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 bool cgroup_memory_noswap __read_mostly
;
88 #define cgroup_memory_noswap 1
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
) && !cgroup_memory_noswap
;
101 #define THRESHOLDS_EVENTS_TARGET 128
102 #define SOFTLIMIT_EVENTS_TARGET 1024
105 * Cgroups above their limits are maintained in a RB-Tree, independent of
106 * their hierarchy representation
109 struct mem_cgroup_tree_per_node
{
110 struct rb_root rb_root
;
111 struct rb_node
*rb_rightmost
;
115 struct mem_cgroup_tree
{
116 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
119 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
122 struct mem_cgroup_eventfd_list
{
123 struct list_head list
;
124 struct eventfd_ctx
*eventfd
;
128 * cgroup_event represents events which userspace want to receive.
130 struct mem_cgroup_event
{
132 * memcg which the event belongs to.
134 struct mem_cgroup
*memcg
;
136 * eventfd to signal userspace about the event.
138 struct eventfd_ctx
*eventfd
;
140 * Each of these stored in a list by the cgroup.
142 struct list_head list
;
144 * register_event() callback will be used to add new userspace
145 * waiter for changes related to this event. Use eventfd_signal()
146 * on eventfd to send notification to userspace.
148 int (*register_event
)(struct mem_cgroup
*memcg
,
149 struct eventfd_ctx
*eventfd
, const char *args
);
151 * unregister_event() callback will be called when userspace closes
152 * the eventfd or on cgroup removing. This callback must be set,
153 * if you want provide notification functionality.
155 void (*unregister_event
)(struct mem_cgroup
*memcg
,
156 struct eventfd_ctx
*eventfd
);
158 * All fields below needed to unregister event when
159 * userspace closes eventfd.
162 wait_queue_head_t
*wqh
;
163 wait_queue_entry_t wait
;
164 struct work_struct remove
;
167 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
168 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
170 /* Stuffs for move charges at task migration. */
172 * Types of charges to be moved.
174 #define MOVE_ANON 0x1U
175 #define MOVE_FILE 0x2U
176 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
178 /* "mc" and its members are protected by cgroup_mutex */
179 static struct move_charge_struct
{
180 spinlock_t lock
; /* for from, to */
181 struct mm_struct
*mm
;
182 struct mem_cgroup
*from
;
183 struct mem_cgroup
*to
;
185 unsigned long precharge
;
186 unsigned long moved_charge
;
187 unsigned long moved_swap
;
188 struct task_struct
*moving_task
; /* a task moving charges */
189 wait_queue_head_t waitq
; /* a waitq for other context */
191 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
192 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
196 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
197 * limit reclaim to prevent infinite loops, if they ever occur.
199 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
200 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
203 MEM_CGROUP_CHARGE_TYPE_CACHE
= 0,
204 MEM_CGROUP_CHARGE_TYPE_ANON
,
205 MEM_CGROUP_CHARGE_TYPE_SWAPOUT
, /* for accounting swapcache */
206 MEM_CGROUP_CHARGE_TYPE_DROP
, /* a page was unused swap cache */
210 /* for encoding cft->private value on file */
219 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
220 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
221 #define MEMFILE_ATTR(val) ((val) & 0xffff)
222 /* Used for OOM nofiier */
223 #define OOM_CONTROL (0)
226 * Iteration constructs for visiting all cgroups (under a tree). If
227 * loops are exited prematurely (break), mem_cgroup_iter_break() must
228 * be used for reference counting.
230 #define for_each_mem_cgroup_tree(iter, root) \
231 for (iter = mem_cgroup_iter(root, NULL, NULL); \
233 iter = mem_cgroup_iter(root, iter, NULL))
235 #define for_each_mem_cgroup(iter) \
236 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
238 iter = mem_cgroup_iter(NULL, iter, NULL))
240 static inline bool should_force_charge(void)
242 return tsk_is_oom_victim(current
) || fatal_signal_pending(current
) ||
243 (current
->flags
& PF_EXITING
);
246 /* Some nice accessors for the vmpressure. */
247 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
250 memcg
= root_mem_cgroup
;
251 return &memcg
->vmpressure
;
254 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
256 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
259 #ifdef CONFIG_MEMCG_KMEM
261 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
262 * The main reason for not using cgroup id for this:
263 * this works better in sparse environments, where we have a lot of memcgs,
264 * but only a few kmem-limited. Or also, if we have, for instance, 200
265 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
266 * 200 entry array for that.
268 * The current size of the caches array is stored in memcg_nr_cache_ids. It
269 * will double each time we have to increase it.
271 static DEFINE_IDA(memcg_cache_ida
);
272 int memcg_nr_cache_ids
;
274 /* Protects memcg_nr_cache_ids */
275 static DECLARE_RWSEM(memcg_cache_ids_sem
);
277 void memcg_get_cache_ids(void)
279 down_read(&memcg_cache_ids_sem
);
282 void memcg_put_cache_ids(void)
284 up_read(&memcg_cache_ids_sem
);
288 * MIN_SIZE is different than 1, because we would like to avoid going through
289 * the alloc/free process all the time. In a small machine, 4 kmem-limited
290 * cgroups is a reasonable guess. In the future, it could be a parameter or
291 * tunable, but that is strictly not necessary.
293 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
294 * this constant directly from cgroup, but it is understandable that this is
295 * better kept as an internal representation in cgroup.c. In any case, the
296 * cgrp_id space is not getting any smaller, and we don't have to necessarily
297 * increase ours as well if it increases.
299 #define MEMCG_CACHES_MIN_SIZE 4
300 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
303 * A lot of the calls to the cache allocation functions are expected to be
304 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
305 * conditional to this static branch, we'll have to allow modules that does
306 * kmem_cache_alloc and the such to see this symbol as well
308 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
309 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
311 struct workqueue_struct
*memcg_kmem_cache_wq
;
314 static int memcg_shrinker_map_size
;
315 static DEFINE_MUTEX(memcg_shrinker_map_mutex
);
317 static void memcg_free_shrinker_map_rcu(struct rcu_head
*head
)
319 kvfree(container_of(head
, struct memcg_shrinker_map
, rcu
));
322 static int memcg_expand_one_shrinker_map(struct mem_cgroup
*memcg
,
323 int size
, int old_size
)
325 struct memcg_shrinker_map
*new, *old
;
328 lockdep_assert_held(&memcg_shrinker_map_mutex
);
331 old
= rcu_dereference_protected(
332 mem_cgroup_nodeinfo(memcg
, nid
)->shrinker_map
, true);
333 /* Not yet online memcg */
337 new = kvmalloc_node(sizeof(*new) + size
, GFP_KERNEL
, nid
);
341 /* Set all old bits, clear all new bits */
342 memset(new->map
, (int)0xff, old_size
);
343 memset((void *)new->map
+ old_size
, 0, size
- old_size
);
345 rcu_assign_pointer(memcg
->nodeinfo
[nid
]->shrinker_map
, new);
346 call_rcu(&old
->rcu
, memcg_free_shrinker_map_rcu
);
352 static void memcg_free_shrinker_maps(struct mem_cgroup
*memcg
)
354 struct mem_cgroup_per_node
*pn
;
355 struct memcg_shrinker_map
*map
;
358 if (mem_cgroup_is_root(memcg
))
362 pn
= mem_cgroup_nodeinfo(memcg
, nid
);
363 map
= rcu_dereference_protected(pn
->shrinker_map
, true);
366 rcu_assign_pointer(pn
->shrinker_map
, NULL
);
370 static int memcg_alloc_shrinker_maps(struct mem_cgroup
*memcg
)
372 struct memcg_shrinker_map
*map
;
373 int nid
, size
, ret
= 0;
375 if (mem_cgroup_is_root(memcg
))
378 mutex_lock(&memcg_shrinker_map_mutex
);
379 size
= memcg_shrinker_map_size
;
381 map
= kvzalloc_node(sizeof(*map
) + size
, GFP_KERNEL
, nid
);
383 memcg_free_shrinker_maps(memcg
);
387 rcu_assign_pointer(memcg
->nodeinfo
[nid
]->shrinker_map
, map
);
389 mutex_unlock(&memcg_shrinker_map_mutex
);
394 int memcg_expand_shrinker_maps(int new_id
)
396 int size
, old_size
, ret
= 0;
397 struct mem_cgroup
*memcg
;
399 size
= DIV_ROUND_UP(new_id
+ 1, BITS_PER_LONG
) * sizeof(unsigned long);
400 old_size
= memcg_shrinker_map_size
;
401 if (size
<= old_size
)
404 mutex_lock(&memcg_shrinker_map_mutex
);
405 if (!root_mem_cgroup
)
408 for_each_mem_cgroup(memcg
) {
409 if (mem_cgroup_is_root(memcg
))
411 ret
= memcg_expand_one_shrinker_map(memcg
, size
, old_size
);
413 mem_cgroup_iter_break(NULL
, memcg
);
419 memcg_shrinker_map_size
= size
;
420 mutex_unlock(&memcg_shrinker_map_mutex
);
424 void memcg_set_shrinker_bit(struct mem_cgroup
*memcg
, int nid
, int shrinker_id
)
426 if (shrinker_id
>= 0 && memcg
&& !mem_cgroup_is_root(memcg
)) {
427 struct memcg_shrinker_map
*map
;
430 map
= rcu_dereference(memcg
->nodeinfo
[nid
]->shrinker_map
);
431 /* Pairs with smp mb in shrink_slab() */
432 smp_mb__before_atomic();
433 set_bit(shrinker_id
, map
->map
);
439 * mem_cgroup_css_from_page - css of the memcg associated with a page
440 * @page: page of interest
442 * If memcg is bound to the default hierarchy, css of the memcg associated
443 * with @page is returned. The returned css remains associated with @page
444 * until it is released.
446 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
449 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
451 struct mem_cgroup
*memcg
;
453 memcg
= page
->mem_cgroup
;
455 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
456 memcg
= root_mem_cgroup
;
462 * page_cgroup_ino - return inode number of the memcg a page is charged to
465 * Look up the closest online ancestor of the memory cgroup @page is charged to
466 * and return its inode number or 0 if @page is not charged to any cgroup. It
467 * is safe to call this function without holding a reference to @page.
469 * Note, this function is inherently racy, because there is nothing to prevent
470 * the cgroup inode from getting torn down and potentially reallocated a moment
471 * after page_cgroup_ino() returns, so it only should be used by callers that
472 * do not care (such as procfs interfaces).
474 ino_t
page_cgroup_ino(struct page
*page
)
476 struct mem_cgroup
*memcg
;
477 unsigned long ino
= 0;
480 if (PageSlab(page
) && !PageTail(page
))
481 memcg
= memcg_from_slab_page(page
);
483 memcg
= READ_ONCE(page
->mem_cgroup
);
484 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
485 memcg
= parent_mem_cgroup(memcg
);
487 ino
= cgroup_ino(memcg
->css
.cgroup
);
492 static struct mem_cgroup_per_node
*
493 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
495 int nid
= page_to_nid(page
);
497 return memcg
->nodeinfo
[nid
];
500 static struct mem_cgroup_tree_per_node
*
501 soft_limit_tree_node(int nid
)
503 return soft_limit_tree
.rb_tree_per_node
[nid
];
506 static struct mem_cgroup_tree_per_node
*
507 soft_limit_tree_from_page(struct page
*page
)
509 int nid
= page_to_nid(page
);
511 return soft_limit_tree
.rb_tree_per_node
[nid
];
514 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
515 struct mem_cgroup_tree_per_node
*mctz
,
516 unsigned long new_usage_in_excess
)
518 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
519 struct rb_node
*parent
= NULL
;
520 struct mem_cgroup_per_node
*mz_node
;
521 bool rightmost
= true;
526 mz
->usage_in_excess
= new_usage_in_excess
;
527 if (!mz
->usage_in_excess
)
531 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
533 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
) {
539 * We can't avoid mem cgroups that are over their soft
540 * limit by the same amount
542 else if (mz
->usage_in_excess
>= mz_node
->usage_in_excess
)
547 mctz
->rb_rightmost
= &mz
->tree_node
;
549 rb_link_node(&mz
->tree_node
, parent
, p
);
550 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
554 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
555 struct mem_cgroup_tree_per_node
*mctz
)
560 if (&mz
->tree_node
== mctz
->rb_rightmost
)
561 mctz
->rb_rightmost
= rb_prev(&mz
->tree_node
);
563 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
567 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
568 struct mem_cgroup_tree_per_node
*mctz
)
572 spin_lock_irqsave(&mctz
->lock
, flags
);
573 __mem_cgroup_remove_exceeded(mz
, mctz
);
574 spin_unlock_irqrestore(&mctz
->lock
, flags
);
577 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
579 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
580 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
581 unsigned long excess
= 0;
583 if (nr_pages
> soft_limit
)
584 excess
= nr_pages
- soft_limit
;
589 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
591 unsigned long excess
;
592 struct mem_cgroup_per_node
*mz
;
593 struct mem_cgroup_tree_per_node
*mctz
;
595 mctz
= soft_limit_tree_from_page(page
);
599 * Necessary to update all ancestors when hierarchy is used.
600 * because their event counter is not touched.
602 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
603 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
604 excess
= soft_limit_excess(memcg
);
606 * We have to update the tree if mz is on RB-tree or
607 * mem is over its softlimit.
609 if (excess
|| mz
->on_tree
) {
612 spin_lock_irqsave(&mctz
->lock
, flags
);
613 /* if on-tree, remove it */
615 __mem_cgroup_remove_exceeded(mz
, mctz
);
617 * Insert again. mz->usage_in_excess will be updated.
618 * If excess is 0, no tree ops.
620 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
621 spin_unlock_irqrestore(&mctz
->lock
, flags
);
626 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
628 struct mem_cgroup_tree_per_node
*mctz
;
629 struct mem_cgroup_per_node
*mz
;
633 mz
= mem_cgroup_nodeinfo(memcg
, nid
);
634 mctz
= soft_limit_tree_node(nid
);
636 mem_cgroup_remove_exceeded(mz
, mctz
);
640 static struct mem_cgroup_per_node
*
641 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
643 struct mem_cgroup_per_node
*mz
;
647 if (!mctz
->rb_rightmost
)
648 goto done
; /* Nothing to reclaim from */
650 mz
= rb_entry(mctz
->rb_rightmost
,
651 struct mem_cgroup_per_node
, tree_node
);
653 * Remove the node now but someone else can add it back,
654 * we will to add it back at the end of reclaim to its correct
655 * position in the tree.
657 __mem_cgroup_remove_exceeded(mz
, mctz
);
658 if (!soft_limit_excess(mz
->memcg
) ||
659 !css_tryget(&mz
->memcg
->css
))
665 static struct mem_cgroup_per_node
*
666 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
668 struct mem_cgroup_per_node
*mz
;
670 spin_lock_irq(&mctz
->lock
);
671 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
672 spin_unlock_irq(&mctz
->lock
);
677 * __mod_memcg_state - update cgroup memory statistics
678 * @memcg: the memory cgroup
679 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
680 * @val: delta to add to the counter, can be negative
682 void __mod_memcg_state(struct mem_cgroup
*memcg
, int idx
, int val
)
686 if (mem_cgroup_disabled())
689 x
= val
+ __this_cpu_read(memcg
->vmstats_percpu
->stat
[idx
]);
690 if (unlikely(abs(x
) > MEMCG_CHARGE_BATCH
)) {
691 struct mem_cgroup
*mi
;
694 * Batch local counters to keep them in sync with
695 * the hierarchical ones.
697 __this_cpu_add(memcg
->vmstats_local
->stat
[idx
], x
);
698 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
699 atomic_long_add(x
, &mi
->vmstats
[idx
]);
702 __this_cpu_write(memcg
->vmstats_percpu
->stat
[idx
], x
);
705 static struct mem_cgroup_per_node
*
706 parent_nodeinfo(struct mem_cgroup_per_node
*pn
, int nid
)
708 struct mem_cgroup
*parent
;
710 parent
= parent_mem_cgroup(pn
->memcg
);
713 return mem_cgroup_nodeinfo(parent
, nid
);
717 * __mod_lruvec_state - update lruvec memory statistics
718 * @lruvec: the lruvec
719 * @idx: the stat item
720 * @val: delta to add to the counter, can be negative
722 * The lruvec is the intersection of the NUMA node and a cgroup. This
723 * function updates the all three counters that are affected by a
724 * change of state at this level: per-node, per-cgroup, per-lruvec.
726 void __mod_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
729 pg_data_t
*pgdat
= lruvec_pgdat(lruvec
);
730 struct mem_cgroup_per_node
*pn
;
731 struct mem_cgroup
*memcg
;
735 __mod_node_page_state(pgdat
, idx
, val
);
737 if (mem_cgroup_disabled())
740 pn
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
744 __mod_memcg_state(memcg
, idx
, val
);
747 __this_cpu_add(pn
->lruvec_stat_local
->count
[idx
], val
);
749 x
= val
+ __this_cpu_read(pn
->lruvec_stat_cpu
->count
[idx
]);
750 if (unlikely(abs(x
) > MEMCG_CHARGE_BATCH
)) {
751 struct mem_cgroup_per_node
*pi
;
753 for (pi
= pn
; pi
; pi
= parent_nodeinfo(pi
, pgdat
->node_id
))
754 atomic_long_add(x
, &pi
->lruvec_stat
[idx
]);
757 __this_cpu_write(pn
->lruvec_stat_cpu
->count
[idx
], x
);
760 void __mod_lruvec_slab_state(void *p
, enum node_stat_item idx
, int val
)
762 pg_data_t
*pgdat
= page_pgdat(virt_to_page(p
));
763 struct mem_cgroup
*memcg
;
764 struct lruvec
*lruvec
;
767 memcg
= mem_cgroup_from_obj(p
);
769 /* Untracked pages have no memcg, no lruvec. Update only the node */
770 if (!memcg
|| memcg
== root_mem_cgroup
) {
771 __mod_node_page_state(pgdat
, idx
, val
);
773 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
774 __mod_lruvec_state(lruvec
, idx
, val
);
779 void mod_memcg_obj_state(void *p
, int idx
, int val
)
781 struct mem_cgroup
*memcg
;
784 memcg
= mem_cgroup_from_obj(p
);
786 mod_memcg_state(memcg
, idx
, val
);
791 * __count_memcg_events - account VM events in a cgroup
792 * @memcg: the memory cgroup
793 * @idx: the event item
794 * @count: the number of events that occured
796 void __count_memcg_events(struct mem_cgroup
*memcg
, enum vm_event_item idx
,
801 if (mem_cgroup_disabled())
804 x
= count
+ __this_cpu_read(memcg
->vmstats_percpu
->events
[idx
]);
805 if (unlikely(x
> MEMCG_CHARGE_BATCH
)) {
806 struct mem_cgroup
*mi
;
809 * Batch local counters to keep them in sync with
810 * the hierarchical ones.
812 __this_cpu_add(memcg
->vmstats_local
->events
[idx
], x
);
813 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
814 atomic_long_add(x
, &mi
->vmevents
[idx
]);
817 __this_cpu_write(memcg
->vmstats_percpu
->events
[idx
], x
);
820 static unsigned long memcg_events(struct mem_cgroup
*memcg
, int event
)
822 return atomic_long_read(&memcg
->vmevents
[event
]);
825 static unsigned long memcg_events_local(struct mem_cgroup
*memcg
, int event
)
830 for_each_possible_cpu(cpu
)
831 x
+= per_cpu(memcg
->vmstats_local
->events
[event
], cpu
);
835 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
839 /* pagein of a big page is an event. So, ignore page size */
841 __count_memcg_events(memcg
, PGPGIN
, 1);
843 __count_memcg_events(memcg
, PGPGOUT
, 1);
844 nr_pages
= -nr_pages
; /* for event */
847 __this_cpu_add(memcg
->vmstats_percpu
->nr_page_events
, nr_pages
);
850 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
851 enum mem_cgroup_events_target target
)
853 unsigned long val
, next
;
855 val
= __this_cpu_read(memcg
->vmstats_percpu
->nr_page_events
);
856 next
= __this_cpu_read(memcg
->vmstats_percpu
->targets
[target
]);
857 /* from time_after() in jiffies.h */
858 if ((long)(next
- val
) < 0) {
860 case MEM_CGROUP_TARGET_THRESH
:
861 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
863 case MEM_CGROUP_TARGET_SOFTLIMIT
:
864 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
869 __this_cpu_write(memcg
->vmstats_percpu
->targets
[target
], next
);
876 * Check events in order.
879 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
881 /* threshold event is triggered in finer grain than soft limit */
882 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
883 MEM_CGROUP_TARGET_THRESH
))) {
886 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
887 MEM_CGROUP_TARGET_SOFTLIMIT
);
888 mem_cgroup_threshold(memcg
);
889 if (unlikely(do_softlimit
))
890 mem_cgroup_update_tree(memcg
, page
);
894 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
897 * mm_update_next_owner() may clear mm->owner to NULL
898 * if it races with swapoff, page migration, etc.
899 * So this can be called with p == NULL.
904 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
906 EXPORT_SYMBOL(mem_cgroup_from_task
);
909 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
910 * @mm: mm from which memcg should be extracted. It can be NULL.
912 * Obtain a reference on mm->memcg and returns it if successful. Otherwise
913 * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is
916 struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
918 struct mem_cgroup
*memcg
;
920 if (mem_cgroup_disabled())
926 * Page cache insertions can happen withou an
927 * actual mm context, e.g. during disk probing
928 * on boot, loopback IO, acct() writes etc.
931 memcg
= root_mem_cgroup
;
933 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
934 if (unlikely(!memcg
))
935 memcg
= root_mem_cgroup
;
937 } while (!css_tryget(&memcg
->css
));
941 EXPORT_SYMBOL(get_mem_cgroup_from_mm
);
944 * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
945 * @page: page from which memcg should be extracted.
947 * Obtain a reference on page->memcg and returns it if successful. Otherwise
948 * root_mem_cgroup is returned.
