1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
18 * Charge lifetime sanitation
19 * Lockless page tracking & accounting
20 * Unified hierarchy configuration model
21 * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
23 * This program is free software; you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License as published by
25 * the Free Software Foundation; either version 2 of the License, or
26 * (at your option) any later version.
28 * This program is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 * GNU General Public License for more details.
34 #include <linux/page_counter.h>
35 #include <linux/memcontrol.h>
36 #include <linux/cgroup.h>
38 #include <linux/hugetlb.h>
39 #include <linux/pagemap.h>
40 #include <linux/smp.h>
41 #include <linux/page-flags.h>
42 #include <linux/backing-dev.h>
43 #include <linux/bit_spinlock.h>
44 #include <linux/rcupdate.h>
45 #include <linux/limits.h>
46 #include <linux/export.h>
47 #include <linux/mutex.h>
48 #include <linux/rbtree.h>
49 #include <linux/slab.h>
50 #include <linux/swap.h>
51 #include <linux/swapops.h>
52 #include <linux/spinlock.h>
53 #include <linux/eventfd.h>
54 #include <linux/poll.h>
55 #include <linux/sort.h>
57 #include <linux/seq_file.h>
58 #include <linux/vmpressure.h>
59 #include <linux/mm_inline.h>
60 #include <linux/swap_cgroup.h>
61 #include <linux/cpu.h>
62 #include <linux/oom.h>
63 #include <linux/lockdep.h>
64 #include <linux/file.h>
65 #include <linux/tracehook.h>
71 #include <linux/uaccess.h>
73 #include <trace/events/vmscan.h>
75 struct cgroup_subsys memory_cgrp_subsys __read_mostly
;
76 EXPORT_SYMBOL(memory_cgrp_subsys
);
78 struct mem_cgroup
*root_mem_cgroup __read_mostly
;
80 #define MEM_CGROUP_RECLAIM_RETRIES 5
82 /* Socket memory accounting disabled? */
83 static bool cgroup_memory_nosocket
;
85 /* Kernel memory accounting disabled? */
86 static bool cgroup_memory_nokmem
;
88 /* Whether the swap controller is active */
89 #ifdef CONFIG_MEMCG_SWAP
90 int do_swap_account __read_mostly
;
92 #define do_swap_account 0
95 /* Whether legacy memory+swap accounting is active */
96 static bool do_memsw_account(void)
98 return !cgroup_subsys_on_dfl(memory_cgrp_subsys
) && do_swap_account
;
101 static const char * const mem_cgroup_stat_names
[] = {
111 static const char * const mem_cgroup_events_names
[] = {
118 static const char * const mem_cgroup_lru_names
[] = {
126 #define THRESHOLDS_EVENTS_TARGET 128
127 #define SOFTLIMIT_EVENTS_TARGET 1024
128 #define NUMAINFO_EVENTS_TARGET 1024
131 * Cgroups above their limits are maintained in a RB-Tree, independent of
132 * their hierarchy representation
135 struct mem_cgroup_tree_per_node
{
136 struct rb_root rb_root
;
140 struct mem_cgroup_tree
{
141 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
144 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
147 struct mem_cgroup_eventfd_list
{
148 struct list_head list
;
149 struct eventfd_ctx
*eventfd
;
153 * cgroup_event represents events which userspace want to receive.
155 struct mem_cgroup_event
{
157 * memcg which the event belongs to.
159 struct mem_cgroup
*memcg
;
161 * eventfd to signal userspace about the event.
163 struct eventfd_ctx
*eventfd
;
165 * Each of these stored in a list by the cgroup.
167 struct list_head list
;
169 * register_event() callback will be used to add new userspace
170 * waiter for changes related to this event. Use eventfd_signal()
171 * on eventfd to send notification to userspace.
173 int (*register_event
)(struct mem_cgroup
*memcg
,
174 struct eventfd_ctx
*eventfd
, const char *args
);
176 * unregister_event() callback will be called when userspace closes
177 * the eventfd or on cgroup removing. This callback must be set,
178 * if you want provide notification functionality.
180 void (*unregister_event
)(struct mem_cgroup
*memcg
,
181 struct eventfd_ctx
*eventfd
);
183 * All fields below needed to unregister event when
184 * userspace closes eventfd.
187 wait_queue_head_t
*wqh
;
189 struct work_struct remove
;
192 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
193 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
195 /* Stuffs for move charges at task migration. */
197 * Types of charges to be moved.
199 #define MOVE_ANON 0x1U
200 #define MOVE_FILE 0x2U
201 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
203 /* "mc" and its members are protected by cgroup_mutex */
204 static struct move_charge_struct
{
205 spinlock_t lock
; /* for from, to */
206 struct mm_struct
*mm
;
207 struct mem_cgroup
*from
;
208 struct mem_cgroup
*to
;
210 unsigned long precharge
;
211 unsigned long moved_charge
;
212 unsigned long moved_swap
;
213 struct task_struct
*moving_task
; /* a task moving charges */
214 wait_queue_head_t waitq
; /* a waitq for other context */
216 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
217 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
221 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
222 * limit reclaim to prevent infinite loops, if they ever occur.
224 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
225 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
228 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
229 MEM_CGROUP_CHARGE_TYPE_ANON
,
230 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
231 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
235 /* for encoding cft->private value on file */
244 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
245 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
246 #define MEMFILE_ATTR(val) ((val) & 0xffff)
247 /* Used for OOM nofiier */
248 #define OOM_CONTROL (0)
250 /* Some nice accessors for the vmpressure. */
251 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
254 memcg
= root_mem_cgroup
;
255 return &memcg
->vmpressure
;
258 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
260 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
263 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
265 return (memcg
== root_mem_cgroup
);
270 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
271 * The main reason for not using cgroup id for this:
272 * this works better in sparse environments, where we have a lot of memcgs,
273 * but only a few kmem-limited. Or also, if we have, for instance, 200
274 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
275 * 200 entry array for that.
277 * The current size of the caches array is stored in memcg_nr_cache_ids. It
278 * will double each time we have to increase it.
280 static DEFINE_IDA(memcg_cache_ida
);
281 int memcg_nr_cache_ids
;
283 /* Protects memcg_nr_cache_ids */
284 static DECLARE_RWSEM(memcg_cache_ids_sem
);
286 void memcg_get_cache_ids(void)
288 down_read(&memcg_cache_ids_sem
);
291 void memcg_put_cache_ids(void)
293 up_read(&memcg_cache_ids_sem
);
297 * MIN_SIZE is different than 1, because we would like to avoid going through
298 * the alloc/free process all the time. In a small machine, 4 kmem-limited
299 * cgroups is a reasonable guess. In the future, it could be a parameter or
300 * tunable, but that is strictly not necessary.
302 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
303 * this constant directly from cgroup, but it is understandable that this is
304 * better kept as an internal representation in cgroup.c. In any case, the
305 * cgrp_id space is not getting any smaller, and we don't have to necessarily
306 * increase ours as well if it increases.
308 #define MEMCG_CACHES_MIN_SIZE 4
309 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
312 * A lot of the calls to the cache allocation functions are expected to be
313 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
314 * conditional to this static branch, we'll have to allow modules that does
315 * kmem_cache_alloc and the such to see this symbol as well
317 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
318 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
320 struct workqueue_struct
*memcg_kmem_cache_wq
;
322 #endif /* !CONFIG_SLOB */
325 * mem_cgroup_css_from_page - css of the memcg associated with a page
326 * @page: page of interest
328 * If memcg is bound to the default hierarchy, css of the memcg associated
329 * with @page is returned. The returned css remains associated with @page
330 * until it is released.
332 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
335 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
337 struct mem_cgroup
*memcg
;
339 memcg
= page
->mem_cgroup
;
341 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
342 memcg
= root_mem_cgroup
;
348 * page_cgroup_ino - return inode number of the memcg a page is charged to
351 * Look up the closest online ancestor of the memory cgroup @page is charged to
352 * and return its inode number or 0 if @page is not charged to any cgroup. It
353 * is safe to call this function without holding a reference to @page.
355 * Note, this function is inherently racy, because there is nothing to prevent
356 * the cgroup inode from getting torn down and potentially reallocated a moment
357 * after page_cgroup_ino() returns, so it only should be used by callers that
358 * do not care (such as procfs interfaces).
360 ino_t
page_cgroup_ino(struct page
*page
)
362 struct mem_cgroup
*memcg
;
363 unsigned long ino
= 0;
366 memcg
= READ_ONCE(page
->mem_cgroup
);
367 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
368 memcg
= parent_mem_cgroup(memcg
);
370 ino
= cgroup_ino(memcg
->css
.cgroup
);
375 static struct mem_cgroup_per_node
*
376 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
378 int nid
= page_to_nid(page
);
380 return memcg
->nodeinfo
[nid
];
383 static struct mem_cgroup_tree_per_node
*
384 soft_limit_tree_node(int nid
)
386 return soft_limit_tree
.rb_tree_per_node
[nid
];
389 static struct mem_cgroup_tree_per_node
*
390 soft_limit_tree_from_page(struct page
*page
)
392 int nid
= page_to_nid(page
);
394 return soft_limit_tree
.rb_tree_per_node
[nid
];
397 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
398 struct mem_cgroup_tree_per_node
*mctz
,
399 unsigned long new_usage_in_excess
)
401 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
402 struct rb_node
*parent
= NULL
;
403 struct mem_cgroup_per_node
*mz_node
;
408 mz
->usage_in_excess
= new_usage_in_excess
;
409 if (!mz
->usage_in_excess
)
413 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
415 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
418 * We can't avoid mem cgroups that are over their soft
419 * limit by the same amount
421 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
424 rb_link_node(&mz
->tree_node
, parent
, p
);
425 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
429 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
430 struct mem_cgroup_tree_per_node
*mctz
)
434 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
438 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
439 struct mem_cgroup_tree_per_node
*mctz
)
443 spin_lock_irqsave(&mctz
->lock
, flags
);
444 __mem_cgroup_remove_exceeded(mz
, mctz
);
445 spin_unlock_irqrestore(&mctz
->lock
, flags
);
448 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
450 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
451 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
452 unsigned long excess
= 0;
454 if (nr_pages
> soft_limit
)
455 excess
= nr_pages
- soft_limit
;
460 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
462 unsigned long excess
;
463 struct mem_cgroup_per_node
*mz
;
464 struct mem_cgroup_tree_per_node
*mctz
;
466 mctz
= soft_limit_tree_from_page(page
);
468 * Necessary to update all ancestors when hierarchy is used.
469 * because their event counter is not touched.
471 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
472 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
473 excess
= soft_limit_excess(memcg
);
475 * We have to update the tree if mz is on RB-tree or
476 * mem is over its softlimit.
478 if (excess
|| mz
->on_tree
) {
481 spin_lock_irqsave(&mctz
->lock
, flags
);
482 /* if on-tree, remove it */
484 __mem_cgroup_remove_exceeded(mz
, mctz
);
486 * Insert again. mz->usage_in_excess will be updated.
487 * If excess is 0, no tree ops.
489 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
490 spin_unlock_irqrestore(&mctz
->lock
, flags
);
495 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
497 struct mem_cgroup_tree_per_node
*mctz
;
498 struct mem_cgroup_per_node
*mz
;
502 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
503 mctz
= soft_limit_tree_node(nid
);
504 mem_cgroup_remove_exceeded(mz
, mctz
);
508 static struct mem_cgroup_per_node
*
509 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
511 struct rb_node
*rightmost
= NULL
;
512 struct mem_cgroup_per_node
*mz
;
516 rightmost
= rb_last(&mctz
->rb_root
);
518 goto done
; /* Nothing to reclaim from */
520 mz
= rb_entry(rightmost
, struct mem_cgroup_per_node
, tree_node
);
522 * Remove the node now but someone else can add it back,
523 * we will to add it back at the end of reclaim to its correct
524 * position in the tree.
526 __mem_cgroup_remove_exceeded(mz
, mctz
);
527 if (!soft_limit_excess(mz
->memcg
) ||
528 !css_tryget_online(&mz
->memcg
->css
))
534 static struct mem_cgroup_per_node
*
535 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
537 struct mem_cgroup_per_node
*mz
;
539 spin_lock_irq(&mctz
->lock
);
540 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
541 spin_unlock_irq(&mctz
->lock
);
546 * Return page count for single (non recursive) @memcg.
548 * Implementation Note: reading percpu statistics for memcg.
550 * Both of vmstat[] and percpu_counter has threshold and do periodic
551 * synchronization to implement "quick" read. There are trade-off between
552 * reading cost and precision of value. Then, we may have a chance to implement
553 * a periodic synchronization of counter in memcg's counter.
555 * But this _read() function is used for user interface now. The user accounts
556 * memory usage by memory cgroup and he _always_ requires exact value because
557 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
558 * have to visit all online cpus and make sum. So, for now, unnecessary
559 * synchronization is not implemented. (just implemented for cpu hotplug)
561 * If there are kernel internal actions which can make use of some not-exact
562 * value, and reading all cpu value can be performance bottleneck in some
563 * common workload, threshold and synchronization as vmstat[] should be
567 mem_cgroup_read_stat(struct mem_cgroup
*memcg
, enum mem_cgroup_stat_index idx
)
572 /* Per-cpu values can be negative, use a signed accumulator */
573 for_each_possible_cpu(cpu
)
574 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
576 * Summing races with updates, so val may be negative. Avoid exposing
577 * transient negative values.
584 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
585 enum mem_cgroup_events_index idx
)
587 unsigned long val
= 0;
590 for_each_possible_cpu(cpu
)
591 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
595 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
597 bool compound
, int nr_pages
)
600 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
601 * counted as CACHE even if it's on ANON LRU.
604 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
607 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
611 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
612 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
616 /* pagein of a big page is an event. So, ignore page size */
618 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
620 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
621 nr_pages
= -nr_pages
; /* for event */
624 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
627 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
628 int nid
, unsigned int lru_mask
)
630 struct lruvec
*lruvec
= mem_cgroup_lruvec(NODE_DATA(nid
), memcg
);
631 unsigned long nr
= 0;
634 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
637 if (!(BIT(lru
) & lru_mask
))
639 nr
+= mem_cgroup_get_lru_size(lruvec
, lru
);
644 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
645 unsigned int lru_mask
)
647 unsigned long nr
= 0;
650 for_each_node_state(nid
, N_MEMORY
)
651 nr
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
655 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
656 enum mem_cgroup_events_target target
)
658 unsigned long val
, next
;
660 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
661 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
662 /* from time_after() in jiffies.h */
663 if ((long)next
- (long)val
< 0) {
665 case MEM_CGROUP_TARGET_THRESH
:
666 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
668 case MEM_CGROUP_TARGET_SOFTLIMIT
:
669 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
671 case MEM_CGROUP_TARGET_NUMAINFO
:
672 next
= val
+ NUMAINFO_EVENTS_TARGET
;
677 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
684 * Check events in order.
687 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
689 /* threshold event is triggered in finer grain than soft limit */
690 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
691 MEM_CGROUP_TARGET_THRESH
))) {
693 bool do_numainfo __maybe_unused
;
695 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
696 MEM_CGROUP_TARGET_SOFTLIMIT
);
698 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
699 MEM_CGROUP_TARGET_NUMAINFO
);
701 mem_cgroup_threshold(memcg
);
702 if (unlikely(do_softlimit
))
703 mem_cgroup_update_tree(memcg
, page
);
705 if (unlikely(do_numainfo
))
706 atomic_inc(&memcg
->numainfo_events
);
711 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
714 * mm_update_next_owner() may clear mm->owner to NULL
715 * if it races with swapoff, page migration, etc.
716 * So this can be called with p == NULL.
721 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
723 EXPORT_SYMBOL(mem_cgroup_from_task
);
725 static struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
727 struct mem_cgroup
*memcg
= NULL
;
732 * Page cache insertions can happen withou an
733 * actual mm context, e.g. during disk probing
734 * on boot, loopback IO, acct() writes etc.
737 memcg
= root_mem_cgroup
;
739 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
740 if (unlikely(!memcg
))
741 memcg
= root_mem_cgroup
;
743 } while (!css_tryget_online(&memcg
->css
));
749 * mem_cgroup_iter - iterate over memory cgroup hierarchy
750 * @root: hierarchy root
751 * @prev: previously returned memcg, NULL on first invocation
752 * @reclaim: cookie for shared reclaim walks, NULL for full walks
754 * Returns references to children of the hierarchy below @root, or
755 * @root itself, or %NULL after a full round-trip.
757 * Caller must pass the return value in @prev on subsequent
758 * invocations for reference counting, or use mem_cgroup_iter_break()
759 * to cancel a hierarchy walk before the round-trip is complete.
761 * Reclaimers can specify a zone and a priority level in @reclaim to
762 * divide up the memcgs in the hierarchy among all concurrent
763 * reclaimers operating on the same zone and priority.
765 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
766 struct mem_cgroup
*prev
,
767 struct mem_cgroup_reclaim_cookie
*reclaim
)
769 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
770 struct cgroup_subsys_state
*css
= NULL
;
771 struct mem_cgroup
*memcg
= NULL
;
772 struct mem_cgroup
*pos
= NULL
;
774 if (mem_cgroup_disabled())
778 root
= root_mem_cgroup
;
780 if (prev
&& !reclaim
)
783 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
792 struct mem_cgroup_per_node
*mz
;
794 mz
= mem_cgroup_nodeinfo(root
, reclaim
->pgdat
->node_id
);
795 iter
= &mz
->iter
[reclaim
->priority
];
797 if (prev
&& reclaim
->generation
!= iter
->generation
)
801 pos
= READ_ONCE(iter
->position
);
802 if (!pos
|| css_tryget(&pos
->css
))
805 * css reference reached zero, so iter->position will
806 * be cleared by ->css_released. However, we should not
807 * rely on this happening soon, because ->css_released
808 * is called from a work queue, and by busy-waiting we
809 * might block it. So we clear iter->position right
812 (void)cmpxchg(&iter
->position
, pos
, NULL
);
820 css
= css_next_descendant_pre(css
, &root
->css
);
823 * Reclaimers share the hierarchy walk, and a
824 * new one might jump in right at the end of
825 * the hierarchy - make sure they see at least
826 * one group and restart from the beginning.
