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 #define THRESHOLDS_EVENTS_TARGET 128
107 #define SOFTLIMIT_EVENTS_TARGET 1024
110 * Cgroups above their limits are maintained in a RB-Tree, independent of
111 * their hierarchy representation
114 struct mem_cgroup_tree_per_node
{
115 struct rb_root rb_root
;
116 struct rb_node
*rb_rightmost
;
120 struct mem_cgroup_tree
{
121 struct mem_cgroup_tree_per_node
*rb_tree_per_node
[MAX_NUMNODES
];
124 static struct mem_cgroup_tree soft_limit_tree __read_mostly
;
127 struct mem_cgroup_eventfd_list
{
128 struct list_head list
;
129 struct eventfd_ctx
*eventfd
;
133 * cgroup_event represents events which userspace want to receive.
135 struct mem_cgroup_event
{
137 * memcg which the event belongs to.
139 struct mem_cgroup
*memcg
;
141 * eventfd to signal userspace about the event.
143 struct eventfd_ctx
*eventfd
;
145 * Each of these stored in a list by the cgroup.
147 struct list_head list
;
149 * register_event() callback will be used to add new userspace
150 * waiter for changes related to this event. Use eventfd_signal()
151 * on eventfd to send notification to userspace.
153 int (*register_event
)(struct mem_cgroup
*memcg
,
154 struct eventfd_ctx
*eventfd
, const char *args
);
156 * unregister_event() callback will be called when userspace closes
157 * the eventfd or on cgroup removing. This callback must be set,
158 * if you want provide notification functionality.
160 void (*unregister_event
)(struct mem_cgroup
*memcg
,
161 struct eventfd_ctx
*eventfd
);
163 * All fields below needed to unregister event when
164 * userspace closes eventfd.
167 wait_queue_head_t
*wqh
;
168 wait_queue_entry_t wait
;
169 struct work_struct remove
;
172 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
);
173 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
);
175 /* Stuffs for move charges at task migration. */
177 * Types of charges to be moved.
179 #define MOVE_ANON 0x1U
180 #define MOVE_FILE 0x2U
181 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
183 /* "mc" and its members are protected by cgroup_mutex */
184 static struct move_charge_struct
{
185 spinlock_t lock
; /* for from, to */
186 struct mm_struct
*mm
;
187 struct mem_cgroup
*from
;
188 struct mem_cgroup
*to
;
190 unsigned long precharge
;
191 unsigned long moved_charge
;
192 unsigned long moved_swap
;
193 struct task_struct
*moving_task
; /* a task moving charges */
194 wait_queue_head_t waitq
; /* a waitq for other context */
196 .lock
= __SPIN_LOCK_UNLOCKED(mc
.lock
),
197 .waitq
= __WAIT_QUEUE_HEAD_INITIALIZER(mc
.waitq
),
201 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
202 * limit reclaim to prevent infinite loops, if they ever occur.
204 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
205 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
207 /* for encoding cft->private value on file */
216 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
217 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
218 #define MEMFILE_ATTR(val) ((val) & 0xffff)
219 /* Used for OOM notifier */
220 #define OOM_CONTROL (0)
223 * Iteration constructs for visiting all cgroups (under a tree). If
224 * loops are exited prematurely (break), mem_cgroup_iter_break() must
225 * be used for reference counting.
227 #define for_each_mem_cgroup_tree(iter, root) \
228 for (iter = mem_cgroup_iter(root, NULL, NULL); \
230 iter = mem_cgroup_iter(root, iter, NULL))
232 #define for_each_mem_cgroup(iter) \
233 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
235 iter = mem_cgroup_iter(NULL, iter, NULL))
237 static inline bool should_force_charge(void)
239 return tsk_is_oom_victim(current
) || fatal_signal_pending(current
) ||
240 (current
->flags
& PF_EXITING
);
243 /* Some nice accessors for the vmpressure. */
244 struct vmpressure
*memcg_to_vmpressure(struct mem_cgroup
*memcg
)
247 memcg
= root_mem_cgroup
;
248 return &memcg
->vmpressure
;
251 struct cgroup_subsys_state
*vmpressure_to_css(struct vmpressure
*vmpr
)
253 return &container_of(vmpr
, struct mem_cgroup
, vmpressure
)->css
;
256 #ifdef CONFIG_MEMCG_KMEM
257 extern spinlock_t css_set_lock
;
259 bool mem_cgroup_kmem_disabled(void)
261 return cgroup_memory_nokmem
;
264 static void obj_cgroup_uncharge_pages(struct obj_cgroup
*objcg
,
265 unsigned int nr_pages
);
267 static void obj_cgroup_release(struct percpu_ref
*ref
)
269 struct obj_cgroup
*objcg
= container_of(ref
, struct obj_cgroup
, refcnt
);
270 unsigned int nr_bytes
;
271 unsigned int nr_pages
;
275 * At this point all allocated objects are freed, and
276 * objcg->nr_charged_bytes can't have an arbitrary byte value.
277 * However, it can be PAGE_SIZE or (x * PAGE_SIZE).
279 * The following sequence can lead to it:
280 * 1) CPU0: objcg == stock->cached_objcg
281 * 2) CPU1: we do a small allocation (e.g. 92 bytes),
282 * PAGE_SIZE bytes are charged
283 * 3) CPU1: a process from another memcg is allocating something,
284 * the stock if flushed,
285 * objcg->nr_charged_bytes = PAGE_SIZE - 92
286 * 5) CPU0: we do release this object,
287 * 92 bytes are added to stock->nr_bytes
288 * 6) CPU0: stock is flushed,
289 * 92 bytes are added to objcg->nr_charged_bytes
291 * In the result, nr_charged_bytes == PAGE_SIZE.
292 * This page will be uncharged in obj_cgroup_release().
294 nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
);
295 WARN_ON_ONCE(nr_bytes
& (PAGE_SIZE
- 1));
296 nr_pages
= nr_bytes
>> PAGE_SHIFT
;
299 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
301 spin_lock_irqsave(&css_set_lock
, flags
);
302 list_del(&objcg
->list
);
303 spin_unlock_irqrestore(&css_set_lock
, flags
);
305 percpu_ref_exit(ref
);
306 kfree_rcu(objcg
, rcu
);
309 static struct obj_cgroup
*obj_cgroup_alloc(void)
311 struct obj_cgroup
*objcg
;
314 objcg
= kzalloc(sizeof(struct obj_cgroup
), GFP_KERNEL
);
318 ret
= percpu_ref_init(&objcg
->refcnt
, obj_cgroup_release
, 0,
324 INIT_LIST_HEAD(&objcg
->list
);
328 static void memcg_reparent_objcgs(struct mem_cgroup
*memcg
,
329 struct mem_cgroup
*parent
)
331 struct obj_cgroup
*objcg
, *iter
;
333 objcg
= rcu_replace_pointer(memcg
->objcg
, NULL
, true);
335 spin_lock_irq(&css_set_lock
);
337 /* 1) Ready to reparent active objcg. */
338 list_add(&objcg
->list
, &memcg
->objcg_list
);
339 /* 2) Reparent active objcg and already reparented objcgs to parent. */
340 list_for_each_entry(iter
, &memcg
->objcg_list
, list
)
341 WRITE_ONCE(iter
->memcg
, parent
);
342 /* 3) Move already reparented objcgs to the parent's list */
343 list_splice(&memcg
->objcg_list
, &parent
->objcg_list
);
345 spin_unlock_irq(&css_set_lock
);
347 percpu_ref_kill(&objcg
->refcnt
);
351 * This will be used as a shrinker list's index.
352 * The main reason for not using cgroup id for this:
353 * this works better in sparse environments, where we have a lot of memcgs,
354 * but only a few kmem-limited. Or also, if we have, for instance, 200
355 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
356 * 200 entry array for that.
358 * The current size of the caches array is stored in memcg_nr_cache_ids. It
359 * will double each time we have to increase it.
361 static DEFINE_IDA(memcg_cache_ida
);
362 int memcg_nr_cache_ids
;
364 /* Protects memcg_nr_cache_ids */
365 static DECLARE_RWSEM(memcg_cache_ids_sem
);
367 void memcg_get_cache_ids(void)
369 down_read(&memcg_cache_ids_sem
);
372 void memcg_put_cache_ids(void)
374 up_read(&memcg_cache_ids_sem
);
378 * MIN_SIZE is different than 1, because we would like to avoid going through
379 * the alloc/free process all the time. In a small machine, 4 kmem-limited
380 * cgroups is a reasonable guess. In the future, it could be a parameter or
381 * tunable, but that is strictly not necessary.
383 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
384 * this constant directly from cgroup, but it is understandable that this is
385 * better kept as an internal representation in cgroup.c. In any case, the
386 * cgrp_id space is not getting any smaller, and we don't have to necessarily
387 * increase ours as well if it increases.
389 #define MEMCG_CACHES_MIN_SIZE 4
390 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
393 * A lot of the calls to the cache allocation functions are expected to be
394 * inlined by the compiler. Since the calls to memcg_slab_pre_alloc_hook() are
395 * conditional to this static branch, we'll have to allow modules that does
396 * kmem_cache_alloc and the such to see this symbol as well
398 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key
);
399 EXPORT_SYMBOL(memcg_kmem_enabled_key
);
403 * mem_cgroup_css_from_page - css of the memcg associated with a page
404 * @page: page of interest
406 * If memcg is bound to the default hierarchy, css of the memcg associated
407 * with @page is returned. The returned css remains associated with @page
408 * until it is released.
410 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
413 struct cgroup_subsys_state
*mem_cgroup_css_from_page(struct page
*page
)
415 struct mem_cgroup
*memcg
;
417 memcg
= page_memcg(page
);
419 if (!memcg
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
420 memcg
= root_mem_cgroup
;
426 * page_cgroup_ino - return inode number of the memcg a page is charged to
429 * Look up the closest online ancestor of the memory cgroup @page is charged to
430 * and return its inode number or 0 if @page is not charged to any cgroup. It
431 * is safe to call this function without holding a reference to @page.
433 * Note, this function is inherently racy, because there is nothing to prevent
434 * the cgroup inode from getting torn down and potentially reallocated a moment
435 * after page_cgroup_ino() returns, so it only should be used by callers that
436 * do not care (such as procfs interfaces).
438 ino_t
page_cgroup_ino(struct page
*page
)
440 struct mem_cgroup
*memcg
;
441 unsigned long ino
= 0;
444 memcg
= page_memcg_check(page
);
446 while (memcg
&& !(memcg
->css
.flags
& CSS_ONLINE
))
447 memcg
= parent_mem_cgroup(memcg
);
449 ino
= cgroup_ino(memcg
->css
.cgroup
);
454 static struct mem_cgroup_per_node
*
455 mem_cgroup_page_nodeinfo(struct mem_cgroup
*memcg
, struct page
*page
)
457 int nid
= page_to_nid(page
);
459 return memcg
->nodeinfo
[nid
];
462 static struct mem_cgroup_tree_per_node
*
463 soft_limit_tree_node(int nid
)
465 return soft_limit_tree
.rb_tree_per_node
[nid
];
468 static struct mem_cgroup_tree_per_node
*
469 soft_limit_tree_from_page(struct page
*page
)
471 int nid
= page_to_nid(page
);
473 return soft_limit_tree
.rb_tree_per_node
[nid
];
476 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node
*mz
,
477 struct mem_cgroup_tree_per_node
*mctz
,
478 unsigned long new_usage_in_excess
)
480 struct rb_node
**p
= &mctz
->rb_root
.rb_node
;
481 struct rb_node
*parent
= NULL
;
482 struct mem_cgroup_per_node
*mz_node
;
483 bool rightmost
= true;
488 mz
->usage_in_excess
= new_usage_in_excess
;
489 if (!mz
->usage_in_excess
)
493 mz_node
= rb_entry(parent
, struct mem_cgroup_per_node
,
495 if (mz
->usage_in_excess
< mz_node
->usage_in_excess
) {
504 mctz
->rb_rightmost
= &mz
->tree_node
;
506 rb_link_node(&mz
->tree_node
, parent
, p
);
507 rb_insert_color(&mz
->tree_node
, &mctz
->rb_root
);
511 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
512 struct mem_cgroup_tree_per_node
*mctz
)
517 if (&mz
->tree_node
== mctz
->rb_rightmost
)
518 mctz
->rb_rightmost
= rb_prev(&mz
->tree_node
);
520 rb_erase(&mz
->tree_node
, &mctz
->rb_root
);
524 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node
*mz
,
525 struct mem_cgroup_tree_per_node
*mctz
)
529 spin_lock_irqsave(&mctz
->lock
, flags
);
530 __mem_cgroup_remove_exceeded(mz
, mctz
);
531 spin_unlock_irqrestore(&mctz
->lock
, flags
);
534 static unsigned long soft_limit_excess(struct mem_cgroup
*memcg
)
536 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
537 unsigned long soft_limit
= READ_ONCE(memcg
->soft_limit
);
538 unsigned long excess
= 0;
540 if (nr_pages
> soft_limit
)
541 excess
= nr_pages
- soft_limit
;
546 static void mem_cgroup_update_tree(struct mem_cgroup
*memcg
, struct page
*page
)
548 unsigned long excess
;
549 struct mem_cgroup_per_node
*mz
;
550 struct mem_cgroup_tree_per_node
*mctz
;
552 mctz
= soft_limit_tree_from_page(page
);
556 * Necessary to update all ancestors when hierarchy is used.
557 * because their event counter is not touched.
559 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
560 mz
= mem_cgroup_page_nodeinfo(memcg
, page
);
561 excess
= soft_limit_excess(memcg
);
563 * We have to update the tree if mz is on RB-tree or
564 * mem is over its softlimit.
566 if (excess
|| mz
->on_tree
) {
569 spin_lock_irqsave(&mctz
->lock
, flags
);
570 /* if on-tree, remove it */
572 __mem_cgroup_remove_exceeded(mz
, mctz
);
574 * Insert again. mz->usage_in_excess will be updated.
575 * If excess is 0, no tree ops.
577 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
578 spin_unlock_irqrestore(&mctz
->lock
, flags
);
583 static void mem_cgroup_remove_from_trees(struct mem_cgroup
*memcg
)
585 struct mem_cgroup_tree_per_node
*mctz
;
586 struct mem_cgroup_per_node
*mz
;
590 mz
= memcg
->nodeinfo
[nid
];
591 mctz
= soft_limit_tree_node(nid
);
593 mem_cgroup_remove_exceeded(mz
, mctz
);
597 static struct mem_cgroup_per_node
*
598 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
600 struct mem_cgroup_per_node
*mz
;
604 if (!mctz
->rb_rightmost
)
605 goto done
; /* Nothing to reclaim from */
607 mz
= rb_entry(mctz
->rb_rightmost
,
608 struct mem_cgroup_per_node
, tree_node
);
610 * Remove the node now but someone else can add it back,
611 * we will to add it back at the end of reclaim to its correct
612 * position in the tree.
614 __mem_cgroup_remove_exceeded(mz
, mctz
);
615 if (!soft_limit_excess(mz
->memcg
) ||
616 !css_tryget(&mz
->memcg
->css
))
622 static struct mem_cgroup_per_node
*
623 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node
*mctz
)
625 struct mem_cgroup_per_node
*mz
;
627 spin_lock_irq(&mctz
->lock
);
628 mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
629 spin_unlock_irq(&mctz
->lock
);
634 * __mod_memcg_state - update cgroup memory statistics
635 * @memcg: the memory cgroup
636 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
637 * @val: delta to add to the counter, can be negative
639 void __mod_memcg_state(struct mem_cgroup
*memcg
, int idx
, int val
)
641 if (mem_cgroup_disabled())
644 __this_cpu_add(memcg
->vmstats_percpu
->state
[idx
], val
);
645 cgroup_rstat_updated(memcg
->css
.cgroup
, smp_processor_id());
648 /* idx can be of type enum memcg_stat_item or node_stat_item. */
649 static unsigned long memcg_page_state(struct mem_cgroup
*memcg
, int idx
)
651 long x
= READ_ONCE(memcg
->vmstats
.state
[idx
]);
659 /* idx can be of type enum memcg_stat_item or node_stat_item. */
660 static unsigned long memcg_page_state_local(struct mem_cgroup
*memcg
, int idx
)
665 for_each_possible_cpu(cpu
)
666 x
+= per_cpu(memcg
->vmstats_percpu
->state
[idx
], cpu
);
674 static struct mem_cgroup_per_node
*
675 parent_nodeinfo(struct mem_cgroup_per_node
*pn
, int nid
)
677 struct mem_cgroup
*parent
;
679 parent
= parent_mem_cgroup(pn
->memcg
);
682 return parent
->nodeinfo
[nid
];
685 void __mod_memcg_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
688 struct mem_cgroup_per_node
*pn
;
689 struct mem_cgroup
*memcg
;
690 long x
, threshold
= MEMCG_CHARGE_BATCH
;
692 pn
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
696 __mod_memcg_state(memcg
, idx
, val
);
699 __this_cpu_add(pn
->lruvec_stat_local
->count
[idx
], val
);
701 if (vmstat_item_in_bytes(idx
))
702 threshold
<<= PAGE_SHIFT
;
704 x
= val
+ __this_cpu_read(pn
->lruvec_stat_cpu
->count
[idx
]);
705 if (unlikely(abs(x
) > threshold
)) {
706 pg_data_t
*pgdat
= lruvec_pgdat(lruvec
);
707 struct mem_cgroup_per_node
*pi
;
709 for (pi
= pn
; pi
; pi
= parent_nodeinfo(pi
, pgdat
->node_id
))
710 atomic_long_add(x
, &pi
->lruvec_stat
[idx
]);
713 __this_cpu_write(pn
->lruvec_stat_cpu
->count
[idx
], x
);
717 * __mod_lruvec_state - update lruvec memory statistics
718 * @lruvec: the lruvec
719 * @idx: the stat item
720 * @val: delta to add to the counter, can be negative
722 * The lruvec is the intersection of the NUMA node and a cgroup. This
723 * function updates the all three counters that are affected by a
724 * change of state at this level: per-node, per-cgroup, per-lruvec.
726 void __mod_lruvec_state(struct lruvec
*lruvec
, enum node_stat_item idx
,
730 __mod_node_page_state(lruvec_pgdat(lruvec
), idx
, val
);
732 /* Update memcg and lruvec */
733 if (!mem_cgroup_disabled())
734 __mod_memcg_lruvec_state(lruvec
, idx
, val
);
737 void __mod_lruvec_page_state(struct page
*page
, enum node_stat_item idx
,
740 struct page
*head
= compound_head(page
); /* rmap on tail pages */
741 struct mem_cgroup
*memcg
;
742 pg_data_t
*pgdat
= page_pgdat(page
);
743 struct lruvec
*lruvec
;
746 memcg
= page_memcg(head
);
747 /* Untracked pages have no memcg, no lruvec. Update only the node */
750 __mod_node_page_state(pgdat
, idx
, val
);
754 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
755 __mod_lruvec_state(lruvec
, idx
, val
);
758 EXPORT_SYMBOL(__mod_lruvec_page_state
);
760 void __mod_lruvec_kmem_state(void *p
, enum node_stat_item idx
, int val
)
762 pg_data_t
*pgdat
= page_pgdat(virt_to_page(p
));
763 struct mem_cgroup
*memcg
;
764 struct lruvec
*lruvec
;
767 memcg
= mem_cgroup_from_obj(p
);
770 * Untracked pages have no memcg, no lruvec. Update only the
771 * node. If we reparent the slab objects to the root memcg,
772 * when we free the slab object, we need to update the per-memcg
773 * vmstats to keep it correct for the root memcg.
776 __mod_node_page_state(pgdat
, idx
, val
);
778 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
779 __mod_lruvec_state(lruvec
, idx
, val
);
785 * mod_objcg_mlstate() may be called with irq enabled, so
786 * mod_memcg_lruvec_state() should be used.
788 static inline void mod_objcg_mlstate(struct obj_cgroup
*objcg
,
789 struct pglist_data
*pgdat
,
790 enum node_stat_item idx
, int nr
)
792 struct mem_cgroup
*memcg
;
793 struct lruvec
*lruvec
;
796 memcg
= obj_cgroup_memcg(objcg
);
797 lruvec
= mem_cgroup_lruvec(memcg
, pgdat
);
798 mod_memcg_lruvec_state(lruvec
, idx
, nr
);
803 * __count_memcg_events - account VM events in a cgroup
804 * @memcg: the memory cgroup
805 * @idx: the event item
806 * @count: the number of events that occurred
808 void __count_memcg_events(struct mem_cgroup
*memcg
, enum vm_event_item idx
,
811 if (mem_cgroup_disabled())
814 __this_cpu_add(memcg
->vmstats_percpu
->events
[idx
], count
);
815 cgroup_rstat_updated(memcg
->css
.cgroup
, smp_processor_id());
818 static unsigned long memcg_events(struct mem_cgroup
*memcg
, int event
)
820 return READ_ONCE(memcg
->vmstats
.events
[event
]);
823 static unsigned long memcg_events_local(struct mem_cgroup
*memcg
, int event
)
828 for_each_possible_cpu(cpu
)
829 x
+= per_cpu(memcg
->vmstats_percpu
->events
[event
], cpu
);
833 static void mem_cgroup_charge_statistics(struct mem_cgroup
*memcg
,
837 /* pagein of a big page is an event. So, ignore page size */
839 __count_memcg_events(memcg
, PGPGIN
, 1);
841 __count_memcg_events(memcg
, PGPGOUT
, 1);
842 nr_pages
= -nr_pages
; /* for event */
845 __this_cpu_add(memcg
->vmstats_percpu
->nr_page_events
, nr_pages
);
848 static bool mem_cgroup_event_ratelimit(struct mem_cgroup
*memcg
,
849 enum mem_cgroup_events_target target
)
851 unsigned long val
, next
;
853 val
= __this_cpu_read(memcg
->vmstats_percpu
->nr_page_events
);
854 next
= __this_cpu_read(memcg
->vmstats_percpu
->targets
[target
]);
855 /* from time_after() in jiffies.h */
856 if ((long)(next
- val
) < 0) {
858 case MEM_CGROUP_TARGET_THRESH
:
859 next
= val
+ THRESHOLDS_EVENTS_TARGET
;
861 case MEM_CGROUP_TARGET_SOFTLIMIT
:
862 next
= val
+ SOFTLIMIT_EVENTS_TARGET
;
867 __this_cpu_write(memcg
->vmstats_percpu
->targets
[target
], next
);
874 * Check events in order.
877 static void memcg_check_events(struct mem_cgroup
*memcg
, struct page
*page
)
879 /* threshold event is triggered in finer grain than soft limit */
880 if (unlikely(mem_cgroup_event_ratelimit(memcg
,
881 MEM_CGROUP_TARGET_THRESH
))) {
884 do_softlimit
= mem_cgroup_event_ratelimit(memcg
,
885 MEM_CGROUP_TARGET_SOFTLIMIT
);
886 mem_cgroup_threshold(memcg
);
887 if (unlikely(do_softlimit
))
888 mem_cgroup_update_tree(memcg
, page
);
892 struct mem_cgroup
*mem_cgroup_from_task(struct task_struct
*p
)
895 * mm_update_next_owner() may clear mm->owner to NULL
896 * if it races with swapoff, page migration, etc.
897 * So this can be called with p == NULL.
902 return mem_cgroup_from_css(task_css(p
, memory_cgrp_id
));
904 EXPORT_SYMBOL(mem_cgroup_from_task
);
906 static __always_inline
struct mem_cgroup
*active_memcg(void)
909 return this_cpu_read(int_active_memcg
);
911 return current
->active_memcg
;
915 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
916 * @mm: mm from which memcg should be extracted. It can be NULL.
918 * Obtain a reference on mm->memcg and returns it if successful. If mm
919 * is NULL, then the memcg is chosen as follows:
920 * 1) The active memcg, if set.
921 * 2) current->mm->memcg, if available
923 * If mem_cgroup is disabled, NULL is returned.
925 struct mem_cgroup
*get_mem_cgroup_from_mm(struct mm_struct
*mm
)
927 struct mem_cgroup
*memcg
;
929 if (mem_cgroup_disabled())
933 * Page cache insertions can happen without an
934 * actual mm context, e.g. during disk probing
935 * on boot, loopback IO, acct() writes etc.
937 * No need to css_get on root memcg as the reference
938 * counting is disabled on the root level in the
939 * cgroup core. See CSS_NO_REF.
942 memcg
= active_memcg();
943 if (unlikely(memcg
)) {
944 /* remote memcg must hold a ref */
945 css_get(&memcg
->css
);
950 return root_mem_cgroup
;
955 memcg
= mem_cgroup_from_task(rcu_dereference(mm
->owner
));
956 if (unlikely(!memcg
))
957 memcg
= root_mem_cgroup
;
958 } while (!css_tryget(&memcg
->css
));
962 EXPORT_SYMBOL(get_mem_cgroup_from_mm
);
964 static __always_inline
bool memcg_kmem_bypass(void)
966 /* Allow remote memcg charging from any context. */
967 if (unlikely(active_memcg()))
970 /* Memcg to charge can't be determined. */
971 if (in_interrupt() || !current
->mm
|| (current
->flags
& PF_KTHREAD
))
978 * mem_cgroup_iter - iterate over memory cgroup hierarchy
979 * @root: hierarchy root
980 * @prev: previously returned memcg, NULL on first invocation
981 * @reclaim: cookie for shared reclaim walks, NULL for full walks
983 * Returns references to children of the hierarchy below @root, or
984 * @root itself, or %NULL after a full round-trip.
986 * Caller must pass the return value in @prev on subsequent
987 * invocations for reference counting, or use mem_cgroup_iter_break()
988 * to cancel a hierarchy walk before the round-trip is complete.
990 * Reclaimers can specify a node in @reclaim to divide up the memcgs
991 * in the hierarchy among all concurrent reclaimers operating on the
994 struct mem_cgroup
*mem_cgroup_iter(struct mem_cgroup
*root
,
995 struct mem_cgroup
*prev
,
996 struct mem_cgroup_reclaim_cookie
*reclaim
)
998 struct mem_cgroup_reclaim_iter
*iter
;
999 struct cgroup_subsys_state
*css
= NULL
;
1000 struct mem_cgroup
*memcg
= NULL
;
1001 struct mem_cgroup
*pos
= NULL
;
1003 if (mem_cgroup_disabled())
1007 root
= root_mem_cgroup
;
1009 if (prev
&& !reclaim
)
1015 struct mem_cgroup_per_node
*mz
;
1017 mz
= root
->nodeinfo
[reclaim
->pgdat
->node_id
];
1020 if (prev
&& reclaim
->generation
!= iter
->generation
)
1024 pos
= READ_ONCE(iter
->position
);
1025 if (!pos
|| css_tryget(&pos
->css
))
1028 * css reference reached zero, so iter->position will
1029 * be cleared by ->css_released. However, we should not
1030 * rely on this happening soon, because ->css_released
1031 * is called from a work queue, and by busy-waiting we
1032 * might block it. So we clear iter->position right
1035 (void)cmpxchg(&iter
->position
, pos
, NULL
);
1043 css
= css_next_descendant_pre(css
, &root
->css
);
1046 * Reclaimers share the hierarchy walk, and a
1047 * new one might jump in right at the end of
1048 * the hierarchy - make sure they see at least
1049 * one group and restart from the beginning.
