1 /* memcontrol.c - Memory Controller
3 * Copyright IBM Corporation, 2007
4 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
6 * Copyright 2007 OpenVZ SWsoft Inc
7 * Author: Pavel Emelianov <xemul@openvz.org>
10 * Copyright (C) 2009 Nokia Corporation
11 * Author: Kirill A. Shutemov
13 * Kernel Memory Controller
14 * Copyright (C) 2012 Parallels Inc. and Google Inc.
15 * Authors: Glauber Costa and Suleiman Souhlal
18 * Charge lifetime sanitation
19 * Lockless page tracking & accounting
20 * Unified hierarchy configuration model
21 * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
23 * This program is free software; you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License as published by
25 * the Free Software Foundation; either version 2 of the License, or
26 * (at your option) any later version.
28 * This program is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 * GNU General Public License for more details.
34 #include <linux/page_counter.h>
35 #include <linux/memcontrol.h>
36 #include <linux/cgroup.h>
38 #include <linux/hugetlb.h>
39 #include <linux/pagemap.h>
40 #include <linux/smp.h>
41 #include <linux/page-flags.h>
42 #include <linux/backing-dev.h>
43 #include <linux/bit_spinlock.h>
44 #include <linux/rcupdate.h>
45 #include <linux/limits.h>
46 #include <linux/export.h>
47 #include <linux/mutex.h>
48 #include <linux/rbtree.h>
49 #include <linux/slab.h>
50 #include <linux/swap.h>
51 #include <linux/swapops.h>
52 #include <linux/spinlock.h>
53 #include <linux/eventfd.h>
54 #include <linux/poll.h>
55 #include <linux/sort.h>
57 #include <linux/seq_file.h>
58 #include <linux/vmpressure.h>
59 #include <linux/mm_inline.h>
60 #include <linux/swap_cgroup.h>
61 #include <linux/cpu.h>
62 #include <linux/oom.h>
63 #include <linux/lockdep.h>
64 #include <linux/file.h>
65 #include <linux/tracehook.h>
71 #include <asm/uaccess.h>
73 #include <trace/events/vmscan.h>
75 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
76 EXPORT_SYMBOL(memory_cgrp_subsys);
78 struct mem_cgroup *root_mem_cgroup __read_mostly;
80 #define MEM_CGROUP_RECLAIM_RETRIES 5
82 /* Socket memory accounting disabled? */
83 static bool cgroup_memory_nosocket;
85 /* Kernel memory accounting disabled? */
86 static bool cgroup_memory_nokmem;
88 /* Whether the swap controller is active */
89 #ifdef CONFIG_MEMCG_SWAP
90 int do_swap_account __read_mostly;
92 #define do_swap_account 0
95 /* Whether legacy memory+swap accounting is active */
96 static bool do_memsw_account(void)
98 return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;
101 static const char * const mem_cgroup_stat_names[] = {
111 static const char * const mem_cgroup_events_names[] = {
118 static const char * const mem_cgroup_lru_names[] = {
126 #define THRESHOLDS_EVENTS_TARGET 128
127 #define SOFTLIMIT_EVENTS_TARGET 1024
128 #define NUMAINFO_EVENTS_TARGET 1024
131 * Cgroups above their limits are maintained in a RB-Tree, independent of
132 * their hierarchy representation
135 struct mem_cgroup_tree_per_node {
136 struct rb_root rb_root;
140 struct mem_cgroup_tree {
141 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
144 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
147 struct mem_cgroup_eventfd_list {
148 struct list_head list;
149 struct eventfd_ctx *eventfd;
153 * cgroup_event represents events which userspace want to receive.
155 struct mem_cgroup_event {
157 * memcg which the event belongs to.
159 struct mem_cgroup *memcg;
161 * eventfd to signal userspace about the event.
163 struct eventfd_ctx *eventfd;
165 * Each of these stored in a list by the cgroup.
167 struct list_head list;
169 * register_event() callback will be used to add new userspace
170 * waiter for changes related to this event. Use eventfd_signal()
171 * on eventfd to send notification to userspace.
173 int (*register_event)(struct mem_cgroup *memcg,
174 struct eventfd_ctx *eventfd, const char *args);
176 * unregister_event() callback will be called when userspace closes
177 * the eventfd or on cgroup removing. This callback must be set,
178 * if you want provide notification functionality.
180 void (*unregister_event)(struct mem_cgroup *memcg,
181 struct eventfd_ctx *eventfd);
183 * All fields below needed to unregister event when
184 * userspace closes eventfd.
187 wait_queue_head_t *wqh;
189 struct work_struct remove;
192 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
193 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
195 /* Stuffs for move charges at task migration. */
197 * Types of charges to be moved.
199 #define MOVE_ANON 0x1U
200 #define MOVE_FILE 0x2U
201 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
203 /* "mc" and its members are protected by cgroup_mutex */
204 static struct move_charge_struct {
205 spinlock_t lock; /* for from, to */
206 struct mm_struct *mm;
207 struct mem_cgroup *from;
208 struct mem_cgroup *to;
210 unsigned long precharge;
211 unsigned long moved_charge;
212 unsigned long moved_swap;
213 struct task_struct *moving_task; /* a task moving charges */
214 wait_queue_head_t waitq; /* a waitq for other context */
216 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
217 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
221 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
222 * limit reclaim to prevent infinite loops, if they ever occur.
224 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
225 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
228 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
229 MEM_CGROUP_CHARGE_TYPE_ANON,
230 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
231 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
235 /* for encoding cft->private value on file */
244 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
245 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
246 #define MEMFILE_ATTR(val) ((val) & 0xffff)
247 /* Used for OOM nofiier */
248 #define OOM_CONTROL (0)
250 /* Some nice accessors for the vmpressure. */
251 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
254 memcg = root_mem_cgroup;
255 return &memcg->vmpressure;
258 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
260 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
263 static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
265 return (memcg == root_mem_cgroup);
270 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
271 * The main reason for not using cgroup id for this:
272 * this works better in sparse environments, where we have a lot of memcgs,
273 * but only a few kmem-limited. Or also, if we have, for instance, 200
274 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
275 * 200 entry array for that.
277 * The current size of the caches array is stored in memcg_nr_cache_ids. It
278 * will double each time we have to increase it.
280 static DEFINE_IDA(memcg_cache_ida);
281 int memcg_nr_cache_ids;
283 /* Protects memcg_nr_cache_ids */
284 static DECLARE_RWSEM(memcg_cache_ids_sem);
286 void memcg_get_cache_ids(void)
288 down_read(&memcg_cache_ids_sem);
291 void memcg_put_cache_ids(void)
293 up_read(&memcg_cache_ids_sem);
297 * MIN_SIZE is different than 1, because we would like to avoid going through
298 * the alloc/free process all the time. In a small machine, 4 kmem-limited
299 * cgroups is a reasonable guess. In the future, it could be a parameter or
300 * tunable, but that is strictly not necessary.
302 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
303 * this constant directly from cgroup, but it is understandable that this is
304 * better kept as an internal representation in cgroup.c. In any case, the
305 * cgrp_id space is not getting any smaller, and we don't have to necessarily
306 * increase ours as well if it increases.
308 #define MEMCG_CACHES_MIN_SIZE 4
309 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
312 * A lot of the calls to the cache allocation functions are expected to be
313 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
314 * conditional to this static branch, we'll have to allow modules that does
315 * kmem_cache_alloc and the such to see this symbol as well
317 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
318 EXPORT_SYMBOL(memcg_kmem_enabled_key);
320 #endif /* !CONFIG_SLOB */
323 * mem_cgroup_css_from_page - css of the memcg associated with a page
324 * @page: page of interest
326 * If memcg is bound to the default hierarchy, css of the memcg associated
327 * with @page is returned. The returned css remains associated with @page
328 * until it is released.
