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
24 * Per memcg lru locking
25 * Copyright (C) 2020 Alibaba, Inc, Alex Shi
28 #include <linux/page_counter.h>
29 #include <linux/memcontrol.h>
30 #include <linux/cgroup.h>
31 #include <linux/pagewalk.h>
32 #include <linux/sched/mm.h>
33 #include <linux/shmem_fs.h>
34 #include <linux/hugetlb.h>
35 #include <linux/pagemap.h>
36 #include <linux/vm_event_item.h>
37 #include <linux/smp.h>
38 #include <linux/page-flags.h>
39 #include <linux/backing-dev.h>
40 #include <linux/bit_spinlock.h>
41 #include <linux/rcupdate.h>
42 #include <linux/limits.h>
43 #include <linux/export.h>
44 #include <linux/mutex.h>
45 #include <linux/rbtree.h>
46 #include <linux/slab.h>
47 #include <linux/swap.h>
48 #include <linux/swapops.h>
49 #include <linux/spinlock.h>
50 #include <linux/eventfd.h>
51 #include <linux/poll.h>
52 #include <linux/sort.h>
54 #include <linux/seq_file.h>
55 #include <linux/vmpressure.h>
56 #include <linux/mm_inline.h>
57 #include <linux/swap_cgroup.h>
58 #include <linux/cpu.h>
59 #include <linux/oom.h>
60 #include <linux/lockdep.h>
61 #include <linux/file.h>
62 #include <linux/tracehook.h>
63 #include <linux/psi.h>
64 #include <linux/seq_buf.h>
70 #include <linux/uaccess.h>
72 #include <trace/events/vmscan.h>
74 struct cgroup_subsys memory_cgrp_subsys __read_mostly
;
75 EXPORT_SYMBOL(memory_cgrp_subsys
);
77 struct mem_cgroup
*root_mem_cgroup __read_mostly
;
79 /* Active memory cgroup to use from an interrupt context */
80 DEFINE_PER_CPU(struct mem_cgroup
*, int_active_memcg
);
81 EXPORT_PER_CPU_SYMBOL_GPL(int_active_memcg
);
83 /* Socket memory accounting disabled? */
84 static bool cgroup_memory_nosocket __ro_after_init
;
86 /* Kernel memory accounting disabled? */
87 bool cgroup_memory_nokmem __ro_after_init
;
89 /* Whether the swap controller is active */
90 #ifdef CONFIG_MEMCG_SWAP
91 bool cgroup_memory_noswap __ro_after_init
;
93 #define cgroup_memory_noswap 1
96 #ifdef CONFIG_CGROUP_WRITEBACK
97 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq
);
100 /* Whether legacy memory+swap accounting is active */
101 static bool do_memsw_account(void)
103 return !cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_noswap
;
106 /* memcg and lruvec stats flushing */
107 static void flush_memcg_stats_dwork(struct work_struct
*w
);
108 static DECLARE_DEFERRABLE_WORK(stats_flush_dwork
, flush_memcg_stats_dwork
);
109 static void flush_memcg_stats_work(struct work_struct
*w
);
110 static DECLARE_WORK(stats_flush_work
, flush_memcg_stats_work
);
111 static DEFINE_PER_CPU(unsigned int, stats_flush_threshold
);
112 static DEFINE_SPINLOCK(stats_flush_lock
);
114 #define THRESHOLDS_EVENTS_TARGET 128
115 #define SOFTLIMIT_EVENTS_TARGET 1024
118 * Cgroups above their limits are maintained in a RB-Tree, independent of
119 * their hierarchy representation
122 struct mem_cgroup_tree_per_node
{
123 struct rb_root rb_root
;
124 struct rb_node
*rb_rightmost
;
128 struct mem_cgroup_tree
{
129 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
132 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
135 struct mem_cgroup_eventfd_list
{
136 struct list_head list
;
137 struct eventfd_ctx
*eventfd
;
141 * cgroup_event represents events which userspace want to receive.
143 struct mem_cgroup_event
{
145 * memcg which the event belongs to.
147 struct mem_cgroup
*memcg
;
149 * eventfd to signal userspace about the event.
151 struct eventfd_ctx
*eventfd
;
153 * Each of these stored in a list by the cgroup.
155 struct list_head list
;
157 * register_event() callback will be used to add new userspace
158 * waiter for changes related to this event. Use eventfd_signal()
159 * on eventfd to send notification to userspace.
161 int (*register_event
)(struct mem_cgroup
*memcg
,
162 struct eventfd_ctx
*eventfd
, const char *args
);
164 * unregister_event() callback will be called when userspace closes
165 * the eventfd or on cgroup removing. This callback must be set,
166 * if you want provide notification functionality.
168 void (*unregister_event
)(struct mem_cgroup
*memcg
,
169 struct eventfd_ctx
*eventfd
);
171 * All fields below needed to unregister event when
172 * userspace closes eventfd.
175 wait_queue_head_t
*wqh
;
176 wait_queue_entry_t wait
;
177 struct work_struct remove
;
180 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
181 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
183 /* Stuffs for move charges at task migration. */
185 * Types of charges to be moved.
187 #define MOVE_ANON 0x1U
188 #define MOVE_FILE 0x2U
189 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
191 /* "mc" and its members are protected by cgroup_mutex */
192 static struct move_charge_struct
{
193 spinlock_t lock
; /* for from, to */
194 struct mm_struct
*mm
;
195 struct mem_cgroup
*from
;
196 struct mem_cgroup
*to
;
198 unsigned long precharge
;
199 unsigned long moved_charge
;
200 unsigned long moved_swap
;
201 struct task_struct
*moving_task
; /* a task moving charges */
202 wait_queue_head_t waitq
; /* a waitq for other context */
204 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
205 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
209 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
210 * limit reclaim to prevent infinite loops, if they ever occur.
212 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
213 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
215 /* for encoding cft->private value on file */
224 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
225 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
226 #define MEMFILE_ATTR(val) ((val) & 0xffff)
227 /* Used for OOM notifier */
228 #define OOM_CONTROL (0)
231 * Iteration constructs for visiting all cgroups (under a tree). If
232 * loops are exited prematurely (break), mem_cgroup_iter_break() must
233 * be used for reference counting.
235 #define for_each_mem_cgroup_tree(iter, root) \
236 for (iter = mem_cgroup_iter(root, NULL, NULL); \
238 iter = mem_cgroup_iter(root, iter, NULL))
240 #define for_each_mem_cgroup(iter) \
241 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
243 iter = mem_cgroup_iter(NULL, iter, NULL))
245 static inline bool should_force_charge(void)
247 return tsk_is_oom_victim(current
) || fatal_signal_pending(current
) ||
248 (current
->flags
& PF_EXITING
);
251 /* Some nice accessors for the vmpressure. */
252 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
255 memcg
= root_mem_cgroup
;
256 return &memcg
->vmpressure
;
259 struct mem_cgroup
*vmpressure_to_memcg(struct vmpressure
*vmpr
)
261 return container_of(vmpr
, struct mem_cgroup
, vmpressure
);
264 #ifdef CONFIG_MEMCG_KMEM
265 extern spinlock_t css_set_lock
;
267 bool mem_cgroup_kmem_disabled(void)
269 return cgroup_memory_nokmem
;
272 static void obj_cgroup_uncharge_pages(struct obj_cgroup
*objcg
,
273 unsigned int nr_pages
);
275 static void obj_cgroup_release(struct percpu_ref
*ref
)
277 struct obj_cgroup
*objcg
= container_of(ref
, struct obj_cgroup
, refcnt
);
278 unsigned int nr_bytes
;
279 unsigned int nr_pages
;
283 * At this point all allocated objects are freed, and
284 * objcg->nr_charged_bytes can't have an arbitrary byte value.
285 * However, it can be PAGE_SIZE or (x * PAGE_SIZE).
287 * The following sequence can lead to it:
288 * 1) CPU0: objcg == stock->cached_objcg
289 * 2) CPU1: we do a small allocation (e.g. 92 bytes),
290 * PAGE_SIZE bytes are charged
291 * 3) CPU1: a process from another memcg is allocating something,
292 * the stock if flushed,
293 * objcg->nr_charged_bytes = PAGE_SIZE - 92
294 * 5) CPU0: we do release this object,
295 * 92 bytes are added to stock->nr_bytes
296 * 6) CPU0: stock is flushed,
297 * 92 bytes are added to objcg->nr_charged_bytes
299 * In the result, nr_charged_bytes == PAGE_SIZE.
300 * This page will be uncharged in obj_cgroup_release().
302 nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
);
303 WARN_ON_ONCE(nr_bytes
& (PAGE_SIZE
- 1));
304 nr_pages
= nr_bytes
>> PAGE_SHIFT
;
307 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
309 spin_lock_irqsave(&css_set_lock
, flags
);
310 list_del(&objcg
->list
);
311 spin_unlock_irqrestore(&css_set_lock
, flags
);
313 percpu_ref_exit(ref
);
314 kfree_rcu(objcg
, rcu
);
317 static struct obj_cgroup
*obj_cgroup_alloc(void)
319 struct obj_cgroup
*objcg
;
322 objcg
= kzalloc(sizeof(struct obj_cgroup
), GFP_KERNEL
);
326 ret
= percpu_ref_init(&objcg
->refcnt
, obj_cgroup_release
, 0,
332 INIT_LIST_HEAD(&objcg
->list
);
336 static void memcg_reparent_objcgs(struct mem_cgroup
*memcg
,
337 struct mem_cgroup
*parent
)
339 struct obj_cgroup
*objcg
, *iter
;
341 objcg
= rcu_replace_pointer(memcg
->objcg
, NULL
, true);
343 spin_lock_irq(&css_set_lock
);
345 /* 1) Ready to reparent active objcg. */
346 list_add(&objcg
->list
, &memcg
->objcg_list
);
347 /* 2) Reparent active objcg and already reparented objcgs to parent. */
348 list_for_each_entry(iter
, &memcg
->objcg_list
, list
)
349 WRITE_ONCE(iter
->memcg
, parent
);
350 /* 3) Move already reparented objcgs to the parent's list */
351 list_splice(&memcg
->objcg_list
, &parent
->objcg_list
);
353 spin_unlock_irq(&css_set_lock
);
355 percpu_ref_kill(&objcg
->refcnt
);
359 * This will be used as a shrinker list's index.
360 * The main reason for not using cgroup id for this:
361 * this works better in sparse environments, where we have a lot of memcgs,
362 * but only a few kmem-limited. Or also, if we have, for instance, 200
363 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
364 * 200 entry array for that.
366 * The current size of the caches array is stored in memcg_nr_cache_ids. It
367 * will double each time we have to increase it.
369 static DEFINE_IDA(memcg_cache_ida
);
370 int memcg_nr_cache_ids
;
372 /* Protects memcg_nr_cache_ids */
373 static DECLARE_RWSEM(memcg_cache_ids_sem
);
375 void memcg_get_cache_ids(void)
377 down_read(&memcg_cache_ids_sem
);
380 void memcg_put_cache_ids(void)
382 up_read(&memcg_cache_ids_sem
);
386 * MIN_SIZE is different than 1, because we would like to avoid going through
387 * the alloc/free process all the time. In a small machine, 4 kmem-limited
388 * cgroups is a reasonable guess. In the future, it could be a parameter or
389 * tunable, but that is strictly not necessary.
391 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
392 * this constant directly from cgroup, but it is understandable that this is
393 * better kept as an internal representation in cgroup.c. In any case, the
394 * cgrp_id space is not getting any smaller, and we don't have to necessarily
395 * increase ours as well if it increases.
397 #define MEMCG_CACHES_MIN_SIZE 4
398 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
401 * A lot of the calls to the cache allocation functions are expected to be
402 * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
403 * conditional to this static branch, we'll have to allow modules that does
404 * kmem_cache_alloc and the such to see this symbol as well
406 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
407 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
411 * mem_cgroup_css_from_page - css of the memcg associated with a page
412 * @page: page of interest
414 * If memcg is bound to the default hierarchy, css of the memcg associated
415 * with @page is returned. The returned css remains associated with @page
416 * until it is released.
418 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
421 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
423 struct mem_cgroup
*memcg
;
425 memcg
= page_memcg(page
);
427 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
428 memcg
= root_mem_cgroup
;
434 * page_cgroup_ino - return inode number of the memcg a page is charged to
437 * Look up the closest online ancestor of the memory cgroup @page is charged to
438 * and return its inode number or 0 if @page is not charged to any cgroup. It
439 * is safe to call this function without holding a reference to @page.
441 * Note, this function is inherently racy, because there is nothing to prevent
442 * the cgroup inode from getting torn down and potentially reallocated a moment
443 * after page_cgroup_ino() returns, so it only should be used by callers that
444 * do not care (such as procfs interfaces).
446 ino_t
page_cgroup_ino(struct page
*page
)
448 struct mem_cgroup
*memcg
;
449 unsigned long ino
= 0;
452 memcg
= page_memcg_check(page
);
454 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
455 memcg
= parent_mem_cgroup(memcg
);
457 ino
= cgroup_ino(memcg
->css
.cgroup
);
462 static struct mem_cgroup_per_node
*
463 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
465 int nid
= page_to_nid(page
);
467 return memcg
->nodeinfo
[nid
];
470 static struct mem_cgroup_tree_per_node
*
471 soft_limit_tree_node(int nid
)
473 return soft_limit_tree
.rb_tree_per_node
[nid
];
476 static struct mem_cgroup_tree_per_node
*
477 soft_limit_tree_from_page(struct page
*page
)
479 int nid
= page_to_nid(page
);
481 return soft_limit_tree
.rb_tree_per_node
[nid
];
484 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
485 struct mem_cgroup_tree_per_node
*mctz
,
486 unsigned long new_usage_in_excess
)
488 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
489 struct rb_node
*parent
= NULL
;
490 struct mem_cgroup_per_node
*mz_node
;
491 bool rightmost
= true;
496 mz
->usage_in_excess
= new_usage_in_excess
;
497 if (!mz
->usage_in_excess
)
501 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
503 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
) {
512 mctz
->rb_rightmost
= &mz
->tree_node
;
514 rb_link_node(&mz
->tree_node
, parent
, p
);
515 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
519 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
520 struct mem_cgroup_tree_per_node
*mctz
)
525 if (&mz
->tree_node
== mctz
->rb_rightmost
)
526 mctz
->rb_rightmost
= rb_prev(&mz
->tree_node
);
528 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
532 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
533 struct mem_cgroup_tree_per_node
*mctz
)
537 spin_lock_irqsave(&mctz
->lock
, flags
);
538 __mem_cgroup_remove_exceeded(mz
, mctz
);
539 spin_unlock_irqrestore(&mctz
->lock
, flags
);
542 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
544 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
545 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
546 unsigned long excess
= 0;
548 if (nr_pages
> soft_limit
)
549 excess
= nr_pages
- soft_limit
;
554 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
556 unsigned long excess
;
557 struct mem_cgroup_per_node
*mz
;
558 struct mem_cgroup_tree_per_node
*mctz
;
560 mctz
= soft_limit_tree_from_page(page
);
564 * Necessary to update all ancestors when hierarchy is used.
565 * because their event counter is not touched.
567 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
568 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
569 excess
= soft_limit_excess(memcg
);
571 * We have to update the tree if mz is on RB-tree or
572 * mem is over its softlimit.
574 if (excess
|| mz
->on_tree
) {
577 spin_lock_irqsave(&mctz
->lock
, flags
);
578 /* if on-tree, remove it */
580 __mem_cgroup_remove_exceeded(mz
, mctz
);
582 * Insert again. mz->usage_in_excess will be updated.
583 * If excess is 0, no tree ops.
585 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
586 spin_unlock_irqrestore(&mctz
->lock
, flags
);
591 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
593 struct mem_cgroup_tree_per_node
*mctz
;
594 struct mem_cgroup_per_node
*mz
;
598 mz
= memcg
->nodeinfo
[nid
];
599 mctz
= soft_limit_tree_node(nid
);
601 mem_cgroup_remove_exceeded(mz
, mctz
);
605 static struct mem_cgroup_per_node
*
606 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
608 struct mem_cgroup_per_node
*mz
;
612 if (!mctz
->rb_rightmost
)
613 goto done
; /* Nothing to reclaim from */
615 mz
= rb_entry(mctz
->rb_rightmost
,
616 struct mem_cgroup_per_node
, tree_node
);
618 * Remove the node now but someone else can add it back,
619 * we will to add it back at the end of reclaim to its correct
620 * position in the tree.
622 __mem_cgroup_remove_exceeded(mz
, mctz
);
623 if (!soft_limit_excess(mz
->memcg
) ||
624 !css_tryget(&mz
->memcg
->css
))
630 static struct mem_cgroup_per_node
*
631 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
633 struct mem_cgroup_per_node
*mz
;
635 spin_lock_irq(&mctz
->lock
);
636 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
637 spin_unlock_irq(&mctz
->lock
);
642 * __mod_memcg_state - update cgroup memory statistics
643 * @memcg: the memory cgroup
644 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
645 * @val: delta to add to the counter, can be negative
647 void __mod_memcg_state(struct mem_cgroup
*memcg
, int idx
, int val
)
649 if (mem_cgroup_disabled())
652 __this_cpu_add(memcg
->vmstats_percpu
->state
[idx
], val
);
653 cgroup_rstat_updated(memcg
->css
.cgroup
, smp_processor_id());
656 /* idx can be of type enum memcg_stat_item or node_stat_item. */
657 static unsigned long memcg_page_state_local(struct mem_cgroup
*memcg
, int idx
)
662 for_each_possible_cpu(cpu
)
663 x
+= per_cpu(memcg
->vmstats_percpu
->state
[idx
], cpu
);
671 void __mod_memcg_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
674 struct mem_cgroup_per_node
*pn
;
675 struct mem_cgroup
*memcg
;
677 pn
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
681 __mod_memcg_state(memcg
, idx
, val
);
684 __this_cpu_add(pn
->lruvec_stats_percpu
->state
[idx
], val
);
685 if (!(__this_cpu_inc_return(stats_flush_threshold
) % MEMCG_CHARGE_BATCH
))
686 queue_work(system_unbound_wq
, &stats_flush_work
);
690 * __mod_lruvec_state - update lruvec memory statistics
691 * @lruvec: the lruvec
692 * @idx: the stat item
693 * @val: delta to add to the counter, can be negative
695 * The lruvec is the intersection of the NUMA node and a cgroup. This
696 * function updates the all three counters that are affected by a
697 * change of state at this level: per-node, per-cgroup, per-lruvec.
699 void __mod_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
703 __mod_node_page_state(lruvec_pgdat(lruvec
), idx
, val
);
705 /* Update memcg and lruvec */
706 if (!mem_cgroup_disabled())
707 __mod_memcg_lruvec_state(lruvec
, idx
, val
);
710 void __mod_lruvec_page_state(struct page
*page
, enum node_stat_item idx
,
713 struct page
*head
= compound_head(page
); /* rmap on tail pages */
714 struct mem_cgroup
*memcg
;
715 pg_data_t
*pgdat
= page_pgdat(page
);
716 struct lruvec
*lruvec
;
719 memcg
= page_memcg(head
);
720 /* Untracked pages have no memcg, no lruvec. Update only the node */
723 __mod_node_page_state(pgdat
, idx
, val
);
727 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
728 __mod_lruvec_state(lruvec
, idx
, val
);
731 EXPORT_SYMBOL(__mod_lruvec_page_state
);
733 void __mod_lruvec_kmem_state(void *p
, enum node_stat_item idx
, int val
)
735 pg_data_t
*pgdat
= page_pgdat(virt_to_page(p
));
736 struct mem_cgroup
*memcg
;
737 struct lruvec
*lruvec
;
740 memcg
= mem_cgroup_from_obj(p
);
743 * Untracked pages have no memcg, no lruvec. Update only the
744 * node. If we reparent the slab objects to the root memcg,
745 * when we free the slab object, we need to update the per-memcg
746 * vmstats to keep it correct for the root memcg.
749 __mod_node_page_state(pgdat
, idx
, val
);
751 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
752 __mod_lruvec_state(lruvec
, idx
, val
);
758 * mod_objcg_mlstate() may be called with irq enabled, so
759 * mod_memcg_lruvec_state() should be used.
761 static inline void mod_objcg_mlstate(struct obj_cgroup
*objcg
,
762 struct pglist_data
*pgdat
,
763 enum node_stat_item idx
, int nr
)
765 struct mem_cgroup
*memcg
;
766 struct lruvec
*lruvec
;
769 memcg
= obj_cgroup_memcg(objcg
);
770 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
771 mod_memcg_lruvec_state(lruvec
, idx
, nr
);
776 * __count_memcg_events - account VM events in a cgroup
777 * @memcg: the memory cgroup
778 * @idx: the event item
779 * @count: the number of events that occurred
781 void __count_memcg_events(struct mem_cgroup
*memcg
, enum vm_event_item idx
,
784 if (mem_cgroup_disabled())
787 __this_cpu_add(memcg
->vmstats_percpu
->events
[idx
], count
);
788 cgroup_rstat_updated(memcg
->css
.cgroup
, smp_processor_id());
791 static unsigned long memcg_events(struct mem_cgroup
*memcg
, int event
)
793 return READ_ONCE(memcg
->vmstats
.events
[event
]);
796 static unsigned long memcg_events_local(struct mem_cgroup
*memcg
, int event
)
801 for_each_possible_cpu(cpu
)
802 x
+= per_cpu(memcg
->vmstats_percpu
->events
[event
], cpu
);
806 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
810 /* pagein of a big page is an event. So, ignore page size */
812 __count_memcg_events(memcg
, PGPGIN
, 1);
814 __count_memcg_events(memcg
, PGPGOUT
, 1);
815 nr_pages
= -nr_pages
; /* for event */
818 __this_cpu_add(memcg
->vmstats_percpu
->nr_page_events
, nr_pages
);
821 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
822 enum mem_cgroup_events_target target
)
824 unsigned long val
, next
;
826 val
= __this_cpu_read(memcg
->vmstats_percpu
->nr_page_events
);
827 next
= __this_cpu_read(memcg
->vmstats_percpu
->targets
[target
]);
828 /* from time_after() in jiffies.h */
829 if ((long)(next
- val
) < 0) {
831 case MEM_CGROUP_TARGET_THRESH
:
832 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
834 case MEM_CGROUP_TARGET_SOFTLIMIT
:
835 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
840 __this_cpu_write(memcg
->vmstats_percpu
->targets
[target
], next
);
847 * Check events in order.
850 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
852 /* threshold event is triggered in finer grain than soft limit */
853 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
854 MEM_CGROUP_TARGET_THRESH
))) {
857 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
858 MEM_CGROUP_TARGET_SOFTLIMIT
);
859 mem_cgroup_threshold(memcg
);
860 if (unlikely(do_softlimit
))
861 mem_cgroup_update_tree(memcg
, page
);
865 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
868 * mm_update_next_owner() may clear mm->owner to NULL
869 * if it races with swapoff, page migration, etc.
870 * So this can be called with p == NULL.
875 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
877 EXPORT_SYMBOL(mem_cgroup_from_task
);
879 static __always_inline
struct mem_cgroup
*active_memcg(void)
882 return this_cpu_read(int_active_memcg
);
884 return current
->active_memcg
;
888 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
889 * @mm: mm from which memcg should be extracted. It can be NULL.
891 * Obtain a reference on mm->memcg and returns it if successful. If mm
892 * is NULL, then the memcg is chosen as follows:
893 * 1) The active memcg, if set.
894 * 2) current->mm->memcg, if available
896 * If mem_cgroup is disabled, NULL is returned.
