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/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/page_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
60 #include <net/tcp_memcontrol.h>
62 #include <asm/uaccess.h>
64 #include <trace/events/vmscan.h>
66 struct cgroup_subsys mem_cgroup_subsys __read_mostly
;
67 EXPORT_SYMBOL(mem_cgroup_subsys
);
69 #define MEM_CGROUP_RECLAIM_RETRIES 5
70 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
72 #ifdef CONFIG_MEMCG_SWAP
73 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
74 int do_swap_account __read_mostly
;
76 /* for remember boot option*/
77 #ifdef CONFIG_MEMCG_SWAP_ENABLED
78 static int really_do_swap_account __initdata
= 1;
80 static int really_do_swap_account __initdata
= 0;
84 #define do_swap_account 0
89 * Statistics for memory cgroup.
91 enum mem_cgroup_stat_index
{
93 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
95 MEM_CGROUP_STAT_CACHE
, /* # of pages charged as cache */
96 MEM_CGROUP_STAT_RSS
, /* # of pages charged as anon rss */
97 MEM_CGROUP_STAT_RSS_HUGE
, /* # of pages charged as anon huge */
98 MEM_CGROUP_STAT_FILE_MAPPED
, /* # of pages charged as file rss */
99 MEM_CGROUP_STAT_SWAP
, /* # of pages, swapped out */
100 MEM_CGROUP_STAT_NSTATS
,
103 static const char * const mem_cgroup_stat_names
[] = {
111 enum mem_cgroup_events_index
{
112 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
113 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
114 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
115 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
116 MEM_CGROUP_EVENTS_NSTATS
,
119 static const char * const mem_cgroup_events_names
[] = {
126 static const char * const mem_cgroup_lru_names
[] = {
135 * Per memcg event counter is incremented at every pagein/pageout. With THP,
136 * it will be incremated by the number of pages. This counter is used for
137 * for trigger some periodic events. This is straightforward and better
138 * than using jiffies etc. to handle periodic memcg event.
140 enum mem_cgroup_events_target
{
141 MEM_CGROUP_TARGET_THRESH
,
142 MEM_CGROUP_TARGET_SOFTLIMIT
,
143 MEM_CGROUP_TARGET_NUMAINFO
,
146 #define THRESHOLDS_EVENTS_TARGET 128
147 #define SOFTLIMIT_EVENTS_TARGET 1024
148 #define NUMAINFO_EVENTS_TARGET 1024
150 struct mem_cgroup_stat_cpu
{
151 long count
[MEM_CGROUP_STAT_NSTATS
];
152 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
153 unsigned long nr_page_events
;
154 unsigned long targets
[MEM_CGROUP_NTARGETS
];
157 struct mem_cgroup_reclaim_iter
{
159 * last scanned hierarchy member. Valid only if last_dead_count
160 * matches memcg->dead_count of the hierarchy root group.
162 struct mem_cgroup
*last_visited
;
163 unsigned long last_dead_count
;
165 /* scan generation, increased every round-trip */
166 unsigned int generation
;
170 * per-zone information in memory controller.
172 struct mem_cgroup_per_zone
{
173 struct lruvec lruvec
;
174 unsigned long lru_size
[NR_LRU_LISTS
];
176 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
178 struct rb_node tree_node
; /* RB tree node */
179 unsigned long long usage_in_excess
;/* Set to the value by which */
180 /* the soft limit is exceeded*/
182 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
183 /* use container_of */
186 struct mem_cgroup_per_node
{
187 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
191 * Cgroups above their limits are maintained in a RB-Tree, independent of
192 * their hierarchy representation
195 struct mem_cgroup_tree_per_zone
{
196 struct rb_root rb_root
;
200 struct mem_cgroup_tree_per_node
{
201 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
204 struct mem_cgroup_tree
{
205 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
208 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
210 struct mem_cgroup_threshold
{
211 struct eventfd_ctx
*eventfd
;
216 struct mem_cgroup_threshold_ary
{
217 /* An array index points to threshold just below or equal to usage. */
218 int current_threshold
;
219 /* Size of entries[] */
221 /* Array of thresholds */
222 struct mem_cgroup_threshold entries
[0];
225 struct mem_cgroup_thresholds
{
226 /* Primary thresholds array */
227 struct mem_cgroup_threshold_ary
*primary
;
229 * Spare threshold array.
230 * This is needed to make mem_cgroup_unregister_event() "never fail".
231 * It must be able to store at least primary->size - 1 entries.
233 struct mem_cgroup_threshold_ary
*spare
;
237 struct mem_cgroup_eventfd_list
{
238 struct list_head list
;
239 struct eventfd_ctx
*eventfd
;
242 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
243 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
246 * The memory controller data structure. The memory controller controls both
247 * page cache and RSS per cgroup. We would eventually like to provide
248 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
249 * to help the administrator determine what knobs to tune.
251 * TODO: Add a water mark for the memory controller. Reclaim will begin when
252 * we hit the water mark. May be even add a low water mark, such that
253 * no reclaim occurs from a cgroup at it's low water mark, this is
254 * a feature that will be implemented much later in the future.
257 struct cgroup_subsys_state css
;
259 * the counter to account for memory usage
261 struct res_counter res
;
263 /* vmpressure notifications */
264 struct vmpressure vmpressure
;
267 * the counter to account for mem+swap usage.
269 struct res_counter memsw
;
272 * the counter to account for kernel memory usage.
274 struct res_counter kmem
;
276 * Should the accounting and control be hierarchical, per subtree?
279 unsigned long kmem_account_flags
; /* See KMEM_ACCOUNTED_*, below */
285 /* OOM-Killer disable */
286 int oom_kill_disable
;
288 /* set when res.limit == memsw.limit */
289 bool memsw_is_minimum
;
291 /* protect arrays of thresholds */
292 struct mutex thresholds_lock
;
294 /* thresholds for memory usage. RCU-protected */
295 struct mem_cgroup_thresholds thresholds
;
297 /* thresholds for mem+swap usage. RCU-protected */
298 struct mem_cgroup_thresholds memsw_thresholds
;
300 /* For oom notifier event fd */
301 struct list_head oom_notify
;
304 * Should we move charges of a task when a task is moved into this
305 * mem_cgroup ? And what type of charges should we move ?
307 unsigned long move_charge_at_immigrate
;
309 * set > 0 if pages under this cgroup are moving to other cgroup.
311 atomic_t moving_account
;
312 /* taken only while moving_account > 0 */
313 spinlock_t move_lock
;
317 struct mem_cgroup_stat_cpu __percpu
*stat
;
319 * used when a cpu is offlined or other synchronizations
320 * See mem_cgroup_read_stat().
322 struct mem_cgroup_stat_cpu nocpu_base
;
323 spinlock_t pcp_counter_lock
;
326 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
327 struct tcp_memcontrol tcp_mem
;
329 #if defined(CONFIG_MEMCG_KMEM)
330 /* analogous to slab_common's slab_caches list. per-memcg */
331 struct list_head memcg_slab_caches
;
332 /* Not a spinlock, we can take a lot of time walking the list */
333 struct mutex slab_caches_mutex
;
334 /* Index in the kmem_cache->memcg_params->memcg_caches array */
338 int last_scanned_node
;
340 nodemask_t scan_nodes
;
341 atomic_t numainfo_events
;
342 atomic_t numainfo_updating
;
345 struct mem_cgroup_per_node
*nodeinfo
[0];
346 /* WARNING: nodeinfo must be the last member here */
349 static size_t memcg_size(void)
351 return sizeof(struct mem_cgroup
) +
352 nr_node_ids
* sizeof(struct mem_cgroup_per_node
);
355 /* internal only representation about the status of kmem accounting. */
357 KMEM_ACCOUNTED_ACTIVE
= 0, /* accounted by this cgroup itself */
358 KMEM_ACCOUNTED_ACTIVATED
, /* static key enabled. */
359 KMEM_ACCOUNTED_DEAD
, /* dead memcg with pending kmem charges */
362 /* We account when limit is on, but only after call sites are patched */
363 #define KMEM_ACCOUNTED_MASK \
364 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
366 #ifdef CONFIG_MEMCG_KMEM
367 static inline void memcg_kmem_set_active(struct mem_cgroup
*memcg
)
369 set_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
372 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
374 return test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
377 static void memcg_kmem_set_activated(struct mem_cgroup
*memcg
)
379 set_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
382 static void memcg_kmem_clear_activated(struct mem_cgroup
*memcg
)
384 clear_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
387 static void memcg_kmem_mark_dead(struct mem_cgroup
*memcg
)
390 * Our caller must use css_get() first, because memcg_uncharge_kmem()
391 * will call css_put() if it sees the memcg is dead.
394 if (test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
))
395 set_bit(KMEM_ACCOUNTED_DEAD
, &memcg
->kmem_account_flags
);
398 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup
*memcg
)
400 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD
,
401 &memcg
->kmem_account_flags
);
405 /* Stuffs for move charges at task migration. */
407 * Types of charges to be moved. "move_charge_at_immitgrate" and
408 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
411 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
412 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
416 /* "mc" and its members are protected by cgroup_mutex */
417 static struct move_charge_struct
{
418 spinlock_t lock
; /* for from, to */
419 struct mem_cgroup
*from
;
420 struct mem_cgroup
*to
;
421 unsigned long immigrate_flags
;
422 unsigned long precharge
;
423 unsigned long moved_charge
;
424 unsigned long moved_swap
;
425 struct task_struct
*moving_task
; /* a task moving charges */
426 wait_queue_head_t waitq
; /* a waitq for other context */
428 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
429 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
432 static bool move_anon(void)
434 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
437 static bool move_file(void)
439 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
443 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
444 * limit reclaim to prevent infinite loops, if they ever occur.
446 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
447 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
450 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
451 MEM_CGROUP_CHARGE_TYPE_ANON
,
452 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
453 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
457 /* for encoding cft->private value on file */
465 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
466 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
467 #define MEMFILE_ATTR(val) ((val) & 0xffff)
468 /* Used for OOM nofiier */
469 #define OOM_CONTROL (0)
472 * Reclaim flags for mem_cgroup_hierarchical_reclaim
474 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
475 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
476 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
477 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
480 * The memcg_create_mutex will be held whenever a new cgroup is created.
481 * As a consequence, any change that needs to protect against new child cgroups
482 * appearing has to hold it as well.
484 static DEFINE_MUTEX(memcg_create_mutex
);
486 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
488 return s
? container_of(s
, struct mem_cgroup
, css
) : NULL
;
491 /* Some nice accessors for the vmpressure. */
492 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
495 memcg
= root_mem_cgroup
;
496 return &memcg
->vmpressure
;
499 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
501 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
504 struct vmpressure
*css_to_vmpressure(struct cgroup_subsys_state
*css
)
506 return &mem_cgroup_from_css(css
)->vmpressure
;
509 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
511 return (memcg
== root_mem_cgroup
);
514 /* Writing them here to avoid exposing memcg's inner layout */
515 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
517 void sock_update_memcg(struct sock
*sk
)
519 if (mem_cgroup_sockets_enabled
) {
520 struct mem_cgroup
*memcg
;
521 struct cg_proto
*cg_proto
;
523 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
525 /* Socket cloning can throw us here with sk_cgrp already
526 * filled. It won't however, necessarily happen from
527 * process context. So the test for root memcg given
528 * the current task's memcg won't help us in this case.
530 * Respecting the original socket's memcg is a better
531 * decision in this case.
534 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
535 css_get(&sk
->sk_cgrp
->memcg
->css
);
540 memcg
= mem_cgroup_from_task(current
);
541 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
542 if (!mem_cgroup_is_root(memcg
) &&
543 memcg_proto_active(cg_proto
) && css_tryget(&memcg
->css
)) {
544 sk
->sk_cgrp
= cg_proto
;
549 EXPORT_SYMBOL(sock_update_memcg
);
551 void sock_release_memcg(struct sock
*sk
)
553 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
554 struct mem_cgroup
*memcg
;
555 WARN_ON(!sk
->sk_cgrp
->memcg
);
556 memcg
= sk
->sk_cgrp
->memcg
;
557 css_put(&sk
->sk_cgrp
->memcg
->css
);
561 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
563 if (!memcg
|| mem_cgroup_is_root(memcg
))
566 return &memcg
->tcp_mem
.cg_proto
;
568 EXPORT_SYMBOL(tcp_proto_cgroup
);
570 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
572 if (!memcg_proto_activated(&memcg
->tcp_mem
.cg_proto
))
574 static_key_slow_dec(&memcg_socket_limit_enabled
);
577 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
582 #ifdef CONFIG_MEMCG_KMEM
584 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
585 * There are two main reasons for not using the css_id for this:
586 * 1) this works better in sparse environments, where we have a lot of memcgs,
587 * but only a few kmem-limited. Or also, if we have, for instance, 200
588 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
589 * 200 entry array for that.
591 * 2) In order not to violate the cgroup API, we would like to do all memory
592 * allocation in ->create(). At that point, we haven't yet allocated the
593 * css_id. Having a separate index prevents us from messing with the cgroup
596 * The current size of the caches array is stored in
597 * memcg_limited_groups_array_size. It will double each time we have to
600 static DEFINE_IDA(kmem_limited_groups
);
601 int memcg_limited_groups_array_size
;
604 * MIN_SIZE is different than 1, because we would like to avoid going through
605 * the alloc/free process all the time. In a small machine, 4 kmem-limited
606 * cgroups is a reasonable guess. In the future, it could be a parameter or
607 * tunable, but that is strictly not necessary.
609 * MAX_SIZE should be as large as the number of css_ids. Ideally, we could get
610 * this constant directly from cgroup, but it is understandable that this is
611 * better kept as an internal representation in cgroup.c. In any case, the
612 * css_id space is not getting any smaller, and we don't have to necessarily
613 * increase ours as well if it increases.
615 #define MEMCG_CACHES_MIN_SIZE 4
616 #define MEMCG_CACHES_MAX_SIZE 65535
619 * A lot of the calls to the cache allocation functions are expected to be
620 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
621 * conditional to this static branch, we'll have to allow modules that does
622 * kmem_cache_alloc and the such to see this symbol as well
624 struct static_key memcg_kmem_enabled_key
;
625 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
627 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
629 if (memcg_kmem_is_active(memcg
)) {
630 static_key_slow_dec(&memcg_kmem_enabled_key
);
631 ida_simple_remove(&kmem_limited_groups
, memcg
->kmemcg_id
);
634 * This check can't live in kmem destruction function,
635 * since the charges will outlive the cgroup
637 WARN_ON(res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0);
640 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
643 #endif /* CONFIG_MEMCG_KMEM */
645 static void disarm_static_keys(struct mem_cgroup
*memcg
)
647 disarm_sock_keys(memcg
);
648 disarm_kmem_keys(memcg
);
651 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
653 static struct mem_cgroup_per_zone
*
654 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
656 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
657 return &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
660 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
665 static struct mem_cgroup_per_zone
*
666 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
668 int nid
= page_to_nid(page
);
669 int zid
= page_zonenum(page
);
671 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
674 static struct mem_cgroup_tree_per_zone
*
675 soft_limit_tree_node_zone(int nid
, int zid
)
677 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
680 static struct mem_cgroup_tree_per_zone
*
681 soft_limit_tree_from_page(struct page
*page
)
683 int nid
= page_to_nid(page
);
684 int zid
= page_zonenum(page
);
686 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
690 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
691 struct mem_cgroup_per_zone
*mz
,
692 struct mem_cgroup_tree_per_zone
*mctz
,
693 unsigned long long new_usage_in_excess
)
695 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
696 struct rb_node
*parent
= NULL
;
697 struct mem_cgroup_per_zone
*mz_node
;
702 mz
->usage_in_excess
= new_usage_in_excess
;
703 if (!mz
->usage_in_excess
)
707 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
709 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
712 * We can't avoid mem cgroups that are over their soft
713 * limit by the same amount
715 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
718 rb_link_node(&mz
->tree_node
, parent
, p
);
719 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
724 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
725 struct mem_cgroup_per_zone
*mz
,
726 struct mem_cgroup_tree_per_zone
*mctz
)
730 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
735 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
736 struct mem_cgroup_per_zone
*mz
,
737 struct mem_cgroup_tree_per_zone
*mctz
)
739 spin_lock(&mctz
->lock
);
740 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
741 spin_unlock(&mctz
->lock
);
745 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
747 unsigned long long excess
;
748 struct mem_cgroup_per_zone
*mz
;
749 struct mem_cgroup_tree_per_zone
*mctz
;
750 int nid
= page_to_nid(page
);
751 int zid
= page_zonenum(page
);
752 mctz
= soft_limit_tree_from_page(page
);
755 * Necessary to update all ancestors when hierarchy is used.
756 * because their event counter is not touched.
758 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
759 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
760 excess
= res_counter_soft_limit_excess(&memcg
->res
);
762 * We have to update the tree if mz is on RB-tree or
763 * mem is over its softlimit.
765 if (excess
|| mz
->on_tree
) {
766 spin_lock(&mctz
->lock
);
767 /* if on-tree, remove it */
769 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
771 * Insert again. mz->usage_in_excess will be updated.
772 * If excess is 0, no tree ops.
774 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
775 spin_unlock(&mctz
->lock
);
780 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
783 struct mem_cgroup_per_zone
*mz
;
784 struct mem_cgroup_tree_per_zone
*mctz
;
786 for_each_node(node
) {
787 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
788 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
789 mctz
= soft_limit_tree_node_zone(node
, zone
);
790 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
795 static struct mem_cgroup_per_zone
*
796 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
798 struct rb_node
*rightmost
= NULL
;
799 struct mem_cgroup_per_zone
*mz
;
803 rightmost
= rb_last(&mctz
->rb_root
);
805 goto done
; /* Nothing to reclaim from */
807 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
809 * Remove the node now but someone else can add it back,
810 * we will to add it back at the end of reclaim to its correct
811 * position in the tree.
813 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
814 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
815 !css_tryget(&mz
->memcg
->css
))
821 static struct mem_cgroup_per_zone
*
822 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
824 struct mem_cgroup_per_zone
*mz
;
826 spin_lock(&mctz
->lock
);
827 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
828 spin_unlock(&mctz
->lock
);
833 * Implementation Note: reading percpu statistics for memcg.
835 * Both of vmstat[] and percpu_counter has threshold and do periodic
836 * synchronization to implement "quick" read. There are trade-off between
837 * reading cost and precision of value. Then, we may have a chance to implement
838 * a periodic synchronizion of counter in memcg's counter.
840 * But this _read() function is used for user interface now. The user accounts
841 * memory usage by memory cgroup and he _always_ requires exact value because
842 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
843 * have to visit all online cpus and make sum. So, for now, unnecessary
844 * synchronization is not implemented. (just implemented for cpu hotplug)
846 * If there are kernel internal actions which can make use of some not-exact
847 * value, and reading all cpu value can be performance bottleneck in some
848 * common workload, threashold and synchonization as vmstat[] should be
851 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
852 enum mem_cgroup_stat_index idx
)
858 for_each_online_cpu(cpu
)
859 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
860 #ifdef CONFIG_HOTPLUG_CPU
861 spin_lock(&memcg
->pcp_counter_lock
);
862 val
+= memcg
->nocpu_base
.count
[idx
];
863 spin_unlock(&memcg
->pcp_counter_lock
);
869 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
872 int val
= (charge
) ? 1 : -1;
873 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
876 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
877 enum mem_cgroup_events_index idx
)
879 unsigned long val
= 0;
882 for_each_online_cpu(cpu
)
883 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
884 #ifdef CONFIG_HOTPLUG_CPU
885 spin_lock(&memcg
->pcp_counter_lock
);
886 val
+= memcg
->nocpu_base
.events
[idx
];
887 spin_unlock(&memcg
->pcp_counter_lock
);
892 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
894 bool anon
, int nr_pages
)
899 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
900 * counted as CACHE even if it's on ANON LRU.