950 struct mem_cgroup
*get_mem_cgroup_from_page(struct page
*page
)
952 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
954 if (mem_cgroup_disabled())
958 /* Page should not get uncharged and freed memcg under us. */
959 if (!memcg
|| WARN_ON_ONCE(!css_tryget(&memcg
->css
)))
960 memcg
= root_mem_cgroup
;
964 EXPORT_SYMBOL(get_mem_cgroup_from_page
);
967 * If current->active_memcg is non-NULL, do not fallback to current->mm->memcg.
969 static __always_inline
struct mem_cgroup
*get_mem_cgroup_from_current(void)
971 if (unlikely(current
->active_memcg
)) {
972 struct mem_cgroup
*memcg
;
975 /* current->active_memcg must hold a ref. */
976 if (WARN_ON_ONCE(!css_tryget(¤t
->active_memcg
->css
)))
977 memcg
= root_mem_cgroup
;
979 memcg
= current
->active_memcg
;
983 return get_mem_cgroup_from_mm(current
->mm
);
987 * mem_cgroup_iter - iterate over memory cgroup hierarchy
988 * @root: hierarchy root
989 * @prev: previously returned memcg, NULL on first invocation
990 * @reclaim: cookie for shared reclaim walks, NULL for full walks
992 * Returns references to children of the hierarchy below @root, or
993 * @root itself, or %NULL after a full round-trip.
995 * Caller must pass the return value in @prev on subsequent
996 * invocations for reference counting, or use mem_cgroup_iter_break()
997 * to cancel a hierarchy walk before the round-trip is complete.
999 * Reclaimers can specify a node and a priority level in @reclaim to
1000 * divide up the memcgs in the hierarchy among all concurrent
1001 * reclaimers operating on the same node and priority.
1003 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
1004 struct mem_cgroup
*prev
,
1005 struct mem_cgroup_reclaim_cookie
*reclaim
)
1007 struct mem_cgroup_reclaim_iter
*uninitialized_var(iter
);
1008 struct cgroup_subsys_state
*css
= NULL
;
1009 struct mem_cgroup
*memcg
= NULL
;
1010 struct mem_cgroup
*pos
= NULL
;
1012 if (mem_cgroup_disabled())
1016 root
= root_mem_cgroup
;
1018 if (prev
&& !reclaim
)
1021 if (!root
->use_hierarchy
&& root
!= root_mem_cgroup
) {
1030 struct mem_cgroup_per_node
*mz
;
1032 mz
= mem_cgroup_nodeinfo(root
, reclaim
->pgdat
->node_id
);
1035 if (prev
&& reclaim
->generation
!= iter
->generation
)
1039 pos
= READ_ONCE(iter
->position
);
1040 if (!pos
|| css_tryget(&pos
->css
))
1043 * css reference reached zero, so iter->position will
1044 * be cleared by ->css_released. However, we should not
1045 * rely on this happening soon, because ->css_released
1046 * is called from a work queue, and by busy-waiting we
1047 * might block it. So we clear iter->position right
1050 (void)cmpxchg(&iter
->position
, pos
, NULL
);
1058 css
= css_next_descendant_pre(css
, &root
->css
);
1061 * Reclaimers share the hierarchy walk, and a
1062 * new one might jump in right at the end of
1063 * the hierarchy - make sure they see at least
1064 * one group and restart from the beginning.
1072 * Verify the css and acquire a reference. The root
1073 * is provided by the caller, so we know it's alive
1074 * and kicking, and don't take an extra reference.
1076 memcg
= mem_cgroup_from_css(css
);
1078 if (css
== &root
->css
)
1081 if (css_tryget(css
))
1089 * The position could have already been updated by a competing
1090 * thread, so check that the value hasn't changed since we read
1091 * it to avoid reclaiming from the same cgroup twice.
1093 (void)cmpxchg(&iter
->position
, pos
, memcg
);
1101 reclaim
->generation
= iter
->generation
;
1107 if (prev
&& prev
!= root
)
1108 css_put(&prev
->css
);
1114 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1115 * @root: hierarchy root
1116 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1118 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1119 struct mem_cgroup
*prev
)
1122 root
= root_mem_cgroup
;
1123 if (prev
&& prev
!= root
)
1124 css_put(&prev
->css
);
1127 static void __invalidate_reclaim_iterators(struct mem_cgroup
*from
,
1128 struct mem_cgroup
*dead_memcg
)
1130 struct mem_cgroup_reclaim_iter
*iter
;
1131 struct mem_cgroup_per_node
*mz
;
1134 for_each_node(nid
) {
1135 mz
= mem_cgroup_nodeinfo(from
, nid
);
1137 cmpxchg(&iter
->position
, dead_memcg
, NULL
);
1141 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
1143 struct mem_cgroup
*memcg
= dead_memcg
;
1144 struct mem_cgroup
*last
;
1147 __invalidate_reclaim_iterators(memcg
, dead_memcg
);
1149 } while ((memcg
= parent_mem_cgroup(memcg
)));
1152 * When cgruop1 non-hierarchy mode is used,
1153 * parent_mem_cgroup() does not walk all the way up to the
1154 * cgroup root (root_mem_cgroup). So we have to handle
1155 * dead_memcg from cgroup root separately.
1157 if (last
!= root_mem_cgroup
)
1158 __invalidate_reclaim_iterators(root_mem_cgroup
,
1163 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1164 * @memcg: hierarchy root
1165 * @fn: function to call for each task
1166 * @arg: argument passed to @fn
1168 * This function iterates over tasks attached to @memcg or to any of its
1169 * descendants and calls @fn for each task. If @fn returns a non-zero
1170 * value, the function breaks the iteration loop and returns the value.
1171 * Otherwise, it will iterate over all tasks and return 0.
1173 * This function must not be called for the root memory cgroup.
1175 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
1176 int (*fn
)(struct task_struct
*, void *), void *arg
)
1178 struct mem_cgroup
*iter
;
1181 BUG_ON(memcg
== root_mem_cgroup
);
1183 for_each_mem_cgroup_tree(iter
, memcg
) {
1184 struct css_task_iter it
;
1185 struct task_struct
*task
;
1187 css_task_iter_start(&iter
->css
, CSS_TASK_ITER_PROCS
, &it
);
1188 while (!ret
&& (task
= css_task_iter_next(&it
)))
1189 ret
= fn(task
, arg
);
1190 css_task_iter_end(&it
);
1192 mem_cgroup_iter_break(memcg
, iter
);
1200 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1202 * @pgdat: pgdat of the page
1204 * This function relies on page->mem_cgroup being stable - see the
1205 * access rules in commit_charge().
1207 struct lruvec
*mem_cgroup_page_lruvec(struct page
*page
, struct pglist_data
*pgdat
)
1209 struct mem_cgroup_per_node
*mz
;
1210 struct mem_cgroup
*memcg
;
1211 struct lruvec
*lruvec
;
1213 if (mem_cgroup_disabled()) {
1214 lruvec
= &pgdat
->__lruvec
;
1218 memcg
= page
->mem_cgroup
;
1220 * Swapcache readahead pages are added to the LRU - and
1221 * possibly migrated - before they are charged.
1224 memcg
= root_mem_cgroup
;
1226 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
1227 lruvec
= &mz
->lruvec
;
1230 * Since a node can be onlined after the mem_cgroup was created,
1231 * we have to be prepared to initialize lruvec->zone here;
1232 * and if offlined then reonlined, we need to reinitialize it.
1234 if (unlikely(lruvec
->pgdat
!= pgdat
))
1235 lruvec
->pgdat
= pgdat
;
1240 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1241 * @lruvec: mem_cgroup per zone lru vector
1242 * @lru: index of lru list the page is sitting on
1243 * @zid: zone id of the accounted pages
1244 * @nr_pages: positive when adding or negative when removing
1246 * This function must be called under lru_lock, just before a page is added
1247 * to or just after a page is removed from an lru list (that ordering being
1248 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1250 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1251 int zid
, int nr_pages
)
1253 struct mem_cgroup_per_node
*mz
;
1254 unsigned long *lru_size
;
1257 if (mem_cgroup_disabled())
1260 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1261 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1264 *lru_size
+= nr_pages
;
1267 if (WARN_ONCE(size
< 0,
1268 "%s(%p, %d, %d): lru_size %ld\n",
1269 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1275 *lru_size
+= nr_pages
;
1279 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1280 * @memcg: the memory cgroup
1282 * Returns the maximum amount of memory @mem can be charged with, in
1285 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1287 unsigned long margin
= 0;
1288 unsigned long count
;
1289 unsigned long limit
;
1291 count
= page_counter_read(&memcg
->memory
);
1292 limit
= READ_ONCE(memcg
->memory
.max
);
1294 margin
= limit
- count
;
1296 if (do_memsw_account()) {
1297 count
= page_counter_read(&memcg
->memsw
);
1298 limit
= READ_ONCE(memcg
->memsw
.max
);
1300 margin
= min(margin
, limit
- count
);
1309 * A routine for checking "mem" is under move_account() or not.
1311 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1312 * moving cgroups. This is for waiting at high-memory pressure
1315 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1317 struct mem_cgroup
*from
;
1318 struct mem_cgroup
*to
;
1321 * Unlike task_move routines, we access mc.to, mc.from not under
1322 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1324 spin_lock(&mc
.lock
);
1330 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1331 mem_cgroup_is_descendant(to
, memcg
);
1333 spin_unlock(&mc
.lock
);
1337 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1339 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1340 if (mem_cgroup_under_move(memcg
)) {
1342 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1343 /* moving charge context might have finished. */
1346 finish_wait(&mc
.waitq
, &wait
);
1353 static char *memory_stat_format(struct mem_cgroup
*memcg
)
1358 seq_buf_init(&s
, kmalloc(PAGE_SIZE
, GFP_KERNEL
), PAGE_SIZE
);
1363 * Provide statistics on the state of the memory subsystem as
1364 * well as cumulative event counters that show past behavior.
1366 * This list is ordered following a combination of these gradients:
1367 * 1) generic big picture -> specifics and details
1368 * 2) reflecting userspace activity -> reflecting kernel heuristics
1370 * Current memory state:
1373 seq_buf_printf(&s
, "anon %llu\n",
1374 (u64
)memcg_page_state(memcg
, NR_ANON_MAPPED
) *
1376 seq_buf_printf(&s
, "file %llu\n",
1377 (u64
)memcg_page_state(memcg
, NR_FILE_PAGES
) *
1379 seq_buf_printf(&s
, "kernel_stack %llu\n",
1380 (u64
)memcg_page_state(memcg
, MEMCG_KERNEL_STACK_KB
) *
1382 seq_buf_printf(&s
, "slab %llu\n",
1383 (u64
)(memcg_page_state(memcg
, NR_SLAB_RECLAIMABLE
) +
1384 memcg_page_state(memcg
, NR_SLAB_UNRECLAIMABLE
)) *
1386 seq_buf_printf(&s
, "sock %llu\n",
1387 (u64
)memcg_page_state(memcg
, MEMCG_SOCK
) *
1390 seq_buf_printf(&s
, "shmem %llu\n",
1391 (u64
)memcg_page_state(memcg
, NR_SHMEM
) *
1393 seq_buf_printf(&s
, "file_mapped %llu\n",
1394 (u64
)memcg_page_state(memcg
, NR_FILE_MAPPED
) *
1396 seq_buf_printf(&s
, "file_dirty %llu\n",
1397 (u64
)memcg_page_state(memcg
, NR_FILE_DIRTY
) *
1399 seq_buf_printf(&s
, "file_writeback %llu\n",
1400 (u64
)memcg_page_state(memcg
, NR_WRITEBACK
) *
1403 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1404 seq_buf_printf(&s
, "anon_thp %llu\n",
1405 (u64
)memcg_page_state(memcg
, NR_ANON_THPS
) *
1409 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
1410 seq_buf_printf(&s
, "%s %llu\n", lru_list_name(i
),
1411 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
1414 seq_buf_printf(&s
, "slab_reclaimable %llu\n",
1415 (u64
)memcg_page_state(memcg
, NR_SLAB_RECLAIMABLE
) *
1417 seq_buf_printf(&s
, "slab_unreclaimable %llu\n",
1418 (u64
)memcg_page_state(memcg
, NR_SLAB_UNRECLAIMABLE
) *
1421 /* Accumulated memory events */
1423 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGFAULT
),
1424 memcg_events(memcg
, PGFAULT
));
1425 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGMAJFAULT
),
1426 memcg_events(memcg
, PGMAJFAULT
));
1428 seq_buf_printf(&s
, "workingset_refault %lu\n",
1429 memcg_page_state(memcg
, WORKINGSET_REFAULT
));
1430 seq_buf_printf(&s
, "workingset_activate %lu\n",
1431 memcg_page_state(memcg
, WORKINGSET_ACTIVATE
));
1432 seq_buf_printf(&s
, "workingset_restore %lu\n",
1433 memcg_page_state(memcg
, WORKINGSET_RESTORE
));
1434 seq_buf_printf(&s
, "workingset_nodereclaim %lu\n",
1435 memcg_page_state(memcg
, WORKINGSET_NODERECLAIM
));
1437 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGREFILL
),
1438 memcg_events(memcg
, PGREFILL
));
1439 seq_buf_printf(&s
, "pgscan %lu\n",
1440 memcg_events(memcg
, PGSCAN_KSWAPD
) +
1441 memcg_events(memcg
, PGSCAN_DIRECT
));
1442 seq_buf_printf(&s
, "pgsteal %lu\n",
1443 memcg_events(memcg
, PGSTEAL_KSWAPD
) +
1444 memcg_events(memcg
, PGSTEAL_DIRECT
));
1445 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGACTIVATE
),
1446 memcg_events(memcg
, PGACTIVATE
));
1447 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGDEACTIVATE
),
1448 memcg_events(memcg
, PGDEACTIVATE
));
1449 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREE
),
1450 memcg_events(memcg
, PGLAZYFREE
));
1451 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREED
),
1452 memcg_events(memcg
, PGLAZYFREED
));
1454 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1455 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC
),
1456 memcg_events(memcg
, THP_FAULT_ALLOC
));
1457 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC
),
1458 memcg_events(memcg
, THP_COLLAPSE_ALLOC
));
1459 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1461 /* The above should easily fit into one page */
1462 WARN_ON_ONCE(seq_buf_has_overflowed(&s
));
1467 #define K(x) ((x) << (PAGE_SHIFT-10))
1469 * mem_cgroup_print_oom_context: Print OOM information relevant to
1470 * memory controller.
1471 * @memcg: The memory cgroup that went over limit
1472 * @p: Task that is going to be killed
1474 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1477 void mem_cgroup_print_oom_context(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1482 pr_cont(",oom_memcg=");
1483 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1485 pr_cont(",global_oom");
1487 pr_cont(",task_memcg=");
1488 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1494 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1495 * memory controller.
1496 * @memcg: The memory cgroup that went over limit
1498 void mem_cgroup_print_oom_meminfo(struct mem_cgroup
*memcg
)
1502 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1503 K((u64
)page_counter_read(&memcg
->memory
)),
1504 K((u64
)READ_ONCE(memcg
->memory
.max
)), memcg
->memory
.failcnt
);
1505 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1506 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1507 K((u64
)page_counter_read(&memcg
->swap
)),
1508 K((u64
)READ_ONCE(memcg
->swap
.max
)), memcg
->swap
.failcnt
);
1510 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1511 K((u64
)page_counter_read(&memcg
->memsw
)),
1512 K((u64
)memcg
->memsw
.max
), memcg
->memsw
.failcnt
);
1513 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1514 K((u64
)page_counter_read(&memcg
->kmem
)),
1515 K((u64
)memcg
->kmem
.max
), memcg
->kmem
.failcnt
);
1518 pr_info("Memory cgroup stats for ");
1519 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1521 buf
= memory_stat_format(memcg
);
1529 * Return the memory (and swap, if configured) limit for a memcg.
1531 unsigned long mem_cgroup_get_max(struct mem_cgroup
*memcg
)
1535 max
= READ_ONCE(memcg
->memory
.max
);
1536 if (mem_cgroup_swappiness(memcg
)) {
1537 unsigned long memsw_max
;
1538 unsigned long swap_max
;
1540 memsw_max
= memcg
->memsw
.max
;
1541 swap_max
= READ_ONCE(memcg
->swap
.max
);
1542 swap_max
= min(swap_max
, (unsigned long)total_swap_pages
);
1543 max
= min(max
+ swap_max
, memsw_max
);
1548 unsigned long mem_cgroup_size(struct mem_cgroup
*memcg
)
1550 return page_counter_read(&memcg
->memory
);
1553 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1556 struct oom_control oc
= {
1560 .gfp_mask
= gfp_mask
,
1565 if (mutex_lock_killable(&oom_lock
))
1568 * A few threads which were not waiting at mutex_lock_killable() can
1569 * fail to bail out. Therefore, check again after holding oom_lock.
1571 ret
= should_force_charge() || out_of_memory(&oc
);
1572 mutex_unlock(&oom_lock
);
1576 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1579 unsigned long *total_scanned
)
1581 struct mem_cgroup
*victim
= NULL
;
1584 unsigned long excess
;
1585 unsigned long nr_scanned
;
1586 struct mem_cgroup_reclaim_cookie reclaim
= {
1590 excess
= soft_limit_excess(root_memcg
);
1593 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1598 * If we have not been able to reclaim
1599 * anything, it might because there are
1600 * no reclaimable pages under this hierarchy
1605 * We want to do more targeted reclaim.
1606 * excess >> 2 is not to excessive so as to
1607 * reclaim too much, nor too less that we keep
1608 * coming back to reclaim from this cgroup
1610 if (total
>= (excess
>> 2) ||
1611 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1616 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1617 pgdat
, &nr_scanned
);
1618 *total_scanned
+= nr_scanned
;
1619 if (!soft_limit_excess(root_memcg
))
1622 mem_cgroup_iter_break(root_memcg
, victim
);
1626 #ifdef CONFIG_LOCKDEP
1627 static struct lockdep_map memcg_oom_lock_dep_map
= {
1628 .name
= "memcg_oom_lock",
1632 static DEFINE_SPINLOCK(memcg_oom_lock
);
1635 * Check OOM-Killer is already running under our hierarchy.
1636 * If someone is running, return false.
1638 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1640 struct mem_cgroup
*iter
, *failed
= NULL
;
1642 spin_lock(&memcg_oom_lock
);
1644 for_each_mem_cgroup_tree(iter
, memcg
) {
1645 if (iter
->oom_lock
) {
1647 * this subtree of our hierarchy is already locked
1648 * so we cannot give a lock.
1651 mem_cgroup_iter_break(memcg
, iter
);
1654 iter
->oom_lock
= true;
1659 * OK, we failed to lock the whole subtree so we have
1660 * to clean up what we set up to the failing subtree
1662 for_each_mem_cgroup_tree(iter
, memcg
) {
1663 if (iter
== failed
) {
1664 mem_cgroup_iter_break(memcg
, iter
);
1667 iter
->oom_lock
= false;
1670 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1672 spin_unlock(&memcg_oom_lock
);
1677 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1679 struct mem_cgroup
*iter
;
1681 spin_lock(&memcg_oom_lock
);
1682 mutex_release(&memcg_oom_lock_dep_map
, _RET_IP_
);
1683 for_each_mem_cgroup_tree(iter
, memcg
)
1684 iter
->oom_lock
= false;
1685 spin_unlock(&memcg_oom_lock
);
1688 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1690 struct mem_cgroup
*iter
;
1692 spin_lock(&memcg_oom_lock
);
1693 for_each_mem_cgroup_tree(iter
, memcg
)
1695 spin_unlock(&memcg_oom_lock
);
1698 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1700 struct mem_cgroup
*iter
;
1703 * When a new child is created while the hierarchy is under oom,
1704 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1706 spin_lock(&memcg_oom_lock
);
1707 for_each_mem_cgroup_tree(iter
, memcg
)
1708 if (iter
->under_oom
> 0)
1710 spin_unlock(&memcg_oom_lock
);
1713 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1715 struct oom_wait_info
{
1716 struct mem_cgroup
*memcg
;
1717 wait_queue_entry_t wait
;
1720 static int memcg_oom_wake_function(wait_queue_entry_t
*wait
,
1721 unsigned mode
, int sync
, void *arg
)
1723 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1724 struct mem_cgroup
*oom_wait_memcg
;
1725 struct oom_wait_info
*oom_wait_info
;
1727 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1728 oom_wait_memcg
= oom_wait_info
->memcg
;
1730 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1731 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1733 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1736 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1739 * For the following lockless ->under_oom test, the only required
1740 * guarantee is that it must see the state asserted by an OOM when
1741 * this function is called as a result of userland actions
1742 * triggered by the notification of the OOM. This is trivially
1743 * achieved by invoking mem_cgroup_mark_under_oom() before
1744 * triggering notification.
1746 if (memcg
&& memcg
->under_oom
)
1747 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1757 static enum oom_status
mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1759 enum oom_status ret
;
1762 if (order
> PAGE_ALLOC_COSTLY_ORDER
)
1765 memcg_memory_event(memcg
, MEMCG_OOM
);
1768 * We are in the middle of the charge context here, so we
1769 * don't want to block when potentially sitting on a callstack
1770 * that holds all kinds of filesystem and mm locks.
1772 * cgroup1 allows disabling the OOM killer and waiting for outside
1773 * handling until the charge can succeed; remember the context and put
1774 * the task to sleep at the end of the page fault when all locks are
1777 * On the other hand, in-kernel OOM killer allows for an async victim
1778 * memory reclaim (oom_reaper) and that means that we are not solely
1779 * relying on the oom victim to make a forward progress and we can
1780 * invoke the oom killer here.
1782 * Please note that mem_cgroup_out_of_memory might fail to find a
1783 * victim and then we have to bail out from the charge path.
1785 if (memcg
->oom_kill_disable
) {
1786 if (!current
->in_user_fault
)
1788 css_get(&memcg
->css
);
1789 current
->memcg_in_oom
= memcg
;
1790 current
->memcg_oom_gfp_mask
= mask
;
1791 current
->memcg_oom_order
= order
;
1796 mem_cgroup_mark_under_oom(memcg
);
1798 locked
= mem_cgroup_oom_trylock(memcg
);
1801 mem_cgroup_oom_notify(memcg
);
1803 mem_cgroup_unmark_under_oom(memcg
);
1804 if (mem_cgroup_out_of_memory(memcg
, mask
, order
))
1810 mem_cgroup_oom_unlock(memcg
);
1816 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1817 * @handle: actually kill/wait or just clean up the OOM state
1819 * This has to be called at the end of a page fault if the memcg OOM
1820 * handler was enabled.
