages */
4973 if (!get_page_unless_zero(page
))
4980 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4981 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
4983 struct page
*page
= NULL
;
4984 swp_entry_t ent
= pte_to_swp_entry(ptent
);
4986 if (!move_anon() || non_swap_entry(ent
))
4989 * Because lookup_swap_cache() updates some statistics counter,
4990 * we call find_get_page() with swapper_space directly.
4992 page
= find_get_page(swap_address_space(ent
), ent
.val
);
4993 if (do_swap_account
)
4994 entry
->val
= ent
.val
;
4999 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5000 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5006 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5007 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5009 struct page
*page
= NULL
;
5010 struct address_space
*mapping
;
5013 if (!vma
->vm_file
) /* anonymous vma */
5018 mapping
= vma
->vm_file
->f_mapping
;
5019 if (pte_none(ptent
))
5020 pgoff
= linear_page_index(vma
, addr
);
5021 else /* pte_file(ptent) is true */
5022 pgoff
= pte_to_pgoff(ptent
);
5024 /* page is moved even if it's not RSS of this task(page-faulted). */
5026 /* shmem/tmpfs may report page out on swap: account for that too. */
5027 if (shmem_mapping(mapping
)) {
5028 page
= find_get_entry(mapping
, pgoff
);
5029 if (radix_tree_exceptional_entry(page
)) {
5030 swp_entry_t swp
= radix_to_swp_entry(page
);
5031 if (do_swap_account
)
5033 page
= find_get_page(swap_address_space(swp
), swp
.val
);
5036 page
= find_get_page(mapping
, pgoff
);
5038 page
= find_get_page(mapping
, pgoff
);
5043 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5044 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5046 struct page
*page
= NULL
;
5047 enum mc_target_type ret
= MC_TARGET_NONE
;
5048 swp_entry_t ent
= { .val
= 0 };
5050 if (pte_present(ptent
))
5051 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5052 else if (is_swap_pte(ptent
))
5053 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
5054 else if (pte_none(ptent
) || pte_file(ptent
))
5055 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5057 if (!page
&& !ent
.val
)
5061 * Do only loose check w/o serialization.
5062 * mem_cgroup_move_account() checks the page is valid or
5063 * not under LRU exclusion.
5065 if (page
->mem_cgroup
== mc
.from
) {
5066 ret
= MC_TARGET_PAGE
;
5068 target
->page
= page
;
5070 if (!ret
|| !target
)
5073 /* There is a swap entry and a page doesn't exist or isn't charged */
5074 if (ent
.val
&& !ret
&&
5075 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
5076 ret
= MC_TARGET_SWAP
;
5083 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5085 * We don't consider swapping or file mapped pages because THP does not
5086 * support them for now.
5087 * Caller should make sure that pmd_trans_huge(pmd) is true.
5089 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5090 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5092 struct page
*page
= NULL
;
5093 enum mc_target_type ret
= MC_TARGET_NONE
;
5095 page
= pmd_page(pmd
);
5096 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
5099 if (page
->mem_cgroup
== mc
.from
) {
5100 ret
= MC_TARGET_PAGE
;
5103 target
->page
= page
;
5109 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5110 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5112 return MC_TARGET_NONE
;
5116 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5117 unsigned long addr
, unsigned long end
,
5118 struct mm_walk
*walk
)
5120 struct vm_area_struct
*vma
= walk
->private;
5124 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
5125 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5126 mc
.precharge
+= HPAGE_PMD_NR
;
5131 if (pmd_trans_unstable(pmd
))
5133 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5134 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5135 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5136 mc
.precharge
++; /* increment precharge temporarily */
5137 pte_unmap_unlock(pte
- 1, ptl
);
5143 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5145 unsigned long precharge
;
5146 struct vm_area_struct
*vma
;
5148 down_read(&mm
->mmap_sem
);
5149 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
5150 struct mm_walk mem_cgroup_count_precharge_walk
= {
5151 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5155 if (is_vm_hugetlb_page(vma
))
5157 walk_page_range(vma
->vm_start
, vma
->vm_end
,
5158 &mem_cgroup_count_precharge_walk
);
5160 up_read(&mm
->mmap_sem
);
5162 precharge
= mc
.precharge
;
5168 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5170 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5172 VM_BUG_ON(mc
.moving_task
);
5173 mc
.moving_task
= current
;
5174 return mem_cgroup_do_precharge(precharge
);
5177 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5178 static void __mem_cgroup_clear_mc(void)
5180 struct mem_cgroup
*from
= mc
.from
;
5181 struct mem_cgroup
*to
= mc
.to
;
5183 /* we must uncharge all the leftover precharges from mc.to */
5185 cancel_charge(mc
.to
, mc
.precharge
);
5189 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5190 * we must uncharge here.
