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_lru_names
[] = {
111 #define THRESHOLDS_EVENTS_TARGET 128
112 #define SOFTLIMIT_EVENTS_TARGET 1024
113 #define NUMAINFO_EVENTS_TARGET 1024
116 * Cgroups above their limits are maintained in a RB-Tree, independent of
117 * their hierarchy representation
120 struct mem_cgroup_tree_per_node
{
121 struct rb_root rb_root
;
125 struct mem_cgroup_tree
{
126 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
129 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
132 struct mem_cgroup_eventfd_list
{
133 struct list_head list
;
134 struct eventfd_ctx
*eventfd
;
138 * cgroup_event represents events which userspace want to receive.
140 struct mem_cgroup_event
{
142 * memcg which the event belongs to.
144 struct mem_cgroup
*memcg
;
146 * eventfd to signal userspace about the event.
148 struct eventfd_ctx
*eventfd
;
150 * Each of these stored in a list by the cgroup.
152 struct list_head list
;
154 * register_event() callback will be used to add new userspace
155 * waiter for changes related to this event. Use eventfd_signal()
156 * on eventfd to send notification to userspace.
158 int (*register_event
)(struct mem_cgroup
*memcg
,
159 struct eventfd_ctx
*eventfd
, const char *args
);
161 * unregister_event() callback will be called when userspace closes
162 * the eventfd or on cgroup removing. This callback must be set,
163 * if you want provide notification functionality.
165 void (*unregister_event
)(struct mem_cgroup
*memcg
,
166 struct eventfd_ctx
*eventfd
);
168 * All fields below needed to unregister event when
169 * userspace closes eventfd.
172 wait_queue_head_t
*wqh
;
173 wait_queue_entry_t wait
;
174 struct work_struct remove
;
177 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
178 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
180 /* Stuffs for move charges at task migration. */
182 * Types of charges to be moved.
184 #define MOVE_ANON 0x1U
185 #define MOVE_FILE 0x2U
186 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
188 /* "mc" and its members are protected by cgroup_mutex */
189 static struct move_charge_struct
{
190 spinlock_t lock
; /* for from, to */
191 struct mm_struct
*mm
;
192 struct mem_cgroup
*from
;
193 struct mem_cgroup
*to
;
195 unsigned long precharge
;
196 unsigned long moved_charge
;
197 unsigned long moved_swap
;
198 struct task_struct
*moving_task
; /* a task moving charges */
199 wait_queue_head_t waitq
; /* a waitq for other context */
201 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
202 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
206 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
207 * limit reclaim to prevent infinite loops, if they ever occur.
209 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
210 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
213 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
214 MEM_CGROUP_CHARGE_TYPE_ANON
,
215 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
216 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
220 /* for encoding cft->private value on file */
229 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
230 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
231 #define MEMFILE_ATTR(val) ((val) & 0xffff)
232 /* Used for OOM nofiier */
233 #define OOM_CONTROL (0)
235 /* Some nice accessors for the vmpressure. */
236 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
239 memcg
= root_mem_cgroup
;
240 return &memcg
->vmpressure
;
243 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
245 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
248 static inline bool mem_cgroup_is_root(struct mem_cgroup
*memcg
)
250 return (memcg
== root_mem_cgroup
);
255 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
256 * The main reason for not using cgroup id for this:
257 * this works better in sparse environments, where we have a lot of memcgs,
258 * but only a few kmem-limited. Or also, if we have, for instance, 200
259 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
260 * 200 entry array for that.
262 * The current size of the caches array is stored in memcg_nr_cache_ids. It
263 * will double each time we have to increase it.
265 static DEFINE_IDA(memcg_cache_ida
);
266 int memcg_nr_cache_ids
;
268 /* Protects memcg_nr_cache_ids */
269 static DECLARE_RWSEM(memcg_cache_ids_sem
);
271 void memcg_get_cache_ids(void)
273 down_read(&memcg_cache_ids_sem
);
276 void memcg_put_cache_ids(void)
278 up_read(&memcg_cache_ids_sem
);
282 * MIN_SIZE is different than 1, because we would like to avoid going through
283 * the alloc/free process all the time. In a small machine, 4 kmem-limited
284 * cgroups is a reasonable guess. In the future, it could be a parameter or
285 * tunable, but that is strictly not necessary.
287 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
288 * this constant directly from cgroup, but it is understandable that this is
289 * better kept as an internal representation in cgroup.c. In any case, the
290 * cgrp_id space is not getting any smaller, and we don't have to necessarily
291 * increase ours as well if it increases.
293 #define MEMCG_CACHES_MIN_SIZE 4
294 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
297 * A lot of the calls to the cache allocation functions are expected to be
298 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
299 * conditional to this static branch, we'll have to allow modules that does
300 * kmem_cache_alloc and the such to see this symbol as well
302 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
303 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
305 struct workqueue_struct
*memcg_kmem_cache_wq
;
307 #endif /* !CONFIG_SLOB */
310 * mem_cgroup_css_from_page - css of the memcg associated with a page
311 * @page: page of interest
313 * If memcg is bound to the default hierarchy, css of the memcg associated
314 * with @page is returned. The returned css remains associated with @page
315 * until it is released.
317 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
320 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
322 struct mem_cgroup
*memcg
;
324 memcg
= page
->mem_cgroup
;
326 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
327 memcg
= root_mem_cgroup
;
333 * page_cgroup_ino - return inode number of the memcg a page is charged to
336 * Look up the closest online ancestor of the memory cgroup @page is charged to
337 * and return its inode number or 0 if @page is not charged to any cgroup. It
338 * is safe to call this function without holding a reference to @page.
340 * Note, this function is inherently racy, because there is nothing to prevent
341 * the cgroup inode from getting torn down and potentially reallocated a moment
342 * after page_cgroup_ino() returns, so it only should be used by callers that
343 * do not care (such as procfs interfaces).
345 ino_t
page_cgroup_ino(struct page
*page
)
347 struct mem_cgroup
*memcg
;
348 unsigned long ino
= 0;
351 memcg
= READ_ONCE(page
->mem_cgroup
);
352 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
353 memcg
= parent_mem_cgroup(memcg
);
355 ino
= cgroup_ino(memcg
->css
.cgroup
);
360 static struct mem_cgroup_per_node
*
361 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
363 int nid
= page_to_nid(page
);
365 return memcg
->nodeinfo
[nid
];
368 static struct mem_cgroup_tree_per_node
*
369 soft_limit_tree_node(int nid
)
371 return soft_limit_tree
.rb_tree_per_node
[nid
];
374 static struct mem_cgroup_tree_per_node
*
375 soft_limit_tree_from_page(struct page
*page
)
377 int nid
= page_to_nid(page
);
379 return soft_limit_tree
.rb_tree_per_node
[nid
];
382 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
383 struct mem_cgroup_tree_per_node
*mctz
,
384 unsigned long new_usage_in_excess
)
386 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
387 struct rb_node
*parent
= NULL
;
388 struct mem_cgroup_per_node
*mz_node
;
393 mz
->usage_in_excess
= new_usage_in_excess
;
394 if (!mz
->usage_in_excess
)
398 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
400 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
)
403 * We can't avoid mem cgroups that are over their soft
404 * limit by the same amount
406 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
409 rb_link_node(&mz
->tree_node
, parent
, p
);
410 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
414 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
415 struct mem_cgroup_tree_per_node
*mctz
)
419 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
423 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
424 struct mem_cgroup_tree_per_node
*mctz
)
428 spin_lock_irqsave(&mctz
->lock
, flags
);
429 __mem_cgroup_remove_exceeded(mz
, mctz
);
430 spin_unlock_irqrestore(&mctz
->lock
, flags
);
433 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
435 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
436 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
437 unsigned long excess
= 0;
439 if (nr_pages
> soft_limit
)
440 excess
= nr_pages
- soft_limit
;
445 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
447 unsigned long excess
;
448 struct mem_cgroup_per_node
*mz
;
449 struct mem_cgroup_tree_per_node
*mctz
;
451 mctz
= soft_limit_tree_from_page(page
);
455 * Necessary to update all ancestors when hierarchy is used.
456 * because their event counter is not touched.
458 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
459 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
460 excess
= soft_limit_excess(memcg
);
462 * We have to update the tree if mz is on RB-tree or
463 * mem is over its softlimit.
465 if (excess
|| mz
->on_tree
) {
468 spin_lock_irqsave(&mctz
->lock
, flags
);
469 /* if on-tree, remove it */
471 __mem_cgroup_remove_exceeded(mz
, mctz
);
473 * Insert again. mz->usage_in_excess will be updated.
474 * If excess is 0, no tree ops.
476 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
477 spin_unlock_irqrestore(&mctz
->lock
, flags
);
482 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
484 struct mem_cgroup_tree_per_node
*mctz
;
485 struct mem_cgroup_per_node
*mz
;
489 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
490 mctz
= soft_limit_tree_node(nid
);
492 mem_cgroup_remove_exceeded(mz
, mctz
);
496 static struct mem_cgroup_per_node
*
497 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
499 struct rb_node
*rightmost
= NULL
;
500 struct mem_cgroup_per_node
*mz
;
504 rightmost
= rb_last(&mctz
->rb_root
);
506 goto done
; /* Nothing to reclaim from */
508 mz
= rb_entry(rightmost
, struct mem_cgroup_per_node
, tree_node
);
510 * Remove the node now but someone else can add it back,
511 * we will to add it back at the end of reclaim to its correct
512 * position in the tree.
514 __mem_cgroup_remove_exceeded(mz
, mctz
);
515 if (!soft_limit_excess(mz
->memcg
) ||
516 !css_tryget_online(&mz
->memcg
->css
))
522 static struct mem_cgroup_per_node
*
523 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
525 struct mem_cgroup_per_node
*mz
;
527 spin_lock_irq(&mctz
->lock
);
528 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
529 spin_unlock_irq(&mctz
->lock
);
534 * Return page count for single (non recursive) @memcg.
536 * Implementation Note: reading percpu statistics for memcg.
538 * Both of vmstat[] and percpu_counter has threshold and do periodic
539 * synchronization to implement "quick" read. There are trade-off between
540 * reading cost and precision of value. Then, we may have a chance to implement
541 * a periodic synchronization of counter in memcg's counter.
543 * But this _read() function is used for user interface now. The user accounts
544 * memory usage by memory cgroup and he _always_ requires exact value because
545 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
546 * have to visit all online cpus and make sum. So, for now, unnecessary
547 * synchronization is not implemented. (just implemented for cpu hotplug)
549 * If there are kernel internal actions which can make use of some not-exact
550 * value, and reading all cpu value can be performance bottleneck in some
551 * common workload, threshold and synchronization as vmstat[] should be
554 * The parameter idx can be of type enum memcg_event_item or vm_event_item.
557 static unsigned long memcg_sum_events(struct mem_cgroup
*memcg
,
560 unsigned long val
= 0;
563 for_each_possible_cpu(cpu
)
564 val
+= per_cpu(memcg
->stat
->events
[event
], cpu
);
568 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
570 bool compound
, int nr_pages
)
573 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
574 * counted as CACHE even if it's on ANON LRU.
577 __this_cpu_add(memcg
->stat
->count
[MEMCG_RSS
], nr_pages
);
579 __this_cpu_add(memcg
->stat
->count
[MEMCG_CACHE
], nr_pages
);
580 if (PageSwapBacked(page
))
581 __this_cpu_add(memcg
->stat
->count
[NR_SHMEM
], nr_pages
);
585 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
586 __this_cpu_add(memcg
->stat
->count
[MEMCG_RSS_HUGE
], nr_pages
);
589 /* pagein of a big page is an event. So, ignore page size */
591 __this_cpu_inc(memcg
->stat
->events
[PGPGIN
]);
593 __this_cpu_inc(memcg
->stat
->events
[PGPGOUT
]);
594 nr_pages
= -nr_pages
; /* for event */
597 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
600 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
601 int nid
, unsigned int lru_mask
)
603 struct lruvec
*lruvec
= mem_cgroup_lruvec(NODE_DATA(nid
), memcg
);
604 unsigned long nr
= 0;
607 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
610 if (!(BIT(lru
) & lru_mask
))
612 nr
+= mem_cgroup_get_lru_size(lruvec
, lru
);
617 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
618 unsigned int lru_mask
)
620 unsigned long nr
= 0;
623 for_each_node_state(nid
, N_MEMORY
)
624 nr
+= mem_cgroup_node_nr_lru_pages(memcg
, nid
, lru_mask
);
628 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
629 enum mem_cgroup_events_target target
)
631 unsigned long val
, next
;
633 val
= __this_cpu_read(memcg
->stat
->nr_page_events
);
634 next
= __this_cpu_read(memcg
->stat
->targets
[target
]);
635 /* from time_after() in jiffies.h */
636 if ((long)(next
- val
) < 0) {
638 case MEM_CGROUP_TARGET_THRESH
:
639 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
641 case MEM_CGROUP_TARGET_SOFTLIMIT
:
642 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
644 case MEM_CGROUP_TARGET_NUMAINFO
:
645 next
= val
+ NUMAINFO_EVENTS_TARGET
;
650 __this_cpu_write(memcg
->stat
->targets
[target
], next
);
657 * Check events in order.
660 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
662 /* threshold event is triggered in finer grain than soft limit */
663 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
664 MEM_CGROUP_TARGET_THRESH
))) {
666 bool do_numainfo __maybe_unused
;
668 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
669 MEM_CGROUP_TARGET_SOFTLIMIT
);
671 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
672 MEM_CGROUP_TARGET_NUMAINFO
);
674 mem_cgroup_threshold(memcg
);
675 if (unlikely(do_softlimit
))
676 mem_cgroup_update_tree(memcg
, page
);
678 if (unlikely(do_numainfo
))
679 atomic_inc(&memcg
->numainfo_events
);
684 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
687 * mm_update_next_owner() may clear mm->owner to NULL
688 * if it races with swapoff, page migration, etc.
689 * So this can be called with p == NULL.
694 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
696 EXPORT_SYMBOL(mem_cgroup_from_task
);
698 static struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
700 struct mem_cgroup
*memcg
= NULL
;
705 * Page cache insertions can happen withou an
706 * actual mm context, e.g. during disk probing
707 * on boot, loopback IO, acct() writes etc.
710 memcg
= root_mem_cgroup
;
712 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
713 if (unlikely(!memcg
))
714 memcg
= root_mem_cgroup
;
716 } while (!css_tryget_online(&memcg
->css
));
722 * mem_cgroup_iter - iterate over memory cgroup hierarchy
723 * @root: hierarchy root
724 * @prev: previously returned memcg, NULL on first invocation
725 * @reclaim: cookie for shared reclaim walks, NULL for full walks
727 * Returns references to children of the hierarchy below @root, or
728 * @root itself, or %NULL after a full round-trip.
730 * Caller must pass the return value in @prev on subsequent
731 * invocations for reference counting, or use mem_cgroup_iter_break()
732 * to cancel a hierarchy walk before the round-trip is complete.
734 * Reclaimers can specify a zone and a priority level in @reclaim to
735 * divide up the memcgs in the hierarchy among all concurrent
736 * reclaimers operating on the same zone and priority.
738 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
739 struct mem_cgroup
*prev
,
740 struct mem_cgroup_reclaim_cookie
*reclaim
)
742 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
743 struct cgroup_subsys_state
*css
= NULL
;
744 struct mem_cgroup
*memcg
= NULL
;
745 struct mem_cgroup
*pos
= NULL
;
747 if (mem_cgroup_disabled())
751 root
= root_mem_cgroup
;
753 if (prev
&& !reclaim
)
756 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
765 struct mem_cgroup_per_node
*mz
;
767 mz
= mem_cgroup_nodeinfo(root
, reclaim
->pgdat
->node_id
);
768 iter
= &mz
->iter
[reclaim
->priority
];
770 if (prev
&& reclaim
->generation
!= iter
->generation
)
774 pos
= READ_ONCE(iter
->position
);
775 if (!pos
|| css_tryget(&pos
->css
))
778 * css reference reached zero, so iter->position will
779 * be cleared by ->css_released. However, we should not
780 * rely on this happening soon, because ->css_released
781 * is called from a work queue, and by busy-waiting we
782 * might block it. So we clear iter->position right
785 (void)cmpxchg(&iter
->position
, pos
, NULL
);
793 css
= css_next_descendant_pre(css
, &root
->css
);
796 * Reclaimers share the hierarchy walk, and a
797 * new one might jump in right at the end of
798 * the hierarchy - make sure they see at least
799 * one group and restart from the beginning.
807 * Verify the css and acquire a reference. The root
808 * is provided by the caller, so we know it's alive
809 * and kicking, and don't take an extra reference.
811 memcg
= mem_cgroup_from_css(css
);
813 if (css
== &root
->css
)
824 * The position could have already been updated by a competing
825 * thread, so check that the value hasn't changed since we read
826 * it to avoid reclaiming from the same cgroup twice.
828 (void)cmpxchg(&iter
->position
, pos
, memcg
);
836 reclaim
->generation
= iter
->generation
;
842 if (prev
&& prev
!= root
)
849 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
850 * @root: hierarchy root
851 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
853 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
854 struct mem_cgroup
*prev
)
857 root
= root_mem_cgroup
;
858 if (prev
&& prev
!= root
)
862 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
864 struct mem_cgroup
*memcg
= dead_memcg
;
865 struct mem_cgroup_reclaim_iter
*iter
;
866 struct mem_cgroup_per_node
*mz
;
870 while ((memcg
= parent_mem_cgroup(memcg
))) {
872 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
873 for (i
= 0; i
<= DEF_PRIORITY
; i
++) {
875 cmpxchg(&iter
->position
,
883 * Iteration constructs for visiting all cgroups (under a tree). If
884 * loops are exited prematurely (break), mem_cgroup_iter_break() must
885 * be used for reference counting.
887 #define for_each_mem_cgroup_tree(iter, root) \
888 for (iter = mem_cgroup_iter(root, NULL, NULL); \
890 iter = mem_cgroup_iter(root, iter, NULL))
892 #define for_each_mem_cgroup(iter) \
893 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
895 iter = mem_cgroup_iter(NULL, iter, NULL))
898 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
899 * @memcg: hierarchy root
900 * @fn: function to call for each task
901 * @arg: argument passed to @fn
903 * This function iterates over tasks attached to @memcg or to any of its
904 * descendants and calls @fn for each task. If @fn returns a non-zero
905 * value, the function breaks the iteration loop and returns the value.