330 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
333 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
335 struct mem_cgroup *memcg;
337 memcg = page->mem_cgroup;
339 if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
340 memcg = root_mem_cgroup;
346 * page_cgroup_ino - return inode number of the memcg a page is charged to
349 * Look up the closest online ancestor of the memory cgroup @page is charged to
350 * and return its inode number or 0 if @page is not charged to any cgroup. It
351 * is safe to call this function without holding a reference to @page.
353 * Note, this function is inherently racy, because there is nothing to prevent
354 * the cgroup inode from getting torn down and potentially reallocated a moment
355 * after page_cgroup_ino() returns, so it only should be used by callers that
356 * do not care (such as procfs interfaces).
358 ino_t page_cgroup_ino(struct page *page)
360 struct mem_cgroup *memcg;
361 unsigned long ino = 0;
364 memcg = READ_ONCE(page->mem_cgroup);
365 while (memcg && !(memcg->css.flags & CSS_ONLINE))
366 memcg = parent_mem_cgroup(memcg);
368 ino = cgroup_ino(memcg->css.cgroup);
373 static struct mem_cgroup_per_node *
374 mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
376 int nid = page_to_nid(page);
378 return memcg->nodeinfo[nid];
381 static struct mem_cgroup_tree_per_node *
382 soft_limit_tree_node(int nid)
384 return soft_limit_tree.rb_tree_per_node[nid];
387 static struct mem_cgroup_tree_per_node *
388 soft_limit_tree_from_page(struct page *page)
390 int nid = page_to_nid(page);
392 return soft_limit_tree.rb_tree_per_node[nid];
395 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
396 struct mem_cgroup_tree_per_node *mctz,
397 unsigned long new_usage_in_excess)
399 struct rb_node **p = &mctz->rb_root.rb_node;
400 struct rb_node *parent = NULL;
401 struct mem_cgroup_per_node *mz_node;
406 mz->usage_in_excess = new_usage_in_excess;
407 if (!mz->usage_in_excess)
411 mz_node = rb_entry(parent, struct mem_cgroup_per_node,
413 if (mz->usage_in_excess < mz_node->usage_in_excess)
416 * We can't avoid mem cgroups that are over their soft
417 * limit by the same amount
419 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
422 rb_link_node(&mz->tree_node, parent, p);
423 rb_insert_color(&mz->tree_node, &mctz->rb_root);
427 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
428 struct mem_cgroup_tree_per_node *mctz)
432 rb_erase(&mz->tree_node, &mctz->rb_root);
436 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
437 struct mem_cgroup_tree_per_node *mctz)
441 spin_lock_irqsave(&mctz->lock, flags);
442 __mem_cgroup_remove_exceeded(mz, mctz);
443 spin_unlock_irqrestore(&mctz->lock, flags);
446 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
448 unsigned long nr_pages = page_counter_read(&memcg->memory);
449 unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
450 unsigned long excess = 0;
452 if (nr_pages > soft_limit)
453 excess = nr_pages - soft_limit;
458 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
460 unsigned long excess;
461 struct mem_cgroup_per_node *mz;
462 struct mem_cgroup_tree_per_node *mctz;
464 mctz = soft_limit_tree_from_page(page);
466 * Necessary to update all ancestors when hierarchy is used.
467 * because their event counter is not touched.
469 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
470 mz = mem_cgroup_page_nodeinfo(memcg, page);
471 excess = soft_limit_excess(memcg);
473 * We have to update the tree if mz is on RB-tree or
474 * mem is over its softlimit.
476 if (excess || mz->on_tree) {
479 spin_lock_irqsave(&mctz->lock, flags);
480 /* if on-tree, remove it */
482 __mem_cgroup_remove_exceeded(mz, mctz);
484 * Insert again. mz->usage_in_excess will be updated.
485 * If excess is 0, no tree ops.
487 __mem_cgroup_insert_exceeded(mz, mctz, excess);
488 spin_unlock_irqrestore(&mctz->lock, flags);
493 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
495 struct mem_cgroup_tree_per_node *mctz;
496 struct mem_cgroup_per_node *mz;
500 mz = mem_cgroup_nodeinfo(memcg, nid);
501 mctz = soft_limit_tree_node(nid);
502 mem_cgroup_remove_exceeded(mz, mctz);
506 static struct mem_cgroup_per_node *
507 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
509 struct rb_node *rightmost = NULL;
510 struct mem_cgroup_per_node *mz;
514 rightmost = rb_last(&mctz->rb_root);
516 goto done; /* Nothing to reclaim from */
518 mz = rb_entry(rightmost, struct mem_cgroup_per_node, tree_node);
520 * Remove the node now but someone else can add it back,
521 * we will to add it back at the end of reclaim to its correct
522 * position in the tree.
524 __mem_cgroup_remove_exceeded(mz, mctz);
525 if (!soft_limit_excess(mz->memcg) ||
526 !css_tryget_online(&mz->memcg->css))
532 static struct mem_cgroup_per_node *
533 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
535 struct mem_cgroup_per_node *mz;
537 spin_lock_irq(&mctz->lock);
538 mz = __mem_cgroup_largest_soft_limit_node(mctz);
539 spin_unlock_irq(&mctz->lock);
544 * Return page count for single (non recursive) @memcg.
546 * Implementation Note: reading percpu statistics for memcg.
548 * Both of vmstat[] and percpu_counter has threshold and do periodic
549 * synchronization to implement "quick" read. There are trade-off between
550 * reading cost and precision of value. Then, we may have a chance to implement
551 * a periodic synchronization of counter in memcg's counter.
553 * But this _read() function is used for user interface now. The user accounts
554 * memory usage by memory cgroup and he _always_ requires exact value because
555 * he accounts memory. Even if we provide quick-and-fuzzy read, we always
556 * have to visit all online cpus and make sum. So, for now, unnecessary
557 * synchronization is not implemented. (just implemented for cpu hotplug)
559 * If there are kernel internal actions which can make use of some not-exact
560 * value, and reading all cpu value can be performance bottleneck in some
561 * common workload, threshold and synchronization as vmstat[] should be
565 mem_cgroup_read_stat(struct mem_cgroup *memcg, enum mem_cgroup_stat_index idx)
570 /* Per-cpu values can be negative, use a signed accumulator */
571 for_each_possible_cpu(cpu)
572 val += per_cpu(memcg->stat->count[idx], cpu);
574 * Summing races with updates, so val may be negative. Avoid exposing
575 * transient negative values.
582 static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
583 enum mem_cgroup_events_index idx)
585 unsigned long val = 0;
588 for_each_possible_cpu(cpu)
589 val += per_cpu(memcg->stat->events[idx], cpu);
593 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
595 bool compound, int nr_pages)
598 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
599 * counted as CACHE even if it's on ANON LRU.
602 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS],
605 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_CACHE],
609 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
610 __this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
614 /* pagein of a big page is an event. So, ignore page size */
616 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
618 __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
619 nr_pages = -nr_pages; /* for event */
622 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
625 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
626 int nid, unsigned int lru_mask)
628 unsigned long nr = 0;
629 struct mem_cgroup_per_node *mz;
632 VM_BUG_ON((unsigned)nid >= nr_node_ids);
635 if (!(BIT(lru) & lru_mask))
637 mz = mem_cgroup_nodeinfo(memcg, nid);
638 nr += mz->lru_size[lru];
643 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
644 unsigned int lru_mask)
646 unsigned long nr = 0;
649 for_each_node_state(nid, N_MEMORY)
650 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
654 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
655 enum mem_cgroup_events_target target)
657 unsigned long val, next;
659 val = __this_cpu_read(memcg->stat->nr_page_events);
660 next = __this_cpu_read(memcg->stat->targets[target]);
661 /* from time_after() in jiffies.h */
662 if ((long)next - (long)val < 0) {
664 case MEM_CGROUP_TARGET_THRESH:
665 next = val + THRESHOLDS_EVENTS_TARGET;
667 case MEM_CGROUP_TARGET_SOFTLIMIT:
668 next = val + SOFTLIMIT_EVENTS_TARGET;
670 case MEM_CGROUP_TARGET_NUMAINFO:
671 next = val + NUMAINFO_EVENTS_TARGET;
676 __this_cpu_write(memcg->stat->targets[target], next);
683 * Check events in order.
