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 memory_cgrp_subsys __read_mostly
;
70 EXPORT_SYMBOL(memory_cgrp_subsys
);
72 #define MEM_CGROUP_RECLAIM_RETRIES 5
73 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
75 #ifdef CONFIG_MEMCG_SWAP
76 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
77 int do_swap_account __read_mostly
;
79 /* for remember boot option*/
80 #ifdef CONFIG_MEMCG_SWAP_ENABLED
81 static int really_do_swap_account __initdata
= 1;
83 static int really_do_swap_account __initdata
= 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, &memory_cgrp_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
)
925 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
926 * counted as CACHE even if it's on ANON LRU.
929 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
932 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
935 if (PageTransHuge(page
))
936 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
939 /* pagein of a big page is an event. So, ignore page size */
941 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
943 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
944 nr_pages
= -nr_pages
; /* for event */
947 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
951 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
953 struct mem_cgroup_per_zone
*mz
;
955 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
956 return mz
->lru_size
[lru
];
960 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
961 unsigned int lru_mask
)
963 struct mem_cgroup_per_zone
*mz
;
965 unsigned long ret
= 0;
967 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
970 if (BIT(lru
) & lru_mask
)
971 ret
+= mz
->lru_size
[lru
];
977 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
978 int nid
, unsigned int lru_mask
)
983 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
984 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
990 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
991 unsigned int lru_mask
)
996 for_each_node_state(nid
, N_MEMORY
)
997 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
1001 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
1002 enum mem_cgroup_events_target target
)
1004 unsigned long val
, next
;
1006 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
1007 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
1008 /* from time_after() in jiffies.h */
1009 if ((long)next
- (long)val
< 0) {
1011 case MEM_CGROUP_TARGET_THRESH
:
1012 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
1014 case MEM_CGROUP_TARGET_SOFTLIMIT
:
1015 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
1017 case MEM_CGROUP_TARGET_NUMAINFO
:
1018 next
= val
+ NUMAINFO_EVENTS_TARGET
;
1023 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
1030 * Check events in order.
1033 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
1036 /* threshold event is triggered in finer grain than soft limit */
1037 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1038 MEM_CGROUP_TARGET_THRESH
))) {
1040 bool do_numainfo __maybe_unused
;
1042 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1043 MEM_CGROUP_TARGET_SOFTLIMIT
);
1044 #if MAX_NUMNODES > 1
1045 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1046 MEM_CGROUP_TARGET_NUMAINFO
);
1050 mem_cgroup_threshold(memcg
);
1051 if (unlikely(do_softlimit
))
1052 mem_cgroup_update_tree(memcg
, page
);
1053 #if MAX_NUMNODES > 1
1054 if (unlikely(do_numainfo
))
1055 atomic_inc(&memcg
->numainfo_events
);
1061 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1064 * mm_update_next_owner() may clear mm->owner to NULL
1065 * if it races with swapoff, page migration, etc.
1066 * So this can be called with p == NULL.
1071 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
1074 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1076 struct mem_cgroup
*memcg
= NULL
;
1081 * Because we have no locks, mm->owner's may be being moved to other
1082 * cgroup. We use css_tryget() here even if this looks
1083 * pessimistic (rather than adding locks here).
1087 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1088 if (unlikely(!memcg
))
1090 } while (!css_tryget(&memcg
->css
));
1096 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1097 * ref. count) or NULL if the whole root's subtree has been visited.
1099 * helper function to be used by mem_cgroup_iter
1101 static struct mem_cgroup
*__mem_cgroup_iter_next(struct mem_cgroup
*root
,
1102 struct mem_cgroup
*last_visited
)
1104 struct cgroup_subsys_state
*prev_css
, *next_css
;
1106 prev_css
= last_visited
? &last_visited
->css
: NULL
;
1108 next_css
= css_next_descendant_pre(prev_css
, &root
->css
);
1111 * Even if we found a group we have to make sure it is
1112 * alive. css && !memcg means that the groups should be
1113 * skipped and we should continue the tree walk.
1114 * last_visited css is safe to use because it is
1115 * protected by css_get and the tree walk is rcu safe.
1117 * We do not take a reference on the root of the tree walk
1118 * because we might race with the root removal when it would
1119 * be the only node in the iterated hierarchy and mem_cgroup_iter
1120 * would end up in an endless loop because it expects that at
1121 * least one valid node will be returned. Root cannot disappear
1122 * because caller of the iterator should hold it already so
1123 * skipping css reference should be safe.
1126 if ((next_css
== &root
->css
) ||
1127 ((next_css
->flags
& CSS_ONLINE
) && css_tryget(next_css
)))
1128 return mem_cgroup_from_css(next_css
);
1130 prev_css
= next_css
;
1137 static void mem_cgroup_iter_invalidate(struct mem_cgroup
*root
)
1140 * When a group in the hierarchy below root is destroyed, the
1141 * hierarchy iterator can no longer be trusted since it might
1142 * have pointed to the destroyed group. Invalidate it.
1144 atomic_inc(&root
->dead_count
);
1147 static struct mem_cgroup
*
1148 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter
*iter
,
1149 struct mem_cgroup
*root
,
1152 struct mem_cgroup
*position
= NULL
;
1154 * A cgroup destruction happens in two stages: offlining and
1155 * release. They are separated by a RCU grace period.
1157 * If the iterator is valid, we may still race with an
1158 * offlining. The RCU lock ensures the object won't be
1159 * released, tryget will fail if we lost the race.
1161 *sequence
= atomic_read(&root
->dead_count
);
1162 if (iter
->last_dead_count
== *sequence
) {
1164 position
= iter
->last_visited
;
1167 * We cannot take a reference to root because we might race
1168 * with root removal and returning NULL would end up in
1169 * an endless loop on the iterator user level when root
1170 * would be returned all the time.
1172 if (position
&& position
!= root
&&
1173 !css_tryget(&position
->css
))
1179 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter
*iter
,
1180 struct mem_cgroup
*last_visited
,
1181 struct mem_cgroup
*new_position
,
1182 struct mem_cgroup
*root
,
1185 /* root reference counting symmetric to mem_cgroup_iter_load */
1186 if (last_visited
&& last_visited
!= root
)
1187 css_put(&last_visited
->css
);
1189 * We store the sequence count from the time @last_visited was
1190 * loaded successfully instead of rereading it here so that we
1191 * don't lose destruction events in between. We could have
1192 * raced with the destruction of @new_position after all.
1194 iter
->last_visited
= new_position
;
1196 iter
->last_dead_count
= sequence
;
1200 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1201 * @root: hierarchy root
1202 * @prev: previously returned memcg, NULL on first invocation
1203 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1205 * Returns references to children of the hierarchy below @root, or
1206 * @root itself, or %NULL after a full round-trip.
1208 * Caller must pass the return value in @prev on subsequent
1209 * invocations for reference counting, or use mem_cgroup_iter_break()
1210 * to cancel a hierarchy walk before the round-trip is complete.
1212 * Reclaimers can specify a zone and a priority level in @reclaim to
1213 * divide up the memcgs in the hierarchy among all concurrent
1214 * reclaimers operating on the same zone and priority.
1216 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1217 struct mem_cgroup
*prev
,
1218 struct mem_cgroup_reclaim_cookie
*reclaim
)
1220 struct mem_cgroup
*memcg
= NULL
;
1221 struct mem_cgroup
*last_visited
= NULL
;
1223 if (mem_cgroup_disabled())
1227 root
= root_mem_cgroup
;
1229 if (prev
&& !reclaim
)
1230 last_visited
= prev
;
1232 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1240 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1241 int uninitialized_var(seq
);
1244 int nid
= zone_to_nid(reclaim
->zone
);
1245 int zid
= zone_idx(reclaim
->zone
);
1246 struct mem_cgroup_per_zone
*mz
;
1248 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1249 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1250 if (prev
&& reclaim
->generation
!= iter
->generation
) {
1251 iter
->last_visited
= NULL
;
1255 last_visited
= mem_cgroup_iter_load(iter
, root
, &seq
);
1258 memcg
= __mem_cgroup_iter_next(root
, last_visited
);
1261 mem_cgroup_iter_update(iter
, last_visited
, memcg
, root
,
1266 else if (!prev
&& memcg
)
1267 reclaim
->generation
= iter
->generation
;
1276 if (prev
&& prev
!= root
)
1277 css_put(&prev
->css
);
1283 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1284 * @root: hierarchy root
1285 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1287 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1288 struct mem_cgroup
*prev
)
1291 root
= root_mem_cgroup
;
1292 if (prev
&& prev
!= root
)
1293 css_put(&prev
->css
);
1297 * Iteration constructs for visiting all cgroups (under a tree). If
1298 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1299 * be used for reference counting.
1301 #define for_each_mem_cgroup_tree(iter, root) \
1302 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1304 iter = mem_cgroup_iter(root, iter, NULL))
1306 #define for_each_mem_cgroup(iter) \
1307 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1309 iter = mem_cgroup_iter(NULL, iter, NULL))
1311 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1313 struct mem_cgroup
*memcg
;
1316 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1317 if (unlikely(!memcg
))
1322 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1325 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1333 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1336 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1337 * @zone: zone of the wanted lruvec
1338 * @memcg: memcg of the wanted lruvec
1340 * Returns the lru list vector holding pages for the given @zone and
1341 * @mem. This can be the global zone lruvec, if the memory controller
1344 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1345 struct mem_cgroup
*memcg
)
1347 struct mem_cgroup_per_zone
*mz
;
1348 struct lruvec
*lruvec
;
1350 if (mem_cgroup_disabled()) {
1351 lruvec
= &zone
->lruvec
;
1355 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1356 lruvec
= &mz
->lruvec
;
1359 * Since a node can be onlined after the mem_cgroup was created,
1360 * we have to be prepared to initialize lruvec->zone here;
1361 * and if offlined then reonlined, we need to reinitialize it.
1363 if (unlikely(lruvec
->zone
!= zone
))
1364 lruvec
->zone
= zone
;
1369 * Following LRU functions are allowed to be used without PCG_LOCK.
1370 * Operations are called by routine of global LRU independently from memcg.
1371 * What we have to take care of here is validness of pc->mem_cgroup.
1373 * Changes to pc->mem_cgroup happens when
1376 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1377 * It is added to LRU before charge.
1378 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1379 * When moving account, the page is not on LRU. It's isolated.
1383 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1385 * @zone: zone of the page
1387 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1389 struct mem_cgroup_per_zone
*mz
;
1390 struct mem_cgroup
*memcg
;
1391 struct page_cgroup
*pc
;
1392 struct lruvec
*lruvec
;
1394 if (mem_cgroup_disabled()) {
1395 lruvec
= &zone
->lruvec
;
1399 pc
= lookup_page_cgroup(page
);
1400 memcg
= pc
->mem_cgroup
;
1403 * Surreptitiously switch any uncharged offlist page to root:
1404 * an uncharged page off lru does nothing to secure
1405 * its former mem_cgroup from sudden removal.
1407 * Our caller holds lru_lock, and PageCgroupUsed is updated
1408 * under page_cgroup lock: between them, they make all uses
1409 * of pc->mem_cgroup safe.
1411 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1412 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1414 mz
= page_cgroup_zoneinfo(memcg
, page
);
1415 lruvec
= &mz
->lruvec
;
1418 * Since a node can be onlined after the mem_cgroup was created,
1419 * we have to be prepared to initialize lruvec->zone here;
1420 * and if offlined then reonlined, we need to reinitialize it.
1422 if (unlikely(lruvec
->zone
!= zone
))
1423 lruvec
->zone
= zone
;
1428 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1429 * @lruvec: mem_cgroup per zone lru vector
1430 * @lru: index of lru list the page is sitting on
1431 * @nr_pages: positive when adding or negative when removing
1433 * This function must be called when a page is added to or removed from an
1436 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1439 struct mem_cgroup_per_zone
*mz
;
1440 unsigned long *lru_size
;
1442 if (mem_cgroup_disabled())
1445 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1446 lru_size
= mz
->lru_size
+ lru
;
1447 *lru_size
+= nr_pages
;
1448 VM_BUG_ON((long)(*lru_size
) < 0);
1452 * Checks whether given mem is same or in the root_mem_cgroup's
1455 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1456 struct mem_cgroup
*memcg
)
1458 if (root_memcg
== memcg
)
1460 if (!root_memcg
->use_hierarchy
|| !memcg
)
1462 return cgroup_is_descendant(memcg
->css
.cgroup
, root_memcg
->css
.cgroup
);
1465 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1466 struct mem_cgroup
*memcg
)
1471 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1476 bool task_in_mem_cgroup(struct task_struct
*task
,
1477 const struct mem_cgroup
*memcg
)
1479 struct mem_cgroup
*curr
= NULL
;
1480 struct task_struct
*p
;
1483 p
= find_lock_task_mm(task
);
1485 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1489 * All threads may have already detached their mm's, but the oom
1490 * killer still needs to detect if they have already been oom
1491 * killed to prevent needlessly killing additional tasks.
1494 curr
= mem_cgroup_from_task(task
);
1496 css_get(&curr
->css
);
1502 * We should check use_hierarchy of "memcg" not "curr". Because checking
1503 * use_hierarchy of "curr" here make this function true if hierarchy is
1504 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1505 * hierarchy(even if use_hierarchy is disabled in "memcg").
1507 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1508 css_put(&curr
->css
);
1512 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1514 unsigned long inactive_ratio
;
1515 unsigned long inactive
;
1516 unsigned long active
;
1519 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1520 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1522 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1524 inactive_ratio
= int_sqrt(10 * gb
);
1528 return inactive
* inactive_ratio
< active
;
1531 #define mem_cgroup_from_res_counter(counter, member) \
1532 container_of(counter, struct mem_cgroup, member)
1535 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1536 * @memcg: the memory cgroup
1538 * Returns the maximum amount of memory @mem can be charged with, in
1541 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1543 unsigned long long margin
;
1545 margin
= res_counter_margin(&memcg
->res
);
1546 if (do_swap_account
)
1547 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1548 return margin
>> PAGE_SHIFT
;
1551 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1554 if (!css_parent(&memcg
->css
))
1555 return vm_swappiness
;
1557 return memcg
->swappiness
;
1561 * memcg->moving_account is used for checking possibility that some thread is
1562 * calling move_account(). When a thread on CPU-A starts moving pages under
1563 * a memcg, other threads should check memcg->moving_account under
1564 * rcu_read_lock(), like this:
1568 * memcg->moving_account+1 if (memcg->mocing_account)
1570 * synchronize_rcu() update something.
1575 /* for quick checking without looking up memcg */
1576 atomic_t memcg_moving __read_mostly
;
1578 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1580 atomic_inc(&memcg_moving
);
1581 atomic_inc(&memcg
->moving_account
);
1585 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1588 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1589 * We check NULL in callee rather than caller.
1592 atomic_dec(&memcg_moving
);
1593 atomic_dec(&memcg
->moving_account
);
1598 * 2 routines for checking "mem" is under move_account() or not.
1600 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1601 * is used for avoiding races in accounting. If true,
1602 * pc->mem_cgroup may be overwritten.
1604 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1605 * under hierarchy of moving cgroups. This is for
1606 * waiting at hith-memory prressure caused by "move".
1609 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1611 VM_BUG_ON(!rcu_read_lock_held());
1612 return atomic_read(&memcg
->moving_account
) > 0;
1615 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1617 struct mem_cgroup
*from
;
1618 struct mem_cgroup
*to
;
1621 * Unlike task_move routines, we access mc.to, mc.from not under
1622 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1624 spin_lock(&mc
.lock
);
1630 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1631 || mem_cgroup_same_or_subtree(memcg
, to
);
1633 spin_unlock(&mc
.lock
);
1637 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1639 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1640 if (mem_cgroup_under_move(memcg
)) {
1642 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1643 /* moving charge context might have finished. */
1646 finish_wait(&mc
.waitq
, &wait
);
1654 * Take this lock when
1655 * - a code tries to modify page's memcg while it's USED.
1656 * - a code tries to modify page state accounting in a memcg.
1657 * see mem_cgroup_stolen(), too.
1659 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1660 unsigned long *flags
)
1662 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1665 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1666 unsigned long *flags
)
1668 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1671 #define K(x) ((x) << (PAGE_SHIFT-10))
1673 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1674 * @memcg: The memory cgroup that went over limit
1675 * @p: Task that is going to be killed
1677 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1680 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1682 /* oom_info_lock ensures that parallel ooms do not interleave */
1683 static DEFINE_MUTEX(oom_info_lock
);
1684 struct mem_cgroup
*iter
;
1690 mutex_lock(&oom_info_lock
);
1693 pr_info("Task in ");
1694 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1695 pr_info(" killed as a result of limit of ");
1696 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1701 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1702 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1703 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1704 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1705 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1706 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1707 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1708 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1709 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1710 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1711 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1712 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1714 for_each_mem_cgroup_tree(iter
, memcg
) {
1715 pr_info("Memory cgroup stats for ");
1716 pr_cont_cgroup_path(iter
->css
.cgroup
);
1719 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1720 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1722 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1723 K(mem_cgroup_read_stat(iter
, i
)));
1726 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1727 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1728 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1732 mutex_unlock(&oom_info_lock
);
1736 * This function returns the number of memcg under hierarchy tree. Returns
1737 * 1(self count) if no children.
1739 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1742 struct mem_cgroup
*iter
;
1744 for_each_mem_cgroup_tree(iter
, memcg
)
1750 * Return the memory (and swap, if configured) limit for a memcg.
1752 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1756 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1759 * Do not consider swap space if we cannot swap due to swappiness
1761 if (mem_cgroup_swappiness(memcg
)) {
1764 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1765 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1768 * If memsw is finite and limits the amount of swap space
1769 * available to this memcg, return that limit.
1771 limit
= min(limit
, memsw
);
1777 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1780 struct mem_cgroup
*iter
;
1781 unsigned long chosen_points
= 0;
1782 unsigned long totalpages
;
1783 unsigned int points
= 0;
1784 struct task_struct
*chosen
= NULL
;
1787 * If current has a pending SIGKILL or is exiting, then automatically
1788 * select it. The goal is to allow it to allocate so that it may
1789 * quickly exit and free its memory.