906 * Otherwise, it will iterate over all tasks and return 0.
908 * This function must not be called for the root memory cgroup.
910 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
911 int (*fn
)(struct task_struct
*, void *), void *arg
)
913 struct mem_cgroup
*iter
;
916 BUG_ON(memcg
== root_mem_cgroup
);
918 for_each_mem_cgroup_tree(iter
, memcg
) {
919 struct css_task_iter it
;
920 struct task_struct
*task
;
922 css_task_iter_start(&iter
->css
, 0, &it
);
923 while (!ret
&& (task
= css_task_iter_next(&it
)))
925 css_task_iter_end(&it
);
927 mem_cgroup_iter_break(memcg
, iter
);
935 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
937 * @zone: zone of the page
939 * This function is only safe when following the LRU page isolation
940 * and putback protocol: the LRU lock must be held, and the page must
941 * either be PageLRU() or the caller must have isolated/allocated it.
943 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct pglist_data
*pgdat
)
945 struct mem_cgroup_per_node
*mz
;
946 struct mem_cgroup
*memcg
;
947 struct lruvec
*lruvec
;
949 if (mem_cgroup_disabled()) {
950 lruvec
= &pgdat
->lruvec
;
954 memcg
= page
->mem_cgroup
;
956 * Swapcache readahead pages are added to the LRU - and
957 * possibly migrated - before they are charged.
960 memcg
= root_mem_cgroup
;
962 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
963 lruvec
= &mz
->lruvec
;
966 * Since a node can be onlined after the mem_cgroup was created,
967 * we have to be prepared to initialize lruvec->zone here;
968 * and if offlined then reonlined, we need to reinitialize it.
970 if (unlikely(lruvec
->pgdat
!= pgdat
))
971 lruvec
->pgdat
= pgdat
;
976 * mem_cgroup_update_lru_size - account for adding or removing an lru page
977 * @lruvec: mem_cgroup per zone lru vector
978 * @lru: index of lru list the page is sitting on
979 * @zid: zone id of the accounted pages
980 * @nr_pages: positive when adding or negative when removing
982 * This function must be called under lru_lock, just before a page is added
983 * to or just after a page is removed from an lru list (that ordering being
984 * so as to allow it to check that lru_size 0 is consistent with list_empty).
986 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
987 int zid
, int nr_pages
)
989 struct mem_cgroup_per_node
*mz
;
990 unsigned long *lru_size
;
993 if (mem_cgroup_disabled())
996 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
997 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1000 *lru_size
+= nr_pages
;
1003 if (WARN_ONCE(size
< 0,
1004 "%s(%p, %d, %d): lru_size %ld\n",
1005 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1011 *lru_size
+= nr_pages
;
1014 bool task_in_mem_cgroup(struct task_struct
*task
, struct mem_cgroup
*memcg
)
1016 struct mem_cgroup
*task_memcg
;
1017 struct task_struct
*p
;
1020 p
= find_lock_task_mm(task
);
1022 task_memcg
= get_mem_cgroup_from_mm(p
->mm
);
1026 * All threads may have already detached their mm's, but the oom
1027 * killer still needs to detect if they have already been oom
1028 * killed to prevent needlessly killing additional tasks.
1031 task_memcg
= mem_cgroup_from_task(task
);
1032 css_get(&task_memcg
->css
);
1035 ret
= mem_cgroup_is_descendant(task_memcg
, memcg
);
1036 css_put(&task_memcg
->css
);
1041 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1042 * @memcg: the memory cgroup
1044 * Returns the maximum amount of memory @mem can be charged with, in
1047 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1049 unsigned long margin
= 0;
1050 unsigned long count
;
1051 unsigned long limit
;
1053 count
= page_counter_read(&memcg
->memory
);
1054 limit
= READ_ONCE(memcg
->memory
.limit
);
1056 margin
= limit
- count
;
1058 if (do_memsw_account()) {
1059 count
= page_counter_read(&memcg
->memsw
);
1060 limit
= READ_ONCE(memcg
->memsw
.limit
);
1062 margin
= min(margin
, limit
- count
);
1071 * A routine for checking "mem" is under move_account() or not.
1073 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1074 * moving cgroups. This is for waiting at high-memory pressure
1077 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1079 struct mem_cgroup
*from
;
1080 struct mem_cgroup
*to
;
1083 * Unlike task_move routines, we access mc.to, mc.from not under
1084 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1086 spin_lock(&mc
.lock
);
1092 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1093 mem_cgroup_is_descendant(to
, memcg
);
1095 spin_unlock(&mc
.lock
);
1099 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1101 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1102 if (mem_cgroup_under_move(memcg
)) {
1104 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1105 /* moving charge context might have finished. */
1108 finish_wait(&mc
.waitq
, &wait
);
1115 unsigned int memcg1_stats
[] = {
1126 static const char *const memcg1_stat_names
[] = {
1137 #define K(x) ((x) << (PAGE_SHIFT-10))
1139 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1140 * @memcg: The memory cgroup that went over limit
1141 * @p: Task that is going to be killed
1143 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1146 void mem_cgroup_print_oom_info(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1148 struct mem_cgroup
*iter
;
1154 pr_info("Task in ");
1155 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1156 pr_cont(" killed as a result of limit of ");
1158 pr_info("Memory limit reached of cgroup ");
1161 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1166 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1167 K((u64
)page_counter_read(&memcg
->memory
)),
1168 K((u64
)memcg
->memory
.limit
), memcg
->memory
.failcnt
);
1169 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1170 K((u64
)page_counter_read(&memcg
->memsw
)),
1171 K((u64
)memcg
->memsw
.limit
), memcg
->memsw
.failcnt
);
1172 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1173 K((u64
)page_counter_read(&memcg
->kmem
)),
1174 K((u64
)memcg
->kmem
.limit
), memcg
->kmem
.failcnt
);
1176 for_each_mem_cgroup_tree(iter
, memcg
) {
1177 pr_info("Memory cgroup stats for ");
1178 pr_cont_cgroup_path(iter
->css
.cgroup
);
1181 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
1182 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_swap_account
)
1184 pr_cont(" %s:%luKB", memcg1_stat_names
[i
],
1185 K(memcg_page_state(iter
, memcg1_stats
[i
])));
1188 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1189 pr_cont(" %s:%luKB", mem_cgroup_lru_names
[i
],
1190 K(mem_cgroup_nr_lru_pages(iter
, BIT(i
))));
1197 * This function returns the number of memcg under hierarchy tree. Returns
1198 * 1(self count) if no children.
1200 static int mem_cgroup_count_children(struct mem_cgroup
*memcg
)
1203 struct mem_cgroup
*iter
;
1205 for_each_mem_cgroup_tree(iter
, memcg
)
1211 * Return the memory (and swap, if configured) limit for a memcg.
1213 unsigned long mem_cgroup_get_limit(struct mem_cgroup
*memcg
)
1215 unsigned long limit
;
1217 limit
= memcg
->memory
.limit
;
1218 if (mem_cgroup_swappiness(memcg
)) {
1219 unsigned long memsw_limit
;
1220 unsigned long swap_limit
;
1222 memsw_limit
= memcg
->memsw
.limit
;
1223 swap_limit
= memcg
->swap
.limit
;
1224 swap_limit
= min(swap_limit
, (unsigned long)total_swap_pages
);
1225 limit
= min(limit
+ swap_limit
, memsw_limit
);
1230 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1233 struct oom_control oc
= {
1237 .gfp_mask
= gfp_mask
,
1242 mutex_lock(&oom_lock
);
1243 ret
= out_of_memory(&oc
);
1244 mutex_unlock(&oom_lock
);
1248 #if MAX_NUMNODES > 1
1251 * test_mem_cgroup_node_reclaimable
1252 * @memcg: the target memcg
1253 * @nid: the node ID to be checked.
1254 * @noswap : specify true here if the user wants flle only information.
1256 * This function returns whether the specified memcg contains any
1257 * reclaimable pages on a node. Returns true if there are any reclaimable
1258 * pages in the node.
1260 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1261 int nid
, bool noswap
)
1263 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_FILE
))
1265 if (noswap
|| !total_swap_pages
)
1267 if (mem_cgroup_node_nr_lru_pages(memcg
, nid
, LRU_ALL_ANON
))
1274 * Always updating the nodemask is not very good - even if we have an empty
1275 * list or the wrong list here, we can start from some node and traverse all
1276 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1279 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1283 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1284 * pagein/pageout changes since the last update.
1286 if (!atomic_read(&memcg
->numainfo_events
))
1288 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1291 /* make a nodemask where this memcg uses memory from */
1292 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1294 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1296 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1297 node_clear(nid
, memcg
->scan_nodes
);
1300 atomic_set(&memcg
->numainfo_events
, 0);
1301 atomic_set(&memcg
->numainfo_updating
, 0);
1305 * Selecting a node where we start reclaim from. Because what we need is just
1306 * reducing usage counter, start from anywhere is O,K. Considering
1307 * memory reclaim from current node, there are pros. and cons.
1309 * Freeing memory from current node means freeing memory from a node which
1310 * we'll use or we've used. So, it may make LRU bad. And if several threads
1311 * hit limits, it will see a contention on a node. But freeing from remote
1312 * node means more costs for memory reclaim because of memory latency.
1314 * Now, we use round-robin. Better algorithm is welcomed.
1316 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1320 mem_cgroup_may_update_nodemask(memcg
);
1321 node
= memcg
->last_scanned_node
;
1323 node
= next_node_in(node
, memcg
->scan_nodes
);
1325 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1326 * last time it really checked all the LRUs due to rate limiting.
1327 * Fallback to the current node in that case for simplicity.
1329 if (unlikely(node
== MAX_NUMNODES
))
1330 node
= numa_node_id();
1332 memcg
->last_scanned_node
= node
;
1336 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1342 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1345 unsigned long *total_scanned
)
1347 struct mem_cgroup
*victim
= NULL
;
1350 unsigned long excess
;
1351 unsigned long nr_scanned
;
1352 struct mem_cgroup_reclaim_cookie reclaim
= {
1357 excess
= soft_limit_excess(root_memcg
);
1360 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1365 * If we have not been able to reclaim
1366 * anything, it might because there are
1367 * no reclaimable pages under this hierarchy
1372 * We want to do more targeted reclaim.
1373 * excess >> 2 is not to excessive so as to
1374 * reclaim too much, nor too less that we keep
1375 * coming back to reclaim from this cgroup
1377 if (total
>= (excess
>> 2) ||
1378 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1383 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1384 pgdat
, &nr_scanned
);
1385 *total_scanned
+= nr_scanned
;
1386 if (!soft_limit_excess(root_memcg
))
1389 mem_cgroup_iter_break(root_memcg
, victim
);
1393 #ifdef CONFIG_LOCKDEP
1394 static struct lockdep_map memcg_oom_lock_dep_map
= {
1395 .name
= "memcg_oom_lock",
1399 static DEFINE_SPINLOCK(memcg_oom_lock
);
1402 * Check OOM-Killer is already running under our hierarchy.
1403 * If someone is running, return false.
1405 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1407 struct mem_cgroup
*iter
, *failed
= NULL
;
1409 spin_lock(&memcg_oom_lock
);
1411 for_each_mem_cgroup_tree(iter
, memcg
) {
1412 if (iter
->oom_lock
) {
1414 * this subtree of our hierarchy is already locked
1415 * so we cannot give a lock.
1418 mem_cgroup_iter_break(memcg
, iter
);
1421 iter
->oom_lock
= true;
1426 * OK, we failed to lock the whole subtree so we have
1427 * to clean up what we set up to the failing subtree
1429 for_each_mem_cgroup_tree(iter
, memcg
) {
1430 if (iter
== failed
) {
1431 mem_cgroup_iter_break(memcg
, iter
);
1434 iter
->oom_lock
= false;
1437 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1439 spin_unlock(&memcg_oom_lock
);
1444 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1446 struct mem_cgroup
*iter
;
1448 spin_lock(&memcg_oom_lock
);
1449 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
1450 for_each_mem_cgroup_tree(iter
, memcg
)
1451 iter
->oom_lock
= false;
1452 spin_unlock(&memcg_oom_lock
);
1455 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1457 struct mem_cgroup
*iter
;
1459 spin_lock(&memcg_oom_lock
);
1460 for_each_mem_cgroup_tree(iter
, memcg
)
1462 spin_unlock(&memcg_oom_lock
);
1465 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1467 struct mem_cgroup
*iter
;
1470 * When a new child is created while the hierarchy is under oom,
1471 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1473 spin_lock(&memcg_oom_lock
);
1474 for_each_mem_cgroup_tree(iter
, memcg
)
1475 if (iter
->under_oom
> 0)
1477 spin_unlock(&memcg_oom_lock
);
1480 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1482 struct oom_wait_info
{
1483 struct mem_cgroup
*memcg
;
1484 wait_queue_entry_t wait
;
1487 static int memcg_oom_wake_function(wait_queue_entry_t
*wait
,
1488 unsigned mode
, int sync
, void *arg
)
1490 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1491 struct mem_cgroup
*oom_wait_memcg
;
1492 struct oom_wait_info
*oom_wait_info
;
1494 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1495 oom_wait_memcg
= oom_wait_info
->memcg
;
1497 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1498 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1500 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1503 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1506 * For the following lockless ->under_oom test, the only required
1507 * guarantee is that it must see the state asserted by an OOM when
1508 * this function is called as a result of userland actions
1509 * triggered by the notification of the OOM. This is trivially
1510 * achieved by invoking mem_cgroup_mark_under_oom() before
1511 * triggering notification.
1513 if (memcg
&& memcg
->under_oom
)
1514 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1517 static void mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1519 if (!current
->memcg_may_oom
)
1522 * We are in the middle of the charge context here, so we
1523 * don't want to block when potentially sitting on a callstack
1524 * that holds all kinds of filesystem and mm locks.
1526 * Also, the caller may handle a failed allocation gracefully
1527 * (like optional page cache readahead) and so an OOM killer
1528 * invocation might not even be necessary.
1530 * That's why we don't do anything here except remember the
1531 * OOM context and then deal with it at the end of the page
1532 * fault when the stack is unwound, the locks are released,
1533 * and when we know whether the fault was overall successful.
1535 css_get(&memcg
->css
);
1536 current
->memcg_in_oom
= memcg
;
1537 current
->memcg_oom_gfp_mask
= mask
;
1538 current
->memcg_oom_order
= order
;
1542 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1543 * @handle: actually kill/wait or just clean up the OOM state
1545 * This has to be called at the end of a page fault if the memcg OOM
1546 * handler was enabled.
1548 * Memcg supports userspace OOM handling where failed allocations must
1549 * sleep on a waitqueue until the userspace task resolves the
1550 * situation. Sleeping directly in the charge context with all kinds
1551 * of locks held is not a good idea, instead we remember an OOM state
1552 * in the task and mem_cgroup_oom_synchronize() has to be called at
1553 * the end of the page fault to complete the OOM handling.
1555 * Returns %true if an ongoing memcg OOM situation was detected and
1556 * completed, %false otherwise.
1558 bool mem_cgroup_oom_synchronize(bool handle
)
1560 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1561 struct oom_wait_info owait
;
1564 /* OOM is global, do not handle */
1571 owait
.memcg
= memcg
;
1572 owait
.wait
.flags
= 0;
1573 owait
.wait
.func
= memcg_oom_wake_function
;
1574 owait
.wait
.private = current
;
1575 INIT_LIST_HEAD(&owait
.wait
.entry
);
1577 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1578 mem_cgroup_mark_under_oom(memcg
);
1580 locked
= mem_cgroup_oom_trylock(memcg
);
1583 mem_cgroup_oom_notify(memcg
);
1585 if (locked
&& !memcg
->oom_kill_disable
) {
1586 mem_cgroup_unmark_under_oom(memcg
);
1587 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1588 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1589 current
->memcg_oom_order
);
1592 mem_cgroup_unmark_under_oom(memcg
);
1593 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1597 mem_cgroup_oom_unlock(memcg
);
1599 * There is no guarantee that an OOM-lock contender
1600 * sees the wakeups triggered by the OOM kill
1601 * uncharges. Wake any sleepers explicitely.
1603 memcg_oom_recover(memcg
);
1606 current
->memcg_in_oom
= NULL
;
1607 css_put(&memcg
->css
);
1612 * lock_page_memcg - lock a page->mem_cgroup binding
1615 * This function protects unlocked LRU pages from being moved to
1618 * It ensures lifetime of the returned memcg. Caller is responsible
1619 * for the lifetime of the page; __unlock_page_memcg() is available
1620 * when @page might get freed inside the locked section.
1622 struct mem_cgroup
*lock_page_memcg(struct page
*page
)
1624 struct mem_cgroup
*memcg
;
1625 unsigned long flags
;
1628 * The RCU lock is held throughout the transaction. The fast
1629 * path can get away without acquiring the memcg->move_lock
1630 * because page moving starts with an RCU grace period.
1632 * The RCU lock also protects the memcg from being freed when
1633 * the page state that is going to change is the only thing
1634 * preventing the page itself from being freed. E.g. writeback
1635 * doesn't hold a page reference and relies on PG_writeback to
1636 * keep off truncation, migration and so forth.
1640 if (mem_cgroup_disabled())
1643 memcg
= page
->mem_cgroup
;
1644 if (unlikely(!memcg
))
1647 if (atomic_read(&memcg
->moving_account
) <= 0)
1650 spin_lock_irqsave(&memcg
->move_lock
, flags
);
1651 if (memcg
!= page
->mem_cgroup
) {
1652 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1657 * When charge migration first begins, we can have locked and
1658 * unlocked page stat updates happening concurrently. Track
1659 * the task who has the lock for unlock_page_memcg().
1661 memcg
->move_lock_task
= current
;
1662 memcg
->move_lock_flags
= flags
;
1666 EXPORT_SYMBOL(lock_page_memcg
);
1669 * __unlock_page_memcg - unlock and unpin a memcg
1672 * Unlock and unpin a memcg returned by lock_page_memcg().
1674 void __unlock_page_memcg(struct mem_cgroup
*memcg
)
1676 if (memcg
&& memcg
->move_lock_task
== current
) {
1677 unsigned long flags
= memcg
->move_lock_flags
;
1679 memcg
->move_lock_task
= NULL
;
1680 memcg
->move_lock_flags
= 0;
1682 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1689 * unlock_page_memcg - unlock a page->mem_cgroup binding
1692 void unlock_page_memcg(struct page
*page
)
1694 __unlock_page_memcg(page
->mem_cgroup
);
1696 EXPORT_SYMBOL(unlock_page_memcg
);
1699 * size of first charge trial. "32" comes from vmscan.c's magic value.
