1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* memcontrol.c - Memory Controller
4 * Copyright IBM Corporation, 2007
5 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
7 * Copyright 2007 OpenVZ SWsoft Inc
8 * Author: Pavel Emelianov <xemul@openvz.org>
11 * Copyright (C) 2009 Nokia Corporation
12 * Author: Kirill A. Shutemov
14 * Kernel Memory Controller
15 * Copyright (C) 2012 Parallels Inc. and Google Inc.
16 * Authors: Glauber Costa and Suleiman Souhlal
19 * Charge lifetime sanitation
20 * Lockless page tracking & accounting
21 * Unified hierarchy configuration model
22 * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
25 #include <linux/page_counter.h>
26 #include <linux/memcontrol.h>
27 #include <linux/cgroup.h>
28 #include <linux/pagewalk.h>
29 #include <linux/sched/mm.h>
30 #include <linux/shmem_fs.h>
31 #include <linux/hugetlb.h>
32 #include <linux/pagemap.h>
33 #include <linux/vm_event_item.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/swap_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
59 #include <linux/tracehook.h>
60 #include <linux/psi.h>
61 #include <linux/seq_buf.h>
67 #include <linux/uaccess.h>
69 #include <trace/events/vmscan.h>
71 struct cgroup_subsys memory_cgrp_subsys __read_mostly
;
72 EXPORT_SYMBOL(memory_cgrp_subsys
);
74 struct mem_cgroup
*root_mem_cgroup __read_mostly
;
76 #define MEM_CGROUP_RECLAIM_RETRIES 5
78 /* Socket memory accounting disabled? */
79 static bool cgroup_memory_nosocket
;
81 /* Kernel memory accounting disabled? */
82 static bool cgroup_memory_nokmem
;
84 /* Whether the swap controller is active */
85 #ifdef CONFIG_MEMCG_SWAP
86 int do_swap_account __read_mostly
;
88 #define do_swap_account 0
91 #ifdef CONFIG_CGROUP_WRITEBACK
92 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq
);
95 /* Whether legacy memory+swap accounting is active */
96 static bool do_memsw_account(void)
98 return !cgroup_subsys_on_dfl(memory_cgrp_subsys
) && do_swap_account
;
101 static const char *const mem_cgroup_lru_names
[] = {
109 #define THRESHOLDS_EVENTS_TARGET 128
110 #define SOFTLIMIT_EVENTS_TARGET 1024
111 #define NUMAINFO_EVENTS_TARGET 1024
114 * Cgroups above their limits are maintained in a RB-Tree, independent of
115 * their hierarchy representation
118 struct mem_cgroup_tree_per_node
{
119 struct rb_root rb_root
;
120 struct rb_node
*rb_rightmost
;
124 struct mem_cgroup_tree
{
125 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
128 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
131 struct mem_cgroup_eventfd_list
{
132 struct list_head list
;
133 struct eventfd_ctx
*eventfd
;
137 * cgroup_event represents events which userspace want to receive.
139 struct mem_cgroup_event
{
141 * memcg which the event belongs to.
143 struct mem_cgroup
*memcg
;
145 * eventfd to signal userspace about the event.
147 struct eventfd_ctx
*eventfd
;
149 * Each of these stored in a list by the cgroup.
151 struct list_head list
;
153 * register_event() callback will be used to add new userspace
154 * waiter for changes related to this event. Use eventfd_signal()
155 * on eventfd to send notification to userspace.
157 int (*register_event
)(struct mem_cgroup
*memcg
,
158 struct eventfd_ctx
*eventfd
, const char *args
);
160 * unregister_event() callback will be called when userspace closes
161 * the eventfd or on cgroup removing. This callback must be set,
162 * if you want provide notification functionality.
164 void (*unregister_event
)(struct mem_cgroup
*memcg
,
165 struct eventfd_ctx
*eventfd
);
167 * All fields below needed to unregister event when
168 * userspace closes eventfd.
171 wait_queue_head_t
*wqh
;
172 wait_queue_entry_t wait
;
173 struct work_struct remove
;
176 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
177 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
179 /* Stuffs for move charges at task migration. */
181 * Types of charges to be moved.
183 #define MOVE_ANON 0x1U
184 #define MOVE_FILE 0x2U
185 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
187 /* "mc" and its members are protected by cgroup_mutex */
188 static struct move_charge_struct
{
189 spinlock_t lock
; /* for from, to */
190 struct mm_struct
*mm
;
191 struct mem_cgroup
*from
;
192 struct mem_cgroup
*to
;
194 unsigned long precharge
;
195 unsigned long moved_charge
;
196 unsigned long moved_swap
;
197 struct task_struct
*moving_task
; /* a task moving charges */
198 wait_queue_head_t waitq
; /* a waitq for other context */
200 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
201 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
205 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
206 * limit reclaim to prevent infinite loops, if they ever occur.
208 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
209 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
212 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
213 MEM_CGROUP_CHARGE_TYPE_ANON
,
214 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
215 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
219 /* for encoding cft->private value on file */
228 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
229 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
230 #define MEMFILE_ATTR(val) ((val) & 0xffff)
231 /* Used for OOM nofiier */
232 #define OOM_CONTROL (0)
235 * Iteration constructs for visiting all cgroups (under a tree). If
236 * loops are exited prematurely (break), mem_cgroup_iter_break() must
237 * be used for reference counting.
239 #define for_each_mem_cgroup_tree(iter, root) \
240 for (iter = mem_cgroup_iter(root, NULL, NULL); \
242 iter = mem_cgroup_iter(root, iter, NULL))
244 #define for_each_mem_cgroup(iter) \
245 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
247 iter = mem_cgroup_iter(NULL, iter, NULL))
249 static inline bool should_force_charge(void)
251 return tsk_is_oom_victim(current
) || fatal_signal_pending(current
) ||
252 (current
->flags
& PF_EXITING
);
255 /* Some nice accessors for the vmpressure. */
256 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
259 memcg
= root_mem_cgroup
;
260 return &memcg
->vmpressure
;
263 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
265 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
268 #ifdef CONFIG_MEMCG_KMEM
270 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
271 * The main reason for not using cgroup id for this:
272 * this works better in sparse environments, where we have a lot of memcgs,
273 * but only a few kmem-limited. Or also, if we have, for instance, 200
274 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
275 * 200 entry array for that.
277 * The current size of the caches array is stored in memcg_nr_cache_ids. It
278 * will double each time we have to increase it.
280 static DEFINE_IDA(memcg_cache_ida
);
281 int memcg_nr_cache_ids
;
283 /* Protects memcg_nr_cache_ids */
284 static DECLARE_RWSEM(memcg_cache_ids_sem
);
286 void memcg_get_cache_ids(void)
288 down_read(&memcg_cache_ids_sem
);
291 void memcg_put_cache_ids(void)
293 up_read(&memcg_cache_ids_sem
);
297 * MIN_SIZE is different than 1, because we would like to avoid going through
298 * the alloc/free process all the time. In a small machine, 4 kmem-limited
299 * cgroups is a reasonable guess. In the future, it could be a parameter or
300 * tunable, but that is strictly not necessary.
302 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
303 * this constant directly from cgroup, but it is understandable that this is
304 * better kept as an internal representation in cgroup.c. In any case, the
305 * cgrp_id space is not getting any smaller, and we don't have to necessarily
306 * increase ours as well if it increases.
308 #define MEMCG_CACHES_MIN_SIZE 4
309 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
312 * A lot of the calls to the cache allocation functions are expected to be
313 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
314 * conditional to this static branch, we'll have to allow modules that does
315 * kmem_cache_alloc and the such to see this symbol as well
317 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
318 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
320 struct workqueue_struct
*memcg_kmem_cache_wq
;
322 static int memcg_shrinker_map_size
;
323 static DEFINE_MUTEX(memcg_shrinker_map_mutex
);
325 static void memcg_free_shrinker_map_rcu(struct rcu_head
*head
)
327 kvfree(container_of(head
, struct memcg_shrinker_map
, rcu
));
330 static int memcg_expand_one_shrinker_map(struct mem_cgroup
*memcg
,
331 int size
, int old_size
)
333 struct memcg_shrinker_map
*new, *old
;
336 lockdep_assert_held(&memcg_shrinker_map_mutex
);
339 old
= rcu_dereference_protected(
340 mem_cgroup_nodeinfo(memcg
, nid
)->shrinker_map
, true);
341 /* Not yet online memcg */
345 new = kvmalloc(sizeof(*new) + size
, GFP_KERNEL
);
349 /* Set all old bits, clear all new bits */
350 memset(new->map
, (int)0xff, old_size
);
351 memset((void *)new->map
+ old_size
, 0, size
- old_size
);
353 rcu_assign_pointer(memcg
->nodeinfo
[nid
]->shrinker_map
, new);
354 call_rcu(&old
->rcu
, memcg_free_shrinker_map_rcu
);
360 static void memcg_free_shrinker_maps(struct mem_cgroup
*memcg
)
362 struct mem_cgroup_per_node
*pn
;
363 struct memcg_shrinker_map
*map
;
366 if (mem_cgroup_is_root(memcg
))
370 pn
= mem_cgroup_nodeinfo(memcg
, nid
);
371 map
= rcu_dereference_protected(pn
->shrinker_map
, true);
374 rcu_assign_pointer(pn
->shrinker_map
, NULL
);
378 static int memcg_alloc_shrinker_maps(struct mem_cgroup
*memcg
)
380 struct memcg_shrinker_map
*map
;
381 int nid
, size
, ret
= 0;
383 if (mem_cgroup_is_root(memcg
))
386 mutex_lock(&memcg_shrinker_map_mutex
);
387 size
= memcg_shrinker_map_size
;
389 map
= kvzalloc(sizeof(*map
) + size
, GFP_KERNEL
);
391 memcg_free_shrinker_maps(memcg
);
395 rcu_assign_pointer(memcg
->nodeinfo
[nid
]->shrinker_map
, map
);
397 mutex_unlock(&memcg_shrinker_map_mutex
);
402 int memcg_expand_shrinker_maps(int new_id
)
404 int size
, old_size
, ret
= 0;
405 struct mem_cgroup
*memcg
;
407 size
= DIV_ROUND_UP(new_id
+ 1, BITS_PER_LONG
) * sizeof(unsigned long);
408 old_size
= memcg_shrinker_map_size
;
409 if (size
<= old_size
)
412 mutex_lock(&memcg_shrinker_map_mutex
);
413 if (!root_mem_cgroup
)
416 for_each_mem_cgroup(memcg
) {
417 if (mem_cgroup_is_root(memcg
))
419 ret
= memcg_expand_one_shrinker_map(memcg
, size
, old_size
);
425 memcg_shrinker_map_size
= size
;
426 mutex_unlock(&memcg_shrinker_map_mutex
);
430 void memcg_set_shrinker_bit(struct mem_cgroup
*memcg
, int nid
, int shrinker_id
)
432 if (shrinker_id
>= 0 && memcg
&& !mem_cgroup_is_root(memcg
)) {
433 struct memcg_shrinker_map
*map
;
436 map
= rcu_dereference(memcg
->nodeinfo
[nid
]->shrinker_map
);
437 /* Pairs with smp mb in shrink_slab() */
438 smp_mb__before_atomic();
439 set_bit(shrinker_id
, map
->map
);
444 #else /* CONFIG_MEMCG_KMEM */
445 static int memcg_alloc_shrinker_maps(struct mem_cgroup
*memcg
)
449 static void memcg_free_shrinker_maps(struct mem_cgroup
*memcg
) { }
450 #endif /* CONFIG_MEMCG_KMEM */
453 * mem_cgroup_css_from_page - css of the memcg associated with a page
454 * @page: page of interest
456 * If memcg is bound to the default hierarchy, css of the memcg associated
457 * with @page is returned. The returned css remains associated with @page
458 * until it is released.
460 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
463 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
465 struct mem_cgroup
*memcg
;
467 memcg
= page
->mem_cgroup
;
469 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
470 memcg
= root_mem_cgroup
;
476 * page_cgroup_ino - return inode number of the memcg a page is charged to
479 * Look up the closest online ancestor of the memory cgroup @page is charged to
480 * and return its inode number or 0 if @page is not charged to any cgroup. It
481 * is safe to call this function without holding a reference to @page.
483 * Note, this function is inherently racy, because there is nothing to prevent
484 * the cgroup inode from getting torn down and potentially reallocated a moment
485 * after page_cgroup_ino() returns, so it only should be used by callers that
486 * do not care (such as procfs interfaces).
488 ino_t
page_cgroup_ino(struct page
*page
)
490 struct mem_cgroup
*memcg
;
491 unsigned long ino
= 0;
494 if (PageHead(page
) && PageSlab(page
))
495 memcg
= memcg_from_slab_page(page
);
497 memcg
= READ_ONCE(page
->mem_cgroup
);
498 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
499 memcg
= parent_mem_cgroup(memcg
);
501 ino
= cgroup_ino(memcg
->css
.cgroup
);
506 static struct mem_cgroup_per_node
*
507 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
509 int nid
= page_to_nid(page
);
511 return memcg
->nodeinfo
[nid
];
514 static struct mem_cgroup_tree_per_node
*
515 soft_limit_tree_node(int nid
)
517 return soft_limit_tree
.rb_tree_per_node
[nid
];
520 static struct mem_cgroup_tree_per_node
*
521 soft_limit_tree_from_page(struct page
*page
)
523 int nid
= page_to_nid(page
);
525 return soft_limit_tree
.rb_tree_per_node
[nid
];
528 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
529 struct mem_cgroup_tree_per_node
*mctz
,
530 unsigned long new_usage_in_excess
)
532 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
533 struct rb_node
*parent
= NULL
;
534 struct mem_cgroup_per_node
*mz_node
;
535 bool rightmost
= true;
540 mz
->usage_in_excess
= new_usage_in_excess
;
541 if (!mz
->usage_in_excess
)
545 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
547 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
) {
553 * We can't avoid mem cgroups that are over their soft
554 * limit by the same amount
556 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
561 mctz
->rb_rightmost
= &mz
->tree_node
;
563 rb_link_node(&mz
->tree_node
, parent
, p
);
564 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
568 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
569 struct mem_cgroup_tree_per_node
*mctz
)
574 if (&mz
->tree_node
== mctz
->rb_rightmost
)
575 mctz
->rb_rightmost
= rb_prev(&mz
->tree_node
);
577 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
581 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
582 struct mem_cgroup_tree_per_node
*mctz
)
586 spin_lock_irqsave(&mctz
->lock
, flags
);
587 __mem_cgroup_remove_exceeded(mz
, mctz
);
588 spin_unlock_irqrestore(&mctz
->lock
, flags
);
591 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
593 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
594 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
595 unsigned long excess
= 0;
597 if (nr_pages
> soft_limit
)
598 excess
= nr_pages
- soft_limit
;
603 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
605 unsigned long excess
;
606 struct mem_cgroup_per_node
*mz
;
607 struct mem_cgroup_tree_per_node
*mctz
;
609 mctz
= soft_limit_tree_from_page(page
);
613 * Necessary to update all ancestors when hierarchy is used.
614 * because their event counter is not touched.
616 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
617 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
618 excess
= soft_limit_excess(memcg
);
620 * We have to update the tree if mz is on RB-tree or
621 * mem is over its softlimit.
623 if (excess
|| mz
->on_tree
) {
626 spin_lock_irqsave(&mctz
->lock
, flags
);
627 /* if on-tree, remove it */
629 __mem_cgroup_remove_exceeded(mz
, mctz
);
631 * Insert again. mz->usage_in_excess will be updated.
632 * If excess is 0, no tree ops.
634 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
635 spin_unlock_irqrestore(&mctz
->lock
, flags
);
640 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
642 struct mem_cgroup_tree_per_node
*mctz
;
643 struct mem_cgroup_per_node
*mz
;
647 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
648 mctz
= soft_limit_tree_node(nid
);
650 mem_cgroup_remove_exceeded(mz
, mctz
);
654 static struct mem_cgroup_per_node
*
655 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
657 struct mem_cgroup_per_node
*mz
;
661 if (!mctz
->rb_rightmost
)
662 goto done
; /* Nothing to reclaim from */
664 mz
= rb_entry(mctz
->rb_rightmost
,
665 struct mem_cgroup_per_node
, tree_node
);
667 * Remove the node now but someone else can add it back,
668 * we will to add it back at the end of reclaim to its correct
669 * position in the tree.
671 __mem_cgroup_remove_exceeded(mz
, mctz
);
672 if (!soft_limit_excess(mz
->memcg
) ||
673 !css_tryget_online(&mz
->memcg
->css
))
679 static struct mem_cgroup_per_node
*
680 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
682 struct mem_cgroup_per_node
*mz
;
684 spin_lock_irq(&mctz
->lock
);
685 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
686 spin_unlock_irq(&mctz
->lock
);
691 * __mod_memcg_state - update cgroup memory statistics
692 * @memcg: the memory cgroup
693 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
694 * @val: delta to add to the counter, can be negative
696 void __mod_memcg_state(struct mem_cgroup
*memcg
, int idx
, int val
)
700 if (mem_cgroup_disabled())
703 x
= val
+ __this_cpu_read(memcg
->vmstats_percpu
->stat
[idx
]);
704 if (unlikely(abs(x
) > MEMCG_CHARGE_BATCH
)) {
705 struct mem_cgroup
*mi
;
708 * Batch local counters to keep them in sync with
709 * the hierarchical ones.
711 __this_cpu_add(memcg
->vmstats_local
->stat
[idx
], x
);
712 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
713 atomic_long_add(x
, &mi
->vmstats
[idx
]);
716 __this_cpu_write(memcg
->vmstats_percpu
->stat
[idx
], x
);
719 static struct mem_cgroup_per_node
*
720 parent_nodeinfo(struct mem_cgroup_per_node
*pn
, int nid
)
722 struct mem_cgroup
*parent
;
724 parent
= parent_mem_cgroup(pn
->memcg
);
727 return mem_cgroup_nodeinfo(parent
, nid
);
731 * __mod_lruvec_state - update lruvec memory statistics
732 * @lruvec: the lruvec
733 * @idx: the stat item
734 * @val: delta to add to the counter, can be negative
736 * The lruvec is the intersection of the NUMA node and a cgroup. This
737 * function updates the all three counters that are affected by a
738 * change of state at this level: per-node, per-cgroup, per-lruvec.
740 void __mod_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
743 pg_data_t
*pgdat
= lruvec_pgdat(lruvec
);
744 struct mem_cgroup_per_node
*pn
;
745 struct mem_cgroup
*memcg
;
749 __mod_node_page_state(pgdat
, idx
, val
);
751 if (mem_cgroup_disabled())
754 pn
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
758 __mod_memcg_state(memcg
, idx
, val
);
761 __this_cpu_add(pn
->lruvec_stat_local
->count
[idx
], val
);
763 x
= val
+ __this_cpu_read(pn
->lruvec_stat_cpu
->count
[idx
]);
764 if (unlikely(abs(x
) > MEMCG_CHARGE_BATCH
)) {
765 struct mem_cgroup_per_node
*pi
;
767 for (pi
= pn
; pi
; pi
= parent_nodeinfo(pi
, pgdat
->node_id
))
768 atomic_long_add(x
, &pi
->lruvec_stat
[idx
]);
771 __this_cpu_write(pn
->lruvec_stat_cpu
->count
[idx
], x
);
774 void __mod_lruvec_slab_state(void *p
, enum node_stat_item idx
, int val
)
776 struct page
*page
= virt_to_head_page(p
);
777 pg_data_t
*pgdat
= page_pgdat(page
);
778 struct mem_cgroup
*memcg
;
779 struct lruvec
*lruvec
;
782 memcg
= memcg_from_slab_page(page
);
784 /* Untracked pages have no memcg, no lruvec. Update only the node */
785 if (!memcg
|| memcg
== root_mem_cgroup
) {
786 __mod_node_page_state(pgdat
, idx
, val
);
788 lruvec
= mem_cgroup_lruvec(pgdat
, memcg
);
789 __mod_lruvec_state(lruvec
, idx
, val
);
795 * __count_memcg_events - account VM events in a cgroup
796 * @memcg: the memory cgroup
797 * @idx: the event item
798 * @count: the number of events that occured
800 void __count_memcg_events(struct mem_cgroup
*memcg
, enum vm_event_item idx
,
805 if (mem_cgroup_disabled())
808 x
= count
+ __this_cpu_read(memcg
->vmstats_percpu
->events
[idx
]);
809 if (unlikely(x
> MEMCG_CHARGE_BATCH
)) {
810 struct mem_cgroup
*mi
;
813 * Batch local counters to keep them in sync with
814 * the hierarchical ones.
816 __this_cpu_add(memcg
->vmstats_local
->events
[idx
], x
);
817 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
818 atomic_long_add(x
, &mi
->vmevents
[idx
]);
821 __this_cpu_write(memcg
->vmstats_percpu
->events
[idx
], x
);
824 static unsigned long memcg_events(struct mem_cgroup
*memcg
, int event
)
826 return atomic_long_read(&memcg
->vmevents
[event
]);
829 static unsigned long memcg_events_local(struct mem_cgroup
*memcg
, int event
)
834 for_each_possible_cpu(cpu
)
835 x
+= per_cpu(memcg
->vmstats_local
->events
[event
], cpu
);
839 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
841 bool compound
, int nr_pages
)
844 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
845 * counted as CACHE even if it's on ANON LRU.
848 __mod_memcg_state(memcg
, MEMCG_RSS
, nr_pages
);
850 __mod_memcg_state(memcg
, MEMCG_CACHE
, nr_pages
);
851 if (PageSwapBacked(page
))
852 __mod_memcg_state(memcg
, NR_SHMEM
, nr_pages
);
856 VM_BUG_ON_PAGE(!PageTransHuge(page
), page
);
857 __mod_memcg_state(memcg
, MEMCG_RSS_HUGE
, nr_pages
);
860 /* pagein of a big page is an event. So, ignore page size */
862 __count_memcg_events(memcg
, PGPGIN
, 1);
864 __count_memcg_events(memcg
, PGPGOUT
, 1);
865 nr_pages
= -nr_pages
; /* for event */
868 __this_cpu_add(memcg
->vmstats_percpu
->nr_page_events
, nr_pages
);
871 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
872 enum mem_cgroup_events_target target
)
874 unsigned long val
, next
;
876 val
= __this_cpu_read(memcg
->vmstats_percpu
->nr_page_events
);
877 next
= __this_cpu_read(memcg
->vmstats_percpu
->targets
[target
]);
878 /* from time_after() in jiffies.h */
879 if ((long)(next
- val
) < 0) {
881 case MEM_CGROUP_TARGET_THRESH
:
882 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
884 case MEM_CGROUP_TARGET_SOFTLIMIT
:
885 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
887 case MEM_CGROUP_TARGET_NUMAINFO
:
888 next
= val
+ NUMAINFO_EVENTS_TARGET
;
893 __this_cpu_write(memcg
->vmstats_percpu
->targets
[target
], next
);
900 * Check events in order.