5192 if (mc
.moved_charge
) {
5193 cancel_charge(mc
.from
, mc
.moved_charge
);
5194 mc
.moved_charge
= 0;
5196 /* we must fixup refcnts and charges */
5197 if (mc
.moved_swap
) {
5198 /* uncharge swap account from the old cgroup */
5199 if (!mem_cgroup_is_root(mc
.from
))
5200 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
5203 * we charged both to->memory and to->memsw, so we
5204 * should uncharge to->memory.
5206 if (!mem_cgroup_is_root(mc
.to
))
5207 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
5209 css_put_many(&mc
.from
->css
, mc
.moved_swap
);
5211 /* we've already done css_get(mc.to) */
5214 memcg_oom_recover(from
);
5215 memcg_oom_recover(to
);
5216 wake_up_all(&mc
.waitq
);
5219 static void mem_cgroup_clear_mc(void)
5222 * we must clear moving_task before waking up waiters at the end of
5225 mc
.moving_task
= NULL
;
5226 __mem_cgroup_clear_mc();
5227 spin_lock(&mc
.lock
);
5230 spin_unlock(&mc
.lock
);
5233 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
5234 struct cgroup_taskset
*tset
)
5236 struct task_struct
*p
= cgroup_taskset_first(tset
);
5238 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5239 unsigned long move_charge_at_immigrate
;
5242 * We are now commited to this value whatever it is. Changes in this
5243 * tunable will only affect upcoming migrations, not the current one.
5244 * So we need to save it, and keep it going.
5246 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
5247 if (move_charge_at_immigrate
) {
5248 struct mm_struct
*mm
;
5249 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
5251 VM_BUG_ON(from
== memcg
);
5253 mm
= get_task_mm(p
);
5256 /* We move charges only when we move a owner of the mm */
5257 if (mm
->owner
== p
) {
5260 VM_BUG_ON(mc
.precharge
);
5261 VM_BUG_ON(mc
.moved_charge
);
5262 VM_BUG_ON(mc
.moved_swap
);
5264 spin_lock(&mc
.lock
);
5267 mc
.immigrate_flags
= move_charge_at_immigrate
;
5268 spin_unlock(&mc
.lock
);
5269 /* We set mc.moving_task later */
5271 ret
= mem_cgroup_precharge_mc(mm
);
5273 mem_cgroup_clear_mc();
5280 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
5281 struct cgroup_taskset
*tset
)
5284 mem_cgroup_clear_mc();
5287 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
5288 unsigned long addr
, unsigned long end
,
5289 struct mm_walk
*walk
)
5292 struct vm_area_struct
*vma
= walk
->private;
5295 enum mc_target_type target_type
;
5296 union mc_target target
;
5300 * We don't take compound_lock() here but no race with splitting thp
5302 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5303 * under splitting, which means there's no concurrent thp split,
5304 * - if another thread runs into split_huge_page() just after we
5305 * entered this if-block, the thread must wait for page table lock
5306 * to be unlocked in __split_huge_page_splitting(), where the main
5307 * part of thp split is not executed yet.