898 struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
900 struct mem_cgroup
*memcg
;
902 if (mem_cgroup_disabled())
906 * Page cache insertions can happen without an
907 * actual mm context, e.g. during disk probing
908 * on boot, loopback IO, acct() writes etc.
910 * No need to css_get on root memcg as the reference
911 * counting is disabled on the root level in the
912 * cgroup core. See CSS_NO_REF.
915 memcg
= active_memcg();
916 if (unlikely(memcg
)) {
917 /* remote memcg must hold a ref */
918 css_get(&memcg
->css
);
923 return root_mem_cgroup
;
928 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
929 if (unlikely(!memcg
))
930 memcg
= root_mem_cgroup
;
931 } while (!css_tryget(&memcg
->css
));
935 EXPORT_SYMBOL(get_mem_cgroup_from_mm
);
937 static __always_inline
bool memcg_kmem_bypass(void)
939 /* Allow remote memcg charging from any context. */
940 if (unlikely(active_memcg()))
943 /* Memcg to charge can't be determined. */
944 if (!in_task() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
951 * mem_cgroup_iter - iterate over memory cgroup hierarchy
952 * @root: hierarchy root
953 * @prev: previously returned memcg, NULL on first invocation
954 * @reclaim: cookie for shared reclaim walks, NULL for full walks
956 * Returns references to children of the hierarchy below @root, or
957 * @root itself, or %NULL after a full round-trip.
959 * Caller must pass the return value in @prev on subsequent
960 * invocations for reference counting, or use mem_cgroup_iter_break()
961 * to cancel a hierarchy walk before the round-trip is complete.
963 * Reclaimers can specify a node in @reclaim to divide up the memcgs
964 * in the hierarchy among all concurrent reclaimers operating on the
967 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
968 struct mem_cgroup
*prev
,
969 struct mem_cgroup_reclaim_cookie
*reclaim
)
971 struct mem_cgroup_reclaim_iter
*iter
;
972 struct cgroup_subsys_state
*css
= NULL
;
973 struct mem_cgroup
*memcg
= NULL
;
974 struct mem_cgroup
*pos
= NULL
;
976 if (mem_cgroup_disabled())
980 root
= root_mem_cgroup
;
982 if (prev
&& !reclaim
)
988 struct mem_cgroup_per_node
*mz
;
990 mz
= root
->nodeinfo
[reclaim
->pgdat
->node_id
];
993 if (prev
&& reclaim
->generation
!= iter
->generation
)
997 pos
= READ_ONCE(iter
->position
);
998 if (!pos
|| css_tryget(&pos
->css
))
1001 * css reference reached zero, so iter->position will
1002 * be cleared by ->css_released. However, we should not
1003 * rely on this happening soon, because ->css_released
1004 * is called from a work queue, and by busy-waiting we
1005 * might block it. So we clear iter->position right
1008 (void)cmpxchg(&iter
->position
, pos
, NULL
);
1016 css
= css_next_descendant_pre(css
, &root
->css
);
1019 * Reclaimers share the hierarchy walk, and a
1020 * new one might jump in right at the end of
1021 * the hierarchy - make sure they see at least
1022 * one group and restart from the beginning.
1030 * Verify the css and acquire a reference. The root
1031 * is provided by the caller, so we know it's alive
1032 * and kicking, and don't take an extra reference.
1034 memcg
= mem_cgroup_from_css(css
);
1036 if (css
== &root
->css
)
1039 if (css_tryget(css
))
1047 * The position could have already been updated by a competing
1048 * thread, so check that the value hasn't changed since we read
1049 * it to avoid reclaiming from the same cgroup twice.
1051 (void)cmpxchg(&iter
->position
, pos
, memcg
);
1059 reclaim
->generation
= iter
->generation
;
1064 if (prev
&& prev
!= root
)
1065 css_put(&prev
->css
);
1071 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1072 * @root: hierarchy root
1073 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1075 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1076 struct mem_cgroup
*prev
)
1079 root
= root_mem_cgroup
;
1080 if (prev
&& prev
!= root
)
1081 css_put(&prev
->css
);
1084 static void __invalidate_reclaim_iterators(struct mem_cgroup
*from
,
1085 struct mem_cgroup
*dead_memcg
)
1087 struct mem_cgroup_reclaim_iter
*iter
;
1088 struct mem_cgroup_per_node
*mz
;
1091 for_each_node(nid
) {
1092 mz
= from
->nodeinfo
[nid
];
1094 cmpxchg(&iter
->position
, dead_memcg
, NULL
);
1098 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
1100 struct mem_cgroup
*memcg
= dead_memcg
;
1101 struct mem_cgroup
*last
;
1104 __invalidate_reclaim_iterators(memcg
, dead_memcg
);
1106 } while ((memcg
= parent_mem_cgroup(memcg
)));
1109 * When cgruop1 non-hierarchy mode is used,
1110 * parent_mem_cgroup() does not walk all the way up to the
1111 * cgroup root (root_mem_cgroup). So we have to handle
1112 * dead_memcg from cgroup root separately.
1114 if (last
!= root_mem_cgroup
)
1115 __invalidate_reclaim_iterators(root_mem_cgroup
,
1120 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1121 * @memcg: hierarchy root
1122 * @fn: function to call for each task
1123 * @arg: argument passed to @fn
1125 * This function iterates over tasks attached to @memcg or to any of its
1126 * descendants and calls @fn for each task. If @fn returns a non-zero
1127 * value, the function breaks the iteration loop and returns the value.
1128 * Otherwise, it will iterate over all tasks and return 0.
1130 * This function must not be called for the root memory cgroup.
1132 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
1133 int (*fn
)(struct task_struct
*, void *), void *arg
)
1135 struct mem_cgroup
*iter
;
1138 BUG_ON(memcg
== root_mem_cgroup
);
1140 for_each_mem_cgroup_tree(iter
, memcg
) {
1141 struct css_task_iter it
;
1142 struct task_struct
*task
;
1144 css_task_iter_start(&iter
->css
, CSS_TASK_ITER_PROCS
, &it
);
1145 while (!ret
&& (task
= css_task_iter_next(&it
)))
1146 ret
= fn(task
, arg
);
1147 css_task_iter_end(&it
);
1149 mem_cgroup_iter_break(memcg
, iter
);
1156 #ifdef CONFIG_DEBUG_VM
1157 void lruvec_memcg_debug(struct lruvec
*lruvec
, struct page
*page
)
1159 struct mem_cgroup
*memcg
;
1161 if (mem_cgroup_disabled())
1164 memcg
= page_memcg(page
);
1167 VM_BUG_ON_PAGE(lruvec_memcg(lruvec
) != root_mem_cgroup
, page
);
1169 VM_BUG_ON_PAGE(lruvec_memcg(lruvec
) != memcg
, page
);
1174 * lock_page_lruvec - lock and return lruvec for a given page.
1177 * These functions are safe to use under any of the following conditions:
1180 * - lock_page_memcg()
1181 * - page->_refcount is zero
1183 struct lruvec
*lock_page_lruvec(struct page
*page
)
1185 struct lruvec
*lruvec
;
1187 lruvec
= mem_cgroup_page_lruvec(page
);
1188 spin_lock(&lruvec
->lru_lock
);
1190 lruvec_memcg_debug(lruvec
, page
);
1195 struct lruvec
*lock_page_lruvec_irq(struct page
*page
)
1197 struct lruvec
*lruvec
;
1199 lruvec
= mem_cgroup_page_lruvec(page
);
1200 spin_lock_irq(&lruvec
->lru_lock
);
1202 lruvec_memcg_debug(lruvec
, page
);
1207 struct lruvec
*lock_page_lruvec_irqsave(struct page
*page
, unsigned long *flags
)
1209 struct lruvec
*lruvec
;
1211 lruvec
= mem_cgroup_page_lruvec(page
);
1212 spin_lock_irqsave(&lruvec
->lru_lock
, *flags
);
1214 lruvec_memcg_debug(lruvec
, page
);
1220 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1221 * @lruvec: mem_cgroup per zone lru vector
1222 * @lru: index of lru list the page is sitting on
1223 * @zid: zone id of the accounted pages
1224 * @nr_pages: positive when adding or negative when removing
1226 * This function must be called under lru_lock, just before a page is added
1227 * to or just after a page is removed from an lru list (that ordering being
1228 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1230 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1231 int zid
, int nr_pages
)
1233 struct mem_cgroup_per_node
*mz
;
1234 unsigned long *lru_size
;
1237 if (mem_cgroup_disabled())
1240 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1241 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1244 *lru_size
+= nr_pages
;
1247 if (WARN_ONCE(size
< 0,
1248 "%s(%p, %d, %d): lru_size %ld\n",
1249 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1255 *lru_size
+= nr_pages
;
1259 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1260 * @memcg: the memory cgroup
1262 * Returns the maximum amount of memory @mem can be charged with, in
1265 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1267 unsigned long margin
= 0;
1268 unsigned long count
;
1269 unsigned long limit
;
1271 count
= page_counter_read(&memcg
->memory
);
1272 limit
= READ_ONCE(memcg
->memory
.max
);
1274 margin
= limit
- count
;
1276 if (do_memsw_account()) {
1277 count
= page_counter_read(&memcg
->memsw
);
1278 limit
= READ_ONCE(memcg
->memsw
.max
);
1280 margin
= min(margin
, limit
- count
);
1289 * A routine for checking "mem" is under move_account() or not.
1291 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1292 * moving cgroups. This is for waiting at high-memory pressure
1295 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1297 struct mem_cgroup
*from
;
1298 struct mem_cgroup
*to
;
1301 * Unlike task_move routines, we access mc.to, mc.from not under
1302 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1304 spin_lock(&mc
.lock
);
1310 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1311 mem_cgroup_is_descendant(to
, memcg
);
1313 spin_unlock(&mc
.lock
);
1317 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1319 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1320 if (mem_cgroup_under_move(memcg
)) {
1322 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1323 /* moving charge context might have finished. */
1326 finish_wait(&mc
.waitq
, &wait
);
1333 struct memory_stat
{
1338 static const struct memory_stat memory_stats
[] = {
1339 { "anon", NR_ANON_MAPPED
},
1340 { "file", NR_FILE_PAGES
},
1341 { "kernel_stack", NR_KERNEL_STACK_KB
},
1342 { "pagetables", NR_PAGETABLE
},
1343 { "percpu", MEMCG_PERCPU_B
},
1344 { "sock", MEMCG_SOCK
},
1345 { "shmem", NR_SHMEM
},
1346 { "file_mapped", NR_FILE_MAPPED
},
1347 { "file_dirty", NR_FILE_DIRTY
},
1348 { "file_writeback", NR_WRITEBACK
},
1350 { "swapcached", NR_SWAPCACHE
},
1352 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1353 { "anon_thp", NR_ANON_THPS
},
1354 { "file_thp", NR_FILE_THPS
},
1355 { "shmem_thp", NR_SHMEM_THPS
},
1357 { "inactive_anon", NR_INACTIVE_ANON
},
1358 { "active_anon", NR_ACTIVE_ANON
},
1359 { "inactive_file", NR_INACTIVE_FILE
},
1360 { "active_file", NR_ACTIVE_FILE
},
1361 { "unevictable", NR_UNEVICTABLE
},
1362 { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B
},
1363 { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B
},
1365 /* The memory events */
1366 { "workingset_refault_anon", WORKINGSET_REFAULT_ANON
},
1367 { "workingset_refault_file", WORKINGSET_REFAULT_FILE
},
1368 { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON
},
1369 { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE
},
1370 { "workingset_restore_anon", WORKINGSET_RESTORE_ANON
},
1371 { "workingset_restore_file", WORKINGSET_RESTORE_FILE
},
1372 { "workingset_nodereclaim", WORKINGSET_NODERECLAIM
},
1375 /* Translate stat items to the correct unit for memory.stat output */
1376 static int memcg_page_state_unit(int item
)
1379 case MEMCG_PERCPU_B
:
1380 case NR_SLAB_RECLAIMABLE_B
:
1381 case NR_SLAB_UNRECLAIMABLE_B
:
1382 case WORKINGSET_REFAULT_ANON
:
1383 case WORKINGSET_REFAULT_FILE
:
1384 case WORKINGSET_ACTIVATE_ANON
:
1385 case WORKINGSET_ACTIVATE_FILE
:
1386 case WORKINGSET_RESTORE_ANON
:
1387 case WORKINGSET_RESTORE_FILE
:
1388 case WORKINGSET_NODERECLAIM
:
1390 case NR_KERNEL_STACK_KB
:
1397 static inline unsigned long memcg_page_state_output(struct mem_cgroup
*memcg
,
1400 return memcg_page_state(memcg
, item
) * memcg_page_state_unit(item
);
1403 static char *memory_stat_format(struct mem_cgroup
*memcg
)
1408 seq_buf_init(&s
, kmalloc(PAGE_SIZE
, GFP_KERNEL
), PAGE_SIZE
);
1413 * Provide statistics on the state of the memory subsystem as
1414 * well as cumulative event counters that show past behavior.
1416 * This list is ordered following a combination of these gradients:
1417 * 1) generic big picture -> specifics and details
1418 * 2) reflecting userspace activity -> reflecting kernel heuristics
1420 * Current memory state:
1422 cgroup_rstat_flush(memcg
->css
.cgroup
);
1424 for (i
= 0; i
< ARRAY_SIZE(memory_stats
); i
++) {
1427 size
= memcg_page_state_output(memcg
, memory_stats
[i
].idx
);
1428 seq_buf_printf(&s
, "%s %llu\n", memory_stats
[i
].name
, size
);
1430 if (unlikely(memory_stats
[i
].idx
== NR_SLAB_UNRECLAIMABLE_B
)) {
1431 size
+= memcg_page_state_output(memcg
,
1432 NR_SLAB_RECLAIMABLE_B
);
1433 seq_buf_printf(&s
, "slab %llu\n", size
);
1437 /* Accumulated memory events */
1439 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGFAULT
),
1440 memcg_events(memcg
, PGFAULT
));
1441 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGMAJFAULT
),
1442 memcg_events(memcg
, PGMAJFAULT
));
1443 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGREFILL
),
1444 memcg_events(memcg
, PGREFILL
));
1445 seq_buf_printf(&s
, "pgscan %lu\n",
1446 memcg_events(memcg
, PGSCAN_KSWAPD
) +
1447 memcg_events(memcg
, PGSCAN_DIRECT
));
1448 seq_buf_printf(&s
, "pgsteal %lu\n",
1449 memcg_events(memcg
, PGSTEAL_KSWAPD
) +
1450 memcg_events(memcg
, PGSTEAL_DIRECT
));
1451 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGACTIVATE
),
1452 memcg_events(memcg
, PGACTIVATE
));
1453 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGDEACTIVATE
),
1454 memcg_events(memcg
, PGDEACTIVATE
));
1455 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREE
),
1456 memcg_events(memcg
, PGLAZYFREE
));
1457 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREED
),
1458 memcg_events(memcg
, PGLAZYFREED
));
1460 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1461 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC
),
1462 memcg_events(memcg
, THP_FAULT_ALLOC
));
1463 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC
),
1464 memcg_events(memcg
, THP_COLLAPSE_ALLOC
));
1465 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1467 /* The above should easily fit into one page */
1468 WARN_ON_ONCE(seq_buf_has_overflowed(&s
));
1473 #define K(x) ((x) << (PAGE_SHIFT-10))
1475 * mem_cgroup_print_oom_context: Print OOM information relevant to
1476 * memory controller.
1477 * @memcg: The memory cgroup that went over limit
1478 * @p: Task that is going to be killed
1480 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1483 void mem_cgroup_print_oom_context(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1488 pr_cont(",oom_memcg=");
1489 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1491 pr_cont(",global_oom");
1493 pr_cont(",task_memcg=");
1494 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1500 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1501 * memory controller.
1502 * @memcg: The memory cgroup that went over limit
1504 void mem_cgroup_print_oom_meminfo(struct mem_cgroup
*memcg
)
1508 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1509 K((u64
)page_counter_read(&memcg
->memory
)),
1510 K((u64
)READ_ONCE(memcg
->memory
.max
)), memcg
->memory
.failcnt
);
1511 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1512 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1513 K((u64
)page_counter_read(&memcg
->swap
)),
1514 K((u64
)READ_ONCE(memcg
->swap
.max
)), memcg
->swap
.failcnt
);
1516 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1517 K((u64
)page_counter_read(&memcg
->memsw
)),
1518 K((u64
)memcg
->memsw
.max
), memcg
->memsw
.failcnt
);
1519 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1520 K((u64
)page_counter_read(&memcg
->kmem
)),
1521 K((u64
)memcg
->kmem
.max
), memcg
->kmem
.failcnt
);
1524 pr_info("Memory cgroup stats for ");
1525 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1527 buf
= memory_stat_format(memcg
);
1535 * Return the memory (and swap, if configured) limit for a memcg.
1537 unsigned long mem_cgroup_get_max(struct mem_cgroup
*memcg
)
1539 unsigned long max
= READ_ONCE(memcg
->memory
.max
);
1541 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
1542 if (mem_cgroup_swappiness(memcg
))
1543 max
+= min(READ_ONCE(memcg
->swap
.max
),
1544 (unsigned long)total_swap_pages
);
1546 if (mem_cgroup_swappiness(memcg
)) {
1547 /* Calculate swap excess capacity from memsw limit */
1548 unsigned long swap
= READ_ONCE(memcg
->memsw
.max
) - max
;
1550 max
+= min(swap
, (unsigned long)total_swap_pages
);
1556 unsigned long mem_cgroup_size(struct mem_cgroup
*memcg
)
1558 return page_counter_read(&memcg
->memory
);
1561 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1564 struct oom_control oc
= {
1568 .gfp_mask
= gfp_mask
,
1573 if (mutex_lock_killable(&oom_lock
))
1576 if (mem_cgroup_margin(memcg
) >= (1 << order
))
1580 * A few threads which were not waiting at mutex_lock_killable() can
1581 * fail to bail out. Therefore, check again after holding oom_lock.
1583 ret
= should_force_charge() || out_of_memory(&oc
);
1586 mutex_unlock(&oom_lock
);
1590 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1593 unsigned long *total_scanned
)
1595 struct mem_cgroup
*victim
= NULL
;
1598 unsigned long excess
;
1599 unsigned long nr_scanned
;
1600 struct mem_cgroup_reclaim_cookie reclaim
= {
1604 excess
= soft_limit_excess(root_memcg
);
1607 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1612 * If we have not been able to reclaim
1613 * anything, it might because there are
1614 * no reclaimable pages under this hierarchy
1619 * We want to do more targeted reclaim.
1620 * excess >> 2 is not to excessive so as to
1621 * reclaim too much, nor too less that we keep
1622 * coming back to reclaim from this cgroup
1624 if (total
>= (excess
>> 2) ||
1625 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1630 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1631 pgdat
, &nr_scanned
);
1632 *total_scanned
+= nr_scanned
;
1633 if (!soft_limit_excess(root_memcg
))
1636 mem_cgroup_iter_break(root_memcg
, victim
);
1640 #ifdef CONFIG_LOCKDEP
1641 static struct lockdep_map memcg_oom_lock_dep_map
= {
1642 .name
= "memcg_oom_lock",
1646 static DEFINE_SPINLOCK(memcg_oom_lock
);
1649 * Check OOM-Killer is already running under our hierarchy.
1650 * If someone is running, return false.
1652 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1654 struct mem_cgroup
*iter
, *failed
= NULL
;
1656 spin_lock(&memcg_oom_lock
);
1658 for_each_mem_cgroup_tree(iter
, memcg
) {
1659 if (iter
->oom_lock
) {
1661 * this subtree of our hierarchy is already locked
1662 * so we cannot give a lock.
1665 mem_cgroup_iter_break(memcg
, iter
);
1668 iter
->oom_lock
= true;
1673 * OK, we failed to lock the whole subtree so we have
1674 * to clean up what we set up to the failing subtree
1676 for_each_mem_cgroup_tree(iter
, memcg
) {
1677 if (iter
== failed
) {
1678 mem_cgroup_iter_break(memcg
, iter
);
1681 iter
->oom_lock
= false;
1684 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1686 spin_unlock(&memcg_oom_lock
);
1691 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1693 struct mem_cgroup
*iter
;
1695 spin_lock(&memcg_oom_lock
);
1696 mutex_release(&memcg_oom_lock_dep_map
, _RET_IP_
);
1697 for_each_mem_cgroup_tree(iter
, memcg
)
1698 iter
->oom_lock
= false;
1699 spin_unlock(&memcg_oom_lock
);
1702 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1704 struct mem_cgroup
*iter
;
1706 spin_lock(&memcg_oom_lock
);
1707 for_each_mem_cgroup_tree(iter
, memcg
)
1709 spin_unlock(&memcg_oom_lock
);
1712 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1714 struct mem_cgroup
*iter
;
1717 * Be careful about under_oom underflows because a child memcg
1718 * could have been added after mem_cgroup_mark_under_oom.
1720 spin_lock(&memcg_oom_lock
);
1721 for_each_mem_cgroup_tree(iter
, memcg
)
1722 if (iter
->under_oom
> 0)
1724 spin_unlock(&memcg_oom_lock
);
1727 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1729 struct oom_wait_info
{
1730 struct mem_cgroup
*memcg
;
1731 wait_queue_entry_t wait
;
1734 static int memcg_oom_wake_function(wait_queue_entry_t
*wait
,
1735 unsigned mode
, int sync
, void *arg
)
1737 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1738 struct mem_cgroup
*oom_wait_memcg
;
1739 struct oom_wait_info
*oom_wait_info
;
1741 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1742 oom_wait_memcg
= oom_wait_info
->memcg
;
1744 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1745 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1747 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1750 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1753 * For the following lockless ->under_oom test, the only required
1754 * guarantee is that it must see the state asserted by an OOM when
1755 * this function is called as a result of userland actions
1756 * triggered by the notification of the OOM. This is trivially
1757 * achieved by invoking mem_cgroup_mark_under_oom() before
1758 * triggering notification.
1760 if (memcg
&& memcg
->under_oom
)
1761 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1771 static enum oom_status
mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1773 enum oom_status ret
;
1776 if (order
> PAGE_ALLOC_COSTLY_ORDER
)
1779 memcg_memory_event(memcg
, MEMCG_OOM
);
1782 * We are in the middle of the charge context here, so we
1783 * don't want to block when potentially sitting on a callstack
1784 * that holds all kinds of filesystem and mm locks.
1786 * cgroup1 allows disabling the OOM killer and waiting for outside
1787 * handling until the charge can succeed; remember the context and put
1788 * the task to sleep at the end of the page fault when all locks are
1791 * On the other hand, in-kernel OOM killer allows for an async victim
1792 * memory reclaim (oom_reaper) and that means that we are not solely
1793 * relying on the oom victim to make a forward progress and we can
1794 * invoke the oom killer here.
1796 * Please note that mem_cgroup_out_of_memory might fail to find a
1797 * victim and then we have to bail out from the charge path.
1799 if (memcg
->oom_kill_disable
) {
1800 if (!current
->in_user_fault
)
1802 css_get(&memcg
->css
);
1803 current
->memcg_in_oom
= memcg
;
1804 current
->memcg_oom_gfp_mask
= mask
;
1805 current
->memcg_oom_order
= order
;
1810 mem_cgroup_mark_under_oom(memcg
);
1812 locked
= mem_cgroup_oom_trylock(memcg
);
1815 mem_cgroup_oom_notify(memcg
);
1817 mem_cgroup_unmark_under_oom(memcg
);
1818 if (mem_cgroup_out_of_memory(memcg
, mask
, order
))
1824 mem_cgroup_oom_unlock(memcg
);
1830 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1831 * @handle: actually kill/wait or just clean up the OOM state
1833 * This has to be called at the end of a page fault if the memcg OOM
1834 * handler was enabled.