1822 * Memcg supports userspace OOM handling where failed allocations must
1823 * sleep on a waitqueue until the userspace task resolves the
1824 * situation. Sleeping directly in the charge context with all kinds
1825 * of locks held is not a good idea, instead we remember an OOM state
1826 * in the task and mem_cgroup_oom_synchronize() has to be called at
1827 * the end of the page fault to complete the OOM handling.
1829 * Returns %true if an ongoing memcg OOM situation was detected and
1830 * completed, %false otherwise.
1832 bool mem_cgroup_oom_synchronize(bool handle
)
1834 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1835 struct oom_wait_info owait
;
1838 /* OOM is global, do not handle */
1845 owait
.memcg
= memcg
;
1846 owait
.wait
.flags
= 0;
1847 owait
.wait
.func
= memcg_oom_wake_function
;
1848 owait
.wait
.private = current
;
1849 INIT_LIST_HEAD(&owait
.wait
.entry
);
1851 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1852 mem_cgroup_mark_under_oom(memcg
);
1854 locked
= mem_cgroup_oom_trylock(memcg
);
1857 mem_cgroup_oom_notify(memcg
);
1859 if (locked
&& !memcg
->oom_kill_disable
) {
1860 mem_cgroup_unmark_under_oom(memcg
);
1861 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1862 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1863 current
->memcg_oom_order
);
1866 mem_cgroup_unmark_under_oom(memcg
);
1867 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1871 mem_cgroup_oom_unlock(memcg
);
1873 * There is no guarantee that an OOM-lock contender
1874 * sees the wakeups triggered by the OOM kill
1875 * uncharges. Wake any sleepers explicitely.
1877 memcg_oom_recover(memcg
);
1880 current
->memcg_in_oom
= NULL
;
1881 css_put(&memcg
->css
);
1886 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1887 * @victim: task to be killed by the OOM killer
1888 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1890 * Returns a pointer to a memory cgroup, which has to be cleaned up
1891 * by killing all belonging OOM-killable tasks.
1893 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1895 struct mem_cgroup
*mem_cgroup_get_oom_group(struct task_struct
*victim
,
1896 struct mem_cgroup
*oom_domain
)
1898 struct mem_cgroup
*oom_group
= NULL
;
1899 struct mem_cgroup
*memcg
;
1901 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1905 oom_domain
= root_mem_cgroup
;
1909 memcg
= mem_cgroup_from_task(victim
);
1910 if (memcg
== root_mem_cgroup
)
1914 * If the victim task has been asynchronously moved to a different
1915 * memory cgroup, we might end up killing tasks outside oom_domain.
1916 * In this case it's better to ignore memory.group.oom.
1918 if (unlikely(!mem_cgroup_is_descendant(memcg
, oom_domain
)))
1922 * Traverse the memory cgroup hierarchy from the victim task's
1923 * cgroup up to the OOMing cgroup (or root) to find the
1924 * highest-level memory cgroup with oom.group set.
1926 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
1927 if (memcg
->oom_group
)
1930 if (memcg
== oom_domain
)
1935 css_get(&oom_group
->css
);
1942 void mem_cgroup_print_oom_group(struct mem_cgroup
*memcg
)
1944 pr_info("Tasks in ");
1945 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1946 pr_cont(" are going to be killed due to memory.oom.group set\n");
1950 * lock_page_memcg - lock a page->mem_cgroup binding
1953 * This function protects unlocked LRU pages from being moved to
1956 * It ensures lifetime of the returned memcg. Caller is responsible
1957 * for the lifetime of the page; __unlock_page_memcg() is available
1958 * when @page might get freed inside the locked section.
1960 struct mem_cgroup
*lock_page_memcg(struct page
*page
)
1962 struct page
*head
= compound_head(page
); /* rmap on tail pages */
1963 struct mem_cgroup
*memcg
;
1964 unsigned long flags
;
1967 * The RCU lock is held throughout the transaction. The fast
1968 * path can get away without acquiring the memcg->move_lock
1969 * because page moving starts with an RCU grace period.
1971 * The RCU lock also protects the memcg from being freed when
1972 * the page state that is going to change is the only thing
1973 * preventing the page itself from being freed. E.g. writeback
1974 * doesn't hold a page reference and relies on PG_writeback to
1975 * keep off truncation, migration and so forth.
1979 if (mem_cgroup_disabled())
1982 memcg
= head
->mem_cgroup
;
1983 if (unlikely(!memcg
))
1986 if (atomic_read(&memcg
->moving_account
) <= 0)
1989 spin_lock_irqsave(&memcg
->move_lock
, flags
);
1990 if (memcg
!= head
->mem_cgroup
) {
1991 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
1996 * When charge migration first begins, we can have locked and
1997 * unlocked page stat updates happening concurrently. Track
1998 * the task who has the lock for unlock_page_memcg().
2000 memcg
->move_lock_task
= current
;
2001 memcg
->move_lock_flags
= flags
;
2005 EXPORT_SYMBOL(lock_page_memcg
);
2008 * __unlock_page_memcg - unlock and unpin a memcg
2011 * Unlock and unpin a memcg returned by lock_page_memcg().
2013 void __unlock_page_memcg(struct mem_cgroup
*memcg
)
2015 if (memcg
&& memcg
->move_lock_task
== current
) {
2016 unsigned long flags
= memcg
->move_lock_flags
;
2018 memcg
->move_lock_task
= NULL
;
2019 memcg
->move_lock_flags
= 0;
2021 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2028 * unlock_page_memcg - unlock a page->mem_cgroup binding
2031 void unlock_page_memcg(struct page
*page
)
2033 struct page
*head
= compound_head(page
);
2035 __unlock_page_memcg(head
->mem_cgroup
);
2037 EXPORT_SYMBOL(unlock_page_memcg
);
2039 struct memcg_stock_pcp
{
2040 struct mem_cgroup
*cached
; /* this never be root cgroup */
2041 unsigned int nr_pages
;
2042 struct work_struct work
;
2043 unsigned long flags
;
2044 #define FLUSHING_CACHED_CHARGE 0
2046 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2047 static DEFINE_MUTEX(percpu_charge_mutex
);
2050 * consume_stock: Try to consume stocked charge on this cpu.
2051 * @memcg: memcg to consume from.
2052 * @nr_pages: how many pages to charge.
2054 * The charges will only happen if @memcg matches the current cpu's memcg
2055 * stock, and at least @nr_pages are available in that stock. Failure to
2056 * service an allocation will refill the stock.
2058 * returns true if successful, false otherwise.
2060 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2062 struct memcg_stock_pcp
*stock
;
2063 unsigned long flags
;
2066 if (nr_pages
> MEMCG_CHARGE_BATCH
)
2069 local_irq_save(flags
);
2071 stock
= this_cpu_ptr(&memcg_stock
);
2072 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
2073 stock
->nr_pages
-= nr_pages
;
2077 local_irq_restore(flags
);
2083 * Returns stocks cached in percpu and reset cached information.
2085 static void drain_stock(struct memcg_stock_pcp
*stock
)
2087 struct mem_cgroup
*old
= stock
->cached
;
2089 if (stock
->nr_pages
) {
2090 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
2091 if (do_memsw_account())
2092 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
2093 css_put_many(&old
->css
, stock
->nr_pages
);
2094 stock
->nr_pages
= 0;
2096 stock
->cached
= NULL
;
2099 static void drain_local_stock(struct work_struct
*dummy
)
2101 struct memcg_stock_pcp
*stock
;
2102 unsigned long flags
;
2105 * The only protection from memory hotplug vs. drain_stock races is
2106 * that we always operate on local CPU stock here with IRQ disabled
2108 local_irq_save(flags
);
2110 stock
= this_cpu_ptr(&memcg_stock
);
2112 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2114 local_irq_restore(flags
);
2118 * Cache charges(val) to local per_cpu area.
2119 * This will be consumed by consume_stock() function, later.
2121 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2123 struct memcg_stock_pcp
*stock
;
2124 unsigned long flags
;
2126 local_irq_save(flags
);
2128 stock
= this_cpu_ptr(&memcg_stock
);
2129 if (stock
->cached
!= memcg
) { /* reset if necessary */
2131 stock
->cached
= memcg
;
2133 stock
->nr_pages
+= nr_pages
;
2135 if (stock
->nr_pages
> MEMCG_CHARGE_BATCH
)
2138 local_irq_restore(flags
);
2142 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2143 * of the hierarchy under it.
2145 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
2149 /* If someone's already draining, avoid adding running more workers. */
2150 if (!mutex_trylock(&percpu_charge_mutex
))
2153 * Notify other cpus that system-wide "drain" is running
2154 * We do not care about races with the cpu hotplug because cpu down
2155 * as well as workers from this path always operate on the local
2156 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2159 for_each_online_cpu(cpu
) {
2160 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2161 struct mem_cgroup
*memcg
;
2165 memcg
= stock
->cached
;
2166 if (memcg
&& stock
->nr_pages
&&
2167 mem_cgroup_is_descendant(memcg
, root_memcg
))
2172 !test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2174 drain_local_stock(&stock
->work
);
2176 schedule_work_on(cpu
, &stock
->work
);
2180 mutex_unlock(&percpu_charge_mutex
);
2183 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
2185 struct memcg_stock_pcp
*stock
;
2186 struct mem_cgroup
*memcg
, *mi
;
2188 stock
= &per_cpu(memcg_stock
, cpu
);
2191 for_each_mem_cgroup(memcg
) {
2194 for (i
= 0; i
< MEMCG_NR_STAT
; i
++) {
2198 x
= this_cpu_xchg(memcg
->vmstats_percpu
->stat
[i
], 0);
2200 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
2201 atomic_long_add(x
, &memcg
->vmstats
[i
]);
2203 if (i
>= NR_VM_NODE_STAT_ITEMS
)
2206 for_each_node(nid
) {
2207 struct mem_cgroup_per_node
*pn
;
2209 pn
= mem_cgroup_nodeinfo(memcg
, nid
);
2210 x
= this_cpu_xchg(pn
->lruvec_stat_cpu
->count
[i
], 0);
2213 atomic_long_add(x
, &pn
->lruvec_stat
[i
]);
2214 } while ((pn
= parent_nodeinfo(pn
, nid
)));
2218 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++) {
2221 x
= this_cpu_xchg(memcg
->vmstats_percpu
->events
[i
], 0);
2223 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
2224 atomic_long_add(x
, &memcg
->vmevents
[i
]);
2231 static void reclaim_high(struct mem_cgroup
*memcg
,
2232 unsigned int nr_pages
,
2236 if (page_counter_read(&memcg
->memory
) <=
2237 READ_ONCE(memcg
->memory
.high
))
2239 memcg_memory_event(memcg
, MEMCG_HIGH
);
2240 try_to_free_mem_cgroup_pages(memcg
, nr_pages
, gfp_mask
, true);
2241 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2242 !mem_cgroup_is_root(memcg
));
2245 static void high_work_func(struct work_struct
*work
)
2247 struct mem_cgroup
*memcg
;
2249 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
2250 reclaim_high(memcg
, MEMCG_CHARGE_BATCH
, GFP_KERNEL
);
2254 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2255 * enough to still cause a significant slowdown in most cases, while still
2256 * allowing diagnostics and tracing to proceed without becoming stuck.
2258 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2261 * When calculating the delay, we use these either side of the exponentiation to
2262 * maintain precision and scale to a reasonable number of jiffies (see the table
2265 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2266 * overage ratio to a delay.
2267 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down down the
2268 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2269 * to produce a reasonable delay curve.
2271 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2272 * reasonable delay curve compared to precision-adjusted overage, not
2273 * penalising heavily at first, but still making sure that growth beyond the
2274 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2275 * example, with a high of 100 megabytes:
2277 * +-------+------------------------+
2278 * | usage | time to allocate in ms |
2279 * +-------+------------------------+
2301 * +-------+------------------------+
2303 #define MEMCG_DELAY_PRECISION_SHIFT 20
2304 #define MEMCG_DELAY_SCALING_SHIFT 14
2306 static u64
calculate_overage(unsigned long usage
, unsigned long high
)
2314 * Prevent division by 0 in overage calculation by acting as if
2315 * it was a threshold of 1 page
2317 high
= max(high
, 1UL);
2319 overage
= usage
- high
;
2320 overage
<<= MEMCG_DELAY_PRECISION_SHIFT
;
2321 return div64_u64(overage
, high
);
2324 static u64
mem_find_max_overage(struct mem_cgroup
*memcg
)
2326 u64 overage
, max_overage
= 0;
2329 overage
= calculate_overage(page_counter_read(&memcg
->memory
),
2330 READ_ONCE(memcg
->memory
.high
));
2331 max_overage
= max(overage
, max_overage
);
2332 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2333 !mem_cgroup_is_root(memcg
));
2338 static u64
swap_find_max_overage(struct mem_cgroup
*memcg
)
2340 u64 overage
, max_overage
= 0;
2343 overage
= calculate_overage(page_counter_read(&memcg
->swap
),
2344 READ_ONCE(memcg
->swap
.high
));
2346 memcg_memory_event(memcg
, MEMCG_SWAP_HIGH
);
2347 max_overage
= max(overage
, max_overage
);
2348 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2349 !mem_cgroup_is_root(memcg
));
2355 * Get the number of jiffies that we should penalise a mischievous cgroup which
2356 * is exceeding its memory.high by checking both it and its ancestors.
2358 static unsigned long calculate_high_delay(struct mem_cgroup
*memcg
,
2359 unsigned int nr_pages
,
2362 unsigned long penalty_jiffies
;
2368 * We use overage compared to memory.high to calculate the number of
2369 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2370 * fairly lenient on small overages, and increasingly harsh when the
2371 * memcg in question makes it clear that it has no intention of stopping
2372 * its crazy behaviour, so we exponentially increase the delay based on
2375 penalty_jiffies
= max_overage
* max_overage
* HZ
;
2376 penalty_jiffies
>>= MEMCG_DELAY_PRECISION_SHIFT
;
2377 penalty_jiffies
>>= MEMCG_DELAY_SCALING_SHIFT
;
2380 * Factor in the task's own contribution to the overage, such that four
2381 * N-sized allocations are throttled approximately the same as one
2382 * 4N-sized allocation.
2384 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2385 * larger the current charge patch is than that.
2387 return penalty_jiffies
* nr_pages
/ MEMCG_CHARGE_BATCH
;
2391 * Scheduled by try_charge() to be executed from the userland return path
2392 * and reclaims memory over the high limit.
2394 void mem_cgroup_handle_over_high(void)
2396 unsigned long penalty_jiffies
;
2397 unsigned long pflags
;
2398 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
2399 struct mem_cgroup
*memcg
;
2401 if (likely(!nr_pages
))
2404 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2405 reclaim_high(memcg
, nr_pages
, GFP_KERNEL
);
2406 current
->memcg_nr_pages_over_high
= 0;
2409 * memory.high is breached and reclaim is unable to keep up. Throttle
2410 * allocators proactively to slow down excessive growth.
2412 penalty_jiffies
= calculate_high_delay(memcg
, nr_pages
,
2413 mem_find_max_overage(memcg
));
2415 penalty_jiffies
+= calculate_high_delay(memcg
, nr_pages
,
2416 swap_find_max_overage(memcg
));
2419 * Clamp the max delay per usermode return so as to still keep the
2420 * application moving forwards and also permit diagnostics, albeit
2423 penalty_jiffies
= min(penalty_jiffies
, MEMCG_MAX_HIGH_DELAY_JIFFIES
);
2426 * Don't sleep if the amount of jiffies this memcg owes us is so low
2427 * that it's not even worth doing, in an attempt to be nice to those who
2428 * go only a small amount over their memory.high value and maybe haven't
2429 * been aggressively reclaimed enough yet.
2431 if (penalty_jiffies
<= HZ
/ 100)
2435 * If we exit early, we're guaranteed to die (since
2436 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2437 * need to account for any ill-begotten jiffies to pay them off later.
2439 psi_memstall_enter(&pflags
);
2440 schedule_timeout_killable(penalty_jiffies
);
2441 psi_memstall_leave(&pflags
);
2444 css_put(&memcg
->css
);
2447 static int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2448 unsigned int nr_pages
)
2450 unsigned int batch
= max(MEMCG_CHARGE_BATCH
, nr_pages
);
2451 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2452 struct mem_cgroup
*mem_over_limit
;
2453 struct page_counter
*counter
;
2454 unsigned long nr_reclaimed
;
2455 bool may_swap
= true;
2456 bool drained
= false;
2457 enum oom_status oom_status
;
2459 if (mem_cgroup_is_root(memcg
))
2462 if (consume_stock(memcg
, nr_pages
))
2465 if (!do_memsw_account() ||
2466 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
2467 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
2469 if (do_memsw_account())
2470 page_counter_uncharge(&memcg
->memsw
, batch
);
2471 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
2473 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
2477 if (batch
> nr_pages
) {
2483 * Memcg doesn't have a dedicated reserve for atomic
2484 * allocations. But like the global atomic pool, we need to
2485 * put the burden of reclaim on regular allocation requests
2486 * and let these go through as privileged allocations.
2488 if (gfp_mask
& __GFP_ATOMIC
)
2492 * Unlike in global OOM situations, memcg is not in a physical
2493 * memory shortage. Allow dying and OOM-killed tasks to
2494 * bypass the last charges so that they can exit quickly and
2495 * free their memory.
2497 if (unlikely(should_force_charge()))
2501 * Prevent unbounded recursion when reclaim operations need to
2502 * allocate memory. This might exceed the limits temporarily,
2503 * but we prefer facilitating memory reclaim and getting back
2504 * under the limit over triggering OOM kills in these cases.
2506 if (unlikely(current
->flags
& PF_MEMALLOC
))
2509 if (unlikely(task_in_memcg_oom(current
)))
2512 if (!gfpflags_allow_blocking(gfp_mask
))
2515 memcg_memory_event(mem_over_limit
, MEMCG_MAX
);
2517 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
2518 gfp_mask
, may_swap
);
2520 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2524 drain_all_stock(mem_over_limit
);
2529 if (gfp_mask
& __GFP_NORETRY
)
2532 * Even though the limit is exceeded at this point, reclaim
2533 * may have been able to free some pages. Retry the charge
2534 * before killing the task.
2536 * Only for regular pages, though: huge pages are rather
2537 * unlikely to succeed so close to the limit, and we fall back
2538 * to regular pages anyway in case of failure.
2540 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
2543 * At task move, charge accounts can be doubly counted. So, it's
2544 * better to wait until the end of task_move if something is going on.
2546 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2552 if (gfp_mask
& __GFP_RETRY_MAYFAIL
)
2555 if (gfp_mask
& __GFP_NOFAIL
)
2558 if (fatal_signal_pending(current
))
2562 * keep retrying as long as the memcg oom killer is able to make
2563 * a forward progress or bypass the charge if the oom killer
2564 * couldn't make any progress.
2566 oom_status
= mem_cgroup_oom(mem_over_limit
, gfp_mask
,
2567 get_order(nr_pages
* PAGE_SIZE
));
2568 switch (oom_status
) {
2570 nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
2578 if (!(gfp_mask
& __GFP_NOFAIL
))
2582 * The allocation either can't fail or will lead to more memory
2583 * being freed very soon. Allow memory usage go over the limit
2584 * temporarily by force charging it.
2586 page_counter_charge(&memcg
->memory
, nr_pages
);
2587 if (do_memsw_account())
2588 page_counter_charge(&memcg
->memsw
, nr_pages
);
2589 css_get_many(&memcg
->css
, nr_pages
);
2594 css_get_many(&memcg
->css
, batch
);
2595 if (batch
> nr_pages
)
2596 refill_stock(memcg
, batch
- nr_pages
);
2599 * If the hierarchy is above the normal consumption range, schedule
2600 * reclaim on returning to userland. We can perform reclaim here
2601 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2602 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2603 * not recorded as it most likely matches current's and won't
2604 * change in the meantime. As high limit is checked again before
2605 * reclaim, the cost of mismatch is negligible.
2608 bool mem_high
, swap_high
;
2610 mem_high
= page_counter_read(&memcg
->memory
) >
2611 READ_ONCE(memcg
->memory
.high
);
2612 swap_high
= page_counter_read(&memcg
->swap
) >
2613 READ_ONCE(memcg
->swap
.high
);
2615 /* Don't bother a random interrupted task */
2616 if (in_interrupt()) {
2618 schedule_work(&memcg
->high_work
);
2624 if (mem_high
|| swap_high
) {
2626 * The allocating tasks in this cgroup will need to do
2627 * reclaim or be throttled to prevent further growth
2628 * of the memory or swap footprints.
2630 * Target some best-effort fairness between the tasks,
2631 * and distribute reclaim work and delay penalties
2632 * based on how much each task is actually allocating.
2634 current
->memcg_nr_pages_over_high
+= batch
;
2635 set_notify_resume(current
);
2638 } while ((memcg
= parent_mem_cgroup(memcg
)));
2643 #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
2644 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2646 if (mem_cgroup_is_root(memcg
))
2649 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2650 if (do_memsw_account())
2651 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2653 css_put_many(&memcg
->css
, nr_pages
);
2657 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
)
2659 VM_BUG_ON_PAGE(page
->mem_cgroup
, page
);
2661 * Any of the following ensures page->mem_cgroup stability:
2665 * - lock_page_memcg()
2666 * - exclusive reference
2668 page
->mem_cgroup
= memcg
;
2671 #ifdef CONFIG_MEMCG_KMEM
2673 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2675 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2676 * cgroup_mutex, etc.
2678 struct mem_cgroup
*mem_cgroup_from_obj(void *p
)
2682 if (mem_cgroup_disabled())
2685 page
= virt_to_head_page(p
);
2688 * Slab pages don't have page->mem_cgroup set because corresponding
2689 * kmem caches can be reparented during the lifetime. That's why
2690 * memcg_from_slab_page() should be used instead.
