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/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/page_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
62 #include <net/tcp_memcontrol.h>
65 #include <asm/uaccess.h>
67 #include <trace/events/vmscan.h>
69 struct cgroup_subsys mem_cgroup_subsys __read_mostly
;
70 EXPORT_SYMBOL(mem_cgroup_subsys
);
72 #define MEM_CGROUP_RECLAIM_RETRIES 5
73 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
75 #ifdef CONFIG_MEMCG_SWAP
76 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
77 int do_swap_account __read_mostly
;
79 /* for remember boot option*/
80 #ifdef CONFIG_MEMCG_SWAP_ENABLED
81 static int really_do_swap_account __initdata
= 1;
83 static int really_do_swap_account __initdata
= 0;
87 #define do_swap_account 0
91 static const char * const mem_cgroup_stat_names
[] = {
100 enum mem_cgroup_events_index
{
101 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
102 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
103 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
104 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
105 MEM_CGROUP_EVENTS_NSTATS
,
108 static const char * const mem_cgroup_events_names
[] = {
115 static const char * const mem_cgroup_lru_names
[] = {
124 * Per memcg event counter is incremented at every pagein/pageout. With THP,
125 * it will be incremated by the number of pages. This counter is used for
126 * for trigger some periodic events. This is straightforward and better
127 * than using jiffies etc. to handle periodic memcg event.
129 enum mem_cgroup_events_target
{
130 MEM_CGROUP_TARGET_THRESH
,
131 MEM_CGROUP_TARGET_SOFTLIMIT
,
132 MEM_CGROUP_TARGET_NUMAINFO
,
135 #define THRESHOLDS_EVENTS_TARGET 128
136 #define SOFTLIMIT_EVENTS_TARGET 1024
137 #define NUMAINFO_EVENTS_TARGET 1024
139 struct mem_cgroup_stat_cpu
{
140 long count
[MEM_CGROUP_STAT_NSTATS
];
141 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
142 unsigned long nr_page_events
;
143 unsigned long targets
[MEM_CGROUP_NTARGETS
];
146 struct mem_cgroup_reclaim_iter
{
148 * last scanned hierarchy member. Valid only if last_dead_count
149 * matches memcg->dead_count of the hierarchy root group.
151 struct mem_cgroup
*last_visited
;
154 /* scan generation, increased every round-trip */
155 unsigned int generation
;
159 * per-zone information in memory controller.
161 struct mem_cgroup_per_zone
{
162 struct lruvec lruvec
;
163 unsigned long lru_size
[NR_LRU_LISTS
];
165 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
167 struct rb_node tree_node
; /* RB tree node */
168 unsigned long long usage_in_excess
;/* Set to the value by which */
169 /* the soft limit is exceeded*/
171 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
172 /* use container_of */
175 struct mem_cgroup_per_node
{
176 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
180 * Cgroups above their limits are maintained in a RB-Tree, independent of
181 * their hierarchy representation
184 struct mem_cgroup_tree_per_zone
{
185 struct rb_root rb_root
;
189 struct mem_cgroup_tree_per_node
{
190 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
193 struct mem_cgroup_tree
{
194 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
197 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
199 struct mem_cgroup_threshold
{
200 struct eventfd_ctx
*eventfd
;
205 struct mem_cgroup_threshold_ary
{
206 /* An array index points to threshold just below or equal to usage. */
207 int current_threshold
;
208 /* Size of entries[] */
210 /* Array of thresholds */
211 struct mem_cgroup_threshold entries
[0];
214 struct mem_cgroup_thresholds
{
215 /* Primary thresholds array */
216 struct mem_cgroup_threshold_ary
*primary
;
218 * Spare threshold array.
219 * This is needed to make mem_cgroup_unregister_event() "never fail".
220 * It must be able to store at least primary->size - 1 entries.
222 struct mem_cgroup_threshold_ary
*spare
;
226 struct mem_cgroup_eventfd_list
{
227 struct list_head list
;
228 struct eventfd_ctx
*eventfd
;
232 * cgroup_event represents events which userspace want to receive.
234 struct mem_cgroup_event
{
236 * memcg which the event belongs to.
238 struct mem_cgroup
*memcg
;
240 * eventfd to signal userspace about the event.
242 struct eventfd_ctx
*eventfd
;
244 * Each of these stored in a list by the cgroup.
246 struct list_head list
;
248 * register_event() callback will be used to add new userspace
249 * waiter for changes related to this event. Use eventfd_signal()
250 * on eventfd to send notification to userspace.
252 int (*register_event
)(struct mem_cgroup
*memcg
,
253 struct eventfd_ctx
*eventfd
, const char *args
);
255 * unregister_event() callback will be called when userspace closes
256 * the eventfd or on cgroup removing. This callback must be set,
257 * if you want provide notification functionality.
259 void (*unregister_event
)(struct mem_cgroup
*memcg
,
260 struct eventfd_ctx
*eventfd
);
262 * All fields below needed to unregister event when
263 * userspace closes eventfd.
266 wait_queue_head_t
*wqh
;
268 struct work_struct remove
;
271 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
272 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
275 * The memory controller data structure. The memory controller controls both
276 * page cache and RSS per cgroup. We would eventually like to provide
277 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
278 * to help the administrator determine what knobs to tune.
280 * TODO: Add a water mark for the memory controller. Reclaim will begin when
281 * we hit the water mark. May be even add a low water mark, such that
282 * no reclaim occurs from a cgroup at it's low water mark, this is
283 * a feature that will be implemented much later in the future.
286 struct cgroup_subsys_state css
;
288 * the counter to account for memory usage
290 struct res_counter res
;
292 /* vmpressure notifications */
293 struct vmpressure vmpressure
;
296 * the counter to account for mem+swap usage.
298 struct res_counter memsw
;
301 * the counter to account for kernel memory usage.
303 struct res_counter kmem
;
305 * Should the accounting and control be hierarchical, per subtree?
308 unsigned long kmem_account_flags
; /* See KMEM_ACCOUNTED_*, below */
312 atomic_t oom_wakeups
;
315 /* OOM-Killer disable */
316 int oom_kill_disable
;
318 /* set when res.limit == memsw.limit */
319 bool memsw_is_minimum
;
321 /* protect arrays of thresholds */
322 struct mutex thresholds_lock
;
324 /* thresholds for memory usage. RCU-protected */
325 struct mem_cgroup_thresholds thresholds
;
327 /* thresholds for mem+swap usage. RCU-protected */
328 struct mem_cgroup_thresholds memsw_thresholds
;
330 /* For oom notifier event fd */
331 struct list_head oom_notify
;
334 * Should we move charges of a task when a task is moved into this
335 * mem_cgroup ? And what type of charges should we move ?
337 unsigned long move_charge_at_immigrate
;
339 * set > 0 if pages under this cgroup are moving to other cgroup.
341 atomic_t moving_account
;
342 /* taken only while moving_account > 0 */
343 spinlock_t move_lock
;
347 struct mem_cgroup_stat_cpu __percpu
*stat
;
349 * used when a cpu is offlined or other synchronizations
350 * See mem_cgroup_read_stat().
352 struct mem_cgroup_stat_cpu nocpu_base
;
353 spinlock_t pcp_counter_lock
;
356 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
357 struct cg_proto tcp_mem
;
359 #if defined(CONFIG_MEMCG_KMEM)
360 /* analogous to slab_common's slab_caches list. per-memcg */
361 struct list_head memcg_slab_caches
;
362 /* Not a spinlock, we can take a lot of time walking the list */
363 struct mutex slab_caches_mutex
;
364 /* Index in the kmem_cache->memcg_params->memcg_caches array */
368 int last_scanned_node
;
370 nodemask_t scan_nodes
;
371 atomic_t numainfo_events
;
372 atomic_t numainfo_updating
;
375 /* List of events which userspace want to receive */
376 struct list_head event_list
;
377 spinlock_t event_list_lock
;
379 struct mem_cgroup_per_node
*nodeinfo
[0];
380 /* WARNING: nodeinfo must be the last member here */
383 /* internal only representation about the status of kmem accounting. */
385 KMEM_ACCOUNTED_ACTIVE
, /* accounted by this cgroup itself */
386 KMEM_ACCOUNTED_DEAD
, /* dead memcg with pending kmem charges */
389 #ifdef CONFIG_MEMCG_KMEM
390 static inline void memcg_kmem_set_active(struct mem_cgroup
*memcg
)
392 set_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
395 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
397 return test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
400 static void memcg_kmem_mark_dead(struct mem_cgroup
*memcg
)
403 * Our caller must use css_get() first, because memcg_uncharge_kmem()
404 * will call css_put() if it sees the memcg is dead.
407 if (test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
))
408 set_bit(KMEM_ACCOUNTED_DEAD
, &memcg
->kmem_account_flags
);
411 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup
*memcg
)
413 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD
,
414 &memcg
->kmem_account_flags
);
418 /* Stuffs for move charges at task migration. */
420 * Types of charges to be moved. "move_charge_at_immitgrate" and
421 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
424 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
425 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
429 /* "mc" and its members are protected by cgroup_mutex */
430 static struct move_charge_struct
{
431 spinlock_t lock
; /* for from, to */
432 struct mem_cgroup
*from
;
433 struct mem_cgroup
*to
;
434 unsigned long immigrate_flags
;
435 unsigned long precharge
;
436 unsigned long moved_charge
;
437 unsigned long moved_swap
;
438 struct task_struct
*moving_task
; /* a task moving charges */
439 wait_queue_head_t waitq
; /* a waitq for other context */
441 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
442 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
445 static bool move_anon(void)
447 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
450 static bool move_file(void)
452 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
456 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
457 * limit reclaim to prevent infinite loops, if they ever occur.
459 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
460 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
463 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
464 MEM_CGROUP_CHARGE_TYPE_ANON
,
465 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
466 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
470 /* for encoding cft->private value on file */
478 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
479 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
480 #define MEMFILE_ATTR(val) ((val) & 0xffff)
481 /* Used for OOM nofiier */
482 #define OOM_CONTROL (0)
485 * Reclaim flags for mem_cgroup_hierarchical_reclaim
487 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
488 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
489 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
490 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
493 * The memcg_create_mutex will be held whenever a new cgroup is created.
494 * As a consequence, any change that needs to protect against new child cgroups
495 * appearing has to hold it as well.
497 static DEFINE_MUTEX(memcg_create_mutex
);
499 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
501 return s
? container_of(s
, struct mem_cgroup
, css
) : NULL
;
504 /* Some nice accessors for the vmpressure. */
505 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
508 memcg
= root_mem_cgroup
;
509 return &memcg
->vmpressure
;
512 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
514 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
517 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
519 return (memcg
== root_mem_cgroup
);
523 * We restrict the id in the range of [1, 65535], so it can fit into
526 #define MEM_CGROUP_ID_MAX USHRT_MAX
528 static inline unsigned short mem_cgroup_id(struct mem_cgroup
*memcg
)
531 * The ID of the root cgroup is 0, but memcg treat 0 as an
532 * invalid ID, so we return (cgroup_id + 1).
534 return memcg
->css
.cgroup
->id
+ 1;
537 static inline struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
539 struct cgroup_subsys_state
*css
;
541 css
= css_from_id(id
- 1, &mem_cgroup_subsys
);
542 return mem_cgroup_from_css(css
);
545 /* Writing them here to avoid exposing memcg's inner layout */
546 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
548 void sock_update_memcg(struct sock
*sk
)
550 if (mem_cgroup_sockets_enabled
) {
551 struct mem_cgroup
*memcg
;
552 struct cg_proto
*cg_proto
;
554 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
556 /* Socket cloning can throw us here with sk_cgrp already
557 * filled. It won't however, necessarily happen from
558 * process context. So the test for root memcg given
559 * the current task's memcg won't help us in this case.
561 * Respecting the original socket's memcg is a better
562 * decision in this case.
565 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
566 css_get(&sk
->sk_cgrp
->memcg
->css
);
571 memcg
= mem_cgroup_from_task(current
);
572 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
573 if (!mem_cgroup_is_root(memcg
) &&
574 memcg_proto_active(cg_proto
) && css_tryget(&memcg
->css
)) {
575 sk
->sk_cgrp
= cg_proto
;
580 EXPORT_SYMBOL(sock_update_memcg
);
582 void sock_release_memcg(struct sock
*sk
)
584 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
585 struct mem_cgroup
*memcg
;
586 WARN_ON(!sk
->sk_cgrp
->memcg
);
587 memcg
= sk
->sk_cgrp
->memcg
;
588 css_put(&sk
->sk_cgrp
->memcg
->css
);
592 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
594 if (!memcg
|| mem_cgroup_is_root(memcg
))
597 return &memcg
->tcp_mem
;
599 EXPORT_SYMBOL(tcp_proto_cgroup
);
601 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
603 if (!memcg_proto_activated(&memcg
->tcp_mem
))
605 static_key_slow_dec(&memcg_socket_limit_enabled
);
608 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
613 #ifdef CONFIG_MEMCG_KMEM
615 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
616 * The main reason for not using cgroup id for this:
617 * this works better in sparse environments, where we have a lot of memcgs,
618 * but only a few kmem-limited. Or also, if we have, for instance, 200
619 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
620 * 200 entry array for that.
622 * The current size of the caches array is stored in
623 * memcg_limited_groups_array_size. It will double each time we have to
626 static DEFINE_IDA(kmem_limited_groups
);
627 int memcg_limited_groups_array_size
;
630 * MIN_SIZE is different than 1, because we would like to avoid going through
631 * the alloc/free process all the time. In a small machine, 4 kmem-limited
632 * cgroups is a reasonable guess. In the future, it could be a parameter or
633 * tunable, but that is strictly not necessary.
635 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
636 * this constant directly from cgroup, but it is understandable that this is
637 * better kept as an internal representation in cgroup.c. In any case, the
638 * cgrp_id space is not getting any smaller, and we don't have to necessarily
639 * increase ours as well if it increases.
641 #define MEMCG_CACHES_MIN_SIZE 4
642 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
645 * A lot of the calls to the cache allocation functions are expected to be
646 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
647 * conditional to this static branch, we'll have to allow modules that does
648 * kmem_cache_alloc and the such to see this symbol as well
650 struct static_key memcg_kmem_enabled_key
;
651 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
653 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
655 if (memcg_kmem_is_active(memcg
)) {
656 static_key_slow_dec(&memcg_kmem_enabled_key
);
657 ida_simple_remove(&kmem_limited_groups
, memcg
->kmemcg_id
);
660 * This check can't live in kmem destruction function,
661 * since the charges will outlive the cgroup
663 WARN_ON(res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0);
666 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
669 #endif /* CONFIG_MEMCG_KMEM */
671 static void disarm_static_keys(struct mem_cgroup
*memcg
)
673 disarm_sock_keys(memcg
);
674 disarm_kmem_keys(memcg
);
677 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
679 static struct mem_cgroup_per_zone
*
680 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
682 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
683 return &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
686 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
691 static struct mem_cgroup_per_zone
*
692 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
694 int nid
= page_to_nid(page
);
695 int zid
= page_zonenum(page
);
697 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
700 static struct mem_cgroup_tree_per_zone
*
701 soft_limit_tree_node_zone(int nid
, int zid
)
703 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
706 static struct mem_cgroup_tree_per_zone
*
707 soft_limit_tree_from_page(struct page
*page
)
709 int nid
= page_to_nid(page
);
710 int zid
= page_zonenum(page
);
712 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
716 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
717 struct mem_cgroup_per_zone
*mz
,
718 struct mem_cgroup_tree_per_zone
*mctz
,
719 unsigned long long new_usage_in_excess
)
721 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
722 struct rb_node
*parent
= NULL
;
723 struct mem_cgroup_per_zone
*mz_node
;
728 mz
->usage_in_excess
= new_usage_in_excess
;
729 if (!mz
->usage_in_excess
)
733 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
735 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
738 * We can't avoid mem cgroups that are over their soft
739 * limit by the same amount
741 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
744 rb_link_node(&mz
->tree_node
, parent
, p
);
745 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
750 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
751 struct mem_cgroup_per_zone
*mz
,
752 struct mem_cgroup_tree_per_zone
*mctz
)
756 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
761 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
762 struct mem_cgroup_per_zone
*mz
,
763 struct mem_cgroup_tree_per_zone
*mctz
)
765 spin_lock(&mctz
->lock
);
766 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
767 spin_unlock(&mctz
->lock
);
771 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
773 unsigned long long excess
;
774 struct mem_cgroup_per_zone
*mz
;
775 struct mem_cgroup_tree_per_zone
*mctz
;
776 int nid
= page_to_nid(page
);
777 int zid
= page_zonenum(page
);
778 mctz
= soft_limit_tree_from_page(page
);
781 * Necessary to update all ancestors when hierarchy is used.
782 * because their event counter is not touched.
784 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
785 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
786 excess
= res_counter_soft_limit_excess(&memcg
->res
);
788 * We have to update the tree if mz is on RB-tree or
789 * mem is over its softlimit.
791 if (excess
|| mz
->on_tree
) {
792 spin_lock(&mctz
->lock
);
793 /* if on-tree, remove it */
795 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
797 * Insert again. mz->usage_in_excess will be updated.
798 * If excess is 0, no tree ops.
800 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
801 spin_unlock(&mctz
->lock
);
806 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
809 struct mem_cgroup_per_zone
*mz
;
810 struct mem_cgroup_tree_per_zone
*mctz
;
812 for_each_node(node
) {
813 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
814 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
815 mctz
= soft_limit_tree_node_zone(node
, zone
);
816 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
821 static struct mem_cgroup_per_zone
*
822 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
824 struct rb_node
*rightmost
= NULL
;
825 struct mem_cgroup_per_zone
*mz
;
829 rightmost
= rb_last(&mctz
->rb_root
);
831 goto done
; /* Nothing to reclaim from */
833 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
835 * Remove the node now but someone else can add it back,
836 * we will to add it back at the end of reclaim to its correct
837 * position in the tree.
839 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
840 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
841 !css_tryget(&mz
->memcg
->css
))
847 static struct mem_cgroup_per_zone
*
848 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
850 struct mem_cgroup_per_zone
*mz
;
852 spin_lock(&mctz
->lock
);
853 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
854 spin_unlock(&mctz
->lock
);
859 * Implementation Note: reading percpu statistics for memcg.
861 * Both of vmstat[] and percpu_counter has threshold and do periodic
862 * synchronization to implement "quick" read. There are trade-off between
863 * reading cost and precision of value. Then, we may have a chance to implement
864 * a periodic synchronizion of counter in memcg's counter.
866 * But this _read() function is used for user interface now. The user accounts
867 * memory usage by memory cgroup and he _always_ requires exact value because
868 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
869 * have to visit all online cpus and make sum. So, for now, unnecessary
870 * synchronization is not implemented. (just implemented for cpu hotplug)
872 * If there are kernel internal actions which can make use of some not-exact
873 * value, and reading all cpu value can be performance bottleneck in some
874 * common workload, threashold and synchonization as vmstat[] should be
877 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
878 enum mem_cgroup_stat_index idx
)
884 for_each_online_cpu(cpu
)
885 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
886 #ifdef CONFIG_HOTPLUG_CPU
887 spin_lock(&memcg
->pcp_counter_lock
);
888 val
+= memcg
->nocpu_base
.count
[idx
];
889 spin_unlock(&memcg
->pcp_counter_lock
);
895 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
898 int val
= (charge
) ? 1 : -1;
899 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
902 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
903 enum mem_cgroup_events_index idx
)
905 unsigned long val
= 0;
909 for_each_online_cpu(cpu
)
910 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
911 #ifdef CONFIG_HOTPLUG_CPU
912 spin_lock(&memcg
->pcp_counter_lock
);
913 val
+= memcg
->nocpu_base
.events
[idx
];
914 spin_unlock(&memcg
->pcp_counter_lock
);
920 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
922 bool anon
, int nr_pages
)
927 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
928 * counted as CACHE even if it's on ANON LRU.
