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 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License as published by
15 * the Free Software Foundation; either version 2 of the License, or
16 * (at your option) any later version.
18 * This program is distributed in the hope that it will be useful,
19 * but WITHOUT ANY WARRANTY; without even the implied warranty of
20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 * GNU General Public License for more details.
24 #include <linux/res_counter.h>
25 #include <linux/memcontrol.h>
26 #include <linux/cgroup.h>
28 #include <linux/hugetlb.h>
29 #include <linux/pagemap.h>
30 #include <linux/smp.h>
31 #include <linux/page-flags.h>
32 #include <linux/backing-dev.h>
33 #include <linux/bit_spinlock.h>
34 #include <linux/rcupdate.h>
35 #include <linux/limits.h>
36 #include <linux/export.h>
37 #include <linux/mutex.h>
38 #include <linux/rbtree.h>
39 #include <linux/slab.h>
40 #include <linux/swap.h>
41 #include <linux/swapops.h>
42 #include <linux/spinlock.h>
43 #include <linux/eventfd.h>
44 #include <linux/sort.h>
46 #include <linux/seq_file.h>
47 #include <linux/vmalloc.h>
48 #include <linux/mm_inline.h>
49 #include <linux/page_cgroup.h>
50 #include <linux/cpu.h>
51 #include <linux/oom.h>
55 #include <net/tcp_memcontrol.h>
57 #include <asm/uaccess.h>
59 #include <trace/events/vmscan.h>
61 struct cgroup_subsys mem_cgroup_subsys __read_mostly
;
62 #define MEM_CGROUP_RECLAIM_RETRIES 5
63 static struct mem_cgroup
*root_mem_cgroup __read_mostly
;
65 #ifdef CONFIG_MEMCG_SWAP
66 /* Turned on only when memory cgroup is enabled && really_do_swap_account = 1 */
67 int do_swap_account __read_mostly
;
69 /* for remember boot option*/
70 #ifdef CONFIG_MEMCG_SWAP_ENABLED
71 static int really_do_swap_account __initdata
= 1;
73 static int really_do_swap_account __initdata
= 0;
77 #define do_swap_account 0
82 * Statistics for memory cgroup.
84 enum mem_cgroup_stat_index
{
86 * For MEM_CONTAINER_TYPE_ALL, usage = pagecache + rss.
88 MEM_CGROUP_STAT_CACHE
, /* # of pages charged as cache */
89 MEM_CGROUP_STAT_RSS
, /* # of pages charged as anon rss */
90 MEM_CGROUP_STAT_FILE_MAPPED
, /* # of pages charged as file rss */
91 MEM_CGROUP_STAT_SWAP
, /* # of pages, swapped out */
92 MEM_CGROUP_STAT_NSTATS
,
95 static const char * const mem_cgroup_stat_names
[] = {
102 enum mem_cgroup_events_index
{
103 MEM_CGROUP_EVENTS_PGPGIN
, /* # of pages paged in */
104 MEM_CGROUP_EVENTS_PGPGOUT
, /* # of pages paged out */
105 MEM_CGROUP_EVENTS_PGFAULT
, /* # of page-faults */
106 MEM_CGROUP_EVENTS_PGMAJFAULT
, /* # of major page-faults */
107 MEM_CGROUP_EVENTS_NSTATS
,
110 static const char * const mem_cgroup_events_names
[] = {
118 * Per memcg event counter is incremented at every pagein/pageout. With THP,
119 * it will be incremated by the number of pages. This counter is used for
120 * for trigger some periodic events. This is straightforward and better
121 * than using jiffies etc. to handle periodic memcg event.
123 enum mem_cgroup_events_target
{
124 MEM_CGROUP_TARGET_THRESH
,
125 MEM_CGROUP_TARGET_SOFTLIMIT
,
126 MEM_CGROUP_TARGET_NUMAINFO
,
129 #define THRESHOLDS_EVENTS_TARGET 128
130 #define SOFTLIMIT_EVENTS_TARGET 1024
131 #define NUMAINFO_EVENTS_TARGET 1024
133 struct mem_cgroup_stat_cpu
{
134 long count
[MEM_CGROUP_STAT_NSTATS
];
135 unsigned long events
[MEM_CGROUP_EVENTS_NSTATS
];
136 unsigned long nr_page_events
;
137 unsigned long targets
[MEM_CGROUP_NTARGETS
];
140 struct mem_cgroup_reclaim_iter
{
141 /* css_id of the last scanned hierarchy member */
143 /* scan generation, increased every round-trip */
144 unsigned int generation
;
148 * per-zone information in memory controller.
150 struct mem_cgroup_per_zone
{
151 struct lruvec lruvec
;
152 unsigned long lru_size
[NR_LRU_LISTS
];
154 struct mem_cgroup_reclaim_iter reclaim_iter
[DEF_PRIORITY
+ 1];
156 struct rb_node tree_node
; /* RB tree node */
157 unsigned long long usage_in_excess
;/* Set to the value by which */
158 /* the soft limit is exceeded*/
160 struct mem_cgroup
*memcg
; /* Back pointer, we cannot */
161 /* use container_of */
164 struct mem_cgroup_per_node
{
165 struct mem_cgroup_per_zone zoneinfo
[MAX_NR_ZONES
];
168 struct mem_cgroup_lru_info
{
169 struct mem_cgroup_per_node
*nodeinfo
[MAX_NUMNODES
];
173 * Cgroups above their limits are maintained in a RB-Tree, independent of
174 * their hierarchy representation
177 struct mem_cgroup_tree_per_zone
{
178 struct rb_root rb_root
;
182 struct mem_cgroup_tree_per_node
{
183 struct mem_cgroup_tree_per_zone rb_tree_per_zone
[MAX_NR_ZONES
];
186 struct mem_cgroup_tree
{
187 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
190 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
192 struct mem_cgroup_threshold
{
193 struct eventfd_ctx
*eventfd
;
198 struct mem_cgroup_threshold_ary
{
199 /* An array index points to threshold just below or equal to usage. */
200 int current_threshold
;
201 /* Size of entries[] */
203 /* Array of thresholds */
204 struct mem_cgroup_threshold entries
[0];
207 struct mem_cgroup_thresholds
{
208 /* Primary thresholds array */
209 struct mem_cgroup_threshold_ary
*primary
;
211 * Spare threshold array.
212 * This is needed to make mem_cgroup_unregister_event() "never fail".
213 * It must be able to store at least primary->size - 1 entries.
215 struct mem_cgroup_threshold_ary
*spare
;
219 struct mem_cgroup_eventfd_list
{
220 struct list_head list
;
221 struct eventfd_ctx
*eventfd
;
224 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
225 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
228 * The memory controller data structure. The memory controller controls both
229 * page cache and RSS per cgroup. We would eventually like to provide
230 * statistics based on the statistics developed by Rik Van Riel for clock-pro,
231 * to help the administrator determine what knobs to tune.
233 * TODO: Add a water mark for the memory controller. Reclaim will begin when
234 * we hit the water mark. May be even add a low water mark, such that
235 * no reclaim occurs from a cgroup at it's low water mark, this is
236 * a feature that will be implemented much later in the future.
239 struct cgroup_subsys_state css
;
241 * the counter to account for memory usage
243 struct res_counter res
;
247 * the counter to account for mem+swap usage.
249 struct res_counter memsw
;
252 * rcu_freeing is used only when freeing struct mem_cgroup,
253 * so put it into a union to avoid wasting more memory.
254 * It must be disjoint from the css field. It could be
255 * in a union with the res field, but res plays a much
256 * larger part in mem_cgroup life than memsw, and might
257 * be of interest, even at time of free, when debugging.
258 * So share rcu_head with the less interesting memsw.
260 struct rcu_head rcu_freeing
;
262 * We also need some space for a worker in deferred freeing.
263 * By the time we call it, rcu_freeing is no longer in use.
265 struct work_struct work_freeing
;
269 * Per cgroup active and inactive list, similar to the
270 * per zone LRU lists.
272 struct mem_cgroup_lru_info info
;
273 int last_scanned_node
;
275 nodemask_t scan_nodes
;
276 atomic_t numainfo_events
;
277 atomic_t numainfo_updating
;
280 * Should the accounting and control be hierarchical, per subtree?
290 /* OOM-Killer disable */
291 int oom_kill_disable
;
293 /* set when res.limit == memsw.limit */
294 bool memsw_is_minimum
;
296 /* protect arrays of thresholds */
297 struct mutex thresholds_lock
;
299 /* thresholds for memory usage. RCU-protected */
300 struct mem_cgroup_thresholds thresholds
;
302 /* thresholds for mem+swap usage. RCU-protected */
303 struct mem_cgroup_thresholds memsw_thresholds
;
305 /* For oom notifier event fd */
306 struct list_head oom_notify
;
309 * Should we move charges of a task when a task is moved into this
310 * mem_cgroup ? And what type of charges should we move ?
312 unsigned long move_charge_at_immigrate
;
314 * set > 0 if pages under this cgroup are moving to other cgroup.
316 atomic_t moving_account
;
317 /* taken only while moving_account > 0 */
318 spinlock_t move_lock
;
322 struct mem_cgroup_stat_cpu __percpu
*stat
;
324 * used when a cpu is offlined or other synchronizations
325 * See mem_cgroup_read_stat().
327 struct mem_cgroup_stat_cpu nocpu_base
;
328 spinlock_t pcp_counter_lock
;
330 #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_INET)
331 struct tcp_memcontrol tcp_mem
;
335 /* Stuffs for move charges at task migration. */
337 * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
338 * left-shifted bitmap of these types.
341 MOVE_CHARGE_TYPE_ANON
, /* private anonymous page and swap of it */
342 MOVE_CHARGE_TYPE_FILE
, /* file page(including tmpfs) and swap of it */
346 /* "mc" and its members are protected by cgroup_mutex */
347 static struct move_charge_struct
{
348 spinlock_t lock
; /* for from, to */
349 struct mem_cgroup
*from
;
350 struct mem_cgroup
*to
;
351 unsigned long precharge
;
352 unsigned long moved_charge
;
353 unsigned long moved_swap
;
354 struct task_struct
*moving_task
; /* a task moving charges */
355 wait_queue_head_t waitq
; /* a waitq for other context */
357 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
358 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
361 static bool move_anon(void)
363 return test_bit(MOVE_CHARGE_TYPE_ANON
,
364 &mc
.to
->move_charge_at_immigrate
);
367 static bool move_file(void)
369 return test_bit(MOVE_CHARGE_TYPE_FILE
,
370 &mc
.to
->move_charge_at_immigrate
);
374 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
375 * limit reclaim to prevent infinite loops, if they ever occur.
377 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
378 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
381 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
382 MEM_CGROUP_CHARGE_TYPE_ANON
,
383 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
384 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
388 /* for encoding cft->private value on file */
391 #define _OOM_TYPE (2)
392 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
393 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
394 #define MEMFILE_ATTR(val) ((val) & 0xffff)
395 /* Used for OOM nofiier */
396 #define OOM_CONTROL (0)
399 * Reclaim flags for mem_cgroup_hierarchical_reclaim
401 #define MEM_CGROUP_RECLAIM_NOSWAP_BIT 0x0
402 #define MEM_CGROUP_RECLAIM_NOSWAP (1 << MEM_CGROUP_RECLAIM_NOSWAP_BIT)
403 #define MEM_CGROUP_RECLAIM_SHRINK_BIT 0x1
404 #define MEM_CGROUP_RECLAIM_SHRINK (1 << MEM_CGROUP_RECLAIM_SHRINK_BIT)
406 static void mem_cgroup_get(struct mem_cgroup
*memcg
);
407 static void mem_cgroup_put(struct mem_cgroup
*memcg
);
410 struct mem_cgroup
*mem_cgroup_from_css(struct cgroup_subsys_state
*s
)
412 return container_of(s
, struct mem_cgroup
, css
);
415 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
417 return (memcg
== root_mem_cgroup
);
420 /* Writing them here to avoid exposing memcg's inner layout */
421 #if defined(CONFIG_INET) && defined(CONFIG_MEMCG_KMEM)
423 void sock_update_memcg(struct sock
*sk
)
425 if (mem_cgroup_sockets_enabled
) {
426 struct mem_cgroup
*memcg
;
427 struct cg_proto
*cg_proto
;
429 BUG_ON(!sk
->sk_prot
->proto_cgroup
);
431 /* Socket cloning can throw us here with sk_cgrp already
432 * filled. It won't however, necessarily happen from
433 * process context. So the test for root memcg given
434 * the current task's memcg won't help us in this case.
436 * Respecting the original socket's memcg is a better
437 * decision in this case.
440 BUG_ON(mem_cgroup_is_root(sk
->sk_cgrp
->memcg
));
441 mem_cgroup_get(sk
->sk_cgrp
->memcg
);
446 memcg
= mem_cgroup_from_task(current
);
447 cg_proto
= sk
->sk_prot
->proto_cgroup(memcg
);
448 if (!mem_cgroup_is_root(memcg
) && memcg_proto_active(cg_proto
)) {
449 mem_cgroup_get(memcg
);
450 sk
->sk_cgrp
= cg_proto
;
455 EXPORT_SYMBOL(sock_update_memcg
);
457 void sock_release_memcg(struct sock
*sk
)
459 if (mem_cgroup_sockets_enabled
&& sk
->sk_cgrp
) {
460 struct mem_cgroup
*memcg
;
461 WARN_ON(!sk
->sk_cgrp
->memcg
);
462 memcg
= sk
->sk_cgrp
->memcg
;
463 mem_cgroup_put(memcg
);
467 struct cg_proto
*tcp_proto_cgroup(struct mem_cgroup
*memcg
)
469 if (!memcg
|| mem_cgroup_is_root(memcg
))
472 return &memcg
->tcp_mem
.cg_proto
;
474 EXPORT_SYMBOL(tcp_proto_cgroup
);
476 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
478 if (!memcg_proto_activated(&memcg
->tcp_mem
.cg_proto
))
480 static_key_slow_dec(&memcg_socket_limit_enabled
);
483 static void disarm_sock_keys(struct mem_cgroup
*memcg
)
488 static void drain_all_stock_async(struct mem_cgroup
*memcg
);
490 static struct mem_cgroup_per_zone
*
491 mem_cgroup_zoneinfo(struct mem_cgroup
*memcg
, int nid
, int zid
)
493 return &memcg
->info
.nodeinfo
[nid
]->zoneinfo
[zid
];
496 struct cgroup_subsys_state
*mem_cgroup_css(struct mem_cgroup
*memcg
)
501 static struct mem_cgroup_per_zone
*
502 page_cgroup_zoneinfo(struct mem_cgroup
*memcg
, struct page
*page
)
504 int nid
= page_to_nid(page
);
505 int zid
= page_zonenum(page
);
507 return mem_cgroup_zoneinfo(memcg
, nid
, zid
);
510 static struct mem_cgroup_tree_per_zone
*
511 soft_limit_tree_node_zone(int nid
, int zid
)
513 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
516 static struct mem_cgroup_tree_per_zone
*
517 soft_limit_tree_from_page(struct page
*page
)
519 int nid
= page_to_nid(page
);
520 int zid
= page_zonenum(page
);
522 return &soft_limit_tree
.rb_tree_per_node
[nid
]->rb_tree_per_zone
[zid
];
526 __mem_cgroup_insert_exceeded(struct mem_cgroup
*memcg
,
527 struct mem_cgroup_per_zone
*mz
,
528 struct mem_cgroup_tree_per_zone
*mctz
,
529 unsigned long long new_usage_in_excess
)
531 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
532 struct rb_node
*parent
= NULL
;
533 struct mem_cgroup_per_zone
*mz_node
;
538 mz
->usage_in_excess
= new_usage_in_excess
;
539 if (!mz
->usage_in_excess
)
543 mz_node
= rb_entry(parent
, struct mem_cgroup_per_zone
,
545 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
548 * We can't avoid mem cgroups that are over their soft
549 * limit by the same amount
551 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
554 rb_link_node(&mz
->tree_node
, parent
, p
);
555 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
560 __mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
561 struct mem_cgroup_per_zone
*mz
,
562 struct mem_cgroup_tree_per_zone
*mctz
)
566 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
571 mem_cgroup_remove_exceeded(struct mem_cgroup
*memcg
,
572 struct mem_cgroup_per_zone
*mz
,
573 struct mem_cgroup_tree_per_zone
*mctz
)
575 spin_lock(&mctz
->lock
);
576 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
577 spin_unlock(&mctz
->lock
);
581 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
583 unsigned long long excess
;
584 struct mem_cgroup_per_zone
*mz
;
585 struct mem_cgroup_tree_per_zone
*mctz
;
586 int nid
= page_to_nid(page
);
587 int zid
= page_zonenum(page
);
588 mctz
= soft_limit_tree_from_page(page
);
591 * Necessary to update all ancestors when hierarchy is used.
592 * because their event counter is not touched.
594 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
595 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
596 excess
= res_counter_soft_limit_excess(&memcg
->res
);
598 * We have to update the tree if mz is on RB-tree or
599 * mem is over its softlimit.
601 if (excess
|| mz
->on_tree
) {
602 spin_lock(&mctz
->lock
);
603 /* if on-tree, remove it */
605 __mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
607 * Insert again. mz->usage_in_excess will be updated.
608 * If excess is 0, no tree ops.
610 __mem_cgroup_insert_exceeded(memcg
, mz
, mctz
, excess
);
611 spin_unlock(&mctz
->lock
);
616 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
619 struct mem_cgroup_per_zone
*mz
;
620 struct mem_cgroup_tree_per_zone
*mctz
;
622 for_each_node(node
) {
623 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
624 mz
= mem_cgroup_zoneinfo(memcg
, node
, zone
);
625 mctz
= soft_limit_tree_node_zone(node
, zone
);
626 mem_cgroup_remove_exceeded(memcg
, mz
, mctz
);
631 static struct mem_cgroup_per_zone
*
632 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
634 struct rb_node
*rightmost
= NULL
;
635 struct mem_cgroup_per_zone
*mz
;
639 rightmost
= rb_last(&mctz
->rb_root
);
641 goto done
; /* Nothing to reclaim from */
643 mz
= rb_entry(rightmost
, struct mem_cgroup_per_zone
, tree_node
);
645 * Remove the node now but someone else can add it back,
646 * we will to add it back at the end of reclaim to its correct
647 * position in the tree.
649 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
650 if (!res_counter_soft_limit_excess(&mz
->memcg
->res
) ||
651 !css_tryget(&mz
->memcg
->css
))
657 static struct mem_cgroup_per_zone
*
658 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_zone
*mctz
)
660 struct mem_cgroup_per_zone
*mz
;
662 spin_lock(&mctz
->lock
);
663 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
664 spin_unlock(&mctz
->lock
);
669 * Implementation Note: reading percpu statistics for memcg.
671 * Both of vmstat[] and percpu_counter has threshold and do periodic
672 * synchronization to implement "quick" read. There are trade-off between
673 * reading cost and precision of value. Then, we may have a chance to implement
674 * a periodic synchronizion of counter in memcg's counter.