903 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
905 /* threshold event is triggered in finer grain than soft limit */
906 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
907 MEM_CGROUP_TARGET_THRESH
))) {
909 bool do_numainfo __maybe_unused
;
911 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
912 MEM_CGROUP_TARGET_SOFTLIMIT
);
914 do_numainfo
= mem_cgroup_event_ratelimit(memcg
,
915 MEM_CGROUP_TARGET_NUMAINFO
);
917 mem_cgroup_threshold(memcg
);
918 if (unlikely(do_softlimit
))
919 mem_cgroup_update_tree(memcg
, page
);
921 if (unlikely(do_numainfo
))
922 atomic_inc(&memcg
->numainfo_events
);
927 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
930 * mm_update_next_owner() may clear mm->owner to NULL
931 * if it races with swapoff, page migration, etc.
932 * So this can be called with p == NULL.
937 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
939 EXPORT_SYMBOL(mem_cgroup_from_task
);
942 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
943 * @mm: mm from which memcg should be extracted. It can be NULL.
945 * Obtain a reference on mm->memcg and returns it if successful. Otherwise
946 * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is
949 struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
951 struct mem_cgroup
*memcg
;
953 if (mem_cgroup_disabled())
959 * Page cache insertions can happen withou an
960 * actual mm context, e.g. during disk probing
961 * on boot, loopback IO, acct() writes etc.
964 memcg
= root_mem_cgroup
;
966 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
967 if (unlikely(!memcg
))
968 memcg
= root_mem_cgroup
;
970 } while (!css_tryget_online(&memcg
->css
));
974 EXPORT_SYMBOL(get_mem_cgroup_from_mm
);
977 * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
978 * @page: page from which memcg should be extracted.
980 * Obtain a reference on page->memcg and returns it if successful. Otherwise
981 * root_mem_cgroup is returned.
983 struct mem_cgroup
*get_mem_cgroup_from_page(struct page
*page
)
985 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
987 if (mem_cgroup_disabled())
991 if (!memcg
|| !css_tryget_online(&memcg
->css
))
992 memcg
= root_mem_cgroup
;
996 EXPORT_SYMBOL(get_mem_cgroup_from_page
);
999 * If current->active_memcg is non-NULL, do not fallback to current->mm->memcg.
1001 static __always_inline
struct mem_cgroup
*get_mem_cgroup_from_current(void)
1003 if (unlikely(current
->active_memcg
)) {
1004 struct mem_cgroup
*memcg
= root_mem_cgroup
;
1007 if (css_tryget_online(¤t
->active_memcg
->css
))
1008 memcg
= current
->active_memcg
;
1012 return get_mem_cgroup_from_mm(current
->mm
);
1016 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1017 * @root: hierarchy root
1018 * @prev: previously returned memcg, NULL on first invocation
1019 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1021 * Returns references to children of the hierarchy below @root, or
1022 * @root itself, or %NULL after a full round-trip.
1024 * Caller must pass the return value in @prev on subsequent
1025 * invocations for reference counting, or use mem_cgroup_iter_break()
1026 * to cancel a hierarchy walk before the round-trip is complete.
1028 * Reclaimers can specify a node and a priority level in @reclaim to
1029 * divide up the memcgs in the hierarchy among all concurrent
1030 * reclaimers operating on the same node and priority.
1032 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1033 struct mem_cgroup
*prev
,
1034 struct mem_cgroup_reclaim_cookie
*reclaim
)
1036 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1037 struct cgroup_subsys_state
*css
= NULL
;
1038 struct mem_cgroup
*memcg
= NULL
;
1039 struct mem_cgroup
*pos
= NULL
;
1041 if (mem_cgroup_disabled())
1045 root
= root_mem_cgroup
;
1047 if (prev
&& !reclaim
)
1050 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1059 struct mem_cgroup_per_node
*mz
;
1061 mz
= mem_cgroup_nodeinfo(root
, reclaim
->pgdat
->node_id
);
1062 iter
= &mz
->iter
[reclaim
->priority
];
1064 if (prev
&& reclaim
->generation
!= iter
->generation
)
1068 pos
= READ_ONCE(iter
->position
);
1069 if (!pos
|| css_tryget(&pos
->css
))
1072 * css reference reached zero, so iter->position will
1073 * be cleared by ->css_released. However, we should not
1074 * rely on this happening soon, because ->css_released
1075 * is called from a work queue, and by busy-waiting we
1076 * might block it. So we clear iter->position right
1079 (void)cmpxchg(&iter
->position
, pos
, NULL
);
1087 css
= css_next_descendant_pre(css
, &root
->css
);
1090 * Reclaimers share the hierarchy walk, and a
1091 * new one might jump in right at the end of
1092 * the hierarchy - make sure they see at least
1093 * one group and restart from the beginning.
1101 * Verify the css and acquire a reference. The root
1102 * is provided by the caller, so we know it's alive
1103 * and kicking, and don't take an extra reference.
1105 memcg
= mem_cgroup_from_css(css
);
1107 if (css
== &root
->css
)
1110 if (css_tryget(css
))
1118 * The position could have already been updated by a competing
1119 * thread, so check that the value hasn't changed since we read
1120 * it to avoid reclaiming from the same cgroup twice.
1122 (void)cmpxchg(&iter
->position
, pos
, memcg
);
1130 reclaim
->generation
= iter
->generation
;
1136 if (prev
&& prev
!= root
)
1137 css_put(&prev
->css
);
1143 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1144 * @root: hierarchy root
1145 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1147 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1148 struct mem_cgroup
*prev
)
1151 root
= root_mem_cgroup
;
1152 if (prev
&& prev
!= root
)
1153 css_put(&prev
->css
);
1156 static void __invalidate_reclaim_iterators(struct mem_cgroup
*from
,
1157 struct mem_cgroup
*dead_memcg
)
1159 struct mem_cgroup_reclaim_iter
*iter
;
1160 struct mem_cgroup_per_node
*mz
;
1164 for_each_node(nid
) {
1165 mz
= mem_cgroup_nodeinfo(from
, nid
);
1166 for (i
= 0; i
<= DEF_PRIORITY
; i
++) {
1167 iter
= &mz
->iter
[i
];
1168 cmpxchg(&iter
->position
,
1174 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
1176 struct mem_cgroup
*memcg
= dead_memcg
;
1177 struct mem_cgroup
*last
;
1180 __invalidate_reclaim_iterators(memcg
, dead_memcg
);
1182 } while ((memcg
= parent_mem_cgroup(memcg
)));
1185 * When cgruop1 non-hierarchy mode is used,
1186 * parent_mem_cgroup() does not walk all the way up to the
1187 * cgroup root (root_mem_cgroup). So we have to handle
1188 * dead_memcg from cgroup root separately.
1190 if (last
!= root_mem_cgroup
)
1191 __invalidate_reclaim_iterators(root_mem_cgroup
,
1196 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1197 * @memcg: hierarchy root
1198 * @fn: function to call for each task
1199 * @arg: argument passed to @fn
1201 * This function iterates over tasks attached to @memcg or to any of its
1202 * descendants and calls @fn for each task. If @fn returns a non-zero
1203 * value, the function breaks the iteration loop and returns the value.
1204 * Otherwise, it will iterate over all tasks and return 0.
1206 * This function must not be called for the root memory cgroup.
1208 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
1209 int (*fn
)(struct task_struct
*, void *), void *arg
)
1211 struct mem_cgroup
*iter
;
1214 BUG_ON(memcg
== root_mem_cgroup
);
1216 for_each_mem_cgroup_tree(iter
, memcg
) {
1217 struct css_task_iter it
;
1218 struct task_struct
*task
;
1220 css_task_iter_start(&iter
->css
, CSS_TASK_ITER_PROCS
, &it
);
1221 while (!ret
&& (task
= css_task_iter_next(&it
)))
1222 ret
= fn(task
, arg
);
1223 css_task_iter_end(&it
);
1225 mem_cgroup_iter_break(memcg
, iter
);
1233 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1235 * @pgdat: pgdat of the page
1237 * This function is only safe when following the LRU page isolation
1238 * and putback protocol: the LRU lock must be held, and the page must
1239 * either be PageLRU() or the caller must have isolated/allocated it.
1241 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct pglist_data
*pgdat
)
1243 struct mem_cgroup_per_node
*mz
;
1244 struct mem_cgroup
*memcg
;
1245 struct lruvec
*lruvec
;
1247 if (mem_cgroup_disabled()) {
1248 lruvec
= &pgdat
->lruvec
;
1252 memcg
= page
->mem_cgroup
;
1254 * Swapcache readahead pages are added to the LRU - and
1255 * possibly migrated - before they are charged.
1258 memcg
= root_mem_cgroup
;
1260 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
1261 lruvec
= &mz
->lruvec
;
1264 * Since a node can be onlined after the mem_cgroup was created,
1265 * we have to be prepared to initialize lruvec->zone here;
1266 * and if offlined then reonlined, we need to reinitialize it.
1268 if (unlikely(lruvec
->pgdat
!= pgdat
))
1269 lruvec
->pgdat
= pgdat
;
1274 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1275 * @lruvec: mem_cgroup per zone lru vector
1276 * @lru: index of lru list the page is sitting on
1277 * @zid: zone id of the accounted pages
1278 * @nr_pages: positive when adding or negative when removing
1280 * This function must be called under lru_lock, just before a page is added
1281 * to or just after a page is removed from an lru list (that ordering being
1282 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1284 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1285 int zid
, int nr_pages
)
1287 struct mem_cgroup_per_node
*mz
;
1288 unsigned long *lru_size
;
1291 if (mem_cgroup_disabled())
1294 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1295 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1298 *lru_size
+= nr_pages
;
1301 if (WARN_ONCE(size
< 0,
1302 "%s(%p, %d, %d): lru_size %ld\n",
1303 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1309 *lru_size
+= nr_pages
;
1313 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1314 * @memcg: the memory cgroup
1316 * Returns the maximum amount of memory @mem can be charged with, in
1319 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1321 unsigned long margin
= 0;
1322 unsigned long count
;
1323 unsigned long limit
;
1325 count
= page_counter_read(&memcg
->memory
);
1326 limit
= READ_ONCE(memcg
->memory
.max
);
1328 margin
= limit
- count
;
1330 if (do_memsw_account()) {
1331 count
= page_counter_read(&memcg
->memsw
);
1332 limit
= READ_ONCE(memcg
->memsw
.max
);
1334 margin
= min(margin
, limit
- count
);
1343 * A routine for checking "mem" is under move_account() or not.
1345 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1346 * moving cgroups. This is for waiting at high-memory pressure
1349 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1351 struct mem_cgroup
*from
;
1352 struct mem_cgroup
*to
;
1355 * Unlike task_move routines, we access mc.to, mc.from not under
1356 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1358 spin_lock(&mc
.lock
);
1364 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1365 mem_cgroup_is_descendant(to
, memcg
);
1367 spin_unlock(&mc
.lock
);
1371 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1373 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1374 if (mem_cgroup_under_move(memcg
)) {
1376 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1377 /* moving charge context might have finished. */
1380 finish_wait(&mc
.waitq
, &wait
);
1387 static char *memory_stat_format(struct mem_cgroup
*memcg
)
1392 seq_buf_init(&s
, kmalloc(PAGE_SIZE
, GFP_KERNEL
), PAGE_SIZE
);
1397 * Provide statistics on the state of the memory subsystem as
1398 * well as cumulative event counters that show past behavior.
1400 * This list is ordered following a combination of these gradients:
1401 * 1) generic big picture -> specifics and details
1402 * 2) reflecting userspace activity -> reflecting kernel heuristics
1404 * Current memory state:
1407 seq_buf_printf(&s
, "anon %llu\n",
1408 (u64
)memcg_page_state(memcg
, MEMCG_RSS
) *
1410 seq_buf_printf(&s
, "file %llu\n",
1411 (u64
)memcg_page_state(memcg
, MEMCG_CACHE
) *
1413 seq_buf_printf(&s
, "kernel_stack %llu\n",
1414 (u64
)memcg_page_state(memcg
, MEMCG_KERNEL_STACK_KB
) *
1416 seq_buf_printf(&s
, "slab %llu\n",
1417 (u64
)(memcg_page_state(memcg
, NR_SLAB_RECLAIMABLE
) +
1418 memcg_page_state(memcg
, NR_SLAB_UNRECLAIMABLE
)) *
1420 seq_buf_printf(&s
, "sock %llu\n",
1421 (u64
)memcg_page_state(memcg
, MEMCG_SOCK
) *
1424 seq_buf_printf(&s
, "shmem %llu\n",
1425 (u64
)memcg_page_state(memcg
, NR_SHMEM
) *
1427 seq_buf_printf(&s
, "file_mapped %llu\n",
1428 (u64
)memcg_page_state(memcg
, NR_FILE_MAPPED
) *
1430 seq_buf_printf(&s
, "file_dirty %llu\n",
1431 (u64
)memcg_page_state(memcg
, NR_FILE_DIRTY
) *
1433 seq_buf_printf(&s
, "file_writeback %llu\n",
1434 (u64
)memcg_page_state(memcg
, NR_WRITEBACK
) *
1438 * TODO: We should eventually replace our own MEMCG_RSS_HUGE counter
1439 * with the NR_ANON_THP vm counter, but right now it's a pain in the
1440 * arse because it requires migrating the work out of rmap to a place
1441 * where the page->mem_cgroup is set up and stable.
1443 seq_buf_printf(&s
, "anon_thp %llu\n",
1444 (u64
)memcg_page_state(memcg
, MEMCG_RSS_HUGE
) *
1447 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1448 seq_buf_printf(&s
, "%s %llu\n", mem_cgroup_lru_names
[i
],
1449 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
1452 seq_buf_printf(&s
, "slab_reclaimable %llu\n",
1453 (u64
)memcg_page_state(memcg
, NR_SLAB_RECLAIMABLE
) *
1455 seq_buf_printf(&s
, "slab_unreclaimable %llu\n",
1456 (u64
)memcg_page_state(memcg
, NR_SLAB_UNRECLAIMABLE
) *
1459 /* Accumulated memory events */
1461 seq_buf_printf(&s
, "pgfault %lu\n", memcg_events(memcg
, PGFAULT
));
1462 seq_buf_printf(&s
, "pgmajfault %lu\n", memcg_events(memcg
, PGMAJFAULT
));
1464 seq_buf_printf(&s
, "workingset_refault %lu\n",
1465 memcg_page_state(memcg
, WORKINGSET_REFAULT
));
1466 seq_buf_printf(&s
, "workingset_activate %lu\n",
1467 memcg_page_state(memcg
, WORKINGSET_ACTIVATE
));
1468 seq_buf_printf(&s
, "workingset_nodereclaim %lu\n",
1469 memcg_page_state(memcg
, WORKINGSET_NODERECLAIM
));
1471 seq_buf_printf(&s
, "pgrefill %lu\n", memcg_events(memcg
, PGREFILL
));
1472 seq_buf_printf(&s
, "pgscan %lu\n",
1473 memcg_events(memcg
, PGSCAN_KSWAPD
) +
1474 memcg_events(memcg
, PGSCAN_DIRECT
));
1475 seq_buf_printf(&s
, "pgsteal %lu\n",
1476 memcg_events(memcg
, PGSTEAL_KSWAPD
) +
1477 memcg_events(memcg
, PGSTEAL_DIRECT
));
1478 seq_buf_printf(&s
, "pgactivate %lu\n", memcg_events(memcg
, PGACTIVATE
));
1479 seq_buf_printf(&s
, "pgdeactivate %lu\n", memcg_events(memcg
, PGDEACTIVATE
));
1480 seq_buf_printf(&s
, "pglazyfree %lu\n", memcg_events(memcg
, PGLAZYFREE
));
1481 seq_buf_printf(&s
, "pglazyfreed %lu\n", memcg_events(memcg
, PGLAZYFREED
));
1483 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1484 seq_buf_printf(&s
, "thp_fault_alloc %lu\n",
1485 memcg_events(memcg
, THP_FAULT_ALLOC
));
1486 seq_buf_printf(&s
, "thp_collapse_alloc %lu\n",
1487 memcg_events(memcg
, THP_COLLAPSE_ALLOC
));
1488 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1490 /* The above should easily fit into one page */
1491 WARN_ON_ONCE(seq_buf_has_overflowed(&s
));
1496 #define K(x) ((x) << (PAGE_SHIFT-10))
1498 * mem_cgroup_print_oom_context: Print OOM information relevant to
1499 * memory controller.
1500 * @memcg: The memory cgroup that went over limit
1501 * @p: Task that is going to be killed
1503 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1506 void mem_cgroup_print_oom_context(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1511 pr_cont(",oom_memcg=");
1512 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1514 pr_cont(",global_oom");
1516 pr_cont(",task_memcg=");
1517 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1523 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1524 * memory controller.
1525 * @memcg: The memory cgroup that went over limit
1527 void mem_cgroup_print_oom_meminfo(struct mem_cgroup
*memcg
)
1531 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1532 K((u64
)page_counter_read(&memcg
->memory
)),
1533 K((u64
)memcg
->memory
.max
), memcg
->memory
.failcnt
);
1534 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1535 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1536 K((u64
)page_counter_read(&memcg
->swap
)),
1537 K((u64
)memcg
->swap
.max
), memcg
->swap
.failcnt
);
1539 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1540 K((u64
)page_counter_read(&memcg
->memsw
)),
1541 K((u64
)memcg
->memsw
.max
), memcg
->memsw
.failcnt
);
1542 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1543 K((u64
)page_counter_read(&memcg
->kmem
)),
1544 K((u64
)memcg
->kmem
.max
), memcg
->kmem
.failcnt
);
1547 pr_info("Memory cgroup stats for ");
1548 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1550 buf
= memory_stat_format(memcg
);
1558 * Return the memory (and swap, if configured) limit for a memcg.
1560 unsigned long mem_cgroup_get_max(struct mem_cgroup
*memcg
)
1564 max
= memcg
->memory
.max
;
1565 if (mem_cgroup_swappiness(memcg
)) {
1566 unsigned long memsw_max
;
1567 unsigned long swap_max
;
1569 memsw_max
= memcg
->memsw
.max
;
1570 swap_max
= memcg
->swap
.max
;
1571 swap_max
= min(swap_max
, (unsigned long)total_swap_pages
);
1572 max
= min(max
+ swap_max
, memsw_max
);
1577 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1580 struct oom_control oc
= {
1584 .gfp_mask
= gfp_mask
,
1589 if (mutex_lock_killable(&oom_lock
))
1592 * A few threads which were not waiting at mutex_lock_killable() can
1593 * fail to bail out. Therefore, check again after holding oom_lock.
1595 ret
= should_force_charge() || out_of_memory(&oc
);
1596 mutex_unlock(&oom_lock
);
1600 #if MAX_NUMNODES > 1
1603 * test_mem_cgroup_node_reclaimable
1604 * @memcg: the target memcg
1605 * @nid: the node ID to be checked.
1606 * @noswap : specify true here if the user wants flle only information.
1608 * This function returns whether the specified memcg contains any
1609 * reclaimable pages on a node. Returns true if there are any reclaimable
1610 * pages in the node.
1612 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup
*memcg
,
1613 int nid
, bool noswap
)
1615 struct lruvec
*lruvec
= mem_cgroup_lruvec(NODE_DATA(nid
), memcg
);
1617 if (lruvec_page_state(lruvec
, NR_INACTIVE_FILE
) ||
1618 lruvec_page_state(lruvec
, NR_ACTIVE_FILE
))
1620 if (noswap
|| !total_swap_pages
)
1622 if (lruvec_page_state(lruvec
, NR_INACTIVE_ANON
) ||
1623 lruvec_page_state(lruvec
, NR_ACTIVE_ANON
))
1630 * Always updating the nodemask is not very good - even if we have an empty
1631 * list or the wrong list here, we can start from some node and traverse all
1632 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1635 static void mem_cgroup_may_update_nodemask(struct mem_cgroup
*memcg
)
1639 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1640 * pagein/pageout changes since the last update.
1642 if (!atomic_read(&memcg
->numainfo_events
))
1644 if (atomic_inc_return(&memcg
->numainfo_updating
) > 1)
1647 /* make a nodemask where this memcg uses memory from */
1648 memcg
->scan_nodes
= node_states
[N_MEMORY
];
1650 for_each_node_mask(nid
, node_states
[N_MEMORY
]) {
1652 if (!test_mem_cgroup_node_reclaimable(memcg
, nid
, false))
1653 node_clear(nid
, memcg
->scan_nodes
);
1656 atomic_set(&memcg
->numainfo_events
, 0);
1657 atomic_set(&memcg
->numainfo_updating
, 0);
1661 * Selecting a node where we start reclaim from. Because what we need is just
1662 * reducing usage counter, start from anywhere is O,K. Considering
1663 * memory reclaim from current node, there are pros. and cons.
1665 * Freeing memory from current node means freeing memory from a node which
1666 * we'll use or we've used. So, it may make LRU bad. And if several threads
1667 * hit limits, it will see a contention on a node. But freeing from remote
1668 * node means more costs for memory reclaim because of memory latency.
1670 * Now, we use round-robin. Better algorithm is welcomed.
1672 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1676 mem_cgroup_may_update_nodemask(memcg
);
1677 node
= memcg
->last_scanned_node
;
1679 node
= next_node_in(node
, memcg
->scan_nodes
);
1681 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1682 * last time it really checked all the LRUs due to rate limiting.
1683 * Fallback to the current node in that case for simplicity.
1685 if (unlikely(node
== MAX_NUMNODES
))
1686 node
= numa_node_id();
1688 memcg
->last_scanned_node
= node
;
1692 int mem_cgroup_select_victim_node(struct mem_cgroup
*memcg
)
1698 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1701 unsigned long *total_scanned
)
1703 struct mem_cgroup
*victim
= NULL
;
1706 unsigned long excess
;
1707 unsigned long nr_scanned
;
1708 struct mem_cgroup_reclaim_cookie reclaim
= {
1713 excess
= soft_limit_excess(root_memcg
);
1716 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1721 * If we have not been able to reclaim
1722 * anything, it might because there are
1723 * no reclaimable pages under this hierarchy
1728 * We want to do more targeted reclaim.
1729 * excess >> 2 is not to excessive so as to
1730 * reclaim too much, nor too less that we keep
1731 * coming back to reclaim from this cgroup
1733 if (total
>= (excess
>> 2) ||
1734 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1739 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1740 pgdat
, &nr_scanned
);
1741 *total_scanned
+= nr_scanned
;
1742 if (!soft_limit_excess(root_memcg
))
1745 mem_cgroup_iter_break(root_memcg
, victim
);
1749 #ifdef CONFIG_LOCKDEP
1750 static struct lockdep_map memcg_oom_lock_dep_map
= {
1751 .name
= "memcg_oom_lock",
1755 static DEFINE_SPINLOCK(memcg_oom_lock
);
1758 * Check OOM-Killer is already running under our hierarchy.