834 * Verify the css and acquire a reference. The root
835 * is provided by the caller, so we know it's alive
836 * and kicking, and don't take an extra reference.
838 memcg
= mem_cgroup_from_css(css
);
840 if (css
== &root
->css
)
851 * The position could have already been updated by a competing
852 * thread, so check that the value hasn't changed since we read
853 * it to avoid reclaiming from the same cgroup twice.
855 (void)cmpxchg(&iter
->position
, pos
, memcg
);
863 reclaim
->generation
= iter
->generation
;
869 if (prev
&& prev
!= root
)
876 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
877 * @root: hierarchy root
878 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
880 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
881 struct mem_cgroup
*prev
)
884 root
= root_mem_cgroup
;
885 if (prev
&& prev
!= root
)
889 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
891 struct mem_cgroup
*memcg
= dead_memcg
;
892 struct mem_cgroup_reclaim_iter
*iter
;
893 struct mem_cgroup_per_node
*mz
;
897 while ((memcg
= parent_mem_cgroup(memcg
))) {
899 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
900 for (i
= 0; i
<= DEF_PRIORITY
; i
++) {
902 cmpxchg(&iter
->position
,
910 * Iteration constructs for visiting all cgroups (under a tree). If
911 * loops are exited prematurely (break), mem_cgroup_iter_break() must
912 * be used for reference counting.
914 #define for_each_mem_cgroup_tree(iter, root) \
915 for (iter = mem_cgroup_iter(root, NULL, NULL); \
917 iter = mem_cgroup_iter(root, iter, NULL))
919 #define for_each_mem_cgroup(iter) \
920 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
922 iter = mem_cgroup_iter(NULL, iter, NULL))
925 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
926 * @memcg: hierarchy root
927 * @fn: function to call for each task
928 * @arg: argument passed to @fn
930 * This function iterates over tasks attached to @memcg or to any of its
931 * descendants and calls @fn for each task. If @fn returns a non-zero
932 * value, the function breaks the iteration loop and returns the value.
933 * Otherwise, it will iterate over all tasks and return 0.
935 * This function must not be called for the root memory cgroup.
937 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
938 int (*fn
)(struct task_struct
*, void *), void *arg
)
940 struct mem_cgroup
*iter
;
943 BUG_ON(memcg
== root_mem_cgroup
);
945 for_each_mem_cgroup_tree(iter
, memcg
) {
946 struct css_task_iter it
;
947 struct task_struct
*task
;
949 css_task_iter_start(&iter
->css
, &it
);
950 while (!ret
&& (task
= css_task_iter_next(&it
)))
952 css_task_iter_end(&it
);
954 mem_cgroup_iter_break(memcg
, iter
);
962 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
964 * @zone: zone of the page
966 * This function is only safe when following the LRU page isolation
967 * and putback protocol: the LRU lock must be held, and the page must
968 * either be PageLRU() or the caller must have isolated/allocated it.
970 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct pglist_data
*pgdat
)
972 struct mem_cgroup_per_node
*mz
;
973 struct mem_cgroup
*memcg
;
974 struct lruvec
*lruvec
;
976 if (mem_cgroup_disabled()) {
977 lruvec
= &pgdat
->lruvec
;
981 memcg
= page
->mem_cgroup
;
983 * Swapcache readahead pages are added to the LRU - and
984 * possibly migrated - before they are charged.
987 memcg
= root_mem_cgroup
;
989 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
990 lruvec
= &mz
->lruvec
;
993 * Since a node can be onlined after the mem_cgroup was created,
994 * we have to be prepared to initialize lruvec->zone here;
995 * and if offlined then reonlined, we need to reinitialize it.
997 if (unlikely(lruvec
->pgdat
!= pgdat
))
998 lruvec
->pgdat
= pgdat
;
1003 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1004 * @lruvec: mem_cgroup per zone lru vector
1005 * @lru: index of lru list the page is sitting on
1006 * @zid: zone id of the accounted pages
1007 * @nr_pages: positive when adding or negative when removing
1009 * This function must be called under lru_lock, just before a page is added
1010 * to or just after a page is removed from an lru list (that ordering being
1011 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1013 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1014 int zid
, int nr_pages
)
1016 struct mem_cgroup_per_node
*mz
;
1017 unsigned long *lru_size
;
1020 if (mem_cgroup_disabled())
1023 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1024 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1027 *lru_size
+= nr_pages
;
1030 if (WARN_ONCE(size
< 0,
1031 "%s(%p, %d, %d): lru_size %ld\n",
1032 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1038 *lru_size
+= nr_pages
;
1041 bool task_in_mem_cgroup(struct task_struct
*task
, struct mem_cgroup
*memcg
)
1043 struct mem_cgroup
*task_memcg
;
1044 struct task_struct
*p
;
1047 p
= find_lock_task_mm(task
);
1049 task_memcg
= get_mem_cgroup_from_mm(p
->mm
);
1053 * All threads may have already detached their mm's, but the oom
1054 * killer still needs to detect if they have already been oom
1055 * killed to prevent needlessly killing additional tasks.
1058 task_memcg
= mem_cgroup_from_task(task
);
1059 css_get(&task_memcg
->css
);
1062 ret
= mem_cgroup_is_descendant(task_memcg
, memcg
);
1063 css_put(&task_memcg
->css
);
1068 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1069 * @memcg: the memory cgroup
1071 * Returns the maximum amount of memory @mem can be charged with, in
1074 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1076 unsigned long margin
= 0;
1077 unsigned long count
;
1078 unsigned long limit
;
1080 count
= page_counter_read(&memcg
->memory
);
1081 limit
= READ_ONCE(memcg
->memory
.limit
);
1083 margin
= limit
- count
;
1085 if (do_memsw_account()) {
1086 count
= page_counter_read(&memcg
->memsw
);
1087 limit
= READ_ONCE(memcg
->memsw
.limit
);
1089 margin
= min(margin
, limit
- count
);
1098 * A routine for checking "mem" is under move_account() or not.
1100 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1101 * moving cgroups. This is for waiting at high-memory pressure
1104 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1106 struct mem_cgroup
*from
;
1107 struct mem_cgroup
*to
;
1110 * Unlike task_move routines, we access mc.to, mc.from not under
1111 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1113 spin_lock(&mc
.lock
);
1119 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1120 mem_cgroup_is_descendant(to
, memcg
);
1122 spin_unlock(&mc
.lock
);
1126 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1128 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1129 if (mem_cgroup_under_move(memcg
)) {
1131 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1132 /* moving charge context might have finished. */
1135 finish_wait(&mc
.waitq
, &wait
);
1142 #define K(x) ((x) << (PAGE_SHIFT-10))
1144 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1145 * @memcg: The memory cgroup that went over limit
1146 * @p: Task that is going to be killed
1148 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1151 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1153 struct mem_cgroup
*iter
;
1159 pr_info("Task in ");
1160 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1161 pr_cont(" killed as a result of limit of ");
1163 pr_info("Memory limit reached of cgroup ");
1166 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1171 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1172 K((u64
)page_counter_read(&memcg
->memory
)),
1173 K((u64
)memcg
->memory
.limit
), memcg
->memory
.failcnt
);
1174 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1175 K((u64
)page_counter_read(&memcg
->memsw
)),
1176 K((u64
)memcg
->memsw
.limit
), memcg
->memsw
.failcnt
);
1177 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1178 K((u64
)page_counter_read(&memcg
->kmem
)),
1179 K((u64
)memcg
->kmem
.limit
), memcg
->kmem
.failcnt
);
1181 for_each_mem_cgroup_tree(iter
, memcg
) {
1182 pr_info("Memory cgroup stats for ");
1183 pr_cont_cgroup_path(iter
->css
.cgroup
);
1186 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1187 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1189 pr_cont(" %s:%luKB", mem_cgroup_stat_names
[i
],
1190 K(mem_cgroup_read_stat(iter
, i
)));
1193 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1194 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1195 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1202 * This function returns the number of memcg under hierarchy tree. Returns
1203 * 1(self count) if no children.
1205 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1208 struct mem_cgroup
*iter
;
1210 for_each_mem_cgroup_tree(iter
, memcg
)
1216 * Return the memory (and swap, if configured) limit for a memcg.
1218 unsigned long mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1220 unsigned long limit
;
1222 limit
= memcg
->memory
.limit
;
1223 if (mem_cgroup_swappiness(memcg
)) {
1224 unsigned long memsw_limit
;
1225 unsigned long swap_limit
;
1227 memsw_limit
= memcg
->memsw
.limit
;
1228 swap_limit
= memcg
->swap
.limit
;
1229 swap_limit
= min(swap_limit
, (unsigned long)total_swap_pages
);
1230 limit
= min(limit
+ swap_limit
, memsw_limit
);
1235 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1238 struct oom_control oc
= {
1242 .gfp_mask
= gfp_mask
,
1247 mutex_lock(&oom_lock
);
1248 ret
= out_of_memory(&oc
);
1249 mutex_unlock(&oom_lock
);
1253 #if MAX_NUMNODES > 1
1256 * test_mem_cgroup_node_reclaimable
1257 * @memcg: the target memcg
1258 * @nid: the node ID to be checked.
1259 * @noswap : specify true here if the user wants flle only information.
1261 * This function returns whether the specified memcg contains any
1262 * reclaimable pages on a node. Returns true if there are any reclaimable
1263 * pages in the node.
1265 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1266 int nid
, bool noswap
)
1268 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1270 if (noswap
|| !total_swap_pages
)
1272 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1279 * Always updating the nodemask is not very good - even if we have an empty
1280 * list or the wrong list here, we can start from some node and traverse all
1281 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1284 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1288 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1289 * pagein/pageout changes since the last update.
1291 if (!atomic_read(&memcg
->numainfo_events
))
1293 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1296 /* make a nodemask where this memcg uses memory from */
1297 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1299 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1301 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1302 node_clear(nid
, memcg
->scan_nodes
);
1305 atomic_set(&memcg
->numainfo_events
, 0);
1306 atomic_set(&memcg
->numainfo_updating
, 0);
1310 * Selecting a node where we start reclaim from. Because what we need is just
1311 * reducing usage counter, start from anywhere is O,K. Considering
1312 * memory reclaim from current node, there are pros. and cons.
1314 * Freeing memory from current node means freeing memory from a node which
1315 * we'll use or we've used. So, it may make LRU bad. And if several threads
1316 * hit limits, it will see a contention on a node. But freeing from remote
1317 * node means more costs for memory reclaim because of memory latency.
1319 * Now, we use round-robin. Better algorithm is welcomed.
1321 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1325 mem_cgroup_may_update_nodemask(memcg
);
1326 node
= memcg
->last_scanned_node
;
1328 node
= next_node_in(node
, memcg
->scan_nodes
);
1330 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1331 * last time it really checked all the LRUs due to rate limiting.
1332 * Fallback to the current node in that case for simplicity.
1334 if (unlikely(node
== MAX_NUMNODES
))
1335 node
= numa_node_id();
1337 memcg
->last_scanned_node
= node
;
1341 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1347 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1350 unsigned long *total_scanned
)
1352 struct mem_cgroup
*victim
= NULL
;
1355 unsigned long excess
;
1356 unsigned long nr_scanned
;
1357 struct mem_cgroup_reclaim_cookie reclaim
= {
1362 excess
= soft_limit_excess(root_memcg
);
1365 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1370 * If we have not been able to reclaim
1371 * anything, it might because there are
1372 * no reclaimable pages under this hierarchy
1377 * We want to do more targeted reclaim.
1378 * excess >> 2 is not to excessive so as to
1379 * reclaim too much, nor too less that we keep
1380 * coming back to reclaim from this cgroup
1382 if (total
>= (excess
>> 2) ||
1383 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1388 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1389 pgdat
, &nr_scanned
);
1390 *total_scanned
+= nr_scanned
;
1391 if (!soft_limit_excess(root_memcg
))
1394 mem_cgroup_iter_break(root_memcg
, victim
);
1398 #ifdef CONFIG_LOCKDEP
1399 static struct lockdep_map memcg_oom_lock_dep_map
= {
1400 .name
= "memcg_oom_lock",
1404 static DEFINE_SPINLOCK(memcg_oom_lock
);
1407 * Check OOM-Killer is already running under our hierarchy.
1408 * If someone is running, return false.
1410 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1412 struct mem_cgroup
*iter
, *failed
= NULL
;
1414 spin_lock(&memcg_oom_lock
);
1416 for_each_mem_cgroup_tree(iter
, memcg
) {
1417 if (iter
->oom_lock
) {
1419 * this subtree of our hierarchy is already locked
1420 * so we cannot give a lock.
1423 mem_cgroup_iter_break(memcg
, iter
);
1426 iter
->oom_lock
= true;
1431 * OK, we failed to lock the whole subtree so we have
1432 * to clean up what we set up to the failing subtree
1434 for_each_mem_cgroup_tree(iter
, memcg
) {
1435 if (iter
== failed
) {
1436 mem_cgroup_iter_break(memcg
, iter
);
1439 iter
->oom_lock
= false;
1442 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1444 spin_unlock(&memcg_oom_lock
);
1449 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1451 struct mem_cgroup
*iter
;
1453 spin_lock(&memcg_oom_lock
);
1454 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
1455 for_each_mem_cgroup_tree(iter
, memcg
)
1456 iter
->oom_lock
= false;
1457 spin_unlock(&memcg_oom_lock
);
1460 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1462 struct mem_cgroup
*iter
;
1464 spin_lock(&memcg_oom_lock
);
1465 for_each_mem_cgroup_tree(iter
, memcg
)
1467 spin_unlock(&memcg_oom_lock
);
1470 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1472 struct mem_cgroup
*iter
;
1475 * When a new child is created while the hierarchy is under oom,
1476 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1478 spin_lock(&memcg_oom_lock
);
1479 for_each_mem_cgroup_tree(iter
, memcg
)
1480 if (iter
->under_oom
> 0)
1482 spin_unlock(&memcg_oom_lock
);
1485 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1487 struct oom_wait_info
{
1488 struct mem_cgroup
*memcg
;
1492 static int memcg_oom_wake_function(wait_queue_t
*wait
,
1493 unsigned mode
, int sync
, void *arg
)
1495 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1496 struct mem_cgroup
*oom_wait_memcg
;
1497 struct oom_wait_info
*oom_wait_info
;
1499 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1500 oom_wait_memcg
= oom_wait_info
->memcg
;
1502 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1503 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1505 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1508 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1511 * For the following lockless ->under_oom test, the only required
1512 * guarantee is that it must see the state asserted by an OOM when
1513 * this function is called as a result of userland actions
1514 * triggered by the notification of the OOM. This is trivially
1515 * achieved by invoking mem_cgroup_mark_under_oom() before
1516 * triggering notification.
1518 if (memcg
&& memcg
->under_oom
)
1519 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1522 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1524 if (!current
->memcg_may_oom
)
1527 * We are in the middle of the charge context here, so we
1528 * don't want to block when potentially sitting on a callstack
1529 * that holds all kinds of filesystem and mm locks.
1531 * Also, the caller may handle a failed allocation gracefully
1532 * (like optional page cache readahead) and so an OOM killer
1533 * invocation might not even be necessary.
1535 * That's why we don't do anything here except remember the
1536 * OOM context and then deal with it at the end of the page
1537 * fault when the stack is unwound, the locks are released,
1538 * and when we know whether the fault was overall successful.
1540 css_get(&memcg
->css
);
1541 current
->memcg_in_oom
= memcg
;
1542 current
->memcg_oom_gfp_mask
= mask
;
1543 current
->memcg_oom_order
= order
;
1547 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1548 * @handle: actually kill/wait or just clean up the OOM state
1550 * This has to be called at the end of a page fault if the memcg OOM
1551 * handler was enabled.
1553 * Memcg supports userspace OOM handling where failed allocations must
1554 * sleep on a waitqueue until the userspace task resolves the
1555 * situation. Sleeping directly in the charge context with all kinds
1556 * of locks held is not a good idea, instead we remember an OOM state
1557 * in the task and mem_cgroup_oom_synchronize() has to be called at
1558 * the end of the page fault to complete the OOM handling.
1560 * Returns %true if an ongoing memcg OOM situation was detected and
1561 * completed, %false otherwise.
1563 bool mem_cgroup_oom_synchronize(bool handle
)
1565 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1566 struct oom_wait_info owait
;
1569 /* OOM is global, do not handle */
1576 owait
.memcg
= memcg
;
1577 owait
.wait
.flags
= 0;
1578 owait
.wait
.func
= memcg_oom_wake_function
;
1579 owait
.wait
.private = current
;
1580 INIT_LIST_HEAD(&owait
.wait
.task_list
);
1582 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1583 mem_cgroup_mark_under_oom(memcg
);
1585 locked
= mem_cgroup_oom_trylock(memcg
);
1588 mem_cgroup_oom_notify(memcg
);
1590 if (locked
&& !memcg
->oom_kill_disable
) {
1591 mem_cgroup_unmark_under_oom(memcg
);
1592 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1593 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1594 current
->memcg_oom_order
);
1597 mem_cgroup_unmark_under_oom(memcg
);
1598 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1602 mem_cgroup_oom_unlock(memcg
);
1604 * There is no guarantee that an OOM-lock contender
1605 * sees the wakeups triggered by the OOM kill
1606 * uncharges. Wake any sleepers explicitely.
