1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
28 #include <linux/res_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
32 #include <linux/hugetlb.h>
33 #include <linux/pagemap.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/sort.h>
50 #include <linux/seq_file.h>
51 #include <linux/vmalloc.h>
52 #include <linux/mm_inline.h>
53 #include <linux/page_cgroup.h>
54 #include <linux/cpu.h>
55 #include <linux/oom.h>
59 #include <net/tcp_memcontrol.h>
61 #include <asm/uaccess.h>
63 #include <trace/events/vmscan.h>
65 struct cgroup_subsys mem_cgroup_subsys __read_mostly
;
66 EXPORT_SYMBOL(mem_cgroup_subsys
);
68 #define MEM_CGROUP_RECLAIM_RETRIES 5
69 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
71 #ifdef CONFIG_MEMCG_SWAP
72 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
73 int do_swap_account __read_mostly
;
75 /* for remember boot option*/
76 #ifdef CONFIG_MEMCG_SWAP_ENABLED
77 static int really_do_swap_account __initdata
= 1;
79 static int really_do_swap_account __initdata
= 0;
83 #define do_swap_account 0
88 * Statistics for memory cgroup.
90 enum mem_cgroup_stat_index
{
92 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
94 MEM_CGROUP_STAT_CACHE
, /* # of pages charged as cache */
95 MEM_CGROUP_STAT_RSS
, /* # of pages charged as anon rss */
96 MEM_CGROUP_STAT_FILE_MAPPED
, /* # of pages charged as file rss */
97 MEM_CGROUP_STAT_SWAP
, /* # of pages, swapped out */
98 MEM_CGROUP_STAT_NSTATS
,
101 static const char * const mem_cgroup_stat_names
[] = {
108 enum mem_cgroup_events_index
{
109 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
110 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
111 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
112 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
113 MEM_CGROUP_EVENTS_NSTATS
,
116 static const char * const mem_cgroup_events_names
[] = {
123 static const char * const mem_cgroup_lru_names
[] = {
132 * Per memcg event counter is incremented at every pagein/pageout. With THP,
133 * it will be incremated by the number of pages. This counter is used for
134 * for trigger some periodic events. This is straightforward and better
135 * than using jiffies etc. to handle periodic memcg event.
137 enum mem_cgroup_events_target
{
138 MEM_CGROUP_TARGET_THRESH
,
139 MEM_CGROUP_TARGET_SOFTLIMIT
,
140 MEM_CGROUP_TARGET_NUMAINFO
,
143 #define THRESHOLDS_EVENTS_TARGET 128
144 #define SOFTLIMIT_EVENTS_TARGET 1024
145 #define NUMAINFO_EVENTS_TARGET 1024
147 struct mem_cgroup_stat_cpu
{
148 long count
[MEM_CGROUP_STAT_NSTATS
];
149 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
150 unsigned long nr_page_events
;
151 unsigned long targets
[MEM_CGROUP_NTARGETS
];
154 struct mem_cgroup_reclaim_iter
{
155 /* last scanned hierarchy member with elevated css ref count */
156 struct mem_cgroup
*last_visited
;
157 /* scan generation, increased every round-trip */
158 unsigned int generation
;
159 /* lock to protect the position and generation */
160 spinlock_t iter_lock
;
164 * per-zone information in memory controller.
166 struct mem_cgroup_per_zone
{
167 struct lruvec lruvec
;
168 unsigned long lru_size
[NR_LRU_LISTS
];
170 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
172 struct rb_node tree_node
; /* RB tree node */
173 unsigned long long usage_in_excess
;/* Set to the value by which */
174 /* the soft limit is exceeded*/
176 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
177 /* use container_of */
180 struct mem_cgroup_per_node
{
181 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
184 struct mem_cgroup_lru_info
{
185 struct mem_cgroup_per_node
*nodeinfo
[0];
189 * Cgroups above their limits are maintained in a RB-Tree, independent of
190 * their hierarchy representation
193 struct mem_cgroup_tree_per_zone
{
194 struct rb_root rb_root
;
198 struct mem_cgroup_tree_per_node
{
199 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
202 struct mem_cgroup_tree
{
203 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
206 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
208 struct mem_cgroup_threshold
{
209 struct eventfd_ctx
*eventfd
;
214 struct mem_cgroup_threshold_ary
{
215 /* An array index points to threshold just below or equal to usage. */
216 int current_threshold
;
217 /* Size of entries[] */
219 /* Array of thresholds */
220 struct mem_cgroup_threshold entries
[0];
223 struct mem_cgroup_thresholds
{
224 /* Primary thresholds array */
225 struct mem_cgroup_threshold_ary
*primary
;
227 * Spare threshold array.
228 * This is needed to make mem_cgroup_unregister_event() "never fail".
229 * It must be able to store at least primary->size - 1 entries.
231 struct mem_cgroup_threshold_ary
*spare
;
235 struct mem_cgroup_eventfd_list
{
236 struct list_head list
;
237 struct eventfd_ctx
*eventfd
;
240 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
241 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
244 * The memory controller data structure. The memory controller controls both
245 * page cache and RSS per cgroup. We would eventually like to provide
246 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
247 * to help the administrator determine what knobs to tune.
249 * TODO: Add a water mark for the memory controller. Reclaim will begin when
250 * we hit the water mark. May be even add a low water mark, such that
251 * no reclaim occurs from a cgroup at it's low water mark, this is
252 * a feature that will be implemented much later in the future.
255 struct cgroup_subsys_state css
;
257 * the counter to account for memory usage
259 struct res_counter res
;
263 * the counter to account for mem+swap usage.
265 struct res_counter memsw
;
268 * rcu_freeing is used only when freeing struct mem_cgroup,
269 * so put it into a union to avoid wasting more memory.
270 * It must be disjoint from the css field. It could be
271 * in a union with the res field, but res plays a much
272 * larger part in mem_cgroup life than memsw, and might
273 * be of interest, even at time of free, when debugging.
274 * So share rcu_head with the less interesting memsw.
276 struct rcu_head rcu_freeing
;
278 * We also need some space for a worker in deferred freeing.
279 * By the time we call it, rcu_freeing is no longer in use.
281 struct work_struct work_freeing
;
285 * the counter to account for kernel memory usage.
287 struct res_counter kmem
;
289 * Should the accounting and control be hierarchical, per subtree?
292 unsigned long kmem_account_flags
; /* See KMEM_ACCOUNTED_*, below */
300 /* OOM-Killer disable */
301 int oom_kill_disable
;
303 /* set when res.limit == memsw.limit */
304 bool memsw_is_minimum
;
306 /* protect arrays of thresholds */
307 struct mutex thresholds_lock
;
309 /* thresholds for memory usage. RCU-protected */
310 struct mem_cgroup_thresholds thresholds
;
312 /* thresholds for mem+swap usage. RCU-protected */
313 struct mem_cgroup_thresholds memsw_thresholds
;
315 /* For oom notifier event fd */
316 struct list_head oom_notify
;
319 * Should we move charges of a task when a task is moved into this
320 * mem_cgroup ? And what type of charges should we move ?
322 unsigned long move_charge_at_immigrate
;
324 * set > 0 if pages under this cgroup are moving to other cgroup.
326 atomic_t moving_account
;
327 /* taken only while moving_account > 0 */
328 spinlock_t move_lock
;
332 struct mem_cgroup_stat_cpu __percpu
*stat
;
334 * used when a cpu is offlined or other synchronizations
335 * See mem_cgroup_read_stat().
337 struct mem_cgroup_stat_cpu nocpu_base
;
338 spinlock_t pcp_counter_lock
;
340 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
341 struct tcp_memcontrol tcp_mem
;
343 #if defined(CONFIG_MEMCG_KMEM)
344 /* analogous to slab_common's slab_caches list. per-memcg */
345 struct list_head memcg_slab_caches
;
346 /* Not a spinlock, we can take a lot of time walking the list */
347 struct mutex slab_caches_mutex
;
348 /* Index in the kmem_cache->memcg_params->memcg_caches array */
352 int last_scanned_node
;
354 nodemask_t scan_nodes
;
355 atomic_t numainfo_events
;
356 atomic_t numainfo_updating
;
359 * Per cgroup active and inactive list, similar to the
360 * per zone LRU lists.
362 * WARNING: This has to be the last element of the struct. Don't
363 * add new fields after this point.
365 struct mem_cgroup_lru_info info
;
368 static size_t memcg_size(void)
370 return sizeof(struct mem_cgroup
) +
371 nr_node_ids
* sizeof(struct mem_cgroup_per_node
);
374 /* internal only representation about the status of kmem accounting. */
376 KMEM_ACCOUNTED_ACTIVE
= 0, /* accounted by this cgroup itself */
377 KMEM_ACCOUNTED_ACTIVATED
, /* static key enabled. */
378 KMEM_ACCOUNTED_DEAD
, /* dead memcg with pending kmem charges */
381 /* We account when limit is on, but only after call sites are patched */
382 #define KMEM_ACCOUNTED_MASK \
383 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
385 #ifdef CONFIG_MEMCG_KMEM
386 static inline void memcg_kmem_set_active(struct mem_cgroup
*memcg
)
388 set_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
391 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
393 return test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
396 static void memcg_kmem_set_activated(struct mem_cgroup
*memcg
)
398 set_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
401 static void memcg_kmem_clear_activated(struct mem_cgroup
*memcg
)
403 clear_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
406 static void memcg_kmem_mark_dead(struct mem_cgroup
*memcg
)
408 if (test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
))
409 set_bit(KMEM_ACCOUNTED_DEAD
, &memcg
->kmem_account_flags
);
412 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup
*memcg
)
414 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD
,
415 &memcg
->kmem_account_flags
);
419 /* Stuffs for move charges at task migration. */
421 * Types of charges to be moved. "move_charge_at_immitgrate" and
422 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
425 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
426 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
430 /* "mc" and its members are protected by cgroup_mutex */
431 static struct move_charge_struct
{
432 spinlock_t lock
; /* for from, to */
433 struct mem_cgroup
*from
;
434 struct mem_cgroup
*to
;
435 unsigned long immigrate_flags
;
436 unsigned long precharge
;
437 unsigned long moved_charge
;
438 unsigned long moved_swap
;
439 struct task_struct
*moving_task
; /* a task moving charges */
440 wait_queue_head_t waitq
; /* a waitq for other context */
442 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
443 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
446 static bool move_anon(void)
448 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
451 static bool move_file(void)
453 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
457 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
458 * limit reclaim to prevent infinite loops, if they ever occur.
460 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
461 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
464 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
465 MEM_CGROUP_CHARGE_TYPE_ANON
,
466 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
467 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
471 /* for encoding cft->private value on file */
479 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
480 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
481 #define MEMFILE_ATTR(val) ((val) & 0xffff)
482 /* Used for OOM nofiier */
483 #define OOM_CONTROL (0)
486 * Reclaim flags for mem_cgroup_hierarchical_reclaim
488 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
489 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
490 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
491 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
494 * The memcg_create_mutex will be held whenever a new cgroup is created.
495 * As a consequence, any change that needs to protect against new child cgroups
496 * appearing has to hold it as well.
498 static DEFINE_MUTEX(memcg_create_mutex
);
500 static void mem_cgroup_get(struct mem_cgroup
*memcg
);
501 static void mem_cgroup_put(struct mem_cgroup
*memcg
);
504 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
506 return container_of(s
, struct mem_cgroup
, css
);
509 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
511 return (memcg
== root_mem_cgroup
);
514 /* Writing them here to avoid exposing memcg's inner layout */
515 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
517 void sock_update_memcg(struct sock
*sk
)
519 if (mem_cgroup_sockets_enabled
) {
520 struct mem_cgroup
*memcg
;
521 struct cg_proto
*cg_proto
;
523 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
525 /* Socket cloning can throw us here with sk_cgrp already
526 * filled. It won't however, necessarily happen from
527 * process context. So the test for root memcg given
528 * the current task's memcg won't help us in this case.
530 * Respecting the original socket's memcg is a better
531 * decision in this case.
534 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
535 mem_cgroup_get(sk
->sk_cgrp
->memcg
);
540 memcg
= mem_cgroup_from_task(current
);
541 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
542 if (!mem_cgroup_is_root(memcg
) && memcg_proto_active(cg_proto
)) {
543 mem_cgroup_get(memcg
);
544 sk
->sk_cgrp
= cg_proto
;
549 EXPORT_SYMBOL(sock_update_memcg
);
551 void sock_release_memcg(struct sock
*sk
)
553 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
554 struct mem_cgroup
*memcg
;
555 WARN_ON(!sk
->sk_cgrp
->memcg
);
556 memcg
= sk
->sk_cgrp
->memcg
;
557 mem_cgroup_put(memcg
);
561 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
563 if (!memcg
|| mem_cgroup_is_root(memcg
))
566 return &memcg
->tcp_mem
.cg_proto
;
568 EXPORT_SYMBOL(tcp_proto_cgroup
);
570 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
572 if (!memcg_proto_activated(&memcg
->tcp_mem
.cg_proto
))
574 static_key_slow_dec(&memcg_socket_limit_enabled
);
577 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
582 #ifdef CONFIG_MEMCG_KMEM
584 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
585 * There are two main reasons for not using the css_id for this:
586 * 1) this works better in sparse environments, where we have a lot of memcgs,
587 * but only a few kmem-limited. Or also, if we have, for instance, 200
588 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
589 * 200 entry array for that.
591 * 2) In order not to violate the cgroup API, we would like to do all memory
592 * allocation in ->create(). At that point, we haven't yet allocated the
593 * css_id. Having a separate index prevents us from messing with the cgroup
596 * The current size of the caches array is stored in
597 * memcg_limited_groups_array_size. It will double each time we have to
600 static DEFINE_IDA(kmem_limited_groups
);
601 int memcg_limited_groups_array_size
;
604 * MIN_SIZE is different than 1, because we would like to avoid going through
605 * the alloc/free process all the time. In a small machine, 4 kmem-limited
606 * cgroups is a reasonable guess. In the future, it could be a parameter or
607 * tunable, but that is strictly not necessary.
609 * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get
610 * this constant directly from cgroup, but it is understandable that this is
611 * better kept as an internal representation in cgroup.c. In any case, the
612 * css_id space is not getting any smaller, and we don't have to necessarily
613 * increase ours as well if it increases.
615 #define MEMCG_CACHES_MIN_SIZE 4
616 #define MEMCG_CACHES_MAX_SIZE 65535
619 * A lot of the calls to the cache allocation functions are expected to be
620 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
621 * conditional to this static branch, we'll have to allow modules that does
622 * kmem_cache_alloc and the such to see this symbol as well
624 struct static_key memcg_kmem_enabled_key
;
625 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
627 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
629 if (memcg_kmem_is_active(memcg
)) {
630 static_key_slow_dec(&memcg_kmem_enabled_key
);
631 ida_simple_remove(&kmem_limited_groups
, memcg
->kmemcg_id
);
634 * This check can't live in kmem destruction function,
635 * since the charges will outlive the cgroup
637 WARN_ON(res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0);
640 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
643 #endif /* CONFIG_MEMCG_KMEM */
645 static void disarm_static_keys(struct mem_cgroup
*memcg
)
647 disarm_sock_keys(memcg
);
648 disarm_kmem_keys(memcg
);
651 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
653 static struct mem_cgroup_per_zone
*
654 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
656 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
657 return &memcg
->info
.nodeinfo
[nid
]->zoneinfo
[zid
];
660 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
665 static struct mem_cgroup_per_zone
*
666 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
668 int nid
= page_to_nid(page
);
669 int zid
= page_zonenum(page
);
671 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
674 static struct mem_cgroup_tree_per_zone
*
675 soft_limit_tree_node_zone(int nid
, int zid
)
677 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
680 static struct mem_cgroup_tree_per_zone
*
681 soft_limit_tree_from_page(struct page
*page
)
683 int nid
= page_to_nid(page
);
684 int zid
= page_zonenum(page
);
686 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
690 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
691 struct mem_cgroup_per_zone
*mz
,
692 struct mem_cgroup_tree_per_zone
*mctz
,
693 unsigned long long new_usage_in_excess
)
695 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
696 struct rb_node
*parent
= NULL
;
697 struct mem_cgroup_per_zone
*mz_node
;
702 mz
->usage_in_excess
= new_usage_in_excess
;
703 if (!mz
->usage_in_excess
)
707 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
709 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
712 * We can't avoid mem cgroups that are over their soft
713 * limit by the same amount
715 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
718 rb_link_node(&mz
->tree_node
, parent
, p
);
719 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
724 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
725 struct mem_cgroup_per_zone
*mz
,
726 struct mem_cgroup_tree_per_zone
*mctz
)
730 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
735 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
736 struct mem_cgroup_per_zone
*mz
,
737 struct mem_cgroup_tree_per_zone
*mctz
)
739 spin_lock(&mctz
->lock
);
740 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
741 spin_unlock(&mctz
->lock
);
745 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
747 unsigned long long excess
;
748 struct mem_cgroup_per_zone
*mz
;
749 struct mem_cgroup_tree_per_zone
*mctz
;
750 int nid
= page_to_nid(page
);
751 int zid
= page_zonenum(page
);
752 mctz
= soft_limit_tree_from_page(page
);
755 * Necessary to update all ancestors when hierarchy is used.
756 * because their event counter is not touched.
758 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
759 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
760 excess
= res_counter_soft_limit_excess(&memcg
->res
);
762 * We have to update the tree if mz is on RB-tree or
763 * mem is over its softlimit.
765 if (excess
|| mz
->on_tree
) {
766 spin_lock(&mctz
->lock
);
767 /* if on-tree, remove it */
769 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
771 * Insert again. mz->usage_in_excess will be updated.
772 * If excess is 0, no tree ops.
774 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
775 spin_unlock(&mctz
->lock
);
780 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
783 struct mem_cgroup_per_zone
*mz
;
784 struct mem_cgroup_tree_per_zone
*mctz
;
786 for_each_node(node
) {
787 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
788 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
789 mctz
= soft_limit_tree_node_zone(node
, zone
);
790 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
795 static struct mem_cgroup_per_zone
*
796 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
798 struct rb_node
*rightmost
= NULL
;
799 struct mem_cgroup_per_zone
*mz
;
803 rightmost
= rb_last(&mctz
->rb_root
);
805 goto done
; /* Nothing to reclaim from */
807 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
809 * Remove the node now but someone else can add it back,
810 * we will to add it back at the end of reclaim to its correct
811 * position in the tree.
813 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
814 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
815 !css_tryget(&mz
->memcg
->css
))
821 static struct mem_cgroup_per_zone
*
822 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
824 struct mem_cgroup_per_zone
*mz
;
826 spin_lock(&mctz
->lock
);
827 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
828 spin_unlock(&mctz
->lock
);
833 * Implementation Note: reading percpu statistics for memcg.
835 * Both of vmstat[] and percpu_counter has threshold and do periodic
836 * synchronization to implement "quick" read. There are trade-off between
837 * reading cost and precision of value. Then, we may have a chance to implement
838 * a periodic synchronizion of counter in memcg's counter.