903 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
906 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
909 if (PageTransHuge(page
))
910 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
913 /* pagein of a big page is an event. So, ignore page size */
915 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
917 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
918 nr_pages
= -nr_pages
; /* for event */
921 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
927 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
929 struct mem_cgroup_per_zone
*mz
;
931 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
932 return mz
->lru_size
[lru
];
936 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
937 unsigned int lru_mask
)
939 struct mem_cgroup_per_zone
*mz
;
941 unsigned long ret
= 0;
943 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
946 if (BIT(lru
) & lru_mask
)
947 ret
+= mz
->lru_size
[lru
];
953 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
954 int nid
, unsigned int lru_mask
)
959 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
960 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
966 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
967 unsigned int lru_mask
)
972 for_each_node_state(nid
, N_MEMORY
)
973 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
977 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
978 enum mem_cgroup_events_target target
)
980 unsigned long val
, next
;
982 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
983 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
984 /* from time_after() in jiffies.h */
985 if ((long)next
- (long)val
< 0) {
987 case MEM_CGROUP_TARGET_THRESH
:
988 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
990 case MEM_CGROUP_TARGET_SOFTLIMIT
:
991 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
993 case MEM_CGROUP_TARGET_NUMAINFO
:
994 next
= val
+ NUMAINFO_EVENTS_TARGET
;
999 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
1006 * Check events in order.
1009 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
1012 /* threshold event is triggered in finer grain than soft limit */
1013 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1014 MEM_CGROUP_TARGET_THRESH
))) {
1016 bool do_numainfo __maybe_unused
;
1018 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1019 MEM_CGROUP_TARGET_SOFTLIMIT
);
1020 #if MAX_NUMNODES > 1
1021 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1022 MEM_CGROUP_TARGET_NUMAINFO
);
1026 mem_cgroup_threshold(memcg
);
1027 if (unlikely(do_softlimit
))
1028 mem_cgroup_update_tree(memcg
, page
);
1029 #if MAX_NUMNODES > 1
1030 if (unlikely(do_numainfo
))
1031 atomic_inc(&memcg
->numainfo_events
);
1037 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1040 * mm_update_next_owner() may clear mm->owner to NULL
1041 * if it races with swapoff, page migration, etc.
1042 * So this can be called with p == NULL.
1047 return mem_cgroup_from_css(task_css(p
, mem_cgroup_subsys_id
));
1050 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1052 struct mem_cgroup
*memcg
= NULL
;
1057 * Because we have no locks, mm->owner's may be being moved to other
1058 * cgroup. We use css_tryget() here even if this looks
1059 * pessimistic (rather than adding locks here).
1063 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1064 if (unlikely(!memcg
))
1066 } while (!css_tryget(&memcg
->css
));
1072 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1073 * ref. count) or NULL if the whole root's subtree has been visited.
1075 * helper function to be used by mem_cgroup_iter
1077 static struct mem_cgroup
*__mem_cgroup_iter_next(struct mem_cgroup
*root
,
1078 struct mem_cgroup
*last_visited
)
1080 struct cgroup_subsys_state
*prev_css
, *next_css
;
1082 prev_css
= last_visited
? &last_visited
->css
: NULL
;
1084 next_css
= css_next_descendant_pre(prev_css
, &root
->css
);
1087 * Even if we found a group we have to make sure it is
1088 * alive. css && !memcg means that the groups should be
1089 * skipped and we should continue the tree walk.
1090 * last_visited css is safe to use because it is
1091 * protected by css_get and the tree walk is rcu safe.
1094 struct mem_cgroup
*mem
= mem_cgroup_from_css(next_css
);
1096 if (css_tryget(&mem
->css
))
1099 prev_css
= next_css
;
1107 static void mem_cgroup_iter_invalidate(struct mem_cgroup
*root
)
1110 * When a group in the hierarchy below root is destroyed, the
1111 * hierarchy iterator can no longer be trusted since it might
1112 * have pointed to the destroyed group. Invalidate it.
1114 atomic_inc(&root
->dead_count
);
1117 static struct mem_cgroup
*
1118 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter
*iter
,
1119 struct mem_cgroup
*root
,
1122 struct mem_cgroup
*position
= NULL
;
1124 * A cgroup destruction happens in two stages: offlining and
1125 * release. They are separated by a RCU grace period.
1127 * If the iterator is valid, we may still race with an
1128 * offlining. The RCU lock ensures the object won't be
1129 * released, tryget will fail if we lost the race.
1131 *sequence
= atomic_read(&root
->dead_count
);
1132 if (iter
->last_dead_count
== *sequence
) {
1134 position
= iter
->last_visited
;
1135 if (position
&& !css_tryget(&position
->css
))
1141 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter
*iter
,
1142 struct mem_cgroup
*last_visited
,
1143 struct mem_cgroup
*new_position
,
1147 css_put(&last_visited
->css
);
1149 * We store the sequence count from the time @last_visited was
1150 * loaded successfully instead of rereading it here so that we
1151 * don't lose destruction events in between. We could have
1152 * raced with the destruction of @new_position after all.
1154 iter
->last_visited
= new_position
;
1156 iter
->last_dead_count
= sequence
;
1160 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1161 * @root: hierarchy root
1162 * @prev: previously returned memcg, NULL on first invocation
1163 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1165 * Returns references to children of the hierarchy below @root, or
1166 * @root itself, or %NULL after a full round-trip.
1168 * Caller must pass the return value in @prev on subsequent
1169 * invocations for reference counting, or use mem_cgroup_iter_break()
1170 * to cancel a hierarchy walk before the round-trip is complete.
1172 * Reclaimers can specify a zone and a priority level in @reclaim to
1173 * divide up the memcgs in the hierarchy among all concurrent
1174 * reclaimers operating on the same zone and priority.
1176 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1177 struct mem_cgroup
*prev
,
1178 struct mem_cgroup_reclaim_cookie
*reclaim
)
1180 struct mem_cgroup
*memcg
= NULL
;
1181 struct mem_cgroup
*last_visited
= NULL
;
1183 if (mem_cgroup_disabled())
1187 root
= root_mem_cgroup
;
1189 if (prev
&& !reclaim
)
1190 last_visited
= prev
;
1192 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1200 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1201 int uninitialized_var(seq
);
1204 int nid
= zone_to_nid(reclaim
->zone
);
1205 int zid
= zone_idx(reclaim
->zone
);
1206 struct mem_cgroup_per_zone
*mz
;
1208 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1209 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1210 if (prev
&& reclaim
->generation
!= iter
->generation
) {
1211 iter
->last_visited
= NULL
;
1215 last_visited
= mem_cgroup_iter_load(iter
, root
, &seq
);
1218 memcg
= __mem_cgroup_iter_next(root
, last_visited
);
1221 mem_cgroup_iter_update(iter
, last_visited
, memcg
, seq
);
1225 else if (!prev
&& memcg
)
1226 reclaim
->generation
= iter
->generation
;
1235 if (prev
&& prev
!= root
)
1236 css_put(&prev
->css
);
1242 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1243 * @root: hierarchy root
1244 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1246 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1247 struct mem_cgroup
*prev
)
1250 root
= root_mem_cgroup
;
1251 if (prev
&& prev
!= root
)
1252 css_put(&prev
->css
);
1256 * Iteration constructs for visiting all cgroups (under a tree). If
1257 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1258 * be used for reference counting.
1260 #define for_each_mem_cgroup_tree(iter, root) \
1261 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1263 iter = mem_cgroup_iter(root, iter, NULL))
1265 #define for_each_mem_cgroup(iter) \
1266 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1268 iter = mem_cgroup_iter(NULL, iter, NULL))
1270 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1272 struct mem_cgroup
*memcg
;
1275 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1276 if (unlikely(!memcg
))
1281 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1284 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1292 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1295 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1296 * @zone: zone of the wanted lruvec
1297 * @memcg: memcg of the wanted lruvec
1299 * Returns the lru list vector holding pages for the given @zone and
1300 * @mem. This can be the global zone lruvec, if the memory controller
1303 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1304 struct mem_cgroup
*memcg
)
1306 struct mem_cgroup_per_zone
*mz
;
1307 struct lruvec
*lruvec
;
1309 if (mem_cgroup_disabled()) {
1310 lruvec
= &zone
->lruvec
;
1314 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1315 lruvec
= &mz
->lruvec
;
1318 * Since a node can be onlined after the mem_cgroup was created,
1319 * we have to be prepared to initialize lruvec->zone here;
1320 * and if offlined then reonlined, we need to reinitialize it.
1322 if (unlikely(lruvec
->zone
!= zone
))
1323 lruvec
->zone
= zone
;
1328 * Following LRU functions are allowed to be used without PCG_LOCK.
1329 * Operations are called by routine of global LRU independently from memcg.
1330 * What we have to take care of here is validness of pc->mem_cgroup.
1332 * Changes to pc->mem_cgroup happens when
1335 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1336 * It is added to LRU before charge.
1337 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1338 * When moving account, the page is not on LRU. It's isolated.
1342 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1344 * @zone: zone of the page
1346 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1348 struct mem_cgroup_per_zone
*mz
;
1349 struct mem_cgroup
*memcg
;
1350 struct page_cgroup
*pc
;
1351 struct lruvec
*lruvec
;
1353 if (mem_cgroup_disabled()) {
1354 lruvec
= &zone
->lruvec
;
1358 pc
= lookup_page_cgroup(page
);
1359 memcg
= pc
->mem_cgroup
;
1362 * Surreptitiously switch any uncharged offlist page to root:
1363 * an uncharged page off lru does nothing to secure
1364 * its former mem_cgroup from sudden removal.
1366 * Our caller holds lru_lock, and PageCgroupUsed is updated
1367 * under page_cgroup lock: between them, they make all uses
1368 * of pc->mem_cgroup safe.
1370 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1371 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1373 mz
= page_cgroup_zoneinfo(memcg
, page
);
1374 lruvec
= &mz
->lruvec
;
1377 * Since a node can be onlined after the mem_cgroup was created,
1378 * we have to be prepared to initialize lruvec->zone here;
1379 * and if offlined then reonlined, we need to reinitialize it.
1381 if (unlikely(lruvec
->zone
!= zone
))
1382 lruvec
->zone
= zone
;
1387 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1388 * @lruvec: mem_cgroup per zone lru vector
1389 * @lru: index of lru list the page is sitting on
1390 * @nr_pages: positive when adding or negative when removing
1392 * This function must be called when a page is added to or removed from an
1395 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1398 struct mem_cgroup_per_zone
*mz
;
1399 unsigned long *lru_size
;
1401 if (mem_cgroup_disabled())
1404 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1405 lru_size
= mz
->lru_size
+ lru
;
1406 *lru_size
+= nr_pages
;
1407 VM_BUG_ON((long)(*lru_size
) < 0);
1411 * Checks whether given mem is same or in the root_mem_cgroup's
1414 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1415 struct mem_cgroup
*memcg
)
1417 if (root_memcg
== memcg
)
1419 if (!root_memcg
->use_hierarchy
|| !memcg
)
1421 return css_is_ancestor(&memcg
->css
, &root_memcg
->css
);
1424 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1425 struct mem_cgroup
*memcg
)
1430 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1435 bool task_in_mem_cgroup(struct task_struct
*task
,
1436 const struct mem_cgroup
*memcg
)
1438 struct mem_cgroup
*curr
= NULL
;
1439 struct task_struct
*p
;
1442 p
= find_lock_task_mm(task
);
1444 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1448 * All threads may have already detached their mm's, but the oom
1449 * killer still needs to detect if they have already been oom
1450 * killed to prevent needlessly killing additional tasks.
1453 curr
= mem_cgroup_from_task(task
);
1455 css_get(&curr
->css
);
1461 * We should check use_hierarchy of "memcg" not "curr". Because checking
1462 * use_hierarchy of "curr" here make this function true if hierarchy is
1463 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1464 * hierarchy(even if use_hierarchy is disabled in "memcg").
1466 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1467 css_put(&curr
->css
);
1471 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1473 unsigned long inactive_ratio
;
1474 unsigned long inactive
;
1475 unsigned long active
;
1478 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1479 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1481 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1483 inactive_ratio
= int_sqrt(10 * gb
);
1487 return inactive
* inactive_ratio
< active
;
1490 #define mem_cgroup_from_res_counter(counter, member) \
1491 container_of(counter, struct mem_cgroup, member)
1494 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1495 * @memcg: the memory cgroup
1497 * Returns the maximum amount of memory @mem can be charged with, in
1500 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1502 unsigned long long margin
;
1504 margin
= res_counter_margin(&memcg
->res
);
1505 if (do_swap_account
)
1506 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1507 return margin
>> PAGE_SHIFT
;
1510 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1513 if (!css_parent(&memcg
->css
))
1514 return vm_swappiness
;
1516 return memcg
->swappiness
;
1520 * memcg->moving_account is used for checking possibility that some thread is
1521 * calling move_account(). When a thread on CPU-A starts moving pages under
1522 * a memcg, other threads should check memcg->moving_account under
1523 * rcu_read_lock(), like this:
1527 * memcg->moving_account+1 if (memcg->mocing_account)
1529 * synchronize_rcu() update something.
1534 /* for quick checking without looking up memcg */
1535 atomic_t memcg_moving __read_mostly
;
1537 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1539 atomic_inc(&memcg_moving
);
1540 atomic_inc(&memcg
->moving_account
);
1544 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1547 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1548 * We check NULL in callee rather than caller.
1551 atomic_dec(&memcg_moving
);
1552 atomic_dec(&memcg
->moving_account
);
1557 * 2 routines for checking "mem" is under move_account() or not.
1559 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1560 * is used for avoiding races in accounting. If true,
1561 * pc->mem_cgroup may be overwritten.
1563 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1564 * under hierarchy of moving cgroups. This is for
1565 * waiting at hith-memory prressure caused by "move".
1568 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1570 VM_BUG_ON(!rcu_read_lock_held());
1571 return atomic_read(&memcg
->moving_account
) > 0;
1574 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1576 struct mem_cgroup
*from
;
1577 struct mem_cgroup
*to
;
1580 * Unlike task_move routines, we access mc.to, mc.from not under
1581 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1583 spin_lock(&mc
.lock
);
1589 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1590 || mem_cgroup_same_or_subtree(memcg
, to
);
1592 spin_unlock(&mc
.lock
);
1596 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1598 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1599 if (mem_cgroup_under_move(memcg
)) {
1601 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1602 /* moving charge context might have finished. */
1605 finish_wait(&mc
.waitq
, &wait
);
1613 * Take this lock when
1614 * - a code tries to modify page's memcg while it's USED.
1615 * - a code tries to modify page state accounting in a memcg.
1616 * see mem_cgroup_stolen(), too.
1618 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1619 unsigned long *flags
)
1621 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1624 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1625 unsigned long *flags
)
1627 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1630 #define K(x) ((x) << (PAGE_SHIFT-10))
1632 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1633 * @memcg: The memory cgroup that went over limit
1634 * @p: Task that is going to be killed
1636 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1639 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1641 struct cgroup
*task_cgrp
;
1642 struct cgroup
*mem_cgrp
;
1644 * Need a buffer in BSS, can't rely on allocations. The code relies
1645 * on the assumption that OOM is serialized for memory controller.
1646 * If this assumption is broken, revisit this code.
1648 static char memcg_name
[PATH_MAX
];
1650 struct mem_cgroup
*iter
;
1658 mem_cgrp
= memcg
->css
.cgroup
;
1659 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1661 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1664 * Unfortunately, we are unable to convert to a useful name
1665 * But we'll still print out the usage information
1672 pr_info("Task in %s killed", memcg_name
);
1675 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1683 * Continues from above, so we don't need an KERN_ level
1685 pr_cont(" as a result of limit of %s\n", memcg_name
);
1688 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1689 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1690 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1691 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1692 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1693 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1694 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1695 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1696 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1697 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1698 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1699 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1701 for_each_mem_cgroup_tree(iter
, memcg
) {
1702 pr_info("Memory cgroup stats");
1705 ret
= cgroup_path(iter
->css
.cgroup
, memcg_name
, PATH_MAX
);
1707 pr_cont(" for %s", memcg_name
);
1711 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1712 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1714 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1715 K(mem_cgroup_read_stat(iter
, i
)));
1718 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1719 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1720 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1727 * This function returns the number of memcg under hierarchy tree. Returns
1728 * 1(self count) if no children.
1730 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1733 struct mem_cgroup
*iter
;
1735 for_each_mem_cgroup_tree(iter
, memcg
)
1741 * Return the memory (and swap, if configured) limit for a memcg.
1743 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1747 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1750 * Do not consider swap space if we cannot swap due to swappiness
1752 if (mem_cgroup_swappiness(memcg
)) {
1755 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1756 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1759 * If memsw is finite and limits the amount of swap space
1760 * available to this memcg, return that limit.
1762 limit
= min(limit
, memsw
);
1768 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1771 struct mem_cgroup
*iter
;
1772 unsigned long chosen_points
= 0;
1773 unsigned long totalpages
;
1774 unsigned int points
= 0;
1775 struct task_struct
*chosen
= NULL
;
1778 * If current has a pending SIGKILL or is exiting, then automatically
1779 * select it. The goal is to allow it to allocate so that it may
1780 * quickly exit and free its memory.
1782 if (fatal_signal_pending(current
) || current
->flags
& PF_EXITING
) {
1783 set_thread_flag(TIF_MEMDIE
);
1787 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1788 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1789 for_each_mem_cgroup_tree(iter
, memcg
) {
1790 struct css_task_iter it
;
1791 struct task_struct
*task
;
1793 css_task_iter_start(&iter
->css
, &it
);
1794 while ((task
= css_task_iter_next(&it
))) {
1795 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1797 case OOM_SCAN_SELECT
:
1799 put_task_struct(chosen
);
1801 chosen_points
= ULONG_MAX
;
1802 get_task_struct(chosen
);
1804 case OOM_SCAN_CONTINUE
:
1806 case OOM_SCAN_ABORT
:
1807 css_task_iter_end(&it
);
1808 mem_cgroup_iter_break(memcg
, iter
);
1810 put_task_struct(chosen
);
1815 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1816 if (points
> chosen_points
) {
1818 put_task_struct(chosen
);
1820 chosen_points
= points
;
1821 get_task_struct(chosen
);
1824 css_task_iter_end(&it
);
1829 points
= chosen_points
* 1000 / totalpages
;
1830 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1831 NULL
, "Memory cgroup out of memory");
1834 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1836 unsigned long flags
)
1838 unsigned long total
= 0;
1839 bool noswap
= false;
1842 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1844 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1847 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1849 drain_all_stock_async(memcg
);
1850 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1852 * Allow limit shrinkers, which are triggered directly
1853 * by userspace, to catch signals and stop reclaim
1854 * after minimal progress, regardless of the margin.
1856 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1858 if (mem_cgroup_margin(memcg
))
1861 * If nothing was reclaimed after two attempts, there
1862 * may be no reclaimable pages in this hierarchy.