686 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
688 /* threshold event is triggered in finer grain than soft limit */
689 if (unlikely(mem_cgroup_event_ratelimit(memcg,
690 MEM_CGROUP_TARGET_THRESH))) {
692 bool do_numainfo __maybe_unused;
694 do_softlimit = mem_cgroup_event_ratelimit(memcg,
695 MEM_CGROUP_TARGET_SOFTLIMIT);
697 do_numainfo = mem_cgroup_event_ratelimit(memcg,
698 MEM_CGROUP_TARGET_NUMAINFO);
700 mem_cgroup_threshold(memcg);
701 if (unlikely(do_softlimit))
702 mem_cgroup_update_tree(memcg, page);
704 if (unlikely(do_numainfo))
705 atomic_inc(&memcg->numainfo_events);
710 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
713 * mm_update_next_owner() may clear mm->owner to NULL
714 * if it races with swapoff, page migration, etc.
715 * So this can be called with p == NULL.
720 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
722 EXPORT_SYMBOL(mem_cgroup_from_task);
724 static struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
726 struct mem_cgroup *memcg = NULL;
731 * Page cache insertions can happen withou an
732 * actual mm context, e.g. during disk probing
733 * on boot, loopback IO, acct() writes etc.
736 memcg = root_mem_cgroup;
738 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
739 if (unlikely(!memcg))
740 memcg = root_mem_cgroup;
742 } while (!css_tryget_online(&memcg->css));
748 * mem_cgroup_iter - iterate over memory cgroup hierarchy
749 * @root: hierarchy root
750 * @prev: previously returned memcg, NULL on first invocation
751 * @reclaim: cookie for shared reclaim walks, NULL for full walks
753 * Returns references to children of the hierarchy below @root, or
754 * @root itself, or %NULL after a full round-trip.
756 * Caller must pass the return value in @prev on subsequent
757 * invocations for reference counting, or use mem_cgroup_iter_break()
758 * to cancel a hierarchy walk before the round-trip is complete.
760 * Reclaimers can specify a zone and a priority level in @reclaim to
761 * divide up the memcgs in the hierarchy among all concurrent
762 * reclaimers operating on the same zone and priority.
764 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
765 struct mem_cgroup *prev,
766 struct mem_cgroup_reclaim_cookie *reclaim)
768 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
769 struct cgroup_subsys_state *css = NULL;
770 struct mem_cgroup *memcg = NULL;
771 struct mem_cgroup *pos = NULL;
773 if (mem_cgroup_disabled())
777 root = root_mem_cgroup;
779 if (prev && !reclaim)
782 if (!root->use_hierarchy && root != root_mem_cgroup) {
791 struct mem_cgroup_per_node *mz;
793 mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
794 iter = &mz->iter[reclaim->priority];
796 if (prev && reclaim->generation != iter->generation)
800 pos = READ_ONCE(iter->position);
801 if (!pos || css_tryget(&pos->css))
804 * css reference reached zero, so iter->position will
805 * be cleared by ->css_released. However, we should not
806 * rely on this happening soon, because ->css_released
807 * is called from a work queue, and by busy-waiting we
808 * might block it. So we clear iter->position right
811 (void)cmpxchg(&iter->position, pos, NULL);
819 css = css_next_descendant_pre(css, &root->css);
822 * Reclaimers share the hierarchy walk, and a
823 * new one might jump in right at the end of
824 * the hierarchy - make sure they see at least
825 * one group and restart from the beginning.
833 * Verify the css and acquire a reference. The root
834 * is provided by the caller, so we know it's alive
835 * and kicking, and don't take an extra reference.
837 memcg = mem_cgroup_from_css(css);
839 if (css == &root->css)
850 * The position could have already been updated by a competing
851 * thread, so check that the value hasn't changed since we read
852 * it to avoid reclaiming from the same cgroup twice.
854 (void)cmpxchg(&iter->position, pos, memcg);
862 reclaim->generation = iter->generation;
868 if (prev && prev != root)
875 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
876 * @root: hierarchy root
877 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
879 void mem_cgroup_iter_break(struct mem_cgroup *root,
880 struct mem_cgroup *prev)
883 root = root_mem_cgroup;
884 if (prev && prev != root)
888 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
890 struct mem_cgroup *memcg = dead_memcg;
891 struct mem_cgroup_reclaim_iter *iter;
892 struct mem_cgroup_per_node *mz;
896 while ((memcg = parent_mem_cgroup(memcg))) {
898 mz = mem_cgroup_nodeinfo(memcg, nid);
899 for (i = 0; i <= DEF_PRIORITY; i++) {
901 cmpxchg(&iter->position,
909 * Iteration constructs for visiting all cgroups (under a tree). If
910 * loops are exited prematurely (break), mem_cgroup_iter_break() must
911 * be used for reference counting.
913 #define for_each_mem_cgroup_tree(iter, root) \
914 for (iter = mem_cgroup_iter(root, NULL, NULL); \
916 iter = mem_cgroup_iter(root, iter, NULL))
918 #define for_each_mem_cgroup(iter) \
919 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
921 iter = mem_cgroup_iter(NULL, iter, NULL))
924 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
925 * @memcg: hierarchy root
926 * @fn: function to call for each task
927 * @arg: argument passed to @fn
929 * This function iterates over tasks attached to @memcg or to any of its
930 * descendants and calls @fn for each task. If @fn returns a non-zero
931 * value, the function breaks the iteration loop and returns the value.
932 * Otherwise, it will iterate over all tasks and return 0.
934 * This function must not be called for the root memory cgroup.
936 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
937 int (*fn)(struct task_struct *, void *), void *arg)
939 struct mem_cgroup *iter;
942 BUG_ON(memcg == root_mem_cgroup);
944 for_each_mem_cgroup_tree(iter, memcg) {
945 struct css_task_iter it;
946 struct task_struct *task;
948 css_task_iter_start(&iter->css, &it);
949 while (!ret && (task = css_task_iter_next(&it)))
951 css_task_iter_end(&it);
953 mem_cgroup_iter_break(memcg, iter);
961 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
963 * @zone: zone of the page
965 * This function is only safe when following the LRU page isolation
966 * and putback protocol: the LRU lock must be held, and the page must
967 * either be PageLRU() or the caller must have isolated/allocated it.
969 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
971 struct mem_cgroup_per_node *mz;
972 struct mem_cgroup *memcg;
973 struct lruvec *lruvec;
975 if (mem_cgroup_disabled()) {
976 lruvec = &pgdat->lruvec;
980 memcg = page->mem_cgroup;
982 * Swapcache readahead pages are added to the LRU - and
983 * possibly migrated - before they are charged.
986 memcg = root_mem_cgroup;
988 mz = mem_cgroup_page_nodeinfo(memcg, page);
989 lruvec = &mz->lruvec;
992 * Since a node can be onlined after the mem_cgroup was created,
993 * we have to be prepared to initialize lruvec->zone here;
994 * and if offlined then reonlined, we need to reinitialize it.