2693 return memcg_from_slab_page(page
);
2695 /* All other pages use page->mem_cgroup */
2696 return page
->mem_cgroup
;
2699 static int memcg_alloc_cache_id(void)
2704 id
= ida_simple_get(&memcg_cache_ida
,
2705 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2709 if (id
< memcg_nr_cache_ids
)
2713 * There's no space for the new id in memcg_caches arrays,
2714 * so we have to grow them.
2716 down_write(&memcg_cache_ids_sem
);
2718 size
= 2 * (id
+ 1);
2719 if (size
< MEMCG_CACHES_MIN_SIZE
)
2720 size
= MEMCG_CACHES_MIN_SIZE
;
2721 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2722 size
= MEMCG_CACHES_MAX_SIZE
;
2724 err
= memcg_update_all_caches(size
);
2726 err
= memcg_update_all_list_lrus(size
);
2728 memcg_nr_cache_ids
= size
;
2730 up_write(&memcg_cache_ids_sem
);
2733 ida_simple_remove(&memcg_cache_ida
, id
);
2739 static void memcg_free_cache_id(int id
)
2741 ida_simple_remove(&memcg_cache_ida
, id
);
2744 struct memcg_kmem_cache_create_work
{
2745 struct mem_cgroup
*memcg
;
2746 struct kmem_cache
*cachep
;
2747 struct work_struct work
;
2750 static void memcg_kmem_cache_create_func(struct work_struct
*w
)
2752 struct memcg_kmem_cache_create_work
*cw
=
2753 container_of(w
, struct memcg_kmem_cache_create_work
, work
);
2754 struct mem_cgroup
*memcg
= cw
->memcg
;
2755 struct kmem_cache
*cachep
= cw
->cachep
;
2757 memcg_create_kmem_cache(memcg
, cachep
);
2759 css_put(&memcg
->css
);
2764 * Enqueue the creation of a per-memcg kmem_cache.
2766 static void memcg_schedule_kmem_cache_create(struct mem_cgroup
*memcg
,
2767 struct kmem_cache
*cachep
)
2769 struct memcg_kmem_cache_create_work
*cw
;
2771 if (!css_tryget_online(&memcg
->css
))
2774 cw
= kmalloc(sizeof(*cw
), GFP_NOWAIT
| __GFP_NOWARN
);
2779 cw
->cachep
= cachep
;
2780 INIT_WORK(&cw
->work
, memcg_kmem_cache_create_func
);
2782 queue_work(memcg_kmem_cache_wq
, &cw
->work
);
2785 static inline bool memcg_kmem_bypass(void)
2790 /* Allow remote memcg charging in kthread contexts. */
2791 if ((!current
->mm
|| (current
->flags
& PF_KTHREAD
)) &&
2792 !current
->active_memcg
)
2798 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2799 * @cachep: the original global kmem cache
2801 * Return the kmem_cache we're supposed to use for a slab allocation.
2802 * We try to use the current memcg's version of the cache.
2804 * If the cache does not exist yet, if we are the first user of it, we
2805 * create it asynchronously in a workqueue and let the current allocation
2806 * go through with the original cache.
2808 * This function takes a reference to the cache it returns to assure it
2809 * won't get destroyed while we are working with it. Once the caller is
2810 * done with it, memcg_kmem_put_cache() must be called to release the
2813 struct kmem_cache
*memcg_kmem_get_cache(struct kmem_cache
*cachep
)
2815 struct mem_cgroup
*memcg
;
2816 struct kmem_cache
*memcg_cachep
;
2817 struct memcg_cache_array
*arr
;
2820 VM_BUG_ON(!is_root_cache(cachep
));
2822 if (memcg_kmem_bypass())
2827 if (unlikely(current
->active_memcg
))
2828 memcg
= current
->active_memcg
;
2830 memcg
= mem_cgroup_from_task(current
);
2832 if (!memcg
|| memcg
== root_mem_cgroup
)
2835 kmemcg_id
= READ_ONCE(memcg
->kmemcg_id
);
2839 arr
= rcu_dereference(cachep
->memcg_params
.memcg_caches
);
2842 * Make sure we will access the up-to-date value. The code updating
2843 * memcg_caches issues a write barrier to match the data dependency
2844 * barrier inside READ_ONCE() (see memcg_create_kmem_cache()).
2846 memcg_cachep
= READ_ONCE(arr
->entries
[kmemcg_id
]);
2849 * If we are in a safe context (can wait, and not in interrupt
2850 * context), we could be be predictable and return right away.
2851 * This would guarantee that the allocation being performed
2852 * already belongs in the new cache.
2854 * However, there are some clashes that can arrive from locking.
2855 * For instance, because we acquire the slab_mutex while doing
2856 * memcg_create_kmem_cache, this means no further allocation
2857 * could happen with the slab_mutex held. So it's better to
2860 * If the memcg is dying or memcg_cache is about to be released,
2861 * don't bother creating new kmem_caches. Because memcg_cachep
2862 * is ZEROed as the fist step of kmem offlining, we don't need
2863 * percpu_ref_tryget_live() here. css_tryget_online() check in
2864 * memcg_schedule_kmem_cache_create() will prevent us from
2865 * creation of a new kmem_cache.
2867 if (unlikely(!memcg_cachep
))
2868 memcg_schedule_kmem_cache_create(memcg
, cachep
);
2869 else if (percpu_ref_tryget(&memcg_cachep
->memcg_params
.refcnt
))
2870 cachep
= memcg_cachep
;
2877 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2878 * @cachep: the cache returned by memcg_kmem_get_cache
2880 void memcg_kmem_put_cache(struct kmem_cache
*cachep
)
2882 if (!is_root_cache(cachep
))
2883 percpu_ref_put(&cachep
->memcg_params
.refcnt
);
2887 * __memcg_kmem_charge: charge a number of kernel pages to a memcg
2888 * @memcg: memory cgroup to charge
2889 * @gfp: reclaim mode
2890 * @nr_pages: number of pages to charge
2892 * Returns 0 on success, an error code on failure.
2894 int __memcg_kmem_charge(struct mem_cgroup
*memcg
, gfp_t gfp
,
2895 unsigned int nr_pages
)
2897 struct page_counter
*counter
;
2900 ret
= try_charge(memcg
, gfp
, nr_pages
);
2904 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2905 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2908 * Enforce __GFP_NOFAIL allocation because callers are not
2909 * prepared to see failures and likely do not have any failure
2912 if (gfp
& __GFP_NOFAIL
) {
2913 page_counter_charge(&memcg
->kmem
, nr_pages
);
2916 cancel_charge(memcg
, nr_pages
);
2923 * __memcg_kmem_uncharge: uncharge a number of kernel pages from a memcg
2924 * @memcg: memcg to uncharge
2925 * @nr_pages: number of pages to uncharge
2927 void __memcg_kmem_uncharge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2929 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2930 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2932 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2933 if (do_memsw_account())
2934 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2938 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
2939 * @page: page to charge
2940 * @gfp: reclaim mode
2941 * @order: allocation order
2943 * Returns 0 on success, an error code on failure.
2945 int __memcg_kmem_charge_page(struct page
*page
, gfp_t gfp
, int order
)
2947 struct mem_cgroup
*memcg
;
2950 if (memcg_kmem_bypass())
2953 memcg
= get_mem_cgroup_from_current();
2954 if (!mem_cgroup_is_root(memcg
)) {
2955 ret
= __memcg_kmem_charge(memcg
, gfp
, 1 << order
);
2957 page
->mem_cgroup
= memcg
;
2958 __SetPageKmemcg(page
);
2961 css_put(&memcg
->css
);
2966 * __memcg_kmem_uncharge_page: uncharge a kmem page
2967 * @page: page to uncharge
2968 * @order: allocation order
2970 void __memcg_kmem_uncharge_page(struct page
*page
, int order
)
2972 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
2973 unsigned int nr_pages
= 1 << order
;
2978 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg
), page
);
2979 __memcg_kmem_uncharge(memcg
, nr_pages
);
2980 page
->mem_cgroup
= NULL
;
2982 /* slab pages do not have PageKmemcg flag set */
2983 if (PageKmemcg(page
))
2984 __ClearPageKmemcg(page
);
2986 css_put_many(&memcg
->css
, nr_pages
);
2988 #endif /* CONFIG_MEMCG_KMEM */
2990 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2993 * Because tail pages are not marked as "used", set it. We're under
2994 * pgdat->lru_lock and migration entries setup in all page mappings.
2996 void mem_cgroup_split_huge_fixup(struct page
*head
)
3000 if (mem_cgroup_disabled())
3003 for (i
= 1; i
< HPAGE_PMD_NR
; i
++)
3004 head
[i
].mem_cgroup
= head
->mem_cgroup
;
3006 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3008 #ifdef CONFIG_MEMCG_SWAP
3010 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3011 * @entry: swap entry to be moved
3012 * @from: mem_cgroup which the entry is moved from
3013 * @to: mem_cgroup which the entry is moved to
3015 * It succeeds only when the swap_cgroup's record for this entry is the same
3016 * as the mem_cgroup's id of @from.
3018 * Returns 0 on success, -EINVAL on failure.
3020 * The caller must have charged to @to, IOW, called page_counter_charge() about
3021 * both res and memsw, and called css_get().
3023 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3024 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3026 unsigned short old_id
, new_id
;
3028 old_id
= mem_cgroup_id(from
);
3029 new_id
= mem_cgroup_id(to
);
3031 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3032 mod_memcg_state(from
, MEMCG_SWAP
, -1);
3033 mod_memcg_state(to
, MEMCG_SWAP
, 1);
3039 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3040 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3046 static DEFINE_MUTEX(memcg_max_mutex
);
3048 static int mem_cgroup_resize_max(struct mem_cgroup
*memcg
,
3049 unsigned long max
, bool memsw
)
3051 bool enlarge
= false;
3052 bool drained
= false;
3054 bool limits_invariant
;
3055 struct page_counter
*counter
= memsw
? &memcg
->memsw
: &memcg
->memory
;
3058 if (signal_pending(current
)) {
3063 mutex_lock(&memcg_max_mutex
);
3065 * Make sure that the new limit (memsw or memory limit) doesn't
3066 * break our basic invariant rule memory.max <= memsw.max.
3068 limits_invariant
= memsw
? max
>= READ_ONCE(memcg
->memory
.max
) :
3069 max
<= memcg
->memsw
.max
;
3070 if (!limits_invariant
) {
3071 mutex_unlock(&memcg_max_mutex
);
3075 if (max
> counter
->max
)
3077 ret
= page_counter_set_max(counter
, max
);
3078 mutex_unlock(&memcg_max_mutex
);
3084 drain_all_stock(memcg
);
3089 if (!try_to_free_mem_cgroup_pages(memcg
, 1,
3090 GFP_KERNEL
, !memsw
)) {
3096 if (!ret
&& enlarge
)
3097 memcg_oom_recover(memcg
);
3102 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
3104 unsigned long *total_scanned
)
3106 unsigned long nr_reclaimed
= 0;
3107 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
3108 unsigned long reclaimed
;
3110 struct mem_cgroup_tree_per_node
*mctz
;
3111 unsigned long excess
;
3112 unsigned long nr_scanned
;
3117 mctz
= soft_limit_tree_node(pgdat
->node_id
);
3120 * Do not even bother to check the largest node if the root
3121 * is empty. Do it lockless to prevent lock bouncing. Races
3122 * are acceptable as soft limit is best effort anyway.
3124 if (!mctz
|| RB_EMPTY_ROOT(&mctz
->rb_root
))
3128 * This loop can run a while, specially if mem_cgroup's continuously
3129 * keep exceeding their soft limit and putting the system under
3136 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3141 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
3142 gfp_mask
, &nr_scanned
);
3143 nr_reclaimed
+= reclaimed
;
3144 *total_scanned
+= nr_scanned
;
3145 spin_lock_irq(&mctz
->lock
);
3146 __mem_cgroup_remove_exceeded(mz
, mctz
);
3149 * If we failed to reclaim anything from this memory cgroup
3150 * it is time to move on to the next cgroup
3154 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
3156 excess
= soft_limit_excess(mz
->memcg
);
3158 * One school of thought says that we should not add
3159 * back the node to the tree if reclaim returns 0.
3160 * But our reclaim could return 0, simply because due
3161 * to priority we are exposing a smaller subset of
3162 * memory to reclaim from. Consider this as a longer
3165 /* If excess == 0, no tree ops */
3166 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
3167 spin_unlock_irq(&mctz
->lock
);
3168 css_put(&mz
->memcg
->css
);
3171 * Could not reclaim anything and there are no more
3172 * mem cgroups to try or we seem to be looping without
3173 * reclaiming anything.
3175 if (!nr_reclaimed
&&
3177 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3179 } while (!nr_reclaimed
);
3181 css_put(&next_mz
->memcg
->css
);
3182 return nr_reclaimed
;
3186 * Test whether @memcg has children, dead or alive. Note that this
3187 * function doesn't care whether @memcg has use_hierarchy enabled and
3188 * returns %true if there are child csses according to the cgroup
3189 * hierarchy. Testing use_hierarchy is the caller's responsibility.
3191 static inline bool memcg_has_children(struct mem_cgroup
*memcg
)
3196 ret
= css_next_child(NULL
, &memcg
->css
);
3202 * Reclaims as many pages from the given memcg as possible.
3204 * Caller is responsible for holding css reference for memcg.
3206 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3208 int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
3210 /* we call try-to-free pages for make this cgroup empty */
3211 lru_add_drain_all();
3213 drain_all_stock(memcg
);
3215 /* try to free all pages in this cgroup */
3216 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
3219 if (signal_pending(current
))
3222 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
3226 /* maybe some writeback is necessary */
3227 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3235 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
3236 char *buf
, size_t nbytes
,
3239 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3241 if (mem_cgroup_is_root(memcg
))
3243 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
3246 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
3249 return mem_cgroup_from_css(css
)->use_hierarchy
;
3252 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
3253 struct cftype
*cft
, u64 val
)
3256 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3257 struct mem_cgroup
*parent_memcg
= mem_cgroup_from_css(memcg
->css
.parent
);
3259 if (memcg
->use_hierarchy
== val
)
3263 * If parent's use_hierarchy is set, we can't make any modifications
3264 * in the child subtrees. If it is unset, then the change can
3265 * occur, provided the current cgroup has no children.
3267 * For the root cgroup, parent_mem is NULL, we allow value to be
3268 * set if there are no children.
3270 if ((!parent_memcg
|| !parent_memcg
->use_hierarchy
) &&
3271 (val
== 1 || val
== 0)) {
3272 if (!memcg_has_children(memcg
))
3273 memcg
->use_hierarchy
= val
;
3282 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3286 if (mem_cgroup_is_root(memcg
)) {
3287 val
= memcg_page_state(memcg
, NR_FILE_PAGES
) +
3288 memcg_page_state(memcg
, NR_ANON_MAPPED
);
3290 val
+= memcg_page_state(memcg
, MEMCG_SWAP
);
3293 val
= page_counter_read(&memcg
->memory
);
3295 val
= page_counter_read(&memcg
->memsw
);
3308 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
3311 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3312 struct page_counter
*counter
;
3314 switch (MEMFILE_TYPE(cft
->private)) {
3316 counter
= &memcg
->memory
;
3319 counter
= &memcg
->memsw
;
3322 counter
= &memcg
->kmem
;
3325 counter
= &memcg
->tcpmem
;
3331 switch (MEMFILE_ATTR(cft
->private)) {
3333 if (counter
== &memcg
->memory
)
3334 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
3335 if (counter
== &memcg
->memsw
)
3336 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
3337 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
3339 return (u64
)counter
->max
* PAGE_SIZE
;
3341 return (u64
)counter
->watermark
* PAGE_SIZE
;
3343 return counter
->failcnt
;
3344 case RES_SOFT_LIMIT
:
3345 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
3351 static void memcg_flush_percpu_vmstats(struct mem_cgroup
*memcg
)
3353 unsigned long stat
[MEMCG_NR_STAT
] = {0};
3354 struct mem_cgroup
*mi
;
3357 for_each_online_cpu(cpu
)
3358 for (i
= 0; i
< MEMCG_NR_STAT
; i
++)
3359 stat
[i
] += per_cpu(memcg
->vmstats_percpu
->stat
[i
], cpu
);
3361 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
3362 for (i
= 0; i
< MEMCG_NR_STAT
; i
++)
3363 atomic_long_add(stat
[i
], &mi
->vmstats
[i
]);
3365 for_each_node(node
) {
3366 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
3367 struct mem_cgroup_per_node
*pi
;
3369 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++)
3372 for_each_online_cpu(cpu
)
3373 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++)
3375 pn
->lruvec_stat_cpu
->count
[i
], cpu
);
3377 for (pi
= pn
; pi
; pi
= parent_nodeinfo(pi
, node
))
3378 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++)
3379 atomic_long_add(stat
[i
], &pi
->lruvec_stat
[i
]);
3383 static void memcg_flush_percpu_vmevents(struct mem_cgroup
*memcg
)
3385 unsigned long events
[NR_VM_EVENT_ITEMS
];
3386 struct mem_cgroup
*mi
;
3389 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3392 for_each_online_cpu(cpu
)
3393 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3394 events
[i
] += per_cpu(memcg
->vmstats_percpu
->events
[i
],
3397 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
))
3398 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++)
3399 atomic_long_add(events
[i
], &mi
->vmevents
[i
]);
3402 #ifdef CONFIG_MEMCG_KMEM
3403 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3407 if (cgroup_memory_nokmem
)
3410 BUG_ON(memcg
->kmemcg_id
>= 0);
3411 BUG_ON(memcg
->kmem_state
);
3413 memcg_id
= memcg_alloc_cache_id();
3417 static_branch_inc(&memcg_kmem_enabled_key
);
3419 * A memory cgroup is considered kmem-online as soon as it gets
3420 * kmemcg_id. Setting the id after enabling static branching will
3421 * guarantee no one starts accounting before all call sites are
3424 memcg
->kmemcg_id
= memcg_id
;
3425 memcg
->kmem_state
= KMEM_ONLINE
;
3426 INIT_LIST_HEAD(&memcg
->kmem_caches
);
3431 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3433 struct cgroup_subsys_state
*css
;
3434 struct mem_cgroup
*parent
, *child
;
3437 if (memcg
->kmem_state
!= KMEM_ONLINE
)
3440 * Clear the online state before clearing memcg_caches array
3441 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
3442 * guarantees that no cache will be created for this cgroup
3443 * after we are done (see memcg_create_kmem_cache()).
3445 memcg
->kmem_state
= KMEM_ALLOCATED
;
3447 parent
= parent_mem_cgroup(memcg
);
3449 parent
= root_mem_cgroup
;
3452 * Deactivate and reparent kmem_caches.
3454 memcg_deactivate_kmem_caches(memcg
, parent
);
3456 kmemcg_id
= memcg
->kmemcg_id
;
3457 BUG_ON(kmemcg_id
< 0);
3460 * Change kmemcg_id of this cgroup and all its descendants to the
3461 * parent's id, and then move all entries from this cgroup's list_lrus
3462 * to ones of the parent. After we have finished, all list_lrus
3463 * corresponding to this cgroup are guaranteed to remain empty. The
3464 * ordering is imposed by list_lru_node->lock taken by
3465 * memcg_drain_all_list_lrus().
3467 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3468 css_for_each_descendant_pre(css
, &memcg
->css
) {
3469 child
= mem_cgroup_from_css(css
);
3470 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
3471 child
->kmemcg_id
= parent
->kmemcg_id
;
3472 if (!memcg
->use_hierarchy
)
3477 memcg_drain_all_list_lrus(kmemcg_id
, parent
);
3479 memcg_free_cache_id(kmemcg_id
);
3482 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3484 /* css_alloc() failed, offlining didn't happen */
3485 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
3486 memcg_offline_kmem(memcg
);
3488 if (memcg
->kmem_state
== KMEM_ALLOCATED
) {
3489 WARN_ON(!list_empty(&memcg
->kmem_caches
));
3490 static_branch_dec(&memcg_kmem_enabled_key
);
3494 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3498 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3501 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3504 #endif /* CONFIG_MEMCG_KMEM */
3506 static int memcg_update_kmem_max(struct mem_cgroup
*memcg
,
3511 mutex_lock(&memcg_max_mutex
);
3512 ret
= page_counter_set_max(&memcg
->kmem
, max
);
3513 mutex_unlock(&memcg_max_mutex
);
3517 static int memcg_update_tcp_max(struct mem_cgroup
*memcg
, unsigned long max
)
3521 mutex_lock(&memcg_max_mutex
);
3523 ret
= page_counter_set_max(&memcg
->tcpmem
, max
);
3527 if (!memcg
->tcpmem_active
) {
3529 * The active flag needs to be written after the static_key
3530 * update. This is what guarantees that the socket activation
3531 * function is the last one to run. See mem_cgroup_sk_alloc()
3532 * for details, and note that we don't mark any socket as
3533 * belonging to this memcg until that flag is up.
3535 * We need to do this, because static_keys will span multiple
3536 * sites, but we can't control their order. If we mark a socket
3537 * as accounted, but the accounting functions are not patched in
3538 * yet, we'll lose accounting.
3540 * We never race with the readers in mem_cgroup_sk_alloc(),
3541 * because when this value change, the code to process it is not
3544 static_branch_inc(&memcg_sockets_enabled_key
);
3545 memcg
->tcpmem_active
= true;
3548 mutex_unlock(&memcg_max_mutex
);
3553 * The user of this function is...