1700 * TODO: maybe necessary to use big numbers in big irons.
1702 #define CHARGE_BATCH 32U
1703 struct memcg_stock_pcp
{
1704 struct mem_cgroup
*cached
; /* this never be root cgroup */
1705 unsigned int nr_pages
;
1706 struct work_struct work
;
1707 unsigned long flags
;
1708 #define FLUSHING_CACHED_CHARGE 0
1710 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
1711 static DEFINE_MUTEX(percpu_charge_mutex
);
1714 * consume_stock: Try to consume stocked charge on this cpu.
1715 * @memcg: memcg to consume from.
1716 * @nr_pages: how many pages to charge.
1718 * The charges will only happen if @memcg matches the current cpu's memcg
1719 * stock, and at least @nr_pages are available in that stock. Failure to
1720 * service an allocation will refill the stock.
1722 * returns true if successful, false otherwise.
1724 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1726 struct memcg_stock_pcp
*stock
;
1727 unsigned long flags
;
1730 if (nr_pages
> CHARGE_BATCH
)
1733 local_irq_save(flags
);
1735 stock
= this_cpu_ptr(&memcg_stock
);
1736 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
1737 stock
->nr_pages
-= nr_pages
;
1741 local_irq_restore(flags
);
1747 * Returns stocks cached in percpu and reset cached information.
1749 static void drain_stock(struct memcg_stock_pcp
*stock
)
1751 struct mem_cgroup
*old
= stock
->cached
;
1753 if (stock
->nr_pages
) {
1754 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
1755 if (do_memsw_account())
1756 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
1757 css_put_many(&old
->css
, stock
->nr_pages
);
1758 stock
->nr_pages
= 0;
1760 stock
->cached
= NULL
;
1763 static void drain_local_stock(struct work_struct
*dummy
)
1765 struct memcg_stock_pcp
*stock
;
1766 unsigned long flags
;
1768 local_irq_save(flags
);
1770 stock
= this_cpu_ptr(&memcg_stock
);
1772 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
1774 local_irq_restore(flags
);
1778 * Cache charges(val) to local per_cpu area.
1779 * This will be consumed by consume_stock() function, later.
1781 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
1783 struct memcg_stock_pcp
*stock
;
1784 unsigned long flags
;
1786 local_irq_save(flags
);
1788 stock
= this_cpu_ptr(&memcg_stock
);
1789 if (stock
->cached
!= memcg
) { /* reset if necessary */
1791 stock
->cached
= memcg
;
1793 stock
->nr_pages
+= nr_pages
;
1795 local_irq_restore(flags
);
1799 * Drains all per-CPU charge caches for given root_memcg resp. subtree
1800 * of the hierarchy under it.
1802 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
1806 /* If someone's already draining, avoid adding running more workers. */
1807 if (!mutex_trylock(&percpu_charge_mutex
))
1809 /* Notify other cpus that system-wide "drain" is running */
1812 for_each_online_cpu(cpu
) {
1813 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
1814 struct mem_cgroup
*memcg
;
1816 memcg
= stock
->cached
;
1817 if (!memcg
|| !stock
->nr_pages
)
1819 if (!mem_cgroup_is_descendant(memcg
, root_memcg
))
1821 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
1823 drain_local_stock(&stock
->work
);
1825 schedule_work_on(cpu
, &stock
->work
);
1830 mutex_unlock(&percpu_charge_mutex
);
1833 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
1835 struct memcg_stock_pcp
*stock
;
1837 stock
= &per_cpu(memcg_stock
, cpu
);
1842 static void reclaim_high(struct mem_cgroup
*memcg
,
1843 unsigned int nr_pages
,
1847 if (page_counter_read(&memcg
->memory
) <= memcg
->high
)
1849 mem_cgroup_event(memcg
, MEMCG_HIGH
);
1850 try_to_free_mem_cgroup_pages(memcg
, nr_pages
, gfp_mask
, true);
1851 } while ((memcg
= parent_mem_cgroup(memcg
)));
1854 static void high_work_func(struct work_struct
*work
)
1856 struct mem_cgroup
*memcg
;
1858 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
1859 reclaim_high(memcg
, CHARGE_BATCH
, GFP_KERNEL
);
1863 * Scheduled by try_charge() to be executed from the userland return path
1864 * and reclaims memory over the high limit.
1866 void mem_cgroup_handle_over_high(void)
1868 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
1869 struct mem_cgroup
*memcg
;
1871 if (likely(!nr_pages
))
1874 memcg
= get_mem_cgroup_from_mm(current
->mm
);
1875 reclaim_high(memcg
, nr_pages
, GFP_KERNEL
);
1876 css_put(&memcg
->css
);
1877 current
->memcg_nr_pages_over_high
= 0;
1880 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1881 unsigned int nr_pages
)
1883 unsigned int batch
= max(CHARGE_BATCH
, nr_pages
);
1884 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
1885 struct mem_cgroup
*mem_over_limit
;
1886 struct page_counter
*counter
;
1887 unsigned long nr_reclaimed
;
1888 bool may_swap
= true;
1889 bool drained
= false;
1891 if (mem_cgroup_is_root(memcg
))
1894 if (consume_stock(memcg
, nr_pages
))
1897 if (!do_memsw_account() ||
1898 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
1899 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
1901 if (do_memsw_account())
1902 page_counter_uncharge(&memcg
->memsw
, batch
);
1903 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
1905 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
1909 if (batch
> nr_pages
) {
1915 * Unlike in global OOM situations, memcg is not in a physical
1916 * memory shortage. Allow dying and OOM-killed tasks to
1917 * bypass the last charges so that they can exit quickly and
1918 * free their memory.
1920 if (unlikely(tsk_is_oom_victim(current
) ||
1921 fatal_signal_pending(current
) ||
1922 current
->flags
& PF_EXITING
))
1926 * Prevent unbounded recursion when reclaim operations need to
1927 * allocate memory. This might exceed the limits temporarily,
1928 * but we prefer facilitating memory reclaim and getting back
1929 * under the limit over triggering OOM kills in these cases.
1931 if (unlikely(current
->flags
& PF_MEMALLOC
))
1934 if (unlikely(task_in_memcg_oom(current
)))
1937 if (!gfpflags_allow_blocking(gfp_mask
))
1940 mem_cgroup_event(mem_over_limit
, MEMCG_MAX
);
1942 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
1943 gfp_mask
, may_swap
);
1945 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
1949 drain_all_stock(mem_over_limit
);
1954 if (gfp_mask
& __GFP_NORETRY
)
1957 * Even though the limit is exceeded at this point, reclaim
1958 * may have been able to free some pages. Retry the charge
1959 * before killing the task.
1961 * Only for regular pages, though: huge pages are rather
1962 * unlikely to succeed so close to the limit, and we fall back
1963 * to regular pages anyway in case of failure.
1965 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
1968 * At task move, charge accounts can be doubly counted. So, it's
1969 * better to wait until the end of task_move if something is going on.
1971 if (mem_cgroup_wait_acct_move(mem_over_limit
))
1977 if (gfp_mask
& __GFP_NOFAIL
)
1980 if (fatal_signal_pending(current
))
1983 mem_cgroup_event(mem_over_limit
, MEMCG_OOM
);
1985 mem_cgroup_oom(mem_over_limit
, gfp_mask
,
1986 get_order(nr_pages
* PAGE_SIZE
));
1988 if (!(gfp_mask
& __GFP_NOFAIL
))
1992 * The allocation either can't fail or will lead to more memory
1993 * being freed very soon. Allow memory usage go over the limit
1994 * temporarily by force charging it.
1996 page_counter_charge(&memcg
->memory
, nr_pages
);
1997 if (do_memsw_account())
1998 page_counter_charge(&memcg
->memsw
, nr_pages
);
1999 css_get_many(&memcg
->css
, nr_pages
);
2004 css_get_many(&memcg
->css
, batch
);
2005 if (batch
> nr_pages
)
2006 refill_stock(memcg
, batch
- nr_pages
);
2009 * If the hierarchy is above the normal consumption range, schedule
2010 * reclaim on returning to userland. We can perform reclaim here
2011 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2012 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2013 * not recorded as it most likely matches current's and won't
2014 * change in the meantime. As high limit is checked again before
2015 * reclaim, the cost of mismatch is negligible.
2018 if (page_counter_read(&memcg
->memory
) > memcg
->high
) {
2019 /* Don't bother a random interrupted task */
2020 if (in_interrupt()) {
2021 schedule_work(&memcg
->high_work
);
2024 current
->memcg_nr_pages_over_high
+= batch
;
2025 set_notify_resume(current
);
2028 } while ((memcg
= parent_mem_cgroup(memcg
)));
2033 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2035 if (mem_cgroup_is_root(memcg
))
2038 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2039 if (do_memsw_account())
2040 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2042 css_put_many(&memcg
->css
, nr_pages
);
2045 static void lock_page_lru(struct page
*page
, int *isolated
)
2047 struct zone
*zone
= page_zone(page
);
2049 spin_lock_irq(zone_lru_lock(zone
));
2050 if (PageLRU(page
)) {
2051 struct lruvec
*lruvec
;
2053 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2055 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2061 static void unlock_page_lru(struct page
*page
, int isolated
)
2063 struct zone
*zone
= page_zone(page
);
2066 struct lruvec
*lruvec
;
2068 lruvec
= mem_cgroup_page_lruvec(page
, zone
->zone_pgdat
);
2069 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2071 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2073 spin_unlock_irq(zone_lru_lock(zone
));
2076 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2081 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2084 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2085 * may already be on some other mem_cgroup's LRU. Take care of it.
2088 lock_page_lru(page
, &isolated
);
2091 * Nobody should be changing or seriously looking at
2092 * page->mem_cgroup at this point:
2094 * - the page is uncharged
2096 * - the page is off-LRU
2098 * - an anonymous fault has exclusive page access, except for
2099 * a locked page table
2101 * - a page cache insertion, a swapin fault, or a migration
2102 * have the page locked
2104 page
->mem_cgroup
= memcg
;
2107 unlock_page_lru(page
, isolated
);
2111 static int memcg_alloc_cache_id(void)
2116 id
= ida_simple_get(&memcg_cache_ida
,
2117 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2121 if (id
< memcg_nr_cache_ids
)
2125 * There's no space for the new id in memcg_caches arrays,
2126 * so we have to grow them.
2128 down_write(&memcg_cache_ids_sem
);
2130 size
= 2 * (id
+ 1);
2131 if (size
< MEMCG_CACHES_MIN_SIZE
)
2132 size
= MEMCG_CACHES_MIN_SIZE
;
2133 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2134 size
= MEMCG_CACHES_MAX_SIZE
;
2136 err
= memcg_update_all_caches(size
);
2138 err
= memcg_update_all_list_lrus(size
);
2140 memcg_nr_cache_ids
= size
;
2142 up_write(&memcg_cache_ids_sem
);
2145 ida_simple_remove(&memcg_cache_ida
, id
);
2151 static void memcg_free_cache_id(int id
)
2153 ida_simple_remove(&memcg_cache_ida
, id
);
2156 struct memcg_kmem_cache_create_work
{
2157 struct mem_cgroup
*memcg
;
2158 struct kmem_cache
*cachep
;
2159 struct work_struct work
;
2162 static void memcg_kmem_cache_create_func(struct work_struct
*w
)
2164 struct memcg_kmem_cache_create_work
*cw
=
2165 container_of(w
, struct memcg_kmem_cache_create_work
, work
);
2166 struct mem_cgroup
*memcg
= cw
->memcg
;
2167 struct kmem_cache
*cachep
= cw
->cachep
;
2169 memcg_create_kmem_cache(memcg
, cachep
);
2171 css_put(&memcg
->css
);
2176 * Enqueue the creation of a per-memcg kmem_cache.
2178 static void __memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2179 struct kmem_cache
*cachep
)
2181 struct memcg_kmem_cache_create_work
*cw
;
2183 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
);
2187 css_get(&memcg
->css
);
2190 cw
->cachep
= cachep
;
2191 INIT_WORK(&cw
->work
, memcg_kmem_cache_create_func
);
2193 queue_work(memcg_kmem_cache_wq
, &cw
->work
);
2196 static void memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2197 struct kmem_cache
*cachep
)
2200 * We need to stop accounting when we kmalloc, because if the
2201 * corresponding kmalloc cache is not yet created, the first allocation
2202 * in __memcg_schedule_kmem_cache_create will recurse.
2204 * However, it is better to enclose the whole function. Depending on
2205 * the debugging options enabled, INIT_WORK(), for instance, can
2206 * trigger an allocation. This too, will make us recurse. Because at
2207 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2208 * the safest choice is to do it like this, wrapping the whole function.
2210 current
->memcg_kmem_skip_account
= 1;
2211 __memcg_schedule_kmem_cache_create(memcg
, cachep
);
2212 current
->memcg_kmem_skip_account
= 0;
2215 static inline bool memcg_kmem_bypass(void)
2217 if (in_interrupt() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
2223 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2224 * @cachep: the original global kmem cache
2226 * Return the kmem_cache we're supposed to use for a slab allocation.
2227 * We try to use the current memcg's version of the cache.
2229 * If the cache does not exist yet, if we are the first user of it, we
2230 * create it asynchronously in a workqueue and let the current allocation
2231 * go through with the original cache.
2233 * This function takes a reference to the cache it returns to assure it
2234 * won't get destroyed while we are working with it. Once the caller is
2235 * done with it, memcg_kmem_put_cache() must be called to release the
2238 struct kmem_cache
*memcg_kmem_get_cache(struct kmem_cache
*cachep
)
2240 struct mem_cgroup
*memcg
;
2241 struct kmem_cache
*memcg_cachep
;
2244 VM_BUG_ON(!is_root_cache(cachep
));
2246 if (memcg_kmem_bypass())
2249 if (current
->memcg_kmem_skip_account
)
2252 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2253 kmemcg_id
= READ_ONCE(memcg
->kmemcg_id
);
2257 memcg_cachep
= cache_from_memcg_idx(cachep
, kmemcg_id
);
2258 if (likely(memcg_cachep
))
2259 return memcg_cachep
;
2262 * If we are in a safe context (can wait, and not in interrupt
2263 * context), we could be be predictable and return right away.
2264 * This would guarantee that the allocation being performed
2265 * already belongs in the new cache.
2267 * However, there are some clashes that can arrive from locking.
2268 * For instance, because we acquire the slab_mutex while doing
2269 * memcg_create_kmem_cache, this means no further allocation
2270 * could happen with the slab_mutex held. So it's better to
2273 memcg_schedule_kmem_cache_create(memcg
, cachep
);
2275 css_put(&memcg
->css
);
2280 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2281 * @cachep: the cache returned by memcg_kmem_get_cache
2283 void memcg_kmem_put_cache(struct kmem_cache
*cachep
)
2285 if (!is_root_cache(cachep
))
2286 css_put(&cachep
->memcg_params
.memcg
->css
);
2290 * memcg_kmem_charge: charge a kmem page
2291 * @page: page to charge
2292 * @gfp: reclaim mode
2293 * @order: allocation order
2294 * @memcg: memory cgroup to charge
2296 * Returns 0 on success, an error code on failure.
2298 int memcg_kmem_charge_memcg(struct page
*page
, gfp_t gfp
, int order
,
2299 struct mem_cgroup
*memcg
)
2301 unsigned int nr_pages
= 1 << order
;
2302 struct page_counter
*counter
;
2305 ret
= try_charge(memcg
, gfp
, nr_pages
);
2309 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2310 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2311 cancel_charge(memcg
, nr_pages
);
2315 page
->mem_cgroup
= memcg
;
2321 * memcg_kmem_charge: charge a kmem page to the current memory cgroup
2322 * @page: page to charge
2323 * @gfp: reclaim mode
2324 * @order: allocation order
2326 * Returns 0 on success, an error code on failure.
2328 int memcg_kmem_charge(struct page
*page
, gfp_t gfp
, int order
)
2330 struct mem_cgroup
*memcg
;
2333 if (memcg_kmem_bypass())
2336 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2337 if (!mem_cgroup_is_root(memcg
)) {
2338 ret
= memcg_kmem_charge_memcg(page
, gfp
, order
, memcg
);
2340 __SetPageKmemcg(page
);
2342 css_put(&memcg
->css
);
2346 * memcg_kmem_uncharge: uncharge a kmem page
2347 * @page: page to uncharge
2348 * @order: allocation order
2350 void memcg_kmem_uncharge(struct page
*page
, int order
)
2352 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
2353 unsigned int nr_pages
= 1 << order
;
2358 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
2360 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2361 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2363 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2364 if (do_memsw_account())
2365 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2367 page
->mem_cgroup
= NULL
;
2369 /* slab pages do not have PageKmemcg flag set */
2370 if (PageKmemcg(page
))
2371 __ClearPageKmemcg(page
);
2373 css_put_many(&memcg
->css
, nr_pages
);
2375 #endif /* !CONFIG_SLOB */
2377 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2380 * Because tail pages are not marked as "used", set it. We're under
2381 * zone_lru_lock and migration entries setup in all page mappings.
2383 void mem_cgroup_split_huge_fixup(struct page
*head
)
2387 if (mem_cgroup_disabled())
2390 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
2391 head
[i
].mem_cgroup
= head
->mem_cgroup
;
2393 __this_cpu_sub(head
->mem_cgroup
->stat
->count
[MEMCG_RSS_HUGE
],
2396 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2398 #ifdef CONFIG_MEMCG_SWAP
2399 static void mem_cgroup_swap_statistics(struct mem_cgroup
*memcg
,
2402 this_cpu_add(memcg
->stat
->count
[MEMCG_SWAP
], nr_entries
);
2406 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2407 * @entry: swap entry to be moved
2408 * @from: mem_cgroup which the entry is moved from
2409 * @to: mem_cgroup which the entry is moved to
2411 * It succeeds only when the swap_cgroup's record for this entry is the same
2412 * as the mem_cgroup's id of @from.
2414 * Returns 0 on success, -EINVAL on failure.
2416 * The caller must have charged to @to, IOW, called page_counter_charge() about
2417 * both res and memsw, and called css_get().