996 if (unlikely(lruvec->pgdat != pgdat))
997 lruvec->pgdat = pgdat;
1002 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1003 * @lruvec: mem_cgroup per zone lru vector
1004 * @lru: index of lru list the page is sitting on
1005 * @nr_pages: positive when adding or negative when removing
1007 * This function must be called under lru_lock, just before a page is added
1008 * to or just after a page is removed from an lru list (that ordering being
1009 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1011 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1014 struct mem_cgroup_per_node *mz;
1015 unsigned long *lru_size;
1019 if (mem_cgroup_disabled())
1022 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1023 lru_size = mz->lru_size + lru;
1024 empty = list_empty(lruvec->lists + lru);
1027 *lru_size += nr_pages;
1030 if (WARN_ONCE(size < 0 || empty != !size,
1031 "%s(%p, %d, %d): lru_size %ld but %sempty\n",
1032 __func__, lruvec, lru, nr_pages, size, empty ? "" : "not ")) {
1038 *lru_size += nr_pages;
1041 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
1043 struct mem_cgroup *task_memcg;
1044 struct task_struct *p;
1047 p = find_lock_task_mm(task);
1049 task_memcg = get_mem_cgroup_from_mm(p->mm);
1053 * All threads may have already detached their mm's, but the oom
1054 * killer still needs to detect if they have already been oom
1055 * killed to prevent needlessly killing additional tasks.
1058 task_memcg = mem_cgroup_from_task(task);
1059 css_get(&task_memcg->css);
1062 ret = mem_cgroup_is_descendant(task_memcg, memcg);
1063 css_put(&task_memcg->css);
1068 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1069 * @memcg: the memory cgroup
1071 * Returns the maximum amount of memory @mem can be charged with, in
1074 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1076 unsigned long margin = 0;
1077 unsigned long count;
1078 unsigned long limit;
1080 count = page_counter_read(&memcg->memory);
1081 limit = READ_ONCE(memcg->memory.limit);
1083 margin = limit - count;
1085 if (do_memsw_account()) {
1086 count = page_counter_read(&memcg->memsw);
1087 limit = READ_ONCE(memcg->memsw.limit);
1089 margin = min(margin, limit - count);
1098 * A routine for checking "mem" is under move_account() or not.
1100 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1101 * moving cgroups. This is for waiting at high-memory pressure
1104 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1106 struct mem_cgroup *from;
1107 struct mem_cgroup *to;
1110 * Unlike task_move routines, we access mc.to, mc.from not under
1111 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1113 spin_lock(&mc.lock);
1119 ret = mem_cgroup_is_descendant(from, memcg) ||
1120 mem_cgroup_is_descendant(to, memcg);
1122 spin_unlock(&mc.lock);
1126 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1128 if (mc.moving_task && current != mc.moving_task) {
1129 if (mem_cgroup_under_move(memcg)) {
1131 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1132 /* moving charge context might have finished. */
1135 finish_wait(&mc.waitq, &wait);
1142 #define K(x) ((x) << (PAGE_SHIFT-10))
1144 * mem_cgroup_print_oom_info: Print OOM information relevant to memory controller.
1145 * @memcg: The memory cgroup that went over limit
1146 * @p: Task that is going to be killed
1148 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1151 void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
1153 struct mem_cgroup *iter;
1159 pr_info("Task in ");
1160 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1161 pr_cont(" killed as a result of limit of ");
1163 pr_info("Memory limit reached of cgroup ");
1166 pr_cont_cgroup_path(memcg->css.cgroup);
1171 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1172 K((u64)page_counter_read(&memcg->memory)),
1173 K((u64)memcg->memory.limit), memcg->memory.failcnt);
1174 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1175 K((u64)page_counter_read(&memcg->memsw)),
1176 K((u64)memcg->memsw.limit), memcg->memsw.failcnt);
1177 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1178 K((u64)page_counter_read(&memcg->kmem)),
1179 K((u64)memcg->kmem.limit), memcg->kmem.failcnt);
1181 for_each_mem_cgroup_tree(iter, memcg) {
1182 pr_info("Memory cgroup stats for ");
1183 pr_cont_cgroup_path(iter->css.cgroup);
1186 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
1187 if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)
1189 pr_cont(" %s:%luKB", mem_cgroup_stat_names[i],
1190 K(mem_cgroup_read_stat(iter, i)));
1193 for (i = 0; i < NR_LRU_LISTS; i++)
1194 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1195 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1202 * This function returns the number of memcg under hierarchy tree. Returns
1203 * 1(self count) if no children.
1205 static int mem_cgroup_count_children(struct mem_cgroup *memcg)
1208 struct mem_cgroup *iter;
1210 for_each_mem_cgroup_tree(iter, memcg)
1216 * Return the memory (and swap, if configured) limit for a memcg.
1218 unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
1220 unsigned long limit;
1222 limit = memcg->memory.limit;
1223 if (mem_cgroup_swappiness(memcg)) {
1224 unsigned long memsw_limit;
1225 unsigned long swap_limit;
1227 memsw_limit = memcg->memsw.limit;
1228 swap_limit = memcg->swap.limit;
1229 swap_limit = min(swap_limit, (unsigned long)total_swap_pages);
1230 limit = min(limit + swap_limit, memsw_limit);
1235 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1238 struct oom_control oc = {
1242 .gfp_mask = gfp_mask,
1247 mutex_lock(&oom_lock);
1248 ret = out_of_memory(&oc);
1249 mutex_unlock(&oom_lock);
1253 #if MAX_NUMNODES > 1
1256 * test_mem_cgroup_node_reclaimable
1257 * @memcg: the target memcg
1258 * @nid: the node ID to be checked.
1259 * @noswap : specify true here if the user wants flle only information.
1261 * This function returns whether the specified memcg contains any
1262 * reclaimable pages on a node. Returns true if there are any reclaimable
1263 * pages in the node.
1265 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1266 int nid, bool noswap)
1268 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1270 if (noswap || !total_swap_pages)
1272 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1279 * Always updating the nodemask is not very good - even if we have an empty
1280 * list or the wrong list here, we can start from some node and traverse all
1281 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1284 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1288 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1289 * pagein/pageout changes since the last update.
1291 if (!atomic_read(&memcg->numainfo_events))
1293 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1296 /* make a nodemask where this memcg uses memory from */
1297 memcg->scan_nodes = node_states[N_MEMORY];
1299 for_each_node_mask(nid, node_states[N_MEMORY]) {
1301 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1302 node_clear(nid, memcg->scan_nodes);
1305 atomic_set(&memcg->numainfo_events, 0);
1306 atomic_set(&memcg->numainfo_updating, 0);
1310 * Selecting a node where we start reclaim from. Because what we need is just
1311 * reducing usage counter, start from anywhere is O,K. Considering
1312 * memory reclaim from current node, there are pros. and cons.
1314 * Freeing memory from current node means freeing memory from a node which
1315 * we'll use or we've used. So, it may make LRU bad. And if several threads
1316 * hit limits, it will see a contention on a node. But freeing from remote
1317 * node means more costs for memory reclaim because of memory latency.
1319 * Now, we use round-robin. Better algorithm is welcomed.
1321 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1325 mem_cgroup_may_update_nodemask(memcg);
1326 node = memcg->last_scanned_node;
1328 node = next_node_in(node, memcg->scan_nodes);
1330 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1331 * last time it really checked all the LRUs due to rate limiting.
1332 * Fallback to the current node in that case for simplicity.