3556 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
3557 char *buf
, size_t nbytes
, loff_t off
)
3559 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3560 unsigned long nr_pages
;
3563 buf
= strstrip(buf
);
3564 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
3568 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3570 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3574 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3576 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, false);
3579 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, true);
3582 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3583 "Please report your usecase to linux-mm@kvack.org if you "
3584 "depend on this functionality.\n");
3585 ret
= memcg_update_kmem_max(memcg
, nr_pages
);
3588 ret
= memcg_update_tcp_max(memcg
, nr_pages
);
3592 case RES_SOFT_LIMIT
:
3593 memcg
->soft_limit
= nr_pages
;
3597 return ret
?: nbytes
;
3600 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3601 size_t nbytes
, loff_t off
)
3603 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3604 struct page_counter
*counter
;
3606 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3608 counter
= &memcg
->memory
;
3611 counter
= &memcg
->memsw
;
3614 counter
= &memcg
->kmem
;
3617 counter
= &memcg
->tcpmem
;
3623 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3625 page_counter_reset_watermark(counter
);
3628 counter
->failcnt
= 0;
3637 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3640 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3644 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3645 struct cftype
*cft
, u64 val
)
3647 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3649 if (val
& ~MOVE_MASK
)
3653 * No kind of locking is needed in here, because ->can_attach() will
3654 * check this value once in the beginning of the process, and then carry
3655 * on with stale data. This means that changes to this value will only
3656 * affect task migrations starting after the change.
3658 memcg
->move_charge_at_immigrate
= val
;
3662 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3663 struct cftype
*cft
, u64 val
)
3671 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3672 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3673 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3675 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
3676 int nid
, unsigned int lru_mask
, bool tree
)
3678 struct lruvec
*lruvec
= mem_cgroup_lruvec(memcg
, NODE_DATA(nid
));
3679 unsigned long nr
= 0;
3682 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
3685 if (!(BIT(lru
) & lru_mask
))
3688 nr
+= lruvec_page_state(lruvec
, NR_LRU_BASE
+ lru
);
3690 nr
+= lruvec_page_state_local(lruvec
, NR_LRU_BASE
+ lru
);
3695 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
3696 unsigned int lru_mask
,
3699 unsigned long nr
= 0;
3703 if (!(BIT(lru
) & lru_mask
))
3706 nr
+= memcg_page_state(memcg
, NR_LRU_BASE
+ lru
);
3708 nr
+= memcg_page_state_local(memcg
, NR_LRU_BASE
+ lru
);
3713 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3717 unsigned int lru_mask
;
3720 static const struct numa_stat stats
[] = {
3721 { "total", LRU_ALL
},
3722 { "file", LRU_ALL_FILE
},
3723 { "anon", LRU_ALL_ANON
},
3724 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3726 const struct numa_stat
*stat
;
3728 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3730 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3731 seq_printf(m
, "%s=%lu", stat
->name
,
3732 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3734 for_each_node_state(nid
, N_MEMORY
)
3735 seq_printf(m
, " N%d=%lu", nid
,
3736 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3737 stat
->lru_mask
, false));
3741 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3743 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
,
3744 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3746 for_each_node_state(nid
, N_MEMORY
)
3747 seq_printf(m
, " N%d=%lu", nid
,
3748 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3749 stat
->lru_mask
, true));
3755 #endif /* CONFIG_NUMA */
3757 static const unsigned int memcg1_stats
[] = {
3760 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3770 static const char *const memcg1_stat_names
[] = {
3773 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3783 /* Universal VM events cgroup1 shows, original sort order */
3784 static const unsigned int memcg1_events
[] = {
3791 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3793 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3794 unsigned long memory
, memsw
;
3795 struct mem_cgroup
*mi
;
3798 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names
) != ARRAY_SIZE(memcg1_stats
));
3800 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3803 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3805 nr
= memcg_page_state_local(memcg
, memcg1_stats
[i
]);
3806 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3807 if (memcg1_stats
[i
] == NR_ANON_THPS
)
3810 seq_printf(m
, "%s %lu\n", memcg1_stat_names
[i
], nr
* PAGE_SIZE
);
3813 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3814 seq_printf(m
, "%s %lu\n", vm_event_name(memcg1_events
[i
]),
3815 memcg_events_local(memcg
, memcg1_events
[i
]));
3817 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3818 seq_printf(m
, "%s %lu\n", lru_list_name(i
),
3819 memcg_page_state_local(memcg
, NR_LRU_BASE
+ i
) *
3822 /* Hierarchical information */
3823 memory
= memsw
= PAGE_COUNTER_MAX
;
3824 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
3825 memory
= min(memory
, READ_ONCE(mi
->memory
.max
));
3826 memsw
= min(memsw
, READ_ONCE(mi
->memsw
.max
));
3828 seq_printf(m
, "hierarchical_memory_limit %llu\n",
3829 (u64
)memory
* PAGE_SIZE
);
3830 if (do_memsw_account())
3831 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
3832 (u64
)memsw
* PAGE_SIZE
);
3834 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3835 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3837 seq_printf(m
, "total_%s %llu\n", memcg1_stat_names
[i
],
3838 (u64
)memcg_page_state(memcg
, memcg1_stats
[i
]) *
3842 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3843 seq_printf(m
, "total_%s %llu\n",
3844 vm_event_name(memcg1_events
[i
]),
3845 (u64
)memcg_events(memcg
, memcg1_events
[i
]));
3847 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3848 seq_printf(m
, "total_%s %llu\n", lru_list_name(i
),
3849 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
3852 #ifdef CONFIG_DEBUG_VM
3855 struct mem_cgroup_per_node
*mz
;
3856 unsigned long anon_cost
= 0;
3857 unsigned long file_cost
= 0;
3859 for_each_online_pgdat(pgdat
) {
3860 mz
= mem_cgroup_nodeinfo(memcg
, pgdat
->node_id
);
3862 anon_cost
+= mz
->lruvec
.anon_cost
;
3863 file_cost
+= mz
->lruvec
.file_cost
;
3865 seq_printf(m
, "anon_cost %lu\n", anon_cost
);
3866 seq_printf(m
, "file_cost %lu\n", file_cost
);
3873 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
3876 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3878 return mem_cgroup_swappiness(memcg
);
3881 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
3882 struct cftype
*cft
, u64 val
)
3884 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3890 memcg
->swappiness
= val
;
3892 vm_swappiness
= val
;
3897 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
3899 struct mem_cgroup_threshold_ary
*t
;
3900 unsigned long usage
;
3905 t
= rcu_dereference(memcg
->thresholds
.primary
);
3907 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
3912 usage
= mem_cgroup_usage(memcg
, swap
);
3915 * current_threshold points to threshold just below or equal to usage.
3916 * If it's not true, a threshold was crossed after last
3917 * call of __mem_cgroup_threshold().
3919 i
= t
->current_threshold
;
3922 * Iterate backward over array of thresholds starting from
3923 * current_threshold and check if a threshold is crossed.
3924 * If none of thresholds below usage is crossed, we read
3925 * only one element of the array here.
3927 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
3928 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3930 /* i = current_threshold + 1 */
3934 * Iterate forward over array of thresholds starting from
3935 * current_threshold+1 and check if a threshold is crossed.
3936 * If none of thresholds above usage is crossed, we read
3937 * only one element of the array here.
3939 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
3940 eventfd_signal(t
->entries
[i
].eventfd
, 1);
3942 /* Update current_threshold */
3943 t
->current_threshold
= i
- 1;
3948 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
3951 __mem_cgroup_threshold(memcg
, false);
3952 if (do_memsw_account())
3953 __mem_cgroup_threshold(memcg
, true);
3955 memcg
= parent_mem_cgroup(memcg
);
3959 static int compare_thresholds(const void *a
, const void *b
)
3961 const struct mem_cgroup_threshold
*_a
= a
;
3962 const struct mem_cgroup_threshold
*_b
= b
;
3964 if (_a
->threshold
> _b
->threshold
)
3967 if (_a
->threshold
< _b
->threshold
)
3973 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
3975 struct mem_cgroup_eventfd_list
*ev
;
3977 spin_lock(&memcg_oom_lock
);
3979 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
3980 eventfd_signal(ev
->eventfd
, 1);
3982 spin_unlock(&memcg_oom_lock
);
3986 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
3988 struct mem_cgroup
*iter
;
3990 for_each_mem_cgroup_tree(iter
, memcg
)
3991 mem_cgroup_oom_notify_cb(iter
);
3994 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
3995 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
3997 struct mem_cgroup_thresholds
*thresholds
;
3998 struct mem_cgroup_threshold_ary
*new;
3999 unsigned long threshold
;
4000 unsigned long usage
;
4003 ret
= page_counter_memparse(args
, "-1", &threshold
);
4007 mutex_lock(&memcg
->thresholds_lock
);
4010 thresholds
= &memcg
->thresholds
;
4011 usage
= mem_cgroup_usage(memcg
, false);
4012 } else if (type
== _MEMSWAP
) {
4013 thresholds
= &memcg
->memsw_thresholds
;
4014 usage
= mem_cgroup_usage(memcg
, true);
4018 /* Check if a threshold crossed before adding a new one */
4019 if (thresholds
->primary
)
4020 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4022 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4024 /* Allocate memory for new array of thresholds */
4025 new = kmalloc(struct_size(new, entries
, size
), GFP_KERNEL
);
4032 /* Copy thresholds (if any) to new array */
4033 if (thresholds
->primary
) {
4034 memcpy(new->entries
, thresholds
->primary
->entries
, (size
- 1) *
4035 sizeof(struct mem_cgroup_threshold
));
4038 /* Add new threshold */
4039 new->entries
[size
- 1].eventfd
= eventfd
;
4040 new->entries
[size
- 1].threshold
= threshold
;
4042 /* Sort thresholds. Registering of new threshold isn't time-critical */
4043 sort(new->entries
, size
, sizeof(struct mem_cgroup_threshold
),
4044 compare_thresholds
, NULL
);
4046 /* Find current threshold */
4047 new->current_threshold
= -1;
4048 for (i
= 0; i
< size
; i
++) {
4049 if (new->entries
[i
].threshold
<= usage
) {
4051 * new->current_threshold will not be used until
4052 * rcu_assign_pointer(), so it's safe to increment
4055 ++new->current_threshold
;
4060 /* Free old spare buffer and save old primary buffer as spare */
4061 kfree(thresholds
->spare
);
4062 thresholds
->spare
= thresholds
->primary
;
4064 rcu_assign_pointer(thresholds
->primary
, new);
4066 /* To be sure that nobody uses thresholds */
4070 mutex_unlock(&memcg
->thresholds_lock
);
4075 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4076 struct eventfd_ctx
*eventfd
, const char *args
)
4078 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
4081 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4082 struct eventfd_ctx
*eventfd
, const char *args
)
4084 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
4087 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4088 struct eventfd_ctx
*eventfd
, enum res_type type
)
4090 struct mem_cgroup_thresholds
*thresholds
;
4091 struct mem_cgroup_threshold_ary
*new;
4092 unsigned long usage
;
4093 int i
, j
, size
, entries
;
4095 mutex_lock(&memcg
->thresholds_lock
);
4098 thresholds
= &memcg
->thresholds
;
4099 usage
= mem_cgroup_usage(memcg
, false);
4100 } else if (type
== _MEMSWAP
) {
4101 thresholds
= &memcg
->memsw_thresholds
;
4102 usage
= mem_cgroup_usage(memcg
, true);
4106 if (!thresholds
->primary
)
4109 /* Check if a threshold crossed before removing */
4110 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4112 /* Calculate new number of threshold */
4114 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4115 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4121 new = thresholds
->spare
;
4123 /* If no items related to eventfd have been cleared, nothing to do */
4127 /* Set thresholds array to NULL if we don't have thresholds */
4136 /* Copy thresholds and find current threshold */
4137 new->current_threshold
= -1;
4138 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4139 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4142 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4143 if (new->entries
[j
].threshold
<= usage
) {
4145 * new->current_threshold will not be used
4146 * until rcu_assign_pointer(), so it's safe to increment
4149 ++new->current_threshold
;
4155 /* Swap primary and spare array */
4156 thresholds
->spare
= thresholds
->primary
;
4158 rcu_assign_pointer(thresholds
->primary
, new);
4160 /* To be sure that nobody uses thresholds */
4163 /* If all events are unregistered, free the spare array */
4165 kfree(thresholds
->spare
);
4166 thresholds
->spare
= NULL
;
4169 mutex_unlock(&memcg
->thresholds_lock
);
4172 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4173 struct eventfd_ctx
*eventfd
)
4175 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
4178 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4179 struct eventfd_ctx
*eventfd
)
4181 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
4184 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
4185 struct eventfd_ctx
*eventfd
, const char *args
)
4187 struct mem_cgroup_eventfd_list
*event
;
4189 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4193 spin_lock(&memcg_oom_lock
);
4195 event
->eventfd
= eventfd
;
4196 list_add(&event
->list
, &memcg
->oom_notify
);
4198 /* already in OOM ? */
4199 if (memcg
->under_oom
)
4200 eventfd_signal(eventfd
, 1);
4201 spin_unlock(&memcg_oom_lock
);
4206 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
4207 struct eventfd_ctx
*eventfd
)
4209 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4211 spin_lock(&memcg_oom_lock
);
4213 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4214 if (ev
->eventfd
== eventfd
) {
4215 list_del(&ev
->list
);
4220 spin_unlock(&memcg_oom_lock
);
4223 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
4225 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(sf
);
4227 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
4228 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
4229 seq_printf(sf
, "oom_kill %lu\n",
4230 atomic_long_read(&memcg
->memory_events
[MEMCG_OOM_KILL
]));
4234 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
4235 struct cftype
*cft
, u64 val
)
4237 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4239 /* cannot set to root cgroup and only 0 and 1 are allowed */
4240 if (!css
->parent
|| !((val
== 0) || (val
== 1)))
4243 memcg
->oom_kill_disable
= val
;
4245 memcg_oom_recover(memcg
);
4250 #ifdef CONFIG_CGROUP_WRITEBACK
4252 #include <trace/events/writeback.h>
4254 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4256 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
4259 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4261 wb_domain_exit(&memcg
->cgwb_domain
);
4264 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4266 wb_domain_size_changed(&memcg
->cgwb_domain
);
4269 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
4271 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4273 if (!memcg
->css
.parent
)
4276 return &memcg
->cgwb_domain
;
4280 * idx can be of type enum memcg_stat_item or node_stat_item.
4281 * Keep in sync with memcg_exact_page().
4283 static unsigned long memcg_exact_page_state(struct mem_cgroup
*memcg
, int idx
)
4285 long x
= atomic_long_read(&memcg
->vmstats
[idx
]);
4288 for_each_online_cpu(cpu
)
4289 x
+= per_cpu_ptr(memcg
->vmstats_percpu
, cpu
)->stat
[idx
];
4296 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4297 * @wb: bdi_writeback in question
4298 * @pfilepages: out parameter for number of file pages
4299 * @pheadroom: out parameter for number of allocatable pages according to memcg
4300 * @pdirty: out parameter for number of dirty pages
4301 * @pwriteback: out parameter for number of pages under writeback
4303 * Determine the numbers of file, headroom, dirty, and writeback pages in
4304 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4305 * is a bit more involved.
4307 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4308 * headroom is calculated as the lowest headroom of itself and the
4309 * ancestors. Note that this doesn't consider the actual amount of
4310 * available memory in the system. The caller should further cap
4311 * *@pheadroom accordingly.
4313 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
4314 unsigned long *pheadroom
, unsigned long *pdirty
,
4315 unsigned long *pwriteback
)
4317 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4318 struct mem_cgroup
*parent
;
4320 *pdirty
= memcg_exact_page_state(memcg
, NR_FILE_DIRTY
);
4322 *pwriteback
= memcg_exact_page_state(memcg
, NR_WRITEBACK
);
4323 *pfilepages
= memcg_exact_page_state(memcg
, NR_INACTIVE_FILE
) +
4324 memcg_exact_page_state(memcg
, NR_ACTIVE_FILE
);
4325 *pheadroom
= PAGE_COUNTER_MAX
;
4327 while ((parent
= parent_mem_cgroup(memcg
))) {
4328 unsigned long ceiling
= min(READ_ONCE(memcg
->memory
.max
),
4329 READ_ONCE(memcg
->memory
.high
));
4330 unsigned long used
= page_counter_read(&memcg
->memory
);
4332 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
4338 * Foreign dirty flushing
4340 * There's an inherent mismatch between memcg and writeback. The former
4341 * trackes ownership per-page while the latter per-inode. This was a
4342 * deliberate design decision because honoring per-page ownership in the
4343 * writeback path is complicated, may lead to higher CPU and IO overheads
4344 * and deemed unnecessary given that write-sharing an inode across
4345 * different cgroups isn't a common use-case.
4347 * Combined with inode majority-writer ownership switching, this works well
4348 * enough in most cases but there are some pathological cases. For
4349 * example, let's say there are two cgroups A and B which keep writing to
4350 * different but confined parts of the same inode. B owns the inode and
4351 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4352 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4353 * triggering background writeback. A will be slowed down without a way to
4354 * make writeback of the dirty pages happen.
4356 * Conditions like the above can lead to a cgroup getting repatedly and
4357 * severely throttled after making some progress after each
4358 * dirty_expire_interval while the underyling IO device is almost
4361 * Solving this problem completely requires matching the ownership tracking
4362 * granularities between memcg and writeback in either direction. However,
4363 * the more egregious behaviors can be avoided by simply remembering the
4364 * most recent foreign dirtying events and initiating remote flushes on
4365 * them when local writeback isn't enough to keep the memory clean enough.
4367 * The following two functions implement such mechanism. When a foreign
4368 * page - a page whose memcg and writeback ownerships don't match - is
4369 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4370 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4371 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4372 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4373 * foreign bdi_writebacks which haven't expired. Both the numbers of
4374 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4375 * limited to MEMCG_CGWB_FRN_CNT.
4377 * The mechanism only remembers IDs and doesn't hold any object references.
4378 * As being wrong occasionally doesn't matter, updates and accesses to the
4379 * records are lockless and racy.
4381 void mem_cgroup_track_foreign_dirty_slowpath(struct page
*page
,
4382 struct bdi_writeback
*wb
)
4384 struct mem_cgroup
*memcg
= page
->mem_cgroup
;
4385 struct memcg_cgwb_frn
*frn
;
4386 u64 now
= get_jiffies_64();
4387 u64 oldest_at
= now
;
4391 trace_track_foreign_dirty(page
, wb
);
4394 * Pick the slot to use. If there is already a slot for @wb, keep
4395 * using it. If not replace the oldest one which isn't being
4398 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4399 frn
= &memcg
->cgwb_frn
[i
];
4400 if (frn
->bdi_id
== wb
->bdi
->id
&&
4401 frn
->memcg_id
== wb
->memcg_css
->id
)
4403 if (time_before64(frn
->at
, oldest_at
) &&
4404 atomic_read(&frn
->done
.cnt
) == 1) {
4406 oldest_at
= frn
->at
;
4410 if (i
< MEMCG_CGWB_FRN_CNT
) {
4412 * Re-using an existing one. Update timestamp lazily to
4413 * avoid making the cacheline hot. We want them to be
4414 * reasonably up-to-date and significantly shorter than
4415 * dirty_expire_interval as that's what expires the record.
4416 * Use the shorter of 1s and dirty_expire_interval / 8.
4418 unsigned long update_intv
=
4419 min_t(unsigned long, HZ
,
4420 msecs_to_jiffies(dirty_expire_interval
* 10) / 8);
4422 if (time_before64(frn
->at
, now
- update_intv
))
4424 } else if (oldest
>= 0) {
4425 /* replace the oldest free one */
4426 frn
= &memcg
->cgwb_frn
[oldest
];
4427 frn
->bdi_id
= wb
->bdi
->id
;
4428 frn
->memcg_id
= wb
->memcg_css
->id
;
4433 /* issue foreign writeback flushes for recorded foreign dirtying events */
4434 void mem_cgroup_flush_foreign(struct bdi_writeback
*wb
)
4436 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4437 unsigned long intv
= msecs_to_jiffies(dirty_expire_interval
* 10);
4438 u64 now
= jiffies_64
;
4441 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4442 struct memcg_cgwb_frn
*frn
= &memcg
->cgwb_frn
[i
];
4445 * If the record is older than dirty_expire_interval,
4446 * writeback on it has already started. No need to kick it
4447 * off again. Also, don't start a new one if there's
4448 * already one in flight.
4450 if (time_after64(frn
->at
, now
- intv
) &&
4451 atomic_read(&frn
->done
.cnt
) == 1) {
4453 trace_flush_foreign(wb
, frn
->bdi_id
, frn
->memcg_id
);
4454 cgroup_writeback_by_id(frn
->bdi_id
, frn
->memcg_id
, 0,
4455 WB_REASON_FOREIGN_FLUSH
,
4461 #else /* CONFIG_CGROUP_WRITEBACK */
4463 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4468 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4472 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4476 #endif /* CONFIG_CGROUP_WRITEBACK */
4479 * DO NOT USE IN NEW FILES.
4481 * "cgroup.event_control" implementation.
4483 * This is way over-engineered. It tries to support fully configurable
4484 * events for each user. Such level of flexibility is completely
4485 * unnecessary especially in the light of the planned unified hierarchy.
4487 * Please deprecate this and replace with something simpler if at all
4492 * Unregister event and free resources.
4494 * Gets called from workqueue.
4496 static void memcg_event_remove(struct work_struct
*work
)
4498 struct mem_cgroup_event
*event
=
4499 container_of(work
, struct mem_cgroup_event
, remove
);
4500 struct mem_cgroup
*memcg
= event
->memcg
;
4502 remove_wait_queue(event
->wqh
, &event
->wait
);
4504 event
->unregister_event(memcg
, event
->eventfd
);
4506 /* Notify userspace the event is going away. */
4507 eventfd_signal(event
->eventfd
, 1);
4509 eventfd_ctx_put(event
->eventfd
);
4511 css_put(&memcg
->css
);
4515 * Gets called on EPOLLHUP on eventfd when user closes it.
4517 * Called with wqh->lock held and interrupts disabled.
4519 static int memcg_event_wake(wait_queue_entry_t
*wait
, unsigned mode
,
4520 int sync
, void *key
)
4522 struct mem_cgroup_event
*event
=
4523 container_of(wait
, struct mem_cgroup_event
, wait
);
4524 struct mem_cgroup
*memcg
= event
->memcg
;
4525 __poll_t flags
= key_to_poll(key
);
4527 if (flags
& EPOLLHUP
) {
4529 * If the event has been detached at cgroup removal, we
4530 * can simply return knowing the other side will cleanup
4533 * We can't race against event freeing since the other
4534 * side will require wqh->lock via remove_wait_queue(),
4537 spin_lock(&memcg
->event_list_lock
);
4538 if (!list_empty(&event
->list
)) {
4539 list_del_init(&event
->list
);
4541 * We are in atomic context, but cgroup_event_remove()
4542 * may sleep, so we have to call it in workqueue.