1608 memcg_oom_recover(memcg
);
1611 current
->memcg_in_oom
= NULL
;
1612 css_put(&memcg
->css
);
1617 * lock_page_memcg - lock a page->mem_cgroup binding
1620 * This function protects unlocked LRU pages from being moved to
1621 * another cgroup and stabilizes their page->mem_cgroup binding.
1623 void lock_page_memcg(struct page
*page
)
1625 struct mem_cgroup
*memcg
;
1626 unsigned long flags
;
1629 * The RCU lock is held throughout the transaction. The fast
1630 * path can get away without acquiring the memcg->move_lock
1631 * because page moving starts with an RCU grace period.
1635 if (mem_cgroup_disabled())
1638 memcg
= page
->mem_cgroup
;
1639 if (unlikely(!memcg
))
1642 if (atomic_read(&memcg
->moving_account
) <= 0)
1645 spin_lock_irqsave(&memcg
->move_lock
, flags
);
1646 if (memcg
!= page
->mem_cgroup
) {
1647 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1652 * When charge migration first begins, we can have locked and
1653 * unlocked page stat updates happening concurrently. Track
1654 * the task who has the lock for unlock_page_memcg().
1656 memcg
->move_lock_task
= current
;
1657 memcg
->move_lock_flags
= flags
;
1661 EXPORT_SYMBOL(lock_page_memcg
);
1664 * unlock_page_memcg - unlock a page->mem_cgroup binding
1667 void unlock_page_memcg(struct page
*page
)
1669 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
1671 if (memcg
&& memcg
->move_lock_task
== current
) {
1672 unsigned long flags
= memcg
->move_lock_flags
;
1674 memcg
->move_lock_task
= NULL
;
1675 memcg
->move_lock_flags
= 0;
1677 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1682 EXPORT_SYMBOL(unlock_page_memcg
);
1685 * size of first charge trial. "32" comes from vmscan.c's magic value.
1686 * TODO: maybe necessary to use big numbers in big irons.
1688 #define CHARGE_BATCH 32U
1689 struct memcg_stock_pcp
{
1690 struct mem_cgroup
*cached
; /* this never be root cgroup */
1691 unsigned int nr_pages
;
1692 struct work_struct work
;
1693 unsigned long flags
;
1694 #define FLUSHING_CACHED_CHARGE 0
1696 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
1697 static DEFINE_MUTEX(percpu_charge_mutex
);
1700 * consume_stock: Try to consume stocked charge on this cpu.
1701 * @memcg: memcg to consume from.
1702 * @nr_pages: how many pages to charge.
1704 * The charges will only happen if @memcg matches the current cpu's memcg
1705 * stock, and at least @nr_pages are available in that stock. Failure to
1706 * service an allocation will refill the stock.
1708 * returns true if successful, false otherwise.
1710 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1712 struct memcg_stock_pcp
*stock
;
1713 unsigned long flags
;
1716 if (nr_pages
> CHARGE_BATCH
)
1719 local_irq_save(flags
);
1721 stock
= this_cpu_ptr(&memcg_stock
);
1722 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
1723 stock
->nr_pages
-= nr_pages
;
1727 local_irq_restore(flags
);
1733 * Returns stocks cached in percpu and reset cached information.
1735 static void drain_stock(struct memcg_stock_pcp
*stock
)
1737 struct mem_cgroup
*old
= stock
->cached
;
1739 if (stock
->nr_pages
) {
1740 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
1741 if (do_memsw_account())
1742 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
1743 css_put_many(&old
->css
, stock
->nr_pages
);
1744 stock
->nr_pages
= 0;
1746 stock
->cached
= NULL
;
1749 static void drain_local_stock(struct work_struct
*dummy
)
1751 struct memcg_stock_pcp
*stock
;
1752 unsigned long flags
;
1754 local_irq_save(flags
);
1756 stock
= this_cpu_ptr(&memcg_stock
);
1758 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
1760 local_irq_restore(flags
);
1764 * Cache charges(val) to local per_cpu area.
1765 * This will be consumed by consume_stock() function, later.
1767 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1769 struct memcg_stock_pcp
*stock
;
1770 unsigned long flags
;
1772 local_irq_save(flags
);
1774 stock
= this_cpu_ptr(&memcg_stock
);
1775 if (stock
->cached
!= memcg
) { /* reset if necessary */
1777 stock
->cached
= memcg
;
1779 stock
->nr_pages
+= nr_pages
;
1781 local_irq_restore(flags
);
1785 * Drains all per-CPU charge caches for given root_memcg resp. subtree
1786 * of the hierarchy under it.
1788 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
1792 /* If someone's already draining, avoid adding running more workers. */
1793 if (!mutex_trylock(&percpu_charge_mutex
))
1795 /* Notify other cpus that system-wide "drain" is running */
1798 for_each_online_cpu(cpu
) {
1799 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
1800 struct mem_cgroup
*memcg
;
1802 memcg
= stock
->cached
;
1803 if (!memcg
|| !stock
->nr_pages
)
1805 if (!mem_cgroup_is_descendant(memcg
, root_memcg
))
1807 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
1809 drain_local_stock(&stock
->work
);
1811 schedule_work_on(cpu
, &stock
->work
);
1816 mutex_unlock(&percpu_charge_mutex
);
1819 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
1821 struct memcg_stock_pcp
*stock
;
1823 stock
= &per_cpu(memcg_stock
, cpu
);
1828 static void reclaim_high(struct mem_cgroup
*memcg
,
1829 unsigned int nr_pages
,
1833 if (page_counter_read(&memcg
->memory
) <= memcg
->high
)
1835 mem_cgroup_events(memcg
, MEMCG_HIGH
, 1);
1836 try_to_free_mem_cgroup_pages(memcg
, nr_pages
, gfp_mask
, true);
1837 } while ((memcg
= parent_mem_cgroup(memcg
)));
1840 static void high_work_func(struct work_struct
*work
)
1842 struct mem_cgroup
*memcg
;
1844 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
1845 reclaim_high(memcg
, CHARGE_BATCH
, GFP_KERNEL
);
1849 * Scheduled by try_charge() to be executed from the userland return path
1850 * and reclaims memory over the high limit.
1852 void mem_cgroup_handle_over_high(void)
1854 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
1855 struct mem_cgroup
*memcg
;
1857 if (likely(!nr_pages
))
1860 memcg
= get_mem_cgroup_from_mm(current
->mm
);
1861 reclaim_high(memcg
, nr_pages
, GFP_KERNEL
);
1862 css_put(&memcg
->css
);
1863 current
->memcg_nr_pages_over_high
= 0;
1866 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1867 unsigned int nr_pages
)
1869 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
1870 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
1871 struct mem_cgroup
*mem_over_limit
;
1872 struct page_counter
*counter
;
1873 unsigned long nr_reclaimed
;
1874 bool may_swap
= true;
1875 bool drained
= false;
1877 if (mem_cgroup_is_root(memcg
))
1880 if (consume_stock(memcg
, nr_pages
))
1883 if (!do_memsw_account() ||
1884 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
1885 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
1887 if (do_memsw_account())
1888 page_counter_uncharge(&memcg
->memsw
, batch
);
1889 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
1891 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
1895 if (batch
> nr_pages
) {
1901 * Unlike in global OOM situations, memcg is not in a physical
1902 * memory shortage. Allow dying and OOM-killed tasks to
1903 * bypass the last charges so that they can exit quickly and
1904 * free their memory.
1906 if (unlikely(test_thread_flag(TIF_MEMDIE
) ||
1907 fatal_signal_pending(current
) ||
1908 current
->flags
& PF_EXITING
))
1912 * Prevent unbounded recursion when reclaim operations need to
1913 * allocate memory. This might exceed the limits temporarily,
1914 * but we prefer facilitating memory reclaim and getting back
1915 * under the limit over triggering OOM kills in these cases.
1917 if (unlikely(current
->flags
& PF_MEMALLOC
))
1920 if (unlikely(task_in_memcg_oom(current
)))
1923 if (!gfpflags_allow_blocking(gfp_mask
))
1926 mem_cgroup_events(mem_over_limit
, MEMCG_MAX
, 1);
1928 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
1929 gfp_mask
, may_swap
);
1931 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
1935 drain_all_stock(mem_over_limit
);
1940 if (gfp_mask
& __GFP_NORETRY
)
1943 * Even though the limit is exceeded at this point, reclaim
1944 * may have been able to free some pages. Retry the charge
1945 * before killing the task.
1947 * Only for regular pages, though: huge pages are rather
1948 * unlikely to succeed so close to the limit, and we fall back
1949 * to regular pages anyway in case of failure.
1951 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
1954 * At task move, charge accounts can be doubly counted. So, it's
1955 * better to wait until the end of task_move if something is going on.
1957 if (mem_cgroup_wait_acct_move(mem_over_limit
))
1963 if (gfp_mask
& __GFP_NOFAIL
)
1966 if (fatal_signal_pending(current
))
1969 mem_cgroup_events(mem_over_limit
, MEMCG_OOM
, 1);
1971 mem_cgroup_oom(mem_over_limit
, gfp_mask
,
1972 get_order(nr_pages
* PAGE_SIZE
));
1974 if (!(gfp_mask
& __GFP_NOFAIL
))
1978 * The allocation either can't fail or will lead to more memory
1979 * being freed very soon. Allow memory usage go over the limit
1980 * temporarily by force charging it.
1982 page_counter_charge(&memcg
->memory
, nr_pages
);
1983 if (do_memsw_account())
1984 page_counter_charge(&memcg
->memsw
, nr_pages
);
1985 css_get_many(&memcg
->css
, nr_pages
);
1990 css_get_many(&memcg
->css
, batch
);
1991 if (batch
> nr_pages
)
1992 refill_stock(memcg
, batch
- nr_pages
);
1995 * If the hierarchy is above the normal consumption range, schedule
1996 * reclaim on returning to userland. We can perform reclaim here
1997 * if __GFP_RECLAIM but let's always punt for simplicity and so that
1998 * GFP_KERNEL can consistently be used during reclaim. @memcg is
1999 * not recorded as it most likely matches current's and won't
2000 * change in the meantime. As high limit is checked again before
2001 * reclaim, the cost of mismatch is negligible.
2004 if (page_counter_read(&memcg
->memory
) > memcg
->high
) {
2005 /* Don't bother a random interrupted task */
2006 if (in_interrupt()) {
2007 schedule_work(&memcg
->high_work
);
2010 current
->memcg_nr_pages_over_high
+= batch
;
2011 set_notify_resume(current
);
2014 } while ((memcg
= parent_mem_cgroup(memcg
)));
2019 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2021 if (mem_cgroup_is_root(memcg
))
2024 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2025 if (do_memsw_account())
2026 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2028 css_put_many(&memcg
->css
, nr_pages
);
2031 static void lock_page_lru(struct page
*page
, int *isolated
)
2033 struct zone
*zone
= page_zone(page
);
2035 spin_lock_irq(zone_lru_lock(zone
));
2036 if (PageLRU(page
)) {
2037 struct lruvec
*lruvec
;
2039 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2041 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2047 static void unlock_page_lru(struct page
*page
, int isolated
)
2049 struct zone
*zone
= page_zone(page
);
2052 struct lruvec
*lruvec
;
2054 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2055 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2057 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2059 spin_unlock_irq(zone_lru_lock(zone
));
2062 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2067 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2070 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2071 * may already be on some other mem_cgroup's LRU. Take care of it.
2074 lock_page_lru(page
, &isolated
);
2077 * Nobody should be changing or seriously looking at
2078 * page->mem_cgroup at this point:
2080 * - the page is uncharged
2082 * - the page is off-LRU
2084 * - an anonymous fault has exclusive page access, except for
2085 * a locked page table
2087 * - a page cache insertion, a swapin fault, or a migration
2088 * have the page locked
2090 page
->mem_cgroup
= memcg
;
2093 unlock_page_lru(page
, isolated
);
2097 static int memcg_alloc_cache_id(void)
2102 id
= ida_simple_get(&memcg_cache_ida
,
2103 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2107 if (id
< memcg_nr_cache_ids
)
2111 * There's no space for the new id in memcg_caches arrays,
2112 * so we have to grow them.
2114 down_write(&memcg_cache_ids_sem
);
2116 size
= 2 * (id
+ 1);
2117 if (size
< MEMCG_CACHES_MIN_SIZE
)
2118 size
= MEMCG_CACHES_MIN_SIZE
;
2119 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2120 size
= MEMCG_CACHES_MAX_SIZE
;
2122 err
= memcg_update_all_caches(size
);
2124 err
= memcg_update_all_list_lrus(size
);
2126 memcg_nr_cache_ids
= size
;
2128 up_write(&memcg_cache_ids_sem
);
2131 ida_simple_remove(&memcg_cache_ida
, id
);
2137 static void memcg_free_cache_id(int id
)
2139 ida_simple_remove(&memcg_cache_ida
, id
);
2142 struct memcg_kmem_cache_create_work
{
2143 struct mem_cgroup
*memcg
;
2144 struct kmem_cache
*cachep
;
2145 struct work_struct work
;
2148 static void memcg_kmem_cache_create_func(struct work_struct
*w
)
2150 struct memcg_kmem_cache_create_work
*cw
=
2151 container_of(w
, struct memcg_kmem_cache_create_work
, work
);
2152 struct mem_cgroup
*memcg
= cw
->memcg
;
2153 struct kmem_cache
*cachep
= cw
->cachep
;
2155 memcg_create_kmem_cache(memcg
, cachep
);
2157 css_put(&memcg
->css
);
2162 * Enqueue the creation of a per-memcg kmem_cache.
2164 static void __memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2165 struct kmem_cache
*cachep
)
2167 struct memcg_kmem_cache_create_work
*cw
;
2169 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
);
2173 css_get(&memcg
->css
);
2176 cw
->cachep
= cachep
;
2177 INIT_WORK(&cw
->work
, memcg_kmem_cache_create_func
);
2179 queue_work(memcg_kmem_cache_wq
, &cw
->work
);
2182 static void memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2183 struct kmem_cache
*cachep
)
2186 * We need to stop accounting when we kmalloc, because if the
2187 * corresponding kmalloc cache is not yet created, the first allocation
2188 * in __memcg_schedule_kmem_cache_create will recurse.
2190 * However, it is better to enclose the whole function. Depending on
2191 * the debugging options enabled, INIT_WORK(), for instance, can
2192 * trigger an allocation. This too, will make us recurse. Because at
2193 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2194 * the safest choice is to do it like this, wrapping the whole function.
2196 current
->memcg_kmem_skip_account
= 1;
2197 __memcg_schedule_kmem_cache_create(memcg
, cachep
);
2198 current
->memcg_kmem_skip_account
= 0;
2201 static inline bool memcg_kmem_bypass(void)
2203 if (in_interrupt() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
2209 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2210 * @cachep: the original global kmem cache
2212 * Return the kmem_cache we're supposed to use for a slab allocation.
2213 * We try to use the current memcg's version of the cache.
2215 * If the cache does not exist yet, if we are the first user of it, we
2216 * create it asynchronously in a workqueue and let the current allocation
2217 * go through with the original cache.
2219 * This function takes a reference to the cache it returns to assure it
2220 * won't get destroyed while we are working with it. Once the caller is
2221 * done with it, memcg_kmem_put_cache() must be called to release the
2224 struct kmem_cache
*memcg_kmem_get_cache(struct kmem_cache
*cachep
)
2226 struct mem_cgroup
*memcg
;
2227 struct kmem_cache
*memcg_cachep
;
2230 VM_BUG_ON(!is_root_cache(cachep
));
2232 if (memcg_kmem_bypass())
2235 if (current
->memcg_kmem_skip_account
)
2238 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2239 kmemcg_id
= READ_ONCE(memcg
->kmemcg_id
);
2243 memcg_cachep
= cache_from_memcg_idx(cachep
, kmemcg_id
);
2244 if (likely(memcg_cachep
))
2245 return memcg_cachep
;
2248 * If we are in a safe context (can wait, and not in interrupt
2249 * context), we could be be predictable and return right away.
2250 * This would guarantee that the allocation being performed
2251 * already belongs in the new cache.
2253 * However, there are some clashes that can arrive from locking.
2254 * For instance, because we acquire the slab_mutex while doing
2255 * memcg_create_kmem_cache, this means no further allocation
2256 * could happen with the slab_mutex held. So it's better to
2259 memcg_schedule_kmem_cache_create(memcg
, cachep
);
2261 css_put(&memcg
->css
);
2266 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2267 * @cachep: the cache returned by memcg_kmem_get_cache
2269 void memcg_kmem_put_cache(struct kmem_cache
*cachep
)
2271 if (!is_root_cache(cachep
))
2272 css_put(&cachep
->memcg_params
.memcg
->css
);
2276 * memcg_kmem_charge: charge a kmem page
2277 * @page: page to charge
2278 * @gfp: reclaim mode
2279 * @order: allocation order
2280 * @memcg: memory cgroup to charge
2282 * Returns 0 on success, an error code on failure.
2284 int memcg_kmem_charge_memcg(struct page
*page
, gfp_t gfp
, int order
,
2285 struct mem_cgroup
*memcg
)
2287 unsigned int nr_pages
= 1 << order
;
2288 struct page_counter
*counter
;
2291 ret
= try_charge(memcg
, gfp
, nr_pages
);
2295 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2296 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2297 cancel_charge(memcg
, nr_pages
);
2301 page
->mem_cgroup
= memcg
;
2307 * memcg_kmem_charge: charge a kmem page to the current memory cgroup
2308 * @page: page to charge
2309 * @gfp: reclaim mode
2310 * @order: allocation order
2312 * Returns 0 on success, an error code on failure.
