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/sched/mm.h>
39 #include <linux/shmem_fs.h>
40 #include <linux/hugetlb.h>
41 #include <linux/pagemap.h>
42 #include <linux/smp.h>
43 #include <linux/page-flags.h>
44 #include <linux/backing-dev.h>
45 #include <linux/bit_spinlock.h>
46 #include <linux/rcupdate.h>
47 #include <linux/limits.h>
48 #include <linux/export.h>
49 #include <linux/mutex.h>
50 #include <linux/rbtree.h>
51 #include <linux/slab.h>
52 #include <linux/swap.h>
53 #include <linux/swapops.h>
54 #include <linux/spinlock.h>
55 #include <linux/eventfd.h>
56 #include <linux/poll.h>
57 #include <linux/sort.h>
59 #include <linux/seq_file.h>
60 #include <linux/vmpressure.h>
61 #include <linux/mm_inline.h>
62 #include <linux/swap_cgroup.h>
63 #include <linux/cpu.h>
64 #include <linux/oom.h>
65 #include <linux/lockdep.h>
66 #include <linux/file.h>
67 #include <linux/tracehook.h>
73 #include <linux/uaccess.h>
75 #include <trace/events/vmscan.h>
77 struct cgroup_subsys memory_cgrp_subsys __read_mostly
;
78 EXPORT_SYMBOL(memory_cgrp_subsys
);
80 struct mem_cgroup
*root_mem_cgroup __read_mostly
;
82 #define MEM_CGROUP_RECLAIM_RETRIES 5
84 /* Socket memory accounting disabled? */
85 static bool cgroup_memory_nosocket
;
87 /* Kernel memory accounting disabled? */
88 static bool cgroup_memory_nokmem
;
90 /* Whether the swap controller is active */
91 #ifdef CONFIG_MEMCG_SWAP
92 int do_swap_account __read_mostly
;
94 #define do_swap_account 0
97 /* Whether legacy memory+swap accounting is active */
98 static bool do_memsw_account(void)
100 return !cgroup_subsys_on_dfl(memory_cgrp_subsys
) && do_swap_account
;
103 static const char * const mem_cgroup_stat_names
[] = {
113 static const char * const mem_cgroup_events_names
[] = {
120 static const char * const mem_cgroup_lru_names
[] = {
128 #define THRESHOLDS_EVENTS_TARGET 128
129 #define SOFTLIMIT_EVENTS_TARGET 1024
130 #define NUMAINFO_EVENTS_TARGET 1024
133 * Cgroups above their limits are maintained in a RB-Tree, independent of
134 * their hierarchy representation
137 struct mem_cgroup_tree_per_node
{
138 struct rb_root rb_root
;
142 struct mem_cgroup_tree
{
143 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
146 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
149 struct mem_cgroup_eventfd_list
{
150 struct list_head list
;
151 struct eventfd_ctx
*eventfd
;
155 * cgroup_event represents events which userspace want to receive.
157 struct mem_cgroup_event
{
159 * memcg which the event belongs to.
161 struct mem_cgroup
*memcg
;
163 * eventfd to signal userspace about the event.
165 struct eventfd_ctx
*eventfd
;
167 * Each of these stored in a list by the cgroup.
169 struct list_head list
;
171 * register_event() callback will be used to add new userspace
172 * waiter for changes related to this event. Use eventfd_signal()
173 * on eventfd to send notification to userspace.
175 int (*register_event
)(struct mem_cgroup
*memcg
,
176 struct eventfd_ctx
*eventfd
, const char *args
);
178 * unregister_event() callback will be called when userspace closes
179 * the eventfd or on cgroup removing. This callback must be set,
180 * if you want provide notification functionality.
182 void (*unregister_event
)(struct mem_cgroup
*memcg
,
183 struct eventfd_ctx
*eventfd
);
185 * All fields below needed to unregister event when
186 * userspace closes eventfd.
189 wait_queue_head_t
*wqh
;
191 struct work_struct remove
;
194 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
195 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
197 /* Stuffs for move charges at task migration. */
199 * Types of charges to be moved.
201 #define MOVE_ANON 0x1U
202 #define MOVE_FILE 0x2U
203 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
205 /* "mc" and its members are protected by cgroup_mutex */
206 static struct move_charge_struct
{
207 spinlock_t lock
; /* for from, to */
208 struct mm_struct
*mm
;
209 struct mem_cgroup
*from
;
210 struct mem_cgroup
*to
;
212 unsigned long precharge
;
213 unsigned long moved_charge
;
214 unsigned long moved_swap
;
215 struct task_struct
*moving_task
; /* a task moving charges */
216 wait_queue_head_t waitq
; /* a waitq for other context */
218 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
219 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
223 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
224 * limit reclaim to prevent infinite loops, if they ever occur.
226 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
227 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
230 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
231 MEM_CGROUP_CHARGE_TYPE_ANON
,
232 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
233 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
237 /* for encoding cft->private value on file */
246 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
247 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
248 #define MEMFILE_ATTR(val) ((val) & 0xffff)
249 /* Used for OOM nofiier */
250 #define OOM_CONTROL (0)
252 /* Some nice accessors for the vmpressure. */
253 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
256 memcg
= root_mem_cgroup
;
257 return &memcg
->vmpressure
;
260 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
262 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
265 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
267 return (memcg
== root_mem_cgroup
);
272 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
273 * The main reason for not using cgroup id for this:
274 * this works better in sparse environments, where we have a lot of memcgs,
275 * but only a few kmem-limited. Or also, if we have, for instance, 200
276 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
277 * 200 entry array for that.
279 * The current size of the caches array is stored in memcg_nr_cache_ids. It
280 * will double each time we have to increase it.
282 static DEFINE_IDA(memcg_cache_ida
);
283 int memcg_nr_cache_ids
;
285 /* Protects memcg_nr_cache_ids */
286 static DECLARE_RWSEM(memcg_cache_ids_sem
);
288 void memcg_get_cache_ids(void)
290 down_read(&memcg_cache_ids_sem
);
293 void memcg_put_cache_ids(void)
295 up_read(&memcg_cache_ids_sem
);
299 * MIN_SIZE is different than 1, because we would like to avoid going through
300 * the alloc/free process all the time. In a small machine, 4 kmem-limited
301 * cgroups is a reasonable guess. In the future, it could be a parameter or
302 * tunable, but that is strictly not necessary.
304 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
305 * this constant directly from cgroup, but it is understandable that this is
306 * better kept as an internal representation in cgroup.c. In any case, the
307 * cgrp_id space is not getting any smaller, and we don't have to necessarily
308 * increase ours as well if it increases.
310 #define MEMCG_CACHES_MIN_SIZE 4
311 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
314 * A lot of the calls to the cache allocation functions are expected to be
315 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
316 * conditional to this static branch, we'll have to allow modules that does
317 * kmem_cache_alloc and the such to see this symbol as well
319 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
320 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
322 struct workqueue_struct
*memcg_kmem_cache_wq
;
324 #endif /* !CONFIG_SLOB */
327 * mem_cgroup_css_from_page - css of the memcg associated with a page
328 * @page: page of interest
330 * If memcg is bound to the default hierarchy, css of the memcg associated
331 * with @page is returned. The returned css remains associated with @page
332 * until it is released.
334 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
337 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
339 struct mem_cgroup
*memcg
;
341 memcg
= page
->mem_cgroup
;
343 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
344 memcg
= root_mem_cgroup
;
350 * page_cgroup_ino - return inode number of the memcg a page is charged to
353 * Look up the closest online ancestor of the memory cgroup @page is charged to
354 * and return its inode number or 0 if @page is not charged to any cgroup. It
355 * is safe to call this function without holding a reference to @page.
357 * Note, this function is inherently racy, because there is nothing to prevent
358 * the cgroup inode from getting torn down and potentially reallocated a moment
359 * after page_cgroup_ino() returns, so it only should be used by callers that
360 * do not care (such as procfs interfaces).
362 ino_t
page_cgroup_ino(struct page
*page
)
364 struct mem_cgroup
*memcg
;
365 unsigned long ino
= 0;
368 memcg
= READ_ONCE(page
->mem_cgroup
);
369 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
370 memcg
= parent_mem_cgroup(memcg
);
372 ino
= cgroup_ino(memcg
->css
.cgroup
);
377 static struct mem_cgroup_per_node
*
378 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
380 int nid
= page_to_nid(page
);
382 return memcg
->nodeinfo
[nid
];
385 static struct mem_cgroup_tree_per_node
*
386 soft_limit_tree_node(int nid
)
388 return soft_limit_tree
.rb_tree_per_node
[nid
];
391 static struct mem_cgroup_tree_per_node
*
392 soft_limit_tree_from_page(struct page
*page
)
394 int nid
= page_to_nid(page
);
396 return soft_limit_tree
.rb_tree_per_node
[nid
];
399 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
400 struct mem_cgroup_tree_per_node
*mctz
,
401 unsigned long new_usage_in_excess
)
403 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
404 struct rb_node
*parent
= NULL
;
405 struct mem_cgroup_per_node
*mz_node
;
410 mz
->usage_in_excess
= new_usage_in_excess
;
411 if (!mz
->usage_in_excess
)
415 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
417 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
420 * We can't avoid mem cgroups that are over their soft
421 * limit by the same amount
423 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
426 rb_link_node(&mz
->tree_node
, parent
, p
);
427 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
431 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
432 struct mem_cgroup_tree_per_node
*mctz
)
436 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
440 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
441 struct mem_cgroup_tree_per_node
*mctz
)
445 spin_lock_irqsave(&mctz
->lock
, flags
);
446 __mem_cgroup_remove_exceeded(mz
, mctz
);
447 spin_unlock_irqrestore(&mctz
->lock
, flags
);
450 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
452 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
453 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
454 unsigned long excess
= 0;
456 if (nr_pages
> soft_limit
)
457 excess
= nr_pages
- soft_limit
;
462 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
464 unsigned long excess
;
465 struct mem_cgroup_per_node
*mz
;
466 struct mem_cgroup_tree_per_node
*mctz
;
468 mctz
= soft_limit_tree_from_page(page
);
470 * Necessary to update all ancestors when hierarchy is used.
471 * because their event counter is not touched.
473 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
474 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
475 excess
= soft_limit_excess(memcg
);
477 * We have to update the tree if mz is on RB-tree or
478 * mem is over its softlimit.
480 if (excess
|| mz
->on_tree
) {
483 spin_lock_irqsave(&mctz
->lock
, flags
);
484 /* if on-tree, remove it */
486 __mem_cgroup_remove_exceeded(mz
, mctz
);
488 * Insert again. mz->usage_in_excess will be updated.
489 * If excess is 0, no tree ops.
491 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
492 spin_unlock_irqrestore(&mctz
->lock
, flags
);
497 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
499 struct mem_cgroup_tree_per_node
*mctz
;
500 struct mem_cgroup_per_node
*mz
;
504 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
505 mctz
= soft_limit_tree_node(nid
);
506 mem_cgroup_remove_exceeded(mz
, mctz
);
510 static struct mem_cgroup_per_node
*
511 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
513 struct rb_node
*rightmost
= NULL
;
514 struct mem_cgroup_per_node
*mz
;
518 rightmost
= rb_last(&mctz
->rb_root
);
520 goto done
; /* Nothing to reclaim from */
522 mz
= rb_entry(rightmost
, struct mem_cgroup_per_node
, tree_node
);
524 * Remove the node now but someone else can add it back,
525 * we will to add it back at the end of reclaim to its correct
526 * position in the tree.
528 __mem_cgroup_remove_exceeded(mz
, mctz
);
529 if (!soft_limit_excess(mz
->memcg
) ||
530 !css_tryget_online(&mz
->memcg
->css
))
536 static struct mem_cgroup_per_node
*
537 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
539 struct mem_cgroup_per_node
*mz
;
541 spin_lock_irq(&mctz
->lock
);
542 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
543 spin_unlock_irq(&mctz
->lock
);
548 * Return page count for single (non recursive) @memcg.
550 * Implementation Note: reading percpu statistics for memcg.
552 * Both of vmstat[] and percpu_counter has threshold and do periodic
553 * synchronization to implement "quick" read. There are trade-off between
554 * reading cost and precision of value. Then, we may have a chance to implement
555 * a periodic synchronization of counter in memcg's counter.
557 * But this _read() function is used for user interface now. The user accounts
558 * memory usage by memory cgroup and he _always_ requires exact value because
559 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
560 * have to visit all online cpus and make sum. So, for now, unnecessary
561 * synchronization is not implemented. (just implemented for cpu hotplug)
563 * If there are kernel internal actions which can make use of some not-exact
564 * value, and reading all cpu value can be performance bottleneck in some
565 * common workload, threshold and synchronization as vmstat[] should be
569 mem_cgroup_read_stat(struct mem_cgroup
*memcg
, enum mem_cgroup_stat_index idx
)
574 /* Per-cpu values can be negative, use a signed accumulator */
575 for_each_possible_cpu(cpu
)
576 val
+= per_cpu(memcg
->stat
->count
[idx
], cpu
);
578 * Summing races with updates, so val may be negative. Avoid exposing
579 * transient negative values.
586 static unsigned long mem_cgroup_read_events(struct mem_cgroup
*memcg
,
587 enum mem_cgroup_events_index idx
)
589 unsigned long val
= 0;
592 for_each_possible_cpu(cpu
)
593 val
+= per_cpu(memcg
->stat
->events
[idx
], cpu
);
597 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
599 bool compound
, int nr_pages
)
602 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
603 * counted as CACHE even if it's on ANON LRU.
606 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
],
609 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
],
613 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
614 __this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
618 /* pagein of a big page is an event. So, ignore page size */
620 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGIN
]);
622 __this_cpu_inc(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
]);
623 nr_pages
= -nr_pages
; /* for event */
626 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
629 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
630 int nid
, unsigned int lru_mask
)
632 struct lruvec
*lruvec
= mem_cgroup_lruvec(NODE_DATA(nid
), memcg
);
633 unsigned long nr
= 0;
636 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
639 if (!(BIT(lru
) & lru_mask
))
641 nr
+= mem_cgroup_get_lru_size(lruvec
, lru
);
646 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
647 unsigned int lru_mask
)
649 unsigned long nr
= 0;
652 for_each_node_state(nid
, N_MEMORY
)
653 nr
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
657 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
658 enum mem_cgroup_events_target target
)
660 unsigned long val
, next
;
662 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
663 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
664 /* from time_after() in jiffies.h */
665 if ((long)next
- (long)val
< 0) {
667 case MEM_CGROUP_TARGET_THRESH
:
668 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
670 case MEM_CGROUP_TARGET_SOFTLIMIT
:
671 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
673 case MEM_CGROUP_TARGET_NUMAINFO
:
674 next
= val
+ NUMAINFO_EVENTS_TARGET
;
679 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
686 * Check events in order.
689 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
691 /* threshold event is triggered in finer grain than soft limit */
692 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
693 MEM_CGROUP_TARGET_THRESH
))) {
695 bool do_numainfo __maybe_unused
;
697 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
698 MEM_CGROUP_TARGET_SOFTLIMIT
);
700 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
701 MEM_CGROUP_TARGET_NUMAINFO
);
703 mem_cgroup_threshold(memcg
);
704 if (unlikely(do_softlimit
))
705 mem_cgroup_update_tree(memcg
, page
);
707 if (unlikely(do_numainfo
))
708 atomic_inc(&memcg
->numainfo_events
);
713 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
716 * mm_update_next_owner() may clear mm->owner to NULL
717 * if it races with swapoff, page migration, etc.
718 * So this can be called with p == NULL.
723 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
725 EXPORT_SYMBOL(mem_cgroup_from_task
);
727 static struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
729 struct mem_cgroup
*memcg
= NULL
;
734 * Page cache insertions can happen withou an
735 * actual mm context, e.g. during disk probing
736 * on boot, loopback IO, acct() writes etc.
739 memcg
= root_mem_cgroup
;
741 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
742 if (unlikely(!memcg
))
743 memcg
= root_mem_cgroup
;
745 } while (!css_tryget_online(&memcg
->css
));
751 * mem_cgroup_iter - iterate over memory cgroup hierarchy
752 * @root: hierarchy root
753 * @prev: previously returned memcg, NULL on first invocation
754 * @reclaim: cookie for shared reclaim walks, NULL for full walks
756 * Returns references to children of the hierarchy below @root, or
757 * @root itself, or %NULL after a full round-trip.
759 * Caller must pass the return value in @prev on subsequent
760 * invocations for reference counting, or use mem_cgroup_iter_break()
761 * to cancel a hierarchy walk before the round-trip is complete.
763 * Reclaimers can specify a zone and a priority level in @reclaim to
764 * divide up the memcgs in the hierarchy among all concurrent
765 * reclaimers operating on the same zone and priority.
767 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
768 struct mem_cgroup
*prev
,
769 struct mem_cgroup_reclaim_cookie
*reclaim
)
771 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
772 struct cgroup_subsys_state
*css
= NULL
;
773 struct mem_cgroup
*memcg
= NULL
;
774 struct mem_cgroup
*pos
= NULL
;
776 if (mem_cgroup_disabled())
780 root
= root_mem_cgroup
;
782 if (prev
&& !reclaim
)
785 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
794 struct mem_cgroup_per_node
*mz
;
796 mz
= mem_cgroup_nodeinfo(root
, reclaim
->pgdat
->node_id
);
797 iter
= &mz
->iter
[reclaim
->priority
];
799 if (prev
&& reclaim
->generation
!= iter
->generation
)
803 pos
= READ_ONCE(iter
->position
);
804 if (!pos
|| css_tryget(&pos
->css
))
807 * css reference reached zero, so iter->position will
808 * be cleared by ->css_released. However, we should not
809 * rely on this happening soon, because ->css_released
810 * is called from a work queue, and by busy-waiting we
811 * might block it. So we clear iter->position right
814 (void)cmpxchg(&iter
->position
, pos
, NULL
);
822 css
= css_next_descendant_pre(css
, &root
->css
);
825 * Reclaimers share the hierarchy walk, and a
826 * new one might jump in right at the end of
827 * the hierarchy - make sure they see at least
828 * one group and restart from the beginning.