1871 * test_mem_cgroup_node_reclaimable
1872 * @memcg: the target memcg
1873 * @nid: the node ID to be checked.
1874 * @noswap : specify true here if the user wants flle only information.
1876 * This function returns whether the specified memcg contains any
1877 * reclaimable pages on a node. Returns true if there are any reclaimable
1878 * pages in the node.
1880 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1881 int nid
, bool noswap
)
1883 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1885 if (noswap
|| !total_swap_pages
)
1887 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1892 #if MAX_NUMNODES > 1
1895 * Always updating the nodemask is not very good - even if we have an empty
1896 * list or the wrong list here, we can start from some node and traverse all
1897 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1900 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1904 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1905 * pagein/pageout changes since the last update.
1907 if (!atomic_read(&memcg
->numainfo_events
))
1909 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1912 /* make a nodemask where this memcg uses memory from */
1913 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1915 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1917 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1918 node_clear(nid
, memcg
->scan_nodes
);
1921 atomic_set(&memcg
->numainfo_events
, 0);
1922 atomic_set(&memcg
->numainfo_updating
, 0);
1926 * Selecting a node where we start reclaim from. Because what we need is just
1927 * reducing usage counter, start from anywhere is O,K. Considering
1928 * memory reclaim from current node, there are pros. and cons.
1930 * Freeing memory from current node means freeing memory from a node which
1931 * we'll use or we've used. So, it may make LRU bad. And if several threads
1932 * hit limits, it will see a contention on a node. But freeing from remote
1933 * node means more costs for memory reclaim because of memory latency.
1935 * Now, we use round-robin. Better algorithm is welcomed.
1937 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1941 mem_cgroup_may_update_nodemask(memcg
);
1942 node
= memcg
->last_scanned_node
;
1944 node
= next_node(node
, memcg
->scan_nodes
);
1945 if (node
== MAX_NUMNODES
)
1946 node
= first_node(memcg
->scan_nodes
);
1948 * We call this when we hit limit, not when pages are added to LRU.
1949 * No LRU may hold pages because all pages are UNEVICTABLE or
1950 * memcg is too small and all pages are not on LRU. In that case,
1951 * we use curret node.
1953 if (unlikely(node
== MAX_NUMNODES
))
1954 node
= numa_node_id();
1956 memcg
->last_scanned_node
= node
;
1961 * Check all nodes whether it contains reclaimable pages or not.
1962 * For quick scan, we make use of scan_nodes. This will allow us to skip
1963 * unused nodes. But scan_nodes is lazily updated and may not cotain
1964 * enough new information. We need to do double check.
1966 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1971 * quick check...making use of scan_node.
1972 * We can skip unused nodes.
1974 if (!nodes_empty(memcg
->scan_nodes
)) {
1975 for (nid
= first_node(memcg
->scan_nodes
);
1977 nid
= next_node(nid
, memcg
->scan_nodes
)) {
1979 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1984 * Check rest of nodes.
1986 for_each_node_state(nid
, N_MEMORY
) {
1987 if (node_isset(nid
, memcg
->scan_nodes
))
1989 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1996 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
2001 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
2003 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
2008 * A group is eligible for the soft limit reclaim if it is
2009 * a) is over its soft limit
2010 * b) any parent up the hierarchy is over its soft limit
2012 bool mem_cgroup_soft_reclaim_eligible(struct mem_cgroup
*memcg
)
2014 struct mem_cgroup
*parent
= memcg
;
2016 if (res_counter_soft_limit_excess(&memcg
->res
))
2020 * If any parent up the hierarchy is over its soft limit then we
2021 * have to obey and reclaim from this group as well.
2023 while((parent
= parent_mem_cgroup(parent
))) {
2024 if (res_counter_soft_limit_excess(&parent
->res
))
2032 * Check OOM-Killer is already running under our hierarchy.
2033 * If someone is running, return false.
2034 * Has to be called with memcg_oom_lock
2036 static bool mem_cgroup_oom_lock(struct mem_cgroup
*memcg
)
2038 struct mem_cgroup
*iter
, *failed
= NULL
;
2040 for_each_mem_cgroup_tree(iter
, memcg
) {
2041 if (iter
->oom_lock
) {
2043 * this subtree of our hierarchy is already locked
2044 * so we cannot give a lock.
2047 mem_cgroup_iter_break(memcg
, iter
);
2050 iter
->oom_lock
= true;
2057 * OK, we failed to lock the whole subtree so we have to clean up
2058 * what we set up to the failing subtree
2060 for_each_mem_cgroup_tree(iter
, memcg
) {
2061 if (iter
== failed
) {
2062 mem_cgroup_iter_break(memcg
, iter
);
2065 iter
->oom_lock
= false;
2071 * Has to be called with memcg_oom_lock
2073 static int mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2075 struct mem_cgroup
*iter
;
2077 for_each_mem_cgroup_tree(iter
, memcg
)
2078 iter
->oom_lock
= false;
2082 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2084 struct mem_cgroup
*iter
;
2086 for_each_mem_cgroup_tree(iter
, memcg
)
2087 atomic_inc(&iter
->under_oom
);
2090 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2092 struct mem_cgroup
*iter
;
2095 * When a new child is created while the hierarchy is under oom,
2096 * mem_cgroup_oom_lock() may not be called. We have to use
2097 * atomic_add_unless() here.
2099 for_each_mem_cgroup_tree(iter
, memcg
)
2100 atomic_add_unless(&iter
->under_oom
, -1, 0);
2103 static DEFINE_SPINLOCK(memcg_oom_lock
);
2104 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2106 struct oom_wait_info
{
2107 struct mem_cgroup
*memcg
;
2111 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2112 unsigned mode
, int sync
, void *arg
)
2114 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2115 struct mem_cgroup
*oom_wait_memcg
;
2116 struct oom_wait_info
*oom_wait_info
;
2118 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2119 oom_wait_memcg
= oom_wait_info
->memcg
;
2122 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2123 * Then we can use css_is_ancestor without taking care of RCU.
2125 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2126 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2128 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2131 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2133 /* for filtering, pass "memcg" as argument. */
2134 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2137 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2139 if (memcg
&& atomic_read(&memcg
->under_oom
))
2140 memcg_wakeup_oom(memcg
);
2144 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
2146 static bool mem_cgroup_handle_oom(struct mem_cgroup
*memcg
, gfp_t mask
,
2149 struct oom_wait_info owait
;
2150 bool locked
, need_to_kill
;
2152 owait
.memcg
= memcg
;
2153 owait
.wait
.flags
= 0;
2154 owait
.wait
.func
= memcg_oom_wake_function
;
2155 owait
.wait
.private = current
;
2156 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2157 need_to_kill
= true;
2158 mem_cgroup_mark_under_oom(memcg
);
2160 /* At first, try to OOM lock hierarchy under memcg.*/
2161 spin_lock(&memcg_oom_lock
);
2162 locked
= mem_cgroup_oom_lock(memcg
);
2164 * Even if signal_pending(), we can't quit charge() loop without
2165 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
2166 * under OOM is always welcomed, use TASK_KILLABLE here.
2168 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2169 if (!locked
|| memcg
->oom_kill_disable
)
2170 need_to_kill
= false;
2172 mem_cgroup_oom_notify(memcg
);
2173 spin_unlock(&memcg_oom_lock
);
2176 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2177 mem_cgroup_out_of_memory(memcg
, mask
, order
);
2180 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2182 spin_lock(&memcg_oom_lock
);
2184 mem_cgroup_oom_unlock(memcg
);
2185 memcg_wakeup_oom(memcg
);
2186 spin_unlock(&memcg_oom_lock
);
2188 mem_cgroup_unmark_under_oom(memcg
);
2190 if (test_thread_flag(TIF_MEMDIE
) || fatal_signal_pending(current
))
2192 /* Give chance to dying process */
2193 schedule_timeout_uninterruptible(1);
2198 * Currently used to update mapped file statistics, but the routine can be
2199 * generalized to update other statistics as well.
2201 * Notes: Race condition
2203 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2204 * it tends to be costly. But considering some conditions, we doesn't need
2205 * to do so _always_.
2207 * Considering "charge", lock_page_cgroup() is not required because all
2208 * file-stat operations happen after a page is attached to radix-tree. There
2209 * are no race with "charge".
2211 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2212 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2213 * if there are race with "uncharge". Statistics itself is properly handled
2216 * Considering "move", this is an only case we see a race. To make the race
2217 * small, we check mm->moving_account and detect there are possibility of race
2218 * If there is, we take a lock.
2221 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2222 bool *locked
, unsigned long *flags
)
2224 struct mem_cgroup
*memcg
;
2225 struct page_cgroup
*pc
;
2227 pc
= lookup_page_cgroup(page
);
2229 memcg
= pc
->mem_cgroup
;
2230 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2233 * If this memory cgroup is not under account moving, we don't
2234 * need to take move_lock_mem_cgroup(). Because we already hold
2235 * rcu_read_lock(), any calls to move_account will be delayed until
2236 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2238 if (!mem_cgroup_stolen(memcg
))
2241 move_lock_mem_cgroup(memcg
, flags
);
2242 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2243 move_unlock_mem_cgroup(memcg
, flags
);
2249 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2251 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2254 * It's guaranteed that pc->mem_cgroup never changes while
2255 * lock is held because a routine modifies pc->mem_cgroup
2256 * should take move_lock_mem_cgroup().
2258 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2261 void mem_cgroup_update_page_stat(struct page
*page
,
2262 enum mem_cgroup_page_stat_item idx
, int val
)
2264 struct mem_cgroup
*memcg
;
2265 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2266 unsigned long uninitialized_var(flags
);
2268 if (mem_cgroup_disabled())
2271 memcg
= pc
->mem_cgroup
;
2272 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2276 case MEMCG_NR_FILE_MAPPED
:
2277 idx
= MEM_CGROUP_STAT_FILE_MAPPED
;
2283 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2287 * size of first charge trial. "32" comes from vmscan.c's magic value.
2288 * TODO: maybe necessary to use big numbers in big irons.
2290 #define CHARGE_BATCH 32U
2291 struct memcg_stock_pcp
{
2292 struct mem_cgroup
*cached
; /* this never be root cgroup */
2293 unsigned int nr_pages
;
2294 struct work_struct work
;
2295 unsigned long flags
;
2296 #define FLUSHING_CACHED_CHARGE 0
2298 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2299 static DEFINE_MUTEX(percpu_charge_mutex
);
2302 * consume_stock: Try to consume stocked charge on this cpu.
2303 * @memcg: memcg to consume from.
2304 * @nr_pages: how many pages to charge.
2306 * The charges will only happen if @memcg matches the current cpu's memcg
2307 * stock, and at least @nr_pages are available in that stock. Failure to
2308 * service an allocation will refill the stock.
2310 * returns true if successful, false otherwise.
2312 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2314 struct memcg_stock_pcp
*stock
;
2317 if (nr_pages
> CHARGE_BATCH
)
2320 stock
= &get_cpu_var(memcg_stock
);
2321 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2322 stock
->nr_pages
-= nr_pages
;
2323 else /* need to call res_counter_charge */
2325 put_cpu_var(memcg_stock
);
2330 * Returns stocks cached in percpu to res_counter and reset cached information.
2332 static void drain_stock(struct memcg_stock_pcp
*stock
)
2334 struct mem_cgroup
*old
= stock
->cached
;
2336 if (stock
->nr_pages
) {
2337 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2339 res_counter_uncharge(&old
->res
, bytes
);
2340 if (do_swap_account
)
2341 res_counter_uncharge(&old
->memsw
, bytes
);
2342 stock
->nr_pages
= 0;
2344 stock
->cached
= NULL
;
2348 * This must be called under preempt disabled or must be called by
2349 * a thread which is pinned to local cpu.
2351 static void drain_local_stock(struct work_struct
*dummy
)
2353 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2355 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2358 static void __init
memcg_stock_init(void)
2362 for_each_possible_cpu(cpu
) {
2363 struct memcg_stock_pcp
*stock
=
2364 &per_cpu(memcg_stock
, cpu
);
2365 INIT_WORK(&stock
->work
, drain_local_stock
);
2370 * Cache charges(val) which is from res_counter, to local per_cpu area.
2371 * This will be consumed by consume_stock() function, later.
2373 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2375 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2377 if (stock
->cached
!= memcg
) { /* reset if necessary */
2379 stock
->cached
= memcg
;
2381 stock
->nr_pages
+= nr_pages
;
2382 put_cpu_var(memcg_stock
);
2386 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2387 * of the hierarchy under it. sync flag says whether we should block
2388 * until the work is done.
2390 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2394 /* Notify other cpus that system-wide "drain" is running */
2397 for_each_online_cpu(cpu
) {
2398 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2399 struct mem_cgroup
*memcg
;
2401 memcg
= stock
->cached
;
2402 if (!memcg
|| !stock
->nr_pages
)
2404 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2406 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2408 drain_local_stock(&stock
->work
);
2410 schedule_work_on(cpu
, &stock
->work
);
2418 for_each_online_cpu(cpu
) {
2419 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2420 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2421 flush_work(&stock
->work
);
2428 * Tries to drain stocked charges in other cpus. This function is asynchronous
2429 * and just put a work per cpu for draining localy on each cpu. Caller can
2430 * expects some charges will be back to res_counter later but cannot wait for
2433 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2436 * If someone calls draining, avoid adding more kworker runs.
2438 if (!mutex_trylock(&percpu_charge_mutex
))
2440 drain_all_stock(root_memcg
, false);
2441 mutex_unlock(&percpu_charge_mutex
);
2444 /* This is a synchronous drain interface. */
2445 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2447 /* called when force_empty is called */
2448 mutex_lock(&percpu_charge_mutex
);
2449 drain_all_stock(root_memcg
, true);
2450 mutex_unlock(&percpu_charge_mutex
);
2454 * This function drains percpu counter value from DEAD cpu and
2455 * move it to local cpu. Note that this function can be preempted.
2457 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2461 spin_lock(&memcg
->pcp_counter_lock
);
2462 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2463 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2465 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2466 memcg
->nocpu_base
.count
[i
] += x
;
2468 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2469 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2471 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2472 memcg
->nocpu_base
.events
[i
] += x
;
2474 spin_unlock(&memcg
->pcp_counter_lock
);
2477 static int memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2478 unsigned long action
,
2481 int cpu
= (unsigned long)hcpu
;
2482 struct memcg_stock_pcp
*stock
;
2483 struct mem_cgroup
*iter
;
2485 if (action
== CPU_ONLINE
)
2488 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2491 for_each_mem_cgroup(iter
)
2492 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2494 stock
= &per_cpu(memcg_stock
, cpu
);
2500 /* See __mem_cgroup_try_charge() for details */
2502 CHARGE_OK
, /* success */
2503 CHARGE_RETRY
, /* need to retry but retry is not bad */
2504 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2505 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2506 CHARGE_OOM_DIE
, /* the current is killed because of OOM */
2509 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2510 unsigned int nr_pages
, unsigned int min_pages
,
2513 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2514 struct mem_cgroup
*mem_over_limit
;
2515 struct res_counter
*fail_res
;
2516 unsigned long flags
= 0;
2519 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2522 if (!do_swap_account
)
2524 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2528 res_counter_uncharge(&memcg
->res
, csize
);
2529 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2530 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2532 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2534 * Never reclaim on behalf of optional batching, retry with a
2535 * single page instead.
2537 if (nr_pages
> min_pages
)
2538 return CHARGE_RETRY
;
2540 if (!(gfp_mask
& __GFP_WAIT
))
2541 return CHARGE_WOULDBLOCK
;
2543 if (gfp_mask
& __GFP_NORETRY
)
2544 return CHARGE_NOMEM
;
2546 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2547 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2548 return CHARGE_RETRY
;
2550 * Even though the limit is exceeded at this point, reclaim
2551 * may have been able to free some pages. Retry the charge
2552 * before killing the task.
2554 * Only for regular pages, though: huge pages are rather
2555 * unlikely to succeed so close to the limit, and we fall back
2556 * to regular pages anyway in case of failure.
2558 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2559 return CHARGE_RETRY
;
2562 * At task move, charge accounts can be doubly counted. So, it's
2563 * better to wait until the end of task_move if something is going on.
2565 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2566 return CHARGE_RETRY
;
2568 /* If we don't need to call oom-killer at el, return immediately */
2570 return CHARGE_NOMEM
;
2572 if (!mem_cgroup_handle_oom(mem_over_limit
, gfp_mask
, get_order(csize
)))
2573 return CHARGE_OOM_DIE
;
2575 return CHARGE_RETRY
;
2579 * __mem_cgroup_try_charge() does
2580 * 1. detect memcg to be charged against from passed *mm and *ptr,
2581 * 2. update res_counter
2582 * 3. call memory reclaim if necessary.
2584 * In some special case, if the task is fatal, fatal_signal_pending() or
2585 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2586 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2587 * as possible without any hazards. 2: all pages should have a valid
2588 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2589 * pointer, that is treated as a charge to root_mem_cgroup.
2591 * So __mem_cgroup_try_charge() will return
2592 * 0 ... on success, filling *ptr with a valid memcg pointer.
2593 * -ENOMEM ... charge failure because of resource limits.
2594 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2596 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2597 * the oom-killer can be invoked.
2599 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2601 unsigned int nr_pages
,
2602 struct mem_cgroup
**ptr
,
2605 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2606 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2607 struct mem_cgroup
*memcg
= NULL
;
2611 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2612 * in system level. So, allow to go ahead dying process in addition to
2615 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2616 || fatal_signal_pending(current
)))
2620 * We always charge the cgroup the mm_struct belongs to.
2621 * The mm_struct's mem_cgroup changes on task migration if the
2622 * thread group leader migrates. It's possible that mm is not
2623 * set, if so charge the root memcg (happens for pagecache usage).
2626 *ptr
= root_mem_cgroup
;
2628 if (*ptr
) { /* css should be a valid one */
2630 if (mem_cgroup_is_root(memcg
))
2632 if (consume_stock(memcg
, nr_pages
))
2634 css_get(&memcg
->css
);
2636 struct task_struct
*p
;
2639 p
= rcu_dereference(mm
->owner
);
2641 * Because we don't have task_lock(), "p" can exit.
2642 * In that case, "memcg" can point to root or p can be NULL with
2643 * race with swapoff. Then, we have small risk of mis-accouning.
2644 * But such kind of mis-account by race always happens because
2645 * we don't have cgroup_mutex(). It's overkill and we allo that
2647 * (*) swapoff at el will charge against mm-struct not against
2648 * task-struct. So, mm->owner can be NULL.
2650 memcg
= mem_cgroup_from_task(p
);
2652 memcg
= root_mem_cgroup
;
2653 if (mem_cgroup_is_root(memcg
)) {
2657 if (consume_stock(memcg
, nr_pages
)) {
2659 * It seems dagerous to access memcg without css_get().
2660 * But considering how consume_stok works, it's not
2661 * necessary. If consume_stock success, some charges
2662 * from this memcg are cached on this cpu. So, we
2663 * don't need to call css_get()/css_tryget() before
2664 * calling consume_stock().