840 * But this _read() function is used for user interface now. The user accounts
841 * memory usage by memory cgroup and he _always_ requires exact value because
842 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
843 * have to visit all online cpus and make sum. So, for now, unnecessary
844 * synchronization is not implemented. (just implemented for cpu hotplug)
846 * If there are kernel internal actions which can make use of some not-exact
847 * value, and reading all cpu value can be performance bottleneck in some
848 * common workload, threashold and synchonization as vmstat[] should be
851 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
852 enum mem_cgroup_stat_index idx
)
858 for_each_online_cpu(cpu
)
859 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
860 #ifdef CONFIG_HOTPLUG_CPU
861 spin_lock(&memcg
->pcp_counter_lock
);
862 val
+= memcg
->nocpu_base
.count
[idx
];
863 spin_unlock(&memcg
->pcp_counter_lock
);
869 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
872 int val
= (charge
) ? 1 : -1;
873 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
876 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
877 enum mem_cgroup_events_index idx
)
879 unsigned long val
= 0;
882 for_each_online_cpu(cpu
)
883 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
884 #ifdef CONFIG_HOTPLUG_CPU
885 spin_lock(&memcg
->pcp_counter_lock
);
886 val
+= memcg
->nocpu_base
.events
[idx
];
887 spin_unlock(&memcg
->pcp_counter_lock
);
892 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
893 bool anon
, int nr_pages
)
898 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
899 * counted as CACHE even if it's on ANON LRU.
902 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
905 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
908 /* pagein of a big page is an event. So, ignore page size */
910 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
912 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
913 nr_pages
= -nr_pages
; /* for event */
916 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
922 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
924 struct mem_cgroup_per_zone
*mz
;
926 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
927 return mz
->lru_size
[lru
];
931 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
932 unsigned int lru_mask
)
934 struct mem_cgroup_per_zone
*mz
;
936 unsigned long ret
= 0;
938 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
941 if (BIT(lru
) & lru_mask
)
942 ret
+= mz
->lru_size
[lru
];
948 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
949 int nid
, unsigned int lru_mask
)
954 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
955 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
961 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
962 unsigned int lru_mask
)
967 for_each_node_state(nid
, N_MEMORY
)
968 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
972 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
973 enum mem_cgroup_events_target target
)
975 unsigned long val
, next
;
977 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
978 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
979 /* from time_after() in jiffies.h */
980 if ((long)next
- (long)val
< 0) {
982 case MEM_CGROUP_TARGET_THRESH
:
983 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
985 case MEM_CGROUP_TARGET_SOFTLIMIT
:
986 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
988 case MEM_CGROUP_TARGET_NUMAINFO
:
989 next
= val
+ NUMAINFO_EVENTS_TARGET
;
994 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
1001 * Check events in order.
1004 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
1007 /* threshold event is triggered in finer grain than soft limit */
1008 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1009 MEM_CGROUP_TARGET_THRESH
))) {
1011 bool do_numainfo __maybe_unused
;
1013 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1014 MEM_CGROUP_TARGET_SOFTLIMIT
);
1015 #if MAX_NUMNODES > 1
1016 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1017 MEM_CGROUP_TARGET_NUMAINFO
);
1021 mem_cgroup_threshold(memcg
);
1022 if (unlikely(do_softlimit
))
1023 mem_cgroup_update_tree(memcg
, page
);
1024 #if MAX_NUMNODES > 1
1025 if (unlikely(do_numainfo
))
1026 atomic_inc(&memcg
->numainfo_events
);
1032 struct mem_cgroup
*mem_cgroup_from_cont(struct cgroup
*cont
)
1034 return mem_cgroup_from_css(
1035 cgroup_subsys_state(cont
, mem_cgroup_subsys_id
));
1038 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1041 * mm_update_next_owner() may clear mm->owner to NULL
1042 * if it races with swapoff, page migration, etc.
1043 * So this can be called with p == NULL.
1048 return mem_cgroup_from_css(task_subsys_state(p
, mem_cgroup_subsys_id
));
1051 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1053 struct mem_cgroup
*memcg
= NULL
;
1058 * Because we have no locks, mm->owner's may be being moved to other
1059 * cgroup. We use css_tryget() here even if this looks
1060 * pessimistic (rather than adding locks here).
1064 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1065 if (unlikely(!memcg
))
1067 } while (!css_tryget(&memcg
->css
));
1073 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1074 * @root: hierarchy root
1075 * @prev: previously returned memcg, NULL on first invocation
1076 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1078 * Returns references to children of the hierarchy below @root, or
1079 * @root itself, or %NULL after a full round-trip.
1081 * Caller must pass the return value in @prev on subsequent
1082 * invocations for reference counting, or use mem_cgroup_iter_break()
1083 * to cancel a hierarchy walk before the round-trip is complete.
1085 * Reclaimers can specify a zone and a priority level in @reclaim to
1086 * divide up the memcgs in the hierarchy among all concurrent
1087 * reclaimers operating on the same zone and priority.
1089 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1090 struct mem_cgroup
*prev
,
1091 struct mem_cgroup_reclaim_cookie
*reclaim
)
1093 struct mem_cgroup
*memcg
= NULL
;
1094 struct mem_cgroup
*last_visited
= NULL
;
1096 if (mem_cgroup_disabled())
1100 root
= root_mem_cgroup
;
1102 if (prev
&& !reclaim
)
1103 last_visited
= prev
;
1105 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1113 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1114 struct cgroup_subsys_state
*css
= NULL
;
1117 int nid
= zone_to_nid(reclaim
->zone
);
1118 int zid
= zone_idx(reclaim
->zone
);
1119 struct mem_cgroup_per_zone
*mz
;
1121 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1122 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1123 spin_lock(&iter
->iter_lock
);
1124 last_visited
= iter
->last_visited
;
1125 if (prev
&& reclaim
->generation
!= iter
->generation
) {
1127 css_put(&last_visited
->css
);
1128 iter
->last_visited
= NULL
;
1130 spin_unlock(&iter
->iter_lock
);
1136 * Root is not visited by cgroup iterators so it needs an
1139 if (!last_visited
) {
1142 struct cgroup
*prev_cgroup
, *next_cgroup
;
1144 prev_cgroup
= (last_visited
== root
) ? NULL
1145 : last_visited
->css
.cgroup
;
1146 next_cgroup
= cgroup_next_descendant_pre(prev_cgroup
,
1149 css
= cgroup_subsys_state(next_cgroup
,
1150 mem_cgroup_subsys_id
);
1154 * Even if we found a group we have to make sure it is alive.
1155 * css && !memcg means that the groups should be skipped and
1156 * we should continue the tree walk.
1157 * last_visited css is safe to use because it is protected by
1158 * css_get and the tree walk is rcu safe.
1160 if (css
== &root
->css
|| (css
&& css_tryget(css
)))
1161 memcg
= mem_cgroup_from_css(css
);
1164 struct mem_cgroup
*curr
= memcg
;
1167 css_put(&last_visited
->css
);
1170 curr
= mem_cgroup_from_css(css
);
1172 /* make sure that the cached memcg is not removed */
1174 css_get(&curr
->css
);
1175 iter
->last_visited
= curr
;
1179 else if (!prev
&& memcg
)
1180 reclaim
->generation
= iter
->generation
;
1181 spin_unlock(&iter
->iter_lock
);
1182 } else if (css
&& !memcg
) {
1183 last_visited
= mem_cgroup_from_css(css
);
1192 if (prev
&& prev
!= root
)
1193 css_put(&prev
->css
);
1199 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1200 * @root: hierarchy root
1201 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1203 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1204 struct mem_cgroup
*prev
)
1207 root
= root_mem_cgroup
;
1208 if (prev
&& prev
!= root
)
1209 css_put(&prev
->css
);
1213 * Iteration constructs for visiting all cgroups (under a tree). If
1214 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1215 * be used for reference counting.
1217 #define for_each_mem_cgroup_tree(iter, root) \
1218 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1220 iter = mem_cgroup_iter(root, iter, NULL))
1222 #define for_each_mem_cgroup(iter) \
1223 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1225 iter = mem_cgroup_iter(NULL, iter, NULL))
1227 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1229 struct mem_cgroup
*memcg
;
1232 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1233 if (unlikely(!memcg
))
1238 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1241 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1249 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1252 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1253 * @zone: zone of the wanted lruvec
1254 * @memcg: memcg of the wanted lruvec
1256 * Returns the lru list vector holding pages for the given @zone and
1257 * @mem. This can be the global zone lruvec, if the memory controller
1260 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1261 struct mem_cgroup
*memcg
)
1263 struct mem_cgroup_per_zone
*mz
;
1264 struct lruvec
*lruvec
;
1266 if (mem_cgroup_disabled()) {
1267 lruvec
= &zone
->lruvec
;
1271 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1272 lruvec
= &mz
->lruvec
;
1275 * Since a node can be onlined after the mem_cgroup was created,
1276 * we have to be prepared to initialize lruvec->zone here;
1277 * and if offlined then reonlined, we need to reinitialize it.
1279 if (unlikely(lruvec
->zone
!= zone
))
1280 lruvec
->zone
= zone
;
1285 * Following LRU functions are allowed to be used without PCG_LOCK.
1286 * Operations are called by routine of global LRU independently from memcg.
1287 * What we have to take care of here is validness of pc->mem_cgroup.
1289 * Changes to pc->mem_cgroup happens when
1292 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1293 * It is added to LRU before charge.
1294 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1295 * When moving account, the page is not on LRU. It's isolated.
1299 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1301 * @zone: zone of the page
1303 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1305 struct mem_cgroup_per_zone
*mz
;
1306 struct mem_cgroup
*memcg
;
1307 struct page_cgroup
*pc
;
1308 struct lruvec
*lruvec
;
1310 if (mem_cgroup_disabled()) {
1311 lruvec
= &zone
->lruvec
;
1315 pc
= lookup_page_cgroup(page
);
1316 memcg
= pc
->mem_cgroup
;
1319 * Surreptitiously switch any uncharged offlist page to root:
1320 * an uncharged page off lru does nothing to secure
1321 * its former mem_cgroup from sudden removal.
1323 * Our caller holds lru_lock, and PageCgroupUsed is updated
1324 * under page_cgroup lock: between them, they make all uses
1325 * of pc->mem_cgroup safe.
1327 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1328 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1330 mz
= page_cgroup_zoneinfo(memcg
, page
);
1331 lruvec
= &mz
->lruvec
;
1334 * Since a node can be onlined after the mem_cgroup was created,
1335 * we have to be prepared to initialize lruvec->zone here;
1336 * and if offlined then reonlined, we need to reinitialize it.
1338 if (unlikely(lruvec
->zone
!= zone
))
1339 lruvec
->zone
= zone
;
1344 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1345 * @lruvec: mem_cgroup per zone lru vector
1346 * @lru: index of lru list the page is sitting on
1347 * @nr_pages: positive when adding or negative when removing
1349 * This function must be called when a page is added to or removed from an
1352 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1355 struct mem_cgroup_per_zone
*mz
;
1356 unsigned long *lru_size
;
1358 if (mem_cgroup_disabled())
1361 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1362 lru_size
= mz
->lru_size
+ lru
;
1363 *lru_size
+= nr_pages
;
1364 VM_BUG_ON((long)(*lru_size
) < 0);
1368 * Checks whether given mem is same or in the root_mem_cgroup's
1371 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1372 struct mem_cgroup
*memcg
)
1374 if (root_memcg
== memcg
)
1376 if (!root_memcg
->use_hierarchy
|| !memcg
)
1378 return css_is_ancestor(&memcg
->css
, &root_memcg
->css
);
1381 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1382 struct mem_cgroup
*memcg
)
1387 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1392 int task_in_mem_cgroup(struct task_struct
*task
, const struct mem_cgroup
*memcg
)
1395 struct mem_cgroup
*curr
= NULL
;
1396 struct task_struct
*p
;
1398 p
= find_lock_task_mm(task
);
1400 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1404 * All threads may have already detached their mm's, but the oom
1405 * killer still needs to detect if they have already been oom
1406 * killed to prevent needlessly killing additional tasks.
1409 curr
= mem_cgroup_from_task(task
);
1411 css_get(&curr
->css
);
1417 * We should check use_hierarchy of "memcg" not "curr". Because checking
1418 * use_hierarchy of "curr" here make this function true if hierarchy is
1419 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1420 * hierarchy(even if use_hierarchy is disabled in "memcg").
1422 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1423 css_put(&curr
->css
);
1427 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1429 unsigned long inactive_ratio
;
1430 unsigned long inactive
;
1431 unsigned long active
;
1434 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1435 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1437 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1439 inactive_ratio
= int_sqrt(10 * gb
);
1443 return inactive
* inactive_ratio
< active
;
1446 #define mem_cgroup_from_res_counter(counter, member) \
1447 container_of(counter, struct mem_cgroup, member)
1450 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1451 * @memcg: the memory cgroup
1453 * Returns the maximum amount of memory @mem can be charged with, in
1456 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1458 unsigned long long margin
;
1460 margin
= res_counter_margin(&memcg
->res
);
1461 if (do_swap_account
)
1462 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1463 return margin
>> PAGE_SHIFT
;
1466 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1468 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
1471 if (cgrp
->parent
== NULL
)
1472 return vm_swappiness
;
1474 return memcg
->swappiness
;
1478 * memcg->moving_account is used for checking possibility that some thread is
1479 * calling move_account(). When a thread on CPU-A starts moving pages under
1480 * a memcg, other threads should check memcg->moving_account under
1481 * rcu_read_lock(), like this:
1485 * memcg->moving_account+1 if (memcg->mocing_account)
1487 * synchronize_rcu() update something.
1492 /* for quick checking without looking up memcg */
1493 atomic_t memcg_moving __read_mostly
;
1495 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1497 atomic_inc(&memcg_moving
);
1498 atomic_inc(&memcg
->moving_account
);
1502 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1505 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1506 * We check NULL in callee rather than caller.
1509 atomic_dec(&memcg_moving
);
1510 atomic_dec(&memcg
->moving_account
);
1515 * 2 routines for checking "mem" is under move_account() or not.
1517 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1518 * is used for avoiding races in accounting. If true,
1519 * pc->mem_cgroup may be overwritten.
1521 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1522 * under hierarchy of moving cgroups. This is for
1523 * waiting at hith-memory prressure caused by "move".
1526 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1528 VM_BUG_ON(!rcu_read_lock_held());
1529 return atomic_read(&memcg
->moving_account
) > 0;
1532 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1534 struct mem_cgroup
*from
;
1535 struct mem_cgroup
*to
;
1538 * Unlike task_move routines, we access mc.to, mc.from not under
1539 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1541 spin_lock(&mc
.lock
);
1547 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1548 || mem_cgroup_same_or_subtree(memcg
, to
);
1550 spin_unlock(&mc
.lock
);
1554 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1556 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1557 if (mem_cgroup_under_move(memcg
)) {
1559 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1560 /* moving charge context might have finished. */
1563 finish_wait(&mc
.waitq
, &wait
);
1571 * Take this lock when
1572 * - a code tries to modify page's memcg while it's USED.
1573 * - a code tries to modify page state accounting in a memcg.
1574 * see mem_cgroup_stolen(), too.
1576 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1577 unsigned long *flags
)
1579 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1582 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1583 unsigned long *flags
)
1585 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1588 #define K(x) ((x) << (PAGE_SHIFT-10))
1590 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1591 * @memcg: The memory cgroup that went over limit
1592 * @p: Task that is going to be killed
1594 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1597 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1599 struct cgroup
*task_cgrp
;
1600 struct cgroup
*mem_cgrp
;
1602 * Need a buffer in BSS, can't rely on allocations. The code relies
1603 * on the assumption that OOM is serialized for memory controller.
1604 * If this assumption is broken, revisit this code.
1606 static char memcg_name
[PATH_MAX
];
1608 struct mem_cgroup
*iter
;
1616 mem_cgrp
= memcg
->css
.cgroup
;
1617 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1619 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1622 * Unfortunately, we are unable to convert to a useful name
1623 * But we'll still print out the usage information
1630 pr_info("Task in %s killed", memcg_name
);
1633 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1641 * Continues from above, so we don't need an KERN_ level
1643 pr_cont(" as a result of limit of %s\n", memcg_name
);
1646 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1647 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1648 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1649 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1650 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1651 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1652 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1653 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1654 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1655 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1656 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1657 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1659 for_each_mem_cgroup_tree(iter
, memcg
) {
1660 pr_info("Memory cgroup stats");
1663 ret
= cgroup_path(iter
->css
.cgroup
, memcg_name
, PATH_MAX
);
1665 pr_cont(" for %s", memcg_name
);
1669 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1670 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1672 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1673 K(mem_cgroup_read_stat(iter
, i
)));
1676 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1677 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1678 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1685 * This function returns the number of memcg under hierarchy tree. Returns
1686 * 1(self count) if no children.
1688 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1691 struct mem_cgroup
*iter
;
1693 for_each_mem_cgroup_tree(iter
, memcg
)
1699 * Return the memory (and swap, if configured) limit for a memcg.
1701 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1705 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1708 * Do not consider swap space if we cannot swap due to swappiness
1710 if (mem_cgroup_swappiness(memcg
)) {
1713 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1714 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1717 * If memsw is finite and limits the amount of swap space
1718 * available to this memcg, return that limit.
1720 limit
= min(limit
, memsw
);
1726 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1729 struct mem_cgroup
*iter
;
1730 unsigned long chosen_points
= 0;
1731 unsigned long totalpages
;
1732 unsigned int points
= 0;
1733 struct task_struct
*chosen
= NULL
;
1736 * If current has a pending SIGKILL, then automatically select it. The
1737 * goal is to allow it to allocate so that it may quickly exit and free
1740 if (fatal_signal_pending(current
)) {
1741 set_thread_flag(TIF_MEMDIE
);
1745 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1746 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1747 for_each_mem_cgroup_tree(iter
, memcg
) {
1748 struct cgroup
*cgroup
= iter
->css
.cgroup
;
1749 struct cgroup_iter it
;
1750 struct task_struct
*task
;
1752 cgroup_iter_start(cgroup
, &it
);
1753 while ((task
= cgroup_iter_next(cgroup
, &it
))) {
1754 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1756 case OOM_SCAN_SELECT
:
1758 put_task_struct(chosen
);
1760 chosen_points
= ULONG_MAX
;
1761 get_task_struct(chosen
);
1763 case OOM_SCAN_CONTINUE
:
1765 case OOM_SCAN_ABORT
:
1766 cgroup_iter_end(cgroup
, &it
);
1767 mem_cgroup_iter_break(memcg
, iter
);
1769 put_task_struct(chosen
);
1774 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1775 if (points
> chosen_points
) {
1777 put_task_struct(chosen
);
1779 chosen_points
= points
;
1780 get_task_struct(chosen
);
1783 cgroup_iter_end(cgroup
, &it
);
1788 points
= chosen_points
* 1000 / totalpages
;
1789 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1790 NULL
, "Memory cgroup out of memory");
1793 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1795 unsigned long flags
)
1797 unsigned long total
= 0;
1798 bool noswap
= false;
1801 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1803 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1806 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1808 drain_all_stock_async(memcg
);
1809 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1811 * Allow limit shrinkers, which are triggered directly
1812 * by userspace, to catch signals and stop reclaim
1813 * after minimal progress, regardless of the margin.
1815 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1817 if (mem_cgroup_margin(memcg
))
1820 * If nothing was reclaimed after two attempts, there
1821 * may be no reclaimable pages in this hierarchy.
1830 * test_mem_cgroup_node_reclaimable
1831 * @memcg: the target memcg
1832 * @nid: the node ID to be checked.
1833 * @noswap : specify true here if the user wants flle only information.
1835 * This function returns whether the specified memcg contains any
1836 * reclaimable pages on a node. Returns true if there are any reclaimable
1837 * pages in the node.
1839 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1840 int nid
, bool noswap
)
1842 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1844 if (noswap
|| !total_swap_pages
)
1846 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1851 #if MAX_NUMNODES > 1
1854 * Always updating the nodemask is not very good - even if we have an empty
1855 * list or the wrong list here, we can start from some node and traverse all
1856 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1859 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1863 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1864 * pagein/pageout changes since the last update.