2314 int memcg_kmem_charge(struct page
*page
, gfp_t gfp
, int order
)
2316 struct mem_cgroup
*memcg
;
2319 if (memcg_kmem_bypass())
2322 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2323 if (!mem_cgroup_is_root(memcg
)) {
2324 ret
= memcg_kmem_charge_memcg(page
, gfp
, order
, memcg
);
2326 __SetPageKmemcg(page
);
2328 css_put(&memcg
->css
);
2332 * memcg_kmem_uncharge: uncharge a kmem page
2333 * @page: page to uncharge
2334 * @order: allocation order
2336 void memcg_kmem_uncharge(struct page
*page
, int order
)
2338 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
2339 unsigned int nr_pages
= 1 << order
;
2344 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
2346 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2347 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2349 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2350 if (do_memsw_account())
2351 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2353 page
->mem_cgroup
= NULL
;
2355 /* slab pages do not have PageKmemcg flag set */
2356 if (PageKmemcg(page
))
2357 __ClearPageKmemcg(page
);
2359 css_put_many(&memcg
->css
, nr_pages
);
2361 #endif /* !CONFIG_SLOB */
2363 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2366 * Because tail pages are not marked as "used", set it. We're under
2367 * zone_lru_lock and migration entries setup in all page mappings.
2369 void mem_cgroup_split_huge_fixup(struct page
*head
)
2373 if (mem_cgroup_disabled())
2376 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
2377 head
[i
].mem_cgroup
= head
->mem_cgroup
;
2379 __this_cpu_sub(head
->mem_cgroup
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
2382 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2384 #ifdef CONFIG_MEMCG_SWAP
2385 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
2388 int val
= (charge
) ? 1 : -1;
2389 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
2393 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2394 * @entry: swap entry to be moved
2395 * @from: mem_cgroup which the entry is moved from
2396 * @to: mem_cgroup which the entry is moved to
2398 * It succeeds only when the swap_cgroup's record for this entry is the same
2399 * as the mem_cgroup's id of @from.
2401 * Returns 0 on success, -EINVAL on failure.
2403 * The caller must have charged to @to, IOW, called page_counter_charge() about
2404 * both res and memsw, and called css_get().
2406 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
2407 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2409 unsigned short old_id
, new_id
;
2411 old_id
= mem_cgroup_id(from
);
2412 new_id
= mem_cgroup_id(to
);
2414 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
2415 mem_cgroup_swap_statistics(from
, false);
2416 mem_cgroup_swap_statistics(to
, true);
2422 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
2423 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2429 static DEFINE_MUTEX(memcg_limit_mutex
);
2431 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
2432 unsigned long limit
)
2434 unsigned long curusage
;
2435 unsigned long oldusage
;
2436 bool enlarge
= false;
2441 * For keeping hierarchical_reclaim simple, how long we should retry
2442 * is depends on callers. We set our retry-count to be function
2443 * of # of children which we should visit in this loop.
2445 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2446 mem_cgroup_count_children(memcg
);
2448 oldusage
= page_counter_read(&memcg
->memory
);
2451 if (signal_pending(current
)) {
2456 mutex_lock(&memcg_limit_mutex
);
2457 if (limit
> memcg
->memsw
.limit
) {
2458 mutex_unlock(&memcg_limit_mutex
);
2462 if (limit
> memcg
->memory
.limit
)
2464 ret
= page_counter_limit(&memcg
->memory
, limit
);
2465 mutex_unlock(&memcg_limit_mutex
);
2470 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, true);
2472 curusage
= page_counter_read(&memcg
->memory
);
2473 /* Usage is reduced ? */
2474 if (curusage
>= oldusage
)
2477 oldusage
= curusage
;
2478 } while (retry_count
);
2480 if (!ret
&& enlarge
)
2481 memcg_oom_recover(memcg
);
2486 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
2487 unsigned long limit
)
2489 unsigned long curusage
;
2490 unsigned long oldusage
;
2491 bool enlarge
= false;
2495 /* see mem_cgroup_resize_res_limit */
2496 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2497 mem_cgroup_count_children(memcg
);
2499 oldusage
= page_counter_read(&memcg
->memsw
);
2502 if (signal_pending(current
)) {
2507 mutex_lock(&memcg_limit_mutex
);
2508 if (limit
< memcg
->memory
.limit
) {
2509 mutex_unlock(&memcg_limit_mutex
);
2513 if (limit
> memcg
->memsw
.limit
)
2515 ret
= page_counter_limit(&memcg
->memsw
, limit
);
2516 mutex_unlock(&memcg_limit_mutex
);
2521 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, false);
2523 curusage
= page_counter_read(&memcg
->memsw
);
2524 /* Usage is reduced ? */
2525 if (curusage
>= oldusage
)
2528 oldusage
= curusage
;
2529 } while (retry_count
);
2531 if (!ret
&& enlarge
)
2532 memcg_oom_recover(memcg
);
2537 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
2539 unsigned long *total_scanned
)
2541 unsigned long nr_reclaimed
= 0;
2542 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
2543 unsigned long reclaimed
;
2545 struct mem_cgroup_tree_per_node
*mctz
;
2546 unsigned long excess
;
2547 unsigned long nr_scanned
;
2552 mctz
= soft_limit_tree_node(pgdat
->node_id
);
2555 * Do not even bother to check the largest node if the root
2556 * is empty. Do it lockless to prevent lock bouncing. Races
2557 * are acceptable as soft limit is best effort anyway.
2559 if (RB_EMPTY_ROOT(&mctz
->rb_root
))
2563 * This loop can run a while, specially if mem_cgroup's continuously
2564 * keep exceeding their soft limit and putting the system under
2571 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
2576 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
2577 gfp_mask
, &nr_scanned
);
2578 nr_reclaimed
+= reclaimed
;
2579 *total_scanned
+= nr_scanned
;
2580 spin_lock_irq(&mctz
->lock
);
2581 __mem_cgroup_remove_exceeded(mz
, mctz
);
2584 * If we failed to reclaim anything from this memory cgroup
2585 * it is time to move on to the next cgroup
2589 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
2591 excess
= soft_limit_excess(mz
->memcg
);
2593 * One school of thought says that we should not add
2594 * back the node to the tree if reclaim returns 0.
2595 * But our reclaim could return 0, simply because due
2596 * to priority we are exposing a smaller subset of
2597 * memory to reclaim from. Consider this as a longer
2600 /* If excess == 0, no tree ops */
2601 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
2602 spin_unlock_irq(&mctz
->lock
);
2603 css_put(&mz
->memcg
->css
);
2606 * Could not reclaim anything and there are no more
2607 * mem cgroups to try or we seem to be looping without
2608 * reclaiming anything.
2610 if (!nr_reclaimed
&&
2612 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
2614 } while (!nr_reclaimed
);
2616 css_put(&next_mz
->memcg
->css
);
2617 return nr_reclaimed
;
2621 * Test whether @memcg has children, dead or alive. Note that this
2622 * function doesn't care whether @memcg has use_hierarchy enabled and
2623 * returns %true if there are child csses according to the cgroup
2624 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
2626 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
2631 ret
= css_next_child(NULL
, &memcg
->css
);
2637 * Reclaims as many pages from the given memcg as possible.
2639 * Caller is responsible for holding css reference for memcg.
2641 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
2643 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2645 /* we call try-to-free pages for make this cgroup empty */
2646 lru_add_drain_all();
2647 /* try to free all pages in this cgroup */
2648 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
2651 if (signal_pending(current
))
2654 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
2658 /* maybe some writeback is necessary */
2659 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
2667 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
2668 char *buf
, size_t nbytes
,
2671 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2673 if (mem_cgroup_is_root(memcg
))
2675 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
2678 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
2681 return mem_cgroup_from_css(css
)->use_hierarchy
;
2684 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
2685 struct cftype
*cft
, u64 val
)
2688 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2689 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
2691 if (memcg
->use_hierarchy
== val
)
2695 * If parent's use_hierarchy is set, we can't make any modifications
2696 * in the child subtrees. If it is unset, then the change can
2697 * occur, provided the current cgroup has no children.
2699 * For the root cgroup, parent_mem is NULL, we allow value to be
2700 * set if there are no children.
2702 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
2703 (val
== 1 || val
== 0)) {
2704 if (!memcg_has_children(memcg
))
2705 memcg
->use_hierarchy
= val
;
2714 static void tree_stat(struct mem_cgroup
*memcg
, unsigned long *stat
)
2716 struct mem_cgroup
*iter
;
2719 memset(stat
, 0, sizeof(*stat
) * MEMCG_NR_STAT
);
2721 for_each_mem_cgroup_tree(iter
, memcg
) {
2722 for (i
= 0; i
< MEMCG_NR_STAT
; i
++)
2723 stat
[i
] += mem_cgroup_read_stat(iter
, i
);
2727 static void tree_events(struct mem_cgroup
*memcg
, unsigned long *events
)
2729 struct mem_cgroup
*iter
;
2732 memset(events
, 0, sizeof(*events
) * MEMCG_NR_EVENTS
);
2734 for_each_mem_cgroup_tree(iter
, memcg
) {
2735 for (i
= 0; i
< MEMCG_NR_EVENTS
; i
++)
2736 events
[i
] += mem_cgroup_read_events(iter
, i
);
2740 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
2742 unsigned long val
= 0;
2744 if (mem_cgroup_is_root(memcg
)) {
2745 struct mem_cgroup
*iter
;
2747 for_each_mem_cgroup_tree(iter
, memcg
) {
2748 val
+= mem_cgroup_read_stat(iter
,
2749 MEM_CGROUP_STAT_CACHE
);
2750 val
+= mem_cgroup_read_stat(iter
,
2751 MEM_CGROUP_STAT_RSS
);
2753 val
+= mem_cgroup_read_stat(iter
,
2754 MEM_CGROUP_STAT_SWAP
);
2758 val
= page_counter_read(&memcg
->memory
);
2760 val
= page_counter_read(&memcg
->memsw
);
2773 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
2776 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2777 struct page_counter
*counter
;
2779 switch (MEMFILE_TYPE(cft
->private)) {
2781 counter
= &memcg
->memory
;
2784 counter
= &memcg
->memsw
;
2787 counter
= &memcg
->kmem
;
2790 counter
= &memcg
->tcpmem
;
2796 switch (MEMFILE_ATTR(cft
->private)) {
2798 if (counter
== &memcg
->memory
)
2799 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
2800 if (counter
== &memcg
->memsw
)
2801 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
2802 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
2804 return (u64
)counter
->limit
* PAGE_SIZE
;
2806 return (u64
)counter
->watermark
* PAGE_SIZE
;
2808 return counter
->failcnt
;
2809 case RES_SOFT_LIMIT
:
2810 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
2817 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2821 if (cgroup_memory_nokmem
)
2824 BUG_ON(memcg
->kmemcg_id
>= 0);
2825 BUG_ON(memcg
->kmem_state
);
2827 memcg_id
= memcg_alloc_cache_id();
2831 static_branch_inc(&memcg_kmem_enabled_key
);
2833 * A memory cgroup is considered kmem-online as soon as it gets
2834 * kmemcg_id. Setting the id after enabling static branching will
2835 * guarantee no one starts accounting before all call sites are
2838 memcg
->kmemcg_id
= memcg_id
;
2839 memcg
->kmem_state
= KMEM_ONLINE
;
2840 INIT_LIST_HEAD(&memcg
->kmem_caches
);
2845 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2847 struct cgroup_subsys_state
*css
;
2848 struct mem_cgroup
*parent
, *child
;
2851 if (memcg
->kmem_state
!= KMEM_ONLINE
)
2854 * Clear the online state before clearing memcg_caches array
2855 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
2856 * guarantees that no cache will be created for this cgroup
2857 * after we are done (see memcg_create_kmem_cache()).
2859 memcg
->kmem_state
= KMEM_ALLOCATED
;
2861 memcg_deactivate_kmem_caches(memcg
);
2863 kmemcg_id
= memcg
->kmemcg_id
;
2864 BUG_ON(kmemcg_id
< 0);
2866 parent
= parent_mem_cgroup(memcg
);
2868 parent
= root_mem_cgroup
;
2871 * Change kmemcg_id of this cgroup and all its descendants to the
2872 * parent's id, and then move all entries from this cgroup's list_lrus
2873 * to ones of the parent. After we have finished, all list_lrus
2874 * corresponding to this cgroup are guaranteed to remain empty. The
2875 * ordering is imposed by list_lru_node->lock taken by
2876 * memcg_drain_all_list_lrus().
2878 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
2879 css_for_each_descendant_pre(css
, &memcg
->css
) {
2880 child
= mem_cgroup_from_css(css
);
2881 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
2882 child
->kmemcg_id
= parent
->kmemcg_id
;
2883 if (!memcg
->use_hierarchy
)
2888 memcg_drain_all_list_lrus(kmemcg_id
, parent
->kmemcg_id
);
2890 memcg_free_cache_id(kmemcg_id
);
2893 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2895 /* css_alloc() failed, offlining didn't happen */
2896 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
2897 memcg_offline_kmem(memcg
);
2899 if (memcg
->kmem_state
== KMEM_ALLOCATED
) {
2900 memcg_destroy_kmem_caches(memcg
);
2901 static_branch_dec(&memcg_kmem_enabled_key
);
2902 WARN_ON(page_counter_read(&memcg
->kmem
));
2906 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2910 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2913 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2916 #endif /* !CONFIG_SLOB */
2918 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
2919 unsigned long limit
)
2923 mutex_lock(&memcg_limit_mutex
);
2924 ret
= page_counter_limit(&memcg
->kmem
, limit
);
2925 mutex_unlock(&memcg_limit_mutex
);
2929 static int memcg_update_tcp_limit(struct mem_cgroup
*memcg
, unsigned long limit
)
2933 mutex_lock(&memcg_limit_mutex
);
2935 ret
= page_counter_limit(&memcg
->tcpmem
, limit
);
2939 if (!memcg
->tcpmem_active
) {
2941 * The active flag needs to be written after the static_key
2942 * update. This is what guarantees that the socket activation
2943 * function is the last one to run. See mem_cgroup_sk_alloc()
2944 * for details, and note that we don't mark any socket as
2945 * belonging to this memcg until that flag is up.
2947 * We need to do this, because static_keys will span multiple
2948 * sites, but we can't control their order. If we mark a socket
2949 * as accounted, but the accounting functions are not patched in
2950 * yet, we'll lose accounting.
2952 * We never race with the readers in mem_cgroup_sk_alloc(),
2953 * because when this value change, the code to process it is not
2956 static_branch_inc(&memcg_sockets_enabled_key
);
2957 memcg
->tcpmem_active
= true;
2960 mutex_unlock(&memcg_limit_mutex
);
2965 * The user of this function is...
2968 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
2969 char *buf
, size_t nbytes
, loff_t off
)
2971 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2972 unsigned long nr_pages
;
2975 buf
= strstrip(buf
);
2976 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
2980 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
2982 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
2986 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
2988 ret
= mem_cgroup_resize_limit(memcg
, nr_pages
);
2991 ret
= mem_cgroup_resize_memsw_limit(memcg
, nr_pages
);
2994 ret
= memcg_update_kmem_limit(memcg
, nr_pages
);
2997 ret
= memcg_update_tcp_limit(memcg
, nr_pages
);
3001 case RES_SOFT_LIMIT
:
3002 memcg
->soft_limit
= nr_pages
;
3006 return ret
?: nbytes
;
3009 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3010 size_t nbytes
, loff_t off
)
3012 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3013 struct page_counter
*counter
;
3015 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3017 counter
= &memcg
->memory
;
3020 counter
= &memcg
->memsw
;
3023 counter
= &memcg
->kmem
;
3026 counter
= &memcg
->tcpmem
;
3032 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3034 page_counter_reset_watermark(counter
);
3037 counter
->failcnt
= 0;
3046 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3049 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3053 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3054 struct cftype
*cft
, u64 val
)
3056 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3058 if (val
& ~MOVE_MASK
)
3062 * No kind of locking is needed in here, because ->can_attach() will
3063 * check this value once in the beginning of the process, and then carry
3064 * on with stale data. This means that changes to this value will only
3065 * affect task migrations starting after the change.