2419 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
2420 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2422 unsigned short old_id
, new_id
;
2424 old_id
= mem_cgroup_id(from
);
2425 new_id
= mem_cgroup_id(to
);
2427 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
2428 mem_cgroup_swap_statistics(from
, -1);
2429 mem_cgroup_swap_statistics(to
, 1);
2435 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
2436 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
2442 static DEFINE_MUTEX(memcg_limit_mutex
);
2444 static int mem_cgroup_resize_limit(struct mem_cgroup
*memcg
,
2445 unsigned long limit
)
2447 unsigned long curusage
;
2448 unsigned long oldusage
;
2449 bool enlarge
= false;
2454 * For keeping hierarchical_reclaim simple, how long we should retry
2455 * is depends on callers. We set our retry-count to be function
2456 * of # of children which we should visit in this loop.
2458 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2459 mem_cgroup_count_children(memcg
);
2461 oldusage
= page_counter_read(&memcg
->memory
);
2464 if (signal_pending(current
)) {
2469 mutex_lock(&memcg_limit_mutex
);
2470 if (limit
> memcg
->memsw
.limit
) {
2471 mutex_unlock(&memcg_limit_mutex
);
2475 if (limit
> memcg
->memory
.limit
)
2477 ret
= page_counter_limit(&memcg
->memory
, limit
);
2478 mutex_unlock(&memcg_limit_mutex
);
2483 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, true);
2485 curusage
= page_counter_read(&memcg
->memory
);
2486 /* Usage is reduced ? */
2487 if (curusage
>= oldusage
)
2490 oldusage
= curusage
;
2491 } while (retry_count
);
2493 if (!ret
&& enlarge
)
2494 memcg_oom_recover(memcg
);
2499 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup
*memcg
,
2500 unsigned long limit
)
2502 unsigned long curusage
;
2503 unsigned long oldusage
;
2504 bool enlarge
= false;
2508 /* see mem_cgroup_resize_res_limit */
2509 retry_count
= MEM_CGROUP_RECLAIM_RETRIES
*
2510 mem_cgroup_count_children(memcg
);
2512 oldusage
= page_counter_read(&memcg
->memsw
);
2515 if (signal_pending(current
)) {
2520 mutex_lock(&memcg_limit_mutex
);
2521 if (limit
< memcg
->memory
.limit
) {
2522 mutex_unlock(&memcg_limit_mutex
);
2526 if (limit
> memcg
->memsw
.limit
)
2528 ret
= page_counter_limit(&memcg
->memsw
, limit
);
2529 mutex_unlock(&memcg_limit_mutex
);
2534 try_to_free_mem_cgroup_pages(memcg
, 1, GFP_KERNEL
, false);
2536 curusage
= page_counter_read(&memcg
->memsw
);
2537 /* Usage is reduced ? */
2538 if (curusage
>= oldusage
)
2541 oldusage
= curusage
;
2542 } while (retry_count
);
2544 if (!ret
&& enlarge
)
2545 memcg_oom_recover(memcg
);
2550 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
2552 unsigned long *total_scanned
)
2554 unsigned long nr_reclaimed
= 0;
2555 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
2556 unsigned long reclaimed
;
2558 struct mem_cgroup_tree_per_node
*mctz
;
2559 unsigned long excess
;
2560 unsigned long nr_scanned
;
2565 mctz
= soft_limit_tree_node(pgdat
->node_id
);
2568 * Do not even bother to check the largest node if the root
2569 * is empty. Do it lockless to prevent lock bouncing. Races
2570 * are acceptable as soft limit is best effort anyway.
2572 if (!mctz
|| RB_EMPTY_ROOT(&mctz
->rb_root
))
2576 * This loop can run a while, specially if mem_cgroup's continuously
2577 * keep exceeding their soft limit and putting the system under
2584 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
2589 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
2590 gfp_mask
, &nr_scanned
);
2591 nr_reclaimed
+= reclaimed
;
2592 *total_scanned
+= nr_scanned
;
2593 spin_lock_irq(&mctz
->lock
);
2594 __mem_cgroup_remove_exceeded(mz
, mctz
);
2597 * If we failed to reclaim anything from this memory cgroup
2598 * it is time to move on to the next cgroup
2602 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
2604 excess
= soft_limit_excess(mz
->memcg
);
2606 * One school of thought says that we should not add
2607 * back the node to the tree if reclaim returns 0.
2608 * But our reclaim could return 0, simply because due
2609 * to priority we are exposing a smaller subset of
2610 * memory to reclaim from. Consider this as a longer
2613 /* If excess == 0, no tree ops */
2614 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
2615 spin_unlock_irq(&mctz
->lock
);
2616 css_put(&mz
->memcg
->css
);
2619 * Could not reclaim anything and there are no more
2620 * mem cgroups to try or we seem to be looping without
2621 * reclaiming anything.
2623 if (!nr_reclaimed
&&
2625 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
2627 } while (!nr_reclaimed
);
2629 css_put(&next_mz
->memcg
->css
);
2630 return nr_reclaimed
;
2634 * Test whether @memcg has children, dead or alive. Note that this
2635 * function doesn't care whether @memcg has use_hierarchy enabled and
2636 * returns %true if there are child csses according to the cgroup
2637 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
2639 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
2644 ret
= css_next_child(NULL
, &memcg
->css
);
2650 * Reclaims as many pages from the given memcg as possible.
2652 * Caller is responsible for holding css reference for memcg.
2654 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
2656 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2658 /* we call try-to-free pages for make this cgroup empty */
2659 lru_add_drain_all();
2660 /* try to free all pages in this cgroup */
2661 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
2664 if (signal_pending(current
))
2667 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
2671 /* maybe some writeback is necessary */
2672 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
2680 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
2681 char *buf
, size_t nbytes
,
2684 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2686 if (mem_cgroup_is_root(memcg
))
2688 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
2691 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
2694 return mem_cgroup_from_css(css
)->use_hierarchy
;
2697 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
2698 struct cftype
*cft
, u64 val
)
2701 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2702 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
2704 if (memcg
->use_hierarchy
== val
)
2708 * If parent's use_hierarchy is set, we can't make any modifications
2709 * in the child subtrees. If it is unset, then the change can
2710 * occur, provided the current cgroup has no children.
2712 * For the root cgroup, parent_mem is NULL, we allow value to be
2713 * set if there are no children.
2715 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
2716 (val
== 1 || val
== 0)) {
2717 if (!memcg_has_children(memcg
))
2718 memcg
->use_hierarchy
= val
;
2727 static void tree_stat(struct mem_cgroup
*memcg
, unsigned long *stat
)
2729 struct mem_cgroup
*iter
;
2732 memset(stat
, 0, sizeof(*stat
) * MEMCG_NR_STAT
);
2734 for_each_mem_cgroup_tree(iter
, memcg
) {
2735 for (i
= 0; i
< MEMCG_NR_STAT
; i
++)
2736 stat
[i
] += memcg_page_state(iter
, i
);
2740 static void tree_events(struct mem_cgroup
*memcg
, unsigned long *events
)
2742 struct mem_cgroup
*iter
;
2745 memset(events
, 0, sizeof(*events
) * MEMCG_NR_EVENTS
);
2747 for_each_mem_cgroup_tree(iter
, memcg
) {
2748 for (i
= 0; i
< MEMCG_NR_EVENTS
; i
++)
2749 events
[i
] += memcg_sum_events(iter
, i
);
2753 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
2755 unsigned long val
= 0;
2757 if (mem_cgroup_is_root(memcg
)) {
2758 struct mem_cgroup
*iter
;
2760 for_each_mem_cgroup_tree(iter
, memcg
) {
2761 val
+= memcg_page_state(iter
, MEMCG_CACHE
);
2762 val
+= memcg_page_state(iter
, MEMCG_RSS
);
2764 val
+= memcg_page_state(iter
, MEMCG_SWAP
);
2768 val
= page_counter_read(&memcg
->memory
);
2770 val
= page_counter_read(&memcg
->memsw
);
2783 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
2786 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
2787 struct page_counter
*counter
;
2789 switch (MEMFILE_TYPE(cft
->private)) {
2791 counter
= &memcg
->memory
;
2794 counter
= &memcg
->memsw
;
2797 counter
= &memcg
->kmem
;
2800 counter
= &memcg
->tcpmem
;
2806 switch (MEMFILE_ATTR(cft
->private)) {
2808 if (counter
== &memcg
->memory
)
2809 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
2810 if (counter
== &memcg
->memsw
)
2811 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
2812 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
2814 return (u64
)counter
->limit
* PAGE_SIZE
;
2816 return (u64
)counter
->watermark
* PAGE_SIZE
;
2818 return counter
->failcnt
;
2819 case RES_SOFT_LIMIT
:
2820 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
2827 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2831 if (cgroup_memory_nokmem
)
2834 BUG_ON(memcg
->kmemcg_id
>= 0);
2835 BUG_ON(memcg
->kmem_state
);
2837 memcg_id
= memcg_alloc_cache_id();
2841 static_branch_inc(&memcg_kmem_enabled_key
);
2843 * A memory cgroup is considered kmem-online as soon as it gets
2844 * kmemcg_id. Setting the id after enabling static branching will
2845 * guarantee no one starts accounting before all call sites are
2848 memcg
->kmemcg_id
= memcg_id
;
2849 memcg
->kmem_state
= KMEM_ONLINE
;
2850 INIT_LIST_HEAD(&memcg
->kmem_caches
);
2855 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2857 struct cgroup_subsys_state
*css
;
2858 struct mem_cgroup
*parent
, *child
;
2861 if (memcg
->kmem_state
!= KMEM_ONLINE
)
2864 * Clear the online state before clearing memcg_caches array
2865 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
2866 * guarantees that no cache will be created for this cgroup
2867 * after we are done (see memcg_create_kmem_cache()).
2869 memcg
->kmem_state
= KMEM_ALLOCATED
;
2871 memcg_deactivate_kmem_caches(memcg
);
2873 kmemcg_id
= memcg
->kmemcg_id
;
2874 BUG_ON(kmemcg_id
< 0);
2876 parent
= parent_mem_cgroup(memcg
);
2878 parent
= root_mem_cgroup
;
2881 * Change kmemcg_id of this cgroup and all its descendants to the
2882 * parent's id, and then move all entries from this cgroup's list_lrus
2883 * to ones of the parent. After we have finished, all list_lrus
2884 * corresponding to this cgroup are guaranteed to remain empty. The
2885 * ordering is imposed by list_lru_node->lock taken by
2886 * memcg_drain_all_list_lrus().
2888 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
2889 css_for_each_descendant_pre(css
, &memcg
->css
) {
2890 child
= mem_cgroup_from_css(css
);
2891 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
2892 child
->kmemcg_id
= parent
->kmemcg_id
;
2893 if (!memcg
->use_hierarchy
)
2898 memcg_drain_all_list_lrus(kmemcg_id
, parent
->kmemcg_id
);
2900 memcg_free_cache_id(kmemcg_id
);
2903 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2905 /* css_alloc() failed, offlining didn't happen */
2906 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
2907 memcg_offline_kmem(memcg
);
2909 if (memcg
->kmem_state
== KMEM_ALLOCATED
) {
2910 memcg_destroy_kmem_caches(memcg
);
2911 static_branch_dec(&memcg_kmem_enabled_key
);
2912 WARN_ON(page_counter_read(&memcg
->kmem
));
2916 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
2920 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
2923 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
2926 #endif /* !CONFIG_SLOB */
2928 static int memcg_update_kmem_limit(struct mem_cgroup
*memcg
,
2929 unsigned long limit
)
2933 mutex_lock(&memcg_limit_mutex
);
2934 ret
= page_counter_limit(&memcg
->kmem
, limit
);
2935 mutex_unlock(&memcg_limit_mutex
);
2939 static int memcg_update_tcp_limit(struct mem_cgroup
*memcg
, unsigned long limit
)
2943 mutex_lock(&memcg_limit_mutex
);
2945 ret
= page_counter_limit(&memcg
->tcpmem
, limit
);
2949 if (!memcg
->tcpmem_active
) {
2951 * The active flag needs to be written after the static_key
2952 * update. This is what guarantees that the socket activation
2953 * function is the last one to run. See mem_cgroup_sk_alloc()
2954 * for details, and note that we don't mark any socket as
2955 * belonging to this memcg until that flag is up.
2957 * We need to do this, because static_keys will span multiple
2958 * sites, but we can't control their order. If we mark a socket
2959 * as accounted, but the accounting functions are not patched in
2960 * yet, we'll lose accounting.
2962 * We never race with the readers in mem_cgroup_sk_alloc(),
2963 * because when this value change, the code to process it is not
2966 static_branch_inc(&memcg_sockets_enabled_key
);
2967 memcg
->tcpmem_active
= true;
2970 mutex_unlock(&memcg_limit_mutex
);
2975 * The user of this function is...
2978 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
2979 char *buf
, size_t nbytes
, loff_t off
)
2981 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
2982 unsigned long nr_pages
;
2985 buf
= strstrip(buf
);
2986 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
2990 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
2992 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
2996 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
2998 ret
= mem_cgroup_resize_limit(memcg
, nr_pages
);
3001 ret
= mem_cgroup_resize_memsw_limit(memcg
, nr_pages
);
3004 ret
= memcg_update_kmem_limit(memcg
, nr_pages
);
3007 ret
= memcg_update_tcp_limit(memcg
, nr_pages
);
3011 case RES_SOFT_LIMIT
:
3012 memcg
->soft_limit
= nr_pages
;
3016 return ret
?: nbytes
;
3019 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3020 size_t nbytes
, loff_t off
)
3022 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3023 struct page_counter
*counter
;
3025 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3027 counter
= &memcg
->memory
;
3030 counter
= &memcg
->memsw
;
3033 counter
= &memcg
->kmem
;
3036 counter
= &memcg
->tcpmem
;
3042 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3044 page_counter_reset_watermark(counter
);
3047 counter
->failcnt
= 0;
3056 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3059 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3063 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3064 struct cftype
*cft
, u64 val
)
3066 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3068 if (val
& ~MOVE_MASK
)
3072 * No kind of locking is needed in here, because ->can_attach() will
3073 * check this value once in the beginning of the process, and then carry
3074 * on with stale data. This means that changes to this value will only
3075 * affect task migrations starting after the change.
3077 memcg
->move_charge_at_immigrate
= val
;
3081 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3082 struct cftype
*cft
, u64 val
)
3089 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3093 unsigned int lru_mask
;
3096 static const struct numa_stat stats
[] = {
3097 { "total", LRU_ALL
},
3098 { "file", LRU_ALL_FILE
},
3099 { "anon", LRU_ALL_ANON
},
3100 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3102 const struct numa_stat
*stat
;
3105 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3107 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3108 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
3109 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
3110 for_each_node_state(nid
, N_MEMORY
) {
3111 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3113 seq_printf(m
, " N%d=%lu", nid
, nr
);
3118 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3119 struct mem_cgroup
*iter
;
3122 for_each_mem_cgroup_tree(iter
, memcg
)
3123 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
3124 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
3125 for_each_node_state(nid
, N_MEMORY
) {
3127 for_each_mem_cgroup_tree(iter
, memcg
)
3128 nr
+= mem_cgroup_node_nr_lru_pages(
3129 iter
, nid
, stat
->lru_mask
);
3130 seq_printf(m
, " N%d=%lu", nid
, nr
);
3137 #endif /* CONFIG_NUMA */
3139 /* Universal VM events cgroup1 shows, original sort order */
3140 unsigned int memcg1_events
[] = {
3147 static const char *const memcg1_event_names
[] = {
3154 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3156 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
3157 unsigned long memory
, memsw
;
3158 struct mem_cgroup
*mi
;
3161 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names
) != ARRAY_SIZE(memcg1_stats
));
3162 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
3164 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3165 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3167 seq_printf(m
, "%s %lu\n", memcg1_stat_names
[i
],
3168 memcg_page_state(memcg
, memcg1_stats
[i
]) *
3172 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3173 seq_printf(m
, "%s %lu\n", memcg1_event_names
[i
],
3174 memcg_sum_events(memcg
, memcg1_events
[i
]));
3176 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3177 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
3178 mem_cgroup_nr_lru_pages(memcg
, BIT(i
)) * PAGE_SIZE
);
3180 /* Hierarchical information */
3181 memory
= memsw
= PAGE_COUNTER_MAX
;
3182 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3183 memory
= min(memory
, mi
->memory
.limit
);
3184 memsw
= min(memsw
, mi
->memsw
.limit
);
3186 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3187 (u64
)memory
* PAGE_SIZE
);
3188 if (do_memsw_account())
3189 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3190 (u64
)memsw
* PAGE_SIZE
);
3192 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3193 unsigned long long val
= 0;
3195 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3197 for_each_mem_cgroup_tree(mi
, memcg
)
3198 val
+= memcg_page_state(mi
, memcg1_stats
[i
]) *
3200 seq_printf(m
, "total_%s %llu\n", memcg1_stat_names
[i
], val
);
3203 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++) {
3204 unsigned long long val
= 0;
3206 for_each_mem_cgroup_tree(mi
, memcg
)
3207 val
+= memcg_sum_events(mi
, memcg1_events
[i
]);
3208 seq_printf(m
, "total_%s %llu\n", memcg1_event_names
[i
], val
);
3211 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
3212 unsigned long long val
= 0;
3214 for_each_mem_cgroup_tree(mi
, memcg
)
3215 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
)) * PAGE_SIZE
;
3216 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
], val
);
3219 #ifdef CONFIG_DEBUG_VM
3222 struct mem_cgroup_per_node
*mz
;
3223 struct zone_reclaim_stat
*rstat
;
3224 unsigned long recent_rotated
[2] = {0, 0};
3225 unsigned long recent_scanned
[2] = {0, 0};
3227 for_each_online_pgdat(pgdat
) {
3228 mz
= mem_cgroup_nodeinfo(memcg
, pgdat
->node_id
);
3229 rstat
= &mz
->lruvec
.reclaim_stat
;
3231 recent_rotated
[0] += rstat
->recent_rotated
[0];
3232 recent_rotated
[1] += rstat
->recent_rotated
[1];
3233 recent_scanned
[0] += rstat
->recent_scanned
[0];
3234 recent_scanned
[1] += rstat
->recent_scanned
[1];
3236 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
3237 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
3238 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
3239 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
3246 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3249 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3251 return mem_cgroup_swappiness(memcg
);
3254 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3255 struct cftype
*cft
, u64 val
)
3257 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3263 memcg
->swappiness
= val
;
3265 vm_swappiness
= val
;
3270 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3272 struct mem_cgroup_threshold_ary
*t
;
3273 unsigned long usage
;
3278 t
= rcu_dereference(memcg
->thresholds
.primary
);
3280 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3285 usage
= mem_cgroup_usage(memcg
, swap
);
3288 * current_threshold points to threshold just below or equal to usage.