1866 if (!atomic_read(&memcg
->numainfo_events
))
1868 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1871 /* make a nodemask where this memcg uses memory from */
1872 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1874 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1876 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1877 node_clear(nid
, memcg
->scan_nodes
);
1880 atomic_set(&memcg
->numainfo_events
, 0);
1881 atomic_set(&memcg
->numainfo_updating
, 0);
1885 * Selecting a node where we start reclaim from. Because what we need is just
1886 * reducing usage counter, start from anywhere is O,K. Considering
1887 * memory reclaim from current node, there are pros. and cons.
1889 * Freeing memory from current node means freeing memory from a node which
1890 * we'll use or we've used. So, it may make LRU bad. And if several threads
1891 * hit limits, it will see a contention on a node. But freeing from remote
1892 * node means more costs for memory reclaim because of memory latency.
1894 * Now, we use round-robin. Better algorithm is welcomed.
1896 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1900 mem_cgroup_may_update_nodemask(memcg
);
1901 node
= memcg
->last_scanned_node
;
1903 node
= next_node(node
, memcg
->scan_nodes
);
1904 if (node
== MAX_NUMNODES
)
1905 node
= first_node(memcg
->scan_nodes
);
1907 * We call this when we hit limit, not when pages are added to LRU.
1908 * No LRU may hold pages because all pages are UNEVICTABLE or
1909 * memcg is too small and all pages are not on LRU. In that case,
1910 * we use curret node.
1912 if (unlikely(node
== MAX_NUMNODES
))
1913 node
= numa_node_id();
1915 memcg
->last_scanned_node
= node
;
1920 * Check all nodes whether it contains reclaimable pages or not.
1921 * For quick scan, we make use of scan_nodes. This will allow us to skip
1922 * unused nodes. But scan_nodes is lazily updated and may not cotain
1923 * enough new information. We need to do double check.
1925 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1930 * quick check...making use of scan_node.
1931 * We can skip unused nodes.
1933 if (!nodes_empty(memcg
->scan_nodes
)) {
1934 for (nid
= first_node(memcg
->scan_nodes
);
1936 nid
= next_node(nid
, memcg
->scan_nodes
)) {
1938 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1943 * Check rest of nodes.
1945 for_each_node_state(nid
, N_MEMORY
) {
1946 if (node_isset(nid
, memcg
->scan_nodes
))
1948 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1955 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1960 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1962 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
1966 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1969 unsigned long *total_scanned
)
1971 struct mem_cgroup
*victim
= NULL
;
1974 unsigned long excess
;
1975 unsigned long nr_scanned
;
1976 struct mem_cgroup_reclaim_cookie reclaim
= {
1981 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
1984 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1989 * If we have not been able to reclaim
1990 * anything, it might because there are
1991 * no reclaimable pages under this hierarchy
1996 * We want to do more targeted reclaim.
1997 * excess >> 2 is not to excessive so as to
1998 * reclaim too much, nor too less that we keep
1999 * coming back to reclaim from this cgroup
2001 if (total
>= (excess
>> 2) ||
2002 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
2007 if (!mem_cgroup_reclaimable(victim
, false))
2009 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
2011 *total_scanned
+= nr_scanned
;
2012 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
2015 mem_cgroup_iter_break(root_memcg
, victim
);
2020 * Check OOM-Killer is already running under our hierarchy.
2021 * If someone is running, return false.
2022 * Has to be called with memcg_oom_lock
2024 static bool mem_cgroup_oom_lock(struct mem_cgroup
*memcg
)
2026 struct mem_cgroup
*iter
, *failed
= NULL
;
2028 for_each_mem_cgroup_tree(iter
, memcg
) {
2029 if (iter
->oom_lock
) {
2031 * this subtree of our hierarchy is already locked
2032 * so we cannot give a lock.
2035 mem_cgroup_iter_break(memcg
, iter
);
2038 iter
->oom_lock
= true;
2045 * OK, we failed to lock the whole subtree so we have to clean up
2046 * what we set up to the failing subtree
2048 for_each_mem_cgroup_tree(iter
, memcg
) {
2049 if (iter
== failed
) {
2050 mem_cgroup_iter_break(memcg
, iter
);
2053 iter
->oom_lock
= false;
2059 * Has to be called with memcg_oom_lock
2061 static int mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2063 struct mem_cgroup
*iter
;
2065 for_each_mem_cgroup_tree(iter
, memcg
)
2066 iter
->oom_lock
= false;
2070 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2072 struct mem_cgroup
*iter
;
2074 for_each_mem_cgroup_tree(iter
, memcg
)
2075 atomic_inc(&iter
->under_oom
);
2078 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2080 struct mem_cgroup
*iter
;
2083 * When a new child is created while the hierarchy is under oom,
2084 * mem_cgroup_oom_lock() may not be called. We have to use
2085 * atomic_add_unless() here.
2087 for_each_mem_cgroup_tree(iter
, memcg
)
2088 atomic_add_unless(&iter
->under_oom
, -1, 0);
2091 static DEFINE_SPINLOCK(memcg_oom_lock
);
2092 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2094 struct oom_wait_info
{
2095 struct mem_cgroup
*memcg
;
2099 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2100 unsigned mode
, int sync
, void *arg
)
2102 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2103 struct mem_cgroup
*oom_wait_memcg
;
2104 struct oom_wait_info
*oom_wait_info
;
2106 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2107 oom_wait_memcg
= oom_wait_info
->memcg
;
2110 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2111 * Then we can use css_is_ancestor without taking care of RCU.
2113 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2114 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2116 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2119 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2121 /* for filtering, pass "memcg" as argument. */
2122 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2125 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2127 if (memcg
&& atomic_read(&memcg
->under_oom
))
2128 memcg_wakeup_oom(memcg
);
2132 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
2134 static bool mem_cgroup_handle_oom(struct mem_cgroup
*memcg
, gfp_t mask
,
2137 struct oom_wait_info owait
;
2138 bool locked
, need_to_kill
;
2140 owait
.memcg
= memcg
;
2141 owait
.wait
.flags
= 0;
2142 owait
.wait
.func
= memcg_oom_wake_function
;
2143 owait
.wait
.private = current
;
2144 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2145 need_to_kill
= true;
2146 mem_cgroup_mark_under_oom(memcg
);
2148 /* At first, try to OOM lock hierarchy under memcg.*/
2149 spin_lock(&memcg_oom_lock
);
2150 locked
= mem_cgroup_oom_lock(memcg
);
2152 * Even if signal_pending(), we can't quit charge() loop without
2153 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
2154 * under OOM is always welcomed, use TASK_KILLABLE here.
2156 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2157 if (!locked
|| memcg
->oom_kill_disable
)
2158 need_to_kill
= false;
2160 mem_cgroup_oom_notify(memcg
);
2161 spin_unlock(&memcg_oom_lock
);
2164 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2165 mem_cgroup_out_of_memory(memcg
, mask
, order
);
2168 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2170 spin_lock(&memcg_oom_lock
);
2172 mem_cgroup_oom_unlock(memcg
);
2173 memcg_wakeup_oom(memcg
);
2174 spin_unlock(&memcg_oom_lock
);
2176 mem_cgroup_unmark_under_oom(memcg
);
2178 if (test_thread_flag(TIF_MEMDIE
) || fatal_signal_pending(current
))
2180 /* Give chance to dying process */
2181 schedule_timeout_uninterruptible(1);
2186 * Currently used to update mapped file statistics, but the routine can be
2187 * generalized to update other statistics as well.
2189 * Notes: Race condition
2191 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2192 * it tends to be costly. But considering some conditions, we doesn't need
2193 * to do so _always_.
2195 * Considering "charge", lock_page_cgroup() is not required because all
2196 * file-stat operations happen after a page is attached to radix-tree. There
2197 * are no race with "charge".
2199 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2200 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2201 * if there are race with "uncharge". Statistics itself is properly handled
2204 * Considering "move", this is an only case we see a race. To make the race
2205 * small, we check mm->moving_account and detect there are possibility of race
2206 * If there is, we take a lock.
2209 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2210 bool *locked
, unsigned long *flags
)
2212 struct mem_cgroup
*memcg
;
2213 struct page_cgroup
*pc
;
2215 pc
= lookup_page_cgroup(page
);
2217 memcg
= pc
->mem_cgroup
;
2218 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2221 * If this memory cgroup is not under account moving, we don't
2222 * need to take move_lock_mem_cgroup(). Because we already hold
2223 * rcu_read_lock(), any calls to move_account will be delayed until
2224 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2226 if (!mem_cgroup_stolen(memcg
))
2229 move_lock_mem_cgroup(memcg
, flags
);
2230 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2231 move_unlock_mem_cgroup(memcg
, flags
);
2237 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2239 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2242 * It's guaranteed that pc->mem_cgroup never changes while
2243 * lock is held because a routine modifies pc->mem_cgroup
2244 * should take move_lock_mem_cgroup().
2246 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2249 void mem_cgroup_update_page_stat(struct page
*page
,
2250 enum mem_cgroup_page_stat_item idx
, int val
)
2252 struct mem_cgroup
*memcg
;
2253 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2254 unsigned long uninitialized_var(flags
);
2256 if (mem_cgroup_disabled())
2259 memcg
= pc
->mem_cgroup
;
2260 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2264 case MEMCG_NR_FILE_MAPPED
:
2265 idx
= MEM_CGROUP_STAT_FILE_MAPPED
;
2271 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2275 * size of first charge trial. "32" comes from vmscan.c's magic value.
2276 * TODO: maybe necessary to use big numbers in big irons.
2278 #define CHARGE_BATCH 32U
2279 struct memcg_stock_pcp
{
2280 struct mem_cgroup
*cached
; /* this never be root cgroup */
2281 unsigned int nr_pages
;
2282 struct work_struct work
;
2283 unsigned long flags
;
2284 #define FLUSHING_CACHED_CHARGE 0
2286 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2287 static DEFINE_MUTEX(percpu_charge_mutex
);
2290 * consume_stock: Try to consume stocked charge on this cpu.
2291 * @memcg: memcg to consume from.
2292 * @nr_pages: how many pages to charge.
2294 * The charges will only happen if @memcg matches the current cpu's memcg
2295 * stock, and at least @nr_pages are available in that stock. Failure to
2296 * service an allocation will refill the stock.
2298 * returns true if successful, false otherwise.
2300 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2302 struct memcg_stock_pcp
*stock
;
2305 if (nr_pages
> CHARGE_BATCH
)
2308 stock
= &get_cpu_var(memcg_stock
);
2309 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2310 stock
->nr_pages
-= nr_pages
;
2311 else /* need to call res_counter_charge */
2313 put_cpu_var(memcg_stock
);
2318 * Returns stocks cached in percpu to res_counter and reset cached information.
2320 static void drain_stock(struct memcg_stock_pcp
*stock
)
2322 struct mem_cgroup
*old
= stock
->cached
;
2324 if (stock
->nr_pages
) {
2325 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2327 res_counter_uncharge(&old
->res
, bytes
);
2328 if (do_swap_account
)
2329 res_counter_uncharge(&old
->memsw
, bytes
);
2330 stock
->nr_pages
= 0;
2332 stock
->cached
= NULL
;
2336 * This must be called under preempt disabled or must be called by
2337 * a thread which is pinned to local cpu.
2339 static void drain_local_stock(struct work_struct
*dummy
)
2341 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2343 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2346 static void __init
memcg_stock_init(void)
2350 for_each_possible_cpu(cpu
) {
2351 struct memcg_stock_pcp
*stock
=
2352 &per_cpu(memcg_stock
, cpu
);
2353 INIT_WORK(&stock
->work
, drain_local_stock
);
2358 * Cache charges(val) which is from res_counter, to local per_cpu area.
2359 * This will be consumed by consume_stock() function, later.
2361 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2363 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2365 if (stock
->cached
!= memcg
) { /* reset if necessary */
2367 stock
->cached
= memcg
;
2369 stock
->nr_pages
+= nr_pages
;
2370 put_cpu_var(memcg_stock
);
2374 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2375 * of the hierarchy under it. sync flag says whether we should block
2376 * until the work is done.
2378 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2382 /* Notify other cpus that system-wide "drain" is running */
2385 for_each_online_cpu(cpu
) {
2386 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2387 struct mem_cgroup
*memcg
;
2389 memcg
= stock
->cached
;
2390 if (!memcg
|| !stock
->nr_pages
)
2392 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2394 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2396 drain_local_stock(&stock
->work
);
2398 schedule_work_on(cpu
, &stock
->work
);
2406 for_each_online_cpu(cpu
) {
2407 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2408 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2409 flush_work(&stock
->work
);
2416 * Tries to drain stocked charges in other cpus. This function is asynchronous
2417 * and just put a work per cpu for draining localy on each cpu. Caller can
2418 * expects some charges will be back to res_counter later but cannot wait for
2421 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2424 * If someone calls draining, avoid adding more kworker runs.
2426 if (!mutex_trylock(&percpu_charge_mutex
))
2428 drain_all_stock(root_memcg
, false);
2429 mutex_unlock(&percpu_charge_mutex
);
2432 /* This is a synchronous drain interface. */
2433 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2435 /* called when force_empty is called */
2436 mutex_lock(&percpu_charge_mutex
);
2437 drain_all_stock(root_memcg
, true);
2438 mutex_unlock(&percpu_charge_mutex
);
2442 * This function drains percpu counter value from DEAD cpu and
2443 * move it to local cpu. Note that this function can be preempted.
2445 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2449 spin_lock(&memcg
->pcp_counter_lock
);
2450 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2451 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2453 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2454 memcg
->nocpu_base
.count
[i
] += x
;
2456 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2457 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2459 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2460 memcg
->nocpu_base
.events
[i
] += x
;
2462 spin_unlock(&memcg
->pcp_counter_lock
);
2465 static int __cpuinit
memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2466 unsigned long action
,
2469 int cpu
= (unsigned long)hcpu
;
2470 struct memcg_stock_pcp
*stock
;
2471 struct mem_cgroup
*iter
;
2473 if (action
== CPU_ONLINE
)
2476 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2479 for_each_mem_cgroup(iter
)
2480 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2482 stock
= &per_cpu(memcg_stock
, cpu
);
2488 /* See __mem_cgroup_try_charge() for details */
2490 CHARGE_OK
, /* success */
2491 CHARGE_RETRY
, /* need to retry but retry is not bad */
2492 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2493 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2494 CHARGE_OOM_DIE
, /* the current is killed because of OOM */
2497 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2498 unsigned int nr_pages
, unsigned int min_pages
,
2501 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2502 struct mem_cgroup
*mem_over_limit
;
2503 struct res_counter
*fail_res
;
2504 unsigned long flags
= 0;
2507 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2510 if (!do_swap_account
)
2512 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2516 res_counter_uncharge(&memcg
->res
, csize
);
2517 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2518 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2520 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2522 * Never reclaim on behalf of optional batching, retry with a
2523 * single page instead.
2525 if (nr_pages
> min_pages
)
2526 return CHARGE_RETRY
;
2528 if (!(gfp_mask
& __GFP_WAIT
))
2529 return CHARGE_WOULDBLOCK
;
2531 if (gfp_mask
& __GFP_NORETRY
)
2532 return CHARGE_NOMEM
;
2534 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2535 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2536 return CHARGE_RETRY
;
2538 * Even though the limit is exceeded at this point, reclaim
2539 * may have been able to free some pages. Retry the charge
2540 * before killing the task.
2542 * Only for regular pages, though: huge pages are rather
2543 * unlikely to succeed so close to the limit, and we fall back
2544 * to regular pages anyway in case of failure.
2546 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2547 return CHARGE_RETRY
;
2550 * At task move, charge accounts can be doubly counted. So, it's
2551 * better to wait until the end of task_move if something is going on.
2553 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2554 return CHARGE_RETRY
;
2556 /* If we don't need to call oom-killer at el, return immediately */
2558 return CHARGE_NOMEM
;
2560 if (!mem_cgroup_handle_oom(mem_over_limit
, gfp_mask
, get_order(csize
)))
2561 return CHARGE_OOM_DIE
;
2563 return CHARGE_RETRY
;
2567 * __mem_cgroup_try_charge() does
2568 * 1. detect memcg to be charged against from passed *mm and *ptr,
2569 * 2. update res_counter
2570 * 3. call memory reclaim if necessary.
2572 * In some special case, if the task is fatal, fatal_signal_pending() or
2573 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2574 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2575 * as possible without any hazards. 2: all pages should have a valid
2576 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2577 * pointer, that is treated as a charge to root_mem_cgroup.
2579 * So __mem_cgroup_try_charge() will return
2580 * 0 ... on success, filling *ptr with a valid memcg pointer.
2581 * -ENOMEM ... charge failure because of resource limits.
2582 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2584 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2585 * the oom-killer can be invoked.
2587 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2589 unsigned int nr_pages
,
2590 struct mem_cgroup
**ptr
,
2593 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2594 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2595 struct mem_cgroup
*memcg
= NULL
;
2599 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2600 * in system level. So, allow to go ahead dying process in addition to
2603 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2604 || fatal_signal_pending(current
)))
2608 * We always charge the cgroup the mm_struct belongs to.
2609 * The mm_struct's mem_cgroup changes on task migration if the
2610 * thread group leader migrates. It's possible that mm is not
2611 * set, if so charge the root memcg (happens for pagecache usage).
2614 *ptr
= root_mem_cgroup
;
2616 if (*ptr
) { /* css should be a valid one */
2618 if (mem_cgroup_is_root(memcg
))
2620 if (consume_stock(memcg
, nr_pages
))
2622 css_get(&memcg
->css
);
2624 struct task_struct
*p
;
2627 p
= rcu_dereference(mm
->owner
);
2629 * Because we don't have task_lock(), "p" can exit.
2630 * In that case, "memcg" can point to root or p can be NULL with
2631 * race with swapoff. Then, we have small risk of mis-accouning.
2632 * But such kind of mis-account by race always happens because
2633 * we don't have cgroup_mutex(). It's overkill and we allo that
2635 * (*) swapoff at el will charge against mm-struct not against
2636 * task-struct. So, mm->owner can be NULL.
2638 memcg
= mem_cgroup_from_task(p
);
2640 memcg
= root_mem_cgroup
;
2641 if (mem_cgroup_is_root(memcg
)) {
2645 if (consume_stock(memcg
, nr_pages
)) {
2647 * It seems dagerous to access memcg without css_get().
2648 * But considering how consume_stok works, it's not
2649 * necessary. If consume_stock success, some charges
2650 * from this memcg are cached on this cpu. So, we
2651 * don't need to call css_get()/css_tryget() before
2652 * calling consume_stock().
2657 /* after here, we may be blocked. we need to get refcnt */
2658 if (!css_tryget(&memcg
->css
)) {
2668 /* If killed, bypass charge */
2669 if (fatal_signal_pending(current
)) {
2670 css_put(&memcg
->css
);
2675 if (oom
&& !nr_oom_retries
) {
2677 nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2680 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
, nr_pages
,
2685 case CHARGE_RETRY
: /* not in OOM situation but retry */
2687 css_put(&memcg
->css
);
2690 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2691 css_put(&memcg
->css
);
2693 case CHARGE_NOMEM
: /* OOM routine works */
2695 css_put(&memcg
->css
);
2698 /* If oom, we never return -ENOMEM */
2701 case CHARGE_OOM_DIE
: /* Killed by OOM Killer */
2702 css_put(&memcg
->css
);
2705 } while (ret
!= CHARGE_OK
);
2707 if (batch
> nr_pages
)
2708 refill_stock(memcg
, batch
- nr_pages
);
2709 css_put(&memcg
->css
);
2717 *ptr
= root_mem_cgroup
;
2722 * Somemtimes we have to undo a charge we got by try_charge().