3067 memcg
->move_charge_at_immigrate
= val
;
3071 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3072 struct cftype
*cft
, u64 val
)
3079 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3083 unsigned int lru_mask
;
3086 static const struct numa_stat stats
[] = {
3087 { "total", LRU_ALL
},
3088 { "file", LRU_ALL_FILE
},
3089 { "anon", LRU_ALL_ANON
},
3090 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3092 const struct numa_stat
*stat
;
3095 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3097 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3098 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
3099 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
3100 for_each_node_state(nid
, N_MEMORY
) {
3101 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3103 seq_printf(m
, " N%d=%lu", nid
, nr
);
3108 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3109 struct mem_cgroup
*iter
;
3112 for_each_mem_cgroup_tree(iter
, memcg
)
3113 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
3114 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
3115 for_each_node_state(nid
, N_MEMORY
) {
3117 for_each_mem_cgroup_tree(iter
, memcg
)
3118 nr
+= mem_cgroup_node_nr_lru_pages(
3119 iter
, nid
, stat
->lru_mask
);
3120 seq_printf(m
, " N%d=%lu", nid
, nr
);
3127 #endif /* CONFIG_NUMA */
3129 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3131 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3132 unsigned long memory
, memsw
;
3133 struct mem_cgroup
*mi
;
3136 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_stat_names
) !=
3137 MEM_CGROUP_STAT_NSTATS
);
3138 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_events_names
) !=
3139 MEM_CGROUP_EVENTS_NSTATS
);
3140 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
3142 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3143 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_memsw_account())
3145 seq_printf(m
, "%s %lu\n", mem_cgroup_stat_names
[i
],
3146 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
3149 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
3150 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
3151 mem_cgroup_read_events(memcg
, i
));
3153 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3154 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
3155 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
3157 /* Hierarchical information */
3158 memory
= memsw
= PAGE_COUNTER_MAX
;
3159 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3160 memory
= min(memory
, mi
->memory
.limit
);
3161 memsw
= min(memsw
, mi
->memsw
.limit
);
3163 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3164 (u64
)memory
* PAGE_SIZE
);
3165 if (do_memsw_account())
3166 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3167 (u64
)memsw
* PAGE_SIZE
);
3169 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3170 unsigned long long val
= 0;
3172 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_memsw_account())
3174 for_each_mem_cgroup_tree(mi
, memcg
)
3175 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
3176 seq_printf(m
, "total_%s %llu\n", mem_cgroup_stat_names
[i
], val
);
3179 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
3180 unsigned long long val
= 0;
3182 for_each_mem_cgroup_tree(mi
, memcg
)
3183 val
+= mem_cgroup_read_events(mi
, i
);
3184 seq_printf(m
, "total_%s %llu\n",
3185 mem_cgroup_events_names
[i
], val
);
3188 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
3189 unsigned long long val
= 0;
3191 for_each_mem_cgroup_tree(mi
, memcg
)
3192 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
3193 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
3196 #ifdef CONFIG_DEBUG_VM
3199 struct mem_cgroup_per_node
*mz
;
3200 struct zone_reclaim_stat
*rstat
;
3201 unsigned long recent_rotated
[2] = {0, 0};
3202 unsigned long recent_scanned
[2] = {0, 0};
3204 for_each_online_pgdat(pgdat
) {
3205 mz
= mem_cgroup_nodeinfo(memcg
, pgdat
->node_id
);
3206 rstat
= &mz
->lruvec
.reclaim_stat
;
3208 recent_rotated
[0] += rstat
->recent_rotated
[0];
3209 recent_rotated
[1] += rstat
->recent_rotated
[1];
3210 recent_scanned
[0] += rstat
->recent_scanned
[0];
3211 recent_scanned
[1] += rstat
->recent_scanned
[1];
3213 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
3214 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
3215 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
3216 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
3223 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3226 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3228 return mem_cgroup_swappiness(memcg
);
3231 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3232 struct cftype
*cft
, u64 val
)
3234 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3240 memcg
->swappiness
= val
;
3242 vm_swappiness
= val
;
3247 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3249 struct mem_cgroup_threshold_ary
*t
;
3250 unsigned long usage
;
3255 t
= rcu_dereference(memcg
->thresholds
.primary
);
3257 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3262 usage
= mem_cgroup_usage(memcg
, swap
);
3265 * current_threshold points to threshold just below or equal to usage.
3266 * If it's not true, a threshold was crossed after last
3267 * call of __mem_cgroup_threshold().
3269 i
= t
->current_threshold
;
3272 * Iterate backward over array of thresholds starting from
3273 * current_threshold and check if a threshold is crossed.
3274 * If none of thresholds below usage is crossed, we read
3275 * only one element of the array here.
3277 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3278 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3280 /* i = current_threshold + 1 */
3284 * Iterate forward over array of thresholds starting from
3285 * current_threshold+1 and check if a threshold is crossed.
3286 * If none of thresholds above usage is crossed, we read
3287 * only one element of the array here.
3289 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
3290 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3292 /* Update current_threshold */
3293 t
->current_threshold
= i
- 1;
3298 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
3301 __mem_cgroup_threshold(memcg
, false);
3302 if (do_memsw_account())
3303 __mem_cgroup_threshold(memcg
, true);
3305 memcg
= parent_mem_cgroup(memcg
);
3309 static int compare_thresholds(const void *a
, const void *b
)
3311 const struct mem_cgroup_threshold
*_a
= a
;
3312 const struct mem_cgroup_threshold
*_b
= b
;
3314 if (_a
->threshold
> _b
->threshold
)
3317 if (_a
->threshold
< _b
->threshold
)
3323 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
3325 struct mem_cgroup_eventfd_list
*ev
;
3327 spin_lock(&memcg_oom_lock
);
3329 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
3330 eventfd_signal(ev
->eventfd
, 1);
3332 spin_unlock(&memcg_oom_lock
);
3336 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
3338 struct mem_cgroup
*iter
;
3340 for_each_mem_cgroup_tree(iter
, memcg
)
3341 mem_cgroup_oom_notify_cb(iter
);
3344 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3345 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
3347 struct mem_cgroup_thresholds
*thresholds
;
3348 struct mem_cgroup_threshold_ary
*new;
3349 unsigned long threshold
;
3350 unsigned long usage
;
3353 ret
= page_counter_memparse(args
, "-1", &threshold
);
3357 mutex_lock(&memcg
->thresholds_lock
);
3360 thresholds
= &memcg
->thresholds
;
3361 usage
= mem_cgroup_usage(memcg
, false);
3362 } else if (type
== _MEMSWAP
) {
3363 thresholds
= &memcg
->memsw_thresholds
;
3364 usage
= mem_cgroup_usage(memcg
, true);
3368 /* Check if a threshold crossed before adding a new one */
3369 if (thresholds
->primary
)
3370 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3372 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
3374 /* Allocate memory for new array of thresholds */
3375 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
3383 /* Copy thresholds (if any) to new array */
3384 if (thresholds
->primary
) {
3385 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
3386 sizeof(struct mem_cgroup_threshold
));
3389 /* Add new threshold */
3390 new->entries
[size
- 1].eventfd
= eventfd
;
3391 new->entries
[size
- 1].threshold
= threshold
;
3393 /* Sort thresholds. Registering of new threshold isn't time-critical */
3394 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
3395 compare_thresholds
, NULL
);
3397 /* Find current threshold */
3398 new->current_threshold
= -1;
3399 for (i
= 0; i
< size
; i
++) {
3400 if (new->entries
[i
].threshold
<= usage
) {
3402 * new->current_threshold will not be used until
3403 * rcu_assign_pointer(), so it's safe to increment
3406 ++new->current_threshold
;
3411 /* Free old spare buffer and save old primary buffer as spare */
3412 kfree(thresholds
->spare
);
3413 thresholds
->spare
= thresholds
->primary
;
3415 rcu_assign_pointer(thresholds
->primary
, new);
3417 /* To be sure that nobody uses thresholds */
3421 mutex_unlock(&memcg
->thresholds_lock
);
3426 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3427 struct eventfd_ctx
*eventfd
, const char *args
)
3429 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
3432 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3433 struct eventfd_ctx
*eventfd
, const char *args
)
3435 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
3438 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3439 struct eventfd_ctx
*eventfd
, enum res_type type
)
3441 struct mem_cgroup_thresholds
*thresholds
;
3442 struct mem_cgroup_threshold_ary
*new;
3443 unsigned long usage
;
3446 mutex_lock(&memcg
->thresholds_lock
);
3449 thresholds
= &memcg
->thresholds
;
3450 usage
= mem_cgroup_usage(memcg
, false);
3451 } else if (type
== _MEMSWAP
) {
3452 thresholds
= &memcg
->memsw_thresholds
;
3453 usage
= mem_cgroup_usage(memcg
, true);
3457 if (!thresholds
->primary
)
3460 /* Check if a threshold crossed before removing */
3461 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3463 /* Calculate new number of threshold */
3465 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
3466 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
3470 new = thresholds
->spare
;
3472 /* Set thresholds array to NULL if we don't have thresholds */
3481 /* Copy thresholds and find current threshold */
3482 new->current_threshold
= -1;
3483 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
3484 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
3487 new->entries
[j
] = thresholds
->primary
->entries
[i
];
3488 if (new->entries
[j
].threshold
<= usage
) {
3490 * new->current_threshold will not be used
3491 * until rcu_assign_pointer(), so it's safe to increment
3494 ++new->current_threshold
;
3500 /* Swap primary and spare array */
3501 thresholds
->spare
= thresholds
->primary
;
3503 rcu_assign_pointer(thresholds
->primary
, new);
3505 /* To be sure that nobody uses thresholds */
3508 /* If all events are unregistered, free the spare array */
3510 kfree(thresholds
->spare
);
3511 thresholds
->spare
= NULL
;
3514 mutex_unlock(&memcg
->thresholds_lock
);
3517 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3518 struct eventfd_ctx
*eventfd
)
3520 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
3523 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3524 struct eventfd_ctx
*eventfd
)
3526 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
3529 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
3530 struct eventfd_ctx
*eventfd
, const char *args
)
3532 struct mem_cgroup_eventfd_list
*event
;
3534 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
3538 spin_lock(&memcg_oom_lock
);
3540 event
->eventfd
= eventfd
;
3541 list_add(&event
->list
, &memcg
->oom_notify
);
3543 /* already in OOM ? */
3544 if (memcg
->under_oom
)
3545 eventfd_signal(eventfd
, 1);
3546 spin_unlock(&memcg_oom_lock
);
3551 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
3552 struct eventfd_ctx
*eventfd
)
3554 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
3556 spin_lock(&memcg_oom_lock
);
3558 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
3559 if (ev
->eventfd
== eventfd
) {
3560 list_del(&ev
->list
);
3565 spin_unlock(&memcg_oom_lock
);
3568 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
3570 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
3572 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
3573 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
3577 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
3578 struct cftype
*cft
, u64 val
)
3580 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3582 /* cannot set to root cgroup and only 0 and 1 are allowed */
3583 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
3586 memcg
->oom_kill_disable
= val
;
3588 memcg_oom_recover(memcg
);
3593 #ifdef CONFIG_CGROUP_WRITEBACK
3595 struct list_head
*mem_cgroup_cgwb_list(struct mem_cgroup
*memcg
)
3597 return &memcg
->cgwb_list
;
3600 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3602 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
3605 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3607 wb_domain_exit(&memcg
->cgwb_domain
);
3610 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3612 wb_domain_size_changed(&memcg
->cgwb_domain
);
3615 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
3617 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3619 if (!memcg
->css
.parent
)
3622 return &memcg
->cgwb_domain
;
3626 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
3627 * @wb: bdi_writeback in question
3628 * @pfilepages: out parameter for number of file pages
3629 * @pheadroom: out parameter for number of allocatable pages according to memcg
3630 * @pdirty: out parameter for number of dirty pages
3631 * @pwriteback: out parameter for number of pages under writeback
3633 * Determine the numbers of file, headroom, dirty, and writeback pages in
3634 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
3635 * is a bit more involved.
3637 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
3638 * headroom is calculated as the lowest headroom of itself and the
3639 * ancestors. Note that this doesn't consider the actual amount of
3640 * available memory in the system. The caller should further cap
3641 * *@pheadroom accordingly.
3643 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
3644 unsigned long *pheadroom
, unsigned long *pdirty
,
3645 unsigned long *pwriteback
)
3647 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3648 struct mem_cgroup
*parent
;
3650 *pdirty
= mem_cgroup_read_stat(memcg
, MEM_CGROUP_STAT_DIRTY
);
3652 /* this should eventually include NR_UNSTABLE_NFS */
3653 *pwriteback
= mem_cgroup_read_stat(memcg
, MEM_CGROUP_STAT_WRITEBACK
);
3654 *pfilepages
= mem_cgroup_nr_lru_pages(memcg
, (1 << LRU_INACTIVE_FILE
) |
3655 (1 << LRU_ACTIVE_FILE
));
3656 *pheadroom
= PAGE_COUNTER_MAX
;
3658 while ((parent
= parent_mem_cgroup(memcg
))) {
3659 unsigned long ceiling
= min(memcg
->memory
.limit
, memcg
->high
);
3660 unsigned long used
= page_counter_read(&memcg
->memory
);
3662 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
3667 #else /* CONFIG_CGROUP_WRITEBACK */
3669 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3674 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3678 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3682 #endif /* CONFIG_CGROUP_WRITEBACK */
3685 * DO NOT USE IN NEW FILES.
3687 * "cgroup.event_control" implementation.
3689 * This is way over-engineered. It tries to support fully configurable
3690 * events for each user. Such level of flexibility is completely
3691 * unnecessary especially in the light of the planned unified hierarchy.
3693 * Please deprecate this and replace with something simpler if at all
3698 * Unregister event and free resources.
3700 * Gets called from workqueue.
3702 static void memcg_event_remove(struct work_struct
*work
)
3704 struct mem_cgroup_event
*event
=
3705 container_of(work
, struct mem_cgroup_event
, remove
);
3706 struct mem_cgroup
*memcg
= event
->memcg
;
3708 remove_wait_queue(event
->wqh
, &event
->wait
);
3710 event
->unregister_event(memcg
, event
->eventfd
);
3712 /* Notify userspace the event is going away. */
3713 eventfd_signal(event
->eventfd
, 1);
3715 eventfd_ctx_put(event
->eventfd
);
3717 css_put(&memcg
->css
);
3721 * Gets called on POLLHUP on eventfd when user closes it.
3723 * Called with wqh->lock held and interrupts disabled.
3725 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
3726 int sync
, void *key
)
3728 struct mem_cgroup_event
*event
=
3729 container_of(wait
, struct mem_cgroup_event
, wait
);
3730 struct mem_cgroup
*memcg
= event
->memcg
;
3731 unsigned long flags
= (unsigned long)key
;
3733 if (flags
& POLLHUP
) {
3735 * If the event has been detached at cgroup removal, we
3736 * can simply return knowing the other side will cleanup
3739 * We can't race against event freeing since the other
3740 * side will require wqh->lock via remove_wait_queue(),
3743 spin_lock(&memcg
->event_list_lock
);
3744 if (!list_empty(&event
->list
)) {
3745 list_del_init(&event
->list
);
3747 * We are in atomic context, but cgroup_event_remove()
3748 * may sleep, so we have to call it in workqueue.
3750 schedule_work(&event
->remove
);
3752 spin_unlock(&memcg
->event_list_lock
);
3758 static void memcg_event_ptable_queue_proc(struct file
*file
,
3759 wait_queue_head_t
*wqh
, poll_table
*pt
)
3761 struct mem_cgroup_event
*event
=
3762 container_of(pt
, struct mem_cgroup_event
, pt
);
3765 add_wait_queue(wqh
, &event
->wait
);
3769 * DO NOT USE IN NEW FILES.
3771 * Parse input and register new cgroup event handler.
3773 * Input must be in format '<event_fd> <control_fd> <args>'.
3774 * Interpretation of args is defined by control file implementation.
3776 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
3777 char *buf
, size_t nbytes
, loff_t off
)
3779 struct cgroup_subsys_state
*css
= of_css(of
);
3780 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3781 struct mem_cgroup_event
*event
;
3782 struct cgroup_subsys_state
*cfile_css
;
3783 unsigned int efd
, cfd
;
3790 buf
= strstrip(buf
);
3792 efd
= simple_strtoul(buf
, &endp
, 10);
3797 cfd
= simple_strtoul(buf
, &endp
, 10);
3798 if ((*endp
!= ' ') && (*endp
!= '\0'))
3802 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
3806 event
->memcg
= memcg
;
3807 INIT_LIST_HEAD(&event
->list
);
3808 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
3809 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
3810 INIT_WORK(&event
->remove
, memcg_event_remove
);
3818 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
3819 if (IS_ERR(event
->eventfd
)) {
3820 ret
= PTR_ERR(event
->eventfd
);
3827 goto out_put_eventfd
;
3830 /* the process need read permission on control file */
3831 /* AV: shouldn't we check that it's been opened for read instead? */
3832 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
3837 * Determine the event callbacks and set them in @event. This used
3838 * to be done via struct cftype but cgroup core no longer knows
3839 * about these events. The following is crude but the whole thing
3840 * is for compatibility anyway.
3842 * DO NOT ADD NEW FILES.
3844 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
3846 if (!strcmp(name
, "memory.usage_in_bytes")) {
3847 event
->register_event
= mem_cgroup_usage_register_event
;
3848 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
3849 } else if (!strcmp(name
, "memory.oom_control")) {
3850 event
->register_event
= mem_cgroup_oom_register_event
;
3851 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
3852 } else if (!strcmp(name
, "memory.pressure_level")) {
3853 event
->register_event
= vmpressure_register_event
;
3854 event
->unregister_event
= vmpressure_unregister_event
;
3855 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
3856 event
->register_event
= memsw_cgroup_usage_register_event
;
3857 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
3864 * Verify @cfile should belong to @css. Also, remaining events are
3865 * automatically removed on cgroup destruction but the removal is
3866 * asynchronous, so take an extra ref on @css.