1057 * Verify the css and acquire a reference. The root
1058 * is provided by the caller, so we know it's alive
1059 * and kicking, and don't take an extra reference.
1061 memcg
= mem_cgroup_from_css(css
);
1063 if (css
== &root
->css
)
1066 if (css_tryget(css
))
1074 * The position could have already been updated by a competing
1075 * thread, so check that the value hasn't changed since we read
1076 * it to avoid reclaiming from the same cgroup twice.
1078 (void)cmpxchg(&iter
->position
, pos
, memcg
);
1086 reclaim
->generation
= iter
->generation
;
1091 if (prev
&& prev
!= root
)
1092 css_put(&prev
->css
);
1098 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1099 * @root: hierarchy root
1100 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1102 void mem_cgroup_iter_break(struct mem_cgroup
*root
,
1103 struct mem_cgroup
*prev
)
1106 root
= root_mem_cgroup
;
1107 if (prev
&& prev
!= root
)
1108 css_put(&prev
->css
);
1111 static void __invalidate_reclaim_iterators(struct mem_cgroup
*from
,
1112 struct mem_cgroup
*dead_memcg
)
1114 struct mem_cgroup_reclaim_iter
*iter
;
1115 struct mem_cgroup_per_node
*mz
;
1118 for_each_node(nid
) {
1119 mz
= from
->nodeinfo
[nid
];
1121 cmpxchg(&iter
->position
, dead_memcg
, NULL
);
1125 static void invalidate_reclaim_iterators(struct mem_cgroup
*dead_memcg
)
1127 struct mem_cgroup
*memcg
= dead_memcg
;
1128 struct mem_cgroup
*last
;
1131 __invalidate_reclaim_iterators(memcg
, dead_memcg
);
1133 } while ((memcg
= parent_mem_cgroup(memcg
)));
1136 * When cgruop1 non-hierarchy mode is used,
1137 * parent_mem_cgroup() does not walk all the way up to the
1138 * cgroup root (root_mem_cgroup). So we have to handle
1139 * dead_memcg from cgroup root separately.
1141 if (last
!= root_mem_cgroup
)
1142 __invalidate_reclaim_iterators(root_mem_cgroup
,
1147 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1148 * @memcg: hierarchy root
1149 * @fn: function to call for each task
1150 * @arg: argument passed to @fn
1152 * This function iterates over tasks attached to @memcg or to any of its
1153 * descendants and calls @fn for each task. If @fn returns a non-zero
1154 * value, the function breaks the iteration loop and returns the value.
1155 * Otherwise, it will iterate over all tasks and return 0.
1157 * This function must not be called for the root memory cgroup.
1159 int mem_cgroup_scan_tasks(struct mem_cgroup
*memcg
,
1160 int (*fn
)(struct task_struct
*, void *), void *arg
)
1162 struct mem_cgroup
*iter
;
1165 BUG_ON(memcg
== root_mem_cgroup
);
1167 for_each_mem_cgroup_tree(iter
, memcg
) {
1168 struct css_task_iter it
;
1169 struct task_struct
*task
;
1171 css_task_iter_start(&iter
->css
, CSS_TASK_ITER_PROCS
, &it
);
1172 while (!ret
&& (task
= css_task_iter_next(&it
)))
1173 ret
= fn(task
, arg
);
1174 css_task_iter_end(&it
);
1176 mem_cgroup_iter_break(memcg
, iter
);
1183 #ifdef CONFIG_DEBUG_VM
1184 void lruvec_memcg_debug(struct lruvec
*lruvec
, struct page
*page
)
1186 struct mem_cgroup
*memcg
;
1188 if (mem_cgroup_disabled())
1191 memcg
= page_memcg(page
);
1194 VM_BUG_ON_PAGE(lruvec_memcg(lruvec
) != root_mem_cgroup
, page
);
1196 VM_BUG_ON_PAGE(lruvec_memcg(lruvec
) != memcg
, page
);
1201 * lock_page_lruvec - lock and return lruvec for a given page.
1204 * These functions are safe to use under any of the following conditions:
1207 * - lock_page_memcg()
1208 * - page->_refcount is zero
1210 struct lruvec
*lock_page_lruvec(struct page
*page
)
1212 struct lruvec
*lruvec
;
1214 lruvec
= mem_cgroup_page_lruvec(page
);
1215 spin_lock(&lruvec
->lru_lock
);
1217 lruvec_memcg_debug(lruvec
, page
);
1222 struct lruvec
*lock_page_lruvec_irq(struct page
*page
)
1224 struct lruvec
*lruvec
;
1226 lruvec
= mem_cgroup_page_lruvec(page
);
1227 spin_lock_irq(&lruvec
->lru_lock
);
1229 lruvec_memcg_debug(lruvec
, page
);
1234 struct lruvec
*lock_page_lruvec_irqsave(struct page
*page
, unsigned long *flags
)
1236 struct lruvec
*lruvec
;
1238 lruvec
= mem_cgroup_page_lruvec(page
);
1239 spin_lock_irqsave(&lruvec
->lru_lock
, *flags
);
1241 lruvec_memcg_debug(lruvec
, page
);
1247 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1248 * @lruvec: mem_cgroup per zone lru vector
1249 * @lru: index of lru list the page is sitting on
1250 * @zid: zone id of the accounted pages
1251 * @nr_pages: positive when adding or negative when removing
1253 * This function must be called under lru_lock, just before a page is added
1254 * to or just after a page is removed from an lru list (that ordering being
1255 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1257 void mem_cgroup_update_lru_size(struct lruvec
*lruvec
, enum lru_list lru
,
1258 int zid
, int nr_pages
)
1260 struct mem_cgroup_per_node
*mz
;
1261 unsigned long *lru_size
;
1264 if (mem_cgroup_disabled())
1267 mz
= container_of(lruvec
, struct mem_cgroup_per_node
, lruvec
);
1268 lru_size
= &mz
->lru_zone_size
[zid
][lru
];
1271 *lru_size
+= nr_pages
;
1274 if (WARN_ONCE(size
< 0,
1275 "%s(%p, %d, %d): lru_size %ld\n",
1276 __func__
, lruvec
, lru
, nr_pages
, size
)) {
1282 *lru_size
+= nr_pages
;
1286 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1287 * @memcg: the memory cgroup
1289 * Returns the maximum amount of memory @mem can be charged with, in
1292 static unsigned long mem_cgroup_margin(struct mem_cgroup
*memcg
)
1294 unsigned long margin
= 0;
1295 unsigned long count
;
1296 unsigned long limit
;
1298 count
= page_counter_read(&memcg
->memory
);
1299 limit
= READ_ONCE(memcg
->memory
.max
);
1301 margin
= limit
- count
;
1303 if (do_memsw_account()) {
1304 count
= page_counter_read(&memcg
->memsw
);
1305 limit
= READ_ONCE(memcg
->memsw
.max
);
1307 margin
= min(margin
, limit
- count
);
1316 * A routine for checking "mem" is under move_account() or not.
1318 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1319 * moving cgroups. This is for waiting at high-memory pressure
1322 static bool mem_cgroup_under_move(struct mem_cgroup
*memcg
)
1324 struct mem_cgroup
*from
;
1325 struct mem_cgroup
*to
;
1328 * Unlike task_move routines, we access mc.to, mc.from not under
1329 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1331 spin_lock(&mc
.lock
);
1337 ret
= mem_cgroup_is_descendant(from
, memcg
) ||
1338 mem_cgroup_is_descendant(to
, memcg
);
1340 spin_unlock(&mc
.lock
);
1344 static bool mem_cgroup_wait_acct_move(struct mem_cgroup
*memcg
)
1346 if (mc
.moving_task
&& current
!= mc
.moving_task
) {
1347 if (mem_cgroup_under_move(memcg
)) {
1349 prepare_to_wait(&mc
.waitq
, &wait
, TASK_INTERRUPTIBLE
);
1350 /* moving charge context might have finished. */
1353 finish_wait(&mc
.waitq
, &wait
);
1360 struct memory_stat
{
1365 static const struct memory_stat memory_stats
[] = {
1366 { "anon", NR_ANON_MAPPED
},
1367 { "file", NR_FILE_PAGES
},
1368 { "kernel_stack", NR_KERNEL_STACK_KB
},
1369 { "pagetables", NR_PAGETABLE
},
1370 { "percpu", MEMCG_PERCPU_B
},
1371 { "sock", MEMCG_SOCK
},
1372 { "shmem", NR_SHMEM
},
1373 { "file_mapped", NR_FILE_MAPPED
},
1374 { "file_dirty", NR_FILE_DIRTY
},
1375 { "file_writeback", NR_WRITEBACK
},
1377 { "swapcached", NR_SWAPCACHE
},
1379 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1380 { "anon_thp", NR_ANON_THPS
},
1381 { "file_thp", NR_FILE_THPS
},
1382 { "shmem_thp", NR_SHMEM_THPS
},
1384 { "inactive_anon", NR_INACTIVE_ANON
},
1385 { "active_anon", NR_ACTIVE_ANON
},
1386 { "inactive_file", NR_INACTIVE_FILE
},
1387 { "active_file", NR_ACTIVE_FILE
},
1388 { "unevictable", NR_UNEVICTABLE
},
1389 { "slab_reclaimable", NR_SLAB_RECLAIMABLE_B
},
1390 { "slab_unreclaimable", NR_SLAB_UNRECLAIMABLE_B
},
1392 /* The memory events */
1393 { "workingset_refault_anon", WORKINGSET_REFAULT_ANON
},
1394 { "workingset_refault_file", WORKINGSET_REFAULT_FILE
},
1395 { "workingset_activate_anon", WORKINGSET_ACTIVATE_ANON
},
1396 { "workingset_activate_file", WORKINGSET_ACTIVATE_FILE
},
1397 { "workingset_restore_anon", WORKINGSET_RESTORE_ANON
},
1398 { "workingset_restore_file", WORKINGSET_RESTORE_FILE
},
1399 { "workingset_nodereclaim", WORKINGSET_NODERECLAIM
},
1402 /* Translate stat items to the correct unit for memory.stat output */
1403 static int memcg_page_state_unit(int item
)
1406 case MEMCG_PERCPU_B
:
1407 case NR_SLAB_RECLAIMABLE_B
:
1408 case NR_SLAB_UNRECLAIMABLE_B
:
1409 case WORKINGSET_REFAULT_ANON
:
1410 case WORKINGSET_REFAULT_FILE
:
1411 case WORKINGSET_ACTIVATE_ANON
:
1412 case WORKINGSET_ACTIVATE_FILE
:
1413 case WORKINGSET_RESTORE_ANON
:
1414 case WORKINGSET_RESTORE_FILE
:
1415 case WORKINGSET_NODERECLAIM
:
1417 case NR_KERNEL_STACK_KB
:
1424 static inline unsigned long memcg_page_state_output(struct mem_cgroup
*memcg
,
1427 return memcg_page_state(memcg
, item
) * memcg_page_state_unit(item
);
1430 static char *memory_stat_format(struct mem_cgroup
*memcg
)
1435 seq_buf_init(&s
, kmalloc(PAGE_SIZE
, GFP_KERNEL
), PAGE_SIZE
);
1440 * Provide statistics on the state of the memory subsystem as
1441 * well as cumulative event counters that show past behavior.
1443 * This list is ordered following a combination of these gradients:
1444 * 1) generic big picture -> specifics and details
1445 * 2) reflecting userspace activity -> reflecting kernel heuristics
1447 * Current memory state:
1449 cgroup_rstat_flush(memcg
->css
.cgroup
);
1451 for (i
= 0; i
< ARRAY_SIZE(memory_stats
); i
++) {
1454 size
= memcg_page_state_output(memcg
, memory_stats
[i
].idx
);
1455 seq_buf_printf(&s
, "%s %llu\n", memory_stats
[i
].name
, size
);
1457 if (unlikely(memory_stats
[i
].idx
== NR_SLAB_UNRECLAIMABLE_B
)) {
1458 size
+= memcg_page_state_output(memcg
,
1459 NR_SLAB_RECLAIMABLE_B
);
1460 seq_buf_printf(&s
, "slab %llu\n", size
);
1464 /* Accumulated memory events */
1466 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGFAULT
),
1467 memcg_events(memcg
, PGFAULT
));
1468 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGMAJFAULT
),
1469 memcg_events(memcg
, PGMAJFAULT
));
1470 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGREFILL
),
1471 memcg_events(memcg
, PGREFILL
));
1472 seq_buf_printf(&s
, "pgscan %lu\n",
1473 memcg_events(memcg
, PGSCAN_KSWAPD
) +
1474 memcg_events(memcg
, PGSCAN_DIRECT
));
1475 seq_buf_printf(&s
, "pgsteal %lu\n",
1476 memcg_events(memcg
, PGSTEAL_KSWAPD
) +
1477 memcg_events(memcg
, PGSTEAL_DIRECT
));
1478 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGACTIVATE
),
1479 memcg_events(memcg
, PGACTIVATE
));
1480 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGDEACTIVATE
),
1481 memcg_events(memcg
, PGDEACTIVATE
));
1482 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREE
),
1483 memcg_events(memcg
, PGLAZYFREE
));
1484 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(PGLAZYFREED
),
1485 memcg_events(memcg
, PGLAZYFREED
));
1487 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1488 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC
),
1489 memcg_events(memcg
, THP_FAULT_ALLOC
));
1490 seq_buf_printf(&s
, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC
),
1491 memcg_events(memcg
, THP_COLLAPSE_ALLOC
));
1492 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1494 /* The above should easily fit into one page */
1495 WARN_ON_ONCE(seq_buf_has_overflowed(&s
));
1500 #define K(x) ((x) << (PAGE_SHIFT-10))
1502 * mem_cgroup_print_oom_context: Print OOM information relevant to
1503 * memory controller.
1504 * @memcg: The memory cgroup that went over limit
1505 * @p: Task that is going to be killed
1507 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1510 void mem_cgroup_print_oom_context(struct mem_cgroup
*memcg
, struct task_struct
*p
)
1515 pr_cont(",oom_memcg=");
1516 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1518 pr_cont(",global_oom");
1520 pr_cont(",task_memcg=");
1521 pr_cont_cgroup_path(task_cgroup(p
, memory_cgrp_id
));
1527 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1528 * memory controller.
1529 * @memcg: The memory cgroup that went over limit
1531 void mem_cgroup_print_oom_meminfo(struct mem_cgroup
*memcg
)
1535 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1536 K((u64
)page_counter_read(&memcg
->memory
)),
1537 K((u64
)READ_ONCE(memcg
->memory
.max
)), memcg
->memory
.failcnt
);
1538 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1539 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1540 K((u64
)page_counter_read(&memcg
->swap
)),
1541 K((u64
)READ_ONCE(memcg
->swap
.max
)), memcg
->swap
.failcnt
);
1543 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1544 K((u64
)page_counter_read(&memcg
->memsw
)),
1545 K((u64
)memcg
->memsw
.max
), memcg
->memsw
.failcnt
);
1546 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1547 K((u64
)page_counter_read(&memcg
->kmem
)),
1548 K((u64
)memcg
->kmem
.max
), memcg
->kmem
.failcnt
);
1551 pr_info("Memory cgroup stats for ");
1552 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1554 buf
= memory_stat_format(memcg
);
1562 * Return the memory (and swap, if configured) limit for a memcg.
1564 unsigned long mem_cgroup_get_max(struct mem_cgroup
*memcg
)
1566 unsigned long max
= READ_ONCE(memcg
->memory
.max
);
1568 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
1569 if (mem_cgroup_swappiness(memcg
))
1570 max
+= min(READ_ONCE(memcg
->swap
.max
),
1571 (unsigned long)total_swap_pages
);
1573 if (mem_cgroup_swappiness(memcg
)) {
1574 /* Calculate swap excess capacity from memsw limit */
1575 unsigned long swap
= READ_ONCE(memcg
->memsw
.max
) - max
;
1577 max
+= min(swap
, (unsigned long)total_swap_pages
);
1583 unsigned long mem_cgroup_size(struct mem_cgroup
*memcg
)
1585 return page_counter_read(&memcg
->memory
);
1588 static bool mem_cgroup_out_of_memory(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
1591 struct oom_control oc
= {
1595 .gfp_mask
= gfp_mask
,
1600 if (mutex_lock_killable(&oom_lock
))
1603 if (mem_cgroup_margin(memcg
) >= (1 << order
))
1607 * A few threads which were not waiting at mutex_lock_killable() can
1608 * fail to bail out. Therefore, check again after holding oom_lock.
1610 ret
= should_force_charge() || out_of_memory(&oc
);
1613 mutex_unlock(&oom_lock
);
1617 static int mem_cgroup_soft_reclaim(struct mem_cgroup
*root_memcg
,
1620 unsigned long *total_scanned
)
1622 struct mem_cgroup
*victim
= NULL
;
1625 unsigned long excess
;
1626 unsigned long nr_scanned
;
1627 struct mem_cgroup_reclaim_cookie reclaim
= {
1631 excess
= soft_limit_excess(root_memcg
);
1634 victim
= mem_cgroup_iter(root_memcg
, victim
, &reclaim
);
1639 * If we have not been able to reclaim
1640 * anything, it might because there are
1641 * no reclaimable pages under this hierarchy
1646 * We want to do more targeted reclaim.
1647 * excess >> 2 is not to excessive so as to
1648 * reclaim too much, nor too less that we keep
1649 * coming back to reclaim from this cgroup
1651 if (total
>= (excess
>> 2) ||
1652 (loop
> MEM_CGROUP_MAX_RECLAIM_LOOPS
))
1657 total
+= mem_cgroup_shrink_node(victim
, gfp_mask
, false,
1658 pgdat
, &nr_scanned
);
1659 *total_scanned
+= nr_scanned
;
1660 if (!soft_limit_excess(root_memcg
))
1663 mem_cgroup_iter_break(root_memcg
, victim
);
1667 #ifdef CONFIG_LOCKDEP
1668 static struct lockdep_map memcg_oom_lock_dep_map
= {
1669 .name
= "memcg_oom_lock",
1673 static DEFINE_SPINLOCK(memcg_oom_lock
);
1676 * Check OOM-Killer is already running under our hierarchy.
1677 * If someone is running, return false.
1679 static bool mem_cgroup_oom_trylock(struct mem_cgroup
*memcg
)
1681 struct mem_cgroup
*iter
, *failed
= NULL
;
1683 spin_lock(&memcg_oom_lock
);
1685 for_each_mem_cgroup_tree(iter
, memcg
) {
1686 if (iter
->oom_lock
) {
1688 * this subtree of our hierarchy is already locked
1689 * so we cannot give a lock.
1692 mem_cgroup_iter_break(memcg
, iter
);
1695 iter
->oom_lock
= true;
1700 * OK, we failed to lock the whole subtree so we have
1701 * to clean up what we set up to the failing subtree
1703 for_each_mem_cgroup_tree(iter
, memcg
) {
1704 if (iter
== failed
) {
1705 mem_cgroup_iter_break(memcg
, iter
);
1708 iter
->oom_lock
= false;
1711 mutex_acquire(&memcg_oom_lock_dep_map
, 0, 1, _RET_IP_
);
1713 spin_unlock(&memcg_oom_lock
);
1718 static void mem_cgroup_oom_unlock(struct mem_cgroup
*memcg
)
1720 struct mem_cgroup
*iter
;
1722 spin_lock(&memcg_oom_lock
);
1723 mutex_release(&memcg_oom_lock_dep_map
, _RET_IP_
);
1724 for_each_mem_cgroup_tree(iter
, memcg
)
1725 iter
->oom_lock
= false;
1726 spin_unlock(&memcg_oom_lock
);
1729 static void mem_cgroup_mark_under_oom(struct mem_cgroup
*memcg
)
1731 struct mem_cgroup
*iter
;
1733 spin_lock(&memcg_oom_lock
);
1734 for_each_mem_cgroup_tree(iter
, memcg
)
1736 spin_unlock(&memcg_oom_lock
);
1739 static void mem_cgroup_unmark_under_oom(struct mem_cgroup
*memcg
)
1741 struct mem_cgroup
*iter
;
1744 * Be careful about under_oom underflows because a child memcg
1745 * could have been added after mem_cgroup_mark_under_oom.
1747 spin_lock(&memcg_oom_lock
);
1748 for_each_mem_cgroup_tree(iter
, memcg
)
1749 if (iter
->under_oom
> 0)
1751 spin_unlock(&memcg_oom_lock
);
1754 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq
);
1756 struct oom_wait_info
{
1757 struct mem_cgroup
*memcg
;
1758 wait_queue_entry_t wait
;
1761 static int memcg_oom_wake_function(wait_queue_entry_t
*wait
,
1762 unsigned mode
, int sync
, void *arg
)
1764 struct mem_cgroup
*wake_memcg
= (struct mem_cgroup
*)arg
;
1765 struct mem_cgroup
*oom_wait_memcg
;
1766 struct oom_wait_info
*oom_wait_info
;
1768 oom_wait_info
= container_of(wait
, struct oom_wait_info
, wait
);
1769 oom_wait_memcg
= oom_wait_info
->memcg
;
1771 if (!mem_cgroup_is_descendant(wake_memcg
, oom_wait_memcg
) &&
1772 !mem_cgroup_is_descendant(oom_wait_memcg
, wake_memcg
))
1774 return autoremove_wake_function(wait
, mode
, sync
, arg
);
1777 static void memcg_oom_recover(struct mem_cgroup
*memcg
)
1780 * For the following lockless ->under_oom test, the only required
1781 * guarantee is that it must see the state asserted by an OOM when
1782 * this function is called as a result of userland actions
1783 * triggered by the notification of the OOM. This is trivially
1784 * achieved by invoking mem_cgroup_mark_under_oom() before
1785 * triggering notification.
1787 if (memcg
&& memcg
->under_oom
)
1788 __wake_up(&memcg_oom_waitq
, TASK_NORMAL
, 0, memcg
);
1798 static enum oom_status
mem_cgroup_oom(struct mem_cgroup
*memcg
, gfp_t mask
, int order
)
1800 enum oom_status ret
;
1803 if (order
> PAGE_ALLOC_COSTLY_ORDER
)
1806 memcg_memory_event(memcg
, MEMCG_OOM
);
1809 * We are in the middle of the charge context here, so we
1810 * don't want to block when potentially sitting on a callstack
1811 * that holds all kinds of filesystem and mm locks.
1813 * cgroup1 allows disabling the OOM killer and waiting for outside
1814 * handling until the charge can succeed; remember the context and put
1815 * the task to sleep at the end of the page fault when all locks are
1818 * On the other hand, in-kernel OOM killer allows for an async victim
1819 * memory reclaim (oom_reaper) and that means that we are not solely
1820 * relying on the oom victim to make a forward progress and we can
1821 * invoke the oom killer here.
1823 * Please note that mem_cgroup_out_of_memory might fail to find a
1824 * victim and then we have to bail out from the charge path.
1826 if (memcg
->oom_kill_disable
) {
1827 if (!current
->in_user_fault
)
1829 css_get(&memcg
->css
);
1830 current
->memcg_in_oom
= memcg
;
1831 current
->memcg_oom_gfp_mask
= mask
;
1832 current
->memcg_oom_order
= order
;
1837 mem_cgroup_mark_under_oom(memcg
);
1839 locked
= mem_cgroup_oom_trylock(memcg
);
1842 mem_cgroup_oom_notify(memcg
);
1844 mem_cgroup_unmark_under_oom(memcg
);
1845 if (mem_cgroup_out_of_memory(memcg
, mask
, order
))
1851 mem_cgroup_oom_unlock(memcg
);
1857 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1858 * @handle: actually kill/wait or just clean up the OOM state
1860 * This has to be called at the end of a page fault if the memcg OOM
1861 * handler was enabled.
1863 * Memcg supports userspace OOM handling where failed allocations must
1864 * sleep on a waitqueue until the userspace task resolves the
1865 * situation. Sleeping directly in the charge context with all kinds
1866 * of locks held is not a good idea, instead we remember an OOM state
1867 * in the task and mem_cgroup_oom_synchronize() has to be called at
1868 * the end of the page fault to complete the OOM handling.
1870 * Returns %true if an ongoing memcg OOM situation was detected and
1871 * completed, %false otherwise.
1873 bool mem_cgroup_oom_synchronize(bool handle
)
1875 struct mem_cgroup
*memcg
= current
->memcg_in_oom
;
1876 struct oom_wait_info owait
;
1879 /* OOM is global, do not handle */
1886 owait
.memcg
= memcg
;
1887 owait
.wait
.flags
= 0;
1888 owait
.wait
.func
= memcg_oom_wake_function
;
1889 owait
.wait
.private = current
;
1890 INIT_LIST_HEAD(&owait
.wait
.entry
);
1892 prepare_to_wait(&memcg_oom_waitq
, &owait
.wait
, TASK_KILLABLE
);
1893 mem_cgroup_mark_under_oom(memcg
);
1895 locked
= mem_cgroup_oom_trylock(memcg
);
1898 mem_cgroup_oom_notify(memcg
);
1900 if (locked
&& !memcg
->oom_kill_disable
) {
1901 mem_cgroup_unmark_under_oom(memcg
);
1902 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1903 mem_cgroup_out_of_memory(memcg
, current
->memcg_oom_gfp_mask
,
1904 current
->memcg_oom_order
);
1907 mem_cgroup_unmark_under_oom(memcg
);
1908 finish_wait(&memcg_oom_waitq
, &owait
.wait
);
1912 mem_cgroup_oom_unlock(memcg
);
1914 * There is no guarantee that an OOM-lock contender
1915 * sees the wakeups triggered by the OOM kill
1916 * uncharges. Wake any sleepers explicitly.
1918 memcg_oom_recover(memcg
);
1921 current
->memcg_in_oom
= NULL
;
1922 css_put(&memcg
->css
);
1927 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1928 * @victim: task to be killed by the OOM killer
1929 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1931 * Returns a pointer to a memory cgroup, which has to be cleaned up
1932 * by killing all belonging OOM-killable tasks.
1934 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1936 struct mem_cgroup
*mem_cgroup_get_oom_group(struct task_struct
*victim
,
1937 struct mem_cgroup
*oom_domain
)
1939 struct mem_cgroup
*oom_group
= NULL
;
1940 struct mem_cgroup
*memcg
;
1942 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
1946 oom_domain
= root_mem_cgroup
;
1950 memcg
= mem_cgroup_from_task(victim
);
1951 if (memcg
== root_mem_cgroup
)
1955 * If the victim task has been asynchronously moved to a different
1956 * memory cgroup, we might end up killing tasks outside oom_domain.