931 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
934 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
937 if (PageTransHuge(page
))
938 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
941 /* pagein of a big page is an event. So, ignore page size */
943 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
945 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
946 nr_pages
= -nr_pages
; /* for event */
949 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
955 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
957 struct mem_cgroup_per_zone
*mz
;
959 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
960 return mz
->lru_size
[lru
];
964 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
965 unsigned int lru_mask
)
967 struct mem_cgroup_per_zone
*mz
;
969 unsigned long ret
= 0;
971 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
974 if (BIT(lru
) & lru_mask
)
975 ret
+= mz
->lru_size
[lru
];
981 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
982 int nid
, unsigned int lru_mask
)
987 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
988 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
994 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
995 unsigned int lru_mask
)
1000 for_each_node_state(nid
, N_MEMORY
)
1001 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
1005 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
1006 enum mem_cgroup_events_target target
)
1008 unsigned long val
, next
;
1010 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
1011 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
1012 /* from time_after() in jiffies.h */
1013 if ((long)next
- (long)val
< 0) {
1015 case MEM_CGROUP_TARGET_THRESH
:
1016 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
1018 case MEM_CGROUP_TARGET_SOFTLIMIT
:
1019 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
1021 case MEM_CGROUP_TARGET_NUMAINFO
:
1022 next
= val
+ NUMAINFO_EVENTS_TARGET
;
1027 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
1034 * Check events in order.
1037 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
1040 /* threshold event is triggered in finer grain than soft limit */
1041 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1042 MEM_CGROUP_TARGET_THRESH
))) {
1044 bool do_numainfo __maybe_unused
;
1046 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1047 MEM_CGROUP_TARGET_SOFTLIMIT
);
1048 #if MAX_NUMNODES > 1
1049 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1050 MEM_CGROUP_TARGET_NUMAINFO
);
1054 mem_cgroup_threshold(memcg
);
1055 if (unlikely(do_softlimit
))
1056 mem_cgroup_update_tree(memcg
, page
);
1057 #if MAX_NUMNODES > 1
1058 if (unlikely(do_numainfo
))
1059 atomic_inc(&memcg
->numainfo_events
);
1065 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1068 * mm_update_next_owner() may clear mm->owner to NULL
1069 * if it races with swapoff, page migration, etc.
1070 * So this can be called with p == NULL.
1075 return mem_cgroup_from_css(task_css(p
, mem_cgroup_subsys_id
));
1078 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1080 struct mem_cgroup
*memcg
= NULL
;
1085 * Because we have no locks, mm->owner's may be being moved to other
1086 * cgroup. We use css_tryget() here even if this looks
1087 * pessimistic (rather than adding locks here).
1091 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1092 if (unlikely(!memcg
))
1094 } while (!css_tryget(&memcg
->css
));
1100 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1101 * ref. count) or NULL if the whole root's subtree has been visited.
1103 * helper function to be used by mem_cgroup_iter
1105 static struct mem_cgroup
*__mem_cgroup_iter_next(struct mem_cgroup
*root
,
1106 struct mem_cgroup
*last_visited
)
1108 struct cgroup_subsys_state
*prev_css
, *next_css
;
1110 prev_css
= last_visited
? &last_visited
->css
: NULL
;
1112 next_css
= css_next_descendant_pre(prev_css
, &root
->css
);
1115 * Even if we found a group we have to make sure it is
1116 * alive. css && !memcg means that the groups should be
1117 * skipped and we should continue the tree walk.
1118 * last_visited css is safe to use because it is
1119 * protected by css_get and the tree walk is rcu safe.
1122 if ((next_css
->flags
& CSS_ONLINE
) && css_tryget(next_css
))
1123 return mem_cgroup_from_css(next_css
);
1125 prev_css
= next_css
;
1133 static void mem_cgroup_iter_invalidate(struct mem_cgroup
*root
)
1136 * When a group in the hierarchy below root is destroyed, the
1137 * hierarchy iterator can no longer be trusted since it might
1138 * have pointed to the destroyed group. Invalidate it.
1140 atomic_inc(&root
->dead_count
);
1143 static struct mem_cgroup
*
1144 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter
*iter
,
1145 struct mem_cgroup
*root
,
1148 struct mem_cgroup
*position
= NULL
;
1150 * A cgroup destruction happens in two stages: offlining and
1151 * release. They are separated by a RCU grace period.
1153 * If the iterator is valid, we may still race with an
1154 * offlining. The RCU lock ensures the object won't be
1155 * released, tryget will fail if we lost the race.
1157 *sequence
= atomic_read(&root
->dead_count
);
1158 if (iter
->last_dead_count
== *sequence
) {
1160 position
= iter
->last_visited
;
1161 if (position
&& !css_tryget(&position
->css
))
1167 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter
*iter
,
1168 struct mem_cgroup
*last_visited
,
1169 struct mem_cgroup
*new_position
,
1173 css_put(&last_visited
->css
);
1175 * We store the sequence count from the time @last_visited was
1176 * loaded successfully instead of rereading it here so that we
1177 * don't lose destruction events in between. We could have
1178 * raced with the destruction of @new_position after all.
1180 iter
->last_visited
= new_position
;
1182 iter
->last_dead_count
= sequence
;
1186 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1187 * @root: hierarchy root
1188 * @prev: previously returned memcg, NULL on first invocation
1189 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1191 * Returns references to children of the hierarchy below @root, or
1192 * @root itself, or %NULL after a full round-trip.
1194 * Caller must pass the return value in @prev on subsequent
1195 * invocations for reference counting, or use mem_cgroup_iter_break()
1196 * to cancel a hierarchy walk before the round-trip is complete.
1198 * Reclaimers can specify a zone and a priority level in @reclaim to
1199 * divide up the memcgs in the hierarchy among all concurrent
1200 * reclaimers operating on the same zone and priority.
1202 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1203 struct mem_cgroup
*prev
,
1204 struct mem_cgroup_reclaim_cookie
*reclaim
)
1206 struct mem_cgroup
*memcg
= NULL
;
1207 struct mem_cgroup
*last_visited
= NULL
;
1209 if (mem_cgroup_disabled())
1213 root
= root_mem_cgroup
;
1215 if (prev
&& !reclaim
)
1216 last_visited
= prev
;
1218 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1226 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1227 int uninitialized_var(seq
);
1230 int nid
= zone_to_nid(reclaim
->zone
);
1231 int zid
= zone_idx(reclaim
->zone
);
1232 struct mem_cgroup_per_zone
*mz
;
1234 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1235 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1236 if (prev
&& reclaim
->generation
!= iter
->generation
) {
1237 iter
->last_visited
= NULL
;
1241 last_visited
= mem_cgroup_iter_load(iter
, root
, &seq
);
1244 memcg
= __mem_cgroup_iter_next(root
, last_visited
);
1247 mem_cgroup_iter_update(iter
, last_visited
, memcg
, seq
);
1251 else if (!prev
&& memcg
)
1252 reclaim
->generation
= iter
->generation
;
1261 if (prev
&& prev
!= root
)
1262 css_put(&prev
->css
);
1268 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1269 * @root: hierarchy root
1270 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1272 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1273 struct mem_cgroup
*prev
)
1276 root
= root_mem_cgroup
;
1277 if (prev
&& prev
!= root
)
1278 css_put(&prev
->css
);
1282 * Iteration constructs for visiting all cgroups (under a tree). If
1283 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1284 * be used for reference counting.
1286 #define for_each_mem_cgroup_tree(iter, root) \
1287 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1289 iter = mem_cgroup_iter(root, iter, NULL))
1291 #define for_each_mem_cgroup(iter) \
1292 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1294 iter = mem_cgroup_iter(NULL, iter, NULL))
1296 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1298 struct mem_cgroup
*memcg
;
1301 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1302 if (unlikely(!memcg
))
1307 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1310 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1318 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1321 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1322 * @zone: zone of the wanted lruvec
1323 * @memcg: memcg of the wanted lruvec
1325 * Returns the lru list vector holding pages for the given @zone and
1326 * @mem. This can be the global zone lruvec, if the memory controller
1329 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1330 struct mem_cgroup
*memcg
)
1332 struct mem_cgroup_per_zone
*mz
;
1333 struct lruvec
*lruvec
;
1335 if (mem_cgroup_disabled()) {
1336 lruvec
= &zone
->lruvec
;
1340 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1341 lruvec
= &mz
->lruvec
;
1344 * Since a node can be onlined after the mem_cgroup was created,
1345 * we have to be prepared to initialize lruvec->zone here;
1346 * and if offlined then reonlined, we need to reinitialize it.
1348 if (unlikely(lruvec
->zone
!= zone
))
1349 lruvec
->zone
= zone
;
1354 * Following LRU functions are allowed to be used without PCG_LOCK.
1355 * Operations are called by routine of global LRU independently from memcg.
1356 * What we have to take care of here is validness of pc->mem_cgroup.
1358 * Changes to pc->mem_cgroup happens when
1361 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1362 * It is added to LRU before charge.
1363 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1364 * When moving account, the page is not on LRU. It's isolated.
1368 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1370 * @zone: zone of the page
1372 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1374 struct mem_cgroup_per_zone
*mz
;
1375 struct mem_cgroup
*memcg
;
1376 struct page_cgroup
*pc
;
1377 struct lruvec
*lruvec
;
1379 if (mem_cgroup_disabled()) {
1380 lruvec
= &zone
->lruvec
;
1384 pc
= lookup_page_cgroup(page
);
1385 memcg
= pc
->mem_cgroup
;
1388 * Surreptitiously switch any uncharged offlist page to root:
1389 * an uncharged page off lru does nothing to secure
1390 * its former mem_cgroup from sudden removal.
1392 * Our caller holds lru_lock, and PageCgroupUsed is updated
1393 * under page_cgroup lock: between them, they make all uses
1394 * of pc->mem_cgroup safe.
1396 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1397 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1399 mz
= page_cgroup_zoneinfo(memcg
, page
);
1400 lruvec
= &mz
->lruvec
;
1403 * Since a node can be onlined after the mem_cgroup was created,
1404 * we have to be prepared to initialize lruvec->zone here;
1405 * and if offlined then reonlined, we need to reinitialize it.
1407 if (unlikely(lruvec
->zone
!= zone
))
1408 lruvec
->zone
= zone
;
1413 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1414 * @lruvec: mem_cgroup per zone lru vector
1415 * @lru: index of lru list the page is sitting on
1416 * @nr_pages: positive when adding or negative when removing
1418 * This function must be called when a page is added to or removed from an
1421 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1424 struct mem_cgroup_per_zone
*mz
;
1425 unsigned long *lru_size
;
1427 if (mem_cgroup_disabled())
1430 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1431 lru_size
= mz
->lru_size
+ lru
;
1432 *lru_size
+= nr_pages
;
1433 VM_BUG_ON((long)(*lru_size
) < 0);
1437 * Checks whether given mem is same or in the root_mem_cgroup's
1440 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1441 struct mem_cgroup
*memcg
)
1443 if (root_memcg
== memcg
)
1445 if (!root_memcg
->use_hierarchy
|| !memcg
)
1447 return cgroup_is_descendant(memcg
->css
.cgroup
, root_memcg
->css
.cgroup
);
1450 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1451 struct mem_cgroup
*memcg
)
1456 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1461 bool task_in_mem_cgroup(struct task_struct
*task
,
1462 const struct mem_cgroup
*memcg
)
1464 struct mem_cgroup
*curr
= NULL
;
1465 struct task_struct
*p
;
1468 p
= find_lock_task_mm(task
);
1470 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1474 * All threads may have already detached their mm's, but the oom
1475 * killer still needs to detect if they have already been oom
1476 * killed to prevent needlessly killing additional tasks.
1479 curr
= mem_cgroup_from_task(task
);
1481 css_get(&curr
->css
);
1487 * We should check use_hierarchy of "memcg" not "curr". Because checking
1488 * use_hierarchy of "curr" here make this function true if hierarchy is
1489 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1490 * hierarchy(even if use_hierarchy is disabled in "memcg").
1492 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1493 css_put(&curr
->css
);
1497 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1499 unsigned long inactive_ratio
;
1500 unsigned long inactive
;
1501 unsigned long active
;
1504 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1505 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1507 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1509 inactive_ratio
= int_sqrt(10 * gb
);
1513 return inactive
* inactive_ratio
< active
;
1516 #define mem_cgroup_from_res_counter(counter, member) \
1517 container_of(counter, struct mem_cgroup, member)
1520 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1521 * @memcg: the memory cgroup
1523 * Returns the maximum amount of memory @mem can be charged with, in
1526 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1528 unsigned long long margin
;
1530 margin
= res_counter_margin(&memcg
->res
);
1531 if (do_swap_account
)
1532 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1533 return margin
>> PAGE_SHIFT
;
1536 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1539 if (!css_parent(&memcg
->css
))
1540 return vm_swappiness
;
1542 return memcg
->swappiness
;
1546 * memcg->moving_account is used for checking possibility that some thread is
1547 * calling move_account(). When a thread on CPU-A starts moving pages under
1548 * a memcg, other threads should check memcg->moving_account under
1549 * rcu_read_lock(), like this:
1553 * memcg->moving_account+1 if (memcg->mocing_account)
1555 * synchronize_rcu() update something.
1560 /* for quick checking without looking up memcg */
1561 atomic_t memcg_moving __read_mostly
;
1563 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1565 atomic_inc(&memcg_moving
);
1566 atomic_inc(&memcg
->moving_account
);
1570 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1573 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1574 * We check NULL in callee rather than caller.
1577 atomic_dec(&memcg_moving
);
1578 atomic_dec(&memcg
->moving_account
);
1583 * 2 routines for checking "mem" is under move_account() or not.
1585 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1586 * is used for avoiding races in accounting. If true,
1587 * pc->mem_cgroup may be overwritten.
1589 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1590 * under hierarchy of moving cgroups. This is for
1591 * waiting at hith-memory prressure caused by "move".
1594 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1596 VM_BUG_ON(!rcu_read_lock_held());
1597 return atomic_read(&memcg
->moving_account
) > 0;
1600 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1602 struct mem_cgroup
*from
;
1603 struct mem_cgroup
*to
;
1606 * Unlike task_move routines, we access mc.to, mc.from not under
1607 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1609 spin_lock(&mc
.lock
);
1615 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1616 || mem_cgroup_same_or_subtree(memcg
, to
);
1618 spin_unlock(&mc
.lock
);
1622 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1624 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1625 if (mem_cgroup_under_move(memcg
)) {
1627 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1628 /* moving charge context might have finished. */
1631 finish_wait(&mc
.waitq
, &wait
);
1639 * Take this lock when
1640 * - a code tries to modify page's memcg while it's USED.
1641 * - a code tries to modify page state accounting in a memcg.
1642 * see mem_cgroup_stolen(), too.
1644 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1645 unsigned long *flags
)
1647 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1650 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1651 unsigned long *flags
)
1653 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1656 #define K(x) ((x) << (PAGE_SHIFT-10))
1658 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1659 * @memcg: The memory cgroup that went over limit
1660 * @p: Task that is going to be killed
1662 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1665 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1668 * protects memcg_name and makes sure that parallel ooms do not
1671 static DEFINE_SPINLOCK(oom_info_lock
);
1672 struct cgroup
*task_cgrp
;
1673 struct cgroup
*mem_cgrp
;
1674 static char memcg_name
[PATH_MAX
];
1676 struct mem_cgroup
*iter
;
1682 spin_lock(&oom_info_lock
);
1685 mem_cgrp
= memcg
->css
.cgroup
;
1686 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1688 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1691 * Unfortunately, we are unable to convert to a useful name
1692 * But we'll still print out the usage information
1699 pr_info("Task in %s killed", memcg_name
);
1702 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1710 * Continues from above, so we don't need an KERN_ level
1712 pr_cont(" as a result of limit of %s\n", memcg_name
);
1715 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1716 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1717 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1718 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1719 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1720 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1721 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1722 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1723 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1724 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1725 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1726 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1728 for_each_mem_cgroup_tree(iter
, memcg
) {
1729 pr_info("Memory cgroup stats");
1732 ret
= cgroup_path(iter
->css
.cgroup
, memcg_name
, PATH_MAX
);
1734 pr_cont(" for %s", memcg_name
);
1738 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1739 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1741 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1742 K(mem_cgroup_read_stat(iter
, i
)));
1745 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1746 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1747 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1751 spin_unlock(&oom_info_lock
);
1755 * This function returns the number of memcg under hierarchy tree. Returns
1756 * 1(self count) if no children.
1758 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1761 struct mem_cgroup
*iter
;
1763 for_each_mem_cgroup_tree(iter
, memcg
)
1769 * Return the memory (and swap, if configured) limit for a memcg.
1771 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1775 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1778 * Do not consider swap space if we cannot swap due to swappiness
1780 if (mem_cgroup_swappiness(memcg
)) {
1783 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1784 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1787 * If memsw is finite and limits the amount of swap space
1788 * available to this memcg, return that limit.
1790 limit
= min(limit
, memsw
);
1796 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1799 struct mem_cgroup
*iter
;
1800 unsigned long chosen_points
= 0;
1801 unsigned long totalpages
;
1802 unsigned int points
= 0;
1803 struct task_struct
*chosen
= NULL
;
1806 * If current has a pending SIGKILL or is exiting, then automatically
1807 * select it. The goal is to allow it to allocate so that it may
1808 * quickly exit and free its memory.
1810 if (fatal_signal_pending(current
) || current
->flags
& PF_EXITING
) {
1811 set_thread_flag(TIF_MEMDIE
);
1815 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1816 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1817 for_each_mem_cgroup_tree(iter
, memcg
) {
1818 struct css_task_iter it
;
1819 struct task_struct
*task
;
1821 css_task_iter_start(&iter
->css
, &it
);
1822 while ((task
= css_task_iter_next(&it
))) {
1823 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1825 case OOM_SCAN_SELECT
:
1827 put_task_struct(chosen
);
1829 chosen_points
= ULONG_MAX
;
1830 get_task_struct(chosen
);
1832 case OOM_SCAN_CONTINUE
:
1834 case OOM_SCAN_ABORT
:
1835 css_task_iter_end(&it
);
1836 mem_cgroup_iter_break(memcg
, iter
);
1838 put_task_struct(chosen
);
1843 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1844 if (points
> chosen_points
) {
1846 put_task_struct(chosen
);
1848 chosen_points
= points
;
1849 get_task_struct(chosen
);
1852 css_task_iter_end(&it
);
1857 points
= chosen_points
* 1000 / totalpages
;
1858 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1859 NULL
, "Memory cgroup out of memory");
1862 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1864 unsigned long flags
)
1866 unsigned long total
= 0;
1867 bool noswap
= false;
1870 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1872 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1875 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1877 drain_all_stock_async(memcg
);
1878 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1880 * Allow limit shrinkers, which are triggered directly
1881 * by userspace, to catch signals and stop reclaim
1882 * after minimal progress, regardless of the margin.
1884 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1886 if (mem_cgroup_margin(memcg
))
1889 * If nothing was reclaimed after two attempts, there
1890 * may be no reclaimable pages in this hierarchy.
1899 * test_mem_cgroup_node_reclaimable
1900 * @memcg: the target memcg
1901 * @nid: the node ID to be checked.
1902 * @noswap : specify true here if the user wants flle only information.
1904 * This function returns whether the specified memcg contains any
1905 * reclaimable pages on a node. Returns true if there are any reclaimable
1906 * pages in the node.
1908 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1909 int nid
, bool noswap
)
1911 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1913 if (noswap
|| !total_swap_pages
)
1915 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1920 #if MAX_NUMNODES > 1
1923 * Always updating the nodemask is not very good - even if we have an empty
1924 * list or the wrong list here, we can start from some node and traverse all
1925 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1928 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1932 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1933 * pagein/pageout changes since the last update.
1935 if (!atomic_read(&memcg
->numainfo_events
))
1937 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1940 /* make a nodemask where this memcg uses memory from */
1941 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1943 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1945 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1946 node_clear(nid
, memcg
->scan_nodes
);
1949 atomic_set(&memcg
->numainfo_events
, 0);
1950 atomic_set(&memcg
->numainfo_updating
, 0);
1954 * Selecting a node where we start reclaim from. Because what we need is just
1955 * reducing usage counter, start from anywhere is O,K. Considering
1956 * memory reclaim from current node, there are pros. and cons.
1958 * Freeing memory from current node means freeing memory from a node which
1959 * we'll use or we've used. So, it may make LRU bad. And if several threads
1960 * hit limits, it will see a contention on a node. But freeing from remote
1961 * node means more costs for memory reclaim because of memory latency.
1963 * Now, we use round-robin. Better algorithm is welcomed.
1965 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1969 mem_cgroup_may_update_nodemask(memcg
);
1970 node
= memcg
->last_scanned_node
;
1972 node
= next_node(node
, memcg
->scan_nodes
);
1973 if (node
== MAX_NUMNODES
)
1974 node
= first_node(memcg
->scan_nodes
);
1976 * We call this when we hit limit, not when pages are added to LRU.