836 * Verify the css and acquire a reference. The root
837 * is provided by the caller, so we know it's alive
838 * and kicking, and don't take an extra reference.
840 memcg
= mem_cgroup_from_css(css
);
842 if (css
== &root
->css
)
853 * The position could have already been updated by a competing
854 * thread, so check that the value hasn't changed since we read
855 * it to avoid reclaiming from the same cgroup twice.
857 (void)cmpxchg(&iter
->position
, pos
, memcg
);
865 reclaim
->generation
= iter
->generation
;
871 if (prev
&& prev
!= root
)
878 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
879 * @root: hierarchy root
880 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
882 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
883 struct mem_cgroup
*prev
)
886 root
= root_mem_cgroup
;
887 if (prev
&& prev
!= root
)
891 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
893 struct mem_cgroup
*memcg
= dead_memcg
;
894 struct mem_cgroup_reclaim_iter
*iter
;
895 struct mem_cgroup_per_node
*mz
;
899 while ((memcg
= parent_mem_cgroup(memcg
))) {
901 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
902 for (i
= 0; i
<= DEF_PRIORITY
; i
++) {
904 cmpxchg(&iter
->position
,
912 * Iteration constructs for visiting all cgroups (under a tree). If
913 * loops are exited prematurely (break), mem_cgroup_iter_break() must
914 * be used for reference counting.
916 #define for_each_mem_cgroup_tree(iter, root) \
917 for (iter = mem_cgroup_iter(root, NULL, NULL); \
919 iter = mem_cgroup_iter(root, iter, NULL))
921 #define for_each_mem_cgroup(iter) \
922 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
924 iter = mem_cgroup_iter(NULL, iter, NULL))
927 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
928 * @memcg: hierarchy root
929 * @fn: function to call for each task
930 * @arg: argument passed to @fn
932 * This function iterates over tasks attached to @memcg or to any of its
933 * descendants and calls @fn for each task. If @fn returns a non-zero
934 * value, the function breaks the iteration loop and returns the value.
935 * Otherwise, it will iterate over all tasks and return 0.
937 * This function must not be called for the root memory cgroup.
939 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
940 int (*fn
)(struct task_struct
*, void *), void *arg
)
942 struct mem_cgroup
*iter
;
945 BUG_ON(memcg
== root_mem_cgroup
);
947 for_each_mem_cgroup_tree(iter
, memcg
) {
948 struct css_task_iter it
;
949 struct task_struct
*task
;
951 css_task_iter_start(&iter
->css
, &it
);
952 while (!ret
&& (task
= css_task_iter_next(&it
)))
954 css_task_iter_end(&it
);
956 mem_cgroup_iter_break(memcg
, iter
);
964 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
966 * @zone: zone of the page
968 * This function is only safe when following the LRU page isolation
969 * and putback protocol: the LRU lock must be held, and the page must
970 * either be PageLRU() or the caller must have isolated/allocated it.
972 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct pglist_data
*pgdat
)
974 struct mem_cgroup_per_node
*mz
;
975 struct mem_cgroup
*memcg
;
976 struct lruvec
*lruvec
;
978 if (mem_cgroup_disabled()) {
979 lruvec
= &pgdat
->lruvec
;
983 memcg
= page
->mem_cgroup
;
985 * Swapcache readahead pages are added to the LRU - and
986 * possibly migrated - before they are charged.
989 memcg
= root_mem_cgroup
;
991 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
992 lruvec
= &mz
->lruvec
;
995 * Since a node can be onlined after the mem_cgroup was created,
996 * we have to be prepared to initialize lruvec->zone here;
997 * and if offlined then reonlined, we need to reinitialize it.
999 if (unlikely(lruvec
->pgdat
!= pgdat
))
1000 lruvec
->pgdat
= pgdat
;
1005 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1006 * @lruvec: mem_cgroup per zone lru vector
1007 * @lru: index of lru list the page is sitting on
1008 * @zid: zone id of the accounted pages
1009 * @nr_pages: positive when adding or negative when removing
1011 * This function must be called under lru_lock, just before a page is added
1012 * to or just after a page is removed from an lru list (that ordering being
1013 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1015 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1016 int zid
, int nr_pages
)
1018 struct mem_cgroup_per_node
*mz
;
1019 unsigned long *lru_size
;
1022 if (mem_cgroup_disabled())
1025 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1026 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1029 *lru_size
+= nr_pages
;
1032 if (WARN_ONCE(size
< 0,
1033 "%s(%p, %d, %d): lru_size %ld\n",
1034 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1040 *lru_size
+= nr_pages
;
1043 bool task_in_mem_cgroup(struct task_struct
*task
, struct mem_cgroup
*memcg
)
1045 struct mem_cgroup
*task_memcg
;
1046 struct task_struct
*p
;
1049 p
= find_lock_task_mm(task
);
1051 task_memcg
= get_mem_cgroup_from_mm(p
->mm
);
1055 * All threads may have already detached their mm's, but the oom
1056 * killer still needs to detect if they have already been oom
1057 * killed to prevent needlessly killing additional tasks.
1060 task_memcg
= mem_cgroup_from_task(task
);
1061 css_get(&task_memcg
->css
);
1064 ret
= mem_cgroup_is_descendant(task_memcg
, memcg
);
1065 css_put(&task_memcg
->css
);
1070 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1071 * @memcg: the memory cgroup
1073 * Returns the maximum amount of memory @mem can be charged with, in
1076 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1078 unsigned long margin
= 0;
1079 unsigned long count
;
1080 unsigned long limit
;
1082 count
= page_counter_read(&memcg
->memory
);
1083 limit
= READ_ONCE(memcg
->memory
.limit
);
1085 margin
= limit
- count
;
1087 if (do_memsw_account()) {
1088 count
= page_counter_read(&memcg
->memsw
);
1089 limit
= READ_ONCE(memcg
->memsw
.limit
);
1091 margin
= min(margin
, limit
- count
);
1100 * A routine for checking "mem" is under move_account() or not.
1102 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1103 * moving cgroups. This is for waiting at high-memory pressure
1106 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1108 struct mem_cgroup
*from
;
1109 struct mem_cgroup
*to
;
1112 * Unlike task_move routines, we access mc.to, mc.from not under
1113 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1115 spin_lock(&mc
.lock
);
1121 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1122 mem_cgroup_is_descendant(to
, memcg
);
1124 spin_unlock(&mc
.lock
);
1128 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1130 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1131 if (mem_cgroup_under_move(memcg
)) {
1133 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1134 /* moving charge context might have finished. */
1137 finish_wait(&mc
.waitq
, &wait
);
1144 #define K(x) ((x) << (PAGE_SHIFT-10))
1146 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1147 * @memcg: The memory cgroup that went over limit
1148 * @p: Task that is going to be killed
1150 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1153 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1155 struct mem_cgroup
*iter
;
1161 pr_info("Task in ");
1162 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1163 pr_cont(" killed as a result of limit of ");
1165 pr_info("Memory limit reached of cgroup ");
1168 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1173 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1174 K((u64
)page_counter_read(&memcg
->memory
)),
1175 K((u64
)memcg
->memory
.limit
), memcg
->memory
.failcnt
);
1176 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1177 K((u64
)page_counter_read(&memcg
->memsw
)),
1178 K((u64
)memcg
->memsw
.limit
), memcg
->memsw
.failcnt
);
1179 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1180 K((u64
)page_counter_read(&memcg
->kmem
)),
1181 K((u64
)memcg
->kmem
.limit
), memcg
->kmem
.failcnt
);
1183 for_each_mem_cgroup_tree(iter
, memcg
) {
1184 pr_info("Memory cgroup stats for ");
1185 pr_cont_cgroup_path(iter
->css
.cgroup
);
1188 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
1189 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_swap_account
)
1191 pr_cont(" %s:%luKB", mem_cgroup_stat_names
[i
],
1192 K(mem_cgroup_read_stat(iter
, i
)));
1195 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1196 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1197 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1204 * This function returns the number of memcg under hierarchy tree. Returns
1205 * 1(self count) if no children.
1207 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1210 struct mem_cgroup
*iter
;
1212 for_each_mem_cgroup_tree(iter
, memcg
)
1218 * Return the memory (and swap, if configured) limit for a memcg.
1220 unsigned long mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1222 unsigned long limit
;
1224 limit
= memcg
->memory
.limit
;
1225 if (mem_cgroup_swappiness(memcg
)) {
1226 unsigned long memsw_limit
;
1227 unsigned long swap_limit
;
1229 memsw_limit
= memcg
->memsw
.limit
;
1230 swap_limit
= memcg
->swap
.limit
;
1231 swap_limit
= min(swap_limit
, (unsigned long)total_swap_pages
);
1232 limit
= min(limit
+ swap_limit
, memsw_limit
);
1237 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1240 struct oom_control oc
= {
1244 .gfp_mask
= gfp_mask
,
1249 mutex_lock(&oom_lock
);
1250 ret
= out_of_memory(&oc
);
1251 mutex_unlock(&oom_lock
);
1255 #if MAX_NUMNODES > 1
1258 * test_mem_cgroup_node_reclaimable
1259 * @memcg: the target memcg
1260 * @nid: the node ID to be checked.
1261 * @noswap : specify true here if the user wants flle only information.
1263 * This function returns whether the specified memcg contains any
1264 * reclaimable pages on a node. Returns true if there are any reclaimable
1265 * pages in the node.
1267 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1268 int nid
, bool noswap
)
1270 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1272 if (noswap
|| !total_swap_pages
)
1274 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1281 * Always updating the nodemask is not very good - even if we have an empty
1282 * list or the wrong list here, we can start from some node and traverse all
1283 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1286 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1290 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1291 * pagein/pageout changes since the last update.
1293 if (!atomic_read(&memcg
->numainfo_events
))
1295 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1298 /* make a nodemask where this memcg uses memory from */
1299 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1301 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1303 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1304 node_clear(nid
, memcg
->scan_nodes
);
1307 atomic_set(&memcg
->numainfo_events
, 0);
1308 atomic_set(&memcg
->numainfo_updating
, 0);
1312 * Selecting a node where we start reclaim from. Because what we need is just
1313 * reducing usage counter, start from anywhere is O,K. Considering
1314 * memory reclaim from current node, there are pros. and cons.
1316 * Freeing memory from current node means freeing memory from a node which
1317 * we'll use or we've used. So, it may make LRU bad. And if several threads
1318 * hit limits, it will see a contention on a node. But freeing from remote
1319 * node means more costs for memory reclaim because of memory latency.
1321 * Now, we use round-robin. Better algorithm is welcomed.
1323 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1327 mem_cgroup_may_update_nodemask(memcg
);
1328 node
= memcg
->last_scanned_node
;
1330 node
= next_node_in(node
, memcg
->scan_nodes
);
1332 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1333 * last time it really checked all the LRUs due to rate limiting.
1334 * Fallback to the current node in that case for simplicity.
1336 if (unlikely(node
== MAX_NUMNODES
))
1337 node
= numa_node_id();
1339 memcg
->last_scanned_node
= node
;
1343 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1349 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1352 unsigned long *total_scanned
)
1354 struct mem_cgroup
*victim
= NULL
;
1357 unsigned long excess
;
1358 unsigned long nr_scanned
;
1359 struct mem_cgroup_reclaim_cookie reclaim
= {
1364 excess
= soft_limit_excess(root_memcg
);
1367 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1372 * If we have not been able to reclaim
1373 * anything, it might because there are
1374 * no reclaimable pages under this hierarchy
1379 * We want to do more targeted reclaim.
1380 * excess >> 2 is not to excessive so as to
1381 * reclaim too much, nor too less that we keep
1382 * coming back to reclaim from this cgroup
1384 if (total
>= (excess
>> 2) ||
1385 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1390 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1391 pgdat
, &nr_scanned
);
1392 *total_scanned
+= nr_scanned
;
1393 if (!soft_limit_excess(root_memcg
))
1396 mem_cgroup_iter_break(root_memcg
, victim
);
1400 #ifdef CONFIG_LOCKDEP
1401 static struct lockdep_map memcg_oom_lock_dep_map
= {
1402 .name
= "memcg_oom_lock",
1406 static DEFINE_SPINLOCK(memcg_oom_lock
);
1409 * Check OOM-Killer is already running under our hierarchy.
1410 * If someone is running, return false.
1412 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1414 struct mem_cgroup
*iter
, *failed
= NULL
;
1416 spin_lock(&memcg_oom_lock
);
1418 for_each_mem_cgroup_tree(iter
, memcg
) {
1419 if (iter
->oom_lock
) {
1421 * this subtree of our hierarchy is already locked
1422 * so we cannot give a lock.
1425 mem_cgroup_iter_break(memcg
, iter
);
1428 iter
->oom_lock
= true;
1433 * OK, we failed to lock the whole subtree so we have
1434 * to clean up what we set up to the failing subtree
1436 for_each_mem_cgroup_tree(iter
, memcg
) {
1437 if (iter
== failed
) {
1438 mem_cgroup_iter_break(memcg
, iter
);
1441 iter
->oom_lock
= false;
1444 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1446 spin_unlock(&memcg_oom_lock
);
1451 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1453 struct mem_cgroup
*iter
;
1455 spin_lock(&memcg_oom_lock
);
1456 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
1457 for_each_mem_cgroup_tree(iter
, memcg
)
1458 iter
->oom_lock
= false;
1459 spin_unlock(&memcg_oom_lock
);
1462 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1464 struct mem_cgroup
*iter
;
1466 spin_lock(&memcg_oom_lock
);
1467 for_each_mem_cgroup_tree(iter
, memcg
)
1469 spin_unlock(&memcg_oom_lock
);
1472 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1474 struct mem_cgroup
*iter
;
1477 * When a new child is created while the hierarchy is under oom,
1478 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1480 spin_lock(&memcg_oom_lock
);
1481 for_each_mem_cgroup_tree(iter
, memcg
)
1482 if (iter
->under_oom
> 0)
1484 spin_unlock(&memcg_oom_lock
);
1487 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1489 struct oom_wait_info
{
1490 struct mem_cgroup
*memcg
;
1494 static int memcg_oom_wake_function(wait_queue_t
*wait
,
1495 unsigned mode
, int sync
, void *arg
)
1497 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1498 struct mem_cgroup
*oom_wait_memcg
;
1499 struct oom_wait_info
*oom_wait_info
;
1501 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1502 oom_wait_memcg
= oom_wait_info
->memcg
;
1504 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1505 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1507 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1510 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1513 * For the following lockless ->under_oom test, the only required
1514 * guarantee is that it must see the state asserted by an OOM when
1515 * this function is called as a result of userland actions
1516 * triggered by the notification of the OOM. This is trivially
1517 * achieved by invoking mem_cgroup_mark_under_oom() before
1518 * triggering notification.
1520 if (memcg
&& memcg
->under_oom
)
1521 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1524 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1526 if (!current
->memcg_may_oom
)
1529 * We are in the middle of the charge context here, so we
1530 * don't want to block when potentially sitting on a callstack
1531 * that holds all kinds of filesystem and mm locks.
1533 * Also, the caller may handle a failed allocation gracefully
1534 * (like optional page cache readahead) and so an OOM killer
1535 * invocation might not even be necessary.
1537 * That's why we don't do anything here except remember the
1538 * OOM context and then deal with it at the end of the page
1539 * fault when the stack is unwound, the locks are released,
1540 * and when we know whether the fault was overall successful.
1542 css_get(&memcg
->css
);
1543 current
->memcg_in_oom
= memcg
;
1544 current
->memcg_oom_gfp_mask
= mask
;
1545 current
->memcg_oom_order
= order
;
1549 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1550 * @handle: actually kill/wait or just clean up the OOM state
1552 * This has to be called at the end of a page fault if the memcg OOM
1553 * handler was enabled.
1555 * Memcg supports userspace OOM handling where failed allocations must
1556 * sleep on a waitqueue until the userspace task resolves the
1557 * situation. Sleeping directly in the charge context with all kinds
1558 * of locks held is not a good idea, instead we remember an OOM state
1559 * in the task and mem_cgroup_oom_synchronize() has to be called at
1560 * the end of the page fault to complete the OOM handling.
1562 * Returns %true if an ongoing memcg OOM situation was detected and
1563 * completed, %false otherwise.
1565 bool mem_cgroup_oom_synchronize(bool handle
)
1567 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1568 struct oom_wait_info owait
;
1571 /* OOM is global, do not handle */
1578 owait
.memcg
= memcg
;
1579 owait
.wait
.flags
= 0;
1580 owait
.wait
.func
= memcg_oom_wake_function
;
1581 owait
.wait
.private = current
;
1582 INIT_LIST_HEAD(&owait
.wait
.task_list
);
1584 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1585 mem_cgroup_mark_under_oom(memcg
);
1587 locked
= mem_cgroup_oom_trylock(memcg
);
1590 mem_cgroup_oom_notify(memcg
);
1592 if (locked
&& !memcg
->oom_kill_disable
) {
1593 mem_cgroup_unmark_under_oom(memcg
);
1594 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1595 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1596 current
->memcg_oom_order
);
1599 mem_cgroup_unmark_under_oom(memcg
);
1600 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1604 mem_cgroup_oom_unlock(memcg
);
1606 * There is no guarantee that an OOM-lock contender
1607 * sees the wakeups triggered by the OOM kill
1608 * uncharges. Wake any sleepers explicitely.
