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 /* css_id of the last scanned hierarchy member */
157 /* scan generation, increased every round-trip */
158 unsigned int generation
;
162 * per-zone information in memory controller.
164 struct mem_cgroup_per_zone
{
165 struct lruvec lruvec
;
166 unsigned long lru_size
[NR_LRU_LISTS
];
168 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
170 struct rb_node tree_node
; /* RB tree node */
171 unsigned long long usage_in_excess
;/* Set to the value by which */
172 /* the soft limit is exceeded*/
174 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
175 /* use container_of */
178 struct mem_cgroup_per_node
{
179 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
182 struct mem_cgroup_lru_info
{
183 struct mem_cgroup_per_node
*nodeinfo
[0];
187 * Cgroups above their limits are maintained in a RB-Tree, independent of
188 * their hierarchy representation
191 struct mem_cgroup_tree_per_zone
{
192 struct rb_root rb_root
;
196 struct mem_cgroup_tree_per_node
{
197 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
200 struct mem_cgroup_tree
{
201 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
204 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
206 struct mem_cgroup_threshold
{
207 struct eventfd_ctx
*eventfd
;
212 struct mem_cgroup_threshold_ary
{
213 /* An array index points to threshold just below or equal to usage. */
214 int current_threshold
;
215 /* Size of entries[] */
217 /* Array of thresholds */
218 struct mem_cgroup_threshold entries
[0];
221 struct mem_cgroup_thresholds
{
222 /* Primary thresholds array */
223 struct mem_cgroup_threshold_ary
*primary
;
225 * Spare threshold array.
226 * This is needed to make mem_cgroup_unregister_event() "never fail".
227 * It must be able to store at least primary->size - 1 entries.
229 struct mem_cgroup_threshold_ary
*spare
;
233 struct mem_cgroup_eventfd_list
{
234 struct list_head list
;
235 struct eventfd_ctx
*eventfd
;
238 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
239 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
242 * The memory controller data structure. The memory controller controls both
243 * page cache and RSS per cgroup. We would eventually like to provide
244 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
245 * to help the administrator determine what knobs to tune.
247 * TODO: Add a water mark for the memory controller. Reclaim will begin when
248 * we hit the water mark. May be even add a low water mark, such that
249 * no reclaim occurs from a cgroup at it's low water mark, this is
250 * a feature that will be implemented much later in the future.
253 struct cgroup_subsys_state css
;
255 * the counter to account for memory usage
257 struct res_counter res
;
261 * the counter to account for mem+swap usage.
263 struct res_counter memsw
;
266 * rcu_freeing is used only when freeing struct mem_cgroup,
267 * so put it into a union to avoid wasting more memory.
268 * It must be disjoint from the css field. It could be
269 * in a union with the res field, but res plays a much
270 * larger part in mem_cgroup life than memsw, and might
271 * be of interest, even at time of free, when debugging.
272 * So share rcu_head with the less interesting memsw.
274 struct rcu_head rcu_freeing
;
276 * We also need some space for a worker in deferred freeing.
277 * By the time we call it, rcu_freeing is no longer in use.
279 struct work_struct work_freeing
;
283 * the counter to account for kernel memory usage.
285 struct res_counter kmem
;
287 * Should the accounting and control be hierarchical, per subtree?
290 unsigned long kmem_account_flags
; /* See KMEM_ACCOUNTED_*, below */
298 /* OOM-Killer disable */
299 int oom_kill_disable
;
301 /* set when res.limit == memsw.limit */
302 bool memsw_is_minimum
;
304 /* protect arrays of thresholds */
305 struct mutex thresholds_lock
;
307 /* thresholds for memory usage. RCU-protected */
308 struct mem_cgroup_thresholds thresholds
;
310 /* thresholds for mem+swap usage. RCU-protected */
311 struct mem_cgroup_thresholds memsw_thresholds
;
313 /* For oom notifier event fd */
314 struct list_head oom_notify
;
317 * Should we move charges of a task when a task is moved into this
318 * mem_cgroup ? And what type of charges should we move ?
320 unsigned long move_charge_at_immigrate
;
322 * set > 0 if pages under this cgroup are moving to other cgroup.
324 atomic_t moving_account
;
325 /* taken only while moving_account > 0 */
326 spinlock_t move_lock
;
330 struct mem_cgroup_stat_cpu __percpu
*stat
;
332 * used when a cpu is offlined or other synchronizations
333 * See mem_cgroup_read_stat().
335 struct mem_cgroup_stat_cpu nocpu_base
;
336 spinlock_t pcp_counter_lock
;
338 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
339 struct tcp_memcontrol tcp_mem
;
341 #if defined(CONFIG_MEMCG_KMEM)
342 /* analogous to slab_common's slab_caches list. per-memcg */
343 struct list_head memcg_slab_caches
;
344 /* Not a spinlock, we can take a lot of time walking the list */
345 struct mutex slab_caches_mutex
;
346 /* Index in the kmem_cache->memcg_params->memcg_caches array */
350 int last_scanned_node
;
352 nodemask_t scan_nodes
;
353 atomic_t numainfo_events
;
354 atomic_t numainfo_updating
;
357 * Per cgroup active and inactive list, similar to the
358 * per zone LRU lists.
360 * WARNING: This has to be the last element of the struct. Don't
361 * add new fields after this point.
363 struct mem_cgroup_lru_info info
;
366 static size_t memcg_size(void)
368 return sizeof(struct mem_cgroup
) +
369 nr_node_ids
* sizeof(struct mem_cgroup_per_node
);
372 /* internal only representation about the status of kmem accounting. */
374 KMEM_ACCOUNTED_ACTIVE
= 0, /* accounted by this cgroup itself */
375 KMEM_ACCOUNTED_ACTIVATED
, /* static key enabled. */
376 KMEM_ACCOUNTED_DEAD
, /* dead memcg with pending kmem charges */
379 /* We account when limit is on, but only after call sites are patched */
380 #define KMEM_ACCOUNTED_MASK \
381 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
383 #ifdef CONFIG_MEMCG_KMEM
384 static inline void memcg_kmem_set_active(struct mem_cgroup
*memcg
)
386 set_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
389 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
391 return test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
394 static void memcg_kmem_set_activated(struct mem_cgroup
*memcg
)
396 set_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
399 static void memcg_kmem_clear_activated(struct mem_cgroup
*memcg
)
401 clear_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
404 static void memcg_kmem_mark_dead(struct mem_cgroup
*memcg
)
406 if (test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
))
407 set_bit(KMEM_ACCOUNTED_DEAD
, &memcg
->kmem_account_flags
);
410 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup
*memcg
)
412 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD
,
413 &memcg
->kmem_account_flags
);
417 /* Stuffs for move charges at task migration. */
419 * Types of charges to be moved. "move_charge_at_immitgrate" and
420 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
423 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
424 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
428 /* "mc" and its members are protected by cgroup_mutex */
429 static struct move_charge_struct
{
430 spinlock_t lock
; /* for from, to */
431 struct mem_cgroup
*from
;
432 struct mem_cgroup
*to
;
433 unsigned long immigrate_flags
;
434 unsigned long precharge
;
435 unsigned long moved_charge
;
436 unsigned long moved_swap
;
437 struct task_struct
*moving_task
; /* a task moving charges */
438 wait_queue_head_t waitq
; /* a waitq for other context */
440 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
441 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
444 static bool move_anon(void)
446 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
449 static bool move_file(void)
451 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
455 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
456 * limit reclaim to prevent infinite loops, if they ever occur.
458 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
459 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
462 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
463 MEM_CGROUP_CHARGE_TYPE_ANON
,
464 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
465 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
469 /* for encoding cft->private value on file */
477 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
478 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
479 #define MEMFILE_ATTR(val) ((val) & 0xffff)
480 /* Used for OOM nofiier */
481 #define OOM_CONTROL (0)
484 * Reclaim flags for mem_cgroup_hierarchical_reclaim
486 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
487 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
488 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
489 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
491 static void mem_cgroup_get(struct mem_cgroup
*memcg
);
492 static void mem_cgroup_put(struct mem_cgroup
*memcg
);
495 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
497 return container_of(s
, struct mem_cgroup
, css
);
500 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
502 return (memcg
== root_mem_cgroup
);
505 /* Writing them here to avoid exposing memcg's inner layout */
506 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
508 void sock_update_memcg(struct sock
*sk
)
510 if (mem_cgroup_sockets_enabled
) {
511 struct mem_cgroup
*memcg
;
512 struct cg_proto
*cg_proto
;
514 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
516 /* Socket cloning can throw us here with sk_cgrp already
517 * filled. It won't however, necessarily happen from
518 * process context. So the test for root memcg given
519 * the current task's memcg won't help us in this case.
521 * Respecting the original socket's memcg is a better
522 * decision in this case.
525 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
526 mem_cgroup_get(sk
->sk_cgrp
->memcg
);
531 memcg
= mem_cgroup_from_task(current
);
532 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
533 if (!mem_cgroup_is_root(memcg
) && memcg_proto_active(cg_proto
)) {
534 mem_cgroup_get(memcg
);
535 sk
->sk_cgrp
= cg_proto
;
540 EXPORT_SYMBOL(sock_update_memcg
);
542 void sock_release_memcg(struct sock
*sk
)
544 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
545 struct mem_cgroup
*memcg
;
546 WARN_ON(!sk
->sk_cgrp
->memcg
);
547 memcg
= sk
->sk_cgrp
->memcg
;
548 mem_cgroup_put(memcg
);
552 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
554 if (!memcg
|| mem_cgroup_is_root(memcg
))
557 return &memcg
->tcp_mem
.cg_proto
;
559 EXPORT_SYMBOL(tcp_proto_cgroup
);
561 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
563 if (!memcg_proto_activated(&memcg
->tcp_mem
.cg_proto
))
565 static_key_slow_dec(&memcg_socket_limit_enabled
);
568 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
573 #ifdef CONFIG_MEMCG_KMEM
575 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
576 * There are two main reasons for not using the css_id for this:
577 * 1) this works better in sparse environments, where we have a lot of memcgs,
578 * but only a few kmem-limited. Or also, if we have, for instance, 200
579 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
580 * 200 entry array for that.
582 * 2) In order not to violate the cgroup API, we would like to do all memory
583 * allocation in ->create(). At that point, we haven't yet allocated the
584 * css_id. Having a separate index prevents us from messing with the cgroup
587 * The current size of the caches array is stored in
588 * memcg_limited_groups_array_size. It will double each time we have to
591 static DEFINE_IDA(kmem_limited_groups
);
592 int memcg_limited_groups_array_size
;
595 * MIN_SIZE is different than 1, because we would like to avoid going through
596 * the alloc/free process all the time. In a small machine, 4 kmem-limited
597 * cgroups is a reasonable guess. In the future, it could be a parameter or
598 * tunable, but that is strictly not necessary.
600 * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get
601 * this constant directly from cgroup, but it is understandable that this is
602 * better kept as an internal representation in cgroup.c. In any case, the
603 * css_id space is not getting any smaller, and we don't have to necessarily
604 * increase ours as well if it increases.
606 #define MEMCG_CACHES_MIN_SIZE 4
607 #define MEMCG_CACHES_MAX_SIZE 65535
610 * A lot of the calls to the cache allocation functions are expected to be
611 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
612 * conditional to this static branch, we'll have to allow modules that does
613 * kmem_cache_alloc and the such to see this symbol as well
615 struct static_key memcg_kmem_enabled_key
;
616 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
618 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
620 if (memcg_kmem_is_active(memcg
)) {
621 static_key_slow_dec(&memcg_kmem_enabled_key
);
622 ida_simple_remove(&kmem_limited_groups
, memcg
->kmemcg_id
);
625 * This check can't live in kmem destruction function,
626 * since the charges will outlive the cgroup
628 WARN_ON(res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0);
631 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
634 #endif /* CONFIG_MEMCG_KMEM */
636 static void disarm_static_keys(struct mem_cgroup
*memcg
)
638 disarm_sock_keys(memcg
);
639 disarm_kmem_keys(memcg
);
642 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
644 static struct mem_cgroup_per_zone
*
645 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
647 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
648 return &memcg
->info
.nodeinfo
[nid
]->zoneinfo
[zid
];
651 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
656 static struct mem_cgroup_per_zone
*
657 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
659 int nid
= page_to_nid(page
);
660 int zid
= page_zonenum(page
);
662 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
665 static struct mem_cgroup_tree_per_zone
*
666 soft_limit_tree_node_zone(int nid
, int zid
)
668 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
671 static struct mem_cgroup_tree_per_zone
*
672 soft_limit_tree_from_page(struct page
*page
)
674 int nid
= page_to_nid(page
);
675 int zid
= page_zonenum(page
);
677 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
681 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
682 struct mem_cgroup_per_zone
*mz
,
683 struct mem_cgroup_tree_per_zone
*mctz
,
684 unsigned long long new_usage_in_excess
)
686 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
687 struct rb_node
*parent
= NULL
;
688 struct mem_cgroup_per_zone
*mz_node
;
693 mz
->usage_in_excess
= new_usage_in_excess
;
694 if (!mz
->usage_in_excess
)
698 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
700 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
703 * We can't avoid mem cgroups that are over their soft
704 * limit by the same amount
706 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
709 rb_link_node(&mz
->tree_node
, parent
, p
);
710 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
715 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
716 struct mem_cgroup_per_zone
*mz
,
717 struct mem_cgroup_tree_per_zone
*mctz
)
721 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
726 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
727 struct mem_cgroup_per_zone
*mz
,
728 struct mem_cgroup_tree_per_zone
*mctz
)
730 spin_lock(&mctz
->lock
);
731 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
732 spin_unlock(&mctz
->lock
);
736 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
738 unsigned long long excess
;
739 struct mem_cgroup_per_zone
*mz
;
740 struct mem_cgroup_tree_per_zone
*mctz
;
741 int nid
= page_to_nid(page
);
742 int zid
= page_zonenum(page
);
743 mctz
= soft_limit_tree_from_page(page
);
746 * Necessary to update all ancestors when hierarchy is used.
747 * because their event counter is not touched.
749 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
750 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
751 excess
= res_counter_soft_limit_excess(&memcg
->res
);
753 * We have to update the tree if mz is on RB-tree or
754 * mem is over its softlimit.
756 if (excess
|| mz
->on_tree
) {
757 spin_lock(&mctz
->lock
);
758 /* if on-tree, remove it */
760 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
762 * Insert again. mz->usage_in_excess will be updated.
763 * If excess is 0, no tree ops.
765 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
766 spin_unlock(&mctz
->lock
);
771 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
774 struct mem_cgroup_per_zone
*mz
;
775 struct mem_cgroup_tree_per_zone
*mctz
;
777 for_each_node(node
) {
778 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
779 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
780 mctz
= soft_limit_tree_node_zone(node
, zone
);
781 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
786 static struct mem_cgroup_per_zone
*
787 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
789 struct rb_node
*rightmost
= NULL
;
790 struct mem_cgroup_per_zone
*mz
;
794 rightmost
= rb_last(&mctz
->rb_root
);
796 goto done
; /* Nothing to reclaim from */
798 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
800 * Remove the node now but someone else can add it back,
801 * we will to add it back at the end of reclaim to its correct
802 * position in the tree.
804 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
805 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
806 !css_tryget(&mz
->memcg
->css
))
812 static struct mem_cgroup_per_zone
*
813 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
815 struct mem_cgroup_per_zone
*mz
;
817 spin_lock(&mctz
->lock
);
818 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
819 spin_unlock(&mctz
->lock
);
824 * Implementation Note: reading percpu statistics for memcg.
826 * Both of vmstat[] and percpu_counter has threshold and do periodic
827 * synchronization to implement "quick" read. There are trade-off between
828 * reading cost and precision of value. Then, we may have a chance to implement
829 * a periodic synchronizion of counter in memcg's counter.
831 * But this _read() function is used for user interface now. The user accounts
832 * memory usage by memory cgroup and he _always_ requires exact value because
833 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
834 * have to visit all online cpus and make sum. So, for now, unnecessary
835 * synchronization is not implemented. (just implemented for cpu hotplug)
837 * If there are kernel internal actions which can make use of some not-exact
838 * value, and reading all cpu value can be performance bottleneck in some
839 * common workload, threashold and synchonization as vmstat[] should be
842 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
843 enum mem_cgroup_stat_index idx
)
849 for_each_online_cpu(cpu
)
850 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
851 #ifdef CONFIG_HOTPLUG_CPU
852 spin_lock(&memcg
->pcp_counter_lock
);
853 val
+= memcg
->nocpu_base
.count
[idx
];
854 spin_unlock(&memcg
->pcp_counter_lock
);
860 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
863 int val
= (charge
) ? 1 : -1;
864 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
867 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
868 enum mem_cgroup_events_index idx
)
870 unsigned long val
= 0;
873 for_each_online_cpu(cpu
)
874 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
875 #ifdef CONFIG_HOTPLUG_CPU
876 spin_lock(&memcg
->pcp_counter_lock
);
877 val
+= memcg
->nocpu_base
.events
[idx
];
878 spin_unlock(&memcg
->pcp_counter_lock
);
883 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
884 bool anon
, int nr_pages
)
889 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
890 * counted as CACHE even if it's on ANON LRU.
893 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
896 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
899 /* pagein of a big page is an event. So, ignore page size */
901 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
903 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
904 nr_pages
= -nr_pages
; /* for event */
907 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
913 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
915 struct mem_cgroup_per_zone
*mz
;
917 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
918 return mz
->lru_size
[lru
];
922 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
923 unsigned int lru_mask
)
925 struct mem_cgroup_per_zone
*mz
;
927 unsigned long ret
= 0;
929 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
932 if (BIT(lru
) & lru_mask
)
933 ret
+= mz
->lru_size
[lru
];
939 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
940 int nid
, unsigned int lru_mask
)
945 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
946 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
952 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
953 unsigned int lru_mask
)
958 for_each_node_state(nid
, N_MEMORY
)
959 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
963 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
964 enum mem_cgroup_events_target target
)
966 unsigned long val
, next
;
968 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
969 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
970 /* from time_after() in jiffies.h */
971 if ((long)next
- (long)val
< 0) {
973 case MEM_CGROUP_TARGET_THRESH
:
974 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
976 case MEM_CGROUP_TARGET_SOFTLIMIT
:
977 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
979 case MEM_CGROUP_TARGET_NUMAINFO
:
980 next
= val
+ NUMAINFO_EVENTS_TARGET
;
985 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
992 * Check events in order.
995 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
998 /* threshold event is triggered in finer grain than soft limit */
999 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1000 MEM_CGROUP_TARGET_THRESH
))) {
1002 bool do_numainfo __maybe_unused
;
1004 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1005 MEM_CGROUP_TARGET_SOFTLIMIT
);
1006 #if MAX_NUMNODES > 1
1007 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1008 MEM_CGROUP_TARGET_NUMAINFO
);
1012 mem_cgroup_threshold(memcg
);
1013 if (unlikely(do_softlimit
))
1014 mem_cgroup_update_tree(memcg
, page
);
1015 #if MAX_NUMNODES > 1
1016 if (unlikely(do_numainfo
))
1017 atomic_inc(&memcg
->numainfo_events
);
1023 struct mem_cgroup
*mem_cgroup_from_cont(struct cgroup
*cont
)
1025 return mem_cgroup_from_css(
1026 cgroup_subsys_state(cont
, mem_cgroup_subsys_id
));
1029 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1032 * mm_update_next_owner() may clear mm->owner to NULL
1033 * if it races with swapoff, page migration, etc.