1334 if (unlikely(node == MAX_NUMNODES))
1335 node = numa_node_id();
1337 memcg->last_scanned_node = node;
1341 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1347 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1350 unsigned long *total_scanned)
1352 struct mem_cgroup *victim = NULL;
1355 unsigned long excess;
1356 unsigned long nr_scanned;
1357 struct mem_cgroup_reclaim_cookie reclaim = {
1362 excess = soft_limit_excess(root_memcg);
1365 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1370 * If we have not been able to reclaim
1371 * anything, it might because there are
1372 * no reclaimable pages under this hierarchy
1377 * We want to do more targeted reclaim.
1378 * excess >> 2 is not to excessive so as to
1379 * reclaim too much, nor too less that we keep
1380 * coming back to reclaim from this cgroup
1382 if (total >= (excess >> 2) ||
1383 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1388 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1389 pgdat, &nr_scanned);
1390 *total_scanned += nr_scanned;
1391 if (!soft_limit_excess(root_memcg))
1394 mem_cgroup_iter_break(root_memcg, victim);
1398 #ifdef CONFIG_LOCKDEP
1399 static struct lockdep_map memcg_oom_lock_dep_map = {
1400 .name = "memcg_oom_lock",
1404 static DEFINE_SPINLOCK(memcg_oom_lock);
1407 * Check OOM-Killer is already running under our hierarchy.
1408 * If someone is running, return false.
1410 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1412 struct mem_cgroup *iter, *failed = NULL;
1414 spin_lock(&memcg_oom_lock);
1416 for_each_mem_cgroup_tree(iter, memcg) {
1417 if (iter->oom_lock) {
1419 * this subtree of our hierarchy is already locked
1420 * so we cannot give a lock.
1423 mem_cgroup_iter_break(memcg, iter);
1426 iter->oom_lock = true;
1431 * OK, we failed to lock the whole subtree so we have
1432 * to clean up what we set up to the failing subtree
1434 for_each_mem_cgroup_tree(iter, memcg) {
1435 if (iter == failed) {
1436 mem_cgroup_iter_break(memcg, iter);
1439 iter->oom_lock = false;
1442 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1444 spin_unlock(&memcg_oom_lock);
1449 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1451 struct mem_cgroup *iter;
1453 spin_lock(&memcg_oom_lock);
1454 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
1455 for_each_mem_cgroup_tree(iter, memcg)
1456 iter->oom_lock = false;
1457 spin_unlock(&memcg_oom_lock);
1460 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1462 struct mem_cgroup *iter;
1464 spin_lock(&memcg_oom_lock);
1465 for_each_mem_cgroup_tree(iter, memcg)
1467 spin_unlock(&memcg_oom_lock);
1470 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1472 struct mem_cgroup *iter;
1475 * When a new child is created while the hierarchy is under oom,
1476 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1478 spin_lock(&memcg_oom_lock);
1479 for_each_mem_cgroup_tree(iter, memcg)
1480 if (iter->under_oom > 0)
1482 spin_unlock(&memcg_oom_lock);
1485 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1487 struct oom_wait_info {
1488 struct mem_cgroup *memcg;
1492 static int memcg_oom_wake_function(wait_queue_t *wait,
1493 unsigned mode, int sync, void *arg)
1495 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1496 struct mem_cgroup *oom_wait_memcg;
1497 struct oom_wait_info *oom_wait_info;
1499 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1500 oom_wait_memcg = oom_wait_info->memcg;
1502 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1503 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1505 return autoremove_wake_function(wait, mode, sync, arg);
1508 static void memcg_oom_recover(struct mem_cgroup *memcg)
1511 * For the following lockless ->under_oom test, the only required
1512 * guarantee is that it must see the state asserted by an OOM when
1513 * this function is called as a result of userland actions
1514 * triggered by the notification of the OOM. This is trivially
1515 * achieved by invoking mem_cgroup_mark_under_oom() before
1516 * triggering notification.
1518 if (memcg && memcg->under_oom)
1519 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1522 static void mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1524 if (!current->memcg_may_oom)
1527 * We are in the middle of the charge context here, so we
1528 * don't want to block when potentially sitting on a callstack
1529 * that holds all kinds of filesystem and mm locks.
1531 * Also, the caller may handle a failed allocation gracefully
1532 * (like optional page cache readahead) and so an OOM killer
1533 * invocation might not even be necessary.
1535 * That's why we don't do anything here except remember the
1536 * OOM context and then deal with it at the end of the page
1537 * fault when the stack is unwound, the locks are released,
1538 * and when we know whether the fault was overall successful.
1540 css_get(&memcg->css);
1541 current->memcg_in_oom = memcg;
1542 current->memcg_oom_gfp_mask = mask;
1543 current->memcg_oom_order = order;
1547 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1548 * @handle: actually kill/wait or just clean up the OOM state
1550 * This has to be called at the end of a page fault if the memcg OOM
1551 * handler was enabled.
1553 * Memcg supports userspace OOM handling where failed allocations must
1554 * sleep on a waitqueue until the userspace task resolves the
1555 * situation. Sleeping directly in the charge context with all kinds
1556 * of locks held is not a good idea, instead we remember an OOM state
1557 * in the task and mem_cgroup_oom_synchronize() has to be called at
1558 * the end of the page fault to complete the OOM handling.
1560 * Returns %true if an ongoing memcg OOM situation was detected and
1561 * completed, %false otherwise.
1563 bool mem_cgroup_oom_synchronize(bool handle)
1565 struct mem_cgroup *memcg = current->memcg_in_oom;
1566 struct oom_wait_info owait;
1569 /* OOM is global, do not handle */
1576 owait.memcg = memcg;
1577 owait.wait.flags = 0;
1578 owait.wait.func = memcg_oom_wake_function;
1579 owait.wait.private = current;
1580 INIT_LIST_HEAD(&owait.wait.task_list);
1582 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1583 mem_cgroup_mark_under_oom(memcg);
1585 locked = mem_cgroup_oom_trylock(memcg);
1588 mem_cgroup_oom_notify(memcg);
1590 if (locked && !memcg->oom_kill_disable) {
1591 mem_cgroup_unmark_under_oom(memcg);
1592 finish_wait(&memcg_oom_waitq, &owait.wait);
1593 mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
1594 current->memcg_oom_order);
1597 mem_cgroup_unmark_under_oom(memcg);
1598 finish_wait(&memcg_oom_waitq, &owait.wait);
1602 mem_cgroup_oom_unlock(memcg);
1604 * There is no guarantee that an OOM-lock contender
1605 * sees the wakeups triggered by the OOM kill
1606 * uncharges. Wake any sleepers explicitely.
1608 memcg_oom_recover(memcg);
1611 current->memcg_in_oom = NULL;
1612 css_put(&memcg->css);
1617 * lock_page_memcg - lock a page->mem_cgroup binding
1620 * This function protects unlocked LRU pages from being moved to
1621 * another cgroup and stabilizes their page->mem_cgroup binding.
1623 void lock_page_memcg(struct page *page)
1625 struct mem_cgroup *memcg;
1626 unsigned long flags;
1629 * The RCU lock is held throughout the transaction. The fast
1630 * path can get away without acquiring the memcg->move_lock
1631 * because page moving starts with an RCU grace period.
1635 if (mem_cgroup_disabled())
1638 memcg = page->mem_cgroup;
1639 if (unlikely(!memcg))
1642 if (atomic_read(&memcg->moving_account) <= 0)
1645 spin_lock_irqsave(&memcg->move_lock, flags);
1646 if (memcg != page->mem_cgroup) {
1647 spin_unlock_irqrestore(&memcg->move_lock, flags);
1652 * When charge migration first begins, we can have locked and
1653 * unlocked page stat updates happening concurrently. Track
1654 * the task who has the lock for unlock_page_memcg().