1836 * Memcg supports userspace OOM handling where failed allocations must
1837 * sleep on a waitqueue until the userspace task resolves the
1838 * situation. Sleeping directly in the charge context with all kinds
1839 * of locks held is not a good idea, instead we remember an OOM state
1840 * in the task and mem_cgroup_oom_synchronize() has to be called at
1841 * the end of the page fault to complete the OOM handling.
1843 * Returns %true if an ongoing memcg OOM situation was detected and
1844 * completed, %false otherwise.
1846 bool mem_cgroup_oom_synchronize(bool handle
)
1848 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1849 struct oom_wait_info owait
;
1852 /* OOM is global, do not handle */
1859 owait
.memcg
= memcg
;
1860 owait
.wait
.flags
= 0;
1861 owait
.wait
.func
= memcg_oom_wake_function
;
1862 owait
.wait
.private = current
;
1863 INIT_LIST_HEAD(&owait
.wait
.entry
);
1865 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1866 mem_cgroup_mark_under_oom(memcg
);
1868 locked
= mem_cgroup_oom_trylock(memcg
);
1871 mem_cgroup_oom_notify(memcg
);
1873 if (locked
&& !memcg
->oom_kill_disable
) {
1874 mem_cgroup_unmark_under_oom(memcg
);
1875 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1876 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1877 current
->memcg_oom_order
);
1880 mem_cgroup_unmark_under_oom(memcg
);
1881 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1885 mem_cgroup_oom_unlock(memcg
);
1887 * There is no guarantee that an OOM-lock contender
1888 * sees the wakeups triggered by the OOM kill
1889 * uncharges. Wake any sleepers explicitly.
1891 memcg_oom_recover(memcg
);
1894 current
->memcg_in_oom
= NULL
;
1895 css_put(&memcg
->css
);
1900 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1901 * @victim: task to be killed by the OOM killer
1902 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1904 * Returns a pointer to a memory cgroup, which has to be cleaned up
1905 * by killing all belonging OOM-killable tasks.
1907 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1909 struct mem_cgroup
*mem_cgroup_get_oom_group(struct task_struct
*victim
,
1910 struct mem_cgroup
*oom_domain
)
1912 struct mem_cgroup
*oom_group
= NULL
;
1913 struct mem_cgroup
*memcg
;
1915 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1919 oom_domain
= root_mem_cgroup
;
1923 memcg
= mem_cgroup_from_task(victim
);
1924 if (memcg
== root_mem_cgroup
)
1928 * If the victim task has been asynchronously moved to a different
1929 * memory cgroup, we might end up killing tasks outside oom_domain.
1930 * In this case it's better to ignore memory.group.oom.
1932 if (unlikely(!mem_cgroup_is_descendant(memcg
, oom_domain
)))
1936 * Traverse the memory cgroup hierarchy from the victim task's
1937 * cgroup up to the OOMing cgroup (or root) to find the
1938 * highest-level memory cgroup with oom.group set.
1940 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
1941 if (memcg
->oom_group
)
1944 if (memcg
== oom_domain
)
1949 css_get(&oom_group
->css
);
1956 void mem_cgroup_print_oom_group(struct mem_cgroup
*memcg
)
1958 pr_info("Tasks in ");
1959 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1960 pr_cont(" are going to be killed due to memory.oom.group set\n");
1964 * lock_page_memcg - lock a page and memcg binding
1967 * This function protects unlocked LRU pages from being moved to
1970 * It ensures lifetime of the locked memcg. Caller is responsible
1971 * for the lifetime of the page.
1973 void lock_page_memcg(struct page
*page
)
1975 struct page
*head
= compound_head(page
); /* rmap on tail pages */
1976 struct mem_cgroup
*memcg
;
1977 unsigned long flags
;
1980 * The RCU lock is held throughout the transaction. The fast
1981 * path can get away without acquiring the memcg->move_lock
1982 * because page moving starts with an RCU grace period.
1986 if (mem_cgroup_disabled())
1989 memcg
= page_memcg(head
);
1990 if (unlikely(!memcg
))
1993 #ifdef CONFIG_PROVE_LOCKING
1994 local_irq_save(flags
);
1995 might_lock(&memcg
->move_lock
);
1996 local_irq_restore(flags
);
1999 if (atomic_read(&memcg
->moving_account
) <= 0)
2002 spin_lock_irqsave(&memcg
->move_lock
, flags
);
2003 if (memcg
!= page_memcg(head
)) {
2004 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2009 * When charge migration first begins, we can have multiple
2010 * critical sections holding the fast-path RCU lock and one
2011 * holding the slowpath move_lock. Track the task who has the
2012 * move_lock for unlock_page_memcg().
2014 memcg
->move_lock_task
= current
;
2015 memcg
->move_lock_flags
= flags
;
2017 EXPORT_SYMBOL(lock_page_memcg
);
2019 static void __unlock_page_memcg(struct mem_cgroup
*memcg
)
2021 if (memcg
&& memcg
->move_lock_task
== current
) {
2022 unsigned long flags
= memcg
->move_lock_flags
;
2024 memcg
->move_lock_task
= NULL
;
2025 memcg
->move_lock_flags
= 0;
2027 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2034 * unlock_page_memcg - unlock a page and memcg binding
2037 void unlock_page_memcg(struct page
*page
)
2039 struct page
*head
= compound_head(page
);
2041 __unlock_page_memcg(page_memcg(head
));
2043 EXPORT_SYMBOL(unlock_page_memcg
);
2046 #ifdef CONFIG_MEMCG_KMEM
2047 struct obj_cgroup
*cached_objcg
;
2048 struct pglist_data
*cached_pgdat
;
2049 unsigned int nr_bytes
;
2050 int nr_slab_reclaimable_b
;
2051 int nr_slab_unreclaimable_b
;
2057 struct memcg_stock_pcp
{
2058 struct mem_cgroup
*cached
; /* this never be root cgroup */
2059 unsigned int nr_pages
;
2060 struct obj_stock task_obj
;
2061 struct obj_stock irq_obj
;
2063 struct work_struct work
;
2064 unsigned long flags
;
2065 #define FLUSHING_CACHED_CHARGE 0
2067 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2068 static DEFINE_MUTEX(percpu_charge_mutex
);
2070 #ifdef CONFIG_MEMCG_KMEM
2071 static void drain_obj_stock(struct obj_stock
*stock
);
2072 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
2073 struct mem_cgroup
*root_memcg
);
2076 static inline void drain_obj_stock(struct obj_stock
*stock
)
2079 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
2080 struct mem_cgroup
*root_memcg
)
2087 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
2088 * sequence used in this case to access content from object stock is slow.
2089 * To optimize for user context access, there are now two object stocks for
2090 * task context and interrupt context access respectively.
2092 * The task context object stock can be accessed by disabling preemption only
2093 * which is cheap in non-preempt kernel. The interrupt context object stock
2094 * can only be accessed after disabling interrupt. User context code can
2095 * access interrupt object stock, but not vice versa.
2097 static inline struct obj_stock
*get_obj_stock(unsigned long *pflags
)
2099 struct memcg_stock_pcp
*stock
;
2101 if (likely(in_task())) {
2104 stock
= this_cpu_ptr(&memcg_stock
);
2105 return &stock
->task_obj
;
2108 local_irq_save(*pflags
);
2109 stock
= this_cpu_ptr(&memcg_stock
);
2110 return &stock
->irq_obj
;
2113 static inline void put_obj_stock(unsigned long flags
)
2115 if (likely(in_task()))
2118 local_irq_restore(flags
);
2122 * consume_stock: Try to consume stocked charge on this cpu.
2123 * @memcg: memcg to consume from.
2124 * @nr_pages: how many pages to charge.
2126 * The charges will only happen if @memcg matches the current cpu's memcg
2127 * stock, and at least @nr_pages are available in that stock. Failure to
2128 * service an allocation will refill the stock.
2130 * returns true if successful, false otherwise.
2132 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2134 struct memcg_stock_pcp
*stock
;
2135 unsigned long flags
;
2138 if (nr_pages
> MEMCG_CHARGE_BATCH
)
2141 local_irq_save(flags
);
2143 stock
= this_cpu_ptr(&memcg_stock
);
2144 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
2145 stock
->nr_pages
-= nr_pages
;
2149 local_irq_restore(flags
);
2155 * Returns stocks cached in percpu and reset cached information.
2157 static void drain_stock(struct memcg_stock_pcp
*stock
)
2159 struct mem_cgroup
*old
= stock
->cached
;
2164 if (stock
->nr_pages
) {
2165 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
2166 if (do_memsw_account())
2167 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
2168 stock
->nr_pages
= 0;
2172 stock
->cached
= NULL
;
2175 static void drain_local_stock(struct work_struct
*dummy
)
2177 struct memcg_stock_pcp
*stock
;
2178 unsigned long flags
;
2181 * The only protection from cpu hotplug (memcg_hotplug_cpu_dead) vs.
2182 * drain_stock races is that we always operate on local CPU stock
2183 * here with IRQ disabled
2185 local_irq_save(flags
);
2187 stock
= this_cpu_ptr(&memcg_stock
);
2188 drain_obj_stock(&stock
->irq_obj
);
2190 drain_obj_stock(&stock
->task_obj
);
2192 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2194 local_irq_restore(flags
);
2198 * Cache charges(val) to local per_cpu area.
2199 * This will be consumed by consume_stock() function, later.
2201 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2203 struct memcg_stock_pcp
*stock
;
2204 unsigned long flags
;
2206 local_irq_save(flags
);
2208 stock
= this_cpu_ptr(&memcg_stock
);
2209 if (stock
->cached
!= memcg
) { /* reset if necessary */
2211 css_get(&memcg
->css
);
2212 stock
->cached
= memcg
;
2214 stock
->nr_pages
+= nr_pages
;
2216 if (stock
->nr_pages
> MEMCG_CHARGE_BATCH
)
2219 local_irq_restore(flags
);
2223 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2224 * of the hierarchy under it.
2226 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
2230 /* If someone's already draining, avoid adding running more workers. */
2231 if (!mutex_trylock(&percpu_charge_mutex
))
2234 * Notify other cpus that system-wide "drain" is running
2235 * We do not care about races with the cpu hotplug because cpu down
2236 * as well as workers from this path always operate on the local
2237 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2240 for_each_online_cpu(cpu
) {
2241 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2242 struct mem_cgroup
*memcg
;
2246 memcg
= stock
->cached
;
2247 if (memcg
&& stock
->nr_pages
&&
2248 mem_cgroup_is_descendant(memcg
, root_memcg
))
2250 else if (obj_stock_flush_required(stock
, root_memcg
))
2255 !test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2257 drain_local_stock(&stock
->work
);
2259 schedule_work_on(cpu
, &stock
->work
);
2263 mutex_unlock(&percpu_charge_mutex
);
2266 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
2268 struct memcg_stock_pcp
*stock
;
2270 stock
= &per_cpu(memcg_stock
, cpu
);
2276 static unsigned long reclaim_high(struct mem_cgroup
*memcg
,
2277 unsigned int nr_pages
,
2280 unsigned long nr_reclaimed
= 0;
2283 unsigned long pflags
;
2285 if (page_counter_read(&memcg
->memory
) <=
2286 READ_ONCE(memcg
->memory
.high
))
2289 memcg_memory_event(memcg
, MEMCG_HIGH
);
2291 psi_memstall_enter(&pflags
);
2292 nr_reclaimed
+= try_to_free_mem_cgroup_pages(memcg
, nr_pages
,
2294 psi_memstall_leave(&pflags
);
2295 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2296 !mem_cgroup_is_root(memcg
));
2298 return nr_reclaimed
;
2301 static void high_work_func(struct work_struct
*work
)
2303 struct mem_cgroup
*memcg
;
2305 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
2306 reclaim_high(memcg
, MEMCG_CHARGE_BATCH
, GFP_KERNEL
);
2310 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2311 * enough to still cause a significant slowdown in most cases, while still
2312 * allowing diagnostics and tracing to proceed without becoming stuck.
2314 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2317 * When calculating the delay, we use these either side of the exponentiation to
2318 * maintain precision and scale to a reasonable number of jiffies (see the table
2321 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2322 * overage ratio to a delay.
2323 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
2324 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2325 * to produce a reasonable delay curve.
2327 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2328 * reasonable delay curve compared to precision-adjusted overage, not
2329 * penalising heavily at first, but still making sure that growth beyond the
2330 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2331 * example, with a high of 100 megabytes:
2333 * +-------+------------------------+
2334 * | usage | time to allocate in ms |
2335 * +-------+------------------------+
2357 * +-------+------------------------+
2359 #define MEMCG_DELAY_PRECISION_SHIFT 20
2360 #define MEMCG_DELAY_SCALING_SHIFT 14
2362 static u64
calculate_overage(unsigned long usage
, unsigned long high
)
2370 * Prevent division by 0 in overage calculation by acting as if
2371 * it was a threshold of 1 page
2373 high
= max(high
, 1UL);
2375 overage
= usage
- high
;
2376 overage
<<= MEMCG_DELAY_PRECISION_SHIFT
;
2377 return div64_u64(overage
, high
);
2380 static u64
mem_find_max_overage(struct mem_cgroup
*memcg
)
2382 u64 overage
, max_overage
= 0;
2385 overage
= calculate_overage(page_counter_read(&memcg
->memory
),
2386 READ_ONCE(memcg
->memory
.high
));
2387 max_overage
= max(overage
, max_overage
);
2388 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2389 !mem_cgroup_is_root(memcg
));
2394 static u64
swap_find_max_overage(struct mem_cgroup
*memcg
)
2396 u64 overage
, max_overage
= 0;
2399 overage
= calculate_overage(page_counter_read(&memcg
->swap
),
2400 READ_ONCE(memcg
->swap
.high
));
2402 memcg_memory_event(memcg
, MEMCG_SWAP_HIGH
);
2403 max_overage
= max(overage
, max_overage
);
2404 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2405 !mem_cgroup_is_root(memcg
));
2411 * Get the number of jiffies that we should penalise a mischievous cgroup which
2412 * is exceeding its memory.high by checking both it and its ancestors.
2414 static unsigned long calculate_high_delay(struct mem_cgroup
*memcg
,
2415 unsigned int nr_pages
,
2418 unsigned long penalty_jiffies
;
2424 * We use overage compared to memory.high to calculate the number of
2425 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2426 * fairly lenient on small overages, and increasingly harsh when the
2427 * memcg in question makes it clear that it has no intention of stopping
2428 * its crazy behaviour, so we exponentially increase the delay based on
2431 penalty_jiffies
= max_overage
* max_overage
* HZ
;
2432 penalty_jiffies
>>= MEMCG_DELAY_PRECISION_SHIFT
;
2433 penalty_jiffies
>>= MEMCG_DELAY_SCALING_SHIFT
;
2436 * Factor in the task's own contribution to the overage, such that four
2437 * N-sized allocations are throttled approximately the same as one
2438 * 4N-sized allocation.
2440 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2441 * larger the current charge patch is than that.
2443 return penalty_jiffies
* nr_pages
/ MEMCG_CHARGE_BATCH
;
2447 * Scheduled by try_charge() to be executed from the userland return path
2448 * and reclaims memory over the high limit.
2450 void mem_cgroup_handle_over_high(void)
2452 unsigned long penalty_jiffies
;
2453 unsigned long pflags
;
2454 unsigned long nr_reclaimed
;
2455 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
2456 int nr_retries
= MAX_RECLAIM_RETRIES
;
2457 struct mem_cgroup
*memcg
;
2458 bool in_retry
= false;
2460 if (likely(!nr_pages
))
2463 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2464 current
->memcg_nr_pages_over_high
= 0;
2468 * The allocating task should reclaim at least the batch size, but for
2469 * subsequent retries we only want to do what's necessary to prevent oom
2470 * or breaching resource isolation.
2472 * This is distinct from memory.max or page allocator behaviour because
2473 * memory.high is currently batched, whereas memory.max and the page
2474 * allocator run every time an allocation is made.
2476 nr_reclaimed
= reclaim_high(memcg
,
2477 in_retry
? SWAP_CLUSTER_MAX
: nr_pages
,
2481 * memory.high is breached and reclaim is unable to keep up. Throttle
2482 * allocators proactively to slow down excessive growth.
2484 penalty_jiffies
= calculate_high_delay(memcg
, nr_pages
,
2485 mem_find_max_overage(memcg
));
2487 penalty_jiffies
+= calculate_high_delay(memcg
, nr_pages
,
2488 swap_find_max_overage(memcg
));
2491 * Clamp the max delay per usermode return so as to still keep the
2492 * application moving forwards and also permit diagnostics, albeit
2495 penalty_jiffies
= min(penalty_jiffies
, MEMCG_MAX_HIGH_DELAY_JIFFIES
);
2498 * Don't sleep if the amount of jiffies this memcg owes us is so low
2499 * that it's not even worth doing, in an attempt to be nice to those who
2500 * go only a small amount over their memory.high value and maybe haven't
2501 * been aggressively reclaimed enough yet.
2503 if (penalty_jiffies
<= HZ
/ 100)
2507 * If reclaim is making forward progress but we're still over
2508 * memory.high, we want to encourage that rather than doing allocator
2511 if (nr_reclaimed
|| nr_retries
--) {
2517 * If we exit early, we're guaranteed to die (since
2518 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2519 * need to account for any ill-begotten jiffies to pay them off later.
2521 psi_memstall_enter(&pflags
);
2522 schedule_timeout_killable(penalty_jiffies
);
2523 psi_memstall_leave(&pflags
);
2526 css_put(&memcg
->css
);
2529 static int try_charge_memcg(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2530 unsigned int nr_pages
)
2532 unsigned int batch
= max(MEMCG_CHARGE_BATCH
, nr_pages
);
2533 int nr_retries
= MAX_RECLAIM_RETRIES
;
2534 struct mem_cgroup
*mem_over_limit
;
2535 struct page_counter
*counter
;
2536 enum oom_status oom_status
;
2537 unsigned long nr_reclaimed
;
2538 bool may_swap
= true;
2539 bool drained
= false;
2540 unsigned long pflags
;
2543 if (consume_stock(memcg
, nr_pages
))
2546 if (!do_memsw_account() ||
2547 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
2548 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
2550 if (do_memsw_account())
2551 page_counter_uncharge(&memcg
->memsw
, batch
);
2552 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
2554 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
2558 if (batch
> nr_pages
) {
2564 * Memcg doesn't have a dedicated reserve for atomic
2565 * allocations. But like the global atomic pool, we need to
2566 * put the burden of reclaim on regular allocation requests
2567 * and let these go through as privileged allocations.
2569 if (gfp_mask
& __GFP_ATOMIC
)
2573 * Unlike in global OOM situations, memcg is not in a physical
2574 * memory shortage. Allow dying and OOM-killed tasks to
2575 * bypass the last charges so that they can exit quickly and
2576 * free their memory.
2578 if (unlikely(should_force_charge()))
2582 * Prevent unbounded recursion when reclaim operations need to
2583 * allocate memory. This might exceed the limits temporarily,
2584 * but we prefer facilitating memory reclaim and getting back
2585 * under the limit over triggering OOM kills in these cases.
2587 if (unlikely(current
->flags
& PF_MEMALLOC
))
2590 if (unlikely(task_in_memcg_oom(current
)))
2593 if (!gfpflags_allow_blocking(gfp_mask
))
2596 memcg_memory_event(mem_over_limit
, MEMCG_MAX
);
2598 psi_memstall_enter(&pflags
);
2599 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
2600 gfp_mask
, may_swap
);
2601 psi_memstall_leave(&pflags
);
2603 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2607 drain_all_stock(mem_over_limit
);
2612 if (gfp_mask
& __GFP_NORETRY
)
2615 * Even though the limit is exceeded at this point, reclaim
2616 * may have been able to free some pages. Retry the charge
2617 * before killing the task.
2619 * Only for regular pages, though: huge pages are rather
2620 * unlikely to succeed so close to the limit, and we fall back
2621 * to regular pages anyway in case of failure.
2623 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
2626 * At task move, charge accounts can be doubly counted. So, it's
2627 * better to wait until the end of task_move if something is going on.
2629 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2635 if (gfp_mask
& __GFP_RETRY_MAYFAIL
)
2638 if (fatal_signal_pending(current
))
2642 * keep retrying as long as the memcg oom killer is able to make
2643 * a forward progress or bypass the charge if the oom killer
2644 * couldn't make any progress.
2646 oom_status
= mem_cgroup_oom(mem_over_limit
, gfp_mask
,
2647 get_order(nr_pages
* PAGE_SIZE
));
2648 switch (oom_status
) {
2650 nr_retries
= MAX_RECLAIM_RETRIES
;
2658 if (!(gfp_mask
& __GFP_NOFAIL
))
2662 * The allocation either can't fail or will lead to more memory
2663 * being freed very soon. Allow memory usage go over the limit
2664 * temporarily by force charging it.
2666 page_counter_charge(&memcg
->memory
, nr_pages
);
2667 if (do_memsw_account())
2668 page_counter_charge(&memcg
->memsw
, nr_pages
);
2673 if (batch
> nr_pages
)
2674 refill_stock(memcg
, batch
- nr_pages
);
2677 * If the hierarchy is above the normal consumption range, schedule
2678 * reclaim on returning to userland. We can perform reclaim here
2679 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2680 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2681 * not recorded as it most likely matches current's and won't
2682 * change in the meantime. As high limit is checked again before
2683 * reclaim, the cost of mismatch is negligible.
2686 bool mem_high
, swap_high
;
2688 mem_high
= page_counter_read(&memcg
->memory
) >
2689 READ_ONCE(memcg
->memory
.high
);
2690 swap_high
= page_counter_read(&memcg
->swap
) >
2691 READ_ONCE(memcg
->swap
.high
);
2693 /* Don't bother a random interrupted task */
2694 if (in_interrupt()) {
2696 schedule_work(&memcg
->high_work
);
2702 if (mem_high
|| swap_high
) {
2704 * The allocating tasks in this cgroup will need to do
2705 * reclaim or be throttled to prevent further growth
2706 * of the memory or swap footprints.
2708 * Target some best-effort fairness between the tasks,
2709 * and distribute reclaim work and delay penalties
2710 * based on how much each task is actually allocating.
2712 current
->memcg_nr_pages_over_high
+= batch
;
2713 set_notify_resume(current
);
2716 } while ((memcg
= parent_mem_cgroup(memcg
)));
2721 static inline int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2722 unsigned int nr_pages
)
2724 if (mem_cgroup_is_root(memcg
))
2727 return try_charge_memcg(memcg
, gfp_mask
, nr_pages
);
2730 #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
2731 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2733 if (mem_cgroup_is_root(memcg
))
2736 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2737 if (do_memsw_account())
2738 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2742 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
)
2744 VM_BUG_ON_PAGE(page_memcg(page
), page
);
2746 * Any of the following ensures page's memcg stability:
2750 * - lock_page_memcg()
2751 * - exclusive reference
2753 page
->memcg_data
= (unsigned long)memcg
;
2756 static struct mem_cgroup
*get_mem_cgroup_from_objcg(struct obj_cgroup
*objcg
)
2758 struct mem_cgroup
*memcg
;
2762 memcg
= obj_cgroup_memcg(objcg
);
2763 if (unlikely(!css_tryget(&memcg
->css
)))
2770 #ifdef CONFIG_MEMCG_KMEM
2772 * The allocated objcg pointers array is not accounted directly.
2773 * Moreover, it should not come from DMA buffer and is not readily
2774 * reclaimable. So those GFP bits should be masked off.