1759 * If someone is running, return false.
1761 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1763 struct mem_cgroup
*iter
, *failed
= NULL
;
1765 spin_lock(&memcg_oom_lock
);
1767 for_each_mem_cgroup_tree(iter
, memcg
) {
1768 if (iter
->oom_lock
) {
1770 * this subtree of our hierarchy is already locked
1771 * so we cannot give a lock.
1774 mem_cgroup_iter_break(memcg
, iter
);
1777 iter
->oom_lock
= true;
1782 * OK, we failed to lock the whole subtree so we have
1783 * to clean up what we set up to the failing subtree
1785 for_each_mem_cgroup_tree(iter
, memcg
) {
1786 if (iter
== failed
) {
1787 mem_cgroup_iter_break(memcg
, iter
);
1790 iter
->oom_lock
= false;
1793 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1795 spin_unlock(&memcg_oom_lock
);
1800 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1802 struct mem_cgroup
*iter
;
1804 spin_lock(&memcg_oom_lock
);
1805 mutex_release(&memcg_oom_lock_dep_map
, 1, _RET_IP_
);
1806 for_each_mem_cgroup_tree(iter
, memcg
)
1807 iter
->oom_lock
= false;
1808 spin_unlock(&memcg_oom_lock
);
1811 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1813 struct mem_cgroup
*iter
;
1815 spin_lock(&memcg_oom_lock
);
1816 for_each_mem_cgroup_tree(iter
, memcg
)
1818 spin_unlock(&memcg_oom_lock
);
1821 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1823 struct mem_cgroup
*iter
;
1826 * When a new child is created while the hierarchy is under oom,
1827 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1829 spin_lock(&memcg_oom_lock
);
1830 for_each_mem_cgroup_tree(iter
, memcg
)
1831 if (iter
->under_oom
> 0)
1833 spin_unlock(&memcg_oom_lock
);
1836 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1838 struct oom_wait_info
{
1839 struct mem_cgroup
*memcg
;
1840 wait_queue_entry_t wait
;
1843 static int memcg_oom_wake_function(wait_queue_entry_t
*wait
,
1844 unsigned mode
, int sync
, void *arg
)
1846 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1847 struct mem_cgroup
*oom_wait_memcg
;
1848 struct oom_wait_info
*oom_wait_info
;
1850 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1851 oom_wait_memcg
= oom_wait_info
->memcg
;
1853 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1854 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1856 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1859 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1862 * For the following lockless ->under_oom test, the only required
1863 * guarantee is that it must see the state asserted by an OOM when
1864 * this function is called as a result of userland actions
1865 * triggered by the notification of the OOM. This is trivially
1866 * achieved by invoking mem_cgroup_mark_under_oom() before
1867 * triggering notification.
1869 if (memcg
&& memcg
->under_oom
)
1870 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1880 static enum oom_status
mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1882 enum oom_status ret
;
1885 if (order
> PAGE_ALLOC_COSTLY_ORDER
)
1888 memcg_memory_event(memcg
, MEMCG_OOM
);
1891 * We are in the middle of the charge context here, so we
1892 * don't want to block when potentially sitting on a callstack
1893 * that holds all kinds of filesystem and mm locks.
1895 * cgroup1 allows disabling the OOM killer and waiting for outside
1896 * handling until the charge can succeed; remember the context and put
1897 * the task to sleep at the end of the page fault when all locks are
1900 * On the other hand, in-kernel OOM killer allows for an async victim
1901 * memory reclaim (oom_reaper) and that means that we are not solely
1902 * relying on the oom victim to make a forward progress and we can
1903 * invoke the oom killer here.
1905 * Please note that mem_cgroup_out_of_memory might fail to find a
1906 * victim and then we have to bail out from the charge path.
1908 if (memcg
->oom_kill_disable
) {
1909 if (!current
->in_user_fault
)
1911 css_get(&memcg
->css
);
1912 current
->memcg_in_oom
= memcg
;
1913 current
->memcg_oom_gfp_mask
= mask
;
1914 current
->memcg_oom_order
= order
;
1919 mem_cgroup_mark_under_oom(memcg
);
1921 locked
= mem_cgroup_oom_trylock(memcg
);
1924 mem_cgroup_oom_notify(memcg
);
1926 mem_cgroup_unmark_under_oom(memcg
);
1927 if (mem_cgroup_out_of_memory(memcg
, mask
, order
))
1933 mem_cgroup_oom_unlock(memcg
);
1939 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1940 * @handle: actually kill/wait or just clean up the OOM state
1942 * This has to be called at the end of a page fault if the memcg OOM
1943 * handler was enabled.
1945 * Memcg supports userspace OOM handling where failed allocations must
1946 * sleep on a waitqueue until the userspace task resolves the
1947 * situation. Sleeping directly in the charge context with all kinds
1948 * of locks held is not a good idea, instead we remember an OOM state
1949 * in the task and mem_cgroup_oom_synchronize() has to be called at
1950 * the end of the page fault to complete the OOM handling.
1952 * Returns %true if an ongoing memcg OOM situation was detected and
1953 * completed, %false otherwise.
1955 bool mem_cgroup_oom_synchronize(bool handle
)
1957 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1958 struct oom_wait_info owait
;
1961 /* OOM is global, do not handle */
1968 owait
.memcg
= memcg
;
1969 owait
.wait
.flags
= 0;
1970 owait
.wait
.func
= memcg_oom_wake_function
;
1971 owait
.wait
.private = current
;
1972 INIT_LIST_HEAD(&owait
.wait
.entry
);
1974 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1975 mem_cgroup_mark_under_oom(memcg
);
1977 locked
= mem_cgroup_oom_trylock(memcg
);
1980 mem_cgroup_oom_notify(memcg
);
1982 if (locked
&& !memcg
->oom_kill_disable
) {
1983 mem_cgroup_unmark_under_oom(memcg
);
1984 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1985 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1986 current
->memcg_oom_order
);
1989 mem_cgroup_unmark_under_oom(memcg
);
1990 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1994 mem_cgroup_oom_unlock(memcg
);
1996 * There is no guarantee that an OOM-lock contender
1997 * sees the wakeups triggered by the OOM kill
1998 * uncharges. Wake any sleepers explicitely.
2000 memcg_oom_recover(memcg
);
2003 current
->memcg_in_oom
= NULL
;
2004 css_put(&memcg
->css
);
2009 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
2010 * @victim: task to be killed by the OOM killer
2011 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
2013 * Returns a pointer to a memory cgroup, which has to be cleaned up
2014 * by killing all belonging OOM-killable tasks.
2016 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
2018 struct mem_cgroup
*mem_cgroup_get_oom_group(struct task_struct
*victim
,
2019 struct mem_cgroup
*oom_domain
)
2021 struct mem_cgroup
*oom_group
= NULL
;
2022 struct mem_cgroup
*memcg
;
2024 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2028 oom_domain
= root_mem_cgroup
;
2032 memcg
= mem_cgroup_from_task(victim
);
2033 if (memcg
== root_mem_cgroup
)
2037 * Traverse the memory cgroup hierarchy from the victim task's
2038 * cgroup up to the OOMing cgroup (or root) to find the
2039 * highest-level memory cgroup with oom.group set.
2041 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
2042 if (memcg
->oom_group
)
2045 if (memcg
== oom_domain
)
2050 css_get(&oom_group
->css
);
2057 void mem_cgroup_print_oom_group(struct mem_cgroup
*memcg
)
2059 pr_info("Tasks in ");
2060 pr_cont_cgroup_path(memcg
->css
.cgroup
);
2061 pr_cont(" are going to be killed due to memory.oom.group set\n");
2065 * lock_page_memcg - lock a page->mem_cgroup binding
2068 * This function protects unlocked LRU pages from being moved to
2071 * It ensures lifetime of the returned memcg. Caller is responsible
2072 * for the lifetime of the page; __unlock_page_memcg() is available
2073 * when @page might get freed inside the locked section.
2075 struct mem_cgroup
*lock_page_memcg(struct page
*page
)
2077 struct mem_cgroup
*memcg
;
2078 unsigned long flags
;
2081 * The RCU lock is held throughout the transaction. The fast
2082 * path can get away without acquiring the memcg->move_lock
2083 * because page moving starts with an RCU grace period.
2085 * The RCU lock also protects the memcg from being freed when
2086 * the page state that is going to change is the only thing
2087 * preventing the page itself from being freed. E.g. writeback
2088 * doesn't hold a page reference and relies on PG_writeback to
2089 * keep off truncation, migration and so forth.
2093 if (mem_cgroup_disabled())
2096 memcg
= page
->mem_cgroup
;
2097 if (unlikely(!memcg
))
2100 if (atomic_read(&memcg
->moving_account
) <= 0)
2103 spin_lock_irqsave(&memcg
->move_lock
, flags
);
2104 if (memcg
!= page
->mem_cgroup
) {
2105 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2110 * When charge migration first begins, we can have locked and
2111 * unlocked page stat updates happening concurrently. Track
2112 * the task who has the lock for unlock_page_memcg().
2114 memcg
->move_lock_task
= current
;
2115 memcg
->move_lock_flags
= flags
;
2119 EXPORT_SYMBOL(lock_page_memcg
);
2122 * __unlock_page_memcg - unlock and unpin a memcg
2125 * Unlock and unpin a memcg returned by lock_page_memcg().
2127 void __unlock_page_memcg(struct mem_cgroup
*memcg
)
2129 if (memcg
&& memcg
->move_lock_task
== current
) {
2130 unsigned long flags
= memcg
->move_lock_flags
;
2132 memcg
->move_lock_task
= NULL
;
2133 memcg
->move_lock_flags
= 0;
2135 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2142 * unlock_page_memcg - unlock a page->mem_cgroup binding
2145 void unlock_page_memcg(struct page
*page
)
2147 __unlock_page_memcg(page
->mem_cgroup
);
2149 EXPORT_SYMBOL(unlock_page_memcg
);
2151 struct memcg_stock_pcp
{
2152 struct mem_cgroup
*cached
; /* this never be root cgroup */
2153 unsigned int nr_pages
;
2154 struct work_struct work
;
2155 unsigned long flags
;
2156 #define FLUSHING_CACHED_CHARGE 0
2158 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2159 static DEFINE_MUTEX(percpu_charge_mutex
);
2162 * consume_stock: Try to consume stocked charge on this cpu.
2163 * @memcg: memcg to consume from.
2164 * @nr_pages: how many pages to charge.
2166 * The charges will only happen if @memcg matches the current cpu's memcg
2167 * stock, and at least @nr_pages are available in that stock. Failure to
2168 * service an allocation will refill the stock.
2170 * returns true if successful, false otherwise.
2172 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2174 struct memcg_stock_pcp
*stock
;
2175 unsigned long flags
;
2178 if (nr_pages
> MEMCG_CHARGE_BATCH
)
2181 local_irq_save(flags
);
2183 stock
= this_cpu_ptr(&memcg_stock
);
2184 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
2185 stock
->nr_pages
-= nr_pages
;
2189 local_irq_restore(flags
);
2195 * Returns stocks cached in percpu and reset cached information.
2197 static void drain_stock(struct memcg_stock_pcp
*stock
)
2199 struct mem_cgroup
*old
= stock
->cached
;
2201 if (stock
->nr_pages
) {
2202 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
2203 if (do_memsw_account())
2204 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
2205 css_put_many(&old
->css
, stock
->nr_pages
);
2206 stock
->nr_pages
= 0;
2208 stock
->cached
= NULL
;
2211 static void drain_local_stock(struct work_struct
*dummy
)
2213 struct memcg_stock_pcp
*stock
;
2214 unsigned long flags
;
2217 * The only protection from memory hotplug vs. drain_stock races is
2218 * that we always operate on local CPU stock here with IRQ disabled
2220 local_irq_save(flags
);
2222 stock
= this_cpu_ptr(&memcg_stock
);
2224 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2226 local_irq_restore(flags
);
2230 * Cache charges(val) to local per_cpu area.
2231 * This will be consumed by consume_stock() function, later.
2233 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2235 struct memcg_stock_pcp
*stock
;
2236 unsigned long flags
;
2238 local_irq_save(flags
);
2240 stock
= this_cpu_ptr(&memcg_stock
);
2241 if (stock
->cached
!= memcg
) { /* reset if necessary */
2243 stock
->cached
= memcg
;
2245 stock
->nr_pages
+= nr_pages
;
2247 if (stock
->nr_pages
> MEMCG_CHARGE_BATCH
)
2250 local_irq_restore(flags
);
2254 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2255 * of the hierarchy under it.
2257 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
2261 /* If someone's already draining, avoid adding running more workers. */
2262 if (!mutex_trylock(&percpu_charge_mutex
))
2265 * Notify other cpus that system-wide "drain" is running
2266 * We do not care about races with the cpu hotplug because cpu down
2267 * as well as workers from this path always operate on the local
2268 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2271 for_each_online_cpu(cpu
) {
2272 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2273 struct mem_cgroup
*memcg
;
2277 memcg
= stock
->cached
;
2278 if (memcg
&& stock
->nr_pages
&&
2279 mem_cgroup_is_descendant(memcg
, root_memcg
))
2284 !test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2286 drain_local_stock(&stock
->work
);
2288 schedule_work_on(cpu
, &stock
->work
);
2292 mutex_unlock(&percpu_charge_mutex
);
2295 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
2297 struct memcg_stock_pcp
*stock
;
2298 struct mem_cgroup
*memcg
, *mi
;
2300 stock
= &per_cpu(memcg_stock
, cpu
);
2303 for_each_mem_cgroup(memcg
) {
2306 for (i
= 0; i
< MEMCG_NR_STAT
; i
++) {
2310 x
= this_cpu_xchg(memcg
->vmstats_percpu
->stat
[i
], 0);
2312 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
2313 atomic_long_add(x
, &memcg
->vmstats
[i
]);
2315 if (i
>= NR_VM_NODE_STAT_ITEMS
)
2318 for_each_node(nid
) {
2319 struct mem_cgroup_per_node
*pn
;
2321 pn
= mem_cgroup_nodeinfo(memcg
, nid
);
2322 x
= this_cpu_xchg(pn
->lruvec_stat_cpu
->count
[i
], 0);
2325 atomic_long_add(x
, &pn
->lruvec_stat
[i
]);
2326 } while ((pn
= parent_nodeinfo(pn
, nid
)));
2330 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++) {
2333 x
= this_cpu_xchg(memcg
->vmstats_percpu
->events
[i
], 0);
2335 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
2336 atomic_long_add(x
, &memcg
->vmevents
[i
]);
2343 static void reclaim_high(struct mem_cgroup
*memcg
,
2344 unsigned int nr_pages
,
2348 if (page_counter_read(&memcg
->memory
) <= memcg
->high
)
2350 memcg_memory_event(memcg
, MEMCG_HIGH
);
2351 try_to_free_mem_cgroup_pages(memcg
, nr_pages
, gfp_mask
, true);
2352 } while ((memcg
= parent_mem_cgroup(memcg
)));
2355 static void high_work_func(struct work_struct
*work
)
2357 struct mem_cgroup
*memcg
;
2359 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
2360 reclaim_high(memcg
, MEMCG_CHARGE_BATCH
, GFP_KERNEL
);
2364 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2365 * enough to still cause a significant slowdown in most cases, while still
2366 * allowing diagnostics and tracing to proceed without becoming stuck.
2368 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2371 * When calculating the delay, we use these either side of the exponentiation to
2372 * maintain precision and scale to a reasonable number of jiffies (see the table
2375 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2376 * overage ratio to a delay.
2377 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down down the
2378 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2379 * to produce a reasonable delay curve.
2381 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2382 * reasonable delay curve compared to precision-adjusted overage, not
2383 * penalising heavily at first, but still making sure that growth beyond the
2384 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2385 * example, with a high of 100 megabytes:
2387 * +-------+------------------------+
2388 * | usage | time to allocate in ms |
2389 * +-------+------------------------+
2411 * +-------+------------------------+
2413 #define MEMCG_DELAY_PRECISION_SHIFT 20
2414 #define MEMCG_DELAY_SCALING_SHIFT 14
2417 * Scheduled by try_charge() to be executed from the userland return path
2418 * and reclaims memory over the high limit.
2420 void mem_cgroup_handle_over_high(void)
2422 unsigned long usage
, high
, clamped_high
;
2423 unsigned long pflags
;
2424 unsigned long penalty_jiffies
, overage
;
2425 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
2426 struct mem_cgroup
*memcg
;
2428 if (likely(!nr_pages
))
2431 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2432 reclaim_high(memcg
, nr_pages
, GFP_KERNEL
);
2433 current
->memcg_nr_pages_over_high
= 0;
2436 * memory.high is breached and reclaim is unable to keep up. Throttle
2437 * allocators proactively to slow down excessive growth.
2439 * We use overage compared to memory.high to calculate the number of
2440 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2441 * fairly lenient on small overages, and increasingly harsh when the
2442 * memcg in question makes it clear that it has no intention of stopping
2443 * its crazy behaviour, so we exponentially increase the delay based on
2447 usage
= page_counter_read(&memcg
->memory
);
2448 high
= READ_ONCE(memcg
->high
);
2454 * Prevent division by 0 in overage calculation by acting as if it was a
2455 * threshold of 1 page
2457 clamped_high
= max(high
, 1UL);
2459 overage
= div_u64((u64
)(usage
- high
) << MEMCG_DELAY_PRECISION_SHIFT
,
2462 penalty_jiffies
= ((u64
)overage
* overage
* HZ
)
2463 >> (MEMCG_DELAY_PRECISION_SHIFT
+ MEMCG_DELAY_SCALING_SHIFT
);
2466 * Factor in the task's own contribution to the overage, such that four
2467 * N-sized allocations are throttled approximately the same as one
2468 * 4N-sized allocation.
2470 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2471 * larger the current charge patch is than that.
2473 penalty_jiffies
= penalty_jiffies
* nr_pages
/ MEMCG_CHARGE_BATCH
;
2476 * Clamp the max delay per usermode return so as to still keep the
2477 * application moving forwards and also permit diagnostics, albeit
2480 penalty_jiffies
= min(penalty_jiffies
, MEMCG_MAX_HIGH_DELAY_JIFFIES
);
2483 * Don't sleep if the amount of jiffies this memcg owes us is so low
2484 * that it's not even worth doing, in an attempt to be nice to those who
2485 * go only a small amount over their memory.high value and maybe haven't
2486 * been aggressively reclaimed enough yet.
2488 if (penalty_jiffies
<= HZ
/ 100)
2492 * If we exit early, we're guaranteed to die (since
2493 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2494 * need to account for any ill-begotten jiffies to pay them off later.
2496 psi_memstall_enter(&pflags
);
2497 schedule_timeout_killable(penalty_jiffies
);
2498 psi_memstall_leave(&pflags
);
2501 css_put(&memcg
->css
);
2504 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2505 unsigned int nr_pages
)
2507 unsigned int batch
= max(MEMCG_CHARGE_BATCH
, nr_pages
);
2508 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2509 struct mem_cgroup
*mem_over_limit
;
2510 struct page_counter
*counter
;
2511 unsigned long nr_reclaimed
;
2512 bool may_swap
= true;
2513 bool drained
= false;
2514 enum oom_status oom_status
;
2516 if (mem_cgroup_is_root(memcg
))
2519 if (consume_stock(memcg
, nr_pages
))
2522 if (!do_memsw_account() ||
2523 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
2524 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
2526 if (do_memsw_account())
2527 page_counter_uncharge(&memcg
->memsw
, batch
);
2528 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
2530 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
2534 if (batch
> nr_pages
) {
2540 * Unlike in global OOM situations, memcg is not in a physical
2541 * memory shortage. Allow dying and OOM-killed tasks to
2542 * bypass the last charges so that they can exit quickly and
2543 * free their memory.
2545 if (unlikely(should_force_charge()))
2549 * Prevent unbounded recursion when reclaim operations need to
2550 * allocate memory. This might exceed the limits temporarily,
2551 * but we prefer facilitating memory reclaim and getting back
2552 * under the limit over triggering OOM kills in these cases.
2554 if (unlikely(current
->flags
& PF_MEMALLOC
))
2557 if (unlikely(task_in_memcg_oom(current
)))
2560 if (!gfpflags_allow_blocking(gfp_mask
))
2563 memcg_memory_event(mem_over_limit
, MEMCG_MAX
);
2565 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
2566 gfp_mask
, may_swap
);
2568 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2572 drain_all_stock(mem_over_limit
);
2577 if (gfp_mask
& __GFP_NORETRY
)
2580 * Even though the limit is exceeded at this point, reclaim
2581 * may have been able to free some pages. Retry the charge
2582 * before killing the task.
2584 * Only for regular pages, though: huge pages are rather
2585 * unlikely to succeed so close to the limit, and we fall back
2586 * to regular pages anyway in case of failure.
2588 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
2591 * At task move, charge accounts can be doubly counted. So, it's
2592 * better to wait until the end of task_move if something is going on.
2594 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2600 if (gfp_mask
& __GFP_RETRY_MAYFAIL
)
2603 if (gfp_mask
& __GFP_NOFAIL
)
2606 if (fatal_signal_pending(current
))
2610 * keep retrying as long as the memcg oom killer is able to make
2611 * a forward progress or bypass the charge if the oom killer
2612 * couldn't make any progress.
2614 oom_status
= mem_cgroup_oom(mem_over_limit
, gfp_mask
,
2615 get_order(nr_pages
* PAGE_SIZE
));
2616 switch (oom_status
) {
2618 nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2626 if (!(gfp_mask
& __GFP_NOFAIL
))
2630 * The allocation either can't fail or will lead to more memory
2631 * being freed very soon. Allow memory usage go over the limit
2632 * temporarily by force charging it.
2634 page_counter_charge(&memcg
->memory
, nr_pages
);
2635 if (do_memsw_account())
2636 page_counter_charge(&memcg
->memsw
, nr_pages
);
2637 css_get_many(&memcg
->css
, nr_pages
);
2642 css_get_many(&memcg
->css
, batch
);
2643 if (batch
> nr_pages
)
2644 refill_stock(memcg
, batch
- nr_pages
);
2647 * If the hierarchy is above the normal consumption range, schedule
2648 * reclaim on returning to userland. We can perform reclaim here
2649 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2650 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2651 * not recorded as it most likely matches current's and won't
2652 * change in the meantime. As high limit is checked again before
2653 * reclaim, the cost of mismatch is negligible.