1957 * In this case it's better to ignore memory.group.oom.
1959 if (unlikely(!mem_cgroup_is_descendant(memcg
, oom_domain
)))
1963 * Traverse the memory cgroup hierarchy from the victim task's
1964 * cgroup up to the OOMing cgroup (or root) to find the
1965 * highest-level memory cgroup with oom.group set.
1967 for (; memcg
; memcg
= parent_mem_cgroup(memcg
)) {
1968 if (memcg
->oom_group
)
1971 if (memcg
== oom_domain
)
1976 css_get(&oom_group
->css
);
1983 void mem_cgroup_print_oom_group(struct mem_cgroup
*memcg
)
1985 pr_info("Tasks in ");
1986 pr_cont_cgroup_path(memcg
->css
.cgroup
);
1987 pr_cont(" are going to be killed due to memory.oom.group set\n");
1991 * lock_page_memcg - lock a page and memcg binding
1994 * This function protects unlocked LRU pages from being moved to
1997 * It ensures lifetime of the locked memcg. Caller is responsible
1998 * for the lifetime of the page.
2000 void lock_page_memcg(struct page
*page
)
2002 struct page
*head
= compound_head(page
); /* rmap on tail pages */
2003 struct mem_cgroup
*memcg
;
2004 unsigned long flags
;
2007 * The RCU lock is held throughout the transaction. The fast
2008 * path can get away without acquiring the memcg->move_lock
2009 * because page moving starts with an RCU grace period.
2013 if (mem_cgroup_disabled())
2016 memcg
= page_memcg(head
);
2017 if (unlikely(!memcg
))
2020 #ifdef CONFIG_PROVE_LOCKING
2021 local_irq_save(flags
);
2022 might_lock(&memcg
->move_lock
);
2023 local_irq_restore(flags
);
2026 if (atomic_read(&memcg
->moving_account
) <= 0)
2029 spin_lock_irqsave(&memcg
->move_lock
, flags
);
2030 if (memcg
!= page_memcg(head
)) {
2031 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2036 * When charge migration first begins, we can have multiple
2037 * critical sections holding the fast-path RCU lock and one
2038 * holding the slowpath move_lock. Track the task who has the
2039 * move_lock for unlock_page_memcg().
2041 memcg
->move_lock_task
= current
;
2042 memcg
->move_lock_flags
= flags
;
2044 EXPORT_SYMBOL(lock_page_memcg
);
2046 static void __unlock_page_memcg(struct mem_cgroup
*memcg
)
2048 if (memcg
&& memcg
->move_lock_task
== current
) {
2049 unsigned long flags
= memcg
->move_lock_flags
;
2051 memcg
->move_lock_task
= NULL
;
2052 memcg
->move_lock_flags
= 0;
2054 spin_unlock_irqrestore(&memcg
->move_lock
, flags
);
2061 * unlock_page_memcg - unlock a page and memcg binding
2064 void unlock_page_memcg(struct page
*page
)
2066 struct page
*head
= compound_head(page
);
2068 __unlock_page_memcg(page_memcg(head
));
2070 EXPORT_SYMBOL(unlock_page_memcg
);
2073 #ifdef CONFIG_MEMCG_KMEM
2074 struct obj_cgroup
*cached_objcg
;
2075 struct pglist_data
*cached_pgdat
;
2076 unsigned int nr_bytes
;
2077 int nr_slab_reclaimable_b
;
2078 int nr_slab_unreclaimable_b
;
2084 struct memcg_stock_pcp
{
2085 struct mem_cgroup
*cached
; /* this never be root cgroup */
2086 unsigned int nr_pages
;
2087 struct obj_stock task_obj
;
2088 struct obj_stock irq_obj
;
2090 struct work_struct work
;
2091 unsigned long flags
;
2092 #define FLUSHING_CACHED_CHARGE 0
2094 static DEFINE_PER_CPU(struct memcg_stock_pcp
, memcg_stock
);
2095 static DEFINE_MUTEX(percpu_charge_mutex
);
2097 #ifdef CONFIG_MEMCG_KMEM
2098 static void drain_obj_stock(struct obj_stock
*stock
);
2099 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
2100 struct mem_cgroup
*root_memcg
);
2103 static inline void drain_obj_stock(struct obj_stock
*stock
)
2106 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
2107 struct mem_cgroup
*root_memcg
)
2114 * Most kmem_cache_alloc() calls are from user context. The irq disable/enable
2115 * sequence used in this case to access content from object stock is slow.
2116 * To optimize for user context access, there are now two object stocks for
2117 * task context and interrupt context access respectively.
2119 * The task context object stock can be accessed by disabling preemption only
2120 * which is cheap in non-preempt kernel. The interrupt context object stock
2121 * can only be accessed after disabling interrupt. User context code can
2122 * access interrupt object stock, but not vice versa.
2124 static inline struct obj_stock
*get_obj_stock(unsigned long *pflags
)
2126 struct memcg_stock_pcp
*stock
;
2128 if (likely(in_task())) {
2131 stock
= this_cpu_ptr(&memcg_stock
);
2132 return &stock
->task_obj
;
2135 local_irq_save(*pflags
);
2136 stock
= this_cpu_ptr(&memcg_stock
);
2137 return &stock
->irq_obj
;
2140 static inline void put_obj_stock(unsigned long flags
)
2142 if (likely(in_task()))
2145 local_irq_restore(flags
);
2149 * consume_stock: Try to consume stocked charge on this cpu.
2150 * @memcg: memcg to consume from.
2151 * @nr_pages: how many pages to charge.
2153 * The charges will only happen if @memcg matches the current cpu's memcg
2154 * stock, and at least @nr_pages are available in that stock. Failure to
2155 * service an allocation will refill the stock.
2157 * returns true if successful, false otherwise.
2159 static bool consume_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2161 struct memcg_stock_pcp
*stock
;
2162 unsigned long flags
;
2165 if (nr_pages
> MEMCG_CHARGE_BATCH
)
2168 local_irq_save(flags
);
2170 stock
= this_cpu_ptr(&memcg_stock
);
2171 if (memcg
== stock
->cached
&& stock
->nr_pages
>= nr_pages
) {
2172 stock
->nr_pages
-= nr_pages
;
2176 local_irq_restore(flags
);
2182 * Returns stocks cached in percpu and reset cached information.
2184 static void drain_stock(struct memcg_stock_pcp
*stock
)
2186 struct mem_cgroup
*old
= stock
->cached
;
2191 if (stock
->nr_pages
) {
2192 page_counter_uncharge(&old
->memory
, stock
->nr_pages
);
2193 if (do_memsw_account())
2194 page_counter_uncharge(&old
->memsw
, stock
->nr_pages
);
2195 stock
->nr_pages
= 0;
2199 stock
->cached
= NULL
;
2202 static void drain_local_stock(struct work_struct
*dummy
)
2204 struct memcg_stock_pcp
*stock
;
2205 unsigned long flags
;
2208 * The only protection from memory hotplug vs. drain_stock races is
2209 * that we always operate on local CPU stock here with IRQ disabled
2211 local_irq_save(flags
);
2213 stock
= this_cpu_ptr(&memcg_stock
);
2214 drain_obj_stock(&stock
->irq_obj
);
2216 drain_obj_stock(&stock
->task_obj
);
2218 clear_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
);
2220 local_irq_restore(flags
);
2224 * Cache charges(val) to local per_cpu area.
2225 * This will be consumed by consume_stock() function, later.
2227 static void refill_stock(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2229 struct memcg_stock_pcp
*stock
;
2230 unsigned long flags
;
2232 local_irq_save(flags
);
2234 stock
= this_cpu_ptr(&memcg_stock
);
2235 if (stock
->cached
!= memcg
) { /* reset if necessary */
2237 css_get(&memcg
->css
);
2238 stock
->cached
= memcg
;
2240 stock
->nr_pages
+= nr_pages
;
2242 if (stock
->nr_pages
> MEMCG_CHARGE_BATCH
)
2245 local_irq_restore(flags
);
2249 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2250 * of the hierarchy under it.
2252 static void drain_all_stock(struct mem_cgroup
*root_memcg
)
2256 /* If someone's already draining, avoid adding running more workers. */
2257 if (!mutex_trylock(&percpu_charge_mutex
))
2260 * Notify other cpus that system-wide "drain" is running
2261 * We do not care about races with the cpu hotplug because cpu down
2262 * as well as workers from this path always operate on the local
2263 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2266 for_each_online_cpu(cpu
) {
2267 struct memcg_stock_pcp
*stock
= &per_cpu(memcg_stock
, cpu
);
2268 struct mem_cgroup
*memcg
;
2272 memcg
= stock
->cached
;
2273 if (memcg
&& stock
->nr_pages
&&
2274 mem_cgroup_is_descendant(memcg
, root_memcg
))
2276 if (obj_stock_flush_required(stock
, root_memcg
))
2281 !test_and_set_bit(FLUSHING_CACHED_CHARGE
, &stock
->flags
)) {
2283 drain_local_stock(&stock
->work
);
2285 schedule_work_on(cpu
, &stock
->work
);
2289 mutex_unlock(&percpu_charge_mutex
);
2292 static void memcg_flush_lruvec_page_state(struct mem_cgroup
*memcg
, int cpu
)
2296 for_each_node(nid
) {
2297 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[nid
];
2298 unsigned long stat
[NR_VM_NODE_STAT_ITEMS
];
2299 struct batched_lruvec_stat
*lstatc
;
2302 lstatc
= per_cpu_ptr(pn
->lruvec_stat_cpu
, cpu
);
2303 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++) {
2304 stat
[i
] = lstatc
->count
[i
];
2305 lstatc
->count
[i
] = 0;
2309 for (i
= 0; i
< NR_VM_NODE_STAT_ITEMS
; i
++)
2310 atomic_long_add(stat
[i
], &pn
->lruvec_stat
[i
]);
2311 } while ((pn
= parent_nodeinfo(pn
, nid
)));
2315 static int memcg_hotplug_cpu_dead(unsigned int cpu
)
2317 struct memcg_stock_pcp
*stock
;
2318 struct mem_cgroup
*memcg
;
2320 stock
= &per_cpu(memcg_stock
, cpu
);
2323 for_each_mem_cgroup(memcg
)
2324 memcg_flush_lruvec_page_state(memcg
, cpu
);
2329 static unsigned long reclaim_high(struct mem_cgroup
*memcg
,
2330 unsigned int nr_pages
,
2333 unsigned long nr_reclaimed
= 0;
2336 unsigned long pflags
;
2338 if (page_counter_read(&memcg
->memory
) <=
2339 READ_ONCE(memcg
->memory
.high
))
2342 memcg_memory_event(memcg
, MEMCG_HIGH
);
2344 psi_memstall_enter(&pflags
);
2345 nr_reclaimed
+= try_to_free_mem_cgroup_pages(memcg
, nr_pages
,
2347 psi_memstall_leave(&pflags
);
2348 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2349 !mem_cgroup_is_root(memcg
));
2351 return nr_reclaimed
;
2354 static void high_work_func(struct work_struct
*work
)
2356 struct mem_cgroup
*memcg
;
2358 memcg
= container_of(work
, struct mem_cgroup
, high_work
);
2359 reclaim_high(memcg
, MEMCG_CHARGE_BATCH
, GFP_KERNEL
);
2363 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2364 * enough to still cause a significant slowdown in most cases, while still
2365 * allowing diagnostics and tracing to proceed without becoming stuck.
2367 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2370 * When calculating the delay, we use these either side of the exponentiation to
2371 * maintain precision and scale to a reasonable number of jiffies (see the table
2374 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2375 * overage ratio to a delay.
2376 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down the
2377 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2378 * to produce a reasonable delay curve.
2380 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2381 * reasonable delay curve compared to precision-adjusted overage, not
2382 * penalising heavily at first, but still making sure that growth beyond the
2383 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2384 * example, with a high of 100 megabytes:
2386 * +-------+------------------------+
2387 * | usage | time to allocate in ms |
2388 * +-------+------------------------+
2410 * +-------+------------------------+
2412 #define MEMCG_DELAY_PRECISION_SHIFT 20
2413 #define MEMCG_DELAY_SCALING_SHIFT 14
2415 static u64
calculate_overage(unsigned long usage
, unsigned long high
)
2423 * Prevent division by 0 in overage calculation by acting as if
2424 * it was a threshold of 1 page
2426 high
= max(high
, 1UL);
2428 overage
= usage
- high
;
2429 overage
<<= MEMCG_DELAY_PRECISION_SHIFT
;
2430 return div64_u64(overage
, high
);
2433 static u64
mem_find_max_overage(struct mem_cgroup
*memcg
)
2435 u64 overage
, max_overage
= 0;
2438 overage
= calculate_overage(page_counter_read(&memcg
->memory
),
2439 READ_ONCE(memcg
->memory
.high
));
2440 max_overage
= max(overage
, max_overage
);
2441 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2442 !mem_cgroup_is_root(memcg
));
2447 static u64
swap_find_max_overage(struct mem_cgroup
*memcg
)
2449 u64 overage
, max_overage
= 0;
2452 overage
= calculate_overage(page_counter_read(&memcg
->swap
),
2453 READ_ONCE(memcg
->swap
.high
));
2455 memcg_memory_event(memcg
, MEMCG_SWAP_HIGH
);
2456 max_overage
= max(overage
, max_overage
);
2457 } while ((memcg
= parent_mem_cgroup(memcg
)) &&
2458 !mem_cgroup_is_root(memcg
));
2464 * Get the number of jiffies that we should penalise a mischievous cgroup which
2465 * is exceeding its memory.high by checking both it and its ancestors.
2467 static unsigned long calculate_high_delay(struct mem_cgroup
*memcg
,
2468 unsigned int nr_pages
,
2471 unsigned long penalty_jiffies
;
2477 * We use overage compared to memory.high to calculate the number of
2478 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2479 * fairly lenient on small overages, and increasingly harsh when the
2480 * memcg in question makes it clear that it has no intention of stopping
2481 * its crazy behaviour, so we exponentially increase the delay based on
2484 penalty_jiffies
= max_overage
* max_overage
* HZ
;
2485 penalty_jiffies
>>= MEMCG_DELAY_PRECISION_SHIFT
;
2486 penalty_jiffies
>>= MEMCG_DELAY_SCALING_SHIFT
;
2489 * Factor in the task's own contribution to the overage, such that four
2490 * N-sized allocations are throttled approximately the same as one
2491 * 4N-sized allocation.
2493 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2494 * larger the current charge patch is than that.
2496 return penalty_jiffies
* nr_pages
/ MEMCG_CHARGE_BATCH
;
2500 * Scheduled by try_charge() to be executed from the userland return path
2501 * and reclaims memory over the high limit.
2503 void mem_cgroup_handle_over_high(void)
2505 unsigned long penalty_jiffies
;
2506 unsigned long pflags
;
2507 unsigned long nr_reclaimed
;
2508 unsigned int nr_pages
= current
->memcg_nr_pages_over_high
;
2509 int nr_retries
= MAX_RECLAIM_RETRIES
;
2510 struct mem_cgroup
*memcg
;
2511 bool in_retry
= false;
2513 if (likely(!nr_pages
))
2516 memcg
= get_mem_cgroup_from_mm(current
->mm
);
2517 current
->memcg_nr_pages_over_high
= 0;
2521 * The allocating task should reclaim at least the batch size, but for
2522 * subsequent retries we only want to do what's necessary to prevent oom
2523 * or breaching resource isolation.
2525 * This is distinct from memory.max or page allocator behaviour because
2526 * memory.high is currently batched, whereas memory.max and the page
2527 * allocator run every time an allocation is made.
2529 nr_reclaimed
= reclaim_high(memcg
,
2530 in_retry
? SWAP_CLUSTER_MAX
: nr_pages
,
2534 * memory.high is breached and reclaim is unable to keep up. Throttle
2535 * allocators proactively to slow down excessive growth.
2537 penalty_jiffies
= calculate_high_delay(memcg
, nr_pages
,
2538 mem_find_max_overage(memcg
));
2540 penalty_jiffies
+= calculate_high_delay(memcg
, nr_pages
,
2541 swap_find_max_overage(memcg
));
2544 * Clamp the max delay per usermode return so as to still keep the
2545 * application moving forwards and also permit diagnostics, albeit
2548 penalty_jiffies
= min(penalty_jiffies
, MEMCG_MAX_HIGH_DELAY_JIFFIES
);
2551 * Don't sleep if the amount of jiffies this memcg owes us is so low
2552 * that it's not even worth doing, in an attempt to be nice to those who
2553 * go only a small amount over their memory.high value and maybe haven't
2554 * been aggressively reclaimed enough yet.
2556 if (penalty_jiffies
<= HZ
/ 100)
2560 * If reclaim is making forward progress but we're still over
2561 * memory.high, we want to encourage that rather than doing allocator
2564 if (nr_reclaimed
|| nr_retries
--) {
2570 * If we exit early, we're guaranteed to die (since
2571 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2572 * need to account for any ill-begotten jiffies to pay them off later.
2574 psi_memstall_enter(&pflags
);
2575 schedule_timeout_killable(penalty_jiffies
);
2576 psi_memstall_leave(&pflags
);
2579 css_put(&memcg
->css
);
2582 static int try_charge_memcg(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2583 unsigned int nr_pages
)
2585 unsigned int batch
= max(MEMCG_CHARGE_BATCH
, nr_pages
);
2586 int nr_retries
= MAX_RECLAIM_RETRIES
;
2587 struct mem_cgroup
*mem_over_limit
;
2588 struct page_counter
*counter
;
2589 enum oom_status oom_status
;
2590 unsigned long nr_reclaimed
;
2591 bool may_swap
= true;
2592 bool drained
= false;
2593 unsigned long pflags
;
2596 if (consume_stock(memcg
, nr_pages
))
2599 if (!do_memsw_account() ||
2600 page_counter_try_charge(&memcg
->memsw
, batch
, &counter
)) {
2601 if (page_counter_try_charge(&memcg
->memory
, batch
, &counter
))
2603 if (do_memsw_account())
2604 page_counter_uncharge(&memcg
->memsw
, batch
);
2605 mem_over_limit
= mem_cgroup_from_counter(counter
, memory
);
2607 mem_over_limit
= mem_cgroup_from_counter(counter
, memsw
);
2611 if (batch
> nr_pages
) {
2617 * Memcg doesn't have a dedicated reserve for atomic
2618 * allocations. But like the global atomic pool, we need to
2619 * put the burden of reclaim on regular allocation requests
2620 * and let these go through as privileged allocations.
2622 if (gfp_mask
& __GFP_ATOMIC
)
2626 * Unlike in global OOM situations, memcg is not in a physical
2627 * memory shortage. Allow dying and OOM-killed tasks to
2628 * bypass the last charges so that they can exit quickly and
2629 * free their memory.
2631 if (unlikely(should_force_charge()))
2635 * Prevent unbounded recursion when reclaim operations need to
2636 * allocate memory. This might exceed the limits temporarily,
2637 * but we prefer facilitating memory reclaim and getting back
2638 * under the limit over triggering OOM kills in these cases.
2640 if (unlikely(current
->flags
& PF_MEMALLOC
))
2643 if (unlikely(task_in_memcg_oom(current
)))
2646 if (!gfpflags_allow_blocking(gfp_mask
))
2649 memcg_memory_event(mem_over_limit
, MEMCG_MAX
);
2651 psi_memstall_enter(&pflags
);
2652 nr_reclaimed
= try_to_free_mem_cgroup_pages(mem_over_limit
, nr_pages
,
2653 gfp_mask
, may_swap
);
2654 psi_memstall_leave(&pflags
);
2656 if (mem_cgroup_margin(mem_over_limit
) >= nr_pages
)
2660 drain_all_stock(mem_over_limit
);
2665 if (gfp_mask
& __GFP_NORETRY
)
2668 * Even though the limit is exceeded at this point, reclaim
2669 * may have been able to free some pages. Retry the charge
2670 * before killing the task.
2672 * Only for regular pages, though: huge pages are rather
2673 * unlikely to succeed so close to the limit, and we fall back
2674 * to regular pages anyway in case of failure.
2676 if (nr_reclaimed
&& nr_pages
<= (1 << PAGE_ALLOC_COSTLY_ORDER
))
2679 * At task move, charge accounts can be doubly counted. So, it's
2680 * better to wait until the end of task_move if something is going on.
2682 if (mem_cgroup_wait_acct_move(mem_over_limit
))
2688 if (gfp_mask
& __GFP_RETRY_MAYFAIL
)
2691 if (fatal_signal_pending(current
))
2695 * keep retrying as long as the memcg oom killer is able to make
2696 * a forward progress or bypass the charge if the oom killer
2697 * couldn't make any progress.
2699 oom_status
= mem_cgroup_oom(mem_over_limit
, gfp_mask
,
2700 get_order(nr_pages
* PAGE_SIZE
));
2701 switch (oom_status
) {
2703 nr_retries
= MAX_RECLAIM_RETRIES
;
2711 if (!(gfp_mask
& __GFP_NOFAIL
))
2715 * The allocation either can't fail or will lead to more memory
2716 * being freed very soon. Allow memory usage go over the limit
2717 * temporarily by force charging it.
2719 page_counter_charge(&memcg
->memory
, nr_pages
);
2720 if (do_memsw_account())
2721 page_counter_charge(&memcg
->memsw
, nr_pages
);
2726 if (batch
> nr_pages
)
2727 refill_stock(memcg
, batch
- nr_pages
);
2730 * If the hierarchy is above the normal consumption range, schedule
2731 * reclaim on returning to userland. We can perform reclaim here
2732 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2733 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2734 * not recorded as it most likely matches current's and won't
2735 * change in the meantime. As high limit is checked again before
2736 * reclaim, the cost of mismatch is negligible.
2739 bool mem_high
, swap_high
;
2741 mem_high
= page_counter_read(&memcg
->memory
) >
2742 READ_ONCE(memcg
->memory
.high
);
2743 swap_high
= page_counter_read(&memcg
->swap
) >
2744 READ_ONCE(memcg
->swap
.high
);
2746 /* Don't bother a random interrupted task */
2747 if (in_interrupt()) {
2749 schedule_work(&memcg
->high_work
);
2755 if (mem_high
|| swap_high
) {
2757 * The allocating tasks in this cgroup will need to do
2758 * reclaim or be throttled to prevent further growth
2759 * of the memory or swap footprints.
2761 * Target some best-effort fairness between the tasks,
2762 * and distribute reclaim work and delay penalties
2763 * based on how much each task is actually allocating.
2765 current
->memcg_nr_pages_over_high
+= batch
;
2766 set_notify_resume(current
);
2769 } while ((memcg
= parent_mem_cgroup(memcg
)));
2774 static inline int try_charge(struct mem_cgroup
*memcg
, gfp_t gfp_mask
,
2775 unsigned int nr_pages
)
2777 if (mem_cgroup_is_root(memcg
))
2780 return try_charge_memcg(memcg
, gfp_mask
, nr_pages
);
2783 #if defined(CONFIG_MEMCG_KMEM) || defined(CONFIG_MMU)
2784 static void cancel_charge(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
2786 if (mem_cgroup_is_root(memcg
))
2789 page_counter_uncharge(&memcg
->memory
, nr_pages
);
2790 if (do_memsw_account())
2791 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
2795 static void commit_charge(struct page
*page
, struct mem_cgroup
*memcg
)
2797 VM_BUG_ON_PAGE(page_memcg(page
), page
);
2799 * Any of the following ensures page's memcg stability:
2803 * - lock_page_memcg()
2804 * - exclusive reference
2806 page
->memcg_data
= (unsigned long)memcg
;
2809 static struct mem_cgroup
*get_mem_cgroup_from_objcg(struct obj_cgroup
*objcg
)
2811 struct mem_cgroup
*memcg
;
2815 memcg
= obj_cgroup_memcg(objcg
);
2816 if (unlikely(!css_tryget(&memcg
->css
)))
2823 #ifdef CONFIG_MEMCG_KMEM
2825 * The allocated objcg pointers array is not accounted directly.
2826 * Moreover, it should not come from DMA buffer and is not readily
2827 * reclaimable. So those GFP bits should be masked off.
2829 #define OBJCGS_CLEAR_MASK (__GFP_DMA | __GFP_RECLAIMABLE | __GFP_ACCOUNT)
2831 int memcg_alloc_page_obj_cgroups(struct page
*page
, struct kmem_cache
*s
,
2832 gfp_t gfp
, bool new_page
)
2834 unsigned int objects
= objs_per_slab_page(s
, page
);
2835 unsigned long memcg_data
;
2838 gfp
&= ~OBJCGS_CLEAR_MASK
;
2839 vec
= kcalloc_node(objects
, sizeof(struct obj_cgroup
*), gfp
,
2844 memcg_data
= (unsigned long) vec
| MEMCG_DATA_OBJCGS
;
2847 * If the slab page is brand new and nobody can yet access
2848 * it's memcg_data, no synchronization is required and
2849 * memcg_data can be simply assigned.
2851 page
->memcg_data
= memcg_data
;
2852 } else if (cmpxchg(&page
->memcg_data
, 0, memcg_data
)) {
2854 * If the slab page is already in use, somebody can allocate
2855 * and assign obj_cgroups in parallel. In this case the existing
2856 * objcg vector should be reused.
2862 kmemleak_not_leak(vec
);
2867 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2869 * A passed kernel object can be a slab object or a generic kernel page, so
2870 * different mechanisms for getting the memory cgroup pointer should be used.
2871 * In certain cases (e.g. kernel stacks or large kmallocs with SLUB) the caller
2872 * can not know for sure how the kernel object is implemented.
2873 * mem_cgroup_from_obj() can be safely used in such cases.
2875 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2876 * cgroup_mutex, etc.
2878 struct mem_cgroup
*mem_cgroup_from_obj(void *p
)
2882 if (mem_cgroup_disabled())
2885 page
= virt_to_head_page(p
);
2888 * Slab objects are accounted individually, not per-page.
2889 * Memcg membership data for each individual object is saved in
2890 * the page->obj_cgroups.
2892 if (page_objcgs_check(page
)) {
2893 struct obj_cgroup
*objcg
;
2896 off
= obj_to_index(page
->slab_cache
, page
, p
);
2897 objcg
= page_objcgs(page
)[off
];
2899 return obj_cgroup_memcg(objcg
);
2905 * page_memcg_check() is used here, because page_has_obj_cgroups()
2906 * check above could fail because the object cgroups vector wasn't set
2907 * at that moment, but it can be set concurrently.
2908 * page_memcg_check(page) will guarantee that a proper memory
2909 * cgroup pointer or NULL will be returned.