3868 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
3869 &memory_cgrp_subsys
);
3871 if (IS_ERR(cfile_css
))
3873 if (cfile_css
!= css
) {
3878 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
3882 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
3884 spin_lock(&memcg
->event_list_lock
);
3885 list_add(&event
->list
, &memcg
->event_list
);
3886 spin_unlock(&memcg
->event_list_lock
);
3898 eventfd_ctx_put(event
->eventfd
);
3907 static struct cftype mem_cgroup_legacy_files
[] = {
3909 .name
= "usage_in_bytes",
3910 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
3911 .read_u64
= mem_cgroup_read_u64
,
3914 .name
= "max_usage_in_bytes",
3915 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
3916 .write
= mem_cgroup_reset
,
3917 .read_u64
= mem_cgroup_read_u64
,
3920 .name
= "limit_in_bytes",
3921 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
3922 .write
= mem_cgroup_write
,
3923 .read_u64
= mem_cgroup_read_u64
,
3926 .name
= "soft_limit_in_bytes",
3927 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
3928 .write
= mem_cgroup_write
,
3929 .read_u64
= mem_cgroup_read_u64
,
3933 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
3934 .write
= mem_cgroup_reset
,
3935 .read_u64
= mem_cgroup_read_u64
,
3939 .seq_show
= memcg_stat_show
,
3942 .name
= "force_empty",
3943 .write
= mem_cgroup_force_empty_write
,
3946 .name
= "use_hierarchy",
3947 .write_u64
= mem_cgroup_hierarchy_write
,
3948 .read_u64
= mem_cgroup_hierarchy_read
,
3951 .name
= "cgroup.event_control", /* XXX: for compat */
3952 .write
= memcg_write_event_control
,
3953 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
3956 .name
= "swappiness",
3957 .read_u64
= mem_cgroup_swappiness_read
,
3958 .write_u64
= mem_cgroup_swappiness_write
,
3961 .name
= "move_charge_at_immigrate",
3962 .read_u64
= mem_cgroup_move_charge_read
,
3963 .write_u64
= mem_cgroup_move_charge_write
,
3966 .name
= "oom_control",
3967 .seq_show
= mem_cgroup_oom_control_read
,
3968 .write_u64
= mem_cgroup_oom_control_write
,
3969 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
3972 .name
= "pressure_level",
3976 .name
= "numa_stat",
3977 .seq_show
= memcg_numa_stat_show
,
3981 .name
= "kmem.limit_in_bytes",
3982 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
3983 .write
= mem_cgroup_write
,
3984 .read_u64
= mem_cgroup_read_u64
,
3987 .name
= "kmem.usage_in_bytes",
3988 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
3989 .read_u64
= mem_cgroup_read_u64
,
3992 .name
= "kmem.failcnt",
3993 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
3994 .write
= mem_cgroup_reset
,
3995 .read_u64
= mem_cgroup_read_u64
,
3998 .name
= "kmem.max_usage_in_bytes",
3999 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4000 .write
= mem_cgroup_reset
,
4001 .read_u64
= mem_cgroup_read_u64
,
4003 #ifdef CONFIG_SLABINFO
4005 .name
= "kmem.slabinfo",
4006 .seq_start
= memcg_slab_start
,
4007 .seq_next
= memcg_slab_next
,
4008 .seq_stop
= memcg_slab_stop
,
4009 .seq_show
= memcg_slab_show
,
4013 .name
= "kmem.tcp.limit_in_bytes",
4014 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4015 .write
= mem_cgroup_write
,
4016 .read_u64
= mem_cgroup_read_u64
,
4019 .name
= "kmem.tcp.usage_in_bytes",
4020 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4021 .read_u64
= mem_cgroup_read_u64
,
4024 .name
= "kmem.tcp.failcnt",
4025 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4026 .write
= mem_cgroup_reset
,
4027 .read_u64
= mem_cgroup_read_u64
,
4030 .name
= "kmem.tcp.max_usage_in_bytes",
4031 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4032 .write
= mem_cgroup_reset
,
4033 .read_u64
= mem_cgroup_read_u64
,
4035 { }, /* terminate */
4039 * Private memory cgroup IDR
4041 * Swap-out records and page cache shadow entries need to store memcg
4042 * references in constrained space, so we maintain an ID space that is
4043 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4044 * memory-controlled cgroups to 64k.
4046 * However, there usually are many references to the oflline CSS after
4047 * the cgroup has been destroyed, such as page cache or reclaimable
4048 * slab objects, that don't need to hang on to the ID. We want to keep
4049 * those dead CSS from occupying IDs, or we might quickly exhaust the
4050 * relatively small ID space and prevent the creation of new cgroups
4051 * even when there are much fewer than 64k cgroups - possibly none.
4053 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4054 * be freed and recycled when it's no longer needed, which is usually
4055 * when the CSS is offlined.
4057 * The only exception to that are records of swapped out tmpfs/shmem
4058 * pages that need to be attributed to live ancestors on swapin. But
4059 * those references are manageable from userspace.
4062 static DEFINE_IDR(mem_cgroup_idr
);
4064 static void mem_cgroup_id_get_many(struct mem_cgroup
*memcg
, unsigned int n
)
4066 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) <= 0);
4067 atomic_add(n
, &memcg
->id
.ref
);
4070 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
4072 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) < n
);
4073 if (atomic_sub_and_test(n
, &memcg
->id
.ref
)) {
4074 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4077 /* Memcg ID pins CSS */
4078 css_put(&memcg
->css
);
4082 static inline void mem_cgroup_id_get(struct mem_cgroup
*memcg
)
4084 mem_cgroup_id_get_many(memcg
, 1);
4087 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
4089 mem_cgroup_id_put_many(memcg
, 1);
4093 * mem_cgroup_from_id - look up a memcg from a memcg id
4094 * @id: the memcg id to look up
4096 * Caller must hold rcu_read_lock().
4098 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
4100 WARN_ON_ONCE(!rcu_read_lock_held());
4101 return idr_find(&mem_cgroup_idr
, id
);
4104 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4106 struct mem_cgroup_per_node
*pn
;
4109 * This routine is called against possible nodes.
4110 * But it's BUG to call kmalloc() against offline node.
4112 * TODO: this routine can waste much memory for nodes which will
4113 * never be onlined. It's better to use memory hotplug callback
4116 if (!node_state(node
, N_NORMAL_MEMORY
))
4118 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4122 lruvec_init(&pn
->lruvec
);
4123 pn
->usage_in_excess
= 0;
4124 pn
->on_tree
= false;
4127 memcg
->nodeinfo
[node
] = pn
;
4131 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4133 kfree(memcg
->nodeinfo
[node
]);
4136 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
4140 memcg_wb_domain_exit(memcg
);
4142 free_mem_cgroup_per_node_info(memcg
, node
);
4143 free_percpu(memcg
->stat
);
4147 static struct mem_cgroup
*mem_cgroup_alloc(void)
4149 struct mem_cgroup
*memcg
;
4153 size
= sizeof(struct mem_cgroup
);
4154 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
4156 memcg
= kzalloc(size
, GFP_KERNEL
);
4160 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
4161 1, MEM_CGROUP_ID_MAX
,
4163 if (memcg
->id
.id
< 0)
4166 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
4171 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
4174 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
4177 INIT_WORK(&memcg
->high_work
, high_work_func
);
4178 memcg
->last_scanned_node
= MAX_NUMNODES
;
4179 INIT_LIST_HEAD(&memcg
->oom_notify
);
4180 mutex_init(&memcg
->thresholds_lock
);
4181 spin_lock_init(&memcg
->move_lock
);
4182 vmpressure_init(&memcg
->vmpressure
);
4183 INIT_LIST_HEAD(&memcg
->event_list
);
4184 spin_lock_init(&memcg
->event_list_lock
);
4185 memcg
->socket_pressure
= jiffies
;
4187 memcg
->kmemcg_id
= -1;
4189 #ifdef CONFIG_CGROUP_WRITEBACK
4190 INIT_LIST_HEAD(&memcg
->cgwb_list
);
4192 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
4195 if (memcg
->id
.id
> 0)
4196 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4197 mem_cgroup_free(memcg
);
4201 static struct cgroup_subsys_state
* __ref
4202 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
4204 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
4205 struct mem_cgroup
*memcg
;
4206 long error
= -ENOMEM
;
4208 memcg
= mem_cgroup_alloc();
4210 return ERR_PTR(error
);
4212 memcg
->high
= PAGE_COUNTER_MAX
;
4213 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4215 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
4216 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
4218 if (parent
&& parent
->use_hierarchy
) {
4219 memcg
->use_hierarchy
= true;
4220 page_counter_init(&memcg
->memory
, &parent
->memory
);
4221 page_counter_init(&memcg
->swap
, &parent
->swap
);
4222 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
4223 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
4224 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
4226 page_counter_init(&memcg
->memory
, NULL
);
4227 page_counter_init(&memcg
->swap
, NULL
);
4228 page_counter_init(&memcg
->memsw
, NULL
);
4229 page_counter_init(&memcg
->kmem
, NULL
);
4230 page_counter_init(&memcg
->tcpmem
, NULL
);
4232 * Deeper hierachy with use_hierarchy == false doesn't make
4233 * much sense so let cgroup subsystem know about this
4234 * unfortunate state in our controller.
4236 if (parent
!= root_mem_cgroup
)
4237 memory_cgrp_subsys
.broken_hierarchy
= true;
4240 /* The following stuff does not apply to the root */
4242 root_mem_cgroup
= memcg
;
4246 error
= memcg_online_kmem(memcg
);
4250 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4251 static_branch_inc(&memcg_sockets_enabled_key
);
4255 mem_cgroup_free(memcg
);
4256 return ERR_PTR(-ENOMEM
);
4259 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
4261 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4263 /* Online state pins memcg ID, memcg ID pins CSS */
4264 atomic_set(&memcg
->id
.ref
, 1);
4269 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
4271 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4272 struct mem_cgroup_event
*event
, *tmp
;
4275 * Unregister events and notify userspace.
4276 * Notify userspace about cgroup removing only after rmdir of cgroup
4277 * directory to avoid race between userspace and kernelspace.
4279 spin_lock(&memcg
->event_list_lock
);
4280 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
4281 list_del_init(&event
->list
);
4282 schedule_work(&event
->remove
);
4284 spin_unlock(&memcg
->event_list_lock
);
4286 memcg_offline_kmem(memcg
);
4287 wb_memcg_offline(memcg
);
4289 mem_cgroup_id_put(memcg
);
4292 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
4294 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4296 invalidate_reclaim_iterators(memcg
);
4299 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
4301 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4303 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4304 static_branch_dec(&memcg_sockets_enabled_key
);
4306 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
4307 static_branch_dec(&memcg_sockets_enabled_key
);
4309 vmpressure_cleanup(&memcg
->vmpressure
);
4310 cancel_work_sync(&memcg
->high_work
);
4311 mem_cgroup_remove_from_trees(memcg
);
4312 memcg_free_kmem(memcg
);
4313 mem_cgroup_free(memcg
);
4317 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4318 * @css: the target css
4320 * Reset the states of the mem_cgroup associated with @css. This is
4321 * invoked when the userland requests disabling on the default hierarchy
4322 * but the memcg is pinned through dependency. The memcg should stop
4323 * applying policies and should revert to the vanilla state as it may be
4324 * made visible again.
4326 * The current implementation only resets the essential configurations.
4327 * This needs to be expanded to cover all the visible parts.
4329 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
4331 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4333 page_counter_limit(&memcg
->memory
, PAGE_COUNTER_MAX
);
4334 page_counter_limit(&memcg
->swap
, PAGE_COUNTER_MAX
);
4335 page_counter_limit(&memcg
->memsw
, PAGE_COUNTER_MAX
);
4336 page_counter_limit(&memcg
->kmem
, PAGE_COUNTER_MAX
);
4337 page_counter_limit(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
4339 memcg
->high
= PAGE_COUNTER_MAX
;
4340 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4341 memcg_wb_domain_size_changed(memcg
);
4345 /* Handlers for move charge at task migration. */
4346 static int mem_cgroup_do_precharge(unsigned long count
)
4350 /* Try a single bulk charge without reclaim first, kswapd may wake */
4351 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
4353 mc
.precharge
+= count
;
4357 /* Try charges one by one with reclaim, but do not retry */
4359 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
4373 enum mc_target_type
{
4379 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
4380 unsigned long addr
, pte_t ptent
)
4382 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
4384 if (!page
|| !page_mapped(page
))
4386 if (PageAnon(page
)) {
4387 if (!(mc
.flags
& MOVE_ANON
))
4390 if (!(mc
.flags
& MOVE_FILE
))
4393 if (!get_page_unless_zero(page
))
4400 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4401 pte_t ptent
, swp_entry_t
*entry
)
4403 struct page
*page
= NULL
;
4404 swp_entry_t ent
= pte_to_swp_entry(ptent
);
4406 if (!(mc
.flags
& MOVE_ANON
) || non_swap_entry(ent
))
4409 * Because lookup_swap_cache() updates some statistics counter,
4410 * we call find_get_page() with swapper_space directly.
4412 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
4413 if (do_memsw_account())
4414 entry
->val
= ent
.val
;
4419 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4420 pte_t ptent
, swp_entry_t
*entry
)
4426 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
4427 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
4429 struct page
*page
= NULL
;
4430 struct address_space
*mapping
;
4433 if (!vma
->vm_file
) /* anonymous vma */
4435 if (!(mc
.flags
& MOVE_FILE
))
4438 mapping
= vma
->vm_file
->f_mapping
;
4439 pgoff
= linear_page_index(vma
, addr
);
4441 /* page is moved even if it's not RSS of this task(page-faulted). */
4443 /* shmem/tmpfs may report page out on swap: account for that too. */
4444 if (shmem_mapping(mapping
)) {
4445 page
= find_get_entry(mapping
, pgoff
);
4446 if (radix_tree_exceptional_entry(page
)) {
4447 swp_entry_t swp
= radix_to_swp_entry(page
);
4448 if (do_memsw_account())
4450 page
= find_get_page(swap_address_space(swp
),
4454 page
= find_get_page(mapping
, pgoff
);
4456 page
= find_get_page(mapping
, pgoff
);
4462 * mem_cgroup_move_account - move account of the page
4464 * @compound: charge the page as compound or small page
4465 * @from: mem_cgroup which the page is moved from.
4466 * @to: mem_cgroup which the page is moved to. @from != @to.
4468 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
4470 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
4473 static int mem_cgroup_move_account(struct page
*page
,
4475 struct mem_cgroup
*from
,
4476 struct mem_cgroup
*to
)
4478 unsigned long flags
;
4479 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
4483 VM_BUG_ON(from
== to
);
4484 VM_BUG_ON_PAGE(PageLRU(page
), page
);
4485 VM_BUG_ON(compound
&& !PageTransHuge(page
));
4488 * Prevent mem_cgroup_migrate() from looking at
4489 * page->mem_cgroup of its source page while we change it.
4492 if (!trylock_page(page
))
4496 if (page
->mem_cgroup
!= from
)
4499 anon
= PageAnon(page
);
4501 spin_lock_irqsave(&from
->move_lock
, flags
);
4503 if (!anon
&& page_mapped(page
)) {
4504 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
4506 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
4511 * move_lock grabbed above and caller set from->moving_account, so
4512 * mem_cgroup_update_page_stat() will serialize updates to PageDirty.
4513 * So mapping should be stable for dirty pages.
4515 if (!anon
&& PageDirty(page
)) {
4516 struct address_space
*mapping
= page_mapping(page
);
4518 if (mapping_cap_account_dirty(mapping
)) {
4519 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_DIRTY
],
4521 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_DIRTY
],
4526 if (PageWriteback(page
)) {
4527 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
4529 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
4534 * It is safe to change page->mem_cgroup here because the page
4535 * is referenced, charged, and isolated - we can't race with
4536 * uncharging, charging, migration, or LRU putback.
4539 /* caller should have done css_get */
4540 page
->mem_cgroup
= to
;
4541 spin_unlock_irqrestore(&from
->move_lock
, flags
);
4545 local_irq_disable();
4546 mem_cgroup_charge_statistics(to
, page
, compound
, nr_pages
);
4547 memcg_check_events(to
, page
);
4548 mem_cgroup_charge_statistics(from
, page
, compound
, -nr_pages
);
4549 memcg_check_events(from
, page
);
4558 * get_mctgt_type - get target type of moving charge
4559 * @vma: the vma the pte to be checked belongs
4560 * @addr: the address corresponding to the pte to be checked
4561 * @ptent: the pte to be checked
4562 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4565 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4566 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4567 * move charge. if @target is not NULL, the page is stored in target->page
4568 * with extra refcnt got(Callers should handle it).
4569 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4570 * target for charge migration. if @target is not NULL, the entry is stored
4573 * Called with pte lock held.
4576 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
4577 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
4579 struct page
*page
= NULL
;
4580 enum mc_target_type ret
= MC_TARGET_NONE
;
4581 swp_entry_t ent
= { .val
= 0 };
4583 if (pte_present(ptent
))
4584 page
= mc_handle_present_pte(vma
, addr
, ptent
);
4585 else if (is_swap_pte(ptent
))
4586 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
4587 else if (pte_none(ptent
))
4588 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
4590 if (!page
&& !ent
.val
)
4594 * Do only loose check w/o serialization.
4595 * mem_cgroup_move_account() checks the page is valid or
4596 * not under LRU exclusion.
4598 if (page
->mem_cgroup
== mc
.from
) {
4599 ret
= MC_TARGET_PAGE
;
4601 target
->page
= page
;
4603 if (!ret
|| !target
)
4606 /* There is a swap entry and a page doesn't exist or isn't charged */
4607 if (ent
.val
&& !ret
&&
4608 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
4609 ret
= MC_TARGET_SWAP
;
4616 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4618 * We don't consider swapping or file mapped pages because THP does not
4619 * support them for now.
4620 * Caller should make sure that pmd_trans_huge(pmd) is true.
