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/vmalloc.h>
53 #include <linux/vmpressure.h>
54 #include <linux/mm_inline.h>
55 #include <linux/page_cgroup.h>
56 #include <linux/cpu.h>
57 #include <linux/oom.h>
58 #include <linux/lockdep.h>
59 #include <linux/file.h>
63 #include <net/tcp_memcontrol.h>
66 #include <asm/uaccess.h>
68 #include <trace/events/vmscan.h>
70 struct cgroup_subsys mem_cgroup_subsys __read_mostly
;
71 EXPORT_SYMBOL(mem_cgroup_subsys
);
73 #define MEM_CGROUP_RECLAIM_RETRIES 5
74 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
76 #ifdef CONFIG_MEMCG_SWAP
77 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
78 int do_swap_account __read_mostly
;
80 /* for remember boot option*/
81 #ifdef CONFIG_MEMCG_SWAP_ENABLED
82 static int really_do_swap_account __initdata
= 1;
84 static int really_do_swap_account __initdata
= 0;
88 #define do_swap_account 0
92 static const char * const mem_cgroup_stat_names
[] = {
101 enum mem_cgroup_events_index
{
102 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
103 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
104 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
105 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
106 MEM_CGROUP_EVENTS_NSTATS
,
109 static const char * const mem_cgroup_events_names
[] = {
116 static const char * const mem_cgroup_lru_names
[] = {
125 * Per memcg event counter is incremented at every pagein/pageout. With THP,
126 * it will be incremated by the number of pages. This counter is used for
127 * for trigger some periodic events. This is straightforward and better
128 * than using jiffies etc. to handle periodic memcg event.
130 enum mem_cgroup_events_target
{
131 MEM_CGROUP_TARGET_THRESH
,
132 MEM_CGROUP_TARGET_SOFTLIMIT
,
133 MEM_CGROUP_TARGET_NUMAINFO
,
136 #define THRESHOLDS_EVENTS_TARGET 128
137 #define SOFTLIMIT_EVENTS_TARGET 1024
138 #define NUMAINFO_EVENTS_TARGET 1024
140 struct mem_cgroup_stat_cpu
{
141 long count
[MEM_CGROUP_STAT_NSTATS
];
142 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
143 unsigned long nr_page_events
;
144 unsigned long targets
[MEM_CGROUP_NTARGETS
];
147 struct mem_cgroup_reclaim_iter
{
149 * last scanned hierarchy member. Valid only if last_dead_count
150 * matches memcg->dead_count of the hierarchy root group.
152 struct mem_cgroup
*last_visited
;
153 unsigned long last_dead_count
;
155 /* scan generation, increased every round-trip */
156 unsigned int generation
;
160 * per-zone information in memory controller.
162 struct mem_cgroup_per_zone
{
163 struct lruvec lruvec
;
164 unsigned long lru_size
[NR_LRU_LISTS
];
166 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
168 struct rb_node tree_node
; /* RB tree node */
169 unsigned long long usage_in_excess
;/* Set to the value by which */
170 /* the soft limit is exceeded*/
172 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
173 /* use container_of */
176 struct mem_cgroup_per_node
{
177 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
181 * Cgroups above their limits are maintained in a RB-Tree, independent of
182 * their hierarchy representation
185 struct mem_cgroup_tree_per_zone
{
186 struct rb_root rb_root
;
190 struct mem_cgroup_tree_per_node
{
191 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
194 struct mem_cgroup_tree
{
195 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
198 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
200 struct mem_cgroup_threshold
{
201 struct eventfd_ctx
*eventfd
;
206 struct mem_cgroup_threshold_ary
{
207 /* An array index points to threshold just below or equal to usage. */
208 int current_threshold
;
209 /* Size of entries[] */
211 /* Array of thresholds */
212 struct mem_cgroup_threshold entries
[0];
215 struct mem_cgroup_thresholds
{
216 /* Primary thresholds array */
217 struct mem_cgroup_threshold_ary
*primary
;
219 * Spare threshold array.
220 * This is needed to make mem_cgroup_unregister_event() "never fail".
221 * It must be able to store at least primary->size - 1 entries.
223 struct mem_cgroup_threshold_ary
*spare
;
227 struct mem_cgroup_eventfd_list
{
228 struct list_head list
;
229 struct eventfd_ctx
*eventfd
;
233 * cgroup_event represents events which userspace want to receive.
235 struct mem_cgroup_event
{
237 * memcg which the event belongs to.
239 struct mem_cgroup
*memcg
;
241 * eventfd to signal userspace about the event.
243 struct eventfd_ctx
*eventfd
;
245 * Each of these stored in a list by the cgroup.
247 struct list_head list
;
249 * register_event() callback will be used to add new userspace
250 * waiter for changes related to this event. Use eventfd_signal()
251 * on eventfd to send notification to userspace.
253 int (*register_event
)(struct mem_cgroup
*memcg
,
254 struct eventfd_ctx
*eventfd
, const char *args
);
256 * unregister_event() callback will be called when userspace closes
257 * the eventfd or on cgroup removing. This callback must be set,
258 * if you want provide notification functionality.
260 void (*unregister_event
)(struct mem_cgroup
*memcg
,
261 struct eventfd_ctx
*eventfd
);
263 * All fields below needed to unregister event when
264 * userspace closes eventfd.
267 wait_queue_head_t
*wqh
;
269 struct work_struct remove
;
272 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
273 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
276 * The memory controller data structure. The memory controller controls both
277 * page cache and RSS per cgroup. We would eventually like to provide
278 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
279 * to help the administrator determine what knobs to tune.
281 * TODO: Add a water mark for the memory controller. Reclaim will begin when
282 * we hit the water mark. May be even add a low water mark, such that
283 * no reclaim occurs from a cgroup at it's low water mark, this is
284 * a feature that will be implemented much later in the future.
287 struct cgroup_subsys_state css
;
289 * the counter to account for memory usage
291 struct res_counter res
;
293 /* vmpressure notifications */
294 struct vmpressure vmpressure
;
297 * the counter to account for mem+swap usage.
299 struct res_counter memsw
;
302 * the counter to account for kernel memory usage.
304 struct res_counter kmem
;
306 * Should the accounting and control be hierarchical, per subtree?
309 unsigned long kmem_account_flags
; /* See KMEM_ACCOUNTED_*, below */
313 atomic_t oom_wakeups
;
316 /* OOM-Killer disable */
317 int oom_kill_disable
;
319 /* set when res.limit == memsw.limit */
320 bool memsw_is_minimum
;
322 /* protect arrays of thresholds */
323 struct mutex thresholds_lock
;
325 /* thresholds for memory usage. RCU-protected */
326 struct mem_cgroup_thresholds thresholds
;
328 /* thresholds for mem+swap usage. RCU-protected */
329 struct mem_cgroup_thresholds memsw_thresholds
;
331 /* For oom notifier event fd */
332 struct list_head oom_notify
;
335 * Should we move charges of a task when a task is moved into this
336 * mem_cgroup ? And what type of charges should we move ?
338 unsigned long move_charge_at_immigrate
;
340 * set > 0 if pages under this cgroup are moving to other cgroup.
342 atomic_t moving_account
;
343 /* taken only while moving_account > 0 */
344 spinlock_t move_lock
;
348 struct mem_cgroup_stat_cpu __percpu
*stat
;
350 * used when a cpu is offlined or other synchronizations
351 * See mem_cgroup_read_stat().
353 struct mem_cgroup_stat_cpu nocpu_base
;
354 spinlock_t pcp_counter_lock
;
357 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
358 struct cg_proto tcp_mem
;
360 #if defined(CONFIG_MEMCG_KMEM)
361 /* analogous to slab_common's slab_caches list. per-memcg */
362 struct list_head memcg_slab_caches
;
363 /* Not a spinlock, we can take a lot of time walking the list */
364 struct mutex slab_caches_mutex
;
365 /* Index in the kmem_cache->memcg_params->memcg_caches array */
369 int last_scanned_node
;
371 nodemask_t scan_nodes
;
372 atomic_t numainfo_events
;
373 atomic_t numainfo_updating
;
376 /* List of events which userspace want to receive */
377 struct list_head event_list
;
378 spinlock_t event_list_lock
;
380 struct mem_cgroup_per_node
*nodeinfo
[0];
381 /* WARNING: nodeinfo must be the last member here */
384 static size_t memcg_size(void)
386 return sizeof(struct mem_cgroup
) +
387 nr_node_ids
* sizeof(struct mem_cgroup_per_node
);
390 /* internal only representation about the status of kmem accounting. */
392 KMEM_ACCOUNTED_ACTIVE
= 0, /* accounted by this cgroup itself */
393 KMEM_ACCOUNTED_ACTIVATED
, /* static key enabled. */
394 KMEM_ACCOUNTED_DEAD
, /* dead memcg with pending kmem charges */
397 /* We account when limit is on, but only after call sites are patched */
398 #define KMEM_ACCOUNTED_MASK \
399 ((1 << KMEM_ACCOUNTED_ACTIVE) | (1 << KMEM_ACCOUNTED_ACTIVATED))
401 #ifdef CONFIG_MEMCG_KMEM
402 static inline void memcg_kmem_set_active(struct mem_cgroup
*memcg
)
404 set_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
407 static bool memcg_kmem_is_active(struct mem_cgroup
*memcg
)
409 return test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
);
412 static void memcg_kmem_set_activated(struct mem_cgroup
*memcg
)
414 set_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
417 static void memcg_kmem_clear_activated(struct mem_cgroup
*memcg
)
419 clear_bit(KMEM_ACCOUNTED_ACTIVATED
, &memcg
->kmem_account_flags
);
422 static void memcg_kmem_mark_dead(struct mem_cgroup
*memcg
)
425 * Our caller must use css_get() first, because memcg_uncharge_kmem()
426 * will call css_put() if it sees the memcg is dead.
429 if (test_bit(KMEM_ACCOUNTED_ACTIVE
, &memcg
->kmem_account_flags
))
430 set_bit(KMEM_ACCOUNTED_DEAD
, &memcg
->kmem_account_flags
);
433 static bool memcg_kmem_test_and_clear_dead(struct mem_cgroup
*memcg
)
435 return test_and_clear_bit(KMEM_ACCOUNTED_DEAD
,
436 &memcg
->kmem_account_flags
);
440 /* Stuffs for move charges at task migration. */
442 * Types of charges to be moved. "move_charge_at_immitgrate" and
443 * "immigrate_flags" are treated as a left-shifted bitmap of these types.
446 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
447 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
451 /* "mc" and its members are protected by cgroup_mutex */
452 static struct move_charge_struct
{
453 spinlock_t lock
; /* for from, to */
454 struct mem_cgroup
*from
;
455 struct mem_cgroup
*to
;
456 unsigned long immigrate_flags
;
457 unsigned long precharge
;
458 unsigned long moved_charge
;
459 unsigned long moved_swap
;
460 struct task_struct
*moving_task
; /* a task moving charges */
461 wait_queue_head_t waitq
; /* a waitq for other context */
463 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
464 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
467 static bool move_anon(void)
469 return test_bit(MOVE_CHARGE_TYPE_ANON
, &mc
.immigrate_flags
);
472 static bool move_file(void)
474 return test_bit(MOVE_CHARGE_TYPE_FILE
, &mc
.immigrate_flags
);
478 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
479 * limit reclaim to prevent infinite loops, if they ever occur.
481 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
482 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
485 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
486 MEM_CGROUP_CHARGE_TYPE_ANON
,
487 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
488 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
492 /* for encoding cft->private value on file */
500 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
501 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
502 #define MEMFILE_ATTR(val) ((val) & 0xffff)
503 /* Used for OOM nofiier */
504 #define OOM_CONTROL (0)
507 * Reclaim flags for mem_cgroup_hierarchical_reclaim
509 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
510 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
511 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
512 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
515 * The memcg_create_mutex will be held whenever a new cgroup is created.
516 * As a consequence, any change that needs to protect against new child cgroups
517 * appearing has to hold it as well.
519 static DEFINE_MUTEX(memcg_create_mutex
);
521 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
523 return s
? container_of(s
, struct mem_cgroup
, css
) : NULL
;
526 /* Some nice accessors for the vmpressure. */
527 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
530 memcg
= root_mem_cgroup
;
531 return &memcg
->vmpressure
;
534 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
536 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
539 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
541 return (memcg
== root_mem_cgroup
);
545 * We restrict the id in the range of [1, 65535], so it can fit into
548 #define MEM_CGROUP_ID_MAX USHRT_MAX
550 static inline unsigned short mem_cgroup_id(struct mem_cgroup
*memcg
)
553 * The ID of the root cgroup is 0, but memcg treat 0 as an
554 * invalid ID, so we return (cgroup_id + 1).
556 return memcg
->css
.cgroup
->id
+ 1;
559 static inline struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
561 struct cgroup_subsys_state
*css
;
563 css
= css_from_id(id
- 1, &mem_cgroup_subsys
);
564 return mem_cgroup_from_css(css
);
567 /* Writing them here to avoid exposing memcg's inner layout */
568 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
570 void sock_update_memcg(struct sock
*sk
)
572 if (mem_cgroup_sockets_enabled
) {
573 struct mem_cgroup
*memcg
;
574 struct cg_proto
*cg_proto
;
576 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
578 /* Socket cloning can throw us here with sk_cgrp already
579 * filled. It won't however, necessarily happen from
580 * process context. So the test for root memcg given
581 * the current task's memcg won't help us in this case.
583 * Respecting the original socket's memcg is a better
584 * decision in this case.
587 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
588 css_get(&sk
->sk_cgrp
->memcg
->css
);
593 memcg
= mem_cgroup_from_task(current
);
594 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
595 if (!mem_cgroup_is_root(memcg
) &&
596 memcg_proto_active(cg_proto
) && css_tryget(&memcg
->css
)) {
597 sk
->sk_cgrp
= cg_proto
;
602 EXPORT_SYMBOL(sock_update_memcg
);
604 void sock_release_memcg(struct sock
*sk
)
606 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
607 struct mem_cgroup
*memcg
;
608 WARN_ON(!sk
->sk_cgrp
->memcg
);
609 memcg
= sk
->sk_cgrp
->memcg
;
610 css_put(&sk
->sk_cgrp
->memcg
->css
);
614 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
616 if (!memcg
|| mem_cgroup_is_root(memcg
))
619 return &memcg
->tcp_mem
;
621 EXPORT_SYMBOL(tcp_proto_cgroup
);
623 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
625 if (!memcg_proto_activated(&memcg
->tcp_mem
))
627 static_key_slow_dec(&memcg_socket_limit_enabled
);
630 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
635 #ifdef CONFIG_MEMCG_KMEM
637 * This will be the memcg's index in each cache's ->memcg_params->memcg_caches.
638 * The main reason for not using cgroup id for this:
639 * this works better in sparse environments, where we have a lot of memcgs,
640 * but only a few kmem-limited. Or also, if we have, for instance, 200
641 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
642 * 200 entry array for that.
644 * The current size of the caches array is stored in
645 * memcg_limited_groups_array_size. It will double each time we have to
648 static DEFINE_IDA(kmem_limited_groups
);
649 int memcg_limited_groups_array_size
;
652 * MIN_SIZE is different than 1, because we would like to avoid going through
653 * the alloc/free process all the time. In a small machine, 4 kmem-limited
654 * cgroups is a reasonable guess. In the future, it could be a parameter or
655 * tunable, but that is strictly not necessary.
657 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
658 * this constant directly from cgroup, but it is understandable that this is
659 * better kept as an internal representation in cgroup.c. In any case, the
660 * cgrp_id space is not getting any smaller, and we don't have to necessarily
661 * increase ours as well if it increases.
663 #define MEMCG_CACHES_MIN_SIZE 4
664 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
667 * A lot of the calls to the cache allocation functions are expected to be
668 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
669 * conditional to this static branch, we'll have to allow modules that does
670 * kmem_cache_alloc and the such to see this symbol as well
672 struct static_key memcg_kmem_enabled_key
;
673 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
675 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
677 if (memcg_kmem_is_active(memcg
)) {
678 static_key_slow_dec(&memcg_kmem_enabled_key
);
679 ida_simple_remove(&kmem_limited_groups
, memcg
->kmemcg_id
);
682 * This check can't live in kmem destruction function,
683 * since the charges will outlive the cgroup
685 WARN_ON(res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0);
688 static void disarm_kmem_keys(struct mem_cgroup
*memcg
)
691 #endif /* CONFIG_MEMCG_KMEM */
693 static void disarm_static_keys(struct mem_cgroup
*memcg
)
695 disarm_sock_keys(memcg
);
696 disarm_kmem_keys(memcg
);
699 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
701 static struct mem_cgroup_per_zone
*
702 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
704 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
705 return &memcg
->nodeinfo
[nid
]->zoneinfo
[zid
];
708 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
713 static struct mem_cgroup_per_zone
*
714 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
716 int nid
= page_to_nid(page
);
717 int zid
= page_zonenum(page
);
719 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
722 static struct mem_cgroup_tree_per_zone
*
723 soft_limit_tree_node_zone(int nid
, int zid
)
725 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
728 static struct mem_cgroup_tree_per_zone
*
729 soft_limit_tree_from_page(struct page
*page
)
731 int nid
= page_to_nid(page
);
732 int zid
= page_zonenum(page
);
734 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
738 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
739 struct mem_cgroup_per_zone
*mz
,
740 struct mem_cgroup_tree_per_zone
*mctz
,
741 unsigned long long new_usage_in_excess
)
743 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
744 struct rb_node
*parent
= NULL
;
745 struct mem_cgroup_per_zone
*mz_node
;
750 mz
->usage_in_excess
= new_usage_in_excess
;
751 if (!mz
->usage_in_excess
)
755 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
757 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
760 * We can't avoid mem cgroups that are over their soft
761 * limit by the same amount
763 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
766 rb_link_node(&mz
->tree_node
, parent
, p
);
767 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
772 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
773 struct mem_cgroup_per_zone
*mz
,
774 struct mem_cgroup_tree_per_zone
*mctz
)
778 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
783 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
784 struct mem_cgroup_per_zone
*mz
,
785 struct mem_cgroup_tree_per_zone
*mctz
)
787 spin_lock(&mctz
->lock
);
788 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
789 spin_unlock(&mctz
->lock
);
793 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
795 unsigned long long excess
;
796 struct mem_cgroup_per_zone
*mz
;
797 struct mem_cgroup_tree_per_zone
*mctz
;
798 int nid
= page_to_nid(page
);
799 int zid
= page_zonenum(page
);
800 mctz
= soft_limit_tree_from_page(page
);
803 * Necessary to update all ancestors when hierarchy is used.
804 * because their event counter is not touched.
806 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
807 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
808 excess
= res_counter_soft_limit_excess(&memcg
->res
);
810 * We have to update the tree if mz is on RB-tree or
811 * mem is over its softlimit.
813 if (excess
|| mz
->on_tree
) {
814 spin_lock(&mctz
->lock
);
815 /* if on-tree, remove it */
817 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
819 * Insert again. mz->usage_in_excess will be updated.
820 * If excess is 0, no tree ops.
822 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
823 spin_unlock(&mctz
->lock
);
828 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
831 struct mem_cgroup_per_zone
*mz
;
832 struct mem_cgroup_tree_per_zone
*mctz
;
834 for_each_node(node
) {
835 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
836 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
837 mctz
= soft_limit_tree_node_zone(node
, zone
);
838 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
843 static struct mem_cgroup_per_zone
*
844 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
846 struct rb_node
*rightmost
= NULL
;
847 struct mem_cgroup_per_zone
*mz
;
851 rightmost
= rb_last(&mctz
->rb_root
);
853 goto done
; /* Nothing to reclaim from */
855 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
857 * Remove the node now but someone else can add it back,
858 * we will to add it back at the end of reclaim to its correct
859 * position in the tree.
861 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
862 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
863 !css_tryget(&mz
->memcg
->css
))
869 static struct mem_cgroup_per_zone
*
870 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
872 struct mem_cgroup_per_zone
*mz
;
874 spin_lock(&mctz
->lock
);
875 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
876 spin_unlock(&mctz
->lock
);
881 * Implementation Note: reading percpu statistics for memcg.
883 * Both of vmstat[] and percpu_counter has threshold and do periodic
884 * synchronization to implement "quick" read. There are trade-off between
885 * reading cost and precision of value. Then, we may have a chance to implement
886 * a periodic synchronizion of counter in memcg's counter.
888 * But this _read() function is used for user interface now. The user accounts
889 * memory usage by memory cgroup and he _always_ requires exact value because
890 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
891 * have to visit all online cpus and make sum. So, for now, unnecessary
892 * synchronization is not implemented. (just implemented for cpu hotplug)
894 * If there are kernel internal actions which can make use of some not-exact
895 * value, and reading all cpu value can be performance bottleneck in some
896 * common workload, threashold and synchonization as vmstat[] should be
899 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
900 enum mem_cgroup_stat_index idx
)
906 for_each_online_cpu(cpu
)
907 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
908 #ifdef CONFIG_HOTPLUG_CPU
909 spin_lock(&memcg
->pcp_counter_lock
);
910 val
+= memcg
->nocpu_base
.count
[idx
];
911 spin_unlock(&memcg
->pcp_counter_lock
);
917 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
920 int val
= (charge
) ? 1 : -1;
921 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
924 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
925 enum mem_cgroup_events_index idx
)
927 unsigned long val
= 0;
931 for_each_online_cpu(cpu
)
932 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
933 #ifdef CONFIG_HOTPLUG_CPU
934 spin_lock(&memcg
->pcp_counter_lock
);
935 val
+= memcg
->nocpu_base
.events
[idx
];
936 spin_unlock(&memcg
->pcp_counter_lock
);
942 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
944 bool anon
, int nr_pages
)
949 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
950 * counted as CACHE even if it's on ANON LRU.