1791 if (fatal_signal_pending(current
) || current
->flags
& PF_EXITING
) {
1792 set_thread_flag(TIF_MEMDIE
);
1796 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1797 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1798 for_each_mem_cgroup_tree(iter
, memcg
) {
1799 struct css_task_iter it
;
1800 struct task_struct
*task
;
1802 css_task_iter_start(&iter
->css
, &it
);
1803 while ((task
= css_task_iter_next(&it
))) {
1804 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1806 case OOM_SCAN_SELECT
:
1808 put_task_struct(chosen
);
1810 chosen_points
= ULONG_MAX
;
1811 get_task_struct(chosen
);
1813 case OOM_SCAN_CONTINUE
:
1815 case OOM_SCAN_ABORT
:
1816 css_task_iter_end(&it
);
1817 mem_cgroup_iter_break(memcg
, iter
);
1819 put_task_struct(chosen
);
1824 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1825 if (!points
|| points
< chosen_points
)
1827 /* Prefer thread group leaders for display purposes */
1828 if (points
== chosen_points
&&
1829 thread_group_leader(chosen
))
1833 put_task_struct(chosen
);
1835 chosen_points
= points
;
1836 get_task_struct(chosen
);
1838 css_task_iter_end(&it
);
1843 points
= chosen_points
* 1000 / totalpages
;
1844 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1845 NULL
, "Memory cgroup out of memory");
1848 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1850 unsigned long flags
)
1852 unsigned long total
= 0;
1853 bool noswap
= false;
1856 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1858 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1861 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1863 drain_all_stock_async(memcg
);
1864 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1866 * Allow limit shrinkers, which are triggered directly
1867 * by userspace, to catch signals and stop reclaim
1868 * after minimal progress, regardless of the margin.
1870 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1872 if (mem_cgroup_margin(memcg
))
1875 * If nothing was reclaimed after two attempts, there
1876 * may be no reclaimable pages in this hierarchy.
1885 * test_mem_cgroup_node_reclaimable
1886 * @memcg: the target memcg
1887 * @nid: the node ID to be checked.
1888 * @noswap : specify true here if the user wants flle only information.
1890 * This function returns whether the specified memcg contains any
1891 * reclaimable pages on a node. Returns true if there are any reclaimable
1892 * pages in the node.
1894 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1895 int nid
, bool noswap
)
1897 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1899 if (noswap
|| !total_swap_pages
)
1901 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1906 #if MAX_NUMNODES > 1
1909 * Always updating the nodemask is not very good - even if we have an empty
1910 * list or the wrong list here, we can start from some node and traverse all
1911 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1914 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1918 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1919 * pagein/pageout changes since the last update.
1921 if (!atomic_read(&memcg
->numainfo_events
))
1923 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1926 /* make a nodemask where this memcg uses memory from */
1927 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1929 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1931 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1932 node_clear(nid
, memcg
->scan_nodes
);
1935 atomic_set(&memcg
->numainfo_events
, 0);
1936 atomic_set(&memcg
->numainfo_updating
, 0);
1940 * Selecting a node where we start reclaim from. Because what we need is just
1941 * reducing usage counter, start from anywhere is O,K. Considering
1942 * memory reclaim from current node, there are pros. and cons.
1944 * Freeing memory from current node means freeing memory from a node which
1945 * we'll use or we've used. So, it may make LRU bad. And if several threads
1946 * hit limits, it will see a contention on a node. But freeing from remote
1947 * node means more costs for memory reclaim because of memory latency.
1949 * Now, we use round-robin. Better algorithm is welcomed.
1951 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1955 mem_cgroup_may_update_nodemask(memcg
);
1956 node
= memcg
->last_scanned_node
;
1958 node
= next_node(node
, memcg
->scan_nodes
);
1959 if (node
== MAX_NUMNODES
)
1960 node
= first_node(memcg
->scan_nodes
);
1962 * We call this when we hit limit, not when pages are added to LRU.
1963 * No LRU may hold pages because all pages are UNEVICTABLE or
1964 * memcg is too small and all pages are not on LRU. In that case,
1965 * we use curret node.
1967 if (unlikely(node
== MAX_NUMNODES
))
1968 node
= numa_node_id();
1970 memcg
->last_scanned_node
= node
;
1975 * Check all nodes whether it contains reclaimable pages or not.
1976 * For quick scan, we make use of scan_nodes. This will allow us to skip
1977 * unused nodes. But scan_nodes is lazily updated and may not cotain
1978 * enough new information. We need to do double check.
1980 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1985 * quick check...making use of scan_node.
1986 * We can skip unused nodes.
1988 if (!nodes_empty(memcg
->scan_nodes
)) {
1989 for (nid
= first_node(memcg
->scan_nodes
);
1991 nid
= next_node(nid
, memcg
->scan_nodes
)) {
1993 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1998 * Check rest of nodes.
2000 for_each_node_state(nid
, N_MEMORY
) {
2001 if (node_isset(nid
, memcg
->scan_nodes
))
2003 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
2010 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
2015 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
2017 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
2021 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
2024 unsigned long *total_scanned
)
2026 struct mem_cgroup
*victim
= NULL
;
2029 unsigned long excess
;
2030 unsigned long nr_scanned
;
2031 struct mem_cgroup_reclaim_cookie reclaim
= {
2036 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
2039 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
2044 * If we have not been able to reclaim
2045 * anything, it might because there are
2046 * no reclaimable pages under this hierarchy
2051 * We want to do more targeted reclaim.
2052 * excess >> 2 is not to excessive so as to
2053 * reclaim too much, nor too less that we keep
2054 * coming back to reclaim from this cgroup
2056 if (total
>= (excess
>> 2) ||
2057 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
2062 if (!mem_cgroup_reclaimable(victim
, false))
2064 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
2066 *total_scanned
+= nr_scanned
;
2067 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
2070 mem_cgroup_iter_break(root_memcg
, victim
);
2074 #ifdef CONFIG_LOCKDEP
2075 static struct lockdep_map memcg_oom_lock_dep_map
= {
2076 .name
= "memcg_oom_lock",
2080 static DEFINE_SPINLOCK(memcg_oom_lock
);
2083 * Check OOM-Killer is already running under our hierarchy.
2084 * If someone is running, return false.
2086 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
2088 struct mem_cgroup
*iter
, *failed
= NULL
;
2090 spin_lock(&memcg_oom_lock
);
2092 for_each_mem_cgroup_tree(iter
, memcg
) {
2093 if (iter
->oom_lock
) {
2095 * this subtree of our hierarchy is already locked
2096 * so we cannot give a lock.
2099 mem_cgroup_iter_break(memcg
, iter
);
2102 iter
->oom_lock
= true;
2107 * OK, we failed to lock the whole subtree so we have
2108 * to clean up what we set up to the failing subtree
2110 for_each_mem_cgroup_tree(iter
, memcg
) {
2111 if (iter
== failed
) {
2112 mem_cgroup_iter_break(memcg
, iter
);
2115 iter
->oom_lock
= false;
2118 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
2120 spin_unlock(&memcg_oom_lock
);
2125 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2127 struct mem_cgroup
*iter
;
2129 spin_lock(&memcg_oom_lock
);
2130 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
2131 for_each_mem_cgroup_tree(iter
, memcg
)
2132 iter
->oom_lock
= false;
2133 spin_unlock(&memcg_oom_lock
);
2136 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2138 struct mem_cgroup
*iter
;
2140 for_each_mem_cgroup_tree(iter
, memcg
)
2141 atomic_inc(&iter
->under_oom
);
2144 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2146 struct mem_cgroup
*iter
;
2149 * When a new child is created while the hierarchy is under oom,
2150 * mem_cgroup_oom_lock() may not be called. We have to use
2151 * atomic_add_unless() here.
2153 for_each_mem_cgroup_tree(iter
, memcg
)
2154 atomic_add_unless(&iter
->under_oom
, -1, 0);
2157 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2159 struct oom_wait_info
{
2160 struct mem_cgroup
*memcg
;
2164 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2165 unsigned mode
, int sync
, void *arg
)
2167 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2168 struct mem_cgroup
*oom_wait_memcg
;
2169 struct oom_wait_info
*oom_wait_info
;
2171 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2172 oom_wait_memcg
= oom_wait_info
->memcg
;
2175 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2176 * Then we can use css_is_ancestor without taking care of RCU.
2178 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2179 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2181 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2184 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2186 atomic_inc(&memcg
->oom_wakeups
);
2187 /* for filtering, pass "memcg" as argument. */
2188 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2191 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2193 if (memcg
&& atomic_read(&memcg
->under_oom
))
2194 memcg_wakeup_oom(memcg
);
2197 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
2199 if (!current
->memcg_oom
.may_oom
)
2202 * We are in the middle of the charge context here, so we
2203 * don't want to block when potentially sitting on a callstack
2204 * that holds all kinds of filesystem and mm locks.
2206 * Also, the caller may handle a failed allocation gracefully
2207 * (like optional page cache readahead) and so an OOM killer
2208 * invocation might not even be necessary.
2210 * That's why we don't do anything here except remember the
2211 * OOM context and then deal with it at the end of the page
2212 * fault when the stack is unwound, the locks are released,
2213 * and when we know whether the fault was overall successful.
2215 css_get(&memcg
->css
);
2216 current
->memcg_oom
.memcg
= memcg
;
2217 current
->memcg_oom
.gfp_mask
= mask
;
2218 current
->memcg_oom
.order
= order
;
2222 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2223 * @handle: actually kill/wait or just clean up the OOM state
2225 * This has to be called at the end of a page fault if the memcg OOM
2226 * handler was enabled.
2228 * Memcg supports userspace OOM handling where failed allocations must
2229 * sleep on a waitqueue until the userspace task resolves the
2230 * situation. Sleeping directly in the charge context with all kinds
2231 * of locks held is not a good idea, instead we remember an OOM state
2232 * in the task and mem_cgroup_oom_synchronize() has to be called at
2233 * the end of the page fault to complete the OOM handling.
2235 * Returns %true if an ongoing memcg OOM situation was detected and
2236 * completed, %false otherwise.
2238 bool mem_cgroup_oom_synchronize(bool handle
)
2240 struct mem_cgroup
*memcg
= current
->memcg_oom
.memcg
;
2241 struct oom_wait_info owait
;
2244 /* OOM is global, do not handle */
2251 owait
.memcg
= memcg
;
2252 owait
.wait
.flags
= 0;
2253 owait
.wait
.func
= memcg_oom_wake_function
;
2254 owait
.wait
.private = current
;
2255 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2257 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2258 mem_cgroup_mark_under_oom(memcg
);
2260 locked
= mem_cgroup_oom_trylock(memcg
);
2263 mem_cgroup_oom_notify(memcg
);
2265 if (locked
&& !memcg
->oom_kill_disable
) {
2266 mem_cgroup_unmark_under_oom(memcg
);
2267 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2268 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom
.gfp_mask
,
2269 current
->memcg_oom
.order
);
2272 mem_cgroup_unmark_under_oom(memcg
);
2273 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2277 mem_cgroup_oom_unlock(memcg
);
2279 * There is no guarantee that an OOM-lock contender
2280 * sees the wakeups triggered by the OOM kill
2281 * uncharges. Wake any sleepers explicitely.
2283 memcg_oom_recover(memcg
);
2286 current
->memcg_oom
.memcg
= NULL
;
2287 css_put(&memcg
->css
);
2292 * Currently used to update mapped file statistics, but the routine can be
2293 * generalized to update other statistics as well.
2295 * Notes: Race condition
2297 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2298 * it tends to be costly. But considering some conditions, we doesn't need
2299 * to do so _always_.
2301 * Considering "charge", lock_page_cgroup() is not required because all
2302 * file-stat operations happen after a page is attached to radix-tree. There
2303 * are no race with "charge".
2305 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2306 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2307 * if there are race with "uncharge". Statistics itself is properly handled
2310 * Considering "move", this is an only case we see a race. To make the race
2311 * small, we check mm->moving_account and detect there are possibility of race
2312 * If there is, we take a lock.
2315 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2316 bool *locked
, unsigned long *flags
)
2318 struct mem_cgroup
*memcg
;
2319 struct page_cgroup
*pc
;
2321 pc
= lookup_page_cgroup(page
);
2323 memcg
= pc
->mem_cgroup
;
2324 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2327 * If this memory cgroup is not under account moving, we don't
2328 * need to take move_lock_mem_cgroup(). Because we already hold
2329 * rcu_read_lock(), any calls to move_account will be delayed until
2330 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2332 if (!mem_cgroup_stolen(memcg
))
2335 move_lock_mem_cgroup(memcg
, flags
);
2336 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2337 move_unlock_mem_cgroup(memcg
, flags
);
2343 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2345 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2348 * It's guaranteed that pc->mem_cgroup never changes while
2349 * lock is held because a routine modifies pc->mem_cgroup
2350 * should take move_lock_mem_cgroup().
2352 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2355 void mem_cgroup_update_page_stat(struct page
*page
,
2356 enum mem_cgroup_stat_index idx
, int val
)
2358 struct mem_cgroup
*memcg
;
2359 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2360 unsigned long uninitialized_var(flags
);
2362 if (mem_cgroup_disabled())
2365 VM_BUG_ON(!rcu_read_lock_held());
2366 memcg
= pc
->mem_cgroup
;
2367 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2370 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2374 * size of first charge trial. "32" comes from vmscan.c's magic value.
2375 * TODO: maybe necessary to use big numbers in big irons.
2377 #define CHARGE_BATCH 32U
2378 struct memcg_stock_pcp
{
2379 struct mem_cgroup
*cached
; /* this never be root cgroup */
2380 unsigned int nr_pages
;
2381 struct work_struct work
;
2382 unsigned long flags
;
2383 #define FLUSHING_CACHED_CHARGE 0
2385 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2386 static DEFINE_MUTEX(percpu_charge_mutex
);
2389 * consume_stock: Try to consume stocked charge on this cpu.
2390 * @memcg: memcg to consume from.
2391 * @nr_pages: how many pages to charge.
2393 * The charges will only happen if @memcg matches the current cpu's memcg
2394 * stock, and at least @nr_pages are available in that stock. Failure to
2395 * service an allocation will refill the stock.
2397 * returns true if successful, false otherwise.
2399 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2401 struct memcg_stock_pcp
*stock
;
2404 if (nr_pages
> CHARGE_BATCH
)
2407 stock
= &get_cpu_var(memcg_stock
);
2408 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2409 stock
->nr_pages
-= nr_pages
;
2410 else /* need to call res_counter_charge */
2412 put_cpu_var(memcg_stock
);
2417 * Returns stocks cached in percpu to res_counter and reset cached information.
2419 static void drain_stock(struct memcg_stock_pcp
*stock
)
2421 struct mem_cgroup
*old
= stock
->cached
;
2423 if (stock
->nr_pages
) {
2424 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2426 res_counter_uncharge(&old
->res
, bytes
);
2427 if (do_swap_account
)
2428 res_counter_uncharge(&old
->memsw
, bytes
);
2429 stock
->nr_pages
= 0;
2431 stock
->cached
= NULL
;
2435 * This must be called under preempt disabled or must be called by
2436 * a thread which is pinned to local cpu.
2438 static void drain_local_stock(struct work_struct
*dummy
)
2440 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2442 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2445 static void __init
memcg_stock_init(void)
2449 for_each_possible_cpu(cpu
) {
2450 struct memcg_stock_pcp
*stock
=
2451 &per_cpu(memcg_stock
, cpu
);
2452 INIT_WORK(&stock
->work
, drain_local_stock
);
2457 * Cache charges(val) which is from res_counter, to local per_cpu area.
2458 * This will be consumed by consume_stock() function, later.
2460 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2462 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2464 if (stock
->cached
!= memcg
) { /* reset if necessary */
2466 stock
->cached
= memcg
;
2468 stock
->nr_pages
+= nr_pages
;
2469 put_cpu_var(memcg_stock
);
2473 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2474 * of the hierarchy under it. sync flag says whether we should block
2475 * until the work is done.
2477 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2481 /* Notify other cpus that system-wide "drain" is running */
2484 for_each_online_cpu(cpu
) {
2485 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2486 struct mem_cgroup
*memcg
;
2488 memcg
= stock
->cached
;
2489 if (!memcg
|| !stock
->nr_pages
)
2491 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2493 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2495 drain_local_stock(&stock
->work
);
2497 schedule_work_on(cpu
, &stock
->work
);
2505 for_each_online_cpu(cpu
) {
2506 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2507 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2508 flush_work(&stock
->work
);
2515 * Tries to drain stocked charges in other cpus. This function is asynchronous
2516 * and just put a work per cpu for draining localy on each cpu. Caller can
2517 * expects some charges will be back to res_counter later but cannot wait for
2520 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2523 * If someone calls draining, avoid adding more kworker runs.
2525 if (!mutex_trylock(&percpu_charge_mutex
))
2527 drain_all_stock(root_memcg
, false);
2528 mutex_unlock(&percpu_charge_mutex
);
2531 /* This is a synchronous drain interface. */
2532 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2534 /* called when force_empty is called */
2535 mutex_lock(&percpu_charge_mutex
);
2536 drain_all_stock(root_memcg
, true);
2537 mutex_unlock(&percpu_charge_mutex
);
2541 * This function drains percpu counter value from DEAD cpu and
2542 * move it to local cpu. Note that this function can be preempted.