4622 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4623 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4625 struct page
*page
= NULL
;
4626 enum mc_target_type ret
= MC_TARGET_NONE
;
4628 page
= pmd_page(pmd
);
4629 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
4630 if (!(mc
.flags
& MOVE_ANON
))
4632 if (page
->mem_cgroup
== mc
.from
) {
4633 ret
= MC_TARGET_PAGE
;
4636 target
->page
= page
;
4642 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4643 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4645 return MC_TARGET_NONE
;
4649 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
4650 unsigned long addr
, unsigned long end
,
4651 struct mm_walk
*walk
)
4653 struct vm_area_struct
*vma
= walk
->vma
;
4657 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4659 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
4660 mc
.precharge
+= HPAGE_PMD_NR
;
4665 if (pmd_trans_unstable(pmd
))
4667 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4668 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
4669 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
4670 mc
.precharge
++; /* increment precharge temporarily */
4671 pte_unmap_unlock(pte
- 1, ptl
);
4677 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
4679 unsigned long precharge
;
4681 struct mm_walk mem_cgroup_count_precharge_walk
= {
4682 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
4685 down_read(&mm
->mmap_sem
);
4686 walk_page_range(0, mm
->highest_vm_end
,
4687 &mem_cgroup_count_precharge_walk
);
4688 up_read(&mm
->mmap_sem
);
4690 precharge
= mc
.precharge
;
4696 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
4698 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
4700 VM_BUG_ON(mc
.moving_task
);
4701 mc
.moving_task
= current
;
4702 return mem_cgroup_do_precharge(precharge
);
4705 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4706 static void __mem_cgroup_clear_mc(void)
4708 struct mem_cgroup
*from
= mc
.from
;
4709 struct mem_cgroup
*to
= mc
.to
;
4711 /* we must uncharge all the leftover precharges from mc.to */
4713 cancel_charge(mc
.to
, mc
.precharge
);
4717 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4718 * we must uncharge here.
4720 if (mc
.moved_charge
) {
4721 cancel_charge(mc
.from
, mc
.moved_charge
);
4722 mc
.moved_charge
= 0;
4724 /* we must fixup refcnts and charges */
4725 if (mc
.moved_swap
) {
4726 /* uncharge swap account from the old cgroup */
4727 if (!mem_cgroup_is_root(mc
.from
))
4728 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
4730 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
4733 * we charged both to->memory and to->memsw, so we
4734 * should uncharge to->memory.
4736 if (!mem_cgroup_is_root(mc
.to
))
4737 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
4739 mem_cgroup_id_get_many(mc
.to
, mc
.moved_swap
);
4740 css_put_many(&mc
.to
->css
, mc
.moved_swap
);
4744 memcg_oom_recover(from
);
4745 memcg_oom_recover(to
);
4746 wake_up_all(&mc
.waitq
);
4749 static void mem_cgroup_clear_mc(void)
4751 struct mm_struct
*mm
= mc
.mm
;
4754 * we must clear moving_task before waking up waiters at the end of
4757 mc
.moving_task
= NULL
;
4758 __mem_cgroup_clear_mc();
4759 spin_lock(&mc
.lock
);
4763 spin_unlock(&mc
.lock
);
4768 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
4770 struct cgroup_subsys_state
*css
;
4771 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
4772 struct mem_cgroup
*from
;
4773 struct task_struct
*leader
, *p
;
4774 struct mm_struct
*mm
;
4775 unsigned long move_flags
;
4778 /* charge immigration isn't supported on the default hierarchy */
4779 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
4783 * Multi-process migrations only happen on the default hierarchy
4784 * where charge immigration is not used. Perform charge
4785 * immigration if @tset contains a leader and whine if there are
4789 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
4792 memcg
= mem_cgroup_from_css(css
);
4798 * We are now commited to this value whatever it is. Changes in this
4799 * tunable will only affect upcoming migrations, not the current one.
4800 * So we need to save it, and keep it going.
4802 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
4806 from
= mem_cgroup_from_task(p
);
4808 VM_BUG_ON(from
== memcg
);
4810 mm
= get_task_mm(p
);
4813 /* We move charges only when we move a owner of the mm */
4814 if (mm
->owner
== p
) {
4817 VM_BUG_ON(mc
.precharge
);
4818 VM_BUG_ON(mc
.moved_charge
);
4819 VM_BUG_ON(mc
.moved_swap
);
4821 spin_lock(&mc
.lock
);
4825 mc
.flags
= move_flags
;
4826 spin_unlock(&mc
.lock
);
4827 /* We set mc.moving_task later */
4829 ret
= mem_cgroup_precharge_mc(mm
);
4831 mem_cgroup_clear_mc();
4838 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
4841 mem_cgroup_clear_mc();
4844 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
4845 unsigned long addr
, unsigned long end
,
4846 struct mm_walk
*walk
)
4849 struct vm_area_struct
*vma
= walk
->vma
;
4852 enum mc_target_type target_type
;
4853 union mc_target target
;
4856 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4858 if (mc
.precharge
< HPAGE_PMD_NR
) {
4862 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
4863 if (target_type
== MC_TARGET_PAGE
) {
4865 if (!isolate_lru_page(page
)) {
4866 if (!mem_cgroup_move_account(page
, true,
4868 mc
.precharge
-= HPAGE_PMD_NR
;
4869 mc
.moved_charge
+= HPAGE_PMD_NR
;
4871 putback_lru_page(page
);
4879 if (pmd_trans_unstable(pmd
))
4882 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4883 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
4884 pte_t ptent
= *(pte
++);
4890 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
4891 case MC_TARGET_PAGE
:
4894 * We can have a part of the split pmd here. Moving it
4895 * can be done but it would be too convoluted so simply
4896 * ignore such a partial THP and keep it in original
4897 * memcg. There should be somebody mapping the head.
4899 if (PageTransCompound(page
))
4901 if (isolate_lru_page(page
))
4903 if (!mem_cgroup_move_account(page
, false,
4906 /* we uncharge from mc.from later. */
4909 putback_lru_page(page
);
4910 put
: /* get_mctgt_type() gets the page */
4913 case MC_TARGET_SWAP
:
4915 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
4917 /* we fixup refcnts and charges later. */
4925 pte_unmap_unlock(pte
- 1, ptl
);
4930 * We have consumed all precharges we got in can_attach().
4931 * We try charge one by one, but don't do any additional
4932 * charges to mc.to if we have failed in charge once in attach()
4935 ret
= mem_cgroup_do_precharge(1);
4943 static void mem_cgroup_move_charge(void)
4945 struct mm_walk mem_cgroup_move_charge_walk
= {
4946 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
4950 lru_add_drain_all();
4952 * Signal lock_page_memcg() to take the memcg's move_lock
4953 * while we're moving its pages to another memcg. Then wait
4954 * for already started RCU-only updates to finish.
4956 atomic_inc(&mc
.from
->moving_account
);
4959 if (unlikely(!down_read_trylock(&mc
.mm
->mmap_sem
))) {
4961 * Someone who are holding the mmap_sem might be waiting in
4962 * waitq. So we cancel all extra charges, wake up all waiters,
4963 * and retry. Because we cancel precharges, we might not be able
4964 * to move enough charges, but moving charge is a best-effort
4965 * feature anyway, so it wouldn't be a big problem.
4967 __mem_cgroup_clear_mc();
4972 * When we have consumed all precharges and failed in doing
4973 * additional charge, the page walk just aborts.
4975 walk_page_range(0, mc
.mm
->highest_vm_end
, &mem_cgroup_move_charge_walk
);
4977 up_read(&mc
.mm
->mmap_sem
);
4978 atomic_dec(&mc
.from
->moving_account
);
4981 static void mem_cgroup_move_task(void)
4984 mem_cgroup_move_charge();
4985 mem_cgroup_clear_mc();
4988 #else /* !CONFIG_MMU */
4989 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
4993 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
4996 static void mem_cgroup_move_task(void)
5002 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5003 * to verify whether we're attached to the default hierarchy on each mount
5006 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5009 * use_hierarchy is forced on the default hierarchy. cgroup core
5010 * guarantees that @root doesn't have any children, so turning it
5011 * on for the root memcg is enough.
5013 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5014 root_mem_cgroup
->use_hierarchy
= true;
5016 root_mem_cgroup
->use_hierarchy
= false;
5019 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
5022 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5024 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
5027 static int memory_low_show(struct seq_file
*m
, void *v
)
5029 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5030 unsigned long low
= READ_ONCE(memcg
->low
);
5032 if (low
== PAGE_COUNTER_MAX
)
5033 seq_puts(m
, "max\n");
5035 seq_printf(m
, "%llu\n", (u64
)low
* PAGE_SIZE
);
5040 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
5041 char *buf
, size_t nbytes
, loff_t off
)
5043 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5047 buf
= strstrip(buf
);
5048 err
= page_counter_memparse(buf
, "max", &low
);
5057 static int memory_high_show(struct seq_file
*m
, void *v
)
5059 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5060 unsigned long high
= READ_ONCE(memcg
->high
);
5062 if (high
== PAGE_COUNTER_MAX
)
5063 seq_puts(m
, "max\n");
5065 seq_printf(m
, "%llu\n", (u64
)high
* PAGE_SIZE
);
5070 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
5071 char *buf
, size_t nbytes
, loff_t off
)
5073 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5074 unsigned long nr_pages
;
5078 buf
= strstrip(buf
);
5079 err
= page_counter_memparse(buf
, "max", &high
);
5085 nr_pages
= page_counter_read(&memcg
->memory
);
5086 if (nr_pages
> high
)
5087 try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
5090 memcg_wb_domain_size_changed(memcg
);
5094 static int memory_max_show(struct seq_file
*m
, void *v
)
5096 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5097 unsigned long max
= READ_ONCE(memcg
->memory
.limit
);
5099 if (max
== PAGE_COUNTER_MAX
)
5100 seq_puts(m
, "max\n");
5102 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
5107 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
5108 char *buf
, size_t nbytes
, loff_t off
)
5110 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5111 unsigned int nr_reclaims
= MEM_CGROUP_RECLAIM_RETRIES
;
5112 bool drained
= false;
5116 buf
= strstrip(buf
);
5117 err
= page_counter_memparse(buf
, "max", &max
);
5121 xchg(&memcg
->memory
.limit
, max
);
5124 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
5126 if (nr_pages
<= max
)
5129 if (signal_pending(current
)) {
5135 drain_all_stock(memcg
);
5141 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
5147 mem_cgroup_events(memcg
, MEMCG_OOM
, 1);
5148 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
5152 memcg_wb_domain_size_changed(memcg
);
5156 static int memory_events_show(struct seq_file
*m
, void *v
)
5158 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5160 seq_printf(m
, "low %lu\n", mem_cgroup_read_events(memcg
, MEMCG_LOW
));
5161 seq_printf(m
, "high %lu\n", mem_cgroup_read_events(memcg
, MEMCG_HIGH
));
5162 seq_printf(m
, "max %lu\n", mem_cgroup_read_events(memcg
, MEMCG_MAX
));
5163 seq_printf(m
, "oom %lu\n", mem_cgroup_read_events(memcg
, MEMCG_OOM
));
5168 static int memory_stat_show(struct seq_file
*m
, void *v
)
5170 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5171 unsigned long stat
[MEMCG_NR_STAT
];
5172 unsigned long events
[MEMCG_NR_EVENTS
];
5176 * Provide statistics on the state of the memory subsystem as
5177 * well as cumulative event counters that show past behavior.
5179 * This list is ordered following a combination of these gradients:
5180 * 1) generic big picture -> specifics and details
5181 * 2) reflecting userspace activity -> reflecting kernel heuristics
5183 * Current memory state:
5186 tree_stat(memcg
, stat
);
5187 tree_events(memcg
, events
);
5189 seq_printf(m
, "anon %llu\n",
5190 (u64
)stat
[MEM_CGROUP_STAT_RSS
] * PAGE_SIZE
);
5191 seq_printf(m
, "file %llu\n",
5192 (u64
)stat
[MEM_CGROUP_STAT_CACHE
] * PAGE_SIZE
);
5193 seq_printf(m
, "kernel_stack %llu\n",
5194 (u64
)stat
[MEMCG_KERNEL_STACK_KB
] * 1024);
5195 seq_printf(m
, "slab %llu\n",
5196 (u64
)(stat
[MEMCG_SLAB_RECLAIMABLE
] +
5197 stat
[MEMCG_SLAB_UNRECLAIMABLE
]) * PAGE_SIZE
);
5198 seq_printf(m
, "sock %llu\n",
5199 (u64
)stat
[MEMCG_SOCK
] * PAGE_SIZE
);
5201 seq_printf(m
, "file_mapped %llu\n",
5202 (u64
)stat
[MEM_CGROUP_STAT_FILE_MAPPED
] * PAGE_SIZE
);
5203 seq_printf(m
, "file_dirty %llu\n",
5204 (u64
)stat
[MEM_CGROUP_STAT_DIRTY
] * PAGE_SIZE
);
5205 seq_printf(m
, "file_writeback %llu\n",
5206 (u64
)stat
[MEM_CGROUP_STAT_WRITEBACK
] * PAGE_SIZE
);
5208 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5209 struct mem_cgroup
*mi
;
5210 unsigned long val
= 0;
5212 for_each_mem_cgroup_tree(mi
, memcg
)
5213 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
));
5214 seq_printf(m
, "%s %llu\n",
5215 mem_cgroup_lru_names
[i
], (u64
)val
* PAGE_SIZE
);
5218 seq_printf(m
, "slab_reclaimable %llu\n",
5219 (u64
)stat
[MEMCG_SLAB_RECLAIMABLE
] * PAGE_SIZE
);
5220 seq_printf(m
, "slab_unreclaimable %llu\n",
5221 (u64
)stat
[MEMCG_SLAB_UNRECLAIMABLE
] * PAGE_SIZE
);
5223 /* Accumulated memory events */
5225 seq_printf(m
, "pgfault %lu\n",
5226 events
[MEM_CGROUP_EVENTS_PGFAULT
]);
5227 seq_printf(m
, "pgmajfault %lu\n",
5228 events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
5233 static struct cftype memory_files
[] = {
5236 .flags
= CFTYPE_NOT_ON_ROOT
,
5237 .read_u64
= memory_current_read
,
5241 .flags
= CFTYPE_NOT_ON_ROOT
,
5242 .seq_show
= memory_low_show
,
5243 .write
= memory_low_write
,
5247 .flags
= CFTYPE_NOT_ON_ROOT
,
5248 .seq_show
= memory_high_show
,
5249 .write
= memory_high_write
,
5253 .flags
= CFTYPE_NOT_ON_ROOT
,
5254 .seq_show
= memory_max_show
,
5255 .write
= memory_max_write
,
5259 .flags
= CFTYPE_NOT_ON_ROOT
,
5260 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
5261 .seq_show
= memory_events_show
,
5265 .flags
= CFTYPE_NOT_ON_ROOT
,
5266 .seq_show
= memory_stat_show
,
5271 struct cgroup_subsys memory_cgrp_subsys
= {
5272 .css_alloc
= mem_cgroup_css_alloc
,
5273 .css_online
= mem_cgroup_css_online
,
5274 .css_offline
= mem_cgroup_css_offline
,
5275 .css_released
= mem_cgroup_css_released
,
5276 .css_free
= mem_cgroup_css_free
,
5277 .css_reset
= mem_cgroup_css_reset
,
5278 .can_attach
= mem_cgroup_can_attach
,
5279 .cancel_attach
= mem_cgroup_cancel_attach
,
5280 .post_attach
= mem_cgroup_move_task
,
5281 .bind
= mem_cgroup_bind
,
5282 .dfl_cftypes
= memory_files
,
5283 .legacy_cftypes
= mem_cgroup_legacy_files
,
5288 * mem_cgroup_low - check if memory consumption is below the normal range
5289 * @root: the highest ancestor to consider
5290 * @memcg: the memory cgroup to check
5292 * Returns %true if memory consumption of @memcg, and that of all
5293 * configurable ancestors up to @root, is below the normal range.
5295 bool mem_cgroup_low(struct mem_cgroup
*root
, struct mem_cgroup
*memcg
)
5297 if (mem_cgroup_disabled())
5301 * The toplevel group doesn't have a configurable range, so
5302 * it's never low when looked at directly, and it is not
5303 * considered an ancestor when assessing the hierarchy.
5306 if (memcg
== root_mem_cgroup
)
5309 if (page_counter_read(&memcg
->memory
) >= memcg
->low
)
5312 while (memcg
!= root
) {
5313 memcg
= parent_mem_cgroup(memcg
);
5315 if (memcg
== root_mem_cgroup
)
5318 if (page_counter_read(&memcg
->memory
) >= memcg
->low
)
5325 * mem_cgroup_try_charge - try charging a page
5326 * @page: page to charge
5327 * @mm: mm context of the victim
5328 * @gfp_mask: reclaim mode
5329 * @memcgp: charged memcg return
5330 * @compound: charge the page as compound or small page
5332 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5333 * pages according to @gfp_mask if necessary.
5335 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5336 * Otherwise, an error code is returned.
5338 * After page->mapping has been set up, the caller must finalize the
5339 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5340 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5342 int mem_cgroup_try_charge(struct page
*page
, struct mm_struct
*mm
,
5343 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
,
5346 struct mem_cgroup
*memcg
= NULL
;
5347 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5350 if (mem_cgroup_disabled())
5353 if (PageSwapCache(page
)) {
5355 * Every swap fault against a single page tries to charge the
5356 * page, bail as early as possible. shmem_unuse() encounters
5357 * already charged pages, too. The USED bit is protected by
5358 * the page lock, which serializes swap cache removal, which
5359 * in turn serializes uncharging.
5361 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
5362 if (page
->mem_cgroup
)
5365 if (do_swap_account
) {
5366 swp_entry_t ent
= { .val
= page_private(page
), };
5367 unsigned short id
= lookup_swap_cgroup_id(ent
);
5370 memcg
= mem_cgroup_from_id(id
);
5371 if (memcg
&& !css_tryget_online(&memcg
->css
))
5378 memcg
= get_mem_cgroup_from_mm(mm
);
5380 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
5382 css_put(&memcg
->css
);
5389 * mem_cgroup_commit_charge - commit a page charge
5390 * @page: page to charge
5391 * @memcg: memcg to charge the page to
5392 * @lrucare: page might be on LRU already
5393 * @compound: charge the page as compound or small page
5395 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5396 * after page->mapping has been set up. This must happen atomically
5397 * as part of the page instantiation, i.e. under the page table lock
5398 * for anonymous pages, under the page lock for page and swap cache.