2911 return page_memcg_check(page
);
2914 __always_inline
struct obj_cgroup
*get_obj_cgroup_from_current(void)
2916 struct obj_cgroup
*objcg
= NULL
;
2917 struct mem_cgroup
*memcg
;
2919 if (memcg_kmem_bypass())
2923 if (unlikely(active_memcg()))
2924 memcg
= active_memcg();
2926 memcg
= mem_cgroup_from_task(current
);
2928 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
)) {
2929 objcg
= rcu_dereference(memcg
->objcg
);
2930 if (objcg
&& obj_cgroup_tryget(objcg
))
2939 static int memcg_alloc_cache_id(void)
2944 id
= ida_simple_get(&memcg_cache_ida
,
2945 0, MEMCG_CACHES_MAX_SIZE
, GFP_KERNEL
);
2949 if (id
< memcg_nr_cache_ids
)
2953 * There's no space for the new id in memcg_caches arrays,
2954 * so we have to grow them.
2956 down_write(&memcg_cache_ids_sem
);
2958 size
= 2 * (id
+ 1);
2959 if (size
< MEMCG_CACHES_MIN_SIZE
)
2960 size
= MEMCG_CACHES_MIN_SIZE
;
2961 else if (size
> MEMCG_CACHES_MAX_SIZE
)
2962 size
= MEMCG_CACHES_MAX_SIZE
;
2964 err
= memcg_update_all_list_lrus(size
);
2966 memcg_nr_cache_ids
= size
;
2968 up_write(&memcg_cache_ids_sem
);
2971 ida_simple_remove(&memcg_cache_ida
, id
);
2977 static void memcg_free_cache_id(int id
)
2979 ida_simple_remove(&memcg_cache_ida
, id
);
2983 * obj_cgroup_uncharge_pages: uncharge a number of kernel pages from a objcg
2984 * @objcg: object cgroup to uncharge
2985 * @nr_pages: number of pages to uncharge
2987 static void obj_cgroup_uncharge_pages(struct obj_cgroup
*objcg
,
2988 unsigned int nr_pages
)
2990 struct mem_cgroup
*memcg
;
2992 memcg
= get_mem_cgroup_from_objcg(objcg
);
2994 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
2995 page_counter_uncharge(&memcg
->kmem
, nr_pages
);
2996 refill_stock(memcg
, nr_pages
);
2998 css_put(&memcg
->css
);
3002 * obj_cgroup_charge_pages: charge a number of kernel pages to a objcg
3003 * @objcg: object cgroup to charge
3004 * @gfp: reclaim mode
3005 * @nr_pages: number of pages to charge
3007 * Returns 0 on success, an error code on failure.
3009 static int obj_cgroup_charge_pages(struct obj_cgroup
*objcg
, gfp_t gfp
,
3010 unsigned int nr_pages
)
3012 struct page_counter
*counter
;
3013 struct mem_cgroup
*memcg
;
3016 memcg
= get_mem_cgroup_from_objcg(objcg
);
3018 ret
= try_charge_memcg(memcg
, gfp
, nr_pages
);
3022 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) &&
3023 !page_counter_try_charge(&memcg
->kmem
, nr_pages
, &counter
)) {
3026 * Enforce __GFP_NOFAIL allocation because callers are not
3027 * prepared to see failures and likely do not have any failure
3030 if (gfp
& __GFP_NOFAIL
) {
3031 page_counter_charge(&memcg
->kmem
, nr_pages
);
3034 cancel_charge(memcg
, nr_pages
);
3038 css_put(&memcg
->css
);
3044 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
3045 * @page: page to charge
3046 * @gfp: reclaim mode
3047 * @order: allocation order
3049 * Returns 0 on success, an error code on failure.
3051 int __memcg_kmem_charge_page(struct page
*page
, gfp_t gfp
, int order
)
3053 struct obj_cgroup
*objcg
;
3056 objcg
= get_obj_cgroup_from_current();
3058 ret
= obj_cgroup_charge_pages(objcg
, gfp
, 1 << order
);
3060 page
->memcg_data
= (unsigned long)objcg
|
3064 obj_cgroup_put(objcg
);
3070 * __memcg_kmem_uncharge_page: uncharge a kmem page
3071 * @page: page to uncharge
3072 * @order: allocation order
3074 void __memcg_kmem_uncharge_page(struct page
*page
, int order
)
3076 struct obj_cgroup
*objcg
;
3077 unsigned int nr_pages
= 1 << order
;
3079 if (!PageMemcgKmem(page
))
3082 objcg
= __page_objcg(page
);
3083 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
3084 page
->memcg_data
= 0;
3085 obj_cgroup_put(objcg
);
3088 void mod_objcg_state(struct obj_cgroup
*objcg
, struct pglist_data
*pgdat
,
3089 enum node_stat_item idx
, int nr
)
3091 unsigned long flags
;
3092 struct obj_stock
*stock
= get_obj_stock(&flags
);
3096 * Save vmstat data in stock and skip vmstat array update unless
3097 * accumulating over a page of vmstat data or when pgdat or idx
3100 if (stock
->cached_objcg
!= objcg
) {
3101 drain_obj_stock(stock
);
3102 obj_cgroup_get(objcg
);
3103 stock
->nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
)
3104 ? atomic_xchg(&objcg
->nr_charged_bytes
, 0) : 0;
3105 stock
->cached_objcg
= objcg
;
3106 stock
->cached_pgdat
= pgdat
;
3107 } else if (stock
->cached_pgdat
!= pgdat
) {
3108 /* Flush the existing cached vmstat data */
3109 if (stock
->nr_slab_reclaimable_b
) {
3110 mod_objcg_mlstate(objcg
, pgdat
, NR_SLAB_RECLAIMABLE_B
,
3111 stock
->nr_slab_reclaimable_b
);
3112 stock
->nr_slab_reclaimable_b
= 0;
3114 if (stock
->nr_slab_unreclaimable_b
) {
3115 mod_objcg_mlstate(objcg
, pgdat
, NR_SLAB_UNRECLAIMABLE_B
,
3116 stock
->nr_slab_unreclaimable_b
);
3117 stock
->nr_slab_unreclaimable_b
= 0;
3119 stock
->cached_pgdat
= pgdat
;
3122 bytes
= (idx
== NR_SLAB_RECLAIMABLE_B
) ? &stock
->nr_slab_reclaimable_b
3123 : &stock
->nr_slab_unreclaimable_b
;
3125 * Even for large object >= PAGE_SIZE, the vmstat data will still be
3126 * cached locally at least once before pushing it out.
3133 if (abs(*bytes
) > PAGE_SIZE
) {
3141 mod_objcg_mlstate(objcg
, pgdat
, idx
, nr
);
3143 put_obj_stock(flags
);
3146 static bool consume_obj_stock(struct obj_cgroup
*objcg
, unsigned int nr_bytes
)
3148 unsigned long flags
;
3149 struct obj_stock
*stock
= get_obj_stock(&flags
);
3152 if (objcg
== stock
->cached_objcg
&& stock
->nr_bytes
>= nr_bytes
) {
3153 stock
->nr_bytes
-= nr_bytes
;
3157 put_obj_stock(flags
);
3162 static void drain_obj_stock(struct obj_stock
*stock
)
3164 struct obj_cgroup
*old
= stock
->cached_objcg
;
3169 if (stock
->nr_bytes
) {
3170 unsigned int nr_pages
= stock
->nr_bytes
>> PAGE_SHIFT
;
3171 unsigned int nr_bytes
= stock
->nr_bytes
& (PAGE_SIZE
- 1);
3174 obj_cgroup_uncharge_pages(old
, nr_pages
);
3177 * The leftover is flushed to the centralized per-memcg value.
3178 * On the next attempt to refill obj stock it will be moved
3179 * to a per-cpu stock (probably, on an other CPU), see
3180 * refill_obj_stock().
3182 * How often it's flushed is a trade-off between the memory
3183 * limit enforcement accuracy and potential CPU contention,
3184 * so it might be changed in the future.
3186 atomic_add(nr_bytes
, &old
->nr_charged_bytes
);
3187 stock
->nr_bytes
= 0;
3191 * Flush the vmstat data in current stock
3193 if (stock
->nr_slab_reclaimable_b
|| stock
->nr_slab_unreclaimable_b
) {
3194 if (stock
->nr_slab_reclaimable_b
) {
3195 mod_objcg_mlstate(old
, stock
->cached_pgdat
,
3196 NR_SLAB_RECLAIMABLE_B
,
3197 stock
->nr_slab_reclaimable_b
);
3198 stock
->nr_slab_reclaimable_b
= 0;
3200 if (stock
->nr_slab_unreclaimable_b
) {
3201 mod_objcg_mlstate(old
, stock
->cached_pgdat
,
3202 NR_SLAB_UNRECLAIMABLE_B
,
3203 stock
->nr_slab_unreclaimable_b
);
3204 stock
->nr_slab_unreclaimable_b
= 0;
3206 stock
->cached_pgdat
= NULL
;
3209 obj_cgroup_put(old
);
3210 stock
->cached_objcg
= NULL
;
3213 static bool obj_stock_flush_required(struct memcg_stock_pcp
*stock
,
3214 struct mem_cgroup
*root_memcg
)
3216 struct mem_cgroup
*memcg
;
3218 if (in_task() && stock
->task_obj
.cached_objcg
) {
3219 memcg
= obj_cgroup_memcg(stock
->task_obj
.cached_objcg
);
3220 if (memcg
&& mem_cgroup_is_descendant(memcg
, root_memcg
))
3223 if (stock
->irq_obj
.cached_objcg
) {
3224 memcg
= obj_cgroup_memcg(stock
->irq_obj
.cached_objcg
);
3225 if (memcg
&& mem_cgroup_is_descendant(memcg
, root_memcg
))
3232 static void refill_obj_stock(struct obj_cgroup
*objcg
, unsigned int nr_bytes
,
3233 bool allow_uncharge
)
3235 unsigned long flags
;
3236 struct obj_stock
*stock
= get_obj_stock(&flags
);
3237 unsigned int nr_pages
= 0;
3239 if (stock
->cached_objcg
!= objcg
) { /* reset if necessary */
3240 drain_obj_stock(stock
);
3241 obj_cgroup_get(objcg
);
3242 stock
->cached_objcg
= objcg
;
3243 stock
->nr_bytes
= atomic_read(&objcg
->nr_charged_bytes
)
3244 ? atomic_xchg(&objcg
->nr_charged_bytes
, 0) : 0;
3245 allow_uncharge
= true; /* Allow uncharge when objcg changes */
3247 stock
->nr_bytes
+= nr_bytes
;
3249 if (allow_uncharge
&& (stock
->nr_bytes
> PAGE_SIZE
)) {
3250 nr_pages
= stock
->nr_bytes
>> PAGE_SHIFT
;
3251 stock
->nr_bytes
&= (PAGE_SIZE
- 1);
3254 put_obj_stock(flags
);
3257 obj_cgroup_uncharge_pages(objcg
, nr_pages
);
3260 int obj_cgroup_charge(struct obj_cgroup
*objcg
, gfp_t gfp
, size_t size
)
3262 unsigned int nr_pages
, nr_bytes
;
3265 if (consume_obj_stock(objcg
, size
))
3269 * In theory, objcg->nr_charged_bytes can have enough
3270 * pre-charged bytes to satisfy the allocation. However,
3271 * flushing objcg->nr_charged_bytes requires two atomic
3272 * operations, and objcg->nr_charged_bytes can't be big.
3273 * The shared objcg->nr_charged_bytes can also become a
3274 * performance bottleneck if all tasks of the same memcg are
3275 * trying to update it. So it's better to ignore it and try
3276 * grab some new pages. The stock's nr_bytes will be flushed to
3277 * objcg->nr_charged_bytes later on when objcg changes.
3279 * The stock's nr_bytes may contain enough pre-charged bytes
3280 * to allow one less page from being charged, but we can't rely
3281 * on the pre-charged bytes not being changed outside of
3282 * consume_obj_stock() or refill_obj_stock(). So ignore those
3283 * pre-charged bytes as well when charging pages. To avoid a
3284 * page uncharge right after a page charge, we set the
3285 * allow_uncharge flag to false when calling refill_obj_stock()
3286 * to temporarily allow the pre-charged bytes to exceed the page
3287 * size limit. The maximum reachable value of the pre-charged
3288 * bytes is (sizeof(object) + PAGE_SIZE - 2) if there is no data
3291 nr_pages
= size
>> PAGE_SHIFT
;
3292 nr_bytes
= size
& (PAGE_SIZE
- 1);
3297 ret
= obj_cgroup_charge_pages(objcg
, gfp
, nr_pages
);
3298 if (!ret
&& nr_bytes
)
3299 refill_obj_stock(objcg
, PAGE_SIZE
- nr_bytes
, false);
3304 void obj_cgroup_uncharge(struct obj_cgroup
*objcg
, size_t size
)
3306 refill_obj_stock(objcg
, size
, true);
3309 #endif /* CONFIG_MEMCG_KMEM */
3312 * Because page_memcg(head) is not set on tails, set it now.
3314 void split_page_memcg(struct page
*head
, unsigned int nr
)
3316 struct mem_cgroup
*memcg
= page_memcg(head
);
3319 if (mem_cgroup_disabled() || !memcg
)
3322 for (i
= 1; i
< nr
; i
++)
3323 head
[i
].memcg_data
= head
->memcg_data
;
3325 if (PageMemcgKmem(head
))
3326 obj_cgroup_get_many(__page_objcg(head
), nr
- 1);
3328 css_get_many(&memcg
->css
, nr
- 1);
3331 #ifdef CONFIG_MEMCG_SWAP
3333 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3334 * @entry: swap entry to be moved
3335 * @from: mem_cgroup which the entry is moved from
3336 * @to: mem_cgroup which the entry is moved to
3338 * It succeeds only when the swap_cgroup's record for this entry is the same
3339 * as the mem_cgroup's id of @from.
3341 * Returns 0 on success, -EINVAL on failure.
3343 * The caller must have charged to @to, IOW, called page_counter_charge() about
3344 * both res and memsw, and called css_get().
3346 static int mem_cgroup_move_swap_account(swp_entry_t entry
,
3347 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3349 unsigned short old_id
, new_id
;
3351 old_id
= mem_cgroup_id(from
);
3352 new_id
= mem_cgroup_id(to
);
3354 if (swap_cgroup_cmpxchg(entry
, old_id
, new_id
) == old_id
) {
3355 mod_memcg_state(from
, MEMCG_SWAP
, -1);
3356 mod_memcg_state(to
, MEMCG_SWAP
, 1);
3362 static inline int mem_cgroup_move_swap_account(swp_entry_t entry
,
3363 struct mem_cgroup
*from
, struct mem_cgroup
*to
)
3369 static DEFINE_MUTEX(memcg_max_mutex
);
3371 static int mem_cgroup_resize_max(struct mem_cgroup
*memcg
,
3372 unsigned long max
, bool memsw
)
3374 bool enlarge
= false;
3375 bool drained
= false;
3377 bool limits_invariant
;
3378 struct page_counter
*counter
= memsw
? &memcg
->memsw
: &memcg
->memory
;
3381 if (signal_pending(current
)) {
3386 mutex_lock(&memcg_max_mutex
);
3388 * Make sure that the new limit (memsw or memory limit) doesn't
3389 * break our basic invariant rule memory.max <= memsw.max.
3391 limits_invariant
= memsw
? max
>= READ_ONCE(memcg
->memory
.max
) :
3392 max
<= memcg
->memsw
.max
;
3393 if (!limits_invariant
) {
3394 mutex_unlock(&memcg_max_mutex
);
3398 if (max
> counter
->max
)
3400 ret
= page_counter_set_max(counter
, max
);
3401 mutex_unlock(&memcg_max_mutex
);
3407 drain_all_stock(memcg
);
3412 if (!try_to_free_mem_cgroup_pages(memcg
, 1,
3413 GFP_KERNEL
, !memsw
)) {
3419 if (!ret
&& enlarge
)
3420 memcg_oom_recover(memcg
);
3425 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t
*pgdat
, int order
,
3427 unsigned long *total_scanned
)
3429 unsigned long nr_reclaimed
= 0;
3430 struct mem_cgroup_per_node
*mz
, *next_mz
= NULL
;
3431 unsigned long reclaimed
;
3433 struct mem_cgroup_tree_per_node
*mctz
;
3434 unsigned long excess
;
3435 unsigned long nr_scanned
;
3440 mctz
= soft_limit_tree_node(pgdat
->node_id
);
3443 * Do not even bother to check the largest node if the root
3444 * is empty. Do it lockless to prevent lock bouncing. Races
3445 * are acceptable as soft limit is best effort anyway.
3447 if (!mctz
|| RB_EMPTY_ROOT(&mctz
->rb_root
))
3451 * This loop can run a while, specially if mem_cgroup's continuously
3452 * keep exceeding their soft limit and putting the system under
3459 mz
= mem_cgroup_largest_soft_limit_node(mctz
);
3464 reclaimed
= mem_cgroup_soft_reclaim(mz
->memcg
, pgdat
,
3465 gfp_mask
, &nr_scanned
);
3466 nr_reclaimed
+= reclaimed
;
3467 *total_scanned
+= nr_scanned
;
3468 spin_lock_irq(&mctz
->lock
);
3469 __mem_cgroup_remove_exceeded(mz
, mctz
);
3472 * If we failed to reclaim anything from this memory cgroup
3473 * it is time to move on to the next cgroup
3477 next_mz
= __mem_cgroup_largest_soft_limit_node(mctz
);
3479 excess
= soft_limit_excess(mz
->memcg
);
3481 * One school of thought says that we should not add
3482 * back the node to the tree if reclaim returns 0.
3483 * But our reclaim could return 0, simply because due
3484 * to priority we are exposing a smaller subset of
3485 * memory to reclaim from. Consider this as a longer
3488 /* If excess == 0, no tree ops */
3489 __mem_cgroup_insert_exceeded(mz
, mctz
, excess
);
3490 spin_unlock_irq(&mctz
->lock
);
3491 css_put(&mz
->memcg
->css
);
3494 * Could not reclaim anything and there are no more
3495 * mem cgroups to try or we seem to be looping without
3496 * reclaiming anything.
3498 if (!nr_reclaimed
&&
3500 loop
> MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS
))
3502 } while (!nr_reclaimed
);
3504 css_put(&next_mz
->memcg
->css
);
3505 return nr_reclaimed
;
3509 * Reclaims as many pages from the given memcg as possible.
3511 * Caller is responsible for holding css reference for memcg.
3513 static int mem_cgroup_force_empty(struct mem_cgroup
*memcg
)
3515 int nr_retries
= MAX_RECLAIM_RETRIES
;
3517 /* we call try-to-free pages for make this cgroup empty */
3518 lru_add_drain_all();
3520 drain_all_stock(memcg
);
3522 /* try to free all pages in this cgroup */
3523 while (nr_retries
&& page_counter_read(&memcg
->memory
)) {
3526 if (signal_pending(current
))
3529 progress
= try_to_free_mem_cgroup_pages(memcg
, 1,
3533 /* maybe some writeback is necessary */
3534 congestion_wait(BLK_RW_ASYNC
, HZ
/10);
3542 static ssize_t
mem_cgroup_force_empty_write(struct kernfs_open_file
*of
,
3543 char *buf
, size_t nbytes
,
3546 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3548 if (mem_cgroup_is_root(memcg
))
3550 return mem_cgroup_force_empty(memcg
) ?: nbytes
;
3553 static u64
mem_cgroup_hierarchy_read(struct cgroup_subsys_state
*css
,
3559 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state
*css
,
3560 struct cftype
*cft
, u64 val
)
3565 pr_warn_once("Non-hierarchical mode is deprecated. "
3566 "Please report your usecase to linux-mm@kvack.org if you "
3567 "depend on this functionality.\n");
3572 static unsigned long mem_cgroup_usage(struct mem_cgroup
*memcg
, bool swap
)
3576 if (mem_cgroup_is_root(memcg
)) {
3577 cgroup_rstat_flush(memcg
->css
.cgroup
);
3578 val
= memcg_page_state(memcg
, NR_FILE_PAGES
) +
3579 memcg_page_state(memcg
, NR_ANON_MAPPED
);
3581 val
+= memcg_page_state(memcg
, MEMCG_SWAP
);
3584 val
= page_counter_read(&memcg
->memory
);
3586 val
= page_counter_read(&memcg
->memsw
);
3599 static u64
mem_cgroup_read_u64(struct cgroup_subsys_state
*css
,
3602 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3603 struct page_counter
*counter
;
3605 switch (MEMFILE_TYPE(cft
->private)) {
3607 counter
= &memcg
->memory
;
3610 counter
= &memcg
->memsw
;
3613 counter
= &memcg
->kmem
;
3616 counter
= &memcg
->tcpmem
;
3622 switch (MEMFILE_ATTR(cft
->private)) {
3624 if (counter
== &memcg
->memory
)
3625 return (u64
)mem_cgroup_usage(memcg
, false) * PAGE_SIZE
;
3626 if (counter
== &memcg
->memsw
)
3627 return (u64
)mem_cgroup_usage(memcg
, true) * PAGE_SIZE
;
3628 return (u64
)page_counter_read(counter
) * PAGE_SIZE
;
3630 return (u64
)counter
->max
* PAGE_SIZE
;
3632 return (u64
)counter
->watermark
* PAGE_SIZE
;
3634 return counter
->failcnt
;
3635 case RES_SOFT_LIMIT
:
3636 return (u64
)memcg
->soft_limit
* PAGE_SIZE
;
3642 #ifdef CONFIG_MEMCG_KMEM
3643 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3645 struct obj_cgroup
*objcg
;
3648 if (cgroup_memory_nokmem
)
3651 BUG_ON(memcg
->kmemcg_id
>= 0);
3652 BUG_ON(memcg
->kmem_state
);
3654 memcg_id
= memcg_alloc_cache_id();
3658 objcg
= obj_cgroup_alloc();
3660 memcg_free_cache_id(memcg_id
);
3663 objcg
->memcg
= memcg
;
3664 rcu_assign_pointer(memcg
->objcg
, objcg
);
3666 static_branch_enable(&memcg_kmem_enabled_key
);
3668 memcg
->kmemcg_id
= memcg_id
;
3669 memcg
->kmem_state
= KMEM_ONLINE
;
3674 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3676 struct cgroup_subsys_state
*css
;
3677 struct mem_cgroup
*parent
, *child
;
3680 if (memcg
->kmem_state
!= KMEM_ONLINE
)
3683 memcg
->kmem_state
= KMEM_ALLOCATED
;
3685 parent
= parent_mem_cgroup(memcg
);
3687 parent
= root_mem_cgroup
;
3689 memcg_reparent_objcgs(memcg
, parent
);
3691 kmemcg_id
= memcg
->kmemcg_id
;
3692 BUG_ON(kmemcg_id
< 0);
3695 * Change kmemcg_id of this cgroup and all its descendants to the
3696 * parent's id, and then move all entries from this cgroup's list_lrus
3697 * to ones of the parent. After we have finished, all list_lrus
3698 * corresponding to this cgroup are guaranteed to remain empty. The
3699 * ordering is imposed by list_lru_node->lock taken by
3700 * memcg_drain_all_list_lrus().
3702 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3703 css_for_each_descendant_pre(css
, &memcg
->css
) {
3704 child
= mem_cgroup_from_css(css
);
3705 BUG_ON(child
->kmemcg_id
!= kmemcg_id
);
3706 child
->kmemcg_id
= parent
->kmemcg_id
;
3710 memcg_drain_all_list_lrus(kmemcg_id
, parent
);
3712 memcg_free_cache_id(kmemcg_id
);
3715 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3717 /* css_alloc() failed, offlining didn't happen */
3718 if (unlikely(memcg
->kmem_state
== KMEM_ONLINE
))
3719 memcg_offline_kmem(memcg
);
3722 static int memcg_online_kmem(struct mem_cgroup
*memcg
)
3726 static void memcg_offline_kmem(struct mem_cgroup
*memcg
)
3729 static void memcg_free_kmem(struct mem_cgroup
*memcg
)
3732 #endif /* CONFIG_MEMCG_KMEM */
3734 static int memcg_update_kmem_max(struct mem_cgroup
*memcg
,
3739 mutex_lock(&memcg_max_mutex
);
3740 ret
= page_counter_set_max(&memcg
->kmem
, max
);
3741 mutex_unlock(&memcg_max_mutex
);
3745 static int memcg_update_tcp_max(struct mem_cgroup
*memcg
, unsigned long max
)
3749 mutex_lock(&memcg_max_mutex
);
3751 ret
= page_counter_set_max(&memcg
->tcpmem
, max
);
3755 if (!memcg
->tcpmem_active
) {
3757 * The active flag needs to be written after the static_key
3758 * update. This is what guarantees that the socket activation
3759 * function is the last one to run. See mem_cgroup_sk_alloc()
3760 * for details, and note that we don't mark any socket as
3761 * belonging to this memcg until that flag is up.
3763 * We need to do this, because static_keys will span multiple
3764 * sites, but we can't control their order. If we mark a socket
3765 * as accounted, but the accounting functions are not patched in
3766 * yet, we'll lose accounting.
3768 * We never race with the readers in mem_cgroup_sk_alloc(),
3769 * because when this value change, the code to process it is not
3772 static_branch_inc(&memcg_sockets_enabled_key
);
3773 memcg
->tcpmem_active
= true;
3776 mutex_unlock(&memcg_max_mutex
);
3781 * The user of this function is...
3784 static ssize_t
mem_cgroup_write(struct kernfs_open_file
*of
,
3785 char *buf
, size_t nbytes
, loff_t off
)
3787 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3788 unsigned long nr_pages
;
3791 buf
= strstrip(buf
);
3792 ret
= page_counter_memparse(buf
, "-1", &nr_pages
);
3796 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3798 if (mem_cgroup_is_root(memcg
)) { /* Can't set limit on root */
3802 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3804 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, false);
3807 ret
= mem_cgroup_resize_max(memcg
, nr_pages
, true);
3810 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3811 "Please report your usecase to linux-mm@kvack.org if you "
3812 "depend on this functionality.\n");
3813 ret
= memcg_update_kmem_max(memcg
, nr_pages
);
3816 ret
= memcg_update_tcp_max(memcg
, nr_pages
);
3820 case RES_SOFT_LIMIT
:
3821 memcg
->soft_limit
= nr_pages
;
3825 return ret
?: nbytes
;
3828 static ssize_t
mem_cgroup_reset(struct kernfs_open_file
*of
, char *buf
,
3829 size_t nbytes
, loff_t off
)
3831 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
3832 struct page_counter
*counter
;
3834 switch (MEMFILE_TYPE(of_cft(of
)->private)) {
3836 counter
= &memcg
->memory
;
3839 counter
= &memcg
->memsw
;
3842 counter
= &memcg
->kmem
;
3845 counter
= &memcg
->tcpmem
;
3851 switch (MEMFILE_ATTR(of_cft(of
)->private)) {
3853 page_counter_reset_watermark(counter
);
3856 counter
->failcnt
= 0;
3865 static u64
mem_cgroup_move_charge_read(struct cgroup_subsys_state
*css
,
3868 return mem_cgroup_from_css(css
)->move_charge_at_immigrate
;
3872 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3873 struct cftype
*cft
, u64 val
)
3875 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
3877 if (val
& ~MOVE_MASK
)
3881 * No kind of locking is needed in here, because ->can_attach() will
3882 * check this value once in the beginning of the process, and then carry
3883 * on with stale data. This means that changes to this value will only
3884 * affect task migrations starting after the change.