5309 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
5310 if (mc
.precharge
< HPAGE_PMD_NR
) {
5314 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
5315 if (target_type
== MC_TARGET_PAGE
) {
5317 if (!isolate_lru_page(page
)) {
5318 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
5320 mc
.precharge
-= HPAGE_PMD_NR
;
5321 mc
.moved_charge
+= HPAGE_PMD_NR
;
5323 putback_lru_page(page
);
5331 if (pmd_trans_unstable(pmd
))
5334 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5335 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
5336 pte_t ptent
= *(pte
++);
5342 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
5343 case MC_TARGET_PAGE
:
5345 if (isolate_lru_page(page
))
5347 if (!mem_cgroup_move_account(page
, 1, mc
.from
, mc
.to
)) {
5349 /* we uncharge from mc.from later. */
5352 putback_lru_page(page
);
5353 put
: /* get_mctgt_type() gets the page */
5356 case MC_TARGET_SWAP
:
5358 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
5360 /* we fixup refcnts and charges later. */
5368 pte_unmap_unlock(pte
- 1, ptl
);
5373 * We have consumed all precharges we got in can_attach().
5374 * We try charge one by one, but don't do any additional
5375 * charges to mc.to if we have failed in charge once in attach()
5378 ret
= mem_cgroup_do_precharge(1);
5386 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
5388 struct vm_area_struct
*vma
;
5390 lru_add_drain_all();
5392 * Signal mem_cgroup_begin_page_stat() to take the memcg's
5393 * move_lock while we're moving its pages to another memcg.
5394 * Then wait for already started RCU-only updates to finish.
5396 atomic_inc(&mc
.from
->moving_account
);
5399 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
5401 * Someone who are holding the mmap_sem might be waiting in
5402 * waitq. So we cancel all extra charges, wake up all waiters,
5403 * and retry. Because we cancel precharges, we might not be able
5404 * to move enough charges, but moving charge is a best-effort
5405 * feature anyway, so it wouldn't be a big problem.
5407 __mem_cgroup_clear_mc();
5411 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
5413 struct mm_walk mem_cgroup_move_charge_walk
= {
5414 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
5418 if (is_vm_hugetlb_page(vma
))
5420 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
5421 &mem_cgroup_move_charge_walk
);
5424 * means we have consumed all precharges and failed in
5425 * doing additional charge. Just abandon here.
5429 up_read(&mm
->mmap_sem
);
5430 atomic_dec(&mc
.from
->moving_account
);
5433 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
5434 struct cgroup_taskset
*tset
)
5436 struct task_struct
*p
= cgroup_taskset_first(tset
);
5437 struct mm_struct
*mm
= get_task_mm(p
);
5441 mem_cgroup_move_charge(mm
);
5445 mem_cgroup_clear_mc();
5447 #else /* !CONFIG_MMU */
5448 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
5449 struct cgroup_taskset
*tset
)
5453 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
5454 struct cgroup_taskset
*tset
)
5457 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
5458 struct cgroup_taskset
*tset
)
5464 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5465 * to verify whether we're attached to the default hierarchy on each mount
5468 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5471 * use_hierarchy is forced on the default hierarchy. cgroup core
5472 * guarantees that @root doesn't have any children, so turning it
5473 * on for the root memcg is enough.