1656 memcg->move_lock_task = current;
1657 memcg->move_lock_flags = flags;
1661 EXPORT_SYMBOL(lock_page_memcg);
1664 * unlock_page_memcg - unlock a page->mem_cgroup binding
1667 void unlock_page_memcg(struct page *page)
1669 struct mem_cgroup *memcg = page->mem_cgroup;
1671 if (memcg && memcg->move_lock_task == current) {
1672 unsigned long flags = memcg->move_lock_flags;
1674 memcg->move_lock_task = NULL;
1675 memcg->move_lock_flags = 0;
1677 spin_unlock_irqrestore(&memcg->move_lock, flags);
1682 EXPORT_SYMBOL(unlock_page_memcg);
1685 * size of first charge trial. "32" comes from vmscan.c's magic value.
1686 * TODO: maybe necessary to use big numbers in big irons.
1688 #define CHARGE_BATCH 32U
1689 struct memcg_stock_pcp {
1690 struct mem_cgroup *cached; /* this never be root cgroup */
1691 unsigned int nr_pages;
1692 struct work_struct work;
1693 unsigned long flags;
1694 #define FLUSHING_CACHED_CHARGE 0
1696 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1697 static DEFINE_MUTEX(percpu_charge_mutex);
1700 * consume_stock: Try to consume stocked charge on this cpu.
1701 * @memcg: memcg to consume from.
1702 * @nr_pages: how many pages to charge.
1704 * The charges will only happen if @memcg matches the current cpu's memcg
1705 * stock, and at least @nr_pages are available in that stock. Failure to
1706 * service an allocation will refill the stock.
1708 * returns true if successful, false otherwise.
1710 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
1712 struct memcg_stock_pcp *stock;
1713 unsigned long flags;
1716 if (nr_pages > CHARGE_BATCH)
1719 local_irq_save(flags);
1721 stock = this_cpu_ptr(&memcg_stock);
1722 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
1723 stock->nr_pages -= nr_pages;
1727 local_irq_restore(flags);
1733 * Returns stocks cached in percpu and reset cached information.
1735 static void drain_stock(struct memcg_stock_pcp *stock)
1737 struct mem_cgroup *old = stock->cached;
1739 if (stock->nr_pages) {
1740 page_counter_uncharge(&old->memory, stock->nr_pages);
1741 if (do_memsw_account())
1742 page_counter_uncharge(&old->memsw, stock->nr_pages);
1743 css_put_many(&old->css, stock->nr_pages);
1744 stock->nr_pages = 0;
1746 stock->cached = NULL;
1749 static void drain_local_stock(struct work_struct *dummy)
1751 struct memcg_stock_pcp *stock;
1752 unsigned long flags;
1754 local_irq_save(flags);
1756 stock = this_cpu_ptr(&memcg_stock);
1758 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
1760 local_irq_restore(flags);
1764 * Cache charges(val) to local per_cpu area.
1765 * This will be consumed by consume_stock() function, later.
1767 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
1769 struct memcg_stock_pcp *stock;
1770 unsigned long flags;
1772 local_irq_save(flags);
1774 stock = this_cpu_ptr(&memcg_stock);
1775 if (stock->cached != memcg) { /* reset if necessary */
1777 stock->cached = memcg;
1779 stock->nr_pages += nr_pages;
1781 local_irq_restore(flags);
1785 * Drains all per-CPU charge caches for given root_memcg resp. subtree
1786 * of the hierarchy under it.
1788 static void drain_all_stock(struct mem_cgroup *root_memcg)
1792 /* If someone's already draining, avoid adding running more workers. */
1793 if (!mutex_trylock(&percpu_charge_mutex))
1795 /* Notify other cpus that system-wide "drain" is running */
1798 for_each_online_cpu(cpu) {
1799 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
1800 struct mem_cgroup *memcg;
1802 memcg = stock->cached;
1803 if (!memcg || !stock->nr_pages)
1805 if (!mem_cgroup_is_descendant(memcg, root_memcg))
1807 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
1809 drain_local_stock(&stock->work);
1811 schedule_work_on(cpu, &stock->work);
1816 mutex_unlock(&percpu_charge_mutex);
1819 static int memcg_cpu_hotplug_callback(struct notifier_block *nb,
1820 unsigned long action,
1823 int cpu = (unsigned long)hcpu;
1824 struct memcg_stock_pcp *stock;
1826 if (action == CPU_ONLINE)
1829 if (action != CPU_DEAD && action != CPU_DEAD_FROZEN)
1832 stock = &per_cpu(memcg_stock, cpu);
1837 static void reclaim_high(struct mem_cgroup *memcg,
1838 unsigned int nr_pages,
1842 if (page_counter_read(&memcg->memory) <= memcg->high)
1844 mem_cgroup_events(memcg, MEMCG_HIGH, 1);
1845 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
1846 } while ((memcg = parent_mem_cgroup(memcg)));
1849 static void high_work_func(struct work_struct *work)
1851 struct mem_cgroup *memcg;
1853 memcg = container_of(work, struct mem_cgroup, high_work);
1854 reclaim_high(memcg, CHARGE_BATCH, GFP_KERNEL);
1858 * Scheduled by try_charge() to be executed from the userland return path
1859 * and reclaims memory over the high limit.
1861 void mem_cgroup_handle_over_high(void)
1863 unsigned int nr_pages = current->memcg_nr_pages_over_high;
1864 struct mem_cgroup *memcg;
1866 if (likely(!nr_pages))
1869 memcg = get_mem_cgroup_from_mm(current->mm);
1870 reclaim_high(memcg, nr_pages, GFP_KERNEL);
1871 css_put(&memcg->css);
1872 current->memcg_nr_pages_over_high = 0;
1875 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
1876 unsigned int nr_pages)
1878 unsigned int batch = max(CHARGE_BATCH, nr_pages);
1879 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
1880 struct mem_cgroup *mem_over_limit;
1881 struct page_counter *counter;
1882 unsigned long nr_reclaimed;
1883 bool may_swap = true;
1884 bool drained = false;
1886 if (mem_cgroup_is_root(memcg))
1889 if (consume_stock(memcg, nr_pages))
1892 if (!do_memsw_account() ||
1893 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
1894 if (page_counter_try_charge(&memcg->memory, batch, &counter))
1896 if (do_memsw_account())
1897 page_counter_uncharge(&memcg->memsw, batch);
1898 mem_over_limit = mem_cgroup_from_counter(counter, memory);
1900 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
1904 if (batch > nr_pages) {
1910 * Unlike in global OOM situations, memcg is not in a physical
1911 * memory shortage. Allow dying and OOM-killed tasks to
1912 * bypass the last charges so that they can exit quickly and
1913 * free their memory.
1915 if (unlikely(test_thread_flag(TIF_MEMDIE) ||
1916 fatal_signal_pending(current) ||
1917 current->flags & PF_EXITING))
1921 * Prevent unbounded recursion when reclaim operations need to
1922 * allocate memory. This might exceed the limits temporarily,
1923 * but we prefer facilitating memory reclaim and getting back
1924 * under the limit over triggering OOM kills in these cases.
1926 if (unlikely(current->flags & PF_MEMALLOC))
1929 if (unlikely(task_in_memcg_oom(current)))
1932 if (!gfpflags_allow_blocking(gfp_mask))
1935 mem_cgroup_events(mem_over_limit, MEMCG_MAX, 1);
1937 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
1938 gfp_mask, may_swap);
1940 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
1944 drain_all_stock(mem_over_limit);
1949 if (gfp_mask & __GFP_NORETRY)
1952 * Even though the limit is exceeded at this point, reclaim
1953 * may have been able to free some pages. Retry the charge
1954 * before killing the task.
1956 * Only for regular pages, though: huge pages are rather
1957 * unlikely to succeed so close to the limit, and we fall back
1958 * to regular pages anyway in case of failure.