3886 memcg
->move_charge_at_immigrate
= val
;
3890 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state
*css
,
3891 struct cftype
*cft
, u64 val
)
3899 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3900 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3901 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3903 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup
*memcg
,
3904 int nid
, unsigned int lru_mask
, bool tree
)
3906 struct lruvec
*lruvec
= mem_cgroup_lruvec(memcg
, NODE_DATA(nid
));
3907 unsigned long nr
= 0;
3910 VM_BUG_ON((unsigned)nid
>= nr_node_ids
);
3913 if (!(BIT(lru
) & lru_mask
))
3916 nr
+= lruvec_page_state(lruvec
, NR_LRU_BASE
+ lru
);
3918 nr
+= lruvec_page_state_local(lruvec
, NR_LRU_BASE
+ lru
);
3923 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup
*memcg
,
3924 unsigned int lru_mask
,
3927 unsigned long nr
= 0;
3931 if (!(BIT(lru
) & lru_mask
))
3934 nr
+= memcg_page_state(memcg
, NR_LRU_BASE
+ lru
);
3936 nr
+= memcg_page_state_local(memcg
, NR_LRU_BASE
+ lru
);
3941 static int memcg_numa_stat_show(struct seq_file
*m
, void *v
)
3945 unsigned int lru_mask
;
3948 static const struct numa_stat stats
[] = {
3949 { "total", LRU_ALL
},
3950 { "file", LRU_ALL_FILE
},
3951 { "anon", LRU_ALL_ANON
},
3952 { "unevictable", BIT(LRU_UNEVICTABLE
) },
3954 const struct numa_stat
*stat
;
3956 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
3958 cgroup_rstat_flush(memcg
->css
.cgroup
);
3960 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3961 seq_printf(m
, "%s=%lu", stat
->name
,
3962 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3964 for_each_node_state(nid
, N_MEMORY
)
3965 seq_printf(m
, " N%d=%lu", nid
,
3966 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3967 stat
->lru_mask
, false));
3971 for (stat
= stats
; stat
< stats
+ ARRAY_SIZE(stats
); stat
++) {
3973 seq_printf(m
, "hierarchical_%s=%lu", stat
->name
,
3974 mem_cgroup_nr_lru_pages(memcg
, stat
->lru_mask
,
3976 for_each_node_state(nid
, N_MEMORY
)
3977 seq_printf(m
, " N%d=%lu", nid
,
3978 mem_cgroup_node_nr_lru_pages(memcg
, nid
,
3979 stat
->lru_mask
, true));
3985 #endif /* CONFIG_NUMA */
3987 static const unsigned int memcg1_stats
[] = {
3990 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4000 static const char *const memcg1_stat_names
[] = {
4003 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4013 /* Universal VM events cgroup1 shows, original sort order */
4014 static const unsigned int memcg1_events
[] = {
4021 static int memcg_stat_show(struct seq_file
*m
, void *v
)
4023 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
4024 unsigned long memory
, memsw
;
4025 struct mem_cgroup
*mi
;
4028 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names
) != ARRAY_SIZE(memcg1_stats
));
4030 cgroup_rstat_flush(memcg
->css
.cgroup
);
4032 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
4035 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
4037 nr
= memcg_page_state_local(memcg
, memcg1_stats
[i
]);
4038 seq_printf(m
, "%s %lu\n", memcg1_stat_names
[i
], nr
* PAGE_SIZE
);
4041 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
4042 seq_printf(m
, "%s %lu\n", vm_event_name(memcg1_events
[i
]),
4043 memcg_events_local(memcg
, memcg1_events
[i
]));
4045 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
4046 seq_printf(m
, "%s %lu\n", lru_list_name(i
),
4047 memcg_page_state_local(memcg
, NR_LRU_BASE
+ i
) *
4050 /* Hierarchical information */
4051 memory
= memsw
= PAGE_COUNTER_MAX
;
4052 for (mi
= memcg
; mi
; mi
= parent_mem_cgroup(mi
)) {
4053 memory
= min(memory
, READ_ONCE(mi
->memory
.max
));
4054 memsw
= min(memsw
, READ_ONCE(mi
->memsw
.max
));
4056 seq_printf(m
, "hierarchical_memory_limit %llu\n",
4057 (u64
)memory
* PAGE_SIZE
);
4058 if (do_memsw_account())
4059 seq_printf(m
, "hierarchical_memsw_limit %llu\n",
4060 (u64
)memsw
* PAGE_SIZE
);
4062 for (i
= 0; i
< ARRAY_SIZE(memcg1_stats
); i
++) {
4065 if (memcg1_stats
[i
] == MEMCG_SWAP
&& !do_memsw_account())
4067 nr
= memcg_page_state(memcg
, memcg1_stats
[i
]);
4068 seq_printf(m
, "total_%s %llu\n", memcg1_stat_names
[i
],
4069 (u64
)nr
* PAGE_SIZE
);
4072 for (i
= 0; i
< ARRAY_SIZE(memcg1_events
); i
++)
4073 seq_printf(m
, "total_%s %llu\n",
4074 vm_event_name(memcg1_events
[i
]),
4075 (u64
)memcg_events(memcg
, memcg1_events
[i
]));
4077 for (i
= 0; i
< NR_LRU_LISTS
; i
++)
4078 seq_printf(m
, "total_%s %llu\n", lru_list_name(i
),
4079 (u64
)memcg_page_state(memcg
, NR_LRU_BASE
+ i
) *
4082 #ifdef CONFIG_DEBUG_VM
4085 struct mem_cgroup_per_node
*mz
;
4086 unsigned long anon_cost
= 0;
4087 unsigned long file_cost
= 0;
4089 for_each_online_pgdat(pgdat
) {
4090 mz
= memcg
->nodeinfo
[pgdat
->node_id
];
4092 anon_cost
+= mz
->lruvec
.anon_cost
;
4093 file_cost
+= mz
->lruvec
.file_cost
;
4095 seq_printf(m
, "anon_cost %lu\n", anon_cost
);
4096 seq_printf(m
, "file_cost %lu\n", file_cost
);
4103 static u64
mem_cgroup_swappiness_read(struct cgroup_subsys_state
*css
,
4106 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4108 return mem_cgroup_swappiness(memcg
);
4111 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state
*css
,
4112 struct cftype
*cft
, u64 val
)
4114 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4119 if (!mem_cgroup_is_root(memcg
))
4120 memcg
->swappiness
= val
;
4122 vm_swappiness
= val
;
4127 static void __mem_cgroup_threshold(struct mem_cgroup
*memcg
, bool swap
)
4129 struct mem_cgroup_threshold_ary
*t
;
4130 unsigned long usage
;
4135 t
= rcu_dereference(memcg
->thresholds
.primary
);
4137 t
= rcu_dereference(memcg
->memsw_thresholds
.primary
);
4142 usage
= mem_cgroup_usage(memcg
, swap
);
4145 * current_threshold points to threshold just below or equal to usage.
4146 * If it's not true, a threshold was crossed after last
4147 * call of __mem_cgroup_threshold().
4149 i
= t
->current_threshold
;
4152 * Iterate backward over array of thresholds starting from
4153 * current_threshold and check if a threshold is crossed.
4154 * If none of thresholds below usage is crossed, we read
4155 * only one element of the array here.
4157 for (; i
>= 0 && unlikely(t
->entries
[i
].threshold
> usage
); i
--)
4158 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4160 /* i = current_threshold + 1 */
4164 * Iterate forward over array of thresholds starting from
4165 * current_threshold+1 and check if a threshold is crossed.
4166 * If none of thresholds above usage is crossed, we read
4167 * only one element of the array here.
4169 for (; i
< t
->size
&& unlikely(t
->entries
[i
].threshold
<= usage
); i
++)
4170 eventfd_signal(t
->entries
[i
].eventfd
, 1);
4172 /* Update current_threshold */
4173 t
->current_threshold
= i
- 1;
4178 static void mem_cgroup_threshold(struct mem_cgroup
*memcg
)
4181 __mem_cgroup_threshold(memcg
, false);
4182 if (do_memsw_account())
4183 __mem_cgroup_threshold(memcg
, true);
4185 memcg
= parent_mem_cgroup(memcg
);
4189 static int compare_thresholds(const void *a
, const void *b
)
4191 const struct mem_cgroup_threshold
*_a
= a
;
4192 const struct mem_cgroup_threshold
*_b
= b
;
4194 if (_a
->threshold
> _b
->threshold
)
4197 if (_a
->threshold
< _b
->threshold
)
4203 static int mem_cgroup_oom_notify_cb(struct mem_cgroup
*memcg
)
4205 struct mem_cgroup_eventfd_list
*ev
;
4207 spin_lock(&memcg_oom_lock
);
4209 list_for_each_entry(ev
, &memcg
->oom_notify
, list
)
4210 eventfd_signal(ev
->eventfd
, 1);
4212 spin_unlock(&memcg_oom_lock
);
4216 static void mem_cgroup_oom_notify(struct mem_cgroup
*memcg
)
4218 struct mem_cgroup
*iter
;
4220 for_each_mem_cgroup_tree(iter
, memcg
)
4221 mem_cgroup_oom_notify_cb(iter
);
4224 static int __mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4225 struct eventfd_ctx
*eventfd
, const char *args
, enum res_type type
)
4227 struct mem_cgroup_thresholds
*thresholds
;
4228 struct mem_cgroup_threshold_ary
*new;
4229 unsigned long threshold
;
4230 unsigned long usage
;
4233 ret
= page_counter_memparse(args
, "-1", &threshold
);
4237 mutex_lock(&memcg
->thresholds_lock
);
4240 thresholds
= &memcg
->thresholds
;
4241 usage
= mem_cgroup_usage(memcg
, false);
4242 } else if (type
== _MEMSWAP
) {
4243 thresholds
= &memcg
->memsw_thresholds
;
4244 usage
= mem_cgroup_usage(memcg
, true);
4248 /* Check if a threshold crossed before adding a new one */
4249 if (thresholds
->primary
)
4250 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4252 size
= thresholds
->primary
? thresholds
->primary
->size
+ 1 : 1;
4254 /* Allocate memory for new array of thresholds */
4255 new = kmalloc(struct_size(new, entries
, size
), GFP_KERNEL
);
4262 /* Copy thresholds (if any) to new array */
4263 if (thresholds
->primary
)
4264 memcpy(new->entries
, thresholds
->primary
->entries
,
4265 flex_array_size(new, entries
, size
- 1));
4267 /* Add new threshold */
4268 new->entries
[size
- 1].eventfd
= eventfd
;
4269 new->entries
[size
- 1].threshold
= threshold
;
4271 /* Sort thresholds. Registering of new threshold isn't time-critical */
4272 sort(new->entries
, size
, sizeof(*new->entries
),
4273 compare_thresholds
, NULL
);
4275 /* Find current threshold */
4276 new->current_threshold
= -1;
4277 for (i
= 0; i
< size
; i
++) {
4278 if (new->entries
[i
].threshold
<= usage
) {
4280 * new->current_threshold will not be used until
4281 * rcu_assign_pointer(), so it's safe to increment
4284 ++new->current_threshold
;
4289 /* Free old spare buffer and save old primary buffer as spare */
4290 kfree(thresholds
->spare
);
4291 thresholds
->spare
= thresholds
->primary
;
4293 rcu_assign_pointer(thresholds
->primary
, new);
4295 /* To be sure that nobody uses thresholds */
4299 mutex_unlock(&memcg
->thresholds_lock
);
4304 static int mem_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4305 struct eventfd_ctx
*eventfd
, const char *args
)
4307 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEM
);
4310 static int memsw_cgroup_usage_register_event(struct mem_cgroup
*memcg
,
4311 struct eventfd_ctx
*eventfd
, const char *args
)
4313 return __mem_cgroup_usage_register_event(memcg
, eventfd
, args
, _MEMSWAP
);
4316 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4317 struct eventfd_ctx
*eventfd
, enum res_type type
)
4319 struct mem_cgroup_thresholds
*thresholds
;
4320 struct mem_cgroup_threshold_ary
*new;
4321 unsigned long usage
;
4322 int i
, j
, size
, entries
;
4324 mutex_lock(&memcg
->thresholds_lock
);
4327 thresholds
= &memcg
->thresholds
;
4328 usage
= mem_cgroup_usage(memcg
, false);
4329 } else if (type
== _MEMSWAP
) {
4330 thresholds
= &memcg
->memsw_thresholds
;
4331 usage
= mem_cgroup_usage(memcg
, true);
4335 if (!thresholds
->primary
)
4338 /* Check if a threshold crossed before removing */
4339 __mem_cgroup_threshold(memcg
, type
== _MEMSWAP
);
4341 /* Calculate new number of threshold */
4343 for (i
= 0; i
< thresholds
->primary
->size
; i
++) {
4344 if (thresholds
->primary
->entries
[i
].eventfd
!= eventfd
)
4350 new = thresholds
->spare
;
4352 /* If no items related to eventfd have been cleared, nothing to do */
4356 /* Set thresholds array to NULL if we don't have thresholds */
4365 /* Copy thresholds and find current threshold */
4366 new->current_threshold
= -1;
4367 for (i
= 0, j
= 0; i
< thresholds
->primary
->size
; i
++) {
4368 if (thresholds
->primary
->entries
[i
].eventfd
== eventfd
)
4371 new->entries
[j
] = thresholds
->primary
->entries
[i
];
4372 if (new->entries
[j
].threshold
<= usage
) {
4374 * new->current_threshold will not be used
4375 * until rcu_assign_pointer(), so it's safe to increment
4378 ++new->current_threshold
;
4384 /* Swap primary and spare array */
4385 thresholds
->spare
= thresholds
->primary
;
4387 rcu_assign_pointer(thresholds
->primary
, new);
4389 /* To be sure that nobody uses thresholds */
4392 /* If all events are unregistered, free the spare array */
4394 kfree(thresholds
->spare
);
4395 thresholds
->spare
= NULL
;
4398 mutex_unlock(&memcg
->thresholds_lock
);
4401 static void mem_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4402 struct eventfd_ctx
*eventfd
)
4404 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEM
);
4407 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup
*memcg
,
4408 struct eventfd_ctx
*eventfd
)
4410 return __mem_cgroup_usage_unregister_event(memcg
, eventfd
, _MEMSWAP
);
4413 static int mem_cgroup_oom_register_event(struct mem_cgroup
*memcg
,
4414 struct eventfd_ctx
*eventfd
, const char *args
)
4416 struct mem_cgroup_eventfd_list
*event
;
4418 event
= kmalloc(sizeof(*event
), GFP_KERNEL
);
4422 spin_lock(&memcg_oom_lock
);
4424 event
->eventfd
= eventfd
;
4425 list_add(&event
->list
, &memcg
->oom_notify
);
4427 /* already in OOM ? */
4428 if (memcg
->under_oom
)
4429 eventfd_signal(eventfd
, 1);
4430 spin_unlock(&memcg_oom_lock
);
4435 static void mem_cgroup_oom_unregister_event(struct mem_cgroup
*memcg
,
4436 struct eventfd_ctx
*eventfd
)
4438 struct mem_cgroup_eventfd_list
*ev
, *tmp
;
4440 spin_lock(&memcg_oom_lock
);
4442 list_for_each_entry_safe(ev
, tmp
, &memcg
->oom_notify
, list
) {
4443 if (ev
->eventfd
== eventfd
) {
4444 list_del(&ev
->list
);
4449 spin_unlock(&memcg_oom_lock
);
4452 static int mem_cgroup_oom_control_read(struct seq_file
*sf
, void *v
)
4454 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(sf
);
4456 seq_printf(sf
, "oom_kill_disable %d\n", memcg
->oom_kill_disable
);
4457 seq_printf(sf
, "under_oom %d\n", (bool)memcg
->under_oom
);
4458 seq_printf(sf
, "oom_kill %lu\n",
4459 atomic_long_read(&memcg
->memory_events
[MEMCG_OOM_KILL
]));
4463 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state
*css
,
4464 struct cftype
*cft
, u64 val
)
4466 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4468 /* cannot set to root cgroup and only 0 and 1 are allowed */
4469 if (mem_cgroup_is_root(memcg
) || !((val
== 0) || (val
== 1)))
4472 memcg
->oom_kill_disable
= val
;
4474 memcg_oom_recover(memcg
);
4479 #ifdef CONFIG_CGROUP_WRITEBACK
4481 #include <trace/events/writeback.h>
4483 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4485 return wb_domain_init(&memcg
->cgwb_domain
, gfp
);
4488 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4490 wb_domain_exit(&memcg
->cgwb_domain
);
4493 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4495 wb_domain_size_changed(&memcg
->cgwb_domain
);
4498 struct wb_domain
*mem_cgroup_wb_domain(struct bdi_writeback
*wb
)
4500 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4502 if (!memcg
->css
.parent
)
4505 return &memcg
->cgwb_domain
;
4509 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4510 * @wb: bdi_writeback in question
4511 * @pfilepages: out parameter for number of file pages
4512 * @pheadroom: out parameter for number of allocatable pages according to memcg
4513 * @pdirty: out parameter for number of dirty pages
4514 * @pwriteback: out parameter for number of pages under writeback
4516 * Determine the numbers of file, headroom, dirty, and writeback pages in
4517 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4518 * is a bit more involved.
4520 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4521 * headroom is calculated as the lowest headroom of itself and the
4522 * ancestors. Note that this doesn't consider the actual amount of
4523 * available memory in the system. The caller should further cap
4524 * *@pheadroom accordingly.
4526 void mem_cgroup_wb_stats(struct bdi_writeback
*wb
, unsigned long *pfilepages
,
4527 unsigned long *pheadroom
, unsigned long *pdirty
,
4528 unsigned long *pwriteback
)
4530 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4531 struct mem_cgroup
*parent
;
4533 cgroup_rstat_flush_irqsafe(memcg
->css
.cgroup
);
4535 *pdirty
= memcg_page_state(memcg
, NR_FILE_DIRTY
);
4536 *pwriteback
= memcg_page_state(memcg
, NR_WRITEBACK
);
4537 *pfilepages
= memcg_page_state(memcg
, NR_INACTIVE_FILE
) +
4538 memcg_page_state(memcg
, NR_ACTIVE_FILE
);
4540 *pheadroom
= PAGE_COUNTER_MAX
;
4541 while ((parent
= parent_mem_cgroup(memcg
))) {
4542 unsigned long ceiling
= min(READ_ONCE(memcg
->memory
.max
),
4543 READ_ONCE(memcg
->memory
.high
));
4544 unsigned long used
= page_counter_read(&memcg
->memory
);
4546 *pheadroom
= min(*pheadroom
, ceiling
- min(ceiling
, used
));
4552 * Foreign dirty flushing
4554 * There's an inherent mismatch between memcg and writeback. The former
4555 * tracks ownership per-page while the latter per-inode. This was a
4556 * deliberate design decision because honoring per-page ownership in the
4557 * writeback path is complicated, may lead to higher CPU and IO overheads
4558 * and deemed unnecessary given that write-sharing an inode across
4559 * different cgroups isn't a common use-case.
4561 * Combined with inode majority-writer ownership switching, this works well
4562 * enough in most cases but there are some pathological cases. For
4563 * example, let's say there are two cgroups A and B which keep writing to
4564 * different but confined parts of the same inode. B owns the inode and
4565 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4566 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4567 * triggering background writeback. A will be slowed down without a way to
4568 * make writeback of the dirty pages happen.
4570 * Conditions like the above can lead to a cgroup getting repeatedly and
4571 * severely throttled after making some progress after each
4572 * dirty_expire_interval while the underlying IO device is almost
4575 * Solving this problem completely requires matching the ownership tracking
4576 * granularities between memcg and writeback in either direction. However,
4577 * the more egregious behaviors can be avoided by simply remembering the
4578 * most recent foreign dirtying events and initiating remote flushes on
4579 * them when local writeback isn't enough to keep the memory clean enough.
4581 * The following two functions implement such mechanism. When a foreign
4582 * page - a page whose memcg and writeback ownerships don't match - is
4583 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4584 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4585 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4586 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4587 * foreign bdi_writebacks which haven't expired. Both the numbers of
4588 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4589 * limited to MEMCG_CGWB_FRN_CNT.
4591 * The mechanism only remembers IDs and doesn't hold any object references.
4592 * As being wrong occasionally doesn't matter, updates and accesses to the
4593 * records are lockless and racy.
4595 void mem_cgroup_track_foreign_dirty_slowpath(struct page
*page
,
4596 struct bdi_writeback
*wb
)
4598 struct mem_cgroup
*memcg
= page_memcg(page
);
4599 struct memcg_cgwb_frn
*frn
;
4600 u64 now
= get_jiffies_64();
4601 u64 oldest_at
= now
;
4605 trace_track_foreign_dirty(page
, wb
);
4608 * Pick the slot to use. If there is already a slot for @wb, keep
4609 * using it. If not replace the oldest one which isn't being
4612 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4613 frn
= &memcg
->cgwb_frn
[i
];
4614 if (frn
->bdi_id
== wb
->bdi
->id
&&
4615 frn
->memcg_id
== wb
->memcg_css
->id
)
4617 if (time_before64(frn
->at
, oldest_at
) &&
4618 atomic_read(&frn
->done
.cnt
) == 1) {
4620 oldest_at
= frn
->at
;
4624 if (i
< MEMCG_CGWB_FRN_CNT
) {
4626 * Re-using an existing one. Update timestamp lazily to
4627 * avoid making the cacheline hot. We want them to be
4628 * reasonably up-to-date and significantly shorter than
4629 * dirty_expire_interval as that's what expires the record.
4630 * Use the shorter of 1s and dirty_expire_interval / 8.
4632 unsigned long update_intv
=
4633 min_t(unsigned long, HZ
,
4634 msecs_to_jiffies(dirty_expire_interval
* 10) / 8);
4636 if (time_before64(frn
->at
, now
- update_intv
))
4638 } else if (oldest
>= 0) {
4639 /* replace the oldest free one */
4640 frn
= &memcg
->cgwb_frn
[oldest
];
4641 frn
->bdi_id
= wb
->bdi
->id
;
4642 frn
->memcg_id
= wb
->memcg_css
->id
;
4647 /* issue foreign writeback flushes for recorded foreign dirtying events */
4648 void mem_cgroup_flush_foreign(struct bdi_writeback
*wb
)
4650 struct mem_cgroup
*memcg
= mem_cgroup_from_css(wb
->memcg_css
);
4651 unsigned long intv
= msecs_to_jiffies(dirty_expire_interval
* 10);
4652 u64 now
= jiffies_64
;
4655 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++) {
4656 struct memcg_cgwb_frn
*frn
= &memcg
->cgwb_frn
[i
];
4659 * If the record is older than dirty_expire_interval,
4660 * writeback on it has already started. No need to kick it
4661 * off again. Also, don't start a new one if there's
4662 * already one in flight.
4664 if (time_after64(frn
->at
, now
- intv
) &&
4665 atomic_read(&frn
->done
.cnt
) == 1) {
4667 trace_flush_foreign(wb
, frn
->bdi_id
, frn
->memcg_id
);
4668 cgroup_writeback_by_id(frn
->bdi_id
, frn
->memcg_id
, 0,
4669 WB_REASON_FOREIGN_FLUSH
,
4675 #else /* CONFIG_CGROUP_WRITEBACK */
4677 static int memcg_wb_domain_init(struct mem_cgroup
*memcg
, gfp_t gfp
)
4682 static void memcg_wb_domain_exit(struct mem_cgroup
*memcg
)
4686 static void memcg_wb_domain_size_changed(struct mem_cgroup
*memcg
)
4690 #endif /* CONFIG_CGROUP_WRITEBACK */
4693 * DO NOT USE IN NEW FILES.
4695 * "cgroup.event_control" implementation.
4697 * This is way over-engineered. It tries to support fully configurable
4698 * events for each user. Such level of flexibility is completely
4699 * unnecessary especially in the light of the planned unified hierarchy.
4701 * Please deprecate this and replace with something simpler if at all
4706 * Unregister event and free resources.
4708 * Gets called from workqueue.
4710 static void memcg_event_remove(struct work_struct
*work
)
4712 struct mem_cgroup_event
*event
=
4713 container_of(work
, struct mem_cgroup_event
, remove
);
4714 struct mem_cgroup
*memcg
= event
->memcg
;
4716 remove_wait_queue(event
->wqh
, &event
->wait
);
4718 event
->unregister_event(memcg
, event
->eventfd
);
4720 /* Notify userspace the event is going away. */
4721 eventfd_signal(event
->eventfd
, 1);
4723 eventfd_ctx_put(event
->eventfd
);
4725 css_put(&memcg
->css
);
4729 * Gets called on EPOLLHUP on eventfd when user closes it.
4731 * Called with wqh->lock held and interrupts disabled.
4733 static int memcg_event_wake(wait_queue_entry_t
*wait
, unsigned mode
,
4734 int sync
, void *key
)
4736 struct mem_cgroup_event
*event
=
4737 container_of(wait
, struct mem_cgroup_event
, wait
);
4738 struct mem_cgroup
*memcg
= event
->memcg
;
4739 __poll_t flags
= key_to_poll(key
);
4741 if (flags
& EPOLLHUP
) {
4743 * If the event has been detached at cgroup removal, we
4744 * can simply return knowing the other side will cleanup
4747 * We can't race against event freeing since the other
4748 * side will require wqh->lock via remove_wait_queue(),
4751 spin_lock(&memcg
->event_list_lock
);
4752 if (!list_empty(&event
->list
)) {
4753 list_del_init(&event
->list
);
4755 * We are in atomic context, but cgroup_event_remove()
4756 * may sleep, so we have to call it in workqueue.
4758 schedule_work(&event
->remove
);
4760 spin_unlock(&memcg
->event_list_lock
);
4766 static void memcg_event_ptable_queue_proc(struct file
*file
,
4767 wait_queue_head_t
*wqh
, poll_table
*pt
)
4769 struct mem_cgroup_event
*event
=
4770 container_of(pt
, struct mem_cgroup_event
, pt
);
4773 add_wait_queue(wqh
, &event
->wait
);
4777 * DO NOT USE IN NEW FILES.
4779 * Parse input and register new cgroup event handler.
4781 * Input must be in format '<event_fd> <control_fd> <args>'.
4782 * Interpretation of args is defined by control file implementation.