2776 #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
2778 int memcg_alloc_page_obj_cgroups(struct page
*page
, struct kmem_cache
*s
,
2779 gfp_t gfp
, bool new_page
)
2781 unsigned int objects
= objs_per_slab_page(s
, page
);
2782 unsigned long memcg_data
;
2785 gfp
&= ~OBJCGS_CLEAR_MASK
;
2786 vec
= kcalloc_node(objects
, sizeof(struct obj_cgroup
*), gfp
,
2791 memcg_data
= (unsigned long) vec
| MEMCG_DATA_OBJCGS
;
2794 * If the slab page is brand new and nobody can yet access
2795 * it's memcg_data, no synchronization is required and
2796 * memcg_data can be simply assigned.
2798 page
->memcg_data
= memcg_data
;
2799 } else if (cmpxchg(&page
->memcg_data
, 0, memcg_data
)) {
2801 * If the slab page is already in use, somebody can allocate
2802 * and assign obj_cgroups in parallel. In this case the existing
2803 * objcg vector should be reused.
2809 kmemleak_not_leak(vec
);
2814 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2816 * A passed kernel object can be a slab object or a generic kernel page, so
2817 * different mechanisms for getting the memory cgroup pointer should be used.
2818 * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
2819 * can not know for sure how the kernel object is implemented.
2820 * mem_cgroup_from_obj() can be safely used in such cases.
2822 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2823 * cgroup_mutex, etc.
2825 struct mem_cgroup
*mem_cgroup_from_obj(void *p
)
2829 if (mem_cgroup_disabled())
2832 page
= virt_to_head_page(p
);
2835 * Slab objects are accounted individually, not per-page.
2836 * Memcg membership data for each individual object is saved in
2837 * the page->obj_cgroups.
2839 if (page_objcgs_check(page
)) {
2840 struct obj_cgroup
*objcg
;
2843 off
= obj_to_index(page
->slab_cache
, page
, p
);
2844 objcg
= page_objcgs(page
)[off
];
2846 return obj_cgroup_memcg(objcg
);
2852 * page_memcg_check() is used here, because page_has_obj_cgroups()
2853 * check above could fail because the object cgroups vector wasn't set
2854 * at that moment, but it can be set concurrently.
2855 * page_memcg_check(page) will guarantee that a proper memory
2856 * cgroup pointer or NULL will be returned.
2858 return page_memcg_check(page
);
2861 __always_inline
struct obj_cgroup
*get_obj_cgroup_from_current(void)
2863 struct obj_cgroup
*objcg
= NULL
;
2864 struct mem_cgroup
*memcg
;
2866 if (memcg_kmem_bypass())
2870 if (unlikely(active_memcg()))
2871 memcg
= active_memcg();
2873 memcg
= mem_cgroup_from_task(current
);
2875 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
)) {
2876 objcg
= rcu_dereference(memcg
->objcg
);
2877 if (objcg
&& obj_cgroup_tryget(objcg
))
2886 static int memcg_alloc_cache_id(void)
2891 id
= ida_simple_get(&memcg_cache_ida
,
2892 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2896 if (id
< memcg_nr_cache_ids
)
2900 * There's no space for the new id in memcg_caches arrays,
2901 * so we have to grow them.
2903 down_write(&memcg_cache_ids_sem
);
2905 size
= 2 * (id
+ 1);
2906 if (size
< MEMCG_CACHES_MIN_SIZE
)
2907 size
= MEMCG_CACHES_MIN_SIZE
;
2908 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2909 size
= MEMCG_CACHES_MAX_SIZE
;
2911 err
= memcg_update_all_list_lrus(size
);
2913 memcg_nr_cache_ids
= size
;
2915 up_write(&memcg_cache_ids_sem
);
2918 ida_simple_remove(&memcg_cache_ida
, id
);
2924 static void memcg_free_cache_id(int id
)
2926 ida_simple_remove(&memcg_cache_ida
, id
);
2930 * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
2931 * @objcg: object cgroup to uncharge
2932 * @nr_pages: number of pages to uncharge
2934 static void obj_cgroup_uncharge_pages(struct obj_cgroup
*objcg
,
2935 unsigned int nr_pages
)
2937 struct mem_cgroup
*memcg
;
2939 memcg
= get_mem_cgroup_from_objcg(objcg
);
2941 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2942 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2943 refill_stock(memcg
, nr_pages
);
2945 css_put(&memcg
->css
);
2949 * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
2950 * @objcg: object cgroup to charge
2951 * @gfp: reclaim mode
2952 * @nr_pages: number of pages to charge
2954 * Returns 0 on success, an error code on failure.
2956 static int obj_cgroup_charge_pages(struct obj_cgroup
*objcg
, gfp_t gfp
,
2957 unsigned int nr_pages
)
2959 struct page_counter
*counter
;
2960 struct mem_cgroup
*memcg
;
2963 memcg
= get_mem_cgroup_from_objcg(objcg
);
2965 ret
= try_charge_memcg(memcg
, gfp
, nr_pages
);
2969 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
2970 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
2973 * Enforce __GFP_NOFAIL allocation because callers are not
2974 * prepared to see failures and likely do not have any failure
2977 if (gfp
& __GFP_NOFAIL
) {
2978 page_counter_charge(&memcg
->kmem
, nr_pages
);
2981 cancel_charge(memcg
, nr_pages
);
2985 css_put(&memcg
->css
);
2991 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
2992 * @page: page to charge
2993 * @gfp: reclaim mode
2994 * @order: allocation order
2996 * Returns 0 on success, an error code on failure.
2998 int __memcg_kmem_charge_page(struct page
*page
, gfp_t gfp
, int order
)
3000 struct obj_cgroup
*objcg
;
3003 objcg
= get_obj_cgroup_from_current();
3005 ret
= obj_cgroup_charge_pages(objcg
, gfp
, 1 << order
);
3007 page
->memcg_data
= (unsigned long)objcg
|
3011 obj_cgroup_put(objcg
);
3017 * __memcg_kmem_uncharge_page: uncharge a kmem page
3018 * @page: page to uncharge
3019 * @order: allocation order
3021 void __memcg_kmem_uncharge_page(struct page
*page
, int order
)
3023 struct obj_cgroup
*objcg
;
3024 unsigned int nr_pages
= 1 << order
;
3026 if (!PageMemcgKmem(page
))
3029 objcg
= __page_objcg(page
);
3030 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
3031 page
->memcg_data
= 0;
3032 obj_cgroup_put(objcg
);
3035 void mod_objcg_state(struct obj_cgroup
*objcg
, struct pglist_data
*pgdat
,
3036 enum node_stat_item idx
, int nr
)
3038 unsigned long flags
;
3039 struct obj_stock
*stock
= get_obj_stock(&flags
);
3043 * Save vmstat data in stock and skip vmstat array update unless
3044 * accumulating over a page of vmstat data or when pgdat or idx
3047 if (stock
->cached_objcg
!= objcg
) {
3048 drain_obj_stock(stock
);
3049 obj_cgroup_get(objcg
);
3050 stock
->nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
)
3051 ? atomic_xchg(&objcg
->nr_charged_bytes
, 0) : 0;
3052 stock
->cached_objcg
= objcg
;
3053 stock
->cached_pgdat
= pgdat
;
3054 } else if (stock
->cached_pgdat
!= pgdat
) {
3055 /* Flush the existing cached vmstat data */
3056 struct pglist_data
*oldpg
= stock
->cached_pgdat
;
3058 if (stock
->nr_slab_reclaimable_b
) {
3059 mod_objcg_mlstate(objcg
, oldpg
, NR_SLAB_RECLAIMABLE_B
,
3060 stock
->nr_slab_reclaimable_b
);
3061 stock
->nr_slab_reclaimable_b
= 0;
3063 if (stock
->nr_slab_unreclaimable_b
) {
3064 mod_objcg_mlstate(objcg
, oldpg
, NR_SLAB_UNRECLAIMABLE_B
,
3065 stock
->nr_slab_unreclaimable_b
);
3066 stock
->nr_slab_unreclaimable_b
= 0;
3068 stock
->cached_pgdat
= pgdat
;
3071 bytes
= (idx
== NR_SLAB_RECLAIMABLE_B
) ? &stock
->nr_slab_reclaimable_b
3072 : &stock
->nr_slab_unreclaimable_b
;
3074 * Even for large object >= PAGE_SIZE, the vmstat data will still be
3075 * cached locally at least once before pushing it out.
3082 if (abs(*bytes
) > PAGE_SIZE
) {
3090 mod_objcg_mlstate(objcg
, pgdat
, idx
, nr
);
3092 put_obj_stock(flags
);
3095 static bool consume_obj_stock(struct obj_cgroup
*objcg
, unsigned int nr_bytes
)
3097 unsigned long flags
;
3098 struct obj_stock
*stock
= get_obj_stock(&flags
);
3101 if (objcg
== stock
->cached_objcg
&& stock
->nr_bytes
>= nr_bytes
) {
3102 stock
->nr_bytes
-= nr_bytes
;
3106 put_obj_stock(flags
);
3111 static void drain_obj_stock(struct obj_stock
*stock
)
3113 struct obj_cgroup
*old
= stock
->cached_objcg
;
3118 if (stock
->nr_bytes
) {
3119 unsigned int nr_pages
= stock
->nr_bytes
>> PAGE_SHIFT
;
3120 unsigned int nr_bytes
= stock
->nr_bytes
& (PAGE_SIZE
- 1);
3123 obj_cgroup_uncharge_pages(old
, nr_pages
);
3126 * The leftover is flushed to the centralized per-memcg value.
3127 * On the next attempt to refill obj stock it will be moved
3128 * to a per-cpu stock (probably, on an other CPU), see
3129 * refill_obj_stock().
3131 * How often it's flushed is a trade-off between the memory
3132 * limit enforcement accuracy and potential CPU contention,
3133 * so it might be changed in the future.
3135 atomic_add(nr_bytes
, &old
->nr_charged_bytes
);
3136 stock
->nr_bytes
= 0;
3140 * Flush the vmstat data in current stock
3142 if (stock
->nr_slab_reclaimable_b
|| stock
->nr_slab_unreclaimable_b
) {
3143 if (stock
->nr_slab_reclaimable_b
) {
3144 mod_objcg_mlstate(old
, stock
->cached_pgdat
,
3145 NR_SLAB_RECLAIMABLE_B
,
3146 stock
->nr_slab_reclaimable_b
);
3147 stock
->nr_slab_reclaimable_b
= 0;
3149 if (stock
->nr_slab_unreclaimable_b
) {
3150 mod_objcg_mlstate(old
, stock
->cached_pgdat
,
3151 NR_SLAB_UNRECLAIMABLE_B
,
3152 stock
->nr_slab_unreclaimable_b
);
3153 stock
->nr_slab_unreclaimable_b
= 0;
3155 stock
->cached_pgdat
= NULL
;
3158 obj_cgroup_put(old
);
3159 stock
->cached_objcg
= NULL
;
3162 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
3163 struct mem_cgroup
*root_memcg
)
3165 struct mem_cgroup
*memcg
;
3167 if (in_task() && stock
->task_obj
.cached_objcg
) {
3168 memcg
= obj_cgroup_memcg(stock
->task_obj
.cached_objcg
);
3169 if (memcg
&& mem_cgroup_is_descendant(memcg
, root_memcg
))
3172 if (stock
->irq_obj
.cached_objcg
) {
3173 memcg
= obj_cgroup_memcg(stock
->irq_obj
.cached_objcg
);
3174 if (memcg
&& mem_cgroup_is_descendant(memcg
, root_memcg
))
3181 static void refill_obj_stock(struct obj_cgroup
*objcg
, unsigned int nr_bytes
,
3182 bool allow_uncharge
)
3184 unsigned long flags
;
3185 struct obj_stock
*stock
= get_obj_stock(&flags
);
3186 unsigned int nr_pages
= 0;
3188 if (stock
->cached_objcg
!= objcg
) { /* reset if necessary */
3189 drain_obj_stock(stock
);
3190 obj_cgroup_get(objcg
);
3191 stock
->cached_objcg
= objcg
;
3192 stock
->nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
)
3193 ? atomic_xchg(&objcg
->nr_charged_bytes
, 0) : 0;
3194 allow_uncharge
= true; /* Allow uncharge when objcg changes */
3196 stock
->nr_bytes
+= nr_bytes
;
3198 if (allow_uncharge
&& (stock
->nr_bytes
> PAGE_SIZE
)) {
3199 nr_pages
= stock
->nr_bytes
>> PAGE_SHIFT
;
3200 stock
->nr_bytes
&= (PAGE_SIZE
- 1);
3203 put_obj_stock(flags
);
3206 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
3209 int obj_cgroup_charge(struct obj_cgroup
*objcg
, gfp_t gfp
, size_t size
)
3211 unsigned int nr_pages
, nr_bytes
;
3214 if (consume_obj_stock(objcg
, size
))
3218 * In theory, objcg->nr_charged_bytes can have enough
3219 * pre-charged bytes to satisfy the allocation. However,
3220 * flushing objcg->nr_charged_bytes requires two atomic
3221 * operations, and objcg->nr_charged_bytes can't be big.
3222 * The shared objcg->nr_charged_bytes can also become a
3223 * performance bottleneck if all tasks of the same memcg are
3224 * trying to update it. So it's better to ignore it and try
3225 * grab some new pages. The stock's nr_bytes will be flushed to
3226 * objcg->nr_charged_bytes later on when objcg changes.
3228 * The stock's nr_bytes may contain enough pre-charged bytes
3229 * to allow one less page from being charged, but we can't rely
3230 * on the pre-charged bytes not being changed outside of
3231 * consume_obj_stock() or refill_obj_stock(). So ignore those
3232 * pre-charged bytes as well when charging pages. To avoid a
3233 * page uncharge right after a page charge, we set the
3234 * allow_uncharge flag to false when calling refill_obj_stock()
3235 * to temporarily allow the pre-charged bytes to exceed the page
3236 * size limit. The maximum reachable value of the pre-charged
3237 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
3240 nr_pages
= size
>> PAGE_SHIFT
;
3241 nr_bytes
= size
& (PAGE_SIZE
- 1);
3246 ret
= obj_cgroup_charge_pages(objcg
, gfp
, nr_pages
);
3247 if (!ret
&& nr_bytes
)
3248 refill_obj_stock(objcg
, PAGE_SIZE
- nr_bytes
, false);
3253 void obj_cgroup_uncharge(struct obj_cgroup
*objcg
, size_t size
)
3255 refill_obj_stock(objcg
, size
, true);
3258 #endif /* CONFIG_MEMCG_KMEM */
3261 * Because page_memcg(head) is not set on tails, set it now.
3263 void split_page_memcg(struct page
*head
, unsigned int nr
)
3265 struct mem_cgroup
*memcg
= page_memcg(head
);
3268 if (mem_cgroup_disabled() || !memcg
)
3271 for (i
= 1; i
< nr
; i
++)
3272 head
[i
].memcg_data
= head
->memcg_data
;
3274 if (PageMemcgKmem(head
))
3275 obj_cgroup_get_many(__page_objcg(head
), nr
- 1);
3277 css_get_many(&memcg
->css
, nr
- 1);
3280 #ifdef CONFIG_MEMCG_SWAP
3282 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3283 * @entry: swap entry to be moved
3284 * @from: mem_cgroup which the entry is moved from
3285 * @to: mem_cgroup which the entry is moved to
3287 * It succeeds only when the swap_cgroup's record for this entry is the same
3288 * as the mem_cgroup's id of @from.
3290 * Returns 0 on success, -EINVAL on failure.
3292 * The caller must have charged to @to, IOW, called page_counter_charge() about
3293 * both res and memsw, and called css_get().
3295 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3296 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3298 unsigned short old_id
, new_id
;
3300 old_id
= mem_cgroup_id(from
);
3301 new_id
= mem_cgroup_id(to
);
3303 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3304 mod_memcg_state(from
, MEMCG_SWAP
, -1);
3305 mod_memcg_state(to
, MEMCG_SWAP
, 1);
3311 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3312 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3318 static DEFINE_MUTEX(memcg_max_mutex
);
3320 static int mem_cgroup_resize_max(struct mem_cgroup
*memcg
,
3321 unsigned long max
, bool memsw
)
3323 bool enlarge
= false;
3324 bool drained
= false;
3326 bool limits_invariant
;
3327 struct page_counter
*counter
= memsw
? &memcg
->memsw
: &memcg
->memory
;
3330 if (signal_pending(current
)) {
3335 mutex_lock(&memcg_max_mutex
);
3337 * Make sure that the new limit (memsw or memory limit) doesn't
3338 * break our basic invariant rule memory.max <= memsw.max.
3340 limits_invariant
= memsw
? max
>= READ_ONCE(memcg
->memory
.max
) :
3341 max
<= memcg
->memsw
.max
;
3342 if (!limits_invariant
) {
3343 mutex_unlock(&memcg_max_mutex
);
3347 if (max
> counter
->max
)
3349 ret
= page_counter_set_max(counter
, max
);
3350 mutex_unlock(&memcg_max_mutex
);
3356 drain_all_stock(memcg
);
3361 if (!try_to_free_mem_cgroup_pages(memcg
, 1,
3362 GFP_KERNEL
, !memsw
)) {
3368 if (!ret
&& enlarge
)
3369 memcg_oom_recover(memcg
);
3374 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
3376 unsigned long *total_scanned
)
3378 unsigned long nr_reclaimed
= 0;
3379 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
3380 unsigned long reclaimed
;
3382 struct mem_cgroup_tree_per_node
*mctz
;
3383 unsigned long excess
;
3384 unsigned long nr_scanned
;
3389 mctz
= soft_limit_tree_node(pgdat
->node_id
);
3392 * Do not even bother to check the largest node if the root
3393 * is empty. Do it lockless to prevent lock bouncing. Races
3394 * are acceptable as soft limit is best effort anyway.
3396 if (!mctz
|| RB_EMPTY_ROOT(&mctz
->rb_root
))
3400 * This loop can run a while, specially if mem_cgroup's continuously
3401 * keep exceeding their soft limit and putting the system under
3408 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3413 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
3414 gfp_mask
, &nr_scanned
);
3415 nr_reclaimed
+= reclaimed
;
3416 *total_scanned
+= nr_scanned
;
3417 spin_lock_irq(&mctz
->lock
);
3418 __mem_cgroup_remove_exceeded(mz
, mctz
);
3421 * If we failed to reclaim anything from this memory cgroup
3422 * it is time to move on to the next cgroup
3426 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
3428 excess
= soft_limit_excess(mz
->memcg
);
3430 * One school of thought says that we should not add
3431 * back the node to the tree if reclaim returns 0.
3432 * But our reclaim could return 0, simply because due
3433 * to priority we are exposing a smaller subset of
3434 * memory to reclaim from. Consider this as a longer
3437 /* If excess == 0, no tree ops */
3438 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
3439 spin_unlock_irq(&mctz
->lock
);
3440 css_put(&mz
->memcg
->css
);
3443 * Could not reclaim anything and there are no more
3444 * mem cgroups to try or we seem to be looping without
3445 * reclaiming anything.
3447 if (!nr_reclaimed
&&
3449 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3451 } while (!nr_reclaimed
);
3453 css_put(&next_mz
->memcg
->css
);
3454 return nr_reclaimed
;
3458 * Reclaims as many pages from the given memcg as possible.
3460 * Caller is responsible for holding css reference for memcg.
3462 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3464 int nr_retries
= MAX_RECLAIM_RETRIES
;
3466 /* we call try-to-free pages for make this cgroup empty */
3467 lru_add_drain_all();
3469 drain_all_stock(memcg
);
3471 /* try to free all pages in this cgroup */
3472 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
3475 if (signal_pending(current
))
3478 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
3482 /* maybe some writeback is necessary */
3483 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3491 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
3492 char *buf
, size_t nbytes
,
3495 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3497 if (mem_cgroup_is_root(memcg
))
3499 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
3502 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
3508 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
3509 struct cftype
*cft
, u64 val
)
3514 pr_warn_once("Non-hierarchical mode is deprecated. "
3515 "Please report your usecase to linux-mm@kvack.org if you "
3516 "depend on this functionality.\n");
3521 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3525 if (mem_cgroup_is_root(memcg
)) {
3526 /* mem_cgroup_threshold() calls here from irqsafe context */
3527 cgroup_rstat_flush_irqsafe(memcg
->css
.cgroup
);
3528 val
= memcg_page_state(memcg
, NR_FILE_PAGES
) +
3529 memcg_page_state(memcg
, NR_ANON_MAPPED
);
3531 val
+= memcg_page_state(memcg
, MEMCG_SWAP
);
3534 val
= page_counter_read(&memcg
->memory
);
3536 val
= page_counter_read(&memcg
->memsw
);
3549 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
3552 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3553 struct page_counter
*counter
;
3555 switch (MEMFILE_TYPE(cft
->private)) {
3557 counter
= &memcg
->memory
;
3560 counter
= &memcg
->memsw
;
3563 counter
= &memcg
->kmem
;
3566 counter
= &memcg
->tcpmem
;
3572 switch (MEMFILE_ATTR(cft
->private)) {
3574 if (counter
== &memcg
->memory
)
3575 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
3576 if (counter
== &memcg
->memsw
)
3577 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
3578 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
3580 return (u64
)counter
->max
* PAGE_SIZE
;
3582 return (u64
)counter
->watermark
* PAGE_SIZE
;
3584 return counter
->failcnt
;
3585 case RES_SOFT_LIMIT
:
3586 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
3592 #ifdef CONFIG_MEMCG_KMEM
3593 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3595 struct obj_cgroup
*objcg
;
3598 if (cgroup_memory_nokmem
)
3601 BUG_ON(memcg
->kmemcg_id
>= 0);
3602 BUG_ON(memcg
->kmem_state
);
3604 memcg_id
= memcg_alloc_cache_id();
3608 objcg
= obj_cgroup_alloc();
3610 memcg_free_cache_id(memcg_id
);
3613 objcg
->memcg
= memcg
;
3614 rcu_assign_pointer(memcg
->objcg
, objcg
);
3616 static_branch_enable(&memcg_kmem_enabled_key
);
3618 memcg
->kmemcg_id
= memcg_id
;
3619 memcg
->kmem_state
= KMEM_ONLINE
;
3624 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3626 struct cgroup_subsys_state
*css
;
3627 struct mem_cgroup
*parent
, *child
;
3630 if (memcg
->kmem_state
!= KMEM_ONLINE
)
3633 memcg
->kmem_state
= KMEM_ALLOCATED
;
3635 parent
= parent_mem_cgroup(memcg
);
3637 parent
= root_mem_cgroup
;
3639 memcg_reparent_objcgs(memcg
, parent
);
3641 kmemcg_id
= memcg
->kmemcg_id
;
3642 BUG_ON(kmemcg_id
< 0);
3645 * Change kmemcg_id of this cgroup and all its descendants to the
3646 * parent's id, and then move all entries from this cgroup's list_lrus
3647 * to ones of the parent. After we have finished, all list_lrus
3648 * corresponding to this cgroup are guaranteed to remain empty. The
3649 * ordering is imposed by list_lru_node->lock taken by
3650 * memcg_drain_all_list_lrus().