4544 schedule_work(&event
->remove
);
4546 spin_unlock(&memcg
->event_list_lock
);
4552 static void memcg_event_ptable_queue_proc(struct file
*file
,
4553 wait_queue_head_t
*wqh
, poll_table
*pt
)
4555 struct mem_cgroup_event
*event
=
4556 container_of(pt
, struct mem_cgroup_event
, pt
);
4559 add_wait_queue(wqh
, &event
->wait
);
4563 * DO NOT USE IN NEW FILES.
4565 * Parse input and register new cgroup event handler.
4567 * Input must be in format '<event_fd> <control_fd> <args>'.
4568 * Interpretation of args is defined by control file implementation.
4570 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
4571 char *buf
, size_t nbytes
, loff_t off
)
4573 struct cgroup_subsys_state
*css
= of_css(of
);
4574 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4575 struct mem_cgroup_event
*event
;
4576 struct cgroup_subsys_state
*cfile_css
;
4577 unsigned int efd
, cfd
;
4584 buf
= strstrip(buf
);
4586 efd
= simple_strtoul(buf
, &endp
, 10);
4591 cfd
= simple_strtoul(buf
, &endp
, 10);
4592 if ((*endp
!= ' ') && (*endp
!= '\0'))
4596 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
4600 event
->memcg
= memcg
;
4601 INIT_LIST_HEAD(&event
->list
);
4602 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
4603 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
4604 INIT_WORK(&event
->remove
, memcg_event_remove
);
4612 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
4613 if (IS_ERR(event
->eventfd
)) {
4614 ret
= PTR_ERR(event
->eventfd
);
4621 goto out_put_eventfd
;
4624 /* the process need read permission on control file */
4625 /* AV: shouldn't we check that it's been opened for read instead? */
4626 ret
= inode_permission(file_inode(cfile
.file
), MAY_READ
);
4631 * Determine the event callbacks and set them in @event. This used
4632 * to be done via struct cftype but cgroup core no longer knows
4633 * about these events. The following is crude but the whole thing
4634 * is for compatibility anyway.
4636 * DO NOT ADD NEW FILES.
4638 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
4640 if (!strcmp(name
, "memory.usage_in_bytes")) {
4641 event
->register_event
= mem_cgroup_usage_register_event
;
4642 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
4643 } else if (!strcmp(name
, "memory.oom_control")) {
4644 event
->register_event
= mem_cgroup_oom_register_event
;
4645 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
4646 } else if (!strcmp(name
, "memory.pressure_level")) {
4647 event
->register_event
= vmpressure_register_event
;
4648 event
->unregister_event
= vmpressure_unregister_event
;
4649 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
4650 event
->register_event
= memsw_cgroup_usage_register_event
;
4651 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
4658 * Verify @cfile should belong to @css. Also, remaining events are
4659 * automatically removed on cgroup destruction but the removal is
4660 * asynchronous, so take an extra ref on @css.
4662 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
4663 &memory_cgrp_subsys
);
4665 if (IS_ERR(cfile_css
))
4667 if (cfile_css
!= css
) {
4672 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
4676 vfs_poll(efile
.file
, &event
->pt
);
4678 spin_lock(&memcg
->event_list_lock
);
4679 list_add(&event
->list
, &memcg
->event_list
);
4680 spin_unlock(&memcg
->event_list_lock
);
4692 eventfd_ctx_put(event
->eventfd
);
4701 static struct cftype mem_cgroup_legacy_files
[] = {
4703 .name
= "usage_in_bytes",
4704 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4705 .read_u64
= mem_cgroup_read_u64
,
4708 .name
= "max_usage_in_bytes",
4709 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4710 .write
= mem_cgroup_reset
,
4711 .read_u64
= mem_cgroup_read_u64
,
4714 .name
= "limit_in_bytes",
4715 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4716 .write
= mem_cgroup_write
,
4717 .read_u64
= mem_cgroup_read_u64
,
4720 .name
= "soft_limit_in_bytes",
4721 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4722 .write
= mem_cgroup_write
,
4723 .read_u64
= mem_cgroup_read_u64
,
4727 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4728 .write
= mem_cgroup_reset
,
4729 .read_u64
= mem_cgroup_read_u64
,
4733 .seq_show
= memcg_stat_show
,
4736 .name
= "force_empty",
4737 .write
= mem_cgroup_force_empty_write
,
4740 .name
= "use_hierarchy",
4741 .write_u64
= mem_cgroup_hierarchy_write
,
4742 .read_u64
= mem_cgroup_hierarchy_read
,
4745 .name
= "cgroup.event_control", /* XXX: for compat */
4746 .write
= memcg_write_event_control
,
4747 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
4750 .name
= "swappiness",
4751 .read_u64
= mem_cgroup_swappiness_read
,
4752 .write_u64
= mem_cgroup_swappiness_write
,
4755 .name
= "move_charge_at_immigrate",
4756 .read_u64
= mem_cgroup_move_charge_read
,
4757 .write_u64
= mem_cgroup_move_charge_write
,
4760 .name
= "oom_control",
4761 .seq_show
= mem_cgroup_oom_control_read
,
4762 .write_u64
= mem_cgroup_oom_control_write
,
4763 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4766 .name
= "pressure_level",
4770 .name
= "numa_stat",
4771 .seq_show
= memcg_numa_stat_show
,
4775 .name
= "kmem.limit_in_bytes",
4776 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4777 .write
= mem_cgroup_write
,
4778 .read_u64
= mem_cgroup_read_u64
,
4781 .name
= "kmem.usage_in_bytes",
4782 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4783 .read_u64
= mem_cgroup_read_u64
,
4786 .name
= "kmem.failcnt",
4787 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
4788 .write
= mem_cgroup_reset
,
4789 .read_u64
= mem_cgroup_read_u64
,
4792 .name
= "kmem.max_usage_in_bytes",
4793 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4794 .write
= mem_cgroup_reset
,
4795 .read_u64
= mem_cgroup_read_u64
,
4797 #if defined(CONFIG_MEMCG_KMEM) && \
4798 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
4800 .name
= "kmem.slabinfo",
4801 .seq_start
= memcg_slab_start
,
4802 .seq_next
= memcg_slab_next
,
4803 .seq_stop
= memcg_slab_stop
,
4804 .seq_show
= memcg_slab_show
,
4808 .name
= "kmem.tcp.limit_in_bytes",
4809 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4810 .write
= mem_cgroup_write
,
4811 .read_u64
= mem_cgroup_read_u64
,
4814 .name
= "kmem.tcp.usage_in_bytes",
4815 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4816 .read_u64
= mem_cgroup_read_u64
,
4819 .name
= "kmem.tcp.failcnt",
4820 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4821 .write
= mem_cgroup_reset
,
4822 .read_u64
= mem_cgroup_read_u64
,
4825 .name
= "kmem.tcp.max_usage_in_bytes",
4826 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4827 .write
= mem_cgroup_reset
,
4828 .read_u64
= mem_cgroup_read_u64
,
4830 { }, /* terminate */
4834 * Private memory cgroup IDR
4836 * Swap-out records and page cache shadow entries need to store memcg
4837 * references in constrained space, so we maintain an ID space that is
4838 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4839 * memory-controlled cgroups to 64k.
4841 * However, there usually are many references to the offline CSS after
4842 * the cgroup has been destroyed, such as page cache or reclaimable
4843 * slab objects, that don't need to hang on to the ID. We want to keep
4844 * those dead CSS from occupying IDs, or we might quickly exhaust the
4845 * relatively small ID space and prevent the creation of new cgroups
4846 * even when there are much fewer than 64k cgroups - possibly none.
4848 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4849 * be freed and recycled when it's no longer needed, which is usually
4850 * when the CSS is offlined.
4852 * The only exception to that are records of swapped out tmpfs/shmem
4853 * pages that need to be attributed to live ancestors on swapin. But
4854 * those references are manageable from userspace.
4857 static DEFINE_IDR(mem_cgroup_idr
);
4859 static void mem_cgroup_id_remove(struct mem_cgroup
*memcg
)
4861 if (memcg
->id
.id
> 0) {
4862 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
4867 static void __maybe_unused
mem_cgroup_id_get_many(struct mem_cgroup
*memcg
,
4870 refcount_add(n
, &memcg
->id
.ref
);
4873 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
4875 if (refcount_sub_and_test(n
, &memcg
->id
.ref
)) {
4876 mem_cgroup_id_remove(memcg
);
4878 /* Memcg ID pins CSS */
4879 css_put(&memcg
->css
);
4883 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
4885 mem_cgroup_id_put_many(memcg
, 1);
4889 * mem_cgroup_from_id - look up a memcg from a memcg id
4890 * @id: the memcg id to look up
4892 * Caller must hold rcu_read_lock().
4894 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
4896 WARN_ON_ONCE(!rcu_read_lock_held());
4897 return idr_find(&mem_cgroup_idr
, id
);
4900 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4902 struct mem_cgroup_per_node
*pn
;
4905 * This routine is called against possible nodes.
4906 * But it's BUG to call kmalloc() against offline node.
4908 * TODO: this routine can waste much memory for nodes which will
4909 * never be onlined. It's better to use memory hotplug callback
4912 if (!node_state(node
, N_NORMAL_MEMORY
))
4914 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
4918 pn
->lruvec_stat_local
= alloc_percpu(struct lruvec_stat
);
4919 if (!pn
->lruvec_stat_local
) {
4924 pn
->lruvec_stat_cpu
= alloc_percpu(struct lruvec_stat
);
4925 if (!pn
->lruvec_stat_cpu
) {
4926 free_percpu(pn
->lruvec_stat_local
);
4931 lruvec_init(&pn
->lruvec
);
4932 pn
->usage_in_excess
= 0;
4933 pn
->on_tree
= false;
4936 memcg
->nodeinfo
[node
] = pn
;
4940 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
4942 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
4947 free_percpu(pn
->lruvec_stat_cpu
);
4948 free_percpu(pn
->lruvec_stat_local
);
4952 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
4957 free_mem_cgroup_per_node_info(memcg
, node
);
4958 free_percpu(memcg
->vmstats_percpu
);
4959 free_percpu(memcg
->vmstats_local
);
4963 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
4965 memcg_wb_domain_exit(memcg
);
4967 * Flush percpu vmstats and vmevents to guarantee the value correctness
4968 * on parent's and all ancestor levels.
4970 memcg_flush_percpu_vmstats(memcg
);
4971 memcg_flush_percpu_vmevents(memcg
);
4972 __mem_cgroup_free(memcg
);
4975 static struct mem_cgroup
*mem_cgroup_alloc(void)
4977 struct mem_cgroup
*memcg
;
4980 int __maybe_unused i
;
4981 long error
= -ENOMEM
;
4983 size
= sizeof(struct mem_cgroup
);
4984 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
4986 memcg
= kzalloc(size
, GFP_KERNEL
);
4988 return ERR_PTR(error
);
4990 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
4991 1, MEM_CGROUP_ID_MAX
,
4993 if (memcg
->id
.id
< 0) {
4994 error
= memcg
->id
.id
;
4998 memcg
->vmstats_local
= alloc_percpu(struct memcg_vmstats_percpu
);
4999 if (!memcg
->vmstats_local
)
5002 memcg
->vmstats_percpu
= alloc_percpu(struct memcg_vmstats_percpu
);
5003 if (!memcg
->vmstats_percpu
)
5007 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
5010 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
5013 INIT_WORK(&memcg
->high_work
, high_work_func
);
5014 INIT_LIST_HEAD(&memcg
->oom_notify
);
5015 mutex_init(&memcg
->thresholds_lock
);
5016 spin_lock_init(&memcg
->move_lock
);
5017 vmpressure_init(&memcg
->vmpressure
);
5018 INIT_LIST_HEAD(&memcg
->event_list
);
5019 spin_lock_init(&memcg
->event_list_lock
);
5020 memcg
->socket_pressure
= jiffies
;
5021 #ifdef CONFIG_MEMCG_KMEM
5022 memcg
->kmemcg_id
= -1;
5024 #ifdef CONFIG_CGROUP_WRITEBACK
5025 INIT_LIST_HEAD(&memcg
->cgwb_list
);
5026 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5027 memcg
->cgwb_frn
[i
].done
=
5028 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq
);
5030 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5031 spin_lock_init(&memcg
->deferred_split_queue
.split_queue_lock
);
5032 INIT_LIST_HEAD(&memcg
->deferred_split_queue
.split_queue
);
5033 memcg
->deferred_split_queue
.split_queue_len
= 0;
5035 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
5038 mem_cgroup_id_remove(memcg
);
5039 __mem_cgroup_free(memcg
);
5040 return ERR_PTR(error
);
5043 static struct cgroup_subsys_state
* __ref
5044 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
5046 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
5047 struct mem_cgroup
*memcg
;
5048 long error
= -ENOMEM
;
5050 memcg
= mem_cgroup_alloc();
5052 return ERR_CAST(memcg
);
5054 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5055 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5056 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5058 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
5059 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
5061 if (parent
&& parent
->use_hierarchy
) {
5062 memcg
->use_hierarchy
= true;
5063 page_counter_init(&memcg
->memory
, &parent
->memory
);
5064 page_counter_init(&memcg
->swap
, &parent
->swap
);
5065 page_counter_init(&memcg
->memsw
, &parent
->memsw
);
5066 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
5067 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
5069 page_counter_init(&memcg
->memory
, NULL
);
5070 page_counter_init(&memcg
->swap
, NULL
);
5071 page_counter_init(&memcg
->memsw
, NULL
);
5072 page_counter_init(&memcg
->kmem
, NULL
);
5073 page_counter_init(&memcg
->tcpmem
, NULL
);
5075 * Deeper hierachy with use_hierarchy == false doesn't make
5076 * much sense so let cgroup subsystem know about this
5077 * unfortunate state in our controller.
5079 if (parent
!= root_mem_cgroup
)
5080 memory_cgrp_subsys
.broken_hierarchy
= true;
5083 /* The following stuff does not apply to the root */
5085 #ifdef CONFIG_MEMCG_KMEM
5086 INIT_LIST_HEAD(&memcg
->kmem_caches
);
5088 root_mem_cgroup
= memcg
;
5092 error
= memcg_online_kmem(memcg
);
5096 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5097 static_branch_inc(&memcg_sockets_enabled_key
);
5101 mem_cgroup_id_remove(memcg
);
5102 mem_cgroup_free(memcg
);
5103 return ERR_PTR(error
);
5106 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
5108 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5111 * A memcg must be visible for memcg_expand_shrinker_maps()
5112 * by the time the maps are allocated. So, we allocate maps
5113 * here, when for_each_mem_cgroup() can't skip it.
5115 if (memcg_alloc_shrinker_maps(memcg
)) {
5116 mem_cgroup_id_remove(memcg
);
5120 /* Online state pins memcg ID, memcg ID pins CSS */
5121 refcount_set(&memcg
->id
.ref
, 1);
5126 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
5128 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5129 struct mem_cgroup_event
*event
, *tmp
;
5132 * Unregister events and notify userspace.
5133 * Notify userspace about cgroup removing only after rmdir of cgroup
5134 * directory to avoid race between userspace and kernelspace.
5136 spin_lock(&memcg
->event_list_lock
);
5137 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
5138 list_del_init(&event
->list
);
5139 schedule_work(&event
->remove
);
5141 spin_unlock(&memcg
->event_list_lock
);
5143 page_counter_set_min(&memcg
->memory
, 0);
5144 page_counter_set_low(&memcg
->memory
, 0);
5146 memcg_offline_kmem(memcg
);
5147 wb_memcg_offline(memcg
);
5149 drain_all_stock(memcg
);
5151 mem_cgroup_id_put(memcg
);
5154 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
5156 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5158 invalidate_reclaim_iterators(memcg
);
5161 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
5163 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5164 int __maybe_unused i
;
5166 #ifdef CONFIG_CGROUP_WRITEBACK
5167 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5168 wb_wait_for_completion(&memcg
->cgwb_frn
[i
].done
);
5170 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5171 static_branch_dec(&memcg_sockets_enabled_key
);
5173 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
5174 static_branch_dec(&memcg_sockets_enabled_key
);
5176 vmpressure_cleanup(&memcg
->vmpressure
);
5177 cancel_work_sync(&memcg
->high_work
);
5178 mem_cgroup_remove_from_trees(memcg
);
5179 memcg_free_shrinker_maps(memcg
);
5180 memcg_free_kmem(memcg
);
5181 mem_cgroup_free(memcg
);
5185 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5186 * @css: the target css
5188 * Reset the states of the mem_cgroup associated with @css. This is
5189 * invoked when the userland requests disabling on the default hierarchy
5190 * but the memcg is pinned through dependency. The memcg should stop
5191 * applying policies and should revert to the vanilla state as it may be
5192 * made visible again.
5194 * The current implementation only resets the essential configurations.
5195 * This needs to be expanded to cover all the visible parts.
5197 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
5199 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5201 page_counter_set_max(&memcg
->memory
, PAGE_COUNTER_MAX
);
5202 page_counter_set_max(&memcg
->swap
, PAGE_COUNTER_MAX
);
5203 page_counter_set_max(&memcg
->memsw
, PAGE_COUNTER_MAX
);
5204 page_counter_set_max(&memcg
->kmem
, PAGE_COUNTER_MAX
);
5205 page_counter_set_max(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
5206 page_counter_set_min(&memcg
->memory
, 0);
5207 page_counter_set_low(&memcg
->memory
, 0);
5208 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5209 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5210 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5211 memcg_wb_domain_size_changed(memcg
);
5215 /* Handlers for move charge at task migration. */
5216 static int mem_cgroup_do_precharge(unsigned long count
)
5220 /* Try a single bulk charge without reclaim first, kswapd may wake */
5221 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
5223 mc
.precharge
+= count
;
5227 /* Try charges one by one with reclaim, but do not retry */
5229 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
5243 enum mc_target_type
{
5250 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
5251 unsigned long addr
, pte_t ptent
)
5253 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
5255 if (!page
|| !page_mapped(page
))
5257 if (PageAnon(page
)) {
5258 if (!(mc
.flags
& MOVE_ANON
))
5261 if (!(mc
.flags
& MOVE_FILE
))
5264 if (!get_page_unless_zero(page
))
5270 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5271 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5272 pte_t ptent
, swp_entry_t
*entry
)
5274 struct page
*page
= NULL
;
5275 swp_entry_t ent
= pte_to_swp_entry(ptent
);
5277 if (!(mc
.flags
& MOVE_ANON
) || non_swap_entry(ent
))
5281 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5282 * a device and because they are not accessible by CPU they are store
5283 * as special swap entry in the CPU page table.
5285 if (is_device_private_entry(ent
)) {
5286 page
= device_private_entry_to_page(ent
);
5288 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5289 * a refcount of 1 when free (unlike normal page)
5291 if (!page_ref_add_unless(page
, 1, 1))
5297 * Because lookup_swap_cache() updates some statistics counter,
5298 * we call find_get_page() with swapper_space directly.
5300 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
5301 entry
->val
= ent
.val
;
5306 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5307 pte_t ptent
, swp_entry_t
*entry
)
5313 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5314 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5316 struct page
*page
= NULL
;
5317 struct address_space
*mapping
;
5320 if (!vma
->vm_file
) /* anonymous vma */
5322 if (!(mc
.flags
& MOVE_FILE
))
5325 mapping
= vma
->vm_file
->f_mapping
;
5326 pgoff
= linear_page_index(vma
, addr
);
5328 /* page is moved even if it's not RSS of this task(page-faulted). */
5330 /* shmem/tmpfs may report page out on swap: account for that too. */
5331 if (shmem_mapping(mapping
)) {
5332 page
= find_get_entry(mapping
, pgoff
);
5333 if (xa_is_value(page
)) {
5334 swp_entry_t swp
= radix_to_swp_entry(page
);
5336 page
= find_get_page(swap_address_space(swp
),
5340 page
= find_get_page(mapping
, pgoff
);
5342 page
= find_get_page(mapping
, pgoff
);
5348 * mem_cgroup_move_account - move account of the page
5350 * @compound: charge the page as compound or small page
5351 * @from: mem_cgroup which the page is moved from.
5352 * @to: mem_cgroup which the page is moved to. @from != @to.
5354 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5356 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5359 static int mem_cgroup_move_account(struct page
*page
,
5361 struct mem_cgroup
*from
,
5362 struct mem_cgroup
*to
)
5364 struct lruvec
*from_vec
, *to_vec
;
5365 struct pglist_data
*pgdat
;
5366 unsigned int nr_pages
= compound
? hpage_nr_pages(page
) : 1;
5369 VM_BUG_ON(from
== to
);
5370 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5371 VM_BUG_ON(compound
&& !PageTransHuge(page
));
5374 * Prevent mem_cgroup_migrate() from looking at
5375 * page->mem_cgroup of its source page while we change it.