2656 if (page_counter_read(&memcg
->memory
) > memcg
->high
) {
2657 /* Don't bother a random interrupted task */
2658 if (in_interrupt()) {
2659 schedule_work(&memcg
->high_work
);
2662 current
->memcg_nr_pages_over_high
+= batch
;
2663 set_notify_resume(current
);
2666 } while ((memcg
= parent_mem_cgroup(memcg
)));
2671 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2673 if (mem_cgroup_is_root(memcg
))
2676 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2677 if (do_memsw_account())
2678 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2680 css_put_many(&memcg
->css
, nr_pages
);
2683 static void lock_page_lru(struct page
*page
, int *isolated
)
2685 pg_data_t
*pgdat
= page_pgdat(page
);
2687 spin_lock_irq(&pgdat
->lru_lock
);
2688 if (PageLRU(page
)) {
2689 struct lruvec
*lruvec
;
2691 lruvec
= mem_cgroup_page_lruvec(page
, pgdat
);
2693 del_page_from_lru_list(page
, lruvec
, page_lru(page
));
2699 static void unlock_page_lru(struct page
*page
, int isolated
)
2701 pg_data_t
*pgdat
= page_pgdat(page
);
2704 struct lruvec
*lruvec
;
2706 lruvec
= mem_cgroup_page_lruvec(page
, pgdat
);
2707 VM_BUG_ON_PAGE(PageLRU(page
), page
);
2709 add_page_to_lru_list(page
, lruvec
, page_lru(page
));
2711 spin_unlock_irq(&pgdat
->lru_lock
);
2714 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
2719 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2722 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2723 * may already be on some other mem_cgroup's LRU. Take care of it.
2726 lock_page_lru(page
, &isolated
);
2729 * Nobody should be changing or seriously looking at
2730 * page->mem_cgroup at this point:
2732 * - the page is uncharged
2734 * - the page is off-LRU
2736 * - an anonymous fault has exclusive page access, except for
2737 * a locked page table
2739 * - a page cache insertion, a swapin fault, or a migration
2740 * have the page locked
2742 page
->mem_cgroup
= memcg
;
2745 unlock_page_lru(page
, isolated
);
2748 #ifdef CONFIG_MEMCG_KMEM
2749 static int memcg_alloc_cache_id(void)
2754 id
= ida_simple_get(&memcg_cache_ida
,
2755 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2759 if (id
< memcg_nr_cache_ids
)
2763 * There's no space for the new id in memcg_caches arrays,
2764 * so we have to grow them.
2766 down_write(&memcg_cache_ids_sem
);
2768 size
= 2 * (id
+ 1);
2769 if (size
< MEMCG_CACHES_MIN_SIZE
)
2770 size
= MEMCG_CACHES_MIN_SIZE
;
2771 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2772 size
= MEMCG_CACHES_MAX_SIZE
;
2774 err
= memcg_update_all_caches(size
);
2776 err
= memcg_update_all_list_lrus(size
);
2778 memcg_nr_cache_ids
= size
;
2780 up_write(&memcg_cache_ids_sem
);
2783 ida_simple_remove(&memcg_cache_ida
, id
);
2789 static void memcg_free_cache_id(int id
)
2791 ida_simple_remove(&memcg_cache_ida
, id
);
2794 struct memcg_kmem_cache_create_work
{
2795 struct mem_cgroup
*memcg
;
2796 struct kmem_cache
*cachep
;
2797 struct work_struct work
;
2800 static void memcg_kmem_cache_create_func(struct work_struct
*w
)
2802 struct memcg_kmem_cache_create_work
*cw
=
2803 container_of(w
, struct memcg_kmem_cache_create_work
, work
);
2804 struct mem_cgroup
*memcg
= cw
->memcg
;
2805 struct kmem_cache
*cachep
= cw
->cachep
;
2807 memcg_create_kmem_cache(memcg
, cachep
);
2809 css_put(&memcg
->css
);
2814 * Enqueue the creation of a per-memcg kmem_cache.
2816 static void memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2817 struct kmem_cache
*cachep
)
2819 struct memcg_kmem_cache_create_work
*cw
;
2821 if (!css_tryget_online(&memcg
->css
))
2824 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
| __GFP_NOWARN
);
2829 cw
->cachep
= cachep
;
2830 INIT_WORK(&cw
->work
, memcg_kmem_cache_create_func
);
2832 queue_work(memcg_kmem_cache_wq
, &cw
->work
);
2835 static inline bool memcg_kmem_bypass(void)
2837 if (in_interrupt() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
2843 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2844 * @cachep: the original global kmem cache
2846 * Return the kmem_cache we're supposed to use for a slab allocation.
2847 * We try to use the current memcg's version of the cache.
2849 * If the cache does not exist yet, if we are the first user of it, we
2850 * create it asynchronously in a workqueue and let the current allocation
2851 * go through with the original cache.
2853 * This function takes a reference to the cache it returns to assure it
2854 * won't get destroyed while we are working with it. Once the caller is
2855 * done with it, memcg_kmem_put_cache() must be called to release the
2858 struct kmem_cache
*memcg_kmem_get_cache(struct kmem_cache
*cachep
)
2860 struct mem_cgroup
*memcg
;
2861 struct kmem_cache
*memcg_cachep
;
2862 struct memcg_cache_array
*arr
;
2865 VM_BUG_ON(!is_root_cache(cachep
));
2867 if (memcg_kmem_bypass())
2872 if (unlikely(current
->active_memcg
))
2873 memcg
= current
->active_memcg
;
2875 memcg
= mem_cgroup_from_task(current
);
2877 if (!memcg
|| memcg
== root_mem_cgroup
)
2880 kmemcg_id
= READ_ONCE(memcg
->kmemcg_id
);
2884 arr
= rcu_dereference(cachep
->memcg_params
.memcg_caches
);
2887 * Make sure we will access the up-to-date value. The code updating
2888 * memcg_caches issues a write barrier to match the data dependency
2889 * barrier inside READ_ONCE() (see memcg_create_kmem_cache()).
2891 memcg_cachep
= READ_ONCE(arr
->entries
[kmemcg_id
]);
2894 * If we are in a safe context (can wait, and not in interrupt
2895 * context), we could be be predictable and return right away.
2896 * This would guarantee that the allocation being performed
2897 * already belongs in the new cache.
2899 * However, there are some clashes that can arrive from locking.
2900 * For instance, because we acquire the slab_mutex while doing
2901 * memcg_create_kmem_cache, this means no further allocation
2902 * could happen with the slab_mutex held. So it's better to
2905 * If the memcg is dying or memcg_cache is about to be released,
2906 * don't bother creating new kmem_caches. Because memcg_cachep
2907 * is ZEROed as the fist step of kmem offlining, we don't need
2908 * percpu_ref_tryget_live() here. css_tryget_online() check in
2909 * memcg_schedule_kmem_cache_create() will prevent us from
2910 * creation of a new kmem_cache.
2912 if (unlikely(!memcg_cachep
))
2913 memcg_schedule_kmem_cache_create(memcg
, cachep
);
2914 else if (percpu_ref_tryget(&memcg_cachep
->memcg_params
.refcnt
))
2915 cachep
= memcg_cachep
;
2922 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2923 * @cachep: the cache returned by memcg_kmem_get_cache
2925 void memcg_kmem_put_cache(struct kmem_cache
*cachep
)
2927 if (!is_root_cache(cachep
))
2928 percpu_ref_put(&cachep
->memcg_params
.refcnt
);
2932 * __memcg_kmem_charge_memcg: charge a kmem page
2933 * @page: page to charge
2934 * @gfp: reclaim mode
2935 * @order: allocation order
2936 * @memcg: memory cgroup to charge
2938 * Returns 0 on success, an error code on failure.
2940 int __memcg_kmem_charge_memcg(struct page
*page
, gfp_t gfp
, int order
,
2941 struct mem_cgroup
*memcg
)
2943 unsigned int nr_pages
= 1 << order
;
2944 struct page_counter
*counter
;
2947 ret
= try_charge(memcg
, gfp
, nr_pages
);
2951 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2952 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2953 cancel_charge(memcg
, nr_pages
);
2960 * __memcg_kmem_charge: charge a kmem page to the current memory cgroup
2961 * @page: page to charge
2962 * @gfp: reclaim mode
2963 * @order: allocation order
2965 * Returns 0 on success, an error code on failure.
2967 int __memcg_kmem_charge(struct page
*page
, gfp_t gfp
, int order
)
2969 struct mem_cgroup
*memcg
;
2972 if (memcg_kmem_bypass())
2975 memcg
= get_mem_cgroup_from_current();
2976 if (!mem_cgroup_is_root(memcg
)) {
2977 ret
= __memcg_kmem_charge_memcg(page
, gfp
, order
, memcg
);
2979 page
->mem_cgroup
= memcg
;
2980 __SetPageKmemcg(page
);
2983 css_put(&memcg
->css
);
2988 * __memcg_kmem_uncharge_memcg: uncharge a kmem page
2989 * @memcg: memcg to uncharge
2990 * @nr_pages: number of pages to uncharge
2992 void __memcg_kmem_uncharge_memcg(struct mem_cgroup
*memcg
,
2993 unsigned int nr_pages
)
2995 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2996 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2998 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2999 if (do_memsw_account())
3000 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
3003 * __memcg_kmem_uncharge: uncharge a kmem page
3004 * @page: page to uncharge
3005 * @order: allocation order
3007 void __memcg_kmem_uncharge(struct page
*page
, int order
)
3009 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
3010 unsigned int nr_pages
= 1 << order
;
3015 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
3016 __memcg_kmem_uncharge_memcg(memcg
, nr_pages
);
3017 page
->mem_cgroup
= NULL
;
3019 /* slab pages do not have PageKmemcg flag set */
3020 if (PageKmemcg(page
))
3021 __ClearPageKmemcg(page
);
3023 css_put_many(&memcg
->css
, nr_pages
);
3025 #endif /* CONFIG_MEMCG_KMEM */
3027 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3030 * Because tail pages are not marked as "used", set it. We're under
3031 * pgdat->lru_lock and migration entries setup in all page mappings.
3033 void mem_cgroup_split_huge_fixup(struct page
*head
)
3037 if (mem_cgroup_disabled())
3040 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
3041 head
[i
].mem_cgroup
= head
->mem_cgroup
;
3043 __mod_memcg_state(head
->mem_cgroup
, MEMCG_RSS_HUGE
, -HPAGE_PMD_NR
);
3045 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3047 #ifdef CONFIG_MEMCG_SWAP
3049 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3050 * @entry: swap entry to be moved
3051 * @from: mem_cgroup which the entry is moved from
3052 * @to: mem_cgroup which the entry is moved to
3054 * It succeeds only when the swap_cgroup's record for this entry is the same
3055 * as the mem_cgroup's id of @from.
3057 * Returns 0 on success, -EINVAL on failure.
3059 * The caller must have charged to @to, IOW, called page_counter_charge() about
3060 * both res and memsw, and called css_get().
3062 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3063 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3065 unsigned short old_id
, new_id
;
3067 old_id
= mem_cgroup_id(from
);
3068 new_id
= mem_cgroup_id(to
);
3070 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3071 mod_memcg_state(from
, MEMCG_SWAP
, -1);
3072 mod_memcg_state(to
, MEMCG_SWAP
, 1);
3078 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3079 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3085 static DEFINE_MUTEX(memcg_max_mutex
);
3087 static int mem_cgroup_resize_max(struct mem_cgroup
*memcg
,
3088 unsigned long max
, bool memsw
)
3090 bool enlarge
= false;
3091 bool drained
= false;
3093 bool limits_invariant
;
3094 struct page_counter
*counter
= memsw
? &memcg
->memsw
: &memcg
->memory
;
3097 if (signal_pending(current
)) {
3102 mutex_lock(&memcg_max_mutex
);
3104 * Make sure that the new limit (memsw or memory limit) doesn't
3105 * break our basic invariant rule memory.max <= memsw.max.
3107 limits_invariant
= memsw
? max
>= memcg
->memory
.max
:
3108 max
<= memcg
->memsw
.max
;
3109 if (!limits_invariant
) {
3110 mutex_unlock(&memcg_max_mutex
);
3114 if (max
> counter
->max
)
3116 ret
= page_counter_set_max(counter
, max
);
3117 mutex_unlock(&memcg_max_mutex
);
3123 drain_all_stock(memcg
);
3128 if (!try_to_free_mem_cgroup_pages(memcg
, 1,
3129 GFP_KERNEL
, !memsw
)) {
3135 if (!ret
&& enlarge
)
3136 memcg_oom_recover(memcg
);
3141 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
3143 unsigned long *total_scanned
)
3145 unsigned long nr_reclaimed
= 0;
3146 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
3147 unsigned long reclaimed
;
3149 struct mem_cgroup_tree_per_node
*mctz
;
3150 unsigned long excess
;
3151 unsigned long nr_scanned
;
3156 mctz
= soft_limit_tree_node(pgdat
->node_id
);
3159 * Do not even bother to check the largest node if the root
3160 * is empty. Do it lockless to prevent lock bouncing. Races
3161 * are acceptable as soft limit is best effort anyway.
3163 if (!mctz
|| RB_EMPTY_ROOT(&mctz
->rb_root
))
3167 * This loop can run a while, specially if mem_cgroup's continuously
3168 * keep exceeding their soft limit and putting the system under
3175 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3180 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
3181 gfp_mask
, &nr_scanned
);
3182 nr_reclaimed
+= reclaimed
;
3183 *total_scanned
+= nr_scanned
;
3184 spin_lock_irq(&mctz
->lock
);
3185 __mem_cgroup_remove_exceeded(mz
, mctz
);
3188 * If we failed to reclaim anything from this memory cgroup
3189 * it is time to move on to the next cgroup
3193 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
3195 excess
= soft_limit_excess(mz
->memcg
);
3197 * One school of thought says that we should not add
3198 * back the node to the tree if reclaim returns 0.
3199 * But our reclaim could return 0, simply because due
3200 * to priority we are exposing a smaller subset of
3201 * memory to reclaim from. Consider this as a longer
3204 /* If excess == 0, no tree ops */
3205 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
3206 spin_unlock_irq(&mctz
->lock
);
3207 css_put(&mz
->memcg
->css
);
3210 * Could not reclaim anything and there are no more
3211 * mem cgroups to try or we seem to be looping without
3212 * reclaiming anything.
3214 if (!nr_reclaimed
&&
3216 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3218 } while (!nr_reclaimed
);
3220 css_put(&next_mz
->memcg
->css
);
3221 return nr_reclaimed
;
3225 * Test whether @memcg has children, dead or alive. Note that this
3226 * function doesn't care whether @memcg has use_hierarchy enabled and
3227 * returns %true if there are child csses according to the cgroup
3228 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
3230 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
3235 ret
= css_next_child(NULL
, &memcg
->css
);
3241 * Reclaims as many pages from the given memcg as possible.
3243 * Caller is responsible for holding css reference for memcg.
3245 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3247 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
3249 /* we call try-to-free pages for make this cgroup empty */
3250 lru_add_drain_all();
3252 drain_all_stock(memcg
);
3254 /* try to free all pages in this cgroup */
3255 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
3258 if (signal_pending(current
))
3261 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
3265 /* maybe some writeback is necessary */
3266 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3274 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
3275 char *buf
, size_t nbytes
,
3278 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3280 if (mem_cgroup_is_root(memcg
))
3282 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
3285 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
3288 return mem_cgroup_from_css(css
)->use_hierarchy
;
3291 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
3292 struct cftype
*cft
, u64 val
)
3295 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3296 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
3298 if (memcg
->use_hierarchy
== val
)
3302 * If parent's use_hierarchy is set, we can't make any modifications
3303 * in the child subtrees. If it is unset, then the change can
3304 * occur, provided the current cgroup has no children.
3306 * For the root cgroup, parent_mem is NULL, we allow value to be
3307 * set if there are no children.
3309 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
3310 (val
== 1 || val
== 0)) {
3311 if (!memcg_has_children(memcg
))
3312 memcg
->use_hierarchy
= val
;
3321 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3325 if (mem_cgroup_is_root(memcg
)) {
3326 val
= memcg_page_state(memcg
, MEMCG_CACHE
) +
3327 memcg_page_state(memcg
, MEMCG_RSS
);
3329 val
+= memcg_page_state(memcg
, MEMCG_SWAP
);
3332 val
= page_counter_read(&memcg
->memory
);
3334 val
= page_counter_read(&memcg
->memsw
);
3347 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
3350 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3351 struct page_counter
*counter
;
3353 switch (MEMFILE_TYPE(cft
->private)) {
3355 counter
= &memcg
->memory
;
3358 counter
= &memcg
->memsw
;
3361 counter
= &memcg
->kmem
;
3364 counter
= &memcg
->tcpmem
;
3370 switch (MEMFILE_ATTR(cft
->private)) {
3372 if (counter
== &memcg
->memory
)
3373 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
3374 if (counter
== &memcg
->memsw
)
3375 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
3376 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
3378 return (u64
)counter
->max
* PAGE_SIZE
;
3380 return (u64
)counter
->watermark
* PAGE_SIZE
;
3382 return counter
->failcnt
;
3383 case RES_SOFT_LIMIT
:
3384 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
3390 static void memcg_flush_percpu_vmstats(struct mem_cgroup
*memcg
, bool slab_only
)
3392 unsigned long stat
[MEMCG_NR_STAT
];
3393 struct mem_cgroup
*mi
;
3395 int min_idx
, max_idx
;
3398 min_idx
= NR_SLAB_RECLAIMABLE
;
3399 max_idx
= NR_SLAB_UNRECLAIMABLE
;
3402 max_idx
= MEMCG_NR_STAT
;
3405 for (i
= min_idx
; i
< max_idx
; i
++)
3408 for_each_online_cpu(cpu
)
3409 for (i
= min_idx
; i
< max_idx
; i
++)
3410 stat
[i
] += per_cpu(memcg
->vmstats_percpu
->stat
[i
], cpu
);
3412 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
3413 for (i
= min_idx
; i
< max_idx
; i
++)
3414 atomic_long_add(stat
[i
], &mi
->vmstats
[i
]);
3417 max_idx
= NR_VM_NODE_STAT_ITEMS
;
3419 for_each_node(node
) {
3420 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
3421 struct mem_cgroup_per_node
*pi
;
3423 for (i
= min_idx
; i
< max_idx
; i
++)
3426 for_each_online_cpu(cpu
)
3427 for (i
= min_idx
; i
< max_idx
; i
++)
3429 pn
->lruvec_stat_cpu
->count
[i
], cpu
);
3431 for (pi
= pn
; pi
; pi
= parent_nodeinfo(pi
, node
))
3432 for (i
= min_idx
; i
< max_idx
; i
++)
3433 atomic_long_add(stat
[i
], &pi
->lruvec_stat
[i
]);
3437 static void memcg_flush_percpu_vmevents(struct mem_cgroup
*memcg
)
3439 unsigned long events
[NR_VM_EVENT_ITEMS
];
3440 struct mem_cgroup
*mi
;
3443 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3446 for_each_online_cpu(cpu
)
3447 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3448 events
[i
] += per_cpu(memcg
->vmstats_percpu
->events
[i
],
3451 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
3452 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3453 atomic_long_add(events
[i
], &mi
->vmevents
[i
]);
3456 #ifdef CONFIG_MEMCG_KMEM
3457 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3461 if (cgroup_memory_nokmem
)
3464 BUG_ON(memcg
->kmemcg_id
>= 0);
3465 BUG_ON(memcg
->kmem_state
);
3467 memcg_id
= memcg_alloc_cache_id();
3471 static_branch_inc(&memcg_kmem_enabled_key
);
3473 * A memory cgroup is considered kmem-online as soon as it gets
3474 * kmemcg_id. Setting the id after enabling static branching will
3475 * guarantee no one starts accounting before all call sites are
3478 memcg
->kmemcg_id
= memcg_id
;
3479 memcg
->kmem_state
= KMEM_ONLINE
;
3480 INIT_LIST_HEAD(&memcg
->kmem_caches
);
3485 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3487 struct cgroup_subsys_state
*css
;
3488 struct mem_cgroup
*parent
, *child
;
3491 if (memcg
->kmem_state
!= KMEM_ONLINE
)
3494 * Clear the online state before clearing memcg_caches array
3495 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
3496 * guarantees that no cache will be created for this cgroup
3497 * after we are done (see memcg_create_kmem_cache()).
3499 memcg
->kmem_state
= KMEM_ALLOCATED
;
3501 parent
= parent_mem_cgroup(memcg
);
3503 parent
= root_mem_cgroup
;
3506 * Deactivate and reparent kmem_caches. Then flush percpu
3507 * slab statistics to have precise values at the parent and
3508 * all ancestor levels. It's required to keep slab stats
3509 * accurate after the reparenting of kmem_caches.
3511 memcg_deactivate_kmem_caches(memcg
, parent
);
3512 memcg_flush_percpu_vmstats(memcg
, true);
3514 kmemcg_id
= memcg
->kmemcg_id
;
3515 BUG_ON(kmemcg_id
< 0);
3518 * Change kmemcg_id of this cgroup and all its descendants to the
3519 * parent's id, and then move all entries from this cgroup's list_lrus
3520 * to ones of the parent. After we have finished, all list_lrus
3521 * corresponding to this cgroup are guaranteed to remain empty. The
3522 * ordering is imposed by list_lru_node->lock taken by
3523 * memcg_drain_all_list_lrus().
3525 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3526 css_for_each_descendant_pre(css
, &memcg
->css
) {
3527 child
= mem_cgroup_from_css(css
);
3528 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
3529 child
->kmemcg_id
= parent
->kmemcg_id
;
3530 if (!memcg
->use_hierarchy
)
3535 memcg_drain_all_list_lrus(kmemcg_id
, parent
);
3537 memcg_free_cache_id(kmemcg_id
);
3540 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3542 /* css_alloc() failed, offlining didn't happen */
3543 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
3544 memcg_offline_kmem(memcg
);
3546 if (memcg
->kmem_state
== KMEM_ALLOCATED
) {
3547 WARN_ON(!list_empty(&memcg
->kmem_caches
));
3548 static_branch_dec(&memcg_kmem_enabled_key
);
3552 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3556 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3559 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3562 #endif /* CONFIG_MEMCG_KMEM */
3564 static int memcg_update_kmem_max(struct mem_cgroup
*memcg
,
3569 mutex_lock(&memcg_max_mutex
);
3570 ret
= page_counter_set_max(&memcg
->kmem
, max
);
3571 mutex_unlock(&memcg_max_mutex
);
3575 static int memcg_update_tcp_max(struct mem_cgroup
*memcg
, unsigned long max
)
3579 mutex_lock(&memcg_max_mutex
);
3581 ret
= page_counter_set_max(&memcg
->tcpmem
, max
);
3585 if (!memcg
->tcpmem_active
) {
3587 * The active flag needs to be written after the static_key
3588 * update. This is what guarantees that the socket activation
3589 * function is the last one to run. See mem_cgroup_sk_alloc()
3590 * for details, and note that we don't mark any socket as
3591 * belonging to this memcg until that flag is up.