3652 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3653 css_for_each_descendant_pre(css
, &memcg
->css
) {
3654 child
= mem_cgroup_from_css(css
);
3655 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
3656 child
->kmemcg_id
= parent
->kmemcg_id
;
3660 memcg_drain_all_list_lrus(kmemcg_id
, parent
);
3662 memcg_free_cache_id(kmemcg_id
);
3665 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3667 /* css_alloc() failed, offlining didn't happen */
3668 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
3669 memcg_offline_kmem(memcg
);
3672 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3676 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3679 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3682 #endif /* CONFIG_MEMCG_KMEM */
3684 static int memcg_update_kmem_max(struct mem_cgroup
*memcg
,
3689 mutex_lock(&memcg_max_mutex
);
3690 ret
= page_counter_set_max(&memcg
->kmem
, max
);
3691 mutex_unlock(&memcg_max_mutex
);
3695 static int memcg_update_tcp_max(struct mem_cgroup
*memcg
, unsigned long max
)
3699 mutex_lock(&memcg_max_mutex
);
3701 ret
= page_counter_set_max(&memcg
->tcpmem
, max
);
3705 if (!memcg
->tcpmem_active
) {
3707 * The active flag needs to be written after the static_key
3708 * update. This is what guarantees that the socket activation
3709 * function is the last one to run. See mem_cgroup_sk_alloc()
3710 * for details, and note that we don't mark any socket as
3711 * belonging to this memcg until that flag is up.
3713 * We need to do this, because static_keys will span multiple
3714 * sites, but we can't control their order. If we mark a socket
3715 * as accounted, but the accounting functions are not patched in
3716 * yet, we'll lose accounting.
3718 * We never race with the readers in mem_cgroup_sk_alloc(),
3719 * because when this value change, the code to process it is not
3722 static_branch_inc(&memcg_sockets_enabled_key
);
3723 memcg
->tcpmem_active
= true;
3726 mutex_unlock(&memcg_max_mutex
);
3731 * The user of this function is...
3734 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
3735 char *buf
, size_t nbytes
, loff_t off
)
3737 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3738 unsigned long nr_pages
;
3741 buf
= strstrip(buf
);
3742 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
3746 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3748 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3752 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3754 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, false);
3757 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, true);
3760 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3761 "Please report your usecase to linux-mm@kvack.org if you "
3762 "depend on this functionality.\n");
3763 ret
= memcg_update_kmem_max(memcg
, nr_pages
);
3766 ret
= memcg_update_tcp_max(memcg
, nr_pages
);
3770 case RES_SOFT_LIMIT
:
3771 memcg
->soft_limit
= nr_pages
;
3775 return ret
?: nbytes
;
3778 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3779 size_t nbytes
, loff_t off
)
3781 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3782 struct page_counter
*counter
;
3784 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3786 counter
= &memcg
->memory
;
3789 counter
= &memcg
->memsw
;
3792 counter
= &memcg
->kmem
;
3795 counter
= &memcg
->tcpmem
;
3801 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3803 page_counter_reset_watermark(counter
);
3806 counter
->failcnt
= 0;
3815 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3818 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3822 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3823 struct cftype
*cft
, u64 val
)
3825 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3827 if (val
& ~MOVE_MASK
)
3831 * No kind of locking is needed in here, because ->can_attach() will
3832 * check this value once in the beginning of the process, and then carry
3833 * on with stale data. This means that changes to this value will only
3834 * affect task migrations starting after the change.
3836 memcg
->move_charge_at_immigrate
= val
;
3840 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3841 struct cftype
*cft
, u64 val
)
3849 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3850 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3851 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3853 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
3854 int nid
, unsigned int lru_mask
, bool tree
)
3856 struct lruvec
*lruvec
= mem_cgroup_lruvec(memcg
, NODE_DATA(nid
));
3857 unsigned long nr
= 0;
3860 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
3863 if (!(BIT(lru
) & lru_mask
))
3866 nr
+= lruvec_page_state(lruvec
, NR_LRU_BASE
+ lru
);
3868 nr
+= lruvec_page_state_local(lruvec
, NR_LRU_BASE
+ lru
);
3873 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
3874 unsigned int lru_mask
,
3877 unsigned long nr
= 0;
3881 if (!(BIT(lru
) & lru_mask
))
3884 nr
+= memcg_page_state(memcg
, NR_LRU_BASE
+ lru
);
3886 nr
+= memcg_page_state_local(memcg
, NR_LRU_BASE
+ lru
);
3891 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3895 unsigned int lru_mask
;
3898 static const struct numa_stat stats
[] = {
3899 { "total", LRU_ALL
},
3900 { "file", LRU_ALL_FILE
},
3901 { "anon", LRU_ALL_ANON
},
3902 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3904 const struct numa_stat
*stat
;
3906 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3908 cgroup_rstat_flush(memcg
->css
.cgroup
);
3910 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3911 seq_printf(m
, "%s=%lu", stat
->name
,
3912 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3914 for_each_node_state(nid
, N_MEMORY
)
3915 seq_printf(m
, " N%d=%lu", nid
,
3916 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3917 stat
->lru_mask
, false));
3921 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3923 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
,
3924 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3926 for_each_node_state(nid
, N_MEMORY
)
3927 seq_printf(m
, " N%d=%lu", nid
,
3928 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3929 stat
->lru_mask
, true));
3935 #endif /* CONFIG_NUMA */
3937 static const unsigned int memcg1_stats
[] = {
3940 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3950 static const char *const memcg1_stat_names
[] = {
3953 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
3963 /* Universal VM events cgroup1 shows, original sort order */
3964 static const unsigned int memcg1_events
[] = {
3971 static int memcg_stat_show(struct seq_file
*m
, void *v
)
3973 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3974 unsigned long memory
, memsw
;
3975 struct mem_cgroup
*mi
;
3978 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names
) != ARRAY_SIZE(memcg1_stats
));
3980 cgroup_rstat_flush(memcg
->css
.cgroup
);
3982 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
3985 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
3987 nr
= memcg_page_state_local(memcg
, memcg1_stats
[i
]);
3988 seq_printf(m
, "%s %lu\n", memcg1_stat_names
[i
], nr
* PAGE_SIZE
);
3991 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
3992 seq_printf(m
, "%s %lu\n", vm_event_name(memcg1_events
[i
]),
3993 memcg_events_local(memcg
, memcg1_events
[i
]));
3995 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
3996 seq_printf(m
, "%s %lu\n", lru_list_name(i
),
3997 memcg_page_state_local(memcg
, NR_LRU_BASE
+ i
) *
4000 /* Hierarchical information */
4001 memory
= memsw
= PAGE_COUNTER_MAX
;
4002 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
4003 memory
= min(memory
, READ_ONCE(mi
->memory
.max
));
4004 memsw
= min(memsw
, READ_ONCE(mi
->memsw
.max
));
4006 seq_printf(m
, "hierarchical_memory_limit %llu\n",
4007 (u64
)memory
* PAGE_SIZE
);
4008 if (do_memsw_account())
4009 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
4010 (u64
)memsw
* PAGE_SIZE
);
4012 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
4015 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
4017 nr
= memcg_page_state(memcg
, memcg1_stats
[i
]);
4018 seq_printf(m
, "total_%s %llu\n", memcg1_stat_names
[i
],
4019 (u64
)nr
* PAGE_SIZE
);
4022 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
4023 seq_printf(m
, "total_%s %llu\n",
4024 vm_event_name(memcg1_events
[i
]),
4025 (u64
)memcg_events(memcg
, memcg1_events
[i
]));
4027 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
4028 seq_printf(m
, "total_%s %llu\n", lru_list_name(i
),
4029 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
4032 #ifdef CONFIG_DEBUG_VM
4035 struct mem_cgroup_per_node
*mz
;
4036 unsigned long anon_cost
= 0;
4037 unsigned long file_cost
= 0;
4039 for_each_online_pgdat(pgdat
) {
4040 mz
= memcg
->nodeinfo
[pgdat
->node_id
];
4042 anon_cost
+= mz
->lruvec
.anon_cost
;
4043 file_cost
+= mz
->lruvec
.file_cost
;
4045 seq_printf(m
, "anon_cost %lu\n", anon_cost
);
4046 seq_printf(m
, "file_cost %lu\n", file_cost
);
4053 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
4056 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4058 return mem_cgroup_swappiness(memcg
);
4061 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
4062 struct cftype
*cft
, u64 val
)
4064 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4069 if (!mem_cgroup_is_root(memcg
))
4070 memcg
->swappiness
= val
;
4072 vm_swappiness
= val
;
4077 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
4079 struct mem_cgroup_threshold_ary
*t
;
4080 unsigned long usage
;
4085 t
= rcu_dereference(memcg
->thresholds
.primary
);
4087 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
4092 usage
= mem_cgroup_usage(memcg
, swap
);
4095 * current_threshold points to threshold just below or equal to usage.
4096 * If it's not true, a threshold was crossed after last
4097 * call of __mem_cgroup_threshold().
4099 i
= t
->current_threshold
;
4102 * Iterate backward over array of thresholds starting from
4103 * current_threshold and check if a threshold is crossed.
4104 * If none of thresholds below usage is crossed, we read
4105 * only one element of the array here.
4107 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
4108 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4110 /* i = current_threshold + 1 */
4114 * Iterate forward over array of thresholds starting from
4115 * current_threshold+1 and check if a threshold is crossed.
4116 * If none of thresholds above usage is crossed, we read
4117 * only one element of the array here.
4119 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
4120 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4122 /* Update current_threshold */
4123 t
->current_threshold
= i
- 1;
4128 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
4131 __mem_cgroup_threshold(memcg
, false);
4132 if (do_memsw_account())
4133 __mem_cgroup_threshold(memcg
, true);
4135 memcg
= parent_mem_cgroup(memcg
);
4139 static int compare_thresholds(const void *a
, const void *b
)
4141 const struct mem_cgroup_threshold
*_a
= a
;
4142 const struct mem_cgroup_threshold
*_b
= b
;
4144 if (_a
->threshold
> _b
->threshold
)
4147 if (_a
->threshold
< _b
->threshold
)
4153 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
4155 struct mem_cgroup_eventfd_list
*ev
;
4157 spin_lock(&memcg_oom_lock
);
4159 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
4160 eventfd_signal(ev
->eventfd
, 1);
4162 spin_unlock(&memcg_oom_lock
);
4166 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
4168 struct mem_cgroup
*iter
;
4170 for_each_mem_cgroup_tree(iter
, memcg
)
4171 mem_cgroup_oom_notify_cb(iter
);
4174 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4175 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
4177 struct mem_cgroup_thresholds
*thresholds
;
4178 struct mem_cgroup_threshold_ary
*new;
4179 unsigned long threshold
;
4180 unsigned long usage
;
4183 ret
= page_counter_memparse(args
, "-1", &threshold
);
4187 mutex_lock(&memcg
->thresholds_lock
);
4190 thresholds
= &memcg
->thresholds
;
4191 usage
= mem_cgroup_usage(memcg
, false);
4192 } else if (type
== _MEMSWAP
) {
4193 thresholds
= &memcg
->memsw_thresholds
;
4194 usage
= mem_cgroup_usage(memcg
, true);
4198 /* Check if a threshold crossed before adding a new one */
4199 if (thresholds
->primary
)
4200 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4202 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4204 /* Allocate memory for new array of thresholds */
4205 new = kmalloc(struct_size(new, entries
, size
), GFP_KERNEL
);
4212 /* Copy thresholds (if any) to new array */
4213 if (thresholds
->primary
)
4214 memcpy(new->entries
, thresholds
->primary
->entries
,
4215 flex_array_size(new, entries
, size
- 1));
4217 /* Add new threshold */
4218 new->entries
[size
- 1].eventfd
= eventfd
;
4219 new->entries
[size
- 1].threshold
= threshold
;
4221 /* Sort thresholds. Registering of new threshold isn't time-critical */
4222 sort(new->entries
, size
, sizeof(*new->entries
),
4223 compare_thresholds
, NULL
);
4225 /* Find current threshold */
4226 new->current_threshold
= -1;
4227 for (i
= 0; i
< size
; i
++) {
4228 if (new->entries
[i
].threshold
<= usage
) {
4230 * new->current_threshold will not be used until
4231 * rcu_assign_pointer(), so it's safe to increment
4234 ++new->current_threshold
;
4239 /* Free old spare buffer and save old primary buffer as spare */
4240 kfree(thresholds
->spare
);
4241 thresholds
->spare
= thresholds
->primary
;
4243 rcu_assign_pointer(thresholds
->primary
, new);
4245 /* To be sure that nobody uses thresholds */
4249 mutex_unlock(&memcg
->thresholds_lock
);
4254 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4255 struct eventfd_ctx
*eventfd
, const char *args
)
4257 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
4260 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4261 struct eventfd_ctx
*eventfd
, const char *args
)
4263 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
4266 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4267 struct eventfd_ctx
*eventfd
, enum res_type type
)
4269 struct mem_cgroup_thresholds
*thresholds
;
4270 struct mem_cgroup_threshold_ary
*new;
4271 unsigned long usage
;
4272 int i
, j
, size
, entries
;
4274 mutex_lock(&memcg
->thresholds_lock
);
4277 thresholds
= &memcg
->thresholds
;
4278 usage
= mem_cgroup_usage(memcg
, false);
4279 } else if (type
== _MEMSWAP
) {
4280 thresholds
= &memcg
->memsw_thresholds
;
4281 usage
= mem_cgroup_usage(memcg
, true);
4285 if (!thresholds
->primary
)
4288 /* Check if a threshold crossed before removing */
4289 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4291 /* Calculate new number of threshold */
4293 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4294 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4300 new = thresholds
->spare
;
4302 /* If no items related to eventfd have been cleared, nothing to do */
4306 /* Set thresholds array to NULL if we don't have thresholds */
4315 /* Copy thresholds and find current threshold */
4316 new->current_threshold
= -1;
4317 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4318 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4321 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4322 if (new->entries
[j
].threshold
<= usage
) {
4324 * new->current_threshold will not be used
4325 * until rcu_assign_pointer(), so it's safe to increment
4328 ++new->current_threshold
;
4334 /* Swap primary and spare array */
4335 thresholds
->spare
= thresholds
->primary
;
4337 rcu_assign_pointer(thresholds
->primary
, new);
4339 /* To be sure that nobody uses thresholds */
4342 /* If all events are unregistered, free the spare array */
4344 kfree(thresholds
->spare
);
4345 thresholds
->spare
= NULL
;
4348 mutex_unlock(&memcg
->thresholds_lock
);
4351 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4352 struct eventfd_ctx
*eventfd
)
4354 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
4357 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4358 struct eventfd_ctx
*eventfd
)
4360 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
4363 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
4364 struct eventfd_ctx
*eventfd
, const char *args
)
4366 struct mem_cgroup_eventfd_list
*event
;
4368 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4372 spin_lock(&memcg_oom_lock
);
4374 event
->eventfd
= eventfd
;
4375 list_add(&event
->list
, &memcg
->oom_notify
);
4377 /* already in OOM ? */
4378 if (memcg
->under_oom
)
4379 eventfd_signal(eventfd
, 1);
4380 spin_unlock(&memcg_oom_lock
);
4385 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
4386 struct eventfd_ctx
*eventfd
)
4388 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4390 spin_lock(&memcg_oom_lock
);
4392 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4393 if (ev
->eventfd
== eventfd
) {
4394 list_del(&ev
->list
);
4399 spin_unlock(&memcg_oom_lock
);
4402 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
4404 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(sf
);
4406 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
4407 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
4408 seq_printf(sf
, "oom_kill %lu\n",
4409 atomic_long_read(&memcg
->memory_events
[MEMCG_OOM_KILL
]));
4413 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
4414 struct cftype
*cft
, u64 val
)
4416 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4418 /* cannot set to root cgroup and only 0 and 1 are allowed */
4419 if (mem_cgroup_is_root(memcg
) || !((val
== 0) || (val
== 1)))
4422 memcg
->oom_kill_disable
= val
;
4424 memcg_oom_recover(memcg
);
4429 #ifdef CONFIG_CGROUP_WRITEBACK
4431 #include <trace/events/writeback.h>
4433 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4435 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
4438 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4440 wb_domain_exit(&memcg
->cgwb_domain
);
4443 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4445 wb_domain_size_changed(&memcg
->cgwb_domain
);
4448 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
4450 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4452 if (!memcg
->css
.parent
)
4455 return &memcg
->cgwb_domain
;
4459 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4460 * @wb: bdi_writeback in question
4461 * @pfilepages: out parameter for number of file pages
4462 * @pheadroom: out parameter for number of allocatable pages according to memcg
4463 * @pdirty: out parameter for number of dirty pages
4464 * @pwriteback: out parameter for number of pages under writeback
4466 * Determine the numbers of file, headroom, dirty, and writeback pages in
4467 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4468 * is a bit more involved.
4470 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4471 * headroom is calculated as the lowest headroom of itself and the
4472 * ancestors. Note that this doesn't consider the actual amount of
4473 * available memory in the system. The caller should further cap
4474 * *@pheadroom accordingly.
4476 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
4477 unsigned long *pheadroom
, unsigned long *pdirty
,
4478 unsigned long *pwriteback
)
4480 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4481 struct mem_cgroup
*parent
;
4483 cgroup_rstat_flush_irqsafe(memcg
->css
.cgroup
);
4485 *pdirty
= memcg_page_state(memcg
, NR_FILE_DIRTY
);
4486 *pwriteback
= memcg_page_state(memcg
, NR_WRITEBACK
);
4487 *pfilepages
= memcg_page_state(memcg
, NR_INACTIVE_FILE
) +
4488 memcg_page_state(memcg
, NR_ACTIVE_FILE
);
4490 *pheadroom
= PAGE_COUNTER_MAX
;
4491 while ((parent
= parent_mem_cgroup(memcg
))) {
4492 unsigned long ceiling
= min(READ_ONCE(memcg
->memory
.max
),
4493 READ_ONCE(memcg
->memory
.high
));
4494 unsigned long used
= page_counter_read(&memcg
->memory
);
4496 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
4502 * Foreign dirty flushing
4504 * There's an inherent mismatch between memcg and writeback. The former
4505 * tracks ownership per-page while the latter per-inode. This was a
4506 * deliberate design decision because honoring per-page ownership in the
4507 * writeback path is complicated, may lead to higher CPU and IO overheads
4508 * and deemed unnecessary given that write-sharing an inode across
4509 * different cgroups isn't a common use-case.
4511 * Combined with inode majority-writer ownership switching, this works well
4512 * enough in most cases but there are some pathological cases. For
4513 * example, let's say there are two cgroups A and B which keep writing to
4514 * different but confined parts of the same inode. B owns the inode and
4515 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4516 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4517 * triggering background writeback. A will be slowed down without a way to
4518 * make writeback of the dirty pages happen.
4520 * Conditions like the above can lead to a cgroup getting repeatedly and
4521 * severely throttled after making some progress after each
4522 * dirty_expire_interval while the underlying IO device is almost
4525 * Solving this problem completely requires matching the ownership tracking
4526 * granularities between memcg and writeback in either direction. However,
4527 * the more egregious behaviors can be avoided by simply remembering the
4528 * most recent foreign dirtying events and initiating remote flushes on
4529 * them when local writeback isn't enough to keep the memory clean enough.
4531 * The following two functions implement such mechanism. When a foreign
4532 * page - a page whose memcg and writeback ownerships don't match - is
4533 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4534 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4535 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4536 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4537 * foreign bdi_writebacks which haven't expired. Both the numbers of
4538 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4539 * limited to MEMCG_CGWB_FRN_CNT.
4541 * The mechanism only remembers IDs and doesn't hold any object references.
4542 * As being wrong occasionally doesn't matter, updates and accesses to the
4543 * records are lockless and racy.
4545 void mem_cgroup_track_foreign_dirty_slowpath(struct page
*page
,
4546 struct bdi_writeback
*wb
)
4548 struct mem_cgroup
*memcg
= page_memcg(page
);
4549 struct memcg_cgwb_frn
*frn
;
4550 u64 now
= get_jiffies_64();
4551 u64 oldest_at
= now
;
4555 trace_track_foreign_dirty(page
, wb
);
4558 * Pick the slot to use. If there is already a slot for @wb, keep
4559 * using it. If not replace the oldest one which isn't being
4562 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4563 frn
= &memcg
->cgwb_frn
[i
];
4564 if (frn
->bdi_id
== wb
->bdi
->id
&&
4565 frn
->memcg_id
== wb
->memcg_css
->id
)
4567 if (time_before64(frn
->at
, oldest_at
) &&
4568 atomic_read(&frn
->done
.cnt
) == 1) {
4570 oldest_at
= frn
->at
;
4574 if (i
< MEMCG_CGWB_FRN_CNT
) {
4576 * Re-using an existing one. Update timestamp lazily to
4577 * avoid making the cacheline hot. We want them to be
4578 * reasonably up-to-date and significantly shorter than
4579 * dirty_expire_interval as that's what expires the record.
4580 * Use the shorter of 1s and dirty_expire_interval / 8.
4582 unsigned long update_intv
=
4583 min_t(unsigned long, HZ
,
4584 msecs_to_jiffies(dirty_expire_interval
* 10) / 8);
4586 if (time_before64(frn
->at
, now
- update_intv
))
4588 } else if (oldest
>= 0) {
4589 /* replace the oldest free one */
4590 frn
= &memcg
->cgwb_frn
[oldest
];
4591 frn
->bdi_id
= wb
->bdi
->id
;
4592 frn
->memcg_id
= wb
->memcg_css
->id
;
4597 /* issue foreign writeback flushes for recorded foreign dirtying events */
4598 void mem_cgroup_flush_foreign(struct bdi_writeback
*wb
)
4600 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4601 unsigned long intv
= msecs_to_jiffies(dirty_expire_interval
* 10);
4602 u64 now
= jiffies_64
;
4605 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4606 struct memcg_cgwb_frn
*frn
= &memcg
->cgwb_frn
[i
];
4609 * If the record is older than dirty_expire_interval,
4610 * writeback on it has already started. No need to kick it
4611 * off again. Also, don't start a new one if there's
4612 * already one in flight.
4614 if (time_after64(frn
->at
, now
- intv
) &&
4615 atomic_read(&frn
->done
.cnt
) == 1) {
4617 trace_flush_foreign(wb
, frn
->bdi_id
, frn
->memcg_id
);
4618 cgroup_writeback_by_id(frn
->bdi_id
, frn
->memcg_id
,
4619 WB_REASON_FOREIGN_FLUSH
,
4625 #else /* CONFIG_CGROUP_WRITEBACK */
4627 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4632 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4636 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4640 #endif /* CONFIG_CGROUP_WRITEBACK */
4643 * DO NOT USE IN NEW FILES.
4645 * "cgroup.event_control" implementation.
4647 * This is way over-engineered. It tries to support fully configurable
4648 * events for each user. Such level of flexibility is completely
4649 * unnecessary especially in the light of the planned unified hierarchy.
4651 * Please deprecate this and replace with something simpler if at all
4656 * Unregister event and free resources.
4658 * Gets called from workqueue.
4660 static void memcg_event_remove(struct work_struct
*work
)
4662 struct mem_cgroup_event
*event
=
4663 container_of(work
, struct mem_cgroup_event
, remove
);
4664 struct mem_cgroup
*memcg
= event
->memcg
;
4666 remove_wait_queue(event
->wqh
, &event
->wait
);
4668 event
->unregister_event(memcg
, event
->eventfd
);
4670 /* Notify userspace the event is going away. */
4671 eventfd_signal(event
->eventfd
, 1);
4673 eventfd_ctx_put(event
->eventfd
);
4675 css_put(&memcg
->css
);
4679 * Gets called on EPOLLHUP on eventfd when user closes it.
4681 * Called with wqh->lock held and interrupts disabled.
4683 static int memcg_event_wake(wait_queue_entry_t
*wait
, unsigned mode
,
4684 int sync
, void *key
)
4686 struct mem_cgroup_event
*event
=
4687 container_of(wait
, struct mem_cgroup_event
, wait
);
4688 struct mem_cgroup
*memcg
= event
->memcg
;
4689 __poll_t flags
= key_to_poll(key
);
4691 if (flags
& EPOLLHUP
) {
4693 * If the event has been detached at cgroup removal, we
4694 * can simply return knowing the other side will cleanup
4697 * We can't race against event freeing since the other
4698 * side will require wqh->lock via remove_wait_queue(),
4701 spin_lock(&memcg
->event_list_lock
);
4702 if (!list_empty(&event
->list
)) {
4703 list_del_init(&event
->list
);
4705 * We are in atomic context, but cgroup_event_remove()
4706 * may sleep, so we have to call it in workqueue.