1977 * No LRU may hold pages because all pages are UNEVICTABLE or
1978 * memcg is too small and all pages are not on LRU. In that case,
1979 * we use curret node.
1981 if (unlikely(node
== MAX_NUMNODES
))
1982 node
= numa_node_id();
1984 memcg
->last_scanned_node
= node
;
1989 * Check all nodes whether it contains reclaimable pages or not.
1990 * For quick scan, we make use of scan_nodes. This will allow us to skip
1991 * unused nodes. But scan_nodes is lazily updated and may not cotain
1992 * enough new information. We need to do double check.
1994 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1999 * quick check...making use of scan_node.
2000 * We can skip unused nodes.
2002 if (!nodes_empty(memcg
->scan_nodes
)) {
2003 for (nid
= first_node(memcg
->scan_nodes
);
2005 nid
= next_node(nid
, memcg
->scan_nodes
)) {
2007 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
2012 * Check rest of nodes.
2014 for_each_node_state(nid
, N_MEMORY
) {
2015 if (node_isset(nid
, memcg
->scan_nodes
))
2017 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
2024 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
2029 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
2031 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
2035 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
2038 unsigned long *total_scanned
)
2040 struct mem_cgroup
*victim
= NULL
;
2043 unsigned long excess
;
2044 unsigned long nr_scanned
;
2045 struct mem_cgroup_reclaim_cookie reclaim
= {
2050 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
2053 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
2058 * If we have not been able to reclaim
2059 * anything, it might because there are
2060 * no reclaimable pages under this hierarchy
2065 * We want to do more targeted reclaim.
2066 * excess >> 2 is not to excessive so as to
2067 * reclaim too much, nor too less that we keep
2068 * coming back to reclaim from this cgroup
2070 if (total
>= (excess
>> 2) ||
2071 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
2076 if (!mem_cgroup_reclaimable(victim
, false))
2078 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
2080 *total_scanned
+= nr_scanned
;
2081 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
2084 mem_cgroup_iter_break(root_memcg
, victim
);
2088 #ifdef CONFIG_LOCKDEP
2089 static struct lockdep_map memcg_oom_lock_dep_map
= {
2090 .name
= "memcg_oom_lock",
2094 static DEFINE_SPINLOCK(memcg_oom_lock
);
2097 * Check OOM-Killer is already running under our hierarchy.
2098 * If someone is running, return false.
2100 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
2102 struct mem_cgroup
*iter
, *failed
= NULL
;
2104 spin_lock(&memcg_oom_lock
);
2106 for_each_mem_cgroup_tree(iter
, memcg
) {
2107 if (iter
->oom_lock
) {
2109 * this subtree of our hierarchy is already locked
2110 * so we cannot give a lock.
2113 mem_cgroup_iter_break(memcg
, iter
);
2116 iter
->oom_lock
= true;
2121 * OK, we failed to lock the whole subtree so we have
2122 * to clean up what we set up to the failing subtree
2124 for_each_mem_cgroup_tree(iter
, memcg
) {
2125 if (iter
== failed
) {
2126 mem_cgroup_iter_break(memcg
, iter
);
2129 iter
->oom_lock
= false;
2132 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
2134 spin_unlock(&memcg_oom_lock
);
2139 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2141 struct mem_cgroup
*iter
;
2143 spin_lock(&memcg_oom_lock
);
2144 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
2145 for_each_mem_cgroup_tree(iter
, memcg
)
2146 iter
->oom_lock
= false;
2147 spin_unlock(&memcg_oom_lock
);
2150 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2152 struct mem_cgroup
*iter
;
2154 for_each_mem_cgroup_tree(iter
, memcg
)
2155 atomic_inc(&iter
->under_oom
);
2158 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2160 struct mem_cgroup
*iter
;
2163 * When a new child is created while the hierarchy is under oom,
2164 * mem_cgroup_oom_lock() may not be called. We have to use
2165 * atomic_add_unless() here.
2167 for_each_mem_cgroup_tree(iter
, memcg
)
2168 atomic_add_unless(&iter
->under_oom
, -1, 0);
2171 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2173 struct oom_wait_info
{
2174 struct mem_cgroup
*memcg
;
2178 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2179 unsigned mode
, int sync
, void *arg
)
2181 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2182 struct mem_cgroup
*oom_wait_memcg
;
2183 struct oom_wait_info
*oom_wait_info
;
2185 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2186 oom_wait_memcg
= oom_wait_info
->memcg
;
2189 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2190 * Then we can use css_is_ancestor without taking care of RCU.
2192 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2193 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2195 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2198 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2200 atomic_inc(&memcg
->oom_wakeups
);
2201 /* for filtering, pass "memcg" as argument. */
2202 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2205 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2207 if (memcg
&& atomic_read(&memcg
->under_oom
))
2208 memcg_wakeup_oom(memcg
);
2211 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
2213 if (!current
->memcg_oom
.may_oom
)
2216 * We are in the middle of the charge context here, so we
2217 * don't want to block when potentially sitting on a callstack
2218 * that holds all kinds of filesystem and mm locks.
2220 * Also, the caller may handle a failed allocation gracefully
2221 * (like optional page cache readahead) and so an OOM killer
2222 * invocation might not even be necessary.
2224 * That's why we don't do anything here except remember the
2225 * OOM context and then deal with it at the end of the page
2226 * fault when the stack is unwound, the locks are released,
2227 * and when we know whether the fault was overall successful.
2229 css_get(&memcg
->css
);
2230 current
->memcg_oom
.memcg
= memcg
;
2231 current
->memcg_oom
.gfp_mask
= mask
;
2232 current
->memcg_oom
.order
= order
;
2236 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2237 * @handle: actually kill/wait or just clean up the OOM state
2239 * This has to be called at the end of a page fault if the memcg OOM
2240 * handler was enabled.
2242 * Memcg supports userspace OOM handling where failed allocations must
2243 * sleep on a waitqueue until the userspace task resolves the
2244 * situation. Sleeping directly in the charge context with all kinds
2245 * of locks held is not a good idea, instead we remember an OOM state
2246 * in the task and mem_cgroup_oom_synchronize() has to be called at
2247 * the end of the page fault to complete the OOM handling.
2249 * Returns %true if an ongoing memcg OOM situation was detected and
2250 * completed, %false otherwise.
2252 bool mem_cgroup_oom_synchronize(bool handle
)
2254 struct mem_cgroup
*memcg
= current
->memcg_oom
.memcg
;
2255 struct oom_wait_info owait
;
2258 /* OOM is global, do not handle */
2265 owait
.memcg
= memcg
;
2266 owait
.wait
.flags
= 0;
2267 owait
.wait
.func
= memcg_oom_wake_function
;
2268 owait
.wait
.private = current
;
2269 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2271 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2272 mem_cgroup_mark_under_oom(memcg
);
2274 locked
= mem_cgroup_oom_trylock(memcg
);
2277 mem_cgroup_oom_notify(memcg
);
2279 if (locked
&& !memcg
->oom_kill_disable
) {
2280 mem_cgroup_unmark_under_oom(memcg
);
2281 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2282 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom
.gfp_mask
,
2283 current
->memcg_oom
.order
);
2286 mem_cgroup_unmark_under_oom(memcg
);
2287 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2291 mem_cgroup_oom_unlock(memcg
);
2293 * There is no guarantee that an OOM-lock contender
2294 * sees the wakeups triggered by the OOM kill
2295 * uncharges. Wake any sleepers explicitely.
2297 memcg_oom_recover(memcg
);
2300 current
->memcg_oom
.memcg
= NULL
;
2301 css_put(&memcg
->css
);
2306 * Currently used to update mapped file statistics, but the routine can be
2307 * generalized to update other statistics as well.
2309 * Notes: Race condition
2311 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2312 * it tends to be costly. But considering some conditions, we doesn't need
2313 * to do so _always_.
2315 * Considering "charge", lock_page_cgroup() is not required because all
2316 * file-stat operations happen after a page is attached to radix-tree. There
2317 * are no race with "charge".
2319 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2320 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2321 * if there are race with "uncharge". Statistics itself is properly handled
2324 * Considering "move", this is an only case we see a race. To make the race
2325 * small, we check mm->moving_account and detect there are possibility of race
2326 * If there is, we take a lock.
2329 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2330 bool *locked
, unsigned long *flags
)
2332 struct mem_cgroup
*memcg
;
2333 struct page_cgroup
*pc
;
2335 pc
= lookup_page_cgroup(page
);
2337 memcg
= pc
->mem_cgroup
;
2338 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2341 * If this memory cgroup is not under account moving, we don't
2342 * need to take move_lock_mem_cgroup(). Because we already hold
2343 * rcu_read_lock(), any calls to move_account will be delayed until
2344 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2346 if (!mem_cgroup_stolen(memcg
))
2349 move_lock_mem_cgroup(memcg
, flags
);
2350 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2351 move_unlock_mem_cgroup(memcg
, flags
);
2357 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2359 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2362 * It's guaranteed that pc->mem_cgroup never changes while
2363 * lock is held because a routine modifies pc->mem_cgroup
2364 * should take move_lock_mem_cgroup().
2366 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2369 void mem_cgroup_update_page_stat(struct page
*page
,
2370 enum mem_cgroup_stat_index idx
, int val
)
2372 struct mem_cgroup
*memcg
;
2373 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2374 unsigned long uninitialized_var(flags
);
2376 if (mem_cgroup_disabled())
2379 VM_BUG_ON(!rcu_read_lock_held());
2380 memcg
= pc
->mem_cgroup
;
2381 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2384 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2388 * size of first charge trial. "32" comes from vmscan.c's magic value.
2389 * TODO: maybe necessary to use big numbers in big irons.
2391 #define CHARGE_BATCH 32U
2392 struct memcg_stock_pcp
{
2393 struct mem_cgroup
*cached
; /* this never be root cgroup */
2394 unsigned int nr_pages
;
2395 struct work_struct work
;
2396 unsigned long flags
;
2397 #define FLUSHING_CACHED_CHARGE 0
2399 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2400 static DEFINE_MUTEX(percpu_charge_mutex
);
2403 * consume_stock: Try to consume stocked charge on this cpu.
2404 * @memcg: memcg to consume from.
2405 * @nr_pages: how many pages to charge.
2407 * The charges will only happen if @memcg matches the current cpu's memcg
2408 * stock, and at least @nr_pages are available in that stock. Failure to
2409 * service an allocation will refill the stock.
2411 * returns true if successful, false otherwise.
2413 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2415 struct memcg_stock_pcp
*stock
;
2418 if (nr_pages
> CHARGE_BATCH
)
2421 stock
= &get_cpu_var(memcg_stock
);
2422 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2423 stock
->nr_pages
-= nr_pages
;
2424 else /* need to call res_counter_charge */
2426 put_cpu_var(memcg_stock
);
2431 * Returns stocks cached in percpu to res_counter and reset cached information.
2433 static void drain_stock(struct memcg_stock_pcp
*stock
)
2435 struct mem_cgroup
*old
= stock
->cached
;
2437 if (stock
->nr_pages
) {
2438 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2440 res_counter_uncharge(&old
->res
, bytes
);
2441 if (do_swap_account
)
2442 res_counter_uncharge(&old
->memsw
, bytes
);
2443 stock
->nr_pages
= 0;
2445 stock
->cached
= NULL
;
2449 * This must be called under preempt disabled or must be called by
2450 * a thread which is pinned to local cpu.
2452 static void drain_local_stock(struct work_struct
*dummy
)
2454 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2456 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2459 static void __init
memcg_stock_init(void)
2463 for_each_possible_cpu(cpu
) {
2464 struct memcg_stock_pcp
*stock
=
2465 &per_cpu(memcg_stock
, cpu
);
2466 INIT_WORK(&stock
->work
, drain_local_stock
);
2471 * Cache charges(val) which is from res_counter, to local per_cpu area.
2472 * This will be consumed by consume_stock() function, later.
2474 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2476 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2478 if (stock
->cached
!= memcg
) { /* reset if necessary */
2480 stock
->cached
= memcg
;
2482 stock
->nr_pages
+= nr_pages
;
2483 put_cpu_var(memcg_stock
);
2487 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2488 * of the hierarchy under it. sync flag says whether we should block
2489 * until the work is done.
2491 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2495 /* Notify other cpus that system-wide "drain" is running */
2498 for_each_online_cpu(cpu
) {
2499 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2500 struct mem_cgroup
*memcg
;
2502 memcg
= stock
->cached
;
2503 if (!memcg
|| !stock
->nr_pages
)
2505 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2507 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2509 drain_local_stock(&stock
->work
);
2511 schedule_work_on(cpu
, &stock
->work
);
2519 for_each_online_cpu(cpu
) {
2520 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2521 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2522 flush_work(&stock
->work
);
2529 * Tries to drain stocked charges in other cpus. This function is asynchronous
2530 * and just put a work per cpu for draining localy on each cpu. Caller can
2531 * expects some charges will be back to res_counter later but cannot wait for
2534 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2537 * If someone calls draining, avoid adding more kworker runs.
2539 if (!mutex_trylock(&percpu_charge_mutex
))
2541 drain_all_stock(root_memcg
, false);
2542 mutex_unlock(&percpu_charge_mutex
);
2545 /* This is a synchronous drain interface. */
2546 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2548 /* called when force_empty is called */
2549 mutex_lock(&percpu_charge_mutex
);
2550 drain_all_stock(root_memcg
, true);
2551 mutex_unlock(&percpu_charge_mutex
);
2555 * This function drains percpu counter value from DEAD cpu and
2556 * move it to local cpu. Note that this function can be preempted.
2558 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2562 spin_lock(&memcg
->pcp_counter_lock
);
2563 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2564 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2566 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2567 memcg
->nocpu_base
.count
[i
] += x
;
2569 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2570 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2572 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2573 memcg
->nocpu_base
.events
[i
] += x
;
2575 spin_unlock(&memcg
->pcp_counter_lock
);
2578 static int memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2579 unsigned long action
,
2582 int cpu
= (unsigned long)hcpu
;
2583 struct memcg_stock_pcp
*stock
;
2584 struct mem_cgroup
*iter
;
2586 if (action
== CPU_ONLINE
)
2589 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2592 for_each_mem_cgroup(iter
)
2593 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2595 stock
= &per_cpu(memcg_stock
, cpu
);
2601 /* See __mem_cgroup_try_charge() for details */
2603 CHARGE_OK
, /* success */
2604 CHARGE_RETRY
, /* need to retry but retry is not bad */
2605 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2606 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2609 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2610 unsigned int nr_pages
, unsigned int min_pages
,
2613 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2614 struct mem_cgroup
*mem_over_limit
;
2615 struct res_counter
*fail_res
;
2616 unsigned long flags
= 0;
2619 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2622 if (!do_swap_account
)
2624 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2628 res_counter_uncharge(&memcg
->res
, csize
);
2629 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2630 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2632 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2634 * Never reclaim on behalf of optional batching, retry with a
2635 * single page instead.
2637 if (nr_pages
> min_pages
)
2638 return CHARGE_RETRY
;
2640 if (!(gfp_mask
& __GFP_WAIT
))
2641 return CHARGE_WOULDBLOCK
;
2643 if (gfp_mask
& __GFP_NORETRY
)
2644 return CHARGE_NOMEM
;
2646 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2647 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2648 return CHARGE_RETRY
;
2650 * Even though the limit is exceeded at this point, reclaim
2651 * may have been able to free some pages. Retry the charge
2652 * before killing the task.
2654 * Only for regular pages, though: huge pages are rather
2655 * unlikely to succeed so close to the limit, and we fall back
2656 * to regular pages anyway in case of failure.
2658 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2659 return CHARGE_RETRY
;
2662 * At task move, charge accounts can be doubly counted. So, it's
2663 * better to wait until the end of task_move if something is going on.
2665 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2666 return CHARGE_RETRY
;
2669 mem_cgroup_oom(mem_over_limit
, gfp_mask
, get_order(csize
));
2671 return CHARGE_NOMEM
;
2675 * __mem_cgroup_try_charge() does
2676 * 1. detect memcg to be charged against from passed *mm and *ptr,
2677 * 2. update res_counter
2678 * 3. call memory reclaim if necessary.
2680 * In some special case, if the task is fatal, fatal_signal_pending() or
2681 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2682 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2683 * as possible without any hazards. 2: all pages should have a valid
2684 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2685 * pointer, that is treated as a charge to root_mem_cgroup.
2687 * So __mem_cgroup_try_charge() will return
2688 * 0 ... on success, filling *ptr with a valid memcg pointer.
2689 * -ENOMEM ... charge failure because of resource limits.
2690 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2692 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2693 * the oom-killer can be invoked.
2695 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2697 unsigned int nr_pages
,
2698 struct mem_cgroup
**ptr
,
2701 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2702 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2703 struct mem_cgroup
*memcg
= NULL
;
2707 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2708 * in system level. So, allow to go ahead dying process in addition to
2711 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2712 || fatal_signal_pending(current
)))
2715 if (unlikely(task_in_memcg_oom(current
)))
2718 if (gfp_mask
& __GFP_NOFAIL
)
2722 * We always charge the cgroup the mm_struct belongs to.
2723 * The mm_struct's mem_cgroup changes on task migration if the
2724 * thread group leader migrates. It's possible that mm is not
2725 * set, if so charge the root memcg (happens for pagecache usage).
2728 *ptr
= root_mem_cgroup
;
2730 if (*ptr
) { /* css should be a valid one */
2732 if (mem_cgroup_is_root(memcg
))
2734 if (consume_stock(memcg
, nr_pages
))
2736 css_get(&memcg
->css
);
2738 struct task_struct
*p
;
2741 p
= rcu_dereference(mm
->owner
);
2743 * Because we don't have task_lock(), "p" can exit.
2744 * In that case, "memcg" can point to root or p can be NULL with
2745 * race with swapoff. Then, we have small risk of mis-accouning.
2746 * But such kind of mis-account by race always happens because
2747 * we don't have cgroup_mutex(). It's overkill and we allo that
2749 * (*) swapoff at el will charge against mm-struct not against
2750 * task-struct. So, mm->owner can be NULL.
2752 memcg
= mem_cgroup_from_task(p
);
2754 memcg
= root_mem_cgroup
;
2755 if (mem_cgroup_is_root(memcg
)) {
2759 if (consume_stock(memcg
, nr_pages
)) {
2761 * It seems dagerous to access memcg without css_get().
2762 * But considering how consume_stok works, it's not
2763 * necessary. If consume_stock success, some charges
2764 * from this memcg are cached on this cpu. So, we
2765 * don't need to call css_get()/css_tryget() before
2766 * calling consume_stock().
2771 /* after here, we may be blocked. we need to get refcnt */
2772 if (!css_tryget(&memcg
->css
)) {
2780 bool invoke_oom
= oom
&& !nr_oom_retries
;
2782 /* If killed, bypass charge */
2783 if (fatal_signal_pending(current
)) {
2784 css_put(&memcg
->css
);
2788 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
,
2789 nr_pages
, invoke_oom
);
2793 case CHARGE_RETRY
: /* not in OOM situation but retry */
2795 css_put(&memcg
->css
);
2798 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2799 css_put(&memcg
->css
);
2801 case CHARGE_NOMEM
: /* OOM routine works */
2802 if (!oom
|| invoke_oom
) {
2803 css_put(&memcg
->css
);
2809 } while (ret
!= CHARGE_OK
);
2811 if (batch
> nr_pages
)
2812 refill_stock(memcg
, batch
- nr_pages
);
2813 css_put(&memcg
->css
);
2818 if (!(gfp_mask
& __GFP_NOFAIL
)) {
2823 *ptr
= root_mem_cgroup
;
2828 * Somemtimes we have to undo a charge we got by try_charge().
2829 * This function is for that and do uncharge, put css's refcnt.
2830 * gotten by try_charge().
2832 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2833 unsigned int nr_pages
)
2835 if (!mem_cgroup_is_root(memcg
)) {
2836 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2838 res_counter_uncharge(&memcg
->res
, bytes
);
2839 if (do_swap_account
)
2840 res_counter_uncharge(&memcg
->memsw
, bytes
);
2845 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2846 * This is useful when moving usage to parent cgroup.
2848 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2849 unsigned int nr_pages
)
2851 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2853 if (mem_cgroup_is_root(memcg
))
2856 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2857 if (do_swap_account
)
2858 res_counter_uncharge_until(&memcg
->memsw
,
2859 memcg
->memsw
.parent
, bytes
);
2863 * A helper function to get mem_cgroup from ID. must be called under
2864 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2865 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2866 * called against removed memcg.)