1034 * So this can be called with p == NULL.
1039 return mem_cgroup_from_css(task_subsys_state(p
, mem_cgroup_subsys_id
));
1042 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1044 struct mem_cgroup
*memcg
= NULL
;
1049 * Because we have no locks, mm->owner's may be being moved to other
1050 * cgroup. We use css_tryget() here even if this looks
1051 * pessimistic (rather than adding locks here).
1055 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1056 if (unlikely(!memcg
))
1058 } while (!css_tryget(&memcg
->css
));
1064 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1065 * @root: hierarchy root
1066 * @prev: previously returned memcg, NULL on first invocation
1067 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1069 * Returns references to children of the hierarchy below @root, or
1070 * @root itself, or %NULL after a full round-trip.
1072 * Caller must pass the return value in @prev on subsequent
1073 * invocations for reference counting, or use mem_cgroup_iter_break()
1074 * to cancel a hierarchy walk before the round-trip is complete.
1076 * Reclaimers can specify a zone and a priority level in @reclaim to
1077 * divide up the memcgs in the hierarchy among all concurrent
1078 * reclaimers operating on the same zone and priority.
1080 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1081 struct mem_cgroup
*prev
,
1082 struct mem_cgroup_reclaim_cookie
*reclaim
)
1084 struct mem_cgroup
*memcg
= NULL
;
1087 if (mem_cgroup_disabled())
1091 root
= root_mem_cgroup
;
1093 if (prev
&& !reclaim
)
1094 id
= css_id(&prev
->css
);
1096 if (prev
&& prev
!= root
)
1097 css_put(&prev
->css
);
1099 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1106 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1107 struct cgroup_subsys_state
*css
;
1110 int nid
= zone_to_nid(reclaim
->zone
);
1111 int zid
= zone_idx(reclaim
->zone
);
1112 struct mem_cgroup_per_zone
*mz
;
1114 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1115 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1116 if (prev
&& reclaim
->generation
!= iter
->generation
)
1118 id
= iter
->position
;
1122 css
= css_get_next(&mem_cgroup_subsys
, id
+ 1, &root
->css
, &id
);
1124 if (css
== &root
->css
|| css_tryget(css
))
1125 memcg
= mem_cgroup_from_css(css
);
1131 iter
->position
= id
;
1134 else if (!prev
&& memcg
)
1135 reclaim
->generation
= iter
->generation
;
1145 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1146 * @root: hierarchy root
1147 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1149 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1150 struct mem_cgroup
*prev
)
1153 root
= root_mem_cgroup
;
1154 if (prev
&& prev
!= root
)
1155 css_put(&prev
->css
);
1159 * Iteration constructs for visiting all cgroups (under a tree). If
1160 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1161 * be used for reference counting.
1163 #define for_each_mem_cgroup_tree(iter, root) \
1164 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1166 iter = mem_cgroup_iter(root, iter, NULL))
1168 #define for_each_mem_cgroup(iter) \
1169 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1171 iter = mem_cgroup_iter(NULL, iter, NULL))
1173 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1175 struct mem_cgroup
*memcg
;
1178 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1179 if (unlikely(!memcg
))
1184 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1187 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1195 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1198 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1199 * @zone: zone of the wanted lruvec
1200 * @memcg: memcg of the wanted lruvec
1202 * Returns the lru list vector holding pages for the given @zone and
1203 * @mem. This can be the global zone lruvec, if the memory controller
1206 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1207 struct mem_cgroup
*memcg
)
1209 struct mem_cgroup_per_zone
*mz
;
1210 struct lruvec
*lruvec
;
1212 if (mem_cgroup_disabled()) {
1213 lruvec
= &zone
->lruvec
;
1217 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1218 lruvec
= &mz
->lruvec
;
1221 * Since a node can be onlined after the mem_cgroup was created,
1222 * we have to be prepared to initialize lruvec->zone here;
1223 * and if offlined then reonlined, we need to reinitialize it.
1225 if (unlikely(lruvec
->zone
!= zone
))
1226 lruvec
->zone
= zone
;
1231 * Following LRU functions are allowed to be used without PCG_LOCK.
1232 * Operations are called by routine of global LRU independently from memcg.
1233 * What we have to take care of here is validness of pc->mem_cgroup.
1235 * Changes to pc->mem_cgroup happens when
1238 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1239 * It is added to LRU before charge.
1240 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1241 * When moving account, the page is not on LRU. It's isolated.
1245 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1247 * @zone: zone of the page
1249 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1251 struct mem_cgroup_per_zone
*mz
;
1252 struct mem_cgroup
*memcg
;
1253 struct page_cgroup
*pc
;
1254 struct lruvec
*lruvec
;
1256 if (mem_cgroup_disabled()) {
1257 lruvec
= &zone
->lruvec
;
1261 pc
= lookup_page_cgroup(page
);
1262 memcg
= pc
->mem_cgroup
;
1265 * Surreptitiously switch any uncharged offlist page to root:
1266 * an uncharged page off lru does nothing to secure
1267 * its former mem_cgroup from sudden removal.
1269 * Our caller holds lru_lock, and PageCgroupUsed is updated
1270 * under page_cgroup lock: between them, they make all uses
1271 * of pc->mem_cgroup safe.
1273 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1274 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1276 mz
= page_cgroup_zoneinfo(memcg
, page
);
1277 lruvec
= &mz
->lruvec
;
1280 * Since a node can be onlined after the mem_cgroup was created,
1281 * we have to be prepared to initialize lruvec->zone here;
1282 * and if offlined then reonlined, we need to reinitialize it.
1284 if (unlikely(lruvec
->zone
!= zone
))
1285 lruvec
->zone
= zone
;
1290 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1291 * @lruvec: mem_cgroup per zone lru vector
1292 * @lru: index of lru list the page is sitting on
1293 * @nr_pages: positive when adding or negative when removing
1295 * This function must be called when a page is added to or removed from an
1298 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1301 struct mem_cgroup_per_zone
*mz
;
1302 unsigned long *lru_size
;
1304 if (mem_cgroup_disabled())
1307 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1308 lru_size
= mz
->lru_size
+ lru
;
1309 *lru_size
+= nr_pages
;
1310 VM_BUG_ON((long)(*lru_size
) < 0);
1314 * Checks whether given mem is same or in the root_mem_cgroup's
1317 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1318 struct mem_cgroup
*memcg
)
1320 if (root_memcg
== memcg
)
1322 if (!root_memcg
->use_hierarchy
|| !memcg
)
1324 return css_is_ancestor(&memcg
->css
, &root_memcg
->css
);
1327 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1328 struct mem_cgroup
*memcg
)
1333 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1338 int task_in_mem_cgroup(struct task_struct
*task
, const struct mem_cgroup
*memcg
)
1341 struct mem_cgroup
*curr
= NULL
;
1342 struct task_struct
*p
;
1344 p
= find_lock_task_mm(task
);
1346 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1350 * All threads may have already detached their mm's, but the oom
1351 * killer still needs to detect if they have already been oom
1352 * killed to prevent needlessly killing additional tasks.
1355 curr
= mem_cgroup_from_task(task
);
1357 css_get(&curr
->css
);
1363 * We should check use_hierarchy of "memcg" not "curr". Because checking
1364 * use_hierarchy of "curr" here make this function true if hierarchy is
1365 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1366 * hierarchy(even if use_hierarchy is disabled in "memcg").
1368 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1369 css_put(&curr
->css
);
1373 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1375 unsigned long inactive_ratio
;
1376 unsigned long inactive
;
1377 unsigned long active
;
1380 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1381 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1383 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1385 inactive_ratio
= int_sqrt(10 * gb
);
1389 return inactive
* inactive_ratio
< active
;
1392 int mem_cgroup_inactive_file_is_low(struct lruvec
*lruvec
)
1394 unsigned long active
;
1395 unsigned long inactive
;
1397 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_FILE
);
1398 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_FILE
);
1400 return (active
> inactive
);
1403 #define mem_cgroup_from_res_counter(counter, member) \
1404 container_of(counter, struct mem_cgroup, member)
1407 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1408 * @memcg: the memory cgroup
1410 * Returns the maximum amount of memory @mem can be charged with, in
1413 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1415 unsigned long long margin
;
1417 margin
= res_counter_margin(&memcg
->res
);
1418 if (do_swap_account
)
1419 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1420 return margin
>> PAGE_SHIFT
;
1423 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1425 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
1428 if (cgrp
->parent
== NULL
)
1429 return vm_swappiness
;
1431 return memcg
->swappiness
;
1435 * memcg->moving_account is used for checking possibility that some thread is
1436 * calling move_account(). When a thread on CPU-A starts moving pages under
1437 * a memcg, other threads should check memcg->moving_account under
1438 * rcu_read_lock(), like this:
1442 * memcg->moving_account+1 if (memcg->mocing_account)
1444 * synchronize_rcu() update something.
1449 /* for quick checking without looking up memcg */
1450 atomic_t memcg_moving __read_mostly
;
1452 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1454 atomic_inc(&memcg_moving
);
1455 atomic_inc(&memcg
->moving_account
);
1459 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1462 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1463 * We check NULL in callee rather than caller.
1466 atomic_dec(&memcg_moving
);
1467 atomic_dec(&memcg
->moving_account
);
1472 * 2 routines for checking "mem" is under move_account() or not.
1474 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1475 * is used for avoiding races in accounting. If true,
1476 * pc->mem_cgroup may be overwritten.
1478 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1479 * under hierarchy of moving cgroups. This is for
1480 * waiting at hith-memory prressure caused by "move".
1483 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1485 VM_BUG_ON(!rcu_read_lock_held());
1486 return atomic_read(&memcg
->moving_account
) > 0;
1489 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1491 struct mem_cgroup
*from
;
1492 struct mem_cgroup
*to
;
1495 * Unlike task_move routines, we access mc.to, mc.from not under
1496 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1498 spin_lock(&mc
.lock
);
1504 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1505 || mem_cgroup_same_or_subtree(memcg
, to
);
1507 spin_unlock(&mc
.lock
);
1511 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1513 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1514 if (mem_cgroup_under_move(memcg
)) {
1516 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1517 /* moving charge context might have finished. */
1520 finish_wait(&mc
.waitq
, &wait
);
1528 * Take this lock when
1529 * - a code tries to modify page's memcg while it's USED.
1530 * - a code tries to modify page state accounting in a memcg.
1531 * see mem_cgroup_stolen(), too.
1533 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1534 unsigned long *flags
)
1536 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1539 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1540 unsigned long *flags
)
1542 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1545 #define K(x) ((x) << (PAGE_SHIFT-10))
1547 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1548 * @memcg: The memory cgroup that went over limit
1549 * @p: Task that is going to be killed
1551 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1554 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1556 struct cgroup
*task_cgrp
;
1557 struct cgroup
*mem_cgrp
;
1559 * Need a buffer in BSS, can't rely on allocations. The code relies
1560 * on the assumption that OOM is serialized for memory controller.
1561 * If this assumption is broken, revisit this code.
1563 static char memcg_name
[PATH_MAX
];
1565 struct mem_cgroup
*iter
;
1573 mem_cgrp
= memcg
->css
.cgroup
;
1574 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1576 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1579 * Unfortunately, we are unable to convert to a useful name
1580 * But we'll still print out the usage information
1587 pr_info("Task in %s killed", memcg_name
);
1590 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1598 * Continues from above, so we don't need an KERN_ level
1600 pr_cont(" as a result of limit of %s\n", memcg_name
);
1603 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1604 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1605 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1606 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1607 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1608 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1609 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1610 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1611 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1612 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1613 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1614 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1616 for_each_mem_cgroup_tree(iter
, memcg
) {
1617 pr_info("Memory cgroup stats");
1620 ret
= cgroup_path(iter
->css
.cgroup
, memcg_name
, PATH_MAX
);
1622 pr_cont(" for %s", memcg_name
);
1626 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1627 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1629 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1630 K(mem_cgroup_read_stat(iter
, i
)));
1633 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1634 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1635 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1642 * This function returns the number of memcg under hierarchy tree. Returns
1643 * 1(self count) if no children.
1645 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1648 struct mem_cgroup
*iter
;
1650 for_each_mem_cgroup_tree(iter
, memcg
)
1656 * Return the memory (and swap, if configured) limit for a memcg.
1658 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1662 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1665 * Do not consider swap space if we cannot swap due to swappiness
1667 if (mem_cgroup_swappiness(memcg
)) {
1670 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1671 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1674 * If memsw is finite and limits the amount of swap space
1675 * available to this memcg, return that limit.
1677 limit
= min(limit
, memsw
);
1683 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1686 struct mem_cgroup
*iter
;
1687 unsigned long chosen_points
= 0;
1688 unsigned long totalpages
;
1689 unsigned int points
= 0;
1690 struct task_struct
*chosen
= NULL
;
1693 * If current has a pending SIGKILL, then automatically select it. The
1694 * goal is to allow it to allocate so that it may quickly exit and free
1697 if (fatal_signal_pending(current
)) {
1698 set_thread_flag(TIF_MEMDIE
);
1702 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1703 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1704 for_each_mem_cgroup_tree(iter
, memcg
) {
1705 struct cgroup
*cgroup
= iter
->css
.cgroup
;
1706 struct cgroup_iter it
;
1707 struct task_struct
*task
;
1709 cgroup_iter_start(cgroup
, &it
);
1710 while ((task
= cgroup_iter_next(cgroup
, &it
))) {
1711 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1713 case OOM_SCAN_SELECT
:
1715 put_task_struct(chosen
);
1717 chosen_points
= ULONG_MAX
;
1718 get_task_struct(chosen
);
1720 case OOM_SCAN_CONTINUE
:
1722 case OOM_SCAN_ABORT
:
1723 cgroup_iter_end(cgroup
, &it
);
1724 mem_cgroup_iter_break(memcg
, iter
);
1726 put_task_struct(chosen
);
1731 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1732 if (points
> chosen_points
) {
1734 put_task_struct(chosen
);
1736 chosen_points
= points
;
1737 get_task_struct(chosen
);
1740 cgroup_iter_end(cgroup
, &it
);
1745 points
= chosen_points
* 1000 / totalpages
;
1746 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1747 NULL
, "Memory cgroup out of memory");
1750 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1752 unsigned long flags
)
1754 unsigned long total
= 0;
1755 bool noswap
= false;
1758 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1760 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1763 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1765 drain_all_stock_async(memcg
);
1766 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1768 * Allow limit shrinkers, which are triggered directly
1769 * by userspace, to catch signals and stop reclaim
1770 * after minimal progress, regardless of the margin.
1772 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1774 if (mem_cgroup_margin(memcg
))
1777 * If nothing was reclaimed after two attempts, there
1778 * may be no reclaimable pages in this hierarchy.
1787 * test_mem_cgroup_node_reclaimable
1788 * @memcg: the target memcg
1789 * @nid: the node ID to be checked.
1790 * @noswap : specify true here if the user wants flle only information.
1792 * This function returns whether the specified memcg contains any
1793 * reclaimable pages on a node. Returns true if there are any reclaimable
1794 * pages in the node.
1796 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1797 int nid
, bool noswap
)
1799 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1801 if (noswap
|| !total_swap_pages
)
1803 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1808 #if MAX_NUMNODES > 1
1811 * Always updating the nodemask is not very good - even if we have an empty
1812 * list or the wrong list here, we can start from some node and traverse all
1813 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1816 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1820 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1821 * pagein/pageout changes since the last update.
1823 if (!atomic_read(&memcg
->numainfo_events
))
1825 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1828 /* make a nodemask where this memcg uses memory from */
1829 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1831 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1833 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1834 node_clear(nid
, memcg
->scan_nodes
);
1837 atomic_set(&memcg
->numainfo_events
, 0);
1838 atomic_set(&memcg
->numainfo_updating
, 0);
1842 * Selecting a node where we start reclaim from. Because what we need is just
1843 * reducing usage counter, start from anywhere is O,K. Considering
1844 * memory reclaim from current node, there are pros. and cons.
1846 * Freeing memory from current node means freeing memory from a node which
1847 * we'll use or we've used. So, it may make LRU bad. And if several threads
1848 * hit limits, it will see a contention on a node. But freeing from remote
1849 * node means more costs for memory reclaim because of memory latency.
1851 * Now, we use round-robin. Better algorithm is welcomed.
1853 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1857 mem_cgroup_may_update_nodemask(memcg
);
1858 node
= memcg
->last_scanned_node
;
1860 node
= next_node(node
, memcg
->scan_nodes
);
1861 if (node
== MAX_NUMNODES
)
1862 node
= first_node(memcg
->scan_nodes
);
1864 * We call this when we hit limit, not when pages are added to LRU.
1865 * No LRU may hold pages because all pages are UNEVICTABLE or
1866 * memcg is too small and all pages are not on LRU. In that case,
1867 * we use curret node.
1869 if (unlikely(node
== MAX_NUMNODES
))
1870 node
= numa_node_id();
1872 memcg
->last_scanned_node
= node
;
1877 * Check all nodes whether it contains reclaimable pages or not.
1878 * For quick scan, we make use of scan_nodes. This will allow us to skip
1879 * unused nodes. But scan_nodes is lazily updated and may not cotain
1880 * enough new information. We need to do double check.
1882 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1887 * quick check...making use of scan_node.
1888 * We can skip unused nodes.
1890 if (!nodes_empty(memcg
->scan_nodes
)) {
1891 for (nid
= first_node(memcg
->scan_nodes
);
1893 nid
= next_node(nid
, memcg
->scan_nodes
)) {
1895 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1900 * Check rest of nodes.
1902 for_each_node_state(nid
, N_MEMORY
) {
1903 if (node_isset(nid
, memcg
->scan_nodes
))
1905 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1912 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1917 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1919 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
1923 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1926 unsigned long *total_scanned
)
1928 struct mem_cgroup
*victim
= NULL
;
1931 unsigned long excess
;
1932 unsigned long nr_scanned
;
1933 struct mem_cgroup_reclaim_cookie reclaim
= {
1938 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
1941 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1946 * If we have not been able to reclaim
1947 * anything, it might because there are
1948 * no reclaimable pages under this hierarchy
1953 * We want to do more targeted reclaim.
1954 * excess >> 2 is not to excessive so as to
1955 * reclaim too much, nor too less that we keep
1956 * coming back to reclaim from this cgroup
1958 if (total
>= (excess
>> 2) ||
1959 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1964 if (!mem_cgroup_reclaimable(victim
, false))
1966 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
1968 *total_scanned
+= nr_scanned
;
1969 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
1972 mem_cgroup_iter_break(root_memcg
, victim
);
1977 * Check OOM-Killer is already running under our hierarchy.