5475 if (cgroup_on_dfl(root_css
->cgroup
))
5476 mem_cgroup_from_css(root_css
)->use_hierarchy
= true;
5479 struct cgroup_subsys memory_cgrp_subsys
= {
5480 .css_alloc
= mem_cgroup_css_alloc
,
5481 .css_online
= mem_cgroup_css_online
,
5482 .css_offline
= mem_cgroup_css_offline
,
5483 .css_free
= mem_cgroup_css_free
,
5484 .css_reset
= mem_cgroup_css_reset
,
5485 .can_attach
= mem_cgroup_can_attach
,
5486 .cancel_attach
= mem_cgroup_cancel_attach
,
5487 .attach
= mem_cgroup_move_task
,
5488 .bind
= mem_cgroup_bind
,
5489 .legacy_cftypes
= mem_cgroup_files
,
5493 #ifdef CONFIG_MEMCG_SWAP
5494 static int __init
enable_swap_account(char *s
)
5496 if (!strcmp(s
, "1"))
5497 really_do_swap_account
= 1;
5498 else if (!strcmp(s
, "0"))
5499 really_do_swap_account
= 0;
5502 __setup("swapaccount=", enable_swap_account
);
5504 static void __init
memsw_file_init(void)
5506 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
,
5507 memsw_cgroup_files
));
5510 static void __init
enable_swap_cgroup(void)
5512 if (!mem_cgroup_disabled() && really_do_swap_account
) {
5513 do_swap_account
= 1;
5519 static void __init
enable_swap_cgroup(void)
5524 #ifdef CONFIG_MEMCG_SWAP
5526 * mem_cgroup_swapout - transfer a memsw charge to swap
5527 * @page: page whose memsw charge to transfer
5528 * @entry: swap entry to move the charge to
5530 * Transfer the memsw charge of @page to @entry.
5532 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
5534 struct mem_cgroup
*memcg
;
5535 unsigned short oldid
;
5537 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5538 VM_BUG_ON_PAGE(page_count(page
), page
);
5540 if (!do_swap_account
)
5543 memcg
= page
->mem_cgroup
;
5545 /* Readahead page, never charged */
5549 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
));
5550 VM_BUG_ON_PAGE(oldid
, page
);
5551 mem_cgroup_swap_statistics(memcg
, true);
5553 page
->mem_cgroup
= NULL
;
5555 if (!mem_cgroup_is_root(memcg
))
5556 page_counter_uncharge(&memcg
->memory
, 1);
5558 /* XXX: caller holds IRQ-safe mapping->tree_lock */
5559 VM_BUG_ON(!irqs_disabled());
5561 mem_cgroup_charge_statistics(memcg
, page
, -1);
5562 memcg_check_events(memcg
, page
);
5566 * mem_cgroup_uncharge_swap - uncharge a swap entry
5567 * @entry: swap entry to uncharge
5569 * Drop the memsw charge associated with @entry.
5571 void mem_cgroup_uncharge_swap(swp_entry_t entry
)
5573 struct mem_cgroup
*memcg
;
5576 if (!do_swap_account
)
5579 id
= swap_cgroup_record(entry
, 0);
5581 memcg
= mem_cgroup_lookup(id
);
5583 if (!mem_cgroup_is_root(memcg
))
5584 page_counter_uncharge(&memcg
->memsw
, 1);
5585 mem_cgroup_swap_statistics(memcg
, false);
5586 css_put(&memcg
->css
);
5593 * mem_cgroup_try_charge - try charging a page
5594 * @page: page to charge
5595 * @mm: mm context of the victim
5596 * @gfp_mask: reclaim mode
5597 * @memcgp: charged memcg return
5599 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5600 * pages according to @gfp_mask if necessary.
5602 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5603 * Otherwise, an error code is returned.
5605 * After page->mapping has been set up, the caller must finalize the
5606 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5607 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5609 int mem_cgroup_try_charge(struct page
*page
, struct mm_struct
*mm
,
5610 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
5612 struct mem_cgroup
*memcg
= NULL
;
5613 unsigned int nr_pages
= 1;
5616 if (mem_cgroup_disabled())
5619 if (PageSwapCache(page
)) {
5621 * Every swap fault against a single page tries to charge the
5622 * page, bail as early as possible. shmem_unuse() encounters
5623 * already charged pages, too. The USED bit is protected by
5624 * the page lock, which serializes swap cache removal, which
5625 * in turn serializes uncharging.