2544 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2548 spin_lock(&memcg
->pcp_counter_lock
);
2549 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2550 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2552 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2553 memcg
->nocpu_base
.count
[i
] += x
;
2555 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2556 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2558 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2559 memcg
->nocpu_base
.events
[i
] += x
;
2561 spin_unlock(&memcg
->pcp_counter_lock
);
2564 static int memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2565 unsigned long action
,
2568 int cpu
= (unsigned long)hcpu
;
2569 struct memcg_stock_pcp
*stock
;
2570 struct mem_cgroup
*iter
;
2572 if (action
== CPU_ONLINE
)
2575 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2578 for_each_mem_cgroup(iter
)
2579 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2581 stock
= &per_cpu(memcg_stock
, cpu
);
2587 /* See __mem_cgroup_try_charge() for details */
2589 CHARGE_OK
, /* success */
2590 CHARGE_RETRY
, /* need to retry but retry is not bad */
2591 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2592 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2595 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2596 unsigned int nr_pages
, unsigned int min_pages
,
2599 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2600 struct mem_cgroup
*mem_over_limit
;
2601 struct res_counter
*fail_res
;
2602 unsigned long flags
= 0;
2605 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2608 if (!do_swap_account
)
2610 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2614 res_counter_uncharge(&memcg
->res
, csize
);
2615 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2616 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2618 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2620 * Never reclaim on behalf of optional batching, retry with a
2621 * single page instead.
2623 if (nr_pages
> min_pages
)
2624 return CHARGE_RETRY
;
2626 if (!(gfp_mask
& __GFP_WAIT
))
2627 return CHARGE_WOULDBLOCK
;
2629 if (gfp_mask
& __GFP_NORETRY
)
2630 return CHARGE_NOMEM
;
2632 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2633 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2634 return CHARGE_RETRY
;
2636 * Even though the limit is exceeded at this point, reclaim
2637 * may have been able to free some pages. Retry the charge
2638 * before killing the task.
2640 * Only for regular pages, though: huge pages are rather
2641 * unlikely to succeed so close to the limit, and we fall back
2642 * to regular pages anyway in case of failure.
2644 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2645 return CHARGE_RETRY
;
2648 * At task move, charge accounts can be doubly counted. So, it's
2649 * better to wait until the end of task_move if something is going on.
2651 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2652 return CHARGE_RETRY
;
2655 mem_cgroup_oom(mem_over_limit
, gfp_mask
, get_order(csize
));
2657 return CHARGE_NOMEM
;
2661 * __mem_cgroup_try_charge() does
2662 * 1. detect memcg to be charged against from passed *mm and *ptr,
2663 * 2. update res_counter
2664 * 3. call memory reclaim if necessary.
2666 * In some special case, if the task is fatal, fatal_signal_pending() or
2667 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2668 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2669 * as possible without any hazards. 2: all pages should have a valid
2670 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2671 * pointer, that is treated as a charge to root_mem_cgroup.
2673 * So __mem_cgroup_try_charge() will return
2674 * 0 ... on success, filling *ptr with a valid memcg pointer.
2675 * -ENOMEM ... charge failure because of resource limits.
2676 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2678 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2679 * the oom-killer can be invoked.
2681 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2683 unsigned int nr_pages
,
2684 struct mem_cgroup
**ptr
,
2687 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2688 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2689 struct mem_cgroup
*memcg
= NULL
;
2693 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2694 * in system level. So, allow to go ahead dying process in addition to
2697 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2698 || fatal_signal_pending(current
)))
2701 if (unlikely(task_in_memcg_oom(current
)))
2704 if (gfp_mask
& __GFP_NOFAIL
)
2707 if (*ptr
) { /* css should be a valid one */
2709 if (mem_cgroup_is_root(memcg
))
2711 if (consume_stock(memcg
, nr_pages
))
2713 css_get(&memcg
->css
);
2715 struct task_struct
*p
;
2718 p
= rcu_dereference(mm
->owner
);
2720 * Because we don't have task_lock(), "p" can exit.
2721 * In that case, "memcg" can point to root or p can be NULL with
2722 * race with swapoff. Then, we have small risk of mis-accouning.
2723 * But such kind of mis-account by race always happens because
2724 * we don't have cgroup_mutex(). It's overkill and we allo that
2726 * (*) swapoff at el will charge against mm-struct not against
2727 * task-struct. So, mm->owner can be NULL.
2729 memcg
= mem_cgroup_from_task(p
);
2731 memcg
= root_mem_cgroup
;
2732 if (mem_cgroup_is_root(memcg
)) {
2736 if (consume_stock(memcg
, nr_pages
)) {
2738 * It seems dagerous to access memcg without css_get().
2739 * But considering how consume_stok works, it's not
2740 * necessary. If consume_stock success, some charges
2741 * from this memcg are cached on this cpu. So, we
2742 * don't need to call css_get()/css_tryget() before
2743 * calling consume_stock().
2748 /* after here, we may be blocked. we need to get refcnt */
2749 if (!css_tryget(&memcg
->css
)) {
2757 bool invoke_oom
= oom
&& !nr_oom_retries
;
2759 /* If killed, bypass charge */
2760 if (fatal_signal_pending(current
)) {
2761 css_put(&memcg
->css
);
2765 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
,
2766 nr_pages
, invoke_oom
);
2770 case CHARGE_RETRY
: /* not in OOM situation but retry */
2772 css_put(&memcg
->css
);
2775 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2776 css_put(&memcg
->css
);
2778 case CHARGE_NOMEM
: /* OOM routine works */
2779 if (!oom
|| invoke_oom
) {
2780 css_put(&memcg
->css
);
2786 } while (ret
!= CHARGE_OK
);
2788 if (batch
> nr_pages
)
2789 refill_stock(memcg
, batch
- nr_pages
);
2790 css_put(&memcg
->css
);
2795 if (!(gfp_mask
& __GFP_NOFAIL
)) {
2800 *ptr
= root_mem_cgroup
;
2805 * Somemtimes we have to undo a charge we got by try_charge().
2806 * This function is for that and do uncharge, put css's refcnt.
2807 * gotten by try_charge().
2809 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2810 unsigned int nr_pages
)
2812 if (!mem_cgroup_is_root(memcg
)) {
2813 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2815 res_counter_uncharge(&memcg
->res
, bytes
);
2816 if (do_swap_account
)
2817 res_counter_uncharge(&memcg
->memsw
, bytes
);
2822 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2823 * This is useful when moving usage to parent cgroup.
2825 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2826 unsigned int nr_pages
)
2828 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2830 if (mem_cgroup_is_root(memcg
))
2833 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2834 if (do_swap_account
)
2835 res_counter_uncharge_until(&memcg
->memsw
,
2836 memcg
->memsw
.parent
, bytes
);
2840 * A helper function to get mem_cgroup from ID. must be called under
2841 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2842 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2843 * called against removed memcg.)
2845 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2847 /* ID 0 is unused ID */
2850 return mem_cgroup_from_id(id
);
2853 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2855 struct mem_cgroup
*memcg
= NULL
;
2856 struct page_cgroup
*pc
;
2860 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
2862 pc
= lookup_page_cgroup(page
);
2863 lock_page_cgroup(pc
);
2864 if (PageCgroupUsed(pc
)) {
2865 memcg
= pc
->mem_cgroup
;
2866 if (memcg
&& !css_tryget(&memcg
->css
))
2868 } else if (PageSwapCache(page
)) {
2869 ent
.val
= page_private(page
);
2870 id
= lookup_swap_cgroup_id(ent
);
2872 memcg
= mem_cgroup_lookup(id
);
2873 if (memcg
&& !css_tryget(&memcg
->css
))
2877 unlock_page_cgroup(pc
);
2881 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2883 unsigned int nr_pages
,
2884 enum charge_type ctype
,
2887 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2888 struct zone
*uninitialized_var(zone
);
2889 struct lruvec
*lruvec
;
2890 bool was_on_lru
= false;
2893 lock_page_cgroup(pc
);
2894 VM_BUG_ON_PAGE(PageCgroupUsed(pc
), page
);
2896 * we don't need page_cgroup_lock about tail pages, becase they are not
2897 * accessed by any other context at this point.
2901 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2902 * may already be on some other mem_cgroup's LRU. Take care of it.
2905 zone
= page_zone(page
);
2906 spin_lock_irq(&zone
->lru_lock
);
2907 if (PageLRU(page
)) {
2908 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2910 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2915 pc
->mem_cgroup
= memcg
;
2917 * We access a page_cgroup asynchronously without lock_page_cgroup().
2918 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2919 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2920 * before USED bit, we need memory barrier here.
2921 * See mem_cgroup_add_lru_list(), etc.
2924 SetPageCgroupUsed(pc
);
2928 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2929 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2931 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2933 spin_unlock_irq(&zone
->lru_lock
);
2936 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2941 mem_cgroup_charge_statistics(memcg
, page
, anon
, nr_pages
);
2942 unlock_page_cgroup(pc
);
2945 * "charge_statistics" updated event counter. Then, check it.
2946 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2947 * if they exceeds softlimit.
2949 memcg_check_events(memcg
, page
);
2952 static DEFINE_MUTEX(set_limit_mutex
);
2954 #ifdef CONFIG_MEMCG_KMEM
2955 static DEFINE_MUTEX(activate_kmem_mutex
);
2957 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2959 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
2960 memcg_kmem_is_active(memcg
);
2964 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
2965 * in the memcg_cache_params struct.
2967 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
2969 struct kmem_cache
*cachep
;
2971 VM_BUG_ON(p
->is_root_cache
);
2972 cachep
= p
->root_cache
;
2973 return cache_from_memcg_idx(cachep
, memcg_cache_id(p
->memcg
));
2976 #ifdef CONFIG_SLABINFO
2977 static int mem_cgroup_slabinfo_read(struct seq_file
*m
, void *v
)
2979 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
2980 struct memcg_cache_params
*params
;
2982 if (!memcg_can_account_kmem(memcg
))
2985 print_slabinfo_header(m
);
2987 mutex_lock(&memcg
->slab_caches_mutex
);
2988 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
2989 cache_show(memcg_params_to_cache(params
), m
);
2990 mutex_unlock(&memcg
->slab_caches_mutex
);
2996 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
2998 struct res_counter
*fail_res
;
2999 struct mem_cgroup
*_memcg
;
3002 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
3007 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
3008 &_memcg
, oom_gfp_allowed(gfp
));
3010 if (ret
== -EINTR
) {
3012 * __mem_cgroup_try_charge() chosed to bypass to root due to
3013 * OOM kill or fatal signal. Since our only options are to
3014 * either fail the allocation or charge it to this cgroup, do
3015 * it as a temporary condition. But we can't fail. From a
3016 * kmem/slab perspective, the cache has already been selected,
3017 * by mem_cgroup_kmem_get_cache(), so it is too late to change
3020 * This condition will only trigger if the task entered
3021 * memcg_charge_kmem in a sane state, but was OOM-killed during
3022 * __mem_cgroup_try_charge() above. Tasks that were already
3023 * dying when the allocation triggers should have been already
3024 * directed to the root cgroup in memcontrol.h
3026 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
3027 if (do_swap_account
)
3028 res_counter_charge_nofail(&memcg
->memsw
, size
,
3032 res_counter_uncharge(&memcg
->kmem
, size
);
3037 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
3039 res_counter_uncharge(&memcg
->res
, size
);
3040 if (do_swap_account
)
3041 res_counter_uncharge(&memcg
->memsw
, size
);
3044 if (res_counter_uncharge(&memcg
->kmem
, size
))
3048 * Releases a reference taken in kmem_cgroup_css_offline in case
3049 * this last uncharge is racing with the offlining code or it is
3050 * outliving the memcg existence.
3052 * The memory barrier imposed by test&clear is paired with the
3053 * explicit one in memcg_kmem_mark_dead().
3055 if (memcg_kmem_test_and_clear_dead(memcg
))
3056 css_put(&memcg
->css
);
3060 * helper for acessing a memcg's index. It will be used as an index in the
3061 * child cache array in kmem_cache, and also to derive its name. This function
3062 * will return -1 when this is not a kmem-limited memcg.
3064 int memcg_cache_id(struct mem_cgroup
*memcg
)
3066 return memcg
? memcg
->kmemcg_id
: -1;
3069 static size_t memcg_caches_array_size(int num_groups
)
3072 if (num_groups
<= 0)
3075 size
= 2 * num_groups
;
3076 if (size
< MEMCG_CACHES_MIN_SIZE
)
3077 size
= MEMCG_CACHES_MIN_SIZE
;
3078 else if (size
> MEMCG_CACHES_MAX_SIZE
)
3079 size
= MEMCG_CACHES_MAX_SIZE
;
3085 * We should update the current array size iff all caches updates succeed. This
3086 * can only be done from the slab side. The slab mutex needs to be held when
3089 void memcg_update_array_size(int num
)
3091 if (num
> memcg_limited_groups_array_size
)
3092 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3095 static void kmem_cache_destroy_work_func(struct work_struct
*w
);
3097 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3099 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3101 VM_BUG_ON(!is_root_cache(s
));
3103 if (num_groups
> memcg_limited_groups_array_size
) {
3105 struct memcg_cache_params
*new_params
;
3106 ssize_t size
= memcg_caches_array_size(num_groups
);
3108 size
*= sizeof(void *);
3109 size
+= offsetof(struct memcg_cache_params
, memcg_caches
);
3111 new_params
= kzalloc(size
, GFP_KERNEL
);
3115 new_params
->is_root_cache
= true;
3118 * There is the chance it will be bigger than
3119 * memcg_limited_groups_array_size, if we failed an allocation
3120 * in a cache, in which case all caches updated before it, will
3121 * have a bigger array.
3123 * But if that is the case, the data after
3124 * memcg_limited_groups_array_size is certainly unused
3126 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3127 if (!cur_params
->memcg_caches
[i
])
3129 new_params
->memcg_caches
[i
] =
3130 cur_params
->memcg_caches
[i
];
3134 * Ideally, we would wait until all caches succeed, and only
3135 * then free the old one. But this is not worth the extra
3136 * pointer per-cache we'd have to have for this.
3138 * It is not a big deal if some caches are left with a size
3139 * bigger than the others. And all updates will reset this
3142 rcu_assign_pointer(s
->memcg_params
, new_params
);
3144 kfree_rcu(cur_params
, rcu_head
);
3149 int memcg_alloc_cache_params(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3150 struct kmem_cache
*root_cache
)
3154 if (!memcg_kmem_enabled())
3158 size
= offsetof(struct memcg_cache_params
, memcg_caches
);
3159 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3161 size
= sizeof(struct memcg_cache_params
);
3163 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3164 if (!s
->memcg_params
)
3168 s
->memcg_params
->memcg
= memcg
;
3169 s
->memcg_params
->root_cache
= root_cache
;
3170 INIT_WORK(&s
->memcg_params
->destroy
,
3171 kmem_cache_destroy_work_func
);
3173 s
->memcg_params
->is_root_cache
= true;
3178 void memcg_free_cache_params(struct kmem_cache
*s
)
3180 kfree(s
->memcg_params
);
3183 void memcg_register_cache(struct kmem_cache
*s
)
3185 struct kmem_cache
*root
;
3186 struct mem_cgroup
*memcg
;
3189 if (is_root_cache(s
))
3193 * Holding the slab_mutex assures nobody will touch the memcg_caches
3194 * array while we are modifying it.
3196 lockdep_assert_held(&slab_mutex
);
3198 root
= s
->memcg_params
->root_cache
;
3199 memcg
= s
->memcg_params
->memcg
;
3200 id
= memcg_cache_id(memcg
);
3202 css_get(&memcg
->css
);
3206 * Since readers won't lock (see cache_from_memcg_idx()), we need a
3207 * barrier here to ensure nobody will see the kmem_cache partially
3213 * Initialize the pointer to this cache in its parent's memcg_params
3214 * before adding it to the memcg_slab_caches list, otherwise we can
3215 * fail to convert memcg_params_to_cache() while traversing the list.
3217 VM_BUG_ON(root
->memcg_params
->memcg_caches
[id
]);
3218 root
->memcg_params
->memcg_caches
[id
] = s
;
3220 mutex_lock(&memcg
->slab_caches_mutex
);
3221 list_add(&s
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
3222 mutex_unlock(&memcg
->slab_caches_mutex
);
3225 void memcg_unregister_cache(struct kmem_cache
*s
)
3227 struct kmem_cache
*root
;
3228 struct mem_cgroup
*memcg
;
3231 if (is_root_cache(s
))
3235 * Holding the slab_mutex assures nobody will touch the memcg_caches
3236 * array while we are modifying it.
3238 lockdep_assert_held(&slab_mutex
);
3240 root
= s
->memcg_params
->root_cache
;
3241 memcg
= s
->memcg_params
->memcg
;
3242 id
= memcg_cache_id(memcg
);
3244 mutex_lock(&memcg
->slab_caches_mutex
);
3245 list_del(&s
->memcg_params
->list
);
3246 mutex_unlock(&memcg
->slab_caches_mutex
);
3249 * Clear the pointer to this cache in its parent's memcg_params only
3250 * after removing it from the memcg_slab_caches list, otherwise we can
3251 * fail to convert memcg_params_to_cache() while traversing the list.
3253 VM_BUG_ON(!root
->memcg_params
->memcg_caches
[id
]);
3254 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3256 css_put(&memcg
->css
);
3260 * During the creation a new cache, we need to disable our accounting mechanism
3261 * altogether. This is true even if we are not creating, but rather just
3262 * enqueing new caches to be created.
3264 * This is because that process will trigger allocations; some visible, like
3265 * explicit kmallocs to auxiliary data structures, name strings and internal
3266 * cache structures; some well concealed, like INIT_WORK() that can allocate
3267 * objects during debug.
3269 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3270 * to it. This may not be a bounded recursion: since the first cache creation
3271 * failed to complete (waiting on the allocation), we'll just try to create the
3272 * cache again, failing at the same point.
3274 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3275 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3276 * inside the following two functions.
3278 static inline void memcg_stop_kmem_account(void)
3280 VM_BUG_ON(!current
->mm
);
3281 current
->memcg_kmem_skip_account
++;
3284 static inline void memcg_resume_kmem_account(void)
3286 VM_BUG_ON(!current
->mm
);
3287 current
->memcg_kmem_skip_account
--;
3290 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3292 struct kmem_cache
*cachep
;
3293 struct memcg_cache_params
*p
;
3295 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3297 cachep
= memcg_params_to_cache(p
);
3300 * If we get down to 0 after shrink, we could delete right away.
3301 * However, memcg_release_pages() already puts us back in the workqueue
3302 * in that case. If we proceed deleting, we'll get a dangling
3303 * reference, and removing the object from the workqueue in that case
3304 * is unnecessary complication. We are not a fast path.