2669 /* after here, we may be blocked. we need to get refcnt */
2670 if (!css_tryget(&memcg
->css
)) {
2680 /* If killed, bypass charge */
2681 if (fatal_signal_pending(current
)) {
2682 css_put(&memcg
->css
);
2687 if (oom
&& !nr_oom_retries
) {
2689 nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2692 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
, nr_pages
,
2697 case CHARGE_RETRY
: /* not in OOM situation but retry */
2699 css_put(&memcg
->css
);
2702 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2703 css_put(&memcg
->css
);
2705 case CHARGE_NOMEM
: /* OOM routine works */
2707 css_put(&memcg
->css
);
2710 /* If oom, we never return -ENOMEM */
2713 case CHARGE_OOM_DIE
: /* Killed by OOM Killer */
2714 css_put(&memcg
->css
);
2717 } while (ret
!= CHARGE_OK
);
2719 if (batch
> nr_pages
)
2720 refill_stock(memcg
, batch
- nr_pages
);
2721 css_put(&memcg
->css
);
2729 *ptr
= root_mem_cgroup
;
2734 * Somemtimes we have to undo a charge we got by try_charge().
2735 * This function is for that and do uncharge, put css's refcnt.
2736 * gotten by try_charge().
2738 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2739 unsigned int nr_pages
)
2741 if (!mem_cgroup_is_root(memcg
)) {
2742 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2744 res_counter_uncharge(&memcg
->res
, bytes
);
2745 if (do_swap_account
)
2746 res_counter_uncharge(&memcg
->memsw
, bytes
);
2751 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2752 * This is useful when moving usage to parent cgroup.
2754 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2755 unsigned int nr_pages
)
2757 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2759 if (mem_cgroup_is_root(memcg
))
2762 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2763 if (do_swap_account
)
2764 res_counter_uncharge_until(&memcg
->memsw
,
2765 memcg
->memsw
.parent
, bytes
);
2769 * A helper function to get mem_cgroup from ID. must be called under
2770 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2771 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2772 * called against removed memcg.)
2774 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2776 struct cgroup_subsys_state
*css
;
2778 /* ID 0 is unused ID */
2781 css
= css_lookup(&mem_cgroup_subsys
, id
);
2784 return mem_cgroup_from_css(css
);
2787 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2789 struct mem_cgroup
*memcg
= NULL
;
2790 struct page_cgroup
*pc
;
2794 VM_BUG_ON(!PageLocked(page
));
2796 pc
= lookup_page_cgroup(page
);
2797 lock_page_cgroup(pc
);
2798 if (PageCgroupUsed(pc
)) {
2799 memcg
= pc
->mem_cgroup
;
2800 if (memcg
&& !css_tryget(&memcg
->css
))
2802 } else if (PageSwapCache(page
)) {
2803 ent
.val
= page_private(page
);
2804 id
= lookup_swap_cgroup_id(ent
);
2806 memcg
= mem_cgroup_lookup(id
);
2807 if (memcg
&& !css_tryget(&memcg
->css
))
2811 unlock_page_cgroup(pc
);
2815 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2817 unsigned int nr_pages
,
2818 enum charge_type ctype
,
2821 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2822 struct zone
*uninitialized_var(zone
);
2823 struct lruvec
*lruvec
;
2824 bool was_on_lru
= false;
2827 lock_page_cgroup(pc
);
2828 VM_BUG_ON(PageCgroupUsed(pc
));
2830 * we don't need page_cgroup_lock about tail pages, becase they are not
2831 * accessed by any other context at this point.
2835 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2836 * may already be on some other mem_cgroup's LRU. Take care of it.
2839 zone
= page_zone(page
);
2840 spin_lock_irq(&zone
->lru_lock
);
2841 if (PageLRU(page
)) {
2842 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2844 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2849 pc
->mem_cgroup
= memcg
;
2851 * We access a page_cgroup asynchronously without lock_page_cgroup().
2852 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2853 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2854 * before USED bit, we need memory barrier here.
2855 * See mem_cgroup_add_lru_list(), etc.
2858 SetPageCgroupUsed(pc
);
2862 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2863 VM_BUG_ON(PageLRU(page
));
2865 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2867 spin_unlock_irq(&zone
->lru_lock
);
2870 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2875 mem_cgroup_charge_statistics(memcg
, page
, anon
, nr_pages
);
2876 unlock_page_cgroup(pc
);
2879 * "charge_statistics" updated event counter. Then, check it.
2880 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2881 * if they exceeds softlimit.
2883 memcg_check_events(memcg
, page
);
2886 static DEFINE_MUTEX(set_limit_mutex
);
2888 #ifdef CONFIG_MEMCG_KMEM
2889 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2891 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
2892 (memcg
->kmem_account_flags
& KMEM_ACCOUNTED_MASK
);
2896 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2897 * in the memcg_cache_params struct.
2899 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2901 struct kmem_cache
*cachep
;
2903 VM_BUG_ON(p
->is_root_cache
);
2904 cachep
= p
->root_cache
;
2905 return cachep
->memcg_params
->memcg_caches
[memcg_cache_id(p
->memcg
)];
2908 #ifdef CONFIG_SLABINFO
2909 static int mem_cgroup_slabinfo_read(struct cgroup_subsys_state
*css
,
2910 struct cftype
*cft
, struct seq_file
*m
)
2912 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2913 struct memcg_cache_params
*params
;
2915 if (!memcg_can_account_kmem(memcg
))
2918 print_slabinfo_header(m
);
2920 mutex_lock(&memcg
->slab_caches_mutex
);
2921 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
2922 cache_show(memcg_params_to_cache(params
), m
);
2923 mutex_unlock(&memcg
->slab_caches_mutex
);
2929 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
2931 struct res_counter
*fail_res
;
2932 struct mem_cgroup
*_memcg
;
2936 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
2941 * Conditions under which we can wait for the oom_killer. Those are
2942 * the same conditions tested by the core page allocator
2944 may_oom
= (gfp
& __GFP_FS
) && !(gfp
& __GFP_NORETRY
);
2947 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
2950 if (ret
== -EINTR
) {
2952 * __mem_cgroup_try_charge() chosed to bypass to root due to
2953 * OOM kill or fatal signal. Since our only options are to
2954 * either fail the allocation or charge it to this cgroup, do
2955 * it as a temporary condition. But we can't fail. From a
2956 * kmem/slab perspective, the cache has already been selected,
2957 * by mem_cgroup_kmem_get_cache(), so it is too late to change
2960 * This condition will only trigger if the task entered
2961 * memcg_charge_kmem in a sane state, but was OOM-killed during
2962 * __mem_cgroup_try_charge() above. Tasks that were already
2963 * dying when the allocation triggers should have been already
2964 * directed to the root cgroup in memcontrol.h
2966 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
2967 if (do_swap_account
)
2968 res_counter_charge_nofail(&memcg
->memsw
, size
,
2972 res_counter_uncharge(&memcg
->kmem
, size
);
2977 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
2979 res_counter_uncharge(&memcg
->res
, size
);
2980 if (do_swap_account
)
2981 res_counter_uncharge(&memcg
->memsw
, size
);
2984 if (res_counter_uncharge(&memcg
->kmem
, size
))
2988 * Releases a reference taken in kmem_cgroup_css_offline in case
2989 * this last uncharge is racing with the offlining code or it is
2990 * outliving the memcg existence.
2992 * The memory barrier imposed by test&clear is paired with the
2993 * explicit one in memcg_kmem_mark_dead().
2995 if (memcg_kmem_test_and_clear_dead(memcg
))
2996 css_put(&memcg
->css
);
2999 void memcg_cache_list_add(struct mem_cgroup
*memcg
, struct kmem_cache
*cachep
)
3004 mutex_lock(&memcg
->slab_caches_mutex
);
3005 list_add(&cachep
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
3006 mutex_unlock(&memcg
->slab_caches_mutex
);
3010 * helper for acessing a memcg's index. It will be used as an index in the
3011 * child cache array in kmem_cache, and also to derive its name. This function
3012 * will return -1 when this is not a kmem-limited memcg.
3014 int memcg_cache_id(struct mem_cgroup
*memcg
)
3016 return memcg
? memcg
->kmemcg_id
: -1;
3020 * This ends up being protected by the set_limit mutex, during normal
3021 * operation, because that is its main call site.
3023 * But when we create a new cache, we can call this as well if its parent
3024 * is kmem-limited. That will have to hold set_limit_mutex as well.
3026 int memcg_update_cache_sizes(struct mem_cgroup
*memcg
)
3030 num
= ida_simple_get(&kmem_limited_groups
,
3031 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
3035 * After this point, kmem_accounted (that we test atomically in
3036 * the beginning of this conditional), is no longer 0. This
3037 * guarantees only one process will set the following boolean
3038 * to true. We don't need test_and_set because we're protected
3039 * by the set_limit_mutex anyway.
3041 memcg_kmem_set_activated(memcg
);
3043 ret
= memcg_update_all_caches(num
+1);
3045 ida_simple_remove(&kmem_limited_groups
, num
);
3046 memcg_kmem_clear_activated(memcg
);
3050 memcg
->kmemcg_id
= num
;
3051 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
3052 mutex_init(&memcg
->slab_caches_mutex
);
3056 static size_t memcg_caches_array_size(int num_groups
)
3059 if (num_groups
<= 0)
3062 size
= 2 * num_groups
;
3063 if (size
< MEMCG_CACHES_MIN_SIZE
)
3064 size
= MEMCG_CACHES_MIN_SIZE
;
3065 else if (size
> MEMCG_CACHES_MAX_SIZE
)
3066 size
= MEMCG_CACHES_MAX_SIZE
;
3072 * We should update the current array size iff all caches updates succeed. This
3073 * can only be done from the slab side. The slab mutex needs to be held when
3076 void memcg_update_array_size(int num
)
3078 if (num
> memcg_limited_groups_array_size
)
3079 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3082 static void kmem_cache_destroy_work_func(struct work_struct
*w
);
3084 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3086 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3088 VM_BUG_ON(s
->memcg_params
&& !s
->memcg_params
->is_root_cache
);
3090 if (num_groups
> memcg_limited_groups_array_size
) {
3092 ssize_t size
= memcg_caches_array_size(num_groups
);
3094 size
*= sizeof(void *);
3095 size
+= offsetof(struct memcg_cache_params
, memcg_caches
);
3097 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3098 if (!s
->memcg_params
) {
3099 s
->memcg_params
= cur_params
;
3103 s
->memcg_params
->is_root_cache
= true;
3106 * There is the chance it will be bigger than
3107 * memcg_limited_groups_array_size, if we failed an allocation
3108 * in a cache, in which case all caches updated before it, will
3109 * have a bigger array.
3111 * But if that is the case, the data after
3112 * memcg_limited_groups_array_size is certainly unused
3114 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3115 if (!cur_params
->memcg_caches
[i
])
3117 s
->memcg_params
->memcg_caches
[i
] =
3118 cur_params
->memcg_caches
[i
];
3122 * Ideally, we would wait until all caches succeed, and only
3123 * then free the old one. But this is not worth the extra
3124 * pointer per-cache we'd have to have for this.
3126 * It is not a big deal if some caches are left with a size
3127 * bigger than the others. And all updates will reset this
3135 int memcg_register_cache(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3136 struct kmem_cache
*root_cache
)
3140 if (!memcg_kmem_enabled())
3144 size
= offsetof(struct memcg_cache_params
, memcg_caches
);
3145 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3147 size
= sizeof(struct memcg_cache_params
);
3149 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3150 if (!s
->memcg_params
)
3154 s
->memcg_params
->memcg
= memcg
;
3155 s
->memcg_params
->root_cache
= root_cache
;
3156 INIT_WORK(&s
->memcg_params
->destroy
,
3157 kmem_cache_destroy_work_func
);
3159 s
->memcg_params
->is_root_cache
= true;
3164 void memcg_release_cache(struct kmem_cache
*s
)
3166 struct kmem_cache
*root
;
3167 struct mem_cgroup
*memcg
;
3171 * This happens, for instance, when a root cache goes away before we
3174 if (!s
->memcg_params
)
3177 if (s
->memcg_params
->is_root_cache
)
3180 memcg
= s
->memcg_params
->memcg
;
3181 id
= memcg_cache_id(memcg
);
3183 root
= s
->memcg_params
->root_cache
;
3184 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3186 mutex_lock(&memcg
->slab_caches_mutex
);
3187 list_del(&s
->memcg_params
->list
);
3188 mutex_unlock(&memcg
->slab_caches_mutex
);
3190 css_put(&memcg
->css
);
3192 kfree(s
->memcg_params
);
3196 * During the creation a new cache, we need to disable our accounting mechanism
3197 * altogether. This is true even if we are not creating, but rather just
3198 * enqueing new caches to be created.
3200 * This is because that process will trigger allocations; some visible, like
3201 * explicit kmallocs to auxiliary data structures, name strings and internal
3202 * cache structures; some well concealed, like INIT_WORK() that can allocate
3203 * objects during debug.
3205 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3206 * to it. This may not be a bounded recursion: since the first cache creation
3207 * failed to complete (waiting on the allocation), we'll just try to create the
3208 * cache again, failing at the same point.
3210 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3211 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3212 * inside the following two functions.
3214 static inline void memcg_stop_kmem_account(void)
3216 VM_BUG_ON(!current
->mm
);
3217 current
->memcg_kmem_skip_account
++;
3220 static inline void memcg_resume_kmem_account(void)
3222 VM_BUG_ON(!current
->mm
);
3223 current
->memcg_kmem_skip_account
--;
3226 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3228 struct kmem_cache
*cachep
;
3229 struct memcg_cache_params
*p
;
3231 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3233 cachep
= memcg_params_to_cache(p
);
3236 * If we get down to 0 after shrink, we could delete right away.
3237 * However, memcg_release_pages() already puts us back in the workqueue
3238 * in that case. If we proceed deleting, we'll get a dangling
3239 * reference, and removing the object from the workqueue in that case
3240 * is unnecessary complication. We are not a fast path.
3242 * Note that this case is fundamentally different from racing with
3243 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3244 * kmem_cache_shrink, not only we would be reinserting a dead cache
3245 * into the queue, but doing so from inside the worker racing to
3248 * So if we aren't down to zero, we'll just schedule a worker and try
3251 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0) {
3252 kmem_cache_shrink(cachep
);
3253 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
3256 kmem_cache_destroy(cachep
);
3259 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3261 if (!cachep
->memcg_params
->dead
)
3265 * There are many ways in which we can get here.
3267 * We can get to a memory-pressure situation while the delayed work is
3268 * still pending to run. The vmscan shrinkers can then release all
3269 * cache memory and get us to destruction. If this is the case, we'll
3270 * be executed twice, which is a bug (the second time will execute over
3271 * bogus data). In this case, cancelling the work should be fine.
3273 * But we can also get here from the worker itself, if
3274 * kmem_cache_shrink is enough to shake all the remaining objects and
3275 * get the page count to 0. In this case, we'll deadlock if we try to
3276 * cancel the work (the worker runs with an internal lock held, which
3277 * is the same lock we would hold for cancel_work_sync().)
3279 * Since we can't possibly know who got us here, just refrain from
3280 * running if there is already work pending
3282 if (work_pending(&cachep
->memcg_params
->destroy
))
3285 * We have to defer the actual destroying to a workqueue, because
3286 * we might currently be in a context that cannot sleep.
3288 schedule_work(&cachep
->memcg_params
->destroy
);
3292 * This lock protects updaters, not readers. We want readers to be as fast as
3293 * they can, and they will either see NULL or a valid cache value. Our model
3294 * allow them to see NULL, in which case the root memcg will be selected.
3296 * We need this lock because multiple allocations to the same cache from a non
3297 * will span more than one worker. Only one of them can create the cache.
3299 static DEFINE_MUTEX(memcg_cache_mutex
);
3302 * Called with memcg_cache_mutex held
3304 static struct kmem_cache
*kmem_cache_dup(struct mem_cgroup
*memcg
,
3305 struct kmem_cache
*s
)
3307 struct kmem_cache
*new;
3308 static char *tmp_name
= NULL
;
3310 lockdep_assert_held(&memcg_cache_mutex
);
3313 * kmem_cache_create_memcg duplicates the given name and
3314 * cgroup_name for this name requires RCU context.
3315 * This static temporary buffer is used to prevent from
3316 * pointless shortliving allocation.
3319 tmp_name
= kmalloc(PATH_MAX
, GFP_KERNEL
);
3325 snprintf(tmp_name
, PATH_MAX
, "%s(%d:%s)", s
->name
,
3326 memcg_cache_id(memcg
), cgroup_name(memcg
->css
.cgroup
));
3329 new = kmem_cache_create_memcg(memcg
, tmp_name
, s
->object_size
, s
->align
,
3330 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3333 new->allocflags
|= __GFP_KMEMCG
;
3338 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3339 struct kmem_cache
*cachep
)
3341 struct kmem_cache
*new_cachep
;
3344 BUG_ON(!memcg_can_account_kmem(memcg
));
3346 idx
= memcg_cache_id(memcg
);
3348 mutex_lock(&memcg_cache_mutex
);
3349 new_cachep
= cachep
->memcg_params
->memcg_caches
[idx
];
3351 css_put(&memcg
->css
);
3355 new_cachep
= kmem_cache_dup(memcg
, cachep
);
3356 if (new_cachep
== NULL
) {
3357 new_cachep
= cachep
;
3358 css_put(&memcg
->css
);
3362 atomic_set(&new_cachep
->memcg_params
->nr_pages
, 0);
3364 cachep
->memcg_params
->memcg_caches
[idx
] = new_cachep
;
3366 * the readers won't lock, make sure everybody sees the updated value,
3367 * so they won't put stuff in the queue again for no reason
3371 mutex_unlock(&memcg_cache_mutex
);
3375 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3377 struct kmem_cache
*c
;
3380 if (!s
->memcg_params
)
3382 if (!s
->memcg_params
->is_root_cache
)
3386 * If the cache is being destroyed, we trust that there is no one else
3387 * requesting objects from it. Even if there are, the sanity checks in
3388 * kmem_cache_destroy should caught this ill-case.
3390 * Still, we don't want anyone else freeing memcg_caches under our
3391 * noses, which can happen if a new memcg comes to life. As usual,
3392 * we'll take the set_limit_mutex to protect ourselves against this.
3394 mutex_lock(&set_limit_mutex
);
3395 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3396 c
= s
->memcg_params
->memcg_caches
[i
];
3401 * We will now manually delete the caches, so to avoid races
3402 * we need to cancel all pending destruction workers and
3403 * proceed with destruction ourselves.
3405 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3406 * and that could spawn the workers again: it is likely that
3407 * the cache still have active pages until this very moment.
3408 * This would lead us back to mem_cgroup_destroy_cache.
3410 * But that will not execute at all if the "dead" flag is not
3411 * set, so flip it down to guarantee we are in control.
3413 c
->memcg_params
->dead
= false;
3414 cancel_work_sync(&c
->memcg_params
->destroy
);
3415 kmem_cache_destroy(c
);
3417 mutex_unlock(&set_limit_mutex
);
3420 struct create_work
{
3421 struct mem_cgroup
*memcg
;
3422 struct kmem_cache
*cachep
;
3423 struct work_struct work
;
3426 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3428 struct kmem_cache
*cachep
;
3429 struct memcg_cache_params
*params
;
3431 if (!memcg_kmem_is_active(memcg
))
3434 mutex_lock(&memcg
->slab_caches_mutex
);
3435 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3436 cachep
= memcg_params_to_cache(params
);
3437 cachep
->memcg_params
->dead
= true;
3438 schedule_work(&cachep
->memcg_params
->destroy
);
3440 mutex_unlock(&memcg
->slab_caches_mutex
);
3443 static void memcg_create_cache_work_func(struct work_struct
*w
)
3445 struct create_work
*cw
;
3447 cw
= container_of(w
, struct create_work
, work
);
3448 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3453 * Enqueue the creation of a per-memcg kmem_cache.