1610 memcg_oom_recover(memcg
);
1613 current
->memcg_in_oom
= NULL
;
1614 css_put(&memcg
->css
);
1619 * lock_page_memcg - lock a page->mem_cgroup binding
1622 * This function protects unlocked LRU pages from being moved to
1623 * another cgroup and stabilizes their page->mem_cgroup binding.
1625 void lock_page_memcg(struct page
*page
)
1627 struct mem_cgroup
*memcg
;
1628 unsigned long flags
;
1631 * The RCU lock is held throughout the transaction. The fast
1632 * path can get away without acquiring the memcg->move_lock
1633 * because page moving starts with an RCU grace period.
1637 if (mem_cgroup_disabled())
1640 memcg
= page
->mem_cgroup
;
1641 if (unlikely(!memcg
))
1644 if (atomic_read(&memcg
->moving_account
) <= 0)
1647 spin_lock_irqsave(&memcg
->move_lock
, flags
);
1648 if (memcg
!= page
->mem_cgroup
) {
1649 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1654 * When charge migration first begins, we can have locked and
1655 * unlocked page stat updates happening concurrently. Track
1656 * the task who has the lock for unlock_page_memcg().
1658 memcg
->move_lock_task
= current
;
1659 memcg
->move_lock_flags
= flags
;
1663 EXPORT_SYMBOL(lock_page_memcg
);
1666 * unlock_page_memcg - unlock a page->mem_cgroup binding
1669 void unlock_page_memcg(struct page
*page
)
1671 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
1673 if (memcg
&& memcg
->move_lock_task
== current
) {
1674 unsigned long flags
= memcg
->move_lock_flags
;
1676 memcg
->move_lock_task
= NULL
;
1677 memcg
->move_lock_flags
= 0;
1679 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1684 EXPORT_SYMBOL(unlock_page_memcg
);
1687 * size of first charge trial. "32" comes from vmscan.c's magic value.
1688 * TODO: maybe necessary to use big numbers in big irons.
1690 #define CHARGE_BATCH 32U
1691 struct memcg_stock_pcp
{
1692 struct mem_cgroup
*cached
; /* this never be root cgroup */
1693 unsigned int nr_pages
;
1694 struct work_struct work
;
1695 unsigned long flags
;
1696 #define FLUSHING_CACHED_CHARGE 0
1698 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
1699 static DEFINE_MUTEX(percpu_charge_mutex
);
1702 * consume_stock: Try to consume stocked charge on this cpu.
1703 * @memcg: memcg to consume from.
1704 * @nr_pages: how many pages to charge.
1706 * The charges will only happen if @memcg matches the current cpu's memcg
1707 * stock, and at least @nr_pages are available in that stock. Failure to
1708 * service an allocation will refill the stock.
1710 * returns true if successful, false otherwise.
1712 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1714 struct memcg_stock_pcp
*stock
;
1715 unsigned long flags
;
1718 if (nr_pages
> CHARGE_BATCH
)
1721 local_irq_save(flags
);
1723 stock
= this_cpu_ptr(&memcg_stock
);
1724 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
1725 stock
->nr_pages
-= nr_pages
;
1729 local_irq_restore(flags
);
1735 * Returns stocks cached in percpu and reset cached information.
1737 static void drain_stock(struct memcg_stock_pcp
*stock
)
1739 struct mem_cgroup
*old
= stock
->cached
;
1741 if (stock
->nr_pages
) {
1742 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
1743 if (do_memsw_account())
1744 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
1745 css_put_many(&old
->css
, stock
->nr_pages
);
1746 stock
->nr_pages
= 0;
1748 stock
->cached
= NULL
;
1751 static void drain_local_stock(struct work_struct
*dummy
)
1753 struct memcg_stock_pcp
*stock
;
1754 unsigned long flags
;
1756 local_irq_save(flags
);
1758 stock
= this_cpu_ptr(&memcg_stock
);
1760 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
1762 local_irq_restore(flags
);
1766 * Cache charges(val) to local per_cpu area.
1767 * This will be consumed by consume_stock() function, later.
1769 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1771 struct memcg_stock_pcp
*stock
;
1772 unsigned long flags
;
1774 local_irq_save(flags
);
1776 stock
= this_cpu_ptr(&memcg_stock
);
1777 if (stock
->cached
!= memcg
) { /* reset if necessary */
1779 stock
->cached
= memcg
;
1781 stock
->nr_pages
+= nr_pages
;
1783 local_irq_restore(flags
);
1787 * Drains all per-CPU charge caches for given root_memcg resp. subtree
1788 * of the hierarchy under it.
1790 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
1794 /* If someone's already draining, avoid adding running more workers. */
1795 if (!mutex_trylock(&percpu_charge_mutex
))
1797 /* Notify other cpus that system-wide "drain" is running */
1800 for_each_online_cpu(cpu
) {
1801 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
1802 struct mem_cgroup
*memcg
;
1804 memcg
= stock
->cached
;
1805 if (!memcg
|| !stock
->nr_pages
)
1807 if (!mem_cgroup_is_descendant(memcg
, root_memcg
))
1809 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
1811 drain_local_stock(&stock
->work
);
1813 schedule_work_on(cpu
, &stock
->work
);
1818 mutex_unlock(&percpu_charge_mutex
);
1821 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
1823 struct memcg_stock_pcp
*stock
;
1825 stock
= &per_cpu(memcg_stock
, cpu
);
1830 static void reclaim_high(struct mem_cgroup
*memcg
,
1831 unsigned int nr_pages
,
1835 if (page_counter_read(&memcg
->memory
) <= memcg
->high
)
1837 mem_cgroup_events(memcg
, MEMCG_HIGH
, 1);
1838 try_to_free_mem_cgroup_pages(memcg
, nr_pages
, gfp_mask
, true);
1839 } while ((memcg
= parent_mem_cgroup(memcg
)));
1842 static void high_work_func(struct work_struct
*work
)
1844 struct mem_cgroup
*memcg
;
1846 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
1847 reclaim_high(memcg
, CHARGE_BATCH
, GFP_KERNEL
);
1851 * Scheduled by try_charge() to be executed from the userland return path
1852 * and reclaims memory over the high limit.
1854 void mem_cgroup_handle_over_high(void)
1856 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
1857 struct mem_cgroup
*memcg
;
1859 if (likely(!nr_pages
))
1862 memcg
= get_mem_cgroup_from_mm(current
->mm
);
1863 reclaim_high(memcg
, nr_pages
, GFP_KERNEL
);
1864 css_put(&memcg
->css
);
1865 current
->memcg_nr_pages_over_high
= 0;
1868 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1869 unsigned int nr_pages
)
1871 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
1872 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
1873 struct mem_cgroup
*mem_over_limit
;
1874 struct page_counter
*counter
;
1875 unsigned long nr_reclaimed
;
1876 bool may_swap
= true;
1877 bool drained
= false;
1879 if (mem_cgroup_is_root(memcg
))
1882 if (consume_stock(memcg
, nr_pages
))
1885 if (!do_memsw_account() ||
1886 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
1887 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
1889 if (do_memsw_account())
1890 page_counter_uncharge(&memcg
->memsw
, batch
);
1891 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
1893 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
1897 if (batch
> nr_pages
) {
1903 * Unlike in global OOM situations, memcg is not in a physical
1904 * memory shortage. Allow dying and OOM-killed tasks to
1905 * bypass the last charges so that they can exit quickly and
1906 * free their memory.
1908 if (unlikely(test_thread_flag(TIF_MEMDIE
) ||
1909 fatal_signal_pending(current
) ||
1910 current
->flags
& PF_EXITING
))
1914 * Prevent unbounded recursion when reclaim operations need to
1915 * allocate memory. This might exceed the limits temporarily,
1916 * but we prefer facilitating memory reclaim and getting back
1917 * under the limit over triggering OOM kills in these cases.
1919 if (unlikely(current
->flags
& PF_MEMALLOC
))
1922 if (unlikely(task_in_memcg_oom(current
)))
1925 if (!gfpflags_allow_blocking(gfp_mask
))
1928 mem_cgroup_events(mem_over_limit
, MEMCG_MAX
, 1);
1930 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
1931 gfp_mask
, may_swap
);
1933 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
1937 drain_all_stock(mem_over_limit
);
1942 if (gfp_mask
& __GFP_NORETRY
)
1945 * Even though the limit is exceeded at this point, reclaim
1946 * may have been able to free some pages. Retry the charge
1947 * before killing the task.
1949 * Only for regular pages, though: huge pages are rather
1950 * unlikely to succeed so close to the limit, and we fall back
1951 * to regular pages anyway in case of failure.
1953 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
1956 * At task move, charge accounts can be doubly counted. So, it's
1957 * better to wait until the end of task_move if something is going on.
1959 if (mem_cgroup_wait_acct_move(mem_over_limit
))
1965 if (gfp_mask
& __GFP_NOFAIL
)
1968 if (fatal_signal_pending(current
))
1971 mem_cgroup_events(mem_over_limit
, MEMCG_OOM
, 1);
1973 mem_cgroup_oom(mem_over_limit
, gfp_mask
,
1974 get_order(nr_pages
* PAGE_SIZE
));
1976 if (!(gfp_mask
& __GFP_NOFAIL
))
1980 * The allocation either can't fail or will lead to more memory
1981 * being freed very soon. Allow memory usage go over the limit
1982 * temporarily by force charging it.
1984 page_counter_charge(&memcg
->memory
, nr_pages
);
1985 if (do_memsw_account())
1986 page_counter_charge(&memcg
->memsw
, nr_pages
);
1987 css_get_many(&memcg
->css
, nr_pages
);
1992 css_get_many(&memcg
->css
, batch
);
1993 if (batch
> nr_pages
)
1994 refill_stock(memcg
, batch
- nr_pages
);
1997 * If the hierarchy is above the normal consumption range, schedule
1998 * reclaim on returning to userland. We can perform reclaim here
1999 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2000 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2001 * not recorded as it most likely matches current's and won't
2002 * change in the meantime. As high limit is checked again before
2003 * reclaim, the cost of mismatch is negligible.
2006 if (page_counter_read(&memcg
->memory
) > memcg
->high
) {
2007 /* Don't bother a random interrupted task */
2008 if (in_interrupt()) {
2009 schedule_work(&memcg
->high_work
);
2012 current
->memcg_nr_pages_over_high
+= batch
;
2013 set_notify_resume(current
);
2016 } while ((memcg
= parent_mem_cgroup(memcg
)));
2021 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2023 if (mem_cgroup_is_root(memcg
))
2026 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2027 if (do_memsw_account())
2028 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2030 css_put_many(&memcg
->css
, nr_pages
);
2033 static void lock_page_lru(struct page
*page
, int *isolated
)
2035 struct zone
*zone
= page_zone(page
);
2037 spin_lock_irq(zone_lru_lock(zone
));
2038 if (PageLRU(page
)) {
2039 struct lruvec
*lruvec
;
2041 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2043 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2049 static void unlock_page_lru(struct page
*page
, int isolated
)
2051 struct zone
*zone
= page_zone(page
);
2054 struct lruvec
*lruvec
;
2056 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2057 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2059 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2061 spin_unlock_irq(zone_lru_lock(zone
));
2064 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2069 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2072 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2073 * may already be on some other mem_cgroup's LRU. Take care of it.
2076 lock_page_lru(page
, &isolated
);
2079 * Nobody should be changing or seriously looking at
2080 * page->mem_cgroup at this point:
2082 * - the page is uncharged
2084 * - the page is off-LRU
2086 * - an anonymous fault has exclusive page access, except for
2087 * a locked page table
2089 * - a page cache insertion, a swapin fault, or a migration
2090 * have the page locked
2092 page
->mem_cgroup
= memcg
;
2095 unlock_page_lru(page
, isolated
);
2099 static int memcg_alloc_cache_id(void)
2104 id
= ida_simple_get(&memcg_cache_ida
,
2105 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2109 if (id
< memcg_nr_cache_ids
)
2113 * There's no space for the new id in memcg_caches arrays,
2114 * so we have to grow them.
2116 down_write(&memcg_cache_ids_sem
);
2118 size
= 2 * (id
+ 1);
2119 if (size
< MEMCG_CACHES_MIN_SIZE
)
2120 size
= MEMCG_CACHES_MIN_SIZE
;
2121 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2122 size
= MEMCG_CACHES_MAX_SIZE
;
2124 err
= memcg_update_all_caches(size
);
2126 err
= memcg_update_all_list_lrus(size
);
2128 memcg_nr_cache_ids
= size
;
2130 up_write(&memcg_cache_ids_sem
);
2133 ida_simple_remove(&memcg_cache_ida
, id
);
2139 static void memcg_free_cache_id(int id
)
2141 ida_simple_remove(&memcg_cache_ida
, id
);
2144 struct memcg_kmem_cache_create_work
{
2145 struct mem_cgroup
*memcg
;
2146 struct kmem_cache
*cachep
;
2147 struct work_struct work
;
2150 static void memcg_kmem_cache_create_func(struct work_struct
*w
)
2152 struct memcg_kmem_cache_create_work
*cw
=
2153 container_of(w
, struct memcg_kmem_cache_create_work
, work
);
2154 struct mem_cgroup
*memcg
= cw
->memcg
;
2155 struct kmem_cache
*cachep
= cw
->cachep
;
2157 memcg_create_kmem_cache(memcg
, cachep
);
2159 css_put(&memcg
->css
);
2164 * Enqueue the creation of a per-memcg kmem_cache.
2166 static void __memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2167 struct kmem_cache
*cachep
)
2169 struct memcg_kmem_cache_create_work
*cw
;
2171 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
);
2175 css_get(&memcg
->css
);
2178 cw
->cachep
= cachep
;
2179 INIT_WORK(&cw
->work
, memcg_kmem_cache_create_func
);
2181 queue_work(memcg_kmem_cache_wq
, &cw
->work
);
2184 static void memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2185 struct kmem_cache
*cachep
)
2188 * We need to stop accounting when we kmalloc, because if the
2189 * corresponding kmalloc cache is not yet created, the first allocation
2190 * in __memcg_schedule_kmem_cache_create will recurse.
2192 * However, it is better to enclose the whole function. Depending on
2193 * the debugging options enabled, INIT_WORK(), for instance, can
2194 * trigger an allocation. This too, will make us recurse. Because at
2195 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2196 * the safest choice is to do it like this, wrapping the whole function.
2198 current
->memcg_kmem_skip_account
= 1;
2199 __memcg_schedule_kmem_cache_create(memcg
, cachep
);
2200 current
->memcg_kmem_skip_account
= 0;
2203 static inline bool memcg_kmem_bypass(void)
2205 if (in_interrupt() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
2211 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2212 * @cachep: the original global kmem cache
2214 * Return the kmem_cache we're supposed to use for a slab allocation.
2215 * We try to use the current memcg's version of the cache.
2217 * If the cache does not exist yet, if we are the first user of it, we
2218 * create it asynchronously in a workqueue and let the current allocation
2219 * go through with the original cache.
2221 * This function takes a reference to the cache it returns to assure it
2222 * won't get destroyed while we are working with it. Once the caller is
2223 * done with it, memcg_kmem_put_cache() must be called to release the
2226 struct kmem_cache
*memcg_kmem_get_cache(struct kmem_cache
*cachep
)
2228 struct mem_cgroup
*memcg
;
2229 struct kmem_cache
*memcg_cachep
;
2232 VM_BUG_ON(!is_root_cache(cachep
));
2234 if (memcg_kmem_bypass())
2237 if (current
->memcg_kmem_skip_account
)
2240 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2241 kmemcg_id
= READ_ONCE(memcg
->kmemcg_id
);
2245 memcg_cachep
= cache_from_memcg_idx(cachep
, kmemcg_id
);
2246 if (likely(memcg_cachep
))
2247 return memcg_cachep
;
2250 * If we are in a safe context (can wait, and not in interrupt
2251 * context), we could be be predictable and return right away.
2252 * This would guarantee that the allocation being performed
2253 * already belongs in the new cache.
2255 * However, there are some clashes that can arrive from locking.
2256 * For instance, because we acquire the slab_mutex while doing
2257 * memcg_create_kmem_cache, this means no further allocation
2258 * could happen with the slab_mutex held. So it's better to
2261 memcg_schedule_kmem_cache_create(memcg
, cachep
);
2263 css_put(&memcg
->css
);
2268 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2269 * @cachep: the cache returned by memcg_kmem_get_cache
2271 void memcg_kmem_put_cache(struct kmem_cache
*cachep
)
2273 if (!is_root_cache(cachep
))
2274 css_put(&cachep
->memcg_params
.memcg
->css
);
2278 * memcg_kmem_charge: charge a kmem page
2279 * @page: page to charge
2280 * @gfp: reclaim mode
2281 * @order: allocation order
2282 * @memcg: memory cgroup to charge
2284 * Returns 0 on success, an error code on failure.
2286 int memcg_kmem_charge_memcg(struct page
*page
, gfp_t gfp
, int order
,
2287 struct mem_cgroup
*memcg
)
2289 unsigned int nr_pages
= 1 << order
;
2290 struct page_counter
*counter
;
2293 ret
= try_charge(memcg
, gfp
, nr_pages
);
2297 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2298 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2299 cancel_charge(memcg
, nr_pages
);
2303 page
->mem_cgroup
= memcg
;
2309 * memcg_kmem_charge: charge a kmem page to the current memory cgroup
2310 * @page: page to charge
2311 * @gfp: reclaim mode
2312 * @order: allocation order
2314 * Returns 0 on success, an error code on failure.