2723 * This function is for that and do uncharge, put css's refcnt.
2724 * gotten by try_charge().
2726 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2727 unsigned int nr_pages
)
2729 if (!mem_cgroup_is_root(memcg
)) {
2730 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2732 res_counter_uncharge(&memcg
->res
, bytes
);
2733 if (do_swap_account
)
2734 res_counter_uncharge(&memcg
->memsw
, bytes
);
2739 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2740 * This is useful when moving usage to parent cgroup.
2742 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2743 unsigned int nr_pages
)
2745 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2747 if (mem_cgroup_is_root(memcg
))
2750 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2751 if (do_swap_account
)
2752 res_counter_uncharge_until(&memcg
->memsw
,
2753 memcg
->memsw
.parent
, bytes
);
2757 * A helper function to get mem_cgroup from ID. must be called under
2758 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2759 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2760 * called against removed memcg.)
2762 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2764 struct cgroup_subsys_state
*css
;
2766 /* ID 0 is unused ID */
2769 css
= css_lookup(&mem_cgroup_subsys
, id
);
2772 return mem_cgroup_from_css(css
);
2775 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2777 struct mem_cgroup
*memcg
= NULL
;
2778 struct page_cgroup
*pc
;
2782 VM_BUG_ON(!PageLocked(page
));
2784 pc
= lookup_page_cgroup(page
);
2785 lock_page_cgroup(pc
);
2786 if (PageCgroupUsed(pc
)) {
2787 memcg
= pc
->mem_cgroup
;
2788 if (memcg
&& !css_tryget(&memcg
->css
))
2790 } else if (PageSwapCache(page
)) {
2791 ent
.val
= page_private(page
);
2792 id
= lookup_swap_cgroup_id(ent
);
2794 memcg
= mem_cgroup_lookup(id
);
2795 if (memcg
&& !css_tryget(&memcg
->css
))
2799 unlock_page_cgroup(pc
);
2803 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2805 unsigned int nr_pages
,
2806 enum charge_type ctype
,
2809 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2810 struct zone
*uninitialized_var(zone
);
2811 struct lruvec
*lruvec
;
2812 bool was_on_lru
= false;
2815 lock_page_cgroup(pc
);
2816 VM_BUG_ON(PageCgroupUsed(pc
));
2818 * we don't need page_cgroup_lock about tail pages, becase they are not
2819 * accessed by any other context at this point.
2823 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2824 * may already be on some other mem_cgroup's LRU. Take care of it.
2827 zone
= page_zone(page
);
2828 spin_lock_irq(&zone
->lru_lock
);
2829 if (PageLRU(page
)) {
2830 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2832 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2837 pc
->mem_cgroup
= memcg
;
2839 * We access a page_cgroup asynchronously without lock_page_cgroup().
2840 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2841 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2842 * before USED bit, we need memory barrier here.
2843 * See mem_cgroup_add_lru_list(), etc.
2846 SetPageCgroupUsed(pc
);
2850 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2851 VM_BUG_ON(PageLRU(page
));
2853 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2855 spin_unlock_irq(&zone
->lru_lock
);
2858 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2863 mem_cgroup_charge_statistics(memcg
, anon
, nr_pages
);
2864 unlock_page_cgroup(pc
);
2867 * "charge_statistics" updated event counter. Then, check it.
2868 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2869 * if they exceeds softlimit.
2871 memcg_check_events(memcg
, page
);
2874 static DEFINE_MUTEX(set_limit_mutex
);
2876 #ifdef CONFIG_MEMCG_KMEM
2877 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2879 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
2880 (memcg
->kmem_account_flags
& KMEM_ACCOUNTED_MASK
);
2884 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2885 * in the memcg_cache_params struct.
2887 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2889 struct kmem_cache
*cachep
;
2891 VM_BUG_ON(p
->is_root_cache
);
2892 cachep
= p
->root_cache
;
2893 return cachep
->memcg_params
->memcg_caches
[memcg_cache_id(p
->memcg
)];
2896 #ifdef CONFIG_SLABINFO
2897 static int mem_cgroup_slabinfo_read(struct cgroup
*cont
, struct cftype
*cft
,
2900 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
2901 struct memcg_cache_params
*params
;
2903 if (!memcg_can_account_kmem(memcg
))
2906 print_slabinfo_header(m
);
2908 mutex_lock(&memcg
->slab_caches_mutex
);
2909 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
2910 cache_show(memcg_params_to_cache(params
), m
);
2911 mutex_unlock(&memcg
->slab_caches_mutex
);
2917 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
2919 struct res_counter
*fail_res
;
2920 struct mem_cgroup
*_memcg
;
2924 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
2929 * Conditions under which we can wait for the oom_killer. Those are
2930 * the same conditions tested by the core page allocator
2932 may_oom
= (gfp
& __GFP_FS
) && !(gfp
& __GFP_NORETRY
);
2935 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
2938 if (ret
== -EINTR
) {
2940 * __mem_cgroup_try_charge() chosed to bypass to root due to
2941 * OOM kill or fatal signal. Since our only options are to
2942 * either fail the allocation or charge it to this cgroup, do
2943 * it as a temporary condition. But we can't fail. From a
2944 * kmem/slab perspective, the cache has already been selected,
2945 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2948 * This condition will only trigger if the task entered
2949 * memcg_charge_kmem in a sane state, but was OOM-killed during
2950 * __mem_cgroup_try_charge() above. Tasks that were already
2951 * dying when the allocation triggers should have been already
2952 * directed to the root cgroup in memcontrol.h
2954 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
2955 if (do_swap_account
)
2956 res_counter_charge_nofail(&memcg
->memsw
, size
,
2960 res_counter_uncharge(&memcg
->kmem
, size
);
2965 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
2967 res_counter_uncharge(&memcg
->res
, size
);
2968 if (do_swap_account
)
2969 res_counter_uncharge(&memcg
->memsw
, size
);
2972 if (res_counter_uncharge(&memcg
->kmem
, size
))
2975 if (memcg_kmem_test_and_clear_dead(memcg
))
2976 mem_cgroup_put(memcg
);
2979 void memcg_cache_list_add(struct mem_cgroup
*memcg
, struct kmem_cache
*cachep
)
2984 mutex_lock(&memcg
->slab_caches_mutex
);
2985 list_add(&cachep
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
2986 mutex_unlock(&memcg
->slab_caches_mutex
);
2990 * helper for acessing a memcg's index. It will be used as an index in the
2991 * child cache array in kmem_cache, and also to derive its name. This function
2992 * will return -1 when this is not a kmem-limited memcg.
2994 int memcg_cache_id(struct mem_cgroup
*memcg
)
2996 return memcg
? memcg
->kmemcg_id
: -1;
3000 * This ends up being protected by the set_limit mutex, during normal
3001 * operation, because that is its main call site.
3003 * But when we create a new cache, we can call this as well if its parent
3004 * is kmem-limited. That will have to hold set_limit_mutex as well.
3006 int memcg_update_cache_sizes(struct mem_cgroup
*memcg
)
3010 num
= ida_simple_get(&kmem_limited_groups
,
3011 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
3015 * After this point, kmem_accounted (that we test atomically in
3016 * the beginning of this conditional), is no longer 0. This
3017 * guarantees only one process will set the following boolean
3018 * to true. We don't need test_and_set because we're protected
3019 * by the set_limit_mutex anyway.
3021 memcg_kmem_set_activated(memcg
);
3023 ret
= memcg_update_all_caches(num
+1);
3025 ida_simple_remove(&kmem_limited_groups
, num
);
3026 memcg_kmem_clear_activated(memcg
);
3030 memcg
->kmemcg_id
= num
;
3031 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
3032 mutex_init(&memcg
->slab_caches_mutex
);
3036 static size_t memcg_caches_array_size(int num_groups
)
3039 if (num_groups
<= 0)
3042 size
= 2 * num_groups
;
3043 if (size
< MEMCG_CACHES_MIN_SIZE
)
3044 size
= MEMCG_CACHES_MIN_SIZE
;
3045 else if (size
> MEMCG_CACHES_MAX_SIZE
)
3046 size
= MEMCG_CACHES_MAX_SIZE
;
3052 * We should update the current array size iff all caches updates succeed. This
3053 * can only be done from the slab side. The slab mutex needs to be held when
3056 void memcg_update_array_size(int num
)
3058 if (num
> memcg_limited_groups_array_size
)
3059 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3062 static void kmem_cache_destroy_work_func(struct work_struct
*w
);
3064 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3066 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3068 VM_BUG_ON(s
->memcg_params
&& !s
->memcg_params
->is_root_cache
);
3070 if (num_groups
> memcg_limited_groups_array_size
) {
3072 ssize_t size
= memcg_caches_array_size(num_groups
);
3074 size
*= sizeof(void *);
3075 size
+= sizeof(struct memcg_cache_params
);
3077 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3078 if (!s
->memcg_params
) {
3079 s
->memcg_params
= cur_params
;
3083 INIT_WORK(&s
->memcg_params
->destroy
,
3084 kmem_cache_destroy_work_func
);
3085 s
->memcg_params
->is_root_cache
= true;
3088 * There is the chance it will be bigger than
3089 * memcg_limited_groups_array_size, if we failed an allocation
3090 * in a cache, in which case all caches updated before it, will
3091 * have a bigger array.
3093 * But if that is the case, the data after
3094 * memcg_limited_groups_array_size is certainly unused
3096 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3097 if (!cur_params
->memcg_caches
[i
])
3099 s
->memcg_params
->memcg_caches
[i
] =
3100 cur_params
->memcg_caches
[i
];
3104 * Ideally, we would wait until all caches succeed, and only
3105 * then free the old one. But this is not worth the extra
3106 * pointer per-cache we'd have to have for this.
3108 * It is not a big deal if some caches are left with a size
3109 * bigger than the others. And all updates will reset this
3117 int memcg_register_cache(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3118 struct kmem_cache
*root_cache
)
3120 size_t size
= sizeof(struct memcg_cache_params
);
3122 if (!memcg_kmem_enabled())
3126 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3128 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3129 if (!s
->memcg_params
)
3132 INIT_WORK(&s
->memcg_params
->destroy
,
3133 kmem_cache_destroy_work_func
);
3135 s
->memcg_params
->memcg
= memcg
;
3136 s
->memcg_params
->root_cache
= root_cache
;
3138 s
->memcg_params
->is_root_cache
= true;
3143 void memcg_release_cache(struct kmem_cache
*s
)
3145 struct kmem_cache
*root
;
3146 struct mem_cgroup
*memcg
;
3150 * This happens, for instance, when a root cache goes away before we
3153 if (!s
->memcg_params
)
3156 if (s
->memcg_params
->is_root_cache
)
3159 memcg
= s
->memcg_params
->memcg
;
3160 id
= memcg_cache_id(memcg
);
3162 root
= s
->memcg_params
->root_cache
;
3163 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3164 mem_cgroup_put(memcg
);
3166 mutex_lock(&memcg
->slab_caches_mutex
);
3167 list_del(&s
->memcg_params
->list
);
3168 mutex_unlock(&memcg
->slab_caches_mutex
);
3171 kfree(s
->memcg_params
);
3175 * During the creation a new cache, we need to disable our accounting mechanism
3176 * altogether. This is true even if we are not creating, but rather just
3177 * enqueing new caches to be created.
3179 * This is because that process will trigger allocations; some visible, like
3180 * explicit kmallocs to auxiliary data structures, name strings and internal
3181 * cache structures; some well concealed, like INIT_WORK() that can allocate
3182 * objects during debug.
3184 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3185 * to it. This may not be a bounded recursion: since the first cache creation
3186 * failed to complete (waiting on the allocation), we'll just try to create the
3187 * cache again, failing at the same point.
3189 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3190 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3191 * inside the following two functions.
3193 static inline void memcg_stop_kmem_account(void)
3195 VM_BUG_ON(!current
->mm
);
3196 current
->memcg_kmem_skip_account
++;
3199 static inline void memcg_resume_kmem_account(void)
3201 VM_BUG_ON(!current
->mm
);
3202 current
->memcg_kmem_skip_account
--;
3205 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3207 struct kmem_cache
*cachep
;
3208 struct memcg_cache_params
*p
;
3210 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3212 cachep
= memcg_params_to_cache(p
);
3215 * If we get down to 0 after shrink, we could delete right away.
3216 * However, memcg_release_pages() already puts us back in the workqueue
3217 * in that case. If we proceed deleting, we'll get a dangling
3218 * reference, and removing the object from the workqueue in that case
3219 * is unnecessary complication. We are not a fast path.
3221 * Note that this case is fundamentally different from racing with
3222 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3223 * kmem_cache_shrink, not only we would be reinserting a dead cache
3224 * into the queue, but doing so from inside the worker racing to
3227 * So if we aren't down to zero, we'll just schedule a worker and try
3230 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0) {
3231 kmem_cache_shrink(cachep
);
3232 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
3235 kmem_cache_destroy(cachep
);
3238 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3240 if (!cachep
->memcg_params
->dead
)
3244 * There are many ways in which we can get here.
3246 * We can get to a memory-pressure situation while the delayed work is
3247 * still pending to run. The vmscan shrinkers can then release all
3248 * cache memory and get us to destruction. If this is the case, we'll
3249 * be executed twice, which is a bug (the second time will execute over
3250 * bogus data). In this case, cancelling the work should be fine.
3252 * But we can also get here from the worker itself, if
3253 * kmem_cache_shrink is enough to shake all the remaining objects and
3254 * get the page count to 0. In this case, we'll deadlock if we try to
3255 * cancel the work (the worker runs with an internal lock held, which
3256 * is the same lock we would hold for cancel_work_sync().)
3258 * Since we can't possibly know who got us here, just refrain from
3259 * running if there is already work pending
3261 if (work_pending(&cachep
->memcg_params
->destroy
))
3264 * We have to defer the actual destroying to a workqueue, because
3265 * we might currently be in a context that cannot sleep.
3267 schedule_work(&cachep
->memcg_params
->destroy
);
3270 static char *memcg_cache_name(struct mem_cgroup
*memcg
, struct kmem_cache
*s
)
3273 struct dentry
*dentry
;
3276 dentry
= rcu_dereference(memcg
->css
.cgroup
->dentry
);
3279 BUG_ON(dentry
== NULL
);
3281 name
= kasprintf(GFP_KERNEL
, "%s(%d:%s)", s
->name
,
3282 memcg_cache_id(memcg
), dentry
->d_name
.name
);
3287 static struct kmem_cache
*kmem_cache_dup(struct mem_cgroup
*memcg
,
3288 struct kmem_cache
*s
)
3291 struct kmem_cache
*new;
3293 name
= memcg_cache_name(memcg
, s
);
3297 new = kmem_cache_create_memcg(memcg
, name
, s
->object_size
, s
->align
,
3298 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3301 new->allocflags
|= __GFP_KMEMCG
;
3308 * This lock protects updaters, not readers. We want readers to be as fast as
3309 * they can, and they will either see NULL or a valid cache value. Our model
3310 * allow them to see NULL, in which case the root memcg will be selected.
3312 * We need this lock because multiple allocations to the same cache from a non
3313 * will span more than one worker. Only one of them can create the cache.
3315 static DEFINE_MUTEX(memcg_cache_mutex
);
3316 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3317 struct kmem_cache
*cachep
)
3319 struct kmem_cache
*new_cachep
;
3322 BUG_ON(!memcg_can_account_kmem(memcg
));
3324 idx
= memcg_cache_id(memcg
);
3326 mutex_lock(&memcg_cache_mutex
);
3327 new_cachep
= cachep
->memcg_params
->memcg_caches
[idx
];
3331 new_cachep
= kmem_cache_dup(memcg
, cachep
);
3332 if (new_cachep
== NULL
) {
3333 new_cachep
= cachep
;
3337 mem_cgroup_get(memcg
);
3338 atomic_set(&new_cachep
->memcg_params
->nr_pages
, 0);
3340 cachep
->memcg_params
->memcg_caches
[idx
] = new_cachep
;
3342 * the readers won't lock, make sure everybody sees the updated value,
3343 * so they won't put stuff in the queue again for no reason
3347 mutex_unlock(&memcg_cache_mutex
);
3351 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3353 struct kmem_cache
*c
;
3356 if (!s
->memcg_params
)
3358 if (!s
->memcg_params
->is_root_cache
)
3362 * If the cache is being destroyed, we trust that there is no one else
3363 * requesting objects from it. Even if there are, the sanity checks in
3364 * kmem_cache_destroy should caught this ill-case.
3366 * Still, we don't want anyone else freeing memcg_caches under our
3367 * noses, which can happen if a new memcg comes to life. As usual,
3368 * we'll take the set_limit_mutex to protect ourselves against this.
3370 mutex_lock(&set_limit_mutex
);
3371 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3372 c
= s
->memcg_params
->memcg_caches
[i
];
3377 * We will now manually delete the caches, so to avoid races
3378 * we need to cancel all pending destruction workers and
3379 * proceed with destruction ourselves.
3381 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3382 * and that could spawn the workers again: it is likely that
3383 * the cache still have active pages until this very moment.
3384 * This would lead us back to mem_cgroup_destroy_cache.
3386 * But that will not execute at all if the "dead" flag is not
3387 * set, so flip it down to guarantee we are in control.
3389 c
->memcg_params
->dead
= false;
3390 cancel_work_sync(&c
->memcg_params
->destroy
);
3391 kmem_cache_destroy(c
);
3393 mutex_unlock(&set_limit_mutex
);
3396 struct create_work
{
3397 struct mem_cgroup
*memcg
;
3398 struct kmem_cache
*cachep
;
3399 struct work_struct work
;
3402 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3404 struct kmem_cache
*cachep
;
3405 struct memcg_cache_params
*params
;
3407 if (!memcg_kmem_is_active(memcg
))
3410 mutex_lock(&memcg
->slab_caches_mutex
);
3411 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3412 cachep
= memcg_params_to_cache(params
);
3413 cachep
->memcg_params
->dead
= true;
3414 schedule_work(&cachep
->memcg_params
->destroy
);
3416 mutex_unlock(&memcg
->slab_caches_mutex
);
3419 static void memcg_create_cache_work_func(struct work_struct
*w
)
3421 struct create_work
*cw
;
3423 cw
= container_of(w
, struct create_work
, work
);
3424 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3425 /* Drop the reference gotten when we enqueued. */
3426 css_put(&cw
->memcg
->css
);
3431 * Enqueue the creation of a per-memcg kmem_cache.
3432 * Called with rcu_read_lock.
3434 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3435 struct kmem_cache
*cachep
)
3437 struct create_work
*cw
;
3439 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3443 /* The corresponding put will be done in the workqueue. */
3444 if (!css_tryget(&memcg
->css
)) {
3450 cw
->cachep
= cachep
;
3452 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3453 schedule_work(&cw
->work
);
3456 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3457 struct kmem_cache
*cachep
)
3460 * We need to stop accounting when we kmalloc, because if the
3461 * corresponding kmalloc cache is not yet created, the first allocation
3462 * in __memcg_create_cache_enqueue will recurse.
3464 * However, it is better to enclose the whole function. Depending on
3465 * the debugging options enabled, INIT_WORK(), for instance, can
3466 * trigger an allocation. This too, will make us recurse. Because at
3467 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3468 * the safest choice is to do it like this, wrapping the whole function.
3470 memcg_stop_kmem_account();
3471 __memcg_create_cache_enqueue(memcg
, cachep
);
3472 memcg_resume_kmem_account();
3475 * Return the kmem_cache we're supposed to use for a slab allocation.
3476 * We try to use the current memcg's version of the cache.
3478 * If the cache does not exist yet, if we are the first user of it,
3479 * we either create it immediately, if possible, or create it asynchronously
3481 * In the latter case, we will let the current allocation go through with
3482 * the original cache.