676 * But this _read() function is used for user interface now. The user accounts
677 * memory usage by memory cgroup and he _always_ requires exact value because
678 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
679 * have to visit all online cpus and make sum. So, for now, unnecessary
680 * synchronization is not implemented. (just implemented for cpu hotplug)
682 * If there are kernel internal actions which can make use of some not-exact
683 * value, and reading all cpu value can be performance bottleneck in some
684 * common workload, threashold and synchonization as vmstat[] should be
687 static long mem_cgroup_read_stat(struct mem_cgroup
*memcg
,
688 enum mem_cgroup_stat_index idx
)
694 for_each_online_cpu(cpu
)
695 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
696 #ifdef CONFIG_HOTPLUG_CPU
697 spin_lock(&memcg
->pcp_counter_lock
);
698 val
+= memcg
->nocpu_base
.count
[idx
];
699 spin_unlock(&memcg
->pcp_counter_lock
);
705 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
708 int val
= (charge
) ? 1 : -1;
709 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
712 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
713 enum mem_cgroup_events_index idx
)
715 unsigned long val
= 0;
718 for_each_online_cpu(cpu
)
719 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
720 #ifdef CONFIG_HOTPLUG_CPU
721 spin_lock(&memcg
->pcp_counter_lock
);
722 val
+= memcg
->nocpu_base
.events
[idx
];
723 spin_unlock(&memcg
->pcp_counter_lock
);
728 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
729 bool anon
, int nr_pages
)
734 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
735 * counted as CACHE even if it's on ANON LRU.
738 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
741 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
744 /* pagein of a big page is an event. So, ignore page size */
746 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
748 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
749 nr_pages
= -nr_pages
; /* for event */
752 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
758 mem_cgroup_get_lru_size(struct lruvec
*lruvec
, enum lru_list lru
)
760 struct mem_cgroup_per_zone
*mz
;
762 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
763 return mz
->lru_size
[lru
];
767 mem_cgroup_zone_nr_lru_pages(struct mem_cgroup
*memcg
, int nid
, int zid
,
768 unsigned int lru_mask
)
770 struct mem_cgroup_per_zone
*mz
;
772 unsigned long ret
= 0;
774 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
777 if (BIT(lru
) & lru_mask
)
778 ret
+= mz
->lru_size
[lru
];
784 mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
785 int nid
, unsigned int lru_mask
)
790 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++)
791 total
+= mem_cgroup_zone_nr_lru_pages(memcg
,
797 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
798 unsigned int lru_mask
)
803 for_each_node_state(nid
, N_HIGH_MEMORY
)
804 total
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
808 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
809 enum mem_cgroup_events_target target
)
811 unsigned long val
, next
;
813 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
814 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
815 /* from time_after() in jiffies.h */
816 if ((long)next
- (long)val
< 0) {
818 case MEM_CGROUP_TARGET_THRESH
:
819 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
821 case MEM_CGROUP_TARGET_SOFTLIMIT
:
822 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
824 case MEM_CGROUP_TARGET_NUMAINFO
:
825 next
= val
+ NUMAINFO_EVENTS_TARGET
;
830 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
837 * Check events in order.
840 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
843 /* threshold event is triggered in finer grain than soft limit */
844 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
845 MEM_CGROUP_TARGET_THRESH
))) {
847 bool do_numainfo __maybe_unused
;
849 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
850 MEM_CGROUP_TARGET_SOFTLIMIT
);
852 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
853 MEM_CGROUP_TARGET_NUMAINFO
);
857 mem_cgroup_threshold(memcg
);
858 if (unlikely(do_softlimit
))
859 mem_cgroup_update_tree(memcg
, page
);
861 if (unlikely(do_numainfo
))
862 atomic_inc(&memcg
->numainfo_events
);
868 struct mem_cgroup
*mem_cgroup_from_cont(struct cgroup
*cont
)
870 return mem_cgroup_from_css(
871 cgroup_subsys_state(cont
, mem_cgroup_subsys_id
));
874 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
877 * mm_update_next_owner() may clear mm->owner to NULL
878 * if it races with swapoff, page migration, etc.
879 * So this can be called with p == NULL.
884 return mem_cgroup_from_css(task_subsys_state(p
, mem_cgroup_subsys_id
));
887 struct mem_cgroup
*try_get_mem_cgroup_from_mm(struct mm_struct
*mm
)
889 struct mem_cgroup
*memcg
= NULL
;
894 * Because we have no locks, mm->owner's may be being moved to other
895 * cgroup. We use css_tryget() here even if this looks
896 * pessimistic (rather than adding locks here).
900 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
901 if (unlikely(!memcg
))
903 } while (!css_tryget(&memcg
->css
));
909 * mem_cgroup_iter - iterate over memory cgroup hierarchy
910 * @root: hierarchy root
911 * @prev: previously returned memcg, NULL on first invocation
912 * @reclaim: cookie for shared reclaim walks, NULL for full walks
914 * Returns references to children of the hierarchy below @root, or
915 * @root itself, or %NULL after a full round-trip.
917 * Caller must pass the return value in @prev on subsequent
918 * invocations for reference counting, or use mem_cgroup_iter_break()
919 * to cancel a hierarchy walk before the round-trip is complete.
921 * Reclaimers can specify a zone and a priority level in @reclaim to
922 * divide up the memcgs in the hierarchy among all concurrent
923 * reclaimers operating on the same zone and priority.
925 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
926 struct mem_cgroup
*prev
,
927 struct mem_cgroup_reclaim_cookie
*reclaim
)
929 struct mem_cgroup
*memcg
= NULL
;
932 if (mem_cgroup_disabled())
936 root
= root_mem_cgroup
;
938 if (prev
&& !reclaim
)
939 id
= css_id(&prev
->css
);
941 if (prev
&& prev
!= root
)
944 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
951 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
952 struct cgroup_subsys_state
*css
;
955 int nid
= zone_to_nid(reclaim
->zone
);
956 int zid
= zone_idx(reclaim
->zone
);
957 struct mem_cgroup_per_zone
*mz
;
959 mz
= mem_cgroup_zoneinfo(root
, nid
, zid
);
960 iter
= &mz
->reclaim_iter
[reclaim
->priority
];
961 if (prev
&& reclaim
->generation
!= iter
->generation
)
967 css
= css_get_next(&mem_cgroup_subsys
, id
+ 1, &root
->css
, &id
);
969 if (css
== &root
->css
|| css_tryget(css
))
970 memcg
= mem_cgroup_from_css(css
);
979 else if (!prev
&& memcg
)
980 reclaim
->generation
= iter
->generation
;
990 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
991 * @root: hierarchy root
992 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
994 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
995 struct mem_cgroup
*prev
)
998 root
= root_mem_cgroup
;
999 if (prev
&& prev
!= root
)
1000 css_put(&prev
->css
);
1004 * Iteration constructs for visiting all cgroups (under a tree). If
1005 * loops are exited prematurely (break), mem_cgroup_iter_break() must
1006 * be used for reference counting.
1008 #define for_each_mem_cgroup_tree(iter, root) \
1009 for (iter = mem_cgroup_iter(root, NULL, NULL); \
1011 iter = mem_cgroup_iter(root, iter, NULL))
1013 #define for_each_mem_cgroup(iter) \
1014 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
1016 iter = mem_cgroup_iter(NULL, iter, NULL))
1018 void mem_cgroup_count_vm_event(struct mm_struct
*mm
, enum vm_event_item idx
)
1020 struct mem_cgroup
*memcg
;
1026 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
1027 if (unlikely(!memcg
))
1032 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGFAULT
]);
1035 this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
1043 EXPORT_SYMBOL(mem_cgroup_count_vm_event
);
1046 * mem_cgroup_zone_lruvec - get the lru list vector for a zone and memcg
1047 * @zone: zone of the wanted lruvec
1048 * @memcg: memcg of the wanted lruvec
1050 * Returns the lru list vector holding pages for the given @zone and
1051 * @mem. This can be the global zone lruvec, if the memory controller
1054 struct lruvec
*mem_cgroup_zone_lruvec(struct zone
*zone
,
1055 struct mem_cgroup
*memcg
)
1057 struct mem_cgroup_per_zone
*mz
;
1058 struct lruvec
*lruvec
;
1060 if (mem_cgroup_disabled()) {
1061 lruvec
= &zone
->lruvec
;
1065 mz
= mem_cgroup_zoneinfo(memcg
, zone_to_nid(zone
), zone_idx(zone
));
1066 lruvec
= &mz
->lruvec
;
1069 * Since a node can be onlined after the mem_cgroup was created,
1070 * we have to be prepared to initialize lruvec->zone here;
1071 * and if offlined then reonlined, we need to reinitialize it.
1073 if (unlikely(lruvec
->zone
!= zone
))
1074 lruvec
->zone
= zone
;
1079 * Following LRU functions are allowed to be used without PCG_LOCK.
1080 * Operations are called by routine of global LRU independently from memcg.
1081 * What we have to take care of here is validness of pc->mem_cgroup.
1083 * Changes to pc->mem_cgroup happens when
1086 * In typical case, "charge" is done before add-to-lru. Exception is SwapCache.
1087 * It is added to LRU before charge.
1088 * If PCG_USED bit is not set, page_cgroup is not added to this private LRU.
1089 * When moving account, the page is not on LRU. It's isolated.
1093 * mem_cgroup_page_lruvec - return lruvec for adding an lru page
1095 * @zone: zone of the page
1097 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct zone
*zone
)
1099 struct mem_cgroup_per_zone
*mz
;
1100 struct mem_cgroup
*memcg
;
1101 struct page_cgroup
*pc
;
1102 struct lruvec
*lruvec
;
1104 if (mem_cgroup_disabled()) {
1105 lruvec
= &zone
->lruvec
;
1109 pc
= lookup_page_cgroup(page
);
1110 memcg
= pc
->mem_cgroup
;
1113 * Surreptitiously switch any uncharged offlist page to root:
1114 * an uncharged page off lru does nothing to secure
1115 * its former mem_cgroup from sudden removal.
1117 * Our caller holds lru_lock, and PageCgroupUsed is updated
1118 * under page_cgroup lock: between them, they make all uses
1119 * of pc->mem_cgroup safe.
1121 if (!PageLRU(page
) && !PageCgroupUsed(pc
) && memcg
!= root_mem_cgroup
)
1122 pc
->mem_cgroup
= memcg
= root_mem_cgroup
;
1124 mz
= page_cgroup_zoneinfo(memcg
, page
);
1125 lruvec
= &mz
->lruvec
;
1128 * Since a node can be onlined after the mem_cgroup was created,
1129 * we have to be prepared to initialize lruvec->zone here;
1130 * and if offlined then reonlined, we need to reinitialize it.
1132 if (unlikely(lruvec
->zone
!= zone
))
1133 lruvec
->zone
= zone
;
1138 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1139 * @lruvec: mem_cgroup per zone lru vector
1140 * @lru: index of lru list the page is sitting on
1141 * @nr_pages: positive when adding or negative when removing
1143 * This function must be called when a page is added to or removed from an
1146 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1149 struct mem_cgroup_per_zone
*mz
;
1150 unsigned long *lru_size
;
1152 if (mem_cgroup_disabled())
1155 mz
= container_of(lruvec
, struct mem_cgroup_per_zone
, lruvec
);
1156 lru_size
= mz
->lru_size
+ lru
;
1157 *lru_size
+= nr_pages
;
1158 VM_BUG_ON((long)(*lru_size
) < 0);
1162 * Checks whether given mem is same or in the root_mem_cgroup's
1165 bool __mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1166 struct mem_cgroup
*memcg
)
1168 if (root_memcg
== memcg
)
1170 if (!root_memcg
->use_hierarchy
|| !memcg
)
1172 return css_is_ancestor(&memcg
->css
, &root_memcg
->css
);
1175 static bool mem_cgroup_same_or_subtree(const struct mem_cgroup
*root_memcg
,
1176 struct mem_cgroup
*memcg
)
1181 ret
= __mem_cgroup_same_or_subtree(root_memcg
, memcg
);
1186 int task_in_mem_cgroup(struct task_struct
*task
, const struct mem_cgroup
*memcg
)
1189 struct mem_cgroup
*curr
= NULL
;
1190 struct task_struct
*p
;
1192 p
= find_lock_task_mm(task
);
1194 curr
= try_get_mem_cgroup_from_mm(p
->mm
);
1198 * All threads may have already detached their mm's, but the oom
1199 * killer still needs to detect if they have already been oom
1200 * killed to prevent needlessly killing additional tasks.
1203 curr
= mem_cgroup_from_task(task
);
1205 css_get(&curr
->css
);
1211 * We should check use_hierarchy of "memcg" not "curr". Because checking
1212 * use_hierarchy of "curr" here make this function true if hierarchy is
1213 * enabled in "curr" and "curr" is a child of "memcg" in *cgroup*
1214 * hierarchy(even if use_hierarchy is disabled in "memcg").
1216 ret
= mem_cgroup_same_or_subtree(memcg
, curr
);
1217 css_put(&curr
->css
);
1221 int mem_cgroup_inactive_anon_is_low(struct lruvec
*lruvec
)
1223 unsigned long inactive_ratio
;
1224 unsigned long inactive
;
1225 unsigned long active
;
1228 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_ANON
);
1229 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_ANON
);
1231 gb
= (inactive
+ active
) >> (30 - PAGE_SHIFT
);
1233 inactive_ratio
= int_sqrt(10 * gb
);
1237 return inactive
* inactive_ratio
< active
;
1240 int mem_cgroup_inactive_file_is_low(struct lruvec
*lruvec
)
1242 unsigned long active
;
1243 unsigned long inactive
;
1245 inactive
= mem_cgroup_get_lru_size(lruvec
, LRU_INACTIVE_FILE
);
1246 active
= mem_cgroup_get_lru_size(lruvec
, LRU_ACTIVE_FILE
);
1248 return (active
> inactive
);
1251 #define mem_cgroup_from_res_counter(counter, member) \
1252 container_of(counter, struct mem_cgroup, member)
1255 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1256 * @memcg: the memory cgroup
1258 * Returns the maximum amount of memory @mem can be charged with, in
1261 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1263 unsigned long long margin
;
1265 margin
= res_counter_margin(&memcg
->res
);
1266 if (do_swap_account
)
1267 margin
= min(margin
, res_counter_margin(&memcg
->memsw
));
1268 return margin
>> PAGE_SHIFT
;
1271 int mem_cgroup_swappiness(struct mem_cgroup
*memcg
)
1273 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
1276 if (cgrp
->parent
== NULL
)
1277 return vm_swappiness
;
1279 return memcg
->swappiness
;
1283 * memcg->moving_account is used for checking possibility that some thread is
1284 * calling move_account(). When a thread on CPU-A starts moving pages under
1285 * a memcg, other threads should check memcg->moving_account under
1286 * rcu_read_lock(), like this:
1290 * memcg->moving_account+1 if (memcg->mocing_account)
1292 * synchronize_rcu() update something.
1297 /* for quick checking without looking up memcg */
1298 atomic_t memcg_moving __read_mostly
;
1300 static void mem_cgroup_start_move(struct mem_cgroup
*memcg
)
1302 atomic_inc(&memcg_moving
);
1303 atomic_inc(&memcg
->moving_account
);
1307 static void mem_cgroup_end_move(struct mem_cgroup
*memcg
)
1310 * Now, mem_cgroup_clear_mc() may call this function with NULL.
1311 * We check NULL in callee rather than caller.
1314 atomic_dec(&memcg_moving
);
1315 atomic_dec(&memcg
->moving_account
);
1320 * 2 routines for checking "mem" is under move_account() or not.
1322 * mem_cgroup_stolen() - checking whether a cgroup is mc.from or not. This
1323 * is used for avoiding races in accounting. If true,
1324 * pc->mem_cgroup may be overwritten.
1326 * mem_cgroup_under_move() - checking a cgroup is mc.from or mc.to or
1327 * under hierarchy of moving cgroups. This is for
1328 * waiting at hith-memory prressure caused by "move".
1331 static bool mem_cgroup_stolen(struct mem_cgroup
*memcg
)
1333 VM_BUG_ON(!rcu_read_lock_held());
1334 return atomic_read(&memcg
->moving_account
) > 0;
1337 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1339 struct mem_cgroup
*from
;
1340 struct mem_cgroup
*to
;
1343 * Unlike task_move routines, we access mc.to, mc.from not under
1344 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1346 spin_lock(&mc
.lock
);
1352 ret
= mem_cgroup_same_or_subtree(memcg
, from
)
1353 || mem_cgroup_same_or_subtree(memcg
, to
);
1355 spin_unlock(&mc
.lock
);
1359 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1361 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1362 if (mem_cgroup_under_move(memcg
)) {
1364 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1365 /* moving charge context might have finished. */
1368 finish_wait(&mc
.waitq
, &wait
);
1376 * Take this lock when
1377 * - a code tries to modify page's memcg while it's USED.
1378 * - a code tries to modify page state accounting in a memcg.
1379 * see mem_cgroup_stolen(), too.
1381 static void move_lock_mem_cgroup(struct mem_cgroup
*memcg
,
1382 unsigned long *flags
)
1384 spin_lock_irqsave(&memcg
->move_lock
, *flags
);
1387 static void move_unlock_mem_cgroup(struct mem_cgroup
*memcg
,
1388 unsigned long *flags
)
1390 spin_unlock_irqrestore(&memcg
->move_lock
, *flags
);
1394 * mem_cgroup_print_oom_info: Called from OOM with tasklist_lock held in read mode.
1395 * @memcg: The memory cgroup that went over limit
1396 * @p: Task that is going to be killed
1398 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1401 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1403 struct cgroup
*task_cgrp
;
1404 struct cgroup
*mem_cgrp
;
1406 * Need a buffer in BSS, can't rely on allocations. The code relies
1407 * on the assumption that OOM is serialized for memory controller.
1408 * If this assumption is broken, revisit this code.
1410 static char memcg_name
[PATH_MAX
];
1418 mem_cgrp
= memcg
->css
.cgroup
;
1419 task_cgrp
= task_cgroup(p
, mem_cgroup_subsys_id
);
1421 ret
= cgroup_path(task_cgrp
, memcg_name
, PATH_MAX
);
1424 * Unfortunately, we are unable to convert to a useful name
1425 * But we'll still print out the usage information
1432 printk(KERN_INFO
"Task in %s killed", memcg_name
);
1435 ret
= cgroup_path(mem_cgrp
, memcg_name
, PATH_MAX
);
1443 * Continues from above, so we don't need an KERN_ level
1445 printk(KERN_CONT
" as a result of limit of %s\n", memcg_name
);
1448 printk(KERN_INFO
"memory: usage %llukB, limit %llukB, failcnt %llu\n",
1449 res_counter_read_u64(&memcg
->res
, RES_USAGE
) >> 10,
1450 res_counter_read_u64(&memcg
->res
, RES_LIMIT
) >> 10,
1451 res_counter_read_u64(&memcg
->res
, RES_FAILCNT
));
1452 printk(KERN_INFO
"memory+swap: usage %llukB, limit %llukB, "
1454 res_counter_read_u64(&memcg
->memsw
, RES_USAGE
) >> 10,
1455 res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
) >> 10,
1456 res_counter_read_u64(&memcg
->memsw
, RES_FAILCNT
));
1460 * This function returns the number of memcg under hierarchy tree. Returns
1461 * 1(self count) if no children.