2316 int memcg_kmem_charge(struct page
*page
, gfp_t gfp
, int order
)
2318 struct mem_cgroup
*memcg
;
2321 if (memcg_kmem_bypass())
2324 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2325 if (!mem_cgroup_is_root(memcg
)) {
2326 ret
= memcg_kmem_charge_memcg(page
, gfp
, order
, memcg
);
2328 __SetPageKmemcg(page
);
2330 css_put(&memcg
->css
);
2334 * memcg_kmem_uncharge: uncharge a kmem page
2335 * @page: page to uncharge
2336 * @order: allocation order
2338 void memcg_kmem_uncharge(struct page
*page
, int order
)
2340 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
2341 unsigned int nr_pages
= 1 << order
;
2346 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
2348 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2349 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2351 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2352 if (do_memsw_account())
2353 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2355 page
->mem_cgroup
= NULL
;
2357 /* slab pages do not have PageKmemcg flag set */
2358 if (PageKmemcg(page
))
2359 __ClearPageKmemcg(page
);
2361 css_put_many(&memcg
->css
, nr_pages
);
2363 #endif /* !CONFIG_SLOB */
2365 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2368 * Because tail pages are not marked as "used", set it. We're under
2369 * zone_lru_lock and migration entries setup in all page mappings.
2371 void mem_cgroup_split_huge_fixup(struct page
*head
)
2375 if (mem_cgroup_disabled())
2378 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
2379 head
[i
].mem_cgroup
= head
->mem_cgroup
;
2381 __this_cpu_sub(head
->mem_cgroup
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
],
2384 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2386 #ifdef CONFIG_MEMCG_SWAP
2387 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
2390 int val
= (charge
) ? 1 : -1;
2391 this_cpu_add(memcg
->stat
->count
[MEM_CGROUP_STAT_SWAP
], val
);
2395 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2396 * @entry: swap entry to be moved
2397 * @from: mem_cgroup which the entry is moved from
2398 * @to: mem_cgroup which the entry is moved to
2400 * It succeeds only when the swap_cgroup's record for this entry is the same
2401 * as the mem_cgroup's id of @from.
2403 * Returns 0 on success, -EINVAL on failure.
2405 * The caller must have charged to @to, IOW, called page_counter_charge() about
2406 * both res and memsw, and called css_get().
2408 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
2409 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2411 unsigned short old_id
, new_id
;
2413 old_id
= mem_cgroup_id(from
);
2414 new_id
= mem_cgroup_id(to
);
2416 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
2417 mem_cgroup_swap_statistics(from
, false);
2418 mem_cgroup_swap_statistics(to
, true);
2424 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
2425 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2431 static DEFINE_MUTEX(memcg_limit_mutex
);
2433 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
2434 unsigned long limit
)
2436 unsigned long curusage
;
2437 unsigned long oldusage
;
2438 bool enlarge
= false;
2443 * For keeping hierarchical_reclaim simple, how long we should retry
2444 * is depends on callers. We set our retry-count to be function
2445 * of # of children which we should visit in this loop.
2447 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2448 mem_cgroup_count_children(memcg
);
2450 oldusage
= page_counter_read(&memcg
->memory
);
2453 if (signal_pending(current
)) {
2458 mutex_lock(&memcg_limit_mutex
);
2459 if (limit
> memcg
->memsw
.limit
) {
2460 mutex_unlock(&memcg_limit_mutex
);
2464 if (limit
> memcg
->memory
.limit
)
2466 ret
= page_counter_limit(&memcg
->memory
, limit
);
2467 mutex_unlock(&memcg_limit_mutex
);
2472 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, true);
2474 curusage
= page_counter_read(&memcg
->memory
);
2475 /* Usage is reduced ? */
2476 if (curusage
>= oldusage
)
2479 oldusage
= curusage
;
2480 } while (retry_count
);
2482 if (!ret
&& enlarge
)
2483 memcg_oom_recover(memcg
);
2488 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
2489 unsigned long limit
)
2491 unsigned long curusage
;
2492 unsigned long oldusage
;
2493 bool enlarge
= false;
2497 /* see mem_cgroup_resize_res_limit */
2498 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2499 mem_cgroup_count_children(memcg
);
2501 oldusage
= page_counter_read(&memcg
->memsw
);
2504 if (signal_pending(current
)) {
2509 mutex_lock(&memcg_limit_mutex
);
2510 if (limit
< memcg
->memory
.limit
) {
2511 mutex_unlock(&memcg_limit_mutex
);
2515 if (limit
> memcg
->memsw
.limit
)
2517 ret
= page_counter_limit(&memcg
->memsw
, limit
);
2518 mutex_unlock(&memcg_limit_mutex
);
2523 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, false);
2525 curusage
= page_counter_read(&memcg
->memsw
);
2526 /* Usage is reduced ? */
2527 if (curusage
>= oldusage
)
2530 oldusage
= curusage
;
2531 } while (retry_count
);
2533 if (!ret
&& enlarge
)
2534 memcg_oom_recover(memcg
);
2539 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
2541 unsigned long *total_scanned
)
2543 unsigned long nr_reclaimed
= 0;
2544 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
2545 unsigned long reclaimed
;
2547 struct mem_cgroup_tree_per_node
*mctz
;
2548 unsigned long excess
;
2549 unsigned long nr_scanned
;
2554 mctz
= soft_limit_tree_node(pgdat
->node_id
);
2557 * Do not even bother to check the largest node if the root
2558 * is empty. Do it lockless to prevent lock bouncing. Races
2559 * are acceptable as soft limit is best effort anyway.
2561 if (RB_EMPTY_ROOT(&mctz
->rb_root
))
2565 * This loop can run a while, specially if mem_cgroup's continuously
2566 * keep exceeding their soft limit and putting the system under
2573 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
2578 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
2579 gfp_mask
, &nr_scanned
);
2580 nr_reclaimed
+= reclaimed
;
2581 *total_scanned
+= nr_scanned
;
2582 spin_lock_irq(&mctz
->lock
);
2583 __mem_cgroup_remove_exceeded(mz
, mctz
);
2586 * If we failed to reclaim anything from this memory cgroup
2587 * it is time to move on to the next cgroup
2591 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
2593 excess
= soft_limit_excess(mz
->memcg
);
2595 * One school of thought says that we should not add
2596 * back the node to the tree if reclaim returns 0.
2597 * But our reclaim could return 0, simply because due
2598 * to priority we are exposing a smaller subset of
2599 * memory to reclaim from. Consider this as a longer
2602 /* If excess == 0, no tree ops */
2603 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
2604 spin_unlock_irq(&mctz
->lock
);
2605 css_put(&mz
->memcg
->css
);
2608 * Could not reclaim anything and there are no more
2609 * mem cgroups to try or we seem to be looping without
2610 * reclaiming anything.
2612 if (!nr_reclaimed
&&
2614 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
2616 } while (!nr_reclaimed
);
2618 css_put(&next_mz
->memcg
->css
);
2619 return nr_reclaimed
;
2623 * Test whether @memcg has children, dead or alive. Note that this
2624 * function doesn't care whether @memcg has use_hierarchy enabled and
2625 * returns %true if there are child csses according to the cgroup
2626 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
2628 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
2633 ret
= css_next_child(NULL
, &memcg
->css
);
2639 * Reclaims as many pages from the given memcg as possible.
2641 * Caller is responsible for holding css reference for memcg.
2643 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
2645 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2647 /* we call try-to-free pages for make this cgroup empty */
2648 lru_add_drain_all();
2649 /* try to free all pages in this cgroup */
2650 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
2653 if (signal_pending(current
))
2656 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
2660 /* maybe some writeback is necessary */
2661 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
2669 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
2670 char *buf
, size_t nbytes
,
2673 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2675 if (mem_cgroup_is_root(memcg
))
2677 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
2680 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
2683 return mem_cgroup_from_css(css
)->use_hierarchy
;
2686 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
2687 struct cftype
*cft
, u64 val
)
2690 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2691 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
2693 if (memcg
->use_hierarchy
== val
)
2697 * If parent's use_hierarchy is set, we can't make any modifications
2698 * in the child subtrees. If it is unset, then the change can
2699 * occur, provided the current cgroup has no children.
2701 * For the root cgroup, parent_mem is NULL, we allow value to be
2702 * set if there are no children.
2704 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
2705 (val
== 1 || val
== 0)) {
2706 if (!memcg_has_children(memcg
))
2707 memcg
->use_hierarchy
= val
;
2716 static void tree_stat(struct mem_cgroup
*memcg
, unsigned long *stat
)
2718 struct mem_cgroup
*iter
;
2721 memset(stat
, 0, sizeof(*stat
) * MEMCG_NR_STAT
);
2723 for_each_mem_cgroup_tree(iter
, memcg
) {
2724 for (i
= 0; i
< MEMCG_NR_STAT
; i
++)
2725 stat
[i
] += mem_cgroup_read_stat(iter
, i
);
2729 static void tree_events(struct mem_cgroup
*memcg
, unsigned long *events
)
2731 struct mem_cgroup
*iter
;
2734 memset(events
, 0, sizeof(*events
) * MEMCG_NR_EVENTS
);
2736 for_each_mem_cgroup_tree(iter
, memcg
) {
2737 for (i
= 0; i
< MEMCG_NR_EVENTS
; i
++)
2738 events
[i
] += mem_cgroup_read_events(iter
, i
);
2742 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
2744 unsigned long val
= 0;
2746 if (mem_cgroup_is_root(memcg
)) {
2747 struct mem_cgroup
*iter
;
2749 for_each_mem_cgroup_tree(iter
, memcg
) {
2750 val
+= mem_cgroup_read_stat(iter
,
2751 MEM_CGROUP_STAT_CACHE
);
2752 val
+= mem_cgroup_read_stat(iter
,
2753 MEM_CGROUP_STAT_RSS
);
2755 val
+= mem_cgroup_read_stat(iter
,
2756 MEM_CGROUP_STAT_SWAP
);
2760 val
= page_counter_read(&memcg
->memory
);
2762 val
= page_counter_read(&memcg
->memsw
);
2775 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
2778 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2779 struct page_counter
*counter
;
2781 switch (MEMFILE_TYPE(cft
->private)) {
2783 counter
= &memcg
->memory
;
2786 counter
= &memcg
->memsw
;
2789 counter
= &memcg
->kmem
;
2792 counter
= &memcg
->tcpmem
;
2798 switch (MEMFILE_ATTR(cft
->private)) {
2800 if (counter
== &memcg
->memory
)
2801 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
2802 if (counter
== &memcg
->memsw
)
2803 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
2804 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
2806 return (u64
)counter
->limit
* PAGE_SIZE
;
2808 return (u64
)counter
->watermark
* PAGE_SIZE
;
2810 return counter
->failcnt
;
2811 case RES_SOFT_LIMIT
:
2812 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
2819 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2823 if (cgroup_memory_nokmem
)
2826 BUG_ON(memcg
->kmemcg_id
>= 0);
2827 BUG_ON(memcg
->kmem_state
);
2829 memcg_id
= memcg_alloc_cache_id();
2833 static_branch_inc(&memcg_kmem_enabled_key
);
2835 * A memory cgroup is considered kmem-online as soon as it gets
2836 * kmemcg_id. Setting the id after enabling static branching will
2837 * guarantee no one starts accounting before all call sites are
2840 memcg
->kmemcg_id
= memcg_id
;
2841 memcg
->kmem_state
= KMEM_ONLINE
;
2842 INIT_LIST_HEAD(&memcg
->kmem_caches
);
2847 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2849 struct cgroup_subsys_state
*css
;
2850 struct mem_cgroup
*parent
, *child
;
2853 if (memcg
->kmem_state
!= KMEM_ONLINE
)
2856 * Clear the online state before clearing memcg_caches array
2857 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
2858 * guarantees that no cache will be created for this cgroup
2859 * after we are done (see memcg_create_kmem_cache()).
2861 memcg
->kmem_state
= KMEM_ALLOCATED
;
2863 memcg_deactivate_kmem_caches(memcg
);
2865 kmemcg_id
= memcg
->kmemcg_id
;
2866 BUG_ON(kmemcg_id
< 0);
2868 parent
= parent_mem_cgroup(memcg
);
2870 parent
= root_mem_cgroup
;
2873 * Change kmemcg_id of this cgroup and all its descendants to the
2874 * parent's id, and then move all entries from this cgroup's list_lrus
2875 * to ones of the parent. After we have finished, all list_lrus
2876 * corresponding to this cgroup are guaranteed to remain empty. The
2877 * ordering is imposed by list_lru_node->lock taken by
2878 * memcg_drain_all_list_lrus().
2880 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
2881 css_for_each_descendant_pre(css
, &memcg
->css
) {
2882 child
= mem_cgroup_from_css(css
);
2883 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
2884 child
->kmemcg_id
= parent
->kmemcg_id
;
2885 if (!memcg
->use_hierarchy
)
2890 memcg_drain_all_list_lrus(kmemcg_id
, parent
->kmemcg_id
);
2892 memcg_free_cache_id(kmemcg_id
);
2895 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2897 /* css_alloc() failed, offlining didn't happen */
2898 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
2899 memcg_offline_kmem(memcg
);
2901 if (memcg
->kmem_state
== KMEM_ALLOCATED
) {
2902 memcg_destroy_kmem_caches(memcg
);
2903 static_branch_dec(&memcg_kmem_enabled_key
);
2904 WARN_ON(page_counter_read(&memcg
->kmem
));
2908 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2912 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2915 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2918 #endif /* !CONFIG_SLOB */
2920 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
2921 unsigned long limit
)
2925 mutex_lock(&memcg_limit_mutex
);
2926 ret
= page_counter_limit(&memcg
->kmem
, limit
);
2927 mutex_unlock(&memcg_limit_mutex
);
2931 static int memcg_update_tcp_limit(struct mem_cgroup
*memcg
, unsigned long limit
)
2935 mutex_lock(&memcg_limit_mutex
);
2937 ret
= page_counter_limit(&memcg
->tcpmem
, limit
);
2941 if (!memcg
->tcpmem_active
) {
2943 * The active flag needs to be written after the static_key
2944 * update. This is what guarantees that the socket activation
2945 * function is the last one to run. See mem_cgroup_sk_alloc()
2946 * for details, and note that we don't mark any socket as
2947 * belonging to this memcg until that flag is up.
2949 * We need to do this, because static_keys will span multiple
2950 * sites, but we can't control their order. If we mark a socket
2951 * as accounted, but the accounting functions are not patched in
2952 * yet, we'll lose accounting.
2954 * We never race with the readers in mem_cgroup_sk_alloc(),
2955 * because when this value change, the code to process it is not
2958 static_branch_inc(&memcg_sockets_enabled_key
);
2959 memcg
->tcpmem_active
= true;
2962 mutex_unlock(&memcg_limit_mutex
);
2967 * The user of this function is...
2970 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
2971 char *buf
, size_t nbytes
, loff_t off
)
2973 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2974 unsigned long nr_pages
;
2977 buf
= strstrip(buf
);
2978 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
2982 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
2984 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
2988 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
2990 ret
= mem_cgroup_resize_limit(memcg
, nr_pages
);
2993 ret
= mem_cgroup_resize_memsw_limit(memcg
, nr_pages
);
2996 ret
= memcg_update_kmem_limit(memcg
, nr_pages
);
2999 ret
= memcg_update_tcp_limit(memcg
, nr_pages
);
3003 case RES_SOFT_LIMIT
:
3004 memcg
->soft_limit
= nr_pages
;
3008 return ret
?: nbytes
;
3011 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3012 size_t nbytes
, loff_t off
)
3014 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3015 struct page_counter
*counter
;
3017 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3019 counter
= &memcg
->memory
;
3022 counter
= &memcg
->memsw
;
3025 counter
= &memcg
->kmem
;
3028 counter
= &memcg
->tcpmem
;
3034 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3036 page_counter_reset_watermark(counter
);
3039 counter
->failcnt
= 0;
3048 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3051 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3055 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3056 struct cftype
*cft
, u64 val
)
3058 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3060 if (val
& ~MOVE_MASK
)
3064 * No kind of locking is needed in here, because ->can_attach() will
3065 * check this value once in the beginning of the process, and then carry
3066 * on with stale data. This means that changes to this value will only
3067 * affect task migrations starting after the change.