5378 if (!trylock_page(page
))
5382 if (page
->mem_cgroup
!= from
)
5385 pgdat
= page_pgdat(page
);
5386 from_vec
= mem_cgroup_lruvec(from
, pgdat
);
5387 to_vec
= mem_cgroup_lruvec(to
, pgdat
);
5389 lock_page_memcg(page
);
5391 if (PageAnon(page
)) {
5392 if (page_mapped(page
)) {
5393 __mod_lruvec_state(from_vec
, NR_ANON_MAPPED
, -nr_pages
);
5394 __mod_lruvec_state(to_vec
, NR_ANON_MAPPED
, nr_pages
);
5395 if (PageTransHuge(page
)) {
5396 __mod_lruvec_state(from_vec
, NR_ANON_THPS
,
5398 __mod_lruvec_state(to_vec
, NR_ANON_THPS
,
5404 __mod_lruvec_state(from_vec
, NR_FILE_PAGES
, -nr_pages
);
5405 __mod_lruvec_state(to_vec
, NR_FILE_PAGES
, nr_pages
);
5407 if (PageSwapBacked(page
)) {
5408 __mod_lruvec_state(from_vec
, NR_SHMEM
, -nr_pages
);
5409 __mod_lruvec_state(to_vec
, NR_SHMEM
, nr_pages
);
5412 if (page_mapped(page
)) {
5413 __mod_lruvec_state(from_vec
, NR_FILE_MAPPED
, -nr_pages
);
5414 __mod_lruvec_state(to_vec
, NR_FILE_MAPPED
, nr_pages
);
5417 if (PageDirty(page
)) {
5418 struct address_space
*mapping
= page_mapping(page
);
5420 if (mapping_cap_account_dirty(mapping
)) {
5421 __mod_lruvec_state(from_vec
, NR_FILE_DIRTY
,
5423 __mod_lruvec_state(to_vec
, NR_FILE_DIRTY
,
5429 if (PageWriteback(page
)) {
5430 __mod_lruvec_state(from_vec
, NR_WRITEBACK
, -nr_pages
);
5431 __mod_lruvec_state(to_vec
, NR_WRITEBACK
, nr_pages
);
5435 * All state has been migrated, let's switch to the new memcg.
5437 * It is safe to change page->mem_cgroup here because the page
5438 * is referenced, charged, isolated, and locked: we can't race
5439 * with (un)charging, migration, LRU putback, or anything else
5440 * that would rely on a stable page->mem_cgroup.
5442 * Note that lock_page_memcg is a memcg lock, not a page lock,
5443 * to save space. As soon as we switch page->mem_cgroup to a
5444 * new memcg that isn't locked, the above state can change
5445 * concurrently again. Make sure we're truly done with it.
5449 page
->mem_cgroup
= to
; /* caller should have done css_get */
5451 __unlock_page_memcg(from
);
5455 local_irq_disable();
5456 mem_cgroup_charge_statistics(to
, page
, nr_pages
);
5457 memcg_check_events(to
, page
);
5458 mem_cgroup_charge_statistics(from
, page
, -nr_pages
);
5459 memcg_check_events(from
, page
);
5468 * get_mctgt_type - get target type of moving charge
5469 * @vma: the vma the pte to be checked belongs
5470 * @addr: the address corresponding to the pte to be checked
5471 * @ptent: the pte to be checked
5472 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5475 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5476 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5477 * move charge. if @target is not NULL, the page is stored in target->page
5478 * with extra refcnt got(Callers should handle it).
5479 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5480 * target for charge migration. if @target is not NULL, the entry is stored
5482 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5483 * (so ZONE_DEVICE page and thus not on the lru).
5484 * For now we such page is charge like a regular page would be as for all
5485 * intent and purposes it is just special memory taking the place of a
5488 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5490 * Called with pte lock held.
5493 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5494 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5496 struct page
*page
= NULL
;
5497 enum mc_target_type ret
= MC_TARGET_NONE
;
5498 swp_entry_t ent
= { .val
= 0 };
5500 if (pte_present(ptent
))
5501 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5502 else if (is_swap_pte(ptent
))
5503 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
5504 else if (pte_none(ptent
))
5505 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5507 if (!page
&& !ent
.val
)
5511 * Do only loose check w/o serialization.
5512 * mem_cgroup_move_account() checks the page is valid or
5513 * not under LRU exclusion.
5515 if (page
->mem_cgroup
== mc
.from
) {
5516 ret
= MC_TARGET_PAGE
;
5517 if (is_device_private_page(page
))
5518 ret
= MC_TARGET_DEVICE
;
5520 target
->page
= page
;
5522 if (!ret
|| !target
)
5526 * There is a swap entry and a page doesn't exist or isn't charged.
5527 * But we cannot move a tail-page in a THP.
5529 if (ent
.val
&& !ret
&& (!page
|| !PageTransCompound(page
)) &&
5530 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
5531 ret
= MC_TARGET_SWAP
;
5538 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5540 * We don't consider PMD mapped swapping or file mapped pages because THP does
5541 * not support them for now.
5542 * Caller should make sure that pmd_trans_huge(pmd) is true.
5544 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5545 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5547 struct page
*page
= NULL
;
5548 enum mc_target_type ret
= MC_TARGET_NONE
;
5550 if (unlikely(is_swap_pmd(pmd
))) {
5551 VM_BUG_ON(thp_migration_supported() &&
5552 !is_pmd_migration_entry(pmd
));
5555 page
= pmd_page(pmd
);
5556 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
5557 if (!(mc
.flags
& MOVE_ANON
))
5559 if (page
->mem_cgroup
== mc
.from
) {
5560 ret
= MC_TARGET_PAGE
;
5563 target
->page
= page
;
5569 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5570 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5572 return MC_TARGET_NONE
;
5576 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5577 unsigned long addr
, unsigned long end
,
5578 struct mm_walk
*walk
)
5580 struct vm_area_struct
*vma
= walk
->vma
;
5584 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5587 * Note their can not be MC_TARGET_DEVICE for now as we do not
5588 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5589 * this might change.
5591 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5592 mc
.precharge
+= HPAGE_PMD_NR
;
5597 if (pmd_trans_unstable(pmd
))
5599 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5600 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5601 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5602 mc
.precharge
++; /* increment precharge temporarily */
5603 pte_unmap_unlock(pte
- 1, ptl
);
5609 static const struct mm_walk_ops precharge_walk_ops
= {
5610 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5613 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5615 unsigned long precharge
;
5618 walk_page_range(mm
, 0, mm
->highest_vm_end
, &precharge_walk_ops
, NULL
);
5619 mmap_read_unlock(mm
);
5621 precharge
= mc
.precharge
;
5627 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5629 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5631 VM_BUG_ON(mc
.moving_task
);
5632 mc
.moving_task
= current
;
5633 return mem_cgroup_do_precharge(precharge
);
5636 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5637 static void __mem_cgroup_clear_mc(void)
5639 struct mem_cgroup
*from
= mc
.from
;
5640 struct mem_cgroup
*to
= mc
.to
;
5642 /* we must uncharge all the leftover precharges from mc.to */
5644 cancel_charge(mc
.to
, mc
.precharge
);
5648 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5649 * we must uncharge here.
5651 if (mc
.moved_charge
) {
5652 cancel_charge(mc
.from
, mc
.moved_charge
);
5653 mc
.moved_charge
= 0;
5655 /* we must fixup refcnts and charges */
5656 if (mc
.moved_swap
) {
5657 /* uncharge swap account from the old cgroup */
5658 if (!mem_cgroup_is_root(mc
.from
))
5659 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
5661 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
5664 * we charged both to->memory and to->memsw, so we
5665 * should uncharge to->memory.
5667 if (!mem_cgroup_is_root(mc
.to
))
5668 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
5670 mem_cgroup_id_get_many(mc
.to
, mc
.moved_swap
);
5671 css_put_many(&mc
.to
->css
, mc
.moved_swap
);
5675 memcg_oom_recover(from
);
5676 memcg_oom_recover(to
);
5677 wake_up_all(&mc
.waitq
);
5680 static void mem_cgroup_clear_mc(void)
5682 struct mm_struct
*mm
= mc
.mm
;
5685 * we must clear moving_task before waking up waiters at the end of
5688 mc
.moving_task
= NULL
;
5689 __mem_cgroup_clear_mc();
5690 spin_lock(&mc
.lock
);
5694 spin_unlock(&mc
.lock
);
5699 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5701 struct cgroup_subsys_state
*css
;
5702 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
5703 struct mem_cgroup
*from
;
5704 struct task_struct
*leader
, *p
;
5705 struct mm_struct
*mm
;
5706 unsigned long move_flags
;
5709 /* charge immigration isn't supported on the default hierarchy */
5710 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5714 * Multi-process migrations only happen on the default hierarchy
5715 * where charge immigration is not used. Perform charge
5716 * immigration if @tset contains a leader and whine if there are
5720 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
5723 memcg
= mem_cgroup_from_css(css
);
5729 * We are now commited to this value whatever it is. Changes in this
5730 * tunable will only affect upcoming migrations, not the current one.
5731 * So we need to save it, and keep it going.
5733 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
5737 from
= mem_cgroup_from_task(p
);
5739 VM_BUG_ON(from
== memcg
);
5741 mm
= get_task_mm(p
);
5744 /* We move charges only when we move a owner of the mm */
5745 if (mm
->owner
== p
) {
5748 VM_BUG_ON(mc
.precharge
);
5749 VM_BUG_ON(mc
.moved_charge
);
5750 VM_BUG_ON(mc
.moved_swap
);
5752 spin_lock(&mc
.lock
);
5756 mc
.flags
= move_flags
;
5757 spin_unlock(&mc
.lock
);
5758 /* We set mc.moving_task later */
5760 ret
= mem_cgroup_precharge_mc(mm
);
5762 mem_cgroup_clear_mc();
5769 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5772 mem_cgroup_clear_mc();
5775 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
5776 unsigned long addr
, unsigned long end
,
5777 struct mm_walk
*walk
)
5780 struct vm_area_struct
*vma
= walk
->vma
;
5783 enum mc_target_type target_type
;
5784 union mc_target target
;
5787 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5789 if (mc
.precharge
< HPAGE_PMD_NR
) {
5793 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
5794 if (target_type
== MC_TARGET_PAGE
) {
5796 if (!isolate_lru_page(page
)) {
5797 if (!mem_cgroup_move_account(page
, true,
5799 mc
.precharge
-= HPAGE_PMD_NR
;
5800 mc
.moved_charge
+= HPAGE_PMD_NR
;
5802 putback_lru_page(page
);
5805 } else if (target_type
== MC_TARGET_DEVICE
) {
5807 if (!mem_cgroup_move_account(page
, true,
5809 mc
.precharge
-= HPAGE_PMD_NR
;
5810 mc
.moved_charge
+= HPAGE_PMD_NR
;
5818 if (pmd_trans_unstable(pmd
))
5821 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5822 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
5823 pte_t ptent
= *(pte
++);
5824 bool device
= false;
5830 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
5831 case MC_TARGET_DEVICE
:
5834 case MC_TARGET_PAGE
:
5837 * We can have a part of the split pmd here. Moving it
5838 * can be done but it would be too convoluted so simply
5839 * ignore such a partial THP and keep it in original
5840 * memcg. There should be somebody mapping the head.
5842 if (PageTransCompound(page
))
5844 if (!device
&& isolate_lru_page(page
))
5846 if (!mem_cgroup_move_account(page
, false,
5849 /* we uncharge from mc.from later. */
5853 putback_lru_page(page
);
5854 put
: /* get_mctgt_type() gets the page */
5857 case MC_TARGET_SWAP
:
5859 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
5861 /* we fixup refcnts and charges later. */
5869 pte_unmap_unlock(pte
- 1, ptl
);
5874 * We have consumed all precharges we got in can_attach().
5875 * We try charge one by one, but don't do any additional
5876 * charges to mc.to if we have failed in charge once in attach()
5879 ret
= mem_cgroup_do_precharge(1);
5887 static const struct mm_walk_ops charge_walk_ops
= {
5888 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
5891 static void mem_cgroup_move_charge(void)
5893 lru_add_drain_all();
5895 * Signal lock_page_memcg() to take the memcg's move_lock
5896 * while we're moving its pages to another memcg. Then wait
5897 * for already started RCU-only updates to finish.
5899 atomic_inc(&mc
.from
->moving_account
);
5902 if (unlikely(!mmap_read_trylock(mc
.mm
))) {
5904 * Someone who are holding the mmap_sem might be waiting in
5905 * waitq. So we cancel all extra charges, wake up all waiters,
5906 * and retry. Because we cancel precharges, we might not be able
5907 * to move enough charges, but moving charge is a best-effort
5908 * feature anyway, so it wouldn't be a big problem.
5910 __mem_cgroup_clear_mc();
5915 * When we have consumed all precharges and failed in doing
5916 * additional charge, the page walk just aborts.
5918 walk_page_range(mc
.mm
, 0, mc
.mm
->highest_vm_end
, &charge_walk_ops
,
5921 mmap_read_unlock(mc
.mm
);
5922 atomic_dec(&mc
.from
->moving_account
);
5925 static void mem_cgroup_move_task(void)
5928 mem_cgroup_move_charge();
5929 mem_cgroup_clear_mc();
5932 #else /* !CONFIG_MMU */
5933 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5937 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5940 static void mem_cgroup_move_task(void)
5946 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5947 * to verify whether we're attached to the default hierarchy on each mount
5950 static void mem_cgroup_bind(struct cgroup_subsys_state
*root_css
)
5953 * use_hierarchy is forced on the default hierarchy. cgroup core
5954 * guarantees that @root doesn't have any children, so turning it
5955 * on for the root memcg is enough.
5957 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5958 root_mem_cgroup
->use_hierarchy
= true;
5960 root_mem_cgroup
->use_hierarchy
= false;
5963 static int seq_puts_memcg_tunable(struct seq_file
*m
, unsigned long value
)
5965 if (value
== PAGE_COUNTER_MAX
)
5966 seq_puts(m
, "max\n");
5968 seq_printf(m
, "%llu\n", (u64
)value
* PAGE_SIZE
);
5973 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
5976 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5978 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
5981 static int memory_min_show(struct seq_file
*m
, void *v
)
5983 return seq_puts_memcg_tunable(m
,
5984 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.min
));
5987 static ssize_t
memory_min_write(struct kernfs_open_file
*of
,
5988 char *buf
, size_t nbytes
, loff_t off
)
5990 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
5994 buf
= strstrip(buf
);
5995 err
= page_counter_memparse(buf
, "max", &min
);
5999 page_counter_set_min(&memcg
->memory
, min
);
6004 static int memory_low_show(struct seq_file
*m
, void *v
)
6006 return seq_puts_memcg_tunable(m
,
6007 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.low
));
6010 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
6011 char *buf
, size_t nbytes
, loff_t off
)
6013 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6017 buf
= strstrip(buf
);
6018 err
= page_counter_memparse(buf
, "max", &low
);
6022 page_counter_set_low(&memcg
->memory
, low
);
6027 static int memory_high_show(struct seq_file
*m
, void *v
)
6029 return seq_puts_memcg_tunable(m
,
6030 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.high
));
6033 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
6034 char *buf
, size_t nbytes
, loff_t off
)
6036 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6037 unsigned int nr_retries
= MEM_CGROUP_RECLAIM_RETRIES
;
6038 bool drained
= false;
6042 buf
= strstrip(buf
);
6043 err
= page_counter_memparse(buf
, "max", &high
);
6047 page_counter_set_high(&memcg
->memory
, high
);
6050 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6051 unsigned long reclaimed
;
6053 if (nr_pages
<= high
)
6056 if (signal_pending(current
))
6060 drain_all_stock(memcg
);
6065 reclaimed
= try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
6068 if (!reclaimed
&& !nr_retries
--)
6075 static int memory_max_show(struct seq_file
*m
, void *v
)
6077 return seq_puts_memcg_tunable(m
,
6078 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.max
));
6081 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
6082 char *buf
, size_t nbytes
, loff_t off
)
6084 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6085 unsigned int nr_reclaims
= MEM_CGROUP_RECLAIM_RETRIES
;
6086 bool drained
= false;
6090 buf
= strstrip(buf
);
6091 err
= page_counter_memparse(buf
, "max", &max
);
6095 xchg(&memcg
->memory
.max
, max
);
6098 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6100 if (nr_pages
<= max
)
6103 if (signal_pending(current
))
6107 drain_all_stock(memcg
);
6113 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
6119 memcg_memory_event(memcg
, MEMCG_OOM
);
6120 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
6124 memcg_wb_domain_size_changed(memcg
);
6128 static void __memory_events_show(struct seq_file
*m
, atomic_long_t
*events
)
6130 seq_printf(m
, "low %lu\n", atomic_long_read(&events
[MEMCG_LOW
]));
6131 seq_printf(m
, "high %lu\n", atomic_long_read(&events
[MEMCG_HIGH
]));
6132 seq_printf(m
, "max %lu\n", atomic_long_read(&events
[MEMCG_MAX
]));
6133 seq_printf(m
, "oom %lu\n", atomic_long_read(&events
[MEMCG_OOM
]));
6134 seq_printf(m
, "oom_kill %lu\n",
6135 atomic_long_read(&events
[MEMCG_OOM_KILL
]));
6138 static int memory_events_show(struct seq_file
*m
, void *v
)
6140 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6142 __memory_events_show(m
, memcg
->memory_events
);
6146 static int memory_events_local_show(struct seq_file
*m
, void *v
)
6148 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6150 __memory_events_show(m
, memcg
->memory_events_local
);
6154 static int memory_stat_show(struct seq_file
*m
, void *v
)
6156 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6159 buf
= memory_stat_format(memcg
);
6167 static int memory_oom_group_show(struct seq_file
*m
, void *v
)
6169 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6171 seq_printf(m
, "%d\n", memcg
->oom_group
);
6176 static ssize_t
memory_oom_group_write(struct kernfs_open_file
*of
,
6177 char *buf
, size_t nbytes
, loff_t off
)
6179 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6182 buf
= strstrip(buf
);
6186 ret
= kstrtoint(buf
, 0, &oom_group
);
6190 if (oom_group
!= 0 && oom_group
!= 1)
6193 memcg
->oom_group
= oom_group
;
6198 static struct cftype memory_files
[] = {
6201 .flags
= CFTYPE_NOT_ON_ROOT
,
6202 .read_u64
= memory_current_read
,
6206 .flags
= CFTYPE_NOT_ON_ROOT
,
6207 .seq_show
= memory_min_show
,
6208 .write
= memory_min_write
,
6212 .flags
= CFTYPE_NOT_ON_ROOT
,
6213 .seq_show
= memory_low_show
,
6214 .write
= memory_low_write
,
6218 .flags
= CFTYPE_NOT_ON_ROOT
,
6219 .seq_show
= memory_high_show
,
6220 .write
= memory_high_write
,
6224 .flags
= CFTYPE_NOT_ON_ROOT
,
6225 .seq_show
= memory_max_show
,
6226 .write
= memory_max_write
,
6230 .flags
= CFTYPE_NOT_ON_ROOT
,
6231 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
6232 .seq_show
= memory_events_show
,
6235 .name
= "events.local",
6236 .flags
= CFTYPE_NOT_ON_ROOT
,
6237 .file_offset
= offsetof(struct mem_cgroup
, events_local_file
),
6238 .seq_show
= memory_events_local_show
,
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 * This function calculates an individual cgroup's effective
6271 * protection which is derived from its own memory.min/low, its
6272 * parent's and siblings' settings, as well as the actual memory
6273 * distribution in the tree.
6275 * The following rules apply to the effective protection values:
6277 * 1. At the first level of reclaim, effective protection is equal to
6278 * the declared protection in memory.min and memory.low.
6280 * 2. To enable safe delegation of the protection configuration, at
6281 * subsequent levels the effective protection is capped to the
6282 * parent's effective protection.
6284 * 3. To make complex and dynamic subtrees easier to configure, the
6285 * user is allowed to overcommit the declared protection at a given
6286 * level. If that is the case, the parent's effective protection is
6287 * distributed to the children in proportion to how much protection
6288 * they have declared and how much of it they are utilizing.
6290 * This makes distribution proportional, but also work-conserving:
6291 * if one cgroup claims much more protection than it uses memory,
6292 * the unused remainder is available to its siblings.
6294 * 4. Conversely, when the declared protection is undercommitted at a
6295 * given level, the distribution of the larger parental protection
6296 * budget is NOT proportional. A cgroup's protection from a sibling
6297 * is capped to its own memory.min/low setting.
6299 * 5. However, to allow protecting recursive subtrees from each other
6300 * without having to declare each individual cgroup's fixed share
6301 * of the ancestor's claim to protection, any unutilized -
6302 * "floating" - protection from up the tree is distributed in
6303 * proportion to each cgroup's *usage*. This makes the protection
6304 * neutral wrt sibling cgroups and lets them compete freely over
6305 * the shared parental protection budget, but it protects the
6306 * subtree as a whole from neighboring subtrees.
6308 * Note that 4. and 5. are not in conflict: 4. is about protecting
6309 * against immediate siblings whereas 5. is about protecting against
6310 * neighboring subtrees.
6312 static unsigned long effective_protection(unsigned long usage
,
6313 unsigned long parent_usage
,
6314 unsigned long setting
,
6315 unsigned long parent_effective
,
6316 unsigned long siblings_protected
)
6318 unsigned long protected;
6321 protected = min(usage
, setting
);
6323 * If all cgroups at this level combined claim and use more
6324 * protection then what the parent affords them, distribute
6325 * shares in proportion to utilization.
6327 * We are using actual utilization rather than the statically
6328 * claimed protection in order to be work-conserving: claimed
6329 * but unused protection is available to siblings that would
6330 * otherwise get a smaller chunk than what they claimed.
6332 if (siblings_protected
> parent_effective
)
6333 return protected * parent_effective
/ siblings_protected
;
6336 * Ok, utilized protection of all children is within what the
6337 * parent affords them, so we know whatever this child claims
6338 * and utilizes is effectively protected.
6340 * If there is unprotected usage beyond this value, reclaim
6341 * will apply pressure in proportion to that amount.
6343 * If there is unutilized protection, the cgroup will be fully
6344 * shielded from reclaim, but we do return a smaller value for
6345 * protection than what the group could enjoy in theory. This
6346 * is okay. With the overcommit distribution above, effective
6347 * protection is always dependent on how memory is actually
6348 * consumed among the siblings anyway.
6353 * If the children aren't claiming (all of) the protection
6354 * afforded to them by the parent, distribute the remainder in
6355 * proportion to the (unprotected) memory of each cgroup. That
6356 * way, cgroups that aren't explicitly prioritized wrt each
6357 * other compete freely over the allowance, but they are
6358 * collectively protected from neighboring trees.
6360 * We're using unprotected memory for the weight so that if
6361 * some cgroups DO claim explicit protection, we don't protect
6362 * the same bytes twice.