2868 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2870 /* ID 0 is unused ID */
2873 return mem_cgroup_from_id(id
);
2876 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2878 struct mem_cgroup
*memcg
= NULL
;
2879 struct page_cgroup
*pc
;
2883 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
2885 pc
= lookup_page_cgroup(page
);
2886 lock_page_cgroup(pc
);
2887 if (PageCgroupUsed(pc
)) {
2888 memcg
= pc
->mem_cgroup
;
2889 if (memcg
&& !css_tryget(&memcg
->css
))
2891 } else if (PageSwapCache(page
)) {
2892 ent
.val
= page_private(page
);
2893 id
= lookup_swap_cgroup_id(ent
);
2895 memcg
= mem_cgroup_lookup(id
);
2896 if (memcg
&& !css_tryget(&memcg
->css
))
2900 unlock_page_cgroup(pc
);
2904 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2906 unsigned int nr_pages
,
2907 enum charge_type ctype
,
2910 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2911 struct zone
*uninitialized_var(zone
);
2912 struct lruvec
*lruvec
;
2913 bool was_on_lru
= false;
2916 lock_page_cgroup(pc
);
2917 VM_BUG_ON_PAGE(PageCgroupUsed(pc
), page
);
2919 * we don't need page_cgroup_lock about tail pages, becase they are not
2920 * accessed by any other context at this point.
2924 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2925 * may already be on some other mem_cgroup's LRU. Take care of it.
2928 zone
= page_zone(page
);
2929 spin_lock_irq(&zone
->lru_lock
);
2930 if (PageLRU(page
)) {
2931 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2933 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2938 pc
->mem_cgroup
= memcg
;
2940 * We access a page_cgroup asynchronously without lock_page_cgroup().
2941 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2942 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2943 * before USED bit, we need memory barrier here.
2944 * See mem_cgroup_add_lru_list(), etc.
2947 SetPageCgroupUsed(pc
);
2951 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2952 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2954 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2956 spin_unlock_irq(&zone
->lru_lock
);
2959 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2964 mem_cgroup_charge_statistics(memcg
, page
, anon
, nr_pages
);
2965 unlock_page_cgroup(pc
);
2968 * "charge_statistics" updated event counter. Then, check it.
2969 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2970 * if they exceeds softlimit.
2972 memcg_check_events(memcg
, page
);
2975 static DEFINE_MUTEX(set_limit_mutex
);
2977 #ifdef CONFIG_MEMCG_KMEM
2978 static DEFINE_MUTEX(activate_kmem_mutex
);
2980 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2982 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
2983 memcg_kmem_is_active(memcg
);
2987 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2988 * in the memcg_cache_params struct.
2990 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2992 struct kmem_cache
*cachep
;
2994 VM_BUG_ON(p
->is_root_cache
);
2995 cachep
= p
->root_cache
;
2996 return cache_from_memcg_idx(cachep
, memcg_cache_id(p
->memcg
));
2999 #ifdef CONFIG_SLABINFO
3000 static int mem_cgroup_slabinfo_read(struct seq_file
*m
, void *v
)
3002 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3003 struct memcg_cache_params
*params
;
3005 if (!memcg_can_account_kmem(memcg
))
3008 print_slabinfo_header(m
);
3010 mutex_lock(&memcg
->slab_caches_mutex
);
3011 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
3012 cache_show(memcg_params_to_cache(params
), m
);
3013 mutex_unlock(&memcg
->slab_caches_mutex
);
3019 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
3021 struct res_counter
*fail_res
;
3022 struct mem_cgroup
*_memcg
;
3025 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
3030 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
3031 &_memcg
, oom_gfp_allowed(gfp
));
3033 if (ret
== -EINTR
) {
3035 * __mem_cgroup_try_charge() chosed to bypass to root due to
3036 * OOM kill or fatal signal. Since our only options are to
3037 * either fail the allocation or charge it to this cgroup, do
3038 * it as a temporary condition. But we can't fail. From a
3039 * kmem/slab perspective, the cache has already been selected,
3040 * by mem_cgroup_kmem_get_cache(), so it is too late to change
3043 * This condition will only trigger if the task entered
3044 * memcg_charge_kmem in a sane state, but was OOM-killed during
3045 * __mem_cgroup_try_charge() above. Tasks that were already
3046 * dying when the allocation triggers should have been already
3047 * directed to the root cgroup in memcontrol.h
3049 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
3050 if (do_swap_account
)
3051 res_counter_charge_nofail(&memcg
->memsw
, size
,
3055 res_counter_uncharge(&memcg
->kmem
, size
);
3060 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
3062 res_counter_uncharge(&memcg
->res
, size
);
3063 if (do_swap_account
)
3064 res_counter_uncharge(&memcg
->memsw
, size
);
3067 if (res_counter_uncharge(&memcg
->kmem
, size
))
3071 * Releases a reference taken in kmem_cgroup_css_offline in case
3072 * this last uncharge is racing with the offlining code or it is
3073 * outliving the memcg existence.
3075 * The memory barrier imposed by test&clear is paired with the
3076 * explicit one in memcg_kmem_mark_dead().
3078 if (memcg_kmem_test_and_clear_dead(memcg
))
3079 css_put(&memcg
->css
);
3083 * helper for acessing a memcg's index. It will be used as an index in the
3084 * child cache array in kmem_cache, and also to derive its name. This function
3085 * will return -1 when this is not a kmem-limited memcg.
3087 int memcg_cache_id(struct mem_cgroup
*memcg
)
3089 return memcg
? memcg
->kmemcg_id
: -1;
3092 static size_t memcg_caches_array_size(int num_groups
)
3095 if (num_groups
<= 0)
3098 size
= 2 * num_groups
;
3099 if (size
< MEMCG_CACHES_MIN_SIZE
)
3100 size
= MEMCG_CACHES_MIN_SIZE
;
3101 else if (size
> MEMCG_CACHES_MAX_SIZE
)
3102 size
= MEMCG_CACHES_MAX_SIZE
;
3108 * We should update the current array size iff all caches updates succeed. This
3109 * can only be done from the slab side. The slab mutex needs to be held when
3112 void memcg_update_array_size(int num
)
3114 if (num
> memcg_limited_groups_array_size
)
3115 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3118 static void kmem_cache_destroy_work_func(struct work_struct
*w
);
3120 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3122 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3124 VM_BUG_ON(!is_root_cache(s
));
3126 if (num_groups
> memcg_limited_groups_array_size
) {
3128 struct memcg_cache_params
*new_params
;
3129 ssize_t size
= memcg_caches_array_size(num_groups
);
3131 size
*= sizeof(void *);
3132 size
+= offsetof(struct memcg_cache_params
, memcg_caches
);
3134 new_params
= kzalloc(size
, GFP_KERNEL
);
3138 new_params
->is_root_cache
= true;
3141 * There is the chance it will be bigger than
3142 * memcg_limited_groups_array_size, if we failed an allocation
3143 * in a cache, in which case all caches updated before it, will
3144 * have a bigger array.
3146 * But if that is the case, the data after
3147 * memcg_limited_groups_array_size is certainly unused
3149 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3150 if (!cur_params
->memcg_caches
[i
])
3152 new_params
->memcg_caches
[i
] =
3153 cur_params
->memcg_caches
[i
];
3157 * Ideally, we would wait until all caches succeed, and only
3158 * then free the old one. But this is not worth the extra
3159 * pointer per-cache we'd have to have for this.
3161 * It is not a big deal if some caches are left with a size
3162 * bigger than the others. And all updates will reset this
3165 rcu_assign_pointer(s
->memcg_params
, new_params
);
3167 kfree_rcu(cur_params
, rcu_head
);
3172 int memcg_alloc_cache_params(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3173 struct kmem_cache
*root_cache
)
3177 if (!memcg_kmem_enabled())
3181 size
= offsetof(struct memcg_cache_params
, memcg_caches
);
3182 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3184 size
= sizeof(struct memcg_cache_params
);
3186 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3187 if (!s
->memcg_params
)
3191 s
->memcg_params
->memcg
= memcg
;
3192 s
->memcg_params
->root_cache
= root_cache
;
3193 INIT_WORK(&s
->memcg_params
->destroy
,
3194 kmem_cache_destroy_work_func
);
3196 s
->memcg_params
->is_root_cache
= true;
3201 void memcg_free_cache_params(struct kmem_cache
*s
)
3203 kfree(s
->memcg_params
);
3206 void memcg_register_cache(struct kmem_cache
*s
)
3208 struct kmem_cache
*root
;
3209 struct mem_cgroup
*memcg
;
3212 if (is_root_cache(s
))
3216 * Holding the slab_mutex assures nobody will touch the memcg_caches
3217 * array while we are modifying it.
3219 lockdep_assert_held(&slab_mutex
);
3221 root
= s
->memcg_params
->root_cache
;
3222 memcg
= s
->memcg_params
->memcg
;
3223 id
= memcg_cache_id(memcg
);
3225 css_get(&memcg
->css
);
3229 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3230 * barrier here to ensure nobody will see the kmem_cache partially
3236 * Initialize the pointer to this cache in its parent's memcg_params
3237 * before adding it to the memcg_slab_caches list, otherwise we can
3238 * fail to convert memcg_params_to_cache() while traversing the list.
3240 VM_BUG_ON(root
->memcg_params
->memcg_caches
[id
]);
3241 root
->memcg_params
->memcg_caches
[id
] = s
;
3243 mutex_lock(&memcg
->slab_caches_mutex
);
3244 list_add(&s
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
3245 mutex_unlock(&memcg
->slab_caches_mutex
);
3248 void memcg_unregister_cache(struct kmem_cache
*s
)
3250 struct kmem_cache
*root
;
3251 struct mem_cgroup
*memcg
;
3254 if (is_root_cache(s
))
3258 * Holding the slab_mutex assures nobody will touch the memcg_caches
3259 * array while we are modifying it.
3261 lockdep_assert_held(&slab_mutex
);
3263 root
= s
->memcg_params
->root_cache
;
3264 memcg
= s
->memcg_params
->memcg
;
3265 id
= memcg_cache_id(memcg
);
3267 mutex_lock(&memcg
->slab_caches_mutex
);
3268 list_del(&s
->memcg_params
->list
);
3269 mutex_unlock(&memcg
->slab_caches_mutex
);
3272 * Clear the pointer to this cache in its parent's memcg_params only
3273 * after removing it from the memcg_slab_caches list, otherwise we can
3274 * fail to convert memcg_params_to_cache() while traversing the list.
3276 VM_BUG_ON(!root
->memcg_params
->memcg_caches
[id
]);
3277 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3279 css_put(&memcg
->css
);
3283 * During the creation a new cache, we need to disable our accounting mechanism
3284 * altogether. This is true even if we are not creating, but rather just
3285 * enqueing new caches to be created.
3287 * This is because that process will trigger allocations; some visible, like
3288 * explicit kmallocs to auxiliary data structures, name strings and internal
3289 * cache structures; some well concealed, like INIT_WORK() that can allocate
3290 * objects during debug.
3292 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3293 * to it. This may not be a bounded recursion: since the first cache creation
3294 * failed to complete (waiting on the allocation), we'll just try to create the
3295 * cache again, failing at the same point.
3297 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3298 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3299 * inside the following two functions.
3301 static inline void memcg_stop_kmem_account(void)
3303 VM_BUG_ON(!current
->mm
);
3304 current
->memcg_kmem_skip_account
++;
3307 static inline void memcg_resume_kmem_account(void)
3309 VM_BUG_ON(!current
->mm
);
3310 current
->memcg_kmem_skip_account
--;
3313 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3315 struct kmem_cache
*cachep
;
3316 struct memcg_cache_params
*p
;
3318 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3320 cachep
= memcg_params_to_cache(p
);
3323 * If we get down to 0 after shrink, we could delete right away.
3324 * However, memcg_release_pages() already puts us back in the workqueue
3325 * in that case. If we proceed deleting, we'll get a dangling
3326 * reference, and removing the object from the workqueue in that case
3327 * is unnecessary complication. We are not a fast path.
3329 * Note that this case is fundamentally different from racing with
3330 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3331 * kmem_cache_shrink, not only we would be reinserting a dead cache
3332 * into the queue, but doing so from inside the worker racing to
3335 * So if we aren't down to zero, we'll just schedule a worker and try
3338 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0) {
3339 kmem_cache_shrink(cachep
);
3340 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
3343 kmem_cache_destroy(cachep
);
3346 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3348 if (!cachep
->memcg_params
->dead
)
3352 * There are many ways in which we can get here.
3354 * We can get to a memory-pressure situation while the delayed work is
3355 * still pending to run. The vmscan shrinkers can then release all
3356 * cache memory and get us to destruction. If this is the case, we'll
3357 * be executed twice, which is a bug (the second time will execute over
3358 * bogus data). In this case, cancelling the work should be fine.
3360 * But we can also get here from the worker itself, if
3361 * kmem_cache_shrink is enough to shake all the remaining objects and
3362 * get the page count to 0. In this case, we'll deadlock if we try to
3363 * cancel the work (the worker runs with an internal lock held, which
3364 * is the same lock we would hold for cancel_work_sync().)
3366 * Since we can't possibly know who got us here, just refrain from
3367 * running if there is already work pending
3369 if (work_pending(&cachep
->memcg_params
->destroy
))
3372 * We have to defer the actual destroying to a workqueue, because
3373 * we might currently be in a context that cannot sleep.
3375 schedule_work(&cachep
->memcg_params
->destroy
);
3378 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3379 struct kmem_cache
*s
)
3381 struct kmem_cache
*new;
3382 static char *tmp_name
= NULL
;
3383 static DEFINE_MUTEX(mutex
); /* protects tmp_name */
3385 BUG_ON(!memcg_can_account_kmem(memcg
));
3389 * kmem_cache_create_memcg duplicates the given name and
3390 * cgroup_name for this name requires RCU context.
3391 * This static temporary buffer is used to prevent from
3392 * pointless shortliving allocation.
3395 tmp_name
= kmalloc(PATH_MAX
, GFP_KERNEL
);
3401 snprintf(tmp_name
, PATH_MAX
, "%s(%d:%s)", s
->name
,
3402 memcg_cache_id(memcg
), cgroup_name(memcg
->css
.cgroup
));
3405 new = kmem_cache_create_memcg(memcg
, tmp_name
, s
->object_size
, s
->align
,
3406 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3409 new->allocflags
|= __GFP_KMEMCG
;
3413 mutex_unlock(&mutex
);
3417 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3419 struct kmem_cache
*c
;
3422 if (!s
->memcg_params
)
3424 if (!s
->memcg_params
->is_root_cache
)
3428 * If the cache is being destroyed, we trust that there is no one else
3429 * requesting objects from it. Even if there are, the sanity checks in
3430 * kmem_cache_destroy should caught this ill-case.
3432 * Still, we don't want anyone else freeing memcg_caches under our
3433 * noses, which can happen if a new memcg comes to life. As usual,
3434 * we'll take the activate_kmem_mutex to protect ourselves against
3437 mutex_lock(&activate_kmem_mutex
);
3438 for_each_memcg_cache_index(i
) {
3439 c
= cache_from_memcg_idx(s
, i
);
3444 * We will now manually delete the caches, so to avoid races
3445 * we need to cancel all pending destruction workers and
3446 * proceed with destruction ourselves.
3448 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3449 * and that could spawn the workers again: it is likely that
3450 * the cache still have active pages until this very moment.
3451 * This would lead us back to mem_cgroup_destroy_cache.
3453 * But that will not execute at all if the "dead" flag is not
3454 * set, so flip it down to guarantee we are in control.
3456 c
->memcg_params
->dead
= false;
3457 cancel_work_sync(&c
->memcg_params
->destroy
);
3458 kmem_cache_destroy(c
);
3460 mutex_unlock(&activate_kmem_mutex
);
3463 struct create_work
{
3464 struct mem_cgroup
*memcg
;
3465 struct kmem_cache
*cachep
;
3466 struct work_struct work
;
3469 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3471 struct kmem_cache
*cachep
;
3472 struct memcg_cache_params
*params
;
3474 if (!memcg_kmem_is_active(memcg
))
3477 mutex_lock(&memcg
->slab_caches_mutex
);
3478 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3479 cachep
= memcg_params_to_cache(params
);
3480 cachep
->memcg_params
->dead
= true;
3481 schedule_work(&cachep
->memcg_params
->destroy
);
3483 mutex_unlock(&memcg
->slab_caches_mutex
);
3486 static void memcg_create_cache_work_func(struct work_struct
*w
)
3488 struct create_work
*cw
;
3490 cw
= container_of(w
, struct create_work
, work
);
3491 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3492 css_put(&cw
->memcg
->css
);
3497 * Enqueue the creation of a per-memcg kmem_cache.
3499 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3500 struct kmem_cache
*cachep
)
3502 struct create_work
*cw
;
3504 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3506 css_put(&memcg
->css
);
3511 cw
->cachep
= cachep
;
3513 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3514 schedule_work(&cw
->work
);
3517 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3518 struct kmem_cache
*cachep
)
3521 * We need to stop accounting when we kmalloc, because if the
3522 * corresponding kmalloc cache is not yet created, the first allocation
3523 * in __memcg_create_cache_enqueue will recurse.
3525 * However, it is better to enclose the whole function. Depending on
3526 * the debugging options enabled, INIT_WORK(), for instance, can
3527 * trigger an allocation. This too, will make us recurse. Because at
3528 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3529 * the safest choice is to do it like this, wrapping the whole function.
3531 memcg_stop_kmem_account();
3532 __memcg_create_cache_enqueue(memcg
, cachep
);
3533 memcg_resume_kmem_account();
3536 * Return the kmem_cache we're supposed to use for a slab allocation.
3537 * We try to use the current memcg's version of the cache.
3539 * If the cache does not exist yet, if we are the first user of it,
3540 * we either create it immediately, if possible, or create it asynchronously
3542 * In the latter case, we will let the current allocation go through with
3543 * the original cache.
3545 * Can't be called in interrupt context or from kernel threads.
3546 * This function needs to be called with rcu_read_lock() held.
3548 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3551 struct mem_cgroup
*memcg
;
3552 struct kmem_cache
*memcg_cachep
;
3554 VM_BUG_ON(!cachep
->memcg_params
);
3555 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3557 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3561 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3563 if (!memcg_can_account_kmem(memcg
))
3566 memcg_cachep
= cache_from_memcg_idx(cachep
, memcg_cache_id(memcg
));
3567 if (likely(memcg_cachep
)) {
3568 cachep
= memcg_cachep
;
3572 /* The corresponding put will be done in the workqueue. */
3573 if (!css_tryget(&memcg
->css
))
3578 * If we are in a safe context (can wait, and not in interrupt
3579 * context), we could be be predictable and return right away.
3580 * This would guarantee that the allocation being performed
3581 * already belongs in the new cache.
3583 * However, there are some clashes that can arrive from locking.
3584 * For instance, because we acquire the slab_mutex while doing
3585 * kmem_cache_dup, this means no further allocation could happen
3586 * with the slab_mutex held.
3588 * Also, because cache creation issue get_online_cpus(), this
3589 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3590 * that ends up reversed during cpu hotplug. (cpuset allocates
3591 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3592 * better to defer everything.
3594 memcg_create_cache_enqueue(memcg
, cachep
);
3600 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3603 * We need to verify if the allocation against current->mm->owner's memcg is
3604 * possible for the given order. But the page is not allocated yet, so we'll
3605 * need a further commit step to do the final arrangements.
3607 * It is possible for the task to switch cgroups in this mean time, so at
3608 * commit time, we can't rely on task conversion any longer. We'll then use
3609 * the handle argument to return to the caller which cgroup we should commit
3610 * against. We could also return the memcg directly and avoid the pointer
3611 * passing, but a boolean return value gives better semantics considering
3612 * the compiled-out case as well.
3614 * Returning true means the allocation is possible.
3617 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3619 struct mem_cgroup
*memcg
;
3625 * Disabling accounting is only relevant for some specific memcg
3626 * internal allocations. Therefore we would initially not have such
3627 * check here, since direct calls to the page allocator that are marked
3628 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3629 * concerned with cache allocations, and by having this test at
3630 * memcg_kmem_get_cache, we are already able to relay the allocation to
3631 * the root cache and bypass the memcg cache altogether.