3289 * If it's not true, a threshold was crossed after last
3290 * call of __mem_cgroup_threshold().
3292 i
= t
->current_threshold
;
3295 * Iterate backward over array of thresholds starting from
3296 * current_threshold and check if a threshold is crossed.
3297 * If none of thresholds below usage is crossed, we read
3298 * only one element of the array here.
3300 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3301 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3303 /* i = current_threshold + 1 */
3307 * Iterate forward over array of thresholds starting from
3308 * current_threshold+1 and check if a threshold is crossed.
3309 * If none of thresholds above usage is crossed, we read
3310 * only one element of the array here.
3312 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
3313 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3315 /* Update current_threshold */
3316 t
->current_threshold
= i
- 1;
3321 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
3324 __mem_cgroup_threshold(memcg
, false);
3325 if (do_memsw_account())
3326 __mem_cgroup_threshold(memcg
, true);
3328 memcg
= parent_mem_cgroup(memcg
);
3332 static int compare_thresholds(const void *a
, const void *b
)
3334 const struct mem_cgroup_threshold
*_a
= a
;
3335 const struct mem_cgroup_threshold
*_b
= b
;
3337 if (_a
->threshold
> _b
->threshold
)
3340 if (_a
->threshold
< _b
->threshold
)
3346 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
3348 struct mem_cgroup_eventfd_list
*ev
;
3350 spin_lock(&memcg_oom_lock
);
3352 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
3353 eventfd_signal(ev
->eventfd
, 1);
3355 spin_unlock(&memcg_oom_lock
);
3359 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
3361 struct mem_cgroup
*iter
;
3363 for_each_mem_cgroup_tree(iter
, memcg
)
3364 mem_cgroup_oom_notify_cb(iter
);
3367 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3368 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
3370 struct mem_cgroup_thresholds
*thresholds
;
3371 struct mem_cgroup_threshold_ary
*new;
3372 unsigned long threshold
;
3373 unsigned long usage
;
3376 ret
= page_counter_memparse(args
, "-1", &threshold
);
3380 mutex_lock(&memcg
->thresholds_lock
);
3383 thresholds
= &memcg
->thresholds
;
3384 usage
= mem_cgroup_usage(memcg
, false);
3385 } else if (type
== _MEMSWAP
) {
3386 thresholds
= &memcg
->memsw_thresholds
;
3387 usage
= mem_cgroup_usage(memcg
, true);
3391 /* Check if a threshold crossed before adding a new one */
3392 if (thresholds
->primary
)
3393 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3395 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
3397 /* Allocate memory for new array of thresholds */
3398 new = kmalloc(sizeof(*new) + size
* sizeof(struct mem_cgroup_threshold
),
3406 /* Copy thresholds (if any) to new array */
3407 if (thresholds
->primary
) {
3408 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
3409 sizeof(struct mem_cgroup_threshold
));
3412 /* Add new threshold */
3413 new->entries
[size
- 1].eventfd
= eventfd
;
3414 new->entries
[size
- 1].threshold
= threshold
;
3416 /* Sort thresholds. Registering of new threshold isn't time-critical */
3417 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
3418 compare_thresholds
, NULL
);
3420 /* Find current threshold */
3421 new->current_threshold
= -1;
3422 for (i
= 0; i
< size
; i
++) {
3423 if (new->entries
[i
].threshold
<= usage
) {
3425 * new->current_threshold will not be used until
3426 * rcu_assign_pointer(), so it's safe to increment
3429 ++new->current_threshold
;
3434 /* Free old spare buffer and save old primary buffer as spare */
3435 kfree(thresholds
->spare
);
3436 thresholds
->spare
= thresholds
->primary
;
3438 rcu_assign_pointer(thresholds
->primary
, new);
3440 /* To be sure that nobody uses thresholds */
3444 mutex_unlock(&memcg
->thresholds_lock
);
3449 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3450 struct eventfd_ctx
*eventfd
, const char *args
)
3452 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
3455 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3456 struct eventfd_ctx
*eventfd
, const char *args
)
3458 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
3461 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3462 struct eventfd_ctx
*eventfd
, enum res_type type
)
3464 struct mem_cgroup_thresholds
*thresholds
;
3465 struct mem_cgroup_threshold_ary
*new;
3466 unsigned long usage
;
3469 mutex_lock(&memcg
->thresholds_lock
);
3472 thresholds
= &memcg
->thresholds
;
3473 usage
= mem_cgroup_usage(memcg
, false);
3474 } else if (type
== _MEMSWAP
) {
3475 thresholds
= &memcg
->memsw_thresholds
;
3476 usage
= mem_cgroup_usage(memcg
, true);
3480 if (!thresholds
->primary
)
3483 /* Check if a threshold crossed before removing */
3484 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
3486 /* Calculate new number of threshold */
3488 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
3489 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
3493 new = thresholds
->spare
;
3495 /* Set thresholds array to NULL if we don't have thresholds */
3504 /* Copy thresholds and find current threshold */
3505 new->current_threshold
= -1;
3506 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
3507 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
3510 new->entries
[j
] = thresholds
->primary
->entries
[i
];
3511 if (new->entries
[j
].threshold
<= usage
) {
3513 * new->current_threshold will not be used
3514 * until rcu_assign_pointer(), so it's safe to increment
3517 ++new->current_threshold
;
3523 /* Swap primary and spare array */
3524 thresholds
->spare
= thresholds
->primary
;
3526 rcu_assign_pointer(thresholds
->primary
, new);
3528 /* To be sure that nobody uses thresholds */
3531 /* If all events are unregistered, free the spare array */
3533 kfree(thresholds
->spare
);
3534 thresholds
->spare
= NULL
;
3537 mutex_unlock(&memcg
->thresholds_lock
);
3540 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3541 struct eventfd_ctx
*eventfd
)
3543 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
3546 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
3547 struct eventfd_ctx
*eventfd
)
3549 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
3552 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
3553 struct eventfd_ctx
*eventfd
, const char *args
)
3555 struct mem_cgroup_eventfd_list
*event
;
3557 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
3561 spin_lock(&memcg_oom_lock
);
3563 event
->eventfd
= eventfd
;
3564 list_add(&event
->list
, &memcg
->oom_notify
);
3566 /* already in OOM ? */
3567 if (memcg
->under_oom
)
3568 eventfd_signal(eventfd
, 1);
3569 spin_unlock(&memcg_oom_lock
);
3574 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
3575 struct eventfd_ctx
*eventfd
)
3577 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
3579 spin_lock(&memcg_oom_lock
);
3581 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
3582 if (ev
->eventfd
== eventfd
) {
3583 list_del(&ev
->list
);
3588 spin_unlock(&memcg_oom_lock
);
3591 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
3593 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(sf
));
3595 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
3596 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
3597 seq_printf(sf
, "oom_kill %lu\n", memcg_sum_events(memcg
, OOM_KILL
));
3601 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
3602 struct cftype
*cft
, u64 val
)
3604 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3606 /* cannot set to root cgroup and only 0 and 1 are allowed */
3607 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
3610 memcg
->oom_kill_disable
= val
;
3612 memcg_oom_recover(memcg
);
3617 #ifdef CONFIG_CGROUP_WRITEBACK
3619 struct list_head
*mem_cgroup_cgwb_list(struct mem_cgroup
*memcg
)
3621 return &memcg
->cgwb_list
;
3624 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3626 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
3629 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3631 wb_domain_exit(&memcg
->cgwb_domain
);
3634 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3636 wb_domain_size_changed(&memcg
->cgwb_domain
);
3639 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
3641 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3643 if (!memcg
->css
.parent
)
3646 return &memcg
->cgwb_domain
;
3650 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
3651 * @wb: bdi_writeback in question
3652 * @pfilepages: out parameter for number of file pages
3653 * @pheadroom: out parameter for number of allocatable pages according to memcg
3654 * @pdirty: out parameter for number of dirty pages
3655 * @pwriteback: out parameter for number of pages under writeback
3657 * Determine the numbers of file, headroom, dirty, and writeback pages in
3658 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
3659 * is a bit more involved.
3661 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
3662 * headroom is calculated as the lowest headroom of itself and the
3663 * ancestors. Note that this doesn't consider the actual amount of
3664 * available memory in the system. The caller should further cap
3665 * *@pheadroom accordingly.
3667 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
3668 unsigned long *pheadroom
, unsigned long *pdirty
,
3669 unsigned long *pwriteback
)
3671 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
3672 struct mem_cgroup
*parent
;
3674 *pdirty
= memcg_page_state(memcg
, NR_FILE_DIRTY
);
3676 /* this should eventually include NR_UNSTABLE_NFS */
3677 *pwriteback
= memcg_page_state(memcg
, NR_WRITEBACK
);
3678 *pfilepages
= mem_cgroup_nr_lru_pages(memcg
, (1 << LRU_INACTIVE_FILE
) |
3679 (1 << LRU_ACTIVE_FILE
));
3680 *pheadroom
= PAGE_COUNTER_MAX
;
3682 while ((parent
= parent_mem_cgroup(memcg
))) {
3683 unsigned long ceiling
= min(memcg
->memory
.limit
, memcg
->high
);
3684 unsigned long used
= page_counter_read(&memcg
->memory
);
3686 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
3691 #else /* CONFIG_CGROUP_WRITEBACK */
3693 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
3698 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
3702 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
3706 #endif /* CONFIG_CGROUP_WRITEBACK */
3709 * DO NOT USE IN NEW FILES.
3711 * "cgroup.event_control" implementation.
3713 * This is way over-engineered. It tries to support fully configurable
3714 * events for each user. Such level of flexibility is completely
3715 * unnecessary especially in the light of the planned unified hierarchy.
3717 * Please deprecate this and replace with something simpler if at all
3722 * Unregister event and free resources.
3724 * Gets called from workqueue.
3726 static void memcg_event_remove(struct work_struct
*work
)
3728 struct mem_cgroup_event
*event
=
3729 container_of(work
, struct mem_cgroup_event
, remove
);
3730 struct mem_cgroup
*memcg
= event
->memcg
;
3732 remove_wait_queue(event
->wqh
, &event
->wait
);
3734 event
->unregister_event(memcg
, event
->eventfd
);
3736 /* Notify userspace the event is going away. */
3737 eventfd_signal(event
->eventfd
, 1);
3739 eventfd_ctx_put(event
->eventfd
);
3741 css_put(&memcg
->css
);
3745 * Gets called on POLLHUP on eventfd when user closes it.
3747 * Called with wqh->lock held and interrupts disabled.
3749 static int memcg_event_wake(wait_queue_entry_t
*wait
, unsigned mode
,
3750 int sync
, void *key
)
3752 struct mem_cgroup_event
*event
=
3753 container_of(wait
, struct mem_cgroup_event
, wait
);
3754 struct mem_cgroup
*memcg
= event
->memcg
;
3755 unsigned long flags
= (unsigned long)key
;
3757 if (flags
& POLLHUP
) {
3759 * If the event has been detached at cgroup removal, we
3760 * can simply return knowing the other side will cleanup
3763 * We can't race against event freeing since the other
3764 * side will require wqh->lock via remove_wait_queue(),
3767 spin_lock(&memcg
->event_list_lock
);
3768 if (!list_empty(&event
->list
)) {
3769 list_del_init(&event
->list
);
3771 * We are in atomic context, but cgroup_event_remove()
3772 * may sleep, so we have to call it in workqueue.
3774 schedule_work(&event
->remove
);
3776 spin_unlock(&memcg
->event_list_lock
);
3782 static void memcg_event_ptable_queue_proc(struct file
*file
,
3783 wait_queue_head_t
*wqh
, poll_table
*pt
)
3785 struct mem_cgroup_event
*event
=
3786 container_of(pt
, struct mem_cgroup_event
, pt
);
3789 add_wait_queue(wqh
, &event
->wait
);
3793 * DO NOT USE IN NEW FILES.
3795 * Parse input and register new cgroup event handler.
3797 * Input must be in format '<event_fd> <control_fd> <args>'.
3798 * Interpretation of args is defined by control file implementation.
3800 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
3801 char *buf
, size_t nbytes
, loff_t off
)
3803 struct cgroup_subsys_state
*css
= of_css(of
);
3804 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3805 struct mem_cgroup_event
*event
;
3806 struct cgroup_subsys_state
*cfile_css
;
3807 unsigned int efd
, cfd
;
3814 buf
= strstrip(buf
);
3816 efd
= simple_strtoul(buf
, &endp
, 10);
3821 cfd
= simple_strtoul(buf
, &endp
, 10);
3822 if ((*endp
!= ' ') && (*endp
!= '\0'))
3826 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
3830 event
->memcg
= memcg
;
3831 INIT_LIST_HEAD(&event
->list
);
3832 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
3833 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
3834 INIT_WORK(&event
->remove
, memcg_event_remove
);
3842 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
3843 if (IS_ERR(event
->eventfd
)) {
3844 ret
= PTR_ERR(event
->eventfd
);
3851 goto out_put_eventfd
;
3854 /* the process need read permission on control file */
3855 /* AV: shouldn't we check that it's been opened for read instead? */
3856 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
3861 * Determine the event callbacks and set them in @event. This used
3862 * to be done via struct cftype but cgroup core no longer knows
3863 * about these events. The following is crude but the whole thing
3864 * is for compatibility anyway.
3866 * DO NOT ADD NEW FILES.
3868 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
3870 if (!strcmp(name
, "memory.usage_in_bytes")) {
3871 event
->register_event
= mem_cgroup_usage_register_event
;
3872 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
3873 } else if (!strcmp(name
, "memory.oom_control")) {
3874 event
->register_event
= mem_cgroup_oom_register_event
;
3875 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
3876 } else if (!strcmp(name
, "memory.pressure_level")) {
3877 event
->register_event
= vmpressure_register_event
;
3878 event
->unregister_event
= vmpressure_unregister_event
;
3879 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
3880 event
->register_event
= memsw_cgroup_usage_register_event
;
3881 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
3888 * Verify @cfile should belong to @css. Also, remaining events are
3889 * automatically removed on cgroup destruction but the removal is
3890 * asynchronous, so take an extra ref on @css.
3892 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
3893 &memory_cgrp_subsys
);
3895 if (IS_ERR(cfile_css
))
3897 if (cfile_css
!= css
) {
3902 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
3906 efile
.file
->f_op
->poll(efile
.file
, &event
->pt
);
3908 spin_lock(&memcg
->event_list_lock
);
3909 list_add(&event
->list
, &memcg
->event_list
);
3910 spin_unlock(&memcg
->event_list_lock
);
3922 eventfd_ctx_put(event
->eventfd
);
3931 static struct cftype mem_cgroup_legacy_files
[] = {
3933 .name
= "usage_in_bytes",
3934 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
3935 .read_u64
= mem_cgroup_read_u64
,
3938 .name
= "max_usage_in_bytes",
3939 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
3940 .write
= mem_cgroup_reset
,
3941 .read_u64
= mem_cgroup_read_u64
,
3944 .name
= "limit_in_bytes",
3945 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
3946 .write
= mem_cgroup_write
,
3947 .read_u64
= mem_cgroup_read_u64
,
3950 .name
= "soft_limit_in_bytes",
3951 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
3952 .write
= mem_cgroup_write
,
3953 .read_u64
= mem_cgroup_read_u64
,
3957 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
3958 .write
= mem_cgroup_reset
,
3959 .read_u64
= mem_cgroup_read_u64
,
3963 .seq_show
= memcg_stat_show
,
3966 .name
= "force_empty",
3967 .write
= mem_cgroup_force_empty_write
,
3970 .name
= "use_hierarchy",
3971 .write_u64
= mem_cgroup_hierarchy_write
,
3972 .read_u64
= mem_cgroup_hierarchy_read
,
3975 .name
= "cgroup.event_control", /* XXX: for compat */
3976 .write
= memcg_write_event_control
,
3977 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
3980 .name
= "swappiness",
3981 .read_u64
= mem_cgroup_swappiness_read
,
3982 .write_u64
= mem_cgroup_swappiness_write
,
3985 .name
= "move_charge_at_immigrate",
3986 .read_u64
= mem_cgroup_move_charge_read
,
3987 .write_u64
= mem_cgroup_move_charge_write
,
3990 .name
= "oom_control",
3991 .seq_show
= mem_cgroup_oom_control_read
,
3992 .write_u64
= mem_cgroup_oom_control_write
,
3993 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
3996 .name
= "pressure_level",
4000 .name
= "numa_stat",
4001 .seq_show
= memcg_numa_stat_show
,
4005 .name
= "kmem.limit_in_bytes",
4006 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4007 .write
= mem_cgroup_write
,
4008 .read_u64
= mem_cgroup_read_u64
,
4011 .name
= "kmem.usage_in_bytes",
4012 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4013 .read_u64
= mem_cgroup_read_u64
,
4016 .name
= "kmem.failcnt",
4017 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
4018 .write
= mem_cgroup_reset
,
4019 .read_u64
= mem_cgroup_read_u64
,
4022 .name
= "kmem.max_usage_in_bytes",
4023 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4024 .write
= mem_cgroup_reset
,
4025 .read_u64
= mem_cgroup_read_u64
,
4027 #ifdef CONFIG_SLABINFO
4029 .name
= "kmem.slabinfo",
4030 .seq_start
= memcg_slab_start
,
4031 .seq_next
= memcg_slab_next
,
4032 .seq_stop
= memcg_slab_stop
,
4033 .seq_show
= memcg_slab_show
,
4037 .name
= "kmem.tcp.limit_in_bytes",
4038 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4039 .write
= mem_cgroup_write
,
4040 .read_u64
= mem_cgroup_read_u64
,
4043 .name
= "kmem.tcp.usage_in_bytes",
4044 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4045 .read_u64
= mem_cgroup_read_u64
,
4048 .name
= "kmem.tcp.failcnt",
4049 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4050 .write
= mem_cgroup_reset
,
4051 .read_u64
= mem_cgroup_read_u64
,
4054 .name
= "kmem.tcp.max_usage_in_bytes",
4055 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4056 .write
= mem_cgroup_reset
,
4057 .read_u64
= mem_cgroup_read_u64
,
4059 { }, /* terminate */
4063 * Private memory cgroup IDR
4065 * Swap-out records and page cache shadow entries need to store memcg
4066 * references in constrained space, so we maintain an ID space that is
4067 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4068 * memory-controlled cgroups to 64k.