1463 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1466 struct mem_cgroup
*iter
;
1468 for_each_mem_cgroup_tree(iter
, memcg
)
1474 * Return the memory (and swap, if configured) limit for a memcg.
1476 static u64
mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1480 limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
1483 * Do not consider swap space if we cannot swap due to swappiness
1485 if (mem_cgroup_swappiness(memcg
)) {
1488 limit
+= total_swap_pages
<< PAGE_SHIFT
;
1489 memsw
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
1492 * If memsw is finite and limits the amount of swap space
1493 * available to this memcg, return that limit.
1495 limit
= min(limit
, memsw
);
1501 static void mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1504 struct mem_cgroup
*iter
;
1505 unsigned long chosen_points
= 0;
1506 unsigned long totalpages
;
1507 unsigned int points
= 0;
1508 struct task_struct
*chosen
= NULL
;
1511 * If current has a pending SIGKILL, then automatically select it. The
1512 * goal is to allow it to allocate so that it may quickly exit and free
1515 if (fatal_signal_pending(current
)) {
1516 set_thread_flag(TIF_MEMDIE
);
1520 check_panic_on_oom(CONSTRAINT_MEMCG
, gfp_mask
, order
, NULL
);
1521 totalpages
= mem_cgroup_get_limit(memcg
) >> PAGE_SHIFT
? : 1;
1522 for_each_mem_cgroup_tree(iter
, memcg
) {
1523 struct cgroup
*cgroup
= iter
->css
.cgroup
;
1524 struct cgroup_iter it
;
1525 struct task_struct
*task
;
1527 cgroup_iter_start(cgroup
, &it
);
1528 while ((task
= cgroup_iter_next(cgroup
, &it
))) {
1529 switch (oom_scan_process_thread(task
, totalpages
, NULL
,
1531 case OOM_SCAN_SELECT
:
1533 put_task_struct(chosen
);
1535 chosen_points
= ULONG_MAX
;
1536 get_task_struct(chosen
);
1538 case OOM_SCAN_CONTINUE
:
1540 case OOM_SCAN_ABORT
:
1541 cgroup_iter_end(cgroup
, &it
);
1542 mem_cgroup_iter_break(memcg
, iter
);
1544 put_task_struct(chosen
);
1549 points
= oom_badness(task
, memcg
, NULL
, totalpages
);
1550 if (points
> chosen_points
) {
1552 put_task_struct(chosen
);
1554 chosen_points
= points
;
1555 get_task_struct(chosen
);
1558 cgroup_iter_end(cgroup
, &it
);
1563 points
= chosen_points
* 1000 / totalpages
;
1564 oom_kill_process(chosen
, gfp_mask
, order
, points
, totalpages
, memcg
,
1565 NULL
, "Memory cgroup out of memory");
1568 static unsigned long mem_cgroup_reclaim(struct mem_cgroup
*memcg
,
1570 unsigned long flags
)
1572 unsigned long total
= 0;
1573 bool noswap
= false;
1576 if (flags
& MEM_CGROUP_RECLAIM_NOSWAP
)
1578 if (!(flags
& MEM_CGROUP_RECLAIM_SHRINK
) && memcg
->memsw_is_minimum
)
1581 for (loop
= 0; loop
< MEM_CGROUP_MAX_RECLAIM_LOOPS
; loop
++) {
1583 drain_all_stock_async(memcg
);
1584 total
+= try_to_free_mem_cgroup_pages(memcg
, gfp_mask
, noswap
);
1586 * Allow limit shrinkers, which are triggered directly
1587 * by userspace, to catch signals and stop reclaim
1588 * after minimal progress, regardless of the margin.
1590 if (total
&& (flags
& MEM_CGROUP_RECLAIM_SHRINK
))
1592 if (mem_cgroup_margin(memcg
))
1595 * If nothing was reclaimed after two attempts, there
1596 * may be no reclaimable pages in this hierarchy.
1605 * test_mem_cgroup_node_reclaimable
1606 * @memcg: the target memcg
1607 * @nid: the node ID to be checked.
1608 * @noswap : specify true here if the user wants flle only information.
1610 * This function returns whether the specified memcg contains any
1611 * reclaimable pages on a node. Returns true if there are any reclaimable
1612 * pages in the node.
1614 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1615 int nid
, bool noswap
)
1617 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1619 if (noswap
|| !total_swap_pages
)
1621 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1626 #if MAX_NUMNODES > 1
1629 * Always updating the nodemask is not very good - even if we have an empty
1630 * list or the wrong list here, we can start from some node and traverse all
1631 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1634 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1638 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1639 * pagein/pageout changes since the last update.
1641 if (!atomic_read(&memcg
->numainfo_events
))
1643 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1646 /* make a nodemask where this memcg uses memory from */
1647 memcg
->scan_nodes
= node_states
[N_HIGH_MEMORY
];
1649 for_each_node_mask(nid
, node_states
[N_HIGH_MEMORY
]) {
1651 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1652 node_clear(nid
, memcg
->scan_nodes
);
1655 atomic_set(&memcg
->numainfo_events
, 0);
1656 atomic_set(&memcg
->numainfo_updating
, 0);
1660 * Selecting a node where we start reclaim from. Because what we need is just
1661 * reducing usage counter, start from anywhere is O,K. Considering
1662 * memory reclaim from current node, there are pros. and cons.
1664 * Freeing memory from current node means freeing memory from a node which
1665 * we'll use or we've used. So, it may make LRU bad. And if several threads
1666 * hit limits, it will see a contention on a node. But freeing from remote
1667 * node means more costs for memory reclaim because of memory latency.
1669 * Now, we use round-robin. Better algorithm is welcomed.
1671 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1675 mem_cgroup_may_update_nodemask(memcg
);
1676 node
= memcg
->last_scanned_node
;
1678 node
= next_node(node
, memcg
->scan_nodes
);
1679 if (node
== MAX_NUMNODES
)
1680 node
= first_node(memcg
->scan_nodes
);
1682 * We call this when we hit limit, not when pages are added to LRU.
1683 * No LRU may hold pages because all pages are UNEVICTABLE or
1684 * memcg is too small and all pages are not on LRU. In that case,
1685 * we use curret node.
1687 if (unlikely(node
== MAX_NUMNODES
))
1688 node
= numa_node_id();
1690 memcg
->last_scanned_node
= node
;
1695 * Check all nodes whether it contains reclaimable pages or not.
1696 * For quick scan, we make use of scan_nodes. This will allow us to skip
1697 * unused nodes. But scan_nodes is lazily updated and may not cotain
1698 * enough new information. We need to do double check.
1700 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1705 * quick check...making use of scan_node.
1706 * We can skip unused nodes.
1708 if (!nodes_empty(memcg
->scan_nodes
)) {
1709 for (nid
= first_node(memcg
->scan_nodes
);
1711 nid
= next_node(nid
, memcg
->scan_nodes
)) {
1713 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1718 * Check rest of nodes.
1720 for_each_node_state(nid
, N_HIGH_MEMORY
) {
1721 if (node_isset(nid
, memcg
->scan_nodes
))
1723 if (test_mem_cgroup_node_reclaimable(memcg
, nid
, noswap
))
1730 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1735 static bool mem_cgroup_reclaimable(struct mem_cgroup
*memcg
, bool noswap
)
1737 return test_mem_cgroup_node_reclaimable(memcg
, 0, noswap
);
1741 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1744 unsigned long *total_scanned
)
1746 struct mem_cgroup
*victim
= NULL
;
1749 unsigned long excess
;
1750 unsigned long nr_scanned
;
1751 struct mem_cgroup_reclaim_cookie reclaim
= {
1756 excess
= res_counter_soft_limit_excess(&root_memcg
->res
) >> PAGE_SHIFT
;
1759 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1764 * If we have not been able to reclaim
1765 * anything, it might because there are
1766 * no reclaimable pages under this hierarchy
1771 * We want to do more targeted reclaim.
1772 * excess >> 2 is not to excessive so as to
1773 * reclaim too much, nor too less that we keep
1774 * coming back to reclaim from this cgroup
1776 if (total
>= (excess
>> 2) ||
1777 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1782 if (!mem_cgroup_reclaimable(victim
, false))
1784 total
+= mem_cgroup_shrink_node_zone(victim
, gfp_mask
, false,
1786 *total_scanned
+= nr_scanned
;
1787 if (!res_counter_soft_limit_excess(&root_memcg
->res
))
1790 mem_cgroup_iter_break(root_memcg
, victim
);
1795 * Check OOM-Killer is already running under our hierarchy.
1796 * If someone is running, return false.
1797 * Has to be called with memcg_oom_lock
1799 static bool mem_cgroup_oom_lock(struct mem_cgroup
*memcg
)
1801 struct mem_cgroup
*iter
, *failed
= NULL
;
1803 for_each_mem_cgroup_tree(iter
, memcg
) {
1804 if (iter
->oom_lock
) {
1806 * this subtree of our hierarchy is already locked
1807 * so we cannot give a lock.
1810 mem_cgroup_iter_break(memcg
, iter
);
1813 iter
->oom_lock
= true;
1820 * OK, we failed to lock the whole subtree so we have to clean up
1821 * what we set up to the failing subtree
1823 for_each_mem_cgroup_tree(iter
, memcg
) {
1824 if (iter
== failed
) {
1825 mem_cgroup_iter_break(memcg
, iter
);
1828 iter
->oom_lock
= false;
1834 * Has to be called with memcg_oom_lock
1836 static int mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1838 struct mem_cgroup
*iter
;
1840 for_each_mem_cgroup_tree(iter
, memcg
)
1841 iter
->oom_lock
= false;
1845 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1847 struct mem_cgroup
*iter
;
1849 for_each_mem_cgroup_tree(iter
, memcg
)
1850 atomic_inc(&iter
->under_oom
);
1853 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1855 struct mem_cgroup
*iter
;
1858 * When a new child is created while the hierarchy is under oom,
1859 * mem_cgroup_oom_lock() may not be called. We have to use
1860 * atomic_add_unless() here.
1862 for_each_mem_cgroup_tree(iter
, memcg
)
1863 atomic_add_unless(&iter
->under_oom
, -1, 0);
1866 static DEFINE_SPINLOCK(memcg_oom_lock
);
1867 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1869 struct oom_wait_info
{
1870 struct mem_cgroup
*memcg
;
1874 static int memcg_oom_wake_function(wait_queue_t
*wait
,
1875 unsigned mode
, int sync
, void *arg
)
1877 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1878 struct mem_cgroup
*oom_wait_memcg
;
1879 struct oom_wait_info
*oom_wait_info
;
1881 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1882 oom_wait_memcg
= oom_wait_info
->memcg
;
1885 * Both of oom_wait_info->memcg and wake_memcg are stable under us.
1886 * Then we can use css_is_ancestor without taking care of RCU.
1888 if (!mem_cgroup_same_or_subtree(oom_wait_memcg
, wake_memcg
)
1889 && !mem_cgroup_same_or_subtree(wake_memcg
, oom_wait_memcg
))
1891 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1894 static void memcg_wakeup_oom(struct mem_cgroup
*memcg
)
1896 /* for filtering, pass "memcg" as argument. */
1897 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1900 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1902 if (memcg
&& atomic_read(&memcg
->under_oom
))
1903 memcg_wakeup_oom(memcg
);
1907 * try to call OOM killer. returns false if we should exit memory-reclaim loop.
1909 static bool mem_cgroup_handle_oom(struct mem_cgroup
*memcg
, gfp_t mask
,
1912 struct oom_wait_info owait
;
1913 bool locked
, need_to_kill
;
1915 owait
.memcg
= memcg
;
1916 owait
.wait
.flags
= 0;
1917 owait
.wait
.func
= memcg_oom_wake_function
;
1918 owait
.wait
.private = current
;
1919 INIT_LIST_HEAD(&owait
.wait
.task_list
);
1920 need_to_kill
= true;
1921 mem_cgroup_mark_under_oom(memcg
);
1923 /* At first, try to OOM lock hierarchy under memcg.*/
1924 spin_lock(&memcg_oom_lock
);
1925 locked
= mem_cgroup_oom_lock(memcg
);
1927 * Even if signal_pending(), we can't quit charge() loop without
1928 * accounting. So, UNINTERRUPTIBLE is appropriate. But SIGKILL
1929 * under OOM is always welcomed, use TASK_KILLABLE here.
1931 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1932 if (!locked
|| memcg
->oom_kill_disable
)
1933 need_to_kill
= false;
1935 mem_cgroup_oom_notify(memcg
);
1936 spin_unlock(&memcg_oom_lock
);
1939 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1940 mem_cgroup_out_of_memory(memcg
, mask
, order
);
1943 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1945 spin_lock(&memcg_oom_lock
);
1947 mem_cgroup_oom_unlock(memcg
);
1948 memcg_wakeup_oom(memcg
);
1949 spin_unlock(&memcg_oom_lock
);
1951 mem_cgroup_unmark_under_oom(memcg
);
1953 if (test_thread_flag(TIF_MEMDIE
) || fatal_signal_pending(current
))
1955 /* Give chance to dying process */
1956 schedule_timeout_uninterruptible(1);
1961 * Currently used to update mapped file statistics, but the routine can be
1962 * generalized to update other statistics as well.
1964 * Notes: Race condition
1966 * We usually use page_cgroup_lock() for accessing page_cgroup member but
1967 * it tends to be costly. But considering some conditions, we doesn't need
1968 * to do so _always_.
1970 * Considering "charge", lock_page_cgroup() is not required because all
1971 * file-stat operations happen after a page is attached to radix-tree. There
1972 * are no race with "charge".
1974 * Considering "uncharge", we know that memcg doesn't clear pc->mem_cgroup
1975 * at "uncharge" intentionally. So, we always see valid pc->mem_cgroup even
1976 * if there are race with "uncharge". Statistics itself is properly handled
1979 * Considering "move", this is an only case we see a race. To make the race
1980 * small, we check mm->moving_account and detect there are possibility of race
1981 * If there is, we take a lock.
1984 void __mem_cgroup_begin_update_page_stat(struct page
*page
,
1985 bool *locked
, unsigned long *flags
)
1987 struct mem_cgroup
*memcg
;
1988 struct page_cgroup
*pc
;
1990 pc
= lookup_page_cgroup(page
);
1992 memcg
= pc
->mem_cgroup
;
1993 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
1996 * If this memory cgroup is not under account moving, we don't
1997 * need to take move_lock_mem_cgroup(). Because we already hold
1998 * rcu_read_lock(), any calls to move_account will be delayed until
1999 * rcu_read_unlock() if mem_cgroup_stolen() == true.
2001 if (!mem_cgroup_stolen(memcg
))
2004 move_lock_mem_cgroup(memcg
, flags
);
2005 if (memcg
!= pc
->mem_cgroup
|| !PageCgroupUsed(pc
)) {
2006 move_unlock_mem_cgroup(memcg
, flags
);
2012 void __mem_cgroup_end_update_page_stat(struct page
*page
, unsigned long *flags
)
2014 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2017 * It's guaranteed that pc->mem_cgroup never changes while
2018 * lock is held because a routine modifies pc->mem_cgroup
2019 * should take move_lock_mem_cgroup().
2021 move_unlock_mem_cgroup(pc
->mem_cgroup
, flags
);
2024 void mem_cgroup_update_page_stat(struct page
*page
,
2025 enum mem_cgroup_page_stat_item idx
, int val
)
2027 struct mem_cgroup
*memcg
;
2028 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2029 unsigned long uninitialized_var(flags
);
2031 if (mem_cgroup_disabled())
2034 memcg
= pc
->mem_cgroup
;
2035 if (unlikely(!memcg
|| !PageCgroupUsed(pc
)))
2039 case MEMCG_NR_FILE_MAPPED
:
2040 idx
= MEM_CGROUP_STAT_FILE_MAPPED
;
2046 this_cpu_add(memcg
->stat
->count
[idx
], val
);
2050 * size of first charge trial. "32" comes from vmscan.c's magic value.
2051 * TODO: maybe necessary to use big numbers in big irons.
2053 #define CHARGE_BATCH 32U
2054 struct memcg_stock_pcp
{
2055 struct mem_cgroup
*cached
; /* this never be root cgroup */
2056 unsigned int nr_pages
;
2057 struct work_struct work
;
2058 unsigned long flags
;
2059 #define FLUSHING_CACHED_CHARGE 0
2061 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2062 static DEFINE_MUTEX(percpu_charge_mutex
);
2065 * Try to consume stocked charge on this cpu. If success, one page is consumed
2066 * from local stock and true is returned. If the stock is 0 or charges from a
2067 * cgroup which is not current target, returns false. This stock will be
2070 static bool consume_stock(struct mem_cgroup
*memcg
)
2072 struct memcg_stock_pcp
*stock
;
2075 stock
= &get_cpu_var(memcg_stock
);
2076 if (memcg
== stock
->cached
&& stock
->nr_pages
)
2078 else /* need to call res_counter_charge */
2080 put_cpu_var(memcg_stock
);
2085 * Returns stocks cached in percpu to res_counter and reset cached information.
2087 static void drain_stock(struct memcg_stock_pcp
*stock
)
2089 struct mem_cgroup
*old
= stock
->cached
;
2091 if (stock
->nr_pages
) {
2092 unsigned long bytes
= stock
->nr_pages
* PAGE_SIZE
;
2094 res_counter_uncharge(&old
->res
, bytes
);
2095 if (do_swap_account
)
2096 res_counter_uncharge(&old
->memsw
, bytes
);
2097 stock
->nr_pages
= 0;
2099 stock
->cached
= NULL
;
2103 * This must be called under preempt disabled or must be called by
2104 * a thread which is pinned to local cpu.
2106 static void drain_local_stock(struct work_struct
*dummy
)
2108 struct memcg_stock_pcp
*stock
= &__get_cpu_var(memcg_stock
);
2110 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2114 * Cache charges(val) which is from res_counter, to local per_cpu area.
2115 * This will be consumed by consume_stock() function, later.
2117 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2119 struct memcg_stock_pcp
*stock
= &get_cpu_var(memcg_stock
);
2121 if (stock
->cached
!= memcg
) { /* reset if necessary */
2123 stock
->cached
= memcg
;
2125 stock
->nr_pages
+= nr_pages
;
2126 put_cpu_var(memcg_stock
);
2130 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2131 * of the hierarchy under it. sync flag says whether we should block
2132 * until the work is done.