3593 * We need to do this, because static_keys will span multiple
3594 * sites, but we can't control their order. If we mark a socket
3595 * as accounted, but the accounting functions are not patched in
3596 * yet, we'll lose accounting.
3598 * We never race with the readers in mem_cgroup_sk_alloc(),
3599 * because when this value change, the code to process it is not
3602 static_branch_inc(&memcg_sockets_enabled_key
);
3603 memcg
->tcpmem_active
= true;
3606 mutex_unlock(&memcg_max_mutex
);
3611 * The user of this function is...
3614 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
3615 char *buf
, size_t nbytes
, loff_t off
)
3617 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3618 unsigned long nr_pages
;
3621 buf
= strstrip(buf
);
3622 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
3626 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3628 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3632 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3634 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, false);
3637 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, true);
3640 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3641 "Please report your usecase to linux-mm@kvack.org if you "
3642 "depend on this functionality.\n");
3643 ret
= memcg_update_kmem_max(memcg
, nr_pages
);
3646 ret
= memcg_update_tcp_max(memcg
, nr_pages
);
3650 case RES_SOFT_LIMIT
:
3651 memcg
->soft_limit
= nr_pages
;
3655 return ret
?: nbytes
;
3658 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3659 size_t nbytes
, loff_t off
)
3661 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3662 struct page_counter
*counter
;
3664 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3666 counter
= &memcg
->memory
;
3669 counter
= &memcg
->memsw
;
3672 counter
= &memcg
->kmem
;
3675 counter
= &memcg
->tcpmem
;
3681 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3683 page_counter_reset_watermark(counter
);
3686 counter
->failcnt
= 0;
3695 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3698 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3702 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3703 struct cftype
*cft
, u64 val
)
3705 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3707 if (val
& ~MOVE_MASK
)
3711 * No kind of locking is needed in here, because ->can_attach() will
3712 * check this value once in the beginning of the process, and then carry
3713 * on with stale data. This means that changes to this value will only
3714 * affect task migrations starting after the change.
3716 memcg
->move_charge_at_immigrate
= val
;
3720 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3721 struct cftype
*cft
, u64 val
)
3729 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3730 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3731 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3733 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
3734 int nid
, unsigned int lru_mask
)
3736 struct lruvec
*lruvec
= mem_cgroup_lruvec(NODE_DATA(nid
), memcg
);
3737 unsigned long nr
= 0;
3740 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
3743 if (!(BIT(lru
) & lru_mask
))
3745 nr
+= lruvec_page_state_local(lruvec
, NR_LRU_BASE
+ lru
);
3750 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
3751 unsigned int lru_mask
)
3753 unsigned long nr
= 0;
3757 if (!(BIT(lru
) & lru_mask
))
3759 nr
+= memcg_page_state_local(memcg
, NR_LRU_BASE
+ lru
);
3764 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3768 unsigned int lru_mask
;
3771 static const struct numa_stat stats
[] = {
3772 { "total", LRU_ALL
},
3773 { "file", LRU_ALL_FILE
},
3774 { "anon", LRU_ALL_ANON
},
3775 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3777 const struct numa_stat
*stat
;
3780 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3782 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3783 nr
= mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
);
3784 seq_printf(m
, "%s=%lu", stat
->name
, nr
);
3785 for_each_node_state(nid
, N_MEMORY
) {
3786 nr
= mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3788 seq_printf(m
, " N%d=%lu", nid
, nr
);
3793 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3794 struct mem_cgroup
*iter
;
3797 for_each_mem_cgroup_tree(iter
, memcg
)
3798 nr
+= mem_cgroup_nr_lru_pages(iter
, stat
->lru_mask
);
3799 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
, nr
);
3800 for_each_node_state(nid
, N_MEMORY
) {
3802 for_each_mem_cgroup_tree(iter
, memcg
)
3803 nr
+= mem_cgroup_node_nr_lru_pages(
3804 iter
, nid
, stat
->lru_mask
);
3805 seq_printf(m
, " N%d=%lu", nid
, nr
);
3812 #endif /* CONFIG_NUMA */
3814 static const unsigned int memcg1_stats
[] = {
3825 static const char *const memcg1_stat_names
[] = {
3836 /* Universal VM events cgroup1 shows, original sort order */
3837 static const unsigned int memcg1_events
[] = {
3844 static const char *const memcg1_event_names
[] = {
3851 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3853 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3854 unsigned long memory
, memsw
;
3855 struct mem_cgroup
*mi
;
3858 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names
) != ARRAY_SIZE(memcg1_stats
));
3859 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names
) != NR_LRU_LISTS
);
3861 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3862 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3864 seq_printf(m
, "%s %lu\n", memcg1_stat_names
[i
],
3865 memcg_page_state_local(memcg
, memcg1_stats
[i
]) *
3869 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3870 seq_printf(m
, "%s %lu\n", memcg1_event_names
[i
],
3871 memcg_events_local(memcg
, memcg1_events
[i
]));
3873 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3874 seq_printf(m
, "%s %lu\n", mem_cgroup_lru_names
[i
],
3875 memcg_page_state_local(memcg
, NR_LRU_BASE
+ i
) *
3878 /* Hierarchical information */
3879 memory
= memsw
= PAGE_COUNTER_MAX
;
3880 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3881 memory
= min(memory
, mi
->memory
.max
);
3882 memsw
= min(memsw
, mi
->memsw
.max
);
3884 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3885 (u64
)memory
* PAGE_SIZE
);
3886 if (do_memsw_account())
3887 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3888 (u64
)memsw
* PAGE_SIZE
);
3890 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3891 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3893 seq_printf(m
, "total_%s %llu\n", memcg1_stat_names
[i
],
3894 (u64
)memcg_page_state(memcg
, memcg1_stats
[i
]) *
3898 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3899 seq_printf(m
, "total_%s %llu\n", memcg1_event_names
[i
],
3900 (u64
)memcg_events(memcg
, memcg1_events
[i
]));
3902 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3903 seq_printf(m
, "total_%s %llu\n", mem_cgroup_lru_names
[i
],
3904 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
3907 #ifdef CONFIG_DEBUG_VM
3910 struct mem_cgroup_per_node
*mz
;
3911 struct zone_reclaim_stat
*rstat
;
3912 unsigned long recent_rotated
[2] = {0, 0};
3913 unsigned long recent_scanned
[2] = {0, 0};
3915 for_each_online_pgdat(pgdat
) {
3916 mz
= mem_cgroup_nodeinfo(memcg
, pgdat
->node_id
);
3917 rstat
= &mz
->lruvec
.reclaim_stat
;
3919 recent_rotated
[0] += rstat
->recent_rotated
[0];
3920 recent_rotated
[1] += rstat
->recent_rotated
[1];
3921 recent_scanned
[0] += rstat
->recent_scanned
[0];
3922 recent_scanned
[1] += rstat
->recent_scanned
[1];
3924 seq_printf(m
, "recent_rotated_anon %lu\n", recent_rotated
[0]);
3925 seq_printf(m
, "recent_rotated_file %lu\n", recent_rotated
[1]);
3926 seq_printf(m
, "recent_scanned_anon %lu\n", recent_scanned
[0]);
3927 seq_printf(m
, "recent_scanned_file %lu\n", recent_scanned
[1]);
3934 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3937 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3939 return mem_cgroup_swappiness(memcg
);
3942 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3943 struct cftype
*cft
, u64 val
)
3945 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3951 memcg
->swappiness
= val
;
3953 vm_swappiness
= val
;
3958 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3960 struct mem_cgroup_threshold_ary
*t
;
3961 unsigned long usage
;
3966 t
= rcu_dereference(memcg
->thresholds
.primary
);
3968 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3973 usage
= mem_cgroup_usage(memcg
, swap
);
3976 * current_threshold points to threshold just below or equal to usage.
3977 * If it's not true, a threshold was crossed after last
3978 * call of __mem_cgroup_threshold().
3980 i
= t
->current_threshold
;
3983 * Iterate backward over array of thresholds starting from
3984 * current_threshold and check if a threshold is crossed.
3985 * If none of thresholds below usage is crossed, we read
3986 * only one element of the array here.
3988 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3989 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3991 /* i = current_threshold + 1 */
3995 * Iterate forward over array of thresholds starting from
3996 * current_threshold+1 and check if a threshold is crossed.
3997 * If none of thresholds above usage is crossed, we read
3998 * only one element of the array here.
4000 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
4001 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4003 /* Update current_threshold */
4004 t
->current_threshold
= i
- 1;
4009 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
4012 __mem_cgroup_threshold(memcg
, false);
4013 if (do_memsw_account())
4014 __mem_cgroup_threshold(memcg
, true);
4016 memcg
= parent_mem_cgroup(memcg
);
4020 static int compare_thresholds(const void *a
, const void *b
)
4022 const struct mem_cgroup_threshold
*_a
= a
;
4023 const struct mem_cgroup_threshold
*_b
= b
;
4025 if (_a
->threshold
> _b
->threshold
)
4028 if (_a
->threshold
< _b
->threshold
)
4034 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
4036 struct mem_cgroup_eventfd_list
*ev
;
4038 spin_lock(&memcg_oom_lock
);
4040 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
4041 eventfd_signal(ev
->eventfd
, 1);
4043 spin_unlock(&memcg_oom_lock
);
4047 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
4049 struct mem_cgroup
*iter
;
4051 for_each_mem_cgroup_tree(iter
, memcg
)
4052 mem_cgroup_oom_notify_cb(iter
);
4055 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4056 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
4058 struct mem_cgroup_thresholds
*thresholds
;
4059 struct mem_cgroup_threshold_ary
*new;
4060 unsigned long threshold
;
4061 unsigned long usage
;
4064 ret
= page_counter_memparse(args
, "-1", &threshold
);
4068 mutex_lock(&memcg
->thresholds_lock
);
4071 thresholds
= &memcg
->thresholds
;
4072 usage
= mem_cgroup_usage(memcg
, false);
4073 } else if (type
== _MEMSWAP
) {
4074 thresholds
= &memcg
->memsw_thresholds
;
4075 usage
= mem_cgroup_usage(memcg
, true);
4079 /* Check if a threshold crossed before adding a new one */
4080 if (thresholds
->primary
)
4081 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4083 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4085 /* Allocate memory for new array of thresholds */
4086 new = kmalloc(struct_size(new, entries
, size
), GFP_KERNEL
);
4093 /* Copy thresholds (if any) to new array */
4094 if (thresholds
->primary
) {
4095 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
4096 sizeof(struct mem_cgroup_threshold
));
4099 /* Add new threshold */
4100 new->entries
[size
- 1].eventfd
= eventfd
;
4101 new->entries
[size
- 1].threshold
= threshold
;
4103 /* Sort thresholds. Registering of new threshold isn't time-critical */
4104 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
4105 compare_thresholds
, NULL
);
4107 /* Find current threshold */
4108 new->current_threshold
= -1;
4109 for (i
= 0; i
< size
; i
++) {
4110 if (new->entries
[i
].threshold
<= usage
) {
4112 * new->current_threshold will not be used until
4113 * rcu_assign_pointer(), so it's safe to increment
4116 ++new->current_threshold
;
4121 /* Free old spare buffer and save old primary buffer as spare */
4122 kfree(thresholds
->spare
);
4123 thresholds
->spare
= thresholds
->primary
;
4125 rcu_assign_pointer(thresholds
->primary
, new);
4127 /* To be sure that nobody uses thresholds */
4131 mutex_unlock(&memcg
->thresholds_lock
);
4136 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4137 struct eventfd_ctx
*eventfd
, const char *args
)
4139 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
4142 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4143 struct eventfd_ctx
*eventfd
, const char *args
)
4145 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
4148 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4149 struct eventfd_ctx
*eventfd
, enum res_type type
)
4151 struct mem_cgroup_thresholds
*thresholds
;
4152 struct mem_cgroup_threshold_ary
*new;
4153 unsigned long usage
;
4156 mutex_lock(&memcg
->thresholds_lock
);
4159 thresholds
= &memcg
->thresholds
;
4160 usage
= mem_cgroup_usage(memcg
, false);
4161 } else if (type
== _MEMSWAP
) {
4162 thresholds
= &memcg
->memsw_thresholds
;
4163 usage
= mem_cgroup_usage(memcg
, true);
4167 if (!thresholds
->primary
)
4170 /* Check if a threshold crossed before removing */
4171 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4173 /* Calculate new number of threshold */
4175 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4176 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4180 new = thresholds
->spare
;
4182 /* Set thresholds array to NULL if we don't have thresholds */
4191 /* Copy thresholds and find current threshold */
4192 new->current_threshold
= -1;
4193 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4194 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4197 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4198 if (new->entries
[j
].threshold
<= usage
) {
4200 * new->current_threshold will not be used
4201 * until rcu_assign_pointer(), so it's safe to increment
4204 ++new->current_threshold
;
4210 /* Swap primary and spare array */
4211 thresholds
->spare
= thresholds
->primary
;
4213 rcu_assign_pointer(thresholds
->primary
, new);
4215 /* To be sure that nobody uses thresholds */
4218 /* If all events are unregistered, free the spare array */
4220 kfree(thresholds
->spare
);
4221 thresholds
->spare
= NULL
;
4224 mutex_unlock(&memcg
->thresholds_lock
);
4227 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4228 struct eventfd_ctx
*eventfd
)
4230 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
4233 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4234 struct eventfd_ctx
*eventfd
)
4236 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
4239 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
4240 struct eventfd_ctx
*eventfd
, const char *args
)
4242 struct mem_cgroup_eventfd_list
*event
;
4244 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4248 spin_lock(&memcg_oom_lock
);
4250 event
->eventfd
= eventfd
;
4251 list_add(&event
->list
, &memcg
->oom_notify
);
4253 /* already in OOM ? */
4254 if (memcg
->under_oom
)
4255 eventfd_signal(eventfd
, 1);
4256 spin_unlock(&memcg_oom_lock
);
4261 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
4262 struct eventfd_ctx
*eventfd
)
4264 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4266 spin_lock(&memcg_oom_lock
);
4268 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4269 if (ev
->eventfd
== eventfd
) {
4270 list_del(&ev
->list
);
4275 spin_unlock(&memcg_oom_lock
);
4278 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
4280 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(sf
);
4282 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
4283 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
4284 seq_printf(sf
, "oom_kill %lu\n",
4285 atomic_long_read(&memcg
->memory_events
[MEMCG_OOM_KILL
]));
4289 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
4290 struct cftype
*cft
, u64 val
)
4292 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4294 /* cannot set to root cgroup and only 0 and 1 are allowed */
4295 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
4298 memcg
->oom_kill_disable
= val
;
4300 memcg_oom_recover(memcg
);
4305 #ifdef CONFIG_CGROUP_WRITEBACK
4307 #include <trace/events/writeback.h>
4309 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4311 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
4314 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4316 wb_domain_exit(&memcg
->cgwb_domain
);
4319 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4321 wb_domain_size_changed(&memcg
->cgwb_domain
);
4324 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
4326 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4328 if (!memcg
->css
.parent
)
4331 return &memcg
->cgwb_domain
;
4335 * idx can be of type enum memcg_stat_item or node_stat_item.
4336 * Keep in sync with memcg_exact_page().
4338 static unsigned long memcg_exact_page_state(struct mem_cgroup
*memcg
, int idx
)
4340 long x
= atomic_long_read(&memcg
->vmstats
[idx
]);
4343 for_each_online_cpu(cpu
)
4344 x
+= per_cpu_ptr(memcg
->vmstats_percpu
, cpu
)->stat
[idx
];
4351 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4352 * @wb: bdi_writeback in question
4353 * @pfilepages: out parameter for number of file pages
4354 * @pheadroom: out parameter for number of allocatable pages according to memcg
4355 * @pdirty: out parameter for number of dirty pages
4356 * @pwriteback: out parameter for number of pages under writeback
4358 * Determine the numbers of file, headroom, dirty, and writeback pages in
4359 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4360 * is a bit more involved.
4362 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4363 * headroom is calculated as the lowest headroom of itself and the
4364 * ancestors. Note that this doesn't consider the actual amount of
4365 * available memory in the system. The caller should further cap
4366 * *@pheadroom accordingly.
4368 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
4369 unsigned long *pheadroom
, unsigned long *pdirty
,
4370 unsigned long *pwriteback
)
4372 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4373 struct mem_cgroup
*parent
;
4375 *pdirty
= memcg_exact_page_state(memcg
, NR_FILE_DIRTY
);
4377 /* this should eventually include NR_UNSTABLE_NFS */
4378 *pwriteback
= memcg_exact_page_state(memcg
, NR_WRITEBACK
);
4379 *pfilepages
= memcg_exact_page_state(memcg
, NR_INACTIVE_FILE
) +
4380 memcg_exact_page_state(memcg
, NR_ACTIVE_FILE
);
4381 *pheadroom
= PAGE_COUNTER_MAX
;
4383 while ((parent
= parent_mem_cgroup(memcg
))) {
4384 unsigned long ceiling
= min(memcg
->memory
.max
, memcg
->high
);
4385 unsigned long used
= page_counter_read(&memcg
->memory
);
4387 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
4393 * Foreign dirty flushing
4395 * There's an inherent mismatch between memcg and writeback. The former
4396 * trackes ownership per-page while the latter per-inode. This was a
4397 * deliberate design decision because honoring per-page ownership in the
4398 * writeback path is complicated, may lead to higher CPU and IO overheads
4399 * and deemed unnecessary given that write-sharing an inode across
4400 * different cgroups isn't a common use-case.
4402 * Combined with inode majority-writer ownership switching, this works well
4403 * enough in most cases but there are some pathological cases. For
4404 * example, let's say there are two cgroups A and B which keep writing to
4405 * different but confined parts of the same inode. B owns the inode and
4406 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4407 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4408 * triggering background writeback. A will be slowed down without a way to
4409 * make writeback of the dirty pages happen.
4411 * Conditions like the above can lead to a cgroup getting repatedly and
4412 * severely throttled after making some progress after each
4413 * dirty_expire_interval while the underyling IO device is almost
4416 * Solving this problem completely requires matching the ownership tracking
4417 * granularities between memcg and writeback in either direction. However,
4418 * the more egregious behaviors can be avoided by simply remembering the
4419 * most recent foreign dirtying events and initiating remote flushes on
4420 * them when local writeback isn't enough to keep the memory clean enough.
4422 * The following two functions implement such mechanism. When a foreign
4423 * page - a page whose memcg and writeback ownerships don't match - is
4424 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4425 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4426 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4427 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4428 * foreign bdi_writebacks which haven't expired. Both the numbers of
4429 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4430 * limited to MEMCG_CGWB_FRN_CNT.
4432 * The mechanism only remembers IDs and doesn't hold any object references.
4433 * As being wrong occasionally doesn't matter, updates and accesses to the
4434 * records are lockless and racy.
4436 void mem_cgroup_track_foreign_dirty_slowpath(struct page
*page
,
4437 struct bdi_writeback
*wb
)
4439 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
4440 struct memcg_cgwb_frn
*frn
;
4441 u64 now
= get_jiffies_64();
4442 u64 oldest_at
= now
;
4446 trace_track_foreign_dirty(page
, wb
);
4449 * Pick the slot to use. If there is already a slot for @wb, keep
4450 * using it. If not replace the oldest one which isn't being
4453 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4454 frn
= &memcg
->cgwb_frn
[i
];
4455 if (frn
->bdi_id
== wb
->bdi
->id
&&
4456 frn
->memcg_id
== wb
->memcg_css
->id
)
4458 if (time_before64(frn
->at
, oldest_at
) &&
4459 atomic_read(&frn
->done
.cnt
) == 1) {
4461 oldest_at
= frn
->at
;
4465 if (i
< MEMCG_CGWB_FRN_CNT
) {
4467 * Re-using an existing one. Update timestamp lazily to
4468 * avoid making the cacheline hot. We want them to be
4469 * reasonably up-to-date and significantly shorter than
4470 * dirty_expire_interval as that's what expires the record.
4471 * Use the shorter of 1s and dirty_expire_interval / 8.
4473 unsigned long update_intv
=
4474 min_t(unsigned long, HZ
,
4475 msecs_to_jiffies(dirty_expire_interval
* 10) / 8);
4477 if (time_before64(frn
->at
, now
- update_intv
))
4479 } else if (oldest
>= 0) {
4480 /* replace the oldest free one */
4481 frn
= &memcg
->cgwb_frn
[oldest
];
4482 frn
->bdi_id
= wb
->bdi
->id
;
4483 frn
->memcg_id
= wb
->memcg_css
->id
;
4488 /* issue foreign writeback flushes for recorded foreign dirtying events */
4489 void mem_cgroup_flush_foreign(struct bdi_writeback
*wb
)
4491 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4492 unsigned long intv
= msecs_to_jiffies(dirty_expire_interval
* 10);
4493 u64 now
= jiffies_64
;
4496 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4497 struct memcg_cgwb_frn
*frn
= &memcg
->cgwb_frn
[i
];
4500 * If the record is older than dirty_expire_interval,
4501 * writeback on it has already started. No need to kick it
4502 * off again. Also, don't start a new one if there's
4503 * already one in flight.
4505 if (time_after64(frn
->at
, now
- intv
) &&
4506 atomic_read(&frn
->done
.cnt
) == 1) {
4508 trace_flush_foreign(wb
, frn
->bdi_id
, frn
->memcg_id
);
4509 cgroup_writeback_by_id(frn
->bdi_id
, frn
->memcg_id
, 0,
4510 WB_REASON_FOREIGN_FLUSH
,
4516 #else /* CONFIG_CGROUP_WRITEBACK */
4518 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4523 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4527 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4531 #endif /* CONFIG_CGROUP_WRITEBACK */
4534 * DO NOT USE IN NEW FILES.
4536 * "cgroup.event_control" implementation.
4538 * This is way over-engineered. It tries to support fully configurable
4539 * events for each user. Such level of flexibility is completely
4540 * unnecessary especially in the light of the planned unified hierarchy.
4542 * Please deprecate this and replace with something simpler if at all
4547 * Unregister event and free resources.
4549 * Gets called from workqueue.
4551 static void memcg_event_remove(struct work_struct
*work
)
4553 struct mem_cgroup_event
*event
=
4554 container_of(work
, struct mem_cgroup_event
, remove
);
4555 struct mem_cgroup
*memcg
= event
->memcg
;
4557 remove_wait_queue(event
->wqh
, &event
->wait
);
4559 event
->unregister_event(memcg
, event
->eventfd
);
4561 /* Notify userspace the event is going away. */
4562 eventfd_signal(event
->eventfd
, 1);
4564 eventfd_ctx_put(event
->eventfd
);
4566 css_put(&memcg
->css
);
4570 * Gets called on EPOLLHUP on eventfd when user closes it.