4708 schedule_work(&event
->remove
);
4710 spin_unlock(&memcg
->event_list_lock
);
4716 static void memcg_event_ptable_queue_proc(struct file
*file
,
4717 wait_queue_head_t
*wqh
, poll_table
*pt
)
4719 struct mem_cgroup_event
*event
=
4720 container_of(pt
, struct mem_cgroup_event
, pt
);
4723 add_wait_queue(wqh
, &event
->wait
);
4727 * DO NOT USE IN NEW FILES.
4729 * Parse input and register new cgroup event handler.
4731 * Input must be in format '<event_fd> <control_fd> <args>'.
4732 * Interpretation of args is defined by control file implementation.
4734 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
4735 char *buf
, size_t nbytes
, loff_t off
)
4737 struct cgroup_subsys_state
*css
= of_css(of
);
4738 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4739 struct mem_cgroup_event
*event
;
4740 struct cgroup_subsys_state
*cfile_css
;
4741 unsigned int efd
, cfd
;
4748 buf
= strstrip(buf
);
4750 efd
= simple_strtoul(buf
, &endp
, 10);
4755 cfd
= simple_strtoul(buf
, &endp
, 10);
4756 if ((*endp
!= ' ') && (*endp
!= '\0'))
4760 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
4764 event
->memcg
= memcg
;
4765 INIT_LIST_HEAD(&event
->list
);
4766 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
4767 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
4768 INIT_WORK(&event
->remove
, memcg_event_remove
);
4776 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
4777 if (IS_ERR(event
->eventfd
)) {
4778 ret
= PTR_ERR(event
->eventfd
);
4785 goto out_put_eventfd
;
4788 /* the process need read permission on control file */
4789 /* AV: shouldn't we check that it's been opened for read instead? */
4790 ret
= file_permission(cfile
.file
, MAY_READ
);
4795 * Determine the event callbacks and set them in @event. This used
4796 * to be done via struct cftype but cgroup core no longer knows
4797 * about these events. The following is crude but the whole thing
4798 * is for compatibility anyway.
4800 * DO NOT ADD NEW FILES.
4802 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
4804 if (!strcmp(name
, "memory.usage_in_bytes")) {
4805 event
->register_event
= mem_cgroup_usage_register_event
;
4806 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
4807 } else if (!strcmp(name
, "memory.oom_control")) {
4808 event
->register_event
= mem_cgroup_oom_register_event
;
4809 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
4810 } else if (!strcmp(name
, "memory.pressure_level")) {
4811 event
->register_event
= vmpressure_register_event
;
4812 event
->unregister_event
= vmpressure_unregister_event
;
4813 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
4814 event
->register_event
= memsw_cgroup_usage_register_event
;
4815 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
4822 * Verify @cfile should belong to @css. Also, remaining events are
4823 * automatically removed on cgroup destruction but the removal is
4824 * asynchronous, so take an extra ref on @css.
4826 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
4827 &memory_cgrp_subsys
);
4829 if (IS_ERR(cfile_css
))
4831 if (cfile_css
!= css
) {
4836 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
4840 vfs_poll(efile
.file
, &event
->pt
);
4842 spin_lock_irq(&memcg
->event_list_lock
);
4843 list_add(&event
->list
, &memcg
->event_list
);
4844 spin_unlock_irq(&memcg
->event_list_lock
);
4856 eventfd_ctx_put(event
->eventfd
);
4865 static struct cftype mem_cgroup_legacy_files
[] = {
4867 .name
= "usage_in_bytes",
4868 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4869 .read_u64
= mem_cgroup_read_u64
,
4872 .name
= "max_usage_in_bytes",
4873 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4874 .write
= mem_cgroup_reset
,
4875 .read_u64
= mem_cgroup_read_u64
,
4878 .name
= "limit_in_bytes",
4879 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4880 .write
= mem_cgroup_write
,
4881 .read_u64
= mem_cgroup_read_u64
,
4884 .name
= "soft_limit_in_bytes",
4885 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4886 .write
= mem_cgroup_write
,
4887 .read_u64
= mem_cgroup_read_u64
,
4891 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4892 .write
= mem_cgroup_reset
,
4893 .read_u64
= mem_cgroup_read_u64
,
4897 .seq_show
= memcg_stat_show
,
4900 .name
= "force_empty",
4901 .write
= mem_cgroup_force_empty_write
,
4904 .name
= "use_hierarchy",
4905 .write_u64
= mem_cgroup_hierarchy_write
,
4906 .read_u64
= mem_cgroup_hierarchy_read
,
4909 .name
= "cgroup.event_control", /* XXX: for compat */
4910 .write
= memcg_write_event_control
,
4911 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
4914 .name
= "swappiness",
4915 .read_u64
= mem_cgroup_swappiness_read
,
4916 .write_u64
= mem_cgroup_swappiness_write
,
4919 .name
= "move_charge_at_immigrate",
4920 .read_u64
= mem_cgroup_move_charge_read
,
4921 .write_u64
= mem_cgroup_move_charge_write
,
4924 .name
= "oom_control",
4925 .seq_show
= mem_cgroup_oom_control_read
,
4926 .write_u64
= mem_cgroup_oom_control_write
,
4927 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4930 .name
= "pressure_level",
4934 .name
= "numa_stat",
4935 .seq_show
= memcg_numa_stat_show
,
4939 .name
= "kmem.limit_in_bytes",
4940 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4941 .write
= mem_cgroup_write
,
4942 .read_u64
= mem_cgroup_read_u64
,
4945 .name
= "kmem.usage_in_bytes",
4946 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4947 .read_u64
= mem_cgroup_read_u64
,
4950 .name
= "kmem.failcnt",
4951 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
4952 .write
= mem_cgroup_reset
,
4953 .read_u64
= mem_cgroup_read_u64
,
4956 .name
= "kmem.max_usage_in_bytes",
4957 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
4958 .write
= mem_cgroup_reset
,
4959 .read_u64
= mem_cgroup_read_u64
,
4961 #if defined(CONFIG_MEMCG_KMEM) && \
4962 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
4964 .name
= "kmem.slabinfo",
4965 .seq_show
= memcg_slab_show
,
4969 .name
= "kmem.tcp.limit_in_bytes",
4970 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
4971 .write
= mem_cgroup_write
,
4972 .read_u64
= mem_cgroup_read_u64
,
4975 .name
= "kmem.tcp.usage_in_bytes",
4976 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
4977 .read_u64
= mem_cgroup_read_u64
,
4980 .name
= "kmem.tcp.failcnt",
4981 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
4982 .write
= mem_cgroup_reset
,
4983 .read_u64
= mem_cgroup_read_u64
,
4986 .name
= "kmem.tcp.max_usage_in_bytes",
4987 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
4988 .write
= mem_cgroup_reset
,
4989 .read_u64
= mem_cgroup_read_u64
,
4991 { }, /* terminate */
4995 * Private memory cgroup IDR
4997 * Swap-out records and page cache shadow entries need to store memcg
4998 * references in constrained space, so we maintain an ID space that is
4999 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
5000 * memory-controlled cgroups to 64k.
5002 * However, there usually are many references to the offline CSS after
5003 * the cgroup has been destroyed, such as page cache or reclaimable
5004 * slab objects, that don't need to hang on to the ID. We want to keep
5005 * those dead CSS from occupying IDs, or we might quickly exhaust the
5006 * relatively small ID space and prevent the creation of new cgroups
5007 * even when there are much fewer than 64k cgroups - possibly none.
5009 * Maintain a private 16-bit ID space for memcg, and allow the ID to
5010 * be freed and recycled when it's no longer needed, which is usually
5011 * when the CSS is offlined.
5013 * The only exception to that are records of swapped out tmpfs/shmem
5014 * pages that need to be attributed to live ancestors on swapin. But
5015 * those references are manageable from userspace.
5018 static DEFINE_IDR(mem_cgroup_idr
);
5020 static void mem_cgroup_id_remove(struct mem_cgroup
*memcg
)
5022 if (memcg
->id
.id
> 0) {
5023 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
5028 static void __maybe_unused
mem_cgroup_id_get_many(struct mem_cgroup
*memcg
,
5031 refcount_add(n
, &memcg
->id
.ref
);
5034 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
5036 if (refcount_sub_and_test(n
, &memcg
->id
.ref
)) {
5037 mem_cgroup_id_remove(memcg
);
5039 /* Memcg ID pins CSS */
5040 css_put(&memcg
->css
);
5044 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
5046 mem_cgroup_id_put_many(memcg
, 1);
5050 * mem_cgroup_from_id - look up a memcg from a memcg id
5051 * @id: the memcg id to look up
5053 * Caller must hold rcu_read_lock().
5055 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
5057 WARN_ON_ONCE(!rcu_read_lock_held());
5058 return idr_find(&mem_cgroup_idr
, id
);
5061 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
5063 struct mem_cgroup_per_node
*pn
;
5066 * This routine is called against possible nodes.
5067 * But it's BUG to call kmalloc() against offline node.
5069 * TODO: this routine can waste much memory for nodes which will
5070 * never be onlined. It's better to use memory hotplug callback
5073 if (!node_state(node
, N_NORMAL_MEMORY
))
5075 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
5079 pn
->lruvec_stats_percpu
= alloc_percpu_gfp(struct lruvec_stats_percpu
,
5080 GFP_KERNEL_ACCOUNT
);
5081 if (!pn
->lruvec_stats_percpu
) {
5086 lruvec_init(&pn
->lruvec
);
5087 pn
->usage_in_excess
= 0;
5088 pn
->on_tree
= false;
5091 memcg
->nodeinfo
[node
] = pn
;
5095 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
5097 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
5102 free_percpu(pn
->lruvec_stats_percpu
);
5106 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
5111 free_mem_cgroup_per_node_info(memcg
, node
);
5112 free_percpu(memcg
->vmstats_percpu
);
5116 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
5118 memcg_wb_domain_exit(memcg
);
5119 __mem_cgroup_free(memcg
);
5122 static struct mem_cgroup
*mem_cgroup_alloc(void)
5124 struct mem_cgroup
*memcg
;
5127 int __maybe_unused i
;
5128 long error
= -ENOMEM
;
5130 size
= sizeof(struct mem_cgroup
);
5131 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
5133 memcg
= kzalloc(size
, GFP_KERNEL
);
5135 return ERR_PTR(error
);
5137 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
5138 1, MEM_CGROUP_ID_MAX
,
5140 if (memcg
->id
.id
< 0) {
5141 error
= memcg
->id
.id
;
5145 memcg
->vmstats_percpu
= alloc_percpu_gfp(struct memcg_vmstats_percpu
,
5146 GFP_KERNEL_ACCOUNT
);
5147 if (!memcg
->vmstats_percpu
)
5151 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
5154 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
5157 INIT_WORK(&memcg
->high_work
, high_work_func
);
5158 INIT_LIST_HEAD(&memcg
->oom_notify
);
5159 mutex_init(&memcg
->thresholds_lock
);
5160 spin_lock_init(&memcg
->move_lock
);
5161 vmpressure_init(&memcg
->vmpressure
);
5162 INIT_LIST_HEAD(&memcg
->event_list
);
5163 spin_lock_init(&memcg
->event_list_lock
);
5164 memcg
->socket_pressure
= jiffies
;
5165 #ifdef CONFIG_MEMCG_KMEM
5166 memcg
->kmemcg_id
= -1;
5167 INIT_LIST_HEAD(&memcg
->objcg_list
);
5169 #ifdef CONFIG_CGROUP_WRITEBACK
5170 INIT_LIST_HEAD(&memcg
->cgwb_list
);
5171 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5172 memcg
->cgwb_frn
[i
].done
=
5173 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq
);
5175 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5176 spin_lock_init(&memcg
->deferred_split_queue
.split_queue_lock
);
5177 INIT_LIST_HEAD(&memcg
->deferred_split_queue
.split_queue
);
5178 memcg
->deferred_split_queue
.split_queue_len
= 0;
5180 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
5183 mem_cgroup_id_remove(memcg
);
5184 __mem_cgroup_free(memcg
);
5185 return ERR_PTR(error
);
5188 static struct cgroup_subsys_state
* __ref
5189 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
5191 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
5192 struct mem_cgroup
*memcg
, *old_memcg
;
5193 long error
= -ENOMEM
;
5195 old_memcg
= set_active_memcg(parent
);
5196 memcg
= mem_cgroup_alloc();
5197 set_active_memcg(old_memcg
);
5199 return ERR_CAST(memcg
);
5201 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5202 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5203 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5205 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
5206 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
5208 page_counter_init(&memcg
->memory
, &parent
->memory
);
5209 page_counter_init(&memcg
->swap
, &parent
->swap
);
5210 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
5211 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
5213 page_counter_init(&memcg
->memory
, NULL
);
5214 page_counter_init(&memcg
->swap
, NULL
);
5215 page_counter_init(&memcg
->kmem
, NULL
);
5216 page_counter_init(&memcg
->tcpmem
, NULL
);
5218 root_mem_cgroup
= memcg
;
5222 /* The following stuff does not apply to the root */
5223 error
= memcg_online_kmem(memcg
);
5227 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5228 static_branch_inc(&memcg_sockets_enabled_key
);
5232 mem_cgroup_id_remove(memcg
);
5233 mem_cgroup_free(memcg
);
5234 return ERR_PTR(error
);
5237 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
5239 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5242 * A memcg must be visible for expand_shrinker_info()
5243 * by the time the maps are allocated. So, we allocate maps
5244 * here, when for_each_mem_cgroup() can't skip it.
5246 if (alloc_shrinker_info(memcg
)) {
5247 mem_cgroup_id_remove(memcg
);
5251 /* Online state pins memcg ID, memcg ID pins CSS */
5252 refcount_set(&memcg
->id
.ref
, 1);
5255 if (unlikely(mem_cgroup_is_root(memcg
)))
5256 queue_delayed_work(system_unbound_wq
, &stats_flush_dwork
,
5261 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
5263 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5264 struct mem_cgroup_event
*event
, *tmp
;
5267 * Unregister events and notify userspace.
5268 * Notify userspace about cgroup removing only after rmdir of cgroup
5269 * directory to avoid race between userspace and kernelspace.
5271 spin_lock_irq(&memcg
->event_list_lock
);
5272 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
5273 list_del_init(&event
->list
);
5274 schedule_work(&event
->remove
);
5276 spin_unlock_irq(&memcg
->event_list_lock
);
5278 page_counter_set_min(&memcg
->memory
, 0);
5279 page_counter_set_low(&memcg
->memory
, 0);
5281 memcg_offline_kmem(memcg
);
5282 reparent_shrinker_deferred(memcg
);
5283 wb_memcg_offline(memcg
);
5285 drain_all_stock(memcg
);
5287 mem_cgroup_id_put(memcg
);
5290 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
5292 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5294 invalidate_reclaim_iterators(memcg
);
5297 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
5299 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5300 int __maybe_unused i
;
5302 #ifdef CONFIG_CGROUP_WRITEBACK
5303 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5304 wb_wait_for_completion(&memcg
->cgwb_frn
[i
].done
);
5306 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5307 static_branch_dec(&memcg_sockets_enabled_key
);
5309 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
5310 static_branch_dec(&memcg_sockets_enabled_key
);
5312 vmpressure_cleanup(&memcg
->vmpressure
);
5313 cancel_work_sync(&memcg
->high_work
);
5314 mem_cgroup_remove_from_trees(memcg
);
5315 free_shrinker_info(memcg
);
5316 memcg_free_kmem(memcg
);
5317 mem_cgroup_free(memcg
);
5321 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5322 * @css: the target css
5324 * Reset the states of the mem_cgroup associated with @css. This is
5325 * invoked when the userland requests disabling on the default hierarchy
5326 * but the memcg is pinned through dependency. The memcg should stop
5327 * applying policies and should revert to the vanilla state as it may be
5328 * made visible again.
5330 * The current implementation only resets the essential configurations.
5331 * This needs to be expanded to cover all the visible parts.
5333 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
5335 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5337 page_counter_set_max(&memcg
->memory
, PAGE_COUNTER_MAX
);
5338 page_counter_set_max(&memcg
->swap
, PAGE_COUNTER_MAX
);
5339 page_counter_set_max(&memcg
->kmem
, PAGE_COUNTER_MAX
);
5340 page_counter_set_max(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
5341 page_counter_set_min(&memcg
->memory
, 0);
5342 page_counter_set_low(&memcg
->memory
, 0);
5343 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5344 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5345 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5346 memcg_wb_domain_size_changed(memcg
);
5349 void mem_cgroup_flush_stats(void)
5351 if (!spin_trylock(&stats_flush_lock
))
5354 cgroup_rstat_flush_irqsafe(root_mem_cgroup
->css
.cgroup
);
5355 spin_unlock(&stats_flush_lock
);
5358 static void flush_memcg_stats_dwork(struct work_struct
*w
)
5360 mem_cgroup_flush_stats();
5361 queue_delayed_work(system_unbound_wq
, &stats_flush_dwork
, 2UL*HZ
);
5364 static void flush_memcg_stats_work(struct work_struct
*w
)
5366 mem_cgroup_flush_stats();
5369 static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state
*css
, int cpu
)
5371 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5372 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5373 struct memcg_vmstats_percpu
*statc
;
5377 statc
= per_cpu_ptr(memcg
->vmstats_percpu
, cpu
);
5379 for (i
= 0; i
< MEMCG_NR_STAT
; i
++) {
5381 * Collect the aggregated propagation counts of groups
5382 * below us. We're in a per-cpu loop here and this is
5383 * a global counter, so the first cycle will get them.
5385 delta
= memcg
->vmstats
.state_pending
[i
];
5387 memcg
->vmstats
.state_pending
[i
] = 0;
5389 /* Add CPU changes on this level since the last flush */
5390 v
= READ_ONCE(statc
->state
[i
]);
5391 if (v
!= statc
->state_prev
[i
]) {
5392 delta
+= v
- statc
->state_prev
[i
];
5393 statc
->state_prev
[i
] = v
;
5399 /* Aggregate counts on this level and propagate upwards */
5400 memcg
->vmstats
.state
[i
] += delta
;
5402 parent
->vmstats
.state_pending
[i
] += delta
;
5405 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++) {
5406 delta
= memcg
->vmstats
.events_pending
[i
];
5408 memcg
->vmstats
.events_pending
[i
] = 0;
5410 v
= READ_ONCE(statc
->events
[i
]);
5411 if (v
!= statc
->events_prev
[i
]) {
5412 delta
+= v
- statc
->events_prev
[i
];
5413 statc
->events_prev
[i
] = v
;
5419 memcg
->vmstats
.events
[i
] += delta
;
5421 parent
->vmstats
.events_pending
[i
] += delta
;
5424 for_each_node_state(nid
, N_MEMORY
) {
5425 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[nid
];
5426 struct mem_cgroup_per_node
*ppn
= NULL
;
5427 struct lruvec_stats_percpu
*lstatc
;
5430 ppn
= parent
->nodeinfo
[nid
];
5432 lstatc
= per_cpu_ptr(pn
->lruvec_stats_percpu
, cpu
);
5434 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++) {
5435 delta
= pn
->lruvec_stats
.state_pending
[i
];
5437 pn
->lruvec_stats
.state_pending
[i
] = 0;
5439 v
= READ_ONCE(lstatc
->state
[i
]);
5440 if (v
!= lstatc
->state_prev
[i
]) {
5441 delta
+= v
- lstatc
->state_prev
[i
];
5442 lstatc
->state_prev
[i
] = v
;
5448 pn
->lruvec_stats
.state
[i
] += delta
;
5450 ppn
->lruvec_stats
.state_pending
[i
] += delta
;
5456 /* Handlers for move charge at task migration. */
5457 static int mem_cgroup_do_precharge(unsigned long count
)
5461 /* Try a single bulk charge without reclaim first, kswapd may wake */
5462 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
5464 mc
.precharge
+= count
;
5468 /* Try charges one by one with reclaim, but do not retry */
5470 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
5484 enum mc_target_type
{
5491 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
5492 unsigned long addr
, pte_t ptent
)
5494 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
5496 if (!page
|| !page_mapped(page
))
5498 if (PageAnon(page
)) {
5499 if (!(mc
.flags
& MOVE_ANON
))
5502 if (!(mc
.flags
& MOVE_FILE
))
5505 if (!get_page_unless_zero(page
))
5511 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5512 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5513 pte_t ptent
, swp_entry_t
*entry
)
5515 struct page
*page
= NULL
;
5516 swp_entry_t ent
= pte_to_swp_entry(ptent
);
5518 if (!(mc
.flags
& MOVE_ANON
))
5522 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5523 * a device and because they are not accessible by CPU they are store
5524 * as special swap entry in the CPU page table.
5526 if (is_device_private_entry(ent
)) {
5527 page
= pfn_swap_entry_to_page(ent
);
5529 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5530 * a refcount of 1 when free (unlike normal page)
5532 if (!page_ref_add_unless(page
, 1, 1))
5537 if (non_swap_entry(ent
))
5541 * Because lookup_swap_cache() updates some statistics counter,
5542 * we call find_get_page() with swapper_space directly.
5544 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
5545 entry
->val
= ent
.val
;
5550 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5551 pte_t ptent
, swp_entry_t
*entry
)
5557 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5558 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5560 if (!vma
->vm_file
) /* anonymous vma */
5562 if (!(mc
.flags
& MOVE_FILE
))
5565 /* page is moved even if it's not RSS of this task(page-faulted). */
5566 /* shmem/tmpfs may report page out on swap: account for that too. */
5567 return find_get_incore_page(vma
->vm_file
->f_mapping
,
5568 linear_page_index(vma
, addr
));
5572 * mem_cgroup_move_account - move account of the page
5574 * @compound: charge the page as compound or small page
5575 * @from: mem_cgroup which the page is moved from.
5576 * @to: mem_cgroup which the page is moved to. @from != @to.
5578 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5580 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5583 static int mem_cgroup_move_account(struct page
*page
,
5585 struct mem_cgroup
*from
,
5586 struct mem_cgroup
*to
)
5588 struct lruvec
*from_vec
, *to_vec
;
5589 struct pglist_data
*pgdat
;
5590 unsigned int nr_pages
= compound
? thp_nr_pages(page
) : 1;
5593 VM_BUG_ON(from
== to
);
5594 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5595 VM_BUG_ON(compound
&& !PageTransHuge(page
));
5598 * Prevent mem_cgroup_migrate() from looking at
5599 * page's memory cgroup of its source page while we change it.