3455 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3456 struct kmem_cache
*cachep
)
3458 struct create_work
*cw
;
3460 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3462 css_put(&memcg
->css
);
3467 cw
->cachep
= cachep
;
3469 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3470 schedule_work(&cw
->work
);
3473 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3474 struct kmem_cache
*cachep
)
3477 * We need to stop accounting when we kmalloc, because if the
3478 * corresponding kmalloc cache is not yet created, the first allocation
3479 * in __memcg_create_cache_enqueue will recurse.
3481 * However, it is better to enclose the whole function. Depending on
3482 * the debugging options enabled, INIT_WORK(), for instance, can
3483 * trigger an allocation. This too, will make us recurse. Because at
3484 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3485 * the safest choice is to do it like this, wrapping the whole function.
3487 memcg_stop_kmem_account();
3488 __memcg_create_cache_enqueue(memcg
, cachep
);
3489 memcg_resume_kmem_account();
3492 * Return the kmem_cache we're supposed to use for a slab allocation.
3493 * We try to use the current memcg's version of the cache.
3495 * If the cache does not exist yet, if we are the first user of it,
3496 * we either create it immediately, if possible, or create it asynchronously
3498 * In the latter case, we will let the current allocation go through with
3499 * the original cache.
3501 * Can't be called in interrupt context or from kernel threads.
3502 * This function needs to be called with rcu_read_lock() held.
3504 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3507 struct mem_cgroup
*memcg
;
3510 VM_BUG_ON(!cachep
->memcg_params
);
3511 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3513 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3517 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3519 if (!memcg_can_account_kmem(memcg
))
3522 idx
= memcg_cache_id(memcg
);
3525 * barrier to mare sure we're always seeing the up to date value. The
3526 * code updating memcg_caches will issue a write barrier to match this.
3528 read_barrier_depends();
3529 if (likely(cachep
->memcg_params
->memcg_caches
[idx
])) {
3530 cachep
= cachep
->memcg_params
->memcg_caches
[idx
];
3534 /* The corresponding put will be done in the workqueue. */
3535 if (!css_tryget(&memcg
->css
))
3540 * If we are in a safe context (can wait, and not in interrupt
3541 * context), we could be be predictable and return right away.
3542 * This would guarantee that the allocation being performed
3543 * already belongs in the new cache.
3545 * However, there are some clashes that can arrive from locking.
3546 * For instance, because we acquire the slab_mutex while doing
3547 * kmem_cache_dup, this means no further allocation could happen
3548 * with the slab_mutex held.
3550 * Also, because cache creation issue get_online_cpus(), this
3551 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3552 * that ends up reversed during cpu hotplug. (cpuset allocates
3553 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3554 * better to defer everything.
3556 memcg_create_cache_enqueue(memcg
, cachep
);
3562 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3565 * We need to verify if the allocation against current->mm->owner's memcg is
3566 * possible for the given order. But the page is not allocated yet, so we'll
3567 * need a further commit step to do the final arrangements.
3569 * It is possible for the task to switch cgroups in this mean time, so at
3570 * commit time, we can't rely on task conversion any longer. We'll then use
3571 * the handle argument to return to the caller which cgroup we should commit
3572 * against. We could also return the memcg directly and avoid the pointer
3573 * passing, but a boolean return value gives better semantics considering
3574 * the compiled-out case as well.
3576 * Returning true means the allocation is possible.
3579 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3581 struct mem_cgroup
*memcg
;
3587 * Disabling accounting is only relevant for some specific memcg
3588 * internal allocations. Therefore we would initially not have such
3589 * check here, since direct calls to the page allocator that are marked
3590 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3591 * concerned with cache allocations, and by having this test at
3592 * memcg_kmem_get_cache, we are already able to relay the allocation to
3593 * the root cache and bypass the memcg cache altogether.
3595 * There is one exception, though: the SLUB allocator does not create
3596 * large order caches, but rather service large kmallocs directly from
3597 * the page allocator. Therefore, the following sequence when backed by
3598 * the SLUB allocator:
3600 * memcg_stop_kmem_account();
3601 * kmalloc(<large_number>)
3602 * memcg_resume_kmem_account();
3604 * would effectively ignore the fact that we should skip accounting,
3605 * since it will drive us directly to this function without passing
3606 * through the cache selector memcg_kmem_get_cache. Such large
3607 * allocations are extremely rare but can happen, for instance, for the
3608 * cache arrays. We bring this test here.
3610 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3613 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3616 * very rare case described in mem_cgroup_from_task. Unfortunately there
3617 * isn't much we can do without complicating this too much, and it would
3618 * be gfp-dependent anyway. Just let it go
3620 if (unlikely(!memcg
))
3623 if (!memcg_can_account_kmem(memcg
)) {
3624 css_put(&memcg
->css
);
3628 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3632 css_put(&memcg
->css
);
3636 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3639 struct page_cgroup
*pc
;
3641 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3643 /* The page allocation failed. Revert */
3645 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3649 pc
= lookup_page_cgroup(page
);
3650 lock_page_cgroup(pc
);
3651 pc
->mem_cgroup
= memcg
;
3652 SetPageCgroupUsed(pc
);
3653 unlock_page_cgroup(pc
);
3656 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3658 struct mem_cgroup
*memcg
= NULL
;
3659 struct page_cgroup
*pc
;
3662 pc
= lookup_page_cgroup(page
);
3664 * Fast unlocked return. Theoretically might have changed, have to
3665 * check again after locking.
3667 if (!PageCgroupUsed(pc
))
3670 lock_page_cgroup(pc
);
3671 if (PageCgroupUsed(pc
)) {
3672 memcg
= pc
->mem_cgroup
;
3673 ClearPageCgroupUsed(pc
);
3675 unlock_page_cgroup(pc
);
3678 * We trust that only if there is a memcg associated with the page, it
3679 * is a valid allocation
3684 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3685 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3688 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3691 #endif /* CONFIG_MEMCG_KMEM */
3693 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3695 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3697 * Because tail pages are not marked as "used", set it. We're under
3698 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3699 * charge/uncharge will be never happen and move_account() is done under
3700 * compound_lock(), so we don't have to take care of races.
3702 void mem_cgroup_split_huge_fixup(struct page
*head
)
3704 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3705 struct page_cgroup
*pc
;
3706 struct mem_cgroup
*memcg
;
3709 if (mem_cgroup_disabled())
3712 memcg
= head_pc
->mem_cgroup
;
3713 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3715 pc
->mem_cgroup
= memcg
;
3716 smp_wmb();/* see __commit_charge() */
3717 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3719 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
3722 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3725 * mem_cgroup_move_account - move account of the page
3727 * @nr_pages: number of regular pages (>1 for huge pages)
3728 * @pc: page_cgroup of the page.
3729 * @from: mem_cgroup which the page is moved from.
3730 * @to: mem_cgroup which the page is moved to. @from != @to.
3732 * The caller must confirm following.
3733 * - page is not on LRU (isolate_page() is useful.)
3734 * - compound_lock is held when nr_pages > 1
3736 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3739 static int mem_cgroup_move_account(struct page
*page
,
3740 unsigned int nr_pages
,
3741 struct page_cgroup
*pc
,
3742 struct mem_cgroup
*from
,
3743 struct mem_cgroup
*to
)
3745 unsigned long flags
;
3747 bool anon
= PageAnon(page
);
3749 VM_BUG_ON(from
== to
);
3750 VM_BUG_ON(PageLRU(page
));
3752 * The page is isolated from LRU. So, collapse function
3753 * will not handle this page. But page splitting can happen.
3754 * Do this check under compound_page_lock(). The caller should
3758 if (nr_pages
> 1 && !PageTransHuge(page
))
3761 lock_page_cgroup(pc
);
3764 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3767 move_lock_mem_cgroup(from
, &flags
);
3769 if (!anon
&& page_mapped(page
)) {
3770 /* Update mapped_file data for mem_cgroup */
3772 __this_cpu_dec(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3773 __this_cpu_inc(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
3776 mem_cgroup_charge_statistics(from
, page
, anon
, -nr_pages
);
3778 /* caller should have done css_get */
3779 pc
->mem_cgroup
= to
;
3780 mem_cgroup_charge_statistics(to
, page
, anon
, nr_pages
);
3781 move_unlock_mem_cgroup(from
, &flags
);
3784 unlock_page_cgroup(pc
);
3788 memcg_check_events(to
, page
);
3789 memcg_check_events(from
, page
);
3795 * mem_cgroup_move_parent - moves page to the parent group
3796 * @page: the page to move
3797 * @pc: page_cgroup of the page
3798 * @child: page's cgroup
3800 * move charges to its parent or the root cgroup if the group has no
3801 * parent (aka use_hierarchy==0).
3802 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3803 * mem_cgroup_move_account fails) the failure is always temporary and
3804 * it signals a race with a page removal/uncharge or migration. In the
3805 * first case the page is on the way out and it will vanish from the LRU
3806 * on the next attempt and the call should be retried later.
3807 * Isolation from the LRU fails only if page has been isolated from
3808 * the LRU since we looked at it and that usually means either global
3809 * reclaim or migration going on. The page will either get back to the
3811 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3812 * (!PageCgroupUsed) or moved to a different group. The page will
3813 * disappear in the next attempt.
3815 static int mem_cgroup_move_parent(struct page
*page
,
3816 struct page_cgroup
*pc
,
3817 struct mem_cgroup
*child
)
3819 struct mem_cgroup
*parent
;
3820 unsigned int nr_pages
;
3821 unsigned long uninitialized_var(flags
);
3824 VM_BUG_ON(mem_cgroup_is_root(child
));
3827 if (!get_page_unless_zero(page
))
3829 if (isolate_lru_page(page
))
3832 nr_pages
= hpage_nr_pages(page
);
3834 parent
= parent_mem_cgroup(child
);
3836 * If no parent, move charges to root cgroup.
3839 parent
= root_mem_cgroup
;
3842 VM_BUG_ON(!PageTransHuge(page
));
3843 flags
= compound_lock_irqsave(page
);
3846 ret
= mem_cgroup_move_account(page
, nr_pages
,
3849 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3852 compound_unlock_irqrestore(page
, flags
);
3853 putback_lru_page(page
);
3861 * Charge the memory controller for page usage.
3863 * 0 if the charge was successful
3864 * < 0 if the cgroup is over its limit
3866 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
3867 gfp_t gfp_mask
, enum charge_type ctype
)
3869 struct mem_cgroup
*memcg
= NULL
;
3870 unsigned int nr_pages
= 1;
3874 if (PageTransHuge(page
)) {
3875 nr_pages
<<= compound_order(page
);
3876 VM_BUG_ON(!PageTransHuge(page
));
3878 * Never OOM-kill a process for a huge page. The
3879 * fault handler will fall back to regular pages.
3884 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
3887 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
3891 int mem_cgroup_newpage_charge(struct page
*page
,
3892 struct mm_struct
*mm
, gfp_t gfp_mask
)
3894 if (mem_cgroup_disabled())
3896 VM_BUG_ON(page_mapped(page
));
3897 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
3899 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
3900 MEM_CGROUP_CHARGE_TYPE_ANON
);
3904 * While swap-in, try_charge -> commit or cancel, the page is locked.
3905 * And when try_charge() successfully returns, one refcnt to memcg without
3906 * struct page_cgroup is acquired. This refcnt will be consumed by
3907 * "commit()" or removed by "cancel()"
3909 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
3912 struct mem_cgroup
**memcgp
)
3914 struct mem_cgroup
*memcg
;
3915 struct page_cgroup
*pc
;
3918 pc
= lookup_page_cgroup(page
);
3920 * Every swap fault against a single page tries to charge the
3921 * page, bail as early as possible. shmem_unuse() encounters
3922 * already charged pages, too. The USED bit is protected by
3923 * the page lock, which serializes swap cache removal, which
3924 * in turn serializes uncharging.
3926 if (PageCgroupUsed(pc
))
3928 if (!do_swap_account
)
3930 memcg
= try_get_mem_cgroup_from_page(page
);
3934 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
3935 css_put(&memcg
->css
);
3940 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
3946 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
3947 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
3950 if (mem_cgroup_disabled())
3953 * A racing thread's fault, or swapoff, may have already
3954 * updated the pte, and even removed page from swap cache: in
3955 * those cases unuse_pte()'s pte_same() test will fail; but
3956 * there's also a KSM case which does need to charge the page.
3958 if (!PageSwapCache(page
)) {
3961 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
3966 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
3969 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
3971 if (mem_cgroup_disabled())
3975 __mem_cgroup_cancel_charge(memcg
, 1);
3979 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
3980 enum charge_type ctype
)
3982 if (mem_cgroup_disabled())
3987 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
3989 * Now swap is on-memory. This means this page may be
3990 * counted both as mem and swap....double count.
3991 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
3992 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
3993 * may call delete_from_swap_cache() before reach here.
3995 if (do_swap_account
&& PageSwapCache(page
)) {
3996 swp_entry_t ent
= {.val
= page_private(page
)};
3997 mem_cgroup_uncharge_swap(ent
);
4001 void mem_cgroup_commit_charge_swapin(struct page
*page
,
4002 struct mem_cgroup
*memcg
)
4004 __mem_cgroup_commit_charge_swapin(page
, memcg
,
4005 MEM_CGROUP_CHARGE_TYPE_ANON
);
4008 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
4011 struct mem_cgroup
*memcg
= NULL
;
4012 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4015 if (mem_cgroup_disabled())
4017 if (PageCompound(page
))
4020 if (!PageSwapCache(page
))
4021 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
4022 else { /* page is swapcache/shmem */
4023 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
4026 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
4031 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
4032 unsigned int nr_pages
,
4033 const enum charge_type ctype
)
4035 struct memcg_batch_info
*batch
= NULL
;
4036 bool uncharge_memsw
= true;
4038 /* If swapout, usage of swap doesn't decrease */
4039 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
4040 uncharge_memsw
= false;
4042 batch
= ¤t
->memcg_batch
;
4044 * In usual, we do css_get() when we remember memcg pointer.
4045 * But in this case, we keep res->usage until end of a series of
4046 * uncharges. Then, it's ok to ignore memcg's refcnt.
4049 batch
->memcg
= memcg
;
4051 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
4052 * In those cases, all pages freed continuously can be expected to be in
4053 * the same cgroup and we have chance to coalesce uncharges.
4054 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
4055 * because we want to do uncharge as soon as possible.
4058 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
4059 goto direct_uncharge
;
4062 goto direct_uncharge
;
4065 * In typical case, batch->memcg == mem. This means we can
4066 * merge a series of uncharges to an uncharge of res_counter.
4067 * If not, we uncharge res_counter ony by one.
4069 if (batch
->memcg
!= memcg
)
4070 goto direct_uncharge
;
4071 /* remember freed charge and uncharge it later */
4074 batch
->memsw_nr_pages
++;
4077 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
4079 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
4080 if (unlikely(batch
->memcg
!= memcg
))
4081 memcg_oom_recover(memcg
);
4085 * uncharge if !page_mapped(page)
4087 static struct mem_cgroup
*
4088 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
4091 struct mem_cgroup
*memcg
= NULL
;
4092 unsigned int nr_pages
= 1;
4093 struct page_cgroup
*pc
;
4096 if (mem_cgroup_disabled())
4099 if (PageTransHuge(page
)) {
4100 nr_pages
<<= compound_order(page
);
4101 VM_BUG_ON(!PageTransHuge(page
));
4104 * Check if our page_cgroup is valid
4106 pc
= lookup_page_cgroup(page
);
4107 if (unlikely(!PageCgroupUsed(pc
)))
4110 lock_page_cgroup(pc
);
4112 memcg
= pc
->mem_cgroup
;
4114 if (!PageCgroupUsed(pc
))
4117 anon
= PageAnon(page
);
4120 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4122 * Generally PageAnon tells if it's the anon statistics to be
4123 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4124 * used before page reached the stage of being marked PageAnon.
4128 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4129 /* See mem_cgroup_prepare_migration() */
4130 if (page_mapped(page
))
4133 * Pages under migration may not be uncharged. But
4134 * end_migration() /must/ be the one uncharging the
4135 * unused post-migration page and so it has to call
4136 * here with the migration bit still set. See the
4137 * res_counter handling below.
4139 if (!end_migration
&& PageCgroupMigration(pc
))
4142 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4143 if (!PageAnon(page
)) { /* Shared memory */
4144 if (page
->mapping
&& !page_is_file_cache(page
))
4146 } else if (page_mapped(page
)) /* Anon */
4153 mem_cgroup_charge_statistics(memcg
, page
, anon
, -nr_pages
);
4155 ClearPageCgroupUsed(pc
);
4157 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4158 * freed from LRU. This is safe because uncharged page is expected not
4159 * to be reused (freed soon). Exception is SwapCache, it's handled by
4160 * special functions.
4163 unlock_page_cgroup(pc
);
4165 * even after unlock, we have memcg->res.usage here and this memcg
4166 * will never be freed, so it's safe to call css_get().
4168 memcg_check_events(memcg
, page
);
4169 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4170 mem_cgroup_swap_statistics(memcg
, true);
4171 css_get(&memcg
->css
);
4174 * Migration does not charge the res_counter for the
4175 * replacement page, so leave it alone when phasing out the
4176 * page that is unused after the migration.
4178 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4179 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4184 unlock_page_cgroup(pc
);
4188 void mem_cgroup_uncharge_page(struct page
*page
)
4191 if (page_mapped(page
))
4193 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
4195 * If the page is in swap cache, uncharge should be deferred
4196 * to the swap path, which also properly accounts swap usage
4197 * and handles memcg lifetime.
4199 * Note that this check is not stable and reclaim may add the
4200 * page to swap cache at any time after this. However, if the
4201 * page is not in swap cache by the time page->mapcount hits
4202 * 0, there won't be any page table references to the swap
4203 * slot, and reclaim will free it and not actually write the
4206 if (PageSwapCache(page
))
4208 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4211 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4213 VM_BUG_ON(page_mapped(page
));
4214 VM_BUG_ON(page
->mapping
);
4215 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4219 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4220 * In that cases, pages are freed continuously and we can expect pages
4221 * are in the same memcg. All these calls itself limits the number of
4222 * pages freed at once, then uncharge_start/end() is called properly.
4223 * This may be called prural(2) times in a context,
4226 void mem_cgroup_uncharge_start(void)
4228 current
->memcg_batch
.do_batch
++;
4229 /* We can do nest. */
4230 if (current
->memcg_batch
.do_batch
== 1) {
4231 current
->memcg_batch
.memcg
= NULL
;
4232 current
->memcg_batch
.nr_pages
= 0;
4233 current
->memcg_batch
.memsw_nr_pages
= 0;
4237 void mem_cgroup_uncharge_end(void)
4239 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4241 if (!batch
->do_batch
)
4245 if (batch
->do_batch
) /* If stacked, do nothing. */
4251 * This "batch->memcg" is valid without any css_get/put etc...
4252 * bacause we hide charges behind us.