4784 static ssize_t
memcg_write_event_control(struct kernfs_open_file
*of
,
4785 char *buf
, size_t nbytes
, loff_t off
)
4787 struct cgroup_subsys_state
*css
= of_css(of
);
4788 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
4789 struct mem_cgroup_event
*event
;
4790 struct cgroup_subsys_state
*cfile_css
;
4791 unsigned int efd
, cfd
;
4798 buf
= strstrip(buf
);
4800 efd
= simple_strtoul(buf
, &endp
, 10);
4805 cfd
= simple_strtoul(buf
, &endp
, 10);
4806 if ((*endp
!= ' ') && (*endp
!= '\0'))
4810 event
= kzalloc(sizeof(*event
), GFP_KERNEL
);
4814 event
->memcg
= memcg
;
4815 INIT_LIST_HEAD(&event
->list
);
4816 init_poll_funcptr(&event
->pt
, memcg_event_ptable_queue_proc
);
4817 init_waitqueue_func_entry(&event
->wait
, memcg_event_wake
);
4818 INIT_WORK(&event
->remove
, memcg_event_remove
);
4826 event
->eventfd
= eventfd_ctx_fileget(efile
.file
);
4827 if (IS_ERR(event
->eventfd
)) {
4828 ret
= PTR_ERR(event
->eventfd
);
4835 goto out_put_eventfd
;
4838 /* the process need read permission on control file */
4839 /* AV: shouldn't we check that it's been opened for read instead? */
4840 ret
= file_permission(cfile
.file
, MAY_READ
);
4845 * Determine the event callbacks and set them in @event. This used
4846 * to be done via struct cftype but cgroup core no longer knows
4847 * about these events. The following is crude but the whole thing
4848 * is for compatibility anyway.
4850 * DO NOT ADD NEW FILES.
4852 name
= cfile
.file
->f_path
.dentry
->d_name
.name
;
4854 if (!strcmp(name
, "memory.usage_in_bytes")) {
4855 event
->register_event
= mem_cgroup_usage_register_event
;
4856 event
->unregister_event
= mem_cgroup_usage_unregister_event
;
4857 } else if (!strcmp(name
, "memory.oom_control")) {
4858 event
->register_event
= mem_cgroup_oom_register_event
;
4859 event
->unregister_event
= mem_cgroup_oom_unregister_event
;
4860 } else if (!strcmp(name
, "memory.pressure_level")) {
4861 event
->register_event
= vmpressure_register_event
;
4862 event
->unregister_event
= vmpressure_unregister_event
;
4863 } else if (!strcmp(name
, "memory.memsw.usage_in_bytes")) {
4864 event
->register_event
= memsw_cgroup_usage_register_event
;
4865 event
->unregister_event
= memsw_cgroup_usage_unregister_event
;
4872 * Verify @cfile should belong to @css. Also, remaining events are
4873 * automatically removed on cgroup destruction but the removal is
4874 * asynchronous, so take an extra ref on @css.
4876 cfile_css
= css_tryget_online_from_dir(cfile
.file
->f_path
.dentry
->d_parent
,
4877 &memory_cgrp_subsys
);
4879 if (IS_ERR(cfile_css
))
4881 if (cfile_css
!= css
) {
4886 ret
= event
->register_event(memcg
, event
->eventfd
, buf
);
4890 vfs_poll(efile
.file
, &event
->pt
);
4892 spin_lock(&memcg
->event_list_lock
);
4893 list_add(&event
->list
, &memcg
->event_list
);
4894 spin_unlock(&memcg
->event_list_lock
);
4906 eventfd_ctx_put(event
->eventfd
);
4915 static struct cftype mem_cgroup_legacy_files
[] = {
4917 .name
= "usage_in_bytes",
4918 .private = MEMFILE_PRIVATE(_MEM
, RES_USAGE
),
4919 .read_u64
= mem_cgroup_read_u64
,
4922 .name
= "max_usage_in_bytes",
4923 .private = MEMFILE_PRIVATE(_MEM
, RES_MAX_USAGE
),
4924 .write
= mem_cgroup_reset
,
4925 .read_u64
= mem_cgroup_read_u64
,
4928 .name
= "limit_in_bytes",
4929 .private = MEMFILE_PRIVATE(_MEM
, RES_LIMIT
),
4930 .write
= mem_cgroup_write
,
4931 .read_u64
= mem_cgroup_read_u64
,
4934 .name
= "soft_limit_in_bytes",
4935 .private = MEMFILE_PRIVATE(_MEM
, RES_SOFT_LIMIT
),
4936 .write
= mem_cgroup_write
,
4937 .read_u64
= mem_cgroup_read_u64
,
4941 .private = MEMFILE_PRIVATE(_MEM
, RES_FAILCNT
),
4942 .write
= mem_cgroup_reset
,
4943 .read_u64
= mem_cgroup_read_u64
,
4947 .seq_show
= memcg_stat_show
,
4950 .name
= "force_empty",
4951 .write
= mem_cgroup_force_empty_write
,
4954 .name
= "use_hierarchy",
4955 .write_u64
= mem_cgroup_hierarchy_write
,
4956 .read_u64
= mem_cgroup_hierarchy_read
,
4959 .name
= "cgroup.event_control", /* XXX: for compat */
4960 .write
= memcg_write_event_control
,
4961 .flags
= CFTYPE_NO_PREFIX
| CFTYPE_WORLD_WRITABLE
,
4964 .name
= "swappiness",
4965 .read_u64
= mem_cgroup_swappiness_read
,
4966 .write_u64
= mem_cgroup_swappiness_write
,
4969 .name
= "move_charge_at_immigrate",
4970 .read_u64
= mem_cgroup_move_charge_read
,
4971 .write_u64
= mem_cgroup_move_charge_write
,
4974 .name
= "oom_control",
4975 .seq_show
= mem_cgroup_oom_control_read
,
4976 .write_u64
= mem_cgroup_oom_control_write
,
4977 .private = MEMFILE_PRIVATE(_OOM_TYPE
, OOM_CONTROL
),
4980 .name
= "pressure_level",
4984 .name
= "numa_stat",
4985 .seq_show
= memcg_numa_stat_show
,
4989 .name
= "kmem.limit_in_bytes",
4990 .private = MEMFILE_PRIVATE(_KMEM
, RES_LIMIT
),
4991 .write
= mem_cgroup_write
,
4992 .read_u64
= mem_cgroup_read_u64
,
4995 .name
= "kmem.usage_in_bytes",
4996 .private = MEMFILE_PRIVATE(_KMEM
, RES_USAGE
),
4997 .read_u64
= mem_cgroup_read_u64
,
5000 .name
= "kmem.failcnt",
5001 .private = MEMFILE_PRIVATE(_KMEM
, RES_FAILCNT
),
5002 .write
= mem_cgroup_reset
,
5003 .read_u64
= mem_cgroup_read_u64
,
5006 .name
= "kmem.max_usage_in_bytes",
5007 .private = MEMFILE_PRIVATE(_KMEM
, RES_MAX_USAGE
),
5008 .write
= mem_cgroup_reset
,
5009 .read_u64
= mem_cgroup_read_u64
,
5011 #if defined(CONFIG_MEMCG_KMEM) && \
5012 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
5014 .name
= "kmem.slabinfo",
5015 .seq_show
= memcg_slab_show
,
5019 .name
= "kmem.tcp.limit_in_bytes",
5020 .private = MEMFILE_PRIVATE(_TCP
, RES_LIMIT
),
5021 .write
= mem_cgroup_write
,
5022 .read_u64
= mem_cgroup_read_u64
,
5025 .name
= "kmem.tcp.usage_in_bytes",
5026 .private = MEMFILE_PRIVATE(_TCP
, RES_USAGE
),
5027 .read_u64
= mem_cgroup_read_u64
,
5030 .name
= "kmem.tcp.failcnt",
5031 .private = MEMFILE_PRIVATE(_TCP
, RES_FAILCNT
),
5032 .write
= mem_cgroup_reset
,
5033 .read_u64
= mem_cgroup_read_u64
,
5036 .name
= "kmem.tcp.max_usage_in_bytes",
5037 .private = MEMFILE_PRIVATE(_TCP
, RES_MAX_USAGE
),
5038 .write
= mem_cgroup_reset
,
5039 .read_u64
= mem_cgroup_read_u64
,
5041 { }, /* terminate */
5045 * Private memory cgroup IDR
5047 * Swap-out records and page cache shadow entries need to store memcg
5048 * references in constrained space, so we maintain an ID space that is
5049 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
5050 * memory-controlled cgroups to 64k.
5052 * However, there usually are many references to the offline CSS after
5053 * the cgroup has been destroyed, such as page cache or reclaimable
5054 * slab objects, that don't need to hang on to the ID. We want to keep
5055 * those dead CSS from occupying IDs, or we might quickly exhaust the
5056 * relatively small ID space and prevent the creation of new cgroups
5057 * even when there are much fewer than 64k cgroups - possibly none.
5059 * Maintain a private 16-bit ID space for memcg, and allow the ID to
5060 * be freed and recycled when it's no longer needed, which is usually
5061 * when the CSS is offlined.
5063 * The only exception to that are records of swapped out tmpfs/shmem
5064 * pages that need to be attributed to live ancestors on swapin. But
5065 * those references are manageable from userspace.
5068 static DEFINE_IDR(mem_cgroup_idr
);
5070 static void mem_cgroup_id_remove(struct mem_cgroup
*memcg
)
5072 if (memcg
->id
.id
> 0) {
5073 idr_remove(&mem_cgroup_idr
, memcg
->id
.id
);
5078 static void __maybe_unused
mem_cgroup_id_get_many(struct mem_cgroup
*memcg
,
5081 refcount_add(n
, &memcg
->id
.ref
);
5084 static void mem_cgroup_id_put_many(struct mem_cgroup
*memcg
, unsigned int n
)
5086 if (refcount_sub_and_test(n
, &memcg
->id
.ref
)) {
5087 mem_cgroup_id_remove(memcg
);
5089 /* Memcg ID pins CSS */
5090 css_put(&memcg
->css
);
5094 static inline void mem_cgroup_id_put(struct mem_cgroup
*memcg
)
5096 mem_cgroup_id_put_many(memcg
, 1);
5100 * mem_cgroup_from_id - look up a memcg from a memcg id
5101 * @id: the memcg id to look up
5103 * Caller must hold rcu_read_lock().
5105 struct mem_cgroup
*mem_cgroup_from_id(unsigned short id
)
5107 WARN_ON_ONCE(!rcu_read_lock_held());
5108 return idr_find(&mem_cgroup_idr
, id
);
5111 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
5113 struct mem_cgroup_per_node
*pn
;
5116 * This routine is called against possible nodes.
5117 * But it's BUG to call kmalloc() against offline node.
5119 * TODO: this routine can waste much memory for nodes which will
5120 * never be onlined. It's better to use memory hotplug callback
5123 if (!node_state(node
, N_NORMAL_MEMORY
))
5125 pn
= kzalloc_node(sizeof(*pn
), GFP_KERNEL
, tmp
);
5129 pn
->lruvec_stat_local
= alloc_percpu_gfp(struct lruvec_stat
,
5130 GFP_KERNEL_ACCOUNT
);
5131 if (!pn
->lruvec_stat_local
) {
5136 pn
->lruvec_stat_cpu
= alloc_percpu_gfp(struct batched_lruvec_stat
,
5137 GFP_KERNEL_ACCOUNT
);
5138 if (!pn
->lruvec_stat_cpu
) {
5139 free_percpu(pn
->lruvec_stat_local
);
5144 lruvec_init(&pn
->lruvec
);
5145 pn
->usage_in_excess
= 0;
5146 pn
->on_tree
= false;
5149 memcg
->nodeinfo
[node
] = pn
;
5153 static void free_mem_cgroup_per_node_info(struct mem_cgroup
*memcg
, int node
)
5155 struct mem_cgroup_per_node
*pn
= memcg
->nodeinfo
[node
];
5160 free_percpu(pn
->lruvec_stat_cpu
);
5161 free_percpu(pn
->lruvec_stat_local
);
5165 static void __mem_cgroup_free(struct mem_cgroup
*memcg
)
5170 free_mem_cgroup_per_node_info(memcg
, node
);
5171 free_percpu(memcg
->vmstats_percpu
);
5175 static void mem_cgroup_free(struct mem_cgroup
*memcg
)
5179 memcg_wb_domain_exit(memcg
);
5181 * Flush percpu lruvec stats to guarantee the value
5182 * correctness on parent's and all ancestor levels.
5184 for_each_online_cpu(cpu
)
5185 memcg_flush_lruvec_page_state(memcg
, cpu
);
5186 __mem_cgroup_free(memcg
);
5189 static struct mem_cgroup
*mem_cgroup_alloc(void)
5191 struct mem_cgroup
*memcg
;
5194 int __maybe_unused i
;
5195 long error
= -ENOMEM
;
5197 size
= sizeof(struct mem_cgroup
);
5198 size
+= nr_node_ids
* sizeof(struct mem_cgroup_per_node
*);
5200 memcg
= kzalloc(size
, GFP_KERNEL
);
5202 return ERR_PTR(error
);
5204 memcg
->id
.id
= idr_alloc(&mem_cgroup_idr
, NULL
,
5205 1, MEM_CGROUP_ID_MAX
,
5207 if (memcg
->id
.id
< 0) {
5208 error
= memcg
->id
.id
;
5212 memcg
->vmstats_percpu
= alloc_percpu_gfp(struct memcg_vmstats_percpu
,
5213 GFP_KERNEL_ACCOUNT
);
5214 if (!memcg
->vmstats_percpu
)
5218 if (alloc_mem_cgroup_per_node_info(memcg
, node
))
5221 if (memcg_wb_domain_init(memcg
, GFP_KERNEL
))
5224 INIT_WORK(&memcg
->high_work
, high_work_func
);
5225 INIT_LIST_HEAD(&memcg
->oom_notify
);
5226 mutex_init(&memcg
->thresholds_lock
);
5227 spin_lock_init(&memcg
->move_lock
);
5228 vmpressure_init(&memcg
->vmpressure
);
5229 INIT_LIST_HEAD(&memcg
->event_list
);
5230 spin_lock_init(&memcg
->event_list_lock
);
5231 memcg
->socket_pressure
= jiffies
;
5232 #ifdef CONFIG_MEMCG_KMEM
5233 memcg
->kmemcg_id
= -1;
5234 INIT_LIST_HEAD(&memcg
->objcg_list
);
5236 #ifdef CONFIG_CGROUP_WRITEBACK
5237 INIT_LIST_HEAD(&memcg
->cgwb_list
);
5238 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5239 memcg
->cgwb_frn
[i
].done
=
5240 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq
);
5242 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5243 spin_lock_init(&memcg
->deferred_split_queue
.split_queue_lock
);
5244 INIT_LIST_HEAD(&memcg
->deferred_split_queue
.split_queue
);
5245 memcg
->deferred_split_queue
.split_queue_len
= 0;
5247 idr_replace(&mem_cgroup_idr
, memcg
, memcg
->id
.id
);
5250 mem_cgroup_id_remove(memcg
);
5251 __mem_cgroup_free(memcg
);
5252 return ERR_PTR(error
);
5255 static struct cgroup_subsys_state
* __ref
5256 mem_cgroup_css_alloc(struct cgroup_subsys_state
*parent_css
)
5258 struct mem_cgroup
*parent
= mem_cgroup_from_css(parent_css
);
5259 struct mem_cgroup
*memcg
, *old_memcg
;
5260 long error
= -ENOMEM
;
5262 old_memcg
= set_active_memcg(parent
);
5263 memcg
= mem_cgroup_alloc();
5264 set_active_memcg(old_memcg
);
5266 return ERR_CAST(memcg
);
5268 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5269 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5270 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5272 memcg
->swappiness
= mem_cgroup_swappiness(parent
);
5273 memcg
->oom_kill_disable
= parent
->oom_kill_disable
;
5275 page_counter_init(&memcg
->memory
, &parent
->memory
);
5276 page_counter_init(&memcg
->swap
, &parent
->swap
);
5277 page_counter_init(&memcg
->kmem
, &parent
->kmem
);
5278 page_counter_init(&memcg
->tcpmem
, &parent
->tcpmem
);
5280 page_counter_init(&memcg
->memory
, NULL
);
5281 page_counter_init(&memcg
->swap
, NULL
);
5282 page_counter_init(&memcg
->kmem
, NULL
);
5283 page_counter_init(&memcg
->tcpmem
, NULL
);
5285 root_mem_cgroup
= memcg
;
5289 /* The following stuff does not apply to the root */
5290 error
= memcg_online_kmem(memcg
);
5294 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5295 static_branch_inc(&memcg_sockets_enabled_key
);
5299 mem_cgroup_id_remove(memcg
);
5300 mem_cgroup_free(memcg
);
5301 return ERR_PTR(error
);
5304 static int mem_cgroup_css_online(struct cgroup_subsys_state
*css
)
5306 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5309 * A memcg must be visible for expand_shrinker_info()
5310 * by the time the maps are allocated. So, we allocate maps
5311 * here, when for_each_mem_cgroup() can't skip it.
5313 if (alloc_shrinker_info(memcg
)) {
5314 mem_cgroup_id_remove(memcg
);
5318 /* Online state pins memcg ID, memcg ID pins CSS */
5319 refcount_set(&memcg
->id
.ref
, 1);
5324 static void mem_cgroup_css_offline(struct cgroup_subsys_state
*css
)
5326 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5327 struct mem_cgroup_event
*event
, *tmp
;
5330 * Unregister events and notify userspace.
5331 * Notify userspace about cgroup removing only after rmdir of cgroup
5332 * directory to avoid race between userspace and kernelspace.
5334 spin_lock(&memcg
->event_list_lock
);
5335 list_for_each_entry_safe(event
, tmp
, &memcg
->event_list
, list
) {
5336 list_del_init(&event
->list
);
5337 schedule_work(&event
->remove
);
5339 spin_unlock(&memcg
->event_list_lock
);
5341 page_counter_set_min(&memcg
->memory
, 0);
5342 page_counter_set_low(&memcg
->memory
, 0);
5344 memcg_offline_kmem(memcg
);
5345 reparent_shrinker_deferred(memcg
);
5346 wb_memcg_offline(memcg
);
5348 drain_all_stock(memcg
);
5350 mem_cgroup_id_put(memcg
);
5353 static void mem_cgroup_css_released(struct cgroup_subsys_state
*css
)
5355 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5357 invalidate_reclaim_iterators(memcg
);
5360 static void mem_cgroup_css_free(struct cgroup_subsys_state
*css
)
5362 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5363 int __maybe_unused i
;
5365 #ifdef CONFIG_CGROUP_WRITEBACK
5366 for (i
= 0; i
< MEMCG_CGWB_FRN_CNT
; i
++)
5367 wb_wait_for_completion(&memcg
->cgwb_frn
[i
].done
);
5369 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !cgroup_memory_nosocket
)
5370 static_branch_dec(&memcg_sockets_enabled_key
);
5372 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && memcg
->tcpmem_active
)
5373 static_branch_dec(&memcg_sockets_enabled_key
);
5375 vmpressure_cleanup(&memcg
->vmpressure
);
5376 cancel_work_sync(&memcg
->high_work
);
5377 mem_cgroup_remove_from_trees(memcg
);
5378 free_shrinker_info(memcg
);
5379 memcg_free_kmem(memcg
);
5380 mem_cgroup_free(memcg
);
5384 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5385 * @css: the target css
5387 * Reset the states of the mem_cgroup associated with @css. This is
5388 * invoked when the userland requests disabling on the default hierarchy
5389 * but the memcg is pinned through dependency. The memcg should stop
5390 * applying policies and should revert to the vanilla state as it may be
5391 * made visible again.
5393 * The current implementation only resets the essential configurations.
5394 * This needs to be expanded to cover all the visible parts.
5396 static void mem_cgroup_css_reset(struct cgroup_subsys_state
*css
)
5398 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5400 page_counter_set_max(&memcg
->memory
, PAGE_COUNTER_MAX
);
5401 page_counter_set_max(&memcg
->swap
, PAGE_COUNTER_MAX
);
5402 page_counter_set_max(&memcg
->kmem
, PAGE_COUNTER_MAX
);
5403 page_counter_set_max(&memcg
->tcpmem
, PAGE_COUNTER_MAX
);
5404 page_counter_set_min(&memcg
->memory
, 0);
5405 page_counter_set_low(&memcg
->memory
, 0);
5406 page_counter_set_high(&memcg
->memory
, PAGE_COUNTER_MAX
);
5407 memcg
->soft_limit
= PAGE_COUNTER_MAX
;
5408 page_counter_set_high(&memcg
->swap
, PAGE_COUNTER_MAX
);
5409 memcg_wb_domain_size_changed(memcg
);
5412 static void mem_cgroup_css_rstat_flush(struct cgroup_subsys_state
*css
, int cpu
)
5414 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
5415 struct mem_cgroup
*parent
= parent_mem_cgroup(memcg
);
5416 struct memcg_vmstats_percpu
*statc
;
5420 statc
= per_cpu_ptr(memcg
->vmstats_percpu
, cpu
);
5422 for (i
= 0; i
< MEMCG_NR_STAT
; i
++) {
5424 * Collect the aggregated propagation counts of groups
5425 * below us. We're in a per-cpu loop here and this is
5426 * a global counter, so the first cycle will get them.
5428 delta
= memcg
->vmstats
.state_pending
[i
];
5430 memcg
->vmstats
.state_pending
[i
] = 0;
5432 /* Add CPU changes on this level since the last flush */
5433 v
= READ_ONCE(statc
->state
[i
]);
5434 if (v
!= statc
->state_prev
[i
]) {
5435 delta
+= v
- statc
->state_prev
[i
];
5436 statc
->state_prev
[i
] = v
;
5442 /* Aggregate counts on this level and propagate upwards */
5443 memcg
->vmstats
.state
[i
] += delta
;
5445 parent
->vmstats
.state_pending
[i
] += delta
;
5448 for (i
= 0; i
< NR_VM_EVENT_ITEMS
; i
++) {
5449 delta
= memcg
->vmstats
.events_pending
[i
];
5451 memcg
->vmstats
.events_pending
[i
] = 0;
5453 v
= READ_ONCE(statc
->events
[i
]);
5454 if (v
!= statc
->events_prev
[i
]) {
5455 delta
+= v
- statc
->events_prev
[i
];
5456 statc
->events_prev
[i
] = v
;
5462 memcg
->vmstats
.events
[i
] += delta
;
5464 parent
->vmstats
.events_pending
[i
] += delta
;
5469 /* Handlers for move charge at task migration. */
5470 static int mem_cgroup_do_precharge(unsigned long count
)
5474 /* Try a single bulk charge without reclaim first, kswapd may wake */
5475 ret
= try_charge(mc
.to
, GFP_KERNEL
& ~__GFP_DIRECT_RECLAIM
, count
);
5477 mc
.precharge
+= count
;
5481 /* Try charges one by one with reclaim, but do not retry */
5483 ret
= try_charge(mc
.to
, GFP_KERNEL
| __GFP_NORETRY
, 1);
5497 enum mc_target_type
{
5504 static struct page
*mc_handle_present_pte(struct vm_area_struct
*vma
,
5505 unsigned long addr
, pte_t ptent
)
5507 struct page
*page
= vm_normal_page(vma
, addr
, ptent
);
5509 if (!page
|| !page_mapped(page
))
5511 if (PageAnon(page
)) {
5512 if (!(mc
.flags
& MOVE_ANON
))
5515 if (!(mc
.flags
& MOVE_FILE
))
5518 if (!get_page_unless_zero(page
))
5524 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5525 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5526 pte_t ptent
, swp_entry_t
*entry
)
5528 struct page
*page
= NULL
;
5529 swp_entry_t ent
= pte_to_swp_entry(ptent
);
5531 if (!(mc
.flags
& MOVE_ANON
))
5535 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5536 * a device and because they are not accessible by CPU they are store
5537 * as special swap entry in the CPU page table.
5539 if (is_device_private_entry(ent
)) {
5540 page
= pfn_swap_entry_to_page(ent
);
5542 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5543 * a refcount of 1 when free (unlike normal page)
5545 if (!page_ref_add_unless(page
, 1, 1))
5550 if (non_swap_entry(ent
))
5554 * Because lookup_swap_cache() updates some statistics counter,
5555 * we call find_get_page() with swapper_space directly.
5557 page
= find_get_page(swap_address_space(ent
), swp_offset(ent
));
5558 entry
->val
= ent
.val
;
5563 static struct page
*mc_handle_swap_pte(struct vm_area_struct
*vma
,
5564 pte_t ptent
, swp_entry_t
*entry
)
5570 static struct page
*mc_handle_file_pte(struct vm_area_struct
*vma
,
5571 unsigned long addr
, pte_t ptent
, swp_entry_t
*entry
)
5573 if (!vma
->vm_file
) /* anonymous vma */
5575 if (!(mc
.flags
& MOVE_FILE
))
5578 /* page is moved even if it's not RSS of this task(page-faulted). */
5579 /* shmem/tmpfs may report page out on swap: account for that too. */
5580 return find_get_incore_page(vma
->vm_file
->f_mapping
,
5581 linear_page_index(vma
, addr
));
5585 * mem_cgroup_move_account - move account of the page
5587 * @compound: charge the page as compound or small page
5588 * @from: mem_cgroup which the page is moved from.
5589 * @to: mem_cgroup which the page is moved to. @from != @to.
5591 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5593 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5596 static int mem_cgroup_move_account(struct page
*page
,
5598 struct mem_cgroup
*from
,
5599 struct mem_cgroup
*to
)
5601 struct lruvec
*from_vec
, *to_vec
;
5602 struct pglist_data
*pgdat
;
5603 unsigned int nr_pages
= compound
? thp_nr_pages(page
) : 1;
5606 VM_BUG_ON(from
== to
);
5607 VM_BUG_ON_PAGE(PageLRU(page
), page
);
5608 VM_BUG_ON(compound
&& !PageTransHuge(page
));
5611 * Prevent mem_cgroup_migrate() from looking at
5612 * page's memory cgroup of its source page while we change it.
5615 if (!trylock_page(page
))
5619 if (page_memcg(page
) != from
)
5622 pgdat
= page_pgdat(page
);
5623 from_vec
= mem_cgroup_lruvec(from
, pgdat
);
5624 to_vec
= mem_cgroup_lruvec(to
, pgdat
);
5626 lock_page_memcg(page
);
5628 if (PageAnon(page
)) {
5629 if (page_mapped(page
)) {
5630 __mod_lruvec_state(from_vec
, NR_ANON_MAPPED
, -nr_pages
);
5631 __mod_lruvec_state(to_vec
, NR_ANON_MAPPED
, nr_pages
);
5632 if (PageTransHuge(page
)) {
5633 __mod_lruvec_state(from_vec
, NR_ANON_THPS
,
5635 __mod_lruvec_state(to_vec
, NR_ANON_THPS
,
5640 __mod_lruvec_state(from_vec
, NR_FILE_PAGES
, -nr_pages
);
5641 __mod_lruvec_state(to_vec
, NR_FILE_PAGES
, nr_pages
);
5643 if (PageSwapBacked(page
)) {
5644 __mod_lruvec_state(from_vec
, NR_SHMEM
, -nr_pages
);
5645 __mod_lruvec_state(to_vec
, NR_SHMEM
, nr_pages
);
5648 if (page_mapped(page
)) {
5649 __mod_lruvec_state(from_vec
, NR_FILE_MAPPED
, -nr_pages
);
5650 __mod_lruvec_state(to_vec
, NR_FILE_MAPPED
, nr_pages
);
5653 if (PageDirty(page
)) {
5654 struct address_space
*mapping
= page_mapping(page
);
5656 if (mapping_can_writeback(mapping
)) {
5657 __mod_lruvec_state(from_vec
, NR_FILE_DIRTY
,
5659 __mod_lruvec_state(to_vec
, NR_FILE_DIRTY
,
5665 if (PageWriteback(page
)) {
5666 __mod_lruvec_state(from_vec
, NR_WRITEBACK
, -nr_pages
);
5667 __mod_lruvec_state(to_vec
, NR_WRITEBACK
, nr_pages
);
5671 * All state has been migrated, let's switch to the new memcg.