3306 * Note that this case is fundamentally different from racing with
3307 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3308 * kmem_cache_shrink, not only we would be reinserting a dead cache
3309 * into the queue, but doing so from inside the worker racing to
3312 * So if we aren't down to zero, we'll just schedule a worker and try
3315 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0)
3316 kmem_cache_shrink(cachep
);
3318 kmem_cache_destroy(cachep
);
3321 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3323 if (!cachep
->memcg_params
->dead
)
3327 * There are many ways in which we can get here.
3329 * We can get to a memory-pressure situation while the delayed work is
3330 * still pending to run. The vmscan shrinkers can then release all
3331 * cache memory and get us to destruction. If this is the case, we'll
3332 * be executed twice, which is a bug (the second time will execute over
3333 * bogus data). In this case, cancelling the work should be fine.
3335 * But we can also get here from the worker itself, if
3336 * kmem_cache_shrink is enough to shake all the remaining objects and
3337 * get the page count to 0. In this case, we'll deadlock if we try to
3338 * cancel the work (the worker runs with an internal lock held, which
3339 * is the same lock we would hold for cancel_work_sync().)
3341 * Since we can't possibly know who got us here, just refrain from
3342 * running if there is already work pending
3344 if (work_pending(&cachep
->memcg_params
->destroy
))
3347 * We have to defer the actual destroying to a workqueue, because
3348 * we might currently be in a context that cannot sleep.
3350 schedule_work(&cachep
->memcg_params
->destroy
);
3353 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3354 struct kmem_cache
*s
)
3356 struct kmem_cache
*new = NULL
;
3357 static char *tmp_path
= NULL
, *tmp_name
= NULL
;
3358 static DEFINE_MUTEX(mutex
); /* protects tmp_name */
3360 BUG_ON(!memcg_can_account_kmem(memcg
));
3364 * kmem_cache_create_memcg duplicates the given name and
3365 * cgroup_name for this name requires RCU context.
3366 * This static temporary buffer is used to prevent from
3367 * pointless shortliving allocation.
3369 if (!tmp_path
|| !tmp_name
) {
3371 tmp_path
= kmalloc(PATH_MAX
, GFP_KERNEL
);
3373 tmp_name
= kmalloc(NAME_MAX
+ 1, GFP_KERNEL
);
3374 if (!tmp_path
|| !tmp_name
)
3378 cgroup_name(memcg
->css
.cgroup
, tmp_name
, NAME_MAX
+ 1);
3379 snprintf(tmp_path
, PATH_MAX
, "%s(%d:%s)", s
->name
,
3380 memcg_cache_id(memcg
), tmp_name
);
3382 new = kmem_cache_create_memcg(memcg
, tmp_path
, s
->object_size
, s
->align
,
3383 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3385 new->allocflags
|= __GFP_KMEMCG
;
3389 mutex_unlock(&mutex
);
3393 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3395 struct kmem_cache
*c
;
3398 if (!s
->memcg_params
)
3400 if (!s
->memcg_params
->is_root_cache
)
3404 * If the cache is being destroyed, we trust that there is no one else
3405 * requesting objects from it. Even if there are, the sanity checks in
3406 * kmem_cache_destroy should caught this ill-case.
3408 * Still, we don't want anyone else freeing memcg_caches under our
3409 * noses, which can happen if a new memcg comes to life. As usual,
3410 * we'll take the activate_kmem_mutex to protect ourselves against
3413 mutex_lock(&activate_kmem_mutex
);
3414 for_each_memcg_cache_index(i
) {
3415 c
= cache_from_memcg_idx(s
, i
);
3420 * We will now manually delete the caches, so to avoid races
3421 * we need to cancel all pending destruction workers and
3422 * proceed with destruction ourselves.
3424 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3425 * and that could spawn the workers again: it is likely that
3426 * the cache still have active pages until this very moment.
3427 * This would lead us back to mem_cgroup_destroy_cache.
3429 * But that will not execute at all if the "dead" flag is not
3430 * set, so flip it down to guarantee we are in control.
3432 c
->memcg_params
->dead
= false;
3433 cancel_work_sync(&c
->memcg_params
->destroy
);
3434 kmem_cache_destroy(c
);
3436 mutex_unlock(&activate_kmem_mutex
);
3439 struct create_work
{
3440 struct mem_cgroup
*memcg
;
3441 struct kmem_cache
*cachep
;
3442 struct work_struct work
;
3445 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3447 struct kmem_cache
*cachep
;
3448 struct memcg_cache_params
*params
;
3450 if (!memcg_kmem_is_active(memcg
))
3453 mutex_lock(&memcg
->slab_caches_mutex
);
3454 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3455 cachep
= memcg_params_to_cache(params
);
3456 cachep
->memcg_params
->dead
= true;
3457 schedule_work(&cachep
->memcg_params
->destroy
);
3459 mutex_unlock(&memcg
->slab_caches_mutex
);
3462 static void memcg_create_cache_work_func(struct work_struct
*w
)
3464 struct create_work
*cw
;
3466 cw
= container_of(w
, struct create_work
, work
);
3467 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3468 css_put(&cw
->memcg
->css
);
3473 * Enqueue the creation of a per-memcg kmem_cache.
3475 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3476 struct kmem_cache
*cachep
)
3478 struct create_work
*cw
;
3480 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3482 css_put(&memcg
->css
);
3487 cw
->cachep
= cachep
;
3489 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3490 schedule_work(&cw
->work
);
3493 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3494 struct kmem_cache
*cachep
)
3497 * We need to stop accounting when we kmalloc, because if the
3498 * corresponding kmalloc cache is not yet created, the first allocation
3499 * in __memcg_create_cache_enqueue will recurse.
3501 * However, it is better to enclose the whole function. Depending on
3502 * the debugging options enabled, INIT_WORK(), for instance, can
3503 * trigger an allocation. This too, will make us recurse. Because at
3504 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3505 * the safest choice is to do it like this, wrapping the whole function.
3507 memcg_stop_kmem_account();
3508 __memcg_create_cache_enqueue(memcg
, cachep
);
3509 memcg_resume_kmem_account();
3512 * Return the kmem_cache we're supposed to use for a slab allocation.
3513 * We try to use the current memcg's version of the cache.
3515 * If the cache does not exist yet, if we are the first user of it,
3516 * we either create it immediately, if possible, or create it asynchronously
3518 * In the latter case, we will let the current allocation go through with
3519 * the original cache.
3521 * Can't be called in interrupt context or from kernel threads.
3522 * This function needs to be called with rcu_read_lock() held.
3524 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3527 struct mem_cgroup
*memcg
;
3528 struct kmem_cache
*memcg_cachep
;
3530 VM_BUG_ON(!cachep
->memcg_params
);
3531 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3533 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3537 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3539 if (!memcg_can_account_kmem(memcg
))
3542 memcg_cachep
= cache_from_memcg_idx(cachep
, memcg_cache_id(memcg
));
3543 if (likely(memcg_cachep
)) {
3544 cachep
= memcg_cachep
;
3548 /* The corresponding put will be done in the workqueue. */
3549 if (!css_tryget(&memcg
->css
))
3554 * If we are in a safe context (can wait, and not in interrupt
3555 * context), we could be be predictable and return right away.
3556 * This would guarantee that the allocation being performed
3557 * already belongs in the new cache.
3559 * However, there are some clashes that can arrive from locking.
3560 * For instance, because we acquire the slab_mutex while doing
3561 * kmem_cache_dup, this means no further allocation could happen
3562 * with the slab_mutex held.
3564 * Also, because cache creation issue get_online_cpus(), this
3565 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3566 * that ends up reversed during cpu hotplug. (cpuset allocates
3567 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3568 * better to defer everything.
3570 memcg_create_cache_enqueue(memcg
, cachep
);
3576 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3579 * We need to verify if the allocation against current->mm->owner's memcg is
3580 * possible for the given order. But the page is not allocated yet, so we'll
3581 * need a further commit step to do the final arrangements.
3583 * It is possible for the task to switch cgroups in this mean time, so at
3584 * commit time, we can't rely on task conversion any longer. We'll then use
3585 * the handle argument to return to the caller which cgroup we should commit
3586 * against. We could also return the memcg directly and avoid the pointer
3587 * passing, but a boolean return value gives better semantics considering
3588 * the compiled-out case as well.
3590 * Returning true means the allocation is possible.
3593 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3595 struct mem_cgroup
*memcg
;
3601 * Disabling accounting is only relevant for some specific memcg
3602 * internal allocations. Therefore we would initially not have such
3603 * check here, since direct calls to the page allocator that are marked
3604 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3605 * concerned with cache allocations, and by having this test at
3606 * memcg_kmem_get_cache, we are already able to relay the allocation to
3607 * the root cache and bypass the memcg cache altogether.
3609 * There is one exception, though: the SLUB allocator does not create
3610 * large order caches, but rather service large kmallocs directly from
3611 * the page allocator. Therefore, the following sequence when backed by
3612 * the SLUB allocator:
3614 * memcg_stop_kmem_account();
3615 * kmalloc(<large_number>)
3616 * memcg_resume_kmem_account();
3618 * would effectively ignore the fact that we should skip accounting,
3619 * since it will drive us directly to this function without passing
3620 * through the cache selector memcg_kmem_get_cache. Such large
3621 * allocations are extremely rare but can happen, for instance, for the
3622 * cache arrays. We bring this test here.
3624 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3627 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3630 * very rare case described in mem_cgroup_from_task. Unfortunately there
3631 * isn't much we can do without complicating this too much, and it would
3632 * be gfp-dependent anyway. Just let it go
3634 if (unlikely(!memcg
))
3637 if (!memcg_can_account_kmem(memcg
)) {
3638 css_put(&memcg
->css
);
3642 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3646 css_put(&memcg
->css
);
3650 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3653 struct page_cgroup
*pc
;
3655 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3657 /* The page allocation failed. Revert */
3659 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3663 pc
= lookup_page_cgroup(page
);
3664 lock_page_cgroup(pc
);
3665 pc
->mem_cgroup
= memcg
;
3666 SetPageCgroupUsed(pc
);
3667 unlock_page_cgroup(pc
);
3670 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3672 struct mem_cgroup
*memcg
= NULL
;
3673 struct page_cgroup
*pc
;
3676 pc
= lookup_page_cgroup(page
);
3678 * Fast unlocked return. Theoretically might have changed, have to
3679 * check again after locking.
3681 if (!PageCgroupUsed(pc
))
3684 lock_page_cgroup(pc
);
3685 if (PageCgroupUsed(pc
)) {
3686 memcg
= pc
->mem_cgroup
;
3687 ClearPageCgroupUsed(pc
);
3689 unlock_page_cgroup(pc
);
3692 * We trust that only if there is a memcg associated with the page, it
3693 * is a valid allocation
3698 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
3699 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3702 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3705 #endif /* CONFIG_MEMCG_KMEM */
3707 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3709 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3711 * Because tail pages are not marked as "used", set it. We're under
3712 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3713 * charge/uncharge will be never happen and move_account() is done under
3714 * compound_lock(), so we don't have to take care of races.
3716 void mem_cgroup_split_huge_fixup(struct page
*head
)
3718 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3719 struct page_cgroup
*pc
;
3720 struct mem_cgroup
*memcg
;
3723 if (mem_cgroup_disabled())
3726 memcg
= head_pc
->mem_cgroup
;
3727 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3729 pc
->mem_cgroup
= memcg
;
3730 smp_wmb();/* see __commit_charge() */
3731 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3733 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
3736 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3739 * mem_cgroup_move_account - move account of the page
3741 * @nr_pages: number of regular pages (>1 for huge pages)
3742 * @pc: page_cgroup of the page.
3743 * @from: mem_cgroup which the page is moved from.
3744 * @to: mem_cgroup which the page is moved to. @from != @to.
3746 * The caller must confirm following.
3747 * - page is not on LRU (isolate_page() is useful.)
3748 * - compound_lock is held when nr_pages > 1
3750 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3753 static int mem_cgroup_move_account(struct page
*page
,
3754 unsigned int nr_pages
,
3755 struct page_cgroup
*pc
,
3756 struct mem_cgroup
*from
,
3757 struct mem_cgroup
*to
)
3759 unsigned long flags
;
3761 bool anon
= PageAnon(page
);
3763 VM_BUG_ON(from
== to
);
3764 VM_BUG_ON_PAGE(PageLRU(page
), page
);
3766 * The page is isolated from LRU. So, collapse function
3767 * will not handle this page. But page splitting can happen.
3768 * Do this check under compound_page_lock(). The caller should
3772 if (nr_pages
> 1 && !PageTransHuge(page
))
3775 lock_page_cgroup(pc
);
3778 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3781 move_lock_mem_cgroup(from
, &flags
);
3783 if (!anon
&& page_mapped(page
)) {
3784 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
3786 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
3790 if (PageWriteback(page
)) {
3791 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
3793 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
3797 mem_cgroup_charge_statistics(from
, page
, anon
, -nr_pages
);
3799 /* caller should have done css_get */
3800 pc
->mem_cgroup
= to
;
3801 mem_cgroup_charge_statistics(to
, page
, anon
, nr_pages
);
3802 move_unlock_mem_cgroup(from
, &flags
);
3805 unlock_page_cgroup(pc
);
3809 memcg_check_events(to
, page
);
3810 memcg_check_events(from
, page
);
3816 * mem_cgroup_move_parent - moves page to the parent group
3817 * @page: the page to move
3818 * @pc: page_cgroup of the page
3819 * @child: page's cgroup
3821 * move charges to its parent or the root cgroup if the group has no
3822 * parent (aka use_hierarchy==0).
3823 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3824 * mem_cgroup_move_account fails) the failure is always temporary and
3825 * it signals a race with a page removal/uncharge or migration. In the
3826 * first case the page is on the way out and it will vanish from the LRU
3827 * on the next attempt and the call should be retried later.
3828 * Isolation from the LRU fails only if page has been isolated from
3829 * the LRU since we looked at it and that usually means either global
3830 * reclaim or migration going on. The page will either get back to the
3832 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3833 * (!PageCgroupUsed) or moved to a different group. The page will
3834 * disappear in the next attempt.
3836 static int mem_cgroup_move_parent(struct page
*page
,
3837 struct page_cgroup
*pc
,
3838 struct mem_cgroup
*child
)
3840 struct mem_cgroup
*parent
;
3841 unsigned int nr_pages
;
3842 unsigned long uninitialized_var(flags
);
3845 VM_BUG_ON(mem_cgroup_is_root(child
));
3848 if (!get_page_unless_zero(page
))
3850 if (isolate_lru_page(page
))
3853 nr_pages
= hpage_nr_pages(page
);
3855 parent
= parent_mem_cgroup(child
);
3857 * If no parent, move charges to root cgroup.
3860 parent
= root_mem_cgroup
;
3863 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
3864 flags
= compound_lock_irqsave(page
);
3867 ret
= mem_cgroup_move_account(page
, nr_pages
,
3870 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3873 compound_unlock_irqrestore(page
, flags
);
3874 putback_lru_page(page
);
3881 int mem_cgroup_newpage_charge(struct page
*page
,
3882 struct mm_struct
*mm
, gfp_t gfp_mask
)
3884 struct mem_cgroup
*memcg
= NULL
;
3885 unsigned int nr_pages
= 1;
3889 if (mem_cgroup_disabled())
3892 VM_BUG_ON_PAGE(page_mapped(page
), page
);
3893 VM_BUG_ON_PAGE(page
->mapping
&& !PageAnon(page
), page
);
3896 if (PageTransHuge(page
)) {
3897 nr_pages
<<= compound_order(page
);
3898 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
3900 * Never OOM-kill a process for a huge page. The
3901 * fault handler will fall back to regular pages.
3906 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
3909 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
,
3910 MEM_CGROUP_CHARGE_TYPE_ANON
, false);
3915 * While swap-in, try_charge -> commit or cancel, the page is locked.
3916 * And when try_charge() successfully returns, one refcnt to memcg without
3917 * struct page_cgroup is acquired. This refcnt will be consumed by
3918 * "commit()" or removed by "cancel()"
3920 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
3923 struct mem_cgroup
**memcgp
)
3925 struct mem_cgroup
*memcg
;
3926 struct page_cgroup
*pc
;
3929 pc
= lookup_page_cgroup(page
);
3931 * Every swap fault against a single page tries to charge the
3932 * page, bail as early as possible. shmem_unuse() encounters
3933 * already charged pages, too. The USED bit is protected by
3934 * the page lock, which serializes swap cache removal, which
3935 * in turn serializes uncharging.
3937 if (PageCgroupUsed(pc
))
3939 if (!do_swap_account
)
3941 memcg
= try_get_mem_cgroup_from_page(page
);
3945 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
3946 css_put(&memcg
->css
);
3951 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
3957 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
3958 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
3961 if (mem_cgroup_disabled())
3964 * A racing thread's fault, or swapoff, may have already
3965 * updated the pte, and even removed page from swap cache: in
3966 * those cases unuse_pte()'s pte_same() test will fail; but
3967 * there's also a KSM case which does need to charge the page.
3969 if (!PageSwapCache(page
)) {
3972 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
3977 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
3980 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
3982 if (mem_cgroup_disabled())
3986 __mem_cgroup_cancel_charge(memcg
, 1);
3990 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
3991 enum charge_type ctype
)
3993 if (mem_cgroup_disabled())
3998 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
4000 * Now swap is on-memory. This means this page may be
4001 * counted both as mem and swap....double count.
4002 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
4003 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
4004 * may call delete_from_swap_cache() before reach here.
4006 if (do_swap_account
&& PageSwapCache(page
)) {
4007 swp_entry_t ent
= {.val
= page_private(page
)};
4008 mem_cgroup_uncharge_swap(ent
);
4012 void mem_cgroup_commit_charge_swapin(struct page
*page
,
4013 struct mem_cgroup
*memcg
)
4015 __mem_cgroup_commit_charge_swapin(page
, memcg
,
4016 MEM_CGROUP_CHARGE_TYPE_ANON
);
4019 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
4022 struct mem_cgroup
*memcg
= NULL
;
4023 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4026 if (mem_cgroup_disabled())
4028 if (PageCompound(page
))
4031 if (!PageSwapCache(page
)) {
4033 * Page cache insertions can happen without an actual
4034 * task context, e.g. during disk probing on boot.