1978 * If someone is running, return false.
1979 * Has to be called with memcg_oom_lock
1981 static bool mem_cgroup_oom_lock(struct mem_cgroup
*memcg
)
1983 struct mem_cgroup
*iter
, *failed
= NULL
;
1985 for_each_mem_cgroup_tree(iter
, memcg
) {
1986 if (iter
->oom_lock
) {
1988 * this subtree of our hierarchy is already locked
1989 * so we cannot give a lock.
1992 mem_cgroup_iter_break(memcg
, iter
);
1995 iter
->oom_lock
= true;
2002 * OK, we failed to lock the whole subtree so we have to clean up
2003 * what we set up to the failing subtree
2005 for_each_mem_cgroup_tree(iter
, memcg
) {
2006 if (iter
== failed
) {
2007 mem_cgroup_iter_break(memcg
, iter
);
2010 iter
->oom_lock
= false;
2016 * Has to be called with memcg_oom_lock
2018 static int mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2020 struct mem_cgroup
*iter
;
2022 for_each_mem_cgroup_tree(iter
, memcg
)
2023 iter
->oom_lock
= false;
2027 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2029 struct mem_cgroup
*iter
;
2031 for_each_mem_cgroup_tree(iter
, memcg
)
2032 atomic_inc(&iter
->under_oom
);
2035 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2037 struct mem_cgroup
*iter
;
2040 * When a new child is created while the hierarchy is under oom,
2041 * mem_cgroup_oom_lock() may not be called. We have to use
2042 * atomic_add_unless() here.
2044 for_each_mem_cgroup_tree(iter
, memcg
)
2045 atomic_add_unless(&iter
->under_oom
, -1, 0);
2048 static DEFINE_SPINLOCK(memcg_oom_lock
);
2049 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2051 struct oom_wait_info
{
2052 struct mem_cgroup
*memcg
;
2056 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2057 unsigned mode
, int sync
, void *arg
)
2059 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2060 struct mem_cgroup
*oom_wait_memcg
;
2061 struct oom_wait_info
*oom_wait_info
;
2063 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2064 oom_wait_memcg
= oom_wait_info
->memcg
;
2067 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2068 * Then we can use css_is_ancestor without taking care of RCU.
2070 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2071 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2073 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2076 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2078 /* for filtering, pass "memcg" as argument. */
2079 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2082 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2084 if (memcg
&& atomic_read(&memcg
->under_oom
))
2085 memcg_wakeup_oom(memcg
);
2089 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
2091 static bool mem_cgroup_handle_oom(struct mem_cgroup
*memcg
, gfp_t mask
,
2094 struct oom_wait_info owait
;
2095 bool locked
, need_to_kill
;
2097 owait
.memcg
= memcg
;
2098 owait
.wait
.flags
= 0;
2099 owait
.wait
.func
= memcg_oom_wake_function
;
2100 owait
.wait
.private = current
;
2101 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2102 need_to_kill
= true;
2103 mem_cgroup_mark_under_oom(memcg
);
2105 /* At first, try to OOM lock hierarchy under memcg.*/
2106 spin_lock(&memcg_oom_lock
);
2107 locked
= mem_cgroup_oom_lock(memcg
);
2109 * Even if signal_pending(), we can't quit charge() loop without
2110 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
2111 * under OOM is always welcomed, use TASK_KILLABLE here.
2113 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2114 if (!locked
|| memcg
->oom_kill_disable
)
2115 need_to_kill
= false;
2117 mem_cgroup_oom_notify(memcg
);
2118 spin_unlock(&memcg_oom_lock
);
2121 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2122 mem_cgroup_out_of_memory(memcg
, mask
, order
);
2125 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2127 spin_lock(&memcg_oom_lock
);
2129 mem_cgroup_oom_unlock(memcg
);
2130 memcg_wakeup_oom(memcg
);
2131 spin_unlock(&memcg_oom_lock
);
2133 mem_cgroup_unmark_under_oom(memcg
);
2135 if (test_thread_flag(TIF_MEMDIE
) || fatal_signal_pending(current
))
2137 /* Give chance to dying process */
2138 schedule_timeout_uninterruptible(1);
2143 * Currently used to update mapped file statistics, but the routine can be
2144 * generalized to update other statistics as well.
2146 * Notes: Race condition
2148 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2149 * it tends to be costly. But considering some conditions, we doesn't need
2150 * to do so _always_.
2152 * Considering "charge", lock_page_cgroup() is not required because all
2153 * file-stat operations happen after a page is attached to radix-tree. There
2154 * are no race with "charge".
2156 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2157 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2158 * if there are race with "uncharge". Statistics itself is properly handled
2161 * Considering "move", this is an only case we see a race. To make the race
2162 * small, we check mm->moving_account and detect there are possibility of race
2163 * If there is, we take a lock.
2166 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2167 bool *locked
, unsigned long *flags
)
2169 struct mem_cgroup
*memcg
;
2170 struct page_cgroup
*pc
;
2172 pc
= lookup_page_cgroup(page
);
2174 memcg
= pc
->mem_cgroup
;
2175 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2178 * If this memory cgroup is not under account moving, we don't
2179 * need to take move_lock_mem_cgroup(). Because we already hold
2180 * rcu_read_lock(), any calls to move_account will be delayed until
2181 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2183 if (!mem_cgroup_stolen(memcg
))
2186 move_lock_mem_cgroup(memcg
, flags
);
2187 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2188 move_unlock_mem_cgroup(memcg
, flags
);
2194 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2196 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2199 * It's guaranteed that pc->mem_cgroup never changes while
2200 * lock is held because a routine modifies pc->mem_cgroup
2201 * should take move_lock_mem_cgroup().
2203 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2206 void mem_cgroup_update_page_stat(struct page
*page
,
2207 enum mem_cgroup_page_stat_item idx
, int val
)
2209 struct mem_cgroup
*memcg
;
2210 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2211 unsigned long uninitialized_var(flags
);
2213 if (mem_cgroup_disabled())
2216 memcg
= pc
->mem_cgroup
;
2217 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2221 case MEMCG_NR_FILE_MAPPED
:
2222 idx
= MEM_CGROUP_STAT_FILE_MAPPED
;
2228 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2232 * size of first charge trial. "32" comes from vmscan.c's magic value.
2233 * TODO: maybe necessary to use big numbers in big irons.
2235 #define CHARGE_BATCH 32U
2236 struct memcg_stock_pcp
{
2237 struct mem_cgroup
*cached
; /* this never be root cgroup */
2238 unsigned int nr_pages
;
2239 struct work_struct work
;
2240 unsigned long flags
;
2241 #define FLUSHING_CACHED_CHARGE 0
2243 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2244 static DEFINE_MUTEX(percpu_charge_mutex
);
2247 * consume_stock: Try to consume stocked charge on this cpu.
2248 * @memcg: memcg to consume from.
2249 * @nr_pages: how many pages to charge.
2251 * The charges will only happen if @memcg matches the current cpu's memcg
2252 * stock, and at least @nr_pages are available in that stock. Failure to
2253 * service an allocation will refill the stock.
2255 * returns true if successful, false otherwise.
2257 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2259 struct memcg_stock_pcp
*stock
;
2262 if (nr_pages
> CHARGE_BATCH
)
2265 stock
= &get_cpu_var(memcg_stock
);
2266 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2267 stock
->nr_pages
-= nr_pages
;
2268 else /* need to call res_counter_charge */
2270 put_cpu_var(memcg_stock
);
2275 * Returns stocks cached in percpu to res_counter and reset cached information.
2277 static void drain_stock(struct memcg_stock_pcp
*stock
)
2279 struct mem_cgroup
*old
= stock
->cached
;
2281 if (stock
->nr_pages
) {
2282 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2284 res_counter_uncharge(&old
->res
, bytes
);
2285 if (do_swap_account
)
2286 res_counter_uncharge(&old
->memsw
, bytes
);
2287 stock
->nr_pages
= 0;
2289 stock
->cached
= NULL
;
2293 * This must be called under preempt disabled or must be called by
2294 * a thread which is pinned to local cpu.
2296 static void drain_local_stock(struct work_struct
*dummy
)
2298 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2300 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2304 * Cache charges(val) which is from res_counter, to local per_cpu area.
2305 * This will be consumed by consume_stock() function, later.
2307 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2309 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2311 if (stock
->cached
!= memcg
) { /* reset if necessary */
2313 stock
->cached
= memcg
;
2315 stock
->nr_pages
+= nr_pages
;
2316 put_cpu_var(memcg_stock
);
2320 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2321 * of the hierarchy under it. sync flag says whether we should block
2322 * until the work is done.
2324 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2328 /* Notify other cpus that system-wide "drain" is running */
2331 for_each_online_cpu(cpu
) {
2332 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2333 struct mem_cgroup
*memcg
;
2335 memcg
= stock
->cached
;
2336 if (!memcg
|| !stock
->nr_pages
)
2338 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2340 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2342 drain_local_stock(&stock
->work
);
2344 schedule_work_on(cpu
, &stock
->work
);
2352 for_each_online_cpu(cpu
) {
2353 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2354 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2355 flush_work(&stock
->work
);
2362 * Tries to drain stocked charges in other cpus. This function is asynchronous
2363 * and just put a work per cpu for draining localy on each cpu. Caller can
2364 * expects some charges will be back to res_counter later but cannot wait for
2367 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2370 * If someone calls draining, avoid adding more kworker runs.
2372 if (!mutex_trylock(&percpu_charge_mutex
))
2374 drain_all_stock(root_memcg
, false);
2375 mutex_unlock(&percpu_charge_mutex
);
2378 /* This is a synchronous drain interface. */
2379 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2381 /* called when force_empty is called */
2382 mutex_lock(&percpu_charge_mutex
);
2383 drain_all_stock(root_memcg
, true);
2384 mutex_unlock(&percpu_charge_mutex
);
2388 * This function drains percpu counter value from DEAD cpu and
2389 * move it to local cpu. Note that this function can be preempted.
2391 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2395 spin_lock(&memcg
->pcp_counter_lock
);
2396 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2397 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2399 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2400 memcg
->nocpu_base
.count
[i
] += x
;
2402 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2403 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2405 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2406 memcg
->nocpu_base
.events
[i
] += x
;
2408 spin_unlock(&memcg
->pcp_counter_lock
);
2411 static int __cpuinit
memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2412 unsigned long action
,
2415 int cpu
= (unsigned long)hcpu
;
2416 struct memcg_stock_pcp
*stock
;
2417 struct mem_cgroup
*iter
;
2419 if (action
== CPU_ONLINE
)
2422 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2425 for_each_mem_cgroup(iter
)
2426 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2428 stock
= &per_cpu(memcg_stock
, cpu
);
2434 /* See __mem_cgroup_try_charge() for details */
2436 CHARGE_OK
, /* success */
2437 CHARGE_RETRY
, /* need to retry but retry is not bad */
2438 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2439 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2440 CHARGE_OOM_DIE
, /* the current is killed because of OOM */
2443 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2444 unsigned int nr_pages
, unsigned int min_pages
,
2447 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2448 struct mem_cgroup
*mem_over_limit
;
2449 struct res_counter
*fail_res
;
2450 unsigned long flags
= 0;
2453 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2456 if (!do_swap_account
)
2458 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2462 res_counter_uncharge(&memcg
->res
, csize
);
2463 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2464 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2466 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2468 * Never reclaim on behalf of optional batching, retry with a
2469 * single page instead.
2471 if (nr_pages
> min_pages
)
2472 return CHARGE_RETRY
;
2474 if (!(gfp_mask
& __GFP_WAIT
))
2475 return CHARGE_WOULDBLOCK
;
2477 if (gfp_mask
& __GFP_NORETRY
)
2478 return CHARGE_NOMEM
;
2480 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2481 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2482 return CHARGE_RETRY
;
2484 * Even though the limit is exceeded at this point, reclaim
2485 * may have been able to free some pages. Retry the charge
2486 * before killing the task.
2488 * Only for regular pages, though: huge pages are rather
2489 * unlikely to succeed so close to the limit, and we fall back
2490 * to regular pages anyway in case of failure.
2492 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2493 return CHARGE_RETRY
;
2496 * At task move, charge accounts can be doubly counted. So, it's
2497 * better to wait until the end of task_move if something is going on.
2499 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2500 return CHARGE_RETRY
;
2502 /* If we don't need to call oom-killer at el, return immediately */
2504 return CHARGE_NOMEM
;
2506 if (!mem_cgroup_handle_oom(mem_over_limit
, gfp_mask
, get_order(csize
)))
2507 return CHARGE_OOM_DIE
;
2509 return CHARGE_RETRY
;
2513 * __mem_cgroup_try_charge() does
2514 * 1. detect memcg to be charged against from passed *mm and *ptr,
2515 * 2. update res_counter
2516 * 3. call memory reclaim if necessary.
2518 * In some special case, if the task is fatal, fatal_signal_pending() or
2519 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2520 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2521 * as possible without any hazards. 2: all pages should have a valid
2522 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2523 * pointer, that is treated as a charge to root_mem_cgroup.
2525 * So __mem_cgroup_try_charge() will return
2526 * 0 ... on success, filling *ptr with a valid memcg pointer.
2527 * -ENOMEM ... charge failure because of resource limits.
2528 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2530 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2531 * the oom-killer can be invoked.
2533 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2535 unsigned int nr_pages
,
2536 struct mem_cgroup
**ptr
,
2539 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2540 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2541 struct mem_cgroup
*memcg
= NULL
;
2545 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2546 * in system level. So, allow to go ahead dying process in addition to
2549 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2550 || fatal_signal_pending(current
)))
2554 * We always charge the cgroup the mm_struct belongs to.
2555 * The mm_struct's mem_cgroup changes on task migration if the
2556 * thread group leader migrates. It's possible that mm is not
2557 * set, if so charge the root memcg (happens for pagecache usage).
2560 *ptr
= root_mem_cgroup
;
2562 if (*ptr
) { /* css should be a valid one */
2564 if (mem_cgroup_is_root(memcg
))
2566 if (consume_stock(memcg
, nr_pages
))
2568 css_get(&memcg
->css
);
2570 struct task_struct
*p
;
2573 p
= rcu_dereference(mm
->owner
);
2575 * Because we don't have task_lock(), "p" can exit.
2576 * In that case, "memcg" can point to root or p can be NULL with
2577 * race with swapoff. Then, we have small risk of mis-accouning.
2578 * But such kind of mis-account by race always happens because
2579 * we don't have cgroup_mutex(). It's overkill and we allo that
2581 * (*) swapoff at el will charge against mm-struct not against
2582 * task-struct. So, mm->owner can be NULL.
2584 memcg
= mem_cgroup_from_task(p
);
2586 memcg
= root_mem_cgroup
;
2587 if (mem_cgroup_is_root(memcg
)) {
2591 if (consume_stock(memcg
, nr_pages
)) {
2593 * It seems dagerous to access memcg without css_get().
2594 * But considering how consume_stok works, it's not
2595 * necessary. If consume_stock success, some charges
2596 * from this memcg are cached on this cpu. So, we
2597 * don't need to call css_get()/css_tryget() before
2598 * calling consume_stock().
2603 /* after here, we may be blocked. we need to get refcnt */
2604 if (!css_tryget(&memcg
->css
)) {
2614 /* If killed, bypass charge */
2615 if (fatal_signal_pending(current
)) {
2616 css_put(&memcg
->css
);
2621 if (oom
&& !nr_oom_retries
) {
2623 nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2626 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
, nr_pages
,
2631 case CHARGE_RETRY
: /* not in OOM situation but retry */
2633 css_put(&memcg
->css
);
2636 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2637 css_put(&memcg
->css
);
2639 case CHARGE_NOMEM
: /* OOM routine works */
2641 css_put(&memcg
->css
);
2644 /* If oom, we never return -ENOMEM */
2647 case CHARGE_OOM_DIE
: /* Killed by OOM Killer */
2648 css_put(&memcg
->css
);
2651 } while (ret
!= CHARGE_OK
);
2653 if (batch
> nr_pages
)
2654 refill_stock(memcg
, batch
- nr_pages
);
2655 css_put(&memcg
->css
);
2663 *ptr
= root_mem_cgroup
;
2668 * Somemtimes we have to undo a charge we got by try_charge().
2669 * This function is for that and do uncharge, put css's refcnt.
2670 * gotten by try_charge().
2672 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2673 unsigned int nr_pages
)
2675 if (!mem_cgroup_is_root(memcg
)) {
2676 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2678 res_counter_uncharge(&memcg
->res
, bytes
);
2679 if (do_swap_account
)
2680 res_counter_uncharge(&memcg
->memsw
, bytes
);
2685 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2686 * This is useful when moving usage to parent cgroup.
2688 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2689 unsigned int nr_pages
)
2691 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2693 if (mem_cgroup_is_root(memcg
))
2696 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2697 if (do_swap_account
)
2698 res_counter_uncharge_until(&memcg
->memsw
,
2699 memcg
->memsw
.parent
, bytes
);
2703 * A helper function to get mem_cgroup from ID. must be called under
2704 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2705 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2706 * called against removed memcg.)
2708 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2710 struct cgroup_subsys_state
*css
;
2712 /* ID 0 is unused ID */
2715 css
= css_lookup(&mem_cgroup_subsys
, id
);
2718 return mem_cgroup_from_css(css
);
2721 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2723 struct mem_cgroup
*memcg
= NULL
;
2724 struct page_cgroup
*pc
;
2728 VM_BUG_ON(!PageLocked(page
));
2730 pc
= lookup_page_cgroup(page
);
2731 lock_page_cgroup(pc
);
2732 if (PageCgroupUsed(pc
)) {
2733 memcg
= pc
->mem_cgroup
;
2734 if (memcg
&& !css_tryget(&memcg
->css
))
2736 } else if (PageSwapCache(page
)) {
2737 ent
.val
= page_private(page
);
2738 id
= lookup_swap_cgroup_id(ent
);
2740 memcg
= mem_cgroup_lookup(id
);
2741 if (memcg
&& !css_tryget(&memcg
->css
))
2745 unlock_page_cgroup(pc
);
2749 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2751 unsigned int nr_pages
,
2752 enum charge_type ctype
,
2755 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2756 struct zone
*uninitialized_var(zone
);
2757 struct lruvec
*lruvec
;
2758 bool was_on_lru
= false;
2761 lock_page_cgroup(pc
);
2762 VM_BUG_ON(PageCgroupUsed(pc
));
2764 * we don't need page_cgroup_lock about tail pages, becase they are not
2765 * accessed by any other context at this point.
2769 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2770 * may already be on some other mem_cgroup's LRU. Take care of it.
2773 zone
= page_zone(page
);
2774 spin_lock_irq(&zone
->lru_lock
);
2775 if (PageLRU(page
)) {
2776 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2778 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2783 pc
->mem_cgroup
= memcg
;
2785 * We access a page_cgroup asynchronously without lock_page_cgroup().
2786 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2787 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2788 * before USED bit, we need memory barrier here.