1960 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
1963 * At task move, charge accounts can be doubly counted. So, it's
1964 * better to wait until the end of task_move if something is going on.
1966 if (mem_cgroup_wait_acct_move(mem_over_limit))
1972 if (gfp_mask & __GFP_NOFAIL)
1975 if (fatal_signal_pending(current))
1978 mem_cgroup_events(mem_over_limit, MEMCG_OOM, 1);
1980 mem_cgroup_oom(mem_over_limit, gfp_mask,
1981 get_order(nr_pages * PAGE_SIZE));
1983 if (!(gfp_mask & __GFP_NOFAIL))
1987 * The allocation either can't fail or will lead to more memory
1988 * being freed very soon. Allow memory usage go over the limit
1989 * temporarily by force charging it.
1991 page_counter_charge(&memcg->memory, nr_pages);
1992 if (do_memsw_account())
1993 page_counter_charge(&memcg->memsw, nr_pages);
1994 css_get_many(&memcg->css, nr_pages);
1999 css_get_many(&memcg->css, batch);
2000 if (batch > nr_pages)
2001 refill_stock(memcg, batch - nr_pages);
2004 * If the hierarchy is above the normal consumption range, schedule
2005 * reclaim on returning to userland. We can perform reclaim here
2006 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2007 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2008 * not recorded as it most likely matches current's and won't
2009 * change in the meantime. As high limit is checked again before
2010 * reclaim, the cost of mismatch is negligible.
2013 if (page_counter_read(&memcg->memory) > memcg->high) {
2014 /* Don't bother a random interrupted task */
2015 if (in_interrupt()) {
2016 schedule_work(&memcg->high_work);
2019 current->memcg_nr_pages_over_high += batch;
2020 set_notify_resume(current);
2023 } while ((memcg = parent_mem_cgroup(memcg)));
2028 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2030 if (mem_cgroup_is_root(memcg))
2033 page_counter_uncharge(&memcg->memory, nr_pages);
2034 if (do_memsw_account())
2035 page_counter_uncharge(&memcg->memsw, nr_pages);
2037 css_put_many(&memcg->css, nr_pages);
2040 static void lock_page_lru(struct page *page, int *isolated)
2042 struct zone *zone = page_zone(page);
2044 spin_lock_irq(zone_lru_lock(zone));
2045 if (PageLRU(page)) {
2046 struct lruvec *lruvec;
2048 lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
2050 del_page_from_lru_list(page, lruvec, page_lru(page));
2056 static void unlock_page_lru(struct page *page, int isolated)
2058 struct zone *zone = page_zone(page);
2061 struct lruvec *lruvec;
2063 lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
2064 VM_BUG_ON_PAGE(PageLRU(page), page);
2066 add_page_to_lru_list(page, lruvec, page_lru(page));
2068 spin_unlock_irq(zone_lru_lock(zone));
2071 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2076 VM_BUG_ON_PAGE(page->mem_cgroup, page);
2079 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2080 * may already be on some other mem_cgroup's LRU. Take care of it.
2083 lock_page_lru(page, &isolated);
2086 * Nobody should be changing or seriously looking at
2087 * page->mem_cgroup at this point:
2089 * - the page is uncharged
2091 * - the page is off-LRU
2093 * - an anonymous fault has exclusive page access, except for
2094 * a locked page table
2096 * - a page cache insertion, a swapin fault, or a migration
2097 * have the page locked
2099 page->mem_cgroup = memcg;
2102 unlock_page_lru(page, isolated);
2106 static int memcg_alloc_cache_id(void)
2111 id = ida_simple_get(&memcg_cache_ida,
2112 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2116 if (id < memcg_nr_cache_ids)
2120 * There's no space for the new id in memcg_caches arrays,
2121 * so we have to grow them.
2123 down_write(&memcg_cache_ids_sem);
2125 size = 2 * (id + 1);
2126 if (size < MEMCG_CACHES_MIN_SIZE)
2127 size = MEMCG_CACHES_MIN_SIZE;
2128 else if (size > MEMCG_CACHES_MAX_SIZE)
2129 size = MEMCG_CACHES_MAX_SIZE;
2131 err = memcg_update_all_caches(size);
2133 err = memcg_update_all_list_lrus(size);
2135 memcg_nr_cache_ids = size;
2137 up_write(&memcg_cache_ids_sem);
2140 ida_simple_remove(&memcg_cache_ida, id);
2146 static void memcg_free_cache_id(int id)
2148 ida_simple_remove(&memcg_cache_ida, id);
2151 struct memcg_kmem_cache_create_work {
2152 struct mem_cgroup *memcg;
2153 struct kmem_cache *cachep;
2154 struct work_struct work;
2157 static void memcg_kmem_cache_create_func(struct work_struct *w)
2159 struct memcg_kmem_cache_create_work *cw =
2160 container_of(w, struct memcg_kmem_cache_create_work, work);
2161 struct mem_cgroup *memcg = cw->memcg;
2162 struct kmem_cache *cachep = cw->cachep;
2164 memcg_create_kmem_cache(memcg, cachep);
2166 css_put(&memcg->css);
2171 * Enqueue the creation of a per-memcg kmem_cache.
2173 static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
2174 struct kmem_cache *cachep)
2176 struct memcg_kmem_cache_create_work *cw;
2178 cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
2182 css_get(&memcg->css);
2185 cw->cachep = cachep;
2186 INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
2188 schedule_work(&cw->work);
2191 static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
2192 struct kmem_cache *cachep)
2195 * We need to stop accounting when we kmalloc, because if the
2196 * corresponding kmalloc cache is not yet created, the first allocation
2197 * in __memcg_schedule_kmem_cache_create will recurse.
2199 * However, it is better to enclose the whole function. Depending on
2200 * the debugging options enabled, INIT_WORK(), for instance, can
2201 * trigger an allocation. This too, will make us recurse. Because at
2202 * this point we can't allow ourselves back into memcg_kmem_get_cache,
2203 * the safest choice is to do it like this, wrapping the whole function.
2205 current->memcg_kmem_skip_account = 1;
2206 __memcg_schedule_kmem_cache_create(memcg, cachep);
2207 current->memcg_kmem_skip_account = 0;
2210 static inline bool memcg_kmem_bypass(void)
2212 if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
2218 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2219 * @cachep: the original global kmem cache
2221 * Return the kmem_cache we're supposed to use for a slab allocation.
2222 * We try to use the current memcg's version of the cache.
2224 * If the cache does not exist yet, if we are the first user of it, we
2225 * create it asynchronously in a workqueue and let the current allocation
2226 * go through with the original cache.
2228 * This function takes a reference to the cache it returns to assure it
2229 * won't get destroyed while we are working with it. Once the caller is
2230 * done with it, memcg_kmem_put_cache() must be called to release the
2233 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
2235 struct mem_cgroup *memcg;
2236 struct kmem_cache *memcg_cachep;
2239 VM_BUG_ON(!is_root_cache(cachep));
2241 if (memcg_kmem_bypass())
2244 if (current->memcg_kmem_skip_account)
2247 memcg = get_mem_cgroup_from_mm(current->mm);
2248 kmemcg_id = READ_ONCE(memcg->kmemcg_id);
2252 memcg_cachep = cache_from_memcg_idx(cachep, kmemcg_id);
2253 if (likely(memcg_cachep))
2254 return memcg_cachep;
2257 * If we are in a safe context (can wait, and not in interrupt
2258 * context), we could be be predictable and return right away.
2259 * This would guarantee that the allocation being performed
2260 * already belongs in the new cache.
2262 * However, there are some clashes that can arrive from locking.