4572 * Called with wqh->lock held and interrupts disabled.
4574 static int memcg_event_wake(wait_queue_entry_t
*wait
, unsigned mode
,
4575 int sync
, void *key
)
4577 struct mem_cgroup_event
*event
=
4578 container_of(wait
, struct mem_cgroup_event
, wait
);
4579 struct mem_cgroup
*memcg
= event
->memcg
;
4580 __poll_t flags
= key_to_poll(key
);
4582 if (flags
& EPOLLHUP
) {
4584 * If the event has been detached at cgroup removal, we
4585 * can simply return knowing the other side will cleanup
4588 * We can't race against event freeing since the other
4589 * side will require wqh->lock via remove_wait_queue(),
4592 spin_lock(&memcg
->event_list_lock
);
4593 if (!list_empty(&event
->list
)) {
4594 list_del_init(&event
->list
);
4596 * We are in atomic context, but cgroup_event_remove()
4597 * may sleep, so we have to call it in workqueue.
4599 schedule_work(&event
->remove
);
4601 spin_unlock(&memcg
->event_list_lock
);
4607 static void memcg_event_ptable_queue_proc(struct file
*file
,
4608 wait_queue_head_t
*wqh
, poll_table
*pt
)
4610 struct mem_cgroup_event
*event
=
4611 container_of(pt
, struct mem_cgroup_event
, pt
);
4614 add_wait_queue(wqh
, &event
->wait
);
4618 * DO NOT USE IN NEW FILES.
4620 * Parse input and register new cgroup event handler.
4622 * Input must be in format '<event_fd> <control_fd> <args>'.
4623 * Interpretation of args is defined by control file implementation.
4625 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
4626 char *buf
, size_t nbytes
, loff_t off
)
4628 struct cgroup_subsys_state
*css
= of_css(of
);
4629 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4630 struct mem_cgroup_event
*event
;
4631 struct cgroup_subsys_state
*cfile_css
;
4632 unsigned int efd
, cfd
;
4639 buf
= strstrip(buf
);
4641 efd
= simple_strtoul(buf
, &endp
, 10);
4646 cfd
= simple_strtoul(buf
, &endp
, 10);
4647 if ((*endp
!= ' ') && (*endp
!= '\0'))
4651 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
4655 event
->memcg
= memcg
;
4656 INIT_LIST_HEAD(&event
->list
);
4657 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
4658 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
4659 INIT_WORK(&event
->remove
, memcg_event_remove
);
4667 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
4668 if (IS_ERR(event
->eventfd
)) {
4669 ret
= PTR_ERR(event
->eventfd
);
4676 goto out_put_eventfd
;
4679 /* the process need read permission on control file */
4680 /* AV: shouldn't we check that it's been opened for read instead? */
4681 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
4686 * Determine the event callbacks and set them in @event. This used
4687 * to be done via struct cftype but cgroup core no longer knows
4688 * about these events. The following is crude but the whole thing
4689 * is for compatibility anyway.
4691 * DO NOT ADD NEW FILES.
4693 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
4695 if (!strcmp(name
, "memory.usage_in_bytes")) {
4696 event
->register_event
= mem_cgroup_usage_register_event
;
4697 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
4698 } else if (!strcmp(name
, "memory.oom_control")) {
4699 event
->register_event
= mem_cgroup_oom_register_event
;
4700 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
4701 } else if (!strcmp(name
, "memory.pressure_level")) {
4702 event
->register_event
= vmpressure_register_event
;
4703 event
->unregister_event
= vmpressure_unregister_event
;
4704 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
4705 event
->register_event
= memsw_cgroup_usage_register_event
;
4706 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
4713 * Verify @cfile should belong to @css. Also, remaining events are
4714 * automatically removed on cgroup destruction but the removal is
4715 * asynchronous, so take an extra ref on @css.
4717 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
4718 &memory_cgrp_subsys
);
4720 if (IS_ERR(cfile_css
))
4722 if (cfile_css
!= css
) {
4727 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
4731 vfs_poll(efile
.file
, &event
->pt
);
4733 spin_lock(&memcg
->event_list_lock
);
4734 list_add(&event
->list
, &memcg
->event_list
);
4735 spin_unlock(&memcg
->event_list_lock
);
4747 eventfd_ctx_put(event
->eventfd
);
4756 static struct cftype mem_cgroup_legacy_files
[] = {
4758 .name
= "usage_in_bytes",
4759 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4760 .read_u64
= mem_cgroup_read_u64
,
4763 .name
= "max_usage_in_bytes",
4764 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4765 .write
= mem_cgroup_reset
,
4766 .read_u64
= mem_cgroup_read_u64
,
4769 .name
= "limit_in_bytes",
4770 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4771 .write
= mem_cgroup_write
,
4772 .read_u64
= mem_cgroup_read_u64
,
4775 .name
= "soft_limit_in_bytes",
4776 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4777 .write
= mem_cgroup_write
,
4778 .read_u64
= mem_cgroup_read_u64
,
4782 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4783 .write
= mem_cgroup_reset
,
4784 .read_u64
= mem_cgroup_read_u64
,
4788 .seq_show
= memcg_stat_show
,
4791 .name
= "force_empty",
4792 .write
= mem_cgroup_force_empty_write
,
4795 .name
= "use_hierarchy",
4796 .write_u64
= mem_cgroup_hierarchy_write
,
4797 .read_u64
= mem_cgroup_hierarchy_read
,
4800 .name
= "cgroup.event_control", /* XXX: for compat */
4801 .write
= memcg_write_event_control
,
4802 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
4805 .name
= "swappiness",
4806 .read_u64
= mem_cgroup_swappiness_read
,
4807 .write_u64
= mem_cgroup_swappiness_write
,
4810 .name
= "move_charge_at_immigrate",
4811 .read_u64
= mem_cgroup_move_charge_read
,
4812 .write_u64
= mem_cgroup_move_charge_write
,
4815 .name
= "oom_control",
4816 .seq_show
= mem_cgroup_oom_control_read
,
4817 .write_u64
= mem_cgroup_oom_control_write
,
4818 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4821 .name
= "pressure_level",
4825 .name
= "numa_stat",
4826 .seq_show
= memcg_numa_stat_show
,
4830 .name
= "kmem.limit_in_bytes",
4831 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4832 .write
= mem_cgroup_write
,
4833 .read_u64
= mem_cgroup_read_u64
,
4836 .name
= "kmem.usage_in_bytes",
4837 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4838 .read_u64
= mem_cgroup_read_u64
,
4841 .name
= "kmem.failcnt",
4842 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
4843 .write
= mem_cgroup_reset
,
4844 .read_u64
= mem_cgroup_read_u64
,
4847 .name
= "kmem.max_usage_in_bytes",
4848 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4849 .write
= mem_cgroup_reset
,
4850 .read_u64
= mem_cgroup_read_u64
,
4852 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
4854 .name
= "kmem.slabinfo",
4855 .seq_start
= memcg_slab_start
,
4856 .seq_next
= memcg_slab_next
,
4857 .seq_stop
= memcg_slab_stop
,
4858 .seq_show
= memcg_slab_show
,
4862 .name
= "kmem.tcp.limit_in_bytes",
4863 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4864 .write
= mem_cgroup_write
,
4865 .read_u64
= mem_cgroup_read_u64
,
4868 .name
= "kmem.tcp.usage_in_bytes",
4869 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4870 .read_u64
= mem_cgroup_read_u64
,
4873 .name
= "kmem.tcp.failcnt",
4874 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4875 .write
= mem_cgroup_reset
,
4876 .read_u64
= mem_cgroup_read_u64
,
4879 .name
= "kmem.tcp.max_usage_in_bytes",
4880 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4881 .write
= mem_cgroup_reset
,
4882 .read_u64
= mem_cgroup_read_u64
,
4884 { }, /* terminate */
4888 * Private memory cgroup IDR
4890 * Swap-out records and page cache shadow entries need to store memcg
4891 * references in constrained space, so we maintain an ID space that is
4892 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4893 * memory-controlled cgroups to 64k.
4895 * However, there usually are many references to the oflline CSS after
4896 * the cgroup has been destroyed, such as page cache or reclaimable
4897 * slab objects, that don't need to hang on to the ID. We want to keep
4898 * those dead CSS from occupying IDs, or we might quickly exhaust the
4899 * relatively small ID space and prevent the creation of new cgroups
4900 * even when there are much fewer than 64k cgroups - possibly none.
4902 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4903 * be freed and recycled when it's no longer needed, which is usually
4904 * when the CSS is offlined.
4906 * The only exception to that are records of swapped out tmpfs/shmem
4907 * pages that need to be attributed to live ancestors on swapin. But
4908 * those references are manageable from userspace.
4911 static DEFINE_IDR(mem_cgroup_idr
);
4913 static void mem_cgroup_id_remove(struct mem_cgroup
*memcg
)
4915 if (memcg
->id
.id
> 0) {
4916 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4921 static void mem_cgroup_id_get_many(struct mem_cgroup
*memcg
, unsigned int n
)
4923 refcount_add(n
, &memcg
->id
.ref
);
4926 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
4928 if (refcount_sub_and_test(n
, &memcg
->id
.ref
)) {
4929 mem_cgroup_id_remove(memcg
);
4931 /* Memcg ID pins CSS */
4932 css_put(&memcg
->css
);
4936 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
4938 mem_cgroup_id_put_many(memcg
, 1);
4942 * mem_cgroup_from_id - look up a memcg from a memcg id
4943 * @id: the memcg id to look up
4945 * Caller must hold rcu_read_lock().
4947 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
4949 WARN_ON_ONCE(!rcu_read_lock_held());
4950 return idr_find(&mem_cgroup_idr
, id
);
4953 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4955 struct mem_cgroup_per_node
*pn
;
4958 * This routine is called against possible nodes.
4959 * But it's BUG to call kmalloc() against offline node.
4961 * TODO: this routine can waste much memory for nodes which will
4962 * never be onlined. It's better to use memory hotplug callback
4965 if (!node_state(node
, N_NORMAL_MEMORY
))
4967 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4971 pn
->lruvec_stat_local
= alloc_percpu(struct lruvec_stat
);
4972 if (!pn
->lruvec_stat_local
) {
4977 pn
->lruvec_stat_cpu
= alloc_percpu(struct lruvec_stat
);
4978 if (!pn
->lruvec_stat_cpu
) {
4979 free_percpu(pn
->lruvec_stat_local
);
4984 lruvec_init(&pn
->lruvec
);
4985 pn
->usage_in_excess
= 0;
4986 pn
->on_tree
= false;
4989 memcg
->nodeinfo
[node
] = pn
;
4993 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4995 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
5000 free_percpu(pn
->lruvec_stat_cpu
);
5001 free_percpu(pn
->lruvec_stat_local
);
5005 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
5010 * Flush percpu vmstats and vmevents to guarantee the value correctness
5011 * on parent's and all ancestor levels.
5013 memcg_flush_percpu_vmstats(memcg
, false);
5014 memcg_flush_percpu_vmevents(memcg
);
5016 free_mem_cgroup_per_node_info(memcg
, node
);
5017 free_percpu(memcg
->vmstats_percpu
);
5018 free_percpu(memcg
->vmstats_local
);
5022 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
5024 memcg_wb_domain_exit(memcg
);
5025 __mem_cgroup_free(memcg
);
5028 static struct mem_cgroup
*mem_cgroup_alloc(void)
5030 struct mem_cgroup
*memcg
;
5033 int __maybe_unused i
;
5035 size
= sizeof(struct mem_cgroup
);
5036 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
5038 memcg
= kzalloc(size
, GFP_KERNEL
);
5042 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
5043 1, MEM_CGROUP_ID_MAX
,
5045 if (memcg
->id
.id
< 0)
5048 memcg
->vmstats_local
= alloc_percpu(struct memcg_vmstats_percpu
);
5049 if (!memcg
->vmstats_local
)
5052 memcg
->vmstats_percpu
= alloc_percpu(struct memcg_vmstats_percpu
);
5053 if (!memcg
->vmstats_percpu
)
5057 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
5060 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
5063 INIT_WORK(&memcg
->high_work
, high_work_func
);
5064 memcg
->last_scanned_node
= MAX_NUMNODES
;
5065 INIT_LIST_HEAD(&memcg
->oom_notify
);
5066 mutex_init(&memcg
->thresholds_lock
);
5067 spin_lock_init(&memcg
->move_lock
);
5068 vmpressure_init(&memcg
->vmpressure
);
5069 INIT_LIST_HEAD(&memcg
->event_list
);
5070 spin_lock_init(&memcg
->event_list_lock
);
5071 memcg
->socket_pressure
= jiffies
;
5072 #ifdef CONFIG_MEMCG_KMEM
5073 memcg
->kmemcg_id
= -1;
5075 #ifdef CONFIG_CGROUP_WRITEBACK
5076 INIT_LIST_HEAD(&memcg
->cgwb_list
);
5077 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5078 memcg
->cgwb_frn
[i
].done
=
5079 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq
);
5081 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
5084 mem_cgroup_id_remove(memcg
);
5085 __mem_cgroup_free(memcg
);
5089 static struct cgroup_subsys_state
* __ref
5090 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
5092 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
5093 struct mem_cgroup
*memcg
;
5094 long error
= -ENOMEM
;
5096 memcg
= mem_cgroup_alloc();
5098 return ERR_PTR(error
);
5100 memcg
->high
= PAGE_COUNTER_MAX
;
5101 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5103 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
5104 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
5106 if (parent
&& parent
->use_hierarchy
) {
5107 memcg
->use_hierarchy
= true;
5108 page_counter_init(&memcg
->memory
, &parent
->memory
);
5109 page_counter_init(&memcg
->swap
, &parent
->swap
);
5110 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
5111 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
5112 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
5114 page_counter_init(&memcg
->memory
, NULL
);
5115 page_counter_init(&memcg
->swap
, NULL
);
5116 page_counter_init(&memcg
->memsw
, NULL
);
5117 page_counter_init(&memcg
->kmem
, NULL
);
5118 page_counter_init(&memcg
->tcpmem
, NULL
);
5120 * Deeper hierachy with use_hierarchy == false doesn't make
5121 * much sense so let cgroup subsystem know about this
5122 * unfortunate state in our controller.
5124 if (parent
!= root_mem_cgroup
)
5125 memory_cgrp_subsys
.broken_hierarchy
= true;
5128 /* The following stuff does not apply to the root */
5130 #ifdef CONFIG_MEMCG_KMEM
5131 INIT_LIST_HEAD(&memcg
->kmem_caches
);
5133 root_mem_cgroup
= memcg
;
5137 error
= memcg_online_kmem(memcg
);
5141 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5142 static_branch_inc(&memcg_sockets_enabled_key
);
5146 mem_cgroup_id_remove(memcg
);
5147 mem_cgroup_free(memcg
);
5148 return ERR_PTR(-ENOMEM
);
5151 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
5153 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5156 * A memcg must be visible for memcg_expand_shrinker_maps()
5157 * by the time the maps are allocated. So, we allocate maps
5158 * here, when for_each_mem_cgroup() can't skip it.
5160 if (memcg_alloc_shrinker_maps(memcg
)) {
5161 mem_cgroup_id_remove(memcg
);
5165 /* Online state pins memcg ID, memcg ID pins CSS */
5166 refcount_set(&memcg
->id
.ref
, 1);
5171 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
5173 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5174 struct mem_cgroup_event
*event
, *tmp
;
5177 * Unregister events and notify userspace.
5178 * Notify userspace about cgroup removing only after rmdir of cgroup
5179 * directory to avoid race between userspace and kernelspace.
5181 spin_lock(&memcg
->event_list_lock
);
5182 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
5183 list_del_init(&event
->list
);
5184 schedule_work(&event
->remove
);
5186 spin_unlock(&memcg
->event_list_lock
);
5188 page_counter_set_min(&memcg
->memory
, 0);
5189 page_counter_set_low(&memcg
->memory
, 0);
5191 memcg_offline_kmem(memcg
);
5192 wb_memcg_offline(memcg
);
5194 drain_all_stock(memcg
);
5196 mem_cgroup_id_put(memcg
);
5199 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
5201 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5203 invalidate_reclaim_iterators(memcg
);
5206 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
5208 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5209 int __maybe_unused i
;
5211 #ifdef CONFIG_CGROUP_WRITEBACK
5212 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5213 wb_wait_for_completion(&memcg
->cgwb_frn
[i
].done
);
5215 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5216 static_branch_dec(&memcg_sockets_enabled_key
);
5218 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
5219 static_branch_dec(&memcg_sockets_enabled_key
);
5221 vmpressure_cleanup(&memcg
->vmpressure
);
5222 cancel_work_sync(&memcg
->high_work
);
5223 mem_cgroup_remove_from_trees(memcg
);
5224 memcg_free_shrinker_maps(memcg
);
5225 memcg_free_kmem(memcg
);
5226 mem_cgroup_free(memcg
);
5230 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5231 * @css: the target css
5233 * Reset the states of the mem_cgroup associated with @css. This is
5234 * invoked when the userland requests disabling on the default hierarchy
5235 * but the memcg is pinned through dependency. The memcg should stop
5236 * applying policies and should revert to the vanilla state as it may be
5237 * made visible again.
5239 * The current implementation only resets the essential configurations.
5240 * This needs to be expanded to cover all the visible parts.
5242 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
5244 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5246 page_counter_set_max(&memcg
->memory
, PAGE_COUNTER_MAX
);
5247 page_counter_set_max(&memcg
->swap
, PAGE_COUNTER_MAX
);
5248 page_counter_set_max(&memcg
->memsw
, PAGE_COUNTER_MAX
);
5249 page_counter_set_max(&memcg
->kmem
, PAGE_COUNTER_MAX
);
5250 page_counter_set_max(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
5251 page_counter_set_min(&memcg
->memory
, 0);
5252 page_counter_set_low(&memcg
->memory
, 0);
5253 memcg
->high
= PAGE_COUNTER_MAX
;
5254 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5255 memcg_wb_domain_size_changed(memcg
);
5259 /* Handlers for move charge at task migration. */
5260 static int mem_cgroup_do_precharge(unsigned long count
)
5264 /* Try a single bulk charge without reclaim first, kswapd may wake */
5265 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
5267 mc
.precharge
+= count
;
5271 /* Try charges one by one with reclaim, but do not retry */
5273 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
5287 enum mc_target_type
{
5294 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
5295 unsigned long addr
, pte_t ptent
)
5297 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
5299 if (!page
|| !page_mapped(page
))
5301 if (PageAnon(page
)) {
5302 if (!(mc
.flags
& MOVE_ANON
))
5305 if (!(mc
.flags
& MOVE_FILE
))
5308 if (!get_page_unless_zero(page
))
5314 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5315 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5316 pte_t ptent
, swp_entry_t
*entry
)
5318 struct page
*page
= NULL
;
5319 swp_entry_t ent
= pte_to_swp_entry(ptent
);
5321 if (!(mc
.flags
& MOVE_ANON
) || non_swap_entry(ent
))
5325 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5326 * a device and because they are not accessible by CPU they are store
5327 * as special swap entry in the CPU page table.
5329 if (is_device_private_entry(ent
)) {
5330 page
= device_private_entry_to_page(ent
);
5332 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5333 * a refcount of 1 when free (unlike normal page)
5335 if (!page_ref_add_unless(page
, 1, 1))
5341 * Because lookup_swap_cache() updates some statistics counter,
5342 * we call find_get_page() with swapper_space directly.
5344 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
5345 if (do_memsw_account())
5346 entry
->val
= ent
.val
;
5351 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5352 pte_t ptent
, swp_entry_t
*entry
)
5358 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5359 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5361 struct page
*page
= NULL
;
5362 struct address_space
*mapping
;
5365 if (!vma
->vm_file
) /* anonymous vma */
5367 if (!(mc
.flags
& MOVE_FILE
))
5370 mapping
= vma
->vm_file
->f_mapping
;
5371 pgoff
= linear_page_index(vma
, addr
);
5373 /* page is moved even if it's not RSS of this task(page-faulted). */
5375 /* shmem/tmpfs may report page out on swap: account for that too. */
5376 if (shmem_mapping(mapping
)) {
5377 page
= find_get_entry(mapping
, pgoff
);
5378 if (xa_is_value(page
)) {
5379 swp_entry_t swp
= radix_to_swp_entry(page
);
5380 if (do_memsw_account())
5382 page
= find_get_page(swap_address_space(swp
),
5386 page
= find_get_page(mapping
, pgoff
);
5388 page
= find_get_page(mapping
, pgoff
);
5394 * mem_cgroup_move_account - move account of the page
5396 * @compound: charge the page as compound or small page
5397 * @from: mem_cgroup which the page is moved from.
5398 * @to: mem_cgroup which the page is moved to. @from != @to.
5400 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5402 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5405 static int mem_cgroup_move_account(struct page
*page
,
5407 struct mem_cgroup
*from
,
5408 struct mem_cgroup
*to
)
5410 unsigned long flags
;
5411 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5415 VM_BUG_ON(from
== to
);
5416 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5417 VM_BUG_ON(compound
&& !PageTransHuge(page
));
5420 * Prevent mem_cgroup_migrate() from looking at
5421 * page->mem_cgroup of its source page while we change it.
5424 if (!trylock_page(page
))
5428 if (page
->mem_cgroup
!= from
)
5431 anon
= PageAnon(page
);
5433 spin_lock_irqsave(&from
->move_lock
, flags
);
5435 if (!anon
&& page_mapped(page
)) {
5436 __mod_memcg_state(from
, NR_FILE_MAPPED
, -nr_pages
);
5437 __mod_memcg_state(to
, NR_FILE_MAPPED
, nr_pages
);
5441 * move_lock grabbed above and caller set from->moving_account, so
5442 * mod_memcg_page_state will serialize updates to PageDirty.
5443 * So mapping should be stable for dirty pages.
5445 if (!anon
&& PageDirty(page
)) {
5446 struct address_space
*mapping
= page_mapping(page
);
5448 if (mapping_cap_account_dirty(mapping
)) {
5449 __mod_memcg_state(from
, NR_FILE_DIRTY
, -nr_pages
);
5450 __mod_memcg_state(to
, NR_FILE_DIRTY
, nr_pages
);
5454 if (PageWriteback(page
)) {
5455 __mod_memcg_state(from
, NR_WRITEBACK
, -nr_pages
);
5456 __mod_memcg_state(to
, NR_WRITEBACK
, nr_pages
);
5460 * It is safe to change page->mem_cgroup here because the page
5461 * is referenced, charged, and isolated - we can't race with
5462 * uncharging, charging, migration, or LRU putback.