2134 static void drain_all_stock(struct mem_cgroup
*root_memcg
, bool sync
)
2138 /* Notify other cpus that system-wide "drain" is running */
2141 for_each_online_cpu(cpu
) {
2142 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2143 struct mem_cgroup
*memcg
;
2145 memcg
= stock
->cached
;
2146 if (!memcg
|| !stock
->nr_pages
)
2148 if (!mem_cgroup_same_or_subtree(root_memcg
, memcg
))
2150 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2152 drain_local_stock(&stock
->work
);
2154 schedule_work_on(cpu
, &stock
->work
);
2162 for_each_online_cpu(cpu
) {
2163 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2164 if (test_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
))
2165 flush_work(&stock
->work
);
2172 * Tries to drain stocked charges in other cpus. This function is asynchronous
2173 * and just put a work per cpu for draining localy on each cpu. Caller can
2174 * expects some charges will be back to res_counter later but cannot wait for
2177 static void drain_all_stock_async(struct mem_cgroup
*root_memcg
)
2180 * If someone calls draining, avoid adding more kworker runs.
2182 if (!mutex_trylock(&percpu_charge_mutex
))
2184 drain_all_stock(root_memcg
, false);
2185 mutex_unlock(&percpu_charge_mutex
);
2188 /* This is a synchronous drain interface. */
2189 static void drain_all_stock_sync(struct mem_cgroup
*root_memcg
)
2191 /* called when force_empty is called */
2192 mutex_lock(&percpu_charge_mutex
);
2193 drain_all_stock(root_memcg
, true);
2194 mutex_unlock(&percpu_charge_mutex
);
2198 * This function drains percpu counter value from DEAD cpu and
2199 * move it to local cpu. Note that this function can be preempted.
2201 static void mem_cgroup_drain_pcp_counter(struct mem_cgroup
*memcg
, int cpu
)
2205 spin_lock(&memcg
->pcp_counter_lock
);
2206 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
2207 long x
= per_cpu(memcg
->stat
->count
[i
], cpu
);
2209 per_cpu(memcg
->stat
->count
[i
], cpu
) = 0;
2210 memcg
->nocpu_base
.count
[i
] += x
;
2212 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
2213 unsigned long x
= per_cpu(memcg
->stat
->events
[i
], cpu
);
2215 per_cpu(memcg
->stat
->events
[i
], cpu
) = 0;
2216 memcg
->nocpu_base
.events
[i
] += x
;
2218 spin_unlock(&memcg
->pcp_counter_lock
);
2221 static int __cpuinit
memcg_cpu_hotplug_callback(struct notifier_block
*nb
,
2222 unsigned long action
,
2225 int cpu
= (unsigned long)hcpu
;
2226 struct memcg_stock_pcp
*stock
;
2227 struct mem_cgroup
*iter
;
2229 if (action
== CPU_ONLINE
)
2232 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
2235 for_each_mem_cgroup(iter
)
2236 mem_cgroup_drain_pcp_counter(iter
, cpu
);
2238 stock
= &per_cpu(memcg_stock
, cpu
);
2244 /* See __mem_cgroup_try_charge() for details */
2246 CHARGE_OK
, /* success */
2247 CHARGE_RETRY
, /* need to retry but retry is not bad */
2248 CHARGE_NOMEM
, /* we can't do more. return -ENOMEM */
2249 CHARGE_WOULDBLOCK
, /* GFP_WAIT wasn't set and no enough res. */
2250 CHARGE_OOM_DIE
, /* the current is killed because of OOM */
2253 static int mem_cgroup_do_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2254 unsigned int nr_pages
, bool oom_check
)
2256 unsigned long csize
= nr_pages
* PAGE_SIZE
;
2257 struct mem_cgroup
*mem_over_limit
;
2258 struct res_counter
*fail_res
;
2259 unsigned long flags
= 0;
2262 ret
= res_counter_charge(&memcg
->res
, csize
, &fail_res
);
2265 if (!do_swap_account
)
2267 ret
= res_counter_charge(&memcg
->memsw
, csize
, &fail_res
);
2271 res_counter_uncharge(&memcg
->res
, csize
);
2272 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, memsw
);
2273 flags
|= MEM_CGROUP_RECLAIM_NOSWAP
;
2275 mem_over_limit
= mem_cgroup_from_res_counter(fail_res
, res
);
2277 * nr_pages can be either a huge page (HPAGE_PMD_NR), a batch
2278 * of regular pages (CHARGE_BATCH), or a single regular page (1).
2280 * Never reclaim on behalf of optional batching, retry with a
2281 * single page instead.
2283 if (nr_pages
== CHARGE_BATCH
)
2284 return CHARGE_RETRY
;
2286 if (!(gfp_mask
& __GFP_WAIT
))
2287 return CHARGE_WOULDBLOCK
;
2289 ret
= mem_cgroup_reclaim(mem_over_limit
, gfp_mask
, flags
);
2290 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2291 return CHARGE_RETRY
;
2293 * Even though the limit is exceeded at this point, reclaim
2294 * may have been able to free some pages. Retry the charge
2295 * before killing the task.
2297 * Only for regular pages, though: huge pages are rather
2298 * unlikely to succeed so close to the limit, and we fall back
2299 * to regular pages anyway in case of failure.
2301 if (nr_pages
== 1 && ret
)
2302 return CHARGE_RETRY
;
2305 * At task move, charge accounts can be doubly counted. So, it's
2306 * better to wait until the end of task_move if something is going on.
2308 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2309 return CHARGE_RETRY
;
2311 /* If we don't need to call oom-killer at el, return immediately */
2313 return CHARGE_NOMEM
;
2315 if (!mem_cgroup_handle_oom(mem_over_limit
, gfp_mask
, get_order(csize
)))
2316 return CHARGE_OOM_DIE
;
2318 return CHARGE_RETRY
;
2322 * __mem_cgroup_try_charge() does
2323 * 1. detect memcg to be charged against from passed *mm and *ptr,
2324 * 2. update res_counter
2325 * 3. call memory reclaim if necessary.
2327 * In some special case, if the task is fatal, fatal_signal_pending() or
2328 * has TIF_MEMDIE, this function returns -EINTR while writing root_mem_cgroup
2329 * to *ptr. There are two reasons for this. 1: fatal threads should quit as soon
2330 * as possible without any hazards. 2: all pages should have a valid
2331 * pc->mem_cgroup. If mm is NULL and the caller doesn't pass a valid memcg
2332 * pointer, that is treated as a charge to root_mem_cgroup.
2334 * So __mem_cgroup_try_charge() will return
2335 * 0 ... on success, filling *ptr with a valid memcg pointer.
2336 * -ENOMEM ... charge failure because of resource limits.
2337 * -EINTR ... if thread is fatal. *ptr is filled with root_mem_cgroup.
2339 * Unlike the exported interface, an "oom" parameter is added. if oom==true,
2340 * the oom-killer can be invoked.
2342 static int __mem_cgroup_try_charge(struct mm_struct
*mm
,
2344 unsigned int nr_pages
,
2345 struct mem_cgroup
**ptr
,
2348 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
2349 int nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2350 struct mem_cgroup
*memcg
= NULL
;
2354 * Unlike gloval-vm's OOM-kill, we're not in memory shortage
2355 * in system level. So, allow to go ahead dying process in addition to
2358 if (unlikely(test_thread_flag(TIF_MEMDIE
)
2359 || fatal_signal_pending(current
)))
2363 * We always charge the cgroup the mm_struct belongs to.
2364 * The mm_struct's mem_cgroup changes on task migration if the
2365 * thread group leader migrates. It's possible that mm is not
2366 * set, if so charge the root memcg (happens for pagecache usage).
2369 *ptr
= root_mem_cgroup
;
2371 if (*ptr
) { /* css should be a valid one */
2373 if (mem_cgroup_is_root(memcg
))
2375 if (nr_pages
== 1 && consume_stock(memcg
))
2377 css_get(&memcg
->css
);
2379 struct task_struct
*p
;
2382 p
= rcu_dereference(mm
->owner
);
2384 * Because we don't have task_lock(), "p" can exit.
2385 * In that case, "memcg" can point to root or p can be NULL with
2386 * race with swapoff. Then, we have small risk of mis-accouning.
2387 * But such kind of mis-account by race always happens because
2388 * we don't have cgroup_mutex(). It's overkill and we allo that
2390 * (*) swapoff at el will charge against mm-struct not against
2391 * task-struct. So, mm->owner can be NULL.
2393 memcg
= mem_cgroup_from_task(p
);
2395 memcg
= root_mem_cgroup
;
2396 if (mem_cgroup_is_root(memcg
)) {
2400 if (nr_pages
== 1 && consume_stock(memcg
)) {
2402 * It seems dagerous to access memcg without css_get().
2403 * But considering how consume_stok works, it's not
2404 * necessary. If consume_stock success, some charges
2405 * from this memcg are cached on this cpu. So, we
2406 * don't need to call css_get()/css_tryget() before
2407 * calling consume_stock().
2412 /* after here, we may be blocked. we need to get refcnt */
2413 if (!css_tryget(&memcg
->css
)) {
2423 /* If killed, bypass charge */
2424 if (fatal_signal_pending(current
)) {
2425 css_put(&memcg
->css
);
2430 if (oom
&& !nr_oom_retries
) {
2432 nr_oom_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2435 ret
= mem_cgroup_do_charge(memcg
, gfp_mask
, batch
, oom_check
);
2439 case CHARGE_RETRY
: /* not in OOM situation but retry */
2441 css_put(&memcg
->css
);
2444 case CHARGE_WOULDBLOCK
: /* !__GFP_WAIT */
2445 css_put(&memcg
->css
);
2447 case CHARGE_NOMEM
: /* OOM routine works */
2449 css_put(&memcg
->css
);
2452 /* If oom, we never return -ENOMEM */
2455 case CHARGE_OOM_DIE
: /* Killed by OOM Killer */
2456 css_put(&memcg
->css
);
2459 } while (ret
!= CHARGE_OK
);
2461 if (batch
> nr_pages
)
2462 refill_stock(memcg
, batch
- nr_pages
);
2463 css_put(&memcg
->css
);
2471 *ptr
= root_mem_cgroup
;
2476 * Somemtimes we have to undo a charge we got by try_charge().
2477 * This function is for that and do uncharge, put css's refcnt.
2478 * gotten by try_charge().
2480 static void __mem_cgroup_cancel_charge(struct mem_cgroup
*memcg
,
2481 unsigned int nr_pages
)
2483 if (!mem_cgroup_is_root(memcg
)) {
2484 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2486 res_counter_uncharge(&memcg
->res
, bytes
);
2487 if (do_swap_account
)
2488 res_counter_uncharge(&memcg
->memsw
, bytes
);
2493 * Cancel chrages in this cgroup....doesn't propagate to parent cgroup.
2494 * This is useful when moving usage to parent cgroup.
2496 static void __mem_cgroup_cancel_local_charge(struct mem_cgroup
*memcg
,
2497 unsigned int nr_pages
)
2499 unsigned long bytes
= nr_pages
* PAGE_SIZE
;
2501 if (mem_cgroup_is_root(memcg
))
2504 res_counter_uncharge_until(&memcg
->res
, memcg
->res
.parent
, bytes
);
2505 if (do_swap_account
)
2506 res_counter_uncharge_until(&memcg
->memsw
,
2507 memcg
->memsw
.parent
, bytes
);
2511 * A helper function to get mem_cgroup from ID. must be called under
2512 * rcu_read_lock(). The caller is responsible for calling css_tryget if
2513 * the mem_cgroup is used for charging. (dropping refcnt from swap can be
2514 * called against removed memcg.)
2516 static struct mem_cgroup
*mem_cgroup_lookup(unsigned short id
)
2518 struct cgroup_subsys_state
*css
;
2520 /* ID 0 is unused ID */
2523 css
= css_lookup(&mem_cgroup_subsys
, id
);
2526 return mem_cgroup_from_css(css
);
2529 struct mem_cgroup
*try_get_mem_cgroup_from_page(struct page
*page
)
2531 struct mem_cgroup
*memcg
= NULL
;
2532 struct page_cgroup
*pc
;
2536 VM_BUG_ON(!PageLocked(page
));
2538 pc
= lookup_page_cgroup(page
);
2539 lock_page_cgroup(pc
);
2540 if (PageCgroupUsed(pc
)) {
2541 memcg
= pc
->mem_cgroup
;
2542 if (memcg
&& !css_tryget(&memcg
->css
))
2544 } else if (PageSwapCache(page
)) {
2545 ent
.val
= page_private(page
);
2546 id
= lookup_swap_cgroup_id(ent
);
2548 memcg
= mem_cgroup_lookup(id
);
2549 if (memcg
&& !css_tryget(&memcg
->css
))
2553 unlock_page_cgroup(pc
);
2557 static void __mem_cgroup_commit_charge(struct mem_cgroup
*memcg
,
2559 unsigned int nr_pages
,
2560 enum charge_type ctype
,
2563 struct page_cgroup
*pc
= lookup_page_cgroup(page
);
2564 struct zone
*uninitialized_var(zone
);
2565 struct lruvec
*lruvec
;
2566 bool was_on_lru
= false;
2569 lock_page_cgroup(pc
);
2570 VM_BUG_ON(PageCgroupUsed(pc
));
2572 * we don't need page_cgroup_lock about tail pages, becase they are not
2573 * accessed by any other context at this point.
2577 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2578 * may already be on some other mem_cgroup's LRU. Take care of it.
2581 zone
= page_zone(page
);
2582 spin_lock_irq(&zone
->lru_lock
);
2583 if (PageLRU(page
)) {
2584 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2586 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2591 pc
->mem_cgroup
= memcg
;
2593 * We access a page_cgroup asynchronously without lock_page_cgroup().
2594 * Especially when a page_cgroup is taken from a page, pc->mem_cgroup
2595 * is accessed after testing USED bit. To make pc->mem_cgroup visible
2596 * before USED bit, we need memory barrier here.
2597 * See mem_cgroup_add_lru_list(), etc.
2600 SetPageCgroupUsed(pc
);
2604 lruvec
= mem_cgroup_zone_lruvec(zone
, pc
->mem_cgroup
);
2605 VM_BUG_ON(PageLRU(page
));
2607 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2609 spin_unlock_irq(&zone
->lru_lock
);
2612 if (ctype
== MEM_CGROUP_CHARGE_TYPE_ANON
)
2617 mem_cgroup_charge_statistics(memcg
, anon
, nr_pages
);
2618 unlock_page_cgroup(pc
);
2621 * "charge_statistics" updated event counter. Then, check it.
2622 * Insert ancestor (and ancestor's ancestors), to softlimit RB-tree.
2623 * if they exceeds softlimit.
2625 memcg_check_events(memcg
, page
);
2628 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2630 #define PCGF_NOCOPY_AT_SPLIT (1 << PCG_LOCK | 1 << PCG_MIGRATION)
2632 * Because tail pages are not marked as "used", set it. We're under
2633 * zone->lru_lock, 'splitting on pmd' and compound_lock.
2634 * charge/uncharge will be never happen and move_account() is done under
2635 * compound_lock(), so we don't have to take care of races.
2637 void mem_cgroup_split_huge_fixup(struct page
*head
)
2639 struct page_cgroup
*head_pc
= lookup_page_cgroup(head
);
2640 struct page_cgroup
*pc
;
2643 if (mem_cgroup_disabled())
2645 for (i
= 1; i
< HPAGE_PMD_NR
; i
++) {
2647 pc
->mem_cgroup
= head_pc
->mem_cgroup
;
2648 smp_wmb();/* see __commit_charge() */
2649 pc
->flags
= head_pc
->flags
& ~PCGF_NOCOPY_AT_SPLIT
;
2652 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2655 * mem_cgroup_move_account - move account of the page
2657 * @nr_pages: number of regular pages (>1 for huge pages)
2658 * @pc: page_cgroup of the page.
2659 * @from: mem_cgroup which the page is moved from.
2660 * @to: mem_cgroup which the page is moved to. @from != @to.
2662 * The caller must confirm following.
2663 * - page is not on LRU (isolate_page() is useful.)
2664 * - compound_lock is held when nr_pages > 1
2666 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
2669 static int mem_cgroup_move_account(struct page
*page
,
2670 unsigned int nr_pages
,
2671 struct page_cgroup
*pc
,
2672 struct mem_cgroup
*from
,
2673 struct mem_cgroup
*to
)
2675 unsigned long flags
;
2677 bool anon
= PageAnon(page
);
2679 VM_BUG_ON(from
== to
);
2680 VM_BUG_ON(PageLRU(page
));
2682 * The page is isolated from LRU. So, collapse function
2683 * will not handle this page. But page splitting can happen.
2684 * Do this check under compound_page_lock(). The caller should
2688 if (nr_pages
> 1 && !PageTransHuge(page
))
2691 lock_page_cgroup(pc
);
2694 if (!PageCgroupUsed(pc
) || pc
->mem_cgroup
!= from
)
2697 move_lock_mem_cgroup(from
, &flags
);
2699 if (!anon
&& page_mapped(page
)) {
2700 /* Update mapped_file data for mem_cgroup */
2702 __this_cpu_dec(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
2703 __this_cpu_inc(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
]);
2706 mem_cgroup_charge_statistics(from
, anon
, -nr_pages
);
2708 /* caller should have done css_get */
2709 pc
->mem_cgroup
= to
;
2710 mem_cgroup_charge_statistics(to
, anon
, nr_pages
);
2711 move_unlock_mem_cgroup(from
, &flags
);
2714 unlock_page_cgroup(pc
);
2718 memcg_check_events(to
, page
);
2719 memcg_check_events(from
, page
);
2725 * mem_cgroup_move_parent - moves page to the parent group
2726 * @page: the page to move
2727 * @pc: page_cgroup of the page
2728 * @child: page's cgroup
2730 * move charges to its parent or the root cgroup if the group has no
2731 * parent (aka use_hierarchy==0).
2732 * Although this might fail (get_page_unless_zero, isolate_lru_page or
2733 * mem_cgroup_move_account fails) the failure is always temporary and
2734 * it signals a race with a page removal/uncharge or migration. In the
2735 * first case the page is on the way out and it will vanish from the LRU
2736 * on the next attempt and the call should be retried later.
2737 * Isolation from the LRU fails only if page has been isolated from
2738 * the LRU since we looked at it and that usually means either global
2739 * reclaim or migration going on. The page will either get back to the
2741 * Finaly mem_cgroup_move_account fails only if the page got uncharged
2742 * (!PageCgroupUsed) or moved to a different group. The page will
2743 * disappear in the next attempt.
2745 static int mem_cgroup_move_parent(struct page
*page
,
2746 struct page_cgroup
*pc
,
2747 struct mem_cgroup
*child
)
2749 struct mem_cgroup
*parent
;
2750 unsigned int nr_pages
;
2751 unsigned long uninitialized_var(flags
);
2754 VM_BUG_ON(mem_cgroup_is_root(child
));
2757 if (!get_page_unless_zero(page
))
2759 if (isolate_lru_page(page
))
2762 nr_pages
= hpage_nr_pages(page
);
2764 parent
= parent_mem_cgroup(child
);
2766 * If no parent, move charges to root cgroup.
2769 parent
= root_mem_cgroup
;
2772 VM_BUG_ON(!PageTransHuge(page
));
2773 flags
= compound_lock_irqsave(page
);
2776 ret
= mem_cgroup_move_account(page
, nr_pages
,
2779 __mem_cgroup_cancel_local_charge(child
, nr_pages
);
2782 compound_unlock_irqrestore(page
, flags
);
2783 putback_lru_page(page
);
2791 * Charge the memory controller for page usage.