3633 * There is one exception, though: the SLUB allocator does not create
3634 * large order caches, but rather service large kmallocs directly from
3635 * the page allocator. Therefore, the following sequence when backed by
3636 * the SLUB allocator:
3638 * memcg_stop_kmem_account();
3639 * kmalloc(<large_number>)
3640 * memcg_resume_kmem_account();
3642 * would effectively ignore the fact that we should skip accounting,
3643 * since it will drive us directly to this function without passing
3644 * through the cache selector memcg_kmem_get_cache. Such large
3645 * allocations are extremely rare but can happen, for instance, for the
3646 * cache arrays. We bring this test here.
3648 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3651 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3654 * very rare case described in mem_cgroup_from_task. Unfortunately there
3655 * isn't much we can do without complicating this too much, and it would
3656 * be gfp-dependent anyway. Just let it go
3658 if (unlikely(!memcg
))
3661 if (!memcg_can_account_kmem(memcg
)) {
3662 css_put(&memcg
->css
);
3666 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3670 css_put(&memcg
->css
);
3674 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3677 struct page_cgroup
*pc
;
3679 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3681 /* The page allocation failed. Revert */
3683 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3687 pc
= lookup_page_cgroup(page
);
3688 lock_page_cgroup(pc
);
3689 pc
->mem_cgroup
= memcg
;
3690 SetPageCgroupUsed(pc
);
3691 unlock_page_cgroup(pc
);
3694 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3696 struct mem_cgroup
*memcg
= NULL
;
3697 struct page_cgroup
*pc
;
3700 pc
= lookup_page_cgroup(page
);
3702 * Fast unlocked return. Theoretically might have changed, have to
3703 * check again after locking.
3705 if (!PageCgroupUsed(pc
))
3708 lock_page_cgroup(pc
);
3709 if (PageCgroupUsed(pc
)) {
3710 memcg
= pc
->mem_cgroup
;
3711 ClearPageCgroupUsed(pc
);
3713 unlock_page_cgroup(pc
);
3716 * We trust that only if there is a memcg associated with the page, it
3717 * is a valid allocation
3722 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
3723 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3726 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3729 #endif /* CONFIG_MEMCG_KMEM */
3731 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3733 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3735 * Because tail pages are not marked as "used", set it. We're under
3736 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3737 * charge/uncharge will be never happen and move_account() is done under
3738 * compound_lock(), so we don't have to take care of races.
3740 void mem_cgroup_split_huge_fixup(struct page
*head
)
3742 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3743 struct page_cgroup
*pc
;
3744 struct mem_cgroup
*memcg
;
3747 if (mem_cgroup_disabled())
3750 memcg
= head_pc
->mem_cgroup
;
3751 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3753 pc
->mem_cgroup
= memcg
;
3754 smp_wmb();/* see __commit_charge() */
3755 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3757 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
3760 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3763 void mem_cgroup_move_account_page_stat(struct mem_cgroup
*from
,
3764 struct mem_cgroup
*to
,
3765 unsigned int nr_pages
,
3766 enum mem_cgroup_stat_index idx
)
3768 /* Update stat data for mem_cgroup */
3770 __this_cpu_sub(from
->stat
->count
[idx
], nr_pages
);
3771 __this_cpu_add(to
->stat
->count
[idx
], nr_pages
);
3776 * mem_cgroup_move_account - move account of the page
3778 * @nr_pages: number of regular pages (>1 for huge pages)
3779 * @pc: page_cgroup of the page.
3780 * @from: mem_cgroup which the page is moved from.
3781 * @to: mem_cgroup which the page is moved to. @from != @to.
3783 * The caller must confirm following.
3784 * - page is not on LRU (isolate_page() is useful.)
3785 * - compound_lock is held when nr_pages > 1
3787 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3790 static int mem_cgroup_move_account(struct page
*page
,
3791 unsigned int nr_pages
,
3792 struct page_cgroup
*pc
,
3793 struct mem_cgroup
*from
,
3794 struct mem_cgroup
*to
)
3796 unsigned long flags
;
3798 bool anon
= PageAnon(page
);
3800 VM_BUG_ON(from
== to
);
3801 VM_BUG_ON_PAGE(PageLRU(page
), page
);
3803 * The page is isolated from LRU. So, collapse function
3804 * will not handle this page. But page splitting can happen.
3805 * Do this check under compound_page_lock(). The caller should
3809 if (nr_pages
> 1 && !PageTransHuge(page
))
3812 lock_page_cgroup(pc
);
3815 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3818 move_lock_mem_cgroup(from
, &flags
);
3820 if (!anon
&& page_mapped(page
))
3821 mem_cgroup_move_account_page_stat(from
, to
, nr_pages
,
3822 MEM_CGROUP_STAT_FILE_MAPPED
);
3824 if (PageWriteback(page
))
3825 mem_cgroup_move_account_page_stat(from
, to
, nr_pages
,
3826 MEM_CGROUP_STAT_WRITEBACK
);
3828 mem_cgroup_charge_statistics(from
, page
, anon
, -nr_pages
);
3830 /* caller should have done css_get */
3831 pc
->mem_cgroup
= to
;
3832 mem_cgroup_charge_statistics(to
, page
, anon
, nr_pages
);
3833 move_unlock_mem_cgroup(from
, &flags
);
3836 unlock_page_cgroup(pc
);
3840 memcg_check_events(to
, page
);
3841 memcg_check_events(from
, page
);
3847 * mem_cgroup_move_parent - moves page to the parent group
3848 * @page: the page to move
3849 * @pc: page_cgroup of the page
3850 * @child: page's cgroup
3852 * move charges to its parent or the root cgroup if the group has no
3853 * parent (aka use_hierarchy==0).
3854 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3855 * mem_cgroup_move_account fails) the failure is always temporary and
3856 * it signals a race with a page removal/uncharge or migration. In the
3857 * first case the page is on the way out and it will vanish from the LRU
3858 * on the next attempt and the call should be retried later.
3859 * Isolation from the LRU fails only if page has been isolated from
3860 * the LRU since we looked at it and that usually means either global
3861 * reclaim or migration going on. The page will either get back to the
3863 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3864 * (!PageCgroupUsed) or moved to a different group. The page will
3865 * disappear in the next attempt.
3867 static int mem_cgroup_move_parent(struct page
*page
,
3868 struct page_cgroup
*pc
,
3869 struct mem_cgroup
*child
)
3871 struct mem_cgroup
*parent
;
3872 unsigned int nr_pages
;
3873 unsigned long uninitialized_var(flags
);
3876 VM_BUG_ON(mem_cgroup_is_root(child
));
3879 if (!get_page_unless_zero(page
))
3881 if (isolate_lru_page(page
))
3884 nr_pages
= hpage_nr_pages(page
);
3886 parent
= parent_mem_cgroup(child
);
3888 * If no parent, move charges to root cgroup.
3891 parent
= root_mem_cgroup
;
3894 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
3895 flags
= compound_lock_irqsave(page
);
3898 ret
= mem_cgroup_move_account(page
, nr_pages
,
3901 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3904 compound_unlock_irqrestore(page
, flags
);
3905 putback_lru_page(page
);
3913 * Charge the memory controller for page usage.
3915 * 0 if the charge was successful
3916 * < 0 if the cgroup is over its limit
3918 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
3919 gfp_t gfp_mask
, enum charge_type ctype
)
3921 struct mem_cgroup
*memcg
= NULL
;
3922 unsigned int nr_pages
= 1;
3926 if (PageTransHuge(page
)) {
3927 nr_pages
<<= compound_order(page
);
3928 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
3930 * Never OOM-kill a process for a huge page. The
3931 * fault handler will fall back to regular pages.
3936 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
3939 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
3943 int mem_cgroup_newpage_charge(struct page
*page
,
3944 struct mm_struct
*mm
, gfp_t gfp_mask
)
3946 if (mem_cgroup_disabled())
3948 VM_BUG_ON_PAGE(page_mapped(page
), page
);
3949 VM_BUG_ON_PAGE(page
->mapping
&& !PageAnon(page
), page
);
3951 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
3952 MEM_CGROUP_CHARGE_TYPE_ANON
);
3956 * While swap-in, try_charge -> commit or cancel, the page is locked.
3957 * And when try_charge() successfully returns, one refcnt to memcg without
3958 * struct page_cgroup is acquired. This refcnt will be consumed by
3959 * "commit()" or removed by "cancel()"
3961 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
3964 struct mem_cgroup
**memcgp
)
3966 struct mem_cgroup
*memcg
;
3967 struct page_cgroup
*pc
;
3970 pc
= lookup_page_cgroup(page
);
3972 * Every swap fault against a single page tries to charge the
3973 * page, bail as early as possible. shmem_unuse() encounters
3974 * already charged pages, too. The USED bit is protected by
3975 * the page lock, which serializes swap cache removal, which
3976 * in turn serializes uncharging.
3978 if (PageCgroupUsed(pc
))
3980 if (!do_swap_account
)
3982 memcg
= try_get_mem_cgroup_from_page(page
);
3986 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
3987 css_put(&memcg
->css
);
3992 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
3998 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
3999 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
4002 if (mem_cgroup_disabled())
4005 * A racing thread's fault, or swapoff, may have already
4006 * updated the pte, and even removed page from swap cache: in
4007 * those cases unuse_pte()'s pte_same() test will fail; but
4008 * there's also a KSM case which does need to charge the page.
4010 if (!PageSwapCache(page
)) {
4013 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
4018 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
4021 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
4023 if (mem_cgroup_disabled())
4027 __mem_cgroup_cancel_charge(memcg
, 1);
4031 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
4032 enum charge_type ctype
)
4034 if (mem_cgroup_disabled())
4039 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
4041 * Now swap is on-memory. This means this page may be
4042 * counted both as mem and swap....double count.
4043 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
4044 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
4045 * may call delete_from_swap_cache() before reach here.
4047 if (do_swap_account
&& PageSwapCache(page
)) {
4048 swp_entry_t ent
= {.val
= page_private(page
)};
4049 mem_cgroup_uncharge_swap(ent
);
4053 void mem_cgroup_commit_charge_swapin(struct page
*page
,
4054 struct mem_cgroup
*memcg
)
4056 __mem_cgroup_commit_charge_swapin(page
, memcg
,
4057 MEM_CGROUP_CHARGE_TYPE_ANON
);
4060 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
4063 struct mem_cgroup
*memcg
= NULL
;
4064 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4067 if (mem_cgroup_disabled())
4069 if (PageCompound(page
))
4072 if (!PageSwapCache(page
))
4073 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
4074 else { /* page is swapcache/shmem */
4075 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
4078 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
4083 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
4084 unsigned int nr_pages
,
4085 const enum charge_type ctype
)
4087 struct memcg_batch_info
*batch
= NULL
;
4088 bool uncharge_memsw
= true;
4090 /* If swapout, usage of swap doesn't decrease */
4091 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
4092 uncharge_memsw
= false;
4094 batch
= ¤t
->memcg_batch
;
4096 * In usual, we do css_get() when we remember memcg pointer.
4097 * But in this case, we keep res->usage until end of a series of
4098 * uncharges. Then, it's ok to ignore memcg's refcnt.
4101 batch
->memcg
= memcg
;
4103 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
4104 * In those cases, all pages freed continuously can be expected to be in
4105 * the same cgroup and we have chance to coalesce uncharges.
4106 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
4107 * because we want to do uncharge as soon as possible.
4110 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
4111 goto direct_uncharge
;
4114 goto direct_uncharge
;
4117 * In typical case, batch->memcg == mem. This means we can
4118 * merge a series of uncharges to an uncharge of res_counter.
4119 * If not, we uncharge res_counter ony by one.
4121 if (batch
->memcg
!= memcg
)
4122 goto direct_uncharge
;
4123 /* remember freed charge and uncharge it later */
4126 batch
->memsw_nr_pages
++;
4129 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
4131 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
4132 if (unlikely(batch
->memcg
!= memcg
))
4133 memcg_oom_recover(memcg
);
4137 * uncharge if !page_mapped(page)
4139 static struct mem_cgroup
*
4140 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
4143 struct mem_cgroup
*memcg
= NULL
;
4144 unsigned int nr_pages
= 1;
4145 struct page_cgroup
*pc
;
4148 if (mem_cgroup_disabled())
4151 if (PageTransHuge(page
)) {
4152 nr_pages
<<= compound_order(page
);
4153 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
4156 * Check if our page_cgroup is valid
4158 pc
= lookup_page_cgroup(page
);
4159 if (unlikely(!PageCgroupUsed(pc
)))
4162 lock_page_cgroup(pc
);
4164 memcg
= pc
->mem_cgroup
;
4166 if (!PageCgroupUsed(pc
))
4169 anon
= PageAnon(page
);
4172 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4174 * Generally PageAnon tells if it's the anon statistics to be
4175 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4176 * used before page reached the stage of being marked PageAnon.
4180 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4181 /* See mem_cgroup_prepare_migration() */
4182 if (page_mapped(page
))
4185 * Pages under migration may not be uncharged. But
4186 * end_migration() /must/ be the one uncharging the
4187 * unused post-migration page and so it has to call
4188 * here with the migration bit still set. See the
4189 * res_counter handling below.
4191 if (!end_migration
&& PageCgroupMigration(pc
))
4194 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4195 if (!PageAnon(page
)) { /* Shared memory */
4196 if (page
->mapping
&& !page_is_file_cache(page
))
4198 } else if (page_mapped(page
)) /* Anon */
4205 mem_cgroup_charge_statistics(memcg
, page
, anon
, -nr_pages
);
4207 ClearPageCgroupUsed(pc
);
4209 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4210 * freed from LRU. This is safe because uncharged page is expected not
4211 * to be reused (freed soon). Exception is SwapCache, it's handled by
4212 * special functions.
4215 unlock_page_cgroup(pc
);
4217 * even after unlock, we have memcg->res.usage here and this memcg
4218 * will never be freed, so it's safe to call css_get().
4220 memcg_check_events(memcg
, page
);
4221 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4222 mem_cgroup_swap_statistics(memcg
, true);
4223 css_get(&memcg
->css
);
4226 * Migration does not charge the res_counter for the
4227 * replacement page, so leave it alone when phasing out the
4228 * page that is unused after the migration.
4230 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4231 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4236 unlock_page_cgroup(pc
);
4240 void mem_cgroup_uncharge_page(struct page
*page
)
4243 if (page_mapped(page
))
4245 VM_BUG_ON_PAGE(page
->mapping
&& !PageAnon(page
), page
);
4247 * If the page is in swap cache, uncharge should be deferred
4248 * to the swap path, which also properly accounts swap usage
4249 * and handles memcg lifetime.
4251 * Note that this check is not stable and reclaim may add the
4252 * page to swap cache at any time after this. However, if the
4253 * page is not in swap cache by the time page->mapcount hits
4254 * 0, there won't be any page table references to the swap
4255 * slot, and reclaim will free it and not actually write the
4258 if (PageSwapCache(page
))
4260 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4263 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4265 VM_BUG_ON_PAGE(page_mapped(page
), page
);
4266 VM_BUG_ON_PAGE(page
->mapping
, page
);
4267 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4271 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4272 * In that cases, pages are freed continuously and we can expect pages
4273 * are in the same memcg. All these calls itself limits the number of
4274 * pages freed at once, then uncharge_start/end() is called properly.
4275 * This may be called prural(2) times in a context,
4278 void mem_cgroup_uncharge_start(void)
4280 current
->memcg_batch
.do_batch
++;
4281 /* We can do nest. */
4282 if (current
->memcg_batch
.do_batch
== 1) {
4283 current
->memcg_batch
.memcg
= NULL
;
4284 current
->memcg_batch
.nr_pages
= 0;
4285 current
->memcg_batch
.memsw_nr_pages
= 0;
4289 void mem_cgroup_uncharge_end(void)
4291 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4293 if (!batch
->do_batch
)
4297 if (batch
->do_batch
) /* If stacked, do nothing. */
4303 * This "batch->memcg" is valid without any css_get/put etc...
4304 * bacause we hide charges behind us.
4306 if (batch
->nr_pages
)
4307 res_counter_uncharge(&batch
->memcg
->res
,
4308 batch
->nr_pages
* PAGE_SIZE
);
4309 if (batch
->memsw_nr_pages
)
4310 res_counter_uncharge(&batch
->memcg
->memsw
,
4311 batch
->memsw_nr_pages
* PAGE_SIZE
);
4312 memcg_oom_recover(batch
->memcg
);
4313 /* forget this pointer (for sanity check) */
4314 batch
->memcg
= NULL
;
4319 * called after __delete_from_swap_cache() and drop "page" account.
4320 * memcg information is recorded to swap_cgroup of "ent"
4323 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4325 struct mem_cgroup
*memcg
;
4326 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4328 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4329 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4331 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4334 * record memcg information, if swapout && memcg != NULL,
4335 * css_get() was called in uncharge().
4337 if (do_swap_account
&& swapout
&& memcg
)
4338 swap_cgroup_record(ent
, mem_cgroup_id(memcg
));
4342 #ifdef CONFIG_MEMCG_SWAP
4344 * called from swap_entry_free(). remove record in swap_cgroup and
4345 * uncharge "memsw" account.
4347 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4349 struct mem_cgroup
*memcg
;
4352 if (!do_swap_account
)
4355 id
= swap_cgroup_record(ent
, 0);
4357 memcg
= mem_cgroup_lookup(id
);
4360 * We uncharge this because swap is freed.
4361 * This memcg can be obsolete one. We avoid calling css_tryget
4363 if (!mem_cgroup_is_root(memcg
))
4364 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4365 mem_cgroup_swap_statistics(memcg
, false);
4366 css_put(&memcg
->css
);
4372 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4373 * @entry: swap entry to be moved
4374 * @from: mem_cgroup which the entry is moved from
4375 * @to: mem_cgroup which the entry is moved to
4377 * It succeeds only when the swap_cgroup's record for this entry is the same
4378 * as the mem_cgroup's id of @from.
4380 * Returns 0 on success, -EINVAL on failure.
4382 * The caller must have charged to @to, IOW, called res_counter_charge() about
4383 * both res and memsw, and called css_get().
4385 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4386 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4388 unsigned short old_id
, new_id
;
4390 old_id
= mem_cgroup_id(from
);
4391 new_id
= mem_cgroup_id(to
);
4393 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4394 mem_cgroup_swap_statistics(from
, false);
4395 mem_cgroup_swap_statistics(to
, true);
4397 * This function is only called from task migration context now.
4398 * It postpones res_counter and refcount handling till the end
4399 * of task migration(mem_cgroup_clear_mc()) for performance
4400 * improvement. But we cannot postpone css_get(to) because if
4401 * the process that has been moved to @to does swap-in, the
4402 * refcount of @to might be decreased to 0.
4404 * We are in attach() phase, so the cgroup is guaranteed to be
4405 * alive, so we can just call css_get().
4413 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4414 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4421 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4424 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4425 struct mem_cgroup
**memcgp
)
4427 struct mem_cgroup
*memcg
= NULL
;
4428 unsigned int nr_pages
= 1;
4429 struct page_cgroup
*pc
;
4430 enum charge_type ctype
;
4434 if (mem_cgroup_disabled())
4437 if (PageTransHuge(page
))
4438 nr_pages
<<= compound_order(page
);
4440 pc
= lookup_page_cgroup(page
);
4441 lock_page_cgroup(pc
);
4442 if (PageCgroupUsed(pc
)) {
4443 memcg
= pc
->mem_cgroup
;
4444 css_get(&memcg
->css
);
4446 * At migrating an anonymous page, its mapcount goes down
4447 * to 0 and uncharge() will be called. But, even if it's fully
4448 * unmapped, migration may fail and this page has to be
4449 * charged again. We set MIGRATION flag here and delay uncharge
4450 * until end_migration() is called
4452 * Corner Case Thinking
4454 * When the old page was mapped as Anon and it's unmap-and-freed
4455 * while migration was ongoing.
4456 * If unmap finds the old page, uncharge() of it will be delayed
4457 * until end_migration(). If unmap finds a new page, it's
4458 * uncharged when it make mapcount to be 1->0. If unmap code
4459 * finds swap_migration_entry, the new page will not be mapped
4460 * and end_migration() will find it(mapcount==0).
4463 * When the old page was mapped but migraion fails, the kernel
4464 * remaps it. A charge for it is kept by MIGRATION flag even
4465 * if mapcount goes down to 0. We can do remap successfully
4466 * without charging it again.