6364 if (!(cgrp_dfl_root
.flags
& CGRP_ROOT_MEMORY_RECURSIVE_PROT
))
6367 if (parent_effective
> siblings_protected
&& usage
> protected) {
6368 unsigned long unclaimed
;
6370 unclaimed
= parent_effective
- siblings_protected
;
6371 unclaimed
*= usage
- protected;
6372 unclaimed
/= parent_usage
- siblings_protected
;
6381 * mem_cgroup_protected - check if memory consumption is in the normal range
6382 * @root: the top ancestor of the sub-tree being checked
6383 * @memcg: the memory cgroup to check
6385 * WARNING: This function is not stateless! It can only be used as part
6386 * of a top-down tree iteration, not for isolated queries.
6388 * Returns one of the following:
6389 * MEMCG_PROT_NONE: cgroup memory is not protected
6390 * MEMCG_PROT_LOW: cgroup memory is protected as long there is
6391 * an unprotected supply of reclaimable memory from other cgroups.
6392 * MEMCG_PROT_MIN: cgroup memory is protected
6394 enum mem_cgroup_protection
mem_cgroup_protected(struct mem_cgroup
*root
,
6395 struct mem_cgroup
*memcg
)
6397 unsigned long usage
, parent_usage
;
6398 struct mem_cgroup
*parent
;
6400 if (mem_cgroup_disabled())
6401 return MEMCG_PROT_NONE
;
6404 root
= root_mem_cgroup
;
6406 return MEMCG_PROT_NONE
;
6408 usage
= page_counter_read(&memcg
->memory
);
6410 return MEMCG_PROT_NONE
;
6412 parent
= parent_mem_cgroup(memcg
);
6413 /* No parent means a non-hierarchical mode on v1 memcg */
6415 return MEMCG_PROT_NONE
;
6417 if (parent
== root
) {
6418 memcg
->memory
.emin
= READ_ONCE(memcg
->memory
.min
);
6419 memcg
->memory
.elow
= memcg
->memory
.low
;
6423 parent_usage
= page_counter_read(&parent
->memory
);
6425 WRITE_ONCE(memcg
->memory
.emin
, effective_protection(usage
, parent_usage
,
6426 READ_ONCE(memcg
->memory
.min
),
6427 READ_ONCE(parent
->memory
.emin
),
6428 atomic_long_read(&parent
->memory
.children_min_usage
)));
6430 WRITE_ONCE(memcg
->memory
.elow
, effective_protection(usage
, parent_usage
,
6431 memcg
->memory
.low
, READ_ONCE(parent
->memory
.elow
),
6432 atomic_long_read(&parent
->memory
.children_low_usage
)));
6435 if (usage
<= memcg
->memory
.emin
)
6436 return MEMCG_PROT_MIN
;
6437 else if (usage
<= memcg
->memory
.elow
)
6438 return MEMCG_PROT_LOW
;
6440 return MEMCG_PROT_NONE
;
6444 * mem_cgroup_charge - charge a newly allocated page to a cgroup
6445 * @page: page to charge
6446 * @mm: mm context of the victim
6447 * @gfp_mask: reclaim mode
6449 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6450 * pages according to @gfp_mask if necessary.
6452 * Returns 0 on success. Otherwise, an error code is returned.
6454 int mem_cgroup_charge(struct page
*page
, struct mm_struct
*mm
, gfp_t gfp_mask
)
6456 unsigned int nr_pages
= hpage_nr_pages(page
);
6457 struct mem_cgroup
*memcg
= NULL
;
6460 if (mem_cgroup_disabled())
6463 if (PageSwapCache(page
)) {
6464 swp_entry_t ent
= { .val
= page_private(page
), };
6468 * Every swap fault against a single page tries to charge the
6469 * page, bail as early as possible. shmem_unuse() encounters
6470 * already charged pages, too. page->mem_cgroup is protected
6471 * by the page lock, which serializes swap cache removal, which
6472 * in turn serializes uncharging.
6474 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
6475 if (compound_head(page
)->mem_cgroup
)
6478 id
= lookup_swap_cgroup_id(ent
);
6480 memcg
= mem_cgroup_from_id(id
);
6481 if (memcg
&& !css_tryget_online(&memcg
->css
))
6487 memcg
= get_mem_cgroup_from_mm(mm
);
6489 ret
= try_charge(memcg
, gfp_mask
, nr_pages
);
6493 commit_charge(page
, memcg
);
6495 local_irq_disable();
6496 mem_cgroup_charge_statistics(memcg
, page
, nr_pages
);
6497 memcg_check_events(memcg
, page
);
6500 if (PageSwapCache(page
)) {
6501 swp_entry_t entry
= { .val
= page_private(page
) };
6503 * The swap entry might not get freed for a long time,
6504 * let's not wait for it. The page already received a
6505 * memory+swap charge, drop the swap entry duplicate.
6507 mem_cgroup_uncharge_swap(entry
, nr_pages
);
6511 css_put(&memcg
->css
);
6516 struct uncharge_gather
{
6517 struct mem_cgroup
*memcg
;
6518 unsigned long nr_pages
;
6519 unsigned long pgpgout
;
6520 unsigned long nr_kmem
;
6521 struct page
*dummy_page
;
6524 static inline void uncharge_gather_clear(struct uncharge_gather
*ug
)
6526 memset(ug
, 0, sizeof(*ug
));
6529 static void uncharge_batch(const struct uncharge_gather
*ug
)
6531 unsigned long flags
;
6533 if (!mem_cgroup_is_root(ug
->memcg
)) {
6534 page_counter_uncharge(&ug
->memcg
->memory
, ug
->nr_pages
);
6535 if (do_memsw_account())
6536 page_counter_uncharge(&ug
->memcg
->memsw
, ug
->nr_pages
);
6537 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && ug
->nr_kmem
)
6538 page_counter_uncharge(&ug
->memcg
->kmem
, ug
->nr_kmem
);
6539 memcg_oom_recover(ug
->memcg
);
6542 local_irq_save(flags
);
6543 __count_memcg_events(ug
->memcg
, PGPGOUT
, ug
->pgpgout
);
6544 __this_cpu_add(ug
->memcg
->vmstats_percpu
->nr_page_events
, ug
->nr_pages
);
6545 memcg_check_events(ug
->memcg
, ug
->dummy_page
);
6546 local_irq_restore(flags
);
6548 if (!mem_cgroup_is_root(ug
->memcg
))
6549 css_put_many(&ug
->memcg
->css
, ug
->nr_pages
);
6552 static void uncharge_page(struct page
*page
, struct uncharge_gather
*ug
)
6554 unsigned long nr_pages
;
6556 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6558 if (!page
->mem_cgroup
)
6562 * Nobody should be changing or seriously looking at
6563 * page->mem_cgroup at this point, we have fully
6564 * exclusive access to the page.
6567 if (ug
->memcg
!= page
->mem_cgroup
) {
6570 uncharge_gather_clear(ug
);
6572 ug
->memcg
= page
->mem_cgroup
;
6575 nr_pages
= compound_nr(page
);
6576 ug
->nr_pages
+= nr_pages
;
6578 if (!PageKmemcg(page
)) {
6581 ug
->nr_kmem
+= nr_pages
;
6582 __ClearPageKmemcg(page
);
6585 ug
->dummy_page
= page
;
6586 page
->mem_cgroup
= NULL
;
6589 static void uncharge_list(struct list_head
*page_list
)
6591 struct uncharge_gather ug
;
6592 struct list_head
*next
;
6594 uncharge_gather_clear(&ug
);
6597 * Note that the list can be a single page->lru; hence the
6598 * do-while loop instead of a simple list_for_each_entry().
6600 next
= page_list
->next
;
6604 page
= list_entry(next
, struct page
, lru
);
6605 next
= page
->lru
.next
;
6607 uncharge_page(page
, &ug
);
6608 } while (next
!= page_list
);
6611 uncharge_batch(&ug
);
6615 * mem_cgroup_uncharge - uncharge a page
6616 * @page: page to uncharge
6618 * Uncharge a page previously charged with mem_cgroup_charge().
6620 void mem_cgroup_uncharge(struct page
*page
)
6622 struct uncharge_gather ug
;
6624 if (mem_cgroup_disabled())
6627 /* Don't touch page->lru of any random page, pre-check: */
6628 if (!page
->mem_cgroup
)
6631 uncharge_gather_clear(&ug
);
6632 uncharge_page(page
, &ug
);
6633 uncharge_batch(&ug
);
6637 * mem_cgroup_uncharge_list - uncharge a list of page
6638 * @page_list: list of pages to uncharge
6640 * Uncharge a list of pages previously charged with
6641 * mem_cgroup_charge().
6643 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
6645 if (mem_cgroup_disabled())
6648 if (!list_empty(page_list
))
6649 uncharge_list(page_list
);
6653 * mem_cgroup_migrate - charge a page's replacement
6654 * @oldpage: currently circulating page
6655 * @newpage: replacement page
6657 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6658 * be uncharged upon free.
6660 * Both pages must be locked, @newpage->mapping must be set up.
6662 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
6664 struct mem_cgroup
*memcg
;
6665 unsigned int nr_pages
;
6666 unsigned long flags
;
6668 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
6669 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
6670 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
6671 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
6674 if (mem_cgroup_disabled())
6677 /* Page cache replacement: new page already charged? */
6678 if (newpage
->mem_cgroup
)
6681 /* Swapcache readahead pages can get replaced before being charged */
6682 memcg
= oldpage
->mem_cgroup
;
6686 /* Force-charge the new page. The old one will be freed soon */
6687 nr_pages
= hpage_nr_pages(newpage
);
6689 page_counter_charge(&memcg
->memory
, nr_pages
);
6690 if (do_memsw_account())
6691 page_counter_charge(&memcg
->memsw
, nr_pages
);
6692 css_get_many(&memcg
->css
, nr_pages
);
6694 commit_charge(newpage
, memcg
);
6696 local_irq_save(flags
);
6697 mem_cgroup_charge_statistics(memcg
, newpage
, nr_pages
);
6698 memcg_check_events(memcg
, newpage
);
6699 local_irq_restore(flags
);
6702 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
6703 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
6705 void mem_cgroup_sk_alloc(struct sock
*sk
)
6707 struct mem_cgroup
*memcg
;
6709 if (!mem_cgroup_sockets_enabled
)
6712 /* Do not associate the sock with unrelated interrupted task's memcg. */
6717 memcg
= mem_cgroup_from_task(current
);
6718 if (memcg
== root_mem_cgroup
)
6720 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
6722 if (css_tryget(&memcg
->css
))
6723 sk
->sk_memcg
= memcg
;
6728 void mem_cgroup_sk_free(struct sock
*sk
)
6731 css_put(&sk
->sk_memcg
->css
);
6735 * mem_cgroup_charge_skmem - charge socket memory
6736 * @memcg: memcg to charge
6737 * @nr_pages: number of pages to charge
6739 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
6740 * @memcg's configured limit, %false if the charge had to be forced.
6742 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
6744 gfp_t gfp_mask
= GFP_KERNEL
;
6746 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
6747 struct page_counter
*fail
;
6749 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
6750 memcg
->tcpmem_pressure
= 0;
6753 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
6754 memcg
->tcpmem_pressure
= 1;
6758 /* Don't block in the packet receive path */
6760 gfp_mask
= GFP_NOWAIT
;
6762 mod_memcg_state(memcg
, MEMCG_SOCK
, nr_pages
);
6764 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
6767 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
6772 * mem_cgroup_uncharge_skmem - uncharge socket memory
6773 * @memcg: memcg to uncharge
6774 * @nr_pages: number of pages to uncharge
6776 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
6778 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
6779 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
6783 mod_memcg_state(memcg
, MEMCG_SOCK
, -nr_pages
);
6785 refill_stock(memcg
, nr_pages
);
6788 static int __init
cgroup_memory(char *s
)
6792 while ((token
= strsep(&s
, ",")) != NULL
) {
6795 if (!strcmp(token
, "nosocket"))
6796 cgroup_memory_nosocket
= true;
6797 if (!strcmp(token
, "nokmem"))
6798 cgroup_memory_nokmem
= true;
6802 __setup("cgroup.memory=", cgroup_memory
);
6805 * subsys_initcall() for memory controller.
6807 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
6808 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
6809 * basically everything that doesn't depend on a specific mem_cgroup structure
6810 * should be initialized from here.
6812 static int __init
mem_cgroup_init(void)
6816 #ifdef CONFIG_MEMCG_KMEM
6818 * Kmem cache creation is mostly done with the slab_mutex held,
6819 * so use a workqueue with limited concurrency to avoid stalling
6820 * all worker threads in case lots of cgroups are created and
6821 * destroyed simultaneously.
6823 memcg_kmem_cache_wq
= alloc_workqueue("memcg_kmem_cache", 0, 1);
6824 BUG_ON(!memcg_kmem_cache_wq
);
6827 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
6828 memcg_hotplug_cpu_dead
);
6830 for_each_possible_cpu(cpu
)
6831 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
6834 for_each_node(node
) {
6835 struct mem_cgroup_tree_per_node
*rtpn
;
6837 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
6838 node_online(node
) ? node
: NUMA_NO_NODE
);
6840 rtpn
->rb_root
= RB_ROOT
;
6841 rtpn
->rb_rightmost
= NULL
;
6842 spin_lock_init(&rtpn
->lock
);
6843 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
6848 subsys_initcall(mem_cgroup_init
);
6850 #ifdef CONFIG_MEMCG_SWAP
6851 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
6853 while (!refcount_inc_not_zero(&memcg
->id
.ref
)) {
6855 * The root cgroup cannot be destroyed, so it's refcount must
6858 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
6862 memcg
= parent_mem_cgroup(memcg
);
6864 memcg
= root_mem_cgroup
;
6870 * mem_cgroup_swapout - transfer a memsw charge to swap
6871 * @page: page whose memsw charge to transfer
6872 * @entry: swap entry to move the charge to
6874 * Transfer the memsw charge of @page to @entry.
6876 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
6878 struct mem_cgroup
*memcg
, *swap_memcg
;
6879 unsigned int nr_entries
;
6880 unsigned short oldid
;
6882 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6883 VM_BUG_ON_PAGE(page_count(page
), page
);
6885 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
6888 memcg
= page
->mem_cgroup
;
6890 /* Readahead page, never charged */
6895 * In case the memcg owning these pages has been offlined and doesn't
6896 * have an ID allocated to it anymore, charge the closest online
6897 * ancestor for the swap instead and transfer the memory+swap charge.
6899 swap_memcg
= mem_cgroup_id_get_online(memcg
);
6900 nr_entries
= hpage_nr_pages(page
);
6901 /* Get references for the tail pages, too */
6903 mem_cgroup_id_get_many(swap_memcg
, nr_entries
- 1);
6904 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
),
6906 VM_BUG_ON_PAGE(oldid
, page
);
6907 mod_memcg_state(swap_memcg
, MEMCG_SWAP
, nr_entries
);
6909 page
->mem_cgroup
= NULL
;
6911 if (!mem_cgroup_is_root(memcg
))
6912 page_counter_uncharge(&memcg
->memory
, nr_entries
);
6914 if (!cgroup_memory_noswap
&& memcg
!= swap_memcg
) {
6915 if (!mem_cgroup_is_root(swap_memcg
))
6916 page_counter_charge(&swap_memcg
->memsw
, nr_entries
);
6917 page_counter_uncharge(&memcg
->memsw
, nr_entries
);
6921 * Interrupts should be disabled here because the caller holds the
6922 * i_pages lock which is taken with interrupts-off. It is
6923 * important here to have the interrupts disabled because it is the
6924 * only synchronisation we have for updating the per-CPU variables.
6926 VM_BUG_ON(!irqs_disabled());
6927 mem_cgroup_charge_statistics(memcg
, page
, -nr_entries
);
6928 memcg_check_events(memcg
, page
);
6930 if (!mem_cgroup_is_root(memcg
))
6931 css_put_many(&memcg
->css
, nr_entries
);
6935 * mem_cgroup_try_charge_swap - try charging swap space for a page
6936 * @page: page being added to swap
6937 * @entry: swap entry to charge
6939 * Try to charge @page's memcg for the swap space at @entry.
6941 * Returns 0 on success, -ENOMEM on failure.
6943 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
6945 unsigned int nr_pages
= hpage_nr_pages(page
);
6946 struct page_counter
*counter
;
6947 struct mem_cgroup
*memcg
;
6948 unsigned short oldid
;
6950 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
6953 memcg
= page
->mem_cgroup
;
6955 /* Readahead page, never charged */
6960 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
6964 memcg
= mem_cgroup_id_get_online(memcg
);
6966 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
) &&
6967 !page_counter_try_charge(&memcg
->swap
, nr_pages
, &counter
)) {
6968 memcg_memory_event(memcg
, MEMCG_SWAP_MAX
);
6969 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
6970 mem_cgroup_id_put(memcg
);
6974 /* Get references for the tail pages, too */
6976 mem_cgroup_id_get_many(memcg
, nr_pages
- 1);
6977 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
), nr_pages
);
6978 VM_BUG_ON_PAGE(oldid
, page
);
6979 mod_memcg_state(memcg
, MEMCG_SWAP
, nr_pages
);
6985 * mem_cgroup_uncharge_swap - uncharge swap space
6986 * @entry: swap entry to uncharge
6987 * @nr_pages: the amount of swap space to uncharge
6989 void mem_cgroup_uncharge_swap(swp_entry_t entry
, unsigned int nr_pages
)
6991 struct mem_cgroup
*memcg
;
6994 id
= swap_cgroup_record(entry
, 0, nr_pages
);
6996 memcg
= mem_cgroup_from_id(id
);
6998 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
)) {
6999 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7000 page_counter_uncharge(&memcg
->swap
, nr_pages
);
7002 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
7004 mod_memcg_state(memcg
, MEMCG_SWAP
, -nr_pages
);
7005 mem_cgroup_id_put_many(memcg
, nr_pages
);
7010 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
7012 long nr_swap_pages
= get_nr_swap_pages();
7014 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7015 return nr_swap_pages
;
7016 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
7017 nr_swap_pages
= min_t(long, nr_swap_pages
,
7018 READ_ONCE(memcg
->swap
.max
) -
7019 page_counter_read(&memcg
->swap
));
7020 return nr_swap_pages
;
7023 bool mem_cgroup_swap_full(struct page
*page
)
7025 struct mem_cgroup
*memcg
;
7027 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
7031 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7034 memcg
= page
->mem_cgroup
;
7038 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
)) {
7039 unsigned long usage
= page_counter_read(&memcg
->swap
);
7041 if (usage
* 2 >= READ_ONCE(memcg
->swap
.high
) ||
7042 usage
* 2 >= READ_ONCE(memcg
->swap
.max
))
7049 static int __init
setup_swap_account(char *s
)
7051 if (!strcmp(s
, "1"))
7052 cgroup_memory_noswap
= 0;
7053 else if (!strcmp(s
, "0"))
7054 cgroup_memory_noswap
= 1;
7057 __setup("swapaccount=", setup_swap_account
);
7059 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
7062 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7064 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
7067 static int swap_high_show(struct seq_file
*m
, void *v
)
7069 return seq_puts_memcg_tunable(m
,
7070 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.high
));
7073 static ssize_t
swap_high_write(struct kernfs_open_file
*of
,
7074 char *buf
, size_t nbytes
, loff_t off
)
7076 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7080 buf
= strstrip(buf
);
7081 err
= page_counter_memparse(buf
, "max", &high
);
7085 page_counter_set_high(&memcg
->swap
, high
);
7090 static int swap_max_show(struct seq_file
*m
, void *v
)
7092 return seq_puts_memcg_tunable(m
,
7093 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.max
));
7096 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
7097 char *buf
, size_t nbytes
, loff_t off
)
7099 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7103 buf
= strstrip(buf
);
7104 err
= page_counter_memparse(buf
, "max", &max
);
7108 xchg(&memcg
->swap
.max
, max
);
7113 static int swap_events_show(struct seq_file
*m
, void *v
)
7115 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
7117 seq_printf(m
, "high %lu\n",
7118 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_HIGH
]));
7119 seq_printf(m
, "max %lu\n",
7120 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_MAX
]));
7121 seq_printf(m
, "fail %lu\n",
7122 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_FAIL
]));
7127 static struct cftype swap_files
[] = {
7129 .name
= "swap.current",
7130 .flags
= CFTYPE_NOT_ON_ROOT
,
7131 .read_u64
= swap_current_read
,
7134 .name
= "swap.high",
7135 .flags
= CFTYPE_NOT_ON_ROOT
,
7136 .seq_show
= swap_high_show
,
7137 .write
= swap_high_write
,
7141 .flags
= CFTYPE_NOT_ON_ROOT
,
7142 .seq_show
= swap_max_show
,
7143 .write
= swap_max_write
,
7146 .name
= "swap.events",
7147 .flags
= CFTYPE_NOT_ON_ROOT
,
7148 .file_offset
= offsetof(struct mem_cgroup
, swap_events_file
),
7149 .seq_show
= swap_events_show
,
7154 static struct cftype memsw_files
[] = {
7156 .name
= "memsw.usage_in_bytes",
7157 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
7158 .read_u64
= mem_cgroup_read_u64
,
7161 .name
= "memsw.max_usage_in_bytes",
7162 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
7163 .write
= mem_cgroup_reset
,
7164 .read_u64
= mem_cgroup_read_u64
,
7167 .name
= "memsw.limit_in_bytes",
7168 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
7169 .write
= mem_cgroup_write
,
7170 .read_u64
= mem_cgroup_read_u64
,
7173 .name
= "memsw.failcnt",
7174 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
7175 .write
= mem_cgroup_reset
,
7176 .read_u64
= mem_cgroup_read_u64
,
7178 { }, /* terminate */
7181 static int __init
mem_cgroup_swap_init(void)
7183 /* No memory control -> no swap control */
7184 if (mem_cgroup_disabled())
7185 cgroup_memory_noswap
= true;
7187 if (cgroup_memory_noswap
)
7190 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
, swap_files
));
7191 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
, memsw_files
));
7195 subsys_initcall(mem_cgroup_swap_init
);
7197 #endif /* CONFIG_MEMCG_SWAP */