5465 /* caller should have done css_get */
5466 page
->mem_cgroup
= to
;
5467 spin_unlock_irqrestore(&from
->move_lock
, flags
);
5471 local_irq_disable();
5472 mem_cgroup_charge_statistics(to
, page
, compound
, nr_pages
);
5473 memcg_check_events(to
, page
);
5474 mem_cgroup_charge_statistics(from
, page
, compound
, -nr_pages
);
5475 memcg_check_events(from
, page
);
5484 * get_mctgt_type - get target type of moving charge
5485 * @vma: the vma the pte to be checked belongs
5486 * @addr: the address corresponding to the pte to be checked
5487 * @ptent: the pte to be checked
5488 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5491 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5492 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5493 * move charge. if @target is not NULL, the page is stored in target->page
5494 * with extra refcnt got(Callers should handle it).
5495 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5496 * target for charge migration. if @target is not NULL, the entry is stored
5498 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5499 * (so ZONE_DEVICE page and thus not on the lru).
5500 * For now we such page is charge like a regular page would be as for all
5501 * intent and purposes it is just special memory taking the place of a
5504 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5506 * Called with pte lock held.
5509 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5510 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5512 struct page
*page
= NULL
;
5513 enum mc_target_type ret
= MC_TARGET_NONE
;
5514 swp_entry_t ent
= { .val
= 0 };
5516 if (pte_present(ptent
))
5517 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5518 else if (is_swap_pte(ptent
))
5519 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
5520 else if (pte_none(ptent
))
5521 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5523 if (!page
&& !ent
.val
)
5527 * Do only loose check w/o serialization.
5528 * mem_cgroup_move_account() checks the page is valid or
5529 * not under LRU exclusion.
5531 if (page
->mem_cgroup
== mc
.from
) {
5532 ret
= MC_TARGET_PAGE
;
5533 if (is_device_private_page(page
))
5534 ret
= MC_TARGET_DEVICE
;
5536 target
->page
= page
;
5538 if (!ret
|| !target
)
5542 * There is a swap entry and a page doesn't exist or isn't charged.
5543 * But we cannot move a tail-page in a THP.
5545 if (ent
.val
&& !ret
&& (!page
|| !PageTransCompound(page
)) &&
5546 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
5547 ret
= MC_TARGET_SWAP
;
5554 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5556 * We don't consider PMD mapped swapping or file mapped pages because THP does
5557 * not support them for now.
5558 * Caller should make sure that pmd_trans_huge(pmd) is true.
5560 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5561 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5563 struct page
*page
= NULL
;
5564 enum mc_target_type ret
= MC_TARGET_NONE
;
5566 if (unlikely(is_swap_pmd(pmd
))) {
5567 VM_BUG_ON(thp_migration_supported() &&
5568 !is_pmd_migration_entry(pmd
));
5571 page
= pmd_page(pmd
);
5572 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
5573 if (!(mc
.flags
& MOVE_ANON
))
5575 if (page
->mem_cgroup
== mc
.from
) {
5576 ret
= MC_TARGET_PAGE
;
5579 target
->page
= page
;
5585 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5586 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5588 return MC_TARGET_NONE
;
5592 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5593 unsigned long addr
, unsigned long end
,
5594 struct mm_walk
*walk
)
5596 struct vm_area_struct
*vma
= walk
->vma
;
5600 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5603 * Note their can not be MC_TARGET_DEVICE for now as we do not
5604 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5605 * this might change.
5607 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5608 mc
.precharge
+= HPAGE_PMD_NR
;
5613 if (pmd_trans_unstable(pmd
))
5615 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5616 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5617 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5618 mc
.precharge
++; /* increment precharge temporarily */
5619 pte_unmap_unlock(pte
- 1, ptl
);
5625 static const struct mm_walk_ops precharge_walk_ops
= {
5626 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5629 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5631 unsigned long precharge
;
5633 down_read(&mm
->mmap_sem
);
5634 walk_page_range(mm
, 0, mm
->highest_vm_end
, &precharge_walk_ops
, NULL
);
5635 up_read(&mm
->mmap_sem
);
5637 precharge
= mc
.precharge
;
5643 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5645 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5647 VM_BUG_ON(mc
.moving_task
);
5648 mc
.moving_task
= current
;
5649 return mem_cgroup_do_precharge(precharge
);
5652 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5653 static void __mem_cgroup_clear_mc(void)
5655 struct mem_cgroup
*from
= mc
.from
;
5656 struct mem_cgroup
*to
= mc
.to
;
5658 /* we must uncharge all the leftover precharges from mc.to */
5660 cancel_charge(mc
.to
, mc
.precharge
);
5664 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5665 * we must uncharge here.
5667 if (mc
.moved_charge
) {
5668 cancel_charge(mc
.from
, mc
.moved_charge
);
5669 mc
.moved_charge
= 0;
5671 /* we must fixup refcnts and charges */
5672 if (mc
.moved_swap
) {
5673 /* uncharge swap account from the old cgroup */
5674 if (!mem_cgroup_is_root(mc
.from
))
5675 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
5677 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
5680 * we charged both to->memory and to->memsw, so we
5681 * should uncharge to->memory.
5683 if (!mem_cgroup_is_root(mc
.to
))
5684 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
5686 mem_cgroup_id_get_many(mc
.to
, mc
.moved_swap
);
5687 css_put_many(&mc
.to
->css
, mc
.moved_swap
);
5691 memcg_oom_recover(from
);
5692 memcg_oom_recover(to
);
5693 wake_up_all(&mc
.waitq
);
5696 static void mem_cgroup_clear_mc(void)
5698 struct mm_struct
*mm
= mc
.mm
;
5701 * we must clear moving_task before waking up waiters at the end of
5704 mc
.moving_task
= NULL
;
5705 __mem_cgroup_clear_mc();
5706 spin_lock(&mc
.lock
);
5710 spin_unlock(&mc
.lock
);
5715 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5717 struct cgroup_subsys_state
*css
;
5718 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
5719 struct mem_cgroup
*from
;
5720 struct task_struct
*leader
, *p
;
5721 struct mm_struct
*mm
;
5722 unsigned long move_flags
;
5725 /* charge immigration isn't supported on the default hierarchy */
5726 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5730 * Multi-process migrations only happen on the default hierarchy
5731 * where charge immigration is not used. Perform charge
5732 * immigration if @tset contains a leader and whine if there are
5736 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
5739 memcg
= mem_cgroup_from_css(css
);
5745 * We are now commited to this value whatever it is. Changes in this
5746 * tunable will only affect upcoming migrations, not the current one.
5747 * So we need to save it, and keep it going.
5749 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
5753 from
= mem_cgroup_from_task(p
);
5755 VM_BUG_ON(from
== memcg
);
5757 mm
= get_task_mm(p
);
5760 /* We move charges only when we move a owner of the mm */
5761 if (mm
->owner
== p
) {
5764 VM_BUG_ON(mc
.precharge
);
5765 VM_BUG_ON(mc
.moved_charge
);
5766 VM_BUG_ON(mc
.moved_swap
);
5768 spin_lock(&mc
.lock
);
5772 mc
.flags
= move_flags
;
5773 spin_unlock(&mc
.lock
);
5774 /* We set mc.moving_task later */
5776 ret
= mem_cgroup_precharge_mc(mm
);
5778 mem_cgroup_clear_mc();
5785 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5788 mem_cgroup_clear_mc();
5791 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
5792 unsigned long addr
, unsigned long end
,
5793 struct mm_walk
*walk
)
5796 struct vm_area_struct
*vma
= walk
->vma
;
5799 enum mc_target_type target_type
;
5800 union mc_target target
;
5803 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5805 if (mc
.precharge
< HPAGE_PMD_NR
) {
5809 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
5810 if (target_type
== MC_TARGET_PAGE
) {
5812 if (!isolate_lru_page(page
)) {
5813 if (!mem_cgroup_move_account(page
, true,
5815 mc
.precharge
-= HPAGE_PMD_NR
;
5816 mc
.moved_charge
+= HPAGE_PMD_NR
;
5818 putback_lru_page(page
);
5821 } else if (target_type
== MC_TARGET_DEVICE
) {
5823 if (!mem_cgroup_move_account(page
, true,
5825 mc
.precharge
-= HPAGE_PMD_NR
;
5826 mc
.moved_charge
+= HPAGE_PMD_NR
;
5834 if (pmd_trans_unstable(pmd
))
5837 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5838 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
5839 pte_t ptent
= *(pte
++);
5840 bool device
= false;
5846 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
5847 case MC_TARGET_DEVICE
:
5850 case MC_TARGET_PAGE
:
5853 * We can have a part of the split pmd here. Moving it
5854 * can be done but it would be too convoluted so simply
5855 * ignore such a partial THP and keep it in original
5856 * memcg. There should be somebody mapping the head.
5858 if (PageTransCompound(page
))
5860 if (!device
&& isolate_lru_page(page
))
5862 if (!mem_cgroup_move_account(page
, false,
5865 /* we uncharge from mc.from later. */
5869 putback_lru_page(page
);
5870 put
: /* get_mctgt_type() gets the page */
5873 case MC_TARGET_SWAP
:
5875 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
5877 /* we fixup refcnts and charges later. */
5885 pte_unmap_unlock(pte
- 1, ptl
);
5890 * We have consumed all precharges we got in can_attach().
5891 * We try charge one by one, but don't do any additional
5892 * charges to mc.to if we have failed in charge once in attach()
5895 ret
= mem_cgroup_do_precharge(1);
5903 static const struct mm_walk_ops charge_walk_ops
= {
5904 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
5907 static void mem_cgroup_move_charge(void)
5909 lru_add_drain_all();
5911 * Signal lock_page_memcg() to take the memcg's move_lock
5912 * while we're moving its pages to another memcg. Then wait
5913 * for already started RCU-only updates to finish.
5915 atomic_inc(&mc
.from
->moving_account
);
5918 if (unlikely(!down_read_trylock(&mc
.mm
->mmap_sem
))) {
5920 * Someone who are holding the mmap_sem might be waiting in
5921 * waitq. So we cancel all extra charges, wake up all waiters,
5922 * and retry. Because we cancel precharges, we might not be able
5923 * to move enough charges, but moving charge is a best-effort
5924 * feature anyway, so it wouldn't be a big problem.
5926 __mem_cgroup_clear_mc();
5931 * When we have consumed all precharges and failed in doing
5932 * additional charge, the page walk just aborts.
5934 walk_page_range(mc
.mm
, 0, mc
.mm
->highest_vm_end
, &charge_walk_ops
,
5937 up_read(&mc
.mm
->mmap_sem
);
5938 atomic_dec(&mc
.from
->moving_account
);
5941 static void mem_cgroup_move_task(void)
5944 mem_cgroup_move_charge();
5945 mem_cgroup_clear_mc();
5948 #else /* !CONFIG_MMU */
5949 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5953 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5956 static void mem_cgroup_move_task(void)
5962 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5963 * to verify whether we're attached to the default hierarchy on each mount
5966 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5969 * use_hierarchy is forced on the default hierarchy. cgroup core
5970 * guarantees that @root doesn't have any children, so turning it
5971 * on for the root memcg is enough.
5973 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5974 root_mem_cgroup
->use_hierarchy
= true;
5976 root_mem_cgroup
->use_hierarchy
= false;
5979 static int seq_puts_memcg_tunable(struct seq_file
*m
, unsigned long value
)
5981 if (value
== PAGE_COUNTER_MAX
)
5982 seq_puts(m
, "max\n");
5984 seq_printf(m
, "%llu\n", (u64
)value
* PAGE_SIZE
);
5989 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
5992 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5994 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
5997 static int memory_min_show(struct seq_file
*m
, void *v
)
5999 return seq_puts_memcg_tunable(m
,
6000 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.min
));
6003 static ssize_t
memory_min_write(struct kernfs_open_file
*of
,
6004 char *buf
, size_t nbytes
, loff_t off
)
6006 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6010 buf
= strstrip(buf
);
6011 err
= page_counter_memparse(buf
, "max", &min
);
6015 page_counter_set_min(&memcg
->memory
, min
);
6020 static int memory_low_show(struct seq_file
*m
, void *v
)
6022 return seq_puts_memcg_tunable(m
,
6023 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.low
));
6026 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
6027 char *buf
, size_t nbytes
, loff_t off
)
6029 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6033 buf
= strstrip(buf
);
6034 err
= page_counter_memparse(buf
, "max", &low
);
6038 page_counter_set_low(&memcg
->memory
, low
);
6043 static int memory_high_show(struct seq_file
*m
, void *v
)
6045 return seq_puts_memcg_tunable(m
, READ_ONCE(mem_cgroup_from_seq(m
)->high
));
6048 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
6049 char *buf
, size_t nbytes
, loff_t off
)
6051 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6052 unsigned long nr_pages
;
6056 buf
= strstrip(buf
);
6057 err
= page_counter_memparse(buf
, "max", &high
);
6063 nr_pages
= page_counter_read(&memcg
->memory
);
6064 if (nr_pages
> high
)
6065 try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
6068 memcg_wb_domain_size_changed(memcg
);
6072 static int memory_max_show(struct seq_file
*m
, void *v
)
6074 return seq_puts_memcg_tunable(m
,
6075 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.max
));
6078 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
6079 char *buf
, size_t nbytes
, loff_t off
)
6081 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6082 unsigned int nr_reclaims
= MEM_CGROUP_RECLAIM_RETRIES
;
6083 bool drained
= false;
6087 buf
= strstrip(buf
);
6088 err
= page_counter_memparse(buf
, "max", &max
);
6092 xchg(&memcg
->memory
.max
, max
);
6095 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6097 if (nr_pages
<= max
)
6100 if (signal_pending(current
)) {
6106 drain_all_stock(memcg
);
6112 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
6118 memcg_memory_event(memcg
, MEMCG_OOM
);
6119 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
6123 memcg_wb_domain_size_changed(memcg
);
6127 static void __memory_events_show(struct seq_file
*m
, atomic_long_t
*events
)
6129 seq_printf(m
, "low %lu\n", atomic_long_read(&events
[MEMCG_LOW
]));
6130 seq_printf(m
, "high %lu\n", atomic_long_read(&events
[MEMCG_HIGH
]));
6131 seq_printf(m
, "max %lu\n", atomic_long_read(&events
[MEMCG_MAX
]));
6132 seq_printf(m
, "oom %lu\n", atomic_long_read(&events
[MEMCG_OOM
]));
6133 seq_printf(m
, "oom_kill %lu\n",
6134 atomic_long_read(&events
[MEMCG_OOM_KILL
]));
6137 static int memory_events_show(struct seq_file
*m
, void *v
)
6139 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6141 __memory_events_show(m
, memcg
->memory_events
);
6145 static int memory_events_local_show(struct seq_file
*m
, void *v
)
6147 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6149 __memory_events_show(m
, memcg
->memory_events_local
);
6153 static int memory_stat_show(struct seq_file
*m
, void *v
)
6155 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6158 buf
= memory_stat_format(memcg
);
6166 static int memory_oom_group_show(struct seq_file
*m
, void *v
)
6168 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6170 seq_printf(m
, "%d\n", memcg
->oom_group
);
6175 static ssize_t
memory_oom_group_write(struct kernfs_open_file
*of
,
6176 char *buf
, size_t nbytes
, loff_t off
)
6178 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6181 buf
= strstrip(buf
);
6185 ret
= kstrtoint(buf
, 0, &oom_group
);
6189 if (oom_group
!= 0 && oom_group
!= 1)
6192 memcg
->oom_group
= oom_group
;
6197 static struct cftype memory_files
[] = {
6200 .flags
= CFTYPE_NOT_ON_ROOT
,
6201 .read_u64
= memory_current_read
,
6205 .flags
= CFTYPE_NOT_ON_ROOT
,
6206 .seq_show
= memory_min_show
,
6207 .write
= memory_min_write
,
6211 .flags
= CFTYPE_NOT_ON_ROOT
,
6212 .seq_show
= memory_low_show
,
6213 .write
= memory_low_write
,
6217 .flags
= CFTYPE_NOT_ON_ROOT
,
6218 .seq_show
= memory_high_show
,
6219 .write
= memory_high_write
,
6223 .flags
= CFTYPE_NOT_ON_ROOT
,
6224 .seq_show
= memory_max_show
,
6225 .write
= memory_max_write
,
6229 .flags
= CFTYPE_NOT_ON_ROOT
,
6230 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
6231 .seq_show
= memory_events_show
,
6234 .name
= "events.local",
6235 .flags
= CFTYPE_NOT_ON_ROOT
,
6236 .file_offset
= offsetof(struct mem_cgroup
, events_local_file
),
6237 .seq_show
= memory_events_local_show
,
6241 .flags
= CFTYPE_NOT_ON_ROOT
,
6242 .seq_show
= memory_stat_show
,
6245 .name
= "oom.group",
6246 .flags
= CFTYPE_NOT_ON_ROOT
| CFTYPE_NS_DELEGATABLE
,
6247 .seq_show
= memory_oom_group_show
,
6248 .write
= memory_oom_group_write
,
6253 struct cgroup_subsys memory_cgrp_subsys
= {
6254 .css_alloc
= mem_cgroup_css_alloc
,
6255 .css_online
= mem_cgroup_css_online
,
6256 .css_offline
= mem_cgroup_css_offline
,
6257 .css_released
= mem_cgroup_css_released
,
6258 .css_free
= mem_cgroup_css_free
,
6259 .css_reset
= mem_cgroup_css_reset
,
6260 .can_attach
= mem_cgroup_can_attach
,
6261 .cancel_attach
= mem_cgroup_cancel_attach
,
6262 .post_attach
= mem_cgroup_move_task
,
6263 .bind
= mem_cgroup_bind
,
6264 .dfl_cftypes
= memory_files
,
6265 .legacy_cftypes
= mem_cgroup_legacy_files
,
6270 * mem_cgroup_protected - check if memory consumption is in the normal range
6271 * @root: the top ancestor of the sub-tree being checked
6272 * @memcg: the memory cgroup to check
6274 * WARNING: This function is not stateless! It can only be used as part
6275 * of a top-down tree iteration, not for isolated queries.
6277 * Returns one of the following:
6278 * MEMCG_PROT_NONE: cgroup memory is not protected
6279 * MEMCG_PROT_LOW: cgroup memory is protected as long there is
6280 * an unprotected supply of reclaimable memory from other cgroups.
6281 * MEMCG_PROT_MIN: cgroup memory is protected
6283 * @root is exclusive; it is never protected when looked at directly
6285 * To provide a proper hierarchical behavior, effective memory.min/low values
6286 * are used. Below is the description of how effective memory.low is calculated.
6287 * Effective memory.min values is calculated in the same way.
6289 * Effective memory.low is always equal or less than the original memory.low.
6290 * If there is no memory.low overcommittment (which is always true for
6291 * top-level memory cgroups), these two values are equal.
6292 * Otherwise, it's a part of parent's effective memory.low,
6293 * calculated as a cgroup's memory.low usage divided by sum of sibling's
6294 * memory.low usages, where memory.low usage is the size of actually
6298 * elow = min( memory.low, parent->elow * ------------------ ),
6299 * siblings_low_usage
6301 * | memory.current, if memory.current < memory.low
6306 * Such definition of the effective memory.low provides the expected
6307 * hierarchical behavior: parent's memory.low value is limiting
6308 * children, unprotected memory is reclaimed first and cgroups,
6309 * which are not using their guarantee do not affect actual memory
6312 * For example, if there are memcgs A, A/B, A/C, A/D and A/E:
6314 * A A/memory.low = 2G, A/memory.current = 6G
6316 * BC DE B/memory.low = 3G B/memory.current = 2G
6317 * C/memory.low = 1G C/memory.current = 2G
6318 * D/memory.low = 0 D/memory.current = 2G
6319 * E/memory.low = 10G E/memory.current = 0
6321 * and the memory pressure is applied, the following memory distribution
6322 * is expected (approximately):
6324 * A/memory.current = 2G
6326 * B/memory.current = 1.3G
6327 * C/memory.current = 0.6G
6328 * D/memory.current = 0
6329 * E/memory.current = 0
6331 * These calculations require constant tracking of the actual low usages
6332 * (see propagate_protected_usage()), as well as recursive calculation of
6333 * effective memory.low values. But as we do call mem_cgroup_protected()
6334 * path for each memory cgroup top-down from the reclaim,
6335 * it's possible to optimize this part, and save calculated elow
6336 * for next usage. This part is intentionally racy, but it's ok,
6337 * as memory.low is a best-effort mechanism.
6339 enum mem_cgroup_protection
mem_cgroup_protected(struct mem_cgroup
*root
,
6340 struct mem_cgroup
*memcg
)
6342 struct mem_cgroup
*parent
;
6343 unsigned long emin
, parent_emin
;
6344 unsigned long elow
, parent_elow
;
6345 unsigned long usage
;
6347 if (mem_cgroup_disabled())
6348 return MEMCG_PROT_NONE
;
6351 root
= root_mem_cgroup
;
6353 return MEMCG_PROT_NONE
;
6355 usage
= page_counter_read(&memcg
->memory
);
6357 return MEMCG_PROT_NONE
;
6359 emin
= memcg
->memory
.min
;
6360 elow
= memcg
->memory
.low
;
6362 parent
= parent_mem_cgroup(memcg
);
6363 /* No parent means a non-hierarchical mode on v1 memcg */
6365 return MEMCG_PROT_NONE
;
6370 parent_emin
= READ_ONCE(parent
->memory
.emin
);
6371 emin
= min(emin
, parent_emin
);
6372 if (emin
&& parent_emin
) {
6373 unsigned long min_usage
, siblings_min_usage
;
6375 min_usage
= min(usage
, memcg
->memory
.min
);
6376 siblings_min_usage
= atomic_long_read(
6377 &parent
->memory
.children_min_usage
);
6379 if (min_usage
&& siblings_min_usage
)
6380 emin
= min(emin
, parent_emin
* min_usage
/
6381 siblings_min_usage
);
6384 parent_elow
= READ_ONCE(parent
->memory
.elow
);
6385 elow
= min(elow
, parent_elow
);
6386 if (elow
&& parent_elow
) {
6387 unsigned long low_usage
, siblings_low_usage
;
6389 low_usage
= min(usage
, memcg
->memory
.low
);
6390 siblings_low_usage
= atomic_long_read(
6391 &parent
->memory
.children_low_usage
);
6393 if (low_usage
&& siblings_low_usage
)
6394 elow
= min(elow
, parent_elow
* low_usage
/
6395 siblings_low_usage
);
6399 memcg
->memory
.emin
= emin
;
6400 memcg
->memory
.elow
= elow
;
6403 return MEMCG_PROT_MIN
;
6404 else if (usage
<= elow
)
6405 return MEMCG_PROT_LOW
;
6407 return MEMCG_PROT_NONE
;
6411 * mem_cgroup_try_charge - try charging a page
6412 * @page: page to charge
6413 * @mm: mm context of the victim
6414 * @gfp_mask: reclaim mode
6415 * @memcgp: charged memcg return
6416 * @compound: charge the page as compound or small page
6418 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6419 * pages according to @gfp_mask if necessary.