4254 if (batch
->nr_pages
)
4255 res_counter_uncharge(&batch
->memcg
->res
,
4256 batch
->nr_pages
* PAGE_SIZE
);
4257 if (batch
->memsw_nr_pages
)
4258 res_counter_uncharge(&batch
->memcg
->memsw
,
4259 batch
->memsw_nr_pages
* PAGE_SIZE
);
4260 memcg_oom_recover(batch
->memcg
);
4261 /* forget this pointer (for sanity check) */
4262 batch
->memcg
= NULL
;
4267 * called after __delete_from_swap_cache() and drop "page" account.
4268 * memcg information is recorded to swap_cgroup of "ent"
4271 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4273 struct mem_cgroup
*memcg
;
4274 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4276 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4277 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4279 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4282 * record memcg information, if swapout && memcg != NULL,
4283 * css_get() was called in uncharge().
4285 if (do_swap_account
&& swapout
&& memcg
)
4286 swap_cgroup_record(ent
, css_id(&memcg
->css
));
4290 #ifdef CONFIG_MEMCG_SWAP
4292 * called from swap_entry_free(). remove record in swap_cgroup and
4293 * uncharge "memsw" account.
4295 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4297 struct mem_cgroup
*memcg
;
4300 if (!do_swap_account
)
4303 id
= swap_cgroup_record(ent
, 0);
4305 memcg
= mem_cgroup_lookup(id
);
4308 * We uncharge this because swap is freed.
4309 * This memcg can be obsolete one. We avoid calling css_tryget
4311 if (!mem_cgroup_is_root(memcg
))
4312 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4313 mem_cgroup_swap_statistics(memcg
, false);
4314 css_put(&memcg
->css
);
4320 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4321 * @entry: swap entry to be moved
4322 * @from: mem_cgroup which the entry is moved from
4323 * @to: mem_cgroup which the entry is moved to
4325 * It succeeds only when the swap_cgroup's record for this entry is the same
4326 * as the mem_cgroup's id of @from.
4328 * Returns 0 on success, -EINVAL on failure.
4330 * The caller must have charged to @to, IOW, called res_counter_charge() about
4331 * both res and memsw, and called css_get().
4333 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4334 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4336 unsigned short old_id
, new_id
;
4338 old_id
= css_id(&from
->css
);
4339 new_id
= css_id(&to
->css
);
4341 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4342 mem_cgroup_swap_statistics(from
, false);
4343 mem_cgroup_swap_statistics(to
, true);
4345 * This function is only called from task migration context now.
4346 * It postpones res_counter and refcount handling till the end
4347 * of task migration(mem_cgroup_clear_mc()) for performance
4348 * improvement. But we cannot postpone css_get(to) because if
4349 * the process that has been moved to @to does swap-in, the
4350 * refcount of @to might be decreased to 0.
4352 * We are in attach() phase, so the cgroup is guaranteed to be
4353 * alive, so we can just call css_get().
4361 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4362 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4369 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4372 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4373 struct mem_cgroup
**memcgp
)
4375 struct mem_cgroup
*memcg
= NULL
;
4376 unsigned int nr_pages
= 1;
4377 struct page_cgroup
*pc
;
4378 enum charge_type ctype
;
4382 if (mem_cgroup_disabled())
4385 if (PageTransHuge(page
))
4386 nr_pages
<<= compound_order(page
);
4388 pc
= lookup_page_cgroup(page
);
4389 lock_page_cgroup(pc
);
4390 if (PageCgroupUsed(pc
)) {
4391 memcg
= pc
->mem_cgroup
;
4392 css_get(&memcg
->css
);
4394 * At migrating an anonymous page, its mapcount goes down
4395 * to 0 and uncharge() will be called. But, even if it's fully
4396 * unmapped, migration may fail and this page has to be
4397 * charged again. We set MIGRATION flag here and delay uncharge
4398 * until end_migration() is called
4400 * Corner Case Thinking
4402 * When the old page was mapped as Anon and it's unmap-and-freed
4403 * while migration was ongoing.
4404 * If unmap finds the old page, uncharge() of it will be delayed
4405 * until end_migration(). If unmap finds a new page, it's
4406 * uncharged when it make mapcount to be 1->0. If unmap code
4407 * finds swap_migration_entry, the new page will not be mapped
4408 * and end_migration() will find it(mapcount==0).
4411 * When the old page was mapped but migraion fails, the kernel
4412 * remaps it. A charge for it is kept by MIGRATION flag even
4413 * if mapcount goes down to 0. We can do remap successfully
4414 * without charging it again.
4417 * The "old" page is under lock_page() until the end of
4418 * migration, so, the old page itself will not be swapped-out.
4419 * If the new page is swapped out before end_migraton, our
4420 * hook to usual swap-out path will catch the event.
4423 SetPageCgroupMigration(pc
);
4425 unlock_page_cgroup(pc
);
4427 * If the page is not charged at this point,
4435 * We charge new page before it's used/mapped. So, even if unlock_page()
4436 * is called before end_migration, we can catch all events on this new
4437 * page. In the case new page is migrated but not remapped, new page's
4438 * mapcount will be finally 0 and we call uncharge in end_migration().
4441 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4443 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4445 * The page is committed to the memcg, but it's not actually
4446 * charged to the res_counter since we plan on replacing the
4447 * old one and only one page is going to be left afterwards.
4449 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4452 /* remove redundant charge if migration failed*/
4453 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4454 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4456 struct page
*used
, *unused
;
4457 struct page_cgroup
*pc
;
4463 if (!migration_ok
) {
4470 anon
= PageAnon(used
);
4471 __mem_cgroup_uncharge_common(unused
,
4472 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4473 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4475 css_put(&memcg
->css
);
4477 * We disallowed uncharge of pages under migration because mapcount
4478 * of the page goes down to zero, temporarly.
4479 * Clear the flag and check the page should be charged.
4481 pc
= lookup_page_cgroup(oldpage
);
4482 lock_page_cgroup(pc
);
4483 ClearPageCgroupMigration(pc
);
4484 unlock_page_cgroup(pc
);
4487 * If a page is a file cache, radix-tree replacement is very atomic
4488 * and we can skip this check. When it was an Anon page, its mapcount
4489 * goes down to 0. But because we added MIGRATION flage, it's not
4490 * uncharged yet. There are several case but page->mapcount check
4491 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4492 * check. (see prepare_charge() also)
4495 mem_cgroup_uncharge_page(used
);
4499 * At replace page cache, newpage is not under any memcg but it's on
4500 * LRU. So, this function doesn't touch res_counter but handles LRU
4501 * in correct way. Both pages are locked so we cannot race with uncharge.
4503 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4504 struct page
*newpage
)
4506 struct mem_cgroup
*memcg
= NULL
;
4507 struct page_cgroup
*pc
;
4508 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4510 if (mem_cgroup_disabled())
4513 pc
= lookup_page_cgroup(oldpage
);
4514 /* fix accounting on old pages */
4515 lock_page_cgroup(pc
);
4516 if (PageCgroupUsed(pc
)) {
4517 memcg
= pc
->mem_cgroup
;
4518 mem_cgroup_charge_statistics(memcg
, oldpage
, false, -1);
4519 ClearPageCgroupUsed(pc
);
4521 unlock_page_cgroup(pc
);
4524 * When called from shmem_replace_page(), in some cases the
4525 * oldpage has already been charged, and in some cases not.
4530 * Even if newpage->mapping was NULL before starting replacement,
4531 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4532 * LRU while we overwrite pc->mem_cgroup.
4534 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4537 #ifdef CONFIG_DEBUG_VM
4538 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4540 struct page_cgroup
*pc
;
4542 pc
= lookup_page_cgroup(page
);
4544 * Can be NULL while feeding pages into the page allocator for
4545 * the first time, i.e. during boot or memory hotplug;
4546 * or when mem_cgroup_disabled().
4548 if (likely(pc
) && PageCgroupUsed(pc
))
4553 bool mem_cgroup_bad_page_check(struct page
*page
)
4555 if (mem_cgroup_disabled())
4558 return lookup_page_cgroup_used(page
) != NULL
;
4561 void mem_cgroup_print_bad_page(struct page
*page
)
4563 struct page_cgroup
*pc
;
4565 pc
= lookup_page_cgroup_used(page
);
4567 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4568 pc
, pc
->flags
, pc
->mem_cgroup
);
4573 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4574 unsigned long long val
)
4577 u64 memswlimit
, memlimit
;
4579 int children
= mem_cgroup_count_children(memcg
);
4580 u64 curusage
, oldusage
;
4584 * For keeping hierarchical_reclaim simple, how long we should retry
4585 * is depends on callers. We set our retry-count to be function
4586 * of # of children which we should visit in this loop.
4588 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4590 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4593 while (retry_count
) {
4594 if (signal_pending(current
)) {
4599 * Rather than hide all in some function, I do this in
4600 * open coded manner. You see what this really does.
4601 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4603 mutex_lock(&set_limit_mutex
);
4604 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4605 if (memswlimit
< val
) {
4607 mutex_unlock(&set_limit_mutex
);
4611 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4615 ret
= res_counter_set_limit(&memcg
->res
, val
);
4617 if (memswlimit
== val
)
4618 memcg
->memsw_is_minimum
= true;
4620 memcg
->memsw_is_minimum
= false;
4622 mutex_unlock(&set_limit_mutex
);
4627 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4628 MEM_CGROUP_RECLAIM_SHRINK
);
4629 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4630 /* Usage is reduced ? */
4631 if (curusage
>= oldusage
)
4634 oldusage
= curusage
;
4636 if (!ret
&& enlarge
)
4637 memcg_oom_recover(memcg
);
4642 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4643 unsigned long long val
)
4646 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4647 int children
= mem_cgroup_count_children(memcg
);
4651 /* see mem_cgroup_resize_res_limit */
4652 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4653 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4654 while (retry_count
) {
4655 if (signal_pending(current
)) {
4660 * Rather than hide all in some function, I do this in
4661 * open coded manner. You see what this really does.
4662 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4664 mutex_lock(&set_limit_mutex
);
4665 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4666 if (memlimit
> val
) {
4668 mutex_unlock(&set_limit_mutex
);
4671 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4672 if (memswlimit
< val
)
4674 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4676 if (memlimit
== val
)
4677 memcg
->memsw_is_minimum
= true;
4679 memcg
->memsw_is_minimum
= false;
4681 mutex_unlock(&set_limit_mutex
);
4686 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4687 MEM_CGROUP_RECLAIM_NOSWAP
|
4688 MEM_CGROUP_RECLAIM_SHRINK
);
4689 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4690 /* Usage is reduced ? */
4691 if (curusage
>= oldusage
)
4694 oldusage
= curusage
;
4696 if (!ret
&& enlarge
)
4697 memcg_oom_recover(memcg
);
4702 * mem_cgroup_force_empty_list - clears LRU of a group
4703 * @memcg: group to clear
4706 * @lru: lru to to clear
4708 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4709 * reclaim the pages page themselves - pages are moved to the parent (or root)
4712 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4713 int node
, int zid
, enum lru_list lru
)
4715 struct lruvec
*lruvec
;
4716 unsigned long flags
;
4717 struct list_head
*list
;
4721 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4722 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4723 list
= &lruvec
->lists
[lru
];
4727 struct page_cgroup
*pc
;
4730 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4731 if (list_empty(list
)) {
4732 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4735 page
= list_entry(list
->prev
, struct page
, lru
);
4737 list_move(&page
->lru
, list
);
4739 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4742 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4744 pc
= lookup_page_cgroup(page
);
4746 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4747 /* found lock contention or "pc" is obsolete. */
4752 } while (!list_empty(list
));
4756 * make mem_cgroup's charge to be 0 if there is no task by moving
4757 * all the charges and pages to the parent.
4758 * This enables deleting this mem_cgroup.
4760 * Caller is responsible for holding css reference on the memcg.
4762 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4768 /* This is for making all *used* pages to be on LRU. */
4769 lru_add_drain_all();
4770 drain_all_stock_sync(memcg
);
4771 mem_cgroup_start_move(memcg
);
4772 for_each_node_state(node
, N_MEMORY
) {
4773 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4776 mem_cgroup_force_empty_list(memcg
,
4781 mem_cgroup_end_move(memcg
);
4782 memcg_oom_recover(memcg
);
4786 * Kernel memory may not necessarily be trackable to a specific
4787 * process. So they are not migrated, and therefore we can't
4788 * expect their value to drop to 0 here.
4789 * Having res filled up with kmem only is enough.
4791 * This is a safety check because mem_cgroup_force_empty_list
4792 * could have raced with mem_cgroup_replace_page_cache callers
4793 * so the lru seemed empty but the page could have been added
4794 * right after the check. RES_USAGE should be safe as we always
4795 * charge before adding to the LRU.
4797 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
4798 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
4799 } while (usage
> 0);
4803 * This mainly exists for tests during the setting of set of use_hierarchy.
4804 * Since this is the very setting we are changing, the current hierarchy value
4807 static inline bool __memcg_has_children(struct mem_cgroup
*memcg
)
4809 struct cgroup_subsys_state
*pos
;
4811 /* bounce at first found */
4812 css_for_each_child(pos
, &memcg
->css
)
4818 * Must be called with memcg_create_mutex held, unless the cgroup is guaranteed
4819 * to be already dead (as in mem_cgroup_force_empty, for instance). This is
4820 * from mem_cgroup_count_children(), in the sense that we don't really care how
4821 * many children we have; we only need to know if we have any. It also counts
4822 * any memcg without hierarchy as infertile.
4824 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
4826 return memcg
->use_hierarchy
&& __memcg_has_children(memcg
);
4830 * Reclaims as many pages from the given memcg as possible and moves
4831 * the rest to the parent.
4833 * Caller is responsible for holding css reference for memcg.
4835 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
4837 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
4838 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
4840 /* returns EBUSY if there is a task or if we come here twice. */
4841 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
4844 /* we call try-to-free pages for make this cgroup empty */
4845 lru_add_drain_all();
4846 /* try to free all pages in this cgroup */
4847 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
4850 if (signal_pending(current
))
4853 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
4857 /* maybe some writeback is necessary */
4858 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
4863 mem_cgroup_reparent_charges(memcg
);
4868 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state
*css
,
4871 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4873 if (mem_cgroup_is_root(memcg
))
4875 return mem_cgroup_force_empty(memcg
);
4878 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
4881 return mem_cgroup_from_css(css
)->use_hierarchy
;
4884 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
4885 struct cftype
*cft
, u64 val
)
4888 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4889 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
4891 mutex_lock(&memcg_create_mutex
);
4893 if (memcg
->use_hierarchy
== val
)
4897 * If parent's use_hierarchy is set, we can't make any modifications
4898 * in the child subtrees. If it is unset, then the change can
4899 * occur, provided the current cgroup has no children.
4901 * For the root cgroup, parent_mem is NULL, we allow value to be
4902 * set if there are no children.
4904 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
4905 (val
== 1 || val
== 0)) {
4906 if (!__memcg_has_children(memcg
))
4907 memcg
->use_hierarchy
= val
;
4914 mutex_unlock(&memcg_create_mutex
);
4920 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
4921 enum mem_cgroup_stat_index idx
)
4923 struct mem_cgroup
*iter
;
4926 /* Per-cpu values can be negative, use a signed accumulator */
4927 for_each_mem_cgroup_tree(iter
, memcg
)
4928 val
+= mem_cgroup_read_stat(iter
, idx
);
4930 if (val
< 0) /* race ? */
4935 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
4939 if (!mem_cgroup_is_root(memcg
)) {
4941 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4943 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4947 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
4948 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
4950 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
4951 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
4954 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
4956 return val
<< PAGE_SHIFT
;
4959 static ssize_t
mem_cgroup_read(struct cgroup_subsys_state
*css
,
4960 struct cftype
*cft
, struct file
*file
,
4961 char __user
*buf
, size_t nbytes
, loff_t
*ppos
)
4963 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4969 type
= MEMFILE_TYPE(cft
->private);
4970 name
= MEMFILE_ATTR(cft
->private);
4974 if (name
== RES_USAGE
)
4975 val
= mem_cgroup_usage(memcg
, false);
4977 val
= res_counter_read_u64(&memcg
->res
, name
);
4980 if (name
== RES_USAGE
)
4981 val
= mem_cgroup_usage(memcg
, true);
4983 val
= res_counter_read_u64(&memcg
->memsw
, name
);
4986 val
= res_counter_read_u64(&memcg
->kmem
, name
);
4992 len
= scnprintf(str
, sizeof(str
), "%llu\n", (unsigned long long)val
);
4993 return simple_read_from_buffer(buf
, nbytes
, ppos
, str
, len
);
4996 static int memcg_update_kmem_limit(struct cgroup_subsys_state
*css
, u64 val
)
4999 #ifdef CONFIG_MEMCG_KMEM
5000 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5002 * For simplicity, we won't allow this to be disabled. It also can't
5003 * be changed if the cgroup has children already, or if tasks had
5006 * If tasks join before we set the limit, a person looking at
5007 * kmem.usage_in_bytes will have no way to determine when it took
5008 * place, which makes the value quite meaningless.
5010 * After it first became limited, changes in the value of the limit are
5011 * of course permitted.
5013 mutex_lock(&memcg_create_mutex
);
5014 mutex_lock(&set_limit_mutex
);
5015 if (!memcg
->kmem_account_flags
&& val
!= RESOURCE_MAX
) {
5016 if (cgroup_task_count(css
->cgroup
) || memcg_has_children(memcg
)) {
5020 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5023 ret
= memcg_update_cache_sizes(memcg
);
5025 res_counter_set_limit(&memcg
->kmem
, RESOURCE_MAX
);
5028 static_key_slow_inc(&memcg_kmem_enabled_key
);
5030 * setting the active bit after the inc will guarantee no one
5031 * starts accounting before all call sites are patched
5033 memcg_kmem_set_active(memcg
);
5035 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5037 mutex_unlock(&set_limit_mutex
);
5038 mutex_unlock(&memcg_create_mutex
);
5043 #ifdef CONFIG_MEMCG_KMEM
5044 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5047 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5051 memcg
->kmem_account_flags
= parent
->kmem_account_flags
;
5053 * When that happen, we need to disable the static branch only on those
5054 * memcgs that enabled it. To achieve this, we would be forced to
5055 * complicate the code by keeping track of which memcgs were the ones
5056 * that actually enabled limits, and which ones got it from its
5059 * It is a lot simpler just to do static_key_slow_inc() on every child
5060 * that is accounted.
5062 if (!memcg_kmem_is_active(memcg
))
5066 * __mem_cgroup_free() will issue static_key_slow_dec() because this
5067 * memcg is active already. If the later initialization fails then the
5068 * cgroup core triggers the cleanup so we do not have to do it here.
5070 static_key_slow_inc(&memcg_kmem_enabled_key
);
5072 mutex_lock(&set_limit_mutex
);
5073 memcg_stop_kmem_account();
5074 ret
= memcg_update_cache_sizes(memcg
);
5075 memcg_resume_kmem_account();
5076 mutex_unlock(&set_limit_mutex
);
5080 #endif /* CONFIG_MEMCG_KMEM */
5083 * The user of this function is...