4469 * The "old" page is under lock_page() until the end of
4470 * migration, so, the old page itself will not be swapped-out.
4471 * If the new page is swapped out before end_migraton, our
4472 * hook to usual swap-out path will catch the event.
4475 SetPageCgroupMigration(pc
);
4477 unlock_page_cgroup(pc
);
4479 * If the page is not charged at this point,
4487 * We charge new page before it's used/mapped. So, even if unlock_page()
4488 * is called before end_migration, we can catch all events on this new
4489 * page. In the case new page is migrated but not remapped, new page's
4490 * mapcount will be finally 0 and we call uncharge in end_migration().
4493 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4495 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4497 * The page is committed to the memcg, but it's not actually
4498 * charged to the res_counter since we plan on replacing the
4499 * old one and only one page is going to be left afterwards.
4501 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4504 /* remove redundant charge if migration failed*/
4505 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4506 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4508 struct page
*used
, *unused
;
4509 struct page_cgroup
*pc
;
4515 if (!migration_ok
) {
4522 anon
= PageAnon(used
);
4523 __mem_cgroup_uncharge_common(unused
,
4524 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4525 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4527 css_put(&memcg
->css
);
4529 * We disallowed uncharge of pages under migration because mapcount
4530 * of the page goes down to zero, temporarly.
4531 * Clear the flag and check the page should be charged.
4533 pc
= lookup_page_cgroup(oldpage
);
4534 lock_page_cgroup(pc
);
4535 ClearPageCgroupMigration(pc
);
4536 unlock_page_cgroup(pc
);
4539 * If a page is a file cache, radix-tree replacement is very atomic
4540 * and we can skip this check. When it was an Anon page, its mapcount
4541 * goes down to 0. But because we added MIGRATION flage, it's not
4542 * uncharged yet. There are several case but page->mapcount check
4543 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4544 * check. (see prepare_charge() also)
4547 mem_cgroup_uncharge_page(used
);
4551 * At replace page cache, newpage is not under any memcg but it's on
4552 * LRU. So, this function doesn't touch res_counter but handles LRU
4553 * in correct way. Both pages are locked so we cannot race with uncharge.
4555 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4556 struct page
*newpage
)
4558 struct mem_cgroup
*memcg
= NULL
;
4559 struct page_cgroup
*pc
;
4560 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4562 if (mem_cgroup_disabled())
4565 pc
= lookup_page_cgroup(oldpage
);
4566 /* fix accounting on old pages */
4567 lock_page_cgroup(pc
);
4568 if (PageCgroupUsed(pc
)) {
4569 memcg
= pc
->mem_cgroup
;
4570 mem_cgroup_charge_statistics(memcg
, oldpage
, false, -1);
4571 ClearPageCgroupUsed(pc
);
4573 unlock_page_cgroup(pc
);
4576 * When called from shmem_replace_page(), in some cases the
4577 * oldpage has already been charged, and in some cases not.
4582 * Even if newpage->mapping was NULL before starting replacement,
4583 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4584 * LRU while we overwrite pc->mem_cgroup.
4586 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4589 #ifdef CONFIG_DEBUG_VM
4590 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4592 struct page_cgroup
*pc
;
4594 pc
= lookup_page_cgroup(page
);
4596 * Can be NULL while feeding pages into the page allocator for
4597 * the first time, i.e. during boot or memory hotplug;
4598 * or when mem_cgroup_disabled().
4600 if (likely(pc
) && PageCgroupUsed(pc
))
4605 bool mem_cgroup_bad_page_check(struct page
*page
)
4607 if (mem_cgroup_disabled())
4610 return lookup_page_cgroup_used(page
) != NULL
;
4613 void mem_cgroup_print_bad_page(struct page
*page
)
4615 struct page_cgroup
*pc
;
4617 pc
= lookup_page_cgroup_used(page
);
4619 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4620 pc
, pc
->flags
, pc
->mem_cgroup
);
4625 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4626 unsigned long long val
)
4629 u64 memswlimit
, memlimit
;
4631 int children
= mem_cgroup_count_children(memcg
);
4632 u64 curusage
, oldusage
;
4636 * For keeping hierarchical_reclaim simple, how long we should retry
4637 * is depends on callers. We set our retry-count to be function
4638 * of # of children which we should visit in this loop.
4640 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4642 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4645 while (retry_count
) {
4646 if (signal_pending(current
)) {
4651 * Rather than hide all in some function, I do this in
4652 * open coded manner. You see what this really does.
4653 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4655 mutex_lock(&set_limit_mutex
);
4656 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4657 if (memswlimit
< val
) {
4659 mutex_unlock(&set_limit_mutex
);
4663 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4667 ret
= res_counter_set_limit(&memcg
->res
, val
);
4669 if (memswlimit
== val
)
4670 memcg
->memsw_is_minimum
= true;
4672 memcg
->memsw_is_minimum
= false;
4674 mutex_unlock(&set_limit_mutex
);
4679 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4680 MEM_CGROUP_RECLAIM_SHRINK
);
4681 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4682 /* Usage is reduced ? */
4683 if (curusage
>= oldusage
)
4686 oldusage
= curusage
;
4688 if (!ret
&& enlarge
)
4689 memcg_oom_recover(memcg
);
4694 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4695 unsigned long long val
)
4698 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4699 int children
= mem_cgroup_count_children(memcg
);
4703 /* see mem_cgroup_resize_res_limit */
4704 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4705 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4706 while (retry_count
) {
4707 if (signal_pending(current
)) {
4712 * Rather than hide all in some function, I do this in
4713 * open coded manner. You see what this really does.
4714 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4716 mutex_lock(&set_limit_mutex
);
4717 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4718 if (memlimit
> val
) {
4720 mutex_unlock(&set_limit_mutex
);
4723 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4724 if (memswlimit
< val
)
4726 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4728 if (memlimit
== val
)
4729 memcg
->memsw_is_minimum
= true;
4731 memcg
->memsw_is_minimum
= false;
4733 mutex_unlock(&set_limit_mutex
);
4738 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4739 MEM_CGROUP_RECLAIM_NOSWAP
|
4740 MEM_CGROUP_RECLAIM_SHRINK
);
4741 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4742 /* Usage is reduced ? */
4743 if (curusage
>= oldusage
)
4746 oldusage
= curusage
;
4748 if (!ret
&& enlarge
)
4749 memcg_oom_recover(memcg
);
4753 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
4755 unsigned long *total_scanned
)
4757 unsigned long nr_reclaimed
= 0;
4758 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
4759 unsigned long reclaimed
;
4761 struct mem_cgroup_tree_per_zone
*mctz
;
4762 unsigned long long excess
;
4763 unsigned long nr_scanned
;
4768 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
4770 * This loop can run a while, specially if mem_cgroup's continuously
4771 * keep exceeding their soft limit and putting the system under
4778 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
4783 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
4784 gfp_mask
, &nr_scanned
);
4785 nr_reclaimed
+= reclaimed
;
4786 *total_scanned
+= nr_scanned
;
4787 spin_lock(&mctz
->lock
);
4790 * If we failed to reclaim anything from this memory cgroup
4791 * it is time to move on to the next cgroup
4797 * Loop until we find yet another one.
4799 * By the time we get the soft_limit lock
4800 * again, someone might have aded the
4801 * group back on the RB tree. Iterate to
4802 * make sure we get a different mem.
4803 * mem_cgroup_largest_soft_limit_node returns
4804 * NULL if no other cgroup is present on
4808 __mem_cgroup_largest_soft_limit_node(mctz
);
4810 css_put(&next_mz
->memcg
->css
);
4811 else /* next_mz == NULL or other memcg */
4815 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
4816 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
4818 * One school of thought says that we should not add
4819 * back the node to the tree if reclaim returns 0.
4820 * But our reclaim could return 0, simply because due
4821 * to priority we are exposing a smaller subset of
4822 * memory to reclaim from. Consider this as a longer
4825 /* If excess == 0, no tree ops */
4826 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
4827 spin_unlock(&mctz
->lock
);
4828 css_put(&mz
->memcg
->css
);
4831 * Could not reclaim anything and there are no more
4832 * mem cgroups to try or we seem to be looping without
4833 * reclaiming anything.
4835 if (!nr_reclaimed
&&
4837 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
4839 } while (!nr_reclaimed
);
4841 css_put(&next_mz
->memcg
->css
);
4842 return nr_reclaimed
;
4846 * mem_cgroup_force_empty_list - clears LRU of a group
4847 * @memcg: group to clear
4850 * @lru: lru to to clear
4852 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4853 * reclaim the pages page themselves - pages are moved to the parent (or root)
4856 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4857 int node
, int zid
, enum lru_list lru
)
4859 struct lruvec
*lruvec
;
4860 unsigned long flags
;
4861 struct list_head
*list
;
4865 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4866 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4867 list
= &lruvec
->lists
[lru
];
4871 struct page_cgroup
*pc
;
4874 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4875 if (list_empty(list
)) {
4876 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4879 page
= list_entry(list
->prev
, struct page
, lru
);
4881 list_move(&page
->lru
, list
);
4883 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4886 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4888 pc
= lookup_page_cgroup(page
);
4890 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4891 /* found lock contention or "pc" is obsolete. */
4896 } while (!list_empty(list
));
4900 * make mem_cgroup's charge to be 0 if there is no task by moving
4901 * all the charges and pages to the parent.
4902 * This enables deleting this mem_cgroup.
4904 * Caller is responsible for holding css reference on the memcg.
4906 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4912 /* This is for making all *used* pages to be on LRU. */
4913 lru_add_drain_all();
4914 drain_all_stock_sync(memcg
);
4915 mem_cgroup_start_move(memcg
);
4916 for_each_node_state(node
, N_MEMORY
) {
4917 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4920 mem_cgroup_force_empty_list(memcg
,
4925 mem_cgroup_end_move(memcg
);
4926 memcg_oom_recover(memcg
);
4930 * Kernel memory may not necessarily be trackable to a specific
4931 * process. So they are not migrated, and therefore we can't
4932 * expect their value to drop to 0 here.
4933 * Having res filled up with kmem only is enough.
4935 * This is a safety check because mem_cgroup_force_empty_list
4936 * could have raced with mem_cgroup_replace_page_cache callers
4937 * so the lru seemed empty but the page could have been added
4938 * right after the check. RES_USAGE should be safe as we always
4939 * charge before adding to the LRU.
4941 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
4942 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
4943 } while (usage
> 0);
4946 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
4948 lockdep_assert_held(&memcg_create_mutex
);
4950 * The lock does not prevent addition or deletion to the list
4951 * of children, but it prevents a new child from being
4952 * initialized based on this parent in css_online(), so it's
4953 * enough to decide whether hierarchically inherited
4954 * attributes can still be changed or not.
4956 return memcg
->use_hierarchy
&&
4957 !list_empty(&memcg
->css
.cgroup
->children
);
4961 * Reclaims as many pages from the given memcg as possible and moves
4962 * the rest to the parent.
4964 * Caller is responsible for holding css reference for memcg.
4966 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
4968 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
4969 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
4971 /* returns EBUSY if there is a task or if we come here twice. */
4972 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
4975 /* we call try-to-free pages for make this cgroup empty */
4976 lru_add_drain_all();
4977 /* try to free all pages in this cgroup */
4978 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
4981 if (signal_pending(current
))
4984 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
4988 /* maybe some writeback is necessary */
4989 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
4994 mem_cgroup_reparent_charges(memcg
);
4999 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state
*css
,
5002 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5004 if (mem_cgroup_is_root(memcg
))
5006 return mem_cgroup_force_empty(memcg
);
5009 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
5012 return mem_cgroup_from_css(css
)->use_hierarchy
;
5015 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
5016 struct cftype
*cft
, u64 val
)
5019 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5020 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5022 mutex_lock(&memcg_create_mutex
);
5024 if (memcg
->use_hierarchy
== val
)
5028 * If parent's use_hierarchy is set, we can't make any modifications
5029 * in the child subtrees. If it is unset, then the change can
5030 * occur, provided the current cgroup has no children.
5032 * For the root cgroup, parent_mem is NULL, we allow value to be
5033 * set if there are no children.
5035 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
5036 (val
== 1 || val
== 0)) {
5037 if (list_empty(&memcg
->css
.cgroup
->children
))
5038 memcg
->use_hierarchy
= val
;
5045 mutex_unlock(&memcg_create_mutex
);
5051 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
5052 enum mem_cgroup_stat_index idx
)
5054 struct mem_cgroup
*iter
;
5057 /* Per-cpu values can be negative, use a signed accumulator */
5058 for_each_mem_cgroup_tree(iter
, memcg
)
5059 val
+= mem_cgroup_read_stat(iter
, idx
);
5061 if (val
< 0) /* race ? */
5066 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
5070 if (!mem_cgroup_is_root(memcg
)) {
5072 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
5074 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
5078 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
5079 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
5081 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
5082 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
5085 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
5087 return val
<< PAGE_SHIFT
;
5090 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
5093 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5098 type
= MEMFILE_TYPE(cft
->private);
5099 name
= MEMFILE_ATTR(cft
->private);
5103 if (name
== RES_USAGE
)
5104 val
= mem_cgroup_usage(memcg
, false);
5106 val
= res_counter_read_u64(&memcg
->res
, name
);
5109 if (name
== RES_USAGE
)
5110 val
= mem_cgroup_usage(memcg
, true);
5112 val
= res_counter_read_u64(&memcg
->memsw
, name
);
5115 val
= res_counter_read_u64(&memcg
->kmem
, name
);
5124 #ifdef CONFIG_MEMCG_KMEM
5125 /* should be called with activate_kmem_mutex held */
5126 static int __memcg_activate_kmem(struct mem_cgroup
*memcg
,
5127 unsigned long long limit
)
5132 if (memcg_kmem_is_active(memcg
))
5136 * We are going to allocate memory for data shared by all memory
5137 * cgroups so let's stop accounting here.
5139 memcg_stop_kmem_account();
5142 * For simplicity, we won't allow this to be disabled. It also can't
5143 * be changed if the cgroup has children already, or if tasks had
5146 * If tasks join before we set the limit, a person looking at
5147 * kmem.usage_in_bytes will have no way to determine when it took
5148 * place, which makes the value quite meaningless.
5150 * After it first became limited, changes in the value of the limit are
5151 * of course permitted.
5153 mutex_lock(&memcg_create_mutex
);
5154 if (cgroup_task_count(memcg
->css
.cgroup
) || memcg_has_children(memcg
))
5156 mutex_unlock(&memcg_create_mutex
);
5160 memcg_id
= ida_simple_get(&kmem_limited_groups
,
5161 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
5168 * Make sure we have enough space for this cgroup in each root cache's
5171 err
= memcg_update_all_caches(memcg_id
+ 1);
5175 memcg
->kmemcg_id
= memcg_id
;
5176 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
5177 mutex_init(&memcg
->slab_caches_mutex
);
5180 * We couldn't have accounted to this cgroup, because it hasn't got the
5181 * active bit set yet, so this should succeed.
5183 err
= res_counter_set_limit(&memcg
->kmem
, limit
);
5186 static_key_slow_inc(&memcg_kmem_enabled_key
);
5188 * Setting the active bit after enabling static branching will
5189 * guarantee no one starts accounting before all call sites are
5192 memcg_kmem_set_active(memcg
);
5194 memcg_resume_kmem_account();
5198 ida_simple_remove(&kmem_limited_groups
, memcg_id
);
5202 static int memcg_activate_kmem(struct mem_cgroup
*memcg
,
5203 unsigned long long limit
)
5207 mutex_lock(&activate_kmem_mutex
);
5208 ret
= __memcg_activate_kmem(memcg
, limit
);
5209 mutex_unlock(&activate_kmem_mutex
);
5213 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
5214 unsigned long long val
)
5218 if (!memcg_kmem_is_active(memcg
))
5219 ret
= memcg_activate_kmem(memcg
, val
);
5221 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5225 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5228 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5233 mutex_lock(&activate_kmem_mutex
);
5235 * If the parent cgroup is not kmem-active now, it cannot be activated
5236 * after this point, because it has at least one child already.
5238 if (memcg_kmem_is_active(parent
))
5239 ret
= __memcg_activate_kmem(memcg
, RES_COUNTER_MAX
);
5240 mutex_unlock(&activate_kmem_mutex
);
5244 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
5245 unsigned long long val
)
5249 #endif /* CONFIG_MEMCG_KMEM */
5252 * The user of this function is...
5255 static int mem_cgroup_write(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
5258 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5261 unsigned long long val
;
5264 type
= MEMFILE_TYPE(cft
->private);
5265 name
= MEMFILE_ATTR(cft
->private);
5269 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5273 /* This function does all necessary parse...reuse it */
5274 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5278 ret
= mem_cgroup_resize_limit(memcg
, val
);
5279 else if (type
== _MEMSWAP
)
5280 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5281 else if (type
== _KMEM
)
5282 ret
= memcg_update_kmem_limit(memcg
, val
);
5286 case RES_SOFT_LIMIT
:
5287 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5291 * For memsw, soft limits are hard to implement in terms
5292 * of semantics, for now, we support soft limits for
5293 * control without swap
5296 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5301 ret
= -EINVAL
; /* should be BUG() ? */
5307 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5308 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5310 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5312 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5313 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5314 if (!memcg
->use_hierarchy
)
5317 while (css_parent(&memcg
->css
)) {
5318 memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5319 if (!memcg
->use_hierarchy
)
5321 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5322 min_limit
= min(min_limit
, tmp
);
5323 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5324 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5327 *mem_limit
= min_limit
;
5328 *memsw_limit
= min_memsw_limit
;
5331 static int mem_cgroup_reset(struct cgroup_subsys_state
*css
, unsigned int event
)
5333 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5337 type
= MEMFILE_TYPE(event
);
5338 name
= MEMFILE_ATTR(event
);
5343 res_counter_reset_max(&memcg
->res
);
5344 else if (type
== _MEMSWAP
)
5345 res_counter_reset_max(&memcg
->memsw
);
5346 else if (type
== _KMEM
)
5347 res_counter_reset_max(&memcg
->kmem
);
5353 res_counter_reset_failcnt(&memcg
->res
);
5354 else if (type
== _MEMSWAP
)
5355 res_counter_reset_failcnt(&memcg
->memsw
);
5356 else if (type
== _KMEM
)
5357 res_counter_reset_failcnt(&memcg
->kmem
);
5366 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
5369 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
5373 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5374 struct cftype
*cft
, u64 val
)
5376 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5378 if (val
>= (1 << NR_MOVE_TYPE
))
5382 * No kind of locking is needed in here, because ->can_attach() will
5383 * check this value once in the beginning of the process, and then carry
5384 * on with stale data. This means that changes to this value will only
5385 * affect task migrations starting after the change.