2793 * 0 if the charge was successful
2794 * < 0 if the cgroup is over its limit
2796 static int mem_cgroup_charge_common(struct page
*page
, struct mm_struct
*mm
,
2797 gfp_t gfp_mask
, enum charge_type ctype
)
2799 struct mem_cgroup
*memcg
= NULL
;
2800 unsigned int nr_pages
= 1;
2804 if (PageTransHuge(page
)) {
2805 nr_pages
<<= compound_order(page
);
2806 VM_BUG_ON(!PageTransHuge(page
));
2808 * Never OOM-kill a process for a huge page. The
2809 * fault handler will fall back to regular pages.
2814 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, nr_pages
, &memcg
, oom
);
2817 __mem_cgroup_commit_charge(memcg
, page
, nr_pages
, ctype
, false);
2821 int mem_cgroup_newpage_charge(struct page
*page
,
2822 struct mm_struct
*mm
, gfp_t gfp_mask
)
2824 if (mem_cgroup_disabled())
2826 VM_BUG_ON(page_mapped(page
));
2827 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
2829 return mem_cgroup_charge_common(page
, mm
, gfp_mask
,
2830 MEM_CGROUP_CHARGE_TYPE_ANON
);
2834 * While swap-in, try_charge -> commit or cancel, the page is locked.
2835 * And when try_charge() successfully returns, one refcnt to memcg without
2836 * struct page_cgroup is acquired. This refcnt will be consumed by
2837 * "commit()" or removed by "cancel()"
2839 static int __mem_cgroup_try_charge_swapin(struct mm_struct
*mm
,
2842 struct mem_cgroup
**memcgp
)
2844 struct mem_cgroup
*memcg
;
2845 struct page_cgroup
*pc
;
2848 pc
= lookup_page_cgroup(page
);
2850 * Every swap fault against a single page tries to charge the
2851 * page, bail as early as possible. shmem_unuse() encounters
2852 * already charged pages, too. The USED bit is protected by
2853 * the page lock, which serializes swap cache removal, which
2854 * in turn serializes uncharging.
2856 if (PageCgroupUsed(pc
))
2858 if (!do_swap_account
)
2860 memcg
= try_get_mem_cgroup_from_page(page
);
2864 ret
= __mem_cgroup_try_charge(NULL
, mask
, 1, memcgp
, true);
2865 css_put(&memcg
->css
);
2870 ret
= __mem_cgroup_try_charge(mm
, mask
, 1, memcgp
, true);
2876 int mem_cgroup_try_charge_swapin(struct mm_struct
*mm
, struct page
*page
,
2877 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
)
2880 if (mem_cgroup_disabled())
2883 * A racing thread's fault, or swapoff, may have already
2884 * updated the pte, and even removed page from swap cache: in
2885 * those cases unuse_pte()'s pte_same() test will fail; but
2886 * there's also a KSM case which does need to charge the page.
2888 if (!PageSwapCache(page
)) {
2891 ret
= __mem_cgroup_try_charge(mm
, gfp_mask
, 1, memcgp
, true);
2896 return __mem_cgroup_try_charge_swapin(mm
, page
, gfp_mask
, memcgp
);
2899 void mem_cgroup_cancel_charge_swapin(struct mem_cgroup
*memcg
)
2901 if (mem_cgroup_disabled())
2905 __mem_cgroup_cancel_charge(memcg
, 1);
2909 __mem_cgroup_commit_charge_swapin(struct page
*page
, struct mem_cgroup
*memcg
,
2910 enum charge_type ctype
)
2912 if (mem_cgroup_disabled())
2917 __mem_cgroup_commit_charge(memcg
, page
, 1, ctype
, true);
2919 * Now swap is on-memory. This means this page may be
2920 * counted both as mem and swap....double count.
2921 * Fix it by uncharging from memsw. Basically, this SwapCache is stable
2922 * under lock_page(). But in do_swap_page()::memory.c, reuse_swap_page()
2923 * may call delete_from_swap_cache() before reach here.
2925 if (do_swap_account
&& PageSwapCache(page
)) {
2926 swp_entry_t ent
= {.val
= page_private(page
)};
2927 mem_cgroup_uncharge_swap(ent
);
2931 void mem_cgroup_commit_charge_swapin(struct page
*page
,
2932 struct mem_cgroup
*memcg
)
2934 __mem_cgroup_commit_charge_swapin(page
, memcg
,
2935 MEM_CGROUP_CHARGE_TYPE_ANON
);
2938 int mem_cgroup_cache_charge(struct page
*page
, struct mm_struct
*mm
,
2941 struct mem_cgroup
*memcg
= NULL
;
2942 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
2945 if (mem_cgroup_disabled())
2947 if (PageCompound(page
))
2950 if (!PageSwapCache(page
))
2951 ret
= mem_cgroup_charge_common(page
, mm
, gfp_mask
, type
);
2952 else { /* page is swapcache/shmem */
2953 ret
= __mem_cgroup_try_charge_swapin(mm
, page
,
2956 __mem_cgroup_commit_charge_swapin(page
, memcg
, type
);
2961 static void mem_cgroup_do_uncharge(struct mem_cgroup
*memcg
,
2962 unsigned int nr_pages
,
2963 const enum charge_type ctype
)
2965 struct memcg_batch_info
*batch
= NULL
;
2966 bool uncharge_memsw
= true;
2968 /* If swapout, usage of swap doesn't decrease */
2969 if (!do_swap_account
|| ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
)
2970 uncharge_memsw
= false;
2972 batch
= ¤t
->memcg_batch
;
2974 * In usual, we do css_get() when we remember memcg pointer.
2975 * But in this case, we keep res->usage until end of a series of
2976 * uncharges. Then, it's ok to ignore memcg's refcnt.
2979 batch
->memcg
= memcg
;
2981 * do_batch > 0 when unmapping pages or inode invalidate/truncate.
2982 * In those cases, all pages freed continuously can be expected to be in
2983 * the same cgroup and we have chance to coalesce uncharges.
2984 * But we do uncharge one by one if this is killed by OOM(TIF_MEMDIE)
2985 * because we want to do uncharge as soon as possible.
2988 if (!batch
->do_batch
|| test_thread_flag(TIF_MEMDIE
))
2989 goto direct_uncharge
;
2992 goto direct_uncharge
;
2995 * In typical case, batch->memcg == mem. This means we can
2996 * merge a series of uncharges to an uncharge of res_counter.
2997 * If not, we uncharge res_counter ony by one.
2999 if (batch
->memcg
!= memcg
)
3000 goto direct_uncharge
;
3001 /* remember freed charge and uncharge it later */
3004 batch
->memsw_nr_pages
++;
3007 res_counter_uncharge(&memcg
->res
, nr_pages
* PAGE_SIZE
);
3009 res_counter_uncharge(&memcg
->memsw
, nr_pages
* PAGE_SIZE
);
3010 if (unlikely(batch
->memcg
!= memcg
))
3011 memcg_oom_recover(memcg
);
3015 * uncharge if !page_mapped(page)
3017 static struct mem_cgroup
*
3018 __mem_cgroup_uncharge_common(struct page
*page
, enum charge_type ctype
,
3021 struct mem_cgroup
*memcg
= NULL
;
3022 unsigned int nr_pages
= 1;
3023 struct page_cgroup
*pc
;
3026 if (mem_cgroup_disabled())
3029 VM_BUG_ON(PageSwapCache(page
));
3031 if (PageTransHuge(page
)) {
3032 nr_pages
<<= compound_order(page
);
3033 VM_BUG_ON(!PageTransHuge(page
));
3036 * Check if our page_cgroup is valid
3038 pc
= lookup_page_cgroup(page
);
3039 if (unlikely(!PageCgroupUsed(pc
)))
3042 lock_page_cgroup(pc
);
3044 memcg
= pc
->mem_cgroup
;
3046 if (!PageCgroupUsed(pc
))
3049 anon
= PageAnon(page
);
3052 case MEM_CGROUP_CHARGE_TYPE_ANON
:
3054 * Generally PageAnon tells if it's the anon statistics to be
3055 * updated; but sometimes e.g. mem_cgroup_uncharge_page() is
3056 * used before page reached the stage of being marked PageAnon.
3060 case MEM_CGROUP_CHARGE_TYPE_DROP
:
3061 /* See mem_cgroup_prepare_migration() */
3062 if (page_mapped(page
))
3065 * Pages under migration may not be uncharged. But
3066 * end_migration() /must/ be the one uncharging the
3067 * unused post-migration page and so it has to call
3068 * here with the migration bit still set. See the
3069 * res_counter handling below.
3071 if (!end_migration
&& PageCgroupMigration(pc
))
3074 case MEM_CGROUP_CHARGE_TYPE_SWAPOUT
:
3075 if (!PageAnon(page
)) { /* Shared memory */
3076 if (page
->mapping
&& !page_is_file_cache(page
))
3078 } else if (page_mapped(page
)) /* Anon */
3085 mem_cgroup_charge_statistics(memcg
, anon
, -nr_pages
);
3087 ClearPageCgroupUsed(pc
);
3089 * pc->mem_cgroup is not cleared here. It will be accessed when it's
3090 * freed from LRU. This is safe because uncharged page is expected not
3091 * to be reused (freed soon). Exception is SwapCache, it's handled by
3092 * special functions.
3095 unlock_page_cgroup(pc
);
3097 * even after unlock, we have memcg->res.usage here and this memcg
3098 * will never be freed.
3100 memcg_check_events(memcg
, page
);
3101 if (do_swap_account
&& ctype
== MEM_CGROUP_CHARGE_TYPE_SWAPOUT
) {
3102 mem_cgroup_swap_statistics(memcg
, true);
3103 mem_cgroup_get(memcg
);
3106 * Migration does not charge the res_counter for the
3107 * replacement page, so leave it alone when phasing out the
3108 * page that is unused after the migration.
3110 if (!end_migration
&& !mem_cgroup_is_root(memcg
))
3111 mem_cgroup_do_uncharge(memcg
, nr_pages
, ctype
);
3116 unlock_page_cgroup(pc
);
3120 void mem_cgroup_uncharge_page(struct page
*page
)
3123 if (page_mapped(page
))
3125 VM_BUG_ON(page
->mapping
&& !PageAnon(page
));
3126 if (PageSwapCache(page
))
3128 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_ANON
, false);
3131 void mem_cgroup_uncharge_cache_page(struct page
*page
)
3133 VM_BUG_ON(page_mapped(page
));
3134 VM_BUG_ON(page
->mapping
);
3135 __mem_cgroup_uncharge_common(page
, MEM_CGROUP_CHARGE_TYPE_CACHE
, false);
3139 * Batch_start/batch_end is called in unmap_page_range/invlidate/trucate.
3140 * In that cases, pages are freed continuously and we can expect pages
3141 * are in the same memcg. All these calls itself limits the number of
3142 * pages freed at once, then uncharge_start/end() is called properly.
3143 * This may be called prural(2) times in a context,
3146 void mem_cgroup_uncharge_start(void)
3148 current
->memcg_batch
.do_batch
++;
3149 /* We can do nest. */
3150 if (current
->memcg_batch
.do_batch
== 1) {
3151 current
->memcg_batch
.memcg
= NULL
;
3152 current
->memcg_batch
.nr_pages
= 0;
3153 current
->memcg_batch
.memsw_nr_pages
= 0;
3157 void mem_cgroup_uncharge_end(void)
3159 struct memcg_batch_info
*batch
= ¤t
->memcg_batch
;
3161 if (!batch
->do_batch
)
3165 if (batch
->do_batch
) /* If stacked, do nothing. */
3171 * This "batch->memcg" is valid without any css_get/put etc...
3172 * bacause we hide charges behind us.
3174 if (batch
->nr_pages
)
3175 res_counter_uncharge(&batch
->memcg
->res
,
3176 batch
->nr_pages
* PAGE_SIZE
);
3177 if (batch
->memsw_nr_pages
)
3178 res_counter_uncharge(&batch
->memcg
->memsw
,
3179 batch
->memsw_nr_pages
* PAGE_SIZE
);
3180 memcg_oom_recover(batch
->memcg
);
3181 /* forget this pointer (for sanity check) */
3182 batch
->memcg
= NULL
;
3187 * called after __delete_from_swap_cache() and drop "page" account.
3188 * memcg information is recorded to swap_cgroup of "ent"
3191 mem_cgroup_uncharge_swapcache(struct page
*page
, swp_entry_t ent
, bool swapout
)
3193 struct mem_cgroup
*memcg
;
3194 int ctype
= MEM_CGROUP_CHARGE_TYPE_SWAPOUT
;
3196 if (!swapout
) /* this was a swap cache but the swap is unused ! */
3197 ctype
= MEM_CGROUP_CHARGE_TYPE_DROP
;
3199 memcg
= __mem_cgroup_uncharge_common(page
, ctype
, false);
3202 * record memcg information, if swapout && memcg != NULL,
3203 * mem_cgroup_get() was called in uncharge().
3205 if (do_swap_account
&& swapout
&& memcg
)
3206 swap_cgroup_record(ent
, css_id(&memcg
->css
));
3210 #ifdef CONFIG_MEMCG_SWAP
3212 * called from swap_entry_free(). remove record in swap_cgroup and
3213 * uncharge "memsw" account.
3215 void mem_cgroup_uncharge_swap(swp_entry_t ent
)
3217 struct mem_cgroup
*memcg
;
3220 if (!do_swap_account
)
3223 id
= swap_cgroup_record(ent
, 0);
3225 memcg
= mem_cgroup_lookup(id
);
3228 * We uncharge this because swap is freed.
3229 * This memcg can be obsolete one. We avoid calling css_tryget
3231 if (!mem_cgroup_is_root(memcg
))
3232 res_counter_uncharge(&memcg
->memsw
, PAGE_SIZE
);
3233 mem_cgroup_swap_statistics(memcg
, false);
3234 mem_cgroup_put(memcg
);
3240 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3241 * @entry: swap entry to be moved
3242 * @from: mem_cgroup which the entry is moved from
3243 * @to: mem_cgroup which the entry is moved to
3245 * It succeeds only when the swap_cgroup's record for this entry is the same
3246 * as the mem_cgroup's id of @from.
3248 * Returns 0 on success, -EINVAL on failure.
3250 * The caller must have charged to @to, IOW, called res_counter_charge() about
3251 * both res and memsw, and called css_get().
3253 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3254 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3256 unsigned short old_id
, new_id
;
3258 old_id
= css_id(&from
->css
);
3259 new_id
= css_id(&to
->css
);
3261 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3262 mem_cgroup_swap_statistics(from
, false);
3263 mem_cgroup_swap_statistics(to
, true);
3265 * This function is only called from task migration context now.
3266 * It postpones res_counter and refcount handling till the end
3267 * of task migration(mem_cgroup_clear_mc()) for performance
3268 * improvement. But we cannot postpone mem_cgroup_get(to)
3269 * because if the process that has been moved to @to does
3270 * swap-in, the refcount of @to might be decreased to 0.
3278 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3279 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3286 * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
3289 void mem_cgroup_prepare_migration(struct page
*page
, struct page
*newpage
,
3290 struct mem_cgroup
**memcgp
)
3292 struct mem_cgroup
*memcg
= NULL
;
3293 struct page_cgroup
*pc
;
3294 enum charge_type ctype
;
3298 VM_BUG_ON(PageTransHuge(page
));
3299 if (mem_cgroup_disabled())
3302 pc
= lookup_page_cgroup(page
);
3303 lock_page_cgroup(pc
);
3304 if (PageCgroupUsed(pc
)) {
3305 memcg
= pc
->mem_cgroup
;
3306 css_get(&memcg
->css
);
3308 * At migrating an anonymous page, its mapcount goes down
3309 * to 0 and uncharge() will be called. But, even if it's fully
3310 * unmapped, migration may fail and this page has to be
3311 * charged again. We set MIGRATION flag here and delay uncharge
3312 * until end_migration() is called
3314 * Corner Case Thinking
3316 * When the old page was mapped as Anon and it's unmap-and-freed
3317 * while migration was ongoing.
3318 * If unmap finds the old page, uncharge() of it will be delayed
3319 * until end_migration(). If unmap finds a new page, it's
3320 * uncharged when it make mapcount to be 1->0. If unmap code
3321 * finds swap_migration_entry, the new page will not be mapped
3322 * and end_migration() will find it(mapcount==0).
3325 * When the old page was mapped but migraion fails, the kernel
3326 * remaps it. A charge for it is kept by MIGRATION flag even
3327 * if mapcount goes down to 0. We can do remap successfully
3328 * without charging it again.
3331 * The "old" page is under lock_page() until the end of
3332 * migration, so, the old page itself will not be swapped-out.
3333 * If the new page is swapped out before end_migraton, our
3334 * hook to usual swap-out path will catch the event.
3337 SetPageCgroupMigration(pc
);
3339 unlock_page_cgroup(pc
);
3341 * If the page is not charged at this point,
3349 * We charge new page before it's used/mapped. So, even if unlock_page()
3350 * is called before end_migration, we can catch all events on this new
3351 * page. In the case new page is migrated but not remapped, new page's
3352 * mapcount will be finally 0 and we call uncharge in end_migration().
3355 ctype
= MEM_CGROUP_CHARGE_TYPE_ANON
;
3357 ctype
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
3359 * The page is committed to the memcg, but it's not actually
3360 * charged to the res_counter since we plan on replacing the
3361 * old one and only one page is going to be left afterwards.
3363 __mem_cgroup_commit_charge(memcg
, newpage
, 1, ctype
, false);
3366 /* remove redundant charge if migration failed*/
3367 void mem_cgroup_end_migration(struct mem_cgroup
*memcg
,
3368 struct page
*oldpage
, struct page
*newpage
, bool migration_ok
)
3370 struct page
*used
, *unused
;
3371 struct page_cgroup
*pc
;
3377 if (!migration_ok
) {
3384 anon
= PageAnon(used
);
3385 __mem_cgroup_uncharge_common(unused
,
3386 anon
? MEM_CGROUP_CHARGE_TYPE_ANON
3387 : MEM_CGROUP_CHARGE_TYPE_CACHE
,
3389 css_put(&memcg
->css
);
3391 * We disallowed uncharge of pages under migration because mapcount
3392 * of the page goes down to zero, temporarly.
3393 * Clear the flag and check the page should be charged.
3395 pc
= lookup_page_cgroup(oldpage
);
3396 lock_page_cgroup(pc
);
3397 ClearPageCgroupMigration(pc
);
3398 unlock_page_cgroup(pc
);
3401 * If a page is a file cache, radix-tree replacement is very atomic
3402 * and we can skip this check. When it was an Anon page, its mapcount
3403 * goes down to 0. But because we added MIGRATION flage, it's not
3404 * uncharged yet. There are several case but page->mapcount check
3405 * and USED bit check in mem_cgroup_uncharge_page() will do enough
3406 * check. (see prepare_charge() also)
3409 mem_cgroup_uncharge_page(used
);
3413 * At replace page cache, newpage is not under any memcg but it's on
3414 * LRU. So, this function doesn't touch res_counter but handles LRU
3415 * in correct way. Both pages are locked so we cannot race with uncharge.