2789 * See mem_cgroup_add_lru_list(), etc.
2792 SetPageCgroupUsed(pc
);
2796 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2797 VM_BUG_ON(PageLRU(page
));
2799 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2801 spin_unlock_irq(&zone
->lru_lock
);
2804 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2809 mem_cgroup_charge_statistics(memcg
, anon
, nr_pages
);
2810 unlock_page_cgroup(pc
);
2813 * "charge_statistics" updated event counter. Then, check it.
2814 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2815 * if they exceeds softlimit.
2817 memcg_check_events(memcg
, page
);
2820 static DEFINE_MUTEX(set_limit_mutex
);
2822 #ifdef CONFIG_MEMCG_KMEM
2823 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2825 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
2826 (memcg
->kmem_account_flags
& KMEM_ACCOUNTED_MASK
);
2830 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2831 * in the memcg_cache_params struct.
2833 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2835 struct kmem_cache
*cachep
;
2837 VM_BUG_ON(p
->is_root_cache
);
2838 cachep
= p
->root_cache
;
2839 return cachep
->memcg_params
->memcg_caches
[memcg_cache_id(p
->memcg
)];
2842 #ifdef CONFIG_SLABINFO
2843 static int mem_cgroup_slabinfo_read(struct cgroup
*cont
, struct cftype
*cft
,
2846 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
2847 struct memcg_cache_params
*params
;
2849 if (!memcg_can_account_kmem(memcg
))
2852 print_slabinfo_header(m
);
2854 mutex_lock(&memcg
->slab_caches_mutex
);
2855 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
2856 cache_show(memcg_params_to_cache(params
), m
);
2857 mutex_unlock(&memcg
->slab_caches_mutex
);
2863 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
2865 struct res_counter
*fail_res
;
2866 struct mem_cgroup
*_memcg
;
2870 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
2875 * Conditions under which we can wait for the oom_killer. Those are
2876 * the same conditions tested by the core page allocator
2878 may_oom
= (gfp
& __GFP_FS
) && !(gfp
& __GFP_NORETRY
);
2881 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
2884 if (ret
== -EINTR
) {
2886 * __mem_cgroup_try_charge() chosed to bypass to root due to
2887 * OOM kill or fatal signal. Since our only options are to
2888 * either fail the allocation or charge it to this cgroup, do
2889 * it as a temporary condition. But we can't fail. From a
2890 * kmem/slab perspective, the cache has already been selected,
2891 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2894 * This condition will only trigger if the task entered
2895 * memcg_charge_kmem in a sane state, but was OOM-killed during
2896 * __mem_cgroup_try_charge() above. Tasks that were already
2897 * dying when the allocation triggers should have been already
2898 * directed to the root cgroup in memcontrol.h
2900 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
2901 if (do_swap_account
)
2902 res_counter_charge_nofail(&memcg
->memsw
, size
,
2906 res_counter_uncharge(&memcg
->kmem
, size
);
2911 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
2913 res_counter_uncharge(&memcg
->res
, size
);
2914 if (do_swap_account
)
2915 res_counter_uncharge(&memcg
->memsw
, size
);
2918 if (res_counter_uncharge(&memcg
->kmem
, size
))
2921 if (memcg_kmem_test_and_clear_dead(memcg
))
2922 mem_cgroup_put(memcg
);
2925 void memcg_cache_list_add(struct mem_cgroup
*memcg
, struct kmem_cache
*cachep
)
2930 mutex_lock(&memcg
->slab_caches_mutex
);
2931 list_add(&cachep
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
2932 mutex_unlock(&memcg
->slab_caches_mutex
);
2936 * helper for acessing a memcg's index. It will be used as an index in the
2937 * child cache array in kmem_cache, and also to derive its name. This function
2938 * will return -1 when this is not a kmem-limited memcg.
2940 int memcg_cache_id(struct mem_cgroup
*memcg
)
2942 return memcg
? memcg
->kmemcg_id
: -1;
2946 * This ends up being protected by the set_limit mutex, during normal
2947 * operation, because that is its main call site.
2949 * But when we create a new cache, we can call this as well if its parent
2950 * is kmem-limited. That will have to hold set_limit_mutex as well.
2952 int memcg_update_cache_sizes(struct mem_cgroup
*memcg
)
2956 num
= ida_simple_get(&kmem_limited_groups
,
2957 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2961 * After this point, kmem_accounted (that we test atomically in
2962 * the beginning of this conditional), is no longer 0. This
2963 * guarantees only one process will set the following boolean
2964 * to true. We don't need test_and_set because we're protected
2965 * by the set_limit_mutex anyway.
2967 memcg_kmem_set_activated(memcg
);
2969 ret
= memcg_update_all_caches(num
+1);
2971 ida_simple_remove(&kmem_limited_groups
, num
);
2972 memcg_kmem_clear_activated(memcg
);
2976 memcg
->kmemcg_id
= num
;
2977 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
2978 mutex_init(&memcg
->slab_caches_mutex
);
2982 static size_t memcg_caches_array_size(int num_groups
)
2985 if (num_groups
<= 0)
2988 size
= 2 * num_groups
;
2989 if (size
< MEMCG_CACHES_MIN_SIZE
)
2990 size
= MEMCG_CACHES_MIN_SIZE
;
2991 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2992 size
= MEMCG_CACHES_MAX_SIZE
;
2998 * We should update the current array size iff all caches updates succeed. This
2999 * can only be done from the slab side. The slab mutex needs to be held when
3002 void memcg_update_array_size(int num
)
3004 if (num
> memcg_limited_groups_array_size
)
3005 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3008 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3010 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3012 VM_BUG_ON(s
->memcg_params
&& !s
->memcg_params
->is_root_cache
);
3014 if (num_groups
> memcg_limited_groups_array_size
) {
3016 ssize_t size
= memcg_caches_array_size(num_groups
);
3018 size
*= sizeof(void *);
3019 size
+= sizeof(struct memcg_cache_params
);
3021 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3022 if (!s
->memcg_params
) {
3023 s
->memcg_params
= cur_params
;
3027 s
->memcg_params
->is_root_cache
= true;
3030 * There is the chance it will be bigger than
3031 * memcg_limited_groups_array_size, if we failed an allocation
3032 * in a cache, in which case all caches updated before it, will
3033 * have a bigger array.
3035 * But if that is the case, the data after
3036 * memcg_limited_groups_array_size is certainly unused
3038 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3039 if (!cur_params
->memcg_caches
[i
])
3041 s
->memcg_params
->memcg_caches
[i
] =
3042 cur_params
->memcg_caches
[i
];
3046 * Ideally, we would wait until all caches succeed, and only
3047 * then free the old one. But this is not worth the extra
3048 * pointer per-cache we'd have to have for this.
3050 * It is not a big deal if some caches are left with a size
3051 * bigger than the others. And all updates will reset this
3059 int memcg_register_cache(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3060 struct kmem_cache
*root_cache
)
3062 size_t size
= sizeof(struct memcg_cache_params
);
3064 if (!memcg_kmem_enabled())
3068 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3070 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3071 if (!s
->memcg_params
)
3075 s
->memcg_params
->memcg
= memcg
;
3076 s
->memcg_params
->root_cache
= root_cache
;
3078 s
->memcg_params
->is_root_cache
= true;
3083 void memcg_release_cache(struct kmem_cache
*s
)
3085 struct kmem_cache
*root
;
3086 struct mem_cgroup
*memcg
;
3090 * This happens, for instance, when a root cache goes away before we
3093 if (!s
->memcg_params
)
3096 if (s
->memcg_params
->is_root_cache
)
3099 memcg
= s
->memcg_params
->memcg
;
3100 id
= memcg_cache_id(memcg
);
3102 root
= s
->memcg_params
->root_cache
;
3103 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3104 mem_cgroup_put(memcg
);
3106 mutex_lock(&memcg
->slab_caches_mutex
);
3107 list_del(&s
->memcg_params
->list
);
3108 mutex_unlock(&memcg
->slab_caches_mutex
);
3111 kfree(s
->memcg_params
);
3115 * During the creation a new cache, we need to disable our accounting mechanism
3116 * altogether. This is true even if we are not creating, but rather just
3117 * enqueing new caches to be created.
3119 * This is because that process will trigger allocations; some visible, like
3120 * explicit kmallocs to auxiliary data structures, name strings and internal
3121 * cache structures; some well concealed, like INIT_WORK() that can allocate
3122 * objects during debug.
3124 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3125 * to it. This may not be a bounded recursion: since the first cache creation
3126 * failed to complete (waiting on the allocation), we'll just try to create the
3127 * cache again, failing at the same point.
3129 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3130 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3131 * inside the following two functions.
3133 static inline void memcg_stop_kmem_account(void)
3135 VM_BUG_ON(!current
->mm
);
3136 current
->memcg_kmem_skip_account
++;
3139 static inline void memcg_resume_kmem_account(void)
3141 VM_BUG_ON(!current
->mm
);
3142 current
->memcg_kmem_skip_account
--;
3145 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3147 struct kmem_cache
*cachep
;
3148 struct memcg_cache_params
*p
;
3150 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3152 cachep
= memcg_params_to_cache(p
);
3155 * If we get down to 0 after shrink, we could delete right away.
3156 * However, memcg_release_pages() already puts us back in the workqueue
3157 * in that case. If we proceed deleting, we'll get a dangling
3158 * reference, and removing the object from the workqueue in that case
3159 * is unnecessary complication. We are not a fast path.
3161 * Note that this case is fundamentally different from racing with
3162 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3163 * kmem_cache_shrink, not only we would be reinserting a dead cache
3164 * into the queue, but doing so from inside the worker racing to
3167 * So if we aren't down to zero, we'll just schedule a worker and try
3170 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0) {
3171 kmem_cache_shrink(cachep
);
3172 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
3175 kmem_cache_destroy(cachep
);
3178 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3180 if (!cachep
->memcg_params
->dead
)
3184 * There are many ways in which we can get here.
3186 * We can get to a memory-pressure situation while the delayed work is
3187 * still pending to run. The vmscan shrinkers can then release all
3188 * cache memory and get us to destruction. If this is the case, we'll
3189 * be executed twice, which is a bug (the second time will execute over
3190 * bogus data). In this case, cancelling the work should be fine.
3192 * But we can also get here from the worker itself, if
3193 * kmem_cache_shrink is enough to shake all the remaining objects and
3194 * get the page count to 0. In this case, we'll deadlock if we try to
3195 * cancel the work (the worker runs with an internal lock held, which
3196 * is the same lock we would hold for cancel_work_sync().)
3198 * Since we can't possibly know who got us here, just refrain from
3199 * running if there is already work pending
3201 if (work_pending(&cachep
->memcg_params
->destroy
))
3204 * We have to defer the actual destroying to a workqueue, because
3205 * we might currently be in a context that cannot sleep.
3207 schedule_work(&cachep
->memcg_params
->destroy
);
3210 static char *memcg_cache_name(struct mem_cgroup
*memcg
, struct kmem_cache
*s
)
3213 struct dentry
*dentry
;
3216 dentry
= rcu_dereference(memcg
->css
.cgroup
->dentry
);
3219 BUG_ON(dentry
== NULL
);
3221 name
= kasprintf(GFP_KERNEL
, "%s(%d:%s)", s
->name
,
3222 memcg_cache_id(memcg
), dentry
->d_name
.name
);
3227 static struct kmem_cache
*kmem_cache_dup(struct mem_cgroup
*memcg
,
3228 struct kmem_cache
*s
)
3231 struct kmem_cache
*new;
3233 name
= memcg_cache_name(memcg
, s
);
3237 new = kmem_cache_create_memcg(memcg
, name
, s
->object_size
, s
->align
,
3238 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3241 new->allocflags
|= __GFP_KMEMCG
;
3248 * This lock protects updaters, not readers. We want readers to be as fast as
3249 * they can, and they will either see NULL or a valid cache value. Our model
3250 * allow them to see NULL, in which case the root memcg will be selected.
3252 * We need this lock because multiple allocations to the same cache from a non
3253 * will span more than one worker. Only one of them can create the cache.
3255 static DEFINE_MUTEX(memcg_cache_mutex
);
3256 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3257 struct kmem_cache
*cachep
)
3259 struct kmem_cache
*new_cachep
;
3262 BUG_ON(!memcg_can_account_kmem(memcg
));
3264 idx
= memcg_cache_id(memcg
);
3266 mutex_lock(&memcg_cache_mutex
);
3267 new_cachep
= cachep
->memcg_params
->memcg_caches
[idx
];
3271 new_cachep
= kmem_cache_dup(memcg
, cachep
);
3272 if (new_cachep
== NULL
) {
3273 new_cachep
= cachep
;
3277 mem_cgroup_get(memcg
);
3278 atomic_set(&new_cachep
->memcg_params
->nr_pages
, 0);
3280 cachep
->memcg_params
->memcg_caches
[idx
] = new_cachep
;
3282 * the readers won't lock, make sure everybody sees the updated value,
3283 * so they won't put stuff in the queue again for no reason
3287 mutex_unlock(&memcg_cache_mutex
);
3291 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3293 struct kmem_cache
*c
;
3296 if (!s
->memcg_params
)
3298 if (!s
->memcg_params
->is_root_cache
)
3302 * If the cache is being destroyed, we trust that there is no one else
3303 * requesting objects from it. Even if there are, the sanity checks in
3304 * kmem_cache_destroy should caught this ill-case.
3306 * Still, we don't want anyone else freeing memcg_caches under our
3307 * noses, which can happen if a new memcg comes to life. As usual,
3308 * we'll take the set_limit_mutex to protect ourselves against this.
3310 mutex_lock(&set_limit_mutex
);
3311 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3312 c
= s
->memcg_params
->memcg_caches
[i
];
3317 * We will now manually delete the caches, so to avoid races
3318 * we need to cancel all pending destruction workers and
3319 * proceed with destruction ourselves.
3321 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3322 * and that could spawn the workers again: it is likely that
3323 * the cache still have active pages until this very moment.
3324 * This would lead us back to mem_cgroup_destroy_cache.
3326 * But that will not execute at all if the "dead" flag is not
3327 * set, so flip it down to guarantee we are in control.
3329 c
->memcg_params
->dead
= false;
3330 cancel_work_sync(&c
->memcg_params
->destroy
);
3331 kmem_cache_destroy(c
);
3333 mutex_unlock(&set_limit_mutex
);
3336 struct create_work
{
3337 struct mem_cgroup
*memcg
;
3338 struct kmem_cache
*cachep
;
3339 struct work_struct work
;
3342 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3344 struct kmem_cache
*cachep
;
3345 struct memcg_cache_params
*params
;
3347 if (!memcg_kmem_is_active(memcg
))
3350 mutex_lock(&memcg
->slab_caches_mutex
);
3351 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3352 cachep
= memcg_params_to_cache(params
);
3353 cachep
->memcg_params
->dead
= true;
3354 INIT_WORK(&cachep
->memcg_params
->destroy
,
3355 kmem_cache_destroy_work_func
);
3356 schedule_work(&cachep
->memcg_params
->destroy
);
3358 mutex_unlock(&memcg
->slab_caches_mutex
);
3361 static void memcg_create_cache_work_func(struct work_struct
*w
)
3363 struct create_work
*cw
;
3365 cw
= container_of(w
, struct create_work
, work
);
3366 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3367 /* Drop the reference gotten when we enqueued. */
3368 css_put(&cw
->memcg
->css
);
3373 * Enqueue the creation of a per-memcg kmem_cache.
3374 * Called with rcu_read_lock.
3376 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3377 struct kmem_cache
*cachep
)
3379 struct create_work
*cw
;
3381 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3385 /* The corresponding put will be done in the workqueue. */
3386 if (!css_tryget(&memcg
->css
)) {
3392 cw
->cachep
= cachep
;
3394 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3395 schedule_work(&cw
->work
);
3398 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3399 struct kmem_cache
*cachep
)
3402 * We need to stop accounting when we kmalloc, because if the
3403 * corresponding kmalloc cache is not yet created, the first allocation
3404 * in __memcg_create_cache_enqueue will recurse.
3406 * However, it is better to enclose the whole function. Depending on
3407 * the debugging options enabled, INIT_WORK(), for instance, can
3408 * trigger an allocation. This too, will make us recurse. Because at
3409 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3410 * the safest choice is to do it like this, wrapping the whole function.
3412 memcg_stop_kmem_account();
3413 __memcg_create_cache_enqueue(memcg
, cachep
);
3414 memcg_resume_kmem_account();
3417 * Return the kmem_cache we're supposed to use for a slab allocation.
3418 * We try to use the current memcg's version of the cache.
3420 * If the cache does not exist yet, if we are the first user of it,
3421 * we either create it immediately, if possible, or create it asynchronously
3423 * In the latter case, we will let the current allocation go through with
3424 * the original cache.
3426 * Can't be called in interrupt context or from kernel threads.
3427 * This function needs to be called with rcu_read_lock() held.
3429 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3432 struct mem_cgroup
*memcg
;
3435 VM_BUG_ON(!cachep
->memcg_params
);
3436 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3438 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3442 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3445 if (!memcg_can_account_kmem(memcg
))
3448 idx
= memcg_cache_id(memcg
);
3451 * barrier to mare sure we're always seeing the up to date value. The
3452 * code updating memcg_caches will issue a write barrier to match this.
3454 read_barrier_depends();
3455 if (unlikely(cachep
->memcg_params
->memcg_caches
[idx
] == NULL
)) {
3457 * If we are in a safe context (can wait, and not in interrupt
3458 * context), we could be be predictable and return right away.
3459 * This would guarantee that the allocation being performed
3460 * already belongs in the new cache.
3462 * However, there are some clashes that can arrive from locking.
3463 * For instance, because we acquire the slab_mutex while doing
3464 * kmem_cache_dup, this means no further allocation could happen
3465 * with the slab_mutex held.
3467 * Also, because cache creation issue get_online_cpus(), this
3468 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3469 * that ends up reversed during cpu hotplug. (cpuset allocates
3470 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3471 * better to defer everything.
3473 memcg_create_cache_enqueue(memcg
, cachep
);
3477 return cachep
->memcg_params
->memcg_caches
[idx
];
3479 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3482 * We need to verify if the allocation against current->mm->owner's memcg is
3483 * possible for the given order. But the page is not allocated yet, so we'll
3484 * need a further commit step to do the final arrangements.
3486 * It is possible for the task to switch cgroups in this mean time, so at
3487 * commit time, we can't rely on task conversion any longer. We'll then use
3488 * the handle argument to return to the caller which cgroup we should commit
3489 * against. We could also return the memcg directly and avoid the pointer
3490 * passing, but a boolean return value gives better semantics considering
3491 * the compiled-out case as well.
3493 * Returning true means the allocation is possible.