3484 * Can't be called in interrupt context or from kernel threads.
3485 * This function needs to be called with rcu_read_lock() held.
3487 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3490 struct mem_cgroup
*memcg
;
3493 VM_BUG_ON(!cachep
->memcg_params
);
3494 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3496 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3500 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3503 if (!memcg_can_account_kmem(memcg
))
3506 idx
= memcg_cache_id(memcg
);
3509 * barrier to mare sure we're always seeing the up to date value. The
3510 * code updating memcg_caches will issue a write barrier to match this.
3512 read_barrier_depends();
3513 if (unlikely(cachep
->memcg_params
->memcg_caches
[idx
] == NULL
)) {
3515 * If we are in a safe context (can wait, and not in interrupt
3516 * context), we could be be predictable and return right away.
3517 * This would guarantee that the allocation being performed
3518 * already belongs in the new cache.
3520 * However, there are some clashes that can arrive from locking.
3521 * For instance, because we acquire the slab_mutex while doing
3522 * kmem_cache_dup, this means no further allocation could happen
3523 * with the slab_mutex held.
3525 * Also, because cache creation issue get_online_cpus(), this
3526 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3527 * that ends up reversed during cpu hotplug. (cpuset allocates
3528 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3529 * better to defer everything.
3531 memcg_create_cache_enqueue(memcg
, cachep
);
3535 return cachep
->memcg_params
->memcg_caches
[idx
];
3537 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3540 * We need to verify if the allocation against current->mm->owner's memcg is
3541 * possible for the given order. But the page is not allocated yet, so we'll
3542 * need a further commit step to do the final arrangements.
3544 * It is possible for the task to switch cgroups in this mean time, so at
3545 * commit time, we can't rely on task conversion any longer. We'll then use
3546 * the handle argument to return to the caller which cgroup we should commit
3547 * against. We could also return the memcg directly and avoid the pointer
3548 * passing, but a boolean return value gives better semantics considering
3549 * the compiled-out case as well.
3551 * Returning true means the allocation is possible.
3554 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3556 struct mem_cgroup
*memcg
;
3560 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3563 * very rare case described in mem_cgroup_from_task. Unfortunately there
3564 * isn't much we can do without complicating this too much, and it would
3565 * be gfp-dependent anyway. Just let it go
3567 if (unlikely(!memcg
))
3570 if (!memcg_can_account_kmem(memcg
)) {
3571 css_put(&memcg
->css
);
3575 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3579 css_put(&memcg
->css
);
3583 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3586 struct page_cgroup
*pc
;
3588 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3590 /* The page allocation failed. Revert */
3592 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3596 pc
= lookup_page_cgroup(page
);
3597 lock_page_cgroup(pc
);
3598 pc
->mem_cgroup
= memcg
;
3599 SetPageCgroupUsed(pc
);
3600 unlock_page_cgroup(pc
);
3603 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3605 struct mem_cgroup
*memcg
= NULL
;
3606 struct page_cgroup
*pc
;
3609 pc
= lookup_page_cgroup(page
);
3611 * Fast unlocked return. Theoretically might have changed, have to
3612 * check again after locking.
3614 if (!PageCgroupUsed(pc
))
3617 lock_page_cgroup(pc
);
3618 if (PageCgroupUsed(pc
)) {
3619 memcg
= pc
->mem_cgroup
;
3620 ClearPageCgroupUsed(pc
);
3622 unlock_page_cgroup(pc
);
3625 * We trust that only if there is a memcg associated with the page, it
3626 * is a valid allocation
3631 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3632 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3635 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3638 #endif /* CONFIG_MEMCG_KMEM */
3640 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3642 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3644 * Because tail pages are not marked as "used", set it. We're under
3645 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3646 * charge/uncharge will be never happen and move_account() is done under
3647 * compound_lock(), so we don't have to take care of races.
3649 void mem_cgroup_split_huge_fixup(struct page
*head
)
3651 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3652 struct page_cgroup
*pc
;
3655 if (mem_cgroup_disabled())
3657 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3659 pc
->mem_cgroup
= head_pc
->mem_cgroup
;
3660 smp_wmb();/* see __commit_charge() */
3661 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3664 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3667 * mem_cgroup_move_account - move account of the page
3669 * @nr_pages: number of regular pages (>1 for huge pages)
3670 * @pc: page_cgroup of the page.
3671 * @from: mem_cgroup which the page is moved from.
3672 * @to: mem_cgroup which the page is moved to. @from != @to.
3674 * The caller must confirm following.
3675 * - page is not on LRU (isolate_page() is useful.)
3676 * - compound_lock is held when nr_pages > 1
3678 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3681 static int mem_cgroup_move_account(struct page
*page
,
3682 unsigned int nr_pages
,
3683 struct page_cgroup
*pc
,
3684 struct mem_cgroup
*from
,
3685 struct mem_cgroup
*to
)
3687 unsigned long flags
;
3689 bool anon
= PageAnon(page
);
3691 VM_BUG_ON(from
== to
);
3692 VM_BUG_ON(PageLRU(page
));
3694 * The page is isolated from LRU. So, collapse function
3695 * will not handle this page. But page splitting can happen.
3696 * Do this check under compound_page_lock(). The caller should
3700 if (nr_pages
> 1 && !PageTransHuge(page
))
3703 lock_page_cgroup(pc
);
3706 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3709 move_lock_mem_cgroup(from
, &flags
);
3711 if (!anon
&& page_mapped(page
)) {
3712 /* Update mapped_file data for mem_cgroup */
3714 __this_cpu_dec(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3715 __this_cpu_inc(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3718 mem_cgroup_charge_statistics(from
, anon
, -nr_pages
);
3720 /* caller should have done css_get */
3721 pc
->mem_cgroup
= to
;
3722 mem_cgroup_charge_statistics(to
, anon
, nr_pages
);
3723 move_unlock_mem_cgroup(from
, &flags
);
3726 unlock_page_cgroup(pc
);
3730 memcg_check_events(to
, page
);
3731 memcg_check_events(from
, page
);
3737 * mem_cgroup_move_parent - moves page to the parent group
3738 * @page: the page to move
3739 * @pc: page_cgroup of the page
3740 * @child: page's cgroup
3742 * move charges to its parent or the root cgroup if the group has no
3743 * parent (aka use_hierarchy==0).
3744 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3745 * mem_cgroup_move_account fails) the failure is always temporary and
3746 * it signals a race with a page removal/uncharge or migration. In the
3747 * first case the page is on the way out and it will vanish from the LRU
3748 * on the next attempt and the call should be retried later.
3749 * Isolation from the LRU fails only if page has been isolated from
3750 * the LRU since we looked at it and that usually means either global
3751 * reclaim or migration going on. The page will either get back to the
3753 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3754 * (!PageCgroupUsed) or moved to a different group. The page will
3755 * disappear in the next attempt.
3757 static int mem_cgroup_move_parent(struct page
*page
,
3758 struct page_cgroup
*pc
,
3759 struct mem_cgroup
*child
)
3761 struct mem_cgroup
*parent
;
3762 unsigned int nr_pages
;
3763 unsigned long uninitialized_var(flags
);
3766 VM_BUG_ON(mem_cgroup_is_root(child
));
3769 if (!get_page_unless_zero(page
))
3771 if (isolate_lru_page(page
))
3774 nr_pages
= hpage_nr_pages(page
);
3776 parent
= parent_mem_cgroup(child
);
3778 * If no parent, move charges to root cgroup.
3781 parent
= root_mem_cgroup
;
3784 VM_BUG_ON(!PageTransHuge(page
));
3785 flags
= compound_lock_irqsave(page
);
3788 ret
= mem_cgroup_move_account(page
, nr_pages
,
3791 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3794 compound_unlock_irqrestore(page
, flags
);
3795 putback_lru_page(page
);
3803 * Charge the memory controller for page usage.
3805 * 0 if the charge was successful
3806 * < 0 if the cgroup is over its limit
3808 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
3809 gfp_t gfp_mask
, enum charge_type ctype
)
3811 struct mem_cgroup
*memcg
= NULL
;
3812 unsigned int nr_pages
= 1;
3816 if (PageTransHuge(page
)) {
3817 nr_pages
<<= compound_order(page
);
3818 VM_BUG_ON(!PageTransHuge(page
));
3820 * Never OOM-kill a process for a huge page. The
3821 * fault handler will fall back to regular pages.
3826 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
3829 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
3833 int mem_cgroup_newpage_charge(struct page
*page
,
3834 struct mm_struct
*mm
, gfp_t gfp_mask
)
3836 if (mem_cgroup_disabled())
3838 VM_BUG_ON(page_mapped(page
));
3839 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
3841 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
3842 MEM_CGROUP_CHARGE_TYPE_ANON
);
3846 * While swap-in, try_charge -> commit or cancel, the page is locked.
3847 * And when try_charge() successfully returns, one refcnt to memcg without
3848 * struct page_cgroup is acquired. This refcnt will be consumed by
3849 * "commit()" or removed by "cancel()"
3851 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
3854 struct mem_cgroup
**memcgp
)
3856 struct mem_cgroup
*memcg
;
3857 struct page_cgroup
*pc
;
3860 pc
= lookup_page_cgroup(page
);
3862 * Every swap fault against a single page tries to charge the
3863 * page, bail as early as possible. shmem_unuse() encounters
3864 * already charged pages, too. The USED bit is protected by
3865 * the page lock, which serializes swap cache removal, which
3866 * in turn serializes uncharging.
3868 if (PageCgroupUsed(pc
))
3870 if (!do_swap_account
)
3872 memcg
= try_get_mem_cgroup_from_page(page
);
3876 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
3877 css_put(&memcg
->css
);
3882 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
3888 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
3889 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
3892 if (mem_cgroup_disabled())
3895 * A racing thread's fault, or swapoff, may have already
3896 * updated the pte, and even removed page from swap cache: in
3897 * those cases unuse_pte()'s pte_same() test will fail; but
3898 * there's also a KSM case which does need to charge the page.
3900 if (!PageSwapCache(page
)) {
3903 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
3908 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
3911 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
3913 if (mem_cgroup_disabled())
3917 __mem_cgroup_cancel_charge(memcg
, 1);
3921 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
3922 enum charge_type ctype
)
3924 if (mem_cgroup_disabled())
3929 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
3931 * Now swap is on-memory. This means this page may be
3932 * counted both as mem and swap....double count.
3933 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3934 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3935 * may call delete_from_swap_cache() before reach here.
3937 if (do_swap_account
&& PageSwapCache(page
)) {
3938 swp_entry_t ent
= {.val
= page_private(page
)};
3939 mem_cgroup_uncharge_swap(ent
);
3943 void mem_cgroup_commit_charge_swapin(struct page
*page
,
3944 struct mem_cgroup
*memcg
)
3946 __mem_cgroup_commit_charge_swapin(page
, memcg
,
3947 MEM_CGROUP_CHARGE_TYPE_ANON
);
3950 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
3953 struct mem_cgroup
*memcg
= NULL
;
3954 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
3957 if (mem_cgroup_disabled())
3959 if (PageCompound(page
))
3962 if (!PageSwapCache(page
))
3963 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
3964 else { /* page is swapcache/shmem */
3965 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
3968 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
3973 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
3974 unsigned int nr_pages
,
3975 const enum charge_type ctype
)
3977 struct memcg_batch_info
*batch
= NULL
;
3978 bool uncharge_memsw
= true;
3980 /* If swapout, usage of swap doesn't decrease */
3981 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
3982 uncharge_memsw
= false;
3984 batch
= ¤t
->memcg_batch
;
3986 * In usual, we do css_get() when we remember memcg pointer.
3987 * But in this case, we keep res->usage until end of a series of
3988 * uncharges. Then, it's ok to ignore memcg's refcnt.
3991 batch
->memcg
= memcg
;
3993 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3994 * In those cases, all pages freed continuously can be expected to be in
3995 * the same cgroup and we have chance to coalesce uncharges.
3996 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3997 * because we want to do uncharge as soon as possible.
4000 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
4001 goto direct_uncharge
;
4004 goto direct_uncharge
;
4007 * In typical case, batch->memcg == mem. This means we can
4008 * merge a series of uncharges to an uncharge of res_counter.
4009 * If not, we uncharge res_counter ony by one.
4011 if (batch
->memcg
!= memcg
)
4012 goto direct_uncharge
;
4013 /* remember freed charge and uncharge it later */
4016 batch
->memsw_nr_pages
++;
4019 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
4021 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
4022 if (unlikely(batch
->memcg
!= memcg
))
4023 memcg_oom_recover(memcg
);
4027 * uncharge if !page_mapped(page)
4029 static struct mem_cgroup
*
4030 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
4033 struct mem_cgroup
*memcg
= NULL
;
4034 unsigned int nr_pages
= 1;
4035 struct page_cgroup
*pc
;
4038 if (mem_cgroup_disabled())
4041 VM_BUG_ON(PageSwapCache(page
));
4043 if (PageTransHuge(page
)) {
4044 nr_pages
<<= compound_order(page
);
4045 VM_BUG_ON(!PageTransHuge(page
));
4048 * Check if our page_cgroup is valid
4050 pc
= lookup_page_cgroup(page
);
4051 if (unlikely(!PageCgroupUsed(pc
)))
4054 lock_page_cgroup(pc
);
4056 memcg
= pc
->mem_cgroup
;
4058 if (!PageCgroupUsed(pc
))
4061 anon
= PageAnon(page
);
4064 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4066 * Generally PageAnon tells if it's the anon statistics to be
4067 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4068 * used before page reached the stage of being marked PageAnon.
4072 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4073 /* See mem_cgroup_prepare_migration() */
4074 if (page_mapped(page
))
4077 * Pages under migration may not be uncharged. But
4078 * end_migration() /must/ be the one uncharging the
4079 * unused post-migration page and so it has to call
4080 * here with the migration bit still set. See the
4081 * res_counter handling below.
4083 if (!end_migration
&& PageCgroupMigration(pc
))
4086 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4087 if (!PageAnon(page
)) { /* Shared memory */
4088 if (page
->mapping
&& !page_is_file_cache(page
))
4090 } else if (page_mapped(page
)) /* Anon */
4097 mem_cgroup_charge_statistics(memcg
, anon
, -nr_pages
);
4099 ClearPageCgroupUsed(pc
);
4101 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4102 * freed from LRU. This is safe because uncharged page is expected not
4103 * to be reused (freed soon). Exception is SwapCache, it's handled by
4104 * special functions.
4107 unlock_page_cgroup(pc
);
4109 * even after unlock, we have memcg->res.usage here and this memcg
4110 * will never be freed.
4112 memcg_check_events(memcg
, page
);
4113 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4114 mem_cgroup_swap_statistics(memcg
, true);
4115 mem_cgroup_get(memcg
);
4118 * Migration does not charge the res_counter for the
4119 * replacement page, so leave it alone when phasing out the
4120 * page that is unused after the migration.
4122 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4123 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4128 unlock_page_cgroup(pc
);
4132 void mem_cgroup_uncharge_page(struct page
*page
)
4135 if (page_mapped(page
))
4137 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
4138 if (PageSwapCache(page
))
4140 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4143 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4145 VM_BUG_ON(page_mapped(page
));
4146 VM_BUG_ON(page
->mapping
);
4147 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4151 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4152 * In that cases, pages are freed continuously and we can expect pages
4153 * are in the same memcg. All these calls itself limits the number of
4154 * pages freed at once, then uncharge_start/end() is called properly.
4155 * This may be called prural(2) times in a context,
4158 void mem_cgroup_uncharge_start(void)
4160 current
->memcg_batch
.do_batch
++;
4161 /* We can do nest. */
4162 if (current
->memcg_batch
.do_batch
== 1) {
4163 current
->memcg_batch
.memcg
= NULL
;
4164 current
->memcg_batch
.nr_pages
= 0;
4165 current
->memcg_batch
.memsw_nr_pages
= 0;
4169 void mem_cgroup_uncharge_end(void)
4171 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4173 if (!batch
->do_batch
)
4177 if (batch
->do_batch
) /* If stacked, do nothing. */
4183 * This "batch->memcg" is valid without any css_get/put etc...
4184 * bacause we hide charges behind us.
4186 if (batch
->nr_pages
)
4187 res_counter_uncharge(&batch
->memcg
->res
,
4188 batch
->nr_pages
* PAGE_SIZE
);
4189 if (batch
->memsw_nr_pages
)
4190 res_counter_uncharge(&batch
->memcg
->memsw
,
4191 batch
->memsw_nr_pages
* PAGE_SIZE
);
4192 memcg_oom_recover(batch
->memcg
);
4193 /* forget this pointer (for sanity check) */
4194 batch
->memcg
= NULL
;
4199 * called after __delete_from_swap_cache() and drop "page" account.
4200 * memcg information is recorded to swap_cgroup of "ent"
4203 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4205 struct mem_cgroup
*memcg
;
4206 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4208 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4209 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4211 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4214 * record memcg information, if swapout && memcg != NULL,
4215 * mem_cgroup_get() was called in uncharge().
4217 if (do_swap_account
&& swapout
&& memcg
)
4218 swap_cgroup_record(ent
, css_id(&memcg
->css
));
4222 #ifdef CONFIG_MEMCG_SWAP
4224 * called from swap_entry_free(). remove record in swap_cgroup and
4225 * uncharge "memsw" account.
4227 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4229 struct mem_cgroup
*memcg
;
4232 if (!do_swap_account
)
4235 id
= swap_cgroup_record(ent
, 0);
4237 memcg
= mem_cgroup_lookup(id
);
4240 * We uncharge this because swap is freed.
4241 * This memcg can be obsolete one. We avoid calling css_tryget
4243 if (!mem_cgroup_is_root(memcg
))
4244 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4245 mem_cgroup_swap_statistics(memcg
, false);
4246 mem_cgroup_put(memcg
);
4252 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4253 * @entry: swap entry to be moved
4254 * @from: mem_cgroup which the entry is moved from
4255 * @to: mem_cgroup which the entry is moved to
4257 * It succeeds only when the swap_cgroup's record for this entry is the same
4258 * as the mem_cgroup's id of @from.
4260 * Returns 0 on success, -EINVAL on failure.
4262 * The caller must have charged to @to, IOW, called res_counter_charge() about
4263 * both res and memsw, and called css_get().
4265 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4266 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4268 unsigned short old_id
, new_id
;
4270 old_id
= css_id(&from
->css
);
4271 new_id
= css_id(&to
->css
);
4273 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4274 mem_cgroup_swap_statistics(from
, false);
4275 mem_cgroup_swap_statistics(to
, true);
4277 * This function is only called from task migration context now.
4278 * It postpones res_counter and refcount handling till the end
4279 * of task migration(mem_cgroup_clear_mc()) for performance
4280 * improvement. But we cannot postpone mem_cgroup_get(to)
4281 * because if the process that has been moved to @to does
4282 * swap-in, the refcount of @to might be decreased to 0.
4290 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4291 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4298 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4301 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4302 struct mem_cgroup
**memcgp
)
4304 struct mem_cgroup
*memcg
= NULL
;
4305 unsigned int nr_pages
= 1;
4306 struct page_cgroup
*pc
;
4307 enum charge_type ctype
;
4311 if (mem_cgroup_disabled())
4314 if (PageTransHuge(page
))
4315 nr_pages
<<= compound_order(page
);
4317 pc
= lookup_page_cgroup(page
);
4318 lock_page_cgroup(pc
);
4319 if (PageCgroupUsed(pc
)) {
4320 memcg
= pc
->mem_cgroup
;
4321 css_get(&memcg
->css
);
4323 * At migrating an anonymous page, its mapcount goes down
4324 * to 0 and uncharge() will be called. But, even if it's fully
4325 * unmapped, migration may fail and this page has to be
4326 * charged again. We set MIGRATION flag here and delay uncharge
4327 * until end_migration() is called
4329 * Corner Case Thinking
4331 * When the old page was mapped as Anon and it's unmap-and-freed
4332 * while migration was ongoing.