4037 memcg
= root_mem_cgroup
;
4038 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, &memcg
, true);
4040 __mem_cgroup_commit_charge(memcg
, page
, 1, type
, false);
4041 } else { /* page is swapcache/shmem */
4042 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
4045 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
4050 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
4051 unsigned int nr_pages
,
4052 const enum charge_type ctype
)
4054 struct memcg_batch_info
*batch
= NULL
;
4055 bool uncharge_memsw
= true;
4057 /* If swapout, usage of swap doesn't decrease */
4058 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
4059 uncharge_memsw
= false;
4061 batch
= ¤t
->memcg_batch
;
4063 * In usual, we do css_get() when we remember memcg pointer.
4064 * But in this case, we keep res->usage until end of a series of
4065 * uncharges. Then, it's ok to ignore memcg's refcnt.
4068 batch
->memcg
= memcg
;
4070 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
4071 * In those cases, all pages freed continuously can be expected to be in
4072 * the same cgroup and we have chance to coalesce uncharges.
4073 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
4074 * because we want to do uncharge as soon as possible.
4077 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
4078 goto direct_uncharge
;
4081 goto direct_uncharge
;
4084 * In typical case, batch->memcg == mem. This means we can
4085 * merge a series of uncharges to an uncharge of res_counter.
4086 * If not, we uncharge res_counter ony by one.
4088 if (batch
->memcg
!= memcg
)
4089 goto direct_uncharge
;
4090 /* remember freed charge and uncharge it later */
4093 batch
->memsw_nr_pages
++;
4096 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
4098 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
4099 if (unlikely(batch
->memcg
!= memcg
))
4100 memcg_oom_recover(memcg
);
4104 * uncharge if !page_mapped(page)
4106 static struct mem_cgroup
*
4107 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
4110 struct mem_cgroup
*memcg
= NULL
;
4111 unsigned int nr_pages
= 1;
4112 struct page_cgroup
*pc
;
4115 if (mem_cgroup_disabled())
4118 if (PageTransHuge(page
)) {
4119 nr_pages
<<= compound_order(page
);
4120 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
4123 * Check if our page_cgroup is valid
4125 pc
= lookup_page_cgroup(page
);
4126 if (unlikely(!PageCgroupUsed(pc
)))
4129 lock_page_cgroup(pc
);
4131 memcg
= pc
->mem_cgroup
;
4133 if (!PageCgroupUsed(pc
))
4136 anon
= PageAnon(page
);
4139 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4141 * Generally PageAnon tells if it's the anon statistics to be
4142 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4143 * used before page reached the stage of being marked PageAnon.
4147 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4148 /* See mem_cgroup_prepare_migration() */
4149 if (page_mapped(page
))
4152 * Pages under migration may not be uncharged. But
4153 * end_migration() /must/ be the one uncharging the
4154 * unused post-migration page and so it has to call
4155 * here with the migration bit still set. See the
4156 * res_counter handling below.
4158 if (!end_migration
&& PageCgroupMigration(pc
))
4161 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4162 if (!PageAnon(page
)) { /* Shared memory */
4163 if (page
->mapping
&& !page_is_file_cache(page
))
4165 } else if (page_mapped(page
)) /* Anon */
4172 mem_cgroup_charge_statistics(memcg
, page
, anon
, -nr_pages
);
4174 ClearPageCgroupUsed(pc
);
4176 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4177 * freed from LRU. This is safe because uncharged page is expected not
4178 * to be reused (freed soon). Exception is SwapCache, it's handled by
4179 * special functions.
4182 unlock_page_cgroup(pc
);
4184 * even after unlock, we have memcg->res.usage here and this memcg
4185 * will never be freed, so it's safe to call css_get().
4187 memcg_check_events(memcg
, page
);
4188 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4189 mem_cgroup_swap_statistics(memcg
, true);
4190 css_get(&memcg
->css
);
4193 * Migration does not charge the res_counter for the
4194 * replacement page, so leave it alone when phasing out the
4195 * page that is unused after the migration.
4197 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4198 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4203 unlock_page_cgroup(pc
);
4207 void mem_cgroup_uncharge_page(struct page
*page
)
4210 if (page_mapped(page
))
4212 VM_BUG_ON_PAGE(page
->mapping
&& !PageAnon(page
), page
);
4214 * If the page is in swap cache, uncharge should be deferred
4215 * to the swap path, which also properly accounts swap usage
4216 * and handles memcg lifetime.
4218 * Note that this check is not stable and reclaim may add the
4219 * page to swap cache at any time after this. However, if the
4220 * page is not in swap cache by the time page->mapcount hits
4221 * 0, there won't be any page table references to the swap
4222 * slot, and reclaim will free it and not actually write the
4225 if (PageSwapCache(page
))
4227 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4230 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4232 VM_BUG_ON_PAGE(page_mapped(page
), page
);
4233 VM_BUG_ON_PAGE(page
->mapping
, page
);
4234 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4238 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4239 * In that cases, pages are freed continuously and we can expect pages
4240 * are in the same memcg. All these calls itself limits the number of
4241 * pages freed at once, then uncharge_start/end() is called properly.
4242 * This may be called prural(2) times in a context,
4245 void mem_cgroup_uncharge_start(void)
4247 current
->memcg_batch
.do_batch
++;
4248 /* We can do nest. */
4249 if (current
->memcg_batch
.do_batch
== 1) {
4250 current
->memcg_batch
.memcg
= NULL
;
4251 current
->memcg_batch
.nr_pages
= 0;
4252 current
->memcg_batch
.memsw_nr_pages
= 0;
4256 void mem_cgroup_uncharge_end(void)
4258 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4260 if (!batch
->do_batch
)
4264 if (batch
->do_batch
) /* If stacked, do nothing. */
4270 * This "batch->memcg" is valid without any css_get/put etc...
4271 * bacause we hide charges behind us.
4273 if (batch
->nr_pages
)
4274 res_counter_uncharge(&batch
->memcg
->res
,
4275 batch
->nr_pages
* PAGE_SIZE
);
4276 if (batch
->memsw_nr_pages
)
4277 res_counter_uncharge(&batch
->memcg
->memsw
,
4278 batch
->memsw_nr_pages
* PAGE_SIZE
);
4279 memcg_oom_recover(batch
->memcg
);
4280 /* forget this pointer (for sanity check) */
4281 batch
->memcg
= NULL
;
4286 * called after __delete_from_swap_cache() and drop "page" account.
4287 * memcg information is recorded to swap_cgroup of "ent"
4290 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4292 struct mem_cgroup
*memcg
;
4293 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4295 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4296 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4298 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4301 * record memcg information, if swapout && memcg != NULL,
4302 * css_get() was called in uncharge().
4304 if (do_swap_account
&& swapout
&& memcg
)
4305 swap_cgroup_record(ent
, mem_cgroup_id(memcg
));
4309 #ifdef CONFIG_MEMCG_SWAP
4311 * called from swap_entry_free(). remove record in swap_cgroup and
4312 * uncharge "memsw" account.
4314 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4316 struct mem_cgroup
*memcg
;
4319 if (!do_swap_account
)
4322 id
= swap_cgroup_record(ent
, 0);
4324 memcg
= mem_cgroup_lookup(id
);
4327 * We uncharge this because swap is freed.
4328 * This memcg can be obsolete one. We avoid calling css_tryget
4330 if (!mem_cgroup_is_root(memcg
))
4331 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4332 mem_cgroup_swap_statistics(memcg
, false);
4333 css_put(&memcg
->css
);
4339 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4340 * @entry: swap entry to be moved
4341 * @from: mem_cgroup which the entry is moved from
4342 * @to: mem_cgroup which the entry is moved to
4344 * It succeeds only when the swap_cgroup's record for this entry is the same
4345 * as the mem_cgroup's id of @from.
4347 * Returns 0 on success, -EINVAL on failure.
4349 * The caller must have charged to @to, IOW, called res_counter_charge() about
4350 * both res and memsw, and called css_get().
4352 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4353 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4355 unsigned short old_id
, new_id
;
4357 old_id
= mem_cgroup_id(from
);
4358 new_id
= mem_cgroup_id(to
);
4360 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4361 mem_cgroup_swap_statistics(from
, false);
4362 mem_cgroup_swap_statistics(to
, true);
4364 * This function is only called from task migration context now.
4365 * It postpones res_counter and refcount handling till the end
4366 * of task migration(mem_cgroup_clear_mc()) for performance
4367 * improvement. But we cannot postpone css_get(to) because if
4368 * the process that has been moved to @to does swap-in, the
4369 * refcount of @to might be decreased to 0.
4371 * We are in attach() phase, so the cgroup is guaranteed to be
4372 * alive, so we can just call css_get().
4380 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4381 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4388 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4391 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4392 struct mem_cgroup
**memcgp
)
4394 struct mem_cgroup
*memcg
= NULL
;
4395 unsigned int nr_pages
= 1;
4396 struct page_cgroup
*pc
;
4397 enum charge_type ctype
;
4401 if (mem_cgroup_disabled())
4404 if (PageTransHuge(page
))
4405 nr_pages
<<= compound_order(page
);
4407 pc
= lookup_page_cgroup(page
);
4408 lock_page_cgroup(pc
);
4409 if (PageCgroupUsed(pc
)) {
4410 memcg
= pc
->mem_cgroup
;
4411 css_get(&memcg
->css
);
4413 * At migrating an anonymous page, its mapcount goes down
4414 * to 0 and uncharge() will be called. But, even if it's fully
4415 * unmapped, migration may fail and this page has to be
4416 * charged again. We set MIGRATION flag here and delay uncharge
4417 * until end_migration() is called
4419 * Corner Case Thinking
4421 * When the old page was mapped as Anon and it's unmap-and-freed
4422 * while migration was ongoing.
4423 * If unmap finds the old page, uncharge() of it will be delayed
4424 * until end_migration(). If unmap finds a new page, it's
4425 * uncharged when it make mapcount to be 1->0. If unmap code
4426 * finds swap_migration_entry, the new page will not be mapped
4427 * and end_migration() will find it(mapcount==0).
4430 * When the old page was mapped but migraion fails, the kernel
4431 * remaps it. A charge for it is kept by MIGRATION flag even
4432 * if mapcount goes down to 0. We can do remap successfully
4433 * without charging it again.
4436 * The "old" page is under lock_page() until the end of
4437 * migration, so, the old page itself will not be swapped-out.
4438 * If the new page is swapped out before end_migraton, our
4439 * hook to usual swap-out path will catch the event.
4442 SetPageCgroupMigration(pc
);
4444 unlock_page_cgroup(pc
);
4446 * If the page is not charged at this point,
4454 * We charge new page before it's used/mapped. So, even if unlock_page()
4455 * is called before end_migration, we can catch all events on this new
4456 * page. In the case new page is migrated but not remapped, new page's
4457 * mapcount will be finally 0 and we call uncharge in end_migration().
4460 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4462 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4464 * The page is committed to the memcg, but it's not actually
4465 * charged to the res_counter since we plan on replacing the
4466 * old one and only one page is going to be left afterwards.
4468 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4471 /* remove redundant charge if migration failed*/
4472 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4473 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4475 struct page
*used
, *unused
;
4476 struct page_cgroup
*pc
;
4482 if (!migration_ok
) {
4489 anon
= PageAnon(used
);
4490 __mem_cgroup_uncharge_common(unused
,
4491 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4492 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4494 css_put(&memcg
->css
);
4496 * We disallowed uncharge of pages under migration because mapcount
4497 * of the page goes down to zero, temporarly.
4498 * Clear the flag and check the page should be charged.
4500 pc
= lookup_page_cgroup(oldpage
);
4501 lock_page_cgroup(pc
);
4502 ClearPageCgroupMigration(pc
);
4503 unlock_page_cgroup(pc
);
4506 * If a page is a file cache, radix-tree replacement is very atomic
4507 * and we can skip this check. When it was an Anon page, its mapcount
4508 * goes down to 0. But because we added MIGRATION flage, it's not
4509 * uncharged yet. There are several case but page->mapcount check
4510 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4511 * check. (see prepare_charge() also)
4514 mem_cgroup_uncharge_page(used
);
4518 * At replace page cache, newpage is not under any memcg but it's on
4519 * LRU. So, this function doesn't touch res_counter but handles LRU
4520 * in correct way. Both pages are locked so we cannot race with uncharge.
4522 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4523 struct page
*newpage
)
4525 struct mem_cgroup
*memcg
= NULL
;
4526 struct page_cgroup
*pc
;
4527 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4529 if (mem_cgroup_disabled())
4532 pc
= lookup_page_cgroup(oldpage
);
4533 /* fix accounting on old pages */
4534 lock_page_cgroup(pc
);
4535 if (PageCgroupUsed(pc
)) {
4536 memcg
= pc
->mem_cgroup
;
4537 mem_cgroup_charge_statistics(memcg
, oldpage
, false, -1);
4538 ClearPageCgroupUsed(pc
);
4540 unlock_page_cgroup(pc
);
4543 * When called from shmem_replace_page(), in some cases the
4544 * oldpage has already been charged, and in some cases not.
4549 * Even if newpage->mapping was NULL before starting replacement,
4550 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4551 * LRU while we overwrite pc->mem_cgroup.
4553 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4556 #ifdef CONFIG_DEBUG_VM
4557 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4559 struct page_cgroup
*pc
;
4561 pc
= lookup_page_cgroup(page
);
4563 * Can be NULL while feeding pages into the page allocator for
4564 * the first time, i.e. during boot or memory hotplug;
4565 * or when mem_cgroup_disabled().
4567 if (likely(pc
) && PageCgroupUsed(pc
))
4572 bool mem_cgroup_bad_page_check(struct page
*page
)
4574 if (mem_cgroup_disabled())
4577 return lookup_page_cgroup_used(page
) != NULL
;
4580 void mem_cgroup_print_bad_page(struct page
*page
)
4582 struct page_cgroup
*pc
;
4584 pc
= lookup_page_cgroup_used(page
);
4586 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4587 pc
, pc
->flags
, pc
->mem_cgroup
);
4592 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4593 unsigned long long val
)
4596 u64 memswlimit
, memlimit
;
4598 int children
= mem_cgroup_count_children(memcg
);
4599 u64 curusage
, oldusage
;
4603 * For keeping hierarchical_reclaim simple, how long we should retry
4604 * is depends on callers. We set our retry-count to be function
4605 * of # of children which we should visit in this loop.
4607 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4609 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4612 while (retry_count
) {
4613 if (signal_pending(current
)) {
4618 * Rather than hide all in some function, I do this in
4619 * open coded manner. You see what this really does.
4620 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4622 mutex_lock(&set_limit_mutex
);
4623 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4624 if (memswlimit
< val
) {
4626 mutex_unlock(&set_limit_mutex
);
4630 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4634 ret
= res_counter_set_limit(&memcg
->res
, val
);
4636 if (memswlimit
== val
)
4637 memcg
->memsw_is_minimum
= true;
4639 memcg
->memsw_is_minimum
= false;
4641 mutex_unlock(&set_limit_mutex
);
4646 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4647 MEM_CGROUP_RECLAIM_SHRINK
);
4648 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4649 /* Usage is reduced ? */
4650 if (curusage
>= oldusage
)
4653 oldusage
= curusage
;
4655 if (!ret
&& enlarge
)
4656 memcg_oom_recover(memcg
);
4661 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4662 unsigned long long val
)
4665 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4666 int children
= mem_cgroup_count_children(memcg
);
4670 /* see mem_cgroup_resize_res_limit */
4671 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4672 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4673 while (retry_count
) {
4674 if (signal_pending(current
)) {
4679 * Rather than hide all in some function, I do this in
4680 * open coded manner. You see what this really does.
4681 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4683 mutex_lock(&set_limit_mutex
);
4684 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4685 if (memlimit
> val
) {
4687 mutex_unlock(&set_limit_mutex
);
4690 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4691 if (memswlimit
< val
)
4693 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4695 if (memlimit
== val
)
4696 memcg
->memsw_is_minimum
= true;
4698 memcg
->memsw_is_minimum
= false;
4700 mutex_unlock(&set_limit_mutex
);
4705 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4706 MEM_CGROUP_RECLAIM_NOSWAP
|
4707 MEM_CGROUP_RECLAIM_SHRINK
);
4708 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4709 /* Usage is reduced ? */
4710 if (curusage
>= oldusage
)
4713 oldusage
= curusage
;
4715 if (!ret
&& enlarge
)
4716 memcg_oom_recover(memcg
);
4720 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
4722 unsigned long *total_scanned
)
4724 unsigned long nr_reclaimed
= 0;
4725 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
4726 unsigned long reclaimed
;
4728 struct mem_cgroup_tree_per_zone
*mctz
;
4729 unsigned long long excess
;
4730 unsigned long nr_scanned
;
4735 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
4737 * This loop can run a while, specially if mem_cgroup's continuously
4738 * keep exceeding their soft limit and putting the system under
4745 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
4750 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
4751 gfp_mask
, &nr_scanned
);
4752 nr_reclaimed
+= reclaimed
;
4753 *total_scanned
+= nr_scanned
;
4754 spin_lock(&mctz
->lock
);
4757 * If we failed to reclaim anything from this memory cgroup
4758 * it is time to move on to the next cgroup
4764 * Loop until we find yet another one.
4766 * By the time we get the soft_limit lock
4767 * again, someone might have aded the
4768 * group back on the RB tree. Iterate to
4769 * make sure we get a different mem.
4770 * mem_cgroup_largest_soft_limit_node returns
4771 * NULL if no other cgroup is present on
4775 __mem_cgroup_largest_soft_limit_node(mctz
);
4777 css_put(&next_mz
->memcg
->css
);
4778 else /* next_mz == NULL or other memcg */
4782 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
4783 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
4785 * One school of thought says that we should not add
4786 * back the node to the tree if reclaim returns 0.