3496 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3498 struct mem_cgroup
*memcg
;
3502 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3505 * very rare case described in mem_cgroup_from_task. Unfortunately there
3506 * isn't much we can do without complicating this too much, and it would
3507 * be gfp-dependent anyway. Just let it go
3509 if (unlikely(!memcg
))
3512 if (!memcg_can_account_kmem(memcg
)) {
3513 css_put(&memcg
->css
);
3517 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3521 css_put(&memcg
->css
);
3525 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3528 struct page_cgroup
*pc
;
3530 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3532 /* The page allocation failed. Revert */
3534 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3538 pc
= lookup_page_cgroup(page
);
3539 lock_page_cgroup(pc
);
3540 pc
->mem_cgroup
= memcg
;
3541 SetPageCgroupUsed(pc
);
3542 unlock_page_cgroup(pc
);
3545 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3547 struct mem_cgroup
*memcg
= NULL
;
3548 struct page_cgroup
*pc
;
3551 pc
= lookup_page_cgroup(page
);
3553 * Fast unlocked return. Theoretically might have changed, have to
3554 * check again after locking.
3556 if (!PageCgroupUsed(pc
))
3559 lock_page_cgroup(pc
);
3560 if (PageCgroupUsed(pc
)) {
3561 memcg
= pc
->mem_cgroup
;
3562 ClearPageCgroupUsed(pc
);
3564 unlock_page_cgroup(pc
);
3567 * We trust that only if there is a memcg associated with the page, it
3568 * is a valid allocation
3573 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3574 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3577 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3580 #endif /* CONFIG_MEMCG_KMEM */
3582 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3584 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3586 * Because tail pages are not marked as "used", set it. We're under
3587 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3588 * charge/uncharge will be never happen and move_account() is done under
3589 * compound_lock(), so we don't have to take care of races.
3591 void mem_cgroup_split_huge_fixup(struct page
*head
)
3593 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3594 struct page_cgroup
*pc
;
3597 if (mem_cgroup_disabled())
3599 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3601 pc
->mem_cgroup
= head_pc
->mem_cgroup
;
3602 smp_wmb();/* see __commit_charge() */
3603 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3606 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3609 * mem_cgroup_move_account - move account of the page
3611 * @nr_pages: number of regular pages (>1 for huge pages)
3612 * @pc: page_cgroup of the page.
3613 * @from: mem_cgroup which the page is moved from.
3614 * @to: mem_cgroup which the page is moved to. @from != @to.
3616 * The caller must confirm following.
3617 * - page is not on LRU (isolate_page() is useful.)
3618 * - compound_lock is held when nr_pages > 1
3620 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3623 static int mem_cgroup_move_account(struct page
*page
,
3624 unsigned int nr_pages
,
3625 struct page_cgroup
*pc
,
3626 struct mem_cgroup
*from
,
3627 struct mem_cgroup
*to
)
3629 unsigned long flags
;
3631 bool anon
= PageAnon(page
);
3633 VM_BUG_ON(from
== to
);
3634 VM_BUG_ON(PageLRU(page
));
3636 * The page is isolated from LRU. So, collapse function
3637 * will not handle this page. But page splitting can happen.
3638 * Do this check under compound_page_lock(). The caller should
3642 if (nr_pages
> 1 && !PageTransHuge(page
))
3645 lock_page_cgroup(pc
);
3648 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3651 move_lock_mem_cgroup(from
, &flags
);
3653 if (!anon
&& page_mapped(page
)) {
3654 /* Update mapped_file data for mem_cgroup */
3656 __this_cpu_dec(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3657 __this_cpu_inc(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3660 mem_cgroup_charge_statistics(from
, anon
, -nr_pages
);
3662 /* caller should have done css_get */
3663 pc
->mem_cgroup
= to
;
3664 mem_cgroup_charge_statistics(to
, anon
, nr_pages
);
3665 move_unlock_mem_cgroup(from
, &flags
);
3668 unlock_page_cgroup(pc
);
3672 memcg_check_events(to
, page
);
3673 memcg_check_events(from
, page
);
3679 * mem_cgroup_move_parent - moves page to the parent group
3680 * @page: the page to move
3681 * @pc: page_cgroup of the page
3682 * @child: page's cgroup
3684 * move charges to its parent or the root cgroup if the group has no
3685 * parent (aka use_hierarchy==0).
3686 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3687 * mem_cgroup_move_account fails) the failure is always temporary and
3688 * it signals a race with a page removal/uncharge or migration. In the
3689 * first case the page is on the way out and it will vanish from the LRU
3690 * on the next attempt and the call should be retried later.
3691 * Isolation from the LRU fails only if page has been isolated from
3692 * the LRU since we looked at it and that usually means either global
3693 * reclaim or migration going on. The page will either get back to the
3695 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3696 * (!PageCgroupUsed) or moved to a different group. The page will
3697 * disappear in the next attempt.
3699 static int mem_cgroup_move_parent(struct page
*page
,
3700 struct page_cgroup
*pc
,
3701 struct mem_cgroup
*child
)
3703 struct mem_cgroup
*parent
;
3704 unsigned int nr_pages
;
3705 unsigned long uninitialized_var(flags
);
3708 VM_BUG_ON(mem_cgroup_is_root(child
));
3711 if (!get_page_unless_zero(page
))
3713 if (isolate_lru_page(page
))
3716 nr_pages
= hpage_nr_pages(page
);
3718 parent
= parent_mem_cgroup(child
);
3720 * If no parent, move charges to root cgroup.
3723 parent
= root_mem_cgroup
;
3726 VM_BUG_ON(!PageTransHuge(page
));
3727 flags
= compound_lock_irqsave(page
);
3730 ret
= mem_cgroup_move_account(page
, nr_pages
,
3733 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3736 compound_unlock_irqrestore(page
, flags
);
3737 putback_lru_page(page
);
3745 * Charge the memory controller for page usage.
3747 * 0 if the charge was successful
3748 * < 0 if the cgroup is over its limit
3750 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
3751 gfp_t gfp_mask
, enum charge_type ctype
)
3753 struct mem_cgroup
*memcg
= NULL
;
3754 unsigned int nr_pages
= 1;
3758 if (PageTransHuge(page
)) {
3759 nr_pages
<<= compound_order(page
);
3760 VM_BUG_ON(!PageTransHuge(page
));
3762 * Never OOM-kill a process for a huge page. The
3763 * fault handler will fall back to regular pages.
3768 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
3771 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
3775 int mem_cgroup_newpage_charge(struct page
*page
,
3776 struct mm_struct
*mm
, gfp_t gfp_mask
)
3778 if (mem_cgroup_disabled())
3780 VM_BUG_ON(page_mapped(page
));
3781 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
3783 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
3784 MEM_CGROUP_CHARGE_TYPE_ANON
);
3788 * While swap-in, try_charge -> commit or cancel, the page is locked.
3789 * And when try_charge() successfully returns, one refcnt to memcg without
3790 * struct page_cgroup is acquired. This refcnt will be consumed by
3791 * "commit()" or removed by "cancel()"
3793 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
3796 struct mem_cgroup
**memcgp
)
3798 struct mem_cgroup
*memcg
;
3799 struct page_cgroup
*pc
;
3802 pc
= lookup_page_cgroup(page
);
3804 * Every swap fault against a single page tries to charge the
3805 * page, bail as early as possible. shmem_unuse() encounters
3806 * already charged pages, too. The USED bit is protected by
3807 * the page lock, which serializes swap cache removal, which
3808 * in turn serializes uncharging.
3810 if (PageCgroupUsed(pc
))
3812 if (!do_swap_account
)
3814 memcg
= try_get_mem_cgroup_from_page(page
);
3818 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
3819 css_put(&memcg
->css
);
3824 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
3830 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
3831 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
3834 if (mem_cgroup_disabled())
3837 * A racing thread's fault, or swapoff, may have already
3838 * updated the pte, and even removed page from swap cache: in
3839 * those cases unuse_pte()'s pte_same() test will fail; but
3840 * there's also a KSM case which does need to charge the page.
3842 if (!PageSwapCache(page
)) {
3845 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
3850 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
3853 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
3855 if (mem_cgroup_disabled())
3859 __mem_cgroup_cancel_charge(memcg
, 1);
3863 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
3864 enum charge_type ctype
)
3866 if (mem_cgroup_disabled())
3871 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
3873 * Now swap is on-memory. This means this page may be
3874 * counted both as mem and swap....double count.
3875 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3876 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3877 * may call delete_from_swap_cache() before reach here.
3879 if (do_swap_account
&& PageSwapCache(page
)) {
3880 swp_entry_t ent
= {.val
= page_private(page
)};
3881 mem_cgroup_uncharge_swap(ent
);
3885 void mem_cgroup_commit_charge_swapin(struct page
*page
,
3886 struct mem_cgroup
*memcg
)
3888 __mem_cgroup_commit_charge_swapin(page
, memcg
,
3889 MEM_CGROUP_CHARGE_TYPE_ANON
);
3892 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
3895 struct mem_cgroup
*memcg
= NULL
;
3896 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
3899 if (mem_cgroup_disabled())
3901 if (PageCompound(page
))
3904 if (!PageSwapCache(page
))
3905 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
3906 else { /* page is swapcache/shmem */
3907 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
3910 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
3915 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
3916 unsigned int nr_pages
,
3917 const enum charge_type ctype
)
3919 struct memcg_batch_info
*batch
= NULL
;
3920 bool uncharge_memsw
= true;
3922 /* If swapout, usage of swap doesn't decrease */
3923 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
3924 uncharge_memsw
= false;
3926 batch
= ¤t
->memcg_batch
;
3928 * In usual, we do css_get() when we remember memcg pointer.
3929 * But in this case, we keep res->usage until end of a series of
3930 * uncharges. Then, it's ok to ignore memcg's refcnt.
3933 batch
->memcg
= memcg
;
3935 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
3936 * In those cases, all pages freed continuously can be expected to be in
3937 * the same cgroup and we have chance to coalesce uncharges.
3938 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
3939 * because we want to do uncharge as soon as possible.
3942 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
3943 goto direct_uncharge
;
3946 goto direct_uncharge
;
3949 * In typical case, batch->memcg == mem. This means we can
3950 * merge a series of uncharges to an uncharge of res_counter.
3951 * If not, we uncharge res_counter ony by one.
3953 if (batch
->memcg
!= memcg
)
3954 goto direct_uncharge
;
3955 /* remember freed charge and uncharge it later */
3958 batch
->memsw_nr_pages
++;
3961 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
3963 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
3964 if (unlikely(batch
->memcg
!= memcg
))
3965 memcg_oom_recover(memcg
);
3969 * uncharge if !page_mapped(page)
3971 static struct mem_cgroup
*
3972 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
3975 struct mem_cgroup
*memcg
= NULL
;
3976 unsigned int nr_pages
= 1;
3977 struct page_cgroup
*pc
;
3980 if (mem_cgroup_disabled())
3983 VM_BUG_ON(PageSwapCache(page
));
3985 if (PageTransHuge(page
)) {
3986 nr_pages
<<= compound_order(page
);
3987 VM_BUG_ON(!PageTransHuge(page
));
3990 * Check if our page_cgroup is valid
3992 pc
= lookup_page_cgroup(page
);
3993 if (unlikely(!PageCgroupUsed(pc
)))
3996 lock_page_cgroup(pc
);
3998 memcg
= pc
->mem_cgroup
;
4000 if (!PageCgroupUsed(pc
))
4003 anon
= PageAnon(page
);
4006 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4008 * Generally PageAnon tells if it's the anon statistics to be
4009 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4010 * used before page reached the stage of being marked PageAnon.
4014 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4015 /* See mem_cgroup_prepare_migration() */
4016 if (page_mapped(page
))
4019 * Pages under migration may not be uncharged. But
4020 * end_migration() /must/ be the one uncharging the
4021 * unused post-migration page and so it has to call
4022 * here with the migration bit still set. See the
4023 * res_counter handling below.
4025 if (!end_migration
&& PageCgroupMigration(pc
))
4028 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4029 if (!PageAnon(page
)) { /* Shared memory */
4030 if (page
->mapping
&& !page_is_file_cache(page
))
4032 } else if (page_mapped(page
)) /* Anon */
4039 mem_cgroup_charge_statistics(memcg
, anon
, -nr_pages
);
4041 ClearPageCgroupUsed(pc
);
4043 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4044 * freed from LRU. This is safe because uncharged page is expected not
4045 * to be reused (freed soon). Exception is SwapCache, it's handled by
4046 * special functions.
4049 unlock_page_cgroup(pc
);
4051 * even after unlock, we have memcg->res.usage here and this memcg
4052 * will never be freed.
4054 memcg_check_events(memcg
, page
);
4055 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4056 mem_cgroup_swap_statistics(memcg
, true);
4057 mem_cgroup_get(memcg
);
4060 * Migration does not charge the res_counter for the
4061 * replacement page, so leave it alone when phasing out the
4062 * page that is unused after the migration.
4064 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4065 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4070 unlock_page_cgroup(pc
);
4074 void mem_cgroup_uncharge_page(struct page
*page
)
4077 if (page_mapped(page
))
4079 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
4080 if (PageSwapCache(page
))
4082 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4085 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4087 VM_BUG_ON(page_mapped(page
));
4088 VM_BUG_ON(page
->mapping
);
4089 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4093 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4094 * In that cases, pages are freed continuously and we can expect pages
4095 * are in the same memcg. All these calls itself limits the number of
4096 * pages freed at once, then uncharge_start/end() is called properly.
4097 * This may be called prural(2) times in a context,
4100 void mem_cgroup_uncharge_start(void)
4102 current
->memcg_batch
.do_batch
++;
4103 /* We can do nest. */
4104 if (current
->memcg_batch
.do_batch
== 1) {
4105 current
->memcg_batch
.memcg
= NULL
;
4106 current
->memcg_batch
.nr_pages
= 0;
4107 current
->memcg_batch
.memsw_nr_pages
= 0;
4111 void mem_cgroup_uncharge_end(void)
4113 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4115 if (!batch
->do_batch
)
4119 if (batch
->do_batch
) /* If stacked, do nothing. */
4125 * This "batch->memcg" is valid without any css_get/put etc...
4126 * bacause we hide charges behind us.
4128 if (batch
->nr_pages
)
4129 res_counter_uncharge(&batch
->memcg
->res
,
4130 batch
->nr_pages
* PAGE_SIZE
);
4131 if (batch
->memsw_nr_pages
)
4132 res_counter_uncharge(&batch
->memcg
->memsw
,
4133 batch
->memsw_nr_pages
* PAGE_SIZE
);
4134 memcg_oom_recover(batch
->memcg
);
4135 /* forget this pointer (for sanity check) */
4136 batch
->memcg
= NULL
;
4141 * called after __delete_from_swap_cache() and drop "page" account.
4142 * memcg information is recorded to swap_cgroup of "ent"
4145 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4147 struct mem_cgroup
*memcg
;
4148 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4150 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4151 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4153 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4156 * record memcg information, if swapout && memcg != NULL,
4157 * mem_cgroup_get() was called in uncharge().
4159 if (do_swap_account
&& swapout
&& memcg
)
4160 swap_cgroup_record(ent
, css_id(&memcg
->css
));
4164 #ifdef CONFIG_MEMCG_SWAP
4166 * called from swap_entry_free(). remove record in swap_cgroup and
4167 * uncharge "memsw" account.
4169 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4171 struct mem_cgroup
*memcg
;
4174 if (!do_swap_account
)
4177 id
= swap_cgroup_record(ent
, 0);
4179 memcg
= mem_cgroup_lookup(id
);
4182 * We uncharge this because swap is freed.
4183 * This memcg can be obsolete one. We avoid calling css_tryget
4185 if (!mem_cgroup_is_root(memcg
))
4186 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4187 mem_cgroup_swap_statistics(memcg
, false);
4188 mem_cgroup_put(memcg
);
4194 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4195 * @entry: swap entry to be moved
4196 * @from: mem_cgroup which the entry is moved from
4197 * @to: mem_cgroup which the entry is moved to
4199 * It succeeds only when the swap_cgroup's record for this entry is the same
4200 * as the mem_cgroup's id of @from.
4202 * Returns 0 on success, -EINVAL on failure.
4204 * The caller must have charged to @to, IOW, called res_counter_charge() about
4205 * both res and memsw, and called css_get().
4207 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4208 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4210 unsigned short old_id
, new_id
;
4212 old_id
= css_id(&from
->css
);
4213 new_id
= css_id(&to
->css
);
4215 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4216 mem_cgroup_swap_statistics(from
, false);
4217 mem_cgroup_swap_statistics(to
, true);
4219 * This function is only called from task migration context now.
4220 * It postpones res_counter and refcount handling till the end
4221 * of task migration(mem_cgroup_clear_mc()) for performance
4222 * improvement. But we cannot postpone mem_cgroup_get(to)
4223 * because if the process that has been moved to @to does
4224 * swap-in, the refcount of @to might be decreased to 0.
4232 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4233 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4240 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4243 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4244 struct mem_cgroup
**memcgp
)
4246 struct mem_cgroup
*memcg
= NULL
;
4247 unsigned int nr_pages
= 1;
4248 struct page_cgroup
*pc
;
4249 enum charge_type ctype
;
4253 if (mem_cgroup_disabled())
4256 if (PageTransHuge(page
))
4257 nr_pages
<<= compound_order(page
);
4259 pc
= lookup_page_cgroup(page
);
4260 lock_page_cgroup(pc
);
4261 if (PageCgroupUsed(pc
)) {
4262 memcg
= pc
->mem_cgroup
;
4263 css_get(&memcg
->css
);
4265 * At migrating an anonymous page, its mapcount goes down
4266 * to 0 and uncharge() will be called. But, even if it's fully
4267 * unmapped, migration may fail and this page has to be
4268 * charged again. We set MIGRATION flag here and delay uncharge
4269 * until end_migration() is called
4271 * Corner Case Thinking
4273 * When the old page was mapped as Anon and it's unmap-and-freed
4274 * while migration was ongoing.
4275 * If unmap finds the old page, uncharge() of it will be delayed
4276 * until end_migration(). If unmap finds a new page, it's
4277 * uncharged when it make mapcount to be 1->0. If unmap code
4278 * finds swap_migration_entry, the new page will not be mapped
4279 * and end_migration() will find it(mapcount==0).
4282 * When the old page was mapped but migraion fails, the kernel
4283 * remaps it. A charge for it is kept by MIGRATION flag even
4284 * if mapcount goes down to 0. We can do remap successfully
4285 * without charging it again.
4288 * The "old" page is under lock_page() until the end of
4289 * migration, so, the old page itself will not be swapped-out.
4290 * If the new page is swapped out before end_migraton, our
4291 * hook to usual swap-out path will catch the event.
4294 SetPageCgroupMigration(pc
);
4296 unlock_page_cgroup(pc
);
4298 * If the page is not charged at this point,
4306 * We charge new page before it's used/mapped. So, even if unlock_page()
4307 * is called before end_migration, we can catch all events on this new
4308 * page. In the case new page is migrated but not remapped, new page's
4309 * mapcount will be finally 0 and we call uncharge in end_migration().
4312 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4314 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4316 * The page is committed to the memcg, but it's not actually
4317 * charged to the res_counter since we plan on replacing the
4318 * old one and only one page is going to be left afterwards.