5673 * It is safe to change page's memcg here because the page
5674 * is referenced, charged, isolated, and locked: we can't race
5675 * with (un)charging, migration, LRU putback, or anything else
5676 * that would rely on a stable page's memory cgroup.
5678 * Note that lock_page_memcg is a memcg lock, not a page lock,
5679 * to save space. As soon as we switch page's memory cgroup to a
5680 * new memcg that isn't locked, the above state can change
5681 * concurrently again. Make sure we're truly done with it.
5686 css_put(&from
->css
);
5688 page
->memcg_data
= (unsigned long)to
;
5690 __unlock_page_memcg(from
);
5694 local_irq_disable();
5695 mem_cgroup_charge_statistics(to
, page
, nr_pages
);
5696 memcg_check_events(to
, page
);
5697 mem_cgroup_charge_statistics(from
, page
, -nr_pages
);
5698 memcg_check_events(from
, page
);
5707 * get_mctgt_type - get target type of moving charge
5708 * @vma: the vma the pte to be checked belongs
5709 * @addr: the address corresponding to the pte to be checked
5710 * @ptent: the pte to be checked
5711 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5714 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5715 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5716 * move charge. if @target is not NULL, the page is stored in target->page
5717 * with extra refcnt got(Callers should handle it).
5718 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5719 * target for charge migration. if @target is not NULL, the entry is stored
5721 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5722 * (so ZONE_DEVICE page and thus not on the lru).
5723 * For now we such page is charge like a regular page would be as for all
5724 * intent and purposes it is just special memory taking the place of a
5727 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5729 * Called with pte lock held.
5732 static enum mc_target_type
get_mctgt_type(struct vm_area_struct
*vma
,
5733 unsigned long addr
, pte_t ptent
, union mc_target
*target
)
5735 struct page
*page
= NULL
;
5736 enum mc_target_type ret
= MC_TARGET_NONE
;
5737 swp_entry_t ent
= { .val
= 0 };
5739 if (pte_present(ptent
))
5740 page
= mc_handle_present_pte(vma
, addr
, ptent
);
5741 else if (is_swap_pte(ptent
))
5742 page
= mc_handle_swap_pte(vma
, ptent
, &ent
);
5743 else if (pte_none(ptent
))
5744 page
= mc_handle_file_pte(vma
, addr
, ptent
, &ent
);
5746 if (!page
&& !ent
.val
)
5750 * Do only loose check w/o serialization.
5751 * mem_cgroup_move_account() checks the page is valid or
5752 * not under LRU exclusion.
5754 if (page_memcg(page
) == mc
.from
) {
5755 ret
= MC_TARGET_PAGE
;
5756 if (is_device_private_page(page
))
5757 ret
= MC_TARGET_DEVICE
;
5759 target
->page
= page
;
5761 if (!ret
|| !target
)
5765 * There is a swap entry and a page doesn't exist or isn't charged.
5766 * But we cannot move a tail-page in a THP.
5768 if (ent
.val
&& !ret
&& (!page
|| !PageTransCompound(page
)) &&
5769 mem_cgroup_id(mc
.from
) == lookup_swap_cgroup_id(ent
)) {
5770 ret
= MC_TARGET_SWAP
;
5777 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5779 * We don't consider PMD mapped swapping or file mapped pages because THP does
5780 * not support them for now.
5781 * Caller should make sure that pmd_trans_huge(pmd) is true.
5783 static enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5784 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5786 struct page
*page
= NULL
;
5787 enum mc_target_type ret
= MC_TARGET_NONE
;
5789 if (unlikely(is_swap_pmd(pmd
))) {
5790 VM_BUG_ON(thp_migration_supported() &&
5791 !is_pmd_migration_entry(pmd
));
5794 page
= pmd_page(pmd
);
5795 VM_BUG_ON_PAGE(!page
|| !PageHead(page
), page
);
5796 if (!(mc
.flags
& MOVE_ANON
))
5798 if (page_memcg(page
) == mc
.from
) {
5799 ret
= MC_TARGET_PAGE
;
5802 target
->page
= page
;
5808 static inline enum mc_target_type
get_mctgt_type_thp(struct vm_area_struct
*vma
,
5809 unsigned long addr
, pmd_t pmd
, union mc_target
*target
)
5811 return MC_TARGET_NONE
;
5815 static int mem_cgroup_count_precharge_pte_range(pmd_t
*pmd
,
5816 unsigned long addr
, unsigned long end
,
5817 struct mm_walk
*walk
)
5819 struct vm_area_struct
*vma
= walk
->vma
;
5823 ptl
= pmd_trans_huge_lock(pmd
, vma
);
5826 * Note their can not be MC_TARGET_DEVICE for now as we do not
5827 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5828 * this might change.
5830 if (get_mctgt_type_thp(vma
, addr
, *pmd
, NULL
) == MC_TARGET_PAGE
)
5831 mc
.precharge
+= HPAGE_PMD_NR
;
5836 if (pmd_trans_unstable(pmd
))
5838 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
5839 for (; addr
!= end
; pte
++, addr
+= PAGE_SIZE
)
5840 if (get_mctgt_type(vma
, addr
, *pte
, NULL
))
5841 mc
.precharge
++; /* increment precharge temporarily */
5842 pte_unmap_unlock(pte
- 1, ptl
);
5848 static const struct mm_walk_ops precharge_walk_ops
= {
5849 .pmd_entry
= mem_cgroup_count_precharge_pte_range
,
5852 static unsigned long mem_cgroup_count_precharge(struct mm_struct
*mm
)
5854 unsigned long precharge
;
5857 walk_page_range(mm
, 0, mm
->highest_vm_end
, &precharge_walk_ops
, NULL
);
5858 mmap_read_unlock(mm
);
5860 precharge
= mc
.precharge
;
5866 static int mem_cgroup_precharge_mc(struct mm_struct
*mm
)
5868 unsigned long precharge
= mem_cgroup_count_precharge(mm
);
5870 VM_BUG_ON(mc
.moving_task
);
5871 mc
.moving_task
= current
;
5872 return mem_cgroup_do_precharge(precharge
);
5875 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5876 static void __mem_cgroup_clear_mc(void)
5878 struct mem_cgroup
*from
= mc
.from
;
5879 struct mem_cgroup
*to
= mc
.to
;
5881 /* we must uncharge all the leftover precharges from mc.to */
5883 cancel_charge(mc
.to
, mc
.precharge
);
5887 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5888 * we must uncharge here.
5890 if (mc
.moved_charge
) {
5891 cancel_charge(mc
.from
, mc
.moved_charge
);
5892 mc
.moved_charge
= 0;
5894 /* we must fixup refcnts and charges */
5895 if (mc
.moved_swap
) {
5896 /* uncharge swap account from the old cgroup */
5897 if (!mem_cgroup_is_root(mc
.from
))
5898 page_counter_uncharge(&mc
.from
->memsw
, mc
.moved_swap
);
5900 mem_cgroup_id_put_many(mc
.from
, mc
.moved_swap
);
5903 * we charged both to->memory and to->memsw, so we
5904 * should uncharge to->memory.
5906 if (!mem_cgroup_is_root(mc
.to
))
5907 page_counter_uncharge(&mc
.to
->memory
, mc
.moved_swap
);
5911 memcg_oom_recover(from
);
5912 memcg_oom_recover(to
);
5913 wake_up_all(&mc
.waitq
);
5916 static void mem_cgroup_clear_mc(void)
5918 struct mm_struct
*mm
= mc
.mm
;
5921 * we must clear moving_task before waking up waiters at the end of
5924 mc
.moving_task
= NULL
;
5925 __mem_cgroup_clear_mc();
5926 spin_lock(&mc
.lock
);
5930 spin_unlock(&mc
.lock
);
5935 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
5937 struct cgroup_subsys_state
*css
;
5938 struct mem_cgroup
*memcg
= NULL
; /* unneeded init to make gcc happy */
5939 struct mem_cgroup
*from
;
5940 struct task_struct
*leader
, *p
;
5941 struct mm_struct
*mm
;
5942 unsigned long move_flags
;
5945 /* charge immigration isn't supported on the default hierarchy */
5946 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
5950 * Multi-process migrations only happen on the default hierarchy
5951 * where charge immigration is not used. Perform charge
5952 * immigration if @tset contains a leader and whine if there are
5956 cgroup_taskset_for_each_leader(leader
, css
, tset
) {
5959 memcg
= mem_cgroup_from_css(css
);
5965 * We are now committed to this value whatever it is. Changes in this
5966 * tunable will only affect upcoming migrations, not the current one.
5967 * So we need to save it, and keep it going.
5969 move_flags
= READ_ONCE(memcg
->move_charge_at_immigrate
);
5973 from
= mem_cgroup_from_task(p
);
5975 VM_BUG_ON(from
== memcg
);
5977 mm
= get_task_mm(p
);
5980 /* We move charges only when we move a owner of the mm */
5981 if (mm
->owner
== p
) {
5984 VM_BUG_ON(mc
.precharge
);
5985 VM_BUG_ON(mc
.moved_charge
);
5986 VM_BUG_ON(mc
.moved_swap
);
5988 spin_lock(&mc
.lock
);
5992 mc
.flags
= move_flags
;
5993 spin_unlock(&mc
.lock
);
5994 /* We set mc.moving_task later */
5996 ret
= mem_cgroup_precharge_mc(mm
);
5998 mem_cgroup_clear_mc();
6005 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
6008 mem_cgroup_clear_mc();
6011 static int mem_cgroup_move_charge_pte_range(pmd_t
*pmd
,
6012 unsigned long addr
, unsigned long end
,
6013 struct mm_walk
*walk
)
6016 struct vm_area_struct
*vma
= walk
->vma
;
6019 enum mc_target_type target_type
;
6020 union mc_target target
;
6023 ptl
= pmd_trans_huge_lock(pmd
, vma
);
6025 if (mc
.precharge
< HPAGE_PMD_NR
) {
6029 target_type
= get_mctgt_type_thp(vma
, addr
, *pmd
, &target
);
6030 if (target_type
== MC_TARGET_PAGE
) {
6032 if (!isolate_lru_page(page
)) {
6033 if (!mem_cgroup_move_account(page
, true,
6035 mc
.precharge
-= HPAGE_PMD_NR
;
6036 mc
.moved_charge
+= HPAGE_PMD_NR
;
6038 putback_lru_page(page
);
6041 } else if (target_type
== MC_TARGET_DEVICE
) {
6043 if (!mem_cgroup_move_account(page
, true,
6045 mc
.precharge
-= HPAGE_PMD_NR
;
6046 mc
.moved_charge
+= HPAGE_PMD_NR
;
6054 if (pmd_trans_unstable(pmd
))
6057 pte
= pte_offset_map_lock(vma
->vm_mm
, pmd
, addr
, &ptl
);
6058 for (; addr
!= end
; addr
+= PAGE_SIZE
) {
6059 pte_t ptent
= *(pte
++);
6060 bool device
= false;
6066 switch (get_mctgt_type(vma
, addr
, ptent
, &target
)) {
6067 case MC_TARGET_DEVICE
:
6070 case MC_TARGET_PAGE
:
6073 * We can have a part of the split pmd here. Moving it
6074 * can be done but it would be too convoluted so simply
6075 * ignore such a partial THP and keep it in original
6076 * memcg. There should be somebody mapping the head.
6078 if (PageTransCompound(page
))
6080 if (!device
&& isolate_lru_page(page
))
6082 if (!mem_cgroup_move_account(page
, false,
6085 /* we uncharge from mc.from later. */
6089 putback_lru_page(page
);
6090 put
: /* get_mctgt_type() gets the page */
6093 case MC_TARGET_SWAP
:
6095 if (!mem_cgroup_move_swap_account(ent
, mc
.from
, mc
.to
)) {
6097 mem_cgroup_id_get_many(mc
.to
, 1);
6098 /* we fixup other refcnts and charges later. */
6106 pte_unmap_unlock(pte
- 1, ptl
);
6111 * We have consumed all precharges we got in can_attach().
6112 * We try charge one by one, but don't do any additional
6113 * charges to mc.to if we have failed in charge once in attach()
6116 ret
= mem_cgroup_do_precharge(1);
6124 static const struct mm_walk_ops charge_walk_ops
= {
6125 .pmd_entry
= mem_cgroup_move_charge_pte_range
,
6128 static void mem_cgroup_move_charge(void)
6130 lru_add_drain_all();
6132 * Signal lock_page_memcg() to take the memcg's move_lock
6133 * while we're moving its pages to another memcg. Then wait
6134 * for already started RCU-only updates to finish.
6136 atomic_inc(&mc
.from
->moving_account
);
6139 if (unlikely(!mmap_read_trylock(mc
.mm
))) {
6141 * Someone who are holding the mmap_lock might be waiting in
6142 * waitq. So we cancel all extra charges, wake up all waiters,
6143 * and retry. Because we cancel precharges, we might not be able
6144 * to move enough charges, but moving charge is a best-effort
6145 * feature anyway, so it wouldn't be a big problem.
6147 __mem_cgroup_clear_mc();
6152 * When we have consumed all precharges and failed in doing
6153 * additional charge, the page walk just aborts.
6155 walk_page_range(mc
.mm
, 0, mc
.mm
->highest_vm_end
, &charge_walk_ops
,
6158 mmap_read_unlock(mc
.mm
);
6159 atomic_dec(&mc
.from
->moving_account
);
6162 static void mem_cgroup_move_task(void)
6165 mem_cgroup_move_charge();
6166 mem_cgroup_clear_mc();
6169 #else /* !CONFIG_MMU */
6170 static int mem_cgroup_can_attach(struct cgroup_taskset
*tset
)
6174 static void mem_cgroup_cancel_attach(struct cgroup_taskset
*tset
)
6177 static void mem_cgroup_move_task(void)
6182 static int seq_puts_memcg_tunable(struct seq_file
*m
, unsigned long value
)
6184 if (value
== PAGE_COUNTER_MAX
)
6185 seq_puts(m
, "max\n");
6187 seq_printf(m
, "%llu\n", (u64
)value
* PAGE_SIZE
);
6192 static u64
memory_current_read(struct cgroup_subsys_state
*css
,
6195 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
6197 return (u64
)page_counter_read(&memcg
->memory
) * PAGE_SIZE
;
6200 static int memory_min_show(struct seq_file
*m
, void *v
)
6202 return seq_puts_memcg_tunable(m
,
6203 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.min
));
6206 static ssize_t
memory_min_write(struct kernfs_open_file
*of
,
6207 char *buf
, size_t nbytes
, loff_t off
)
6209 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6213 buf
= strstrip(buf
);
6214 err
= page_counter_memparse(buf
, "max", &min
);
6218 page_counter_set_min(&memcg
->memory
, min
);
6223 static int memory_low_show(struct seq_file
*m
, void *v
)
6225 return seq_puts_memcg_tunable(m
,
6226 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.low
));
6229 static ssize_t
memory_low_write(struct kernfs_open_file
*of
,
6230 char *buf
, size_t nbytes
, loff_t off
)
6232 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6236 buf
= strstrip(buf
);
6237 err
= page_counter_memparse(buf
, "max", &low
);
6241 page_counter_set_low(&memcg
->memory
, low
);
6246 static int memory_high_show(struct seq_file
*m
, void *v
)
6248 return seq_puts_memcg_tunable(m
,
6249 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.high
));
6252 static ssize_t
memory_high_write(struct kernfs_open_file
*of
,
6253 char *buf
, size_t nbytes
, loff_t off
)
6255 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6256 unsigned int nr_retries
= MAX_RECLAIM_RETRIES
;
6257 bool drained
= false;
6261 buf
= strstrip(buf
);
6262 err
= page_counter_memparse(buf
, "max", &high
);
6266 page_counter_set_high(&memcg
->memory
, high
);
6269 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6270 unsigned long reclaimed
;
6272 if (nr_pages
<= high
)
6275 if (signal_pending(current
))
6279 drain_all_stock(memcg
);
6284 reclaimed
= try_to_free_mem_cgroup_pages(memcg
, nr_pages
- high
,
6287 if (!reclaimed
&& !nr_retries
--)
6291 memcg_wb_domain_size_changed(memcg
);
6295 static int memory_max_show(struct seq_file
*m
, void *v
)
6297 return seq_puts_memcg_tunable(m
,
6298 READ_ONCE(mem_cgroup_from_seq(m
)->memory
.max
));
6301 static ssize_t
memory_max_write(struct kernfs_open_file
*of
,
6302 char *buf
, size_t nbytes
, loff_t off
)
6304 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6305 unsigned int nr_reclaims
= MAX_RECLAIM_RETRIES
;
6306 bool drained
= false;
6310 buf
= strstrip(buf
);
6311 err
= page_counter_memparse(buf
, "max", &max
);
6315 xchg(&memcg
->memory
.max
, max
);
6318 unsigned long nr_pages
= page_counter_read(&memcg
->memory
);
6320 if (nr_pages
<= max
)
6323 if (signal_pending(current
))
6327 drain_all_stock(memcg
);
6333 if (!try_to_free_mem_cgroup_pages(memcg
, nr_pages
- max
,
6339 memcg_memory_event(memcg
, MEMCG_OOM
);
6340 if (!mem_cgroup_out_of_memory(memcg
, GFP_KERNEL
, 0))
6344 memcg_wb_domain_size_changed(memcg
);
6348 static void __memory_events_show(struct seq_file
*m
, atomic_long_t
*events
)
6350 seq_printf(m
, "low %lu\n", atomic_long_read(&events
[MEMCG_LOW
]));
6351 seq_printf(m
, "high %lu\n", atomic_long_read(&events
[MEMCG_HIGH
]));
6352 seq_printf(m
, "max %lu\n", atomic_long_read(&events
[MEMCG_MAX
]));
6353 seq_printf(m
, "oom %lu\n", atomic_long_read(&events
[MEMCG_OOM
]));
6354 seq_printf(m
, "oom_kill %lu\n",
6355 atomic_long_read(&events
[MEMCG_OOM_KILL
]));
6358 static int memory_events_show(struct seq_file
*m
, void *v
)
6360 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6362 __memory_events_show(m
, memcg
->memory_events
);
6366 static int memory_events_local_show(struct seq_file
*m
, void *v
)
6368 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6370 __memory_events_show(m
, memcg
->memory_events_local
);
6374 static int memory_stat_show(struct seq_file
*m
, void *v
)
6376 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6379 buf
= memory_stat_format(memcg
);
6388 static inline unsigned long lruvec_page_state_output(struct lruvec
*lruvec
,
6391 return lruvec_page_state(lruvec
, item
) * memcg_page_state_unit(item
);
6394 static int memory_numa_stat_show(struct seq_file
*m
, void *v
)
6397 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6399 for (i
= 0; i
< ARRAY_SIZE(memory_stats
); i
++) {
6402 if (memory_stats
[i
].idx
>= NR_VM_NODE_STAT_ITEMS
)
6405 seq_printf(m
, "%s", memory_stats
[i
].name
);
6406 for_each_node_state(nid
, N_MEMORY
) {
6408 struct lruvec
*lruvec
;
6410 lruvec
= mem_cgroup_lruvec(memcg
, NODE_DATA(nid
));
6411 size
= lruvec_page_state_output(lruvec
,
6412 memory_stats
[i
].idx
);
6413 seq_printf(m
, " N%d=%llu", nid
, size
);
6422 static int memory_oom_group_show(struct seq_file
*m
, void *v
)
6424 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
6426 seq_printf(m
, "%d\n", memcg
->oom_group
);
6431 static ssize_t
memory_oom_group_write(struct kernfs_open_file
*of
,
6432 char *buf
, size_t nbytes
, loff_t off
)
6434 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
6437 buf
= strstrip(buf
);
6441 ret
= kstrtoint(buf
, 0, &oom_group
);
6445 if (oom_group
!= 0 && oom_group
!= 1)
6448 memcg
->oom_group
= oom_group
;
6453 static struct cftype memory_files
[] = {
6456 .flags
= CFTYPE_NOT_ON_ROOT
,
6457 .read_u64
= memory_current_read
,
6461 .flags
= CFTYPE_NOT_ON_ROOT
,
6462 .seq_show
= memory_min_show
,
6463 .write
= memory_min_write
,
6467 .flags
= CFTYPE_NOT_ON_ROOT
,
6468 .seq_show
= memory_low_show
,
6469 .write
= memory_low_write
,
6473 .flags
= CFTYPE_NOT_ON_ROOT
,
6474 .seq_show
= memory_high_show
,
6475 .write
= memory_high_write
,
6479 .flags
= CFTYPE_NOT_ON_ROOT
,
6480 .seq_show
= memory_max_show
,
6481 .write
= memory_max_write
,
6485 .flags
= CFTYPE_NOT_ON_ROOT
,
6486 .file_offset
= offsetof(struct mem_cgroup
, events_file
),
6487 .seq_show
= memory_events_show
,
6490 .name
= "events.local",
6491 .flags
= CFTYPE_NOT_ON_ROOT
,
6492 .file_offset
= offsetof(struct mem_cgroup
, events_local_file
),
6493 .seq_show
= memory_events_local_show
,
6497 .seq_show
= memory_stat_show
,
6501 .name
= "numa_stat",
6502 .seq_show
= memory_numa_stat_show
,
6506 .name
= "oom.group",
6507 .flags
= CFTYPE_NOT_ON_ROOT
| CFTYPE_NS_DELEGATABLE
,
6508 .seq_show
= memory_oom_group_show
,
6509 .write
= memory_oom_group_write
,
6514 struct cgroup_subsys memory_cgrp_subsys
= {
6515 .css_alloc
= mem_cgroup_css_alloc
,
6516 .css_online
= mem_cgroup_css_online
,
6517 .css_offline
= mem_cgroup_css_offline
,
6518 .css_released
= mem_cgroup_css_released
,
6519 .css_free
= mem_cgroup_css_free
,
6520 .css_reset
= mem_cgroup_css_reset
,
6521 .css_rstat_flush
= mem_cgroup_css_rstat_flush
,
6522 .can_attach
= mem_cgroup_can_attach
,
6523 .cancel_attach
= mem_cgroup_cancel_attach
,
6524 .post_attach
= mem_cgroup_move_task
,
6525 .dfl_cftypes
= memory_files
,
6526 .legacy_cftypes
= mem_cgroup_legacy_files
,
6531 * This function calculates an individual cgroup's effective
6532 * protection which is derived from its own memory.min/low, its
6533 * parent's and siblings' settings, as well as the actual memory
6534 * distribution in the tree.
6536 * The following rules apply to the effective protection values:
6538 * 1. At the first level of reclaim, effective protection is equal to
6539 * the declared protection in memory.min and memory.low.
6541 * 2. To enable safe delegation of the protection configuration, at
6542 * subsequent levels the effective protection is capped to the
6543 * parent's effective protection.
6545 * 3. To make complex and dynamic subtrees easier to configure, the
6546 * user is allowed to overcommit the declared protection at a given
6547 * level. If that is the case, the parent's effective protection is
6548 * distributed to the children in proportion to how much protection
6549 * they have declared and how much of it they are utilizing.
6551 * This makes distribution proportional, but also work-conserving:
6552 * if one cgroup claims much more protection than it uses memory,
6553 * the unused remainder is available to its siblings.
6555 * 4. Conversely, when the declared protection is undercommitted at a
6556 * given level, the distribution of the larger parental protection
6557 * budget is NOT proportional. A cgroup's protection from a sibling
6558 * is capped to its own memory.min/low setting.
6560 * 5. However, to allow protecting recursive subtrees from each other
6561 * without having to declare each individual cgroup's fixed share
6562 * of the ancestor's claim to protection, any unutilized -
6563 * "floating" - protection from up the tree is distributed in
6564 * proportion to each cgroup's *usage*. This makes the protection
6565 * neutral wrt sibling cgroups and lets them compete freely over
6566 * the shared parental protection budget, but it protects the
6567 * subtree as a whole from neighboring subtrees.
6569 * Note that 4. and 5. are not in conflict: 4. is about protecting
6570 * against immediate siblings whereas 5. is about protecting against
6571 * neighboring subtrees.
6573 static unsigned long effective_protection(unsigned long usage
,
6574 unsigned long parent_usage
,
6575 unsigned long setting
,
6576 unsigned long parent_effective
,
6577 unsigned long siblings_protected
)
6579 unsigned long protected;
6582 protected = min(usage
, setting
);
6584 * If all cgroups at this level combined claim and use more
6585 * protection then what the parent affords them, distribute
6586 * shares in proportion to utilization.
6588 * We are using actual utilization rather than the statically
6589 * claimed protection in order to be work-conserving: claimed
6590 * but unused protection is available to siblings that would
6591 * otherwise get a smaller chunk than what they claimed.
6593 if (siblings_protected
> parent_effective
)
6594 return protected * parent_effective
/ siblings_protected
;
6597 * Ok, utilized protection of all children is within what the
6598 * parent affords them, so we know whatever this child claims
6599 * and utilizes is effectively protected.
6601 * If there is unprotected usage beyond this value, reclaim
6602 * will apply pressure in proportion to that amount.
6604 * If there is unutilized protection, the cgroup will be fully
6605 * shielded from reclaim, but we do return a smaller value for
6606 * protection than what the group could enjoy in theory. This
6607 * is okay. With the overcommit distribution above, effective
6608 * protection is always dependent on how memory is actually
6609 * consumed among the siblings anyway.
6614 * If the children aren't claiming (all of) the protection
6615 * afforded to them by the parent, distribute the remainder in
6616 * proportion to the (unprotected) memory of each cgroup. That
6617 * way, cgroups that aren't explicitly prioritized wrt each
6618 * other compete freely over the allowance, but they are
6619 * collectively protected from neighboring trees.
6621 * We're using unprotected memory for the weight so that if
6622 * some cgroups DO claim explicit protection, we don't protect
6623 * the same bytes twice.
6625 * Check both usage and parent_usage against the respective
6626 * protected values. One should imply the other, but they
6627 * aren't read atomically - make sure the division is sane.