4333 * If unmap finds the old page, uncharge() of it will be delayed
4334 * until end_migration(). If unmap finds a new page, it's
4335 * uncharged when it make mapcount to be 1->0. If unmap code
4336 * finds swap_migration_entry, the new page will not be mapped
4337 * and end_migration() will find it(mapcount==0).
4340 * When the old page was mapped but migraion fails, the kernel
4341 * remaps it. A charge for it is kept by MIGRATION flag even
4342 * if mapcount goes down to 0. We can do remap successfully
4343 * without charging it again.
4346 * The "old" page is under lock_page() until the end of
4347 * migration, so, the old page itself will not be swapped-out.
4348 * If the new page is swapped out before end_migraton, our
4349 * hook to usual swap-out path will catch the event.
4352 SetPageCgroupMigration(pc
);
4354 unlock_page_cgroup(pc
);
4356 * If the page is not charged at this point,
4364 * We charge new page before it's used/mapped. So, even if unlock_page()
4365 * is called before end_migration, we can catch all events on this new
4366 * page. In the case new page is migrated but not remapped, new page's
4367 * mapcount will be finally 0 and we call uncharge in end_migration().
4370 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4372 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4374 * The page is committed to the memcg, but it's not actually
4375 * charged to the res_counter since we plan on replacing the
4376 * old one and only one page is going to be left afterwards.
4378 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4381 /* remove redundant charge if migration failed*/
4382 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4383 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4385 struct page
*used
, *unused
;
4386 struct page_cgroup
*pc
;
4392 if (!migration_ok
) {
4399 anon
= PageAnon(used
);
4400 __mem_cgroup_uncharge_common(unused
,
4401 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4402 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4404 css_put(&memcg
->css
);
4406 * We disallowed uncharge of pages under migration because mapcount
4407 * of the page goes down to zero, temporarly.
4408 * Clear the flag and check the page should be charged.
4410 pc
= lookup_page_cgroup(oldpage
);
4411 lock_page_cgroup(pc
);
4412 ClearPageCgroupMigration(pc
);
4413 unlock_page_cgroup(pc
);
4416 * If a page is a file cache, radix-tree replacement is very atomic
4417 * and we can skip this check. When it was an Anon page, its mapcount
4418 * goes down to 0. But because we added MIGRATION flage, it's not
4419 * uncharged yet. There are several case but page->mapcount check
4420 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4421 * check. (see prepare_charge() also)
4424 mem_cgroup_uncharge_page(used
);
4428 * At replace page cache, newpage is not under any memcg but it's on
4429 * LRU. So, this function doesn't touch res_counter but handles LRU
4430 * in correct way. Both pages are locked so we cannot race with uncharge.
4432 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4433 struct page
*newpage
)
4435 struct mem_cgroup
*memcg
= NULL
;
4436 struct page_cgroup
*pc
;
4437 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4439 if (mem_cgroup_disabled())
4442 pc
= lookup_page_cgroup(oldpage
);
4443 /* fix accounting on old pages */
4444 lock_page_cgroup(pc
);
4445 if (PageCgroupUsed(pc
)) {
4446 memcg
= pc
->mem_cgroup
;
4447 mem_cgroup_charge_statistics(memcg
, false, -1);
4448 ClearPageCgroupUsed(pc
);
4450 unlock_page_cgroup(pc
);
4453 * When called from shmem_replace_page(), in some cases the
4454 * oldpage has already been charged, and in some cases not.
4459 * Even if newpage->mapping was NULL before starting replacement,
4460 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4461 * LRU while we overwrite pc->mem_cgroup.
4463 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4466 #ifdef CONFIG_DEBUG_VM
4467 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4469 struct page_cgroup
*pc
;
4471 pc
= lookup_page_cgroup(page
);
4473 * Can be NULL while feeding pages into the page allocator for
4474 * the first time, i.e. during boot or memory hotplug;
4475 * or when mem_cgroup_disabled().
4477 if (likely(pc
) && PageCgroupUsed(pc
))
4482 bool mem_cgroup_bad_page_check(struct page
*page
)
4484 if (mem_cgroup_disabled())
4487 return lookup_page_cgroup_used(page
) != NULL
;
4490 void mem_cgroup_print_bad_page(struct page
*page
)
4492 struct page_cgroup
*pc
;
4494 pc
= lookup_page_cgroup_used(page
);
4496 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4497 pc
, pc
->flags
, pc
->mem_cgroup
);
4502 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4503 unsigned long long val
)
4506 u64 memswlimit
, memlimit
;
4508 int children
= mem_cgroup_count_children(memcg
);
4509 u64 curusage
, oldusage
;
4513 * For keeping hierarchical_reclaim simple, how long we should retry
4514 * is depends on callers. We set our retry-count to be function
4515 * of # of children which we should visit in this loop.
4517 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4519 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4522 while (retry_count
) {
4523 if (signal_pending(current
)) {
4528 * Rather than hide all in some function, I do this in
4529 * open coded manner. You see what this really does.
4530 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4532 mutex_lock(&set_limit_mutex
);
4533 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4534 if (memswlimit
< val
) {
4536 mutex_unlock(&set_limit_mutex
);
4540 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4544 ret
= res_counter_set_limit(&memcg
->res
, val
);
4546 if (memswlimit
== val
)
4547 memcg
->memsw_is_minimum
= true;
4549 memcg
->memsw_is_minimum
= false;
4551 mutex_unlock(&set_limit_mutex
);
4556 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4557 MEM_CGROUP_RECLAIM_SHRINK
);
4558 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4559 /* Usage is reduced ? */
4560 if (curusage
>= oldusage
)
4563 oldusage
= curusage
;
4565 if (!ret
&& enlarge
)
4566 memcg_oom_recover(memcg
);
4571 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4572 unsigned long long val
)
4575 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4576 int children
= mem_cgroup_count_children(memcg
);
4580 /* see mem_cgroup_resize_res_limit */
4581 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4582 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4583 while (retry_count
) {
4584 if (signal_pending(current
)) {
4589 * Rather than hide all in some function, I do this in
4590 * open coded manner. You see what this really does.
4591 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4593 mutex_lock(&set_limit_mutex
);
4594 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4595 if (memlimit
> val
) {
4597 mutex_unlock(&set_limit_mutex
);
4600 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4601 if (memswlimit
< val
)
4603 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4605 if (memlimit
== val
)
4606 memcg
->memsw_is_minimum
= true;
4608 memcg
->memsw_is_minimum
= false;
4610 mutex_unlock(&set_limit_mutex
);
4615 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4616 MEM_CGROUP_RECLAIM_NOSWAP
|
4617 MEM_CGROUP_RECLAIM_SHRINK
);
4618 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4619 /* Usage is reduced ? */
4620 if (curusage
>= oldusage
)
4623 oldusage
= curusage
;
4625 if (!ret
&& enlarge
)
4626 memcg_oom_recover(memcg
);
4630 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
4632 unsigned long *total_scanned
)
4634 unsigned long nr_reclaimed
= 0;
4635 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
4636 unsigned long reclaimed
;
4638 struct mem_cgroup_tree_per_zone
*mctz
;
4639 unsigned long long excess
;
4640 unsigned long nr_scanned
;
4645 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
4647 * This loop can run a while, specially if mem_cgroup's continuously
4648 * keep exceeding their soft limit and putting the system under
4655 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
4660 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
4661 gfp_mask
, &nr_scanned
);
4662 nr_reclaimed
+= reclaimed
;
4663 *total_scanned
+= nr_scanned
;
4664 spin_lock(&mctz
->lock
);
4667 * If we failed to reclaim anything from this memory cgroup
4668 * it is time to move on to the next cgroup
4674 * Loop until we find yet another one.
4676 * By the time we get the soft_limit lock
4677 * again, someone might have aded the
4678 * group back on the RB tree. Iterate to
4679 * make sure we get a different mem.
4680 * mem_cgroup_largest_soft_limit_node returns
4681 * NULL if no other cgroup is present on
4685 __mem_cgroup_largest_soft_limit_node(mctz
);
4687 css_put(&next_mz
->memcg
->css
);
4688 else /* next_mz == NULL or other memcg */
4692 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
4693 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
4695 * One school of thought says that we should not add
4696 * back the node to the tree if reclaim returns 0.
4697 * But our reclaim could return 0, simply because due
4698 * to priority we are exposing a smaller subset of
4699 * memory to reclaim from. Consider this as a longer
4702 /* If excess == 0, no tree ops */
4703 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
4704 spin_unlock(&mctz
->lock
);
4705 css_put(&mz
->memcg
->css
);
4708 * Could not reclaim anything and there are no more
4709 * mem cgroups to try or we seem to be looping without
4710 * reclaiming anything.
4712 if (!nr_reclaimed
&&
4714 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
4716 } while (!nr_reclaimed
);
4718 css_put(&next_mz
->memcg
->css
);
4719 return nr_reclaimed
;
4723 * mem_cgroup_force_empty_list - clears LRU of a group
4724 * @memcg: group to clear
4727 * @lru: lru to to clear
4729 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4730 * reclaim the pages page themselves - pages are moved to the parent (or root)
4733 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4734 int node
, int zid
, enum lru_list lru
)
4736 struct lruvec
*lruvec
;
4737 unsigned long flags
;
4738 struct list_head
*list
;
4742 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4743 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4744 list
= &lruvec
->lists
[lru
];
4748 struct page_cgroup
*pc
;
4751 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4752 if (list_empty(list
)) {
4753 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4756 page
= list_entry(list
->prev
, struct page
, lru
);
4758 list_move(&page
->lru
, list
);
4760 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4763 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4765 pc
= lookup_page_cgroup(page
);
4767 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4768 /* found lock contention or "pc" is obsolete. */
4773 } while (!list_empty(list
));
4777 * make mem_cgroup's charge to be 0 if there is no task by moving
4778 * all the charges and pages to the parent.
4779 * This enables deleting this mem_cgroup.
4781 * Caller is responsible for holding css reference on the memcg.
4783 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4789 /* This is for making all *used* pages to be on LRU. */
4790 lru_add_drain_all();
4791 drain_all_stock_sync(memcg
);
4792 mem_cgroup_start_move(memcg
);
4793 for_each_node_state(node
, N_MEMORY
) {
4794 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4797 mem_cgroup_force_empty_list(memcg
,
4802 mem_cgroup_end_move(memcg
);
4803 memcg_oom_recover(memcg
);
4807 * Kernel memory may not necessarily be trackable to a specific
4808 * process. So they are not migrated, and therefore we can't
4809 * expect their value to drop to 0 here.
4810 * Having res filled up with kmem only is enough.
4812 * This is a safety check because mem_cgroup_force_empty_list
4813 * could have raced with mem_cgroup_replace_page_cache callers
4814 * so the lru seemed empty but the page could have been added
4815 * right after the check. RES_USAGE should be safe as we always
4816 * charge before adding to the LRU.
4818 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
4819 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
4820 } while (usage
> 0);
4824 * This mainly exists for tests during the setting of set of use_hierarchy.
4825 * Since this is the very setting we are changing, the current hierarchy value
4828 static inline bool __memcg_has_children(struct mem_cgroup
*memcg
)
4832 /* bounce at first found */
4833 cgroup_for_each_child(pos
, memcg
->css
.cgroup
)
4839 * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed
4840 * to be already dead (as in mem_cgroup_force_empty, for instance). This is
4841 * from mem_cgroup_count_children(), in the sense that we don't really care how
4842 * many children we have; we only need to know if we have any. It also counts
4843 * any memcg without hierarchy as infertile.
4845 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
4847 return memcg
->use_hierarchy
&& __memcg_has_children(memcg
);
4851 * Reclaims as many pages from the given memcg as possible and moves
4852 * the rest to the parent.
4854 * Caller is responsible for holding css reference for memcg.
4856 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
4858 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
4859 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
4861 /* returns EBUSY if there is a task or if we come here twice. */
4862 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
4865 /* we call try-to-free pages for make this cgroup empty */
4866 lru_add_drain_all();
4867 /* try to free all pages in this cgroup */
4868 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
4871 if (signal_pending(current
))
4874 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
4878 /* maybe some writeback is necessary */
4879 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
4884 mem_cgroup_reparent_charges(memcg
);
4889 static int mem_cgroup_force_empty_write(struct cgroup
*cont
, unsigned int event
)
4891 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4894 if (mem_cgroup_is_root(memcg
))
4896 css_get(&memcg
->css
);
4897 ret
= mem_cgroup_force_empty(memcg
);
4898 css_put(&memcg
->css
);
4904 static u64
mem_cgroup_hierarchy_read(struct cgroup
*cont
, struct cftype
*cft
)
4906 return mem_cgroup_from_cont(cont
)->use_hierarchy
;
4909 static int mem_cgroup_hierarchy_write(struct cgroup
*cont
, struct cftype
*cft
,
4913 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4914 struct cgroup
*parent
= cont
->parent
;
4915 struct mem_cgroup
*parent_memcg
= NULL
;
4918 parent_memcg
= mem_cgroup_from_cont(parent
);
4920 mutex_lock(&memcg_create_mutex
);
4922 if (memcg
->use_hierarchy
== val
)
4926 * If parent's use_hierarchy is set, we can't make any modifications
4927 * in the child subtrees. If it is unset, then the change can
4928 * occur, provided the current cgroup has no children.
4930 * For the root cgroup, parent_mem is NULL, we allow value to be
4931 * set if there are no children.
4933 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
4934 (val
== 1 || val
== 0)) {
4935 if (!__memcg_has_children(memcg
))
4936 memcg
->use_hierarchy
= val
;
4943 mutex_unlock(&memcg_create_mutex
);
4949 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
4950 enum mem_cgroup_stat_index idx
)
4952 struct mem_cgroup
*iter
;
4955 /* Per-cpu values can be negative, use a signed accumulator */
4956 for_each_mem_cgroup_tree(iter
, memcg
)
4957 val
+= mem_cgroup_read_stat(iter
, idx
);
4959 if (val
< 0) /* race ? */
4964 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
4968 if (!mem_cgroup_is_root(memcg
)) {
4970 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4972 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4975 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
4976 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
4979 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
4981 return val
<< PAGE_SHIFT
;
4984 static ssize_t
mem_cgroup_read(struct cgroup
*cont
, struct cftype
*cft
,
4985 struct file
*file
, char __user
*buf
,
4986 size_t nbytes
, loff_t
*ppos
)
4988 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4994 type
= MEMFILE_TYPE(cft
->private);
4995 name
= MEMFILE_ATTR(cft
->private);
4997 if (!do_swap_account
&& type
== _MEMSWAP
)
5002 if (name
== RES_USAGE
)
5003 val
= mem_cgroup_usage(memcg
, false);
5005 val
= res_counter_read_u64(&memcg
->res
, name
);
5008 if (name
== RES_USAGE
)
5009 val
= mem_cgroup_usage(memcg
, true);
5011 val
= res_counter_read_u64(&memcg
->memsw
, name
);
5014 val
= res_counter_read_u64(&memcg
->kmem
, name
);
5020 len
= scnprintf(str
, sizeof(str
), "%llu\n", (unsigned long long)val
);
5021 return simple_read_from_buffer(buf
, nbytes
, ppos
, str
, len
);
5024 static int memcg_update_kmem_limit(struct cgroup
*cont
, u64 val
)
5027 #ifdef CONFIG_MEMCG_KMEM
5028 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5030 * For simplicity, we won't allow this to be disabled. It also can't
5031 * be changed if the cgroup has children already, or if tasks had
5034 * If tasks join before we set the limit, a person looking at
5035 * kmem.usage_in_bytes will have no way to determine when it took
5036 * place, which makes the value quite meaningless.
5038 * After it first became limited, changes in the value of the limit are
5039 * of course permitted.
5041 mutex_lock(&memcg_create_mutex
);
5042 mutex_lock(&set_limit_mutex
);
5043 if (!memcg
->kmem_account_flags
&& val
!= RESOURCE_MAX
) {
5044 if (cgroup_task_count(cont
) || memcg_has_children(memcg
)) {
5048 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5051 ret
= memcg_update_cache_sizes(memcg
);
5053 res_counter_set_limit(&memcg
->kmem
, RESOURCE_MAX
);
5056 static_key_slow_inc(&memcg_kmem_enabled_key
);
5058 * setting the active bit after the inc will guarantee no one
5059 * starts accounting before all call sites are patched
5061 memcg_kmem_set_active(memcg
);
5064 * kmem charges can outlive the cgroup. In the case of slab
5065 * pages, for instance, a page contain objects from various
5066 * processes, so it is unfeasible to migrate them away. We
5067 * need to reference count the memcg because of that.
5069 mem_cgroup_get(memcg
);
5071 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5073 mutex_unlock(&set_limit_mutex
);
5074 mutex_unlock(&memcg_create_mutex
);
5079 #ifdef CONFIG_MEMCG_KMEM
5080 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5083 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5087 memcg
->kmem_account_flags
= parent
->kmem_account_flags
;
5089 * When that happen, we need to disable the static branch only on those
5090 * memcgs that enabled it. To achieve this, we would be forced to
5091 * complicate the code by keeping track of which memcgs were the ones
5092 * that actually enabled limits, and which ones got it from its
5095 * It is a lot simpler just to do static_key_slow_inc() on every child
5096 * that is accounted.
5098 if (!memcg_kmem_is_active(memcg
))
5102 * destroy(), called if we fail, will issue static_key_slow_inc() and
5103 * mem_cgroup_put() if kmem is enabled. We have to either call them
5104 * unconditionally, or clear the KMEM_ACTIVE flag. I personally find
5105 * this more consistent, since it always leads to the same destroy path
5107 mem_cgroup_get(memcg
);
5108 static_key_slow_inc(&memcg_kmem_enabled_key
);
5110 mutex_lock(&set_limit_mutex
);
5111 ret
= memcg_update_cache_sizes(memcg
);
5112 mutex_unlock(&set_limit_mutex
);
5116 #endif /* CONFIG_MEMCG_KMEM */
5119 * The user of this function is...