5086 static int mem_cgroup_write(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
5089 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5092 unsigned long long val
;
5095 type
= MEMFILE_TYPE(cft
->private);
5096 name
= MEMFILE_ATTR(cft
->private);
5100 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5104 /* This function does all necessary parse...reuse it */
5105 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5109 ret
= mem_cgroup_resize_limit(memcg
, val
);
5110 else if (type
== _MEMSWAP
)
5111 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5112 else if (type
== _KMEM
)
5113 ret
= memcg_update_kmem_limit(css
, val
);
5117 case RES_SOFT_LIMIT
:
5118 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5122 * For memsw, soft limits are hard to implement in terms
5123 * of semantics, for now, we support soft limits for
5124 * control without swap
5127 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5132 ret
= -EINVAL
; /* should be BUG() ? */
5138 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5139 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5141 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5143 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5144 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5145 if (!memcg
->use_hierarchy
)
5148 while (css_parent(&memcg
->css
)) {
5149 memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5150 if (!memcg
->use_hierarchy
)
5152 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5153 min_limit
= min(min_limit
, tmp
);
5154 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5155 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5158 *mem_limit
= min_limit
;
5159 *memsw_limit
= min_memsw_limit
;
5162 static int mem_cgroup_reset(struct cgroup_subsys_state
*css
, unsigned int event
)
5164 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5168 type
= MEMFILE_TYPE(event
);
5169 name
= MEMFILE_ATTR(event
);
5174 res_counter_reset_max(&memcg
->res
);
5175 else if (type
== _MEMSWAP
)
5176 res_counter_reset_max(&memcg
->memsw
);
5177 else if (type
== _KMEM
)
5178 res_counter_reset_max(&memcg
->kmem
);
5184 res_counter_reset_failcnt(&memcg
->res
);
5185 else if (type
== _MEMSWAP
)
5186 res_counter_reset_failcnt(&memcg
->memsw
);
5187 else if (type
== _KMEM
)
5188 res_counter_reset_failcnt(&memcg
->kmem
);
5197 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
5200 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
5204 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5205 struct cftype
*cft
, u64 val
)
5207 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5209 if (val
>= (1 << NR_MOVE_TYPE
))
5213 * No kind of locking is needed in here, because ->can_attach() will
5214 * check this value once in the beginning of the process, and then carry
5215 * on with stale data. This means that changes to this value will only
5216 * affect task migrations starting after the change.
5218 memcg
->move_charge_at_immigrate
= val
;
5222 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5223 struct cftype
*cft
, u64 val
)
5230 static int memcg_numa_stat_show(struct cgroup_subsys_state
*css
,
5231 struct cftype
*cft
, struct seq_file
*m
)
5234 unsigned long total_nr
, file_nr
, anon_nr
, unevictable_nr
;
5235 unsigned long node_nr
;
5236 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5238 total_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL
);
5239 seq_printf(m
, "total=%lu", total_nr
);
5240 for_each_node_state(nid
, N_MEMORY
) {
5241 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL
);
5242 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5246 file_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_FILE
);
5247 seq_printf(m
, "file=%lu", file_nr
);
5248 for_each_node_state(nid
, N_MEMORY
) {
5249 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5251 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5255 anon_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_ANON
);
5256 seq_printf(m
, "anon=%lu", anon_nr
);
5257 for_each_node_state(nid
, N_MEMORY
) {
5258 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5260 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5264 unevictable_nr
= mem_cgroup_nr_lru_pages(memcg
, BIT(LRU_UNEVICTABLE
));
5265 seq_printf(m
, "unevictable=%lu", unevictable_nr
);
5266 for_each_node_state(nid
, N_MEMORY
) {
5267 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5268 BIT(LRU_UNEVICTABLE
));
5269 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
5274 #endif /* CONFIG_NUMA */
5276 static inline void mem_cgroup_lru_names_not_uptodate(void)
5278 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5281 static int memcg_stat_show(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
5284 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5285 struct mem_cgroup
*mi
;
5288 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5289 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5291 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5292 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5295 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5296 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5297 mem_cgroup_read_events(memcg
, i
));
5299 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5300 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5301 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5303 /* Hierarchical information */
5305 unsigned long long limit
, memsw_limit
;
5306 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5307 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5308 if (do_swap_account
)
5309 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5313 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5316 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5318 for_each_mem_cgroup_tree(mi
, memcg
)
5319 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5320 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5323 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5324 unsigned long long val
= 0;
5326 for_each_mem_cgroup_tree(mi
, memcg
)
5327 val
+= mem_cgroup_read_events(mi
, i
);
5328 seq_printf(m
, "total_%s %llu\n",
5329 mem_cgroup_events_names
[i
], val
);
5332 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5333 unsigned long long val
= 0;
5335 for_each_mem_cgroup_tree(mi
, memcg
)
5336 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5337 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5340 #ifdef CONFIG_DEBUG_VM
5343 struct mem_cgroup_per_zone
*mz
;
5344 struct zone_reclaim_stat
*rstat
;
5345 unsigned long recent_rotated
[2] = {0, 0};
5346 unsigned long recent_scanned
[2] = {0, 0};
5348 for_each_online_node(nid
)
5349 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5350 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5351 rstat
= &mz
->lruvec
.reclaim_stat
;
5353 recent_rotated
[0] += rstat
->recent_rotated
[0];
5354 recent_rotated
[1] += rstat
->recent_rotated
[1];
5355 recent_scanned
[0] += rstat
->recent_scanned
[0];
5356 recent_scanned
[1] += rstat
->recent_scanned
[1];
5358 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5359 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5360 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5361 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5368 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
5371 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5373 return mem_cgroup_swappiness(memcg
);
5376 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
5377 struct cftype
*cft
, u64 val
)
5379 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5380 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5382 if (val
> 100 || !parent
)
5385 mutex_lock(&memcg_create_mutex
);
5387 /* If under hierarchy, only empty-root can set this value */
5388 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5389 mutex_unlock(&memcg_create_mutex
);
5393 memcg
->swappiness
= val
;
5395 mutex_unlock(&memcg_create_mutex
);
5400 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5402 struct mem_cgroup_threshold_ary
*t
;
5408 t
= rcu_dereference(memcg
->thresholds
.primary
);
5410 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5415 usage
= mem_cgroup_usage(memcg
, swap
);
5418 * current_threshold points to threshold just below or equal to usage.
5419 * If it's not true, a threshold was crossed after last
5420 * call of __mem_cgroup_threshold().
5422 i
= t
->current_threshold
;
5425 * Iterate backward over array of thresholds starting from
5426 * current_threshold and check if a threshold is crossed.
5427 * If none of thresholds below usage is crossed, we read
5428 * only one element of the array here.
5430 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5431 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5433 /* i = current_threshold + 1 */
5437 * Iterate forward over array of thresholds starting from
5438 * current_threshold+1 and check if a threshold is crossed.
5439 * If none of thresholds above usage is crossed, we read
5440 * only one element of the array here.
5442 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5443 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5445 /* Update current_threshold */
5446 t
->current_threshold
= i
- 1;
5451 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5454 __mem_cgroup_threshold(memcg
, false);
5455 if (do_swap_account
)
5456 __mem_cgroup_threshold(memcg
, true);
5458 memcg
= parent_mem_cgroup(memcg
);
5462 static int compare_thresholds(const void *a
, const void *b
)
5464 const struct mem_cgroup_threshold
*_a
= a
;
5465 const struct mem_cgroup_threshold
*_b
= b
;
5467 if (_a
->threshold
> _b
->threshold
)
5470 if (_a
->threshold
< _b
->threshold
)
5476 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5478 struct mem_cgroup_eventfd_list
*ev
;
5480 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5481 eventfd_signal(ev
->eventfd
, 1);
5485 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5487 struct mem_cgroup
*iter
;
5489 for_each_mem_cgroup_tree(iter
, memcg
)
5490 mem_cgroup_oom_notify_cb(iter
);
5493 static int mem_cgroup_usage_register_event(struct cgroup_subsys_state
*css
,
5494 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5496 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5497 struct mem_cgroup_thresholds
*thresholds
;
5498 struct mem_cgroup_threshold_ary
*new;
5499 enum res_type type
= MEMFILE_TYPE(cft
->private);
5500 u64 threshold
, usage
;
5503 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5507 mutex_lock(&memcg
->thresholds_lock
);
5510 thresholds
= &memcg
->thresholds
;
5511 else if (type
== _MEMSWAP
)
5512 thresholds
= &memcg
->memsw_thresholds
;
5516 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5518 /* Check if a threshold crossed before adding a new one */
5519 if (thresholds
->primary
)
5520 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5522 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5524 /* Allocate memory for new array of thresholds */
5525 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5533 /* Copy thresholds (if any) to new array */
5534 if (thresholds
->primary
) {
5535 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5536 sizeof(struct mem_cgroup_threshold
));
5539 /* Add new threshold */
5540 new->entries
[size
- 1].eventfd
= eventfd
;
5541 new->entries
[size
- 1].threshold
= threshold
;
5543 /* Sort thresholds. Registering of new threshold isn't time-critical */
5544 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5545 compare_thresholds
, NULL
);
5547 /* Find current threshold */
5548 new->current_threshold
= -1;
5549 for (i
= 0; i
< size
; i
++) {
5550 if (new->entries
[i
].threshold
<= usage
) {
5552 * new->current_threshold will not be used until
5553 * rcu_assign_pointer(), so it's safe to increment
5556 ++new->current_threshold
;
5561 /* Free old spare buffer and save old primary buffer as spare */
5562 kfree(thresholds
->spare
);
5563 thresholds
->spare
= thresholds
->primary
;
5565 rcu_assign_pointer(thresholds
->primary
, new);
5567 /* To be sure that nobody uses thresholds */
5571 mutex_unlock(&memcg
->thresholds_lock
);
5576 static void mem_cgroup_usage_unregister_event(struct cgroup_subsys_state
*css
,
5577 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5579 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5580 struct mem_cgroup_thresholds
*thresholds
;
5581 struct mem_cgroup_threshold_ary
*new;
5582 enum res_type type
= MEMFILE_TYPE(cft
->private);
5586 mutex_lock(&memcg
->thresholds_lock
);
5588 thresholds
= &memcg
->thresholds
;
5589 else if (type
== _MEMSWAP
)
5590 thresholds
= &memcg
->memsw_thresholds
;
5594 if (!thresholds
->primary
)
5597 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5599 /* Check if a threshold crossed before removing */
5600 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5602 /* Calculate new number of threshold */
5604 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5605 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5609 new = thresholds
->spare
;
5611 /* Set thresholds array to NULL if we don't have thresholds */
5620 /* Copy thresholds and find current threshold */
5621 new->current_threshold
= -1;
5622 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5623 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5626 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5627 if (new->entries
[j
].threshold
<= usage
) {
5629 * new->current_threshold will not be used
5630 * until rcu_assign_pointer(), so it's safe to increment
5633 ++new->current_threshold
;
5639 /* Swap primary and spare array */
5640 thresholds
->spare
= thresholds
->primary
;
5641 /* If all events are unregistered, free the spare array */
5643 kfree(thresholds
->spare
);
5644 thresholds
->spare
= NULL
;
5647 rcu_assign_pointer(thresholds
->primary
, new);
5649 /* To be sure that nobody uses thresholds */
5652 mutex_unlock(&memcg
->thresholds_lock
);
5655 static int mem_cgroup_oom_register_event(struct cgroup_subsys_state
*css
,
5656 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
5658 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5659 struct mem_cgroup_eventfd_list
*event
;
5660 enum res_type type
= MEMFILE_TYPE(cft
->private);
5662 BUG_ON(type
!= _OOM_TYPE
);
5663 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5667 spin_lock(&memcg_oom_lock
);
5669 event
->eventfd
= eventfd
;
5670 list_add(&event
->list
, &memcg
->oom_notify
);
5672 /* already in OOM ? */
5673 if (atomic_read(&memcg
->under_oom
))
5674 eventfd_signal(eventfd
, 1);
5675 spin_unlock(&memcg_oom_lock
);
5680 static void mem_cgroup_oom_unregister_event(struct cgroup_subsys_state
*css
,
5681 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
5683 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5684 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5685 enum res_type type
= MEMFILE_TYPE(cft
->private);
5687 BUG_ON(type
!= _OOM_TYPE
);
5689 spin_lock(&memcg_oom_lock
);
5691 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5692 if (ev
->eventfd
== eventfd
) {
5693 list_del(&ev
->list
);
5698 spin_unlock(&memcg_oom_lock
);
5701 static int mem_cgroup_oom_control_read(struct cgroup_subsys_state
*css
,
5702 struct cftype
*cft
, struct cgroup_map_cb
*cb
)
5704 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5706 cb
->fill(cb
, "oom_kill_disable", memcg
->oom_kill_disable
);
5708 if (atomic_read(&memcg
->under_oom
))
5709 cb
->fill(cb
, "under_oom", 1);
5711 cb
->fill(cb
, "under_oom", 0);
5715 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
5716 struct cftype
*cft
, u64 val
)
5718 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5719 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5721 /* cannot set to root cgroup and only 0 and 1 are allowed */
5722 if (!parent
|| !((val
== 0) || (val
== 1)))
5725 mutex_lock(&memcg_create_mutex
);
5726 /* oom-kill-disable is a flag for subhierarchy. */
5727 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5728 mutex_unlock(&memcg_create_mutex
);
5731 memcg
->oom_kill_disable
= val
;
5733 memcg_oom_recover(memcg
);
5734 mutex_unlock(&memcg_create_mutex
);
5738 #ifdef CONFIG_MEMCG_KMEM
5739 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5743 memcg
->kmemcg_id
= -1;
5744 ret
= memcg_propagate_kmem(memcg
);
5748 return mem_cgroup_sockets_init(memcg
, ss
);
5751 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5753 mem_cgroup_sockets_destroy(memcg
);
5756 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5758 if (!memcg_kmem_is_active(memcg
))
5762 * kmem charges can outlive the cgroup. In the case of slab
5763 * pages, for instance, a page contain objects from various
5764 * processes. As we prevent from taking a reference for every
5765 * such allocation we have to be careful when doing uncharge
5766 * (see memcg_uncharge_kmem) and here during offlining.
5768 * The idea is that that only the _last_ uncharge which sees
5769 * the dead memcg will drop the last reference. An additional
5770 * reference is taken here before the group is marked dead
5771 * which is then paired with css_put during uncharge resp. here.
5773 * Although this might sound strange as this path is called from
5774 * css_offline() when the referencemight have dropped down to 0
5775 * and shouldn't be incremented anymore (css_tryget would fail)
5776 * we do not have other options because of the kmem allocations
5779 css_get(&memcg
->css
);
5781 memcg_kmem_mark_dead(memcg
);
5783 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5786 if (memcg_kmem_test_and_clear_dead(memcg
))
5787 css_put(&memcg
->css
);
5790 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5795 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5799 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5804 static struct cftype mem_cgroup_files
[] = {
5806 .name
= "usage_in_bytes",
5807 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
5808 .read
= mem_cgroup_read
,
5809 .register_event
= mem_cgroup_usage_register_event
,
5810 .unregister_event
= mem_cgroup_usage_unregister_event
,
5813 .name
= "max_usage_in_bytes",
5814 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
5815 .trigger
= mem_cgroup_reset
,
5816 .read
= mem_cgroup_read
,
5819 .name
= "limit_in_bytes",
5820 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
5821 .write_string
= mem_cgroup_write
,
5822 .read
= mem_cgroup_read
,
5825 .name
= "soft_limit_in_bytes",
5826 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
5827 .write_string
= mem_cgroup_write
,
5828 .read
= mem_cgroup_read
,
5832 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
5833 .trigger
= mem_cgroup_reset
,
5834 .read
= mem_cgroup_read
,
5838 .read_seq_string
= memcg_stat_show
,
5841 .name
= "force_empty",
5842 .trigger
= mem_cgroup_force_empty_write
,
5845 .name
= "use_hierarchy",
5846 .flags
= CFTYPE_INSANE
,
5847 .write_u64
= mem_cgroup_hierarchy_write
,
5848 .read_u64
= mem_cgroup_hierarchy_read
,
5851 .name
= "swappiness",
5852 .read_u64
= mem_cgroup_swappiness_read
,
5853 .write_u64
= mem_cgroup_swappiness_write
,
5856 .name
= "move_charge_at_immigrate",
5857 .read_u64
= mem_cgroup_move_charge_read
,
5858 .write_u64
= mem_cgroup_move_charge_write
,
5861 .name
= "oom_control",
5862 .read_map
= mem_cgroup_oom_control_read
,
5863 .write_u64
= mem_cgroup_oom_control_write
,
5864 .register_event
= mem_cgroup_oom_register_event
,
5865 .unregister_event
= mem_cgroup_oom_unregister_event
,
5866 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
5869 .name
= "pressure_level",
5870 .register_event
= vmpressure_register_event
,
5871 .unregister_event
= vmpressure_unregister_event
,
5875 .name
= "numa_stat",
5876 .read_seq_string
= memcg_numa_stat_show
,
5879 #ifdef CONFIG_MEMCG_KMEM
5881 .name
= "kmem.limit_in_bytes",
5882 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
5883 .write_string
= mem_cgroup_write
,
5884 .read
= mem_cgroup_read
,
5887 .name
= "kmem.usage_in_bytes",
5888 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
5889 .read
= mem_cgroup_read
,
5892 .name
= "kmem.failcnt",
5893 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
5894 .trigger
= mem_cgroup_reset
,
5895 .read
= mem_cgroup_read
,
5898 .name
= "kmem.max_usage_in_bytes",
5899 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
5900 .trigger
= mem_cgroup_reset
,
5901 .read
= mem_cgroup_read
,
5903 #ifdef CONFIG_SLABINFO
5905 .name
= "kmem.slabinfo",
5906 .read_seq_string
= mem_cgroup_slabinfo_read
,
5910 { }, /* terminate */
5913 #ifdef CONFIG_MEMCG_SWAP
5914 static struct cftype memsw_cgroup_files
[] = {
5916 .name
= "memsw.usage_in_bytes",
5917 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
5918 .read
= mem_cgroup_read
,
5919 .register_event
= mem_cgroup_usage_register_event
,
5920 .unregister_event
= mem_cgroup_usage_unregister_event
,
5923 .name
= "memsw.max_usage_in_bytes",
5924 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
5925 .trigger
= mem_cgroup_reset
,
5926 .read
= mem_cgroup_read
,
5929 .name
= "memsw.limit_in_bytes",
5930 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
5931 .write_string
= mem_cgroup_write
,
5932 .read
= mem_cgroup_read
,
5935 .name
= "memsw.failcnt",
5936 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
5937 .trigger
= mem_cgroup_reset
,
5938 .read
= mem_cgroup_read
,
5940 { }, /* terminate */
5943 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5945 struct mem_cgroup_per_node
*pn
;
5946 struct mem_cgroup_per_zone
*mz
;
5947 int zone
, tmp
= node
;
5949 * This routine is called against possible nodes.
5950 * But it's BUG to call kmalloc() against offline node.
5952 * TODO: this routine can waste much memory for nodes which will
5953 * never be onlined. It's better to use memory hotplug callback
5956 if (!node_state(node
, N_NORMAL_MEMORY
))
5958 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
5962 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
5963 mz
= &pn
->zoneinfo
[zone
];
5964 lruvec_init(&mz
->lruvec
);
5965 mz
->usage_in_excess
= 0;
5966 mz
->on_tree
= false;
5969 memcg
->nodeinfo
[node
] = pn
;
5973 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
5975 kfree(memcg
->nodeinfo
[node
]);
5978 static struct mem_cgroup
*mem_cgroup_alloc(void)
5980 struct mem_cgroup
*memcg
;
5981 size_t size
= memcg_size();
5983 /* Can be very big if nr_node_ids is very big */
5984 if (size
< PAGE_SIZE
)
5985 memcg
= kzalloc(size
, GFP_KERNEL
);
5987 memcg
= vzalloc(size
);
5992 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
5995 spin_lock_init(&memcg
->pcp_counter_lock
);
5999 if (size
< PAGE_SIZE
)
6007 * At destroying mem_cgroup, references from swap_cgroup can remain.