953 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
956 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
959 if (PageTransHuge(page
))
960 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
963 /* pagein of a big page is an event. So, ignore page size */
965 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
967 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
968 nr_pages
= -nr_pages
; /* for event */
971 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
977 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
979 struct mem_cgroup_per_zone
*mz
;
981 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
982 return mz
->lru_size
[lru
];
986 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
987 unsigned int lru_mask
)
989 struct mem_cgroup_per_zone
*mz
;
991 unsigned long ret
= 0;
993 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
996 if (BIT(lru
) & lru_mask
)
997 ret
+= mz
->lru_size
[lru
];
1002 static unsigned long
1003 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
1004 int nid
, unsigned int lru_mask
)
1009 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
1010 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
1011 nid
, zid
, lru_mask
);
1016 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
1017 unsigned int lru_mask
)
1022 for_each_node_state(nid
, N_MEMORY
)
1023 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
1027 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
1028 enum mem_cgroup_events_target target
)
1030 unsigned long val
, next
;
1032 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
1033 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
1034 /* from time_after() in jiffies.h */
1035 if ((long)next
- (long)val
< 0) {
1037 case MEM_CGROUP_TARGET_THRESH
:
1038 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
1040 case MEM_CGROUP_TARGET_SOFTLIMIT
:
1041 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
1043 case MEM_CGROUP_TARGET_NUMAINFO
:
1044 next
= val
+ NUMAINFO_EVENTS_TARGET
;
1049 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
1056 * Check events in order.
1059 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
1062 /* threshold event is triggered in finer grain than soft limit */
1063 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
1064 MEM_CGROUP_TARGET_THRESH
))) {
1066 bool do_numainfo __maybe_unused
;
1068 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
1069 MEM_CGROUP_TARGET_SOFTLIMIT
);
1070 #if MAX_NUMNODES > 1
1071 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
1072 MEM_CGROUP_TARGET_NUMAINFO
);
1076 mem_cgroup_threshold(memcg
);
1077 if (unlikely(do_softlimit
))
1078 mem_cgroup_update_tree(memcg
, page
);
1079 #if MAX_NUMNODES > 1
1080 if (unlikely(do_numainfo
))
1081 atomic_inc(&memcg
->numainfo_events
);
1087 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
1090 * mm_update_next_owner() may clear mm->owner to NULL
1091 * if it races with swapoff, page migration, etc.
1092 * So this can be called with p == NULL.
1097 return mem_cgroup_from_css(task_css(p
, mem_cgroup_subsys_id
));
1100 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
1102 struct mem_cgroup
*memcg
= NULL
;
1107 * Because we have no locks, mm->owner's may be being moved to other
1108 * cgroup. We use css_tryget() here even if this looks
1109 * pessimistic (rather than adding locks here).
1113 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1114 if (unlikely(!memcg
))
1116 } while (!css_tryget(&memcg
->css
));
1122 * Returns a next (in a pre-order walk) alive memcg (with elevated css
1123 * ref. count) or NULL if the whole root's subtree has been visited.
1125 * helper function to be used by mem_cgroup_iter
1127 static struct mem_cgroup
*__mem_cgroup_iter_next(struct mem_cgroup
*root
,
1128 struct mem_cgroup
*last_visited
)
1130 struct cgroup_subsys_state
*prev_css
, *next_css
;
1132 prev_css
= last_visited
? &last_visited
->css
: NULL
;
1134 next_css
= css_next_descendant_pre(prev_css
, &root
->css
);
1137 * Even if we found a group we have to make sure it is
1138 * alive. css && !memcg means that the groups should be
1139 * skipped and we should continue the tree walk.
1140 * last_visited css is safe to use because it is
1141 * protected by css_get and the tree walk is rcu safe.
1144 struct mem_cgroup
*mem
= mem_cgroup_from_css(next_css
);
1146 if (css_tryget(&mem
->css
))
1149 prev_css
= next_css
;
1157 static void mem_cgroup_iter_invalidate(struct mem_cgroup
*root
)
1160 * When a group in the hierarchy below root is destroyed, the
1161 * hierarchy iterator can no longer be trusted since it might
1162 * have pointed to the destroyed group. Invalidate it.
1164 atomic_inc(&root
->dead_count
);
1167 static struct mem_cgroup
*
1168 mem_cgroup_iter_load(struct mem_cgroup_reclaim_iter
*iter
,
1169 struct mem_cgroup
*root
,
1172 struct mem_cgroup
*position
= NULL
;
1174 * A cgroup destruction happens in two stages: offlining and
1175 * release. They are separated by a RCU grace period.
1177 * If the iterator is valid, we may still race with an
1178 * offlining. The RCU lock ensures the object won't be
1179 * released, tryget will fail if we lost the race.
1181 *sequence
= atomic_read(&root
->dead_count
);
1182 if (iter
->last_dead_count
== *sequence
) {
1184 position
= iter
->last_visited
;
1185 if (position
&& !css_tryget(&position
->css
))
1191 static void mem_cgroup_iter_update(struct mem_cgroup_reclaim_iter
*iter
,
1192 struct mem_cgroup
*last_visited
,
1193 struct mem_cgroup
*new_position
,
1197 css_put(&last_visited
->css
);
1199 * We store the sequence count from the time @last_visited was
1200 * loaded successfully instead of rereading it here so that we
1201 * don't lose destruction events in between. We could have
1202 * raced with the destruction of @new_position after all.
1204 iter
->last_visited
= new_position
;
1206 iter
->last_dead_count
= sequence
;
1210 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1211 * @root: hierarchy root
1212 * @prev: previously returned memcg, NULL on first invocation
1213 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1215 * Returns references to children of the hierarchy below @root, or
1216 * @root itself, or %NULL after a full round-trip.
1218 * Caller must pass the return value in @prev on subsequent
1219 * invocations for reference counting, or use mem_cgroup_iter_break()
1220 * to cancel a hierarchy walk before the round-trip is complete.
1222 * Reclaimers can specify a zone and a priority level in @reclaim to
1223 * divide up the memcgs in the hierarchy among all concurrent
1224 * reclaimers operating on the same zone and priority.
1226 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1227 struct mem_cgroup
*prev
,
1228 struct mem_cgroup_reclaim_cookie
*reclaim
)
1230 struct mem_cgroup
*memcg
= NULL
;
1231 struct mem_cgroup
*last_visited
= NULL
;
1233 if (mem_cgroup_disabled())
1237 root
= root_mem_cgroup
;
1239 if (prev
&& !reclaim
)
1240 last_visited
= prev
;
1242 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1250 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1251 int uninitialized_var(seq
);
1254 int nid
= zone_to_nid(reclaim
->zone
);
1255 int zid
= zone_idx(reclaim
->zone
);
1256 struct mem_cgroup_per_zone
*mz
;
1258 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
1259 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
1260 if (prev
&& reclaim
->generation
!= iter
->generation
) {
1261 iter
->last_visited
= NULL
;
1265 last_visited
= mem_cgroup_iter_load(iter
, root
, &seq
);
1268 memcg
= __mem_cgroup_iter_next(root
, last_visited
);
1271 mem_cgroup_iter_update(iter
, last_visited
, memcg
, seq
);
1275 else if (!prev
&& memcg
)
1276 reclaim
->generation
= iter
->generation
;
1285 if (prev
&& prev
!= root
)
1286 css_put(&prev
->css
);
1292 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1293 * @root: hierarchy root
1294 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1296 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1297 struct mem_cgroup
*prev
)
1300 root
= root_mem_cgroup
;
1301 if (prev
&& prev
!= root
)
1302 css_put(&prev
->css
);
1306 * Iteration constructs for visiting all cgroups (under a tree). If
1307 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1308 * be used for reference counting.
1310 #define for_each_mem_cgroup_tree(iter, root) \
1311 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1313 iter = mem_cgroup_iter(root, iter, NULL))
1315 #define for_each_mem_cgroup(iter) \
1316 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1318 iter = mem_cgroup_iter(NULL, iter, NULL))
1320 void __mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1322 struct mem_cgroup
*memcg
;
1325 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1326 if (unlikely(!memcg
))
1331 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1334 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1342 EXPORT_SYMBOL(__mem_cgroup_count_vm_event
);
1345 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1346 * @zone: zone of the wanted lruvec
1347 * @memcg: memcg of the wanted lruvec
1349 * Returns the lru list vector holding pages for the given @zone and
1350 * @mem. This can be the global zone lruvec, if the memory controller
1353 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1354 struct mem_cgroup
*memcg
)
1356 struct mem_cgroup_per_zone
*mz
;
1357 struct lruvec
*lruvec
;
1359 if (mem_cgroup_disabled()) {
1360 lruvec
= &zone
->lruvec
;
1364 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1365 lruvec
= &mz
->lruvec
;
1368 * Since a node can be onlined after the mem_cgroup was created,
1369 * we have to be prepared to initialize lruvec->zone here;
1370 * and if offlined then reonlined, we need to reinitialize it.
1372 if (unlikely(lruvec
->zone
!= zone
))
1373 lruvec
->zone
= zone
;
1378 * Following LRU functions are allowed to be used without PCG_LOCK.
1379 * Operations are called by routine of global LRU independently from memcg.
1380 * What we have to take care of here is validness of pc->mem_cgroup.
1382 * Changes to pc->mem_cgroup happens when
1385 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1386 * It is added to LRU before charge.
1387 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1388 * When moving account, the page is not on LRU. It's isolated.
1392 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1394 * @zone: zone of the page
1396 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1398 struct mem_cgroup_per_zone
*mz
;
1399 struct mem_cgroup
*memcg
;
1400 struct page_cgroup
*pc
;
1401 struct lruvec
*lruvec
;
1403 if (mem_cgroup_disabled()) {
1404 lruvec
= &zone
->lruvec
;
1408 pc
= lookup_page_cgroup(page
);
1409 memcg
= pc
->mem_cgroup
;
1412 * Surreptitiously switch any uncharged offlist page to root:
1413 * an uncharged page off lru does nothing to secure
1414 * its former mem_cgroup from sudden removal.
1416 * Our caller holds lru_lock, and PageCgroupUsed is updated
1417 * under page_cgroup lock: between them, they make all uses
1418 * of pc->mem_cgroup safe.
1420 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1421 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1423 mz
= page_cgroup_zoneinfo(memcg
, page
);
1424 lruvec
= &mz
->lruvec
;
1427 * Since a node can be onlined after the mem_cgroup was created,
1428 * we have to be prepared to initialize lruvec->zone here;
1429 * and if offlined then reonlined, we need to reinitialize it.
1431 if (unlikely(lruvec
->zone
!= zone
))
1432 lruvec
->zone
= zone
;
1437 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1438 * @lruvec: mem_cgroup per zone lru vector
1439 * @lru: index of lru list the page is sitting on
1440 * @nr_pages: positive when adding or negative when removing
1442 * This function must be called when a page is added to or removed from an
1445 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1448 struct mem_cgroup_per_zone
*mz
;
1449 unsigned long *lru_size
;
1451 if (mem_cgroup_disabled())
1454 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1455 lru_size
= mz
->lru_size
+ lru
;
1456 *lru_size
+= nr_pages
;
1457 VM_BUG_ON((long)(*lru_size
) < 0);
1461 * Checks whether given mem is same or in the root_mem_cgroup's
1464 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1465 struct mem_cgroup
*memcg
)
1467 if (root_memcg
== memcg
)
1469 if (!root_memcg
->use_hierarchy
|| !memcg
)
1471 return cgroup_is_descendant(memcg
->css
.cgroup
, root_memcg
->css
.cgroup
);
1474 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1475 struct mem_cgroup
*memcg
)
1480 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1485 bool task_in_mem_cgroup(struct task_struct
*task
,
1486 const struct mem_cgroup
*memcg
)
1488 struct mem_cgroup
*curr
= NULL
;
1489 struct task_struct
*p
;
1492 p
= find_lock_task_mm(task
);
1494 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1498 * All threads may have already detached their mm's, but the oom
1499 * killer still needs to detect if they have already been oom
1500 * killed to prevent needlessly killing additional tasks.
1503 curr
= mem_cgroup_from_task(task
);
1505 css_get(&curr
->css
);
1511 * We should check use_hierarchy of "memcg" not "curr". Because checking
1512 * use_hierarchy of "curr" here make this function true if hierarchy is
1513 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1514 * hierarchy(even if use_hierarchy is disabled in "memcg").
1516 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1517 css_put(&curr
->css
);
1521 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1523 unsigned long inactive_ratio
;
1524 unsigned long inactive
;
1525 unsigned long active
;
1528 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1529 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1531 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1533 inactive_ratio
= int_sqrt(10 * gb
);
1537 return inactive
* inactive_ratio
< active
;
1540 #define mem_cgroup_from_res_counter(counter, member) \
1541 container_of(counter, struct mem_cgroup, member)
1544 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1545 * @memcg: the memory cgroup
1547 * Returns the maximum amount of memory @mem can be charged with, in
1550 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1552 unsigned long long margin
;
1554 margin
= res_counter_margin(&memcg
->res
);
1555 if (do_swap_account
)
1556 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1557 return margin
>> PAGE_SHIFT
;
1560 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1563 if (!css_parent(&memcg
->css
))
1564 return vm_swappiness
;
1566 return memcg
->swappiness
;
1570 * memcg->moving_account is used for checking possibility that some thread is
1571 * calling move_account(). When a thread on CPU-A starts moving pages under
1572 * a memcg, other threads should check memcg->moving_account under
1573 * rcu_read_lock(), like this:
1577 * memcg->moving_account+1 if (memcg->mocing_account)
1579 * synchronize_rcu() update something.
1584 /* for quick checking without looking up memcg */
1585 atomic_t memcg_moving __read_mostly
;
1587 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1589 atomic_inc(&memcg_moving
);
1590 atomic_inc(&memcg
->moving_account
);
1594 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1597 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1598 * We check NULL in callee rather than caller.
1601 atomic_dec(&memcg_moving
);
1602 atomic_dec(&memcg
->moving_account
);
1607 * 2 routines for checking "mem" is under move_account() or not.
1609 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1610 * is used for avoiding races in accounting. If true,
1611 * pc->mem_cgroup may be overwritten.
1613 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1614 * under hierarchy of moving cgroups. This is for
1615 * waiting at hith-memory prressure caused by "move".
1618 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1620 VM_BUG_ON(!rcu_read_lock_held());
1621 return atomic_read(&memcg
->moving_account
) > 0;
1624 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1626 struct mem_cgroup
*from
;
1627 struct mem_cgroup
*to
;
1630 * Unlike task_move routines, we access mc.to, mc.from not under
1631 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1633 spin_lock(&mc
.lock
);
1639 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1640 || mem_cgroup_same_or_subtree(memcg
, to
);
1642 spin_unlock(&mc
.lock
);
1646 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1648 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1649 if (mem_cgroup_under_move(memcg
)) {
1651 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1652 /* moving charge context might have finished. */
1655 finish_wait(&mc
.waitq
, &wait
);
1663 * Take this lock when
1664 * - a code tries to modify page's memcg while it's USED.
1665 * - a code tries to modify page state accounting in a memcg.
1666 * see mem_cgroup_stolen(), too.
1668 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1669 unsigned long *flags
)
1671 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1674 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1675 unsigned long *flags
)
1677 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1680 #define K(x) ((x) << (PAGE_SHIFT-10))
1682 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1683 * @memcg: The memory cgroup that went over limit
1684 * @p: Task that is going to be killed
1686 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1689 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1691 struct cgroup
*task_cgrp
;
1692 struct cgroup
*mem_cgrp
;
1694 * Need a buffer in BSS, can't rely on allocations. The code relies
1695 * on the assumption that OOM is serialized for memory controller.
1696 * If this assumption is broken, revisit this code.
1698 static char memcg_name
[PATH_MAX
];
1700 struct mem_cgroup
*iter
;
1708 mem_cgrp
= memcg
->css
.cgroup
;
1709 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1711 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1714 * Unfortunately, we are unable to convert to a useful name
1715 * But we'll still print out the usage information
1722 pr_info("Task in %s killed", memcg_name
);
1725 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1733 * Continues from above, so we don't need an KERN_ level
1735 pr_cont(" as a result of limit of %s\n", memcg_name
);
1738 pr_info("memory: usage %llukB, limit %llukB, failcnt %llu\n",
1739 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1740 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1741 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1742 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %llu\n",
1743 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1744 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1745 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1746 pr_info("kmem: usage %llukB, limit %llukB, failcnt %llu\n",
1747 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) >> 10,
1748 res_counter_read_u64(&memcg
->kmem
, RES_LIMIT
) >> 10,
1749 res_counter_read_u64(&memcg
->kmem
, RES_FAILCNT
));
1751 for_each_mem_cgroup_tree(iter
, memcg
) {
1752 pr_info("Memory cgroup stats");
1755 ret
= cgroup_path(iter
->css
.cgroup
, memcg_name
, PATH_MAX
);
1757 pr_cont(" for %s", memcg_name
);
1761 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1762 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1764 pr_cont(" %s:%ldKB", mem_cgroup_stat_names
[i
],
1765 K(mem_cgroup_read_stat(iter
, i
)));
1768 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1769 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1770 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1777 * This function returns the number of memcg under hierarchy tree. Returns
1778 * 1(self count) if no children.
1780 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1783 struct mem_cgroup
*iter
;
1785 for_each_mem_cgroup_tree(iter
, memcg
)
1791 * Return the memory (and swap, if configured) limit for a memcg.
1793 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1797 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1800 * Do not consider swap space if we cannot swap due to swappiness
1802 if (mem_cgroup_swappiness(memcg
)) {
1805 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1806 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1809 * If memsw is finite and limits the amount of swap space
1810 * available to this memcg, return that limit.
1812 limit
= min(limit
, memsw
);
1818 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1821 struct mem_cgroup
*iter
;
1822 unsigned long chosen_points
= 0;
1823 unsigned long totalpages
;
1824 unsigned int points
= 0;
1825 struct task_struct
*chosen
= NULL
;
1828 * If current has a pending SIGKILL or is exiting, then automatically
1829 * select it. The goal is to allow it to allocate so that it may
1830 * quickly exit and free its memory.
1832 if (fatal_signal_pending(current
) || current
->flags
& PF_EXITING
) {
1833 set_thread_flag(TIF_MEMDIE
);
1837 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1838 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1839 for_each_mem_cgroup_tree(iter
, memcg
) {
1840 struct css_task_iter it
;
1841 struct task_struct
*task
;
1843 css_task_iter_start(&iter
->css
, &it
);
1844 while ((task
= css_task_iter_next(&it
))) {
1845 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1847 case OOM_SCAN_SELECT
:
1849 put_task_struct(chosen
);
1851 chosen_points
= ULONG_MAX
;
1852 get_task_struct(chosen
);
1854 case OOM_SCAN_CONTINUE
:
1856 case OOM_SCAN_ABORT
:
1857 css_task_iter_end(&it
);
1858 mem_cgroup_iter_break(memcg
, iter
);
1860 put_task_struct(chosen
);
1865 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1866 if (points
> chosen_points
) {
1868 put_task_struct(chosen
);
1870 chosen_points
= points
;
1871 get_task_struct(chosen
);
1874 css_task_iter_end(&it
);
1879 points
= chosen_points
* 1000 / totalpages
;
1880 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1881 NULL
, "Memory cgroup out of memory");
1884 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1886 unsigned long flags
)
1888 unsigned long total
= 0;
1889 bool noswap
= false;
1892 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1894 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1897 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1899 drain_all_stock_async(memcg
);
1900 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1902 * Allow limit shrinkers, which are triggered directly
1903 * by userspace, to catch signals and stop reclaim
1904 * after minimal progress, regardless of the margin.
1906 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1908 if (mem_cgroup_margin(memcg
))
1911 * If nothing was reclaimed after two attempts, there
1912 * may be no reclaimable pages in this hierarchy.
1921 * test_mem_cgroup_node_reclaimable
1922 * @memcg: the target memcg
1923 * @nid: the node ID to be checked.
1924 * @noswap : specify true here if the user wants flle only information.
1926 * This function returns whether the specified memcg contains any
1927 * reclaimable pages on a node. Returns true if there are any reclaimable
1928 * pages in the node.
1930 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1931 int nid
, bool noswap
)
1933 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1935 if (noswap
|| !total_swap_pages
)
1937 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1942 #if MAX_NUMNODES > 1
1945 * Always updating the nodemask is not very good - even if we have an empty
1946 * list or the wrong list here, we can start from some node and traverse all
1947 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1950 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1954 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1955 * pagein/pageout changes since the last update.
1957 if (!atomic_read(&memcg
->numainfo_events
))
1959 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1962 /* make a nodemask where this memcg uses memory from */
1963 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1965 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1967 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1968 node_clear(nid
, memcg
->scan_nodes
);
1971 atomic_set(&memcg
->numainfo_events
, 0);
1972 atomic_set(&memcg
->numainfo_updating
, 0);
1976 * Selecting a node where we start reclaim from. Because what we need is just
1977 * reducing usage counter, start from anywhere is O,K. Considering
1978 * memory reclaim from current node, there are pros. and cons.
1980 * Freeing memory from current node means freeing memory from a node which
1981 * we'll use or we've used. So, it may make LRU bad. And if several threads
1982 * hit limits, it will see a contention on a node. But freeing from remote
1983 * node means more costs for memory reclaim because of memory latency.
1985 * Now, we use round-robin. Better algorithm is welcomed.
1987 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1991 mem_cgroup_may_update_nodemask(memcg
);
1992 node
= memcg
->last_scanned_node
;
1994 node
= next_node(node
, memcg
->scan_nodes
);
1995 if (node
== MAX_NUMNODES
)
1996 node
= first_node(memcg
->scan_nodes
);
1998 * We call this when we hit limit, not when pages are added to LRU.