4787 * But our reclaim could return 0, simply because due
4788 * to priority we are exposing a smaller subset of
4789 * memory to reclaim from. Consider this as a longer
4792 /* If excess == 0, no tree ops */
4793 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
4794 spin_unlock(&mctz
->lock
);
4795 css_put(&mz
->memcg
->css
);
4798 * Could not reclaim anything and there are no more
4799 * mem cgroups to try or we seem to be looping without
4800 * reclaiming anything.
4802 if (!nr_reclaimed
&&
4804 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
4806 } while (!nr_reclaimed
);
4808 css_put(&next_mz
->memcg
->css
);
4809 return nr_reclaimed
;
4813 * mem_cgroup_force_empty_list - clears LRU of a group
4814 * @memcg: group to clear
4817 * @lru: lru to to clear
4819 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4820 * reclaim the pages page themselves - pages are moved to the parent (or root)
4823 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4824 int node
, int zid
, enum lru_list lru
)
4826 struct lruvec
*lruvec
;
4827 unsigned long flags
;
4828 struct list_head
*list
;
4832 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4833 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4834 list
= &lruvec
->lists
[lru
];
4838 struct page_cgroup
*pc
;
4841 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4842 if (list_empty(list
)) {
4843 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4846 page
= list_entry(list
->prev
, struct page
, lru
);
4848 list_move(&page
->lru
, list
);
4850 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4853 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4855 pc
= lookup_page_cgroup(page
);
4857 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4858 /* found lock contention or "pc" is obsolete. */
4863 } while (!list_empty(list
));
4867 * make mem_cgroup's charge to be 0 if there is no task by moving
4868 * all the charges and pages to the parent.
4869 * This enables deleting this mem_cgroup.
4871 * Caller is responsible for holding css reference on the memcg.
4873 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4879 /* This is for making all *used* pages to be on LRU. */
4880 lru_add_drain_all();
4881 drain_all_stock_sync(memcg
);
4882 mem_cgroup_start_move(memcg
);
4883 for_each_node_state(node
, N_MEMORY
) {
4884 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4887 mem_cgroup_force_empty_list(memcg
,
4892 mem_cgroup_end_move(memcg
);
4893 memcg_oom_recover(memcg
);
4897 * Kernel memory may not necessarily be trackable to a specific
4898 * process. So they are not migrated, and therefore we can't
4899 * expect their value to drop to 0 here.
4900 * Having res filled up with kmem only is enough.
4902 * This is a safety check because mem_cgroup_force_empty_list
4903 * could have raced with mem_cgroup_replace_page_cache callers
4904 * so the lru seemed empty but the page could have been added
4905 * right after the check. RES_USAGE should be safe as we always
4906 * charge before adding to the LRU.
4908 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
4909 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
4910 } while (usage
> 0);
4913 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
4915 lockdep_assert_held(&memcg_create_mutex
);
4917 * The lock does not prevent addition or deletion to the list
4918 * of children, but it prevents a new child from being
4919 * initialized based on this parent in css_online(), so it's
4920 * enough to decide whether hierarchically inherited
4921 * attributes can still be changed or not.
4923 return memcg
->use_hierarchy
&&
4924 !list_empty(&memcg
->css
.cgroup
->children
);
4928 * Reclaims as many pages from the given memcg as possible and moves
4929 * the rest to the parent.
4931 * Caller is responsible for holding css reference for memcg.
4933 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
4935 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
4936 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
4938 /* returns EBUSY if there is a task or if we come here twice. */
4939 if (cgroup_has_tasks(cgrp
) || !list_empty(&cgrp
->children
))
4942 /* we call try-to-free pages for make this cgroup empty */
4943 lru_add_drain_all();
4944 /* try to free all pages in this cgroup */
4945 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
4948 if (signal_pending(current
))
4951 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
4955 /* maybe some writeback is necessary */
4956 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
4961 mem_cgroup_reparent_charges(memcg
);
4966 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state
*css
,
4969 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4971 if (mem_cgroup_is_root(memcg
))
4973 return mem_cgroup_force_empty(memcg
);
4976 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
4979 return mem_cgroup_from_css(css
)->use_hierarchy
;
4982 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
4983 struct cftype
*cft
, u64 val
)
4986 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4987 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
4989 mutex_lock(&memcg_create_mutex
);
4991 if (memcg
->use_hierarchy
== val
)
4995 * If parent's use_hierarchy is set, we can't make any modifications
4996 * in the child subtrees. If it is unset, then the change can
4997 * occur, provided the current cgroup has no children.
4999 * For the root cgroup, parent_mem is NULL, we allow value to be
5000 * set if there are no children.
5002 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
5003 (val
== 1 || val
== 0)) {
5004 if (list_empty(&memcg
->css
.cgroup
->children
))
5005 memcg
->use_hierarchy
= val
;
5012 mutex_unlock(&memcg_create_mutex
);
5018 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
5019 enum mem_cgroup_stat_index idx
)
5021 struct mem_cgroup
*iter
;
5024 /* Per-cpu values can be negative, use a signed accumulator */
5025 for_each_mem_cgroup_tree(iter
, memcg
)
5026 val
+= mem_cgroup_read_stat(iter
, idx
);
5028 if (val
< 0) /* race ? */
5033 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
5037 if (!mem_cgroup_is_root(memcg
)) {
5039 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
5041 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
5045 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
5046 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
5048 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
5049 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
5052 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
5054 return val
<< PAGE_SHIFT
;
5057 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
5060 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5065 type
= MEMFILE_TYPE(cft
->private);
5066 name
= MEMFILE_ATTR(cft
->private);
5070 if (name
== RES_USAGE
)
5071 val
= mem_cgroup_usage(memcg
, false);
5073 val
= res_counter_read_u64(&memcg
->res
, name
);
5076 if (name
== RES_USAGE
)
5077 val
= mem_cgroup_usage(memcg
, true);
5079 val
= res_counter_read_u64(&memcg
->memsw
, name
);
5082 val
= res_counter_read_u64(&memcg
->kmem
, name
);
5091 #ifdef CONFIG_MEMCG_KMEM
5092 /* should be called with activate_kmem_mutex held */
5093 static int __memcg_activate_kmem(struct mem_cgroup
*memcg
,
5094 unsigned long long limit
)
5099 if (memcg_kmem_is_active(memcg
))
5103 * We are going to allocate memory for data shared by all memory
5104 * cgroups so let's stop accounting here.
5106 memcg_stop_kmem_account();
5109 * For simplicity, we won't allow this to be disabled. It also can't
5110 * be changed if the cgroup has children already, or if tasks had
5113 * If tasks join before we set the limit, a person looking at
5114 * kmem.usage_in_bytes will have no way to determine when it took
5115 * place, which makes the value quite meaningless.
5117 * After it first became limited, changes in the value of the limit are
5118 * of course permitted.
5120 mutex_lock(&memcg_create_mutex
);
5121 if (cgroup_has_tasks(memcg
->css
.cgroup
) || memcg_has_children(memcg
))
5123 mutex_unlock(&memcg_create_mutex
);
5127 memcg_id
= ida_simple_get(&kmem_limited_groups
,
5128 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
5135 * Make sure we have enough space for this cgroup in each root cache's
5138 err
= memcg_update_all_caches(memcg_id
+ 1);
5142 memcg
->kmemcg_id
= memcg_id
;
5143 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
5144 mutex_init(&memcg
->slab_caches_mutex
);
5147 * We couldn't have accounted to this cgroup, because it hasn't got the
5148 * active bit set yet, so this should succeed.
5150 err
= res_counter_set_limit(&memcg
->kmem
, limit
);
5153 static_key_slow_inc(&memcg_kmem_enabled_key
);
5155 * Setting the active bit after enabling static branching will
5156 * guarantee no one starts accounting before all call sites are
5159 memcg_kmem_set_active(memcg
);
5161 memcg_resume_kmem_account();
5165 ida_simple_remove(&kmem_limited_groups
, memcg_id
);
5169 static int memcg_activate_kmem(struct mem_cgroup
*memcg
,
5170 unsigned long long limit
)
5174 mutex_lock(&activate_kmem_mutex
);
5175 ret
= __memcg_activate_kmem(memcg
, limit
);
5176 mutex_unlock(&activate_kmem_mutex
);
5180 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
5181 unsigned long long val
)
5185 if (!memcg_kmem_is_active(memcg
))
5186 ret
= memcg_activate_kmem(memcg
, val
);
5188 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5192 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5195 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5200 mutex_lock(&activate_kmem_mutex
);
5202 * If the parent cgroup is not kmem-active now, it cannot be activated
5203 * after this point, because it has at least one child already.
5205 if (memcg_kmem_is_active(parent
))
5206 ret
= __memcg_activate_kmem(memcg
, RES_COUNTER_MAX
);
5207 mutex_unlock(&activate_kmem_mutex
);
5211 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
5212 unsigned long long val
)
5216 #endif /* CONFIG_MEMCG_KMEM */
5219 * The user of this function is...
5222 static int mem_cgroup_write(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
5225 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5228 unsigned long long val
;
5231 type
= MEMFILE_TYPE(cft
->private);
5232 name
= MEMFILE_ATTR(cft
->private);
5236 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5240 /* This function does all necessary parse...reuse it */
5241 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5245 ret
= mem_cgroup_resize_limit(memcg
, val
);
5246 else if (type
== _MEMSWAP
)
5247 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5248 else if (type
== _KMEM
)
5249 ret
= memcg_update_kmem_limit(memcg
, val
);
5253 case RES_SOFT_LIMIT
:
5254 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5258 * For memsw, soft limits are hard to implement in terms
5259 * of semantics, for now, we support soft limits for
5260 * control without swap
5263 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5268 ret
= -EINVAL
; /* should be BUG() ? */
5274 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5275 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5277 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5279 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5280 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5281 if (!memcg
->use_hierarchy
)
5284 while (css_parent(&memcg
->css
)) {
5285 memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5286 if (!memcg
->use_hierarchy
)
5288 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5289 min_limit
= min(min_limit
, tmp
);
5290 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5291 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5294 *mem_limit
= min_limit
;
5295 *memsw_limit
= min_memsw_limit
;
5298 static int mem_cgroup_reset(struct cgroup_subsys_state
*css
, unsigned int event
)
5300 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5304 type
= MEMFILE_TYPE(event
);
5305 name
= MEMFILE_ATTR(event
);
5310 res_counter_reset_max(&memcg
->res
);
5311 else if (type
== _MEMSWAP
)
5312 res_counter_reset_max(&memcg
->memsw
);
5313 else if (type
== _KMEM
)
5314 res_counter_reset_max(&memcg
->kmem
);
5320 res_counter_reset_failcnt(&memcg
->res
);
5321 else if (type
== _MEMSWAP
)
5322 res_counter_reset_failcnt(&memcg
->memsw
);
5323 else if (type
== _KMEM
)
5324 res_counter_reset_failcnt(&memcg
->kmem
);
5333 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
5336 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
5340 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5341 struct cftype
*cft
, u64 val
)
5343 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5345 if (val
>= (1 << NR_MOVE_TYPE
))
5349 * No kind of locking is needed in here, because ->can_attach() will
5350 * check this value once in the beginning of the process, and then carry
5351 * on with stale data. This means that changes to this value will only
5352 * affect task migrations starting after the change.
5354 memcg
->move_charge_at_immigrate
= val
;
5358 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5359 struct cftype
*cft
, u64 val
)
5366 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
5370 unsigned int lru_mask
;
5373 static const struct numa_stat stats
[] = {
5374 { "total", LRU_ALL
},
5375 { "file", LRU_ALL_FILE
},
5376 { "anon", LRU_ALL_ANON
},
5377 { "unevictable", BIT(LRU_UNEVICTABLE
) },
5379 const struct numa_stat
*stat
;
5382 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5384 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5385 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
5386 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
5387 for_each_node_state(nid
, N_MEMORY
) {
5388 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5390 seq_printf(m
, " N%d=%lu", nid
, nr
);
5395 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5396 struct mem_cgroup
*iter
;
5399 for_each_mem_cgroup_tree(iter
, memcg
)
5400 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
5401 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
5402 for_each_node_state(nid
, N_MEMORY
) {
5404 for_each_mem_cgroup_tree(iter
, memcg
)
5405 nr
+= mem_cgroup_node_nr_lru_pages(
5406 iter
, nid
, stat
->lru_mask
);
5407 seq_printf(m
, " N%d=%lu", nid
, nr
);
5414 #endif /* CONFIG_NUMA */
5416 static inline void mem_cgroup_lru_names_not_uptodate(void)
5418 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5421 static int memcg_stat_show(struct seq_file
*m
, void *v
)
5423 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5424 struct mem_cgroup
*mi
;
5427 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5428 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5430 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5431 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5434 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5435 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5436 mem_cgroup_read_events(memcg
, i
));
5438 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5439 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5440 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5442 /* Hierarchical information */
5444 unsigned long long limit
, memsw_limit
;
5445 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5446 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5447 if (do_swap_account
)
5448 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5452 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5455 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5457 for_each_mem_cgroup_tree(mi
, memcg
)
5458 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5459 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5462 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5463 unsigned long long val
= 0;
5465 for_each_mem_cgroup_tree(mi
, memcg
)
5466 val
+= mem_cgroup_read_events(mi
, i
);
5467 seq_printf(m
, "total_%s %llu\n",
5468 mem_cgroup_events_names
[i
], val
);
5471 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5472 unsigned long long val
= 0;
5474 for_each_mem_cgroup_tree(mi
, memcg
)
5475 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5476 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5479 #ifdef CONFIG_DEBUG_VM
5482 struct mem_cgroup_per_zone
*mz
;
5483 struct zone_reclaim_stat
*rstat
;
5484 unsigned long recent_rotated
[2] = {0, 0};
5485 unsigned long recent_scanned
[2] = {0, 0};
5487 for_each_online_node(nid
)
5488 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5489 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5490 rstat
= &mz
->lruvec
.reclaim_stat
;
5492 recent_rotated
[0] += rstat
->recent_rotated
[0];
5493 recent_rotated
[1] += rstat
->recent_rotated
[1];
5494 recent_scanned
[0] += rstat
->recent_scanned
[0];
5495 recent_scanned
[1] += rstat
->recent_scanned
[1];
5497 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5498 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5499 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5500 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5507 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
5510 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5512 return mem_cgroup_swappiness(memcg
);
5515 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
5516 struct cftype
*cft
, u64 val
)
5518 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5519 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5521 if (val
> 100 || !parent
)
5524 mutex_lock(&memcg_create_mutex
);
5526 /* If under hierarchy, only empty-root can set this value */
5527 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5528 mutex_unlock(&memcg_create_mutex
);
5532 memcg
->swappiness
= val
;
5534 mutex_unlock(&memcg_create_mutex
);
5539 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5541 struct mem_cgroup_threshold_ary
*t
;
5547 t
= rcu_dereference(memcg
->thresholds
.primary
);
5549 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5554 usage
= mem_cgroup_usage(memcg
, swap
);
5557 * current_threshold points to threshold just below or equal to usage.
5558 * If it's not true, a threshold was crossed after last
5559 * call of __mem_cgroup_threshold().
5561 i
= t
->current_threshold
;
5564 * Iterate backward over array of thresholds starting from
5565 * current_threshold and check if a threshold is crossed.
5566 * If none of thresholds below usage is crossed, we read
5567 * only one element of the array here.
5569 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5570 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5572 /* i = current_threshold + 1 */
5576 * Iterate forward over array of thresholds starting from
5577 * current_threshold+1 and check if a threshold is crossed.
5578 * If none of thresholds above usage is crossed, we read
5579 * only one element of the array here.