5122 static int mem_cgroup_write(struct cgroup
*cont
, struct cftype
*cft
,
5125 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5128 unsigned long long val
;
5131 type
= MEMFILE_TYPE(cft
->private);
5132 name
= MEMFILE_ATTR(cft
->private);
5134 if (!do_swap_account
&& type
== _MEMSWAP
)
5139 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5143 /* This function does all necessary parse...reuse it */
5144 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5148 ret
= mem_cgroup_resize_limit(memcg
, val
);
5149 else if (type
== _MEMSWAP
)
5150 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5151 else if (type
== _KMEM
)
5152 ret
= memcg_update_kmem_limit(cont
, val
);
5156 case RES_SOFT_LIMIT
:
5157 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5161 * For memsw, soft limits are hard to implement in terms
5162 * of semantics, for now, we support soft limits for
5163 * control without swap
5166 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5171 ret
= -EINVAL
; /* should be BUG() ? */
5177 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5178 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5180 struct cgroup
*cgroup
;
5181 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5183 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5184 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5185 cgroup
= memcg
->css
.cgroup
;
5186 if (!memcg
->use_hierarchy
)
5189 while (cgroup
->parent
) {
5190 cgroup
= cgroup
->parent
;
5191 memcg
= mem_cgroup_from_cont(cgroup
);
5192 if (!memcg
->use_hierarchy
)
5194 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5195 min_limit
= min(min_limit
, tmp
);
5196 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5197 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5200 *mem_limit
= min_limit
;
5201 *memsw_limit
= min_memsw_limit
;
5204 static int mem_cgroup_reset(struct cgroup
*cont
, unsigned int event
)
5206 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5210 type
= MEMFILE_TYPE(event
);
5211 name
= MEMFILE_ATTR(event
);
5213 if (!do_swap_account
&& type
== _MEMSWAP
)
5219 res_counter_reset_max(&memcg
->res
);
5220 else if (type
== _MEMSWAP
)
5221 res_counter_reset_max(&memcg
->memsw
);
5222 else if (type
== _KMEM
)
5223 res_counter_reset_max(&memcg
->kmem
);
5229 res_counter_reset_failcnt(&memcg
->res
);
5230 else if (type
== _MEMSWAP
)
5231 res_counter_reset_failcnt(&memcg
->memsw
);
5232 else if (type
== _KMEM
)
5233 res_counter_reset_failcnt(&memcg
->kmem
);
5242 static u64
mem_cgroup_move_charge_read(struct cgroup
*cgrp
,
5245 return mem_cgroup_from_cont(cgrp
)->move_charge_at_immigrate
;
5249 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
5250 struct cftype
*cft
, u64 val
)
5252 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5254 if (val
>= (1 << NR_MOVE_TYPE
))
5258 * No kind of locking is needed in here, because ->can_attach() will
5259 * check this value once in the beginning of the process, and then carry
5260 * on with stale data. This means that changes to this value will only
5261 * affect task migrations starting after the change.
5263 memcg
->move_charge_at_immigrate
= val
;
5267 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
5268 struct cftype
*cft
, u64 val
)
5275 static int memcg_numa_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
5279 unsigned long total_nr
, file_nr
, anon_nr
, unevictable_nr
;
5280 unsigned long node_nr
;
5281 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5283 total_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL
);
5284 seq_printf(m
, "total=%lu", total_nr
);
5285 for_each_node_state(nid
, N_MEMORY
) {
5286 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL
);
5287 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5291 file_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_FILE
);
5292 seq_printf(m
, "file=%lu", file_nr
);
5293 for_each_node_state(nid
, N_MEMORY
) {
5294 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5296 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5300 anon_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_ANON
);
5301 seq_printf(m
, "anon=%lu", anon_nr
);
5302 for_each_node_state(nid
, N_MEMORY
) {
5303 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5305 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5309 unevictable_nr
= mem_cgroup_nr_lru_pages(memcg
, BIT(LRU_UNEVICTABLE
));
5310 seq_printf(m
, "unevictable=%lu", unevictable_nr
);
5311 for_each_node_state(nid
, N_MEMORY
) {
5312 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5313 BIT(LRU_UNEVICTABLE
));
5314 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5319 #endif /* CONFIG_NUMA */
5321 static inline void mem_cgroup_lru_names_not_uptodate(void)
5323 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5326 static int memcg_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
5329 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5330 struct mem_cgroup
*mi
;
5333 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5334 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5336 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5337 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5340 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5341 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5342 mem_cgroup_read_events(memcg
, i
));
5344 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5345 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5346 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5348 /* Hierarchical information */
5350 unsigned long long limit
, memsw_limit
;
5351 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5352 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5353 if (do_swap_account
)
5354 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5358 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5361 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5363 for_each_mem_cgroup_tree(mi
, memcg
)
5364 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5365 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5368 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5369 unsigned long long val
= 0;
5371 for_each_mem_cgroup_tree(mi
, memcg
)
5372 val
+= mem_cgroup_read_events(mi
, i
);
5373 seq_printf(m
, "total_%s %llu\n",
5374 mem_cgroup_events_names
[i
], val
);
5377 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5378 unsigned long long val
= 0;
5380 for_each_mem_cgroup_tree(mi
, memcg
)
5381 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5382 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5385 #ifdef CONFIG_DEBUG_VM
5388 struct mem_cgroup_per_zone
*mz
;
5389 struct zone_reclaim_stat
*rstat
;
5390 unsigned long recent_rotated
[2] = {0, 0};
5391 unsigned long recent_scanned
[2] = {0, 0};
5393 for_each_online_node(nid
)
5394 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5395 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5396 rstat
= &mz
->lruvec
.reclaim_stat
;
5398 recent_rotated
[0] += rstat
->recent_rotated
[0];
5399 recent_rotated
[1] += rstat
->recent_rotated
[1];
5400 recent_scanned
[0] += rstat
->recent_scanned
[0];
5401 recent_scanned
[1] += rstat
->recent_scanned
[1];
5403 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5404 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5405 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5406 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5413 static u64
mem_cgroup_swappiness_read(struct cgroup
*cgrp
, struct cftype
*cft
)
5415 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5417 return mem_cgroup_swappiness(memcg
);
5420 static int mem_cgroup_swappiness_write(struct cgroup
*cgrp
, struct cftype
*cft
,
5423 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5424 struct mem_cgroup
*parent
;
5429 if (cgrp
->parent
== NULL
)
5432 parent
= mem_cgroup_from_cont(cgrp
->parent
);
5434 mutex_lock(&memcg_create_mutex
);
5436 /* If under hierarchy, only empty-root can set this value */
5437 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5438 mutex_unlock(&memcg_create_mutex
);
5442 memcg
->swappiness
= val
;
5444 mutex_unlock(&memcg_create_mutex
);
5449 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5451 struct mem_cgroup_threshold_ary
*t
;
5457 t
= rcu_dereference(memcg
->thresholds
.primary
);
5459 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5464 usage
= mem_cgroup_usage(memcg
, swap
);
5467 * current_threshold points to threshold just below or equal to usage.
5468 * If it's not true, a threshold was crossed after last
5469 * call of __mem_cgroup_threshold().
5471 i
= t
->current_threshold
;
5474 * Iterate backward over array of thresholds starting from
5475 * current_threshold and check if a threshold is crossed.
5476 * If none of thresholds below usage is crossed, we read
5477 * only one element of the array here.
5479 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5480 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5482 /* i = current_threshold + 1 */
5486 * Iterate forward over array of thresholds starting from
5487 * current_threshold+1 and check if a threshold is crossed.
5488 * If none of thresholds above usage is crossed, we read
5489 * only one element of the array here.
5491 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5492 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5494 /* Update current_threshold */
5495 t
->current_threshold
= i
- 1;
5500 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5503 __mem_cgroup_threshold(memcg
, false);
5504 if (do_swap_account
)
5505 __mem_cgroup_threshold(memcg
, true);
5507 memcg
= parent_mem_cgroup(memcg
);
5511 static int compare_thresholds(const void *a
, const void *b
)
5513 const struct mem_cgroup_threshold
*_a
= a
;
5514 const struct mem_cgroup_threshold
*_b
= b
;
5516 return _a
->threshold
- _b
->threshold
;
5519 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5521 struct mem_cgroup_eventfd_list
*ev
;
5523 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5524 eventfd_signal(ev
->eventfd
, 1);
5528 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5530 struct mem_cgroup
*iter
;
5532 for_each_mem_cgroup_tree(iter
, memcg
)
5533 mem_cgroup_oom_notify_cb(iter
);
5536 static int mem_cgroup_usage_register_event(struct cgroup
*cgrp
,
5537 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5539 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5540 struct mem_cgroup_thresholds
*thresholds
;
5541 struct mem_cgroup_threshold_ary
*new;
5542 enum res_type type
= MEMFILE_TYPE(cft
->private);
5543 u64 threshold
, usage
;
5546 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5550 mutex_lock(&memcg
->thresholds_lock
);
5553 thresholds
= &memcg
->thresholds
;
5554 else if (type
== _MEMSWAP
)
5555 thresholds
= &memcg
->memsw_thresholds
;
5559 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5561 /* Check if a threshold crossed before adding a new one */
5562 if (thresholds
->primary
)
5563 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5565 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5567 /* Allocate memory for new array of thresholds */
5568 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5576 /* Copy thresholds (if any) to new array */
5577 if (thresholds
->primary
) {
5578 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5579 sizeof(struct mem_cgroup_threshold
));
5582 /* Add new threshold */
5583 new->entries
[size
- 1].eventfd
= eventfd
;
5584 new->entries
[size
- 1].threshold
= threshold
;
5586 /* Sort thresholds. Registering of new threshold isn't time-critical */
5587 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5588 compare_thresholds
, NULL
);
5590 /* Find current threshold */
5591 new->current_threshold
= -1;
5592 for (i
= 0; i
< size
; i
++) {
5593 if (new->entries
[i
].threshold
<= usage
) {
5595 * new->current_threshold will not be used until
5596 * rcu_assign_pointer(), so it's safe to increment
5599 ++new->current_threshold
;
5604 /* Free old spare buffer and save old primary buffer as spare */
5605 kfree(thresholds
->spare
);
5606 thresholds
->spare
= thresholds
->primary
;
5608 rcu_assign_pointer(thresholds
->primary
, new);
5610 /* To be sure that nobody uses thresholds */
5614 mutex_unlock(&memcg
->thresholds_lock
);
5619 static void mem_cgroup_usage_unregister_event(struct cgroup
*cgrp
,
5620 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5622 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5623 struct mem_cgroup_thresholds
*thresholds
;
5624 struct mem_cgroup_threshold_ary
*new;
5625 enum res_type type
= MEMFILE_TYPE(cft
->private);
5629 mutex_lock(&memcg
->thresholds_lock
);
5631 thresholds
= &memcg
->thresholds
;
5632 else if (type
== _MEMSWAP
)
5633 thresholds
= &memcg
->memsw_thresholds
;
5637 if (!thresholds
->primary
)
5640 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5642 /* Check if a threshold crossed before removing */
5643 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5645 /* Calculate new number of threshold */
5647 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5648 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5652 new = thresholds
->spare
;
5654 /* Set thresholds array to NULL if we don't have thresholds */
5663 /* Copy thresholds and find current threshold */
5664 new->current_threshold
= -1;
5665 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5666 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5669 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5670 if (new->entries
[j
].threshold
<= usage
) {
5672 * new->current_threshold will not be used
5673 * until rcu_assign_pointer(), so it's safe to increment
5676 ++new->current_threshold
;
5682 /* Swap primary and spare array */
5683 thresholds
->spare
= thresholds
->primary
;
5684 /* If all events are unregistered, free the spare array */
5686 kfree(thresholds
->spare
);
5687 thresholds
->spare
= NULL
;
5690 rcu_assign_pointer(thresholds
->primary
, new);
5692 /* To be sure that nobody uses thresholds */
5695 mutex_unlock(&memcg
->thresholds_lock
);
5698 static int mem_cgroup_oom_register_event(struct cgroup
*cgrp
,
5699 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5701 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5702 struct mem_cgroup_eventfd_list
*event
;
5703 enum res_type type
= MEMFILE_TYPE(cft
->private);
5705 BUG_ON(type
!= _OOM_TYPE
);
5706 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5710 spin_lock(&memcg_oom_lock
);
5712 event
->eventfd
= eventfd
;
5713 list_add(&event
->list
, &memcg
->oom_notify
);
5715 /* already in OOM ? */
5716 if (atomic_read(&memcg
->under_oom
))
5717 eventfd_signal(eventfd
, 1);
5718 spin_unlock(&memcg_oom_lock
);
5723 static void mem_cgroup_oom_unregister_event(struct cgroup
*cgrp
,
5724 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5726 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5727 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5728 enum res_type type
= MEMFILE_TYPE(cft
->private);
5730 BUG_ON(type
!= _OOM_TYPE
);
5732 spin_lock(&memcg_oom_lock
);
5734 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5735 if (ev
->eventfd
== eventfd
) {
5736 list_del(&ev
->list
);
5741 spin_unlock(&memcg_oom_lock
);
5744 static int mem_cgroup_oom_control_read(struct cgroup
*cgrp
,
5745 struct cftype
*cft
, struct cgroup_map_cb
*cb
)
5747 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5749 cb
->fill(cb
, "oom_kill_disable", memcg
->oom_kill_disable
);
5751 if (atomic_read(&memcg
->under_oom
))
5752 cb
->fill(cb
, "under_oom", 1);
5754 cb
->fill(cb
, "under_oom", 0);
5758 static int mem_cgroup_oom_control_write(struct cgroup
*cgrp
,
5759 struct cftype
*cft
, u64 val
)
5761 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5762 struct mem_cgroup
*parent
;
5764 /* cannot set to root cgroup and only 0 and 1 are allowed */
5765 if (!cgrp
->parent
|| !((val
== 0) || (val
== 1)))
5768 parent
= mem_cgroup_from_cont(cgrp
->parent
);
5770 mutex_lock(&memcg_create_mutex
);
5771 /* oom-kill-disable is a flag for subhierarchy. */
5772 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5773 mutex_unlock(&memcg_create_mutex
);
5776 memcg
->oom_kill_disable
= val
;
5778 memcg_oom_recover(memcg
);
5779 mutex_unlock(&memcg_create_mutex
);
5783 #ifdef CONFIG_MEMCG_KMEM
5784 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5788 memcg
->kmemcg_id
= -1;
5789 ret
= memcg_propagate_kmem(memcg
);
5793 return mem_cgroup_sockets_init(memcg
, ss
);
5796 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
5798 mem_cgroup_sockets_destroy(memcg
);
5800 memcg_kmem_mark_dead(memcg
);
5802 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5806 * Charges already down to 0, undo mem_cgroup_get() done in the charge
5807 * path here, being careful not to race with memcg_uncharge_kmem: it is
5808 * possible that the charges went down to 0 between mark_dead and the
5809 * res_counter read, so in that case, we don't need the put
5811 if (memcg_kmem_test_and_clear_dead(memcg
))
5812 mem_cgroup_put(memcg
);
5815 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5820 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
5825 static struct cftype mem_cgroup_files
[] = {
5827 .name
= "usage_in_bytes",
5828 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
5829 .read
= mem_cgroup_read
,
5830 .register_event
= mem_cgroup_usage_register_event
,
5831 .unregister_event
= mem_cgroup_usage_unregister_event
,
5834 .name
= "max_usage_in_bytes",
5835 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
5836 .trigger
= mem_cgroup_reset
,
5837 .read
= mem_cgroup_read
,
5840 .name
= "limit_in_bytes",
5841 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
5842 .write_string
= mem_cgroup_write
,
5843 .read
= mem_cgroup_read
,
5846 .name
= "soft_limit_in_bytes",
5847 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
5848 .write_string
= mem_cgroup_write
,
5849 .read
= mem_cgroup_read
,
5853 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
5854 .trigger
= mem_cgroup_reset
,
5855 .read
= mem_cgroup_read
,
5859 .read_seq_string
= memcg_stat_show
,
5862 .name
= "force_empty",
5863 .trigger
= mem_cgroup_force_empty_write
,
5866 .name
= "use_hierarchy",
5867 .write_u64
= mem_cgroup_hierarchy_write
,
5868 .read_u64
= mem_cgroup_hierarchy_read
,
5871 .name
= "swappiness",
5872 .read_u64
= mem_cgroup_swappiness_read
,
5873 .write_u64
= mem_cgroup_swappiness_write
,
5876 .name
= "move_charge_at_immigrate",
5877 .read_u64
= mem_cgroup_move_charge_read
,
5878 .write_u64
= mem_cgroup_move_charge_write
,
5881 .name
= "oom_control",
5882 .read_map
= mem_cgroup_oom_control_read
,
5883 .write_u64
= mem_cgroup_oom_control_write
,
5884 .register_event
= mem_cgroup_oom_register_event
,
5885 .unregister_event
= mem_cgroup_oom_unregister_event
,
5886 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
5890 .name
= "numa_stat",
5891 .read_seq_string
= memcg_numa_stat_show
,
5894 #ifdef CONFIG_MEMCG_KMEM
5896 .name
= "kmem.limit_in_bytes",
5897 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
5898 .write_string
= mem_cgroup_write
,
5899 .read
= mem_cgroup_read
,
5902 .name
= "kmem.usage_in_bytes",
5903 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
5904 .read
= mem_cgroup_read
,
5907 .name
= "kmem.failcnt",
5908 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
5909 .trigger
= mem_cgroup_reset
,
5910 .read
= mem_cgroup_read
,
5913 .name
= "kmem.max_usage_in_bytes",
5914 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
5915 .trigger
= mem_cgroup_reset
,
5916 .read
= mem_cgroup_read
,
5918 #ifdef CONFIG_SLABINFO
5920 .name
= "kmem.slabinfo",
5921 .read_seq_string
= mem_cgroup_slabinfo_read
,
5925 { }, /* terminate */
5928 #ifdef CONFIG_MEMCG_SWAP
5929 static struct cftype memsw_cgroup_files
[] = {
5931 .name
= "memsw.usage_in_bytes",
5932 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
5933 .read
= mem_cgroup_read
,
5934 .register_event
= mem_cgroup_usage_register_event
,
5935 .unregister_event
= mem_cgroup_usage_unregister_event
,
5938 .name
= "memsw.max_usage_in_bytes",
5939 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
5940 .trigger
= mem_cgroup_reset
,
5941 .read
= mem_cgroup_read
,
5944 .name
= "memsw.limit_in_bytes",
5945 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
5946 .write_string
= mem_cgroup_write
,
5947 .read
= mem_cgroup_read
,
5950 .name
= "memsw.failcnt",
5951 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
5952 .trigger
= mem_cgroup_reset
,
5953 .read
= mem_cgroup_read
,
5955 { }, /* terminate */
5958 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5960 struct mem_cgroup_per_node
*pn
;
5961 struct mem_cgroup_per_zone
*mz
;
5962 int zone
, tmp
= node
;
5964 * This routine is called against possible nodes.
5965 * But it's BUG to call kmalloc() against offline node.
5967 * TODO: this routine can waste much memory for nodes which will
5968 * never be onlined. It's better to use memory hotplug callback
5971 if (!node_state(node
, N_NORMAL_MEMORY
))
5973 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
5977 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
5980 mz
= &pn
->zoneinfo
[zone
];
5981 lruvec_init(&mz
->lruvec
);
5982 for (prio
= 0; prio
< DEF_PRIORITY
+ 1; prio
++)
5983 spin_lock_init(&mz
->reclaim_iter
[prio
].iter_lock
);
5984 mz
->usage_in_excess
= 0;
5985 mz
->on_tree
= false;
5988 memcg
->info
.nodeinfo
[node
] = pn
;
5992 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5994 kfree(memcg
->info
.nodeinfo
[node
]);
5997 static struct mem_cgroup
*mem_cgroup_alloc(void)
5999 struct mem_cgroup
*memcg
;
6000 size_t size
= memcg_size();
6002 /* Can be very big if nr_node_ids is very big */
6003 if (size
< PAGE_SIZE
)
6004 memcg
= kzalloc(size
, GFP_KERNEL
);
6006 memcg
= vzalloc(size
);
6011 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
6014 spin_lock_init(&memcg
->pcp_counter_lock
);
6018 if (size
< PAGE_SIZE
)
6026 * At destroying mem_cgroup, references from swap_cgroup can remain.
6027 * (scanning all at force_empty is too costly...)
6029 * Instead of clearing all references at force_empty, we remember
6030 * the number of reference from swap_cgroup and free mem_cgroup when
6031 * it goes down to 0.
6033 * Removal of cgroup itself succeeds regardless of refs from swap.
6036 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
6039 size_t size
= memcg_size();
6041 mem_cgroup_remove_from_trees(memcg
);
6042 free_css_id(&mem_cgroup_subsys
, &memcg
->css
);
6045 free_mem_cgroup_per_zone_info(memcg
, node
);
6047 free_percpu(memcg
->stat
);
6050 * We need to make sure that (at least for now), the jump label
6051 * destruction code runs outside of the cgroup lock. This is because
6052 * get_online_cpus(), which is called from the static_branch update,
6053 * can't be called inside the cgroup_lock. cpusets are the ones
6054 * enforcing this dependency, so if they ever change, we might as well.