1999 * No LRU may hold pages because all pages are UNEVICTABLE or
2000 * memcg is too small and all pages are not on LRU. In that case,
2001 * we use curret node.
2003 if (unlikely(node
== MAX_NUMNODES
))
2004 node
= numa_node_id();
2006 memcg
->last_scanned_node
= node
;
2011 * Check all nodes whether it contains reclaimable pages or not.
2012 * For quick scan, we make use of scan_nodes. This will allow us to skip
2013 * unused nodes. But scan_nodes is lazily updated and may not cotain
2014 * enough new information. We need to do double check.
2016 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
2021 * quick check...making use of scan_node.
2022 * We can skip unused nodes.
2024 if (!nodes_empty(memcg
->scan_nodes
)) {
2025 for (nid
= first_node(memcg
->scan_nodes
);
2027 nid
= next_node(nid
, memcg
->scan_nodes
)) {
2029 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
2034 * Check rest of nodes.
2036 for_each_node_state(nid
, N_MEMORY
) {
2037 if (node_isset(nid
, memcg
->scan_nodes
))
2039 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
2046 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
2051 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
2053 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
2057 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
2060 unsigned long *total_scanned
)
2062 struct mem_cgroup
*victim
= NULL
;
2065 unsigned long excess
;
2066 unsigned long nr_scanned
;
2067 struct mem_cgroup_reclaim_cookie reclaim
= {
2072 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
2075 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
2080 * If we have not been able to reclaim
2081 * anything, it might because there are
2082 * no reclaimable pages under this hierarchy
2087 * We want to do more targeted reclaim.
2088 * excess >> 2 is not to excessive so as to
2089 * reclaim too much, nor too less that we keep
2090 * coming back to reclaim from this cgroup
2092 if (total
>= (excess
>> 2) ||
2093 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
2098 if (!mem_cgroup_reclaimable(victim
, false))
2100 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
2102 *total_scanned
+= nr_scanned
;
2103 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
2106 mem_cgroup_iter_break(root_memcg
, victim
);
2110 #ifdef CONFIG_LOCKDEP
2111 static struct lockdep_map memcg_oom_lock_dep_map
= {
2112 .name
= "memcg_oom_lock",
2116 static DEFINE_SPINLOCK(memcg_oom_lock
);
2119 * Check OOM-Killer is already running under our hierarchy.
2120 * If someone is running, return false.
2122 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
2124 struct mem_cgroup
*iter
, *failed
= NULL
;
2126 spin_lock(&memcg_oom_lock
);
2128 for_each_mem_cgroup_tree(iter
, memcg
) {
2129 if (iter
->oom_lock
) {
2131 * this subtree of our hierarchy is already locked
2132 * so we cannot give a lock.
2135 mem_cgroup_iter_break(memcg
, iter
);
2138 iter
->oom_lock
= true;
2143 * OK, we failed to lock the whole subtree so we have
2144 * to clean up what we set up to the failing subtree
2146 for_each_mem_cgroup_tree(iter
, memcg
) {
2147 if (iter
== failed
) {
2148 mem_cgroup_iter_break(memcg
, iter
);
2151 iter
->oom_lock
= false;
2154 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
2156 spin_unlock(&memcg_oom_lock
);
2161 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
2163 struct mem_cgroup
*iter
;
2165 spin_lock(&memcg_oom_lock
);
2166 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
2167 for_each_mem_cgroup_tree(iter
, memcg
)
2168 iter
->oom_lock
= false;
2169 spin_unlock(&memcg_oom_lock
);
2172 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
2174 struct mem_cgroup
*iter
;
2176 for_each_mem_cgroup_tree(iter
, memcg
)
2177 atomic_inc(&iter
->under_oom
);
2180 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
2182 struct mem_cgroup
*iter
;
2185 * When a new child is created while the hierarchy is under oom,
2186 * mem_cgroup_oom_lock() may not be called. We have to use
2187 * atomic_add_unless() here.
2189 for_each_mem_cgroup_tree(iter
, memcg
)
2190 atomic_add_unless(&iter
->under_oom
, -1, 0);
2193 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
2195 struct oom_wait_info
{
2196 struct mem_cgroup
*memcg
;
2200 static int memcg_oom_wake_function(wait_queue_t
*wait
,
2201 unsigned mode
, int sync
, void *arg
)
2203 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
2204 struct mem_cgroup
*oom_wait_memcg
;
2205 struct oom_wait_info
*oom_wait_info
;
2207 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
2208 oom_wait_memcg
= oom_wait_info
->memcg
;
2211 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
2212 * Then we can use css_is_ancestor without taking care of RCU.
2214 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
2215 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
2217 return autoremove_wake_function(wait
, mode
, sync
, arg
);
2220 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
2222 atomic_inc(&memcg
->oom_wakeups
);
2223 /* for filtering, pass "memcg" as argument. */
2224 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
2227 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
2229 if (memcg
&& atomic_read(&memcg
->under_oom
))
2230 memcg_wakeup_oom(memcg
);
2233 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
2235 if (!current
->memcg_oom
.may_oom
)
2238 * We are in the middle of the charge context here, so we
2239 * don't want to block when potentially sitting on a callstack
2240 * that holds all kinds of filesystem and mm locks.
2242 * Also, the caller may handle a failed allocation gracefully
2243 * (like optional page cache readahead) and so an OOM killer
2244 * invocation might not even be necessary.
2246 * That's why we don't do anything here except remember the
2247 * OOM context and then deal with it at the end of the page
2248 * fault when the stack is unwound, the locks are released,
2249 * and when we know whether the fault was overall successful.
2251 css_get(&memcg
->css
);
2252 current
->memcg_oom
.memcg
= memcg
;
2253 current
->memcg_oom
.gfp_mask
= mask
;
2254 current
->memcg_oom
.order
= order
;
2258 * mem_cgroup_oom_synchronize - complete memcg OOM handling
2259 * @handle: actually kill/wait or just clean up the OOM state
2261 * This has to be called at the end of a page fault if the memcg OOM
2262 * handler was enabled.
2264 * Memcg supports userspace OOM handling where failed allocations must
2265 * sleep on a waitqueue until the userspace task resolves the
2266 * situation. Sleeping directly in the charge context with all kinds
2267 * of locks held is not a good idea, instead we remember an OOM state
2268 * in the task and mem_cgroup_oom_synchronize() has to be called at
2269 * the end of the page fault to complete the OOM handling.
2271 * Returns %true if an ongoing memcg OOM situation was detected and
2272 * completed, %false otherwise.
2274 bool mem_cgroup_oom_synchronize(bool handle
)
2276 struct mem_cgroup
*memcg
= current
->memcg_oom
.memcg
;
2277 struct oom_wait_info owait
;
2280 /* OOM is global, do not handle */
2287 owait
.memcg
= memcg
;
2288 owait
.wait
.flags
= 0;
2289 owait
.wait
.func
= memcg_oom_wake_function
;
2290 owait
.wait
.private = current
;
2291 INIT_LIST_HEAD(&owait
.wait
.task_list
);
2293 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
2294 mem_cgroup_mark_under_oom(memcg
);
2296 locked
= mem_cgroup_oom_trylock(memcg
);
2299 mem_cgroup_oom_notify(memcg
);
2301 if (locked
&& !memcg
->oom_kill_disable
) {
2302 mem_cgroup_unmark_under_oom(memcg
);
2303 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2304 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom
.gfp_mask
,
2305 current
->memcg_oom
.order
);
2308 mem_cgroup_unmark_under_oom(memcg
);
2309 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
2313 mem_cgroup_oom_unlock(memcg
);
2315 * There is no guarantee that an OOM-lock contender
2316 * sees the wakeups triggered by the OOM kill
2317 * uncharges. Wake any sleepers explicitely.
2319 memcg_oom_recover(memcg
);
2322 current
->memcg_oom
.memcg
= NULL
;
2323 css_put(&memcg
->css
);
2328 * Currently used to update mapped file statistics, but the routine can be
2329 * generalized to update other statistics as well.
2331 * Notes: Race condition
2333 * We usually use page_cgroup_lock() for accessing page_cgroup member but
2334 * it tends to be costly. But considering some conditions, we doesn't need
2335 * to do so _always_.
2337 * Considering "charge", lock_page_cgroup() is not required because all
2338 * file-stat operations happen after a page is attached to radix-tree. There
2339 * are no race with "charge".
2341 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
2342 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
2343 * if there are race with "uncharge". Statistics itself is properly handled
2346 * Considering "move", this is an only case we see a race. To make the race
2347 * small, we check mm->moving_account and detect there are possibility of race
2348 * If there is, we take a lock.
2351 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
2352 bool *locked
, unsigned long *flags
)
2354 struct mem_cgroup
*memcg
;
2355 struct page_cgroup
*pc
;
2357 pc
= lookup_page_cgroup(page
);
2359 memcg
= pc
->mem_cgroup
;
2360 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2363 * If this memory cgroup is not under account moving, we don't
2364 * need to take move_lock_mem_cgroup(). Because we already hold
2365 * rcu_read_lock(), any calls to move_account will be delayed until
2366 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2368 if (!mem_cgroup_stolen(memcg
))
2371 move_lock_mem_cgroup(memcg
, flags
);
2372 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2373 move_unlock_mem_cgroup(memcg
, flags
);
2379 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2381 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2384 * It's guaranteed that pc->mem_cgroup never changes while
2385 * lock is held because a routine modifies pc->mem_cgroup
2386 * should take move_lock_mem_cgroup().
2388 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2391 void mem_cgroup_update_page_stat(struct page
*page
,
2392 enum mem_cgroup_stat_index idx
, int val
)
2394 struct mem_cgroup
*memcg
;
2395 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2396 unsigned long uninitialized_var(flags
);
2398 if (mem_cgroup_disabled())
2401 VM_BUG_ON(!rcu_read_lock_held());
2402 memcg
= pc
->mem_cgroup
;
2403 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2406 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2410 * size of first charge trial. "32" comes from vmscan.c's magic value.
2411 * TODO: maybe necessary to use big numbers in big irons.
2413 #define CHARGE_BATCH 32U
2414 struct memcg_stock_pcp
{
2415 struct mem_cgroup
*cached
; /* this never be root cgroup */
2416 unsigned int nr_pages
;
2417 struct work_struct work
;
2418 unsigned long flags
;
2419 #define FLUSHING_CACHED_CHARGE 0
2421 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2422 static DEFINE_MUTEX(percpu_charge_mutex
);
2425 * consume_stock: Try to consume stocked charge on this cpu.
2426 * @memcg: memcg to consume from.
2427 * @nr_pages: how many pages to charge.
2429 * The charges will only happen if @memcg matches the current cpu's memcg
2430 * stock, and at least @nr_pages are available in that stock. Failure to
2431 * service an allocation will refill the stock.
2433 * returns true if successful, false otherwise.
2435 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2437 struct memcg_stock_pcp
*stock
;
2440 if (nr_pages
> CHARGE_BATCH
)
2443 stock
= &get_cpu_var(memcg_stock
);
2444 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
)
2445 stock
->nr_pages
-= nr_pages
;
2446 else /* need to call res_counter_charge */
2448 put_cpu_var(memcg_stock
);
2453 * Returns stocks cached in percpu to res_counter and reset cached information.
2455 static void drain_stock(struct memcg_stock_pcp
*stock
)
2457 struct mem_cgroup
*old
= stock
->cached
;
2459 if (stock
->nr_pages
) {
2460 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2462 res_counter_uncharge(&old
->res
, bytes
);
2463 if (do_swap_account
)
2464 res_counter_uncharge(&old
->memsw
, bytes
);
2465 stock
->nr_pages
= 0;
2467 stock
->cached
= NULL
;
2471 * This must be called under preempt disabled or must be called by
2472 * a thread which is pinned to local cpu.
2474 static void drain_local_stock(struct work_struct
*dummy
)
2476 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2478 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2481 static void __init
memcg_stock_init(void)
2485 for_each_possible_cpu(cpu
) {
2486 struct memcg_stock_pcp
*stock
=
2487 &per_cpu(memcg_stock
, cpu
);
2488 INIT_WORK(&stock
->work
, drain_local_stock
);
2493 * Cache charges(val) which is from res_counter, to local per_cpu area.
2494 * This will be consumed by consume_stock() function, later.
2496 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2498 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2500 if (stock
->cached
!= memcg
) { /* reset if necessary */
2502 stock
->cached
= memcg
;
2504 stock
->nr_pages
+= nr_pages
;
2505 put_cpu_var(memcg_stock
);
2509 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2510 * of the hierarchy under it. sync flag says whether we should block
2511 * until the work is done.
2513 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2517 /* Notify other cpus that system-wide "drain" is running */
2520 for_each_online_cpu(cpu
) {
2521 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2522 struct mem_cgroup
*memcg
;
2524 memcg
= stock
->cached
;
2525 if (!memcg
|| !stock
->nr_pages
)
2527 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2529 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2531 drain_local_stock(&stock
->work
);
2533 schedule_work_on(cpu
, &stock
->work
);
2541 for_each_online_cpu(cpu
) {
2542 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2543 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2544 flush_work(&stock
->work
);
2551 * Tries to drain stocked charges in other cpus. This function is asynchronous
2552 * and just put a work per cpu for draining localy on each cpu. Caller can
2553 * expects some charges will be back to res_counter later but cannot wait for
2556 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2559 * If someone calls draining, avoid adding more kworker runs.
2561 if (!mutex_trylock(&percpu_charge_mutex
))
2563 drain_all_stock(root_memcg
, false);
2564 mutex_unlock(&percpu_charge_mutex
);
2567 /* This is a synchronous drain interface. */
2568 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2570 /* called when force_empty is called */
2571 mutex_lock(&percpu_charge_mutex
);
2572 drain_all_stock(root_memcg
, true);
2573 mutex_unlock(&percpu_charge_mutex
);
2577 * This function drains percpu counter value from DEAD cpu and
2578 * move it to local cpu. Note that this function can be preempted.
2580 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2584 spin_lock(&memcg
->pcp_counter_lock
);
2585 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2586 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2588 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2589 memcg
->nocpu_base
.count
[i
] += x
;
2591 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2592 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2594 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2595 memcg
->nocpu_base
.events
[i
] += x
;
2597 spin_unlock(&memcg
->pcp_counter_lock
);
2600 static int memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2601 unsigned long action
,
2604 int cpu
= (unsigned long)hcpu
;
2605 struct memcg_stock_pcp
*stock
;
2606 struct mem_cgroup
*iter
;
2608 if (action
== CPU_ONLINE
)
2611 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2614 for_each_mem_cgroup(iter
)
2615 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2617 stock
= &per_cpu(memcg_stock
, cpu
);
2623 /* See __mem_cgroup_try_charge() for details */
2625 CHARGE_OK
, /* success */
2626 CHARGE_RETRY
, /* need to retry but retry is not bad */
2627 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2628 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2631 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2632 unsigned int nr_pages
, unsigned int min_pages
,
2635 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2636 struct mem_cgroup
*mem_over_limit
;
2637 struct res_counter
*fail_res
;
2638 unsigned long flags
= 0;
2641 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2644 if (!do_swap_account
)
2646 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2650 res_counter_uncharge(&memcg
->res
, csize
);
2651 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2652 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2654 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2656 * Never reclaim on behalf of optional batching, retry with a
2657 * single page instead.
2659 if (nr_pages
> min_pages
)
2660 return CHARGE_RETRY
;
2662 if (!(gfp_mask
& __GFP_WAIT
))
2663 return CHARGE_WOULDBLOCK
;
2665 if (gfp_mask
& __GFP_NORETRY
)
2666 return CHARGE_NOMEM
;
2668 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2669 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2670 return CHARGE_RETRY
;
2672 * Even though the limit is exceeded at this point, reclaim
2673 * may have been able to free some pages. Retry the charge
2674 * before killing the task.
2676 * Only for regular pages, though: huge pages are rather
2677 * unlikely to succeed so close to the limit, and we fall back
2678 * to regular pages anyway in case of failure.
2680 if (nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
) && ret
)
2681 return CHARGE_RETRY
;
2684 * At task move, charge accounts can be doubly counted. So, it's
2685 * better to wait until the end of task_move if something is going on.
2687 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2688 return CHARGE_RETRY
;
2691 mem_cgroup_oom(mem_over_limit
, gfp_mask
, get_order(csize
));
2693 return CHARGE_NOMEM
;
2697 * __mem_cgroup_try_charge() does
2698 * 1. detect memcg to be charged against from passed *mm and *ptr,
2699 * 2. update res_counter
2700 * 3. call memory reclaim if necessary.
2702 * In some special case, if the task is fatal, fatal_signal_pending() or
2703 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2704 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2705 * as possible without any hazards. 2: all pages should have a valid
2706 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2707 * pointer, that is treated as a charge to root_mem_cgroup.
2709 * So __mem_cgroup_try_charge() will return
2710 * 0 ... on success, filling *ptr with a valid memcg pointer.
2711 * -ENOMEM ... charge failure because of resource limits.
2712 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2714 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2715 * the oom-killer can be invoked.
2717 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2719 unsigned int nr_pages
,
2720 struct mem_cgroup
**ptr
,
2723 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2724 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2725 struct mem_cgroup
*memcg
= NULL
;
2729 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2730 * in system level. So, allow to go ahead dying process in addition to
2733 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2734 || fatal_signal_pending(current
)))
2737 if (unlikely(task_in_memcg_oom(current
)))
2741 * We always charge the cgroup the mm_struct belongs to.
2742 * The mm_struct's mem_cgroup changes on task migration if the
2743 * thread group leader migrates. It's possible that mm is not
2744 * set, if so charge the root memcg (happens for pagecache usage).
2747 *ptr
= root_mem_cgroup
;
2749 if (*ptr
) { /* css should be a valid one */
2751 if (mem_cgroup_is_root(memcg
))
2753 if (consume_stock(memcg
, nr_pages
))
2755 css_get(&memcg
->css
);
2757 struct task_struct
*p
;
2760 p
= rcu_dereference(mm
->owner
);
2762 * Because we don't have task_lock(), "p" can exit.
2763 * In that case, "memcg" can point to root or p can be NULL with
2764 * race with swapoff. Then, we have small risk of mis-accouning.
2765 * But such kind of mis-account by race always happens because
2766 * we don't have cgroup_mutex(). It's overkill and we allo that
2768 * (*) swapoff at el will charge against mm-struct not against
2769 * task-struct. So, mm->owner can be NULL.
2771 memcg
= mem_cgroup_from_task(p
);
2773 memcg
= root_mem_cgroup
;
2774 if (mem_cgroup_is_root(memcg
)) {
2778 if (consume_stock(memcg
, nr_pages
)) {
2780 * It seems dagerous to access memcg without css_get().
2781 * But considering how consume_stok works, it's not
2782 * necessary. If consume_stock success, some charges
2783 * from this memcg are cached on this cpu. So, we
2784 * don't need to call css_get()/css_tryget() before
2785 * calling consume_stock().
2790 /* after here, we may be blocked. we need to get refcnt */
2791 if (!css_tryget(&memcg
->css
)) {
2799 bool invoke_oom
= oom
&& !nr_oom_retries
;
2801 /* If killed, bypass charge */
2802 if (fatal_signal_pending(current
)) {
2803 css_put(&memcg
->css
);
2807 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
,
2808 nr_pages
, invoke_oom
);
2812 case CHARGE_RETRY
: /* not in OOM situation but retry */
2814 css_put(&memcg
->css
);
2817 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2818 css_put(&memcg
->css
);
2820 case CHARGE_NOMEM
: /* OOM routine works */
2821 if (!oom
|| invoke_oom
) {
2822 css_put(&memcg
->css
);
2828 } while (ret
!= CHARGE_OK
);
2830 if (batch
> nr_pages
)
2831 refill_stock(memcg
, batch
- nr_pages
);
2832 css_put(&memcg
->css
);
2837 if (!(gfp_mask
& __GFP_NOFAIL
)) {
2842 *ptr
= root_mem_cgroup
;
2847 * Somemtimes we have to undo a charge we got by try_charge().
2848 * This function is for that and do uncharge, put css's refcnt.
2849 * gotten by try_charge().
2851 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2852 unsigned int nr_pages
)
2854 if (!mem_cgroup_is_root(memcg
)) {
2855 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2857 res_counter_uncharge(&memcg
->res
, bytes
);
2858 if (do_swap_account
)
2859 res_counter_uncharge(&memcg
->memsw
, bytes
);
2864 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2865 * This is useful when moving usage to parent cgroup.
2867 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2868 unsigned int nr_pages
)
2870 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2872 if (mem_cgroup_is_root(memcg
))
2875 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2876 if (do_swap_account
)
2877 res_counter_uncharge_until(&memcg
->memsw
,
2878 memcg
->memsw
.parent
, bytes
);
2882 * A helper function to get mem_cgroup from ID. must be called under
2883 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2884 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2885 * called against removed memcg.)
2887 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2889 /* ID 0 is unused ID */
2892 return mem_cgroup_from_id(id
);
2895 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2897 struct mem_cgroup
*memcg
= NULL
;
2898 struct page_cgroup
*pc
;
2902 VM_BUG_ON(!PageLocked(page
));
2904 pc
= lookup_page_cgroup(page
);
2905 lock_page_cgroup(pc
);
2906 if (PageCgroupUsed(pc
)) {
2907 memcg
= pc
->mem_cgroup
;
2908 if (memcg
&& !css_tryget(&memcg
->css
))
2910 } else if (PageSwapCache(page
)) {
2911 ent
.val
= page_private(page
);
2912 id
= lookup_swap_cgroup_id(ent
);
2914 memcg
= mem_cgroup_lookup(id
);
2915 if (memcg
&& !css_tryget(&memcg
->css
))
2919 unlock_page_cgroup(pc
);
2923 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2925 unsigned int nr_pages
,
2926 enum charge_type ctype
,
2929 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2930 struct zone
*uninitialized_var(zone
);
2931 struct lruvec
*lruvec
;
2932 bool was_on_lru
= false;
2935 lock_page_cgroup(pc
);
2936 VM_BUG_ON(PageCgroupUsed(pc
));
2938 * we don't need page_cgroup_lock about tail pages, becase they are not
2939 * accessed by any other context at this point.