4070 * However, there usually are many references to the oflline CSS after
4071 * the cgroup has been destroyed, such as page cache or reclaimable
4072 * slab objects, that don't need to hang on to the ID. We want to keep
4073 * those dead CSS from occupying IDs, or we might quickly exhaust the
4074 * relatively small ID space and prevent the creation of new cgroups
4075 * even when there are much fewer than 64k cgroups - possibly none.
4077 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4078 * be freed and recycled when it's no longer needed, which is usually
4079 * when the CSS is offlined.
4081 * The only exception to that are records of swapped out tmpfs/shmem
4082 * pages that need to be attributed to live ancestors on swapin. But
4083 * those references are manageable from userspace.
4086 static DEFINE_IDR(mem_cgroup_idr
);
4088 static void mem_cgroup_id_get_many(struct mem_cgroup
*memcg
, unsigned int n
)
4090 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) <= 0);
4091 atomic_add(n
, &memcg
->id
.ref
);
4094 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
4096 VM_BUG_ON(atomic_read(&memcg
->id
.ref
) < n
);
4097 if (atomic_sub_and_test(n
, &memcg
->id
.ref
)) {
4098 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4101 /* Memcg ID pins CSS */
4102 css_put(&memcg
->css
);
4106 static inline void mem_cgroup_id_get(struct mem_cgroup
*memcg
)
4108 mem_cgroup_id_get_many(memcg
, 1);
4111 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
4113 mem_cgroup_id_put_many(memcg
, 1);
4117 * mem_cgroup_from_id - look up a memcg from a memcg id
4118 * @id: the memcg id to look up
4120 * Caller must hold rcu_read_lock().
4122 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
4124 WARN_ON_ONCE(!rcu_read_lock_held());
4125 return idr_find(&mem_cgroup_idr
, id
);
4128 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4130 struct mem_cgroup_per_node
*pn
;
4133 * This routine is called against possible nodes.
4134 * But it's BUG to call kmalloc() against offline node.
4136 * TODO: this routine can waste much memory for nodes which will
4137 * never be onlined. It's better to use memory hotplug callback
4140 if (!node_state(node
, N_NORMAL_MEMORY
))
4142 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4146 pn
->lruvec_stat
= alloc_percpu(struct lruvec_stat
);
4147 if (!pn
->lruvec_stat
) {
4152 lruvec_init(&pn
->lruvec
);
4153 pn
->usage_in_excess
= 0;
4154 pn
->on_tree
= false;
4157 memcg
->nodeinfo
[node
] = pn
;
4161 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4163 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
4165 free_percpu(pn
->lruvec_stat
);
4169 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
4174 free_mem_cgroup_per_node_info(memcg
, node
);
4175 free_percpu(memcg
->stat
);
4179 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
4181 memcg_wb_domain_exit(memcg
);
4182 __mem_cgroup_free(memcg
);
4185 static struct mem_cgroup
*mem_cgroup_alloc(void)
4187 struct mem_cgroup
*memcg
;
4191 size
= sizeof(struct mem_cgroup
);
4192 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
4194 memcg
= kzalloc(size
, GFP_KERNEL
);
4198 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
4199 1, MEM_CGROUP_ID_MAX
,
4201 if (memcg
->id
.id
< 0)
4204 memcg
->stat
= alloc_percpu(struct mem_cgroup_stat_cpu
);
4209 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
4212 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
4215 INIT_WORK(&memcg
->high_work
, high_work_func
);
4216 memcg
->last_scanned_node
= MAX_NUMNODES
;
4217 INIT_LIST_HEAD(&memcg
->oom_notify
);
4218 mutex_init(&memcg
->thresholds_lock
);
4219 spin_lock_init(&memcg
->move_lock
);
4220 vmpressure_init(&memcg
->vmpressure
);
4221 INIT_LIST_HEAD(&memcg
->event_list
);
4222 spin_lock_init(&memcg
->event_list_lock
);
4223 memcg
->socket_pressure
= jiffies
;
4225 memcg
->kmemcg_id
= -1;
4227 #ifdef CONFIG_CGROUP_WRITEBACK
4228 INIT_LIST_HEAD(&memcg
->cgwb_list
);
4230 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
4233 if (memcg
->id
.id
> 0)
4234 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4235 __mem_cgroup_free(memcg
);
4239 static struct cgroup_subsys_state
* __ref
4240 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
4242 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
4243 struct mem_cgroup
*memcg
;
4244 long error
= -ENOMEM
;
4246 memcg
= mem_cgroup_alloc();
4248 return ERR_PTR(error
);
4250 memcg
->high
= PAGE_COUNTER_MAX
;
4251 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4253 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
4254 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
4256 if (parent
&& parent
->use_hierarchy
) {
4257 memcg
->use_hierarchy
= true;
4258 page_counter_init(&memcg
->memory
, &parent
->memory
);
4259 page_counter_init(&memcg
->swap
, &parent
->swap
);
4260 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
4261 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
4262 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
4264 page_counter_init(&memcg
->memory
, NULL
);
4265 page_counter_init(&memcg
->swap
, NULL
);
4266 page_counter_init(&memcg
->memsw
, NULL
);
4267 page_counter_init(&memcg
->kmem
, NULL
);
4268 page_counter_init(&memcg
->tcpmem
, NULL
);
4270 * Deeper hierachy with use_hierarchy == false doesn't make
4271 * much sense so let cgroup subsystem know about this
4272 * unfortunate state in our controller.
4274 if (parent
!= root_mem_cgroup
)
4275 memory_cgrp_subsys
.broken_hierarchy
= true;
4278 /* The following stuff does not apply to the root */
4280 root_mem_cgroup
= memcg
;
4284 error
= memcg_online_kmem(memcg
);
4288 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4289 static_branch_inc(&memcg_sockets_enabled_key
);
4293 mem_cgroup_free(memcg
);
4294 return ERR_PTR(-ENOMEM
);
4297 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
4299 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4301 /* Online state pins memcg ID, memcg ID pins CSS */
4302 atomic_set(&memcg
->id
.ref
, 1);
4307 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
4309 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4310 struct mem_cgroup_event
*event
, *tmp
;
4313 * Unregister events and notify userspace.
4314 * Notify userspace about cgroup removing only after rmdir of cgroup
4315 * directory to avoid race between userspace and kernelspace.
4317 spin_lock(&memcg
->event_list_lock
);
4318 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
4319 list_del_init(&event
->list
);
4320 schedule_work(&event
->remove
);
4322 spin_unlock(&memcg
->event_list_lock
);
4326 memcg_offline_kmem(memcg
);
4327 wb_memcg_offline(memcg
);
4329 mem_cgroup_id_put(memcg
);
4332 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
4334 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4336 invalidate_reclaim_iterators(memcg
);
4339 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
4341 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4343 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
4344 static_branch_dec(&memcg_sockets_enabled_key
);
4346 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
4347 static_branch_dec(&memcg_sockets_enabled_key
);
4349 vmpressure_cleanup(&memcg
->vmpressure
);
4350 cancel_work_sync(&memcg
->high_work
);
4351 mem_cgroup_remove_from_trees(memcg
);
4352 memcg_free_kmem(memcg
);
4353 mem_cgroup_free(memcg
);
4357 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4358 * @css: the target css
4360 * Reset the states of the mem_cgroup associated with @css. This is
4361 * invoked when the userland requests disabling on the default hierarchy
4362 * but the memcg is pinned through dependency. The memcg should stop
4363 * applying policies and should revert to the vanilla state as it may be
4364 * made visible again.
4366 * The current implementation only resets the essential configurations.
4367 * This needs to be expanded to cover all the visible parts.
4369 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
4371 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4373 page_counter_limit(&memcg
->memory
, PAGE_COUNTER_MAX
);
4374 page_counter_limit(&memcg
->swap
, PAGE_COUNTER_MAX
);
4375 page_counter_limit(&memcg
->memsw
, PAGE_COUNTER_MAX
);
4376 page_counter_limit(&memcg
->kmem
, PAGE_COUNTER_MAX
);
4377 page_counter_limit(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
4379 memcg
->high
= PAGE_COUNTER_MAX
;
4380 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
4381 memcg_wb_domain_size_changed(memcg
);
4385 /* Handlers for move charge at task migration. */
4386 static int mem_cgroup_do_precharge(unsigned long count
)
4390 /* Try a single bulk charge without reclaim first, kswapd may wake */
4391 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
4393 mc
.precharge
+= count
;
4397 /* Try charges one by one with reclaim, but do not retry */
4399 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
4413 enum mc_target_type
{
4419 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
4420 unsigned long addr
, pte_t ptent
)
4422 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
4424 if (!page
|| !page_mapped(page
))
4426 if (PageAnon(page
)) {
4427 if (!(mc
.flags
& MOVE_ANON
))
4430 if (!(mc
.flags
& MOVE_FILE
))
4433 if (!get_page_unless_zero(page
))
4440 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4441 pte_t ptent
, swp_entry_t
*entry
)
4443 struct page
*page
= NULL
;
4444 swp_entry_t ent
= pte_to_swp_entry(ptent
);
4446 if (!(mc
.flags
& MOVE_ANON
) || non_swap_entry(ent
))
4449 * Because lookup_swap_cache() updates some statistics counter,
4450 * we call find_get_page() with swapper_space directly.
4452 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
4453 if (do_memsw_account())
4454 entry
->val
= ent
.val
;
4459 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
4460 pte_t ptent
, swp_entry_t
*entry
)
4466 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
4467 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
4469 struct page
*page
= NULL
;
4470 struct address_space
*mapping
;
4473 if (!vma
->vm_file
) /* anonymous vma */
4475 if (!(mc
.flags
& MOVE_FILE
))
4478 mapping
= vma
->vm_file
->f_mapping
;
4479 pgoff
= linear_page_index(vma
, addr
);
4481 /* page is moved even if it's not RSS of this task(page-faulted). */
4483 /* shmem/tmpfs may report page out on swap: account for that too. */
4484 if (shmem_mapping(mapping
)) {
4485 page
= find_get_entry(mapping
, pgoff
);
4486 if (radix_tree_exceptional_entry(page
)) {
4487 swp_entry_t swp
= radix_to_swp_entry(page
);
4488 if (do_memsw_account())
4490 page
= find_get_page(swap_address_space(swp
),
4494 page
= find_get_page(mapping
, pgoff
);
4496 page
= find_get_page(mapping
, pgoff
);
4502 * mem_cgroup_move_account - move account of the page
4504 * @compound: charge the page as compound or small page
4505 * @from: mem_cgroup which the page is moved from.
4506 * @to: mem_cgroup which the page is moved to. @from != @to.
4508 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
4510 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
4513 static int mem_cgroup_move_account(struct page
*page
,
4515 struct mem_cgroup
*from
,
4516 struct mem_cgroup
*to
)
4518 unsigned long flags
;
4519 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
4523 VM_BUG_ON(from
== to
);
4524 VM_BUG_ON_PAGE(PageLRU(page
), page
);
4525 VM_BUG_ON(compound
&& !PageTransHuge(page
));
4528 * Prevent mem_cgroup_migrate() from looking at
4529 * page->mem_cgroup of its source page while we change it.
4532 if (!trylock_page(page
))
4536 if (page
->mem_cgroup
!= from
)
4539 anon
= PageAnon(page
);
4541 spin_lock_irqsave(&from
->move_lock
, flags
);
4543 if (!anon
&& page_mapped(page
)) {
4544 __this_cpu_sub(from
->stat
->count
[NR_FILE_MAPPED
], nr_pages
);
4545 __this_cpu_add(to
->stat
->count
[NR_FILE_MAPPED
], nr_pages
);
4549 * move_lock grabbed above and caller set from->moving_account, so
4550 * mod_memcg_page_state will serialize updates to PageDirty.
4551 * So mapping should be stable for dirty pages.
4553 if (!anon
&& PageDirty(page
)) {
4554 struct address_space
*mapping
= page_mapping(page
);
4556 if (mapping_cap_account_dirty(mapping
)) {
4557 __this_cpu_sub(from
->stat
->count
[NR_FILE_DIRTY
],
4559 __this_cpu_add(to
->stat
->count
[NR_FILE_DIRTY
],
4564 if (PageWriteback(page
)) {
4565 __this_cpu_sub(from
->stat
->count
[NR_WRITEBACK
], nr_pages
);
4566 __this_cpu_add(to
->stat
->count
[NR_WRITEBACK
], nr_pages
);
4570 * It is safe to change page->mem_cgroup here because the page
4571 * is referenced, charged, and isolated - we can't race with
4572 * uncharging, charging, migration, or LRU putback.
4575 /* caller should have done css_get */
4576 page
->mem_cgroup
= to
;
4577 spin_unlock_irqrestore(&from
->move_lock
, flags
);
4581 local_irq_disable();
4582 mem_cgroup_charge_statistics(to
, page
, compound
, nr_pages
);
4583 memcg_check_events(to
, page
);
4584 mem_cgroup_charge_statistics(from
, page
, compound
, -nr_pages
);
4585 memcg_check_events(from
, page
);
4594 * get_mctgt_type - get target type of moving charge
4595 * @vma: the vma the pte to be checked belongs
4596 * @addr: the address corresponding to the pte to be checked
4597 * @ptent: the pte to be checked
4598 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4601 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4602 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4603 * move charge. if @target is not NULL, the page is stored in target->page
4604 * with extra refcnt got(Callers should handle it).
4605 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4606 * target for charge migration. if @target is not NULL, the entry is stored
4609 * Called with pte lock held.
4612 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
4613 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
4615 struct page
*page
= NULL
;
4616 enum mc_target_type ret
= MC_TARGET_NONE
;
4617 swp_entry_t ent
= { .val
= 0 };
4619 if (pte_present(ptent
))
4620 page
= mc_handle_present_pte(vma
, addr
, ptent
);
4621 else if (is_swap_pte(ptent
))
4622 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
4623 else if (pte_none(ptent
))
4624 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
4626 if (!page
&& !ent
.val
)
4630 * Do only loose check w/o serialization.
4631 * mem_cgroup_move_account() checks the page is valid or
4632 * not under LRU exclusion.
4634 if (page
->mem_cgroup
== mc
.from
) {
4635 ret
= MC_TARGET_PAGE
;
4637 target
->page
= page
;
4639 if (!ret
|| !target
)
4643 * There is a swap entry and a page doesn't exist or isn't charged.
4644 * But we cannot move a tail-page in a THP.
4646 if (ent
.val
&& !ret
&& (!page
|| !PageTransCompound(page
)) &&
4647 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
4648 ret
= MC_TARGET_SWAP
;
4655 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4657 * We don't consider PMD mapped swapping or file mapped pages because THP does
4658 * not support them for now.
4659 * Caller should make sure that pmd_trans_huge(pmd) is true.
4661 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4662 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4664 struct page
*page
= NULL
;
4665 enum mc_target_type ret
= MC_TARGET_NONE
;
4667 page
= pmd_page(pmd
);
4668 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
4669 if (!(mc
.flags
& MOVE_ANON
))
4671 if (page
->mem_cgroup
== mc
.from
) {
4672 ret
= MC_TARGET_PAGE
;
4675 target
->page
= page
;
4681 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
4682 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
4684 return MC_TARGET_NONE
;
4688 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
4689 unsigned long addr
, unsigned long end
,
4690 struct mm_walk
*walk
)
4692 struct vm_area_struct
*vma
= walk
->vma
;
4696 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4698 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
4699 mc
.precharge
+= HPAGE_PMD_NR
;
4704 if (pmd_trans_unstable(pmd
))
4706 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4707 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
4708 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
4709 mc
.precharge
++; /* increment precharge temporarily */
4710 pte_unmap_unlock(pte
- 1, ptl
);
4716 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
4718 unsigned long precharge
;
4720 struct mm_walk mem_cgroup_count_precharge_walk
= {
4721 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
4724 down_read(&mm
->mmap_sem
);
4725 walk_page_range(0, mm
->highest_vm_end
,
4726 &mem_cgroup_count_precharge_walk
);
4727 up_read(&mm
->mmap_sem
);
4729 precharge
= mc
.precharge
;
4735 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
4737 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
4739 VM_BUG_ON(mc
.moving_task
);
4740 mc
.moving_task
= current
;
4741 return mem_cgroup_do_precharge(precharge
);
4744 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4745 static void __mem_cgroup_clear_mc(void)
4747 struct mem_cgroup
*from
= mc
.from
;
4748 struct mem_cgroup
*to
= mc
.to
;
4750 /* we must uncharge all the leftover precharges from mc.to */
4752 cancel_charge(mc
.to
, mc
.precharge
);
4756 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4757 * we must uncharge here.
4759 if (mc
.moved_charge
) {
4760 cancel_charge(mc
.from
, mc
.moved_charge
);
4761 mc
.moved_charge
= 0;
4763 /* we must fixup refcnts and charges */
4764 if (mc
.moved_swap
) {
4765 /* uncharge swap account from the old cgroup */
4766 if (!mem_cgroup_is_root(mc
.from
))
4767 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
4769 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
4772 * we charged both to->memory and to->memsw, so we
4773 * should uncharge to->memory.
4775 if (!mem_cgroup_is_root(mc
.to
))
4776 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
4778 mem_cgroup_id_get_many(mc
.to
, mc
.moved_swap
);
4779 css_put_many(&mc
.to
->css
, mc
.moved_swap
);
4783 memcg_oom_recover(from
);
4784 memcg_oom_recover(to
);
4785 wake_up_all(&mc
.waitq
);
4788 static void mem_cgroup_clear_mc(void)
4790 struct mm_struct
*mm
= mc
.mm
;
4793 * we must clear moving_task before waking up waiters at the end of
4796 mc
.moving_task
= NULL
;
4797 __mem_cgroup_clear_mc();
4798 spin_lock(&mc
.lock
);
4802 spin_unlock(&mc
.lock
);
4807 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
4809 struct cgroup_subsys_state
*css
;
4810 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
4811 struct mem_cgroup
*from
;
4812 struct task_struct
*leader
, *p
;
4813 struct mm_struct
*mm
;
4814 unsigned long move_flags
;
4817 /* charge immigration isn't supported on the default hierarchy */
4818 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
4822 * Multi-process migrations only happen on the default hierarchy
4823 * where charge immigration is not used. Perform charge
4824 * immigration if @tset contains a leader and whine if there are
4828 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
4831 memcg
= mem_cgroup_from_css(css
);
4837 * We are now commited to this value whatever it is. Changes in this
4838 * tunable will only affect upcoming migrations, not the current one.