5602 if (!trylock_page(page
))
5606 if (page_memcg(page
) != from
)
5609 pgdat
= page_pgdat(page
);
5610 from_vec
= mem_cgroup_lruvec(from
, pgdat
);
5611 to_vec
= mem_cgroup_lruvec(to
, pgdat
);
5613 lock_page_memcg(page
);
5615 if (PageAnon(page
)) {
5616 if (page_mapped(page
)) {
5617 __mod_lruvec_state(from_vec
, NR_ANON_MAPPED
, -nr_pages
);
5618 __mod_lruvec_state(to_vec
, NR_ANON_MAPPED
, nr_pages
);
5619 if (PageTransHuge(page
)) {
5620 __mod_lruvec_state(from_vec
, NR_ANON_THPS
,
5622 __mod_lruvec_state(to_vec
, NR_ANON_THPS
,
5627 __mod_lruvec_state(from_vec
, NR_FILE_PAGES
, -nr_pages
);
5628 __mod_lruvec_state(to_vec
, NR_FILE_PAGES
, nr_pages
);
5630 if (PageSwapBacked(page
)) {
5631 __mod_lruvec_state(from_vec
, NR_SHMEM
, -nr_pages
);
5632 __mod_lruvec_state(to_vec
, NR_SHMEM
, nr_pages
);
5635 if (page_mapped(page
)) {
5636 __mod_lruvec_state(from_vec
, NR_FILE_MAPPED
, -nr_pages
);
5637 __mod_lruvec_state(to_vec
, NR_FILE_MAPPED
, nr_pages
);
5640 if (PageDirty(page
)) {
5641 struct address_space
*mapping
= page_mapping(page
);
5643 if (mapping_can_writeback(mapping
)) {
5644 __mod_lruvec_state(from_vec
, NR_FILE_DIRTY
,
5646 __mod_lruvec_state(to_vec
, NR_FILE_DIRTY
,
5652 if (PageWriteback(page
)) {
5653 __mod_lruvec_state(from_vec
, NR_WRITEBACK
, -nr_pages
);
5654 __mod_lruvec_state(to_vec
, NR_WRITEBACK
, nr_pages
);
5658 * All state has been migrated, let's switch to the new memcg.
5660 * It is safe to change page's memcg here because the page
5661 * is referenced, charged, isolated, and locked: we can't race
5662 * with (un)charging, migration, LRU putback, or anything else
5663 * that would rely on a stable page's memory cgroup.
5665 * Note that lock_page_memcg is a memcg lock, not a page lock,
5666 * to save space. As soon as we switch page's memory cgroup to a
5667 * new memcg that isn't locked, the above state can change
5668 * concurrently again. Make sure we're truly done with it.
5673 css_put(&from
->css
);
5675 page
->memcg_data
= (unsigned long)to
;
5677 __unlock_page_memcg(from
);
5681 local_irq_disable();
5682 mem_cgroup_charge_statistics(to
, page
, nr_pages
);
5683 memcg_check_events(to
, page
);
5684 mem_cgroup_charge_statistics(from
, page
, -nr_pages
);
5685 memcg_check_events(from
, page
);
5694 * get_mctgt_type - get target type of moving charge
5695 * @vma: the vma the pte to be checked belongs
5696 * @addr: the address corresponding to the pte to be checked
5697 * @ptent: the pte to be checked
5698 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5701 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5702 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5703 * move charge. if @target is not NULL, the page is stored in target->page
5704 * with extra refcnt got(Callers should handle it).
5705 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5706 * target for charge migration. if @target is not NULL, the entry is stored
5708 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5709 * (so ZONE_DEVICE page and thus not on the lru).
5710 * For now we such page is charge like a regular page would be as for all
5711 * intent and purposes it is just special memory taking the place of a
5714 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5716 * Called with pte lock held.
5719 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5720 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5722 struct page
*page
= NULL
;
5723 enum mc_target_type ret
= MC_TARGET_NONE
;
5724 swp_entry_t ent
= { .val
= 0 };
5726 if (pte_present(ptent
))
5727 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5728 else if (is_swap_pte(ptent
))
5729 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
5730 else if (pte_none(ptent
))
5731 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5733 if (!page
&& !ent
.val
)
5737 * Do only loose check w/o serialization.
5738 * mem_cgroup_move_account() checks the page is valid or
5739 * not under LRU exclusion.
5741 if (page_memcg(page
) == mc
.from
) {
5742 ret
= MC_TARGET_PAGE
;
5743 if (is_device_private_page(page
))
5744 ret
= MC_TARGET_DEVICE
;
5746 target
->page
= page
;
5748 if (!ret
|| !target
)
5752 * There is a swap entry and a page doesn't exist or isn't charged.
5753 * But we cannot move a tail-page in a THP.
5755 if (ent
.val
&& !ret
&& (!page
|| !PageTransCompound(page
)) &&
5756 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
5757 ret
= MC_TARGET_SWAP
;
5764 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5766 * We don't consider PMD mapped swapping or file mapped pages because THP does
5767 * not support them for now.
5768 * Caller should make sure that pmd_trans_huge(pmd) is true.
5770 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5771 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5773 struct page
*page
= NULL
;
5774 enum mc_target_type ret
= MC_TARGET_NONE
;
5776 if (unlikely(is_swap_pmd(pmd
))) {
5777 VM_BUG_ON(thp_migration_supported() &&
5778 !is_pmd_migration_entry(pmd
));
5781 page
= pmd_page(pmd
);
5782 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
5783 if (!(mc
.flags
& MOVE_ANON
))
5785 if (page_memcg(page
) == mc
.from
) {
5786 ret
= MC_TARGET_PAGE
;
5789 target
->page
= page
;
5795 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5796 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5798 return MC_TARGET_NONE
;
5802 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5803 unsigned long addr
, unsigned long end
,
5804 struct mm_walk
*walk
)
5806 struct vm_area_struct
*vma
= walk
->vma
;
5810 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5813 * Note their can not be MC_TARGET_DEVICE for now as we do not
5814 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5815 * this might change.
5817 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5818 mc
.precharge
+= HPAGE_PMD_NR
;
5823 if (pmd_trans_unstable(pmd
))
5825 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5826 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5827 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5828 mc
.precharge
++; /* increment precharge temporarily */
5829 pte_unmap_unlock(pte
- 1, ptl
);
5835 static const struct mm_walk_ops precharge_walk_ops
= {
5836 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5839 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5841 unsigned long precharge
;
5844 walk_page_range(mm
, 0, mm
->highest_vm_end
, &precharge_walk_ops
, NULL
);
5845 mmap_read_unlock(mm
);
5847 precharge
= mc
.precharge
;
5853 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5855 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5857 VM_BUG_ON(mc
.moving_task
);
5858 mc
.moving_task
= current
;
5859 return mem_cgroup_do_precharge(precharge
);
5862 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5863 static void __mem_cgroup_clear_mc(void)
5865 struct mem_cgroup
*from
= mc
.from
;
5866 struct mem_cgroup
*to
= mc
.to
;
5868 /* we must uncharge all the leftover precharges from mc.to */
5870 cancel_charge(mc
.to
, mc
.precharge
);
5874 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5875 * we must uncharge here.
5877 if (mc
.moved_charge
) {
5878 cancel_charge(mc
.from
, mc
.moved_charge
);
5879 mc
.moved_charge
= 0;
5881 /* we must fixup refcnts and charges */
5882 if (mc
.moved_swap
) {
5883 /* uncharge swap account from the old cgroup */
5884 if (!mem_cgroup_is_root(mc
.from
))
5885 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
5887 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
5890 * we charged both to->memory and to->memsw, so we
5891 * should uncharge to->memory.
5893 if (!mem_cgroup_is_root(mc
.to
))
5894 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
5898 memcg_oom_recover(from
);
5899 memcg_oom_recover(to
);
5900 wake_up_all(&mc
.waitq
);
5903 static void mem_cgroup_clear_mc(void)
5905 struct mm_struct
*mm
= mc
.mm
;
5908 * we must clear moving_task before waking up waiters at the end of
5911 mc
.moving_task
= NULL
;
5912 __mem_cgroup_clear_mc();
5913 spin_lock(&mc
.lock
);
5917 spin_unlock(&mc
.lock
);
5922 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5924 struct cgroup_subsys_state
*css
;
5925 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
5926 struct mem_cgroup
*from
;
5927 struct task_struct
*leader
, *p
;
5928 struct mm_struct
*mm
;
5929 unsigned long move_flags
;
5932 /* charge immigration isn't supported on the default hierarchy */
5933 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5937 * Multi-process migrations only happen on the default hierarchy
5938 * where charge immigration is not used. Perform charge
5939 * immigration if @tset contains a leader and whine if there are
5943 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
5946 memcg
= mem_cgroup_from_css(css
);
5952 * We are now committed to this value whatever it is. Changes in this
5953 * tunable will only affect upcoming migrations, not the current one.
5954 * So we need to save it, and keep it going.
5956 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
5960 from
= mem_cgroup_from_task(p
);
5962 VM_BUG_ON(from
== memcg
);
5964 mm
= get_task_mm(p
);
5967 /* We move charges only when we move a owner of the mm */
5968 if (mm
->owner
== p
) {
5971 VM_BUG_ON(mc
.precharge
);
5972 VM_BUG_ON(mc
.moved_charge
);
5973 VM_BUG_ON(mc
.moved_swap
);
5975 spin_lock(&mc
.lock
);
5979 mc
.flags
= move_flags
;
5980 spin_unlock(&mc
.lock
);
5981 /* We set mc.moving_task later */
5983 ret
= mem_cgroup_precharge_mc(mm
);
5985 mem_cgroup_clear_mc();
5992 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
5995 mem_cgroup_clear_mc();
5998 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
5999 unsigned long addr
, unsigned long end
,
6000 struct mm_walk
*walk
)
6003 struct vm_area_struct
*vma
= walk
->vma
;
6006 enum mc_target_type target_type
;
6007 union mc_target target
;
6010 ptl
= pmd_trans_huge_lock(pmd
, vma
);
6012 if (mc
.precharge
< HPAGE_PMD_NR
) {
6016 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
6017 if (target_type
== MC_TARGET_PAGE
) {
6019 if (!isolate_lru_page(page
)) {
6020 if (!mem_cgroup_move_account(page
, true,
6022 mc
.precharge
-= HPAGE_PMD_NR
;
6023 mc
.moved_charge
+= HPAGE_PMD_NR
;
6025 putback_lru_page(page
);
6028 } else if (target_type
== MC_TARGET_DEVICE
) {
6030 if (!mem_cgroup_move_account(page
, true,
6032 mc
.precharge
-= HPAGE_PMD_NR
;
6033 mc
.moved_charge
+= HPAGE_PMD_NR
;
6041 if (pmd_trans_unstable(pmd
))
6044 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6045 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
6046 pte_t ptent
= *(pte
++);
6047 bool device
= false;
6053 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
6054 case MC_TARGET_DEVICE
:
6057 case MC_TARGET_PAGE
:
6060 * We can have a part of the split pmd here. Moving it
6061 * can be done but it would be too convoluted so simply
6062 * ignore such a partial THP and keep it in original
6063 * memcg. There should be somebody mapping the head.
6065 if (PageTransCompound(page
))
6067 if (!device
&& isolate_lru_page(page
))
6069 if (!mem_cgroup_move_account(page
, false,
6072 /* we uncharge from mc.from later. */
6076 putback_lru_page(page
);
6077 put
: /* get_mctgt_type() gets the page */
6080 case MC_TARGET_SWAP
:
6082 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
6084 mem_cgroup_id_get_many(mc
.to
, 1);
6085 /* we fixup other refcnts and charges later. */
6093 pte_unmap_unlock(pte
- 1, ptl
);
6098 * We have consumed all precharges we got in can_attach().
6099 * We try charge one by one, but don't do any additional
6100 * charges to mc.to if we have failed in charge once in attach()
6103 ret
= mem_cgroup_do_precharge(1);
6111 static const struct mm_walk_ops charge_walk_ops
= {
6112 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
6115 static void mem_cgroup_move_charge(void)
6117 lru_add_drain_all();
6119 * Signal lock_page_memcg() to take the memcg's move_lock
6120 * while we're moving its pages to another memcg. Then wait
6121 * for already started RCU-only updates to finish.
6123 atomic_inc(&mc
.from
->moving_account
);
6126 if (unlikely(!mmap_read_trylock(mc
.mm
))) {
6128 * Someone who are holding the mmap_lock might be waiting in
6129 * waitq. So we cancel all extra charges, wake up all waiters,
6130 * and retry. Because we cancel precharges, we might not be able
6131 * to move enough charges, but moving charge is a best-effort
6132 * feature anyway, so it wouldn't be a big problem.
6134 __mem_cgroup_clear_mc();
6139 * When we have consumed all precharges and failed in doing
6140 * additional charge, the page walk just aborts.
6142 walk_page_range(mc
.mm
, 0, mc
.mm
->highest_vm_end
, &charge_walk_ops
,
6145 mmap_read_unlock(mc
.mm
);
6146 atomic_dec(&mc
.from
->moving_account
);
6149 static void mem_cgroup_move_task(void)
6152 mem_cgroup_move_charge();
6153 mem_cgroup_clear_mc();
6156 #else /* !CONFIG_MMU */
6157 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
6161 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
6164 static void mem_cgroup_move_task(void)
6169 static int seq_puts_memcg_tunable(struct seq_file
*m
, unsigned long value
)
6171 if (value
== PAGE_COUNTER_MAX
)
6172 seq_puts(m
, "max\n");
6174 seq_printf(m
, "%llu\n", (u64
)value
* PAGE_SIZE
);
6179 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
6182 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6184 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
6187 static int memory_min_show(struct seq_file
*m
, void *v
)
6189 return seq_puts_memcg_tunable(m
,
6190 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.min
));
6193 static ssize_t
memory_min_write(struct kernfs_open_file
*of
,
6194 char *buf
, size_t nbytes
, loff_t off
)
6196 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6200 buf
= strstrip(buf
);
6201 err
= page_counter_memparse(buf
, "max", &min
);
6205 page_counter_set_min(&memcg
->memory
, min
);
6210 static int memory_low_show(struct seq_file
*m
, void *v
)
6212 return seq_puts_memcg_tunable(m
,
6213 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.low
));
6216 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
6217 char *buf
, size_t nbytes
, loff_t off
)
6219 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6223 buf
= strstrip(buf
);
6224 err
= page_counter_memparse(buf
, "max", &low
);
6228 page_counter_set_low(&memcg
->memory
, low
);
6233 static int memory_high_show(struct seq_file
*m
, void *v
)
6235 return seq_puts_memcg_tunable(m
,
6236 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.high
));
6239 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
6240 char *buf
, size_t nbytes
, loff_t off
)
6242 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6243 unsigned int nr_retries
= MAX_RECLAIM_RETRIES
;
6244 bool drained
= false;
6248 buf
= strstrip(buf
);
6249 err
= page_counter_memparse(buf
, "max", &high
);
6253 page_counter_set_high(&memcg
->memory
, high
);
6256 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6257 unsigned long reclaimed
;
6259 if (nr_pages
<= high
)
6262 if (signal_pending(current
))
6266 drain_all_stock(memcg
);
6271 reclaimed
= try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
6274 if (!reclaimed
&& !nr_retries
--)
6278 memcg_wb_domain_size_changed(memcg
);
6282 static int memory_max_show(struct seq_file
*m
, void *v
)
6284 return seq_puts_memcg_tunable(m
,
6285 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.max
));
6288 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
6289 char *buf
, size_t nbytes
, loff_t off
)
6291 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6292 unsigned int nr_reclaims
= MAX_RECLAIM_RETRIES
;
6293 bool drained
= false;
6297 buf
= strstrip(buf
);
6298 err
= page_counter_memparse(buf
, "max", &max
);
6302 xchg(&memcg
->memory
.max
, max
);
6305 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6307 if (nr_pages
<= max
)
6310 if (signal_pending(current
))
6314 drain_all_stock(memcg
);
6320 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
6326 memcg_memory_event(memcg
, MEMCG_OOM
);
6327 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
6331 memcg_wb_domain_size_changed(memcg
);
6335 static void __memory_events_show(struct seq_file
*m
, atomic_long_t
*events
)
6337 seq_printf(m
, "low %lu\n", atomic_long_read(&events
[MEMCG_LOW
]));
6338 seq_printf(m
, "high %lu\n", atomic_long_read(&events
[MEMCG_HIGH
]));
6339 seq_printf(m
, "max %lu\n", atomic_long_read(&events
[MEMCG_MAX
]));
6340 seq_printf(m
, "oom %lu\n", atomic_long_read(&events
[MEMCG_OOM
]));
6341 seq_printf(m
, "oom_kill %lu\n",
6342 atomic_long_read(&events
[MEMCG_OOM_KILL
]));
6345 static int memory_events_show(struct seq_file
*m
, void *v
)
6347 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6349 __memory_events_show(m
, memcg
->memory_events
);
6353 static int memory_events_local_show(struct seq_file
*m
, void *v
)
6355 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6357 __memory_events_show(m
, memcg
->memory_events_local
);
6361 static int memory_stat_show(struct seq_file
*m
, void *v
)
6363 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6366 buf
= memory_stat_format(memcg
);
6375 static inline unsigned long lruvec_page_state_output(struct lruvec
*lruvec
,
6378 return lruvec_page_state(lruvec
, item
) * memcg_page_state_unit(item
);
6381 static int memory_numa_stat_show(struct seq_file
*m
, void *v
)
6384 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6386 cgroup_rstat_flush(memcg
->css
.cgroup
);
6388 for (i
= 0; i
< ARRAY_SIZE(memory_stats
); i
++) {
6391 if (memory_stats
[i
].idx
>= NR_VM_NODE_STAT_ITEMS
)
6394 seq_printf(m
, "%s", memory_stats
[i
].name
);
6395 for_each_node_state(nid
, N_MEMORY
) {
6397 struct lruvec
*lruvec
;
6399 lruvec
= mem_cgroup_lruvec(memcg
, NODE_DATA(nid
));
6400 size
= lruvec_page_state_output(lruvec
,
6401 memory_stats
[i
].idx
);
6402 seq_printf(m
, " N%d=%llu", nid
, size
);
6411 static int memory_oom_group_show(struct seq_file
*m
, void *v
)
6413 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6415 seq_printf(m
, "%d\n", memcg
->oom_group
);
6420 static ssize_t
memory_oom_group_write(struct kernfs_open_file
*of
,
6421 char *buf
, size_t nbytes
, loff_t off
)
6423 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6426 buf
= strstrip(buf
);
6430 ret
= kstrtoint(buf
, 0, &oom_group
);
6434 if (oom_group
!= 0 && oom_group
!= 1)
6437 memcg
->oom_group
= oom_group
;
6442 static struct cftype memory_files
[] = {
6445 .flags
= CFTYPE_NOT_ON_ROOT
,
6446 .read_u64
= memory_current_read
,
6450 .flags
= CFTYPE_NOT_ON_ROOT
,
6451 .seq_show
= memory_min_show
,
6452 .write
= memory_min_write
,
6456 .flags
= CFTYPE_NOT_ON_ROOT
,
6457 .seq_show
= memory_low_show
,
6458 .write
= memory_low_write
,
6462 .flags
= CFTYPE_NOT_ON_ROOT
,
6463 .seq_show
= memory_high_show
,
6464 .write
= memory_high_write
,
6468 .flags
= CFTYPE_NOT_ON_ROOT
,
6469 .seq_show
= memory_max_show
,
6470 .write
= memory_max_write
,
6474 .flags
= CFTYPE_NOT_ON_ROOT
,
6475 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
6476 .seq_show
= memory_events_show
,
6479 .name
= "events.local",
6480 .flags
= CFTYPE_NOT_ON_ROOT
,
6481 .file_offset
= offsetof(struct mem_cgroup
, events_local_file
),
6482 .seq_show
= memory_events_local_show
,
6486 .seq_show
= memory_stat_show
,
6490 .name
= "numa_stat",
6491 .seq_show
= memory_numa_stat_show
,
6495 .name
= "oom.group",
6496 .flags
= CFTYPE_NOT_ON_ROOT
| CFTYPE_NS_DELEGATABLE
,
6497 .seq_show
= memory_oom_group_show
,
6498 .write
= memory_oom_group_write
,
6503 struct cgroup_subsys memory_cgrp_subsys
= {
6504 .css_alloc
= mem_cgroup_css_alloc
,
6505 .css_online
= mem_cgroup_css_online
,
6506 .css_offline
= mem_cgroup_css_offline
,
6507 .css_released
= mem_cgroup_css_released
,
6508 .css_free
= mem_cgroup_css_free
,
6509 .css_reset
= mem_cgroup_css_reset
,
6510 .css_rstat_flush
= mem_cgroup_css_rstat_flush
,
6511 .can_attach
= mem_cgroup_can_attach
,
6512 .cancel_attach
= mem_cgroup_cancel_attach
,
6513 .post_attach
= mem_cgroup_move_task
,
6514 .dfl_cftypes
= memory_files
,
6515 .legacy_cftypes
= mem_cgroup_legacy_files
,
6520 * This function calculates an individual cgroup's effective
6521 * protection which is derived from its own memory.min/low, its
6522 * parent's and siblings' settings, as well as the actual memory
6523 * distribution in the tree.
6525 * The following rules apply to the effective protection values:
6527 * 1. At the first level of reclaim, effective protection is equal to
6528 * the declared protection in memory.min and memory.low.
6530 * 2. To enable safe delegation of the protection configuration, at
6531 * subsequent levels the effective protection is capped to the
6532 * parent's effective protection.
6534 * 3. To make complex and dynamic subtrees easier to configure, the
6535 * user is allowed to overcommit the declared protection at a given
6536 * level. If that is the case, the parent's effective protection is
6537 * distributed to the children in proportion to how much protection
6538 * they have declared and how much of it they are utilizing.
6540 * This makes distribution proportional, but also work-conserving:
6541 * if one cgroup claims much more protection than it uses memory,
6542 * the unused remainder is available to its siblings.
6544 * 4. Conversely, when the declared protection is undercommitted at a
6545 * given level, the distribution of the larger parental protection
6546 * budget is NOT proportional. A cgroup's protection from a sibling
6547 * is capped to its own memory.min/low setting.
6549 * 5. However, to allow protecting recursive subtrees from each other
6550 * without having to declare each individual cgroup's fixed share
6551 * of the ancestor's claim to protection, any unutilized -
6552 * "floating" - protection from up the tree is distributed in
6553 * proportion to each cgroup's *usage*. This makes the protection
6554 * neutral wrt sibling cgroups and lets them compete freely over
6555 * the shared parental protection budget, but it protects the
6556 * subtree as a whole from neighboring subtrees.
6558 * Note that 4. and 5. are not in conflict: 4. is about protecting
6559 * against immediate siblings whereas 5. is about protecting against
6560 * neighboring subtrees.
6562 static unsigned long effective_protection(unsigned long usage
,
6563 unsigned long parent_usage
,
6564 unsigned long setting
,
6565 unsigned long parent_effective
,
6566 unsigned long siblings_protected
)
6568 unsigned long protected;
6571 protected = min(usage
, setting
);
6573 * If all cgroups at this level combined claim and use more
6574 * protection then what the parent affords them, distribute
6575 * shares in proportion to utilization.
6577 * We are using actual utilization rather than the statically
6578 * claimed protection in order to be work-conserving: claimed
6579 * but unused protection is available to siblings that would
6580 * otherwise get a smaller chunk than what they claimed.
6582 if (siblings_protected
> parent_effective
)
6583 return protected * parent_effective
/ siblings_protected
;
6586 * Ok, utilized protection of all children is within what the
6587 * parent affords them, so we know whatever this child claims
6588 * and utilizes is effectively protected.
6590 * If there is unprotected usage beyond this value, reclaim
6591 * will apply pressure in proportion to that amount.
6593 * If there is unutilized protection, the cgroup will be fully
6594 * shielded from reclaim, but we do return a smaller value for
6595 * protection than what the group could enjoy in theory. This
6596 * is okay. With the overcommit distribution above, effective
6597 * protection is always dependent on how memory is actually
6598 * consumed among the siblings anyway.
6603 * If the children aren't claiming (all of) the protection
6604 * afforded to them by the parent, distribute the remainder in
6605 * proportion to the (unprotected) memory of each cgroup. That
6606 * way, cgroups that aren't explicitly prioritized wrt each
6607 * other compete freely over the allowance, but they are
6608 * collectively protected from neighboring trees.