2943 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2944 * may already be on some other mem_cgroup's LRU. Take care of it.
2947 zone
= page_zone(page
);
2948 spin_lock_irq(&zone
->lru_lock
);
2949 if (PageLRU(page
)) {
2950 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2952 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2957 pc
->mem_cgroup
= memcg
;
2959 * We access a page_cgroup asynchronously without lock_page_cgroup().
2960 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2961 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2962 * before USED bit, we need memory barrier here.
2963 * See mem_cgroup_add_lru_list(), etc.
2966 SetPageCgroupUsed(pc
);
2970 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2971 VM_BUG_ON(PageLRU(page
));
2973 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2975 spin_unlock_irq(&zone
->lru_lock
);
2978 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2983 mem_cgroup_charge_statistics(memcg
, page
, anon
, nr_pages
);
2984 unlock_page_cgroup(pc
);
2987 * "charge_statistics" updated event counter. Then, check it.
2988 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2989 * if they exceeds softlimit.
2991 memcg_check_events(memcg
, page
);
2994 static DEFINE_MUTEX(set_limit_mutex
);
2996 #ifdef CONFIG_MEMCG_KMEM
2997 static inline bool memcg_can_account_kmem(struct mem_cgroup
*memcg
)
2999 return !mem_cgroup_disabled() && !mem_cgroup_is_root(memcg
) &&
3000 (memcg
->kmem_account_flags
& KMEM_ACCOUNTED_MASK
);
3004 * This is a bit cumbersome, but it is rarely used and avoids a backpointer
3005 * in the memcg_cache_params struct.
3007 static struct kmem_cache
*memcg_params_to_cache(struct memcg_cache_params
*p
)
3009 struct kmem_cache
*cachep
;
3011 VM_BUG_ON(p
->is_root_cache
);
3012 cachep
= p
->root_cache
;
3013 return cache_from_memcg_idx(cachep
, memcg_cache_id(p
->memcg
));
3016 #ifdef CONFIG_SLABINFO
3017 static int mem_cgroup_slabinfo_read(struct seq_file
*m
, void *v
)
3019 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3020 struct memcg_cache_params
*params
;
3022 if (!memcg_can_account_kmem(memcg
))
3025 print_slabinfo_header(m
);
3027 mutex_lock(&memcg
->slab_caches_mutex
);
3028 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
)
3029 cache_show(memcg_params_to_cache(params
), m
);
3030 mutex_unlock(&memcg
->slab_caches_mutex
);
3036 static int memcg_charge_kmem(struct mem_cgroup
*memcg
, gfp_t gfp
, u64 size
)
3038 struct res_counter
*fail_res
;
3039 struct mem_cgroup
*_memcg
;
3042 ret
= res_counter_charge(&memcg
->kmem
, size
, &fail_res
);
3047 ret
= __mem_cgroup_try_charge(NULL
, gfp
, size
>> PAGE_SHIFT
,
3048 &_memcg
, oom_gfp_allowed(gfp
));
3050 if (ret
== -EINTR
) {
3052 * __mem_cgroup_try_charge() chosed to bypass to root due to
3053 * OOM kill or fatal signal. Since our only options are to
3054 * either fail the allocation or charge it to this cgroup, do
3055 * it as a temporary condition. But we can't fail. From a
3056 * kmem/slab perspective, the cache has already been selected,
3057 * by mem_cgroup_kmem_get_cache(), so it is too late to change
3060 * This condition will only trigger if the task entered
3061 * memcg_charge_kmem in a sane state, but was OOM-killed during
3062 * __mem_cgroup_try_charge() above. Tasks that were already
3063 * dying when the allocation triggers should have been already
3064 * directed to the root cgroup in memcontrol.h
3066 res_counter_charge_nofail(&memcg
->res
, size
, &fail_res
);
3067 if (do_swap_account
)
3068 res_counter_charge_nofail(&memcg
->memsw
, size
,
3072 res_counter_uncharge(&memcg
->kmem
, size
);
3077 static void memcg_uncharge_kmem(struct mem_cgroup
*memcg
, u64 size
)
3079 res_counter_uncharge(&memcg
->res
, size
);
3080 if (do_swap_account
)
3081 res_counter_uncharge(&memcg
->memsw
, size
);
3084 if (res_counter_uncharge(&memcg
->kmem
, size
))
3088 * Releases a reference taken in kmem_cgroup_css_offline in case
3089 * this last uncharge is racing with the offlining code or it is
3090 * outliving the memcg existence.
3092 * The memory barrier imposed by test&clear is paired with the
3093 * explicit one in memcg_kmem_mark_dead().
3095 if (memcg_kmem_test_and_clear_dead(memcg
))
3096 css_put(&memcg
->css
);
3099 void memcg_cache_list_add(struct mem_cgroup
*memcg
, struct kmem_cache
*cachep
)
3104 mutex_lock(&memcg
->slab_caches_mutex
);
3105 list_add(&cachep
->memcg_params
->list
, &memcg
->memcg_slab_caches
);
3106 mutex_unlock(&memcg
->slab_caches_mutex
);
3110 * helper for acessing a memcg's index. It will be used as an index in the
3111 * child cache array in kmem_cache, and also to derive its name. This function
3112 * will return -1 when this is not a kmem-limited memcg.
3114 int memcg_cache_id(struct mem_cgroup
*memcg
)
3116 return memcg
? memcg
->kmemcg_id
: -1;
3120 * This ends up being protected by the set_limit mutex, during normal
3121 * operation, because that is its main call site.
3123 * But when we create a new cache, we can call this as well if its parent
3124 * is kmem-limited. That will have to hold set_limit_mutex as well.
3126 int memcg_update_cache_sizes(struct mem_cgroup
*memcg
)
3130 num
= ida_simple_get(&kmem_limited_groups
,
3131 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
3135 * After this point, kmem_accounted (that we test atomically in
3136 * the beginning of this conditional), is no longer 0. This
3137 * guarantees only one process will set the following boolean
3138 * to true. We don't need test_and_set because we're protected
3139 * by the set_limit_mutex anyway.
3141 memcg_kmem_set_activated(memcg
);
3143 ret
= memcg_update_all_caches(num
+1);
3145 ida_simple_remove(&kmem_limited_groups
, num
);
3146 memcg_kmem_clear_activated(memcg
);
3150 memcg
->kmemcg_id
= num
;
3151 INIT_LIST_HEAD(&memcg
->memcg_slab_caches
);
3152 mutex_init(&memcg
->slab_caches_mutex
);
3156 static size_t memcg_caches_array_size(int num_groups
)
3159 if (num_groups
<= 0)
3162 size
= 2 * num_groups
;
3163 if (size
< MEMCG_CACHES_MIN_SIZE
)
3164 size
= MEMCG_CACHES_MIN_SIZE
;
3165 else if (size
> MEMCG_CACHES_MAX_SIZE
)
3166 size
= MEMCG_CACHES_MAX_SIZE
;
3172 * We should update the current array size iff all caches updates succeed. This
3173 * can only be done from the slab side. The slab mutex needs to be held when
3176 void memcg_update_array_size(int num
)
3178 if (num
> memcg_limited_groups_array_size
)
3179 memcg_limited_groups_array_size
= memcg_caches_array_size(num
);
3182 static void kmem_cache_destroy_work_func(struct work_struct
*w
);
3184 int memcg_update_cache_size(struct kmem_cache
*s
, int num_groups
)
3186 struct memcg_cache_params
*cur_params
= s
->memcg_params
;
3188 VM_BUG_ON(!is_root_cache(s
));
3190 if (num_groups
> memcg_limited_groups_array_size
) {
3192 ssize_t size
= memcg_caches_array_size(num_groups
);
3194 size
*= sizeof(void *);
3195 size
+= offsetof(struct memcg_cache_params
, memcg_caches
);
3197 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3198 if (!s
->memcg_params
) {
3199 s
->memcg_params
= cur_params
;
3203 s
->memcg_params
->is_root_cache
= true;
3206 * There is the chance it will be bigger than
3207 * memcg_limited_groups_array_size, if we failed an allocation
3208 * in a cache, in which case all caches updated before it, will
3209 * have a bigger array.
3211 * But if that is the case, the data after
3212 * memcg_limited_groups_array_size is certainly unused
3214 for (i
= 0; i
< memcg_limited_groups_array_size
; i
++) {
3215 if (!cur_params
->memcg_caches
[i
])
3217 s
->memcg_params
->memcg_caches
[i
] =
3218 cur_params
->memcg_caches
[i
];
3222 * Ideally, we would wait until all caches succeed, and only
3223 * then free the old one. But this is not worth the extra
3224 * pointer per-cache we'd have to have for this.
3226 * It is not a big deal if some caches are left with a size
3227 * bigger than the others. And all updates will reset this
3235 int memcg_register_cache(struct mem_cgroup
*memcg
, struct kmem_cache
*s
,
3236 struct kmem_cache
*root_cache
)
3240 if (!memcg_kmem_enabled())
3244 size
= offsetof(struct memcg_cache_params
, memcg_caches
);
3245 size
+= memcg_limited_groups_array_size
* sizeof(void *);
3247 size
= sizeof(struct memcg_cache_params
);
3249 s
->memcg_params
= kzalloc(size
, GFP_KERNEL
);
3250 if (!s
->memcg_params
)
3254 s
->memcg_params
->memcg
= memcg
;
3255 s
->memcg_params
->root_cache
= root_cache
;
3256 INIT_WORK(&s
->memcg_params
->destroy
,
3257 kmem_cache_destroy_work_func
);
3259 s
->memcg_params
->is_root_cache
= true;
3264 void memcg_release_cache(struct kmem_cache
*s
)
3266 struct kmem_cache
*root
;
3267 struct mem_cgroup
*memcg
;
3271 * This happens, for instance, when a root cache goes away before we
3274 if (!s
->memcg_params
)
3277 if (s
->memcg_params
->is_root_cache
)
3280 memcg
= s
->memcg_params
->memcg
;
3281 id
= memcg_cache_id(memcg
);
3283 root
= s
->memcg_params
->root_cache
;
3284 root
->memcg_params
->memcg_caches
[id
] = NULL
;
3286 mutex_lock(&memcg
->slab_caches_mutex
);
3287 list_del(&s
->memcg_params
->list
);
3288 mutex_unlock(&memcg
->slab_caches_mutex
);
3290 css_put(&memcg
->css
);
3292 kfree(s
->memcg_params
);
3296 * During the creation a new cache, we need to disable our accounting mechanism
3297 * altogether. This is true even if we are not creating, but rather just
3298 * enqueing new caches to be created.
3300 * This is because that process will trigger allocations; some visible, like
3301 * explicit kmallocs to auxiliary data structures, name strings and internal
3302 * cache structures; some well concealed, like INIT_WORK() that can allocate
3303 * objects during debug.
3305 * If any allocation happens during memcg_kmem_get_cache, we will recurse back
3306 * to it. This may not be a bounded recursion: since the first cache creation
3307 * failed to complete (waiting on the allocation), we'll just try to create the
3308 * cache again, failing at the same point.
3310 * memcg_kmem_get_cache is prepared to abort after seeing a positive count of
3311 * memcg_kmem_skip_account. So we enclose anything that might allocate memory
3312 * inside the following two functions.
3314 static inline void memcg_stop_kmem_account(void)
3316 VM_BUG_ON(!current
->mm
);
3317 current
->memcg_kmem_skip_account
++;
3320 static inline void memcg_resume_kmem_account(void)
3322 VM_BUG_ON(!current
->mm
);
3323 current
->memcg_kmem_skip_account
--;
3326 static void kmem_cache_destroy_work_func(struct work_struct
*w
)
3328 struct kmem_cache
*cachep
;
3329 struct memcg_cache_params
*p
;
3331 p
= container_of(w
, struct memcg_cache_params
, destroy
);
3333 cachep
= memcg_params_to_cache(p
);
3336 * If we get down to 0 after shrink, we could delete right away.
3337 * However, memcg_release_pages() already puts us back in the workqueue
3338 * in that case. If we proceed deleting, we'll get a dangling
3339 * reference, and removing the object from the workqueue in that case
3340 * is unnecessary complication. We are not a fast path.
3342 * Note that this case is fundamentally different from racing with
3343 * shrink_slab(): if memcg_cgroup_destroy_cache() is called in
3344 * kmem_cache_shrink, not only we would be reinserting a dead cache
3345 * into the queue, but doing so from inside the worker racing to
3348 * So if we aren't down to zero, we'll just schedule a worker and try
3351 if (atomic_read(&cachep
->memcg_params
->nr_pages
) != 0) {
3352 kmem_cache_shrink(cachep
);
3353 if (atomic_read(&cachep
->memcg_params
->nr_pages
) == 0)
3356 kmem_cache_destroy(cachep
);
3359 void mem_cgroup_destroy_cache(struct kmem_cache
*cachep
)
3361 if (!cachep
->memcg_params
->dead
)
3365 * There are many ways in which we can get here.
3367 * We can get to a memory-pressure situation while the delayed work is
3368 * still pending to run. The vmscan shrinkers can then release all
3369 * cache memory and get us to destruction. If this is the case, we'll
3370 * be executed twice, which is a bug (the second time will execute over
3371 * bogus data). In this case, cancelling the work should be fine.
3373 * But we can also get here from the worker itself, if
3374 * kmem_cache_shrink is enough to shake all the remaining objects and
3375 * get the page count to 0. In this case, we'll deadlock if we try to
3376 * cancel the work (the worker runs with an internal lock held, which
3377 * is the same lock we would hold for cancel_work_sync().)
3379 * Since we can't possibly know who got us here, just refrain from
3380 * running if there is already work pending
3382 if (work_pending(&cachep
->memcg_params
->destroy
))
3385 * We have to defer the actual destroying to a workqueue, because
3386 * we might currently be in a context that cannot sleep.
3388 schedule_work(&cachep
->memcg_params
->destroy
);
3392 * This lock protects updaters, not readers. We want readers to be as fast as
3393 * they can, and they will either see NULL or a valid cache value. Our model
3394 * allow them to see NULL, in which case the root memcg will be selected.
3396 * We need this lock because multiple allocations to the same cache from a non
3397 * will span more than one worker. Only one of them can create the cache.
3399 static DEFINE_MUTEX(memcg_cache_mutex
);
3402 * Called with memcg_cache_mutex held
3404 static struct kmem_cache
*kmem_cache_dup(struct mem_cgroup
*memcg
,
3405 struct kmem_cache
*s
)
3407 struct kmem_cache
*new;
3408 static char *tmp_name
= NULL
;
3410 lockdep_assert_held(&memcg_cache_mutex
);
3413 * kmem_cache_create_memcg duplicates the given name and
3414 * cgroup_name for this name requires RCU context.
3415 * This static temporary buffer is used to prevent from
3416 * pointless shortliving allocation.
3419 tmp_name
= kmalloc(PATH_MAX
, GFP_KERNEL
);
3425 snprintf(tmp_name
, PATH_MAX
, "%s(%d:%s)", s
->name
,
3426 memcg_cache_id(memcg
), cgroup_name(memcg
->css
.cgroup
));
3429 new = kmem_cache_create_memcg(memcg
, tmp_name
, s
->object_size
, s
->align
,
3430 (s
->flags
& ~SLAB_PANIC
), s
->ctor
, s
);
3433 new->allocflags
|= __GFP_KMEMCG
;
3438 static struct kmem_cache
*memcg_create_kmem_cache(struct mem_cgroup
*memcg
,
3439 struct kmem_cache
*cachep
)
3441 struct kmem_cache
*new_cachep
;
3444 BUG_ON(!memcg_can_account_kmem(memcg
));
3446 idx
= memcg_cache_id(memcg
);
3448 mutex_lock(&memcg_cache_mutex
);
3449 new_cachep
= cache_from_memcg_idx(cachep
, idx
);
3451 css_put(&memcg
->css
);
3455 new_cachep
= kmem_cache_dup(memcg
, cachep
);
3456 if (new_cachep
== NULL
) {
3457 new_cachep
= cachep
;
3458 css_put(&memcg
->css
);
3462 atomic_set(&new_cachep
->memcg_params
->nr_pages
, 0);
3464 cachep
->memcg_params
->memcg_caches
[idx
] = new_cachep
;
3466 * the readers won't lock, make sure everybody sees the updated value,
3467 * so they won't put stuff in the queue again for no reason
3471 mutex_unlock(&memcg_cache_mutex
);
3475 void kmem_cache_destroy_memcg_children(struct kmem_cache
*s
)
3477 struct kmem_cache
*c
;
3480 if (!s
->memcg_params
)
3482 if (!s
->memcg_params
->is_root_cache
)
3486 * If the cache is being destroyed, we trust that there is no one else
3487 * requesting objects from it. Even if there are, the sanity checks in
3488 * kmem_cache_destroy should caught this ill-case.
3490 * Still, we don't want anyone else freeing memcg_caches under our
3491 * noses, which can happen if a new memcg comes to life. As usual,
3492 * we'll take the set_limit_mutex to protect ourselves against this.
3494 mutex_lock(&set_limit_mutex
);
3495 for_each_memcg_cache_index(i
) {
3496 c
= cache_from_memcg_idx(s
, i
);
3501 * We will now manually delete the caches, so to avoid races
3502 * we need to cancel all pending destruction workers and
3503 * proceed with destruction ourselves.
3505 * kmem_cache_destroy() will call kmem_cache_shrink internally,
3506 * and that could spawn the workers again: it is likely that
3507 * the cache still have active pages until this very moment.
3508 * This would lead us back to mem_cgroup_destroy_cache.
3510 * But that will not execute at all if the "dead" flag is not
3511 * set, so flip it down to guarantee we are in control.
3513 c
->memcg_params
->dead
= false;
3514 cancel_work_sync(&c
->memcg_params
->destroy
);
3515 kmem_cache_destroy(c
);
3517 mutex_unlock(&set_limit_mutex
);
3520 struct create_work
{
3521 struct mem_cgroup
*memcg
;
3522 struct kmem_cache
*cachep
;
3523 struct work_struct work
;
3526 static void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3528 struct kmem_cache
*cachep
;
3529 struct memcg_cache_params
*params
;
3531 if (!memcg_kmem_is_active(memcg
))
3534 mutex_lock(&memcg
->slab_caches_mutex
);
3535 list_for_each_entry(params
, &memcg
->memcg_slab_caches
, list
) {
3536 cachep
= memcg_params_to_cache(params
);
3537 cachep
->memcg_params
->dead
= true;
3538 schedule_work(&cachep
->memcg_params
->destroy
);
3540 mutex_unlock(&memcg
->slab_caches_mutex
);
3543 static void memcg_create_cache_work_func(struct work_struct
*w
)
3545 struct create_work
*cw
;
3547 cw
= container_of(w
, struct create_work
, work
);
3548 memcg_create_kmem_cache(cw
->memcg
, cw
->cachep
);
3553 * Enqueue the creation of a per-memcg kmem_cache.
3555 static void __memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3556 struct kmem_cache
*cachep
)
3558 struct create_work
*cw
;
3560 cw
= kmalloc(sizeof(struct create_work
), GFP_NOWAIT
);
3562 css_put(&memcg
->css
);
3567 cw
->cachep
= cachep
;
3569 INIT_WORK(&cw
->work
, memcg_create_cache_work_func
);
3570 schedule_work(&cw
->work
);
3573 static void memcg_create_cache_enqueue(struct mem_cgroup
*memcg
,
3574 struct kmem_cache
*cachep
)
3577 * We need to stop accounting when we kmalloc, because if the
3578 * corresponding kmalloc cache is not yet created, the first allocation
3579 * in __memcg_create_cache_enqueue will recurse.
3581 * However, it is better to enclose the whole function. Depending on
3582 * the debugging options enabled, INIT_WORK(), for instance, can
3583 * trigger an allocation. This too, will make us recurse. Because at
3584 * this point we can't allow ourselves back into memcg_kmem_get_cache,
3585 * the safest choice is to do it like this, wrapping the whole function.
3587 memcg_stop_kmem_account();
3588 __memcg_create_cache_enqueue(memcg
, cachep
);
3589 memcg_resume_kmem_account();
3592 * Return the kmem_cache we're supposed to use for a slab allocation.
3593 * We try to use the current memcg's version of the cache.
3595 * If the cache does not exist yet, if we are the first user of it,
3596 * we either create it immediately, if possible, or create it asynchronously
3598 * In the latter case, we will let the current allocation go through with
3599 * the original cache.
3601 * Can't be called in interrupt context or from kernel threads.
3602 * This function needs to be called with rcu_read_lock() held.
3604 struct kmem_cache
*__memcg_kmem_get_cache(struct kmem_cache
*cachep
,
3607 struct mem_cgroup
*memcg
;
3610 VM_BUG_ON(!cachep
->memcg_params
);
3611 VM_BUG_ON(!cachep
->memcg_params
->is_root_cache
);
3613 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3617 memcg
= mem_cgroup_from_task(rcu_dereference(current
->mm
->owner
));
3619 if (!memcg_can_account_kmem(memcg
))
3622 idx
= memcg_cache_id(memcg
);
3625 * barrier to mare sure we're always seeing the up to date value. The
3626 * code updating memcg_caches will issue a write barrier to match this.