5400 * In addition, the page must not be on the LRU during the commit, to
5401 * prevent racing with task migration. If it might be, use @lrucare.
5403 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5405 void mem_cgroup_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5406 bool lrucare
, bool compound
)
5408 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5410 VM_BUG_ON_PAGE(!page
->mapping
, page
);
5411 VM_BUG_ON_PAGE(PageLRU(page
) && !lrucare
, page
);
5413 if (mem_cgroup_disabled())
5416 * Swap faults will attempt to charge the same page multiple
5417 * times. But reuse_swap_page() might have removed the page
5418 * from swapcache already, so we can't check PageSwapCache().
5423 commit_charge(page
, memcg
, lrucare
);
5425 local_irq_disable();
5426 mem_cgroup_charge_statistics(memcg
, page
, compound
, nr_pages
);
5427 memcg_check_events(memcg
, page
);
5430 if (do_memsw_account() && PageSwapCache(page
)) {
5431 swp_entry_t entry
= { .val
= page_private(page
) };
5433 * The swap entry might not get freed for a long time,
5434 * let's not wait for it. The page already received a
5435 * memory+swap charge, drop the swap entry duplicate.
5437 mem_cgroup_uncharge_swap(entry
);
5442 * mem_cgroup_cancel_charge - cancel a page charge
5443 * @page: page to charge
5444 * @memcg: memcg to charge the page to
5445 * @compound: charge the page as compound or small page
5447 * Cancel a charge transaction started by mem_cgroup_try_charge().
5449 void mem_cgroup_cancel_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5452 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5454 if (mem_cgroup_disabled())
5457 * Swap faults will attempt to charge the same page multiple
5458 * times. But reuse_swap_page() might have removed the page
5459 * from swapcache already, so we can't check PageSwapCache().
5464 cancel_charge(memcg
, nr_pages
);
5467 static void uncharge_batch(struct mem_cgroup
*memcg
, unsigned long pgpgout
,
5468 unsigned long nr_anon
, unsigned long nr_file
,
5469 unsigned long nr_huge
, unsigned long nr_kmem
,
5470 struct page
*dummy_page
)
5472 unsigned long nr_pages
= nr_anon
+ nr_file
+ nr_kmem
;
5473 unsigned long flags
;
5475 if (!mem_cgroup_is_root(memcg
)) {
5476 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5477 if (do_memsw_account())
5478 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
5479 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && nr_kmem
)
5480 page_counter_uncharge(&memcg
->kmem
, nr_kmem
);
5481 memcg_oom_recover(memcg
);
5484 local_irq_save(flags
);
5485 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
], nr_anon
);
5486 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
], nr_file
);
5487 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
], nr_huge
);
5488 __this_cpu_add(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
], pgpgout
);
5489 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
5490 memcg_check_events(memcg
, dummy_page
);
5491 local_irq_restore(flags
);
5493 if (!mem_cgroup_is_root(memcg
))
5494 css_put_many(&memcg
->css
, nr_pages
);
5497 static void uncharge_list(struct list_head
*page_list
)
5499 struct mem_cgroup
*memcg
= NULL
;
5500 unsigned long nr_anon
= 0;
5501 unsigned long nr_file
= 0;
5502 unsigned long nr_huge
= 0;
5503 unsigned long nr_kmem
= 0;
5504 unsigned long pgpgout
= 0;
5505 struct list_head
*next
;
5509 * Note that the list can be a single page->lru; hence the
5510 * do-while loop instead of a simple list_for_each_entry().
5512 next
= page_list
->next
;
5514 page
= list_entry(next
, struct page
, lru
);
5515 next
= page
->lru
.next
;
5517 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5518 VM_BUG_ON_PAGE(page_count(page
), page
);
5520 if (!page
->mem_cgroup
)
5524 * Nobody should be changing or seriously looking at
5525 * page->mem_cgroup at this point, we have fully
5526 * exclusive access to the page.
5529 if (memcg
!= page
->mem_cgroup
) {
5531 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5532 nr_huge
, nr_kmem
, page
);
5533 pgpgout
= nr_anon
= nr_file
=
5534 nr_huge
= nr_kmem
= 0;
5536 memcg
= page
->mem_cgroup
;
5539 if (!PageKmemcg(page
)) {
5540 unsigned int nr_pages
= 1;
5542 if (PageTransHuge(page
)) {
5543 nr_pages
<<= compound_order(page
);
5544 nr_huge
+= nr_pages
;
5547 nr_anon
+= nr_pages
;
5549 nr_file
+= nr_pages
;
5552 nr_kmem
+= 1 << compound_order(page
);
5553 __ClearPageKmemcg(page
);
5556 page
->mem_cgroup
= NULL
;
5557 } while (next
!= page_list
);
5560 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5561 nr_huge
, nr_kmem
, page
);
5565 * mem_cgroup_uncharge - uncharge a page
5566 * @page: page to uncharge
5568 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5569 * mem_cgroup_commit_charge().
5571 void mem_cgroup_uncharge(struct page
*page
)
5573 if (mem_cgroup_disabled())
5576 /* Don't touch page->lru of any random page, pre-check: */
5577 if (!page
->mem_cgroup
)
5580 INIT_LIST_HEAD(&page
->lru
);
5581 uncharge_list(&page
->lru
);
5585 * mem_cgroup_uncharge_list - uncharge a list of page
5586 * @page_list: list of pages to uncharge
5588 * Uncharge a list of pages previously charged with
5589 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5591 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
5593 if (mem_cgroup_disabled())
5596 if (!list_empty(page_list
))
5597 uncharge_list(page_list
);
5601 * mem_cgroup_migrate - charge a page's replacement
5602 * @oldpage: currently circulating page
5603 * @newpage: replacement page
5605 * Charge @newpage as a replacement page for @oldpage. @oldpage will
5606 * be uncharged upon free.
5608 * Both pages must be locked, @newpage->mapping must be set up.
5610 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
5612 struct mem_cgroup
*memcg
;
5613 unsigned int nr_pages
;
5615 unsigned long flags
;
5617 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
5618 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
5619 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
5620 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
5623 if (mem_cgroup_disabled())
5626 /* Page cache replacement: new page already charged? */
5627 if (newpage
->mem_cgroup
)
5630 /* Swapcache readahead pages can get replaced before being charged */
5631 memcg
= oldpage
->mem_cgroup
;
5635 /* Force-charge the new page. The old one will be freed soon */
5636 compound
= PageTransHuge(newpage
);
5637 nr_pages
= compound
? hpage_nr_pages(newpage
) : 1;
5639 page_counter_charge(&memcg
->memory
, nr_pages
);
5640 if (do_memsw_account())
5641 page_counter_charge(&memcg
->memsw
, nr_pages
);
5642 css_get_many(&memcg
->css
, nr_pages
);
5644 commit_charge(newpage
, memcg
, false);
5646 local_irq_save(flags
);
5647 mem_cgroup_charge_statistics(memcg
, newpage
, compound
, nr_pages
);
5648 memcg_check_events(memcg
, newpage
);
5649 local_irq_restore(flags
);
5652 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
5653 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
5655 void mem_cgroup_sk_alloc(struct sock
*sk
)
5657 struct mem_cgroup
*memcg
;
5659 if (!mem_cgroup_sockets_enabled
)
5663 * Socket cloning can throw us here with sk_memcg already
5664 * filled. It won't however, necessarily happen from
5665 * process context. So the test for root memcg given
5666 * the current task's memcg won't help us in this case.
5668 * Respecting the original socket's memcg is a better
5669 * decision in this case.
5672 BUG_ON(mem_cgroup_is_root(sk
->sk_memcg
));
5673 css_get(&sk
->sk_memcg
->css
);
5678 memcg
= mem_cgroup_from_task(current
);
5679 if (memcg
== root_mem_cgroup
)
5681 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
5683 if (css_tryget_online(&memcg
->css
))
5684 sk
->sk_memcg
= memcg
;
5689 void mem_cgroup_sk_free(struct sock
*sk
)
5692 css_put(&sk
->sk_memcg
->css
);
5696 * mem_cgroup_charge_skmem - charge socket memory
5697 * @memcg: memcg to charge
5698 * @nr_pages: number of pages to charge
5700 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
5701 * @memcg's configured limit, %false if the charge had to be forced.
5703 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5705 gfp_t gfp_mask
= GFP_KERNEL
;
5707 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5708 struct page_counter
*fail
;
5710 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
5711 memcg
->tcpmem_pressure
= 0;
5714 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
5715 memcg
->tcpmem_pressure
= 1;
5719 /* Don't block in the packet receive path */
5721 gfp_mask
= GFP_NOWAIT
;
5723 this_cpu_add(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5725 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
5728 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
5733 * mem_cgroup_uncharge_skmem - uncharge socket memory
5734 * @memcg - memcg to uncharge
5735 * @nr_pages - number of pages to uncharge
5737 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5739 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5740 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
5744 this_cpu_sub(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5746 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5747 css_put_many(&memcg
->css
, nr_pages
);
5750 static int __init
cgroup_memory(char *s
)
5754 while ((token
= strsep(&s
, ",")) != NULL
) {
5757 if (!strcmp(token
, "nosocket"))
5758 cgroup_memory_nosocket
= true;
5759 if (!strcmp(token
, "nokmem"))
5760 cgroup_memory_nokmem
= true;
5764 __setup("cgroup.memory=", cgroup_memory
);
5767 * subsys_initcall() for memory controller.
5769 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
5770 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
5771 * basically everything that doesn't depend on a specific mem_cgroup structure
5772 * should be initialized from here.
5774 static int __init
mem_cgroup_init(void)
5780 * Kmem cache creation is mostly done with the slab_mutex held,
5781 * so use a workqueue with limited concurrency to avoid stalling
5782 * all worker threads in case lots of cgroups are created and
5783 * destroyed simultaneously.
5785 memcg_kmem_cache_wq
= alloc_workqueue("memcg_kmem_cache", 0, 1);
5786 BUG_ON(!memcg_kmem_cache_wq
);
5789 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
5790 memcg_hotplug_cpu_dead
);
5792 for_each_possible_cpu(cpu
)
5793 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
5796 for_each_node(node
) {
5797 struct mem_cgroup_tree_per_node
*rtpn
;
5799 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
5800 node_online(node
) ? node
: NUMA_NO_NODE
);
5802 rtpn
->rb_root
= RB_ROOT
;
5803 spin_lock_init(&rtpn
->lock
);
5804 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
5809 subsys_initcall(mem_cgroup_init
);
5811 #ifdef CONFIG_MEMCG_SWAP
5812 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
5814 while (!atomic_inc_not_zero(&memcg
->id
.ref
)) {
5816 * The root cgroup cannot be destroyed, so it's refcount must
5819 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
5823 memcg
= parent_mem_cgroup(memcg
);
5825 memcg
= root_mem_cgroup
;
5831 * mem_cgroup_swapout - transfer a memsw charge to swap
5832 * @page: page whose memsw charge to transfer
5833 * @entry: swap entry to move the charge to
5835 * Transfer the memsw charge of @page to @entry.
5837 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
5839 struct mem_cgroup
*memcg
, *swap_memcg
;
5840 unsigned short oldid
;
5842 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5843 VM_BUG_ON_PAGE(page_count(page
), page
);
5845 if (!do_memsw_account())
5848 memcg
= page
->mem_cgroup
;
5850 /* Readahead page, never charged */
5855 * In case the memcg owning these pages has been offlined and doesn't
5856 * have an ID allocated to it anymore, charge the closest online
5857 * ancestor for the swap instead and transfer the memory+swap charge.
5859 swap_memcg
= mem_cgroup_id_get_online(memcg
);
5860 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
));
5861 VM_BUG_ON_PAGE(oldid
, page
);
5862 mem_cgroup_swap_statistics(swap_memcg
, true);
5864 page
->mem_cgroup
= NULL
;
5866 if (!mem_cgroup_is_root(memcg
))
5867 page_counter_uncharge(&memcg
->memory
, 1);
5869 if (memcg
!= swap_memcg
) {
5870 if (!mem_cgroup_is_root(swap_memcg
))
5871 page_counter_charge(&swap_memcg
->memsw
, 1);
5872 page_counter_uncharge(&memcg
->memsw
, 1);
5876 * Interrupts should be disabled here because the caller holds the
5877 * mapping->tree_lock lock which is taken with interrupts-off. It is
5878 * important here to have the interrupts disabled because it is the
5879 * only synchronisation we have for udpating the per-CPU variables.
5881 VM_BUG_ON(!irqs_disabled());
5882 mem_cgroup_charge_statistics(memcg
, page
, false, -1);
5883 memcg_check_events(memcg
, page
);
5885 if (!mem_cgroup_is_root(memcg
))
5886 css_put(&memcg
->css
);
5890 * mem_cgroup_try_charge_swap - try charging a swap entry
5891 * @page: page being added to swap
5892 * @entry: swap entry to charge
5894 * Try to charge @entry to the memcg that @page belongs to.
5896 * Returns 0 on success, -ENOMEM on failure.
5898 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
5900 struct mem_cgroup
*memcg
;
5901 struct page_counter
*counter
;
5902 unsigned short oldid
;
5904 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) || !do_swap_account
)
5907 memcg
= page
->mem_cgroup
;
5909 /* Readahead page, never charged */
5913 memcg
= mem_cgroup_id_get_online(memcg
);
5915 if (!mem_cgroup_is_root(memcg
) &&
5916 !page_counter_try_charge(&memcg
->swap
, 1, &counter
)) {
5917 mem_cgroup_id_put(memcg
);
5921 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
));
5922 VM_BUG_ON_PAGE(oldid
, page
);
5923 mem_cgroup_swap_statistics(memcg
, true);
5929 * mem_cgroup_uncharge_swap - uncharge a swap entry
5930 * @entry: swap entry to uncharge
5932 * Drop the swap charge associated with @entry.
5934 void mem_cgroup_uncharge_swap(swp_entry_t entry
)
5936 struct mem_cgroup
*memcg
;
5939 if (!do_swap_account
)
5942 id
= swap_cgroup_record(entry
, 0);
5944 memcg
= mem_cgroup_from_id(id
);
5946 if (!mem_cgroup_is_root(memcg
)) {
5947 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5948 page_counter_uncharge(&memcg
->swap
, 1);
5950 page_counter_uncharge(&memcg
->memsw
, 1);
5952 mem_cgroup_swap_statistics(memcg
, false);
5953 mem_cgroup_id_put(memcg
);
5958 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
5960 long nr_swap_pages
= get_nr_swap_pages();
5962 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5963 return nr_swap_pages
;
5964 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
5965 nr_swap_pages
= min_t(long, nr_swap_pages
,
5966 READ_ONCE(memcg
->swap
.limit
) -
5967 page_counter_read(&memcg
->swap
));
5968 return nr_swap_pages
;
5971 bool mem_cgroup_swap_full(struct page
*page
)
5973 struct mem_cgroup
*memcg
;
5975 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
5979 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5982 memcg
= page
->mem_cgroup
;
5986 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
5987 if (page_counter_read(&memcg
->swap
) * 2 >= memcg
->swap
.limit
)
5993 /* for remember boot option*/
5994 #ifdef CONFIG_MEMCG_SWAP_ENABLED
5995 static int really_do_swap_account __initdata
= 1;
5997 static int really_do_swap_account __initdata
;
6000 static int __init
enable_swap_account(char *s
)
6002 if (!strcmp(s
, "1"))
6003 really_do_swap_account
= 1;
6004 else if (!strcmp(s
, "0"))
6005 really_do_swap_account
= 0;
6008 __setup("swapaccount=", enable_swap_account
);
6010 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
6013 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6015 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
6018 static int swap_max_show(struct seq_file
*m
, void *v
)
6020 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
6021 unsigned long max
= READ_ONCE(memcg
->swap
.limit
);
6023 if (max
== PAGE_COUNTER_MAX
)
6024 seq_puts(m
, "max\n");
6026 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
6031 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
6032 char *buf
, size_t nbytes
, loff_t off
)
6034 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6038 buf
= strstrip(buf
);
6039 err
= page_counter_memparse(buf
, "max", &max
);
6043 mutex_lock(&memcg_limit_mutex
);
6044 err
= page_counter_limit(&memcg
->swap
, max
);
6045 mutex_unlock(&memcg_limit_mutex
);
6052 static struct cftype swap_files
[] = {
6054 .name
= "swap.current",
6055 .flags
= CFTYPE_NOT_ON_ROOT
,
6056 .read_u64
= swap_current_read
,
6060 .flags
= CFTYPE_NOT_ON_ROOT
,
6061 .seq_show
= swap_max_show
,
6062 .write
= swap_max_write
,
6067 static struct cftype memsw_cgroup_files
[] = {
6069 .name
= "memsw.usage_in_bytes",
6070 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6071 .read_u64
= mem_cgroup_read_u64
,
6074 .name
= "memsw.max_usage_in_bytes",
6075 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6076 .write
= mem_cgroup_reset
,
6077 .read_u64
= mem_cgroup_read_u64
,
6080 .name
= "memsw.limit_in_bytes",
6081 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6082 .write
= mem_cgroup_write
,
6083 .read_u64
= mem_cgroup_read_u64
,
6086 .name
= "memsw.failcnt",
6087 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6088 .write
= mem_cgroup_reset
,
6089 .read_u64
= mem_cgroup_read_u64
,
6091 { }, /* terminate */
6094 static int __init
mem_cgroup_swap_init(void)
6096 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6097 do_swap_account
= 1;
6098 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
,
6100 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
,
6101 memsw_cgroup_files
));
6105 subsys_initcall(mem_cgroup_swap_init
);
6107 #endif /* CONFIG_MEMCG_SWAP */