3069 memcg
->move_charge_at_immigrate
= val
;
3073 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3074 struct cftype
*cft
, u64 val
)
3081 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3085 unsigned int lru_mask
;
3088 static const struct numa_stat stats
[] = {
3089 { "total", LRU_ALL
},
3090 { "file", LRU_ALL_FILE
},
3091 { "anon", LRU_ALL_ANON
},
3092 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3094 const struct numa_stat
*stat
;
3097 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3099 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3100 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
3101 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
3102 for_each_node_state(nid
, N_MEMORY
) {
3103 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3105 seq_printf(m
, " N%d=%lu", nid
, nr
);
3110 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3111 struct mem_cgroup
*iter
;
3114 for_each_mem_cgroup_tree(iter
, memcg
)
3115 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
3116 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
3117 for_each_node_state(nid
, N_MEMORY
) {
3119 for_each_mem_cgroup_tree(iter
, memcg
)
3120 nr
+= mem_cgroup_node_nr_lru_pages(
3121 iter
, nid
, stat
->lru_mask
);
3122 seq_printf(m
, " N%d=%lu", nid
, nr
);
3129 #endif /* CONFIG_NUMA */
3131 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3133 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3134 unsigned long memory
, memsw
;
3135 struct mem_cgroup
*mi
;
3138 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_stat_names
) !=
3139 MEM_CGROUP_STAT_NSTATS
);
3140 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_events_names
) !=
3141 MEM_CGROUP_EVENTS_NSTATS
);
3142 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
3144 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3145 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_memsw_account())
3147 seq_printf(m
, "%s %lu\n", mem_cgroup_stat_names
[i
],
3148 mem_cgroup_read_stat(memcg
, i
) * PAGE_SIZE
);
3151 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++)
3152 seq_printf(m
, "%s %lu\n", mem_cgroup_events_names
[i
],
3153 mem_cgroup_read_events(memcg
, i
));
3155 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3156 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
3157 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
3159 /* Hierarchical information */
3160 memory
= memsw
= PAGE_COUNTER_MAX
;
3161 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3162 memory
= min(memory
, mi
->memory
.limit
);
3163 memsw
= min(memsw
, mi
->memsw
.limit
);
3165 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3166 (u64
)memory
* PAGE_SIZE
);
3167 if (do_memsw_account())
3168 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3169 (u64
)memsw
* PAGE_SIZE
);
3171 for (i
= 0; i
< MEM_CGROUP_STAT_NSTATS
; i
++) {
3172 unsigned long long val
= 0;
3174 if (i
== MEM_CGROUP_STAT_SWAP
&& !do_memsw_account())
3176 for_each_mem_cgroup_tree(mi
, memcg
)
3177 val
+= mem_cgroup_read_stat(mi
, i
) * PAGE_SIZE
;
3178 seq_printf(m
, "total_%s %llu\n", mem_cgroup_stat_names
[i
], val
);
3181 for (i
= 0; i
< MEM_CGROUP_EVENTS_NSTATS
; i
++) {
3182 unsigned long long val
= 0;
3184 for_each_mem_cgroup_tree(mi
, memcg
)
3185 val
+= mem_cgroup_read_events(mi
, i
);
3186 seq_printf(m
, "total_%s %llu\n",
3187 mem_cgroup_events_names
[i
], val
);
3190 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
3191 unsigned long long val
= 0;
3193 for_each_mem_cgroup_tree(mi
, memcg
)
3194 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
3195 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
3198 #ifdef CONFIG_DEBUG_VM
3201 struct mem_cgroup_per_node
*mz
;
3202 struct zone_reclaim_stat
*rstat
;
3203 unsigned long recent_rotated
[2] = {0, 0};
3204 unsigned long recent_scanned
[2] = {0, 0};
3206 for_each_online_pgdat(pgdat
) {
3207 mz
= mem_cgroup_nodeinfo(memcg
, pgdat
->node_id
);
3208 rstat
= &mz
->lruvec
.reclaim_stat
;
3210 recent_rotated
[0] += rstat
->recent_rotated
[0];
3211 recent_rotated
[1] += rstat
->recent_rotated
[1];
3212 recent_scanned
[0] += rstat
->recent_scanned
[0];
3213 recent_scanned
[1] += rstat
->recent_scanned
[1];
3215 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
3216 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
3217 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
3218 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
3225 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3228 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3230 return mem_cgroup_swappiness(memcg
);
3233 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3234 struct cftype
*cft
, u64 val
)
3236 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3242 memcg
->swappiness
= val
;
3244 vm_swappiness
= val
;
3249 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3251 struct mem_cgroup_threshold_ary
*t
;
3252 unsigned long usage
;
3257 t
= rcu_dereference(memcg
->thresholds
.primary
);
3259 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3264 usage
= mem_cgroup_usage(memcg
, swap
);
3267 * current_threshold points to threshold just below or equal to usage.
3268 * If it's not true, a threshold was crossed after last
3269 * call of __mem_cgroup_threshold().
3271 i
= t
->current_threshold
;
3274 * Iterate backward over array of thresholds starting from
3275 * current_threshold and check if a threshold is crossed.
3276 * If none of thresholds below usage is crossed, we read
3277 * only one element of the array here.
3279 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3280 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3282 /* i = current_threshold + 1 */
3286 * Iterate forward over array of thresholds starting from
3287 * current_threshold+1 and check if a threshold is crossed.
3288 * If none of thresholds above usage is crossed, we read
3289 * only one element of the array here.
3291 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
3292 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3294 /* Update current_threshold */
3295 t
->current_threshold
= i
- 1;
3300 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
3303 __mem_cgroup_threshold(memcg
, false);
3304 if (do_memsw_account())
3305 __mem_cgroup_threshold(memcg
, true);
3307 memcg
= parent_mem_cgroup(memcg
);
3311 static int compare_thresholds(const void *a
, const void *b
)
3313 const struct mem_cgroup_threshold
*_a
= a
;
3314 const struct mem_cgroup_threshold
*_b
= b
;
3316 if (_a
->threshold
> _b
->threshold
)
3319 if (_a
->threshold
< _b
->threshold
)
3325 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
3327 struct mem_cgroup_eventfd_list
*ev
;
3329 spin_lock(&memcg_oom_lock
);
3331 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
3332 eventfd_signal(ev
->eventfd
, 1);
3334 spin_unlock(&memcg_oom_lock
);
3338 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
3340 struct mem_cgroup
*iter
;
3342 for_each_mem_cgroup_tree(iter
, memcg
)
3343 mem_cgroup_oom_notify_cb(iter
);
3346 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3347 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
3349 struct mem_cgroup_thresholds
*thresholds
;
3350 struct mem_cgroup_threshold_ary
*new;
3351 unsigned long threshold
;
3352 unsigned long usage
;
3355 ret
= page_counter_memparse(args
, "-1", &threshold
);
3359 mutex_lock(&memcg
->thresholds_lock
);
3362 thresholds
= &memcg
->thresholds
;
3363 usage
= mem_cgroup_usage(memcg
, false);
3364 } else if (type
== _MEMSWAP
) {
3365 thresholds
= &memcg
->memsw_thresholds
;
3366 usage
= mem_cgroup_usage(memcg
, true);
3370 /* Check if a threshold crossed before adding a new one */
3371 if (thresholds
->primary
)
3372 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3374 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
3376 /* Allocate memory for new array of thresholds */
3377 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
3385 /* Copy thresholds (if any) to new array */
3386 if (thresholds
->primary
) {
3387 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
3388 sizeof(struct mem_cgroup_threshold
));
3391 /* Add new threshold */
3392 new->entries
[size
- 1].eventfd
= eventfd
;
3393 new->entries
[size
- 1].threshold
= threshold
;
3395 /* Sort thresholds. Registering of new threshold isn't time-critical */
3396 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
3397 compare_thresholds
, NULL
);
3399 /* Find current threshold */
3400 new->current_threshold
= -1;
3401 for (i
= 0; i
< size
; i
++) {
3402 if (new->entries
[i
].threshold
<= usage
) {
3404 * new->current_threshold will not be used until
3405 * rcu_assign_pointer(), so it's safe to increment
3408 ++new->current_threshold
;
3413 /* Free old spare buffer and save old primary buffer as spare */
3414 kfree(thresholds
->spare
);
3415 thresholds
->spare
= thresholds
->primary
;
3417 rcu_assign_pointer(thresholds
->primary
, new);
3419 /* To be sure that nobody uses thresholds */
3423 mutex_unlock(&memcg
->thresholds_lock
);
3428 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3429 struct eventfd_ctx
*eventfd
, const char *args
)
3431 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
3434 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3435 struct eventfd_ctx
*eventfd
, const char *args
)
3437 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
3440 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3441 struct eventfd_ctx
*eventfd
, enum res_type type
)
3443 struct mem_cgroup_thresholds
*thresholds
;
3444 struct mem_cgroup_threshold_ary
*new;
3445 unsigned long usage
;
3448 mutex_lock(&memcg
->thresholds_lock
);
3451 thresholds
= &memcg
->thresholds
;
3452 usage
= mem_cgroup_usage(memcg
, false);
3453 } else if (type
== _MEMSWAP
) {
3454 thresholds
= &memcg
->memsw_thresholds
;
3455 usage
= mem_cgroup_usage(memcg
, true);
3459 if (!thresholds
->primary
)
3462 /* Check if a threshold crossed before removing */
3463 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3465 /* Calculate new number of threshold */
3467 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
3468 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
3472 new = thresholds
->spare
;
3474 /* Set thresholds array to NULL if we don't have thresholds */
3483 /* Copy thresholds and find current threshold */
3484 new->current_threshold
= -1;
3485 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
3486 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
3489 new->entries
[j
] = thresholds
->primary
->entries
[i
];
3490 if (new->entries
[j
].threshold
<= usage
) {
3492 * new->current_threshold will not be used
3493 * until rcu_assign_pointer(), so it's safe to increment
3496 ++new->current_threshold
;
3502 /* Swap primary and spare array */
3503 thresholds
->spare
= thresholds
->primary
;
3505 rcu_assign_pointer(thresholds
->primary
, new);
3507 /* To be sure that nobody uses thresholds */
3510 /* If all events are unregistered, free the spare array */
3512 kfree(thresholds
->spare
);
3513 thresholds
->spare
= NULL
;
3516 mutex_unlock(&memcg
->thresholds_lock
);
3519 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3520 struct eventfd_ctx
*eventfd
)
3522 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
3525 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3526 struct eventfd_ctx
*eventfd
)
3528 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
3531 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
3532 struct eventfd_ctx
*eventfd
, const char *args
)
3534 struct mem_cgroup_eventfd_list
*event
;
3536 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
3540 spin_lock(&memcg_oom_lock
);
3542 event
->eventfd
= eventfd
;
3543 list_add(&event
->list
, &memcg
->oom_notify
);
3545 /* already in OOM ? */
3546 if (memcg
->under_oom
)
3547 eventfd_signal(eventfd
, 1);
3548 spin_unlock(&memcg_oom_lock
);
3553 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
3554 struct eventfd_ctx
*eventfd
)
3556 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
3558 spin_lock(&memcg_oom_lock
);
3560 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
3561 if (ev
->eventfd
== eventfd
) {
3562 list_del(&ev
->list
);
3567 spin_unlock(&memcg_oom_lock
);
3570 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
3572 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
3574 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
3575 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
3579 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
3580 struct cftype
*cft
, u64 val
)
3582 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3584 /* cannot set to root cgroup and only 0 and 1 are allowed */
3585 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
3588 memcg
->oom_kill_disable
= val
;
3590 memcg_oom_recover(memcg
);
3595 #ifdef CONFIG_CGROUP_WRITEBACK
3597 struct list_head
*mem_cgroup_cgwb_list(struct mem_cgroup
*memcg
)
3599 return &memcg
->cgwb_list
;
3602 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3604 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
3607 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3609 wb_domain_exit(&memcg
->cgwb_domain
);
3612 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3614 wb_domain_size_changed(&memcg
->cgwb_domain
);
3617 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
3619 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3621 if (!memcg
->css
.parent
)
3624 return &memcg
->cgwb_domain
;
3628 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
3629 * @wb: bdi_writeback in question
3630 * @pfilepages: out parameter for number of file pages
3631 * @pheadroom: out parameter for number of allocatable pages according to memcg
3632 * @pdirty: out parameter for number of dirty pages
3633 * @pwriteback: out parameter for number of pages under writeback
3635 * Determine the numbers of file, headroom, dirty, and writeback pages in
3636 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
3637 * is a bit more involved.
3639 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
3640 * headroom is calculated as the lowest headroom of itself and the
3641 * ancestors. Note that this doesn't consider the actual amount of
3642 * available memory in the system. The caller should further cap
3643 * *@pheadroom accordingly.
3645 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
3646 unsigned long *pheadroom
, unsigned long *pdirty
,
3647 unsigned long *pwriteback
)
3649 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3650 struct mem_cgroup
*parent
;
3652 *pdirty
= mem_cgroup_read_stat(memcg
, MEM_CGROUP_STAT_DIRTY
);
3654 /* this should eventually include NR_UNSTABLE_NFS */
3655 *pwriteback
= mem_cgroup_read_stat(memcg
, MEM_CGROUP_STAT_WRITEBACK
);
3656 *pfilepages
= mem_cgroup_nr_lru_pages(memcg
, (1 << LRU_INACTIVE_FILE
) |
3657 (1 << LRU_ACTIVE_FILE
));
3658 *pheadroom
= PAGE_COUNTER_MAX
;
3660 while ((parent
= parent_mem_cgroup(memcg
))) {
3661 unsigned long ceiling
= min(memcg
->memory
.limit
, memcg
->high
);
3662 unsigned long used
= page_counter_read(&memcg
->memory
);
3664 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
3669 #else /* CONFIG_CGROUP_WRITEBACK */
3671 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3676 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3680 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3684 #endif /* CONFIG_CGROUP_WRITEBACK */
3687 * DO NOT USE IN NEW FILES.
3689 * "cgroup.event_control" implementation.
3691 * This is way over-engineered. It tries to support fully configurable
3692 * events for each user. Such level of flexibility is completely
3693 * unnecessary especially in the light of the planned unified hierarchy.
3695 * Please deprecate this and replace with something simpler if at all
3700 * Unregister event and free resources.
3702 * Gets called from workqueue.
3704 static void memcg_event_remove(struct work_struct
*work
)
3706 struct mem_cgroup_event
*event
=
3707 container_of(work
, struct mem_cgroup_event
, remove
);
3708 struct mem_cgroup
*memcg
= event
->memcg
;
3710 remove_wait_queue(event
->wqh
, &event
->wait
);
3712 event
->unregister_event(memcg
, event
->eventfd
);
3714 /* Notify userspace the event is going away. */
3715 eventfd_signal(event
->eventfd
, 1);
3717 eventfd_ctx_put(event
->eventfd
);
3719 css_put(&memcg
->css
);
3723 * Gets called on POLLHUP on eventfd when user closes it.
3725 * Called with wqh->lock held and interrupts disabled.
3727 static int memcg_event_wake(wait_queue_t
*wait
, unsigned mode
,
3728 int sync
, void *key
)
3730 struct mem_cgroup_event
*event
=
3731 container_of(wait
, struct mem_cgroup_event
, wait
);
3732 struct mem_cgroup
*memcg
= event
->memcg
;
3733 unsigned long flags
= (unsigned long)key
;
3735 if (flags
& POLLHUP
) {
3737 * If the event has been detached at cgroup removal, we
3738 * can simply return knowing the other side will cleanup
3741 * We can't race against event freeing since the other
3742 * side will require wqh->lock via remove_wait_queue(),
3745 spin_lock(&memcg
->event_list_lock
);
3746 if (!list_empty(&event
->list
)) {
3747 list_del_init(&event
->list
);
3749 * We are in atomic context, but cgroup_event_remove()
3750 * may sleep, so we have to call it in workqueue.
3752 schedule_work(&event
->remove
);
3754 spin_unlock(&memcg
->event_list_lock
);
3760 static void memcg_event_ptable_queue_proc(struct file
*file
,
3761 wait_queue_head_t
*wqh
, poll_table
*pt
)
3763 struct mem_cgroup_event
*event
=
3764 container_of(pt
, struct mem_cgroup_event
, pt
);
3767 add_wait_queue(wqh
, &event
->wait
);
3771 * DO NOT USE IN NEW FILES.
3773 * Parse input and register new cgroup event handler.
3775 * Input must be in format '<event_fd> <control_fd> <args>'.
3776 * Interpretation of args is defined by control file implementation.
3778 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
3779 char *buf
, size_t nbytes
, loff_t off
)
3781 struct cgroup_subsys_state
*css
= of_css(of
);
3782 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3783 struct mem_cgroup_event
*event
;
3784 struct cgroup_subsys_state
*cfile_css
;
3785 unsigned int efd
, cfd
;
3792 buf
= strstrip(buf
);
3794 efd
= simple_strtoul(buf
, &endp
, 10);
3799 cfd
= simple_strtoul(buf
, &endp
, 10);
3800 if ((*endp
!= ' ') && (*endp
!= '\0'))
3804 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
3808 event
->memcg
= memcg
;
3809 INIT_LIST_HEAD(&event
->list
);
3810 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
3811 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
3812 INIT_WORK(&event
->remove
, memcg_event_remove
);
3820 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
3821 if (IS_ERR(event
->eventfd
)) {
3822 ret
= PTR_ERR(event
->eventfd
);
3829 goto out_put_eventfd
;
3832 /* the process need read permission on control file */
3833 /* AV: shouldn't we check that it's been opened for read instead? */
3834 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
3839 * Determine the event callbacks and set them in @event. This used
3840 * to be done via struct cftype but cgroup core no longer knows
3841 * about these events. The following is crude but the whole thing
3842 * is for compatibility anyway.
3844 * DO NOT ADD NEW FILES.
3846 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
3848 if (!strcmp(name
, "memory.usage_in_bytes")) {
3849 event
->register_event
= mem_cgroup_usage_register_event
;
3850 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
3851 } else if (!strcmp(name
, "memory.oom_control")) {
3852 event
->register_event
= mem_cgroup_oom_register_event
;
3853 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
3854 } else if (!strcmp(name
, "memory.pressure_level")) {
3855 event
->register_event
= vmpressure_register_event
;
3856 event
->unregister_event
= vmpressure_unregister_event
;
3857 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
3858 event
->register_event
= memsw_cgroup_usage_register_event
;
3859 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
3866 * Verify @cfile should belong to @css. Also, remaining events are
3867 * automatically removed on cgroup destruction but the removal is
3868 * asynchronous, so take an extra ref on @css.