3628 read_barrier_depends();
3629 if (likely(cache_from_memcg_idx(cachep
, idx
))) {
3630 cachep
= cache_from_memcg_idx(cachep
, idx
);
3634 /* The corresponding put will be done in the workqueue. */
3635 if (!css_tryget(&memcg
->css
))
3640 * If we are in a safe context (can wait, and not in interrupt
3641 * context), we could be be predictable and return right away.
3642 * This would guarantee that the allocation being performed
3643 * already belongs in the new cache.
3645 * However, there are some clashes that can arrive from locking.
3646 * For instance, because we acquire the slab_mutex while doing
3647 * kmem_cache_dup, this means no further allocation could happen
3648 * with the slab_mutex held.
3650 * Also, because cache creation issue get_online_cpus(), this
3651 * creates a lock chain: memcg_slab_mutex -> cpu_hotplug_mutex,
3652 * that ends up reversed during cpu hotplug. (cpuset allocates
3653 * a bunch of GFP_KERNEL memory during cpuup). Due to all that,
3654 * better to defer everything.
3656 memcg_create_cache_enqueue(memcg
, cachep
);
3662 EXPORT_SYMBOL(__memcg_kmem_get_cache
);
3665 * We need to verify if the allocation against current->mm->owner's memcg is
3666 * possible for the given order. But the page is not allocated yet, so we'll
3667 * need a further commit step to do the final arrangements.
3669 * It is possible for the task to switch cgroups in this mean time, so at
3670 * commit time, we can't rely on task conversion any longer. We'll then use
3671 * the handle argument to return to the caller which cgroup we should commit
3672 * against. We could also return the memcg directly and avoid the pointer
3673 * passing, but a boolean return value gives better semantics considering
3674 * the compiled-out case as well.
3676 * Returning true means the allocation is possible.
3679 __memcg_kmem_newpage_charge(gfp_t gfp
, struct mem_cgroup
**_memcg
, int order
)
3681 struct mem_cgroup
*memcg
;
3687 * Disabling accounting is only relevant for some specific memcg
3688 * internal allocations. Therefore we would initially not have such
3689 * check here, since direct calls to the page allocator that are marked
3690 * with GFP_KMEMCG only happen outside memcg core. We are mostly
3691 * concerned with cache allocations, and by having this test at
3692 * memcg_kmem_get_cache, we are already able to relay the allocation to
3693 * the root cache and bypass the memcg cache altogether.
3695 * There is one exception, though: the SLUB allocator does not create
3696 * large order caches, but rather service large kmallocs directly from
3697 * the page allocator. Therefore, the following sequence when backed by
3698 * the SLUB allocator:
3700 * memcg_stop_kmem_account();
3701 * kmalloc(<large_number>)
3702 * memcg_resume_kmem_account();
3704 * would effectively ignore the fact that we should skip accounting,
3705 * since it will drive us directly to this function without passing
3706 * through the cache selector memcg_kmem_get_cache. Such large
3707 * allocations are extremely rare but can happen, for instance, for the
3708 * cache arrays. We bring this test here.
3710 if (!current
->mm
|| current
->memcg_kmem_skip_account
)
3713 memcg
= try_get_mem_cgroup_from_mm(current
->mm
);
3716 * very rare case described in mem_cgroup_from_task. Unfortunately there
3717 * isn't much we can do without complicating this too much, and it would
3718 * be gfp-dependent anyway. Just let it go
3720 if (unlikely(!memcg
))
3723 if (!memcg_can_account_kmem(memcg
)) {
3724 css_put(&memcg
->css
);
3728 ret
= memcg_charge_kmem(memcg
, gfp
, PAGE_SIZE
<< order
);
3732 css_put(&memcg
->css
);
3736 void __memcg_kmem_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
3739 struct page_cgroup
*pc
;
3741 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3743 /* The page allocation failed. Revert */
3745 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3749 pc
= lookup_page_cgroup(page
);
3750 lock_page_cgroup(pc
);
3751 pc
->mem_cgroup
= memcg
;
3752 SetPageCgroupUsed(pc
);
3753 unlock_page_cgroup(pc
);
3756 void __memcg_kmem_uncharge_pages(struct page
*page
, int order
)
3758 struct mem_cgroup
*memcg
= NULL
;
3759 struct page_cgroup
*pc
;
3762 pc
= lookup_page_cgroup(page
);
3764 * Fast unlocked return. Theoretically might have changed, have to
3765 * check again after locking.
3767 if (!PageCgroupUsed(pc
))
3770 lock_page_cgroup(pc
);
3771 if (PageCgroupUsed(pc
)) {
3772 memcg
= pc
->mem_cgroup
;
3773 ClearPageCgroupUsed(pc
);
3775 unlock_page_cgroup(pc
);
3778 * We trust that only if there is a memcg associated with the page, it
3779 * is a valid allocation
3784 VM_BUG_ON(mem_cgroup_is_root(memcg
));
3785 memcg_uncharge_kmem(memcg
, PAGE_SIZE
<< order
);
3788 static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup
*memcg
)
3791 #endif /* CONFIG_MEMCG_KMEM */
3793 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3795 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
3797 * Because tail pages are not marked as "used", set it. We're under
3798 * zone->lru_lock, 'splitting on pmd' and compound_lock.
3799 * charge/uncharge will be never happen and move_account() is done under
3800 * compound_lock(), so we don't have to take care of races.
3802 void mem_cgroup_split_huge_fixup(struct page
*head
)
3804 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
3805 struct page_cgroup
*pc
;
3806 struct mem_cgroup
*memcg
;
3809 if (mem_cgroup_disabled())
3812 memcg
= head_pc
->mem_cgroup
;
3813 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
3815 pc
->mem_cgroup
= memcg
;
3816 smp_wmb();/* see __commit_charge() */
3817 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
3819 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
3822 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3825 void mem_cgroup_move_account_page_stat(struct mem_cgroup
*from
,
3826 struct mem_cgroup
*to
,
3827 unsigned int nr_pages
,
3828 enum mem_cgroup_stat_index idx
)
3830 /* Update stat data for mem_cgroup */
3832 __this_cpu_sub(from
->stat
->count
[idx
], nr_pages
);
3833 __this_cpu_add(to
->stat
->count
[idx
], nr_pages
);
3838 * mem_cgroup_move_account - move account of the page
3840 * @nr_pages: number of regular pages (>1 for huge pages)
3841 * @pc: page_cgroup of the page.
3842 * @from: mem_cgroup which the page is moved from.
3843 * @to: mem_cgroup which the page is moved to. @from != @to.
3845 * The caller must confirm following.
3846 * - page is not on LRU (isolate_page() is useful.)
3847 * - compound_lock is held when nr_pages > 1
3849 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
3852 static int mem_cgroup_move_account(struct page
*page
,
3853 unsigned int nr_pages
,
3854 struct page_cgroup
*pc
,
3855 struct mem_cgroup
*from
,
3856 struct mem_cgroup
*to
)
3858 unsigned long flags
;
3860 bool anon
= PageAnon(page
);
3862 VM_BUG_ON(from
== to
);
3863 VM_BUG_ON(PageLRU(page
));
3865 * The page is isolated from LRU. So, collapse function
3866 * will not handle this page. But page splitting can happen.
3867 * Do this check under compound_page_lock(). The caller should
3871 if (nr_pages
> 1 && !PageTransHuge(page
))
3874 lock_page_cgroup(pc
);
3877 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
3880 move_lock_mem_cgroup(from
, &flags
);
3882 if (!anon
&& page_mapped(page
))
3883 mem_cgroup_move_account_page_stat(from
, to
, nr_pages
,
3884 MEM_CGROUP_STAT_FILE_MAPPED
);
3886 if (PageWriteback(page
))
3887 mem_cgroup_move_account_page_stat(from
, to
, nr_pages
,
3888 MEM_CGROUP_STAT_WRITEBACK
);
3890 mem_cgroup_charge_statistics(from
, page
, anon
, -nr_pages
);
3892 /* caller should have done css_get */
3893 pc
->mem_cgroup
= to
;
3894 mem_cgroup_charge_statistics(to
, page
, anon
, nr_pages
);
3895 move_unlock_mem_cgroup(from
, &flags
);
3898 unlock_page_cgroup(pc
);
3902 memcg_check_events(to
, page
);
3903 memcg_check_events(from
, page
);
3909 * mem_cgroup_move_parent - moves page to the parent group
3910 * @page: the page to move
3911 * @pc: page_cgroup of the page
3912 * @child: page's cgroup
3914 * move charges to its parent or the root cgroup if the group has no
3915 * parent (aka use_hierarchy==0).
3916 * Although this might fail (get_page_unless_zero, isolate_lru_page or
3917 * mem_cgroup_move_account fails) the failure is always temporary and
3918 * it signals a race with a page removal/uncharge or migration. In the
3919 * first case the page is on the way out and it will vanish from the LRU
3920 * on the next attempt and the call should be retried later.
3921 * Isolation from the LRU fails only if page has been isolated from
3922 * the LRU since we looked at it and that usually means either global
3923 * reclaim or migration going on. The page will either get back to the
3925 * Finaly mem_cgroup_move_account fails only if the page got uncharged
3926 * (!PageCgroupUsed) or moved to a different group. The page will
3927 * disappear in the next attempt.
3929 static int mem_cgroup_move_parent(struct page
*page
,
3930 struct page_cgroup
*pc
,
3931 struct mem_cgroup
*child
)
3933 struct mem_cgroup
*parent
;
3934 unsigned int nr_pages
;
3935 unsigned long uninitialized_var(flags
);
3938 VM_BUG_ON(mem_cgroup_is_root(child
));
3941 if (!get_page_unless_zero(page
))
3943 if (isolate_lru_page(page
))
3946 nr_pages
= hpage_nr_pages(page
);
3948 parent
= parent_mem_cgroup(child
);
3950 * If no parent, move charges to root cgroup.
3953 parent
= root_mem_cgroup
;
3956 VM_BUG_ON(!PageTransHuge(page
));
3957 flags
= compound_lock_irqsave(page
);
3960 ret
= mem_cgroup_move_account(page
, nr_pages
,
3963 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
3966 compound_unlock_irqrestore(page
, flags
);
3967 putback_lru_page(page
);
3975 * Charge the memory controller for page usage.
3977 * 0 if the charge was successful
3978 * < 0 if the cgroup is over its limit
3980 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
3981 gfp_t gfp_mask
, enum charge_type ctype
)
3983 struct mem_cgroup
*memcg
= NULL
;
3984 unsigned int nr_pages
= 1;
3988 if (PageTransHuge(page
)) {
3989 nr_pages
<<= compound_order(page
);
3990 VM_BUG_ON(!PageTransHuge(page
));
3992 * Never OOM-kill a process for a huge page. The
3993 * fault handler will fall back to regular pages.
3998 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
4001 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
4005 int mem_cgroup_newpage_charge(struct page
*page
,
4006 struct mm_struct
*mm
, gfp_t gfp_mask
)
4008 if (mem_cgroup_disabled())
4010 VM_BUG_ON(page_mapped(page
));
4011 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
4013 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
4014 MEM_CGROUP_CHARGE_TYPE_ANON
);
4018 * While swap-in, try_charge -> commit or cancel, the page is locked.
4019 * And when try_charge() successfully returns, one refcnt to memcg without
4020 * struct page_cgroup is acquired. This refcnt will be consumed by
4021 * "commit()" or removed by "cancel()"
4023 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
4026 struct mem_cgroup
**memcgp
)
4028 struct mem_cgroup
*memcg
;
4029 struct page_cgroup
*pc
;
4032 pc
= lookup_page_cgroup(page
);
4034 * Every swap fault against a single page tries to charge the
4035 * page, bail as early as possible. shmem_unuse() encounters
4036 * already charged pages, too. The USED bit is protected by
4037 * the page lock, which serializes swap cache removal, which
4038 * in turn serializes uncharging.
4040 if (PageCgroupUsed(pc
))
4042 if (!do_swap_account
)
4044 memcg
= try_get_mem_cgroup_from_page(page
);
4048 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
4049 css_put(&memcg
->css
);
4054 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
4060 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
4061 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
4064 if (mem_cgroup_disabled())
4067 * A racing thread's fault, or swapoff, may have already
4068 * updated the pte, and even removed page from swap cache: in
4069 * those cases unuse_pte()'s pte_same() test will fail; but
4070 * there's also a KSM case which does need to charge the page.
4072 if (!PageSwapCache(page
)) {
4075 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
4080 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
4083 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
4085 if (mem_cgroup_disabled())
4089 __mem_cgroup_cancel_charge(memcg
, 1);
4093 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
4094 enum charge_type ctype
)
4096 if (mem_cgroup_disabled())
4101 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
4103 * Now swap is on-memory. This means this page may be
4104 * counted both as mem and swap....double count.
4105 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
4106 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
4107 * may call delete_from_swap_cache() before reach here.
4109 if (do_swap_account
&& PageSwapCache(page
)) {
4110 swp_entry_t ent
= {.val
= page_private(page
)};
4111 mem_cgroup_uncharge_swap(ent
);
4115 void mem_cgroup_commit_charge_swapin(struct page
*page
,
4116 struct mem_cgroup
*memcg
)
4118 __mem_cgroup_commit_charge_swapin(page
, memcg
,
4119 MEM_CGROUP_CHARGE_TYPE_ANON
);
4122 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
4125 struct mem_cgroup
*memcg
= NULL
;
4126 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4129 if (mem_cgroup_disabled())
4131 if (PageCompound(page
))
4134 if (!PageSwapCache(page
))
4135 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
4136 else { /* page is swapcache/shmem */
4137 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
4140 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
4145 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
4146 unsigned int nr_pages
,
4147 const enum charge_type ctype
)
4149 struct memcg_batch_info
*batch
= NULL
;
4150 bool uncharge_memsw
= true;
4152 /* If swapout, usage of swap doesn't decrease */
4153 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
4154 uncharge_memsw
= false;
4156 batch
= ¤t
->memcg_batch
;
4158 * In usual, we do css_get() when we remember memcg pointer.
4159 * But in this case, we keep res->usage until end of a series of
4160 * uncharges. Then, it's ok to ignore memcg's refcnt.
4163 batch
->memcg
= memcg
;
4165 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
4166 * In those cases, all pages freed continuously can be expected to be in
4167 * the same cgroup and we have chance to coalesce uncharges.
4168 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
4169 * because we want to do uncharge as soon as possible.
4172 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
4173 goto direct_uncharge
;
4176 goto direct_uncharge
;
4179 * In typical case, batch->memcg == mem. This means we can
4180 * merge a series of uncharges to an uncharge of res_counter.
4181 * If not, we uncharge res_counter ony by one.
4183 if (batch
->memcg
!= memcg
)
4184 goto direct_uncharge
;
4185 /* remember freed charge and uncharge it later */
4188 batch
->memsw_nr_pages
++;
4191 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
4193 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
4194 if (unlikely(batch
->memcg
!= memcg
))
4195 memcg_oom_recover(memcg
);
4199 * uncharge if !page_mapped(page)
4201 static struct mem_cgroup
*
4202 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
4205 struct mem_cgroup
*memcg
= NULL
;
4206 unsigned int nr_pages
= 1;
4207 struct page_cgroup
*pc
;
4210 if (mem_cgroup_disabled())
4213 if (PageTransHuge(page
)) {
4214 nr_pages
<<= compound_order(page
);
4215 VM_BUG_ON(!PageTransHuge(page
));
4218 * Check if our page_cgroup is valid
4220 pc
= lookup_page_cgroup(page
);
4221 if (unlikely(!PageCgroupUsed(pc
)))
4224 lock_page_cgroup(pc
);
4226 memcg
= pc
->mem_cgroup
;
4228 if (!PageCgroupUsed(pc
))
4231 anon
= PageAnon(page
);
4234 case MEM_CGROUP_CHARGE_TYPE_ANON
:
4236 * Generally PageAnon tells if it's the anon statistics to be
4237 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
4238 * used before page reached the stage of being marked PageAnon.
4242 case MEM_CGROUP_CHARGE_TYPE_DROP
:
4243 /* See mem_cgroup_prepare_migration() */
4244 if (page_mapped(page
))
4247 * Pages under migration may not be uncharged. But
4248 * end_migration() /must/ be the one uncharging the
4249 * unused post-migration page and so it has to call
4250 * here with the migration bit still set. See the
4251 * res_counter handling below.
4253 if (!end_migration
&& PageCgroupMigration(pc
))
4256 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
4257 if (!PageAnon(page
)) { /* Shared memory */
4258 if (page
->mapping
&& !page_is_file_cache(page
))
4260 } else if (page_mapped(page
)) /* Anon */
4267 mem_cgroup_charge_statistics(memcg
, page
, anon
, -nr_pages
);
4269 ClearPageCgroupUsed(pc
);
4271 * pc->mem_cgroup is not cleared here. It will be accessed when it's
4272 * freed from LRU. This is safe because uncharged page is expected not
4273 * to be reused (freed soon). Exception is SwapCache, it's handled by
4274 * special functions.
4277 unlock_page_cgroup(pc
);
4279 * even after unlock, we have memcg->res.usage here and this memcg
4280 * will never be freed, so it's safe to call css_get().
4282 memcg_check_events(memcg
, page
);
4283 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
4284 mem_cgroup_swap_statistics(memcg
, true);
4285 css_get(&memcg
->css
);
4288 * Migration does not charge the res_counter for the
4289 * replacement page, so leave it alone when phasing out the
4290 * page that is unused after the migration.
4292 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
4293 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
4298 unlock_page_cgroup(pc
);
4302 void mem_cgroup_uncharge_page(struct page
*page
)
4305 if (page_mapped(page
))
4307 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
4309 * If the page is in swap cache, uncharge should be deferred
4310 * to the swap path, which also properly accounts swap usage
4311 * and handles memcg lifetime.
4313 * Note that this check is not stable and reclaim may add the
4314 * page to swap cache at any time after this. However, if the
4315 * page is not in swap cache by the time page->mapcount hits
4316 * 0, there won't be any page table references to the swap
4317 * slot, and reclaim will free it and not actually write the
4320 if (PageSwapCache(page
))
4322 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
4325 void mem_cgroup_uncharge_cache_page(struct page
*page
)
4327 VM_BUG_ON(page_mapped(page
));
4328 VM_BUG_ON(page
->mapping
);
4329 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
4333 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
4334 * In that cases, pages are freed continuously and we can expect pages
4335 * are in the same memcg. All these calls itself limits the number of
4336 * pages freed at once, then uncharge_start/end() is called properly.
4337 * This may be called prural(2) times in a context,
4340 void mem_cgroup_uncharge_start(void)
4342 current
->memcg_batch
.do_batch
++;
4343 /* We can do nest. */
4344 if (current
->memcg_batch
.do_batch
== 1) {
4345 current
->memcg_batch
.memcg
= NULL
;
4346 current
->memcg_batch
.nr_pages
= 0;
4347 current
->memcg_batch
.memsw_nr_pages
= 0;
4351 void mem_cgroup_uncharge_end(void)
4353 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
4355 if (!batch
->do_batch
)
4359 if (batch
->do_batch
) /* If stacked, do nothing. */
4365 * This "batch->memcg" is valid without any css_get/put etc...
4366 * bacause we hide charges behind us.
4368 if (batch
->nr_pages
)
4369 res_counter_uncharge(&batch
->memcg
->res
,
4370 batch
->nr_pages
* PAGE_SIZE
);
4371 if (batch
->memsw_nr_pages
)
4372 res_counter_uncharge(&batch
->memcg
->memsw
,
4373 batch
->memsw_nr_pages
* PAGE_SIZE
);
4374 memcg_oom_recover(batch
->memcg
);
4375 /* forget this pointer (for sanity check) */
4376 batch
->memcg
= NULL
;
4381 * called after __delete_from_swap_cache() and drop "page" account.
4382 * memcg information is recorded to swap_cgroup of "ent"
4385 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
4387 struct mem_cgroup
*memcg
;
4388 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
4390 if (!swapout
) /* this was a swap cache but the swap is unused ! */
4391 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
4393 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
4396 * record memcg information, if swapout && memcg != NULL,
4397 * css_get() was called in uncharge().
4399 if (do_swap_account
&& swapout
&& memcg
)
4400 swap_cgroup_record(ent
, mem_cgroup_id(memcg
));
4404 #ifdef CONFIG_MEMCG_SWAP
4406 * called from swap_entry_free(). remove record in swap_cgroup and
4407 * uncharge "memsw" account.
4409 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
4411 struct mem_cgroup
*memcg
;
4414 if (!do_swap_account
)
4417 id
= swap_cgroup_record(ent
, 0);
4419 memcg
= mem_cgroup_lookup(id
);
4422 * We uncharge this because swap is freed.
4423 * This memcg can be obsolete one. We avoid calling css_tryget
4425 if (!mem_cgroup_is_root(memcg
))
4426 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
4427 mem_cgroup_swap_statistics(memcg
, false);
4428 css_put(&memcg
->css
);
4434 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
4435 * @entry: swap entry to be moved
4436 * @from: mem_cgroup which the entry is moved from
4437 * @to: mem_cgroup which the entry is moved to
4439 * It succeeds only when the swap_cgroup's record for this entry is the same
4440 * as the mem_cgroup's id of @from.
4442 * Returns 0 on success, -EINVAL on failure.
4444 * The caller must have charged to @to, IOW, called res_counter_charge() about
4445 * both res and memsw, and called css_get().
4447 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
4448 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4450 unsigned short old_id
, new_id
;
4452 old_id
= mem_cgroup_id(from
);
4453 new_id
= mem_cgroup_id(to
);
4455 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
4456 mem_cgroup_swap_statistics(from
, false);
4457 mem_cgroup_swap_statistics(to
, true);
4459 * This function is only called from task migration context now.