6629 if (!(cgrp_dfl_root
.flags
& CGRP_ROOT_MEMORY_RECURSIVE_PROT
))
6631 if (parent_effective
> siblings_protected
&&
6632 parent_usage
> siblings_protected
&&
6633 usage
> protected) {
6634 unsigned long unclaimed
;
6636 unclaimed
= parent_effective
- siblings_protected
;
6637 unclaimed
*= usage
- protected;
6638 unclaimed
/= parent_usage
- siblings_protected
;
6647 * mem_cgroup_calculate_protection - check if memory consumption is in the normal range
6648 * @root: the top ancestor of the sub-tree being checked
6649 * @memcg: the memory cgroup to check
6651 * WARNING: This function is not stateless! It can only be used as part
6652 * of a top-down tree iteration, not for isolated queries.
6654 void mem_cgroup_calculate_protection(struct mem_cgroup
*root
,
6655 struct mem_cgroup
*memcg
)
6657 unsigned long usage
, parent_usage
;
6658 struct mem_cgroup
*parent
;
6660 if (mem_cgroup_disabled())
6664 root
= root_mem_cgroup
;
6667 * Effective values of the reclaim targets are ignored so they
6668 * can be stale. Have a look at mem_cgroup_protection for more
6670 * TODO: calculation should be more robust so that we do not need
6671 * that special casing.
6676 usage
= page_counter_read(&memcg
->memory
);
6680 parent
= parent_mem_cgroup(memcg
);
6681 /* No parent means a non-hierarchical mode on v1 memcg */
6685 if (parent
== root
) {
6686 memcg
->memory
.emin
= READ_ONCE(memcg
->memory
.min
);
6687 memcg
->memory
.elow
= READ_ONCE(memcg
->memory
.low
);
6691 parent_usage
= page_counter_read(&parent
->memory
);
6693 WRITE_ONCE(memcg
->memory
.emin
, effective_protection(usage
, parent_usage
,
6694 READ_ONCE(memcg
->memory
.min
),
6695 READ_ONCE(parent
->memory
.emin
),
6696 atomic_long_read(&parent
->memory
.children_min_usage
)));
6698 WRITE_ONCE(memcg
->memory
.elow
, effective_protection(usage
, parent_usage
,
6699 READ_ONCE(memcg
->memory
.low
),
6700 READ_ONCE(parent
->memory
.elow
),
6701 atomic_long_read(&parent
->memory
.children_low_usage
)));
6704 static int __mem_cgroup_charge(struct page
*page
, struct mem_cgroup
*memcg
,
6707 unsigned int nr_pages
= thp_nr_pages(page
);
6710 ret
= try_charge(memcg
, gfp
, nr_pages
);
6714 css_get(&memcg
->css
);
6715 commit_charge(page
, memcg
);
6717 local_irq_disable();
6718 mem_cgroup_charge_statistics(memcg
, page
, nr_pages
);
6719 memcg_check_events(memcg
, page
);
6726 * mem_cgroup_charge - charge a newly allocated page to a cgroup
6727 * @page: page to charge
6728 * @mm: mm context of the victim
6729 * @gfp_mask: reclaim mode
6731 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6732 * pages according to @gfp_mask if necessary. if @mm is NULL, try to
6733 * charge to the active memcg.
6735 * Do not use this for pages allocated for swapin.
6737 * Returns 0 on success. Otherwise, an error code is returned.
6739 int mem_cgroup_charge(struct page
*page
, struct mm_struct
*mm
, gfp_t gfp_mask
)
6741 struct mem_cgroup
*memcg
;
6744 if (mem_cgroup_disabled())
6747 memcg
= get_mem_cgroup_from_mm(mm
);
6748 ret
= __mem_cgroup_charge(page
, memcg
, gfp_mask
);
6749 css_put(&memcg
->css
);
6755 * mem_cgroup_swapin_charge_page - charge a newly allocated page for swapin
6756 * @page: page to charge
6757 * @mm: mm context of the victim
6758 * @gfp: reclaim mode
6759 * @entry: swap entry for which the page is allocated
6761 * This function charges a page allocated for swapin. Please call this before
6762 * adding the page to the swapcache.
6764 * Returns 0 on success. Otherwise, an error code is returned.
6766 int mem_cgroup_swapin_charge_page(struct page
*page
, struct mm_struct
*mm
,
6767 gfp_t gfp
, swp_entry_t entry
)
6769 struct mem_cgroup
*memcg
;
6773 if (mem_cgroup_disabled())
6776 id
= lookup_swap_cgroup_id(entry
);
6778 memcg
= mem_cgroup_from_id(id
);
6779 if (!memcg
|| !css_tryget_online(&memcg
->css
))
6780 memcg
= get_mem_cgroup_from_mm(mm
);
6783 ret
= __mem_cgroup_charge(page
, memcg
, gfp
);
6785 css_put(&memcg
->css
);
6790 * mem_cgroup_swapin_uncharge_swap - uncharge swap slot
6791 * @entry: swap entry for which the page is charged
6793 * Call this function after successfully adding the charged page to swapcache.
6795 * Note: This function assumes the page for which swap slot is being uncharged
6798 void mem_cgroup_swapin_uncharge_swap(swp_entry_t entry
)
6801 * Cgroup1's unified memory+swap counter has been charged with the
6802 * new swapcache page, finish the transfer by uncharging the swap
6803 * slot. The swap slot would also get uncharged when it dies, but
6804 * it can stick around indefinitely and we'd count the page twice
6807 * Cgroup2 has separate resource counters for memory and swap,
6808 * so this is a non-issue here. Memory and swap charge lifetimes
6809 * correspond 1:1 to page and swap slot lifetimes: we charge the
6810 * page to memory here, and uncharge swap when the slot is freed.
6812 if (!mem_cgroup_disabled() && do_memsw_account()) {
6814 * The swap entry might not get freed for a long time,
6815 * let's not wait for it. The page already received a
6816 * memory+swap charge, drop the swap entry duplicate.
6818 mem_cgroup_uncharge_swap(entry
, 1);
6822 struct uncharge_gather
{
6823 struct mem_cgroup
*memcg
;
6824 unsigned long nr_memory
;
6825 unsigned long pgpgout
;
6826 unsigned long nr_kmem
;
6827 struct page
*dummy_page
;
6830 static inline void uncharge_gather_clear(struct uncharge_gather
*ug
)
6832 memset(ug
, 0, sizeof(*ug
));
6835 static void uncharge_batch(const struct uncharge_gather
*ug
)
6837 unsigned long flags
;
6839 if (ug
->nr_memory
) {
6840 page_counter_uncharge(&ug
->memcg
->memory
, ug
->nr_memory
);
6841 if (do_memsw_account())
6842 page_counter_uncharge(&ug
->memcg
->memsw
, ug
->nr_memory
);
6843 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && ug
->nr_kmem
)
6844 page_counter_uncharge(&ug
->memcg
->kmem
, ug
->nr_kmem
);
6845 memcg_oom_recover(ug
->memcg
);
6848 local_irq_save(flags
);
6849 __count_memcg_events(ug
->memcg
, PGPGOUT
, ug
->pgpgout
);
6850 __this_cpu_add(ug
->memcg
->vmstats_percpu
->nr_page_events
, ug
->nr_memory
);
6851 memcg_check_events(ug
->memcg
, ug
->dummy_page
);
6852 local_irq_restore(flags
);
6854 /* drop reference from uncharge_page */
6855 css_put(&ug
->memcg
->css
);
6858 static void uncharge_page(struct page
*page
, struct uncharge_gather
*ug
)
6860 unsigned long nr_pages
;
6861 struct mem_cgroup
*memcg
;
6862 struct obj_cgroup
*objcg
;
6863 bool use_objcg
= PageMemcgKmem(page
);
6865 VM_BUG_ON_PAGE(PageLRU(page
), page
);
6868 * Nobody should be changing or seriously looking at
6869 * page memcg or objcg at this point, we have fully
6870 * exclusive access to the page.
6873 objcg
= __page_objcg(page
);
6875 * This get matches the put at the end of the function and
6876 * kmem pages do not hold memcg references anymore.
6878 memcg
= get_mem_cgroup_from_objcg(objcg
);
6880 memcg
= __page_memcg(page
);
6886 if (ug
->memcg
!= memcg
) {
6889 uncharge_gather_clear(ug
);
6892 ug
->dummy_page
= page
;
6894 /* pairs with css_put in uncharge_batch */
6895 css_get(&memcg
->css
);
6898 nr_pages
= compound_nr(page
);
6901 ug
->nr_memory
+= nr_pages
;
6902 ug
->nr_kmem
+= nr_pages
;
6904 page
->memcg_data
= 0;
6905 obj_cgroup_put(objcg
);
6907 /* LRU pages aren't accounted at the root level */
6908 if (!mem_cgroup_is_root(memcg
))
6909 ug
->nr_memory
+= nr_pages
;
6912 page
->memcg_data
= 0;
6915 css_put(&memcg
->css
);
6919 * mem_cgroup_uncharge - uncharge a page
6920 * @page: page to uncharge
6922 * Uncharge a page previously charged with mem_cgroup_charge().
6924 void mem_cgroup_uncharge(struct page
*page
)
6926 struct uncharge_gather ug
;
6928 if (mem_cgroup_disabled())
6931 /* Don't touch page->lru of any random page, pre-check: */
6932 if (!page_memcg(page
))
6935 uncharge_gather_clear(&ug
);
6936 uncharge_page(page
, &ug
);
6937 uncharge_batch(&ug
);
6941 * mem_cgroup_uncharge_list - uncharge a list of page
6942 * @page_list: list of pages to uncharge
6944 * Uncharge a list of pages previously charged with
6945 * mem_cgroup_charge().
6947 void mem_cgroup_uncharge_list(struct list_head
*page_list
)
6949 struct uncharge_gather ug
;
6952 if (mem_cgroup_disabled())
6955 uncharge_gather_clear(&ug
);
6956 list_for_each_entry(page
, page_list
, lru
)
6957 uncharge_page(page
, &ug
);
6959 uncharge_batch(&ug
);
6963 * mem_cgroup_migrate - charge a page's replacement
6964 * @oldpage: currently circulating page
6965 * @newpage: replacement page
6967 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6968 * be uncharged upon free.
6970 * Both pages must be locked, @newpage->mapping must be set up.
6972 void mem_cgroup_migrate(struct page
*oldpage
, struct page
*newpage
)
6974 struct mem_cgroup
*memcg
;
6975 unsigned int nr_pages
;
6976 unsigned long flags
;
6978 VM_BUG_ON_PAGE(!PageLocked(oldpage
), oldpage
);
6979 VM_BUG_ON_PAGE(!PageLocked(newpage
), newpage
);
6980 VM_BUG_ON_PAGE(PageAnon(oldpage
) != PageAnon(newpage
), newpage
);
6981 VM_BUG_ON_PAGE(PageTransHuge(oldpage
) != PageTransHuge(newpage
),
6984 if (mem_cgroup_disabled())
6987 /* Page cache replacement: new page already charged? */
6988 if (page_memcg(newpage
))
6991 memcg
= page_memcg(oldpage
);
6992 VM_WARN_ON_ONCE_PAGE(!memcg
, oldpage
);
6996 /* Force-charge the new page. The old one will be freed soon */
6997 nr_pages
= thp_nr_pages(newpage
);
6999 if (!mem_cgroup_is_root(memcg
)) {
7000 page_counter_charge(&memcg
->memory
, nr_pages
);
7001 if (do_memsw_account())
7002 page_counter_charge(&memcg
->memsw
, nr_pages
);
7005 css_get(&memcg
->css
);
7006 commit_charge(newpage
, memcg
);
7008 local_irq_save(flags
);
7009 mem_cgroup_charge_statistics(memcg
, newpage
, nr_pages
);
7010 memcg_check_events(memcg
, newpage
);
7011 local_irq_restore(flags
);
7014 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key
);
7015 EXPORT_SYMBOL(memcg_sockets_enabled_key
);
7017 void mem_cgroup_sk_alloc(struct sock
*sk
)
7019 struct mem_cgroup
*memcg
;
7021 if (!mem_cgroup_sockets_enabled
)
7024 /* Do not associate the sock with unrelated interrupted task's memcg. */
7029 memcg
= mem_cgroup_from_task(current
);
7030 if (memcg
== root_mem_cgroup
)
7032 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
) && !memcg
->tcpmem_active
)
7034 if (css_tryget(&memcg
->css
))
7035 sk
->sk_memcg
= memcg
;
7040 void mem_cgroup_sk_free(struct sock
*sk
)
7043 css_put(&sk
->sk_memcg
->css
);
7047 * mem_cgroup_charge_skmem - charge socket memory
7048 * @memcg: memcg to charge
7049 * @nr_pages: number of pages to charge
7051 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
7052 * @memcg's configured limit, %false if the charge had to be forced.
7054 bool mem_cgroup_charge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
7056 gfp_t gfp_mask
= GFP_KERNEL
;
7058 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
7059 struct page_counter
*fail
;
7061 if (page_counter_try_charge(&memcg
->tcpmem
, nr_pages
, &fail
)) {
7062 memcg
->tcpmem_pressure
= 0;
7065 page_counter_charge(&memcg
->tcpmem
, nr_pages
);
7066 memcg
->tcpmem_pressure
= 1;
7070 /* Don't block in the packet receive path */
7072 gfp_mask
= GFP_NOWAIT
;
7074 mod_memcg_state(memcg
, MEMCG_SOCK
, nr_pages
);
7076 if (try_charge(memcg
, gfp_mask
, nr_pages
) == 0)
7079 try_charge(memcg
, gfp_mask
|__GFP_NOFAIL
, nr_pages
);
7084 * mem_cgroup_uncharge_skmem - uncharge socket memory
7085 * @memcg: memcg to uncharge
7086 * @nr_pages: number of pages to uncharge
7088 void mem_cgroup_uncharge_skmem(struct mem_cgroup
*memcg
, unsigned int nr_pages
)
7090 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
)) {
7091 page_counter_uncharge(&memcg
->tcpmem
, nr_pages
);
7095 mod_memcg_state(memcg
, MEMCG_SOCK
, -nr_pages
);
7097 refill_stock(memcg
, nr_pages
);
7100 static int __init
cgroup_memory(char *s
)
7104 while ((token
= strsep(&s
, ",")) != NULL
) {
7107 if (!strcmp(token
, "nosocket"))
7108 cgroup_memory_nosocket
= true;
7109 if (!strcmp(token
, "nokmem"))
7110 cgroup_memory_nokmem
= true;
7114 __setup("cgroup.memory=", cgroup_memory
);
7117 * subsys_initcall() for memory controller.
7119 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
7120 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
7121 * basically everything that doesn't depend on a specific mem_cgroup structure
7122 * should be initialized from here.
7124 static int __init
mem_cgroup_init(void)
7129 * Currently s32 type (can refer to struct batched_lruvec_stat) is
7130 * used for per-memcg-per-cpu caching of per-node statistics. In order
7131 * to work fine, we should make sure that the overfill threshold can't
7132 * exceed S32_MAX / PAGE_SIZE.
7134 BUILD_BUG_ON(MEMCG_CHARGE_BATCH
> S32_MAX
/ PAGE_SIZE
);
7136 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD
, "mm/memctrl:dead", NULL
,
7137 memcg_hotplug_cpu_dead
);
7139 for_each_possible_cpu(cpu
)
7140 INIT_WORK(&per_cpu_ptr(&memcg_stock
, cpu
)->work
,
7143 for_each_node(node
) {
7144 struct mem_cgroup_tree_per_node
*rtpn
;
7146 rtpn
= kzalloc_node(sizeof(*rtpn
), GFP_KERNEL
,
7147 node_online(node
) ? node
: NUMA_NO_NODE
);
7149 rtpn
->rb_root
= RB_ROOT
;
7150 rtpn
->rb_rightmost
= NULL
;
7151 spin_lock_init(&rtpn
->lock
);
7152 soft_limit_tree
.rb_tree_per_node
[node
] = rtpn
;
7157 subsys_initcall(mem_cgroup_init
);
7159 #ifdef CONFIG_MEMCG_SWAP
7160 static struct mem_cgroup
*mem_cgroup_id_get_online(struct mem_cgroup
*memcg
)
7162 while (!refcount_inc_not_zero(&memcg
->id
.ref
)) {
7164 * The root cgroup cannot be destroyed, so it's refcount must
7167 if (WARN_ON_ONCE(memcg
== root_mem_cgroup
)) {
7171 memcg
= parent_mem_cgroup(memcg
);
7173 memcg
= root_mem_cgroup
;
7179 * mem_cgroup_swapout - transfer a memsw charge to swap
7180 * @page: page whose memsw charge to transfer
7181 * @entry: swap entry to move the charge to
7183 * Transfer the memsw charge of @page to @entry.
7185 void mem_cgroup_swapout(struct page
*page
, swp_entry_t entry
)
7187 struct mem_cgroup
*memcg
, *swap_memcg
;
7188 unsigned int nr_entries
;
7189 unsigned short oldid
;
7191 VM_BUG_ON_PAGE(PageLRU(page
), page
);
7192 VM_BUG_ON_PAGE(page_count(page
), page
);
7194 if (mem_cgroup_disabled())
7197 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7200 memcg
= page_memcg(page
);
7202 VM_WARN_ON_ONCE_PAGE(!memcg
, page
);
7207 * In case the memcg owning these pages has been offlined and doesn't
7208 * have an ID allocated to it anymore, charge the closest online
7209 * ancestor for the swap instead and transfer the memory+swap charge.
7211 swap_memcg
= mem_cgroup_id_get_online(memcg
);
7212 nr_entries
= thp_nr_pages(page
);
7213 /* Get references for the tail pages, too */
7215 mem_cgroup_id_get_many(swap_memcg
, nr_entries
- 1);
7216 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(swap_memcg
),
7218 VM_BUG_ON_PAGE(oldid
, page
);
7219 mod_memcg_state(swap_memcg
, MEMCG_SWAP
, nr_entries
);
7221 page
->memcg_data
= 0;
7223 if (!mem_cgroup_is_root(memcg
))
7224 page_counter_uncharge(&memcg
->memory
, nr_entries
);
7226 if (!cgroup_memory_noswap
&& memcg
!= swap_memcg
) {
7227 if (!mem_cgroup_is_root(swap_memcg
))
7228 page_counter_charge(&swap_memcg
->memsw
, nr_entries
);
7229 page_counter_uncharge(&memcg
->memsw
, nr_entries
);
7233 * Interrupts should be disabled here because the caller holds the
7234 * i_pages lock which is taken with interrupts-off. It is
7235 * important here to have the interrupts disabled because it is the
7236 * only synchronisation we have for updating the per-CPU variables.
7238 VM_BUG_ON(!irqs_disabled());
7239 mem_cgroup_charge_statistics(memcg
, page
, -nr_entries
);
7240 memcg_check_events(memcg
, page
);
7242 css_put(&memcg
->css
);
7246 * mem_cgroup_try_charge_swap - try charging swap space for a page
7247 * @page: page being added to swap
7248 * @entry: swap entry to charge
7250 * Try to charge @page's memcg for the swap space at @entry.
7252 * Returns 0 on success, -ENOMEM on failure.
7254 int mem_cgroup_try_charge_swap(struct page
*page
, swp_entry_t entry
)
7256 unsigned int nr_pages
= thp_nr_pages(page
);
7257 struct page_counter
*counter
;
7258 struct mem_cgroup
*memcg
;
7259 unsigned short oldid
;
7261 if (mem_cgroup_disabled())
7264 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7267 memcg
= page_memcg(page
);
7269 VM_WARN_ON_ONCE_PAGE(!memcg
, page
);
7274 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7278 memcg
= mem_cgroup_id_get_online(memcg
);
7280 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
) &&
7281 !page_counter_try_charge(&memcg
->swap
, nr_pages
, &counter
)) {
7282 memcg_memory_event(memcg
, MEMCG_SWAP_MAX
);
7283 memcg_memory_event(memcg
, MEMCG_SWAP_FAIL
);
7284 mem_cgroup_id_put(memcg
);
7288 /* Get references for the tail pages, too */
7290 mem_cgroup_id_get_many(memcg
, nr_pages
- 1);
7291 oldid
= swap_cgroup_record(entry
, mem_cgroup_id(memcg
), nr_pages
);
7292 VM_BUG_ON_PAGE(oldid
, page
);
7293 mod_memcg_state(memcg
, MEMCG_SWAP
, nr_pages
);
7299 * mem_cgroup_uncharge_swap - uncharge swap space
7300 * @entry: swap entry to uncharge
7301 * @nr_pages: the amount of swap space to uncharge
7303 void mem_cgroup_uncharge_swap(swp_entry_t entry
, unsigned int nr_pages
)
7305 struct mem_cgroup
*memcg
;
7308 id
= swap_cgroup_record(entry
, 0, nr_pages
);
7310 memcg
= mem_cgroup_from_id(id
);
7312 if (!cgroup_memory_noswap
&& !mem_cgroup_is_root(memcg
)) {
7313 if (cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7314 page_counter_uncharge(&memcg
->swap
, nr_pages
);
7316 page_counter_uncharge(&memcg
->memsw
, nr_pages
);
7318 mod_memcg_state(memcg
, MEMCG_SWAP
, -nr_pages
);
7319 mem_cgroup_id_put_many(memcg
, nr_pages
);
7324 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup
*memcg
)
7326 long nr_swap_pages
= get_nr_swap_pages();
7328 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7329 return nr_swap_pages
;
7330 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
))
7331 nr_swap_pages
= min_t(long, nr_swap_pages
,
7332 READ_ONCE(memcg
->swap
.max
) -
7333 page_counter_read(&memcg
->swap
));
7334 return nr_swap_pages
;
7337 bool mem_cgroup_swap_full(struct page
*page
)
7339 struct mem_cgroup
*memcg
;
7341 VM_BUG_ON_PAGE(!PageLocked(page
), page
);
7345 if (cgroup_memory_noswap
|| !cgroup_subsys_on_dfl(memory_cgrp_subsys
))
7348 memcg
= page_memcg(page
);
7352 for (; memcg
!= root_mem_cgroup
; memcg
= parent_mem_cgroup(memcg
)) {
7353 unsigned long usage
= page_counter_read(&memcg
->swap
);
7355 if (usage
* 2 >= READ_ONCE(memcg
->swap
.high
) ||
7356 usage
* 2 >= READ_ONCE(memcg
->swap
.max
))
7363 static int __init
setup_swap_account(char *s
)
7365 if (!strcmp(s
, "1"))
7366 cgroup_memory_noswap
= false;
7367 else if (!strcmp(s
, "0"))
7368 cgroup_memory_noswap
= true;
7371 __setup("swapaccount=", setup_swap_account
);
7373 static u64
swap_current_read(struct cgroup_subsys_state
*css
,
7376 struct mem_cgroup
*memcg
= mem_cgroup_from_css(css
);
7378 return (u64
)page_counter_read(&memcg
->swap
) * PAGE_SIZE
;
7381 static int swap_high_show(struct seq_file
*m
, void *v
)
7383 return seq_puts_memcg_tunable(m
,
7384 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.high
));
7387 static ssize_t
swap_high_write(struct kernfs_open_file
*of
,
7388 char *buf
, size_t nbytes
, loff_t off
)
7390 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7394 buf
= strstrip(buf
);
7395 err
= page_counter_memparse(buf
, "max", &high
);
7399 page_counter_set_high(&memcg
->swap
, high
);
7404 static int swap_max_show(struct seq_file
*m
, void *v
)
7406 return seq_puts_memcg_tunable(m
,
7407 READ_ONCE(mem_cgroup_from_seq(m
)->swap
.max
));
7410 static ssize_t
swap_max_write(struct kernfs_open_file
*of
,
7411 char *buf
, size_t nbytes
, loff_t off
)
7413 struct mem_cgroup
*memcg
= mem_cgroup_from_css(of_css(of
));
7417 buf
= strstrip(buf
);
7418 err
= page_counter_memparse(buf
, "max", &max
);
7422 xchg(&memcg
->swap
.max
, max
);
7427 static int swap_events_show(struct seq_file
*m
, void *v
)
7429 struct mem_cgroup
*memcg
= mem_cgroup_from_seq(m
);
7431 seq_printf(m
, "high %lu\n",
7432 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_HIGH
]));
7433 seq_printf(m
, "max %lu\n",
7434 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_MAX
]));
7435 seq_printf(m
, "fail %lu\n",
7436 atomic_long_read(&memcg
->memory_events
[MEMCG_SWAP_FAIL
]));
7441 static struct cftype swap_files
[] = {
7443 .name
= "swap.current",
7444 .flags
= CFTYPE_NOT_ON_ROOT
,
7445 .read_u64
= swap_current_read
,
7448 .name
= "swap.high",
7449 .flags
= CFTYPE_NOT_ON_ROOT
,
7450 .seq_show
= swap_high_show
,
7451 .write
= swap_high_write
,
7455 .flags
= CFTYPE_NOT_ON_ROOT
,
7456 .seq_show
= swap_max_show
,
7457 .write
= swap_max_write
,
7460 .name
= "swap.events",
7461 .flags
= CFTYPE_NOT_ON_ROOT
,
7462 .file_offset
= offsetof(struct mem_cgroup
, swap_events_file
),
7463 .seq_show
= swap_events_show
,
7468 static struct cftype memsw_files
[] = {
7470 .name
= "memsw.usage_in_bytes",
7471 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_USAGE
),
7472 .read_u64
= mem_cgroup_read_u64
,
7475 .name
= "memsw.max_usage_in_bytes",
7476 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_MAX_USAGE
),
7477 .write
= mem_cgroup_reset
,
7478 .read_u64
= mem_cgroup_read_u64
,
7481 .name
= "memsw.limit_in_bytes",
7482 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_LIMIT
),
7483 .write
= mem_cgroup_write
,
7484 .read_u64
= mem_cgroup_read_u64
,
7487 .name
= "memsw.failcnt",
7488 .private = MEMFILE_PRIVATE(_MEMSWAP
, RES_FAILCNT
),
7489 .write
= mem_cgroup_reset
,
7490 .read_u64
= mem_cgroup_read_u64
,
7492 { }, /* terminate */
7496 * If mem_cgroup_swap_init() is implemented as a subsys_initcall()
7497 * instead of a core_initcall(), this could mean cgroup_memory_noswap still
7498 * remains set to false even when memcg is disabled via "cgroup_disable=memory"
7499 * boot parameter. This may result in premature OOPS inside
7500 * mem_cgroup_get_nr_swap_pages() function in corner cases.
7502 static int __init
mem_cgroup_swap_init(void)
7504 /* No memory control -> no swap control */
7505 if (mem_cgroup_disabled())
7506 cgroup_memory_noswap
= true;
7508 if (cgroup_memory_noswap
)
7511 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys
, swap_files
));
7512 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys
, memsw_files
));
7516 core_initcall(mem_cgroup_swap_init
);
7518 #endif /* CONFIG_MEMCG_SWAP */