4839 * So we need to save it, and keep it going.
4841 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
4845 from
= mem_cgroup_from_task(p
);
4847 VM_BUG_ON(from
== memcg
);
4849 mm
= get_task_mm(p
);
4852 /* We move charges only when we move a owner of the mm */
4853 if (mm
->owner
== p
) {
4856 VM_BUG_ON(mc
.precharge
);
4857 VM_BUG_ON(mc
.moved_charge
);
4858 VM_BUG_ON(mc
.moved_swap
);
4860 spin_lock(&mc
.lock
);
4864 mc
.flags
= move_flags
;
4865 spin_unlock(&mc
.lock
);
4866 /* We set mc.moving_task later */
4868 ret
= mem_cgroup_precharge_mc(mm
);
4870 mem_cgroup_clear_mc();
4877 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
4880 mem_cgroup_clear_mc();
4883 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
4884 unsigned long addr
, unsigned long end
,
4885 struct mm_walk
*walk
)
4888 struct vm_area_struct
*vma
= walk
->vma
;
4891 enum mc_target_type target_type
;
4892 union mc_target target
;
4895 ptl
= pmd_trans_huge_lock(pmd
, vma
);
4897 if (mc
.precharge
< HPAGE_PMD_NR
) {
4901 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
4902 if (target_type
== MC_TARGET_PAGE
) {
4904 if (!isolate_lru_page(page
)) {
4905 if (!mem_cgroup_move_account(page
, true,
4907 mc
.precharge
-= HPAGE_PMD_NR
;
4908 mc
.moved_charge
+= HPAGE_PMD_NR
;
4910 putback_lru_page(page
);
4918 if (pmd_trans_unstable(pmd
))
4921 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
4922 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
4923 pte_t ptent
= *(pte
++);
4929 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
4930 case MC_TARGET_PAGE
:
4933 * We can have a part of the split pmd here. Moving it
4934 * can be done but it would be too convoluted so simply
4935 * ignore such a partial THP and keep it in original
4936 * memcg. There should be somebody mapping the head.
4938 if (PageTransCompound(page
))
4940 if (isolate_lru_page(page
))
4942 if (!mem_cgroup_move_account(page
, false,
4945 /* we uncharge from mc.from later. */
4948 putback_lru_page(page
);
4949 put
: /* get_mctgt_type() gets the page */
4952 case MC_TARGET_SWAP
:
4954 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
4956 /* we fixup refcnts and charges later. */
4964 pte_unmap_unlock(pte
- 1, ptl
);
4969 * We have consumed all precharges we got in can_attach().
4970 * We try charge one by one, but don't do any additional
4971 * charges to mc.to if we have failed in charge once in attach()
4974 ret
= mem_cgroup_do_precharge(1);
4982 static void mem_cgroup_move_charge(void)
4984 struct mm_walk mem_cgroup_move_charge_walk
= {
4985 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
4989 lru_add_drain_all();
4991 * Signal lock_page_memcg() to take the memcg's move_lock
4992 * while we're moving its pages to another memcg. Then wait
4993 * for already started RCU-only updates to finish.
4995 atomic_inc(&mc
.from
->moving_account
);
4998 if (unlikely(!down_read_trylock(&mc
.mm
->mmap_sem
))) {
5000 * Someone who are holding the mmap_sem might be waiting in
5001 * waitq. So we cancel all extra charges, wake up all waiters,
5002 * and retry. Because we cancel precharges, we might not be able
5003 * to move enough charges, but moving charge is a best-effort
5004 * feature anyway, so it wouldn't be a big problem.
5006 __mem_cgroup_clear_mc();
5011 * When we have consumed all precharges and failed in doing
5012 * additional charge, the page walk just aborts.
5014 walk_page_range(0, mc
.mm
->highest_vm_end
, &mem_cgroup_move_charge_walk
);
5016 up_read(&mc
.mm
->mmap_sem
);
5017 atomic_dec(&mc
.from
->moving_account
);
5020 static void mem_cgroup_move_task(void)
5023 mem_cgroup_move_charge();
5024 mem_cgroup_clear_mc();
5027 #else /* !CONFIG_MMU */
5028 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5032 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5035 static void mem_cgroup_move_task(void)
5041 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5042 * to verify whether we're attached to the default hierarchy on each mount
5045 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5048 * use_hierarchy is forced on the default hierarchy. cgroup core
5049 * guarantees that @root doesn't have any children, so turning it
5050 * on for the root memcg is enough.
5052 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5053 root_mem_cgroup
->use_hierarchy
= true;
5055 root_mem_cgroup
->use_hierarchy
= false;
5058 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
5061 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5063 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
5066 static int memory_low_show(struct seq_file
*m
, void *v
)
5068 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5069 unsigned long low
= READ_ONCE(memcg
->low
);
5071 if (low
== PAGE_COUNTER_MAX
)
5072 seq_puts(m
, "max\n");
5074 seq_printf(m
, "%llu\n", (u64
)low
* PAGE_SIZE
);
5079 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
5080 char *buf
, size_t nbytes
, loff_t off
)
5082 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5086 buf
= strstrip(buf
);
5087 err
= page_counter_memparse(buf
, "max", &low
);
5096 static int memory_high_show(struct seq_file
*m
, void *v
)
5098 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5099 unsigned long high
= READ_ONCE(memcg
->high
);
5101 if (high
== PAGE_COUNTER_MAX
)
5102 seq_puts(m
, "max\n");
5104 seq_printf(m
, "%llu\n", (u64
)high
* PAGE_SIZE
);
5109 static ssize_t
memory_high_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 long nr_pages
;
5117 buf
= strstrip(buf
);
5118 err
= page_counter_memparse(buf
, "max", &high
);
5124 nr_pages
= page_counter_read(&memcg
->memory
);
5125 if (nr_pages
> high
)
5126 try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
5129 memcg_wb_domain_size_changed(memcg
);
5133 static int memory_max_show(struct seq_file
*m
, void *v
)
5135 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5136 unsigned long max
= READ_ONCE(memcg
->memory
.limit
);
5138 if (max
== PAGE_COUNTER_MAX
)
5139 seq_puts(m
, "max\n");
5141 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
5146 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
5147 char *buf
, size_t nbytes
, loff_t off
)
5149 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5150 unsigned int nr_reclaims
= MEM_CGROUP_RECLAIM_RETRIES
;
5151 bool drained
= false;
5155 buf
= strstrip(buf
);
5156 err
= page_counter_memparse(buf
, "max", &max
);
5160 xchg(&memcg
->memory
.limit
, max
);
5163 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
5165 if (nr_pages
<= max
)
5168 if (signal_pending(current
)) {
5174 drain_all_stock(memcg
);
5180 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
5186 mem_cgroup_event(memcg
, MEMCG_OOM
);
5187 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
5191 memcg_wb_domain_size_changed(memcg
);
5195 static int memory_events_show(struct seq_file
*m
, void *v
)
5197 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5199 seq_printf(m
, "low %lu\n", memcg_sum_events(memcg
, MEMCG_LOW
));
5200 seq_printf(m
, "high %lu\n", memcg_sum_events(memcg
, MEMCG_HIGH
));
5201 seq_printf(m
, "max %lu\n", memcg_sum_events(memcg
, MEMCG_MAX
));
5202 seq_printf(m
, "oom %lu\n", memcg_sum_events(memcg
, MEMCG_OOM
));
5203 seq_printf(m
, "oom_kill %lu\n", memcg_sum_events(memcg
, OOM_KILL
));
5208 static int memory_stat_show(struct seq_file
*m
, void *v
)
5210 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
5211 unsigned long stat
[MEMCG_NR_STAT
];
5212 unsigned long events
[MEMCG_NR_EVENTS
];
5216 * Provide statistics on the state of the memory subsystem as
5217 * well as cumulative event counters that show past behavior.
5219 * This list is ordered following a combination of these gradients:
5220 * 1) generic big picture -> specifics and details
5221 * 2) reflecting userspace activity -> reflecting kernel heuristics
5223 * Current memory state:
5226 tree_stat(memcg
, stat
);
5227 tree_events(memcg
, events
);
5229 seq_printf(m
, "anon %llu\n",
5230 (u64
)stat
[MEMCG_RSS
] * PAGE_SIZE
);
5231 seq_printf(m
, "file %llu\n",
5232 (u64
)stat
[MEMCG_CACHE
] * PAGE_SIZE
);
5233 seq_printf(m
, "kernel_stack %llu\n",
5234 (u64
)stat
[MEMCG_KERNEL_STACK_KB
] * 1024);
5235 seq_printf(m
, "slab %llu\n",
5236 (u64
)(stat
[NR_SLAB_RECLAIMABLE
] +
5237 stat
[NR_SLAB_UNRECLAIMABLE
]) * PAGE_SIZE
);
5238 seq_printf(m
, "sock %llu\n",
5239 (u64
)stat
[MEMCG_SOCK
] * PAGE_SIZE
);
5241 seq_printf(m
, "shmem %llu\n",
5242 (u64
)stat
[NR_SHMEM
] * PAGE_SIZE
);
5243 seq_printf(m
, "file_mapped %llu\n",
5244 (u64
)stat
[NR_FILE_MAPPED
] * PAGE_SIZE
);
5245 seq_printf(m
, "file_dirty %llu\n",
5246 (u64
)stat
[NR_FILE_DIRTY
] * PAGE_SIZE
);
5247 seq_printf(m
, "file_writeback %llu\n",
5248 (u64
)stat
[NR_WRITEBACK
] * PAGE_SIZE
);
5250 for (i
= 0; i
< NR_LRU_LISTS
; i
++) {
5251 struct mem_cgroup
*mi
;
5252 unsigned long val
= 0;
5254 for_each_mem_cgroup_tree(mi
, memcg
)
5255 val
+= mem_cgroup_nr_lru_pages(mi
, BIT(i
));
5256 seq_printf(m
, "%s %llu\n",
5257 mem_cgroup_lru_names
[i
], (u64
)val
* PAGE_SIZE
);
5260 seq_printf(m
, "slab_reclaimable %llu\n",
5261 (u64
)stat
[NR_SLAB_RECLAIMABLE
] * PAGE_SIZE
);
5262 seq_printf(m
, "slab_unreclaimable %llu\n",
5263 (u64
)stat
[NR_SLAB_UNRECLAIMABLE
] * PAGE_SIZE
);
5265 /* Accumulated memory events */
5267 seq_printf(m
, "pgfault %lu\n", events
[PGFAULT
]);
5268 seq_printf(m
, "pgmajfault %lu\n", events
[PGMAJFAULT
]);
5270 seq_printf(m
, "pgrefill %lu\n", events
[PGREFILL
]);
5271 seq_printf(m
, "pgscan %lu\n", events
[PGSCAN_KSWAPD
] +
5272 events
[PGSCAN_DIRECT
]);
5273 seq_printf(m
, "pgsteal %lu\n", events
[PGSTEAL_KSWAPD
] +
5274 events
[PGSTEAL_DIRECT
]);
5275 seq_printf(m
, "pgactivate %lu\n", events
[PGACTIVATE
]);
5276 seq_printf(m
, "pgdeactivate %lu\n", events
[PGDEACTIVATE
]);
5277 seq_printf(m
, "pglazyfree %lu\n", events
[PGLAZYFREE
]);
5278 seq_printf(m
, "pglazyfreed %lu\n", events
[PGLAZYFREED
]);
5280 seq_printf(m
, "workingset_refault %lu\n",
5281 stat
[WORKINGSET_REFAULT
]);
5282 seq_printf(m
, "workingset_activate %lu\n",
5283 stat
[WORKINGSET_ACTIVATE
]);
5284 seq_printf(m
, "workingset_nodereclaim %lu\n",
5285 stat
[WORKINGSET_NODERECLAIM
]);
5290 static struct cftype memory_files
[] = {
5293 .flags
= CFTYPE_NOT_ON_ROOT
,
5294 .read_u64
= memory_current_read
,
5298 .flags
= CFTYPE_NOT_ON_ROOT
,
5299 .seq_show
= memory_low_show
,
5300 .write
= memory_low_write
,
5304 .flags
= CFTYPE_NOT_ON_ROOT
,
5305 .seq_show
= memory_high_show
,
5306 .write
= memory_high_write
,
5310 .flags
= CFTYPE_NOT_ON_ROOT
,
5311 .seq_show
= memory_max_show
,
5312 .write
= memory_max_write
,
5316 .flags
= CFTYPE_NOT_ON_ROOT
,
5317 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
5318 .seq_show
= memory_events_show
,
5322 .flags
= CFTYPE_NOT_ON_ROOT
,
5323 .seq_show
= memory_stat_show
,
5328 struct cgroup_subsys memory_cgrp_subsys
= {
5329 .css_alloc
= mem_cgroup_css_alloc
,
5330 .css_online
= mem_cgroup_css_online
,
5331 .css_offline
= mem_cgroup_css_offline
,
5332 .css_released
= mem_cgroup_css_released
,
5333 .css_free
= mem_cgroup_css_free
,
5334 .css_reset
= mem_cgroup_css_reset
,
5335 .can_attach
= mem_cgroup_can_attach
,
5336 .cancel_attach
= mem_cgroup_cancel_attach
,
5337 .post_attach
= mem_cgroup_move_task
,
5338 .bind
= mem_cgroup_bind
,
5339 .dfl_cftypes
= memory_files
,
5340 .legacy_cftypes
= mem_cgroup_legacy_files
,
5345 * mem_cgroup_low - check if memory consumption is below the normal range
5346 * @root: the top ancestor of the sub-tree being checked
5347 * @memcg: the memory cgroup to check
5349 * Returns %true if memory consumption of @memcg, and that of all
5350 * ancestors up to (but not including) @root, is below the normal range.
5352 * @root is exclusive; it is never low when looked at directly and isn't
5353 * checked when traversing the hierarchy.
5355 * Excluding @root enables using memory.low to prioritize memory usage
5356 * between cgroups within a subtree of the hierarchy that is limited by
5357 * memory.high or memory.max.
5359 * For example, given cgroup A with children B and C:
5367 * 1. A/memory.current > A/memory.high
5368 * 2. A/B/memory.current < A/B/memory.low
5369 * 3. A/C/memory.current >= A/C/memory.low
5371 * As 'A' is high, i.e. triggers reclaim from 'A', and 'B' is low, we
5372 * should reclaim from 'C' until 'A' is no longer high or until we can
5373 * no longer reclaim from 'C'. If 'A', i.e. @root, isn't excluded by
5374 * mem_cgroup_low when reclaming from 'A', then 'B' won't be considered
5375 * low and we will reclaim indiscriminately from both 'B' and 'C'.
5377 bool mem_cgroup_low(struct mem_cgroup
*root
, struct mem_cgroup
*memcg
)
5379 if (mem_cgroup_disabled())
5383 root
= root_mem_cgroup
;
5387 for (; memcg
!= root
; memcg
= parent_mem_cgroup(memcg
)) {
5388 if (page_counter_read(&memcg
->memory
) >= memcg
->low
)
5396 * mem_cgroup_try_charge - try charging a page
5397 * @page: page to charge
5398 * @mm: mm context of the victim
5399 * @gfp_mask: reclaim mode
5400 * @memcgp: charged memcg return
5401 * @compound: charge the page as compound or small page
5403 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5404 * pages according to @gfp_mask if necessary.
5406 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5407 * Otherwise, an error code is returned.
5409 * After page->mapping has been set up, the caller must finalize the
5410 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5411 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5413 int mem_cgroup_try_charge(struct page
*page
, struct mm_struct
*mm
,
5414 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
,
5417 struct mem_cgroup
*memcg
= NULL
;
5418 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5421 if (mem_cgroup_disabled())
5424 if (PageSwapCache(page
)) {
5426 * Every swap fault against a single page tries to charge the
5427 * page, bail as early as possible. shmem_unuse() encounters
5428 * already charged pages, too. The USED bit is protected by
5429 * the page lock, which serializes swap cache removal, which
5430 * in turn serializes uncharging.
5432 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
5433 if (compound_head(page
)->mem_cgroup
)
5436 if (do_swap_account
) {
5437 swp_entry_t ent
= { .val
= page_private(page
), };
5438 unsigned short id
= lookup_swap_cgroup_id(ent
);
5441 memcg
= mem_cgroup_from_id(id
);
5442 if (memcg
&& !css_tryget_online(&memcg
->css
))
5449 memcg
= get_mem_cgroup_from_mm(mm
);
5451 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
5453 css_put(&memcg
->css
);
5460 * mem_cgroup_commit_charge - commit a page charge
5461 * @page: page to charge
5462 * @memcg: memcg to charge the page to
5463 * @lrucare: page might be on LRU already
5464 * @compound: charge the page as compound or small page
5466 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5467 * after page->mapping has been set up. This must happen atomically
5468 * as part of the page instantiation, i.e. under the page table lock
5469 * for anonymous pages, under the page lock for page and swap cache.
5471 * In addition, the page must not be on the LRU during the commit, to
5472 * prevent racing with task migration. If it might be, use @lrucare.
5474 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5476 void mem_cgroup_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5477 bool lrucare
, bool compound
)
5479 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5481 VM_BUG_ON_PAGE(!page
->mapping
, page
);
5482 VM_BUG_ON_PAGE(PageLRU(page
) && !lrucare
, page
);
5484 if (mem_cgroup_disabled())
5487 * Swap faults will attempt to charge the same page multiple
5488 * times. But reuse_swap_page() might have removed the page
5489 * from swapcache already, so we can't check PageSwapCache().
5494 commit_charge(page
, memcg
, lrucare
);
5496 local_irq_disable();
5497 mem_cgroup_charge_statistics(memcg
, page
, compound
, nr_pages
);
5498 memcg_check_events(memcg
, page
);
5501 if (do_memsw_account() && PageSwapCache(page
)) {
5502 swp_entry_t entry
= { .val
= page_private(page
) };
5504 * The swap entry might not get freed for a long time,
5505 * let's not wait for it. The page already received a
5506 * memory+swap charge, drop the swap entry duplicate.