4460 * It postpones res_counter and refcount handling till the end
4461 * of task migration(mem_cgroup_clear_mc()) for performance
4462 * improvement. But we cannot postpone css_get(to) because if
4463 * the process that has been moved to @to does swap-in, the
4464 * refcount of @to might be decreased to 0.
4466 * We are in attach() phase, so the cgroup is guaranteed to be
4467 * alive, so we can just call css_get().
4475 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
4476 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
4483 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
4486 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
4487 struct mem_cgroup
**memcgp
)
4489 struct mem_cgroup
*memcg
= NULL
;
4490 unsigned int nr_pages
= 1;
4491 struct page_cgroup
*pc
;
4492 enum charge_type ctype
;
4496 if (mem_cgroup_disabled())
4499 if (PageTransHuge(page
))
4500 nr_pages
<<= compound_order(page
);
4502 pc
= lookup_page_cgroup(page
);
4503 lock_page_cgroup(pc
);
4504 if (PageCgroupUsed(pc
)) {
4505 memcg
= pc
->mem_cgroup
;
4506 css_get(&memcg
->css
);
4508 * At migrating an anonymous page, its mapcount goes down
4509 * to 0 and uncharge() will be called. But, even if it's fully
4510 * unmapped, migration may fail and this page has to be
4511 * charged again. We set MIGRATION flag here and delay uncharge
4512 * until end_migration() is called
4514 * Corner Case Thinking
4516 * When the old page was mapped as Anon and it's unmap-and-freed
4517 * while migration was ongoing.
4518 * If unmap finds the old page, uncharge() of it will be delayed
4519 * until end_migration(). If unmap finds a new page, it's
4520 * uncharged when it make mapcount to be 1->0. If unmap code
4521 * finds swap_migration_entry, the new page will not be mapped
4522 * and end_migration() will find it(mapcount==0).
4525 * When the old page was mapped but migraion fails, the kernel
4526 * remaps it. A charge for it is kept by MIGRATION flag even
4527 * if mapcount goes down to 0. We can do remap successfully
4528 * without charging it again.
4531 * The "old" page is under lock_page() until the end of
4532 * migration, so, the old page itself will not be swapped-out.
4533 * If the new page is swapped out before end_migraton, our
4534 * hook to usual swap-out path will catch the event.
4537 SetPageCgroupMigration(pc
);
4539 unlock_page_cgroup(pc
);
4541 * If the page is not charged at this point,
4549 * We charge new page before it's used/mapped. So, even if unlock_page()
4550 * is called before end_migration, we can catch all events on this new
4551 * page. In the case new page is migrated but not remapped, new page's
4552 * mapcount will be finally 0 and we call uncharge in end_migration().
4555 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
4557 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4559 * The page is committed to the memcg, but it's not actually
4560 * charged to the res_counter since we plan on replacing the
4561 * old one and only one page is going to be left afterwards.
4563 __mem_cgroup_commit_charge(memcg
, newpage
, nr_pages
, ctype
, false);
4566 /* remove redundant charge if migration failed*/
4567 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
4568 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
4570 struct page
*used
, *unused
;
4571 struct page_cgroup
*pc
;
4577 if (!migration_ok
) {
4584 anon
= PageAnon(used
);
4585 __mem_cgroup_uncharge_common(unused
,
4586 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
4587 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
4589 css_put(&memcg
->css
);
4591 * We disallowed uncharge of pages under migration because mapcount
4592 * of the page goes down to zero, temporarly.
4593 * Clear the flag and check the page should be charged.
4595 pc
= lookup_page_cgroup(oldpage
);
4596 lock_page_cgroup(pc
);
4597 ClearPageCgroupMigration(pc
);
4598 unlock_page_cgroup(pc
);
4601 * If a page is a file cache, radix-tree replacement is very atomic
4602 * and we can skip this check. When it was an Anon page, its mapcount
4603 * goes down to 0. But because we added MIGRATION flage, it's not
4604 * uncharged yet. There are several case but page->mapcount check
4605 * and USED bit check in mem_cgroup_uncharge_page() will do enough
4606 * check. (see prepare_charge() also)
4609 mem_cgroup_uncharge_page(used
);
4613 * At replace page cache, newpage is not under any memcg but it's on
4614 * LRU. So, this function doesn't touch res_counter but handles LRU
4615 * in correct way. Both pages are locked so we cannot race with uncharge.
4617 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
4618 struct page
*newpage
)
4620 struct mem_cgroup
*memcg
= NULL
;
4621 struct page_cgroup
*pc
;
4622 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
4624 if (mem_cgroup_disabled())
4627 pc
= lookup_page_cgroup(oldpage
);
4628 /* fix accounting on old pages */
4629 lock_page_cgroup(pc
);
4630 if (PageCgroupUsed(pc
)) {
4631 memcg
= pc
->mem_cgroup
;
4632 mem_cgroup_charge_statistics(memcg
, oldpage
, false, -1);
4633 ClearPageCgroupUsed(pc
);
4635 unlock_page_cgroup(pc
);
4638 * When called from shmem_replace_page(), in some cases the
4639 * oldpage has already been charged, and in some cases not.
4644 * Even if newpage->mapping was NULL before starting replacement,
4645 * the newpage may be on LRU(or pagevec for LRU) already. We lock
4646 * LRU while we overwrite pc->mem_cgroup.
4648 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
4651 #ifdef CONFIG_DEBUG_VM
4652 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
4654 struct page_cgroup
*pc
;
4656 pc
= lookup_page_cgroup(page
);
4658 * Can be NULL while feeding pages into the page allocator for
4659 * the first time, i.e. during boot or memory hotplug;
4660 * or when mem_cgroup_disabled().
4662 if (likely(pc
) && PageCgroupUsed(pc
))
4667 bool mem_cgroup_bad_page_check(struct page
*page
)
4669 if (mem_cgroup_disabled())
4672 return lookup_page_cgroup_used(page
) != NULL
;
4675 void mem_cgroup_print_bad_page(struct page
*page
)
4677 struct page_cgroup
*pc
;
4679 pc
= lookup_page_cgroup_used(page
);
4681 pr_alert("pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
4682 pc
, pc
->flags
, pc
->mem_cgroup
);
4687 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
4688 unsigned long long val
)
4691 u64 memswlimit
, memlimit
;
4693 int children
= mem_cgroup_count_children(memcg
);
4694 u64 curusage
, oldusage
;
4698 * For keeping hierarchical_reclaim simple, how long we should retry
4699 * is depends on callers. We set our retry-count to be function
4700 * of # of children which we should visit in this loop.
4702 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
4704 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4707 while (retry_count
) {
4708 if (signal_pending(current
)) {
4713 * Rather than hide all in some function, I do this in
4714 * open coded manner. You see what this really does.
4715 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4717 mutex_lock(&set_limit_mutex
);
4718 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4719 if (memswlimit
< val
) {
4721 mutex_unlock(&set_limit_mutex
);
4725 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4729 ret
= res_counter_set_limit(&memcg
->res
, val
);
4731 if (memswlimit
== val
)
4732 memcg
->memsw_is_minimum
= true;
4734 memcg
->memsw_is_minimum
= false;
4736 mutex_unlock(&set_limit_mutex
);
4741 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4742 MEM_CGROUP_RECLAIM_SHRINK
);
4743 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
4744 /* Usage is reduced ? */
4745 if (curusage
>= oldusage
)
4748 oldusage
= curusage
;
4750 if (!ret
&& enlarge
)
4751 memcg_oom_recover(memcg
);
4756 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
4757 unsigned long long val
)
4760 u64 memlimit
, memswlimit
, oldusage
, curusage
;
4761 int children
= mem_cgroup_count_children(memcg
);
4765 /* see mem_cgroup_resize_res_limit */
4766 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
4767 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4768 while (retry_count
) {
4769 if (signal_pending(current
)) {
4774 * Rather than hide all in some function, I do this in
4775 * open coded manner. You see what this really does.
4776 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
4778 mutex_lock(&set_limit_mutex
);
4779 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4780 if (memlimit
> val
) {
4782 mutex_unlock(&set_limit_mutex
);
4785 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4786 if (memswlimit
< val
)
4788 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
4790 if (memlimit
== val
)
4791 memcg
->memsw_is_minimum
= true;
4793 memcg
->memsw_is_minimum
= false;
4795 mutex_unlock(&set_limit_mutex
);
4800 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
4801 MEM_CGROUP_RECLAIM_NOSWAP
|
4802 MEM_CGROUP_RECLAIM_SHRINK
);
4803 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
4804 /* Usage is reduced ? */
4805 if (curusage
>= oldusage
)
4808 oldusage
= curusage
;
4810 if (!ret
&& enlarge
)
4811 memcg_oom_recover(memcg
);
4815 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
4817 unsigned long *total_scanned
)
4819 unsigned long nr_reclaimed
= 0;
4820 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
4821 unsigned long reclaimed
;
4823 struct mem_cgroup_tree_per_zone
*mctz
;
4824 unsigned long long excess
;
4825 unsigned long nr_scanned
;
4830 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
4832 * This loop can run a while, specially if mem_cgroup's continuously
4833 * keep exceeding their soft limit and putting the system under
4840 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
4845 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
4846 gfp_mask
, &nr_scanned
);
4847 nr_reclaimed
+= reclaimed
;
4848 *total_scanned
+= nr_scanned
;
4849 spin_lock(&mctz
->lock
);
4852 * If we failed to reclaim anything from this memory cgroup
4853 * it is time to move on to the next cgroup
4859 * Loop until we find yet another one.
4861 * By the time we get the soft_limit lock
4862 * again, someone might have aded the
4863 * group back on the RB tree. Iterate to
4864 * make sure we get a different mem.
4865 * mem_cgroup_largest_soft_limit_node returns
4866 * NULL if no other cgroup is present on
4870 __mem_cgroup_largest_soft_limit_node(mctz
);
4872 css_put(&next_mz
->memcg
->css
);
4873 else /* next_mz == NULL or other memcg */
4877 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
4878 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
4880 * One school of thought says that we should not add
4881 * back the node to the tree if reclaim returns 0.
4882 * But our reclaim could return 0, simply because due
4883 * to priority we are exposing a smaller subset of
4884 * memory to reclaim from. Consider this as a longer
4887 /* If excess == 0, no tree ops */
4888 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
4889 spin_unlock(&mctz
->lock
);
4890 css_put(&mz
->memcg
->css
);
4893 * Could not reclaim anything and there are no more
4894 * mem cgroups to try or we seem to be looping without
4895 * reclaiming anything.
4897 if (!nr_reclaimed
&&
4899 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
4901 } while (!nr_reclaimed
);
4903 css_put(&next_mz
->memcg
->css
);
4904 return nr_reclaimed
;
4908 * mem_cgroup_force_empty_list - clears LRU of a group
4909 * @memcg: group to clear
4912 * @lru: lru to to clear
4914 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
4915 * reclaim the pages page themselves - pages are moved to the parent (or root)
4918 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
4919 int node
, int zid
, enum lru_list lru
)
4921 struct lruvec
*lruvec
;
4922 unsigned long flags
;
4923 struct list_head
*list
;
4927 zone
= &NODE_DATA(node
)->node_zones
[zid
];
4928 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
4929 list
= &lruvec
->lists
[lru
];
4933 struct page_cgroup
*pc
;
4936 spin_lock_irqsave(&zone
->lru_lock
, flags
);
4937 if (list_empty(list
)) {
4938 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4941 page
= list_entry(list
->prev
, struct page
, lru
);
4943 list_move(&page
->lru
, list
);
4945 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4948 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
4950 pc
= lookup_page_cgroup(page
);
4952 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
4953 /* found lock contention or "pc" is obsolete. */
4958 } while (!list_empty(list
));
4962 * make mem_cgroup's charge to be 0 if there is no task by moving
4963 * all the charges and pages to the parent.
4964 * This enables deleting this mem_cgroup.
4966 * Caller is responsible for holding css reference on the memcg.
4968 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
4974 /* This is for making all *used* pages to be on LRU. */
4975 lru_add_drain_all();
4976 drain_all_stock_sync(memcg
);
4977 mem_cgroup_start_move(memcg
);
4978 for_each_node_state(node
, N_MEMORY
) {
4979 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4982 mem_cgroup_force_empty_list(memcg
,
4987 mem_cgroup_end_move(memcg
);
4988 memcg_oom_recover(memcg
);
4992 * Kernel memory may not necessarily be trackable to a specific
4993 * process. So they are not migrated, and therefore we can't
4994 * expect their value to drop to 0 here.
4995 * Having res filled up with kmem only is enough.
4997 * This is a safety check because mem_cgroup_force_empty_list
4998 * could have raced with mem_cgroup_replace_page_cache callers
4999 * so the lru seemed empty but the page could have been added
5000 * right after the check. RES_USAGE should be safe as we always
5001 * charge before adding to the LRU.
5003 usage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
) -
5004 res_counter_read_u64(&memcg
->kmem
, RES_USAGE
);
5005 } while (usage
> 0);
5008 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
5010 lockdep_assert_held(&memcg_create_mutex
);
5012 * The lock does not prevent addition or deletion to the list
5013 * of children, but it prevents a new child from being
5014 * initialized based on this parent in css_online(), so it's
5015 * enough to decide whether hierarchically inherited
5016 * attributes can still be changed or not.
5018 return memcg
->use_hierarchy
&&
5019 !list_empty(&memcg
->css
.cgroup
->children
);
5023 * Reclaims as many pages from the given memcg as possible and moves
5024 * the rest to the parent.
5026 * Caller is responsible for holding css reference for memcg.
5028 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
5030 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
5031 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
5033 /* returns EBUSY if there is a task or if we come here twice. */
5034 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
5037 /* we call try-to-free pages for make this cgroup empty */
5038 lru_add_drain_all();
5039 /* try to free all pages in this cgroup */
5040 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
5043 if (signal_pending(current
))
5046 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
5050 /* maybe some writeback is necessary */
5051 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
5056 mem_cgroup_reparent_charges(memcg
);
5061 static int mem_cgroup_force_empty_write(struct cgroup_subsys_state
*css
,
5064 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5066 if (mem_cgroup_is_root(memcg
))
5068 return mem_cgroup_force_empty(memcg
);
5071 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
5074 return mem_cgroup_from_css(css
)->use_hierarchy
;
5077 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
5078 struct cftype
*cft
, u64 val
)
5081 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5082 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5084 mutex_lock(&memcg_create_mutex
);
5086 if (memcg
->use_hierarchy
== val
)
5090 * If parent's use_hierarchy is set, we can't make any modifications
5091 * in the child subtrees. If it is unset, then the change can
5092 * occur, provided the current cgroup has no children.
5094 * For the root cgroup, parent_mem is NULL, we allow value to be
5095 * set if there are no children.
5097 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
5098 (val
== 1 || val
== 0)) {
5099 if (list_empty(&memcg
->css
.cgroup
->children
))
5100 memcg
->use_hierarchy
= val
;
5107 mutex_unlock(&memcg_create_mutex
);
5113 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
5114 enum mem_cgroup_stat_index idx
)
5116 struct mem_cgroup
*iter
;
5119 /* Per-cpu values can be negative, use a signed accumulator */
5120 for_each_mem_cgroup_tree(iter
, memcg
)
5121 val
+= mem_cgroup_read_stat(iter
, idx
);
5123 if (val
< 0) /* race ? */
5128 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
5132 if (!mem_cgroup_is_root(memcg
)) {
5134 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
5136 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
5140 * Transparent hugepages are still accounted for in MEM_CGROUP_STAT_RSS
5141 * as well as in MEM_CGROUP_STAT_RSS_HUGE.
5143 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
5144 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
5147 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
5149 return val
<< PAGE_SHIFT
;
5152 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
5155 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5160 type
= MEMFILE_TYPE(cft
->private);
5161 name
= MEMFILE_ATTR(cft
->private);
5165 if (name
== RES_USAGE
)
5166 val
= mem_cgroup_usage(memcg
, false);
5168 val
= res_counter_read_u64(&memcg
->res
, name
);
5171 if (name
== RES_USAGE
)
5172 val
= mem_cgroup_usage(memcg
, true);
5174 val
= res_counter_read_u64(&memcg
->memsw
, name
);
5177 val
= res_counter_read_u64(&memcg
->kmem
, name
);
5186 static int memcg_update_kmem_limit(struct cgroup_subsys_state
*css
, u64 val
)
5189 #ifdef CONFIG_MEMCG_KMEM
5190 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5192 * For simplicity, we won't allow this to be disabled. It also can't
5193 * be changed if the cgroup has children already, or if tasks had
5196 * If tasks join before we set the limit, a person looking at
5197 * kmem.usage_in_bytes will have no way to determine when it took
5198 * place, which makes the value quite meaningless.
5200 * After it first became limited, changes in the value of the limit are
5201 * of course permitted.
5203 mutex_lock(&memcg_create_mutex
);
5204 mutex_lock(&set_limit_mutex
);
5205 if (!memcg
->kmem_account_flags
&& val
!= RES_COUNTER_MAX
) {
5206 if (cgroup_task_count(css
->cgroup
) || memcg_has_children(memcg
)) {
5210 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5213 ret
= memcg_update_cache_sizes(memcg
);
5215 res_counter_set_limit(&memcg
->kmem
, RES_COUNTER_MAX
);
5218 static_key_slow_inc(&memcg_kmem_enabled_key
);
5220 * setting the active bit after the inc will guarantee no one
5221 * starts accounting before all call sites are patched
5223 memcg_kmem_set_active(memcg
);
5225 ret
= res_counter_set_limit(&memcg
->kmem
, val
);
5227 mutex_unlock(&set_limit_mutex
);
5228 mutex_unlock(&memcg_create_mutex
);
5233 #ifdef CONFIG_MEMCG_KMEM
5234 static int memcg_propagate_kmem(struct mem_cgroup
*memcg
)
5237 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5241 memcg
->kmem_account_flags
= parent
->kmem_account_flags
;
5243 * When that happen, we need to disable the static branch only on those
5244 * memcgs that enabled it. To achieve this, we would be forced to
5245 * complicate the code by keeping track of which memcgs were the ones
5246 * that actually enabled limits, and which ones got it from its
5249 * It is a lot simpler just to do static_key_slow_inc() on every child
5250 * that is accounted.
5252 if (!memcg_kmem_is_active(memcg
))
5256 * __mem_cgroup_free() will issue static_key_slow_dec() because this
5257 * memcg is active already. If the later initialization fails then the
5258 * cgroup core triggers the cleanup so we do not have to do it here.
5260 static_key_slow_inc(&memcg_kmem_enabled_key
);
5262 mutex_lock(&set_limit_mutex
);
5263 memcg_stop_kmem_account();
5264 ret
= memcg_update_cache_sizes(memcg
);
5265 memcg_resume_kmem_account();
5266 mutex_unlock(&set_limit_mutex
);
5270 #endif /* CONFIG_MEMCG_KMEM */
5273 * The user of this function is...
5276 static int mem_cgroup_write(struct cgroup_subsys_state
*css
, struct cftype
*cft
,
5279 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5282 unsigned long long val
;
5285 type
= MEMFILE_TYPE(cft
->private);
5286 name
= MEMFILE_ATTR(cft
->private);
5290 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
5294 /* This function does all necessary parse...reuse it */
5295 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5299 ret
= mem_cgroup_resize_limit(memcg
, val
);
5300 else if (type
== _MEMSWAP
)
5301 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
5302 else if (type
== _KMEM
)
5303 ret
= memcg_update_kmem_limit(css
, val
);
5307 case RES_SOFT_LIMIT
:
5308 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
5312 * For memsw, soft limits are hard to implement in terms
5313 * of semantics, for now, we support soft limits for
5314 * control without swap
5317 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
5322 ret
= -EINVAL
; /* should be BUG() ? */
5328 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
5329 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
5331 unsigned long long min_limit
, min_memsw_limit
, tmp
;
5333 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5334 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5335 if (!memcg
->use_hierarchy
)
5338 while (css_parent(&memcg
->css
)) {
5339 memcg
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5340 if (!memcg
->use_hierarchy
)
5342 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
5343 min_limit
= min(min_limit
, tmp
);
5344 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
5345 min_memsw_limit
= min(min_memsw_limit
, tmp
);
5348 *mem_limit
= min_limit
;
5349 *memsw_limit
= min_memsw_limit
;
5352 static int mem_cgroup_reset(struct cgroup_subsys_state
*css
, unsigned int event
)
5354 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5358 type
= MEMFILE_TYPE(event
);
5359 name
= MEMFILE_ATTR(event
);
5364 res_counter_reset_max(&memcg
->res
);
5365 else if (type
== _MEMSWAP
)
5366 res_counter_reset_max(&memcg
->memsw
);
5367 else if (type
== _KMEM
)
5368 res_counter_reset_max(&memcg
->kmem
);
5374 res_counter_reset_failcnt(&memcg
->res
);
5375 else if (type
== _MEMSWAP
)
5376 res_counter_reset_failcnt(&memcg
->memsw
);
5377 else if (type
== _KMEM
)
5378 res_counter_reset_failcnt(&memcg
->kmem
);
5387 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
5390 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
5394 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5395 struct cftype
*cft
, u64 val
)
5397 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5399 if (val
>= (1 << NR_MOVE_TYPE
))
5403 * No kind of locking is needed in here, because ->can_attach() will
5404 * check this value once in the beginning of the process, and then carry
5405 * on with stale data. This means that changes to this value will only
5406 * affect task migrations starting after the change.