5581 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5582 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5584 /* Update current_threshold */
5585 t
->current_threshold
= i
- 1;
5590 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5593 __mem_cgroup_threshold(memcg
, false);
5594 if (do_swap_account
)
5595 __mem_cgroup_threshold(memcg
, true);
5597 memcg
= parent_mem_cgroup(memcg
);
5601 static int compare_thresholds(const void *a
, const void *b
)
5603 const struct mem_cgroup_threshold
*_a
= a
;
5604 const struct mem_cgroup_threshold
*_b
= b
;
5606 if (_a
->threshold
> _b
->threshold
)
5609 if (_a
->threshold
< _b
->threshold
)
5615 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5617 struct mem_cgroup_eventfd_list
*ev
;
5619 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5620 eventfd_signal(ev
->eventfd
, 1);
5624 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5626 struct mem_cgroup
*iter
;
5628 for_each_mem_cgroup_tree(iter
, memcg
)
5629 mem_cgroup_oom_notify_cb(iter
);
5632 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5633 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
5635 struct mem_cgroup_thresholds
*thresholds
;
5636 struct mem_cgroup_threshold_ary
*new;
5637 u64 threshold
, usage
;
5640 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5644 mutex_lock(&memcg
->thresholds_lock
);
5647 thresholds
= &memcg
->thresholds
;
5648 else if (type
== _MEMSWAP
)
5649 thresholds
= &memcg
->memsw_thresholds
;
5653 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5655 /* Check if a threshold crossed before adding a new one */
5656 if (thresholds
->primary
)
5657 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5659 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5661 /* Allocate memory for new array of thresholds */
5662 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5670 /* Copy thresholds (if any) to new array */
5671 if (thresholds
->primary
) {
5672 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5673 sizeof(struct mem_cgroup_threshold
));
5676 /* Add new threshold */
5677 new->entries
[size
- 1].eventfd
= eventfd
;
5678 new->entries
[size
- 1].threshold
= threshold
;
5680 /* Sort thresholds. Registering of new threshold isn't time-critical */
5681 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5682 compare_thresholds
, NULL
);
5684 /* Find current threshold */
5685 new->current_threshold
= -1;
5686 for (i
= 0; i
< size
; i
++) {
5687 if (new->entries
[i
].threshold
<= usage
) {
5689 * new->current_threshold will not be used until
5690 * rcu_assign_pointer(), so it's safe to increment
5693 ++new->current_threshold
;
5698 /* Free old spare buffer and save old primary buffer as spare */
5699 kfree(thresholds
->spare
);
5700 thresholds
->spare
= thresholds
->primary
;
5702 rcu_assign_pointer(thresholds
->primary
, new);
5704 /* To be sure that nobody uses thresholds */
5708 mutex_unlock(&memcg
->thresholds_lock
);
5713 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5714 struct eventfd_ctx
*eventfd
, const char *args
)
5716 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
5719 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5720 struct eventfd_ctx
*eventfd
, const char *args
)
5722 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
5725 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5726 struct eventfd_ctx
*eventfd
, enum res_type type
)
5728 struct mem_cgroup_thresholds
*thresholds
;
5729 struct mem_cgroup_threshold_ary
*new;
5733 mutex_lock(&memcg
->thresholds_lock
);
5735 thresholds
= &memcg
->thresholds
;
5736 else if (type
== _MEMSWAP
)
5737 thresholds
= &memcg
->memsw_thresholds
;
5741 if (!thresholds
->primary
)
5744 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5746 /* Check if a threshold crossed before removing */
5747 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5749 /* Calculate new number of threshold */
5751 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5752 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5756 new = thresholds
->spare
;
5758 /* Set thresholds array to NULL if we don't have thresholds */
5767 /* Copy thresholds and find current threshold */
5768 new->current_threshold
= -1;
5769 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5770 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5773 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5774 if (new->entries
[j
].threshold
<= usage
) {
5776 * new->current_threshold will not be used
5777 * until rcu_assign_pointer(), so it's safe to increment
5780 ++new->current_threshold
;
5786 /* Swap primary and spare array */
5787 thresholds
->spare
= thresholds
->primary
;
5788 /* If all events are unregistered, free the spare array */
5790 kfree(thresholds
->spare
);
5791 thresholds
->spare
= NULL
;
5794 rcu_assign_pointer(thresholds
->primary
, new);
5796 /* To be sure that nobody uses thresholds */
5799 mutex_unlock(&memcg
->thresholds_lock
);
5802 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5803 struct eventfd_ctx
*eventfd
)
5805 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
5808 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5809 struct eventfd_ctx
*eventfd
)
5811 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
5814 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
5815 struct eventfd_ctx
*eventfd
, const char *args
)
5817 struct mem_cgroup_eventfd_list
*event
;
5819 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5823 spin_lock(&memcg_oom_lock
);
5825 event
->eventfd
= eventfd
;
5826 list_add(&event
->list
, &memcg
->oom_notify
);
5828 /* already in OOM ? */
5829 if (atomic_read(&memcg
->under_oom
))
5830 eventfd_signal(eventfd
, 1);
5831 spin_unlock(&memcg_oom_lock
);
5836 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
5837 struct eventfd_ctx
*eventfd
)
5839 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5841 spin_lock(&memcg_oom_lock
);
5843 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5844 if (ev
->eventfd
== eventfd
) {
5845 list_del(&ev
->list
);
5850 spin_unlock(&memcg_oom_lock
);
5853 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
5855 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
5857 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
5858 seq_printf(sf
, "under_oom %d\n", (bool)atomic_read(&memcg
->under_oom
));
5862 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
5863 struct cftype
*cft
, u64 val
)
5865 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5866 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5868 /* cannot set to root cgroup and only 0 and 1 are allowed */
5869 if (!parent
|| !((val
== 0) || (val
== 1)))
5872 mutex_lock(&memcg_create_mutex
);
5873 /* oom-kill-disable is a flag for subhierarchy. */
5874 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5875 mutex_unlock(&memcg_create_mutex
);
5878 memcg
->oom_kill_disable
= val
;
5880 memcg_oom_recover(memcg
);
5881 mutex_unlock(&memcg_create_mutex
);
5885 #ifdef CONFIG_MEMCG_KMEM
5886 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5890 memcg
->kmemcg_id
= -1;
5891 ret
= memcg_propagate_kmem(memcg
);
5895 return mem_cgroup_sockets_init(memcg
, ss
);
5898 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5900 mem_cgroup_sockets_destroy(memcg
);
5903 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5905 if (!memcg_kmem_is_active(memcg
))
5909 * kmem charges can outlive the cgroup. In the case of slab
5910 * pages, for instance, a page contain objects from various
5911 * processes. As we prevent from taking a reference for every
5912 * such allocation we have to be careful when doing uncharge
5913 * (see memcg_uncharge_kmem) and here during offlining.
5915 * The idea is that that only the _last_ uncharge which sees
5916 * the dead memcg will drop the last reference. An additional
5917 * reference is taken here before the group is marked dead
5918 * which is then paired with css_put during uncharge resp. here.
5920 * Although this might sound strange as this path is called from
5921 * css_offline() when the referencemight have dropped down to 0
5922 * and shouldn't be incremented anymore (css_tryget would fail)
5923 * we do not have other options because of the kmem allocations
5926 css_get(&memcg
->css
);
5928 memcg_kmem_mark_dead(memcg
);
5930 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5933 if (memcg_kmem_test_and_clear_dead(memcg
))
5934 css_put(&memcg
->css
);
5937 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5942 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5946 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5952 * DO NOT USE IN NEW FILES.
5954 * "cgroup.event_control" implementation.
5956 * This is way over-engineered. It tries to support fully configurable
5957 * events for each user. Such level of flexibility is completely
5958 * unnecessary especially in the light of the planned unified hierarchy.
5960 * Please deprecate this and replace with something simpler if at all
5965 * Unregister event and free resources.
5967 * Gets called from workqueue.
5969 static void memcg_event_remove(struct work_struct
*work
)
5971 struct mem_cgroup_event
*event
=
5972 container_of(work
, struct mem_cgroup_event
, remove
);
5973 struct mem_cgroup
*memcg
= event
->memcg
;
5975 remove_wait_queue(event
->wqh
, &event
->wait
);
5977 event
->unregister_event(memcg
, event
->eventfd
);
5979 /* Notify userspace the event is going away. */
5980 eventfd_signal(event
->eventfd
, 1);
5982 eventfd_ctx_put(event
->eventfd
);
5984 css_put(&memcg
->css
);
5988 * Gets called on POLLHUP on eventfd when user closes it.
5990 * Called with wqh->lock held and interrupts disabled.
5992 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
5993 int sync
, void *key
)
5995 struct mem_cgroup_event
*event
=
5996 container_of(wait
, struct mem_cgroup_event
, wait
);
5997 struct mem_cgroup
*memcg
= event
->memcg
;
5998 unsigned long flags
= (unsigned long)key
;
6000 if (flags
& POLLHUP
) {
6002 * If the event has been detached at cgroup removal, we
6003 * can simply return knowing the other side will cleanup
6006 * We can't race against event freeing since the other
6007 * side will require wqh->lock via remove_wait_queue(),
6010 spin_lock(&memcg
->event_list_lock
);
6011 if (!list_empty(&event
->list
)) {
6012 list_del_init(&event
->list
);
6014 * We are in atomic context, but cgroup_event_remove()
6015 * may sleep, so we have to call it in workqueue.
6017 schedule_work(&event
->remove
);
6019 spin_unlock(&memcg
->event_list_lock
);
6025 static void memcg_event_ptable_queue_proc(struct file
*file
,
6026 wait_queue_head_t
*wqh
, poll_table
*pt
)
6028 struct mem_cgroup_event
*event
=
6029 container_of(pt
, struct mem_cgroup_event
, pt
);
6032 add_wait_queue(wqh
, &event
->wait
);
6036 * DO NOT USE IN NEW FILES.
6038 * Parse input and register new cgroup event handler.
6040 * Input must be in format '<event_fd> <control_fd> <args>'.
6041 * Interpretation of args is defined by control file implementation.
6043 static int memcg_write_event_control(struct cgroup_subsys_state
*css
,
6044 struct cftype
*cft
, char *buffer
)
6046 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6047 struct mem_cgroup_event
*event
;
6048 struct cgroup_subsys_state
*cfile_css
;
6049 unsigned int efd
, cfd
;
6056 efd
= simple_strtoul(buffer
, &endp
, 10);
6061 cfd
= simple_strtoul(buffer
, &endp
, 10);
6062 if ((*endp
!= ' ') && (*endp
!= '\0'))
6066 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6070 event
->memcg
= memcg
;
6071 INIT_LIST_HEAD(&event
->list
);
6072 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
6073 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
6074 INIT_WORK(&event
->remove
, memcg_event_remove
);
6082 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
6083 if (IS_ERR(event
->eventfd
)) {
6084 ret
= PTR_ERR(event
->eventfd
);
6091 goto out_put_eventfd
;
6094 /* the process need read permission on control file */
6095 /* AV: shouldn't we check that it's been opened for read instead? */
6096 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
6101 * Determine the event callbacks and set them in @event. This used
6102 * to be done via struct cftype but cgroup core no longer knows
6103 * about these events. The following is crude but the whole thing
6104 * is for compatibility anyway.
6106 * DO NOT ADD NEW FILES.
6108 name
= cfile
.file
->f_dentry
->d_name
.name
;
6110 if (!strcmp(name
, "memory.usage_in_bytes")) {
6111 event
->register_event
= mem_cgroup_usage_register_event
;
6112 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
6113 } else if (!strcmp(name
, "memory.oom_control")) {
6114 event
->register_event
= mem_cgroup_oom_register_event
;
6115 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
6116 } else if (!strcmp(name
, "memory.pressure_level")) {
6117 event
->register_event
= vmpressure_register_event
;
6118 event
->unregister_event
= vmpressure_unregister_event
;
6119 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
6120 event
->register_event
= memsw_cgroup_usage_register_event
;
6121 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
6128 * Verify @cfile should belong to @css. Also, remaining events are
6129 * automatically removed on cgroup destruction but the removal is
6130 * asynchronous, so take an extra ref on @css.
6132 cfile_css
= css_tryget_from_dir(cfile
.file
->f_dentry
->d_parent
,
6133 &memory_cgrp_subsys
);
6135 if (IS_ERR(cfile_css
))
6137 if (cfile_css
!= css
) {
6142 ret
= event
->register_event(memcg
, event
->eventfd
, buffer
);
6146 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
6148 spin_lock(&memcg
->event_list_lock
);
6149 list_add(&event
->list
, &memcg
->event_list
);
6150 spin_unlock(&memcg
->event_list_lock
);
6162 eventfd_ctx_put(event
->eventfd
);
6171 static struct cftype mem_cgroup_files
[] = {
6173 .name
= "usage_in_bytes",
6174 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
6175 .read_u64
= mem_cgroup_read_u64
,
6178 .name
= "max_usage_in_bytes",
6179 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
6180 .trigger
= mem_cgroup_reset
,
6181 .read_u64
= mem_cgroup_read_u64
,
6184 .name
= "limit_in_bytes",
6185 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
6186 .write_string
= mem_cgroup_write
,
6187 .read_u64
= mem_cgroup_read_u64
,
6190 .name
= "soft_limit_in_bytes",
6191 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
6192 .write_string
= mem_cgroup_write
,
6193 .read_u64
= mem_cgroup_read_u64
,
6197 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
6198 .trigger
= mem_cgroup_reset
,
6199 .read_u64
= mem_cgroup_read_u64
,
6203 .seq_show
= memcg_stat_show
,
6206 .name
= "force_empty",
6207 .trigger
= mem_cgroup_force_empty_write
,
6210 .name
= "use_hierarchy",
6211 .flags
= CFTYPE_INSANE
,
6212 .write_u64
= mem_cgroup_hierarchy_write
,
6213 .read_u64
= mem_cgroup_hierarchy_read
,
6216 .name
= "cgroup.event_control", /* XXX: for compat */
6217 .write_string
= memcg_write_event_control
,
6218 .flags
= CFTYPE_NO_PREFIX
,
6222 .name
= "swappiness",
6223 .read_u64
= mem_cgroup_swappiness_read
,
6224 .write_u64
= mem_cgroup_swappiness_write
,
6227 .name
= "move_charge_at_immigrate",
6228 .read_u64
= mem_cgroup_move_charge_read
,
6229 .write_u64
= mem_cgroup_move_charge_write
,
6232 .name
= "oom_control",
6233 .seq_show
= mem_cgroup_oom_control_read
,
6234 .write_u64
= mem_cgroup_oom_control_write
,
6235 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
6238 .name
= "pressure_level",
6242 .name
= "numa_stat",
6243 .seq_show
= memcg_numa_stat_show
,
6246 #ifdef CONFIG_MEMCG_KMEM
6248 .name
= "kmem.limit_in_bytes",
6249 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
6250 .write_string
= mem_cgroup_write
,
6251 .read_u64
= mem_cgroup_read_u64
,
6254 .name
= "kmem.usage_in_bytes",
6255 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
6256 .read_u64
= mem_cgroup_read_u64
,
6259 .name
= "kmem.failcnt",
6260 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
6261 .trigger
= mem_cgroup_reset
,
6262 .read_u64
= mem_cgroup_read_u64
,
6265 .name
= "kmem.max_usage_in_bytes",
6266 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
6267 .trigger
= mem_cgroup_reset
,
6268 .read_u64
= mem_cgroup_read_u64
,
6270 #ifdef CONFIG_SLABINFO
6272 .name
= "kmem.slabinfo",
6273 .seq_show
= mem_cgroup_slabinfo_read
,
6277 { }, /* terminate */
6280 #ifdef CONFIG_MEMCG_SWAP
6281 static struct cftype memsw_cgroup_files
[] = {
6283 .name
= "memsw.usage_in_bytes",
6284 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6285 .read_u64
= mem_cgroup_read_u64
,
6288 .name
= "memsw.max_usage_in_bytes",
6289 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6290 .trigger
= mem_cgroup_reset
,
6291 .read_u64
= mem_cgroup_read_u64
,
6294 .name
= "memsw.limit_in_bytes",
6295 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6296 .write_string
= mem_cgroup_write
,
6297 .read_u64
= mem_cgroup_read_u64
,
6300 .name
= "memsw.failcnt",
6301 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6302 .trigger
= mem_cgroup_reset
,
6303 .read_u64
= mem_cgroup_read_u64
,
6305 { }, /* terminate */
6308 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6310 struct mem_cgroup_per_node
*pn
;
6311 struct mem_cgroup_per_zone
*mz
;
6312 int zone
, tmp
= node
;
6314 * This routine is called against possible nodes.
6315 * But it's BUG to call kmalloc() against offline node.
6317 * TODO: this routine can waste much memory for nodes which will
6318 * never be onlined. It's better to use memory hotplug callback
6321 if (!node_state(node
, N_NORMAL_MEMORY
))
6323 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
6327 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6328 mz
= &pn
->zoneinfo
[zone
];
6329 lruvec_init(&mz
->lruvec
);
6330 mz
->usage_in_excess
= 0;
6331 mz
->on_tree
= false;
6334 memcg
->nodeinfo
[node
] = pn
;
6338 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6340 kfree(memcg
->nodeinfo
[node
]);
6343 static struct mem_cgroup
*mem_cgroup_alloc(void)
6345 struct mem_cgroup
*memcg
;
6348 size
= sizeof(struct mem_cgroup
);
6349 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
6351 memcg
= kzalloc(size
, GFP_KERNEL
);
6355 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
6358 spin_lock_init(&memcg
->pcp_counter_lock
);
6367 * At destroying mem_cgroup, references from swap_cgroup can remain.
6368 * (scanning all at force_empty is too costly...)
6370 * Instead of clearing all references at force_empty, we remember
6371 * the number of reference from swap_cgroup and free mem_cgroup when
6372 * it goes down to 0.
6374 * Removal of cgroup itself succeeds regardless of refs from swap.
6377 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
6381 mem_cgroup_remove_from_trees(memcg
);
6384 free_mem_cgroup_per_zone_info(memcg
, node
);
6386 free_percpu(memcg
->stat
);
6389 * We need to make sure that (at least for now), the jump label
6390 * destruction code runs outside of the cgroup lock. This is because
6391 * get_online_cpus(), which is called from the static_branch update,
6392 * can't be called inside the cgroup_lock. cpusets are the ones
6393 * enforcing this dependency, so if they ever change, we might as well.
6395 * schedule_work() will guarantee this happens. Be careful if you need
6396 * to move this code around, and make sure it is outside
6399 disarm_static_keys(memcg
);
6404 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6406 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6408 if (!memcg
->res
.parent
)
6410 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6412 EXPORT_SYMBOL(parent_mem_cgroup
);
6414 static void __init
mem_cgroup_soft_limit_tree_init(void)
6416 struct mem_cgroup_tree_per_node
*rtpn
;
6417 struct mem_cgroup_tree_per_zone
*rtpz
;
6418 int tmp
, node
, zone
;
6420 for_each_node(node
) {
6422 if (!node_state(node
, N_NORMAL_MEMORY
))
6424 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
6427 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6429 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6430 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
6431 rtpz
->rb_root
= RB_ROOT
;
6432 spin_lock_init(&rtpz
->lock
);
6437 static struct cgroup_subsys_state
* __ref
6438 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
6440 struct mem_cgroup
*memcg
;
6441 long error
= -ENOMEM
;
6444 memcg
= mem_cgroup_alloc();
6446 return ERR_PTR(error
);
6449 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6453 if (parent_css
== NULL
) {
6454 root_mem_cgroup
= memcg
;
6455 res_counter_init(&memcg
->res
, NULL
);
6456 res_counter_init(&memcg
->memsw
, NULL
);
6457 res_counter_init(&memcg
->kmem
, NULL
);
6460 memcg
->last_scanned_node
= MAX_NUMNODES
;
6461 INIT_LIST_HEAD(&memcg
->oom_notify
);
6462 memcg
->move_charge_at_immigrate
= 0;
6463 mutex_init(&memcg
->thresholds_lock
);
6464 spin_lock_init(&memcg
->move_lock
);
6465 vmpressure_init(&memcg
->vmpressure
);
6466 INIT_LIST_HEAD(&memcg
->event_list
);
6467 spin_lock_init(&memcg
->event_list_lock
);
6472 __mem_cgroup_free(memcg
);
6473 return ERR_PTR(error
);
6477 mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
6479 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6480 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(css
));
6482 if (css
->cgroup
->id
> MEM_CGROUP_ID_MAX
)
6488 mutex_lock(&memcg_create_mutex
);
6490 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6491 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6492 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6494 if (parent
->use_hierarchy
) {
6495 res_counter_init(&memcg
->res
, &parent
->res
);
6496 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6497 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6500 * No need to take a reference to the parent because cgroup
6501 * core guarantees its existence.