5387 memcg
->move_charge_at_immigrate
= val
;
5391 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5392 struct cftype
*cft
, u64 val
)
5399 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
5403 unsigned int lru_mask
;
5406 static const struct numa_stat stats
[] = {
5407 { "total", LRU_ALL
},
5408 { "file", LRU_ALL_FILE
},
5409 { "anon", LRU_ALL_ANON
},
5410 { "unevictable", BIT(LRU_UNEVICTABLE
) },
5412 const struct numa_stat
*stat
;
5415 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5417 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5418 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
5419 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
5420 for_each_node_state(nid
, N_MEMORY
) {
5421 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5423 seq_printf(m
, " N%d=%lu", nid
, nr
);
5428 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5429 struct mem_cgroup
*iter
;
5432 for_each_mem_cgroup_tree(iter
, memcg
)
5433 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
5434 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
5435 for_each_node_state(nid
, N_MEMORY
) {
5437 for_each_mem_cgroup_tree(iter
, memcg
)
5438 nr
+= mem_cgroup_node_nr_lru_pages(
5439 iter
, nid
, stat
->lru_mask
);
5440 seq_printf(m
, " N%d=%lu", nid
, nr
);
5447 #endif /* CONFIG_NUMA */
5449 static inline void mem_cgroup_lru_names_not_uptodate(void)
5451 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5454 static int memcg_stat_show(struct seq_file
*m
, void *v
)
5456 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5457 struct mem_cgroup
*mi
;
5460 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5461 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5463 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5464 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5467 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5468 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5469 mem_cgroup_read_events(memcg
, i
));
5471 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5472 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5473 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5475 /* Hierarchical information */
5477 unsigned long long limit
, memsw_limit
;
5478 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5479 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5480 if (do_swap_account
)
5481 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5485 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5488 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5490 for_each_mem_cgroup_tree(mi
, memcg
)
5491 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5492 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5495 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5496 unsigned long long val
= 0;
5498 for_each_mem_cgroup_tree(mi
, memcg
)
5499 val
+= mem_cgroup_read_events(mi
, i
);
5500 seq_printf(m
, "total_%s %llu\n",
5501 mem_cgroup_events_names
[i
], val
);
5504 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5505 unsigned long long val
= 0;
5507 for_each_mem_cgroup_tree(mi
, memcg
)
5508 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5509 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5512 #ifdef CONFIG_DEBUG_VM
5515 struct mem_cgroup_per_zone
*mz
;
5516 struct zone_reclaim_stat
*rstat
;
5517 unsigned long recent_rotated
[2] = {0, 0};
5518 unsigned long recent_scanned
[2] = {0, 0};
5520 for_each_online_node(nid
)
5521 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5522 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5523 rstat
= &mz
->lruvec
.reclaim_stat
;
5525 recent_rotated
[0] += rstat
->recent_rotated
[0];
5526 recent_rotated
[1] += rstat
->recent_rotated
[1];
5527 recent_scanned
[0] += rstat
->recent_scanned
[0];
5528 recent_scanned
[1] += rstat
->recent_scanned
[1];
5530 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5531 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5532 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5533 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5540 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
5543 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5545 return mem_cgroup_swappiness(memcg
);
5548 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
5549 struct cftype
*cft
, u64 val
)
5551 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5552 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5554 if (val
> 100 || !parent
)
5557 mutex_lock(&memcg_create_mutex
);
5559 /* If under hierarchy, only empty-root can set this value */
5560 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5561 mutex_unlock(&memcg_create_mutex
);
5565 memcg
->swappiness
= val
;
5567 mutex_unlock(&memcg_create_mutex
);
5572 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5574 struct mem_cgroup_threshold_ary
*t
;
5580 t
= rcu_dereference(memcg
->thresholds
.primary
);
5582 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5587 usage
= mem_cgroup_usage(memcg
, swap
);
5590 * current_threshold points to threshold just below or equal to usage.
5591 * If it's not true, a threshold was crossed after last
5592 * call of __mem_cgroup_threshold().
5594 i
= t
->current_threshold
;
5597 * Iterate backward over array of thresholds starting from
5598 * current_threshold and check if a threshold is crossed.
5599 * If none of thresholds below usage is crossed, we read
5600 * only one element of the array here.
5602 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5603 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5605 /* i = current_threshold + 1 */
5609 * Iterate forward over array of thresholds starting from
5610 * current_threshold+1 and check if a threshold is crossed.
5611 * If none of thresholds above usage is crossed, we read
5612 * only one element of the array here.
5614 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5615 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5617 /* Update current_threshold */
5618 t
->current_threshold
= i
- 1;
5623 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5626 __mem_cgroup_threshold(memcg
, false);
5627 if (do_swap_account
)
5628 __mem_cgroup_threshold(memcg
, true);
5630 memcg
= parent_mem_cgroup(memcg
);
5634 static int compare_thresholds(const void *a
, const void *b
)
5636 const struct mem_cgroup_threshold
*_a
= a
;
5637 const struct mem_cgroup_threshold
*_b
= b
;
5639 if (_a
->threshold
> _b
->threshold
)
5642 if (_a
->threshold
< _b
->threshold
)
5648 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5650 struct mem_cgroup_eventfd_list
*ev
;
5652 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5653 eventfd_signal(ev
->eventfd
, 1);
5657 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5659 struct mem_cgroup
*iter
;
5661 for_each_mem_cgroup_tree(iter
, memcg
)
5662 mem_cgroup_oom_notify_cb(iter
);
5665 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5666 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
5668 struct mem_cgroup_thresholds
*thresholds
;
5669 struct mem_cgroup_threshold_ary
*new;
5670 u64 threshold
, usage
;
5673 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5677 mutex_lock(&memcg
->thresholds_lock
);
5680 thresholds
= &memcg
->thresholds
;
5681 else if (type
== _MEMSWAP
)
5682 thresholds
= &memcg
->memsw_thresholds
;
5686 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5688 /* Check if a threshold crossed before adding a new one */
5689 if (thresholds
->primary
)
5690 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5692 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5694 /* Allocate memory for new array of thresholds */
5695 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5703 /* Copy thresholds (if any) to new array */
5704 if (thresholds
->primary
) {
5705 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5706 sizeof(struct mem_cgroup_threshold
));
5709 /* Add new threshold */
5710 new->entries
[size
- 1].eventfd
= eventfd
;
5711 new->entries
[size
- 1].threshold
= threshold
;
5713 /* Sort thresholds. Registering of new threshold isn't time-critical */
5714 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5715 compare_thresholds
, NULL
);
5717 /* Find current threshold */
5718 new->current_threshold
= -1;
5719 for (i
= 0; i
< size
; i
++) {
5720 if (new->entries
[i
].threshold
<= usage
) {
5722 * new->current_threshold will not be used until
5723 * rcu_assign_pointer(), so it's safe to increment
5726 ++new->current_threshold
;
5731 /* Free old spare buffer and save old primary buffer as spare */
5732 kfree(thresholds
->spare
);
5733 thresholds
->spare
= thresholds
->primary
;
5735 rcu_assign_pointer(thresholds
->primary
, new);
5737 /* To be sure that nobody uses thresholds */
5741 mutex_unlock(&memcg
->thresholds_lock
);
5746 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5747 struct eventfd_ctx
*eventfd
, const char *args
)
5749 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
5752 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5753 struct eventfd_ctx
*eventfd
, const char *args
)
5755 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
5758 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5759 struct eventfd_ctx
*eventfd
, enum res_type type
)
5761 struct mem_cgroup_thresholds
*thresholds
;
5762 struct mem_cgroup_threshold_ary
*new;
5766 mutex_lock(&memcg
->thresholds_lock
);
5768 thresholds
= &memcg
->thresholds
;
5769 else if (type
== _MEMSWAP
)
5770 thresholds
= &memcg
->memsw_thresholds
;
5774 if (!thresholds
->primary
)
5777 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5779 /* Check if a threshold crossed before removing */
5780 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5782 /* Calculate new number of threshold */
5784 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5785 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5789 new = thresholds
->spare
;
5791 /* Set thresholds array to NULL if we don't have thresholds */
5800 /* Copy thresholds and find current threshold */
5801 new->current_threshold
= -1;
5802 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5803 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5806 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5807 if (new->entries
[j
].threshold
<= usage
) {
5809 * new->current_threshold will not be used
5810 * until rcu_assign_pointer(), so it's safe to increment
5813 ++new->current_threshold
;
5819 /* Swap primary and spare array */
5820 thresholds
->spare
= thresholds
->primary
;
5821 /* If all events are unregistered, free the spare array */
5823 kfree(thresholds
->spare
);
5824 thresholds
->spare
= NULL
;
5827 rcu_assign_pointer(thresholds
->primary
, new);
5829 /* To be sure that nobody uses thresholds */
5832 mutex_unlock(&memcg
->thresholds_lock
);
5835 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5836 struct eventfd_ctx
*eventfd
)
5838 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
5841 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5842 struct eventfd_ctx
*eventfd
)
5844 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
5847 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
5848 struct eventfd_ctx
*eventfd
, const char *args
)
5850 struct mem_cgroup_eventfd_list
*event
;
5852 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5856 spin_lock(&memcg_oom_lock
);
5858 event
->eventfd
= eventfd
;
5859 list_add(&event
->list
, &memcg
->oom_notify
);
5861 /* already in OOM ? */
5862 if (atomic_read(&memcg
->under_oom
))
5863 eventfd_signal(eventfd
, 1);
5864 spin_unlock(&memcg_oom_lock
);
5869 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
5870 struct eventfd_ctx
*eventfd
)
5872 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5874 spin_lock(&memcg_oom_lock
);
5876 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5877 if (ev
->eventfd
== eventfd
) {
5878 list_del(&ev
->list
);
5883 spin_unlock(&memcg_oom_lock
);
5886 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
5888 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
5890 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
5891 seq_printf(sf
, "under_oom %d\n", (bool)atomic_read(&memcg
->under_oom
));
5895 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
5896 struct cftype
*cft
, u64 val
)
5898 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5899 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5901 /* cannot set to root cgroup and only 0 and 1 are allowed */
5902 if (!parent
|| !((val
== 0) || (val
== 1)))
5905 mutex_lock(&memcg_create_mutex
);
5906 /* oom-kill-disable is a flag for subhierarchy. */
5907 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5908 mutex_unlock(&memcg_create_mutex
);
5911 memcg
->oom_kill_disable
= val
;
5913 memcg_oom_recover(memcg
);
5914 mutex_unlock(&memcg_create_mutex
);
5918 #ifdef CONFIG_MEMCG_KMEM
5919 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5923 memcg
->kmemcg_id
= -1;
5924 ret
= memcg_propagate_kmem(memcg
);
5928 return mem_cgroup_sockets_init(memcg
, ss
);
5931 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5933 mem_cgroup_sockets_destroy(memcg
);
5936 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5938 if (!memcg_kmem_is_active(memcg
))
5942 * kmem charges can outlive the cgroup. In the case of slab
5943 * pages, for instance, a page contain objects from various
5944 * processes. As we prevent from taking a reference for every
5945 * such allocation we have to be careful when doing uncharge
5946 * (see memcg_uncharge_kmem) and here during offlining.
5948 * The idea is that that only the _last_ uncharge which sees
5949 * the dead memcg will drop the last reference. An additional
5950 * reference is taken here before the group is marked dead
5951 * which is then paired with css_put during uncharge resp. here.
5953 * Although this might sound strange as this path is called from
5954 * css_offline() when the referencemight have dropped down to 0
5955 * and shouldn't be incremented anymore (css_tryget would fail)
5956 * we do not have other options because of the kmem allocations
5959 css_get(&memcg
->css
);
5961 memcg_kmem_mark_dead(memcg
);
5963 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5966 if (memcg_kmem_test_and_clear_dead(memcg
))
5967 css_put(&memcg
->css
);
5970 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5975 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5979 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5985 * DO NOT USE IN NEW FILES.
5987 * "cgroup.event_control" implementation.
5989 * This is way over-engineered. It tries to support fully configurable
5990 * events for each user. Such level of flexibility is completely
5991 * unnecessary especially in the light of the planned unified hierarchy.
5993 * Please deprecate this and replace with something simpler if at all
5998 * Unregister event and free resources.
6000 * Gets called from workqueue.
6002 static void memcg_event_remove(struct work_struct
*work
)
6004 struct mem_cgroup_event
*event
=
6005 container_of(work
, struct mem_cgroup_event
, remove
);
6006 struct mem_cgroup
*memcg
= event
->memcg
;
6008 remove_wait_queue(event
->wqh
, &event
->wait
);
6010 event
->unregister_event(memcg
, event
->eventfd
);
6012 /* Notify userspace the event is going away. */
6013 eventfd_signal(event
->eventfd
, 1);
6015 eventfd_ctx_put(event
->eventfd
);
6017 css_put(&memcg
->css
);
6021 * Gets called on POLLHUP on eventfd when user closes it.
6023 * Called with wqh->lock held and interrupts disabled.
6025 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
6026 int sync
, void *key
)
6028 struct mem_cgroup_event
*event
=
6029 container_of(wait
, struct mem_cgroup_event
, wait
);
6030 struct mem_cgroup
*memcg
= event
->memcg
;
6031 unsigned long flags
= (unsigned long)key
;
6033 if (flags
& POLLHUP
) {
6035 * If the event has been detached at cgroup removal, we
6036 * can simply return knowing the other side will cleanup
6039 * We can't race against event freeing since the other
6040 * side will require wqh->lock via remove_wait_queue(),
6043 spin_lock(&memcg
->event_list_lock
);
6044 if (!list_empty(&event
->list
)) {
6045 list_del_init(&event
->list
);
6047 * We are in atomic context, but cgroup_event_remove()
6048 * may sleep, so we have to call it in workqueue.
6050 schedule_work(&event
->remove
);
6052 spin_unlock(&memcg
->event_list_lock
);
6058 static void memcg_event_ptable_queue_proc(struct file
*file
,
6059 wait_queue_head_t
*wqh
, poll_table
*pt
)
6061 struct mem_cgroup_event
*event
=
6062 container_of(pt
, struct mem_cgroup_event
, pt
);
6065 add_wait_queue(wqh
, &event
->wait
);
6069 * DO NOT USE IN NEW FILES.
6071 * Parse input and register new cgroup event handler.
6073 * Input must be in format '<event_fd> <control_fd> <args>'.
6074 * Interpretation of args is defined by control file implementation.
6076 static int memcg_write_event_control(struct cgroup_subsys_state
*css
,
6077 struct cftype
*cft
, const char *buffer
)
6079 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6080 struct mem_cgroup_event
*event
;
6081 struct cgroup_subsys_state
*cfile_css
;
6082 unsigned int efd
, cfd
;
6089 efd
= simple_strtoul(buffer
, &endp
, 10);
6094 cfd
= simple_strtoul(buffer
, &endp
, 10);
6095 if ((*endp
!= ' ') && (*endp
!= '\0'))
6099 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6103 event
->memcg
= memcg
;
6104 INIT_LIST_HEAD(&event
->list
);
6105 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
6106 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
6107 INIT_WORK(&event
->remove
, memcg_event_remove
);
6115 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
6116 if (IS_ERR(event
->eventfd
)) {
6117 ret
= PTR_ERR(event
->eventfd
);
6124 goto out_put_eventfd
;
6127 /* the process need read permission on control file */
6128 /* AV: shouldn't we check that it's been opened for read instead? */
6129 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
6134 * Determine the event callbacks and set them in @event. This used
6135 * to be done via struct cftype but cgroup core no longer knows
6136 * about these events. The following is crude but the whole thing
6137 * is for compatibility anyway.
6139 * DO NOT ADD NEW FILES.
6141 name
= cfile
.file
->f_dentry
->d_name
.name
;
6143 if (!strcmp(name
, "memory.usage_in_bytes")) {
6144 event
->register_event
= mem_cgroup_usage_register_event
;
6145 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
6146 } else if (!strcmp(name
, "memory.oom_control")) {
6147 event
->register_event
= mem_cgroup_oom_register_event
;
6148 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
6149 } else if (!strcmp(name
, "memory.pressure_level")) {
6150 event
->register_event
= vmpressure_register_event
;
6151 event
->unregister_event
= vmpressure_unregister_event
;
6152 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
6153 event
->register_event
= memsw_cgroup_usage_register_event
;
6154 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
6161 * Verify @cfile should belong to @css. Also, remaining events are
6162 * automatically removed on cgroup destruction but the removal is
6163 * asynchronous, so take an extra ref on @css.
6168 cfile_css
= css_from_dir(cfile
.file
->f_dentry
->d_parent
,
6169 &mem_cgroup_subsys
);
6170 if (cfile_css
== css
&& css_tryget(css
))
6177 ret
= event
->register_event(memcg
, event
->eventfd
, buffer
);
6181 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
6183 spin_lock(&memcg
->event_list_lock
);
6184 list_add(&event
->list
, &memcg
->event_list
);
6185 spin_unlock(&memcg
->event_list_lock
);
6197 eventfd_ctx_put(event
->eventfd
);
6206 static struct cftype mem_cgroup_files
[] = {
6208 .name
= "usage_in_bytes",
6209 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
6210 .read_u64
= mem_cgroup_read_u64
,
6213 .name
= "max_usage_in_bytes",
6214 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
6215 .trigger
= mem_cgroup_reset
,
6216 .read_u64
= mem_cgroup_read_u64
,
6219 .name
= "limit_in_bytes",
6220 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
6221 .write_string
= mem_cgroup_write
,
6222 .read_u64
= mem_cgroup_read_u64
,
6225 .name
= "soft_limit_in_bytes",
6226 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
6227 .write_string
= mem_cgroup_write
,
6228 .read_u64
= mem_cgroup_read_u64
,
6232 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
6233 .trigger
= mem_cgroup_reset
,
6234 .read_u64
= mem_cgroup_read_u64
,
6238 .seq_show
= memcg_stat_show
,
6241 .name
= "force_empty",
6242 .trigger
= mem_cgroup_force_empty_write
,
6245 .name
= "use_hierarchy",
6246 .flags
= CFTYPE_INSANE
,
6247 .write_u64
= mem_cgroup_hierarchy_write
,
6248 .read_u64
= mem_cgroup_hierarchy_read
,
6251 .name
= "cgroup.event_control", /* XXX: for compat */
6252 .write_string
= memcg_write_event_control
,
6253 .flags
= CFTYPE_NO_PREFIX
,
6257 .name
= "swappiness",
6258 .read_u64
= mem_cgroup_swappiness_read
,
6259 .write_u64
= mem_cgroup_swappiness_write
,
6262 .name
= "move_charge_at_immigrate",
6263 .read_u64
= mem_cgroup_move_charge_read
,
6264 .write_u64
= mem_cgroup_move_charge_write
,
6267 .name
= "oom_control",
6268 .seq_show
= mem_cgroup_oom_control_read
,
6269 .write_u64
= mem_cgroup_oom_control_write
,
6270 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
6273 .name
= "pressure_level",
6277 .name
= "numa_stat",
6278 .seq_show
= memcg_numa_stat_show
,
6281 #ifdef CONFIG_MEMCG_KMEM
6283 .name
= "kmem.limit_in_bytes",
6284 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
6285 .write_string
= mem_cgroup_write
,
6286 .read_u64
= mem_cgroup_read_u64
,
6289 .name
= "kmem.usage_in_bytes",
6290 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
6291 .read_u64
= mem_cgroup_read_u64
,
6294 .name
= "kmem.failcnt",
6295 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
6296 .trigger
= mem_cgroup_reset
,
6297 .read_u64
= mem_cgroup_read_u64
,
6300 .name
= "kmem.max_usage_in_bytes",
6301 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
6302 .trigger
= mem_cgroup_reset
,
6303 .read_u64
= mem_cgroup_read_u64
,
6305 #ifdef CONFIG_SLABINFO
6307 .name
= "kmem.slabinfo",
6308 .seq_show
= mem_cgroup_slabinfo_read
,
6312 { }, /* terminate */
6315 #ifdef CONFIG_MEMCG_SWAP
6316 static struct cftype memsw_cgroup_files
[] = {
6318 .name
= "memsw.usage_in_bytes",
6319 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6320 .read_u64
= mem_cgroup_read_u64
,
6323 .name
= "memsw.max_usage_in_bytes",
6324 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6325 .trigger
= mem_cgroup_reset
,
6326 .read_u64
= mem_cgroup_read_u64
,
6329 .name
= "memsw.limit_in_bytes",
6330 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6331 .write_string
= mem_cgroup_write
,
6332 .read_u64
= mem_cgroup_read_u64
,
6335 .name
= "memsw.failcnt",
6336 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6337 .trigger
= mem_cgroup_reset
,
6338 .read_u64
= mem_cgroup_read_u64
,
6340 { }, /* terminate */
6343 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6345 struct mem_cgroup_per_node
*pn
;
6346 struct mem_cgroup_per_zone
*mz
;
6347 int zone
, tmp
= node
;
6349 * This routine is called against possible nodes.
6350 * But it's BUG to call kmalloc() against offline node.
6352 * TODO: this routine can waste much memory for nodes which will
6353 * never be onlined. It's better to use memory hotplug callback
6356 if (!node_state(node
, N_NORMAL_MEMORY
))
6358 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
6362 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6363 mz
= &pn
->zoneinfo
[zone
];
6364 lruvec_init(&mz
->lruvec
);
6365 mz
->usage_in_excess
= 0;
6366 mz
->on_tree
= false;
6369 memcg
->nodeinfo
[node
] = pn
;
6373 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6375 kfree(memcg
->nodeinfo
[node
]);
6378 static struct mem_cgroup
*mem_cgroup_alloc(void)
6380 struct mem_cgroup
*memcg
;
6383 size
= sizeof(struct mem_cgroup
);
6384 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
6386 memcg
= kzalloc(size
, GFP_KERNEL
);
6390 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
6393 spin_lock_init(&memcg
->pcp_counter_lock
);
6402 * At destroying mem_cgroup, references from swap_cgroup can remain.
6403 * (scanning all at force_empty is too costly...)
6405 * Instead of clearing all references at force_empty, we remember
6406 * the number of reference from swap_cgroup and free mem_cgroup when
6407 * it goes down to 0.