6421 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
6422 * Otherwise, an error code is returned.
6424 * After page->mapping has been set up, the caller must finalize the
6425 * charge with mem_cgroup_commit_charge(). Or abort the transaction
6426 * with mem_cgroup_cancel_charge() in case page instantiation fails.
6428 int mem_cgroup_try_charge(struct page
*page
, struct mm_struct
*mm
,
6429 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
,
6432 struct mem_cgroup
*memcg
= NULL
;
6433 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
6436 if (mem_cgroup_disabled())
6439 if (PageSwapCache(page
)) {
6441 * Every swap fault against a single page tries to charge the
6442 * page, bail as early as possible. shmem_unuse() encounters
6443 * already charged pages, too. The USED bit is protected by
6444 * the page lock, which serializes swap cache removal, which
6445 * in turn serializes uncharging.
6447 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
6448 if (compound_head(page
)->mem_cgroup
)
6451 if (do_swap_account
) {
6452 swp_entry_t ent
= { .val
= page_private(page
), };
6453 unsigned short id
= lookup_swap_cgroup_id(ent
);
6456 memcg
= mem_cgroup_from_id(id
);
6457 if (memcg
&& !css_tryget_online(&memcg
->css
))
6464 memcg
= get_mem_cgroup_from_mm(mm
);
6466 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
6468 css_put(&memcg
->css
);
6474 int mem_cgroup_try_charge_delay(struct page
*page
, struct mm_struct
*mm
,
6475 gfp_t gfp_mask
, struct mem_cgroup
**memcgp
,
6478 struct mem_cgroup
*memcg
;
6481 ret
= mem_cgroup_try_charge(page
, mm
, gfp_mask
, memcgp
, compound
);
6483 mem_cgroup_throttle_swaprate(memcg
, page_to_nid(page
), gfp_mask
);
6488 * mem_cgroup_commit_charge - commit a page charge
6489 * @page: page to charge
6490 * @memcg: memcg to charge the page to
6491 * @lrucare: page might be on LRU already
6492 * @compound: charge the page as compound or small page
6494 * Finalize a charge transaction started by mem_cgroup_try_charge(),
6495 * after page->mapping has been set up. This must happen atomically
6496 * as part of the page instantiation, i.e. under the page table lock
6497 * for anonymous pages, under the page lock for page and swap cache.
6499 * In addition, the page must not be on the LRU during the commit, to
6500 * prevent racing with task migration. If it might be, use @lrucare.
6502 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
6504 void mem_cgroup_commit_charge(struct page
*page
, struct mem_cgroup
*memcg
,
6505 bool lrucare
, bool compound
)
6507 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
6509 VM_BUG_ON_PAGE(!page
->mapping
, page
);
6510 VM_BUG_ON_PAGE(PageLRU(page
) && !lrucare
, page
);
6512 if (mem_cgroup_disabled())
6515 * Swap faults will attempt to charge the same page multiple
6516 * times. But reuse_swap_page() might have removed the page
6517 * from swapcache already, so we can't check PageSwapCache().
6522 commit_charge(page
, memcg
, lrucare
);
6524 local_irq_disable();
6525 mem_cgroup_charge_statistics(memcg
, page
, compound
, nr_pages
);
6526 memcg_check_events(memcg
, page
);
6529 if (do_memsw_account() && PageSwapCache(page
)) {
6530 swp_entry_t entry
= { .val
= page_private(page
) };
6532 * The swap entry might not get freed for a long time,
6533 * let's not wait for it. The page already received a
6534 * memory+swap charge, drop the swap entry duplicate.
6536 mem_cgroup_uncharge_swap(entry
, nr_pages
);
6541 * mem_cgroup_cancel_charge - cancel a page charge
6542 * @page: page to charge
6543 * @memcg: memcg to charge the page to
6544 * @compound: charge the page as compound or small page
6546 * Cancel a charge transaction started by mem_cgroup_try_charge().
6548 void mem_cgroup_cancel_charge(struct page
*page
, struct mem_cgroup
*memcg
,
6551 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
6553 if (mem_cgroup_disabled())
6556 * Swap faults will attempt to charge the same page multiple
6557 * times. But reuse_swap_page() might have removed the page
6558 * from swapcache already, so we can't check PageSwapCache().
6563 cancel_charge(memcg
, nr_pages
);
6566 struct uncharge_gather
{
6567 struct mem_cgroup
*memcg
;
6568 unsigned long pgpgout
;
6569 unsigned long nr_anon
;
6570 unsigned long nr_file
;
6571 unsigned long nr_kmem
;
6572 unsigned long nr_huge
;
6573 unsigned long nr_shmem
;
6574 struct page
*dummy_page
;
6577 static inline void uncharge_gather_clear(struct uncharge_gather
*ug
)
6579 memset(ug
, 0, sizeof(*ug
));
6582 static void uncharge_batch(const struct uncharge_gather
*ug
)
6584 unsigned long nr_pages
= ug
->nr_anon
+ ug
->nr_file
+ ug
->nr_kmem
;
6585 unsigned long flags
;
6587 if (!mem_cgroup_is_root(ug
->memcg
)) {
6588 page_counter_uncharge(&ug
->memcg
->memory
, nr_pages
);
6589 if (do_memsw_account())
6590 page_counter_uncharge(&ug
->memcg
->memsw
, nr_pages
);
6591 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && ug
->nr_kmem
)
6592 page_counter_uncharge(&ug
->memcg
->kmem
, ug
->nr_kmem
);
6593 memcg_oom_recover(ug
->memcg
);
6596 local_irq_save(flags
);
6597 __mod_memcg_state(ug
->memcg
, MEMCG_RSS
, -ug
->nr_anon
);
6598 __mod_memcg_state(ug
->memcg
, MEMCG_CACHE
, -ug
->nr_file
);
6599 __mod_memcg_state(ug
->memcg
, MEMCG_RSS_HUGE
, -ug
->nr_huge
);
6600 __mod_memcg_state(ug
->memcg
, NR_SHMEM
, -ug
->nr_shmem
);
6601 __count_memcg_events(ug
->memcg
, PGPGOUT
, ug
->pgpgout
);
6602 __this_cpu_add(ug
->memcg
->vmstats_percpu
->nr_page_events
, nr_pages
);
6603 memcg_check_events(ug
->memcg
, ug
->dummy_page
);
6604 local_irq_restore(flags
);
6606 if (!mem_cgroup_is_root(ug
->memcg
))
6607 css_put_many(&ug
->memcg
->css
, nr_pages
);
6610 static void uncharge_page(struct page
*page
, struct uncharge_gather
*ug
)
6612 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6613 VM_BUG_ON_PAGE(page_count(page
) && !is_zone_device_page(page
) &&
6614 !PageHWPoison(page
) , page
);
6616 if (!page
->mem_cgroup
)
6620 * Nobody should be changing or seriously looking at
6621 * page->mem_cgroup at this point, we have fully
6622 * exclusive access to the page.
6625 if (ug
->memcg
!= page
->mem_cgroup
) {
6628 uncharge_gather_clear(ug
);
6630 ug
->memcg
= page
->mem_cgroup
;
6633 if (!PageKmemcg(page
)) {
6634 unsigned int nr_pages
= 1;
6636 if (PageTransHuge(page
)) {
6637 nr_pages
= compound_nr(page
);
6638 ug
->nr_huge
+= nr_pages
;
6641 ug
->nr_anon
+= nr_pages
;
6643 ug
->nr_file
+= nr_pages
;
6644 if (PageSwapBacked(page
))
6645 ug
->nr_shmem
+= nr_pages
;
6649 ug
->nr_kmem
+= compound_nr(page
);
6650 __ClearPageKmemcg(page
);
6653 ug
->dummy_page
= page
;
6654 page
->mem_cgroup
= NULL
;
6657 static void uncharge_list(struct list_head
*page_list
)
6659 struct uncharge_gather ug
;
6660 struct list_head
*next
;
6662 uncharge_gather_clear(&ug
);
6665 * Note that the list can be a single page->lru; hence the
6666 * do-while loop instead of a simple list_for_each_entry().
6668 next
= page_list
->next
;
6672 page
= list_entry(next
, struct page
, lru
);
6673 next
= page
->lru
.next
;
6675 uncharge_page(page
, &ug
);
6676 } while (next
!= page_list
);
6679 uncharge_batch(&ug
);
6683 * mem_cgroup_uncharge - uncharge a page
6684 * @page: page to uncharge
6686 * Uncharge a page previously charged with mem_cgroup_try_charge() and
6687 * mem_cgroup_commit_charge().
6689 void mem_cgroup_uncharge(struct page
*page
)
6691 struct uncharge_gather ug
;
6693 if (mem_cgroup_disabled())
6696 /* Don't touch page->lru of any random page, pre-check: */
6697 if (!page
->mem_cgroup
)
6700 uncharge_gather_clear(&ug
);
6701 uncharge_page(page
, &ug
);
6702 uncharge_batch(&ug
);
6706 * mem_cgroup_uncharge_list - uncharge a list of page
6707 * @page_list: list of pages to uncharge
6709 * Uncharge a list of pages previously charged with
6710 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
6712 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
6714 if (mem_cgroup_disabled())
6717 if (!list_empty(page_list
))
6718 uncharge_list(page_list
);
6722 * mem_cgroup_migrate - charge a page's replacement
6723 * @oldpage: currently circulating page
6724 * @newpage: replacement page
6726 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6727 * be uncharged upon free.
6729 * Both pages must be locked, @newpage->mapping must be set up.
6731 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
6733 struct mem_cgroup
*memcg
;
6734 unsigned int nr_pages
;
6736 unsigned long flags
;
6738 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
6739 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
6740 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
6741 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
6744 if (mem_cgroup_disabled())
6747 /* Page cache replacement: new page already charged? */
6748 if (newpage
->mem_cgroup
)
6751 /* Swapcache readahead pages can get replaced before being charged */
6752 memcg
= oldpage
->mem_cgroup
;
6756 /* Force-charge the new page. The old one will be freed soon */
6757 compound
= PageTransHuge(newpage
);
6758 nr_pages
= compound
? hpage_nr_pages(newpage
) : 1;
6760 page_counter_charge(&memcg
->memory
, nr_pages
);
6761 if (do_memsw_account())
6762 page_counter_charge(&memcg
->memsw
, nr_pages
);
6763 css_get_many(&memcg
->css
, nr_pages
);
6765 commit_charge(newpage
, memcg
, false);
6767 local_irq_save(flags
);
6768 mem_cgroup_charge_statistics(memcg
, newpage
, compound
, nr_pages
);
6769 memcg_check_events(memcg
, newpage
);
6770 local_irq_restore(flags
);
6773 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
6774 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
6776 void mem_cgroup_sk_alloc(struct sock
*sk
)
6778 struct mem_cgroup
*memcg
;
6780 if (!mem_cgroup_sockets_enabled
)
6784 * Socket cloning can throw us here with sk_memcg already
6785 * filled. It won't however, necessarily happen from
6786 * process context. So the test for root memcg given
6787 * the current task's memcg won't help us in this case.
6789 * Respecting the original socket's memcg is a better
6790 * decision in this case.
6793 css_get(&sk
->sk_memcg
->css
);
6798 memcg
= mem_cgroup_from_task(current
);
6799 if (memcg
== root_mem_cgroup
)
6801 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
6803 if (css_tryget_online(&memcg
->css
))
6804 sk
->sk_memcg
= memcg
;
6809 void mem_cgroup_sk_free(struct sock
*sk
)
6812 css_put(&sk
->sk_memcg
->css
);
6816 * mem_cgroup_charge_skmem - charge socket memory
6817 * @memcg: memcg to charge
6818 * @nr_pages: number of pages to charge
6820 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
6821 * @memcg's configured limit, %false if the charge had to be forced.
6823 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
6825 gfp_t gfp_mask
= GFP_KERNEL
;
6827 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
6828 struct page_counter
*fail
;
6830 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
6831 memcg
->tcpmem_pressure
= 0;
6834 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
6835 memcg
->tcpmem_pressure
= 1;
6839 /* Don't block in the packet receive path */
6841 gfp_mask
= GFP_NOWAIT
;
6843 mod_memcg_state(memcg
, MEMCG_SOCK
, nr_pages
);
6845 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
6848 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
6853 * mem_cgroup_uncharge_skmem - uncharge socket memory
6854 * @memcg: memcg to uncharge
6855 * @nr_pages: number of pages to uncharge
6857 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
6859 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
6860 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
6864 mod_memcg_state(memcg
, MEMCG_SOCK
, -nr_pages
);
6866 refill_stock(memcg
, nr_pages
);
6869 static int __init
cgroup_memory(char *s
)
6873 while ((token
= strsep(&s
, ",")) != NULL
) {
6876 if (!strcmp(token
, "nosocket"))
6877 cgroup_memory_nosocket
= true;
6878 if (!strcmp(token
, "nokmem"))
6879 cgroup_memory_nokmem
= true;
6883 __setup("cgroup.memory=", cgroup_memory
);
6886 * subsys_initcall() for memory controller.
6888 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
6889 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
6890 * basically everything that doesn't depend on a specific mem_cgroup structure
6891 * should be initialized from here.
6893 static int __init
mem_cgroup_init(void)
6897 #ifdef CONFIG_MEMCG_KMEM
6899 * Kmem cache creation is mostly done with the slab_mutex held,
6900 * so use a workqueue with limited concurrency to avoid stalling
6901 * all worker threads in case lots of cgroups are created and
6902 * destroyed simultaneously.
6904 memcg_kmem_cache_wq
= alloc_workqueue("memcg_kmem_cache", 0, 1);
6905 BUG_ON(!memcg_kmem_cache_wq
);
6908 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
6909 memcg_hotplug_cpu_dead
);
6911 for_each_possible_cpu(cpu
)
6912 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
6915 for_each_node(node
) {
6916 struct mem_cgroup_tree_per_node
*rtpn
;
6918 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
6919 node_online(node
) ? node
: NUMA_NO_NODE
);
6921 rtpn
->rb_root
= RB_ROOT
;
6922 rtpn
->rb_rightmost
= NULL
;
6923 spin_lock_init(&rtpn
->lock
);
6924 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6929 subsys_initcall(mem_cgroup_init
);
6931 #ifdef CONFIG_MEMCG_SWAP
6932 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
6934 while (!refcount_inc_not_zero(&memcg
->id
.ref
)) {
6936 * The root cgroup cannot be destroyed, so it's refcount must
6939 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
6943 memcg
= parent_mem_cgroup(memcg
);
6945 memcg
= root_mem_cgroup
;
6951 * mem_cgroup_swapout - transfer a memsw charge to swap
6952 * @page: page whose memsw charge to transfer
6953 * @entry: swap entry to move the charge to
6955 * Transfer the memsw charge of @page to @entry.
6957 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
6959 struct mem_cgroup
*memcg
, *swap_memcg
;
6960 unsigned int nr_entries
;
6961 unsigned short oldid
;
6963 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6964 VM_BUG_ON_PAGE(page_count(page
), page
);
6966 if (!do_memsw_account())
6969 memcg
= page
->mem_cgroup
;
6971 /* Readahead page, never charged */
6976 * In case the memcg owning these pages has been offlined and doesn't
6977 * have an ID allocated to it anymore, charge the closest online
6978 * ancestor for the swap instead and transfer the memory+swap charge.
6980 swap_memcg
= mem_cgroup_id_get_online(memcg
);
6981 nr_entries
= hpage_nr_pages(page
);
6982 /* Get references for the tail pages, too */
6984 mem_cgroup_id_get_many(swap_memcg
, nr_entries
- 1);
6985 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
),
6987 VM_BUG_ON_PAGE(oldid
, page
);
6988 mod_memcg_state(swap_memcg
, MEMCG_SWAP
, nr_entries
);
6990 page
->mem_cgroup
= NULL
;
6992 if (!mem_cgroup_is_root(memcg
))
6993 page_counter_uncharge(&memcg
->memory
, nr_entries
);
6995 if (memcg
!= swap_memcg
) {
6996 if (!mem_cgroup_is_root(swap_memcg
))
6997 page_counter_charge(&swap_memcg
->memsw
, nr_entries
);
6998 page_counter_uncharge(&memcg
->memsw
, nr_entries
);
7002 * Interrupts should be disabled here because the caller holds the
7003 * i_pages lock which is taken with interrupts-off. It is
7004 * important here to have the interrupts disabled because it is the
7005 * only synchronisation we have for updating the per-CPU variables.
7007 VM_BUG_ON(!irqs_disabled());
7008 mem_cgroup_charge_statistics(memcg
, page
, PageTransHuge(page
),
7010 memcg_check_events(memcg
, page
);
7012 if (!mem_cgroup_is_root(memcg
))
7013 css_put_many(&memcg
->css
, nr_entries
);
7017 * mem_cgroup_try_charge_swap - try charging swap space for a page
7018 * @page: page being added to swap
7019 * @entry: swap entry to charge
7021 * Try to charge @page's memcg for the swap space at @entry.
7023 * Returns 0 on success, -ENOMEM on failure.
7025 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
7027 unsigned int nr_pages
= hpage_nr_pages(page
);
7028 struct page_counter
*counter
;
7029 struct mem_cgroup
*memcg
;
7030 unsigned short oldid
;
7032 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) || !do_swap_account
)
7035 memcg
= page
->mem_cgroup
;
7037 /* Readahead page, never charged */
7042 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7046 memcg
= mem_cgroup_id_get_online(memcg
);
7048 if (!mem_cgroup_is_root(memcg
) &&
7049 !page_counter_try_charge(&memcg
->swap
, nr_pages
, &counter
)) {
7050 memcg_memory_event(memcg
, MEMCG_SWAP_MAX
);
7051 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7052 mem_cgroup_id_put(memcg
);
7056 /* Get references for the tail pages, too */
7058 mem_cgroup_id_get_many(memcg
, nr_pages
- 1);
7059 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
), nr_pages
);
7060 VM_BUG_ON_PAGE(oldid
, page
);
7061 mod_memcg_state(memcg
, MEMCG_SWAP
, nr_pages
);
7067 * mem_cgroup_uncharge_swap - uncharge swap space
7068 * @entry: swap entry to uncharge
7069 * @nr_pages: the amount of swap space to uncharge
7071 void mem_cgroup_uncharge_swap(swp_entry_t entry
, unsigned int nr_pages
)
7073 struct mem_cgroup
*memcg
;
7076 if (!do_swap_account
)
7079 id
= swap_cgroup_record(entry
, 0, nr_pages
);
7081 memcg
= mem_cgroup_from_id(id
);
7083 if (!mem_cgroup_is_root(memcg
)) {
7084 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7085 page_counter_uncharge(&memcg
->swap
, nr_pages
);
7087 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
7089 mod_memcg_state(memcg
, MEMCG_SWAP
, -nr_pages
);
7090 mem_cgroup_id_put_many(memcg
, nr_pages
);
7095 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
7097 long nr_swap_pages
= get_nr_swap_pages();
7099 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7100 return nr_swap_pages
;
7101 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
7102 nr_swap_pages
= min_t(long, nr_swap_pages
,
7103 READ_ONCE(memcg
->swap
.max
) -
7104 page_counter_read(&memcg
->swap
));
7105 return nr_swap_pages
;
7108 bool mem_cgroup_swap_full(struct page
*page
)
7110 struct mem_cgroup
*memcg
;
7112 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
7116 if (!do_swap_account
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7119 memcg
= page
->mem_cgroup
;
7123 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
7124 if (page_counter_read(&memcg
->swap
) * 2 >= memcg
->swap
.max
)
7130 /* for remember boot option*/
7131 #ifdef CONFIG_MEMCG_SWAP_ENABLED
7132 static int really_do_swap_account __initdata
= 1;
7134 static int really_do_swap_account __initdata
;
7137 static int __init
enable_swap_account(char *s
)
7139 if (!strcmp(s
, "1"))
7140 really_do_swap_account
= 1;
7141 else if (!strcmp(s
, "0"))
7142 really_do_swap_account
= 0;
7145 __setup("swapaccount=", enable_swap_account
);
7147 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
7150 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7152 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
7155 static int swap_max_show(struct seq_file
*m
, void *v
)
7157 return seq_puts_memcg_tunable(m
,
7158 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.max
));
7161 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
7162 char *buf
, size_t nbytes
, loff_t off
)
7164 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7168 buf
= strstrip(buf
);
7169 err
= page_counter_memparse(buf
, "max", &max
);
7173 xchg(&memcg
->swap
.max
, max
);
7178 static int swap_events_show(struct seq_file
*m
, void *v
)
7180 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
7182 seq_printf(m
, "max %lu\n",
7183 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_MAX
]));
7184 seq_printf(m
, "fail %lu\n",
7185 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_FAIL
]));
7190 static struct cftype swap_files
[] = {
7192 .name
= "swap.current",
7193 .flags
= CFTYPE_NOT_ON_ROOT
,
7194 .read_u64
= swap_current_read
,
7198 .flags
= CFTYPE_NOT_ON_ROOT
,
7199 .seq_show
= swap_max_show
,
7200 .write
= swap_max_write
,
7203 .name
= "swap.events",
7204 .flags
= CFTYPE_NOT_ON_ROOT
,
7205 .file_offset
= offsetof(struct mem_cgroup
, swap_events_file
),
7206 .seq_show
= swap_events_show
,
7211 static struct cftype memsw_cgroup_files
[] = {
7213 .name
= "memsw.usage_in_bytes",
7214 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
7215 .read_u64
= mem_cgroup_read_u64
,
7218 .name
= "memsw.max_usage_in_bytes",
7219 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
7220 .write
= mem_cgroup_reset
,
7221 .read_u64
= mem_cgroup_read_u64
,
7224 .name
= "memsw.limit_in_bytes",
7225 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
7226 .write
= mem_cgroup_write
,
7227 .read_u64
= mem_cgroup_read_u64
,
7230 .name
= "memsw.failcnt",
7231 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
7232 .write
= mem_cgroup_reset
,
7233 .read_u64
= mem_cgroup_read_u64
,
7235 { }, /* terminate */
7238 static int __init
mem_cgroup_swap_init(void)
7240 if (!mem_cgroup_disabled() && really_do_swap_account
) {
7241 do_swap_account
= 1;
7242 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
,
7244 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
,
7245 memsw_cgroup_files
));
7249 subsys_initcall(mem_cgroup_swap_init
);
7251 #endif /* CONFIG_MEMCG_SWAP */