3870 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
3871 &memory_cgrp_subsys
);
3873 if (IS_ERR(cfile_css
))
3875 if (cfile_css
!= css
) {
3880 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
3884 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
3886 spin_lock(&memcg
->event_list_lock
);
3887 list_add(&event
->list
, &memcg
->event_list
);
3888 spin_unlock(&memcg
->event_list_lock
);
3900 eventfd_ctx_put(event
->eventfd
);
3909 static struct cftype mem_cgroup_legacy_files
[] = {
3911 .name
= "usage_in_bytes",
3912 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
3913 .read_u64
= mem_cgroup_read_u64
,
3916 .name
= "max_usage_in_bytes",
3917 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
3918 .write
= mem_cgroup_reset
,
3919 .read_u64
= mem_cgroup_read_u64
,
3922 .name
= "limit_in_bytes",
3923 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
3924 .write
= mem_cgroup_write
,
3925 .read_u64
= mem_cgroup_read_u64
,
3928 .name
= "soft_limit_in_bytes",
3929 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
3930 .write
= mem_cgroup_write
,
3931 .read_u64
= mem_cgroup_read_u64
,
3935 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
3936 .write
= mem_cgroup_reset
,
3937 .read_u64
= mem_cgroup_read_u64
,
3941 .seq_show
= memcg_stat_show
,
3944 .name
= "force_empty",
3945 .write
= mem_cgroup_force_empty_write
,
3948 .name
= "use_hierarchy",
3949 .write_u64
= mem_cgroup_hierarchy_write
,
3950 .read_u64
= mem_cgroup_hierarchy_read
,
3953 .name
= "cgroup.event_control", /* XXX: for compat */
3954 .write
= memcg_write_event_control
,
3955 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
3958 .name
= "swappiness",
3959 .read_u64
= mem_cgroup_swappiness_read
,
3960 .write_u64
= mem_cgroup_swappiness_write
,
3963 .name
= "move_charge_at_immigrate",
3964 .read_u64
= mem_cgroup_move_charge_read
,
3965 .write_u64
= mem_cgroup_move_charge_write
,
3968 .name
= "oom_control",
3969 .seq_show
= mem_cgroup_oom_control_read
,
3970 .write_u64
= mem_cgroup_oom_control_write
,
3971 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
3974 .name
= "pressure_level",
3978 .name
= "numa_stat",
3979 .seq_show
= memcg_numa_stat_show
,
3983 .name
= "kmem.limit_in_bytes",
3984 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
3985 .write
= mem_cgroup_write
,
3986 .read_u64
= mem_cgroup_read_u64
,
3989 .name
= "kmem.usage_in_bytes",
3990 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
3991 .read_u64
= mem_cgroup_read_u64
,
3994 .name
= "kmem.failcnt",
3995 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
3996 .write
= mem_cgroup_reset
,
3997 .read_u64
= mem_cgroup_read_u64
,
4000 .name
= "kmem.max_usage_in_bytes",
4001 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4002 .write
= mem_cgroup_reset
,
4003 .read_u64
= mem_cgroup_read_u64
,
4005 #ifdef CONFIG_SLABINFO
4007 .name
= "kmem.slabinfo",
4008 .seq_start
= memcg_slab_start
,
4009 .seq_next
= memcg_slab_next
,
4010 .seq_stop
= memcg_slab_stop
,
4011 .seq_show
= memcg_slab_show
,
4015 .name
= "kmem.tcp.limit_in_bytes",
4016 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4017 .write
= mem_cgroup_write
,
4018 .read_u64
= mem_cgroup_read_u64
,
4021 .name
= "kmem.tcp.usage_in_bytes",
4022 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4023 .read_u64
= mem_cgroup_read_u64
,
4026 .name
= "kmem.tcp.failcnt",
4027 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4028 .write
= mem_cgroup_reset
,
4029 .read_u64
= mem_cgroup_read_u64
,
4032 .name
= "kmem.tcp.max_usage_in_bytes",
4033 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4034 .write
= mem_cgroup_reset
,
4035 .read_u64
= mem_cgroup_read_u64
,
4037 { }, /* terminate */
4041 * Private memory cgroup IDR
4043 * Swap-out records and page cache shadow entries need to store memcg
4044 * references in constrained space, so we maintain an ID space that is
4045 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4046 * memory-controlled cgroups to 64k.
4048 * However, there usually are many references to the oflline CSS after
4049 * the cgroup has been destroyed, such as page cache or reclaimable
4050 * slab objects, that don't need to hang on to the ID. We want to keep
4051 * those dead CSS from occupying IDs, or we might quickly exhaust the
4052 * relatively small ID space and prevent the creation of new cgroups
4053 * even when there are much fewer than 64k cgroups - possibly none.
4055 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4056 * be freed and recycled when it's no longer needed, which is usually
4057 * when the CSS is offlined.
4059 * The only exception to that are records of swapped out tmpfs/shmem
4060 * pages that need to be attributed to live ancestors on swapin. But
4061 * those references are manageable from userspace.
4064 static DEFINE_IDR(mem_cgroup_idr
);
4066 static void mem_cgroup_id_get_many(struct mem_cgroup
*memcg
, unsigned int n
)
4068 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) <= 0);
4069 atomic_add(n
, &memcg
->id
.ref
);
4072 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
4074 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) < n
);
4075 if (atomic_sub_and_test(n
, &memcg
->id
.ref
)) {
4076 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4079 /* Memcg ID pins CSS */
4080 css_put(&memcg
->css
);
4084 static inline void mem_cgroup_id_get(struct mem_cgroup
*memcg
)
4086 mem_cgroup_id_get_many(memcg
, 1);
4089 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
4091 mem_cgroup_id_put_many(memcg
, 1);
4095 * mem_cgroup_from_id - look up a memcg from a memcg id
4096 * @id: the memcg id to look up
4098 * Caller must hold rcu_read_lock().
4100 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
4102 WARN_ON_ONCE(!rcu_read_lock_held());
4103 return idr_find(&mem_cgroup_idr
, id
);
4106 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4108 struct mem_cgroup_per_node
*pn
;
4111 * This routine is called against possible nodes.
4112 * But it's BUG to call kmalloc() against offline node.
4114 * TODO: this routine can waste much memory for nodes which will
4115 * never be onlined. It's better to use memory hotplug callback
4118 if (!node_state(node
, N_NORMAL_MEMORY
))
4120 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4124 lruvec_init(&pn
->lruvec
);
4125 pn
->usage_in_excess
= 0;
4126 pn
->on_tree
= false;
4129 memcg
->nodeinfo
[node
] = pn
;
4133 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4135 kfree(memcg
->nodeinfo
[node
]);
4138 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
4142 memcg_wb_domain_exit(memcg
);
4144 free_mem_cgroup_per_node_info(memcg
, node
);
4145 free_percpu(memcg
->stat
);
4149 static struct mem_cgroup
*mem_cgroup_alloc(void)
4151 struct mem_cgroup
*memcg
;
4155 size
= sizeof(struct mem_cgroup
);
4156 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
4158 memcg
= kzalloc(size
, GFP_KERNEL
);
4162 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
4163 1, MEM_CGROUP_ID_MAX
,
4165 if (memcg
->id
.id
< 0)
4168 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
4173 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
4176 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
4179 INIT_WORK(&memcg
->high_work
, high_work_func
);
4180 memcg
->last_scanned_node
= MAX_NUMNODES
;
4181 INIT_LIST_HEAD(&memcg
->oom_notify
);
4182 mutex_init(&memcg
->thresholds_lock
);
4183 spin_lock_init(&memcg
->move_lock
);
4184 vmpressure_init(&memcg
->vmpressure
);
4185 INIT_LIST_HEAD(&memcg
->event_list
);
4186 spin_lock_init(&memcg
->event_list_lock
);
4187 memcg
->socket_pressure
= jiffies
;
4189 memcg
->kmemcg_id
= -1;
4191 #ifdef CONFIG_CGROUP_WRITEBACK
4192 INIT_LIST_HEAD(&memcg
->cgwb_list
);
4194 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
4197 if (memcg
->id
.id
> 0)
4198 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4199 mem_cgroup_free(memcg
);
4203 static struct cgroup_subsys_state
* __ref
4204 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
4206 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
4207 struct mem_cgroup
*memcg
;
4208 long error
= -ENOMEM
;
4210 memcg
= mem_cgroup_alloc();
4212 return ERR_PTR(error
);
4214 memcg
->high
= PAGE_COUNTER_MAX
;
4215 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4217 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
4218 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
4220 if (parent
&& parent
->use_hierarchy
) {
4221 memcg
->use_hierarchy
= true;
4222 page_counter_init(&memcg
->memory
, &parent
->memory
);
4223 page_counter_init(&memcg
->swap
, &parent
->swap
);
4224 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
4225 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
4226 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
4228 page_counter_init(&memcg
->memory
, NULL
);
4229 page_counter_init(&memcg
->swap
, NULL
);
4230 page_counter_init(&memcg
->memsw
, NULL
);
4231 page_counter_init(&memcg
->kmem
, NULL
);
4232 page_counter_init(&memcg
->tcpmem
, NULL
);
4234 * Deeper hierachy with use_hierarchy == false doesn't make
4235 * much sense so let cgroup subsystem know about this
4236 * unfortunate state in our controller.
4238 if (parent
!= root_mem_cgroup
)
4239 memory_cgrp_subsys
.broken_hierarchy
= true;
4242 /* The following stuff does not apply to the root */
4244 root_mem_cgroup
= memcg
;
4248 error
= memcg_online_kmem(memcg
);
4252 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4253 static_branch_inc(&memcg_sockets_enabled_key
);
4257 mem_cgroup_free(memcg
);
4258 return ERR_PTR(-ENOMEM
);
4261 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
4263 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4265 /* Online state pins memcg ID, memcg ID pins CSS */
4266 atomic_set(&memcg
->id
.ref
, 1);
4271 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
4273 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4274 struct mem_cgroup_event
*event
, *tmp
;
4277 * Unregister events and notify userspace.
4278 * Notify userspace about cgroup removing only after rmdir of cgroup
4279 * directory to avoid race between userspace and kernelspace.
4281 spin_lock(&memcg
->event_list_lock
);
4282 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
4283 list_del_init(&event
->list
);
4284 schedule_work(&event
->remove
);
4286 spin_unlock(&memcg
->event_list_lock
);
4288 memcg_offline_kmem(memcg
);
4289 wb_memcg_offline(memcg
);
4291 mem_cgroup_id_put(memcg
);
4294 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
4296 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4298 invalidate_reclaim_iterators(memcg
);
4301 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
4303 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4305 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4306 static_branch_dec(&memcg_sockets_enabled_key
);
4308 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
4309 static_branch_dec(&memcg_sockets_enabled_key
);
4311 vmpressure_cleanup(&memcg
->vmpressure
);
4312 cancel_work_sync(&memcg
->high_work
);
4313 mem_cgroup_remove_from_trees(memcg
);
4314 memcg_free_kmem(memcg
);
4315 mem_cgroup_free(memcg
);
4319 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4320 * @css: the target css
4322 * Reset the states of the mem_cgroup associated with @css. This is
4323 * invoked when the userland requests disabling on the default hierarchy
4324 * but the memcg is pinned through dependency. The memcg should stop
4325 * applying policies and should revert to the vanilla state as it may be
4326 * made visible again.
4328 * The current implementation only resets the essential configurations.
4329 * This needs to be expanded to cover all the visible parts.
4331 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
4333 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4335 page_counter_limit(&memcg
->memory
, PAGE_COUNTER_MAX
);
4336 page_counter_limit(&memcg
->swap
, PAGE_COUNTER_MAX
);
4337 page_counter_limit(&memcg
->memsw
, PAGE_COUNTER_MAX
);
4338 page_counter_limit(&memcg
->kmem
, PAGE_COUNTER_MAX
);
4339 page_counter_limit(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
4341 memcg
->high
= PAGE_COUNTER_MAX
;
4342 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4343 memcg_wb_domain_size_changed(memcg
);
4347 /* Handlers for move charge at task migration. */
4348 static int mem_cgroup_do_precharge(unsigned long count
)
4352 /* Try a single bulk charge without reclaim first, kswapd may wake */
4353 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
4355 mc
.precharge
+= count
;
4359 /* Try charges one by one with reclaim, but do not retry */
4361 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
4375 enum mc_target_type
{
4381 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
4382 unsigned long addr
, pte_t ptent
)
4384 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
4386 if (!page
|| !page_mapped(page
))
4388 if (PageAnon(page
)) {
4389 if (!(mc
.flags
& MOVE_ANON
))
4392 if (!(mc
.flags
& MOVE_FILE
))
4395 if (!get_page_unless_zero(page
))
4402 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4403 pte_t ptent
, swp_entry_t
*entry
)
4405 struct page
*page
= NULL
;
4406 swp_entry_t ent
= pte_to_swp_entry(ptent
);
4408 if (!(mc
.flags
& MOVE_ANON
) || non_swap_entry(ent
))
4411 * Because lookup_swap_cache() updates some statistics counter,
4412 * we call find_get_page() with swapper_space directly.
4414 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
4415 if (do_memsw_account())
4416 entry
->val
= ent
.val
;
4421 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4422 pte_t ptent
, swp_entry_t
*entry
)
4428 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
4429 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
4431 struct page
*page
= NULL
;
4432 struct address_space
*mapping
;
4435 if (!vma
->vm_file
) /* anonymous vma */
4437 if (!(mc
.flags
& MOVE_FILE
))
4440 mapping
= vma
->vm_file
->f_mapping
;
4441 pgoff
= linear_page_index(vma
, addr
);
4443 /* page is moved even if it's not RSS of this task(page-faulted). */
4445 /* shmem/tmpfs may report page out on swap: account for that too. */
4446 if (shmem_mapping(mapping
)) {
4447 page
= find_get_entry(mapping
, pgoff
);
4448 if (radix_tree_exceptional_entry(page
)) {
4449 swp_entry_t swp
= radix_to_swp_entry(page
);
4450 if (do_memsw_account())
4452 page
= find_get_page(swap_address_space(swp
),
4456 page
= find_get_page(mapping
, pgoff
);
4458 page
= find_get_page(mapping
, pgoff
);
4464 * mem_cgroup_move_account - move account of the page
4466 * @compound: charge the page as compound or small page
4467 * @from: mem_cgroup which the page is moved from.
4468 * @to: mem_cgroup which the page is moved to. @from != @to.
4470 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
4472 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
4475 static int mem_cgroup_move_account(struct page
*page
,
4477 struct mem_cgroup
*from
,
4478 struct mem_cgroup
*to
)
4480 unsigned long flags
;
4481 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
4485 VM_BUG_ON(from
== to
);
4486 VM_BUG_ON_PAGE(PageLRU(page
), page
);
4487 VM_BUG_ON(compound
&& !PageTransHuge(page
));
4490 * Prevent mem_cgroup_migrate() from looking at
4491 * page->mem_cgroup of its source page while we change it.
4494 if (!trylock_page(page
))
4498 if (page
->mem_cgroup
!= from
)
4501 anon
= PageAnon(page
);
4503 spin_lock_irqsave(&from
->move_lock
, flags
);
4505 if (!anon
&& page_mapped(page
)) {
4506 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
4508 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_FILE_MAPPED
],
4513 * move_lock grabbed above and caller set from->moving_account, so
4514 * mem_cgroup_update_page_stat() will serialize updates to PageDirty.
4515 * So mapping should be stable for dirty pages.
4517 if (!anon
&& PageDirty(page
)) {
4518 struct address_space
*mapping
= page_mapping(page
);
4520 if (mapping_cap_account_dirty(mapping
)) {
4521 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_DIRTY
],
4523 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_DIRTY
],
4528 if (PageWriteback(page
)) {
4529 __this_cpu_sub(from
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
4531 __this_cpu_add(to
->stat
->count
[MEM_CGROUP_STAT_WRITEBACK
],
4536 * It is safe to change page->mem_cgroup here because the page
4537 * is referenced, charged, and isolated - we can't race with
4538 * uncharging, charging, migration, or LRU putback.
4541 /* caller should have done css_get */
4542 page
->mem_cgroup
= to
;
4543 spin_unlock_irqrestore(&from
->move_lock
, flags
);
4547 local_irq_disable();
4548 mem_cgroup_charge_statistics(to
, page
, compound
, nr_pages
);
4549 memcg_check_events(to
, page
);
4550 mem_cgroup_charge_statistics(from
, page
, compound
, -nr_pages
);
4551 memcg_check_events(from
, page
);
4560 * get_mctgt_type - get target type of moving charge
4561 * @vma: the vma the pte to be checked belongs
4562 * @addr: the address corresponding to the pte to be checked
4563 * @ptent: the pte to be checked
4564 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4567 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4568 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4569 * move charge. if @target is not NULL, the page is stored in target->page
4570 * with extra refcnt got(Callers should handle it).
4571 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4572 * target for charge migration. if @target is not NULL, the entry is stored
4575 * Called with pte lock held.
4578 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
4579 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
4581 struct page
*page
= NULL
;
4582 enum mc_target_type ret
= MC_TARGET_NONE
;
4583 swp_entry_t ent
= { .val
= 0 };
4585 if (pte_present(ptent
))
4586 page
= mc_handle_present_pte(vma
, addr
, ptent
);
4587 else if (is_swap_pte(ptent
))
4588 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
4589 else if (pte_none(ptent
))
4590 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
4592 if (!page
&& !ent
.val
)
4596 * Do only loose check w/o serialization.
4597 * mem_cgroup_move_account() checks the page is valid or
4598 * not under LRU exclusion.
4600 if (page
->mem_cgroup
== mc
.from
) {
4601 ret
= MC_TARGET_PAGE
;
4603 target
->page
= page
;
4605 if (!ret
|| !target
)
4608 /* There is a swap entry and a page doesn't exist or isn't charged */
4609 if (ent
.val
&& !ret
&&
4610 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
4611 ret
= MC_TARGET_SWAP
;
4618 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4620 * We don't consider swapping or file mapped pages because THP does not
4621 * support them for now.
4622 * Caller should make sure that pmd_trans_huge(pmd) is true.