4320 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4323 /* remove redundant charge if migration failed*/
4324 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4325 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4327 struct page
*used
, *unused
;
4328 struct page_cgroup
*pc
;
4334 if (!migration_ok
) {
4341 anon
= PageAnon(used
);
4342 __mem_cgroup_uncharge_common(unused
,
4343 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4344 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4346 css_put(&memcg
->css
);
4348 * We disallowed uncharge of pages under migration because mapcount
4349 * of the page goes down to zero, temporarly.
4350 * Clear the flag and check the page should be charged.
4352 pc
= lookup_page_cgroup(oldpage
);
4353 lock_page_cgroup(pc
);
4354 ClearPageCgroupMigration(pc
);
4355 unlock_page_cgroup(pc
);
4358 * If a page is a file cache, radix-tree replacement is very atomic
4359 * and we can skip this check. When it was an Anon page, its mapcount
4360 * goes down to 0. But because we added MIGRATION flage, it's not
4361 * uncharged yet. There are several case but page->mapcount check
4362 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4363 * check. (see prepare_charge() also)
4366 mem_cgroup_uncharge_page(used
);
4370 * At replace page cache, newpage is not under any memcg but it's on
4371 * LRU. So, this function doesn't touch res_counter but handles LRU
4372 * in correct way. Both pages are locked so we cannot race with uncharge.
4374 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4375 struct page
*newpage
)
4377 struct mem_cgroup
*memcg
= NULL
;
4378 struct page_cgroup
*pc
;
4379 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4381 if (mem_cgroup_disabled())
4384 pc
= lookup_page_cgroup(oldpage
);
4385 /* fix accounting on old pages */
4386 lock_page_cgroup(pc
);
4387 if (PageCgroupUsed(pc
)) {
4388 memcg
= pc
->mem_cgroup
;
4389 mem_cgroup_charge_statistics(memcg
, false, -1);
4390 ClearPageCgroupUsed(pc
);
4392 unlock_page_cgroup(pc
);
4395 * When called from shmem_replace_page(), in some cases the
4396 * oldpage has already been charged, and in some cases not.
4401 * Even if newpage->mapping was NULL before starting replacement,
4402 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4403 * LRU while we overwrite pc->mem_cgroup.
4405 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4408 #ifdef CONFIG_DEBUG_VM
4409 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4411 struct page_cgroup
*pc
;
4413 pc
= lookup_page_cgroup(page
);
4415 * Can be NULL while feeding pages into the page allocator for
4416 * the first time, i.e. during boot or memory hotplug;
4417 * or when mem_cgroup_disabled().
4419 if (likely(pc
) && PageCgroupUsed(pc
))
4424 bool mem_cgroup_bad_page_check(struct page
*page
)
4426 if (mem_cgroup_disabled())
4429 return lookup_page_cgroup_used(page
) != NULL
;
4432 void mem_cgroup_print_bad_page(struct page
*page
)
4434 struct page_cgroup
*pc
;
4436 pc
= lookup_page_cgroup_used(page
);
4438 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4439 pc
, pc
->flags
, pc
->mem_cgroup
);
4444 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4445 unsigned long long val
)
4448 u64 memswlimit
, memlimit
;
4450 int children
= mem_cgroup_count_children(memcg
);
4451 u64 curusage
, oldusage
;
4455 * For keeping hierarchical_reclaim simple, how long we should retry
4456 * is depends on callers. We set our retry-count to be function
4457 * of # of children which we should visit in this loop.
4459 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4461 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4464 while (retry_count
) {
4465 if (signal_pending(current
)) {
4470 * Rather than hide all in some function, I do this in
4471 * open coded manner. You see what this really does.
4472 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4474 mutex_lock(&set_limit_mutex
);
4475 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4476 if (memswlimit
< val
) {
4478 mutex_unlock(&set_limit_mutex
);
4482 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4486 ret
= res_counter_set_limit(&memcg
->res
, val
);
4488 if (memswlimit
== val
)
4489 memcg
->memsw_is_minimum
= true;
4491 memcg
->memsw_is_minimum
= false;
4493 mutex_unlock(&set_limit_mutex
);
4498 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4499 MEM_CGROUP_RECLAIM_SHRINK
);
4500 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4501 /* Usage is reduced ? */
4502 if (curusage
>= oldusage
)
4505 oldusage
= curusage
;
4507 if (!ret
&& enlarge
)
4508 memcg_oom_recover(memcg
);
4513 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4514 unsigned long long val
)
4517 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4518 int children
= mem_cgroup_count_children(memcg
);
4522 /* see mem_cgroup_resize_res_limit */
4523 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4524 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4525 while (retry_count
) {
4526 if (signal_pending(current
)) {
4531 * Rather than hide all in some function, I do this in
4532 * open coded manner. You see what this really does.
4533 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4535 mutex_lock(&set_limit_mutex
);
4536 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4537 if (memlimit
> val
) {
4539 mutex_unlock(&set_limit_mutex
);
4542 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4543 if (memswlimit
< val
)
4545 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4547 if (memlimit
== val
)
4548 memcg
->memsw_is_minimum
= true;
4550 memcg
->memsw_is_minimum
= false;
4552 mutex_unlock(&set_limit_mutex
);
4557 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4558 MEM_CGROUP_RECLAIM_NOSWAP
|
4559 MEM_CGROUP_RECLAIM_SHRINK
);
4560 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4561 /* Usage is reduced ? */
4562 if (curusage
>= oldusage
)
4565 oldusage
= curusage
;
4567 if (!ret
&& enlarge
)
4568 memcg_oom_recover(memcg
);
4572 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
4574 unsigned long *total_scanned
)
4576 unsigned long nr_reclaimed
= 0;
4577 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
4578 unsigned long reclaimed
;
4580 struct mem_cgroup_tree_per_zone
*mctz
;
4581 unsigned long long excess
;
4582 unsigned long nr_scanned
;
4587 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
4589 * This loop can run a while, specially if mem_cgroup's continuously
4590 * keep exceeding their soft limit and putting the system under
4597 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
4602 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
4603 gfp_mask
, &nr_scanned
);
4604 nr_reclaimed
+= reclaimed
;
4605 *total_scanned
+= nr_scanned
;
4606 spin_lock(&mctz
->lock
);
4609 * If we failed to reclaim anything from this memory cgroup
4610 * it is time to move on to the next cgroup
4616 * Loop until we find yet another one.
4618 * By the time we get the soft_limit lock
4619 * again, someone might have aded the
4620 * group back on the RB tree. Iterate to
4621 * make sure we get a different mem.
4622 * mem_cgroup_largest_soft_limit_node returns
4623 * NULL if no other cgroup is present on
4627 __mem_cgroup_largest_soft_limit_node(mctz
);
4629 css_put(&next_mz
->memcg
->css
);
4630 else /* next_mz == NULL or other memcg */
4634 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
4635 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
4637 * One school of thought says that we should not add
4638 * back the node to the tree if reclaim returns 0.
4639 * But our reclaim could return 0, simply because due
4640 * to priority we are exposing a smaller subset of
4641 * memory to reclaim from. Consider this as a longer
4644 /* If excess == 0, no tree ops */
4645 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
4646 spin_unlock(&mctz
->lock
);
4647 css_put(&mz
->memcg
->css
);
4650 * Could not reclaim anything and there are no more
4651 * mem cgroups to try or we seem to be looping without
4652 * reclaiming anything.
4654 if (!nr_reclaimed
&&
4656 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
4658 } while (!nr_reclaimed
);
4660 css_put(&next_mz
->memcg
->css
);
4661 return nr_reclaimed
;
4665 * mem_cgroup_force_empty_list - clears LRU of a group
4666 * @memcg: group to clear
4669 * @lru: lru to to clear
4671 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4672 * reclaim the pages page themselves - pages are moved to the parent (or root)
4675 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4676 int node
, int zid
, enum lru_list lru
)
4678 struct lruvec
*lruvec
;
4679 unsigned long flags
;
4680 struct list_head
*list
;
4684 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4685 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4686 list
= &lruvec
->lists
[lru
];
4690 struct page_cgroup
*pc
;
4693 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4694 if (list_empty(list
)) {
4695 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4698 page
= list_entry(list
->prev
, struct page
, lru
);
4700 list_move(&page
->lru
, list
);
4702 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4705 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4707 pc
= lookup_page_cgroup(page
);
4709 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4710 /* found lock contention or "pc" is obsolete. */
4715 } while (!list_empty(list
));
4719 * make mem_cgroup's charge to be 0 if there is no task by moving
4720 * all the charges and pages to the parent.
4721 * This enables deleting this mem_cgroup.
4723 * Caller is responsible for holding css reference on the memcg.
4725 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4731 /* This is for making all *used* pages to be on LRU. */
4732 lru_add_drain_all();
4733 drain_all_stock_sync(memcg
);
4734 mem_cgroup_start_move(memcg
);
4735 for_each_node_state(node
, N_MEMORY
) {
4736 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4739 mem_cgroup_force_empty_list(memcg
,
4744 mem_cgroup_end_move(memcg
);
4745 memcg_oom_recover(memcg
);
4749 * Kernel memory may not necessarily be trackable to a specific
4750 * process. So they are not migrated, and therefore we can't
4751 * expect their value to drop to 0 here.
4752 * Having res filled up with kmem only is enough.
4754 * This is a safety check because mem_cgroup_force_empty_list
4755 * could have raced with mem_cgroup_replace_page_cache callers
4756 * so the lru seemed empty but the page could have been added
4757 * right after the check. RES_USAGE should be safe as we always
4758 * charge before adding to the LRU.
4760 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
4761 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
4762 } while (usage
> 0);
4766 * Reclaims as many pages from the given memcg as possible and moves
4767 * the rest to the parent.
4769 * Caller is responsible for holding css reference for memcg.
4771 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
4773 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
4774 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
4776 /* returns EBUSY if there is a task or if we come here twice. */
4777 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
4780 /* we call try-to-free pages for make this cgroup empty */
4781 lru_add_drain_all();
4782 /* try to free all pages in this cgroup */
4783 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
4786 if (signal_pending(current
))
4789 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
4793 /* maybe some writeback is necessary */
4794 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
4799 mem_cgroup_reparent_charges(memcg
);
4804 static int mem_cgroup_force_empty_write(struct cgroup
*cont
, unsigned int event
)
4806 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4809 if (mem_cgroup_is_root(memcg
))
4811 css_get(&memcg
->css
);
4812 ret
= mem_cgroup_force_empty(memcg
);
4813 css_put(&memcg
->css
);
4819 static u64
mem_cgroup_hierarchy_read(struct cgroup
*cont
, struct cftype
*cft
)
4821 return mem_cgroup_from_cont(cont
)->use_hierarchy
;
4824 static int mem_cgroup_hierarchy_write(struct cgroup
*cont
, struct cftype
*cft
,
4828 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4829 struct cgroup
*parent
= cont
->parent
;
4830 struct mem_cgroup
*parent_memcg
= NULL
;
4833 parent_memcg
= mem_cgroup_from_cont(parent
);
4837 if (memcg
->use_hierarchy
== val
)
4841 * If parent's use_hierarchy is set, we can't make any modifications
4842 * in the child subtrees. If it is unset, then the change can
4843 * occur, provided the current cgroup has no children.
4845 * For the root cgroup, parent_mem is NULL, we allow value to be
4846 * set if there are no children.
4848 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
4849 (val
== 1 || val
== 0)) {
4850 if (list_empty(&cont
->children
))
4851 memcg
->use_hierarchy
= val
;
4864 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
4865 enum mem_cgroup_stat_index idx
)
4867 struct mem_cgroup
*iter
;
4870 /* Per-cpu values can be negative, use a signed accumulator */
4871 for_each_mem_cgroup_tree(iter
, memcg
)
4872 val
+= mem_cgroup_read_stat(iter
, idx
);
4874 if (val
< 0) /* race ? */
4879 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
4883 if (!mem_cgroup_is_root(memcg
)) {
4885 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4887 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4890 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
4891 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
4894 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
4896 return val
<< PAGE_SHIFT
;
4899 static ssize_t
mem_cgroup_read(struct cgroup
*cont
, struct cftype
*cft
,
4900 struct file
*file
, char __user
*buf
,
4901 size_t nbytes
, loff_t
*ppos
)
4903 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4909 type
= MEMFILE_TYPE(cft
->private);
4910 name
= MEMFILE_ATTR(cft
->private);
4912 if (!do_swap_account
&& type
== _MEMSWAP
)
4917 if (name
== RES_USAGE
)
4918 val
= mem_cgroup_usage(memcg
, false);
4920 val
= res_counter_read_u64(&memcg
->res
, name
);
4923 if (name
== RES_USAGE
)
4924 val
= mem_cgroup_usage(memcg
, true);
4926 val
= res_counter_read_u64(&memcg
->memsw
, name
);
4929 val
= res_counter_read_u64(&memcg
->kmem
, name
);
4935 len
= scnprintf(str
, sizeof(str
), "%llu\n", (unsigned long long)val
);
4936 return simple_read_from_buffer(buf
, nbytes
, ppos
, str
, len
);
4939 static int memcg_update_kmem_limit(struct cgroup
*cont
, u64 val
)
4942 #ifdef CONFIG_MEMCG_KMEM
4943 bool must_inc_static_branch
= false;
4945 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4947 * For simplicity, we won't allow this to be disabled. It also can't
4948 * be changed if the cgroup has children already, or if tasks had
4951 * If tasks join before we set the limit, a person looking at
4952 * kmem.usage_in_bytes will have no way to determine when it took
4953 * place, which makes the value quite meaningless.
4955 * After it first became limited, changes in the value of the limit are
4956 * of course permitted.
4958 * Taking the cgroup_lock is really offensive, but it is so far the only
4959 * way to guarantee that no children will appear. There are plenty of
4960 * other offenders, and they should all go away. Fine grained locking
4961 * is probably the way to go here. When we are fully hierarchical, we
4962 * can also get rid of the use_hierarchy check.
4965 mutex_lock(&set_limit_mutex
);
4966 if (!memcg
->kmem_account_flags
&& val
!= RESOURCE_MAX
) {
4967 if (cgroup_task_count(cont
) || (memcg
->use_hierarchy
&&
4968 !list_empty(&cont
->children
))) {
4972 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
4975 ret
= memcg_update_cache_sizes(memcg
);
4977 res_counter_set_limit(&memcg
->kmem
, RESOURCE_MAX
);
4980 must_inc_static_branch
= true;
4982 * kmem charges can outlive the cgroup. In the case of slab
4983 * pages, for instance, a page contain objects from various
4984 * processes, so it is unfeasible to migrate them away. We
4985 * need to reference count the memcg because of that.
4987 mem_cgroup_get(memcg
);
4989 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
4991 mutex_unlock(&set_limit_mutex
);
4995 * We are by now familiar with the fact that we can't inc the static
4996 * branch inside cgroup_lock. See disarm functions for details. A
4997 * worker here is overkill, but also wrong: After the limit is set, we
4998 * must start accounting right away. Since this operation can't fail,
4999 * we can safely defer it to here - no rollback will be needed.
5001 * The boolean used to control this is also safe, because
5002 * KMEM_ACCOUNTED_ACTIVATED guarantees that only one process will be
5003 * able to set it to true;
5005 if (must_inc_static_branch
) {
5006 static_key_slow_inc(&memcg_kmem_enabled_key
);
5008 * setting the active bit after the inc will guarantee no one
5009 * starts accounting before all call sites are patched
5011 memcg_kmem_set_active(memcg
);
5018 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5021 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5025 memcg
->kmem_account_flags
= parent
->kmem_account_flags
;
5026 #ifdef CONFIG_MEMCG_KMEM
5028 * When that happen, we need to disable the static branch only on those
5029 * memcgs that enabled it. To achieve this, we would be forced to
5030 * complicate the code by keeping track of which memcgs were the ones
5031 * that actually enabled limits, and which ones got it from its
5034 * It is a lot simpler just to do static_key_slow_inc() on every child
5035 * that is accounted.
5037 if (!memcg_kmem_is_active(memcg
))
5041 * destroy(), called if we fail, will issue static_key_slow_inc() and
5042 * mem_cgroup_put() if kmem is enabled. We have to either call them
5043 * unconditionally, or clear the KMEM_ACTIVE flag. I personally find
5044 * this more consistent, since it always leads to the same destroy path
5046 mem_cgroup_get(memcg
);
5047 static_key_slow_inc(&memcg_kmem_enabled_key
);
5049 mutex_lock(&set_limit_mutex
);
5050 ret
= memcg_update_cache_sizes(memcg
);
5051 mutex_unlock(&set_limit_mutex
);
5058 * The user of this function is...
5061 static int mem_cgroup_write(struct cgroup
*cont
, struct cftype
*cft
,
5064 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5067 unsigned long long val
;
5070 type
= MEMFILE_TYPE(cft
->private);
5071 name
= MEMFILE_ATTR(cft
->private);
5073 if (!do_swap_account
&& type
== _MEMSWAP
)
5078 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5082 /* This function does all necessary parse...reuse it */
5083 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5087 ret
= mem_cgroup_resize_limit(memcg
, val
);
5088 else if (type
== _MEMSWAP
)
5089 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5090 else if (type
== _KMEM
)
5091 ret
= memcg_update_kmem_limit(cont
, val
);
5095 case RES_SOFT_LIMIT
:
5096 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5100 * For memsw, soft limits are hard to implement in terms
5101 * of semantics, for now, we support soft limits for
5102 * control without swap
5105 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5110 ret
= -EINVAL
; /* should be BUG() ? */
5116 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5117 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5119 struct cgroup
*cgroup
;
5120 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5122 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5123 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5124 cgroup
= memcg
->css
.cgroup
;
5125 if (!memcg
->use_hierarchy
)
5128 while (cgroup
->parent
) {
5129 cgroup
= cgroup
->parent
;
5130 memcg
= mem_cgroup_from_cont(cgroup
);
5131 if (!memcg
->use_hierarchy
)
5133 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5134 min_limit
= min(min_limit
, tmp
);
5135 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5136 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5139 *mem_limit
= min_limit
;
5140 *memsw_limit
= min_memsw_limit
;
5143 static int mem_cgroup_reset(struct cgroup
*cont
, unsigned int event
)
5145 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5149 type
= MEMFILE_TYPE(event
);
5150 name
= MEMFILE_ATTR(event
);
5152 if (!do_swap_account
&& type
== _MEMSWAP
)
5158 res_counter_reset_max(&memcg
->res
);
5159 else if (type
== _MEMSWAP
)
5160 res_counter_reset_max(&memcg
->memsw
);
5161 else if (type
== _KMEM
)
5162 res_counter_reset_max(&memcg
->kmem
);
5168 res_counter_reset_failcnt(&memcg
->res
);
5169 else if (type
== _MEMSWAP
)
5170 res_counter_reset_failcnt(&memcg
->memsw
);
5171 else if (type
== _KMEM
)
5172 res_counter_reset_failcnt(&memcg
->kmem
);
5181 static u64
mem_cgroup_move_charge_read(struct cgroup
*cgrp
,
5184 return mem_cgroup_from_cont(cgrp
)->move_charge_at_immigrate
;
5188 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
5189 struct cftype
*cft
, u64 val
)
5191 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5193 if (val
>= (1 << NR_MOVE_TYPE
))
5197 * No kind of locking is needed in here, because ->can_attach() will
5198 * check this value once in the beginning of the process, and then carry
5199 * on with stale data. This means that changes to this value will only
5200 * affect task migrations starting after the change.