5408 memcg
->move_charge_at_immigrate
= val
;
5412 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
5413 struct cftype
*cft
, u64 val
)
5420 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
5424 unsigned int lru_mask
;
5427 static const struct numa_stat stats
[] = {
5428 { "total", LRU_ALL
},
5429 { "file", LRU_ALL_FILE
},
5430 { "anon", LRU_ALL_ANON
},
5431 { "unevictable", BIT(LRU_UNEVICTABLE
) },
5433 const struct numa_stat
*stat
;
5436 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5438 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5439 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
5440 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
5441 for_each_node_state(nid
, N_MEMORY
) {
5442 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
5444 seq_printf(m
, " N%d=%lu", nid
, nr
);
5449 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
5450 struct mem_cgroup
*iter
;
5453 for_each_mem_cgroup_tree(iter
, memcg
)
5454 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
5455 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
5456 for_each_node_state(nid
, N_MEMORY
) {
5458 for_each_mem_cgroup_tree(iter
, memcg
)
5459 nr
+= mem_cgroup_node_nr_lru_pages(
5460 iter
, nid
, stat
->lru_mask
);
5461 seq_printf(m
, " N%d=%lu", nid
, nr
);
5468 #endif /* CONFIG_NUMA */
5470 static inline void mem_cgroup_lru_names_not_uptodate(void)
5472 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
5475 static int memcg_stat_show(struct seq_file
*m
, void *v
)
5477 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5478 struct mem_cgroup
*mi
;
5481 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5482 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5484 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
5485 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
5488 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
5489 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
5490 mem_cgroup_read_events(memcg
, i
));
5492 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
5493 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
5494 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
5496 /* Hierarchical information */
5498 unsigned long long limit
, memsw_limit
;
5499 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
5500 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
5501 if (do_swap_account
)
5502 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
5506 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
5509 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
5511 for_each_mem_cgroup_tree(mi
, memcg
)
5512 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
5513 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
5516 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
5517 unsigned long long val
= 0;
5519 for_each_mem_cgroup_tree(mi
, memcg
)
5520 val
+= mem_cgroup_read_events(mi
, i
);
5521 seq_printf(m
, "total_%s %llu\n",
5522 mem_cgroup_events_names
[i
], val
);
5525 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5526 unsigned long long val
= 0;
5528 for_each_mem_cgroup_tree(mi
, memcg
)
5529 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
5530 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
5533 #ifdef CONFIG_DEBUG_VM
5536 struct mem_cgroup_per_zone
*mz
;
5537 struct zone_reclaim_stat
*rstat
;
5538 unsigned long recent_rotated
[2] = {0, 0};
5539 unsigned long recent_scanned
[2] = {0, 0};
5541 for_each_online_node(nid
)
5542 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
5543 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
5544 rstat
= &mz
->lruvec
.reclaim_stat
;
5546 recent_rotated
[0] += rstat
->recent_rotated
[0];
5547 recent_rotated
[1] += rstat
->recent_rotated
[1];
5548 recent_scanned
[0] += rstat
->recent_scanned
[0];
5549 recent_scanned
[1] += rstat
->recent_scanned
[1];
5551 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
5552 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
5553 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
5554 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
5561 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
5564 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5566 return mem_cgroup_swappiness(memcg
);
5569 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
5570 struct cftype
*cft
, u64 val
)
5572 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5573 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5575 if (val
> 100 || !parent
)
5578 mutex_lock(&memcg_create_mutex
);
5580 /* If under hierarchy, only empty-root can set this value */
5581 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5582 mutex_unlock(&memcg_create_mutex
);
5586 memcg
->swappiness
= val
;
5588 mutex_unlock(&memcg_create_mutex
);
5593 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
5595 struct mem_cgroup_threshold_ary
*t
;
5601 t
= rcu_dereference(memcg
->thresholds
.primary
);
5603 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
5608 usage
= mem_cgroup_usage(memcg
, swap
);
5611 * current_threshold points to threshold just below or equal to usage.
5612 * If it's not true, a threshold was crossed after last
5613 * call of __mem_cgroup_threshold().
5615 i
= t
->current_threshold
;
5618 * Iterate backward over array of thresholds starting from
5619 * current_threshold and check if a threshold is crossed.
5620 * If none of thresholds below usage is crossed, we read
5621 * only one element of the array here.
5623 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
5624 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5626 /* i = current_threshold + 1 */
5630 * Iterate forward over array of thresholds starting from
5631 * current_threshold+1 and check if a threshold is crossed.
5632 * If none of thresholds above usage is crossed, we read
5633 * only one element of the array here.
5635 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
5636 eventfd_signal(t
->entries
[i
].eventfd
, 1);
5638 /* Update current_threshold */
5639 t
->current_threshold
= i
- 1;
5644 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
5647 __mem_cgroup_threshold(memcg
, false);
5648 if (do_swap_account
)
5649 __mem_cgroup_threshold(memcg
, true);
5651 memcg
= parent_mem_cgroup(memcg
);
5655 static int compare_thresholds(const void *a
, const void *b
)
5657 const struct mem_cgroup_threshold
*_a
= a
;
5658 const struct mem_cgroup_threshold
*_b
= b
;
5660 if (_a
->threshold
> _b
->threshold
)
5663 if (_a
->threshold
< _b
->threshold
)
5669 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
5671 struct mem_cgroup_eventfd_list
*ev
;
5673 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
5674 eventfd_signal(ev
->eventfd
, 1);
5678 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
5680 struct mem_cgroup
*iter
;
5682 for_each_mem_cgroup_tree(iter
, memcg
)
5683 mem_cgroup_oom_notify_cb(iter
);
5686 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5687 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
5689 struct mem_cgroup_thresholds
*thresholds
;
5690 struct mem_cgroup_threshold_ary
*new;
5691 u64 threshold
, usage
;
5694 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
5698 mutex_lock(&memcg
->thresholds_lock
);
5701 thresholds
= &memcg
->thresholds
;
5702 else if (type
== _MEMSWAP
)
5703 thresholds
= &memcg
->memsw_thresholds
;
5707 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5709 /* Check if a threshold crossed before adding a new one */
5710 if (thresholds
->primary
)
5711 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5713 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
5715 /* Allocate memory for new array of thresholds */
5716 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
5724 /* Copy thresholds (if any) to new array */
5725 if (thresholds
->primary
) {
5726 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
5727 sizeof(struct mem_cgroup_threshold
));
5730 /* Add new threshold */
5731 new->entries
[size
- 1].eventfd
= eventfd
;
5732 new->entries
[size
- 1].threshold
= threshold
;
5734 /* Sort thresholds. Registering of new threshold isn't time-critical */
5735 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
5736 compare_thresholds
, NULL
);
5738 /* Find current threshold */
5739 new->current_threshold
= -1;
5740 for (i
= 0; i
< size
; i
++) {
5741 if (new->entries
[i
].threshold
<= usage
) {
5743 * new->current_threshold will not be used until
5744 * rcu_assign_pointer(), so it's safe to increment
5747 ++new->current_threshold
;
5752 /* Free old spare buffer and save old primary buffer as spare */
5753 kfree(thresholds
->spare
);
5754 thresholds
->spare
= thresholds
->primary
;
5756 rcu_assign_pointer(thresholds
->primary
, new);
5758 /* To be sure that nobody uses thresholds */
5762 mutex_unlock(&memcg
->thresholds_lock
);
5767 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5768 struct eventfd_ctx
*eventfd
, const char *args
)
5770 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
5773 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
5774 struct eventfd_ctx
*eventfd
, const char *args
)
5776 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
5779 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5780 struct eventfd_ctx
*eventfd
, enum res_type type
)
5782 struct mem_cgroup_thresholds
*thresholds
;
5783 struct mem_cgroup_threshold_ary
*new;
5787 mutex_lock(&memcg
->thresholds_lock
);
5789 thresholds
= &memcg
->thresholds
;
5790 else if (type
== _MEMSWAP
)
5791 thresholds
= &memcg
->memsw_thresholds
;
5795 if (!thresholds
->primary
)
5798 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
5800 /* Check if a threshold crossed before removing */
5801 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
5803 /* Calculate new number of threshold */
5805 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
5806 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
5810 new = thresholds
->spare
;
5812 /* Set thresholds array to NULL if we don't have thresholds */
5821 /* Copy thresholds and find current threshold */
5822 new->current_threshold
= -1;
5823 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
5824 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
5827 new->entries
[j
] = thresholds
->primary
->entries
[i
];
5828 if (new->entries
[j
].threshold
<= usage
) {
5830 * new->current_threshold will not be used
5831 * until rcu_assign_pointer(), so it's safe to increment
5834 ++new->current_threshold
;
5840 /* Swap primary and spare array */
5841 thresholds
->spare
= thresholds
->primary
;
5842 /* If all events are unregistered, free the spare array */
5844 kfree(thresholds
->spare
);
5845 thresholds
->spare
= NULL
;
5848 rcu_assign_pointer(thresholds
->primary
, new);
5850 /* To be sure that nobody uses thresholds */
5853 mutex_unlock(&memcg
->thresholds_lock
);
5856 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5857 struct eventfd_ctx
*eventfd
)
5859 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
5862 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
5863 struct eventfd_ctx
*eventfd
)
5865 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
5868 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
5869 struct eventfd_ctx
*eventfd
, const char *args
)
5871 struct mem_cgroup_eventfd_list
*event
;
5873 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
5877 spin_lock(&memcg_oom_lock
);
5879 event
->eventfd
= eventfd
;
5880 list_add(&event
->list
, &memcg
->oom_notify
);
5882 /* already in OOM ? */
5883 if (atomic_read(&memcg
->under_oom
))
5884 eventfd_signal(eventfd
, 1);
5885 spin_unlock(&memcg_oom_lock
);
5890 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
5891 struct eventfd_ctx
*eventfd
)
5893 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
5895 spin_lock(&memcg_oom_lock
);
5897 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
5898 if (ev
->eventfd
== eventfd
) {
5899 list_del(&ev
->list
);
5904 spin_unlock(&memcg_oom_lock
);
5907 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
5909 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
5911 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
5912 seq_printf(sf
, "under_oom %d\n", (bool)atomic_read(&memcg
->under_oom
));
5916 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
5917 struct cftype
*cft
, u64 val
)
5919 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5920 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(&memcg
->css
));
5922 /* cannot set to root cgroup and only 0 and 1 are allowed */
5923 if (!parent
|| !((val
== 0) || (val
== 1)))
5926 mutex_lock(&memcg_create_mutex
);
5927 /* oom-kill-disable is a flag for subhierarchy. */
5928 if ((parent
->use_hierarchy
) || memcg_has_children(memcg
)) {
5929 mutex_unlock(&memcg_create_mutex
);
5932 memcg
->oom_kill_disable
= val
;
5934 memcg_oom_recover(memcg
);
5935 mutex_unlock(&memcg_create_mutex
);
5939 #ifdef CONFIG_MEMCG_KMEM
5940 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5944 memcg
->kmemcg_id
= -1;
5945 ret
= memcg_propagate_kmem(memcg
);
5949 return mem_cgroup_sockets_init(memcg
, ss
);
5952 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
5954 mem_cgroup_sockets_destroy(memcg
);
5957 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
5959 if (!memcg_kmem_is_active(memcg
))
5963 * kmem charges can outlive the cgroup. In the case of slab
5964 * pages, for instance, a page contain objects from various
5965 * processes. As we prevent from taking a reference for every
5966 * such allocation we have to be careful when doing uncharge
5967 * (see memcg_uncharge_kmem) and here during offlining.
5969 * The idea is that that only the _last_ uncharge which sees
5970 * the dead memcg will drop the last reference. An additional
5971 * reference is taken here before the group is marked dead
5972 * which is then paired with css_put during uncharge resp. here.
5974 * Although this might sound strange as this path is called from
5975 * css_offline() when the referencemight have dropped down to 0
5976 * and shouldn't be incremented anymore (css_tryget would fail)
5977 * we do not have other options because of the kmem allocations
5980 css_get(&memcg
->css
);
5982 memcg_kmem_mark_dead(memcg
);
5984 if (res_counter_read_u64(&memcg
->kmem
, RES_USAGE
) != 0)
5987 if (memcg_kmem_test_and_clear_dead(memcg
))
5988 css_put(&memcg
->css
);
5991 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
5996 static void memcg_destroy_kmem(struct mem_cgroup
*memcg
)
6000 static void kmem_cgroup_css_offline(struct mem_cgroup
*memcg
)
6006 * DO NOT USE IN NEW FILES.
6008 * "cgroup.event_control" implementation.
6010 * This is way over-engineered. It tries to support fully configurable
6011 * events for each user. Such level of flexibility is completely
6012 * unnecessary especially in the light of the planned unified hierarchy.
6014 * Please deprecate this and replace with something simpler if at all
6019 * Unregister event and free resources.
6021 * Gets called from workqueue.
6023 static void memcg_event_remove(struct work_struct
*work
)
6025 struct mem_cgroup_event
*event
=
6026 container_of(work
, struct mem_cgroup_event
, remove
);
6027 struct mem_cgroup
*memcg
= event
->memcg
;
6029 remove_wait_queue(event
->wqh
, &event
->wait
);
6031 event
->unregister_event(memcg
, event
->eventfd
);
6033 /* Notify userspace the event is going away. */
6034 eventfd_signal(event
->eventfd
, 1);
6036 eventfd_ctx_put(event
->eventfd
);
6038 css_put(&memcg
->css
);
6042 * Gets called on POLLHUP on eventfd when user closes it.
6044 * Called with wqh->lock held and interrupts disabled.
6046 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
6047 int sync
, void *key
)
6049 struct mem_cgroup_event
*event
=
6050 container_of(wait
, struct mem_cgroup_event
, wait
);
6051 struct mem_cgroup
*memcg
= event
->memcg
;
6052 unsigned long flags
= (unsigned long)key
;
6054 if (flags
& POLLHUP
) {
6056 * If the event has been detached at cgroup removal, we
6057 * can simply return knowing the other side will cleanup
6060 * We can't race against event freeing since the other
6061 * side will require wqh->lock via remove_wait_queue(),
6064 spin_lock(&memcg
->event_list_lock
);
6065 if (!list_empty(&event
->list
)) {
6066 list_del_init(&event
->list
);
6068 * We are in atomic context, but cgroup_event_remove()
6069 * may sleep, so we have to call it in workqueue.
6071 schedule_work(&event
->remove
);
6073 spin_unlock(&memcg
->event_list_lock
);
6079 static void memcg_event_ptable_queue_proc(struct file
*file
,
6080 wait_queue_head_t
*wqh
, poll_table
*pt
)
6082 struct mem_cgroup_event
*event
=
6083 container_of(pt
, struct mem_cgroup_event
, pt
);
6086 add_wait_queue(wqh
, &event
->wait
);
6090 * DO NOT USE IN NEW FILES.
6092 * Parse input and register new cgroup event handler.
6094 * Input must be in format '<event_fd> <control_fd> <args>'.
6095 * Interpretation of args is defined by control file implementation.
6097 static int memcg_write_event_control(struct cgroup_subsys_state
*css
,
6098 struct cftype
*cft
, const char *buffer
)
6100 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6101 struct mem_cgroup_event
*event
;
6102 struct cgroup_subsys_state
*cfile_css
;
6103 unsigned int efd
, cfd
;
6110 efd
= simple_strtoul(buffer
, &endp
, 10);
6115 cfd
= simple_strtoul(buffer
, &endp
, 10);
6116 if ((*endp
!= ' ') && (*endp
!= '\0'))
6120 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
6124 event
->memcg
= memcg
;
6125 INIT_LIST_HEAD(&event
->list
);
6126 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
6127 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
6128 INIT_WORK(&event
->remove
, memcg_event_remove
);
6136 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
6137 if (IS_ERR(event
->eventfd
)) {
6138 ret
= PTR_ERR(event
->eventfd
);
6145 goto out_put_eventfd
;
6148 /* the process need read permission on control file */
6149 /* AV: shouldn't we check that it's been opened for read instead? */
6150 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
6155 * Determine the event callbacks and set them in @event. This used
6156 * to be done via struct cftype but cgroup core no longer knows
6157 * about these events. The following is crude but the whole thing
6158 * is for compatibility anyway.
6160 * DO NOT ADD NEW FILES.
6162 name
= cfile
.file
->f_dentry
->d_name
.name
;
6164 if (!strcmp(name
, "memory.usage_in_bytes")) {
6165 event
->register_event
= mem_cgroup_usage_register_event
;
6166 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
6167 } else if (!strcmp(name
, "memory.oom_control")) {
6168 event
->register_event
= mem_cgroup_oom_register_event
;
6169 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
6170 } else if (!strcmp(name
, "memory.pressure_level")) {
6171 event
->register_event
= vmpressure_register_event
;
6172 event
->unregister_event
= vmpressure_unregister_event
;
6173 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
6174 event
->register_event
= memsw_cgroup_usage_register_event
;
6175 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
6182 * Verify @cfile should belong to @css. Also, remaining events are
6183 * automatically removed on cgroup destruction but the removal is
6184 * asynchronous, so take an extra ref on @css.
6189 cfile_css
= css_from_dir(cfile
.file
->f_dentry
->d_parent
,
6190 &mem_cgroup_subsys
);
6191 if (cfile_css
== css
&& css_tryget(css
))
6198 ret
= event
->register_event(memcg
, event
->eventfd
, buffer
);
6202 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
6204 spin_lock(&memcg
->event_list_lock
);
6205 list_add(&event
->list
, &memcg
->event_list
);
6206 spin_unlock(&memcg
->event_list_lock
);
6218 eventfd_ctx_put(event
->eventfd
);
6227 static struct cftype mem_cgroup_files
[] = {
6229 .name
= "usage_in_bytes",
6230 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
6231 .read_u64
= mem_cgroup_read_u64
,
6234 .name
= "max_usage_in_bytes",
6235 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
6236 .trigger
= mem_cgroup_reset
,
6237 .read_u64
= mem_cgroup_read_u64
,
6240 .name
= "limit_in_bytes",
6241 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
6242 .write_string
= mem_cgroup_write
,
6243 .read_u64
= mem_cgroup_read_u64
,
6246 .name
= "soft_limit_in_bytes",
6247 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
6248 .write_string
= mem_cgroup_write
,
6249 .read_u64
= mem_cgroup_read_u64
,
6253 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
6254 .trigger
= mem_cgroup_reset
,
6255 .read_u64
= mem_cgroup_read_u64
,
6259 .seq_show
= memcg_stat_show
,
6262 .name
= "force_empty",
6263 .trigger
= mem_cgroup_force_empty_write
,
6266 .name
= "use_hierarchy",
6267 .flags
= CFTYPE_INSANE
,
6268 .write_u64
= mem_cgroup_hierarchy_write
,
6269 .read_u64
= mem_cgroup_hierarchy_read
,
6272 .name
= "cgroup.event_control", /* XXX: for compat */
6273 .write_string
= memcg_write_event_control
,
6274 .flags
= CFTYPE_NO_PREFIX
,
6278 .name
= "swappiness",
6279 .read_u64
= mem_cgroup_swappiness_read
,
6280 .write_u64
= mem_cgroup_swappiness_write
,
6283 .name
= "move_charge_at_immigrate",
6284 .read_u64
= mem_cgroup_move_charge_read
,
6285 .write_u64
= mem_cgroup_move_charge_write
,
6288 .name
= "oom_control",
6289 .seq_show
= mem_cgroup_oom_control_read
,
6290 .write_u64
= mem_cgroup_oom_control_write
,
6291 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
6294 .name
= "pressure_level",
6298 .name
= "numa_stat",
6299 .seq_show
= memcg_numa_stat_show
,
6302 #ifdef CONFIG_MEMCG_KMEM
6304 .name
= "kmem.limit_in_bytes",
6305 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
6306 .write_string
= mem_cgroup_write
,
6307 .read_u64
= mem_cgroup_read_u64
,
6310 .name
= "kmem.usage_in_bytes",
6311 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
6312 .read_u64
= mem_cgroup_read_u64
,
6315 .name
= "kmem.failcnt",
6316 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
6317 .trigger
= mem_cgroup_reset
,
6318 .read_u64
= mem_cgroup_read_u64
,
6321 .name
= "kmem.max_usage_in_bytes",
6322 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
6323 .trigger
= mem_cgroup_reset
,
6324 .read_u64
= mem_cgroup_read_u64
,
6326 #ifdef CONFIG_SLABINFO
6328 .name
= "kmem.slabinfo",
6329 .seq_show
= mem_cgroup_slabinfo_read
,
6333 { }, /* terminate */
6336 #ifdef CONFIG_MEMCG_SWAP
6337 static struct cftype memsw_cgroup_files
[] = {
6339 .name
= "memsw.usage_in_bytes",
6340 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6341 .read_u64
= mem_cgroup_read_u64
,
6344 .name
= "memsw.max_usage_in_bytes",
6345 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6346 .trigger
= mem_cgroup_reset
,
6347 .read_u64
= mem_cgroup_read_u64
,
6350 .name
= "memsw.limit_in_bytes",
6351 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6352 .write_string
= mem_cgroup_write
,
6353 .read_u64
= mem_cgroup_read_u64
,
6356 .name
= "memsw.failcnt",
6357 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6358 .trigger
= mem_cgroup_reset
,
6359 .read_u64
= mem_cgroup_read_u64
,
6361 { }, /* terminate */
6364 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6366 struct mem_cgroup_per_node
*pn
;
6367 struct mem_cgroup_per_zone
*mz
;
6368 int zone
, tmp
= node
;
6370 * This routine is called against possible nodes.
6371 * But it's BUG to call kmalloc() against offline node.