4624 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4625 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4627 struct page
*page
= NULL
;
4628 enum mc_target_type ret
= MC_TARGET_NONE
;
4630 page
= pmd_page(pmd
);
4631 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
4632 if (!(mc
.flags
& MOVE_ANON
))
4634 if (page
->mem_cgroup
== mc
.from
) {
4635 ret
= MC_TARGET_PAGE
;
4638 target
->page
= page
;
4644 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4645 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4647 return MC_TARGET_NONE
;
4651 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
4652 unsigned long addr
, unsigned long end
,
4653 struct mm_walk
*walk
)
4655 struct vm_area_struct
*vma
= walk
->vma
;
4659 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4661 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
4662 mc
.precharge
+= HPAGE_PMD_NR
;
4667 if (pmd_trans_unstable(pmd
))
4669 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4670 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
4671 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
4672 mc
.precharge
++; /* increment precharge temporarily */
4673 pte_unmap_unlock(pte
- 1, ptl
);
4679 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
4681 unsigned long precharge
;
4683 struct mm_walk mem_cgroup_count_precharge_walk
= {
4684 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
4687 down_read(&mm
->mmap_sem
);
4688 walk_page_range(0, mm
->highest_vm_end
,
4689 &mem_cgroup_count_precharge_walk
);
4690 up_read(&mm
->mmap_sem
);
4692 precharge
= mc
.precharge
;
4698 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
4700 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
4702 VM_BUG_ON(mc
.moving_task
);
4703 mc
.moving_task
= current
;
4704 return mem_cgroup_do_precharge(precharge
);
4707 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4708 static void __mem_cgroup_clear_mc(void)
4710 struct mem_cgroup
*from
= mc
.from
;
4711 struct mem_cgroup
*to
= mc
.to
;
4713 /* we must uncharge all the leftover precharges from mc.to */
4715 cancel_charge(mc
.to
, mc
.precharge
);
4719 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4720 * we must uncharge here.
4722 if (mc
.moved_charge
) {
4723 cancel_charge(mc
.from
, mc
.moved_charge
);
4724 mc
.moved_charge
= 0;
4726 /* we must fixup refcnts and charges */
4727 if (mc
.moved_swap
) {
4728 /* uncharge swap account from the old cgroup */
4729 if (!mem_cgroup_is_root(mc
.from
))
4730 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
4732 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
4735 * we charged both to->memory and to->memsw, so we
4736 * should uncharge to->memory.
4738 if (!mem_cgroup_is_root(mc
.to
))
4739 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
4741 mem_cgroup_id_get_many(mc
.to
, mc
.moved_swap
);
4742 css_put_many(&mc
.to
->css
, mc
.moved_swap
);
4746 memcg_oom_recover(from
);
4747 memcg_oom_recover(to
);
4748 wake_up_all(&mc
.waitq
);
4751 static void mem_cgroup_clear_mc(void)
4753 struct mm_struct
*mm
= mc
.mm
;
4756 * we must clear moving_task before waking up waiters at the end of
4759 mc
.moving_task
= NULL
;
4760 __mem_cgroup_clear_mc();
4761 spin_lock(&mc
.lock
);
4765 spin_unlock(&mc
.lock
);
4770 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
4772 struct cgroup_subsys_state
*css
;
4773 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
4774 struct mem_cgroup
*from
;
4775 struct task_struct
*leader
, *p
;
4776 struct mm_struct
*mm
;
4777 unsigned long move_flags
;
4780 /* charge immigration isn't supported on the default hierarchy */
4781 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
4785 * Multi-process migrations only happen on the default hierarchy
4786 * where charge immigration is not used. Perform charge
4787 * immigration if @tset contains a leader and whine if there are
4791 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
4794 memcg
= mem_cgroup_from_css(css
);
4800 * We are now commited to this value whatever it is. Changes in this
4801 * tunable will only affect upcoming migrations, not the current one.
4802 * So we need to save it, and keep it going.
4804 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
4808 from
= mem_cgroup_from_task(p
);
4810 VM_BUG_ON(from
== memcg
);
4812 mm
= get_task_mm(p
);
4815 /* We move charges only when we move a owner of the mm */
4816 if (mm
->owner
== p
) {
4819 VM_BUG_ON(mc
.precharge
);
4820 VM_BUG_ON(mc
.moved_charge
);
4821 VM_BUG_ON(mc
.moved_swap
);
4823 spin_lock(&mc
.lock
);
4827 mc
.flags
= move_flags
;
4828 spin_unlock(&mc
.lock
);
4829 /* We set mc.moving_task later */
4831 ret
= mem_cgroup_precharge_mc(mm
);
4833 mem_cgroup_clear_mc();
4840 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
4843 mem_cgroup_clear_mc();
4846 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
4847 unsigned long addr
, unsigned long end
,
4848 struct mm_walk
*walk
)
4851 struct vm_area_struct
*vma
= walk
->vma
;
4854 enum mc_target_type target_type
;
4855 union mc_target target
;
4858 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4860 if (mc
.precharge
< HPAGE_PMD_NR
) {
4864 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
4865 if (target_type
== MC_TARGET_PAGE
) {
4867 if (!isolate_lru_page(page
)) {
4868 if (!mem_cgroup_move_account(page
, true,
4870 mc
.precharge
-= HPAGE_PMD_NR
;
4871 mc
.moved_charge
+= HPAGE_PMD_NR
;
4873 putback_lru_page(page
);
4881 if (pmd_trans_unstable(pmd
))
4884 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4885 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
4886 pte_t ptent
= *(pte
++);
4892 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
4893 case MC_TARGET_PAGE
:
4896 * We can have a part of the split pmd here. Moving it
4897 * can be done but it would be too convoluted so simply
4898 * ignore such a partial THP and keep it in original
4899 * memcg. There should be somebody mapping the head.
4901 if (PageTransCompound(page
))
4903 if (isolate_lru_page(page
))
4905 if (!mem_cgroup_move_account(page
, false,
4908 /* we uncharge from mc.from later. */
4911 putback_lru_page(page
);
4912 put
: /* get_mctgt_type() gets the page */
4915 case MC_TARGET_SWAP
:
4917 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
4919 /* we fixup refcnts and charges later. */
4927 pte_unmap_unlock(pte
- 1, ptl
);
4932 * We have consumed all precharges we got in can_attach().
4933 * We try charge one by one, but don't do any additional
4934 * charges to mc.to if we have failed in charge once in attach()
4937 ret
= mem_cgroup_do_precharge(1);
4945 static void mem_cgroup_move_charge(void)
4947 struct mm_walk mem_cgroup_move_charge_walk
= {
4948 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
4952 lru_add_drain_all();
4954 * Signal lock_page_memcg() to take the memcg's move_lock
4955 * while we're moving its pages to another memcg. Then wait
4956 * for already started RCU-only updates to finish.
4958 atomic_inc(&mc
.from
->moving_account
);
4961 if (unlikely(!down_read_trylock(&mc
.mm
->mmap_sem
))) {
4963 * Someone who are holding the mmap_sem might be waiting in
4964 * waitq. So we cancel all extra charges, wake up all waiters,
4965 * and retry. Because we cancel precharges, we might not be able
4966 * to move enough charges, but moving charge is a best-effort
4967 * feature anyway, so it wouldn't be a big problem.
4969 __mem_cgroup_clear_mc();
4974 * When we have consumed all precharges and failed in doing
4975 * additional charge, the page walk just aborts.
4977 walk_page_range(0, mc
.mm
->highest_vm_end
, &mem_cgroup_move_charge_walk
);
4979 up_read(&mc
.mm
->mmap_sem
);
4980 atomic_dec(&mc
.from
->moving_account
);
4983 static void mem_cgroup_move_task(void)
4986 mem_cgroup_move_charge();
4987 mem_cgroup_clear_mc();
4990 #else /* !CONFIG_MMU */
4991 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
4995 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
4998 static void mem_cgroup_move_task(void)
5004 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5005 * to verify whether we're attached to the default hierarchy on each mount
5008 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5011 * use_hierarchy is forced on the default hierarchy. cgroup core
5012 * guarantees that @root doesn't have any children, so turning it
5013 * on for the root memcg is enough.
5015 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5016 root_mem_cgroup
->use_hierarchy
= true;
5018 root_mem_cgroup
->use_hierarchy
= false;
5021 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
5024 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5026 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
5029 static int memory_low_show(struct seq_file
*m
, void *v
)
5031 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5032 unsigned long low
= READ_ONCE(memcg
->low
);
5034 if (low
== PAGE_COUNTER_MAX
)
5035 seq_puts(m
, "max\n");
5037 seq_printf(m
, "%llu\n", (u64
)low
* PAGE_SIZE
);
5042 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
5043 char *buf
, size_t nbytes
, loff_t off
)
5045 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5049 buf
= strstrip(buf
);
5050 err
= page_counter_memparse(buf
, "max", &low
);
5059 static int memory_high_show(struct seq_file
*m
, void *v
)
5061 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5062 unsigned long high
= READ_ONCE(memcg
->high
);
5064 if (high
== PAGE_COUNTER_MAX
)
5065 seq_puts(m
, "max\n");
5067 seq_printf(m
, "%llu\n", (u64
)high
* PAGE_SIZE
);
5072 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
5073 char *buf
, size_t nbytes
, loff_t off
)
5075 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5076 unsigned long nr_pages
;
5080 buf
= strstrip(buf
);
5081 err
= page_counter_memparse(buf
, "max", &high
);
5087 nr_pages
= page_counter_read(&memcg
->memory
);
5088 if (nr_pages
> high
)
5089 try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
5092 memcg_wb_domain_size_changed(memcg
);
5096 static int memory_max_show(struct seq_file
*m
, void *v
)
5098 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5099 unsigned long max
= READ_ONCE(memcg
->memory
.limit
);
5101 if (max
== PAGE_COUNTER_MAX
)
5102 seq_puts(m
, "max\n");
5104 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
5109 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
5110 char *buf
, size_t nbytes
, loff_t off
)
5112 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5113 unsigned int nr_reclaims
= MEM_CGROUP_RECLAIM_RETRIES
;
5114 bool drained
= false;
5118 buf
= strstrip(buf
);
5119 err
= page_counter_memparse(buf
, "max", &max
);
5123 xchg(&memcg
->memory
.limit
, max
);
5126 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
5128 if (nr_pages
<= max
)
5131 if (signal_pending(current
)) {
5137 drain_all_stock(memcg
);
5143 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
5149 mem_cgroup_events(memcg
, MEMCG_OOM
, 1);
5150 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
5154 memcg_wb_domain_size_changed(memcg
);
5158 static int memory_events_show(struct seq_file
*m
, void *v
)
5160 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5162 seq_printf(m
, "low %lu\n", mem_cgroup_read_events(memcg
, MEMCG_LOW
));
5163 seq_printf(m
, "high %lu\n", mem_cgroup_read_events(memcg
, MEMCG_HIGH
));
5164 seq_printf(m
, "max %lu\n", mem_cgroup_read_events(memcg
, MEMCG_MAX
));
5165 seq_printf(m
, "oom %lu\n", mem_cgroup_read_events(memcg
, MEMCG_OOM
));
5170 static int memory_stat_show(struct seq_file
*m
, void *v
)
5172 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5173 unsigned long stat
[MEMCG_NR_STAT
];
5174 unsigned long events
[MEMCG_NR_EVENTS
];
5178 * Provide statistics on the state of the memory subsystem as
5179 * well as cumulative event counters that show past behavior.
5181 * This list is ordered following a combination of these gradients:
5182 * 1) generic big picture -> specifics and details
5183 * 2) reflecting userspace activity -> reflecting kernel heuristics
5185 * Current memory state:
5188 tree_stat(memcg
, stat
);
5189 tree_events(memcg
, events
);
5191 seq_printf(m
, "anon %llu\n",
5192 (u64
)stat
[MEM_CGROUP_STAT_RSS
] * PAGE_SIZE
);
5193 seq_printf(m
, "file %llu\n",
5194 (u64
)stat
[MEM_CGROUP_STAT_CACHE
] * PAGE_SIZE
);
5195 seq_printf(m
, "kernel_stack %llu\n",
5196 (u64
)stat
[MEMCG_KERNEL_STACK_KB
] * 1024);
5197 seq_printf(m
, "slab %llu\n",
5198 (u64
)(stat
[MEMCG_SLAB_RECLAIMABLE
] +
5199 stat
[MEMCG_SLAB_UNRECLAIMABLE
]) * PAGE_SIZE
);
5200 seq_printf(m
, "sock %llu\n",
5201 (u64
)stat
[MEMCG_SOCK
] * PAGE_SIZE
);
5203 seq_printf(m
, "file_mapped %llu\n",
5204 (u64
)stat
[MEM_CGROUP_STAT_FILE_MAPPED
] * PAGE_SIZE
);
5205 seq_printf(m
, "file_dirty %llu\n",
5206 (u64
)stat
[MEM_CGROUP_STAT_DIRTY
] * PAGE_SIZE
);
5207 seq_printf(m
, "file_writeback %llu\n",
5208 (u64
)stat
[MEM_CGROUP_STAT_WRITEBACK
] * PAGE_SIZE
);
5210 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5211 struct mem_cgroup
*mi
;
5212 unsigned long val
= 0;
5214 for_each_mem_cgroup_tree(mi
, memcg
)
5215 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
));
5216 seq_printf(m
, "%s %llu\n",
5217 mem_cgroup_lru_names
[i
], (u64
)val
* PAGE_SIZE
);
5220 seq_printf(m
, "slab_reclaimable %llu\n",
5221 (u64
)stat
[MEMCG_SLAB_RECLAIMABLE
] * PAGE_SIZE
);
5222 seq_printf(m
, "slab_unreclaimable %llu\n",
5223 (u64
)stat
[MEMCG_SLAB_UNRECLAIMABLE
] * PAGE_SIZE
);
5225 /* Accumulated memory events */
5227 seq_printf(m
, "pgfault %lu\n",
5228 events
[MEM_CGROUP_EVENTS_PGFAULT
]);
5229 seq_printf(m
, "pgmajfault %lu\n",
5230 events
[MEM_CGROUP_EVENTS_PGMAJFAULT
]);
5235 static struct cftype memory_files
[] = {
5238 .flags
= CFTYPE_NOT_ON_ROOT
,
5239 .read_u64
= memory_current_read
,
5243 .flags
= CFTYPE_NOT_ON_ROOT
,
5244 .seq_show
= memory_low_show
,
5245 .write
= memory_low_write
,
5249 .flags
= CFTYPE_NOT_ON_ROOT
,
5250 .seq_show
= memory_high_show
,
5251 .write
= memory_high_write
,
5255 .flags
= CFTYPE_NOT_ON_ROOT
,
5256 .seq_show
= memory_max_show
,
5257 .write
= memory_max_write
,
5261 .flags
= CFTYPE_NOT_ON_ROOT
,
5262 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
5263 .seq_show
= memory_events_show
,
5267 .flags
= CFTYPE_NOT_ON_ROOT
,
5268 .seq_show
= memory_stat_show
,
5273 struct cgroup_subsys memory_cgrp_subsys
= {
5274 .css_alloc
= mem_cgroup_css_alloc
,
5275 .css_online
= mem_cgroup_css_online
,
5276 .css_offline
= mem_cgroup_css_offline
,
5277 .css_released
= mem_cgroup_css_released
,
5278 .css_free
= mem_cgroup_css_free
,
5279 .css_reset
= mem_cgroup_css_reset
,
5280 .can_attach
= mem_cgroup_can_attach
,
5281 .cancel_attach
= mem_cgroup_cancel_attach
,
5282 .post_attach
= mem_cgroup_move_task
,
5283 .bind
= mem_cgroup_bind
,
5284 .dfl_cftypes
= memory_files
,
5285 .legacy_cftypes
= mem_cgroup_legacy_files
,
5290 * mem_cgroup_low - check if memory consumption is below the normal range
5291 * @root: the highest ancestor to consider
5292 * @memcg: the memory cgroup to check
5294 * Returns %true if memory consumption of @memcg, and that of all
5295 * configurable ancestors up to @root, is below the normal range.
5297 bool mem_cgroup_low(struct mem_cgroup
*root
, struct mem_cgroup
*memcg
)
5299 if (mem_cgroup_disabled())
5303 * The toplevel group doesn't have a configurable range, so
5304 * it's never low when looked at directly, and it is not
5305 * considered an ancestor when assessing the hierarchy.
5308 if (memcg
== root_mem_cgroup
)
5311 if (page_counter_read(&memcg
->memory
) >= memcg
->low
)
5314 while (memcg
!= root
) {
5315 memcg
= parent_mem_cgroup(memcg
);
5317 if (memcg
== root_mem_cgroup
)
5320 if (page_counter_read(&memcg
->memory
) >= memcg
->low
)
5327 * mem_cgroup_try_charge - try charging a page
5328 * @page: page to charge
5329 * @mm: mm context of the victim
5330 * @gfp_mask: reclaim mode
5331 * @memcgp: charged memcg return
5332 * @compound: charge the page as compound or small page
5334 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5335 * pages according to @gfp_mask if necessary.
5337 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5338 * Otherwise, an error code is returned.
5340 * After page->mapping has been set up, the caller must finalize the
5341 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5342 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5344 int mem_cgroup_try_charge(struct page
*page
, struct mm_struct
*mm
,
5345 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
,
5348 struct mem_cgroup
*memcg
= NULL
;
5349 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5352 if (mem_cgroup_disabled())
5355 if (PageSwapCache(page
)) {
5357 * Every swap fault against a single page tries to charge the
5358 * page, bail as early as possible. shmem_unuse() encounters
5359 * already charged pages, too. The USED bit is protected by
5360 * the page lock, which serializes swap cache removal, which
5361 * in turn serializes uncharging.
5363 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
5364 if (page
->mem_cgroup
)
5367 if (do_swap_account
) {
5368 swp_entry_t ent
= { .val
= page_private(page
), };
5369 unsigned short id
= lookup_swap_cgroup_id(ent
);
5372 memcg
= mem_cgroup_from_id(id
);
5373 if (memcg
&& !css_tryget_online(&memcg
->css
))
5380 memcg
= get_mem_cgroup_from_mm(mm
);
5382 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
5384 css_put(&memcg
->css
);
5391 * mem_cgroup_commit_charge - commit a page charge
5392 * @page: page to charge
5393 * @memcg: memcg to charge the page to
5394 * @lrucare: page might be on LRU already
5395 * @compound: charge the page as compound or small page
5397 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5398 * after page->mapping has been set up. This must happen atomically
5399 * as part of the page instantiation, i.e. under the page table lock
5400 * for anonymous pages, under the page lock for page and swap cache.