5508 mem_cgroup_uncharge_swap(entry
, nr_pages
);
5513 * mem_cgroup_cancel_charge - cancel a page charge
5514 * @page: page to charge
5515 * @memcg: memcg to charge the page to
5516 * @compound: charge the page as compound or small page
5518 * Cancel a charge transaction started by mem_cgroup_try_charge().
5520 void mem_cgroup_cancel_charge(struct page
*page
, struct mem_cgroup
*memcg
,
5523 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5525 if (mem_cgroup_disabled())
5528 * Swap faults will attempt to charge the same page multiple
5529 * times. But reuse_swap_page() might have removed the page
5530 * from swapcache already, so we can't check PageSwapCache().
5535 cancel_charge(memcg
, nr_pages
);
5538 static void uncharge_batch(struct mem_cgroup
*memcg
, unsigned long pgpgout
,
5539 unsigned long nr_anon
, unsigned long nr_file
,
5540 unsigned long nr_kmem
, unsigned long nr_huge
,
5541 unsigned long nr_shmem
, struct page
*dummy_page
)
5543 unsigned long nr_pages
= nr_anon
+ nr_file
+ nr_kmem
;
5544 unsigned long flags
;
5546 if (!mem_cgroup_is_root(memcg
)) {
5547 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5548 if (do_memsw_account())
5549 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
5550 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && nr_kmem
)
5551 page_counter_uncharge(&memcg
->kmem
, nr_kmem
);
5552 memcg_oom_recover(memcg
);
5555 local_irq_save(flags
);
5556 __this_cpu_sub(memcg
->stat
->count
[MEMCG_RSS
], nr_anon
);
5557 __this_cpu_sub(memcg
->stat
->count
[MEMCG_CACHE
], nr_file
);
5558 __this_cpu_sub(memcg
->stat
->count
[MEMCG_RSS_HUGE
], nr_huge
);
5559 __this_cpu_sub(memcg
->stat
->count
[NR_SHMEM
], nr_shmem
);
5560 __this_cpu_add(memcg
->stat
->events
[PGPGOUT
], pgpgout
);
5561 __this_cpu_add(memcg
->stat
->nr_page_events
, nr_pages
);
5562 memcg_check_events(memcg
, dummy_page
);
5563 local_irq_restore(flags
);
5565 if (!mem_cgroup_is_root(memcg
))
5566 css_put_many(&memcg
->css
, nr_pages
);
5569 static void uncharge_list(struct list_head
*page_list
)
5571 struct mem_cgroup
*memcg
= NULL
;
5572 unsigned long nr_shmem
= 0;
5573 unsigned long nr_anon
= 0;
5574 unsigned long nr_file
= 0;
5575 unsigned long nr_huge
= 0;
5576 unsigned long nr_kmem
= 0;
5577 unsigned long pgpgout
= 0;
5578 struct list_head
*next
;
5582 * Note that the list can be a single page->lru; hence the
5583 * do-while loop instead of a simple list_for_each_entry().
5585 next
= page_list
->next
;
5587 page
= list_entry(next
, struct page
, lru
);
5588 next
= page
->lru
.next
;
5590 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5591 VM_BUG_ON_PAGE(!PageHWPoison(page
) && page_count(page
), page
);
5593 if (!page
->mem_cgroup
)
5597 * Nobody should be changing or seriously looking at
5598 * page->mem_cgroup at this point, we have fully
5599 * exclusive access to the page.
5602 if (memcg
!= page
->mem_cgroup
) {
5604 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5605 nr_kmem
, nr_huge
, nr_shmem
, page
);
5606 pgpgout
= nr_anon
= nr_file
= nr_kmem
= 0;
5607 nr_huge
= nr_shmem
= 0;
5609 memcg
= page
->mem_cgroup
;
5612 if (!PageKmemcg(page
)) {
5613 unsigned int nr_pages
= 1;
5615 if (PageTransHuge(page
)) {
5616 nr_pages
<<= compound_order(page
);
5617 nr_huge
+= nr_pages
;
5620 nr_anon
+= nr_pages
;
5622 nr_file
+= nr_pages
;
5623 if (PageSwapBacked(page
))
5624 nr_shmem
+= nr_pages
;
5628 nr_kmem
+= 1 << compound_order(page
);
5629 __ClearPageKmemcg(page
);
5632 page
->mem_cgroup
= NULL
;
5633 } while (next
!= page_list
);
5636 uncharge_batch(memcg
, pgpgout
, nr_anon
, nr_file
,
5637 nr_kmem
, nr_huge
, nr_shmem
, page
);
5641 * mem_cgroup_uncharge - uncharge a page
5642 * @page: page to uncharge
5644 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5645 * mem_cgroup_commit_charge().
5647 void mem_cgroup_uncharge(struct page
*page
)
5649 if (mem_cgroup_disabled())
5652 /* Don't touch page->lru of any random page, pre-check: */
5653 if (!page
->mem_cgroup
)
5656 INIT_LIST_HEAD(&page
->lru
);
5657 uncharge_list(&page
->lru
);
5661 * mem_cgroup_uncharge_list - uncharge a list of page
5662 * @page_list: list of pages to uncharge
5664 * Uncharge a list of pages previously charged with
5665 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5667 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
5669 if (mem_cgroup_disabled())
5672 if (!list_empty(page_list
))
5673 uncharge_list(page_list
);
5677 * mem_cgroup_migrate - charge a page's replacement
5678 * @oldpage: currently circulating page
5679 * @newpage: replacement page
5681 * Charge @newpage as a replacement page for @oldpage. @oldpage will
5682 * be uncharged upon free.
5684 * Both pages must be locked, @newpage->mapping must be set up.
5686 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
5688 struct mem_cgroup
*memcg
;
5689 unsigned int nr_pages
;
5691 unsigned long flags
;
5693 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
5694 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
5695 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
5696 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
5699 if (mem_cgroup_disabled())
5702 /* Page cache replacement: new page already charged? */
5703 if (newpage
->mem_cgroup
)
5706 /* Swapcache readahead pages can get replaced before being charged */
5707 memcg
= oldpage
->mem_cgroup
;
5711 /* Force-charge the new page. The old one will be freed soon */
5712 compound
= PageTransHuge(newpage
);
5713 nr_pages
= compound
? hpage_nr_pages(newpage
) : 1;
5715 page_counter_charge(&memcg
->memory
, nr_pages
);
5716 if (do_memsw_account())
5717 page_counter_charge(&memcg
->memsw
, nr_pages
);
5718 css_get_many(&memcg
->css
, nr_pages
);
5720 commit_charge(newpage
, memcg
, false);
5722 local_irq_save(flags
);
5723 mem_cgroup_charge_statistics(memcg
, newpage
, compound
, nr_pages
);
5724 memcg_check_events(memcg
, newpage
);
5725 local_irq_restore(flags
);
5728 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
5729 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
5731 void mem_cgroup_sk_alloc(struct sock
*sk
)
5733 struct mem_cgroup
*memcg
;
5735 if (!mem_cgroup_sockets_enabled
)
5739 * Socket cloning can throw us here with sk_memcg already
5740 * filled. It won't however, necessarily happen from
5741 * process context. So the test for root memcg given
5742 * the current task's memcg won't help us in this case.
5744 * Respecting the original socket's memcg is a better
5745 * decision in this case.
5748 BUG_ON(mem_cgroup_is_root(sk
->sk_memcg
));
5749 css_get(&sk
->sk_memcg
->css
);
5754 memcg
= mem_cgroup_from_task(current
);
5755 if (memcg
== root_mem_cgroup
)
5757 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
5759 if (css_tryget_online(&memcg
->css
))
5760 sk
->sk_memcg
= memcg
;
5765 void mem_cgroup_sk_free(struct sock
*sk
)
5768 css_put(&sk
->sk_memcg
->css
);
5772 * mem_cgroup_charge_skmem - charge socket memory
5773 * @memcg: memcg to charge
5774 * @nr_pages: number of pages to charge
5776 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
5777 * @memcg's configured limit, %false if the charge had to be forced.
5779 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5781 gfp_t gfp_mask
= GFP_KERNEL
;
5783 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5784 struct page_counter
*fail
;
5786 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
5787 memcg
->tcpmem_pressure
= 0;
5790 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
5791 memcg
->tcpmem_pressure
= 1;
5795 /* Don't block in the packet receive path */
5797 gfp_mask
= GFP_NOWAIT
;
5799 this_cpu_add(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5801 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
5804 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
5809 * mem_cgroup_uncharge_skmem - uncharge socket memory
5810 * @memcg - memcg to uncharge
5811 * @nr_pages - number of pages to uncharge
5813 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
5815 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
5816 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
5820 this_cpu_sub(memcg
->stat
->count
[MEMCG_SOCK
], nr_pages
);
5822 page_counter_uncharge(&memcg
->memory
, nr_pages
);
5823 css_put_many(&memcg
->css
, nr_pages
);
5826 static int __init
cgroup_memory(char *s
)
5830 while ((token
= strsep(&s
, ",")) != NULL
) {
5833 if (!strcmp(token
, "nosocket"))
5834 cgroup_memory_nosocket
= true;
5835 if (!strcmp(token
, "nokmem"))
5836 cgroup_memory_nokmem
= true;
5840 __setup("cgroup.memory=", cgroup_memory
);
5843 * subsys_initcall() for memory controller.
5845 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
5846 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
5847 * basically everything that doesn't depend on a specific mem_cgroup structure
5848 * should be initialized from here.
5850 static int __init
mem_cgroup_init(void)
5856 * Kmem cache creation is mostly done with the slab_mutex held,
5857 * so use a workqueue with limited concurrency to avoid stalling
5858 * all worker threads in case lots of cgroups are created and
5859 * destroyed simultaneously.
5861 memcg_kmem_cache_wq
= alloc_workqueue("memcg_kmem_cache", 0, 1);
5862 BUG_ON(!memcg_kmem_cache_wq
);
5865 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
5866 memcg_hotplug_cpu_dead
);
5868 for_each_possible_cpu(cpu
)
5869 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
5872 for_each_node(node
) {
5873 struct mem_cgroup_tree_per_node
*rtpn
;
5875 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
5876 node_online(node
) ? node
: NUMA_NO_NODE
);
5878 rtpn
->rb_root
= RB_ROOT
;
5879 spin_lock_init(&rtpn
->lock
);
5880 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
5885 subsys_initcall(mem_cgroup_init
);
5887 #ifdef CONFIG_MEMCG_SWAP
5888 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
5890 while (!atomic_inc_not_zero(&memcg
->id
.ref
)) {
5892 * The root cgroup cannot be destroyed, so it's refcount must
5895 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
5899 memcg
= parent_mem_cgroup(memcg
);
5901 memcg
= root_mem_cgroup
;
5907 * mem_cgroup_swapout - transfer a memsw charge to swap
5908 * @page: page whose memsw charge to transfer
5909 * @entry: swap entry to move the charge to
5911 * Transfer the memsw charge of @page to @entry.
5913 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
5915 struct mem_cgroup
*memcg
, *swap_memcg
;
5916 unsigned int nr_entries
;
5917 unsigned short oldid
;
5919 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5920 VM_BUG_ON_PAGE(page_count(page
), page
);
5922 if (!do_memsw_account())
5925 memcg
= page
->mem_cgroup
;
5927 /* Readahead page, never charged */
5932 * In case the memcg owning these pages has been offlined and doesn't
5933 * have an ID allocated to it anymore, charge the closest online
5934 * ancestor for the swap instead and transfer the memory+swap charge.
5936 swap_memcg
= mem_cgroup_id_get_online(memcg
);
5937 nr_entries
= hpage_nr_pages(page
);
5938 /* Get references for the tail pages, too */
5940 mem_cgroup_id_get_many(swap_memcg
, nr_entries
- 1);
5941 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
),
5943 VM_BUG_ON_PAGE(oldid
, page
);
5944 mem_cgroup_swap_statistics(swap_memcg
, nr_entries
);
5946 page
->mem_cgroup
= NULL
;
5948 if (!mem_cgroup_is_root(memcg
))
5949 page_counter_uncharge(&memcg
->memory
, nr_entries
);
5951 if (memcg
!= swap_memcg
) {
5952 if (!mem_cgroup_is_root(swap_memcg
))
5953 page_counter_charge(&swap_memcg
->memsw
, nr_entries
);
5954 page_counter_uncharge(&memcg
->memsw
, nr_entries
);
5958 * Interrupts should be disabled here because the caller holds the
5959 * mapping->tree_lock lock which is taken with interrupts-off. It is
5960 * important here to have the interrupts disabled because it is the
5961 * only synchronisation we have for udpating the per-CPU variables.
5963 VM_BUG_ON(!irqs_disabled());
5964 mem_cgroup_charge_statistics(memcg
, page
, PageTransHuge(page
),
5966 memcg_check_events(memcg
, page
);
5968 if (!mem_cgroup_is_root(memcg
))
5969 css_put(&memcg
->css
);
5973 * mem_cgroup_try_charge_swap - try charging swap space for a page
5974 * @page: page being added to swap
5975 * @entry: swap entry to charge
5977 * Try to charge @page's memcg for the swap space at @entry.
5979 * Returns 0 on success, -ENOMEM on failure.
5981 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
5983 unsigned int nr_pages
= hpage_nr_pages(page
);
5984 struct page_counter
*counter
;
5985 struct mem_cgroup
*memcg
;
5986 unsigned short oldid
;
5988 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) || !do_swap_account
)
5991 memcg
= page
->mem_cgroup
;
5993 /* Readahead page, never charged */
5997 memcg
= mem_cgroup_id_get_online(memcg
);
5999 if (!mem_cgroup_is_root(memcg
) &&
6000 !page_counter_try_charge(&memcg
->swap
, nr_pages
, &counter
)) {
6001 mem_cgroup_id_put(memcg
);
6005 /* Get references for the tail pages, too */
6007 mem_cgroup_id_get_many(memcg
, nr_pages
- 1);
6008 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
), nr_pages
);
6009 VM_BUG_ON_PAGE(oldid
, page
);
6010 mem_cgroup_swap_statistics(memcg
, nr_pages
);
6016 * mem_cgroup_uncharge_swap - uncharge swap space
6017 * @entry: swap entry to uncharge
6018 * @nr_pages: the amount of swap space to uncharge
6020 void mem_cgroup_uncharge_swap(swp_entry_t entry
, unsigned int nr_pages
)
6022 struct mem_cgroup
*memcg
;
6025 if (!do_swap_account
)
6028 id
= swap_cgroup_record(entry
, 0, nr_pages
);
6030 memcg
= mem_cgroup_from_id(id
);
6032 if (!mem_cgroup_is_root(memcg
)) {
6033 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
6034 page_counter_uncharge(&memcg
->swap
, nr_pages
);
6036 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
6038 mem_cgroup_swap_statistics(memcg
, -nr_pages
);
6039 mem_cgroup_id_put_many(memcg
, nr_pages
);
6044 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
6046 long nr_swap_pages
= get_nr_swap_pages();
6048 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
6049 return nr_swap_pages
;
6050 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
6051 nr_swap_pages
= min_t(long, nr_swap_pages
,
6052 READ_ONCE(memcg
->swap
.limit
) -
6053 page_counter_read(&memcg
->swap
));
6054 return nr_swap_pages
;
6057 bool mem_cgroup_swap_full(struct page
*page
)
6059 struct mem_cgroup
*memcg
;
6061 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
6065 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
6068 memcg
= page
->mem_cgroup
;
6072 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
6073 if (page_counter_read(&memcg
->swap
) * 2 >= memcg
->swap
.limit
)
6079 /* for remember boot option*/
6080 #ifdef CONFIG_MEMCG_SWAP_ENABLED
6081 static int really_do_swap_account __initdata
= 1;
6083 static int really_do_swap_account __initdata
;
6086 static int __init
enable_swap_account(char *s
)
6088 if (!strcmp(s
, "1"))
6089 really_do_swap_account
= 1;
6090 else if (!strcmp(s
, "0"))
6091 really_do_swap_account
= 0;
6094 __setup("swapaccount=", enable_swap_account
);
6096 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
6099 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6101 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
6104 static int swap_max_show(struct seq_file
*m
, void *v
)
6106 struct mem_cgroup
*memcg
= mem_cgroup_from_css(seq_css(m
));
6107 unsigned long max
= READ_ONCE(memcg
->swap
.limit
);
6109 if (max
== PAGE_COUNTER_MAX
)
6110 seq_puts(m
, "max\n");
6112 seq_printf(m
, "%llu\n", (u64
)max
* PAGE_SIZE
);
6117 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
6118 char *buf
, size_t nbytes
, loff_t off
)
6120 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6124 buf
= strstrip(buf
);
6125 err
= page_counter_memparse(buf
, "max", &max
);
6129 mutex_lock(&memcg_limit_mutex
);
6130 err
= page_counter_limit(&memcg
->swap
, max
);
6131 mutex_unlock(&memcg_limit_mutex
);
6138 static struct cftype swap_files
[] = {
6140 .name
= "swap.current",
6141 .flags
= CFTYPE_NOT_ON_ROOT
,
6142 .read_u64
= swap_current_read
,
6146 .flags
= CFTYPE_NOT_ON_ROOT
,
6147 .seq_show
= swap_max_show
,
6148 .write
= swap_max_write
,
6153 static struct cftype memsw_cgroup_files
[] = {
6155 .name
= "memsw.usage_in_bytes",
6156 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
6157 .read_u64
= mem_cgroup_read_u64
,
6160 .name
= "memsw.max_usage_in_bytes",
6161 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
6162 .write
= mem_cgroup_reset
,
6163 .read_u64
= mem_cgroup_read_u64
,
6166 .name
= "memsw.limit_in_bytes",
6167 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
6168 .write
= mem_cgroup_write
,
6169 .read_u64
= mem_cgroup_read_u64
,
6172 .name
= "memsw.failcnt",
6173 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
6174 .write
= mem_cgroup_reset
,
6175 .read_u64
= mem_cgroup_read_u64
,
6177 { }, /* terminate */
6180 static int __init
mem_cgroup_swap_init(void)
6182 if (!mem_cgroup_disabled() && really_do_swap_account
) {
6183 do_swap_account
= 1;
6184 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
,
6186 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
,
6187 memsw_cgroup_files
));
6191 subsys_initcall(mem_cgroup_swap_init
);
6193 #endif /* CONFIG_MEMCG_SWAP */