3417 void mem_cgroup_replace_page_cache(struct page
*oldpage
,
3418 struct page
*newpage
)
3420 struct mem_cgroup
*memcg
= NULL
;
3421 struct page_cgroup
*pc
;
3422 enum charge_type type
= MEM_CGROUP_CHARGE_TYPE_CACHE
;
3424 if (mem_cgroup_disabled())
3427 pc
= lookup_page_cgroup(oldpage
);
3428 /* fix accounting on old pages */
3429 lock_page_cgroup(pc
);
3430 if (PageCgroupUsed(pc
)) {
3431 memcg
= pc
->mem_cgroup
;
3432 mem_cgroup_charge_statistics(memcg
, false, -1);
3433 ClearPageCgroupUsed(pc
);
3435 unlock_page_cgroup(pc
);
3438 * When called from shmem_replace_page(), in some cases the
3439 * oldpage has already been charged, and in some cases not.
3444 * Even if newpage->mapping was NULL before starting replacement,
3445 * the newpage may be on LRU(or pagevec for LRU) already. We lock
3446 * LRU while we overwrite pc->mem_cgroup.
3448 __mem_cgroup_commit_charge(memcg
, newpage
, 1, type
, true);
3451 #ifdef CONFIG_DEBUG_VM
3452 static struct page_cgroup
*lookup_page_cgroup_used(struct page
*page
)
3454 struct page_cgroup
*pc
;
3456 pc
= lookup_page_cgroup(page
);
3458 * Can be NULL while feeding pages into the page allocator for
3459 * the first time, i.e. during boot or memory hotplug;
3460 * or when mem_cgroup_disabled().
3462 if (likely(pc
) && PageCgroupUsed(pc
))
3467 bool mem_cgroup_bad_page_check(struct page
*page
)
3469 if (mem_cgroup_disabled())
3472 return lookup_page_cgroup_used(page
) != NULL
;
3475 void mem_cgroup_print_bad_page(struct page
*page
)
3477 struct page_cgroup
*pc
;
3479 pc
= lookup_page_cgroup_used(page
);
3481 printk(KERN_ALERT
"pc:%p pc->flags:%lx pc->mem_cgroup:%p\n",
3482 pc
, pc
->flags
, pc
->mem_cgroup
);
3487 static DEFINE_MUTEX(set_limit_mutex
);
3489 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
3490 unsigned long long val
)
3493 u64 memswlimit
, memlimit
;
3495 int children
= mem_cgroup_count_children(memcg
);
3496 u64 curusage
, oldusage
;
3500 * For keeping hierarchical_reclaim simple, how long we should retry
3501 * is depends on callers. We set our retry-count to be function
3502 * of # of children which we should visit in this loop.
3504 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
* children
;
3506 oldusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
3509 while (retry_count
) {
3510 if (signal_pending(current
)) {
3515 * Rather than hide all in some function, I do this in
3516 * open coded manner. You see what this really does.
3517 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3519 mutex_lock(&set_limit_mutex
);
3520 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
3521 if (memswlimit
< val
) {
3523 mutex_unlock(&set_limit_mutex
);
3527 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
3531 ret
= res_counter_set_limit(&memcg
->res
, val
);
3533 if (memswlimit
== val
)
3534 memcg
->memsw_is_minimum
= true;
3536 memcg
->memsw_is_minimum
= false;
3538 mutex_unlock(&set_limit_mutex
);
3543 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
3544 MEM_CGROUP_RECLAIM_SHRINK
);
3545 curusage
= res_counter_read_u64(&memcg
->res
, RES_USAGE
);
3546 /* Usage is reduced ? */
3547 if (curusage
>= oldusage
)
3550 oldusage
= curusage
;
3552 if (!ret
&& enlarge
)
3553 memcg_oom_recover(memcg
);
3558 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
3559 unsigned long long val
)
3562 u64 memlimit
, memswlimit
, oldusage
, curusage
;
3563 int children
= mem_cgroup_count_children(memcg
);
3567 /* see mem_cgroup_resize_res_limit */
3568 retry_count
= children
* MEM_CGROUP_RECLAIM_RETRIES
;
3569 oldusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
3570 while (retry_count
) {
3571 if (signal_pending(current
)) {
3576 * Rather than hide all in some function, I do this in
3577 * open coded manner. You see what this really does.
3578 * We have to guarantee memcg->res.limit <= memcg->memsw.limit.
3580 mutex_lock(&set_limit_mutex
);
3581 memlimit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
3582 if (memlimit
> val
) {
3584 mutex_unlock(&set_limit_mutex
);
3587 memswlimit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
3588 if (memswlimit
< val
)
3590 ret
= res_counter_set_limit(&memcg
->memsw
, val
);
3592 if (memlimit
== val
)
3593 memcg
->memsw_is_minimum
= true;
3595 memcg
->memsw_is_minimum
= false;
3597 mutex_unlock(&set_limit_mutex
);
3602 mem_cgroup_reclaim(memcg
, GFP_KERNEL
,
3603 MEM_CGROUP_RECLAIM_NOSWAP
|
3604 MEM_CGROUP_RECLAIM_SHRINK
);
3605 curusage
= res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
3606 /* Usage is reduced ? */
3607 if (curusage
>= oldusage
)
3610 oldusage
= curusage
;
3612 if (!ret
&& enlarge
)
3613 memcg_oom_recover(memcg
);
3617 unsigned long mem_cgroup_soft_limit_reclaim(struct zone
*zone
, int order
,
3619 unsigned long *total_scanned
)
3621 unsigned long nr_reclaimed
= 0;
3622 struct mem_cgroup_per_zone
*mz
, *next_mz
= NULL
;
3623 unsigned long reclaimed
;
3625 struct mem_cgroup_tree_per_zone
*mctz
;
3626 unsigned long long excess
;
3627 unsigned long nr_scanned
;
3632 mctz
= soft_limit_tree_node_zone(zone_to_nid(zone
), zone_idx(zone
));
3634 * This loop can run a while, specially if mem_cgroup's continuously
3635 * keep exceeding their soft limit and putting the system under
3642 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3647 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, zone
,
3648 gfp_mask
, &nr_scanned
);
3649 nr_reclaimed
+= reclaimed
;
3650 *total_scanned
+= nr_scanned
;
3651 spin_lock(&mctz
->lock
);
3654 * If we failed to reclaim anything from this memory cgroup
3655 * it is time to move on to the next cgroup
3661 * Loop until we find yet another one.
3663 * By the time we get the soft_limit lock
3664 * again, someone might have aded the
3665 * group back on the RB tree. Iterate to
3666 * make sure we get a different mem.
3667 * mem_cgroup_largest_soft_limit_node returns
3668 * NULL if no other cgroup is present on
3672 __mem_cgroup_largest_soft_limit_node(mctz
);
3674 css_put(&next_mz
->memcg
->css
);
3675 else /* next_mz == NULL or other memcg */
3679 __mem_cgroup_remove_exceeded(mz
->memcg
, mz
, mctz
);
3680 excess
= res_counter_soft_limit_excess(&mz
->memcg
->res
);
3682 * One school of thought says that we should not add
3683 * back the node to the tree if reclaim returns 0.
3684 * But our reclaim could return 0, simply because due
3685 * to priority we are exposing a smaller subset of
3686 * memory to reclaim from. Consider this as a longer
3689 /* If excess == 0, no tree ops */
3690 __mem_cgroup_insert_exceeded(mz
->memcg
, mz
, mctz
, excess
);
3691 spin_unlock(&mctz
->lock
);
3692 css_put(&mz
->memcg
->css
);
3695 * Could not reclaim anything and there are no more
3696 * mem cgroups to try or we seem to be looping without
3697 * reclaiming anything.
3699 if (!nr_reclaimed
&&
3701 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3703 } while (!nr_reclaimed
);
3705 css_put(&next_mz
->memcg
->css
);
3706 return nr_reclaimed
;
3710 * mem_cgroup_force_empty_list - clears LRU of a group
3711 * @memcg: group to clear
3714 * @lru: lru to to clear
3716 * Traverse a specified page_cgroup list and try to drop them all. This doesn't
3717 * reclaim the pages page themselves - pages are moved to the parent (or root)
3720 static void mem_cgroup_force_empty_list(struct mem_cgroup
*memcg
,
3721 int node
, int zid
, enum lru_list lru
)
3723 struct lruvec
*lruvec
;
3724 unsigned long flags
;
3725 struct list_head
*list
;
3729 zone
= &NODE_DATA(node
)->node_zones
[zid
];
3730 lruvec
= mem_cgroup_zone_lruvec(zone
, memcg
);
3731 list
= &lruvec
->lists
[lru
];
3735 struct page_cgroup
*pc
;
3738 spin_lock_irqsave(&zone
->lru_lock
, flags
);
3739 if (list_empty(list
)) {
3740 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
3743 page
= list_entry(list
->prev
, struct page
, lru
);
3745 list_move(&page
->lru
, list
);
3747 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
3750 spin_unlock_irqrestore(&zone
->lru_lock
, flags
);
3752 pc
= lookup_page_cgroup(page
);
3754 if (mem_cgroup_move_parent(page
, pc
, memcg
)) {
3755 /* found lock contention or "pc" is obsolete. */
3760 } while (!list_empty(list
));
3764 * make mem_cgroup's charge to be 0 if there is no task by moving
3765 * all the charges and pages to the parent.
3766 * This enables deleting this mem_cgroup.
3768 * Caller is responsible for holding css reference on the memcg.
3770 static void mem_cgroup_reparent_charges(struct mem_cgroup
*memcg
)
3775 /* This is for making all *used* pages to be on LRU. */
3776 lru_add_drain_all();
3777 drain_all_stock_sync(memcg
);
3778 mem_cgroup_start_move(memcg
);
3779 for_each_node_state(node
, N_HIGH_MEMORY
) {
3780 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
3783 mem_cgroup_force_empty_list(memcg
,
3788 mem_cgroup_end_move(memcg
);
3789 memcg_oom_recover(memcg
);
3793 * This is a safety check because mem_cgroup_force_empty_list
3794 * could have raced with mem_cgroup_replace_page_cache callers
3795 * so the lru seemed empty but the page could have been added
3796 * right after the check. RES_USAGE should be safe as we always
3797 * charge before adding to the LRU.
3799 } while (res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0);
3803 * Reclaims as many pages from the given memcg as possible and moves
3804 * the rest to the parent.
3806 * Caller is responsible for holding css reference for memcg.
3808 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3810 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
3811 struct cgroup
*cgrp
= memcg
->css
.cgroup
;
3813 /* returns EBUSY if there is a task or if we come here twice. */
3814 if (cgroup_task_count(cgrp
) || !list_empty(&cgrp
->children
))
3817 /* we call try-to-free pages for make this cgroup empty */
3818 lru_add_drain_all();
3819 /* try to free all pages in this cgroup */
3820 while (nr_retries
&& res_counter_read_u64(&memcg
->res
, RES_USAGE
) > 0) {
3823 if (signal_pending(current
))
3826 progress
= try_to_free_mem_cgroup_pages(memcg
, GFP_KERNEL
,
3830 /* maybe some writeback is necessary */
3831 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3836 mem_cgroup_reparent_charges(memcg
);
3841 static int mem_cgroup_force_empty_write(struct cgroup
*cont
, unsigned int event
)
3843 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
3846 if (mem_cgroup_is_root(memcg
))
3848 css_get(&memcg
->css
);
3849 ret
= mem_cgroup_force_empty(memcg
);
3850 css_put(&memcg
->css
);
3856 static u64
mem_cgroup_hierarchy_read(struct cgroup
*cont
, struct cftype
*cft
)
3858 return mem_cgroup_from_cont(cont
)->use_hierarchy
;
3861 static int mem_cgroup_hierarchy_write(struct cgroup
*cont
, struct cftype
*cft
,
3865 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
3866 struct cgroup
*parent
= cont
->parent
;
3867 struct mem_cgroup
*parent_memcg
= NULL
;
3870 parent_memcg
= mem_cgroup_from_cont(parent
);
3874 if (memcg
->use_hierarchy
== val
)
3878 * If parent's use_hierarchy is set, we can't make any modifications
3879 * in the child subtrees. If it is unset, then the change can
3880 * occur, provided the current cgroup has no children.
3882 * For the root cgroup, parent_mem is NULL, we allow value to be
3883 * set if there are no children.
3885 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
3886 (val
== 1 || val
== 0)) {
3887 if (list_empty(&cont
->children
))
3888 memcg
->use_hierarchy
= val
;
3901 static unsigned long mem_cgroup_recursive_stat(struct mem_cgroup
*memcg
,
3902 enum mem_cgroup_stat_index idx
)
3904 struct mem_cgroup
*iter
;
3907 /* Per-cpu values can be negative, use a signed accumulator */
3908 for_each_mem_cgroup_tree(iter
, memcg
)
3909 val
+= mem_cgroup_read_stat(iter
, idx
);
3911 if (val
< 0) /* race ? */
3916 static inline u64
mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3920 if (!mem_cgroup_is_root(memcg
)) {
3922 return res_counter_read_u64(&memcg
->res
, RES_USAGE
);
3924 return res_counter_read_u64(&memcg
->memsw
, RES_USAGE
);
3927 val
= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_CACHE
);
3928 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_RSS
);
3931 val
+= mem_cgroup_recursive_stat(memcg
, MEM_CGROUP_STAT_SWAP
);
3933 return val
<< PAGE_SHIFT
;
3936 static ssize_t
mem_cgroup_read(struct cgroup
*cont
, struct cftype
*cft
,
3937 struct file
*file
, char __user
*buf
,
3938 size_t nbytes
, loff_t
*ppos
)
3940 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
3943 int type
, name
, len
;
3945 type
= MEMFILE_TYPE(cft
->private);
3946 name
= MEMFILE_ATTR(cft
->private);
3948 if (!do_swap_account
&& type
== _MEMSWAP
)
3953 if (name
== RES_USAGE
)
3954 val
= mem_cgroup_usage(memcg
, false);
3956 val
= res_counter_read_u64(&memcg
->res
, name
);
3959 if (name
== RES_USAGE
)
3960 val
= mem_cgroup_usage(memcg
, true);
3962 val
= res_counter_read_u64(&memcg
->memsw
, name
);
3968 len
= scnprintf(str
, sizeof(str
), "%llu\n", (unsigned long long)val
);
3969 return simple_read_from_buffer(buf
, nbytes
, ppos
, str
, len
);
3972 * The user of this function is...
3975 static int mem_cgroup_write(struct cgroup
*cont
, struct cftype
*cft
,
3978 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
3980 unsigned long long val
;
3983 type
= MEMFILE_TYPE(cft
->private);
3984 name
= MEMFILE_ATTR(cft
->private);
3986 if (!do_swap_account
&& type
== _MEMSWAP
)
3991 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3995 /* This function does all necessary parse...reuse it */
3996 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
4000 ret
= mem_cgroup_resize_limit(memcg
, val
);
4002 ret
= mem_cgroup_resize_memsw_limit(memcg
, val
);
4004 case RES_SOFT_LIMIT
:
4005 ret
= res_counter_memparse_write_strategy(buffer
, &val
);
4009 * For memsw, soft limits are hard to implement in terms
4010 * of semantics, for now, we support soft limits for
4011 * control without swap
4014 ret
= res_counter_set_soft_limit(&memcg
->res
, val
);
4019 ret
= -EINVAL
; /* should be BUG() ? */
4025 static void memcg_get_hierarchical_limit(struct mem_cgroup
*memcg
,
4026 unsigned long long *mem_limit
, unsigned long long *memsw_limit
)
4028 struct cgroup
*cgroup
;
4029 unsigned long long min_limit
, min_memsw_limit
, tmp
;
4031 min_limit
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4032 min_memsw_limit
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4033 cgroup
= memcg
->css
.cgroup
;
4034 if (!memcg
->use_hierarchy
)
4037 while (cgroup
->parent
) {
4038 cgroup
= cgroup
->parent
;
4039 memcg
= mem_cgroup_from_cont(cgroup
);
4040 if (!memcg
->use_hierarchy
)
4042 tmp
= res_counter_read_u64(&memcg
->res
, RES_LIMIT
);
4043 min_limit
= min(min_limit
, tmp
);
4044 tmp
= res_counter_read_u64(&memcg
->memsw
, RES_LIMIT
);
4045 min_memsw_limit
= min(min_memsw_limit
, tmp
);
4048 *mem_limit
= min_limit
;
4049 *memsw_limit
= min_memsw_limit
;
4052 static int mem_cgroup_reset(struct cgroup
*cont
, unsigned int event
)
4054 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4057 type
= MEMFILE_TYPE(event
);
4058 name
= MEMFILE_ATTR(event
);
4060 if (!do_swap_account
&& type
== _MEMSWAP
)
4066 res_counter_reset_max(&memcg
->res
);
4068 res_counter_reset_max(&memcg
->memsw
);
4072 res_counter_reset_failcnt(&memcg
->res
);
4074 res_counter_reset_failcnt(&memcg
->memsw
);
4081 static u64
mem_cgroup_move_charge_read(struct cgroup
*cgrp
,
4084 return mem_cgroup_from_cont(cgrp
)->move_charge_at_immigrate
;
4088 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
4089 struct cftype
*cft
, u64 val
)
4091 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4093 if (val
>= (1 << NR_MOVE_TYPE
))
4096 * We check this value several times in both in can_attach() and
4097 * attach(), so we need cgroup lock to prevent this value from being
4101 memcg
->move_charge_at_immigrate
= val
;
4107 static int mem_cgroup_move_charge_write(struct cgroup
*cgrp
,
4108 struct cftype
*cft
, u64 val
)
4115 static int memcg_numa_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
4119 unsigned long total_nr
, file_nr
, anon_nr
, unevictable_nr
;
4120 unsigned long node_nr
;
4121 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4123 total_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL
);
4124 seq_printf(m
, "total=%lu", total_nr
);
4125 for_each_node_state(nid
, N_HIGH_MEMORY
) {
4126 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL
);
4127 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
4131 file_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_FILE
);
4132 seq_printf(m
, "file=%lu", file_nr
);
4133 for_each_node_state(nid
, N_HIGH_MEMORY
) {
4134 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
4136 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
4140 anon_nr
= mem_cgroup_nr_lru_pages(memcg
, LRU_ALL_ANON
);
4141 seq_printf(m
, "anon=%lu", anon_nr
);
4142 for_each_node_state(nid
, N_HIGH_MEMORY
) {
4143 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
4145 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
4149 unevictable_nr
= mem_cgroup_nr_lru_pages(memcg
, BIT(LRU_UNEVICTABLE
));
4150 seq_printf(m
, "unevictable=%lu", unevictable_nr
);
4151 for_each_node_state(nid
, N_HIGH_MEMORY
) {
4152 node_nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
4153 BIT(LRU_UNEVICTABLE
));
4154 seq_printf(m
, " N%d=%lu", nid
, node_nr
);
4159 #endif /* CONFIG_NUMA */
4161 static const char * const mem_cgroup_lru_names
[] = {
4169 static inline void mem_cgroup_lru_names_not_uptodate(void)
4171 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
4174 static int memcg_stat_show(struct cgroup
*cont
, struct cftype
*cft
,
4177 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
4178 struct mem_cgroup
*mi
;
4181 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
4182 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
4184 seq_printf(m
, "%s %ld\n", mem_cgroup_stat_names
[i
],
4185 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
4188 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
4189 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
4190 mem_cgroup_read_events(memcg
, i
));
4192 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
4193 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
4194 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
4196 /* Hierarchical information */
4198 unsigned long long limit
, memsw_limit
;
4199 memcg_get_hierarchical_limit(memcg
, &limit
, &memsw_limit
);
4200 seq_printf(m
, "hierarchical_memory_limit %llu\n", limit
);
4201 if (do_swap_account
)
4202 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
4206 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
4209 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
4211 for_each_mem_cgroup_tree(mi
, memcg
)
4212 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
4213 seq_printf(m
, "total_%s %lld\n", mem_cgroup_stat_names
[i
], val
);
4216 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
4217 unsigned long long val
= 0;
4219 for_each_mem_cgroup_tree(mi
, memcg
)
4220 val
+= mem_cgroup_read_events(mi
, i
);
4221 seq_printf(m
, "total_%s %llu\n",
4222 mem_cgroup_events_names
[i
], val
);
4225 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
4226 unsigned long long val
= 0;
4228 for_each_mem_cgroup_tree(mi
, memcg
)
4229 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
4230 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
4233 #ifdef CONFIG_DEBUG_VM
4236 struct mem_cgroup_per_zone
*mz
;
4237 struct zone_reclaim_stat
*rstat
;
4238 unsigned long recent_rotated
[2] = {0, 0};
4239 unsigned long recent_scanned
[2] = {0, 0};
4241 for_each_online_node(nid
)
4242 for (zid
= 0; zid
< MAX_NR_ZONES
; zid
++) {
4243 mz
= mem_cgroup_zoneinfo(memcg
, nid
, zid
);
4244 rstat
= &mz
->lruvec
.reclaim_stat
;
4246 recent_rotated
[0] += rstat
->recent_rotated
[0];
4247 recent_rotated
[1] += rstat
->recent_rotated
[1];
4248 recent_scanned
[0] += rstat
->recent_scanned
[0];
4249 recent_scanned
[1] += rstat
->recent_scanned
[1];
4251 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
4252 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
4253 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
4254 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
4261 static u64
mem_cgroup_swappiness_read(struct cgroup
*cgrp
, struct cftype
*cft
)
4263 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4265 return mem_cgroup_swappiness(memcg
);
4268 static int mem_cgroup_swappiness_write(struct cgroup
*cgrp
, struct cftype
*cft
,
4271 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4272 struct mem_cgroup
*parent
;
4277 if (cgrp
->parent
== NULL
)
4280 parent
= mem_cgroup_from_cont(cgrp
->parent
);
4284 /* If under hierarchy, only empty-root can set this value */
4285 if ((parent
->use_hierarchy
) ||
4286 (memcg
->use_hierarchy
&& !list_empty(&cgrp
->children
))) {
4291 memcg
->swappiness
= val
;
4298 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
4300 struct mem_cgroup_threshold_ary
*t
;
4306 t
= rcu_dereference(memcg
->thresholds
.primary
);
4308 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
4313 usage
= mem_cgroup_usage(memcg
, swap
);
4316 * current_threshold points to threshold just below or equal to usage.