6610 * We're using unprotected memory for the weight so that if
6611 * some cgroups DO claim explicit protection, we don't protect
6612 * the same bytes twice.
6614 * Check both usage and parent_usage against the respective
6615 * protected values. One should imply the other, but they
6616 * aren't read atomically - make sure the division is sane.
6618 if (!(cgrp_dfl_root
.flags
& CGRP_ROOT_MEMORY_RECURSIVE_PROT
))
6620 if (parent_effective
> siblings_protected
&&
6621 parent_usage
> siblings_protected
&&
6622 usage
> protected) {
6623 unsigned long unclaimed
;
6625 unclaimed
= parent_effective
- siblings_protected
;
6626 unclaimed
*= usage
- protected;
6627 unclaimed
/= parent_usage
- siblings_protected
;
6636 * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
6637 * @root: the top ancestor of the sub-tree being checked
6638 * @memcg: the memory cgroup to check
6640 * WARNING: This function is not stateless! It can only be used as part
6641 * of a top-down tree iteration, not for isolated queries.
6643 void mem_cgroup_calculate_protection(struct mem_cgroup
*root
,
6644 struct mem_cgroup
*memcg
)
6646 unsigned long usage
, parent_usage
;
6647 struct mem_cgroup
*parent
;
6649 if (mem_cgroup_disabled())
6653 root
= root_mem_cgroup
;
6656 * Effective values of the reclaim targets are ignored so they
6657 * can be stale. Have a look at mem_cgroup_protection for more
6659 * TODO: calculation should be more robust so that we do not need
6660 * that special casing.
6665 usage
= page_counter_read(&memcg
->memory
);
6669 parent
= parent_mem_cgroup(memcg
);
6670 /* No parent means a non-hierarchical mode on v1 memcg */
6674 if (parent
== root
) {
6675 memcg
->memory
.emin
= READ_ONCE(memcg
->memory
.min
);
6676 memcg
->memory
.elow
= READ_ONCE(memcg
->memory
.low
);
6680 parent_usage
= page_counter_read(&parent
->memory
);
6682 WRITE_ONCE(memcg
->memory
.emin
, effective_protection(usage
, parent_usage
,
6683 READ_ONCE(memcg
->memory
.min
),
6684 READ_ONCE(parent
->memory
.emin
),
6685 atomic_long_read(&parent
->memory
.children_min_usage
)));
6687 WRITE_ONCE(memcg
->memory
.elow
, effective_protection(usage
, parent_usage
,
6688 READ_ONCE(memcg
->memory
.low
),
6689 READ_ONCE(parent
->memory
.elow
),
6690 atomic_long_read(&parent
->memory
.children_low_usage
)));
6693 static int charge_memcg(struct page
*page
, struct mem_cgroup
*memcg
, gfp_t gfp
)
6695 unsigned int nr_pages
= thp_nr_pages(page
);
6698 ret
= try_charge(memcg
, gfp
, nr_pages
);
6702 css_get(&memcg
->css
);
6703 commit_charge(page
, memcg
);
6705 local_irq_disable();
6706 mem_cgroup_charge_statistics(memcg
, page
, nr_pages
);
6707 memcg_check_events(memcg
, page
);
6714 * __mem_cgroup_charge - charge a newly allocated page to a cgroup
6715 * @page: page to charge
6716 * @mm: mm context of the victim
6717 * @gfp_mask: reclaim mode
6719 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6720 * pages according to @gfp_mask if necessary. if @mm is NULL, try to
6721 * charge to the active memcg.
6723 * Do not use this for pages allocated for swapin.
6725 * Returns 0 on success. Otherwise, an error code is returned.
6727 int __mem_cgroup_charge(struct page
*page
, struct mm_struct
*mm
,
6730 struct mem_cgroup
*memcg
;
6733 memcg
= get_mem_cgroup_from_mm(mm
);
6734 ret
= charge_memcg(page
, memcg
, gfp_mask
);
6735 css_put(&memcg
->css
);
6741 * mem_cgroup_swapin_charge_page - charge a newly allocated page for swapin
6742 * @page: page to charge
6743 * @mm: mm context of the victim
6744 * @gfp: reclaim mode
6745 * @entry: swap entry for which the page is allocated
6747 * This function charges a page allocated for swapin. Please call this before
6748 * adding the page to the swapcache.
6750 * Returns 0 on success. Otherwise, an error code is returned.
6752 int mem_cgroup_swapin_charge_page(struct page
*page
, struct mm_struct
*mm
,
6753 gfp_t gfp
, swp_entry_t entry
)
6755 struct mem_cgroup
*memcg
;
6759 if (mem_cgroup_disabled())
6762 id
= lookup_swap_cgroup_id(entry
);
6764 memcg
= mem_cgroup_from_id(id
);
6765 if (!memcg
|| !css_tryget_online(&memcg
->css
))
6766 memcg
= get_mem_cgroup_from_mm(mm
);
6769 ret
= charge_memcg(page
, memcg
, gfp
);
6771 css_put(&memcg
->css
);
6776 * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
6777 * @entry: swap entry for which the page is charged
6779 * Call this function after successfully adding the charged page to swapcache.
6781 * Note: This function assumes the page for which swap slot is being uncharged
6784 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry
)
6787 * Cgroup1's unified memory+swap counter has been charged with the
6788 * new swapcache page, finish the transfer by uncharging the swap
6789 * slot. The swap slot would also get uncharged when it dies, but
6790 * it can stick around indefinitely and we'd count the page twice
6793 * Cgroup2 has separate resource counters for memory and swap,
6794 * so this is a non-issue here. Memory and swap charge lifetimes
6795 * correspond 1:1 to page and swap slot lifetimes: we charge the
6796 * page to memory here, and uncharge swap when the slot is freed.
6798 if (!mem_cgroup_disabled() && do_memsw_account()) {
6800 * The swap entry might not get freed for a long time,
6801 * let's not wait for it. The page already received a
6802 * memory+swap charge, drop the swap entry duplicate.
6804 mem_cgroup_uncharge_swap(entry
, 1);
6808 struct uncharge_gather
{
6809 struct mem_cgroup
*memcg
;
6810 unsigned long nr_memory
;
6811 unsigned long pgpgout
;
6812 unsigned long nr_kmem
;
6813 struct page
*dummy_page
;
6816 static inline void uncharge_gather_clear(struct uncharge_gather
*ug
)
6818 memset(ug
, 0, sizeof(*ug
));
6821 static void uncharge_batch(const struct uncharge_gather
*ug
)
6823 unsigned long flags
;
6825 if (ug
->nr_memory
) {
6826 page_counter_uncharge(&ug
->memcg
->memory
, ug
->nr_memory
);
6827 if (do_memsw_account())
6828 page_counter_uncharge(&ug
->memcg
->memsw
, ug
->nr_memory
);
6829 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && ug
->nr_kmem
)
6830 page_counter_uncharge(&ug
->memcg
->kmem
, ug
->nr_kmem
);
6831 memcg_oom_recover(ug
->memcg
);
6834 local_irq_save(flags
);
6835 __count_memcg_events(ug
->memcg
, PGPGOUT
, ug
->pgpgout
);
6836 __this_cpu_add(ug
->memcg
->vmstats_percpu
->nr_page_events
, ug
->nr_memory
);
6837 memcg_check_events(ug
->memcg
, ug
->dummy_page
);
6838 local_irq_restore(flags
);
6840 /* drop reference from uncharge_page */
6841 css_put(&ug
->memcg
->css
);
6844 static void uncharge_page(struct page
*page
, struct uncharge_gather
*ug
)
6846 unsigned long nr_pages
;
6847 struct mem_cgroup
*memcg
;
6848 struct obj_cgroup
*objcg
;
6849 bool use_objcg
= PageMemcgKmem(page
);
6851 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6854 * Nobody should be changing or seriously looking at
6855 * page memcg or objcg at this point, we have fully
6856 * exclusive access to the page.
6859 objcg
= __page_objcg(page
);
6861 * This get matches the put at the end of the function and
6862 * kmem pages do not hold memcg references anymore.
6864 memcg
= get_mem_cgroup_from_objcg(objcg
);
6866 memcg
= __page_memcg(page
);
6872 if (ug
->memcg
!= memcg
) {
6875 uncharge_gather_clear(ug
);
6878 ug
->dummy_page
= page
;
6880 /* pairs with css_put in uncharge_batch */
6881 css_get(&memcg
->css
);
6884 nr_pages
= compound_nr(page
);
6887 ug
->nr_memory
+= nr_pages
;
6888 ug
->nr_kmem
+= nr_pages
;
6890 page
->memcg_data
= 0;
6891 obj_cgroup_put(objcg
);
6893 /* LRU pages aren't accounted at the root level */
6894 if (!mem_cgroup_is_root(memcg
))
6895 ug
->nr_memory
+= nr_pages
;
6898 page
->memcg_data
= 0;
6901 css_put(&memcg
->css
);
6905 * __mem_cgroup_uncharge - uncharge a page
6906 * @page: page to uncharge
6908 * Uncharge a page previously charged with __mem_cgroup_charge().
6910 void __mem_cgroup_uncharge(struct page
*page
)
6912 struct uncharge_gather ug
;
6914 /* Don't touch page->lru of any random page, pre-check: */
6915 if (!page_memcg(page
))
6918 uncharge_gather_clear(&ug
);
6919 uncharge_page(page
, &ug
);
6920 uncharge_batch(&ug
);
6924 * __mem_cgroup_uncharge_list - uncharge a list of page
6925 * @page_list: list of pages to uncharge
6927 * Uncharge a list of pages previously charged with
6928 * __mem_cgroup_charge().
6930 void __mem_cgroup_uncharge_list(struct list_head
*page_list
)
6932 struct uncharge_gather ug
;
6935 uncharge_gather_clear(&ug
);
6936 list_for_each_entry(page
, page_list
, lru
)
6937 uncharge_page(page
, &ug
);
6939 uncharge_batch(&ug
);
6943 * mem_cgroup_migrate - charge a page's replacement
6944 * @oldpage: currently circulating page
6945 * @newpage: replacement page
6947 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6948 * be uncharged upon free.
6950 * Both pages must be locked, @newpage->mapping must be set up.
6952 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
6954 struct mem_cgroup
*memcg
;
6955 unsigned int nr_pages
;
6956 unsigned long flags
;
6958 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
6959 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
6960 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
6961 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
6964 if (mem_cgroup_disabled())
6967 /* Page cache replacement: new page already charged? */
6968 if (page_memcg(newpage
))
6971 memcg
= page_memcg(oldpage
);
6972 VM_WARN_ON_ONCE_PAGE(!memcg
, oldpage
);
6976 /* Force-charge the new page. The old one will be freed soon */
6977 nr_pages
= thp_nr_pages(newpage
);
6979 if (!mem_cgroup_is_root(memcg
)) {
6980 page_counter_charge(&memcg
->memory
, nr_pages
);
6981 if (do_memsw_account())
6982 page_counter_charge(&memcg
->memsw
, nr_pages
);
6985 css_get(&memcg
->css
);
6986 commit_charge(newpage
, memcg
);
6988 local_irq_save(flags
);
6989 mem_cgroup_charge_statistics(memcg
, newpage
, nr_pages
);
6990 memcg_check_events(memcg
, newpage
);
6991 local_irq_restore(flags
);
6994 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
6995 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
6997 void mem_cgroup_sk_alloc(struct sock
*sk
)
6999 struct mem_cgroup
*memcg
;
7001 if (!mem_cgroup_sockets_enabled
)
7004 /* Do not associate the sock with unrelated interrupted task's memcg. */
7009 memcg
= mem_cgroup_from_task(current
);
7010 if (memcg
== root_mem_cgroup
)
7012 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
7014 if (css_tryget(&memcg
->css
))
7015 sk
->sk_memcg
= memcg
;
7020 void mem_cgroup_sk_free(struct sock
*sk
)
7023 css_put(&sk
->sk_memcg
->css
);
7027 * mem_cgroup_charge_skmem - charge socket memory
7028 * @memcg: memcg to charge
7029 * @nr_pages: number of pages to charge
7030 * @gfp_mask: reclaim mode
7032 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
7033 * @memcg's configured limit, %false if it doesn't.
7035 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
,
7038 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
7039 struct page_counter
*fail
;
7041 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
7042 memcg
->tcpmem_pressure
= 0;
7045 memcg
->tcpmem_pressure
= 1;
7046 if (gfp_mask
& __GFP_NOFAIL
) {
7047 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
7053 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0) {
7054 mod_memcg_state(memcg
, MEMCG_SOCK
, nr_pages
);
7062 * mem_cgroup_uncharge_skmem - uncharge socket memory
7063 * @memcg: memcg to uncharge
7064 * @nr_pages: number of pages to uncharge
7066 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
7068 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
7069 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
7073 mod_memcg_state(memcg
, MEMCG_SOCK
, -nr_pages
);
7075 refill_stock(memcg
, nr_pages
);
7078 static int __init
cgroup_memory(char *s
)
7082 while ((token
= strsep(&s
, ",")) != NULL
) {
7085 if (!strcmp(token
, "nosocket"))
7086 cgroup_memory_nosocket
= true;
7087 if (!strcmp(token
, "nokmem"))
7088 cgroup_memory_nokmem
= true;
7092 __setup("cgroup.memory=", cgroup_memory
);
7095 * subsys_initcall() for memory controller.
7097 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
7098 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
7099 * basically everything that doesn't depend on a specific mem_cgroup structure
7100 * should be initialized from here.
7102 static int __init
mem_cgroup_init(void)
7107 * Currently s32 type (can refer to struct batched_lruvec_stat) is
7108 * used for per-memcg-per-cpu caching of per-node statistics. In order
7109 * to work fine, we should make sure that the overfill threshold can't
7110 * exceed S32_MAX / PAGE_SIZE.
7112 BUILD_BUG_ON(MEMCG_CHARGE_BATCH
> S32_MAX
/ PAGE_SIZE
);
7114 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
7115 memcg_hotplug_cpu_dead
);
7117 for_each_possible_cpu(cpu
)
7118 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
7121 for_each_node(node
) {
7122 struct mem_cgroup_tree_per_node
*rtpn
;
7124 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
7125 node_online(node
) ? node
: NUMA_NO_NODE
);
7127 rtpn
->rb_root
= RB_ROOT
;
7128 rtpn
->rb_rightmost
= NULL
;
7129 spin_lock_init(&rtpn
->lock
);
7130 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
7135 subsys_initcall(mem_cgroup_init
);
7137 #ifdef CONFIG_MEMCG_SWAP
7138 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
7140 while (!refcount_inc_not_zero(&memcg
->id
.ref
)) {
7142 * The root cgroup cannot be destroyed, so it's refcount must
7145 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
7149 memcg
= parent_mem_cgroup(memcg
);
7151 memcg
= root_mem_cgroup
;
7157 * mem_cgroup_swapout - transfer a memsw charge to swap
7158 * @page: page whose memsw charge to transfer
7159 * @entry: swap entry to move the charge to
7161 * Transfer the memsw charge of @page to @entry.
7163 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
7165 struct mem_cgroup
*memcg
, *swap_memcg
;
7166 unsigned int nr_entries
;
7167 unsigned short oldid
;
7169 VM_BUG_ON_PAGE(PageLRU(page
), page
);
7170 VM_BUG_ON_PAGE(page_count(page
), page
);
7172 if (mem_cgroup_disabled())
7175 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7178 memcg
= page_memcg(page
);
7180 VM_WARN_ON_ONCE_PAGE(!memcg
, page
);
7185 * In case the memcg owning these pages has been offlined and doesn't
7186 * have an ID allocated to it anymore, charge the closest online
7187 * ancestor for the swap instead and transfer the memory+swap charge.
7189 swap_memcg
= mem_cgroup_id_get_online(memcg
);
7190 nr_entries
= thp_nr_pages(page
);
7191 /* Get references for the tail pages, too */
7193 mem_cgroup_id_get_many(swap_memcg
, nr_entries
- 1);
7194 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
),
7196 VM_BUG_ON_PAGE(oldid
, page
);
7197 mod_memcg_state(swap_memcg
, MEMCG_SWAP
, nr_entries
);
7199 page
->memcg_data
= 0;
7201 if (!mem_cgroup_is_root(memcg
))
7202 page_counter_uncharge(&memcg
->memory
, nr_entries
);
7204 if (!cgroup_memory_noswap
&& memcg
!= swap_memcg
) {
7205 if (!mem_cgroup_is_root(swap_memcg
))
7206 page_counter_charge(&swap_memcg
->memsw
, nr_entries
);
7207 page_counter_uncharge(&memcg
->memsw
, nr_entries
);
7211 * Interrupts should be disabled here because the caller holds the
7212 * i_pages lock which is taken with interrupts-off. It is
7213 * important here to have the interrupts disabled because it is the
7214 * only synchronisation we have for updating the per-CPU variables.
7216 VM_BUG_ON(!irqs_disabled());
7217 mem_cgroup_charge_statistics(memcg
, page
, -nr_entries
);
7218 memcg_check_events(memcg
, page
);
7220 css_put(&memcg
->css
);
7224 * __mem_cgroup_try_charge_swap - try charging swap space for a page
7225 * @page: page being added to swap
7226 * @entry: swap entry to charge
7228 * Try to charge @page's memcg for the swap space at @entry.
7230 * Returns 0 on success, -ENOMEM on failure.
7232 int __mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
7234 unsigned int nr_pages
= thp_nr_pages(page
);
7235 struct page_counter
*counter
;
7236 struct mem_cgroup
*memcg
;
7237 unsigned short oldid
;
7239 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7242 memcg
= page_memcg(page
);
7244 VM_WARN_ON_ONCE_PAGE(!memcg
, page
);
7249 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7253 memcg
= mem_cgroup_id_get_online(memcg
);
7255 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
) &&
7256 !page_counter_try_charge(&memcg
->swap
, nr_pages
, &counter
)) {
7257 memcg_memory_event(memcg
, MEMCG_SWAP_MAX
);
7258 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7259 mem_cgroup_id_put(memcg
);
7263 /* Get references for the tail pages, too */
7265 mem_cgroup_id_get_many(memcg
, nr_pages
- 1);
7266 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
), nr_pages
);
7267 VM_BUG_ON_PAGE(oldid
, page
);
7268 mod_memcg_state(memcg
, MEMCG_SWAP
, nr_pages
);
7274 * __mem_cgroup_uncharge_swap - uncharge swap space
7275 * @entry: swap entry to uncharge
7276 * @nr_pages: the amount of swap space to uncharge
7278 void __mem_cgroup_uncharge_swap(swp_entry_t entry
, unsigned int nr_pages
)
7280 struct mem_cgroup
*memcg
;
7283 id
= swap_cgroup_record(entry
, 0, nr_pages
);
7285 memcg
= mem_cgroup_from_id(id
);
7287 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
)) {
7288 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7289 page_counter_uncharge(&memcg
->swap
, nr_pages
);
7291 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
7293 mod_memcg_state(memcg
, MEMCG_SWAP
, -nr_pages
);
7294 mem_cgroup_id_put_many(memcg
, nr_pages
);
7299 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
7301 long nr_swap_pages
= get_nr_swap_pages();
7303 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7304 return nr_swap_pages
;
7305 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
7306 nr_swap_pages
= min_t(long, nr_swap_pages
,
7307 READ_ONCE(memcg
->swap
.max
) -
7308 page_counter_read(&memcg
->swap
));
7309 return nr_swap_pages
;
7312 bool mem_cgroup_swap_full(struct page
*page
)
7314 struct mem_cgroup
*memcg
;
7316 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
7320 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7323 memcg
= page_memcg(page
);
7327 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
)) {
7328 unsigned long usage
= page_counter_read(&memcg
->swap
);
7330 if (usage
* 2 >= READ_ONCE(memcg
->swap
.high
) ||
7331 usage
* 2 >= READ_ONCE(memcg
->swap
.max
))
7338 static int __init
setup_swap_account(char *s
)
7340 if (!strcmp(s
, "1"))
7341 cgroup_memory_noswap
= false;
7342 else if (!strcmp(s
, "0"))
7343 cgroup_memory_noswap
= true;
7346 __setup("swapaccount=", setup_swap_account
);
7348 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
7351 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7353 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
7356 static int swap_high_show(struct seq_file
*m
, void *v
)
7358 return seq_puts_memcg_tunable(m
,
7359 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.high
));
7362 static ssize_t
swap_high_write(struct kernfs_open_file
*of
,
7363 char *buf
, size_t nbytes
, loff_t off
)
7365 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7369 buf
= strstrip(buf
);
7370 err
= page_counter_memparse(buf
, "max", &high
);
7374 page_counter_set_high(&memcg
->swap
, high
);
7379 static int swap_max_show(struct seq_file
*m
, void *v
)
7381 return seq_puts_memcg_tunable(m
,
7382 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.max
));
7385 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
7386 char *buf
, size_t nbytes
, loff_t off
)
7388 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7392 buf
= strstrip(buf
);
7393 err
= page_counter_memparse(buf
, "max", &max
);
7397 xchg(&memcg
->swap
.max
, max
);
7402 static int swap_events_show(struct seq_file
*m
, void *v
)
7404 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
7406 seq_printf(m
, "high %lu\n",
7407 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_HIGH
]));
7408 seq_printf(m
, "max %lu\n",
7409 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_MAX
]));
7410 seq_printf(m
, "fail %lu\n",
7411 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_FAIL
]));
7416 static struct cftype swap_files
[] = {
7418 .name
= "swap.current",
7419 .flags
= CFTYPE_NOT_ON_ROOT
,
7420 .read_u64
= swap_current_read
,
7423 .name
= "swap.high",
7424 .flags
= CFTYPE_NOT_ON_ROOT
,
7425 .seq_show
= swap_high_show
,
7426 .write
= swap_high_write
,
7430 .flags
= CFTYPE_NOT_ON_ROOT
,
7431 .seq_show
= swap_max_show
,
7432 .write
= swap_max_write
,
7435 .name
= "swap.events",
7436 .flags
= CFTYPE_NOT_ON_ROOT
,
7437 .file_offset
= offsetof(struct mem_cgroup
, swap_events_file
),
7438 .seq_show
= swap_events_show
,
7443 static struct cftype memsw_files
[] = {
7445 .name
= "memsw.usage_in_bytes",
7446 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
7447 .read_u64
= mem_cgroup_read_u64
,
7450 .name
= "memsw.max_usage_in_bytes",
7451 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
7452 .write
= mem_cgroup_reset
,
7453 .read_u64
= mem_cgroup_read_u64
,
7456 .name
= "memsw.limit_in_bytes",
7457 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
7458 .write
= mem_cgroup_write
,
7459 .read_u64
= mem_cgroup_read_u64
,
7462 .name
= "memsw.failcnt",
7463 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
7464 .write
= mem_cgroup_reset
,
7465 .read_u64
= mem_cgroup_read_u64
,
7467 { }, /* terminate */
7471 * If mem_cgroup_swap_init() is implemented as a subsys_initcall()
7472 * instead of a core_initcall(), this could mean cgroup_memory_noswap still
7473 * remains set to false even when memcg is disabled via "cgroup_disable=memory"
7474 * boot parameter. This may result in premature OOPS inside
7475 * mem_cgroup_get_nr_swap_pages() function in corner cases.
7477 static int __init
mem_cgroup_swap_init(void)
7479 /* No memory control -> no swap control */
7480 if (mem_cgroup_disabled())
7481 cgroup_memory_noswap
= true;
7483 if (cgroup_memory_noswap
)
7486 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
, swap_files
));
7487 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
, memsw_files
));
7491 core_initcall(mem_cgroup_swap_init
);
7493 #endif /* CONFIG_MEMCG_SWAP */