5202 memcg
->move_charge_at_immigrate
= val
;
5206 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
5207 struct cftype
*cft
, u64 val
)
5214 static int memcg_numa_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
5218 unsigned long total_nr
, file_nr
, anon_nr
, unevictable_nr
;
5219 unsigned long node_nr
;
5220 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5222 total_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL
);
5223 seq_printf(m
, "total=%lu", total_nr
);
5224 for_each_node_state(nid
, N_MEMORY
) {
5225 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL
);
5226 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5230 file_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_FILE
);
5231 seq_printf(m
, "file=%lu", file_nr
);
5232 for_each_node_state(nid
, N_MEMORY
) {
5233 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5235 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5239 anon_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_ANON
);
5240 seq_printf(m
, "anon=%lu", anon_nr
);
5241 for_each_node_state(nid
, N_MEMORY
) {
5242 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5244 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5248 unevictable_nr
= mem_cgroup_nr_lru_pages(memcg
, BIT(LRU_UNEVICTABLE
));
5249 seq_printf(m
, "unevictable=%lu", unevictable_nr
);
5250 for_each_node_state(nid
, N_MEMORY
) {
5251 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5252 BIT(LRU_UNEVICTABLE
));
5253 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5258 #endif /* CONFIG_NUMA */
5260 static inline void mem_cgroup_lru_names_not_uptodate(void)
5262 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5265 static int memcg_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
5268 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5269 struct mem_cgroup
*mi
;
5272 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5273 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5275 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5276 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5279 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5280 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5281 mem_cgroup_read_events(memcg
, i
));
5283 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5284 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5285 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5287 /* Hierarchical information */
5289 unsigned long long limit
, memsw_limit
;
5290 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5291 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5292 if (do_swap_account
)
5293 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5297 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5300 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5302 for_each_mem_cgroup_tree(mi
, memcg
)
5303 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5304 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5307 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5308 unsigned long long val
= 0;
5310 for_each_mem_cgroup_tree(mi
, memcg
)
5311 val
+= mem_cgroup_read_events(mi
, i
);
5312 seq_printf(m
, "total_%s %llu\n",
5313 mem_cgroup_events_names
[i
], val
);
5316 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5317 unsigned long long val
= 0;
5319 for_each_mem_cgroup_tree(mi
, memcg
)
5320 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5321 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5324 #ifdef CONFIG_DEBUG_VM
5327 struct mem_cgroup_per_zone
*mz
;
5328 struct zone_reclaim_stat
*rstat
;
5329 unsigned long recent_rotated
[2] = {0, 0};
5330 unsigned long recent_scanned
[2] = {0, 0};
5332 for_each_online_node(nid
)
5333 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5334 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5335 rstat
= &mz
->lruvec
.reclaim_stat
;
5337 recent_rotated
[0] += rstat
->recent_rotated
[0];
5338 recent_rotated
[1] += rstat
->recent_rotated
[1];
5339 recent_scanned
[0] += rstat
->recent_scanned
[0];
5340 recent_scanned
[1] += rstat
->recent_scanned
[1];
5342 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5343 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5344 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5345 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5352 static u64
mem_cgroup_swappiness_read(struct cgroup
*cgrp
, struct cftype
*cft
)
5354 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5356 return mem_cgroup_swappiness(memcg
);
5359 static int mem_cgroup_swappiness_write(struct cgroup
*cgrp
, struct cftype
*cft
,
5362 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5363 struct mem_cgroup
*parent
;
5368 if (cgrp
->parent
== NULL
)
5371 parent
= mem_cgroup_from_cont(cgrp
->parent
);
5375 /* If under hierarchy, only empty-root can set this value */
5376 if ((parent
->use_hierarchy
) ||
5377 (memcg
->use_hierarchy
&& !list_empty(&cgrp
->children
))) {
5382 memcg
->swappiness
= val
;
5389 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5391 struct mem_cgroup_threshold_ary
*t
;
5397 t
= rcu_dereference(memcg
->thresholds
.primary
);
5399 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5404 usage
= mem_cgroup_usage(memcg
, swap
);
5407 * current_threshold points to threshold just below or equal to usage.
5408 * If it's not true, a threshold was crossed after last
5409 * call of __mem_cgroup_threshold().
5411 i
= t
->current_threshold
;
5414 * Iterate backward over array of thresholds starting from
5415 * current_threshold and check if a threshold is crossed.
5416 * If none of thresholds below usage is crossed, we read
5417 * only one element of the array here.
5419 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5420 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5422 /* i = current_threshold + 1 */
5426 * Iterate forward over array of thresholds starting from
5427 * current_threshold+1 and check if a threshold is crossed.
5428 * If none of thresholds above usage is crossed, we read
5429 * only one element of the array here.
5431 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5432 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5434 /* Update current_threshold */
5435 t
->current_threshold
= i
- 1;
5440 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5443 __mem_cgroup_threshold(memcg
, false);
5444 if (do_swap_account
)
5445 __mem_cgroup_threshold(memcg
, true);
5447 memcg
= parent_mem_cgroup(memcg
);
5451 static int compare_thresholds(const void *a
, const void *b
)
5453 const struct mem_cgroup_threshold
*_a
= a
;
5454 const struct mem_cgroup_threshold
*_b
= b
;
5456 return _a
->threshold
- _b
->threshold
;
5459 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5461 struct mem_cgroup_eventfd_list
*ev
;
5463 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5464 eventfd_signal(ev
->eventfd
, 1);
5468 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5470 struct mem_cgroup
*iter
;
5472 for_each_mem_cgroup_tree(iter
, memcg
)
5473 mem_cgroup_oom_notify_cb(iter
);
5476 static int mem_cgroup_usage_register_event(struct cgroup
*cgrp
,
5477 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5479 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5480 struct mem_cgroup_thresholds
*thresholds
;
5481 struct mem_cgroup_threshold_ary
*new;
5482 enum res_type type
= MEMFILE_TYPE(cft
->private);
5483 u64 threshold
, usage
;
5486 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5490 mutex_lock(&memcg
->thresholds_lock
);
5493 thresholds
= &memcg
->thresholds
;
5494 else if (type
== _MEMSWAP
)
5495 thresholds
= &memcg
->memsw_thresholds
;
5499 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5501 /* Check if a threshold crossed before adding a new one */
5502 if (thresholds
->primary
)
5503 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5505 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5507 /* Allocate memory for new array of thresholds */
5508 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5516 /* Copy thresholds (if any) to new array */
5517 if (thresholds
->primary
) {
5518 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5519 sizeof(struct mem_cgroup_threshold
));
5522 /* Add new threshold */
5523 new->entries
[size
- 1].eventfd
= eventfd
;
5524 new->entries
[size
- 1].threshold
= threshold
;
5526 /* Sort thresholds. Registering of new threshold isn't time-critical */
5527 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5528 compare_thresholds
, NULL
);
5530 /* Find current threshold */
5531 new->current_threshold
= -1;
5532 for (i
= 0; i
< size
; i
++) {
5533 if (new->entries
[i
].threshold
<= usage
) {
5535 * new->current_threshold will not be used until
5536 * rcu_assign_pointer(), so it's safe to increment
5539 ++new->current_threshold
;
5544 /* Free old spare buffer and save old primary buffer as spare */
5545 kfree(thresholds
->spare
);
5546 thresholds
->spare
= thresholds
->primary
;
5548 rcu_assign_pointer(thresholds
->primary
, new);
5550 /* To be sure that nobody uses thresholds */
5554 mutex_unlock(&memcg
->thresholds_lock
);
5559 static void mem_cgroup_usage_unregister_event(struct cgroup
*cgrp
,
5560 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5562 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5563 struct mem_cgroup_thresholds
*thresholds
;
5564 struct mem_cgroup_threshold_ary
*new;
5565 enum res_type type
= MEMFILE_TYPE(cft
->private);
5569 mutex_lock(&memcg
->thresholds_lock
);
5571 thresholds
= &memcg
->thresholds
;
5572 else if (type
== _MEMSWAP
)
5573 thresholds
= &memcg
->memsw_thresholds
;
5577 if (!thresholds
->primary
)
5580 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5582 /* Check if a threshold crossed before removing */
5583 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5585 /* Calculate new number of threshold */
5587 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5588 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5592 new = thresholds
->spare
;
5594 /* Set thresholds array to NULL if we don't have thresholds */
5603 /* Copy thresholds and find current threshold */
5604 new->current_threshold
= -1;
5605 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5606 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5609 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5610 if (new->entries
[j
].threshold
<= usage
) {
5612 * new->current_threshold will not be used
5613 * until rcu_assign_pointer(), so it's safe to increment
5616 ++new->current_threshold
;
5622 /* Swap primary and spare array */
5623 thresholds
->spare
= thresholds
->primary
;
5624 /* If all events are unregistered, free the spare array */
5626 kfree(thresholds
->spare
);
5627 thresholds
->spare
= NULL
;
5630 rcu_assign_pointer(thresholds
->primary
, new);
5632 /* To be sure that nobody uses thresholds */
5635 mutex_unlock(&memcg
->thresholds_lock
);
5638 static int mem_cgroup_oom_register_event(struct cgroup
*cgrp
,
5639 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5641 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5642 struct mem_cgroup_eventfd_list
*event
;
5643 enum res_type type
= MEMFILE_TYPE(cft
->private);
5645 BUG_ON(type
!= _OOM_TYPE
);
5646 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5650 spin_lock(&memcg_oom_lock
);
5652 event
->eventfd
= eventfd
;
5653 list_add(&event
->list
, &memcg
->oom_notify
);
5655 /* already in OOM ? */
5656 if (atomic_read(&memcg
->under_oom
))
5657 eventfd_signal(eventfd
, 1);
5658 spin_unlock(&memcg_oom_lock
);
5663 static void mem_cgroup_oom_unregister_event(struct cgroup
*cgrp
,
5664 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5666 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5667 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5668 enum res_type type
= MEMFILE_TYPE(cft
->private);
5670 BUG_ON(type
!= _OOM_TYPE
);
5672 spin_lock(&memcg_oom_lock
);
5674 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5675 if (ev
->eventfd
== eventfd
) {
5676 list_del(&ev
->list
);
5681 spin_unlock(&memcg_oom_lock
);
5684 static int mem_cgroup_oom_control_read(struct cgroup
*cgrp
,
5685 struct cftype
*cft
, struct cgroup_map_cb
*cb
)
5687 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5689 cb
->fill(cb
, "oom_kill_disable", memcg
->oom_kill_disable
);
5691 if (atomic_read(&memcg
->under_oom
))
5692 cb
->fill(cb
, "under_oom", 1);
5694 cb
->fill(cb
, "under_oom", 0);
5698 static int mem_cgroup_oom_control_write(struct cgroup
*cgrp
,
5699 struct cftype
*cft
, u64 val
)
5701 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
5702 struct mem_cgroup
*parent
;
5704 /* cannot set to root cgroup and only 0 and 1 are allowed */
5705 if (!cgrp
->parent
|| !((val
== 0) || (val
== 1)))
5708 parent
= mem_cgroup_from_cont(cgrp
->parent
);
5711 /* oom-kill-disable is a flag for subhierarchy. */
5712 if ((parent
->use_hierarchy
) ||
5713 (memcg
->use_hierarchy
&& !list_empty(&cgrp
->children
))) {
5717 memcg
->oom_kill_disable
= val
;
5719 memcg_oom_recover(memcg
);
5724 #ifdef CONFIG_MEMCG_KMEM
5725 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5729 memcg
->kmemcg_id
= -1;
5730 ret
= memcg_propagate_kmem(memcg
);
5734 return mem_cgroup_sockets_init(memcg
, ss
);
5737 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
5739 mem_cgroup_sockets_destroy(memcg
);
5741 memcg_kmem_mark_dead(memcg
);
5743 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5747 * Charges already down to 0, undo mem_cgroup_get() done in the charge
5748 * path here, being careful not to race with memcg_uncharge_kmem: it is
5749 * possible that the charges went down to 0 between mark_dead and the
5750 * res_counter read, so in that case, we don't need the put
5752 if (memcg_kmem_test_and_clear_dead(memcg
))
5753 mem_cgroup_put(memcg
);
5756 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5761 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
5766 static struct cftype mem_cgroup_files
[] = {
5768 .name
= "usage_in_bytes",
5769 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
5770 .read
= mem_cgroup_read
,
5771 .register_event
= mem_cgroup_usage_register_event
,
5772 .unregister_event
= mem_cgroup_usage_unregister_event
,
5775 .name
= "max_usage_in_bytes",
5776 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
5777 .trigger
= mem_cgroup_reset
,
5778 .read
= mem_cgroup_read
,
5781 .name
= "limit_in_bytes",
5782 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
5783 .write_string
= mem_cgroup_write
,
5784 .read
= mem_cgroup_read
,
5787 .name
= "soft_limit_in_bytes",
5788 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
5789 .write_string
= mem_cgroup_write
,
5790 .read
= mem_cgroup_read
,
5794 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
5795 .trigger
= mem_cgroup_reset
,
5796 .read
= mem_cgroup_read
,
5800 .read_seq_string
= memcg_stat_show
,
5803 .name
= "force_empty",
5804 .trigger
= mem_cgroup_force_empty_write
,
5807 .name
= "use_hierarchy",
5808 .write_u64
= mem_cgroup_hierarchy_write
,
5809 .read_u64
= mem_cgroup_hierarchy_read
,
5812 .name
= "swappiness",
5813 .read_u64
= mem_cgroup_swappiness_read
,
5814 .write_u64
= mem_cgroup_swappiness_write
,
5817 .name
= "move_charge_at_immigrate",
5818 .read_u64
= mem_cgroup_move_charge_read
,
5819 .write_u64
= mem_cgroup_move_charge_write
,
5822 .name
= "oom_control",
5823 .read_map
= mem_cgroup_oom_control_read
,
5824 .write_u64
= mem_cgroup_oom_control_write
,
5825 .register_event
= mem_cgroup_oom_register_event
,
5826 .unregister_event
= mem_cgroup_oom_unregister_event
,
5827 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
5831 .name
= "numa_stat",
5832 .read_seq_string
= memcg_numa_stat_show
,
5835 #ifdef CONFIG_MEMCG_KMEM
5837 .name
= "kmem.limit_in_bytes",
5838 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
5839 .write_string
= mem_cgroup_write
,
5840 .read
= mem_cgroup_read
,
5843 .name
= "kmem.usage_in_bytes",
5844 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
5845 .read
= mem_cgroup_read
,
5848 .name
= "kmem.failcnt",
5849 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
5850 .trigger
= mem_cgroup_reset
,
5851 .read
= mem_cgroup_read
,
5854 .name
= "kmem.max_usage_in_bytes",
5855 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
5856 .trigger
= mem_cgroup_reset
,
5857 .read
= mem_cgroup_read
,
5859 #ifdef CONFIG_SLABINFO
5861 .name
= "kmem.slabinfo",
5862 .read_seq_string
= mem_cgroup_slabinfo_read
,
5866 { }, /* terminate */
5869 #ifdef CONFIG_MEMCG_SWAP
5870 static struct cftype memsw_cgroup_files
[] = {
5872 .name
= "memsw.usage_in_bytes",
5873 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
5874 .read
= mem_cgroup_read
,
5875 .register_event
= mem_cgroup_usage_register_event
,
5876 .unregister_event
= mem_cgroup_usage_unregister_event
,
5879 .name
= "memsw.max_usage_in_bytes",
5880 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
5881 .trigger
= mem_cgroup_reset
,
5882 .read
= mem_cgroup_read
,
5885 .name
= "memsw.limit_in_bytes",
5886 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
5887 .write_string
= mem_cgroup_write
,
5888 .read
= mem_cgroup_read
,
5891 .name
= "memsw.failcnt",
5892 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
5893 .trigger
= mem_cgroup_reset
,
5894 .read
= mem_cgroup_read
,
5896 { }, /* terminate */
5899 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5901 struct mem_cgroup_per_node
*pn
;
5902 struct mem_cgroup_per_zone
*mz
;
5903 int zone
, tmp
= node
;
5905 * This routine is called against possible nodes.
5906 * But it's BUG to call kmalloc() against offline node.
5908 * TODO: this routine can waste much memory for nodes which will
5909 * never be onlined. It's better to use memory hotplug callback
5912 if (!node_state(node
, N_NORMAL_MEMORY
))
5914 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
5918 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
5919 mz
= &pn
->zoneinfo
[zone
];
5920 lruvec_init(&mz
->lruvec
);
5921 mz
->usage_in_excess
= 0;
5922 mz
->on_tree
= false;
5925 memcg
->info
.nodeinfo
[node
] = pn
;
5929 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5931 kfree(memcg
->info
.nodeinfo
[node
]);
5934 static struct mem_cgroup
*mem_cgroup_alloc(void)
5936 struct mem_cgroup
*memcg
;
5937 size_t size
= memcg_size();
5939 /* Can be very big if nr_node_ids is very big */
5940 if (size
< PAGE_SIZE
)
5941 memcg
= kzalloc(size
, GFP_KERNEL
);
5943 memcg
= vzalloc(size
);
5948 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
5951 spin_lock_init(&memcg
->pcp_counter_lock
);
5955 if (size
< PAGE_SIZE
)
5963 * At destroying mem_cgroup, references from swap_cgroup can remain.
5964 * (scanning all at force_empty is too costly...)
5966 * Instead of clearing all references at force_empty, we remember
5967 * the number of reference from swap_cgroup and free mem_cgroup when
5968 * it goes down to 0.
5970 * Removal of cgroup itself succeeds regardless of refs from swap.
5973 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
5976 size_t size
= memcg_size();
5978 mem_cgroup_remove_from_trees(memcg
);
5979 free_css_id(&mem_cgroup_subsys
, &memcg
->css
);
5982 free_mem_cgroup_per_zone_info(memcg
, node
);
5984 free_percpu(memcg
->stat
);
5987 * We need to make sure that (at least for now), the jump label
5988 * destruction code runs outside of the cgroup lock. This is because
5989 * get_online_cpus(), which is called from the static_branch update,
5990 * can't be called inside the cgroup_lock. cpusets are the ones
5991 * enforcing this dependency, so if they ever change, we might as well.
5993 * schedule_work() will guarantee this happens. Be careful if you need
5994 * to move this code around, and make sure it is outside
5997 disarm_static_keys(memcg
);
5998 if (size
< PAGE_SIZE
)
6006 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
6007 * but in process context. The work_freeing structure is overlaid
6008 * on the rcu_freeing structure, which itself is overlaid on memsw.