4317 * If it's not true, a threshold was crossed after last
4318 * call of __mem_cgroup_threshold().
4320 i
= t
->current_threshold
;
4323 * Iterate backward over array of thresholds starting from
4324 * current_threshold and check if a threshold is crossed.
4325 * If none of thresholds below usage is crossed, we read
4326 * only one element of the array here.
4328 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
4329 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4331 /* i = current_threshold + 1 */
4335 * Iterate forward over array of thresholds starting from
4336 * current_threshold+1 and check if a threshold is crossed.
4337 * If none of thresholds above usage is crossed, we read
4338 * only one element of the array here.
4340 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
4341 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4343 /* Update current_threshold */
4344 t
->current_threshold
= i
- 1;
4349 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
4352 __mem_cgroup_threshold(memcg
, false);
4353 if (do_swap_account
)
4354 __mem_cgroup_threshold(memcg
, true);
4356 memcg
= parent_mem_cgroup(memcg
);
4360 static int compare_thresholds(const void *a
, const void *b
)
4362 const struct mem_cgroup_threshold
*_a
= a
;
4363 const struct mem_cgroup_threshold
*_b
= b
;
4365 return _a
->threshold
- _b
->threshold
;
4368 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
4370 struct mem_cgroup_eventfd_list
*ev
;
4372 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
4373 eventfd_signal(ev
->eventfd
, 1);
4377 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
4379 struct mem_cgroup
*iter
;
4381 for_each_mem_cgroup_tree(iter
, memcg
)
4382 mem_cgroup_oom_notify_cb(iter
);
4385 static int mem_cgroup_usage_register_event(struct cgroup
*cgrp
,
4386 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
4388 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4389 struct mem_cgroup_thresholds
*thresholds
;
4390 struct mem_cgroup_threshold_ary
*new;
4391 int type
= MEMFILE_TYPE(cft
->private);
4392 u64 threshold
, usage
;
4395 ret
= res_counter_memparse_write_strategy(args
, &threshold
);
4399 mutex_lock(&memcg
->thresholds_lock
);
4402 thresholds
= &memcg
->thresholds
;
4403 else if (type
== _MEMSWAP
)
4404 thresholds
= &memcg
->memsw_thresholds
;
4408 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
4410 /* Check if a threshold crossed before adding a new one */
4411 if (thresholds
->primary
)
4412 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4414 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4416 /* Allocate memory for new array of thresholds */
4417 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
4425 /* Copy thresholds (if any) to new array */
4426 if (thresholds
->primary
) {
4427 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
4428 sizeof(struct mem_cgroup_threshold
));
4431 /* Add new threshold */
4432 new->entries
[size
- 1].eventfd
= eventfd
;
4433 new->entries
[size
- 1].threshold
= threshold
;
4435 /* Sort thresholds. Registering of new threshold isn't time-critical */
4436 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
4437 compare_thresholds
, NULL
);
4439 /* Find current threshold */
4440 new->current_threshold
= -1;
4441 for (i
= 0; i
< size
; i
++) {
4442 if (new->entries
[i
].threshold
<= usage
) {
4444 * new->current_threshold will not be used until
4445 * rcu_assign_pointer(), so it's safe to increment
4448 ++new->current_threshold
;
4453 /* Free old spare buffer and save old primary buffer as spare */
4454 kfree(thresholds
->spare
);
4455 thresholds
->spare
= thresholds
->primary
;
4457 rcu_assign_pointer(thresholds
->primary
, new);
4459 /* To be sure that nobody uses thresholds */
4463 mutex_unlock(&memcg
->thresholds_lock
);
4468 static void mem_cgroup_usage_unregister_event(struct cgroup
*cgrp
,
4469 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
4471 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4472 struct mem_cgroup_thresholds
*thresholds
;
4473 struct mem_cgroup_threshold_ary
*new;
4474 int type
= MEMFILE_TYPE(cft
->private);
4478 mutex_lock(&memcg
->thresholds_lock
);
4480 thresholds
= &memcg
->thresholds
;
4481 else if (type
== _MEMSWAP
)
4482 thresholds
= &memcg
->memsw_thresholds
;
4486 if (!thresholds
->primary
)
4489 usage
= mem_cgroup_usage(memcg
, type
== _MEMSWAP
);
4491 /* Check if a threshold crossed before removing */
4492 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4494 /* Calculate new number of threshold */
4496 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4497 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4501 new = thresholds
->spare
;
4503 /* Set thresholds array to NULL if we don't have thresholds */
4512 /* Copy thresholds and find current threshold */
4513 new->current_threshold
= -1;
4514 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4515 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4518 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4519 if (new->entries
[j
].threshold
<= usage
) {
4521 * new->current_threshold will not be used
4522 * until rcu_assign_pointer(), so it's safe to increment
4525 ++new->current_threshold
;
4531 /* Swap primary and spare array */
4532 thresholds
->spare
= thresholds
->primary
;
4533 /* If all events are unregistered, free the spare array */
4535 kfree(thresholds
->spare
);
4536 thresholds
->spare
= NULL
;
4539 rcu_assign_pointer(thresholds
->primary
, new);
4541 /* To be sure that nobody uses thresholds */
4544 mutex_unlock(&memcg
->thresholds_lock
);
4547 static int mem_cgroup_oom_register_event(struct cgroup
*cgrp
,
4548 struct cftype
*cft
, struct eventfd_ctx
*eventfd
, const char *args
)
4550 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4551 struct mem_cgroup_eventfd_list
*event
;
4552 int type
= MEMFILE_TYPE(cft
->private);
4554 BUG_ON(type
!= _OOM_TYPE
);
4555 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4559 spin_lock(&memcg_oom_lock
);
4561 event
->eventfd
= eventfd
;
4562 list_add(&event
->list
, &memcg
->oom_notify
);
4564 /* already in OOM ? */
4565 if (atomic_read(&memcg
->under_oom
))
4566 eventfd_signal(eventfd
, 1);
4567 spin_unlock(&memcg_oom_lock
);
4572 static void mem_cgroup_oom_unregister_event(struct cgroup
*cgrp
,
4573 struct cftype
*cft
, struct eventfd_ctx
*eventfd
)
4575 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4576 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4577 int type
= MEMFILE_TYPE(cft
->private);
4579 BUG_ON(type
!= _OOM_TYPE
);
4581 spin_lock(&memcg_oom_lock
);
4583 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4584 if (ev
->eventfd
== eventfd
) {
4585 list_del(&ev
->list
);
4590 spin_unlock(&memcg_oom_lock
);
4593 static int mem_cgroup_oom_control_read(struct cgroup
*cgrp
,
4594 struct cftype
*cft
, struct cgroup_map_cb
*cb
)
4596 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4598 cb
->fill(cb
, "oom_kill_disable", memcg
->oom_kill_disable
);
4600 if (atomic_read(&memcg
->under_oom
))
4601 cb
->fill(cb
, "under_oom", 1);
4603 cb
->fill(cb
, "under_oom", 0);
4607 static int mem_cgroup_oom_control_write(struct cgroup
*cgrp
,
4608 struct cftype
*cft
, u64 val
)
4610 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgrp
);
4611 struct mem_cgroup
*parent
;
4613 /* cannot set to root cgroup and only 0 and 1 are allowed */
4614 if (!cgrp
->parent
|| !((val
== 0) || (val
== 1)))
4617 parent
= mem_cgroup_from_cont(cgrp
->parent
);
4620 /* oom-kill-disable is a flag for subhierarchy. */
4621 if ((parent
->use_hierarchy
) ||
4622 (memcg
->use_hierarchy
&& !list_empty(&cgrp
->children
))) {
4626 memcg
->oom_kill_disable
= val
;
4628 memcg_oom_recover(memcg
);
4633 #ifdef CONFIG_MEMCG_KMEM
4634 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
4636 return mem_cgroup_sockets_init(memcg
, ss
);
4639 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
4641 mem_cgroup_sockets_destroy(memcg
);
4644 static int memcg_init_kmem(struct mem_cgroup
*memcg
, struct cgroup_subsys
*ss
)
4649 static void kmem_cgroup_destroy(struct mem_cgroup
*memcg
)
4654 static struct cftype mem_cgroup_files
[] = {
4656 .name
= "usage_in_bytes",
4657 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4658 .read
= mem_cgroup_read
,
4659 .register_event
= mem_cgroup_usage_register_event
,
4660 .unregister_event
= mem_cgroup_usage_unregister_event
,
4663 .name
= "max_usage_in_bytes",
4664 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4665 .trigger
= mem_cgroup_reset
,
4666 .read
= mem_cgroup_read
,
4669 .name
= "limit_in_bytes",
4670 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4671 .write_string
= mem_cgroup_write
,
4672 .read
= mem_cgroup_read
,
4675 .name
= "soft_limit_in_bytes",
4676 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4677 .write_string
= mem_cgroup_write
,
4678 .read
= mem_cgroup_read
,
4682 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4683 .trigger
= mem_cgroup_reset
,
4684 .read
= mem_cgroup_read
,
4688 .read_seq_string
= memcg_stat_show
,
4691 .name
= "force_empty",
4692 .trigger
= mem_cgroup_force_empty_write
,
4695 .name
= "use_hierarchy",
4696 .write_u64
= mem_cgroup_hierarchy_write
,
4697 .read_u64
= mem_cgroup_hierarchy_read
,
4700 .name
= "swappiness",
4701 .read_u64
= mem_cgroup_swappiness_read
,
4702 .write_u64
= mem_cgroup_swappiness_write
,
4705 .name
= "move_charge_at_immigrate",
4706 .read_u64
= mem_cgroup_move_charge_read
,
4707 .write_u64
= mem_cgroup_move_charge_write
,
4710 .name
= "oom_control",
4711 .read_map
= mem_cgroup_oom_control_read
,
4712 .write_u64
= mem_cgroup_oom_control_write
,
4713 .register_event
= mem_cgroup_oom_register_event
,
4714 .unregister_event
= mem_cgroup_oom_unregister_event
,
4715 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4719 .name
= "numa_stat",
4720 .read_seq_string
= memcg_numa_stat_show
,
4723 #ifdef CONFIG_MEMCG_SWAP
4725 .name
= "memsw.usage_in_bytes",
4726 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
4727 .read
= mem_cgroup_read
,
4728 .register_event
= mem_cgroup_usage_register_event
,
4729 .unregister_event
= mem_cgroup_usage_unregister_event
,
4732 .name
= "memsw.max_usage_in_bytes",
4733 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
4734 .trigger
= mem_cgroup_reset
,
4735 .read
= mem_cgroup_read
,
4738 .name
= "memsw.limit_in_bytes",
4739 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
4740 .write_string
= mem_cgroup_write
,
4741 .read
= mem_cgroup_read
,
4744 .name
= "memsw.failcnt",
4745 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
4746 .trigger
= mem_cgroup_reset
,
4747 .read
= mem_cgroup_read
,
4750 { }, /* terminate */
4753 static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
4755 struct mem_cgroup_per_node
*pn
;
4756 struct mem_cgroup_per_zone
*mz
;
4757 int zone
, tmp
= node
;
4759 * This routine is called against possible nodes.
4760 * But it's BUG to call kmalloc() against offline node.
4762 * TODO: this routine can waste much memory for nodes which will
4763 * never be onlined. It's better to use memory hotplug callback
4766 if (!node_state(node
, N_NORMAL_MEMORY
))
4768 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4772 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
4773 mz
= &pn
->zoneinfo
[zone
];
4774 lruvec_init(&mz
->lruvec
);
4775 mz
->usage_in_excess
= 0;
4776 mz
->on_tree
= false;
4779 memcg
->info
.nodeinfo
[node
] = pn
;
4783 static void free_mem_cgroup_per_zone_info(struct mem_cgroup
*memcg
, int node
)
4785 kfree(memcg
->info
.nodeinfo
[node
]);
4788 static struct mem_cgroup
*mem_cgroup_alloc(void)
4790 struct mem_cgroup
*memcg
;
4791 int size
= sizeof(struct mem_cgroup
);
4793 /* Can be very big if MAX_NUMNODES is very big */
4794 if (size
< PAGE_SIZE
)
4795 memcg
= kzalloc(size
, GFP_KERNEL
);
4797 memcg
= vzalloc(size
);
4802 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
4805 spin_lock_init(&memcg
->pcp_counter_lock
);
4809 if (size
< PAGE_SIZE
)
4817 * Helpers for freeing a kmalloc()ed/vzalloc()ed mem_cgroup by RCU,
4818 * but in process context. The work_freeing structure is overlaid
4819 * on the rcu_freeing structure, which itself is overlaid on memsw.
4821 static void free_work(struct work_struct
*work
)
4823 struct mem_cgroup
*memcg
;
4824 int size
= sizeof(struct mem_cgroup
);
4826 memcg
= container_of(work
, struct mem_cgroup
, work_freeing
);
4828 * We need to make sure that (at least for now), the jump label
4829 * destruction code runs outside of the cgroup lock. This is because
4830 * get_online_cpus(), which is called from the static_branch update,
4831 * can't be called inside the cgroup_lock. cpusets are the ones
4832 * enforcing this dependency, so if they ever change, we might as well.
4834 * schedule_work() will guarantee this happens. Be careful if you need
4835 * to move this code around, and make sure it is outside
4838 disarm_sock_keys(memcg
);
4839 if (size
< PAGE_SIZE
)
4845 static void free_rcu(struct rcu_head
*rcu_head
)
4847 struct mem_cgroup
*memcg
;
4849 memcg
= container_of(rcu_head
, struct mem_cgroup
, rcu_freeing
);
4850 INIT_WORK(&memcg
->work_freeing
, free_work
);
4851 schedule_work(&memcg
->work_freeing
);
4855 * At destroying mem_cgroup, references from swap_cgroup can remain.
4856 * (scanning all at force_empty is too costly...)
4858 * Instead of clearing all references at force_empty, we remember
4859 * the number of reference from swap_cgroup and free mem_cgroup when
4860 * it goes down to 0.
4862 * Removal of cgroup itself succeeds regardless of refs from swap.
4865 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
4869 mem_cgroup_remove_from_trees(memcg
);
4870 free_css_id(&mem_cgroup_subsys
, &memcg
->css
);
4873 free_mem_cgroup_per_zone_info(memcg
, node
);
4875 free_percpu(memcg
->stat
);
4876 call_rcu(&memcg
->rcu_freeing
, free_rcu
);
4879 static void mem_cgroup_get(struct mem_cgroup
*memcg
)
4881 atomic_inc(&memcg
->refcnt
);
4884 static void __mem_cgroup_put(struct mem_cgroup
*memcg
, int count
)
4886 if (atomic_sub_and_test(count
, &memcg
->refcnt
)) {
4887 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
4888 __mem_cgroup_free(memcg
);
4890 mem_cgroup_put(parent
);
4894 static void mem_cgroup_put(struct mem_cgroup
*memcg
)
4896 __mem_cgroup_put(memcg
, 1);
4900 * Returns the parent mem_cgroup in memcgroup hierarchy with hierarchy enabled.