5627 if (page
->mem_cgroup
)
5631 if (PageTransHuge(page
)) {
5632 nr_pages
<<= compound_order(page
);
5633 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
5636 if (do_swap_account
&& PageSwapCache(page
))
5637 memcg
= try_get_mem_cgroup_from_page(page
);
5639 memcg
= get_mem_cgroup_from_mm(mm
);
5641 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
5643 css_put(&memcg
->css
);
5645 if (ret
== -EINTR
) {
5646 memcg
= root_mem_cgroup
;
5655 * mem_cgroup_commit_charge - commit a page charge
5656 * @page: page to charge
5657 * @memcg: memcg to charge the page to
5658 * @lrucare: page might be on LRU already
5660 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5661 * after page->mapping has been set up. This must happen atomically
5662 * as part of the page instantiation, i.e. under the page table lock
5663 * for anonymous pages, under the page lock for page and swap cache.
5665 * In addition, the page must not be on the LRU during the commit, to
5666 * prevent racing with task migration. If it might be, use @lrucare.
5668 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5670 void mem_cgroup_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5673 unsigned int nr_pages
= 1;
5675 VM_BUG_ON_PAGE(!page
->mapping
, page
);
5676 VM_BUG_ON_PAGE(PageLRU(page
) && !lrucare
, page
);
5678 if (mem_cgroup_disabled())
5681 * Swap faults will attempt to charge the same page multiple
5682 * times. But reuse_swap_page() might have removed the page
5683 * from swapcache already, so we can't check PageSwapCache().
5688 commit_charge(page
, memcg
, lrucare
);
5690 if (PageTransHuge(page
)) {
5691 nr_pages
<<= compound_order(page
);
5692 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
5695 local_irq_disable();
5696 mem_cgroup_charge_statistics(memcg
, page
, nr_pages
);
5697 memcg_check_events(memcg
, page
);
5700 if (do_swap_account
&& PageSwapCache(page
)) {
5701 swp_entry_t entry
= { .val
= page_private(page
) };
5703 * The swap entry might not get freed for a long time,
5704 * let's not wait for it. The page already received a
5705 * memory+swap charge, drop the swap entry duplicate.
5707 mem_cgroup_uncharge_swap(entry
);
5712 * mem_cgroup_cancel_charge - cancel a page charge
5713 * @page: page to charge
5714 * @memcg: memcg to charge the page to
5716 * Cancel a charge transaction started by mem_cgroup_try_charge().
5718 void mem_cgroup_cancel_charge(struct page
*page
, struct mem_cgroup
*memcg
)
5720 unsigned int nr_pages
= 1;
5722 if (mem_cgroup_disabled())
5725 * Swap faults will attempt to charge the same page multiple
5726 * times. But reuse_swap_page() might have removed the page
5727 * from swapcache already, so we can't check PageSwapCache().
5732 if (PageTransHuge(page
)) {
5733 nr_pages
<<= compound_order(page
);
5734 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
5737 cancel_charge(memcg
, nr_pages
);
5740 static void uncharge_batch(struct mem_cgroup
*memcg
, unsigned long pgpgout
,
5741 unsigned long nr_anon
, unsigned long nr_file
,
5742 unsigned long nr_huge
, struct page
*dummy_page
)
5744 unsigned long nr_pages
= nr_anon
+ nr_file
;
5745 unsigned long flags
;
5747 if (!mem_cgroup_is_root(memcg
)) {
5748 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5749 if (do_swap_account
)
5750 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
5751 memcg_oom_recover(memcg
);
5754 local_irq_save(flags
);
5755 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
], nr_anon
);
5756 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
], nr_file
);
5757 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
], nr_huge
);
5758 __this_cpu_add(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
], pgpgout
);
5759 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
5760 memcg_check_events(memcg
, dummy_page
);
5761 local_irq_restore(flags
);
5763 if (!mem_cgroup_is_root(memcg
))
5764 css_put_many(&memcg
->css
, nr_pages
);
5767 static void uncharge_list(struct list_head
*page_list
)
5769 struct mem_cgroup
*memcg
= NULL
;
5770 unsigned long nr_anon
= 0;
5771 unsigned long nr_file
= 0;
5772 unsigned long nr_huge
= 0;
5773 unsigned long pgpgout
= 0;
5774 struct list_head
*next
;
5777 next
= page_list
->next
;
5779 unsigned int nr_pages
= 1;
5781 page
= list_entry(next
, struct page
, lru
);
5782 next
= page
->lru
.next
;
5784 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5785 VM_BUG_ON_PAGE(page_count(page
), page
);
5787 if (!page
->mem_cgroup
)
5791 * Nobody should be changing or seriously looking at
5792 * page->mem_cgroup at this point, we have fully
5793 * exclusive access to the page.