6010 static void free_work(struct work_struct
*work
)
6012 struct mem_cgroup
*memcg
;
6014 memcg
= container_of(work
, struct mem_cgroup
, work_freeing
);
6015 __mem_cgroup_free(memcg
);
6018 static void free_rcu(struct rcu_head
*rcu_head
)
6020 struct mem_cgroup
*memcg
;
6022 memcg
= container_of(rcu_head
, struct mem_cgroup
, rcu_freeing
);
6023 INIT_WORK(&memcg
->work_freeing
, free_work
);
6024 schedule_work(&memcg
->work_freeing
);
6027 static void mem_cgroup_get(struct mem_cgroup
*memcg
)
6029 atomic_inc(&memcg
->refcnt
);
6032 static void __mem_cgroup_put(struct mem_cgroup
*memcg
, int count
)
6034 if (atomic_sub_and_test(count
, &memcg
->refcnt
)) {
6035 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
6036 call_rcu(&memcg
->rcu_freeing
, free_rcu
);
6038 mem_cgroup_put(parent
);
6042 static void mem_cgroup_put(struct mem_cgroup
*memcg
)
6044 __mem_cgroup_put(memcg
, 1);
6048 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6050 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6052 if (!memcg
->res
.parent
)
6054 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6056 EXPORT_SYMBOL(parent_mem_cgroup
);
6058 static int mem_cgroup_soft_limit_tree_init(void)
6060 struct mem_cgroup_tree_per_node
*rtpn
;
6061 struct mem_cgroup_tree_per_zone
*rtpz
;
6062 int tmp
, node
, zone
;
6064 for_each_node(node
) {
6066 if (!node_state(node
, N_NORMAL_MEMORY
))
6068 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
6072 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6074 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6075 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
6076 rtpz
->rb_root
= RB_ROOT
;
6077 spin_lock_init(&rtpz
->lock
);
6083 for_each_node(node
) {
6084 if (!soft_limit_tree
.rb_tree_per_node
[node
])
6086 kfree(soft_limit_tree
.rb_tree_per_node
[node
]);
6087 soft_limit_tree
.rb_tree_per_node
[node
] = NULL
;
6093 static struct cgroup_subsys_state
* __ref
6094 mem_cgroup_css_alloc(struct cgroup
*cont
)
6096 struct mem_cgroup
*memcg
, *parent
;
6097 long error
= -ENOMEM
;
6100 memcg
= mem_cgroup_alloc();
6102 return ERR_PTR(error
);
6105 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6109 if (cont
->parent
== NULL
) {
6112 if (mem_cgroup_soft_limit_tree_init())
6114 root_mem_cgroup
= memcg
;
6115 for_each_possible_cpu(cpu
) {
6116 struct memcg_stock_pcp
*stock
=
6117 &per_cpu(memcg_stock
, cpu
);
6118 INIT_WORK(&stock
->work
, drain_local_stock
);
6121 parent
= mem_cgroup_from_cont(cont
->parent
);
6122 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6123 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6126 if (parent
&& parent
->use_hierarchy
) {
6127 res_counter_init(&memcg
->res
, &parent
->res
);
6128 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6129 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6132 * We increment refcnt of the parent to ensure that we can
6133 * safely access it on res_counter_charge/uncharge.
6134 * This refcnt will be decremented when freeing this
6135 * mem_cgroup(see mem_cgroup_put).
6137 mem_cgroup_get(parent
);
6139 res_counter_init(&memcg
->res
, NULL
);
6140 res_counter_init(&memcg
->memsw
, NULL
);
6141 res_counter_init(&memcg
->kmem
, NULL
);
6143 * Deeper hierachy with use_hierarchy == false doesn't make
6144 * much sense so let cgroup subsystem know about this
6145 * unfortunate state in our controller.
6147 if (parent
&& parent
!= root_mem_cgroup
)
6148 mem_cgroup_subsys
.broken_hierarchy
= true;
6150 memcg
->last_scanned_node
= MAX_NUMNODES
;
6151 INIT_LIST_HEAD(&memcg
->oom_notify
);
6154 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6155 atomic_set(&memcg
->refcnt
, 1);
6156 memcg
->move_charge_at_immigrate
= 0;
6157 mutex_init(&memcg
->thresholds_lock
);
6158 spin_lock_init(&memcg
->move_lock
);
6160 error
= memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
6163 * We call put now because our (and parent's) refcnts
6164 * are already in place. mem_cgroup_put() will internally
6165 * call __mem_cgroup_free, so return directly
6167 mem_cgroup_put(memcg
);
6168 return ERR_PTR(error
);
6172 __mem_cgroup_free(memcg
);
6173 return ERR_PTR(error
);
6176 static void mem_cgroup_css_offline(struct cgroup
*cont
)
6178 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
6180 mem_cgroup_reparent_charges(memcg
);
6181 mem_cgroup_destroy_all_caches(memcg
);
6184 static void mem_cgroup_css_free(struct cgroup
*cont
)
6186 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
6188 kmem_cgroup_destroy(memcg
);
6190 mem_cgroup_put(memcg
);
6194 /* Handlers for move charge at task migration. */
6195 #define PRECHARGE_COUNT_AT_ONCE 256
6196 static int mem_cgroup_do_precharge(unsigned long count
)
6199 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6200 struct mem_cgroup
*memcg
= mc
.to
;
6202 if (mem_cgroup_is_root(memcg
)) {
6203 mc
.precharge
+= count
;
6204 /* we don't need css_get for root */
6207 /* try to charge at once */
6209 struct res_counter
*dummy
;
6211 * "memcg" cannot be under rmdir() because we've already checked
6212 * by cgroup_lock_live_cgroup() that it is not removed and we
6213 * are still under the same cgroup_mutex. So we can postpone
6216 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6218 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6219 PAGE_SIZE
* count
, &dummy
)) {
6220 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6223 mc
.precharge
+= count
;
6227 /* fall back to one by one charge */
6229 if (signal_pending(current
)) {
6233 if (!batch_count
--) {
6234 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6237 ret
= __mem_cgroup_try_charge(NULL
,
6238 GFP_KERNEL
, 1, &memcg
, false);
6240 /* mem_cgroup_clear_mc() will do uncharge later */
6248 * get_mctgt_type - get target type of moving charge
6249 * @vma: the vma the pte to be checked belongs
6250 * @addr: the address corresponding to the pte to be checked
6251 * @ptent: the pte to be checked
6252 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6255 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6256 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6257 * move charge. if @target is not NULL, the page is stored in target->page
6258 * with extra refcnt got(Callers should handle it).
6259 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6260 * target for charge migration. if @target is not NULL, the entry is stored
6263 * Called with pte lock held.
6270 enum mc_target_type
{
6276 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6277 unsigned long addr
, pte_t ptent
)
6279 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6281 if (!page
|| !page_mapped(page
))
6283 if (PageAnon(page
)) {
6284 /* we don't move shared anon */
6287 } else if (!move_file())
6288 /* we ignore mapcount for file pages */
6290 if (!get_page_unless_zero(page
))
6297 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6298 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6300 struct page
*page
= NULL
;
6301 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6303 if (!move_anon() || non_swap_entry(ent
))
6306 * Because lookup_swap_cache() updates some statistics counter,
6307 * we call find_get_page() with swapper_space directly.
6309 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6310 if (do_swap_account
)
6311 entry
->val
= ent
.val
;
6316 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6317 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6323 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6324 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6326 struct page
*page
= NULL
;
6327 struct address_space
*mapping
;
6330 if (!vma
->vm_file
) /* anonymous vma */
6335 mapping
= vma
->vm_file
->f_mapping
;
6336 if (pte_none(ptent
))
6337 pgoff
= linear_page_index(vma
, addr
);
6338 else /* pte_file(ptent) is true */
6339 pgoff
= pte_to_pgoff(ptent
);
6341 /* page is moved even if it's not RSS of this task(page-faulted). */
6342 page
= find_get_page(mapping
, pgoff
);
6345 /* shmem/tmpfs may report page out on swap: account for that too. */
6346 if (radix_tree_exceptional_entry(page
)) {
6347 swp_entry_t swap
= radix_to_swp_entry(page
);
6348 if (do_swap_account
)
6350 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6356 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6357 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6359 struct page
*page
= NULL
;
6360 struct page_cgroup
*pc
;
6361 enum mc_target_type ret
= MC_TARGET_NONE
;
6362 swp_entry_t ent
= { .val
= 0 };
6364 if (pte_present(ptent
))
6365 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6366 else if (is_swap_pte(ptent
))
6367 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6368 else if (pte_none(ptent
) || pte_file(ptent
))
6369 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6371 if (!page
&& !ent
.val
)
6374 pc
= lookup_page_cgroup(page
);
6376 * Do only loose check w/o page_cgroup lock.
6377 * mem_cgroup_move_account() checks the pc is valid or not under
6380 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6381 ret
= MC_TARGET_PAGE
;
6383 target
->page
= page
;
6385 if (!ret
|| !target
)
6388 /* There is a swap entry and a page doesn't exist or isn't charged */
6389 if (ent
.val
&& !ret
&&
6390 css_id(&mc
.from
->css
) == lookup_swap_cgroup_id(ent
)) {
6391 ret
= MC_TARGET_SWAP
;
6398 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6400 * We don't consider swapping or file mapped pages because THP does not
6401 * support them for now.
6402 * Caller should make sure that pmd_trans_huge(pmd) is true.
6404 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6405 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6407 struct page
*page
= NULL
;
6408 struct page_cgroup
*pc
;
6409 enum mc_target_type ret
= MC_TARGET_NONE
;
6411 page
= pmd_page(pmd
);
6412 VM_BUG_ON(!page
|| !PageHead(page
));
6415 pc
= lookup_page_cgroup(page
);
6416 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6417 ret
= MC_TARGET_PAGE
;
6420 target
->page
= page
;
6426 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6427 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6429 return MC_TARGET_NONE
;
6433 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6434 unsigned long addr
, unsigned long end
,
6435 struct mm_walk
*walk
)
6437 struct vm_area_struct
*vma
= walk
->private;
6441 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6442 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6443 mc
.precharge
+= HPAGE_PMD_NR
;
6444 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6448 if (pmd_trans_unstable(pmd
))
6450 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6451 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6452 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6453 mc
.precharge
++; /* increment precharge temporarily */
6454 pte_unmap_unlock(pte
- 1, ptl
);
6460 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6462 unsigned long precharge
;
6463 struct vm_area_struct
*vma
;
6465 down_read(&mm
->mmap_sem
);
6466 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6467 struct mm_walk mem_cgroup_count_precharge_walk
= {
6468 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6472 if (is_vm_hugetlb_page(vma
))
6474 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6475 &mem_cgroup_count_precharge_walk
);
6477 up_read(&mm
->mmap_sem
);
6479 precharge
= mc
.precharge
;
6485 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6487 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6489 VM_BUG_ON(mc
.moving_task
);
6490 mc
.moving_task
= current
;
6491 return mem_cgroup_do_precharge(precharge
);
6494 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6495 static void __mem_cgroup_clear_mc(void)
6497 struct mem_cgroup
*from
= mc
.from
;
6498 struct mem_cgroup
*to
= mc
.to
;
6500 /* we must uncharge all the leftover precharges from mc.to */
6502 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6506 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6507 * we must uncharge here.
6509 if (mc
.moved_charge
) {
6510 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6511 mc
.moved_charge
= 0;
6513 /* we must fixup refcnts and charges */
6514 if (mc
.moved_swap
) {
6515 /* uncharge swap account from the old cgroup */
6516 if (!mem_cgroup_is_root(mc
.from
))
6517 res_counter_uncharge(&mc
.from
->memsw
,
6518 PAGE_SIZE
* mc
.moved_swap
);
6519 __mem_cgroup_put(mc
.from
, mc
.moved_swap
);
6521 if (!mem_cgroup_is_root(mc
.to
)) {
6523 * we charged both to->res and to->memsw, so we should
6526 res_counter_uncharge(&mc
.to
->res
,
6527 PAGE_SIZE
* mc
.moved_swap
);
6529 /* we've already done mem_cgroup_get(mc.to) */
6532 memcg_oom_recover(from
);
6533 memcg_oom_recover(to
);
6534 wake_up_all(&mc
.waitq
);
6537 static void mem_cgroup_clear_mc(void)
6539 struct mem_cgroup
*from
= mc
.from
;
6542 * we must clear moving_task before waking up waiters at the end of
6545 mc
.moving_task
= NULL
;
6546 __mem_cgroup_clear_mc();
6547 spin_lock(&mc
.lock
);
6550 spin_unlock(&mc
.lock
);
6551 mem_cgroup_end_move(from
);
6554 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
6555 struct cgroup_taskset
*tset
)
6557 struct task_struct
*p
= cgroup_taskset_first(tset
);
6559 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgroup
);
6560 unsigned long move_charge_at_immigrate
;
6563 * We are now commited to this value whatever it is. Changes in this
6564 * tunable will only affect upcoming migrations, not the current one.
6565 * So we need to save it, and keep it going.
6567 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
6568 if (move_charge_at_immigrate
) {
6569 struct mm_struct
*mm
;
6570 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
6572 VM_BUG_ON(from
== memcg
);
6574 mm
= get_task_mm(p
);
6577 /* We move charges only when we move a owner of the mm */
6578 if (mm
->owner
== p
) {
6581 VM_BUG_ON(mc
.precharge
);
6582 VM_BUG_ON(mc
.moved_charge
);
6583 VM_BUG_ON(mc
.moved_swap
);
6584 mem_cgroup_start_move(from
);
6585 spin_lock(&mc
.lock
);
6588 mc
.immigrate_flags
= move_charge_at_immigrate
;
6589 spin_unlock(&mc
.lock
);
6590 /* We set mc.moving_task later */
6592 ret
= mem_cgroup_precharge_mc(mm
);
6594 mem_cgroup_clear_mc();
6601 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
6602 struct cgroup_taskset
*tset
)
6604 mem_cgroup_clear_mc();
6607 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
6608 unsigned long addr
, unsigned long end
,
6609 struct mm_walk
*walk
)
6612 struct vm_area_struct
*vma
= walk
->private;
6615 enum mc_target_type target_type
;
6616 union mc_target target
;
6618 struct page_cgroup
*pc
;
6621 * We don't take compound_lock() here but no race with splitting thp
6623 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6624 * under splitting, which means there's no concurrent thp split,
6625 * - if another thread runs into split_huge_page() just after we
6626 * entered this if-block, the thread must wait for page table lock
6627 * to be unlocked in __split_huge_page_splitting(), where the main
6628 * part of thp split is not executed yet.
6630 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6631 if (mc
.precharge
< HPAGE_PMD_NR
) {
6632 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6635 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
6636 if (target_type
== MC_TARGET_PAGE
) {
6638 if (!isolate_lru_page(page
)) {
6639 pc
= lookup_page_cgroup(page
);
6640 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
6641 pc
, mc
.from
, mc
.to
)) {
6642 mc
.precharge
-= HPAGE_PMD_NR
;
6643 mc
.moved_charge
+= HPAGE_PMD_NR
;
6645 putback_lru_page(page
);
6649 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6653 if (pmd_trans_unstable(pmd
))
6656 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6657 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
6658 pte_t ptent
= *(pte
++);
6664 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
6665 case MC_TARGET_PAGE
:
6667 if (isolate_lru_page(page
))
6669 pc
= lookup_page_cgroup(page
);
6670 if (!mem_cgroup_move_account(page
, 1, pc
,
6673 /* we uncharge from mc.from later. */
6676 putback_lru_page(page
);
6677 put
: /* get_mctgt_type() gets the page */
6680 case MC_TARGET_SWAP
:
6682 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
6684 /* we fixup refcnts and charges later. */
6692 pte_unmap_unlock(pte
- 1, ptl
);
6697 * We have consumed all precharges we got in can_attach().
6698 * We try charge one by one, but don't do any additional
6699 * charges to mc.to if we have failed in charge once in attach()
6702 ret
= mem_cgroup_do_precharge(1);
6710 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
6712 struct vm_area_struct
*vma
;
6714 lru_add_drain_all();
6716 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
6718 * Someone who are holding the mmap_sem might be waiting in
6719 * waitq. So we cancel all extra charges, wake up all waiters,
6720 * and retry. Because we cancel precharges, we might not be able
6721 * to move enough charges, but moving charge is a best-effort
6722 * feature anyway, so it wouldn't be a big problem.
6724 __mem_cgroup_clear_mc();
6728 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6730 struct mm_walk mem_cgroup_move_charge_walk
= {
6731 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
6735 if (is_vm_hugetlb_page(vma
))
6737 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
6738 &mem_cgroup_move_charge_walk
);
6741 * means we have consumed all precharges and failed in
6742 * doing additional charge. Just abandon here.
6746 up_read(&mm
->mmap_sem
);
6749 static void mem_cgroup_move_task(struct cgroup
*cont
,
6750 struct cgroup_taskset
*tset
)
6752 struct task_struct
*p
= cgroup_taskset_first(tset
);
6753 struct mm_struct
*mm
= get_task_mm(p
);
6757 mem_cgroup_move_charge(mm
);
6761 mem_cgroup_clear_mc();
6763 #else /* !CONFIG_MMU */
6764 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
6765 struct cgroup_taskset
*tset
)
6769 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
6770 struct cgroup_taskset
*tset
)
6773 static void mem_cgroup_move_task(struct cgroup
*cont
,
6774 struct cgroup_taskset
*tset
)
6779 struct cgroup_subsys mem_cgroup_subsys
= {
6781 .subsys_id
= mem_cgroup_subsys_id
,
6782 .css_alloc
= mem_cgroup_css_alloc
,
6783 .css_offline
= mem_cgroup_css_offline
,
6784 .css_free
= mem_cgroup_css_free
,
6785 .can_attach
= mem_cgroup_can_attach
,
6786 .cancel_attach
= mem_cgroup_cancel_attach
,
6787 .attach
= mem_cgroup_move_task
,
6788 .base_cftypes
= mem_cgroup_files
,
6793 #ifdef CONFIG_MEMCG_SWAP
6794 static int __init
enable_swap_account(char *s
)
6796 /* consider enabled if no parameter or 1 is given */
6797 if (!strcmp(s
, "1"))
6798 really_do_swap_account
= 1;
6799 else if (!strcmp(s
, "0"))
6800 really_do_swap_account
= 0;
6803 __setup("swapaccount=", enable_swap_account
);
6805 static void __init
memsw_file_init(void)
6807 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys
, memsw_cgroup_files
));
6810 static void __init
enable_swap_cgroup(void)
6812 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6813 do_swap_account
= 1;
6819 static void __init
enable_swap_cgroup(void)
6825 * The rest of init is performed during ->css_alloc() for root css which
6826 * happens before initcalls. hotcpu_notifier() can't be done together as
6827 * it would introduce circular locking by adding cgroup_lock -> cpu hotplug
6828 * dependency. Do it from a subsys_initcall().
6830 static int __init
mem_cgroup_init(void)
6832 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
6833 enable_swap_cgroup();
6836 subsys_initcall(mem_cgroup_init
);