6409 * Removal of cgroup itself succeeds regardless of refs from swap.
6412 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
6416 mem_cgroup_remove_from_trees(memcg
);
6419 free_mem_cgroup_per_zone_info(memcg
, node
);
6421 free_percpu(memcg
->stat
);
6424 * We need to make sure that (at least for now), the jump label
6425 * destruction code runs outside of the cgroup lock. This is because
6426 * get_online_cpus(), which is called from the static_branch update,
6427 * can't be called inside the cgroup_lock. cpusets are the ones
6428 * enforcing this dependency, so if they ever change, we might as well.
6430 * schedule_work() will guarantee this happens. Be careful if you need
6431 * to move this code around, and make sure it is outside
6434 disarm_static_keys(memcg
);
6439 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6441 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6443 if (!memcg
->res
.parent
)
6445 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6447 EXPORT_SYMBOL(parent_mem_cgroup
);
6449 static void __init
mem_cgroup_soft_limit_tree_init(void)
6451 struct mem_cgroup_tree_per_node
*rtpn
;
6452 struct mem_cgroup_tree_per_zone
*rtpz
;
6453 int tmp
, node
, zone
;
6455 for_each_node(node
) {
6457 if (!node_state(node
, N_NORMAL_MEMORY
))
6459 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
6462 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6464 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6465 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
6466 rtpz
->rb_root
= RB_ROOT
;
6467 spin_lock_init(&rtpz
->lock
);
6472 static struct cgroup_subsys_state
* __ref
6473 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
6475 struct mem_cgroup
*memcg
;
6476 long error
= -ENOMEM
;
6479 memcg
= mem_cgroup_alloc();
6481 return ERR_PTR(error
);
6484 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6488 if (parent_css
== NULL
) {
6489 root_mem_cgroup
= memcg
;
6490 res_counter_init(&memcg
->res
, NULL
);
6491 res_counter_init(&memcg
->memsw
, NULL
);
6492 res_counter_init(&memcg
->kmem
, NULL
);
6495 memcg
->last_scanned_node
= MAX_NUMNODES
;
6496 INIT_LIST_HEAD(&memcg
->oom_notify
);
6497 memcg
->move_charge_at_immigrate
= 0;
6498 mutex_init(&memcg
->thresholds_lock
);
6499 spin_lock_init(&memcg
->move_lock
);
6500 vmpressure_init(&memcg
->vmpressure
);
6501 INIT_LIST_HEAD(&memcg
->event_list
);
6502 spin_lock_init(&memcg
->event_list_lock
);
6507 __mem_cgroup_free(memcg
);
6508 return ERR_PTR(error
);
6512 mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
6514 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6515 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(css
));
6517 if (css
->cgroup
->id
> MEM_CGROUP_ID_MAX
)
6523 mutex_lock(&memcg_create_mutex
);
6525 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6526 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6527 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6529 if (parent
->use_hierarchy
) {
6530 res_counter_init(&memcg
->res
, &parent
->res
);
6531 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6532 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6535 * No need to take a reference to the parent because cgroup
6536 * core guarantees its existence.
6539 res_counter_init(&memcg
->res
, NULL
);
6540 res_counter_init(&memcg
->memsw
, NULL
);
6541 res_counter_init(&memcg
->kmem
, NULL
);
6543 * Deeper hierachy with use_hierarchy == false doesn't make
6544 * much sense so let cgroup subsystem know about this
6545 * unfortunate state in our controller.
6547 if (parent
!= root_mem_cgroup
)
6548 mem_cgroup_subsys
.broken_hierarchy
= true;
6550 mutex_unlock(&memcg_create_mutex
);
6552 return memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
6556 * Announce all parents that a group from their hierarchy is gone.
6558 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup
*memcg
)
6560 struct mem_cgroup
*parent
= memcg
;
6562 while ((parent
= parent_mem_cgroup(parent
)))
6563 mem_cgroup_iter_invalidate(parent
);
6566 * if the root memcg is not hierarchical we have to check it
6569 if (!root_mem_cgroup
->use_hierarchy
)
6570 mem_cgroup_iter_invalidate(root_mem_cgroup
);
6573 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
6575 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6576 struct mem_cgroup_event
*event
, *tmp
;
6579 * Unregister events and notify userspace.
6580 * Notify userspace about cgroup removing only after rmdir of cgroup
6581 * directory to avoid race between userspace and kernelspace.
6583 spin_lock(&memcg
->event_list_lock
);
6584 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
6585 list_del_init(&event
->list
);
6586 schedule_work(&event
->remove
);
6588 spin_unlock(&memcg
->event_list_lock
);
6590 kmem_cgroup_css_offline(memcg
);
6592 mem_cgroup_invalidate_reclaim_iterators(memcg
);
6593 mem_cgroup_reparent_charges(memcg
);
6594 mem_cgroup_destroy_all_caches(memcg
);
6595 vmpressure_cleanup(&memcg
->vmpressure
);
6598 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
6600 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6602 * XXX: css_offline() would be where we should reparent all
6603 * memory to prepare the cgroup for destruction. However,
6604 * memcg does not do css_tryget() and res_counter charging
6605 * under the same RCU lock region, which means that charging
6606 * could race with offlining. Offlining only happens to
6607 * cgroups with no tasks in them but charges can show up
6608 * without any tasks from the swapin path when the target
6609 * memcg is looked up from the swapout record and not from the
6610 * current task as it usually is. A race like this can leak
6611 * charges and put pages with stale cgroup pointers into
6615 * lookup_swap_cgroup_id()
6617 * mem_cgroup_lookup()
6620 * disable css_tryget()
6623 * reparent_charges()
6624 * res_counter_charge()
6627 * pc->mem_cgroup = dead memcg
6630 * The bulk of the charges are still moved in offline_css() to
6631 * avoid pinning a lot of pages in case a long-term reference
6632 * like a swapout record is deferring the css_free() to long
6633 * after offlining. But this makes sure we catch any charges
6634 * made after offlining:
6636 mem_cgroup_reparent_charges(memcg
);
6638 memcg_destroy_kmem(memcg
);
6639 __mem_cgroup_free(memcg
);
6643 /* Handlers for move charge at task migration. */
6644 #define PRECHARGE_COUNT_AT_ONCE 256
6645 static int mem_cgroup_do_precharge(unsigned long count
)
6648 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6649 struct mem_cgroup
*memcg
= mc
.to
;
6651 if (mem_cgroup_is_root(memcg
)) {
6652 mc
.precharge
+= count
;
6653 /* we don't need css_get for root */
6656 /* try to charge at once */
6658 struct res_counter
*dummy
;
6660 * "memcg" cannot be under rmdir() because we've already checked
6661 * by cgroup_lock_live_cgroup() that it is not removed and we
6662 * are still under the same cgroup_mutex. So we can postpone
6665 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6667 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6668 PAGE_SIZE
* count
, &dummy
)) {
6669 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6672 mc
.precharge
+= count
;
6676 /* fall back to one by one charge */
6678 if (signal_pending(current
)) {
6682 if (!batch_count
--) {
6683 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6686 ret
= __mem_cgroup_try_charge(NULL
,
6687 GFP_KERNEL
, 1, &memcg
, false);
6689 /* mem_cgroup_clear_mc() will do uncharge later */
6697 * get_mctgt_type - get target type of moving charge
6698 * @vma: the vma the pte to be checked belongs
6699 * @addr: the address corresponding to the pte to be checked
6700 * @ptent: the pte to be checked
6701 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6704 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6705 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6706 * move charge. if @target is not NULL, the page is stored in target->page
6707 * with extra refcnt got(Callers should handle it).
6708 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6709 * target for charge migration. if @target is not NULL, the entry is stored
6712 * Called with pte lock held.
6719 enum mc_target_type
{
6725 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6726 unsigned long addr
, pte_t ptent
)
6728 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6730 if (!page
|| !page_mapped(page
))
6732 if (PageAnon(page
)) {
6733 /* we don't move shared anon */
6736 } else if (!move_file())
6737 /* we ignore mapcount for file pages */
6739 if (!get_page_unless_zero(page
))
6746 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6747 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6749 struct page
*page
= NULL
;
6750 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6752 if (!move_anon() || non_swap_entry(ent
))
6755 * Because lookup_swap_cache() updates some statistics counter,
6756 * we call find_get_page() with swapper_space directly.
6758 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6759 if (do_swap_account
)
6760 entry
->val
= ent
.val
;
6765 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6766 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6772 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6773 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6775 struct page
*page
= NULL
;
6776 struct address_space
*mapping
;
6779 if (!vma
->vm_file
) /* anonymous vma */
6784 mapping
= vma
->vm_file
->f_mapping
;
6785 if (pte_none(ptent
))
6786 pgoff
= linear_page_index(vma
, addr
);
6787 else /* pte_file(ptent) is true */
6788 pgoff
= pte_to_pgoff(ptent
);
6790 /* page is moved even if it's not RSS of this task(page-faulted). */
6791 page
= find_get_page(mapping
, pgoff
);
6794 /* shmem/tmpfs may report page out on swap: account for that too. */
6795 if (radix_tree_exceptional_entry(page
)) {
6796 swp_entry_t swap
= radix_to_swp_entry(page
);
6797 if (do_swap_account
)
6799 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6805 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6806 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6808 struct page
*page
= NULL
;
6809 struct page_cgroup
*pc
;
6810 enum mc_target_type ret
= MC_TARGET_NONE
;
6811 swp_entry_t ent
= { .val
= 0 };
6813 if (pte_present(ptent
))
6814 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6815 else if (is_swap_pte(ptent
))
6816 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6817 else if (pte_none(ptent
) || pte_file(ptent
))
6818 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6820 if (!page
&& !ent
.val
)
6823 pc
= lookup_page_cgroup(page
);
6825 * Do only loose check w/o page_cgroup lock.
6826 * mem_cgroup_move_account() checks the pc is valid or not under
6829 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6830 ret
= MC_TARGET_PAGE
;
6832 target
->page
= page
;
6834 if (!ret
|| !target
)
6837 /* There is a swap entry and a page doesn't exist or isn't charged */
6838 if (ent
.val
&& !ret
&&
6839 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
6840 ret
= MC_TARGET_SWAP
;
6847 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6849 * We don't consider swapping or file mapped pages because THP does not
6850 * support them for now.
6851 * Caller should make sure that pmd_trans_huge(pmd) is true.
6853 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6854 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6856 struct page
*page
= NULL
;
6857 struct page_cgroup
*pc
;
6858 enum mc_target_type ret
= MC_TARGET_NONE
;
6860 page
= pmd_page(pmd
);
6861 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
6864 pc
= lookup_page_cgroup(page
);
6865 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6866 ret
= MC_TARGET_PAGE
;
6869 target
->page
= page
;
6875 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6876 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6878 return MC_TARGET_NONE
;
6882 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6883 unsigned long addr
, unsigned long end
,
6884 struct mm_walk
*walk
)
6886 struct vm_area_struct
*vma
= walk
->private;
6890 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
6891 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6892 mc
.precharge
+= HPAGE_PMD_NR
;
6897 if (pmd_trans_unstable(pmd
))
6899 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6900 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6901 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6902 mc
.precharge
++; /* increment precharge temporarily */
6903 pte_unmap_unlock(pte
- 1, ptl
);
6909 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6911 unsigned long precharge
;
6912 struct vm_area_struct
*vma
;
6914 down_read(&mm
->mmap_sem
);
6915 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6916 struct mm_walk mem_cgroup_count_precharge_walk
= {
6917 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6921 if (is_vm_hugetlb_page(vma
))
6923 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6924 &mem_cgroup_count_precharge_walk
);
6926 up_read(&mm
->mmap_sem
);
6928 precharge
= mc
.precharge
;
6934 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6936 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6938 VM_BUG_ON(mc
.moving_task
);
6939 mc
.moving_task
= current
;
6940 return mem_cgroup_do_precharge(precharge
);
6943 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6944 static void __mem_cgroup_clear_mc(void)
6946 struct mem_cgroup
*from
= mc
.from
;
6947 struct mem_cgroup
*to
= mc
.to
;
6950 /* we must uncharge all the leftover precharges from mc.to */
6952 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6956 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6957 * we must uncharge here.
6959 if (mc
.moved_charge
) {
6960 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6961 mc
.moved_charge
= 0;
6963 /* we must fixup refcnts and charges */
6964 if (mc
.moved_swap
) {
6965 /* uncharge swap account from the old cgroup */
6966 if (!mem_cgroup_is_root(mc
.from
))
6967 res_counter_uncharge(&mc
.from
->memsw
,
6968 PAGE_SIZE
* mc
.moved_swap
);
6970 for (i
= 0; i
< mc
.moved_swap
; i
++)
6971 css_put(&mc
.from
->css
);
6973 if (!mem_cgroup_is_root(mc
.to
)) {
6975 * we charged both to->res and to->memsw, so we should
6978 res_counter_uncharge(&mc
.to
->res
,
6979 PAGE_SIZE
* mc
.moved_swap
);
6981 /* we've already done css_get(mc.to) */
6984 memcg_oom_recover(from
);
6985 memcg_oom_recover(to
);
6986 wake_up_all(&mc
.waitq
);
6989 static void mem_cgroup_clear_mc(void)
6991 struct mem_cgroup
*from
= mc
.from
;
6994 * we must clear moving_task before waking up waiters at the end of
6997 mc
.moving_task
= NULL
;
6998 __mem_cgroup_clear_mc();
6999 spin_lock(&mc
.lock
);
7002 spin_unlock(&mc
.lock
);
7003 mem_cgroup_end_move(from
);
7006 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7007 struct cgroup_taskset
*tset
)
7009 struct task_struct
*p
= cgroup_taskset_first(tset
);
7011 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7012 unsigned long move_charge_at_immigrate
;
7015 * We are now commited to this value whatever it is. Changes in this
7016 * tunable will only affect upcoming migrations, not the current one.
7017 * So we need to save it, and keep it going.
7019 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
7020 if (move_charge_at_immigrate
) {
7021 struct mm_struct
*mm
;
7022 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
7024 VM_BUG_ON(from
== memcg
);
7026 mm
= get_task_mm(p
);
7029 /* We move charges only when we move a owner of the mm */
7030 if (mm
->owner
== p
) {
7033 VM_BUG_ON(mc
.precharge
);
7034 VM_BUG_ON(mc
.moved_charge
);
7035 VM_BUG_ON(mc
.moved_swap
);
7036 mem_cgroup_start_move(from
);
7037 spin_lock(&mc
.lock
);
7040 mc
.immigrate_flags
= move_charge_at_immigrate
;
7041 spin_unlock(&mc
.lock
);
7042 /* We set mc.moving_task later */
7044 ret
= mem_cgroup_precharge_mc(mm
);
7046 mem_cgroup_clear_mc();
7053 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7054 struct cgroup_taskset
*tset
)
7056 mem_cgroup_clear_mc();
7059 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
7060 unsigned long addr
, unsigned long end
,
7061 struct mm_walk
*walk
)
7064 struct vm_area_struct
*vma
= walk
->private;
7067 enum mc_target_type target_type
;
7068 union mc_target target
;
7070 struct page_cgroup
*pc
;
7073 * We don't take compound_lock() here but no race with splitting thp
7075 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
7076 * under splitting, which means there's no concurrent thp split,
7077 * - if another thread runs into split_huge_page() just after we
7078 * entered this if-block, the thread must wait for page table lock
7079 * to be unlocked in __split_huge_page_splitting(), where the main
7080 * part of thp split is not executed yet.
7082 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
7083 if (mc
.precharge
< HPAGE_PMD_NR
) {
7087 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
7088 if (target_type
== MC_TARGET_PAGE
) {
7090 if (!isolate_lru_page(page
)) {
7091 pc
= lookup_page_cgroup(page
);
7092 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
7093 pc
, mc
.from
, mc
.to
)) {
7094 mc
.precharge
-= HPAGE_PMD_NR
;
7095 mc
.moved_charge
+= HPAGE_PMD_NR
;
7097 putback_lru_page(page
);
7105 if (pmd_trans_unstable(pmd
))
7108 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
7109 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
7110 pte_t ptent
= *(pte
++);
7116 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
7117 case MC_TARGET_PAGE
:
7119 if (isolate_lru_page(page
))
7121 pc
= lookup_page_cgroup(page
);
7122 if (!mem_cgroup_move_account(page
, 1, pc
,
7125 /* we uncharge from mc.from later. */
7128 putback_lru_page(page
);
7129 put
: /* get_mctgt_type() gets the page */
7132 case MC_TARGET_SWAP
:
7134 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
7136 /* we fixup refcnts and charges later. */
7144 pte_unmap_unlock(pte
- 1, ptl
);
7149 * We have consumed all precharges we got in can_attach().
7150 * We try charge one by one, but don't do any additional
7151 * charges to mc.to if we have failed in charge once in attach()
7154 ret
= mem_cgroup_do_precharge(1);
7162 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
7164 struct vm_area_struct
*vma
;
7166 lru_add_drain_all();
7168 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
7170 * Someone who are holding the mmap_sem might be waiting in
7171 * waitq. So we cancel all extra charges, wake up all waiters,
7172 * and retry. Because we cancel precharges, we might not be able
7173 * to move enough charges, but moving charge is a best-effort
7174 * feature anyway, so it wouldn't be a big problem.
7176 __mem_cgroup_clear_mc();
7180 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
7182 struct mm_walk mem_cgroup_move_charge_walk
= {
7183 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
7187 if (is_vm_hugetlb_page(vma
))
7189 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
7190 &mem_cgroup_move_charge_walk
);
7193 * means we have consumed all precharges and failed in
7194 * doing additional charge. Just abandon here.
7198 up_read(&mm
->mmap_sem
);
7201 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7202 struct cgroup_taskset
*tset
)
7204 struct task_struct
*p
= cgroup_taskset_first(tset
);
7205 struct mm_struct
*mm
= get_task_mm(p
);
7209 mem_cgroup_move_charge(mm
);
7213 mem_cgroup_clear_mc();
7215 #else /* !CONFIG_MMU */
7216 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7217 struct cgroup_taskset
*tset
)
7221 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7222 struct cgroup_taskset
*tset
)
7225 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7226 struct cgroup_taskset
*tset
)
7232 * Cgroup retains root cgroups across [un]mount cycles making it necessary
7233 * to verify sane_behavior flag on each mount attempt.
7235 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
7238 * use_hierarchy is forced with sane_behavior. cgroup core
7239 * guarantees that @root doesn't have any children, so turning it
7240 * on for the root memcg is enough.
7242 if (cgroup_sane_behavior(root_css
->cgroup
))
7243 mem_cgroup_from_css(root_css
)->use_hierarchy
= true;
7246 struct cgroup_subsys mem_cgroup_subsys
= {
7248 .subsys_id
= mem_cgroup_subsys_id
,
7249 .css_alloc
= mem_cgroup_css_alloc
,
7250 .css_online
= mem_cgroup_css_online
,
7251 .css_offline
= mem_cgroup_css_offline
,
7252 .css_free
= mem_cgroup_css_free
,
7253 .can_attach
= mem_cgroup_can_attach
,
7254 .cancel_attach
= mem_cgroup_cancel_attach
,
7255 .attach
= mem_cgroup_move_task
,
7256 .bind
= mem_cgroup_bind
,
7257 .base_cftypes
= mem_cgroup_files
,
7261 #ifdef CONFIG_MEMCG_SWAP
7262 static int __init
enable_swap_account(char *s
)
7264 if (!strcmp(s
, "1"))
7265 really_do_swap_account
= 1;
7266 else if (!strcmp(s
, "0"))
7267 really_do_swap_account
= 0;
7270 __setup("swapaccount=", enable_swap_account
);
7272 static void __init
memsw_file_init(void)
7274 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys
, memsw_cgroup_files
));
7277 static void __init
enable_swap_cgroup(void)
7279 if (!mem_cgroup_disabled() && really_do_swap_account
) {
7280 do_swap_account
= 1;
7286 static void __init
enable_swap_cgroup(void)
7292 * subsys_initcall() for memory controller.
7294 * Some parts like hotcpu_notifier() have to be initialized from this context
7295 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
7296 * everything that doesn't depend on a specific mem_cgroup structure should
7297 * be initialized from here.
7299 static int __init
mem_cgroup_init(void)
7301 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
7302 enable_swap_cgroup();
7303 mem_cgroup_soft_limit_tree_init();
7307 subsys_initcall(mem_cgroup_init
);