6008 * (scanning all at force_empty is too costly...)
6010 * Instead of clearing all references at force_empty, we remember
6011 * the number of reference from swap_cgroup and free mem_cgroup when
6012 * it goes down to 0.
6014 * Removal of cgroup itself succeeds regardless of refs from swap.
6017 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
6020 size_t size
= memcg_size();
6022 mem_cgroup_remove_from_trees(memcg
);
6023 free_css_id(&mem_cgroup_subsys
, &memcg
->css
);
6026 free_mem_cgroup_per_zone_info(memcg
, node
);
6028 free_percpu(memcg
->stat
);
6031 * We need to make sure that (at least for now), the jump label
6032 * destruction code runs outside of the cgroup lock. This is because
6033 * get_online_cpus(), which is called from the static_branch update,
6034 * can't be called inside the cgroup_lock. cpusets are the ones
6035 * enforcing this dependency, so if they ever change, we might as well.
6037 * schedule_work() will guarantee this happens. Be careful if you need
6038 * to move this code around, and make sure it is outside
6041 disarm_static_keys(memcg
);
6042 if (size
< PAGE_SIZE
)
6049 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6051 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6053 if (!memcg
->res
.parent
)
6055 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6057 EXPORT_SYMBOL(parent_mem_cgroup
);
6059 static void __init
mem_cgroup_soft_limit_tree_init(void)
6061 struct mem_cgroup_tree_per_node
*rtpn
;
6062 struct mem_cgroup_tree_per_zone
*rtpz
;
6063 int tmp
, node
, zone
;
6065 for_each_node(node
) {
6067 if (!node_state(node
, N_NORMAL_MEMORY
))
6069 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
);
6082 static struct cgroup_subsys_state
* __ref
6083 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
6085 struct mem_cgroup
*memcg
;
6086 long error
= -ENOMEM
;
6089 memcg
= mem_cgroup_alloc();
6091 return ERR_PTR(error
);
6094 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6098 if (parent_css
== NULL
) {
6099 root_mem_cgroup
= memcg
;
6100 res_counter_init(&memcg
->res
, NULL
);
6101 res_counter_init(&memcg
->memsw
, NULL
);
6102 res_counter_init(&memcg
->kmem
, NULL
);
6105 memcg
->last_scanned_node
= MAX_NUMNODES
;
6106 INIT_LIST_HEAD(&memcg
->oom_notify
);
6107 memcg
->move_charge_at_immigrate
= 0;
6108 mutex_init(&memcg
->thresholds_lock
);
6109 spin_lock_init(&memcg
->move_lock
);
6110 vmpressure_init(&memcg
->vmpressure
);
6115 __mem_cgroup_free(memcg
);
6116 return ERR_PTR(error
);
6120 mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
6122 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6123 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(css
));
6129 mutex_lock(&memcg_create_mutex
);
6131 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6132 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6133 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6135 if (parent
->use_hierarchy
) {
6136 res_counter_init(&memcg
->res
, &parent
->res
);
6137 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6138 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6141 * No need to take a reference to the parent because cgroup
6142 * core guarantees its existence.
6145 res_counter_init(&memcg
->res
, NULL
);
6146 res_counter_init(&memcg
->memsw
, NULL
);
6147 res_counter_init(&memcg
->kmem
, NULL
);
6149 * Deeper hierachy with use_hierarchy == false doesn't make
6150 * much sense so let cgroup subsystem know about this
6151 * unfortunate state in our controller.
6153 if (parent
!= root_mem_cgroup
)
6154 mem_cgroup_subsys
.broken_hierarchy
= true;
6157 error
= memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
6158 mutex_unlock(&memcg_create_mutex
);
6163 * Announce all parents that a group from their hierarchy is gone.
6165 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup
*memcg
)
6167 struct mem_cgroup
*parent
= memcg
;
6169 while ((parent
= parent_mem_cgroup(parent
)))
6170 mem_cgroup_iter_invalidate(parent
);
6173 * if the root memcg is not hierarchical we have to check it
6176 if (!root_mem_cgroup
->use_hierarchy
)
6177 mem_cgroup_iter_invalidate(root_mem_cgroup
);
6180 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
6182 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6184 kmem_cgroup_css_offline(memcg
);
6186 mem_cgroup_invalidate_reclaim_iterators(memcg
);
6187 mem_cgroup_reparent_charges(memcg
);
6188 mem_cgroup_destroy_all_caches(memcg
);
6189 vmpressure_cleanup(&memcg
->vmpressure
);
6192 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
6194 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6196 memcg_destroy_kmem(memcg
);
6197 __mem_cgroup_free(memcg
);
6201 /* Handlers for move charge at task migration. */
6202 #define PRECHARGE_COUNT_AT_ONCE 256
6203 static int mem_cgroup_do_precharge(unsigned long count
)
6206 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6207 struct mem_cgroup
*memcg
= mc
.to
;
6209 if (mem_cgroup_is_root(memcg
)) {
6210 mc
.precharge
+= count
;
6211 /* we don't need css_get for root */
6214 /* try to charge at once */
6216 struct res_counter
*dummy
;
6218 * "memcg" cannot be under rmdir() because we've already checked
6219 * by cgroup_lock_live_cgroup() that it is not removed and we
6220 * are still under the same cgroup_mutex. So we can postpone
6223 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6225 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6226 PAGE_SIZE
* count
, &dummy
)) {
6227 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6230 mc
.precharge
+= count
;
6234 /* fall back to one by one charge */
6236 if (signal_pending(current
)) {
6240 if (!batch_count
--) {
6241 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6244 ret
= __mem_cgroup_try_charge(NULL
,
6245 GFP_KERNEL
, 1, &memcg
, false);
6247 /* mem_cgroup_clear_mc() will do uncharge later */
6255 * get_mctgt_type - get target type of moving charge
6256 * @vma: the vma the pte to be checked belongs
6257 * @addr: the address corresponding to the pte to be checked
6258 * @ptent: the pte to be checked
6259 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6262 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6263 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6264 * move charge. if @target is not NULL, the page is stored in target->page
6265 * with extra refcnt got(Callers should handle it).
6266 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6267 * target for charge migration. if @target is not NULL, the entry is stored
6270 * Called with pte lock held.
6277 enum mc_target_type
{
6283 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6284 unsigned long addr
, pte_t ptent
)
6286 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6288 if (!page
|| !page_mapped(page
))
6290 if (PageAnon(page
)) {
6291 /* we don't move shared anon */
6294 } else if (!move_file())
6295 /* we ignore mapcount for file pages */
6297 if (!get_page_unless_zero(page
))
6304 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6305 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6307 struct page
*page
= NULL
;
6308 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6310 if (!move_anon() || non_swap_entry(ent
))
6313 * Because lookup_swap_cache() updates some statistics counter,
6314 * we call find_get_page() with swapper_space directly.
6316 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6317 if (do_swap_account
)
6318 entry
->val
= ent
.val
;
6323 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6324 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6330 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6331 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6333 struct page
*page
= NULL
;
6334 struct address_space
*mapping
;
6337 if (!vma
->vm_file
) /* anonymous vma */
6342 mapping
= vma
->vm_file
->f_mapping
;
6343 if (pte_none(ptent
))
6344 pgoff
= linear_page_index(vma
, addr
);
6345 else /* pte_file(ptent) is true */
6346 pgoff
= pte_to_pgoff(ptent
);
6348 /* page is moved even if it's not RSS of this task(page-faulted). */
6349 page
= find_get_page(mapping
, pgoff
);
6352 /* shmem/tmpfs may report page out on swap: account for that too. */
6353 if (radix_tree_exceptional_entry(page
)) {
6354 swp_entry_t swap
= radix_to_swp_entry(page
);
6355 if (do_swap_account
)
6357 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6363 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6364 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6366 struct page
*page
= NULL
;
6367 struct page_cgroup
*pc
;
6368 enum mc_target_type ret
= MC_TARGET_NONE
;
6369 swp_entry_t ent
= { .val
= 0 };
6371 if (pte_present(ptent
))
6372 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6373 else if (is_swap_pte(ptent
))
6374 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6375 else if (pte_none(ptent
) || pte_file(ptent
))
6376 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6378 if (!page
&& !ent
.val
)
6381 pc
= lookup_page_cgroup(page
);
6383 * Do only loose check w/o page_cgroup lock.
6384 * mem_cgroup_move_account() checks the pc is valid or not under
6387 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6388 ret
= MC_TARGET_PAGE
;
6390 target
->page
= page
;
6392 if (!ret
|| !target
)
6395 /* There is a swap entry and a page doesn't exist or isn't charged */
6396 if (ent
.val
&& !ret
&&
6397 css_id(&mc
.from
->css
) == lookup_swap_cgroup_id(ent
)) {
6398 ret
= MC_TARGET_SWAP
;
6405 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6407 * We don't consider swapping or file mapped pages because THP does not
6408 * support them for now.
6409 * Caller should make sure that pmd_trans_huge(pmd) is true.
6411 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6412 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6414 struct page
*page
= NULL
;
6415 struct page_cgroup
*pc
;
6416 enum mc_target_type ret
= MC_TARGET_NONE
;
6418 page
= pmd_page(pmd
);
6419 VM_BUG_ON(!page
|| !PageHead(page
));
6422 pc
= lookup_page_cgroup(page
);
6423 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6424 ret
= MC_TARGET_PAGE
;
6427 target
->page
= page
;
6433 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6434 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6436 return MC_TARGET_NONE
;
6440 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6441 unsigned long addr
, unsigned long end
,
6442 struct mm_walk
*walk
)
6444 struct vm_area_struct
*vma
= walk
->private;
6448 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6449 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6450 mc
.precharge
+= HPAGE_PMD_NR
;
6451 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6455 if (pmd_trans_unstable(pmd
))
6457 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6458 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6459 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6460 mc
.precharge
++; /* increment precharge temporarily */
6461 pte_unmap_unlock(pte
- 1, ptl
);
6467 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6469 unsigned long precharge
;
6470 struct vm_area_struct
*vma
;
6472 down_read(&mm
->mmap_sem
);
6473 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6474 struct mm_walk mem_cgroup_count_precharge_walk
= {
6475 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6479 if (is_vm_hugetlb_page(vma
))
6481 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6482 &mem_cgroup_count_precharge_walk
);
6484 up_read(&mm
->mmap_sem
);
6486 precharge
= mc
.precharge
;
6492 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6494 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6496 VM_BUG_ON(mc
.moving_task
);
6497 mc
.moving_task
= current
;
6498 return mem_cgroup_do_precharge(precharge
);
6501 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6502 static void __mem_cgroup_clear_mc(void)
6504 struct mem_cgroup
*from
= mc
.from
;
6505 struct mem_cgroup
*to
= mc
.to
;
6508 /* we must uncharge all the leftover precharges from mc.to */
6510 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6514 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6515 * we must uncharge here.
6517 if (mc
.moved_charge
) {
6518 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6519 mc
.moved_charge
= 0;
6521 /* we must fixup refcnts and charges */
6522 if (mc
.moved_swap
) {
6523 /* uncharge swap account from the old cgroup */
6524 if (!mem_cgroup_is_root(mc
.from
))
6525 res_counter_uncharge(&mc
.from
->memsw
,
6526 PAGE_SIZE
* mc
.moved_swap
);
6528 for (i
= 0; i
< mc
.moved_swap
; i
++)
6529 css_put(&mc
.from
->css
);
6531 if (!mem_cgroup_is_root(mc
.to
)) {
6533 * we charged both to->res and to->memsw, so we should
6536 res_counter_uncharge(&mc
.to
->res
,
6537 PAGE_SIZE
* mc
.moved_swap
);
6539 /* we've already done css_get(mc.to) */
6542 memcg_oom_recover(from
);
6543 memcg_oom_recover(to
);
6544 wake_up_all(&mc
.waitq
);
6547 static void mem_cgroup_clear_mc(void)
6549 struct mem_cgroup
*from
= mc
.from
;
6552 * we must clear moving_task before waking up waiters at the end of
6555 mc
.moving_task
= NULL
;
6556 __mem_cgroup_clear_mc();
6557 spin_lock(&mc
.lock
);
6560 spin_unlock(&mc
.lock
);
6561 mem_cgroup_end_move(from
);
6564 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
6565 struct cgroup_taskset
*tset
)
6567 struct task_struct
*p
= cgroup_taskset_first(tset
);
6569 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6570 unsigned long move_charge_at_immigrate
;
6573 * We are now commited to this value whatever it is. Changes in this
6574 * tunable will only affect upcoming migrations, not the current one.
6575 * So we need to save it, and keep it going.
6577 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
6578 if (move_charge_at_immigrate
) {
6579 struct mm_struct
*mm
;
6580 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
6582 VM_BUG_ON(from
== memcg
);
6584 mm
= get_task_mm(p
);
6587 /* We move charges only when we move a owner of the mm */
6588 if (mm
->owner
== p
) {
6591 VM_BUG_ON(mc
.precharge
);
6592 VM_BUG_ON(mc
.moved_charge
);
6593 VM_BUG_ON(mc
.moved_swap
);
6594 mem_cgroup_start_move(from
);
6595 spin_lock(&mc
.lock
);
6598 mc
.immigrate_flags
= move_charge_at_immigrate
;
6599 spin_unlock(&mc
.lock
);
6600 /* We set mc.moving_task later */
6602 ret
= mem_cgroup_precharge_mc(mm
);
6604 mem_cgroup_clear_mc();
6611 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
6612 struct cgroup_taskset
*tset
)
6614 mem_cgroup_clear_mc();
6617 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
6618 unsigned long addr
, unsigned long end
,
6619 struct mm_walk
*walk
)
6622 struct vm_area_struct
*vma
= walk
->private;
6625 enum mc_target_type target_type
;
6626 union mc_target target
;
6628 struct page_cgroup
*pc
;
6631 * We don't take compound_lock() here but no race with splitting thp
6633 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
6634 * under splitting, which means there's no concurrent thp split,
6635 * - if another thread runs into split_huge_page() just after we
6636 * entered this if-block, the thread must wait for page table lock
6637 * to be unlocked in __split_huge_page_splitting(), where the main
6638 * part of thp split is not executed yet.
6640 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
6641 if (mc
.precharge
< HPAGE_PMD_NR
) {
6642 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6645 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
6646 if (target_type
== MC_TARGET_PAGE
) {
6648 if (!isolate_lru_page(page
)) {
6649 pc
= lookup_page_cgroup(page
);
6650 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
6651 pc
, mc
.from
, mc
.to
)) {
6652 mc
.precharge
-= HPAGE_PMD_NR
;
6653 mc
.moved_charge
+= HPAGE_PMD_NR
;
6655 putback_lru_page(page
);
6659 spin_unlock(&vma
->vm_mm
->page_table_lock
);
6663 if (pmd_trans_unstable(pmd
))
6666 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6667 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
6668 pte_t ptent
= *(pte
++);
6674 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
6675 case MC_TARGET_PAGE
:
6677 if (isolate_lru_page(page
))
6679 pc
= lookup_page_cgroup(page
);
6680 if (!mem_cgroup_move_account(page
, 1, pc
,
6683 /* we uncharge from mc.from later. */
6686 putback_lru_page(page
);
6687 put
: /* get_mctgt_type() gets the page */
6690 case MC_TARGET_SWAP
:
6692 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
6694 /* we fixup refcnts and charges later. */
6702 pte_unmap_unlock(pte
- 1, ptl
);
6707 * We have consumed all precharges we got in can_attach().
6708 * We try charge one by one, but don't do any additional
6709 * charges to mc.to if we have failed in charge once in attach()
6712 ret
= mem_cgroup_do_precharge(1);
6720 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
6722 struct vm_area_struct
*vma
;
6724 lru_add_drain_all();
6726 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
6728 * Someone who are holding the mmap_sem might be waiting in
6729 * waitq. So we cancel all extra charges, wake up all waiters,
6730 * and retry. Because we cancel precharges, we might not be able
6731 * to move enough charges, but moving charge is a best-effort
6732 * feature anyway, so it wouldn't be a big problem.
6734 __mem_cgroup_clear_mc();
6738 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6740 struct mm_walk mem_cgroup_move_charge_walk
= {
6741 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
6745 if (is_vm_hugetlb_page(vma
))
6747 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
6748 &mem_cgroup_move_charge_walk
);
6751 * means we have consumed all precharges and failed in
6752 * doing additional charge. Just abandon here.
6756 up_read(&mm
->mmap_sem
);
6759 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
6760 struct cgroup_taskset
*tset
)
6762 struct task_struct
*p
= cgroup_taskset_first(tset
);
6763 struct mm_struct
*mm
= get_task_mm(p
);
6767 mem_cgroup_move_charge(mm
);
6771 mem_cgroup_clear_mc();
6773 #else /* !CONFIG_MMU */
6774 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
6775 struct cgroup_taskset
*tset
)
6779 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
6780 struct cgroup_taskset
*tset
)
6783 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
6784 struct cgroup_taskset
*tset
)
6790 * Cgroup retains root cgroups across [un]mount cycles making it necessary
6791 * to verify sane_behavior flag on each mount attempt.
6793 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
6796 * use_hierarchy is forced with sane_behavior. cgroup core
6797 * guarantees that @root doesn't have any children, so turning it
6798 * on for the root memcg is enough.
6800 if (cgroup_sane_behavior(root_css
->cgroup
))
6801 mem_cgroup_from_css(root_css
)->use_hierarchy
= true;
6804 struct cgroup_subsys mem_cgroup_subsys
= {
6806 .subsys_id
= mem_cgroup_subsys_id
,
6807 .css_alloc
= mem_cgroup_css_alloc
,
6808 .css_online
= mem_cgroup_css_online
,
6809 .css_offline
= mem_cgroup_css_offline
,
6810 .css_free
= mem_cgroup_css_free
,
6811 .can_attach
= mem_cgroup_can_attach
,
6812 .cancel_attach
= mem_cgroup_cancel_attach
,
6813 .attach
= mem_cgroup_move_task
,
6814 .bind
= mem_cgroup_bind
,
6815 .base_cftypes
= mem_cgroup_files
,
6820 #ifdef CONFIG_MEMCG_SWAP
6821 static int __init
enable_swap_account(char *s
)
6823 if (!strcmp(s
, "1"))
6824 really_do_swap_account
= 1;
6825 else if (!strcmp(s
, "0"))
6826 really_do_swap_account
= 0;
6829 __setup("swapaccount=", enable_swap_account
);
6831 static void __init
memsw_file_init(void)
6833 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys
, memsw_cgroup_files
));
6836 static void __init
enable_swap_cgroup(void)
6838 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6839 do_swap_account
= 1;
6845 static void __init
enable_swap_cgroup(void)
6851 * subsys_initcall() for memory controller.
6853 * Some parts like hotcpu_notifier() have to be initialized from this context
6854 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
6855 * everything that doesn't depend on a specific mem_cgroup structure should
6856 * be initialized from here.
6858 static int __init
mem_cgroup_init(void)
6860 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
6861 enable_swap_cgroup();
6862 mem_cgroup_soft_limit_tree_init();
6866 subsys_initcall(mem_cgroup_init
);