6373 * TODO: this routine can waste much memory for nodes which will
6374 * never be onlined. It's better to use memory hotplug callback
6377 if (!node_state(node
, N_NORMAL_MEMORY
))
6379 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
6383 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6384 mz
= &pn
->zoneinfo
[zone
];
6385 lruvec_init(&mz
->lruvec
);
6386 mz
->usage_in_excess
= 0;
6387 mz
->on_tree
= false;
6390 memcg
->nodeinfo
[node
] = pn
;
6394 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
6396 kfree(memcg
->nodeinfo
[node
]);
6399 static struct mem_cgroup
*mem_cgroup_alloc(void)
6401 struct mem_cgroup
*memcg
;
6402 size_t size
= memcg_size();
6404 /* Can be very big if nr_node_ids is very big */
6405 if (size
< PAGE_SIZE
)
6406 memcg
= kzalloc(size
, GFP_KERNEL
);
6408 memcg
= vzalloc(size
);
6413 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
6416 spin_lock_init(&memcg
->pcp_counter_lock
);
6420 if (size
< PAGE_SIZE
)
6428 * At destroying mem_cgroup, references from swap_cgroup can remain.
6429 * (scanning all at force_empty is too costly...)
6431 * Instead of clearing all references at force_empty, we remember
6432 * the number of reference from swap_cgroup and free mem_cgroup when
6433 * it goes down to 0.
6435 * Removal of cgroup itself succeeds regardless of refs from swap.
6438 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
6441 size_t size
= memcg_size();
6443 mem_cgroup_remove_from_trees(memcg
);
6446 free_mem_cgroup_per_zone_info(memcg
, node
);
6448 free_percpu(memcg
->stat
);
6451 * We need to make sure that (at least for now), the jump label
6452 * destruction code runs outside of the cgroup lock. This is because
6453 * get_online_cpus(), which is called from the static_branch update,
6454 * can't be called inside the cgroup_lock. cpusets are the ones
6455 * enforcing this dependency, so if they ever change, we might as well.
6457 * schedule_work() will guarantee this happens. Be careful if you need
6458 * to move this code around, and make sure it is outside
6461 disarm_static_keys(memcg
);
6462 if (size
< PAGE_SIZE
)
6469 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
6471 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
6473 if (!memcg
->res
.parent
)
6475 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
6477 EXPORT_SYMBOL(parent_mem_cgroup
);
6479 static void __init
mem_cgroup_soft_limit_tree_init(void)
6481 struct mem_cgroup_tree_per_node
*rtpn
;
6482 struct mem_cgroup_tree_per_zone
*rtpz
;
6483 int tmp
, node
, zone
;
6485 for_each_node(node
) {
6487 if (!node_state(node
, N_NORMAL_MEMORY
))
6489 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
6492 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6494 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
6495 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
6496 rtpz
->rb_root
= RB_ROOT
;
6497 spin_lock_init(&rtpz
->lock
);
6502 static struct cgroup_subsys_state
* __ref
6503 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
6505 struct mem_cgroup
*memcg
;
6506 long error
= -ENOMEM
;
6509 memcg
= mem_cgroup_alloc();
6511 return ERR_PTR(error
);
6514 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
6518 if (parent_css
== NULL
) {
6519 root_mem_cgroup
= memcg
;
6520 res_counter_init(&memcg
->res
, NULL
);
6521 res_counter_init(&memcg
->memsw
, NULL
);
6522 res_counter_init(&memcg
->kmem
, NULL
);
6525 memcg
->last_scanned_node
= MAX_NUMNODES
;
6526 INIT_LIST_HEAD(&memcg
->oom_notify
);
6527 memcg
->move_charge_at_immigrate
= 0;
6528 mutex_init(&memcg
->thresholds_lock
);
6529 spin_lock_init(&memcg
->move_lock
);
6530 vmpressure_init(&memcg
->vmpressure
);
6531 INIT_LIST_HEAD(&memcg
->event_list
);
6532 spin_lock_init(&memcg
->event_list_lock
);
6537 __mem_cgroup_free(memcg
);
6538 return ERR_PTR(error
);
6542 mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
6544 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6545 struct mem_cgroup
*parent
= mem_cgroup_from_css(css_parent(css
));
6548 if (css
->cgroup
->id
> MEM_CGROUP_ID_MAX
)
6554 mutex_lock(&memcg_create_mutex
);
6556 memcg
->use_hierarchy
= parent
->use_hierarchy
;
6557 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
6558 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
6560 if (parent
->use_hierarchy
) {
6561 res_counter_init(&memcg
->res
, &parent
->res
);
6562 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
6563 res_counter_init(&memcg
->kmem
, &parent
->kmem
);
6566 * No need to take a reference to the parent because cgroup
6567 * core guarantees its existence.
6570 res_counter_init(&memcg
->res
, NULL
);
6571 res_counter_init(&memcg
->memsw
, NULL
);
6572 res_counter_init(&memcg
->kmem
, NULL
);
6574 * Deeper hierachy with use_hierarchy == false doesn't make
6575 * much sense so let cgroup subsystem know about this
6576 * unfortunate state in our controller.
6578 if (parent
!= root_mem_cgroup
)
6579 mem_cgroup_subsys
.broken_hierarchy
= true;
6582 error
= memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
6583 mutex_unlock(&memcg_create_mutex
);
6588 * Announce all parents that a group from their hierarchy is gone.
6590 static void mem_cgroup_invalidate_reclaim_iterators(struct mem_cgroup
*memcg
)
6592 struct mem_cgroup
*parent
= memcg
;
6594 while ((parent
= parent_mem_cgroup(parent
)))
6595 mem_cgroup_iter_invalidate(parent
);
6598 * if the root memcg is not hierarchical we have to check it
6601 if (!root_mem_cgroup
->use_hierarchy
)
6602 mem_cgroup_iter_invalidate(root_mem_cgroup
);
6605 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
6607 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6608 struct mem_cgroup_event
*event
, *tmp
;
6611 * Unregister events and notify userspace.
6612 * Notify userspace about cgroup removing only after rmdir of cgroup
6613 * directory to avoid race between userspace and kernelspace.
6615 spin_lock(&memcg
->event_list_lock
);
6616 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
6617 list_del_init(&event
->list
);
6618 schedule_work(&event
->remove
);
6620 spin_unlock(&memcg
->event_list_lock
);
6622 kmem_cgroup_css_offline(memcg
);
6624 mem_cgroup_invalidate_reclaim_iterators(memcg
);
6625 mem_cgroup_reparent_charges(memcg
);
6626 mem_cgroup_destroy_all_caches(memcg
);
6627 vmpressure_cleanup(&memcg
->vmpressure
);
6630 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
6632 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6634 memcg_destroy_kmem(memcg
);
6635 __mem_cgroup_free(memcg
);
6639 /* Handlers for move charge at task migration. */
6640 #define PRECHARGE_COUNT_AT_ONCE 256
6641 static int mem_cgroup_do_precharge(unsigned long count
)
6644 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6645 struct mem_cgroup
*memcg
= mc
.to
;
6647 if (mem_cgroup_is_root(memcg
)) {
6648 mc
.precharge
+= count
;
6649 /* we don't need css_get for root */
6652 /* try to charge at once */
6654 struct res_counter
*dummy
;
6656 * "memcg" cannot be under rmdir() because we've already checked
6657 * by cgroup_lock_live_cgroup() that it is not removed and we
6658 * are still under the same cgroup_mutex. So we can postpone
6661 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
6663 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
6664 PAGE_SIZE
* count
, &dummy
)) {
6665 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
6668 mc
.precharge
+= count
;
6672 /* fall back to one by one charge */
6674 if (signal_pending(current
)) {
6678 if (!batch_count
--) {
6679 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
6682 ret
= __mem_cgroup_try_charge(NULL
,
6683 GFP_KERNEL
, 1, &memcg
, false);
6685 /* mem_cgroup_clear_mc() will do uncharge later */
6693 * get_mctgt_type - get target type of moving charge
6694 * @vma: the vma the pte to be checked belongs
6695 * @addr: the address corresponding to the pte to be checked
6696 * @ptent: the pte to be checked
6697 * @target: the pointer the target page or swap ent will be stored(can be NULL)
6700 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
6701 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
6702 * move charge. if @target is not NULL, the page is stored in target->page
6703 * with extra refcnt got(Callers should handle it).
6704 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
6705 * target for charge migration. if @target is not NULL, the entry is stored
6708 * Called with pte lock held.
6715 enum mc_target_type
{
6721 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
6722 unsigned long addr
, pte_t ptent
)
6724 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
6726 if (!page
|| !page_mapped(page
))
6728 if (PageAnon(page
)) {
6729 /* we don't move shared anon */
6732 } else if (!move_file())
6733 /* we ignore mapcount for file pages */
6735 if (!get_page_unless_zero(page
))
6742 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6743 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6745 struct page
*page
= NULL
;
6746 swp_entry_t ent
= pte_to_swp_entry(ptent
);
6748 if (!move_anon() || non_swap_entry(ent
))
6751 * Because lookup_swap_cache() updates some statistics counter,
6752 * we call find_get_page() with swapper_space directly.
6754 page
= find_get_page(swap_address_space(ent
), ent
.val
);
6755 if (do_swap_account
)
6756 entry
->val
= ent
.val
;
6761 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
6762 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6768 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
6769 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
6771 struct page
*page
= NULL
;
6772 struct address_space
*mapping
;
6775 if (!vma
->vm_file
) /* anonymous vma */
6780 mapping
= vma
->vm_file
->f_mapping
;
6781 if (pte_none(ptent
))
6782 pgoff
= linear_page_index(vma
, addr
);
6783 else /* pte_file(ptent) is true */
6784 pgoff
= pte_to_pgoff(ptent
);
6786 /* page is moved even if it's not RSS of this task(page-faulted). */
6787 page
= find_get_page(mapping
, pgoff
);
6790 /* shmem/tmpfs may report page out on swap: account for that too. */
6791 if (radix_tree_exceptional_entry(page
)) {
6792 swp_entry_t swap
= radix_to_swp_entry(page
);
6793 if (do_swap_account
)
6795 page
= find_get_page(swap_address_space(swap
), swap
.val
);
6801 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
6802 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
6804 struct page
*page
= NULL
;
6805 struct page_cgroup
*pc
;
6806 enum mc_target_type ret
= MC_TARGET_NONE
;
6807 swp_entry_t ent
= { .val
= 0 };
6809 if (pte_present(ptent
))
6810 page
= mc_handle_present_pte(vma
, addr
, ptent
);
6811 else if (is_swap_pte(ptent
))
6812 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
6813 else if (pte_none(ptent
) || pte_file(ptent
))
6814 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
6816 if (!page
&& !ent
.val
)
6819 pc
= lookup_page_cgroup(page
);
6821 * Do only loose check w/o page_cgroup lock.
6822 * mem_cgroup_move_account() checks the pc is valid or not under
6825 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6826 ret
= MC_TARGET_PAGE
;
6828 target
->page
= page
;
6830 if (!ret
|| !target
)
6833 /* There is a swap entry and a page doesn't exist or isn't charged */
6834 if (ent
.val
&& !ret
&&
6835 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
6836 ret
= MC_TARGET_SWAP
;
6843 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
6845 * We don't consider swapping or file mapped pages because THP does not
6846 * support them for now.
6847 * Caller should make sure that pmd_trans_huge(pmd) is true.
6849 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6850 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6852 struct page
*page
= NULL
;
6853 struct page_cgroup
*pc
;
6854 enum mc_target_type ret
= MC_TARGET_NONE
;
6856 page
= pmd_page(pmd
);
6857 VM_BUG_ON(!page
|| !PageHead(page
));
6860 pc
= lookup_page_cgroup(page
);
6861 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
6862 ret
= MC_TARGET_PAGE
;
6865 target
->page
= page
;
6871 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
6872 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
6874 return MC_TARGET_NONE
;
6878 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
6879 unsigned long addr
, unsigned long end
,
6880 struct mm_walk
*walk
)
6882 struct vm_area_struct
*vma
= walk
->private;
6886 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
6887 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
6888 mc
.precharge
+= HPAGE_PMD_NR
;
6893 if (pmd_trans_unstable(pmd
))
6895 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6896 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
6897 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
6898 mc
.precharge
++; /* increment precharge temporarily */
6899 pte_unmap_unlock(pte
- 1, ptl
);
6905 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
6907 unsigned long precharge
;
6908 struct vm_area_struct
*vma
;
6910 down_read(&mm
->mmap_sem
);
6911 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
6912 struct mm_walk mem_cgroup_count_precharge_walk
= {
6913 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
6917 if (is_vm_hugetlb_page(vma
))
6919 walk_page_range(vma
->vm_start
, vma
->vm_end
,
6920 &mem_cgroup_count_precharge_walk
);
6922 up_read(&mm
->mmap_sem
);
6924 precharge
= mc
.precharge
;
6930 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
6932 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
6934 VM_BUG_ON(mc
.moving_task
);
6935 mc
.moving_task
= current
;
6936 return mem_cgroup_do_precharge(precharge
);
6939 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
6940 static void __mem_cgroup_clear_mc(void)
6942 struct mem_cgroup
*from
= mc
.from
;
6943 struct mem_cgroup
*to
= mc
.to
;
6946 /* we must uncharge all the leftover precharges from mc.to */
6948 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
6952 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
6953 * we must uncharge here.
6955 if (mc
.moved_charge
) {
6956 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
6957 mc
.moved_charge
= 0;
6959 /* we must fixup refcnts and charges */
6960 if (mc
.moved_swap
) {
6961 /* uncharge swap account from the old cgroup */
6962 if (!mem_cgroup_is_root(mc
.from
))
6963 res_counter_uncharge(&mc
.from
->memsw
,
6964 PAGE_SIZE
* mc
.moved_swap
);
6966 for (i
= 0; i
< mc
.moved_swap
; i
++)
6967 css_put(&mc
.from
->css
);
6969 if (!mem_cgroup_is_root(mc
.to
)) {
6971 * we charged both to->res and to->memsw, so we should
6974 res_counter_uncharge(&mc
.to
->res
,
6975 PAGE_SIZE
* mc
.moved_swap
);
6977 /* we've already done css_get(mc.to) */
6980 memcg_oom_recover(from
);
6981 memcg_oom_recover(to
);
6982 wake_up_all(&mc
.waitq
);
6985 static void mem_cgroup_clear_mc(void)
6987 struct mem_cgroup
*from
= mc
.from
;
6990 * we must clear moving_task before waking up waiters at the end of
6993 mc
.moving_task
= NULL
;
6994 __mem_cgroup_clear_mc();
6995 spin_lock(&mc
.lock
);
6998 spin_unlock(&mc
.lock
);
6999 mem_cgroup_end_move(from
);
7002 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7003 struct cgroup_taskset
*tset
)
7005 struct task_struct
*p
= cgroup_taskset_first(tset
);
7007 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7008 unsigned long move_charge_at_immigrate
;
7011 * We are now commited to this value whatever it is. Changes in this
7012 * tunable will only affect upcoming migrations, not the current one.
7013 * So we need to save it, and keep it going.
7015 move_charge_at_immigrate
= memcg
->move_charge_at_immigrate
;
7016 if (move_charge_at_immigrate
) {
7017 struct mm_struct
*mm
;
7018 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
7020 VM_BUG_ON(from
== memcg
);
7022 mm
= get_task_mm(p
);
7025 /* We move charges only when we move a owner of the mm */
7026 if (mm
->owner
== p
) {
7029 VM_BUG_ON(mc
.precharge
);
7030 VM_BUG_ON(mc
.moved_charge
);
7031 VM_BUG_ON(mc
.moved_swap
);
7032 mem_cgroup_start_move(from
);
7033 spin_lock(&mc
.lock
);
7036 mc
.immigrate_flags
= move_charge_at_immigrate
;
7037 spin_unlock(&mc
.lock
);
7038 /* We set mc.moving_task later */
7040 ret
= mem_cgroup_precharge_mc(mm
);
7042 mem_cgroup_clear_mc();
7049 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7050 struct cgroup_taskset
*tset
)
7052 mem_cgroup_clear_mc();
7055 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
7056 unsigned long addr
, unsigned long end
,
7057 struct mm_walk
*walk
)
7060 struct vm_area_struct
*vma
= walk
->private;
7063 enum mc_target_type target_type
;
7064 union mc_target target
;
7066 struct page_cgroup
*pc
;
7069 * We don't take compound_lock() here but no race with splitting thp
7071 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
7072 * under splitting, which means there's no concurrent thp split,
7073 * - if another thread runs into split_huge_page() just after we
7074 * entered this if-block, the thread must wait for page table lock
7075 * to be unlocked in __split_huge_page_splitting(), where the main
7076 * part of thp split is not executed yet.
7078 if (pmd_trans_huge_lock(pmd
, vma
, &ptl
) == 1) {
7079 if (mc
.precharge
< HPAGE_PMD_NR
) {
7083 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
7084 if (target_type
== MC_TARGET_PAGE
) {
7086 if (!isolate_lru_page(page
)) {
7087 pc
= lookup_page_cgroup(page
);
7088 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
7089 pc
, mc
.from
, mc
.to
)) {
7090 mc
.precharge
-= HPAGE_PMD_NR
;
7091 mc
.moved_charge
+= HPAGE_PMD_NR
;
7093 putback_lru_page(page
);
7101 if (pmd_trans_unstable(pmd
))
7104 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
7105 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
7106 pte_t ptent
= *(pte
++);
7112 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
7113 case MC_TARGET_PAGE
:
7115 if (isolate_lru_page(page
))
7117 pc
= lookup_page_cgroup(page
);
7118 if (!mem_cgroup_move_account(page
, 1, pc
,
7121 /* we uncharge from mc.from later. */
7124 putback_lru_page(page
);
7125 put
: /* get_mctgt_type() gets the page */
7128 case MC_TARGET_SWAP
:
7130 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
7132 /* we fixup refcnts and charges later. */
7140 pte_unmap_unlock(pte
- 1, ptl
);
7145 * We have consumed all precharges we got in can_attach().
7146 * We try charge one by one, but don't do any additional
7147 * charges to mc.to if we have failed in charge once in attach()
7150 ret
= mem_cgroup_do_precharge(1);
7158 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
7160 struct vm_area_struct
*vma
;
7162 lru_add_drain_all();
7164 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
7166 * Someone who are holding the mmap_sem might be waiting in
7167 * waitq. So we cancel all extra charges, wake up all waiters,
7168 * and retry. Because we cancel precharges, we might not be able
7169 * to move enough charges, but moving charge is a best-effort
7170 * feature anyway, so it wouldn't be a big problem.
7172 __mem_cgroup_clear_mc();
7176 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
7178 struct mm_walk mem_cgroup_move_charge_walk
= {
7179 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
7183 if (is_vm_hugetlb_page(vma
))
7185 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
7186 &mem_cgroup_move_charge_walk
);
7189 * means we have consumed all precharges and failed in
7190 * doing additional charge. Just abandon here.
7194 up_read(&mm
->mmap_sem
);
7197 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7198 struct cgroup_taskset
*tset
)
7200 struct task_struct
*p
= cgroup_taskset_first(tset
);
7201 struct mm_struct
*mm
= get_task_mm(p
);
7205 mem_cgroup_move_charge(mm
);
7209 mem_cgroup_clear_mc();
7211 #else /* !CONFIG_MMU */
7212 static int mem_cgroup_can_attach(struct cgroup_subsys_state
*css
,
7213 struct cgroup_taskset
*tset
)
7217 static void mem_cgroup_cancel_attach(struct cgroup_subsys_state
*css
,
7218 struct cgroup_taskset
*tset
)
7221 static void mem_cgroup_move_task(struct cgroup_subsys_state
*css
,
7222 struct cgroup_taskset
*tset
)
7228 * Cgroup retains root cgroups across [un]mount cycles making it necessary
7229 * to verify sane_behavior flag on each mount attempt.
7231 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
7234 * use_hierarchy is forced with sane_behavior. cgroup core
7235 * guarantees that @root doesn't have any children, so turning it
7236 * on for the root memcg is enough.
7238 if (cgroup_sane_behavior(root_css
->cgroup
))
7239 mem_cgroup_from_css(root_css
)->use_hierarchy
= true;
7242 struct cgroup_subsys mem_cgroup_subsys
= {
7244 .subsys_id
= mem_cgroup_subsys_id
,
7245 .css_alloc
= mem_cgroup_css_alloc
,
7246 .css_online
= mem_cgroup_css_online
,
7247 .css_offline
= mem_cgroup_css_offline
,
7248 .css_free
= mem_cgroup_css_free
,
7249 .can_attach
= mem_cgroup_can_attach
,
7250 .cancel_attach
= mem_cgroup_cancel_attach
,
7251 .attach
= mem_cgroup_move_task
,
7252 .bind
= mem_cgroup_bind
,
7253 .base_cftypes
= mem_cgroup_files
,
7257 #ifdef CONFIG_MEMCG_SWAP
7258 static int __init
enable_swap_account(char *s
)
7260 if (!strcmp(s
, "1"))
7261 really_do_swap_account
= 1;
7262 else if (!strcmp(s
, "0"))
7263 really_do_swap_account
= 0;
7266 __setup("swapaccount=", enable_swap_account
);
7268 static void __init
memsw_file_init(void)
7270 WARN_ON(cgroup_add_cftypes(&mem_cgroup_subsys
, memsw_cgroup_files
));
7273 static void __init
enable_swap_cgroup(void)
7275 if (!mem_cgroup_disabled() && really_do_swap_account
) {
7276 do_swap_account
= 1;
7282 static void __init
enable_swap_cgroup(void)
7288 * subsys_initcall() for memory controller.
7290 * Some parts like hotcpu_notifier() have to be initialized from this context
7291 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
7292 * everything that doesn't depend on a specific mem_cgroup structure should
7293 * be initialized from here.
7295 static int __init
mem_cgroup_init(void)
7297 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
7298 enable_swap_cgroup();
7299 mem_cgroup_soft_limit_tree_init();
7303 subsys_initcall(mem_cgroup_init
);