5796 if (memcg
!= page
->mem_cgroup
) {
5798 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5800 pgpgout
= nr_anon
= nr_file
= nr_huge
= 0;
5802 memcg
= page
->mem_cgroup
;
5805 if (PageTransHuge(page
)) {
5806 nr_pages
<<= compound_order(page
);
5807 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
5808 nr_huge
+= nr_pages
;
5812 nr_anon
+= nr_pages
;
5814 nr_file
+= nr_pages
;
5816 page
->mem_cgroup
= NULL
;
5819 } while (next
!= page_list
);
5822 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5827 * mem_cgroup_uncharge - uncharge a page
5828 * @page: page to uncharge
5830 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5831 * mem_cgroup_commit_charge().
5833 void mem_cgroup_uncharge(struct page
*page
)
5835 if (mem_cgroup_disabled())
5838 /* Don't touch page->lru of any random page, pre-check: */
5839 if (!page
->mem_cgroup
)
5842 INIT_LIST_HEAD(&page
->lru
);
5843 uncharge_list(&page
->lru
);
5847 * mem_cgroup_uncharge_list - uncharge a list of page
5848 * @page_list: list of pages to uncharge
5850 * Uncharge a list of pages previously charged with
5851 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5853 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
5855 if (mem_cgroup_disabled())
5858 if (!list_empty(page_list
))
5859 uncharge_list(page_list
);
5863 * mem_cgroup_migrate - migrate a charge to another page
5864 * @oldpage: currently charged page
5865 * @newpage: page to transfer the charge to
5866 * @lrucare: both pages might be on the LRU already
5868 * Migrate the charge from @oldpage to @newpage.
5870 * Both pages must be locked, @newpage->mapping must be set up.
5872 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
,
5875 struct mem_cgroup
*memcg
;
5878 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
5879 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
5880 VM_BUG_ON_PAGE(!lrucare
&& PageLRU(oldpage
), oldpage
);
5881 VM_BUG_ON_PAGE(!lrucare
&& PageLRU(newpage
), newpage
);
5882 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
5883 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
5886 if (mem_cgroup_disabled())
5889 /* Page cache replacement: new page already charged? */
5890 if (newpage
->mem_cgroup
)
5894 * Swapcache readahead pages can get migrated before being
5895 * charged, and migration from compaction can happen to an
5896 * uncharged page when the PFN walker finds a page that
5897 * reclaim just put back on the LRU but has not released yet.
5899 memcg
= oldpage
->mem_cgroup
;
5904 lock_page_lru(oldpage
, &isolated
);
5906 oldpage
->mem_cgroup
= NULL
;
5909 unlock_page_lru(oldpage
, isolated
);
5911 commit_charge(newpage
, memcg
, lrucare
);
5915 * subsys_initcall() for memory controller.
5917 * Some parts like hotcpu_notifier() have to be initialized from this context
5918 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
5919 * everything that doesn't depend on a specific mem_cgroup structure should
5920 * be initialized from here.
5922 static int __init
mem_cgroup_init(void)
5924 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
5925 enable_swap_cgroup();
5926 mem_cgroup_soft_limit_tree_init();
5930 subsys_initcall(mem_cgroup_init
);