4902 struct mem_cgroup
*parent_mem_cgroup(struct mem_cgroup
*memcg
)
4904 if (!memcg
->res
.parent
)
4906 return mem_cgroup_from_res_counter(memcg
->res
.parent
, res
);
4908 EXPORT_SYMBOL(parent_mem_cgroup
);
4910 #ifdef CONFIG_MEMCG_SWAP
4911 static void __init
enable_swap_cgroup(void)
4913 if (!mem_cgroup_disabled() && really_do_swap_account
)
4914 do_swap_account
= 1;
4917 static void __init
enable_swap_cgroup(void)
4922 static int mem_cgroup_soft_limit_tree_init(void)
4924 struct mem_cgroup_tree_per_node
*rtpn
;
4925 struct mem_cgroup_tree_per_zone
*rtpz
;
4926 int tmp
, node
, zone
;
4928 for_each_node(node
) {
4930 if (!node_state(node
, N_NORMAL_MEMORY
))
4932 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
, tmp
);
4936 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
4938 for (zone
= 0; zone
< MAX_NR_ZONES
; zone
++) {
4939 rtpz
= &rtpn
->rb_tree_per_zone
[zone
];
4940 rtpz
->rb_root
= RB_ROOT
;
4941 spin_lock_init(&rtpz
->lock
);
4947 for_each_node(node
) {
4948 if (!soft_limit_tree
.rb_tree_per_node
[node
])
4950 kfree(soft_limit_tree
.rb_tree_per_node
[node
]);
4951 soft_limit_tree
.rb_tree_per_node
[node
] = NULL
;
4957 static struct cgroup_subsys_state
* __ref
4958 mem_cgroup_css_alloc(struct cgroup
*cont
)
4960 struct mem_cgroup
*memcg
, *parent
;
4961 long error
= -ENOMEM
;
4964 memcg
= mem_cgroup_alloc();
4966 return ERR_PTR(error
);
4969 if (alloc_mem_cgroup_per_zone_info(memcg
, node
))
4973 if (cont
->parent
== NULL
) {
4975 enable_swap_cgroup();
4977 if (mem_cgroup_soft_limit_tree_init())
4979 root_mem_cgroup
= memcg
;
4980 for_each_possible_cpu(cpu
) {
4981 struct memcg_stock_pcp
*stock
=
4982 &per_cpu(memcg_stock
, cpu
);
4983 INIT_WORK(&stock
->work
, drain_local_stock
);
4985 hotcpu_notifier(memcg_cpu_hotplug_callback
, 0);
4987 parent
= mem_cgroup_from_cont(cont
->parent
);
4988 memcg
->use_hierarchy
= parent
->use_hierarchy
;
4989 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
4992 if (parent
&& parent
->use_hierarchy
) {
4993 res_counter_init(&memcg
->res
, &parent
->res
);
4994 res_counter_init(&memcg
->memsw
, &parent
->memsw
);
4996 * We increment refcnt of the parent to ensure that we can
4997 * safely access it on res_counter_charge/uncharge.
4998 * This refcnt will be decremented when freeing this
4999 * mem_cgroup(see mem_cgroup_put).
5001 mem_cgroup_get(parent
);
5003 res_counter_init(&memcg
->res
, NULL
);
5004 res_counter_init(&memcg
->memsw
, NULL
);
5006 * Deeper hierachy with use_hierarchy == false doesn't make
5007 * much sense so let cgroup subsystem know about this
5008 * unfortunate state in our controller.
5010 if (parent
&& parent
!= root_mem_cgroup
)
5011 mem_cgroup_subsys
.broken_hierarchy
= true;
5013 memcg
->last_scanned_node
= MAX_NUMNODES
;
5014 INIT_LIST_HEAD(&memcg
->oom_notify
);
5017 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
5018 atomic_set(&memcg
->refcnt
, 1);
5019 memcg
->move_charge_at_immigrate
= 0;
5020 mutex_init(&memcg
->thresholds_lock
);
5021 spin_lock_init(&memcg
->move_lock
);
5023 error
= memcg_init_kmem(memcg
, &mem_cgroup_subsys
);
5026 * We call put now because our (and parent's) refcnts
5027 * are already in place. mem_cgroup_put() will internally
5028 * call __mem_cgroup_free, so return directly
5030 mem_cgroup_put(memcg
);
5031 return ERR_PTR(error
);
5035 __mem_cgroup_free(memcg
);
5036 return ERR_PTR(error
);
5039 static void mem_cgroup_css_offline(struct cgroup
*cont
)
5041 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5043 mem_cgroup_reparent_charges(memcg
);
5046 static void mem_cgroup_css_free(struct cgroup
*cont
)
5048 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cont
);
5050 kmem_cgroup_destroy(memcg
);
5052 mem_cgroup_put(memcg
);
5056 /* Handlers for move charge at task migration. */
5057 #define PRECHARGE_COUNT_AT_ONCE 256
5058 static int mem_cgroup_do_precharge(unsigned long count
)
5061 int batch_count
= PRECHARGE_COUNT_AT_ONCE
;
5062 struct mem_cgroup
*memcg
= mc
.to
;
5064 if (mem_cgroup_is_root(memcg
)) {
5065 mc
.precharge
+= count
;
5066 /* we don't need css_get for root */
5069 /* try to charge at once */
5071 struct res_counter
*dummy
;
5073 * "memcg" cannot be under rmdir() because we've already checked
5074 * by cgroup_lock_live_cgroup() that it is not removed and we
5075 * are still under the same cgroup_mutex. So we can postpone
5078 if (res_counter_charge(&memcg
->res
, PAGE_SIZE
* count
, &dummy
))
5080 if (do_swap_account
&& res_counter_charge(&memcg
->memsw
,
5081 PAGE_SIZE
* count
, &dummy
)) {
5082 res_counter_uncharge(&memcg
->res
, PAGE_SIZE
* count
);
5085 mc
.precharge
+= count
;
5089 /* fall back to one by one charge */
5091 if (signal_pending(current
)) {
5095 if (!batch_count
--) {
5096 batch_count
= PRECHARGE_COUNT_AT_ONCE
;
5099 ret
= __mem_cgroup_try_charge(NULL
,
5100 GFP_KERNEL
, 1, &memcg
, false);
5102 /* mem_cgroup_clear_mc() will do uncharge later */
5110 * get_mctgt_type - get target type of moving charge
5111 * @vma: the vma the pte to be checked belongs
5112 * @addr: the address corresponding to the pte to be checked
5113 * @ptent: the pte to be checked
5114 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5117 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5118 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5119 * move charge. if @target is not NULL, the page is stored in target->page
5120 * with extra refcnt got(Callers should handle it).
5121 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5122 * target for charge migration. if @target is not NULL, the entry is stored
5125 * Called with pte lock held.
5132 enum mc_target_type
{
5138 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
5139 unsigned long addr
, pte_t ptent
)
5141 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
5143 if (!page
|| !page_mapped(page
))
5145 if (PageAnon(page
)) {
5146 /* we don't move shared anon */
5149 } else if (!move_file())
5150 /* we ignore mapcount for file pages */
5152 if (!get_page_unless_zero(page
))
5159 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5160 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5162 struct page
*page
= NULL
;
5163 swp_entry_t ent
= pte_to_swp_entry(ptent
);
5165 if (!move_anon() || non_swap_entry(ent
))
5168 * Because lookup_swap_cache() updates some statistics counter,
5169 * we call find_get_page() with swapper_space directly.
5171 page
= find_get_page(&swapper_space
, ent
.val
);
5172 if (do_swap_account
)
5173 entry
->val
= ent
.val
;
5178 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5179 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5185 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5186 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5188 struct page
*page
= NULL
;
5189 struct address_space
*mapping
;
5192 if (!vma
->vm_file
) /* anonymous vma */
5197 mapping
= vma
->vm_file
->f_mapping
;
5198 if (pte_none(ptent
))
5199 pgoff
= linear_page_index(vma
, addr
);
5200 else /* pte_file(ptent) is true */
5201 pgoff
= pte_to_pgoff(ptent
);
5203 /* page is moved even if it's not RSS of this task(page-faulted). */
5204 page
= find_get_page(mapping
, pgoff
);
5207 /* shmem/tmpfs may report page out on swap: account for that too. */
5208 if (radix_tree_exceptional_entry(page
)) {
5209 swp_entry_t swap
= radix_to_swp_entry(page
);
5210 if (do_swap_account
)
5212 page
= find_get_page(&swapper_space
, swap
.val
);
5218 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5219 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5221 struct page
*page
= NULL
;
5222 struct page_cgroup
*pc
;
5223 enum mc_target_type ret
= MC_TARGET_NONE
;
5224 swp_entry_t ent
= { .val
= 0 };
5226 if (pte_present(ptent
))
5227 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5228 else if (is_swap_pte(ptent
))
5229 page
= mc_handle_swap_pte(vma
, addr
, ptent
, &ent
);
5230 else if (pte_none(ptent
) || pte_file(ptent
))
5231 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5233 if (!page
&& !ent
.val
)
5236 pc
= lookup_page_cgroup(page
);
5238 * Do only loose check w/o page_cgroup lock.
5239 * mem_cgroup_move_account() checks the pc is valid or not under
5242 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
5243 ret
= MC_TARGET_PAGE
;
5245 target
->page
= page
;
5247 if (!ret
|| !target
)
5250 /* There is a swap entry and a page doesn't exist or isn't charged */
5251 if (ent
.val
&& !ret
&&
5252 css_id(&mc
.from
->css
) == lookup_swap_cgroup_id(ent
)) {
5253 ret
= MC_TARGET_SWAP
;
5260 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5262 * We don't consider swapping or file mapped pages because THP does not
5263 * support them for now.
5264 * Caller should make sure that pmd_trans_huge(pmd) is true.
5266 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5267 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5269 struct page
*page
= NULL
;
5270 struct page_cgroup
*pc
;
5271 enum mc_target_type ret
= MC_TARGET_NONE
;
5273 page
= pmd_page(pmd
);
5274 VM_BUG_ON(!page
|| !PageHead(page
));
5277 pc
= lookup_page_cgroup(page
);
5278 if (PageCgroupUsed(pc
) && pc
->mem_cgroup
== mc
.from
) {
5279 ret
= MC_TARGET_PAGE
;
5282 target
->page
= page
;
5288 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5289 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5291 return MC_TARGET_NONE
;
5295 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5296 unsigned long addr
, unsigned long end
,
5297 struct mm_walk
*walk
)
5299 struct vm_area_struct
*vma
= walk
->private;
5303 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
5304 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5305 mc
.precharge
+= HPAGE_PMD_NR
;
5306 spin_unlock(&vma
->vm_mm
->page_table_lock
);
5310 if (pmd_trans_unstable(pmd
))
5312 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5313 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5314 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5315 mc
.precharge
++; /* increment precharge temporarily */
5316 pte_unmap_unlock(pte
- 1, ptl
);
5322 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5324 unsigned long precharge
;
5325 struct vm_area_struct
*vma
;
5327 down_read(&mm
->mmap_sem
);
5328 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
5329 struct mm_walk mem_cgroup_count_precharge_walk
= {
5330 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5334 if (is_vm_hugetlb_page(vma
))
5336 walk_page_range(vma
->vm_start
, vma
->vm_end
,
5337 &mem_cgroup_count_precharge_walk
);
5339 up_read(&mm
->mmap_sem
);
5341 precharge
= mc
.precharge
;
5347 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5349 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5351 VM_BUG_ON(mc
.moving_task
);
5352 mc
.moving_task
= current
;
5353 return mem_cgroup_do_precharge(precharge
);
5356 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5357 static void __mem_cgroup_clear_mc(void)
5359 struct mem_cgroup
*from
= mc
.from
;
5360 struct mem_cgroup
*to
= mc
.to
;
5362 /* we must uncharge all the leftover precharges from mc.to */
5364 __mem_cgroup_cancel_charge(mc
.to
, mc
.precharge
);
5368 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5369 * we must uncharge here.
5371 if (mc
.moved_charge
) {
5372 __mem_cgroup_cancel_charge(mc
.from
, mc
.moved_charge
);
5373 mc
.moved_charge
= 0;
5375 /* we must fixup refcnts and charges */
5376 if (mc
.moved_swap
) {
5377 /* uncharge swap account from the old cgroup */
5378 if (!mem_cgroup_is_root(mc
.from
))
5379 res_counter_uncharge(&mc
.from
->memsw
,
5380 PAGE_SIZE
* mc
.moved_swap
);
5381 __mem_cgroup_put(mc
.from
, mc
.moved_swap
);
5383 if (!mem_cgroup_is_root(mc
.to
)) {
5385 * we charged both to->res and to->memsw, so we should
5388 res_counter_uncharge(&mc
.to
->res
,
5389 PAGE_SIZE
* mc
.moved_swap
);
5391 /* we've already done mem_cgroup_get(mc.to) */
5394 memcg_oom_recover(from
);
5395 memcg_oom_recover(to
);
5396 wake_up_all(&mc
.waitq
);
5399 static void mem_cgroup_clear_mc(void)
5401 struct mem_cgroup
*from
= mc
.from
;
5404 * we must clear moving_task before waking up waiters at the end of
5407 mc
.moving_task
= NULL
;
5408 __mem_cgroup_clear_mc();
5409 spin_lock(&mc
.lock
);
5412 spin_unlock(&mc
.lock
);
5413 mem_cgroup_end_move(from
);
5416 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
5417 struct cgroup_taskset
*tset
)
5419 struct task_struct
*p
= cgroup_taskset_first(tset
);
5421 struct mem_cgroup
*memcg
= mem_cgroup_from_cont(cgroup
);
5423 if (memcg
->move_charge_at_immigrate
) {
5424 struct mm_struct
*mm
;
5425 struct mem_cgroup
*from
= mem_cgroup_from_task(p
);
5427 VM_BUG_ON(from
== memcg
);
5429 mm
= get_task_mm(p
);
5432 /* We move charges only when we move a owner of the mm */
5433 if (mm
->owner
== p
) {
5436 VM_BUG_ON(mc
.precharge
);
5437 VM_BUG_ON(mc
.moved_charge
);
5438 VM_BUG_ON(mc
.moved_swap
);
5439 mem_cgroup_start_move(from
);
5440 spin_lock(&mc
.lock
);
5443 spin_unlock(&mc
.lock
);
5444 /* We set mc.moving_task later */
5446 ret
= mem_cgroup_precharge_mc(mm
);
5448 mem_cgroup_clear_mc();
5455 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
5456 struct cgroup_taskset
*tset
)
5458 mem_cgroup_clear_mc();
5461 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
5462 unsigned long addr
, unsigned long end
,
5463 struct mm_walk
*walk
)
5466 struct vm_area_struct
*vma
= walk
->private;
5469 enum mc_target_type target_type
;
5470 union mc_target target
;
5472 struct page_cgroup
*pc
;
5475 * We don't take compound_lock() here but no race with splitting thp
5477 * - if pmd_trans_huge_lock() returns 1, the relevant thp is not
5478 * under splitting, which means there's no concurrent thp split,
5479 * - if another thread runs into split_huge_page() just after we
5480 * entered this if-block, the thread must wait for page table lock
5481 * to be unlocked in __split_huge_page_splitting(), where the main
5482 * part of thp split is not executed yet.
5484 if (pmd_trans_huge_lock(pmd
, vma
) == 1) {
5485 if (mc
.precharge
< HPAGE_PMD_NR
) {
5486 spin_unlock(&vma
->vm_mm
->page_table_lock
);
5489 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
5490 if (target_type
== MC_TARGET_PAGE
) {
5492 if (!isolate_lru_page(page
)) {
5493 pc
= lookup_page_cgroup(page
);
5494 if (!mem_cgroup_move_account(page
, HPAGE_PMD_NR
,
5495 pc
, mc
.from
, mc
.to
)) {
5496 mc
.precharge
-= HPAGE_PMD_NR
;
5497 mc
.moved_charge
+= HPAGE_PMD_NR
;
5499 putback_lru_page(page
);
5503 spin_unlock(&vma
->vm_mm
->page_table_lock
);
5507 if (pmd_trans_unstable(pmd
))
5510 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5511 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
5512 pte_t ptent
= *(pte
++);
5518 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
5519 case MC_TARGET_PAGE
:
5521 if (isolate_lru_page(page
))
5523 pc
= lookup_page_cgroup(page
);
5524 if (!mem_cgroup_move_account(page
, 1, pc
,
5527 /* we uncharge from mc.from later. */
5530 putback_lru_page(page
);
5531 put
: /* get_mctgt_type() gets the page */
5534 case MC_TARGET_SWAP
:
5536 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
5538 /* we fixup refcnts and charges later. */
5546 pte_unmap_unlock(pte
- 1, ptl
);
5551 * We have consumed all precharges we got in can_attach().
5552 * We try charge one by one, but don't do any additional
5553 * charges to mc.to if we have failed in charge once in attach()
5556 ret
= mem_cgroup_do_precharge(1);
5564 static void mem_cgroup_move_charge(struct mm_struct
*mm
)
5566 struct vm_area_struct
*vma
;
5568 lru_add_drain_all();
5570 if (unlikely(!down_read_trylock(&mm
->mmap_sem
))) {
5572 * Someone who are holding the mmap_sem might be waiting in
5573 * waitq. So we cancel all extra charges, wake up all waiters,
5574 * and retry. Because we cancel precharges, we might not be able
5575 * to move enough charges, but moving charge is a best-effort
5576 * feature anyway, so it wouldn't be a big problem.
5578 __mem_cgroup_clear_mc();
5582 for (vma
= mm
->mmap
; vma
; vma
= vma
->vm_next
) {
5584 struct mm_walk mem_cgroup_move_charge_walk
= {
5585 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
5589 if (is_vm_hugetlb_page(vma
))
5591 ret
= walk_page_range(vma
->vm_start
, vma
->vm_end
,
5592 &mem_cgroup_move_charge_walk
);
5595 * means we have consumed all precharges and failed in
5596 * doing additional charge. Just abandon here.
5600 up_read(&mm
->mmap_sem
);
5603 static void mem_cgroup_move_task(struct cgroup
*cont
,
5604 struct cgroup_taskset
*tset
)
5606 struct task_struct
*p
= cgroup_taskset_first(tset
);
5607 struct mm_struct
*mm
= get_task_mm(p
);
5611 mem_cgroup_move_charge(mm
);
5615 mem_cgroup_clear_mc();
5617 #else /* !CONFIG_MMU */
5618 static int mem_cgroup_can_attach(struct cgroup
*cgroup
,
5619 struct cgroup_taskset
*tset
)
5623 static void mem_cgroup_cancel_attach(struct cgroup
*cgroup
,
5624 struct cgroup_taskset
*tset
)
5627 static void mem_cgroup_move_task(struct cgroup
*cont
,
5628 struct cgroup_taskset
*tset
)
5633 struct cgroup_subsys mem_cgroup_subsys
= {
5635 .subsys_id
= mem_cgroup_subsys_id
,
5636 .css_alloc
= mem_cgroup_css_alloc
,
5637 .css_offline
= mem_cgroup_css_offline
,
5638 .css_free
= mem_cgroup_css_free
,
5639 .can_attach
= mem_cgroup_can_attach
,
5640 .cancel_attach
= mem_cgroup_cancel_attach
,
5641 .attach
= mem_cgroup_move_task
,
5642 .base_cftypes
= mem_cgroup_files
,
5647 #ifdef CONFIG_MEMCG_SWAP
5648 static int __init
enable_swap_account(char *s
)
5650 /* consider enabled if no parameter or 1 is given */
5651 if (!strcmp(s
, "1"))
5652 really_do_swap_account
= 1;
5653 else if (!strcmp(s
, "0"))
5654 really_do_swap_account
= 0;
5657 __setup("swapaccount=", enable_swap_account
);