6056 * schedule_work() will guarantee this happens. Be careful if you need
6057 * to move this code around, and make sure it is outside
6060 disarm_static_keys(memcg
);
6061 if (size
< PAGE_SIZE
)
6069 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
6070 * but in process context. The work_freeing structure is overlaid
6071 * on the rcu_freeing structure, which itself is overlaid on memsw.
6073 static void free_work(struct work_struct
*work
)
6075 struct mem_cgroup
*memcg
;
6077 memcg
= container_of(work
, struct mem_cgroup
, work_freeing
);
6078 __mem_cgroup_free(memcg
);
6081 static void free_rcu(struct rcu_head
*rcu_head
)
6083 struct mem_cgroup
*memcg
;
6085 memcg
= container_of(rcu_head
, struct mem_cgroup
, rcu_freeing
);
6086 INIT_WORK(&memcg
->work_freeing
, free_work
);
6087 schedule_work(&memcg
->work_freeing
);
6090 static void mem_cgroup_get(struct mem_cgroup
*memcg
)
6092 atomic_inc(&memcg
->refcnt
);
6095 static void __mem_cgroup_put(struct mem_cgroup
*memcg
, int count
)
6097 if (atomic_sub_and_test(count
, &memcg
->refcnt
)) {
6098 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
6099 call_rcu(&memcg
->rcu_freeing
, free_rcu
);
6101 mem_cgroup_put(parent
);
6105 static void mem_cgroup_put(struct mem_cgroup
*memcg
)
6107 __mem_cgroup_put(memcg
, 1);
6111 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6113 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6115 if (!memcg
->res
.parent
)
6117 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6119 EXPORT_SYMBOL(parent_mem_cgroup
);
6121 static void __init
mem_cgroup_soft_limit_tree_init(void)
6123 struct mem_cgroup_tree_per_node
*rtpn
;
6124 struct mem_cgroup_tree_per_zone
*rtpz
;
6125 int tmp
, node
, zone
;
6127 for_each_node(node
) {
6129 if (!node_state(node
, N_NORMAL_MEMORY
))
6131 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
6134 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6136 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6137 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
6138 rtpz
->rb_root
= RB_ROOT
;
6139 spin_lock_init(&rtpz
->lock
);
6144 static struct cgroup_subsys_state
* __ref
6145 mem_cgroup_css_alloc(struct cgroup
*cont
)
6147 struct mem_cgroup
*memcg
;
6148 long error
= -ENOMEM
;
6151 memcg
= mem_cgroup_alloc();
6153 return ERR_PTR(error
);
6156 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6160 if (cont
->parent
== NULL
) {
6161 root_mem_cgroup
= memcg
;
6162 res_counter_init(&memcg
->res
, NULL
);
6163 res_counter_init(&memcg
->memsw
, NULL
);
6164 res_counter_init(&memcg
->kmem
, NULL
);
6167 memcg
->last_scanned_node
= MAX_NUMNODES
;
6168 INIT_LIST_HEAD(&memcg
->oom_notify
);
6169 atomic_set(&memcg
->refcnt
, 1);
6170 memcg
->move_charge_at_immigrate
= 0;
6171 mutex_init(&memcg
->thresholds_lock
);
6172 spin_lock_init(&memcg
->move_lock
);
6177 __mem_cgroup_free(memcg
);
6178 return ERR_PTR(error
);
6182 mem_cgroup_css_online(struct cgroup
*cont
)
6184 struct mem_cgroup
*memcg
, *parent
;
6190 mutex_lock(&memcg_create_mutex
);
6191 memcg
= mem_cgroup_from_cont(cont
);
6192 parent
= mem_cgroup_from_cont(cont
->parent
);
6194 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6195 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6196 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6198 if (parent
->use_hierarchy
) {
6199 res_counter_init(&memcg
->res
, &parent
->res
);
6200 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6201 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6204 * We increment refcnt of the parent to ensure that we can
6205 * safely access it on res_counter_charge/uncharge.
6206 * This refcnt will be decremented when freeing this
6207 * mem_cgroup(see mem_cgroup_put).
6209 mem_cgroup_get(parent
);
6211 res_counter_init(&memcg
->res
, NULL
);
6212 res_counter_init(&memcg
->memsw
, NULL
);
6213 res_counter_init(&memcg
->kmem
, NULL
);
6215 * Deeper hierachy with use_hierarchy == false doesn't make
6216 * much sense so let cgroup subsystem know about this
6217 * unfortunate state in our controller.
6219 if (parent
!= root_mem_cgroup
)
6220 mem_cgroup_subsys
.broken_hierarchy
= true;
6223 error
= memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
6224 mutex_unlock(&memcg_create_mutex
);
6227 * We call put now because our (and parent's) refcnts
6228 * are already in place. mem_cgroup_put() will internally
6229 * call __mem_cgroup_free, so return directly
6231 mem_cgroup_put(memcg
);
6232 if (parent
->use_hierarchy
)
6233 mem_cgroup_put(parent
);
6238 static void mem_cgroup_css_offline(struct cgroup
*cont
)
6240 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
6242 mem_cgroup_reparent_charges(memcg
);
6243 mem_cgroup_destroy_all_caches(memcg
);
6246 static void mem_cgroup_css_free(struct cgroup
*cont
)
6248 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
6250 kmem_cgroup_destroy(memcg
);
6252 mem_cgroup_put(memcg
);
6256 /* Handlers for move charge at task migration. */
6257 #define PRECHARGE_COUNT_AT_ONCE 256
6258 static int mem_cgroup_do_precharge(unsigned long count
)
6261 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6262 struct mem_cgroup
*memcg
= mc
.to
;
6264 if (mem_cgroup_is_root(memcg
)) {
6265 mc
.precharge
+= count
;
6266 /* we don't need css_get for root */
6269 /* try to charge at once */
6271 struct res_counter
*dummy
;
6273 * "memcg" cannot be under rmdir() because we've already checked
6274 * by cgroup_lock_live_cgroup() that it is not removed and we
6275 * are still under the same cgroup_mutex. So we can postpone
6278 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6280 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6281 PAGE_SIZE
* count
, &dummy
)) {
6282 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6285 mc
.precharge
+= count
;
6289 /* fall back to one by one charge */
6291 if (signal_pending(current
)) {
6295 if (!batch_count
--) {
6296 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6299 ret
= __mem_cgroup_try_charge(NULL
,
6300 GFP_KERNEL
, 1, &memcg
, false);
6302 /* mem_cgroup_clear_mc() will do uncharge later */
6310 * get_mctgt_type - get target type of moving charge
6311 * @vma: the vma the pte to be checked belongs
6312 * @addr: the address corresponding to the pte to be checked
6313 * @ptent: the pte to be checked
6314 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6317 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6318 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6319 * move charge. if @target is not NULL, the page is stored in target->page
6320 * with extra refcnt got(Callers should handle it).
6321 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6322 * target for charge migration. if @target is not NULL, the entry is stored
6325 * Called with pte lock held.
6332 enum mc_target_type
{
6338 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6339 unsigned long addr
, pte_t ptent
)
6341 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6343 if (!page
|| !page_mapped(page
))
6345 if (PageAnon(page
)) {
6346 /* we don't move shared anon */
6349 } else if (!move_file())
6350 /* we ignore mapcount for file pages */
6352 if (!get_page_unless_zero(page
))
6359 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6360 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6362 struct page
*page
= NULL
;
6363 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6365 if (!move_anon() || non_swap_entry(ent
))
6368 * Because lookup_swap_cache() updates some statistics counter,
6369 * we call find_get_page() with swapper_space directly.
6371 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6372 if (do_swap_account
)
6373 entry
->val
= ent
.val
;
6378 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6379 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6385 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6386 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6388 struct page
*page
= NULL
;
6389 struct address_space
*mapping
;
6392 if (!vma
->vm_file
) /* anonymous vma */
6397 mapping
= vma
->vm_file
->f_mapping
;
6398 if (pte_none(ptent
))
6399 pgoff
= linear_page_index(vma
, addr
);
6400 else /* pte_file(ptent) is true */
6401 pgoff
= pte_to_pgoff(ptent
);
6403 /* page is moved even if it's not RSS of this task(page-faulted). */
6404 page
= find_get_page(mapping
, pgoff
);
6407 /* shmem/tmpfs may report page out on swap: account for that too. */
6408 if (radix_tree_exceptional_entry(page
)) {
6409 swp_entry_t swap
= radix_to_swp_entry(page
);
6410 if (do_swap_account
)
6412 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6418 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6419 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6421 struct page
*page
= NULL
;
6422 struct page_cgroup
*pc
;
6423 enum mc_target_type ret
= MC_TARGET_NONE
;
6424 swp_entry_t ent
= { .val
= 0 };
6426 if (pte_present(ptent
))
6427 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6428 else if (is_swap_pte(ptent
))
6429 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6430 else if (pte_none(ptent
) || pte_file(ptent
))
6431 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6433 if (!page
&& !ent
.val
)
6436 pc
= lookup_page_cgroup(page
);
6438 * Do only loose check w/o page_cgroup lock.
6439 * mem_cgroup_move_account() checks the pc is valid or not under
6442 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6443 ret
= MC_TARGET_PAGE
;
6445 target
->page
= page
;
6447 if (!ret
|| !target
)
6450 /* There is a swap entry and a page doesn't exist or isn't charged */
6451 if (ent
.val
&& !ret
&&
6452 css_id(&mc
.from
->css
) == lookup_swap_cgroup_id(ent
)) {
6453 ret
= MC_TARGET_SWAP
;
6460 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6462 * We don't consider swapping or file mapped pages because THP does not
6463 * support them for now.
6464 * Caller should make sure that pmd_trans_huge(pmd) is true.
6466 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6467 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6469 struct page
*page
= NULL
;
6470 struct page_cgroup
*pc
;
6471 enum mc_target_type ret
= MC_TARGET_NONE
;
6473 page
= pmd_page(pmd
);
6474 VM_BUG_ON(!page
|| !PageHead(page
));
6477 pc
= lookup_page_cgroup(page
);
6478 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6479 ret
= MC_TARGET_PAGE
;
6482 target
->page
= page
;
6488 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6489 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6491 return MC_TARGET_NONE
;
6495 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6496 unsigned long addr
, unsigned long end
,
6497 struct mm_walk
*walk
)
6499 struct vm_area_struct
*vma
= walk
->private;
6503 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6504 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6505 mc
.precharge
+= HPAGE_PMD_NR
;
6506 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6510 if (pmd_trans_unstable(pmd
))
6512 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6513 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6514 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6515 mc
.precharge
++; /* increment precharge temporarily */
6516 pte_unmap_unlock(pte
- 1, ptl
);
6522 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6524 unsigned long precharge
;
6525 struct vm_area_struct
*vma
;
6527 down_read(&mm
->mmap_sem
);
6528 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6529 struct mm_walk mem_cgroup_count_precharge_walk
= {
6530 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6534 if (is_vm_hugetlb_page(vma
))
6536 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6537 &mem_cgroup_count_precharge_walk
);
6539 up_read(&mm
->mmap_sem
);
6541 precharge
= mc
.precharge
;
6547 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6549 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6551 VM_BUG_ON(mc
.moving_task
);
6552 mc
.moving_task
= current
;
6553 return mem_cgroup_do_precharge(precharge
);
6556 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6557 static void __mem_cgroup_clear_mc(void)
6559 struct mem_cgroup
*from
= mc
.from
;
6560 struct mem_cgroup
*to
= mc
.to
;
6562 /* we must uncharge all the leftover precharges from mc.to */
6564 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6568 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6569 * we must uncharge here.
6571 if (mc
.moved_charge
) {
6572 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6573 mc
.moved_charge
= 0;
6575 /* we must fixup refcnts and charges */
6576 if (mc
.moved_swap
) {
6577 /* uncharge swap account from the old cgroup */
6578 if (!mem_cgroup_is_root(mc
.from
))
6579 res_counter_uncharge(&mc
.from
->memsw
,
6580 PAGE_SIZE
* mc
.moved_swap
);
6581 __mem_cgroup_put(mc
.from
, mc
.moved_swap
);
6583 if (!mem_cgroup_is_root(mc
.to
)) {
6585 * we charged both to->res and to->memsw, so we should
6588 res_counter_uncharge(&mc
.to
->res
,
6589 PAGE_SIZE
* mc
.moved_swap
);
6591 /* we've already done mem_cgroup_get(mc.to) */
6594 memcg_oom_recover(from
);
6595 memcg_oom_recover(to
);
6596 wake_up_all(&mc
.waitq
);
6599 static void mem_cgroup_clear_mc(void)
6601 struct mem_cgroup
*from
= mc
.from
;
6604 * we must clear moving_task before waking up waiters at the end of
6607 mc
.moving_task
= NULL
;
6608 __mem_cgroup_clear_mc();
6609 spin_lock(&mc
.lock
);
6612 spin_unlock(&mc
.lock
);
6613 mem_cgroup_end_move(from
);
6616 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
6617 struct cgroup_taskset
*tset
)
6619 struct task_struct
*p
= cgroup_taskset_first(tset
);
6621 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgroup
);
6622 unsigned long move_charge_at_immigrate
;
6625 * We are now commited to this value whatever it is. Changes in this
6626 * tunable will only affect upcoming migrations, not the current one.
6627 * So we need to save it, and keep it going.
6629 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
6630 if (move_charge_at_immigrate
) {
6631 struct mm_struct
*mm
;
6632 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
6634 VM_BUG_ON(from
== memcg
);
6636 mm
= get_task_mm(p
);
6639 /* We move charges only when we move a owner of the mm */
6640 if (mm
->owner
== p
) {
6643 VM_BUG_ON(mc
.precharge
);
6644 VM_BUG_ON(mc
.moved_charge
);
6645 VM_BUG_ON(mc
.moved_swap
);
6646 mem_cgroup_start_move(from
);
6647 spin_lock(&mc
.lock
);
6650 mc
.immigrate_flags
= move_charge_at_immigrate
;
6651 spin_unlock(&mc
.lock
);
6652 /* We set mc.moving_task later */
6654 ret
= mem_cgroup_precharge_mc(mm
);
6656 mem_cgroup_clear_mc();
6663 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
6664 struct cgroup_taskset
*tset
)
6666 mem_cgroup_clear_mc();
6669 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
6670 unsigned long addr
, unsigned long end
,
6671 struct mm_walk
*walk
)
6674 struct vm_area_struct
*vma
= walk
->private;
6677 enum mc_target_type target_type
;
6678 union mc_target target
;
6680 struct page_cgroup
*pc
;
6683 * We don't take compound_lock() here but no race with splitting thp
6685 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6686 * under splitting, which means there's no concurrent thp split,
6687 * - if another thread runs into split_huge_page() just after we
6688 * entered this if-block, the thread must wait for page table lock
6689 * to be unlocked in __split_huge_page_splitting(), where the main
6690 * part of thp split is not executed yet.
6692 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6693 if (mc
.precharge
< HPAGE_PMD_NR
) {
6694 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6697 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
6698 if (target_type
== MC_TARGET_PAGE
) {
6700 if (!isolate_lru_page(page
)) {
6701 pc
= lookup_page_cgroup(page
);
6702 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
6703 pc
, mc
.from
, mc
.to
)) {
6704 mc
.precharge
-= HPAGE_PMD_NR
;
6705 mc
.moved_charge
+= HPAGE_PMD_NR
;
6707 putback_lru_page(page
);
6711 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6715 if (pmd_trans_unstable(pmd
))
6718 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6719 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
6720 pte_t ptent
= *(pte
++);
6726 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
6727 case MC_TARGET_PAGE
:
6729 if (isolate_lru_page(page
))
6731 pc
= lookup_page_cgroup(page
);
6732 if (!mem_cgroup_move_account(page
, 1, pc
,
6735 /* we uncharge from mc.from later. */
6738 putback_lru_page(page
);
6739 put
: /* get_mctgt_type() gets the page */
6742 case MC_TARGET_SWAP
:
6744 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
6746 /* we fixup refcnts and charges later. */
6754 pte_unmap_unlock(pte
- 1, ptl
);
6759 * We have consumed all precharges we got in can_attach().
6760 * We try charge one by one, but don't do any additional
6761 * charges to mc.to if we have failed in charge once in attach()
6764 ret
= mem_cgroup_do_precharge(1);
6772 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
6774 struct vm_area_struct
*vma
;
6776 lru_add_drain_all();
6778 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
6780 * Someone who are holding the mmap_sem might be waiting in
6781 * waitq. So we cancel all extra charges, wake up all waiters,
6782 * and retry. Because we cancel precharges, we might not be able
6783 * to move enough charges, but moving charge is a best-effort
6784 * feature anyway, so it wouldn't be a big problem.
6786 __mem_cgroup_clear_mc();
6790 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6792 struct mm_walk mem_cgroup_move_charge_walk
= {
6793 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
6797 if (is_vm_hugetlb_page(vma
))
6799 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
6800 &mem_cgroup_move_charge_walk
);
6803 * means we have consumed all precharges and failed in
6804 * doing additional charge. Just abandon here.
6808 up_read(&mm
->mmap_sem
);
6811 static void mem_cgroup_move_task(struct cgroup
*cont
,
6812 struct cgroup_taskset
*tset
)
6814 struct task_struct
*p
= cgroup_taskset_first(tset
);
6815 struct mm_struct
*mm
= get_task_mm(p
);
6819 mem_cgroup_move_charge(mm
);
6823 mem_cgroup_clear_mc();
6825 #else /* !CONFIG_MMU */
6826 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
6827 struct cgroup_taskset
*tset
)
6831 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
6832 struct cgroup_taskset
*tset
)
6835 static void mem_cgroup_move_task(struct cgroup
*cont
,
6836 struct cgroup_taskset
*tset
)
6841 struct cgroup_subsys mem_cgroup_subsys
= {
6843 .subsys_id
= mem_cgroup_subsys_id
,
6844 .css_alloc
= mem_cgroup_css_alloc
,
6845 .css_online
= mem_cgroup_css_online
,
6846 .css_offline
= mem_cgroup_css_offline
,
6847 .css_free
= mem_cgroup_css_free
,
6848 .can_attach
= mem_cgroup_can_attach
,
6849 .cancel_attach
= mem_cgroup_cancel_attach
,
6850 .attach
= mem_cgroup_move_task
,
6851 .base_cftypes
= mem_cgroup_files
,
6856 #ifdef CONFIG_MEMCG_SWAP
6857 static int __init
enable_swap_account(char *s
)
6859 /* consider enabled if no parameter or 1 is given */
6860 if (!strcmp(s
, "1"))
6861 really_do_swap_account
= 1;
6862 else if (!strcmp(s
, "0"))
6863 really_do_swap_account
= 0;
6866 __setup("swapaccount=", enable_swap_account
);
6868 static void __init
memsw_file_init(void)
6870 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys
, memsw_cgroup_files
));
6873 static void __init
enable_swap_cgroup(void)
6875 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6876 do_swap_account
= 1;
6882 static void __init
enable_swap_cgroup(void)
6888 * subsys_initcall() for memory controller.
6890 * Some parts like hotcpu_notifier() have to be initialized from this context
6891 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6892 * everything that doesn't depend on a specific mem_cgroup structure should
6893 * be initialized from here.
6895 static int __init
mem_cgroup_init(void)
6897 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
6898 enable_swap_cgroup();
6899 mem_cgroup_soft_limit_tree_init();
6903 subsys_initcall(mem_cgroup_init
);