6504 res_counter_init(&memcg
->res
, NULL
);
6505 res_counter_init(&memcg
->memsw
, NULL
);
6506 res_counter_init(&memcg
->kmem
, NULL
);
6508 * Deeper hierachy with use_hierarchy == false doesn't make
6509 * much sense so let cgroup subsystem know about this
6510 * unfortunate state in our controller.
6512 if (parent
!= root_mem_cgroup
)
6513 memory_cgrp_subsys
.broken_hierarchy
= true;
6515 mutex_unlock(&memcg_create_mutex
);
6517 return memcg_init_kmem(memcg
, &memory_cgrp_subsys
);
6521 * Announce all parents that a group from their hierarchy is gone.
6523 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup
*memcg
)
6525 struct mem_cgroup
*parent
= memcg
;
6527 while ((parent
= parent_mem_cgroup(parent
)))
6528 mem_cgroup_iter_invalidate(parent
);
6531 * if the root memcg is not hierarchical we have to check it
6534 if (!root_mem_cgroup
->use_hierarchy
)
6535 mem_cgroup_iter_invalidate(root_mem_cgroup
);
6538 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
6540 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6541 struct mem_cgroup_event
*event
, *tmp
;
6542 struct cgroup_subsys_state
*iter
;
6545 * Unregister events and notify userspace.
6546 * Notify userspace about cgroup removing only after rmdir of cgroup
6547 * directory to avoid race between userspace and kernelspace.
6549 spin_lock(&memcg
->event_list_lock
);
6550 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
6551 list_del_init(&event
->list
);
6552 schedule_work(&event
->remove
);
6554 spin_unlock(&memcg
->event_list_lock
);
6556 kmem_cgroup_css_offline(memcg
);
6558 mem_cgroup_invalidate_reclaim_iterators(memcg
);
6561 * This requires that offlining is serialized. Right now that is
6562 * guaranteed because css_killed_work_fn() holds the cgroup_mutex.
6564 css_for_each_descendant_post(iter
, css
)
6565 mem_cgroup_reparent_charges(mem_cgroup_from_css(iter
));
6567 mem_cgroup_destroy_all_caches(memcg
);
6568 vmpressure_cleanup(&memcg
->vmpressure
);
6571 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
6573 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6575 * XXX: css_offline() would be where we should reparent all
6576 * memory to prepare the cgroup for destruction. However,
6577 * memcg does not do css_tryget() and res_counter charging
6578 * under the same RCU lock region, which means that charging
6579 * could race with offlining. Offlining only happens to
6580 * cgroups with no tasks in them but charges can show up
6581 * without any tasks from the swapin path when the target
6582 * memcg is looked up from the swapout record and not from the
6583 * current task as it usually is. A race like this can leak
6584 * charges and put pages with stale cgroup pointers into
6588 * lookup_swap_cgroup_id()
6590 * mem_cgroup_lookup()
6593 * disable css_tryget()
6596 * reparent_charges()
6597 * res_counter_charge()
6600 * pc->mem_cgroup = dead memcg
6603 * The bulk of the charges are still moved in offline_css() to
6604 * avoid pinning a lot of pages in case a long-term reference
6605 * like a swapout record is deferring the css_free() to long
6606 * after offlining. But this makes sure we catch any charges
6607 * made after offlining:
6609 mem_cgroup_reparent_charges(memcg
);
6611 memcg_destroy_kmem(memcg
);
6612 __mem_cgroup_free(memcg
);
6616 /* Handlers for move charge at task migration. */
6617 #define PRECHARGE_COUNT_AT_ONCE 256
6618 static int mem_cgroup_do_precharge(unsigned long count
)
6621 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6622 struct mem_cgroup
*memcg
= mc
.to
;
6624 if (mem_cgroup_is_root(memcg
)) {
6625 mc
.precharge
+= count
;
6626 /* we don't need css_get for root */
6629 /* try to charge at once */
6631 struct res_counter
*dummy
;
6633 * "memcg" cannot be under rmdir() because we've already checked
6634 * by cgroup_lock_live_cgroup() that it is not removed and we
6635 * are still under the same cgroup_mutex. So we can postpone
6638 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6640 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6641 PAGE_SIZE
* count
, &dummy
)) {
6642 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6645 mc
.precharge
+= count
;
6649 /* fall back to one by one charge */
6651 if (signal_pending(current
)) {
6655 if (!batch_count
--) {
6656 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6659 ret
= __mem_cgroup_try_charge(NULL
,
6660 GFP_KERNEL
, 1, &memcg
, false);
6662 /* mem_cgroup_clear_mc() will do uncharge later */
6670 * get_mctgt_type - get target type of moving charge
6671 * @vma: the vma the pte to be checked belongs
6672 * @addr: the address corresponding to the pte to be checked
6673 * @ptent: the pte to be checked
6674 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6677 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6678 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6679 * move charge. if @target is not NULL, the page is stored in target->page
6680 * with extra refcnt got(Callers should handle it).
6681 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6682 * target for charge migration. if @target is not NULL, the entry is stored
6685 * Called with pte lock held.
6692 enum mc_target_type
{
6698 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6699 unsigned long addr
, pte_t ptent
)
6701 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6703 if (!page
|| !page_mapped(page
))
6705 if (PageAnon(page
)) {
6706 /* we don't move shared anon */
6709 } else if (!move_file())
6710 /* we ignore mapcount for file pages */
6712 if (!get_page_unless_zero(page
))
6719 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6720 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6722 struct page
*page
= NULL
;
6723 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6725 if (!move_anon() || non_swap_entry(ent
))
6728 * Because lookup_swap_cache() updates some statistics counter,
6729 * we call find_get_page() with swapper_space directly.
6731 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6732 if (do_swap_account
)
6733 entry
->val
= ent
.val
;
6738 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6739 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6745 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6746 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6748 struct page
*page
= NULL
;
6749 struct address_space
*mapping
;
6752 if (!vma
->vm_file
) /* anonymous vma */
6757 mapping
= vma
->vm_file
->f_mapping
;
6758 if (pte_none(ptent
))
6759 pgoff
= linear_page_index(vma
, addr
);
6760 else /* pte_file(ptent) is true */
6761 pgoff
= pte_to_pgoff(ptent
);
6763 /* page is moved even if it's not RSS of this task(page-faulted). */
6764 page
= find_get_page(mapping
, pgoff
);
6767 /* shmem/tmpfs may report page out on swap: account for that too. */
6768 if (radix_tree_exceptional_entry(page
)) {
6769 swp_entry_t swap
= radix_to_swp_entry(page
);
6770 if (do_swap_account
)
6772 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6778 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6779 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6781 struct page
*page
= NULL
;
6782 struct page_cgroup
*pc
;
6783 enum mc_target_type ret
= MC_TARGET_NONE
;
6784 swp_entry_t ent
= { .val
= 0 };
6786 if (pte_present(ptent
))
6787 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6788 else if (is_swap_pte(ptent
))
6789 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6790 else if (pte_none(ptent
) || pte_file(ptent
))
6791 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6793 if (!page
&& !ent
.val
)
6796 pc
= lookup_page_cgroup(page
);
6798 * Do only loose check w/o page_cgroup lock.
6799 * mem_cgroup_move_account() checks the pc is valid or not under
6802 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6803 ret
= MC_TARGET_PAGE
;
6805 target
->page
= page
;
6807 if (!ret
|| !target
)
6810 /* There is a swap entry and a page doesn't exist or isn't charged */
6811 if (ent
.val
&& !ret
&&
6812 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
6813 ret
= MC_TARGET_SWAP
;
6820 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6822 * We don't consider swapping or file mapped pages because THP does not
6823 * support them for now.
6824 * Caller should make sure that pmd_trans_huge(pmd) is true.
6826 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6827 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6829 struct page
*page
= NULL
;
6830 struct page_cgroup
*pc
;
6831 enum mc_target_type ret
= MC_TARGET_NONE
;
6833 page
= pmd_page(pmd
);
6834 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
6837 pc
= lookup_page_cgroup(page
);
6838 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6839 ret
= MC_TARGET_PAGE
;
6842 target
->page
= page
;
6848 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6849 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6851 return MC_TARGET_NONE
;
6855 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6856 unsigned long addr
, unsigned long end
,
6857 struct mm_walk
*walk
)
6859 struct vm_area_struct
*vma
= walk
->private;
6863 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
6864 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6865 mc
.precharge
+= HPAGE_PMD_NR
;
6870 if (pmd_trans_unstable(pmd
))
6872 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6873 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6874 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6875 mc
.precharge
++; /* increment precharge temporarily */
6876 pte_unmap_unlock(pte
- 1, ptl
);
6882 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6884 unsigned long precharge
;
6885 struct vm_area_struct
*vma
;
6887 down_read(&mm
->mmap_sem
);
6888 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6889 struct mm_walk mem_cgroup_count_precharge_walk
= {
6890 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6894 if (is_vm_hugetlb_page(vma
))
6896 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6897 &mem_cgroup_count_precharge_walk
);
6899 up_read(&mm
->mmap_sem
);
6901 precharge
= mc
.precharge
;
6907 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6909 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6911 VM_BUG_ON(mc
.moving_task
);
6912 mc
.moving_task
= current
;
6913 return mem_cgroup_do_precharge(precharge
);
6916 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6917 static void __mem_cgroup_clear_mc(void)
6919 struct mem_cgroup
*from
= mc
.from
;
6920 struct mem_cgroup
*to
= mc
.to
;
6923 /* we must uncharge all the leftover precharges from mc.to */
6925 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6929 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6930 * we must uncharge here.
6932 if (mc
.moved_charge
) {
6933 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6934 mc
.moved_charge
= 0;
6936 /* we must fixup refcnts and charges */
6937 if (mc
.moved_swap
) {
6938 /* uncharge swap account from the old cgroup */
6939 if (!mem_cgroup_is_root(mc
.from
))
6940 res_counter_uncharge(&mc
.from
->memsw
,
6941 PAGE_SIZE
* mc
.moved_swap
);
6943 for (i
= 0; i
< mc
.moved_swap
; i
++)
6944 css_put(&mc
.from
->css
);
6946 if (!mem_cgroup_is_root(mc
.to
)) {
6948 * we charged both to->res and to->memsw, so we should
6951 res_counter_uncharge(&mc
.to
->res
,
6952 PAGE_SIZE
* mc
.moved_swap
);
6954 /* we've already done css_get(mc.to) */
6957 memcg_oom_recover(from
);
6958 memcg_oom_recover(to
);
6959 wake_up_all(&mc
.waitq
);
6962 static void mem_cgroup_clear_mc(void)
6964 struct mem_cgroup
*from
= mc
.from
;
6967 * we must clear moving_task before waking up waiters at the end of
6970 mc
.moving_task
= NULL
;
6971 __mem_cgroup_clear_mc();
6972 spin_lock(&mc
.lock
);
6975 spin_unlock(&mc
.lock
);
6976 mem_cgroup_end_move(from
);
6979 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
6980 struct cgroup_taskset
*tset
)
6982 struct task_struct
*p
= cgroup_taskset_first(tset
);
6984 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6985 unsigned long move_charge_at_immigrate
;
6988 * We are now commited to this value whatever it is. Changes in this
6989 * tunable will only affect upcoming migrations, not the current one.
6990 * So we need to save it, and keep it going.
6992 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
6993 if (move_charge_at_immigrate
) {
6994 struct mm_struct
*mm
;
6995 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
6997 VM_BUG_ON(from
== memcg
);
6999 mm
= get_task_mm(p
);
7002 /* We move charges only when we move a owner of the mm */
7003 if (mm
->owner
== p
) {
7006 VM_BUG_ON(mc
.precharge
);
7007 VM_BUG_ON(mc
.moved_charge
);
7008 VM_BUG_ON(mc
.moved_swap
);
7009 mem_cgroup_start_move(from
);
7010 spin_lock(&mc
.lock
);
7013 mc
.immigrate_flags
= move_charge_at_immigrate
;
7014 spin_unlock(&mc
.lock
);
7015 /* We set mc.moving_task later */
7017 ret
= mem_cgroup_precharge_mc(mm
);
7019 mem_cgroup_clear_mc();
7026 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7027 struct cgroup_taskset
*tset
)
7029 mem_cgroup_clear_mc();
7032 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
7033 unsigned long addr
, unsigned long end
,
7034 struct mm_walk
*walk
)
7037 struct vm_area_struct
*vma
= walk
->private;
7040 enum mc_target_type target_type
;
7041 union mc_target target
;
7043 struct page_cgroup
*pc
;
7046 * We don't take compound_lock() here but no race with splitting thp
7048 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
7049 * under splitting, which means there's no concurrent thp split,
7050 * - if another thread runs into split_huge_page() just after we
7051 * entered this if-block, the thread must wait for page table lock
7052 * to be unlocked in __split_huge_page_splitting(), where the main
7053 * part of thp split is not executed yet.
7055 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
7056 if (mc
.precharge
< HPAGE_PMD_NR
) {
7060 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
7061 if (target_type
== MC_TARGET_PAGE
) {
7063 if (!isolate_lru_page(page
)) {
7064 pc
= lookup_page_cgroup(page
);
7065 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
7066 pc
, mc
.from
, mc
.to
)) {
7067 mc
.precharge
-= HPAGE_PMD_NR
;
7068 mc
.moved_charge
+= HPAGE_PMD_NR
;
7070 putback_lru_page(page
);
7078 if (pmd_trans_unstable(pmd
))
7081 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
7082 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
7083 pte_t ptent
= *(pte
++);
7089 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
7090 case MC_TARGET_PAGE
:
7092 if (isolate_lru_page(page
))
7094 pc
= lookup_page_cgroup(page
);
7095 if (!mem_cgroup_move_account(page
, 1, pc
,
7098 /* we uncharge from mc.from later. */
7101 putback_lru_page(page
);
7102 put
: /* get_mctgt_type() gets the page */
7105 case MC_TARGET_SWAP
:
7107 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
7109 /* we fixup refcnts and charges later. */
7117 pte_unmap_unlock(pte
- 1, ptl
);
7122 * We have consumed all precharges we got in can_attach().
7123 * We try charge one by one, but don't do any additional
7124 * charges to mc.to if we have failed in charge once in attach()
7127 ret
= mem_cgroup_do_precharge(1);
7135 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
7137 struct vm_area_struct
*vma
;
7139 lru_add_drain_all();
7141 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
7143 * Someone who are holding the mmap_sem might be waiting in
7144 * waitq. So we cancel all extra charges, wake up all waiters,
7145 * and retry. Because we cancel precharges, we might not be able
7146 * to move enough charges, but moving charge is a best-effort
7147 * feature anyway, so it wouldn't be a big problem.
7149 __mem_cgroup_clear_mc();
7153 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
7155 struct mm_walk mem_cgroup_move_charge_walk
= {
7156 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
7160 if (is_vm_hugetlb_page(vma
))
7162 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
7163 &mem_cgroup_move_charge_walk
);
7166 * means we have consumed all precharges and failed in
7167 * doing additional charge. Just abandon here.
7171 up_read(&mm
->mmap_sem
);
7174 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7175 struct cgroup_taskset
*tset
)
7177 struct task_struct
*p
= cgroup_taskset_first(tset
);
7178 struct mm_struct
*mm
= get_task_mm(p
);
7182 mem_cgroup_move_charge(mm
);
7186 mem_cgroup_clear_mc();
7188 #else /* !CONFIG_MMU */
7189 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7190 struct cgroup_taskset
*tset
)
7194 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7195 struct cgroup_taskset
*tset
)
7198 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7199 struct cgroup_taskset
*tset
)
7205 * Cgroup retains root cgroups across [un]mount cycles making it necessary
7206 * to verify sane_behavior flag on each mount attempt.
7208 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
7211 * use_hierarchy is forced with sane_behavior. cgroup core
7212 * guarantees that @root doesn't have any children, so turning it
7213 * on for the root memcg is enough.
7215 if (cgroup_sane_behavior(root_css
->cgroup
))
7216 mem_cgroup_from_css(root_css
)->use_hierarchy
= true;
7219 struct cgroup_subsys memory_cgrp_subsys
= {
7220 .css_alloc
= mem_cgroup_css_alloc
,
7221 .css_online
= mem_cgroup_css_online
,
7222 .css_offline
= mem_cgroup_css_offline
,
7223 .css_free
= mem_cgroup_css_free
,
7224 .can_attach
= mem_cgroup_can_attach
,
7225 .cancel_attach
= mem_cgroup_cancel_attach
,
7226 .attach
= mem_cgroup_move_task
,
7227 .bind
= mem_cgroup_bind
,
7228 .base_cftypes
= mem_cgroup_files
,
7232 #ifdef CONFIG_MEMCG_SWAP
7233 static int __init
enable_swap_account(char *s
)
7235 if (!strcmp(s
, "1"))
7236 really_do_swap_account
= 1;
7237 else if (!strcmp(s
, "0"))
7238 really_do_swap_account
= 0;
7241 __setup("swapaccount=", enable_swap_account
);
7243 static void __init
memsw_file_init(void)
7245 WARN_ON(cgroup_add_cftypes(&memory_cgrp_subsys
, memsw_cgroup_files
));
7248 static void __init
enable_swap_cgroup(void)
7250 if (!mem_cgroup_disabled() && really_do_swap_account
) {
7251 do_swap_account
= 1;
7257 static void __init
enable_swap_cgroup(void)
7263 * subsys_initcall() for memory controller.
7265 * Some parts like hotcpu_notifier() have to be initialized from this context
7266 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
7267 * everything that doesn't depend on a specific mem_cgroup structure should
7268 * be initialized from here.
7270 static int __init
mem_cgroup_init(void)
7272 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
7273 enable_swap_cgroup();
7274 mem_cgroup_soft_limit_tree_init();
7278 subsys_initcall(mem_cgroup_init
);