5402 * In addition, the page must not be on the LRU during the commit, to
5403 * prevent racing with task migration. If it might be, use @lrucare.
5405 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5407 void mem_cgroup_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5408 bool lrucare
, bool compound
)
5410 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5412 VM_BUG_ON_PAGE(!page
->mapping
, page
);
5413 VM_BUG_ON_PAGE(PageLRU(page
) && !lrucare
, page
);
5415 if (mem_cgroup_disabled())
5418 * Swap faults will attempt to charge the same page multiple
5419 * times. But reuse_swap_page() might have removed the page
5420 * from swapcache already, so we can't check PageSwapCache().
5425 commit_charge(page
, memcg
, lrucare
);
5427 local_irq_disable();
5428 mem_cgroup_charge_statistics(memcg
, page
, compound
, nr_pages
);
5429 memcg_check_events(memcg
, page
);
5432 if (do_memsw_account() && PageSwapCache(page
)) {
5433 swp_entry_t entry
= { .val
= page_private(page
) };
5435 * The swap entry might not get freed for a long time,
5436 * let's not wait for it. The page already received a
5437 * memory+swap charge, drop the swap entry duplicate.
5439 mem_cgroup_uncharge_swap(entry
);
5444 * mem_cgroup_cancel_charge - cancel a page charge
5445 * @page: page to charge
5446 * @memcg: memcg to charge the page to
5447 * @compound: charge the page as compound or small page
5449 * Cancel a charge transaction started by mem_cgroup_try_charge().
5451 void mem_cgroup_cancel_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5454 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5456 if (mem_cgroup_disabled())
5459 * Swap faults will attempt to charge the same page multiple
5460 * times. But reuse_swap_page() might have removed the page
5461 * from swapcache already, so we can't check PageSwapCache().
5466 cancel_charge(memcg
, nr_pages
);
5469 static void uncharge_batch(struct mem_cgroup
*memcg
, unsigned long pgpgout
,
5470 unsigned long nr_anon
, unsigned long nr_file
,
5471 unsigned long nr_huge
, unsigned long nr_kmem
,
5472 struct page
*dummy_page
)
5474 unsigned long nr_pages
= nr_anon
+ nr_file
+ nr_kmem
;
5475 unsigned long flags
;
5477 if (!mem_cgroup_is_root(memcg
)) {
5478 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5479 if (do_memsw_account())
5480 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
5481 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && nr_kmem
)
5482 page_counter_uncharge(&memcg
->kmem
, nr_kmem
);
5483 memcg_oom_recover(memcg
);
5486 local_irq_save(flags
);
5487 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS
], nr_anon
);
5488 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_CACHE
], nr_file
);
5489 __this_cpu_sub(memcg
->stat
->count
[MEM_CGROUP_STAT_RSS_HUGE
], nr_huge
);
5490 __this_cpu_add(memcg
->stat
->events
[MEM_CGROUP_EVENTS_PGPGOUT
], pgpgout
);
5491 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
5492 memcg_check_events(memcg
, dummy_page
);
5493 local_irq_restore(flags
);
5495 if (!mem_cgroup_is_root(memcg
))
5496 css_put_many(&memcg
->css
, nr_pages
);
5499 static void uncharge_list(struct list_head
*page_list
)
5501 struct mem_cgroup
*memcg
= NULL
;
5502 unsigned long nr_anon
= 0;
5503 unsigned long nr_file
= 0;
5504 unsigned long nr_huge
= 0;
5505 unsigned long nr_kmem
= 0;
5506 unsigned long pgpgout
= 0;
5507 struct list_head
*next
;
5511 * Note that the list can be a single page->lru; hence the
5512 * do-while loop instead of a simple list_for_each_entry().
5514 next
= page_list
->next
;
5516 page
= list_entry(next
, struct page
, lru
);
5517 next
= page
->lru
.next
;
5519 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5520 VM_BUG_ON_PAGE(page_count(page
), page
);
5522 if (!page
->mem_cgroup
)
5526 * Nobody should be changing or seriously looking at
5527 * page->mem_cgroup at this point, we have fully
5528 * exclusive access to the page.
5531 if (memcg
!= page
->mem_cgroup
) {
5533 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5534 nr_huge
, nr_kmem
, page
);
5535 pgpgout
= nr_anon
= nr_file
=
5536 nr_huge
= nr_kmem
= 0;
5538 memcg
= page
->mem_cgroup
;
5541 if (!PageKmemcg(page
)) {
5542 unsigned int nr_pages
= 1;
5544 if (PageTransHuge(page
)) {
5545 nr_pages
<<= compound_order(page
);
5546 nr_huge
+= nr_pages
;
5549 nr_anon
+= nr_pages
;
5551 nr_file
+= nr_pages
;
5554 nr_kmem
+= 1 << compound_order(page
);
5555 __ClearPageKmemcg(page
);
5558 page
->mem_cgroup
= NULL
;
5559 } while (next
!= page_list
);
5562 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5563 nr_huge
, nr_kmem
, page
);
5567 * mem_cgroup_uncharge - uncharge a page
5568 * @page: page to uncharge
5570 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5571 * mem_cgroup_commit_charge().
5573 void mem_cgroup_uncharge(struct page
*page
)
5575 if (mem_cgroup_disabled())
5578 /* Don't touch page->lru of any random page, pre-check: */
5579 if (!page
->mem_cgroup
)
5582 INIT_LIST_HEAD(&page
->lru
);
5583 uncharge_list(&page
->lru
);
5587 * mem_cgroup_uncharge_list - uncharge a list of page
5588 * @page_list: list of pages to uncharge
5590 * Uncharge a list of pages previously charged with
5591 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5593 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
5595 if (mem_cgroup_disabled())
5598 if (!list_empty(page_list
))
5599 uncharge_list(page_list
);
5603 * mem_cgroup_migrate - charge a page's replacement
5604 * @oldpage: currently circulating page
5605 * @newpage: replacement page
5607 * Charge @newpage as a replacement page for @oldpage. @oldpage will
5608 * be uncharged upon free.
5610 * Both pages must be locked, @newpage->mapping must be set up.
5612 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
5614 struct mem_cgroup
*memcg
;
5615 unsigned int nr_pages
;
5617 unsigned long flags
;
5619 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
5620 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
5621 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
5622 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
5625 if (mem_cgroup_disabled())
5628 /* Page cache replacement: new page already charged? */
5629 if (newpage
->mem_cgroup
)
5632 /* Swapcache readahead pages can get replaced before being charged */
5633 memcg
= oldpage
->mem_cgroup
;
5637 /* Force-charge the new page. The old one will be freed soon */
5638 compound
= PageTransHuge(newpage
);
5639 nr_pages
= compound
? hpage_nr_pages(newpage
) : 1;
5641 page_counter_charge(&memcg
->memory
, nr_pages
);
5642 if (do_memsw_account())
5643 page_counter_charge(&memcg
->memsw
, nr_pages
);
5644 css_get_many(&memcg
->css
, nr_pages
);
5646 commit_charge(newpage
, memcg
, false);
5648 local_irq_save(flags
);
5649 mem_cgroup_charge_statistics(memcg
, newpage
, compound
, nr_pages
);
5650 memcg_check_events(memcg
, newpage
);
5651 local_irq_restore(flags
);
5654 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
5655 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
5657 void mem_cgroup_sk_alloc(struct sock
*sk
)
5659 struct mem_cgroup
*memcg
;
5661 if (!mem_cgroup_sockets_enabled
)
5665 * Socket cloning can throw us here with sk_memcg already
5666 * filled. It won't however, necessarily happen from
5667 * process context. So the test for root memcg given
5668 * the current task's memcg won't help us in this case.
5670 * Respecting the original socket's memcg is a better
5671 * decision in this case.
5674 BUG_ON(mem_cgroup_is_root(sk
->sk_memcg
));
5675 css_get(&sk
->sk_memcg
->css
);
5680 memcg
= mem_cgroup_from_task(current
);
5681 if (memcg
== root_mem_cgroup
)
5683 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
5685 if (css_tryget_online(&memcg
->css
))
5686 sk
->sk_memcg
= memcg
;
5691 void mem_cgroup_sk_free(struct sock
*sk
)
5694 css_put(&sk
->sk_memcg
->css
);
5698 * mem_cgroup_charge_skmem - charge socket memory
5699 * @memcg: memcg to charge
5700 * @nr_pages: number of pages to charge
5702 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
5703 * @memcg's configured limit, %false if the charge had to be forced.
5705 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5707 gfp_t gfp_mask
= GFP_KERNEL
;
5709 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5710 struct page_counter
*fail
;
5712 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
5713 memcg
->tcpmem_pressure
= 0;
5716 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
5717 memcg
->tcpmem_pressure
= 1;
5721 /* Don't block in the packet receive path */
5723 gfp_mask
= GFP_NOWAIT
;
5725 this_cpu_add(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5727 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
5730 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
5735 * mem_cgroup_uncharge_skmem - uncharge socket memory
5736 * @memcg - memcg to uncharge
5737 * @nr_pages - number of pages to uncharge
5739 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5741 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5742 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
5746 this_cpu_sub(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5748 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5749 css_put_many(&memcg
->css
, nr_pages
);
5752 static int __init
cgroup_memory(char *s
)
5756 while ((token
= strsep(&s
, ",")) != NULL
) {
5759 if (!strcmp(token
, "nosocket"))
5760 cgroup_memory_nosocket
= true;
5761 if (!strcmp(token
, "nokmem"))
5762 cgroup_memory_nokmem
= true;
5766 __setup("cgroup.memory=", cgroup_memory
);
5769 * subsys_initcall() for memory controller.
5771 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
5772 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
5773 * basically everything that doesn't depend on a specific mem_cgroup structure
5774 * should be initialized from here.
5776 static int __init
mem_cgroup_init(void)
5782 * Kmem cache creation is mostly done with the slab_mutex held,
5783 * so use a workqueue with limited concurrency to avoid stalling
5784 * all worker threads in case lots of cgroups are created and
5785 * destroyed simultaneously.
5787 memcg_kmem_cache_wq
= alloc_workqueue("memcg_kmem_cache", 0, 1);
5788 BUG_ON(!memcg_kmem_cache_wq
);
5791 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
5792 memcg_hotplug_cpu_dead
);
5794 for_each_possible_cpu(cpu
)
5795 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
5798 for_each_node(node
) {
5799 struct mem_cgroup_tree_per_node
*rtpn
;
5801 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
5802 node_online(node
) ? node
: NUMA_NO_NODE
);
5804 rtpn
->rb_root
= RB_ROOT
;
5805 spin_lock_init(&rtpn
->lock
);
5806 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
5811 subsys_initcall(mem_cgroup_init
);
5813 #ifdef CONFIG_MEMCG_SWAP
5814 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
5816 while (!atomic_inc_not_zero(&memcg
->id
.ref
)) {
5818 * The root cgroup cannot be destroyed, so it's refcount must
5821 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
5825 memcg
= parent_mem_cgroup(memcg
);
5827 memcg
= root_mem_cgroup
;
5833 * mem_cgroup_swapout - transfer a memsw charge to swap
5834 * @page: page whose memsw charge to transfer
5835 * @entry: swap entry to move the charge to
5837 * Transfer the memsw charge of @page to @entry.
5839 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
5841 struct mem_cgroup
*memcg
, *swap_memcg
;
5842 unsigned short oldid
;
5844 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5845 VM_BUG_ON_PAGE(page_count(page
), page
);
5847 if (!do_memsw_account())
5850 memcg
= page
->mem_cgroup
;
5852 /* Readahead page, never charged */
5857 * In case the memcg owning these pages has been offlined and doesn't
5858 * have an ID allocated to it anymore, charge the closest online
5859 * ancestor for the swap instead and transfer the memory+swap charge.
5861 swap_memcg
= mem_cgroup_id_get_online(memcg
);
5862 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
));
5863 VM_BUG_ON_PAGE(oldid
, page
);
5864 mem_cgroup_swap_statistics(swap_memcg
, true);
5866 page
->mem_cgroup
= NULL
;
5868 if (!mem_cgroup_is_root(memcg
))
5869 page_counter_uncharge(&memcg
->memory
, 1);
5871 if (memcg
!= swap_memcg
) {
5872 if (!mem_cgroup_is_root(swap_memcg
))
5873 page_counter_charge(&swap_memcg
->memsw
, 1);
5874 page_counter_uncharge(&memcg
->memsw
, 1);
5878 * Interrupts should be disabled here because the caller holds the
5879 * mapping->tree_lock lock which is taken with interrupts-off. It is
5880 * important here to have the interrupts disabled because it is the
5881 * only synchronisation we have for udpating the per-CPU variables.
5883 VM_BUG_ON(!irqs_disabled());
5884 mem_cgroup_charge_statistics(memcg
, page
, false, -1);
5885 memcg_check_events(memcg
, page
);
5887 if (!mem_cgroup_is_root(memcg
))
5888 css_put(&memcg
->css
);
5892 * mem_cgroup_try_charge_swap - try charging a swap entry
5893 * @page: page being added to swap
5894 * @entry: swap entry to charge
5896 * Try to charge @entry to the memcg that @page belongs to.
5898 * Returns 0 on success, -ENOMEM on failure.
5900 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
5902 struct mem_cgroup
*memcg
;
5903 struct page_counter
*counter
;
5904 unsigned short oldid
;
5906 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) || !do_swap_account
)
5909 memcg
= page
->mem_cgroup
;
5911 /* Readahead page, never charged */
5915 memcg
= mem_cgroup_id_get_online(memcg
);
5917 if (!mem_cgroup_is_root(memcg
) &&
5918 !page_counter_try_charge(&memcg
->swap
, 1, &counter
)) {
5919 mem_cgroup_id_put(memcg
);
5923 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
));
5924 VM_BUG_ON_PAGE(oldid
, page
);
5925 mem_cgroup_swap_statistics(memcg
, true);
5931 * mem_cgroup_uncharge_swap - uncharge a swap entry
5932 * @entry: swap entry to uncharge
5934 * Drop the swap charge associated with @entry.
5936 void mem_cgroup_uncharge_swap(swp_entry_t entry
)
5938 struct mem_cgroup
*memcg
;
5941 if (!do_swap_account
)
5944 id
= swap_cgroup_record(entry
, 0);
5946 memcg
= mem_cgroup_from_id(id
);
5948 if (!mem_cgroup_is_root(memcg
)) {
5949 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5950 page_counter_uncharge(&memcg
->swap
, 1);
5952 page_counter_uncharge(&memcg
->memsw
, 1);
5954 mem_cgroup_swap_statistics(memcg
, false);
5955 mem_cgroup_id_put(memcg
);
5960 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
5962 long nr_swap_pages
= get_nr_swap_pages();
5964 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5965 return nr_swap_pages
;
5966 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
5967 nr_swap_pages
= min_t(long, nr_swap_pages
,
5968 READ_ONCE(memcg
->swap
.limit
) -
5969 page_counter_read(&memcg
->swap
));
5970 return nr_swap_pages
;
5973 bool mem_cgroup_swap_full(struct page
*page
)
5975 struct mem_cgroup
*memcg
;
5977 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
5981 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5984 memcg
= page
->mem_cgroup
;
5988 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
5989 if (page_counter_read(&memcg
->swap
) * 2 >= memcg
->swap
.limit
)
5995 /* for remember boot option*/
5996 #ifdef CONFIG_MEMCG_SWAP_ENABLED
5997 static int really_do_swap_account __initdata
= 1;
5999 static int really_do_swap_account __initdata
;
6002 static int __init
enable_swap_account(char *s
)
6004 if (!strcmp(s
, "1"))
6005 really_do_swap_account
= 1;
6006 else if (!strcmp(s
, "0"))
6007 really_do_swap_account
= 0;
6010 __setup("swapaccount=", enable_swap_account
);
6012 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
6015 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6017 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
6020 static int swap_max_show(struct seq_file
*m
, void *v
)
6022 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
6023 unsigned long max
= READ_ONCE(memcg
->swap
.limit
);
6025 if (max
== PAGE_COUNTER_MAX
)
6026 seq_puts(m
, "max\n");
6028 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
6033 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
6034 char *buf
, size_t nbytes
, loff_t off
)
6036 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6040 buf
= strstrip(buf
);
6041 err
= page_counter_memparse(buf
, "max", &max
);
6045 mutex_lock(&memcg_limit_mutex
);
6046 err
= page_counter_limit(&memcg
->swap
, max
);
6047 mutex_unlock(&memcg_limit_mutex
);
6054 static struct cftype swap_files
[] = {
6056 .name
= "swap.current",
6057 .flags
= CFTYPE_NOT_ON_ROOT
,
6058 .read_u64
= swap_current_read
,
6062 .flags
= CFTYPE_NOT_ON_ROOT
,
6063 .seq_show
= swap_max_show
,
6064 .write
= swap_max_write
,
6069 static struct cftype memsw_cgroup_files
[] = {
6071 .name
= "memsw.usage_in_bytes",
6072 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6073 .read_u64
= mem_cgroup_read_u64
,
6076 .name
= "memsw.max_usage_in_bytes",
6077 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6078 .write
= mem_cgroup_reset
,
6079 .read_u64
= mem_cgroup_read_u64
,
6082 .name
= "memsw.limit_in_bytes",
6083 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6084 .write
= mem_cgroup_write
,
6085 .read_u64
= mem_cgroup_read_u64
,
6088 .name
= "memsw.failcnt",
6089 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6090 .write
= mem_cgroup_reset
,
6091 .read_u64
= mem_cgroup_read_u64
,
6093 { }, /* terminate */
6096 static int __init
mem_cgroup_swap_init(void)
6098 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6099 do_swap_account
= 1;
6100 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
,
6102 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
,
6103 memsw_cgroup_files
));
6107 subsys_initcall(mem_cgroup_swap_init
);
6109 #endif /* CONFIG_MEMCG_SWAP */