2263 * For instance, because we acquire the slab_mutex while doing
2264 * memcg_create_kmem_cache, this means no further allocation
2265 * could happen with the slab_mutex held. So it's better to
2268 memcg_schedule_kmem_cache_create(memcg, cachep);
2270 css_put(&memcg->css);
2275 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2276 * @cachep: the cache returned by memcg_kmem_get_cache
2278 void memcg_kmem_put_cache(struct kmem_cache *cachep)
2280 if (!is_root_cache(cachep))
2281 css_put(&cachep->memcg_params.memcg->css);
2285 * memcg_kmem_charge: charge a kmem page
2286 * @page: page to charge
2287 * @gfp: reclaim mode
2288 * @order: allocation order
2289 * @memcg: memory cgroup to charge
2291 * Returns 0 on success, an error code on failure.
2293 int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
2294 struct mem_cgroup *memcg)
2296 unsigned int nr_pages = 1 << order;
2297 struct page_counter *counter;
2300 ret = try_charge(memcg, gfp, nr_pages);
2304 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
2305 !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
2306 cancel_charge(memcg, nr_pages);
2310 page->mem_cgroup = memcg;
2316 * memcg_kmem_charge: charge a kmem page to the current memory cgroup
2317 * @page: page to charge
2318 * @gfp: reclaim mode
2319 * @order: allocation order
2321 * Returns 0 on success, an error code on failure.
2323 int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
2325 struct mem_cgroup *memcg;
2328 if (memcg_kmem_bypass())
2331 memcg = get_mem_cgroup_from_mm(current->mm);
2332 if (!mem_cgroup_is_root(memcg)) {
2333 ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
2335 __SetPageKmemcg(page);
2337 css_put(&memcg->css);
2341 * memcg_kmem_uncharge: uncharge a kmem page
2342 * @page: page to uncharge
2343 * @order: allocation order
2345 void memcg_kmem_uncharge(struct page *page, int order)
2347 struct mem_cgroup *memcg = page->mem_cgroup;
2348 unsigned int nr_pages = 1 << order;
2353 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
2355 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2356 page_counter_uncharge(&memcg->kmem, nr_pages);
2358 page_counter_uncharge(&memcg->memory, nr_pages);
2359 if (do_memsw_account())
2360 page_counter_uncharge(&memcg->memsw, nr_pages);
2362 page->mem_cgroup = NULL;
2364 /* slab pages do not have PageKmemcg flag set */
2365 if (PageKmemcg(page))
2366 __ClearPageKmemcg(page);
2368 css_put_many(&memcg->css, nr_pages);
2370 #endif /* !CONFIG_SLOB */
2372 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2375 * Because tail pages are not marked as "used", set it. We're under
2376 * zone_lru_lock and migration entries setup in all page mappings.
2378 void mem_cgroup_split_huge_fixup(struct page *head)
2382 if (mem_cgroup_disabled())
2385 for (i = 1; i < HPAGE_PMD_NR; i++)
2386 head[i].mem_cgroup = head->mem_cgroup;
2388 __this_cpu_sub(head->mem_cgroup->stat->count[MEM_CGROUP_STAT_RSS_HUGE],
2391 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2393 #ifdef CONFIG_MEMCG_SWAP
2394 static void mem_cgroup_swap_statistics(struct mem_cgroup *memcg,
2397 int val = (charge) ? 1 : -1;
2398 this_cpu_add(memcg->stat->count[MEM_CGROUP_STAT_SWAP], val);
2402 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2403 * @entry: swap entry to be moved
2404 * @from: mem_cgroup which the entry is moved from
2405 * @to: mem_cgroup which the entry is moved to
2407 * It succeeds only when the swap_cgroup's record for this entry is the same
2408 * as the mem_cgroup's id of @from.
2410 * Returns 0 on success, -EINVAL on failure.
2412 * The caller must have charged to @to, IOW, called page_counter_charge() about
2413 * both res and memsw, and called css_get().
2415 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2416 struct mem_cgroup *from, struct mem_cgroup *to)
2418 unsigned short old_id, new_id;
2420 old_id = mem_cgroup_id(from);
2421 new_id = mem_cgroup_id(to);
2423 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2424 mem_cgroup_swap_statistics(from, false);
2425 mem_cgroup_swap_statistics(to, true);
2431 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2432 struct mem_cgroup *from, struct mem_cgroup *to)
2438 static DEFINE_MUTEX(memcg_limit_mutex);
2440 static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
2441 unsigned long limit)
2443 unsigned long curusage;
2444 unsigned long oldusage;
2445 bool enlarge = false;
2450 * For keeping hierarchical_reclaim simple, how long we should retry
2451 * is depends on callers. We set our retry-count to be function
2452 * of # of children which we should visit in this loop.
2454 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
2455 mem_cgroup_count_children(memcg);
2457 oldusage = page_counter_read(&memcg->memory);
2460 if (signal_pending(current)) {
2465 mutex_lock(&memcg_limit_mutex);
2466 if (limit > memcg->memsw.limit) {
2467 mutex_unlock(&memcg_limit_mutex);
2471 if (limit > memcg->memory.limit)
2473 ret = page_counter_limit(&memcg->memory, limit);
2474 mutex_unlock(&memcg_limit_mutex);
2479 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, true);
2481 curusage = page_counter_read(&memcg->memory);
2482 /* Usage is reduced ? */
2483 if (curusage >= oldusage)
2486 oldusage = curusage;
2487 } while (retry_count);
2489 if (!ret && enlarge)
2490 memcg_oom_recover(memcg);
2495 static int mem_cgroup_resize_memsw_limit(struct mem_cgroup *memcg,
2496 unsigned long limit)
2498 unsigned long curusage;
2499 unsigned long oldusage;
2500 bool enlarge = false;
2504 /* see mem_cgroup_resize_res_limit */
2505 retry_count = MEM_CGROUP_RECLAIM_RETRIES *
2506 mem_cgroup_count_children(memcg);
2508 oldusage = page_counter_read(&memcg->memsw);
2511 if (signal_pending(current)) {
2516 mutex_lock(&memcg_limit_mutex);
2517 if (limit < memcg->memory.limit) {
2518 mutex_unlock(&memcg_limit_mutex);
2522 if (limit > memcg->memsw.limit)
2524 ret = page_counter_limit(&memcg->memsw, limit);
2525 mutex_unlock(&memcg_limit_mutex);
2530 try_to_free_mem_cgroup_pages(memcg, 1, GFP_KERNEL, false);
2532 curusage = page_counter_read(&memcg->memsw);
2533 /* Usage is reduced ? */
2534 if (curusage >= oldusage)
2537 oldusage = curusage;
2538 } while (retry_count);
2540 if (!ret && enlarge)
2541 memcg_oom_recover(memcg);
2546 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
2548 unsigned long *total_scanned)
2550 unsigned long nr_reclaimed = 0;
2551 struct mem_cgroup_per_node *mz, *next_mz = NULL;
2552 unsigned long reclaimed;
2554 struct mem_cgroup_tree_per_node *mctz;
2555 unsigned long excess;
2556 unsigned long nr_scanned;
2561 mctz = soft_limit_tree_node(pgdat->node_id);
2564 * Do not even bother to check the largest node if the root
2565 * is empty. Do it lockless to prevent lock bouncing. Races
2566 * are acceptable as soft limit is best effort anyway.
2568 if (RB_EMPTY_ROOT(&mctz->rb_root))
2572 * This loop can run a while, specially if mem_cgroup's continuously
2573 * keep exceeding their soft limit and putting the system under
2580 mz = mem_cgroup_largest_soft_limit_node(mctz);
2585 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
2586 gfp_mask, &nr_scanned);
2587 nr_reclaimed += reclaimed;
2588 *total_scanned += nr_scanned;
2589 spin_lock_irq(&mctz->lock);
2590 __mem_cgroup_remove_exceeded(mz, mctz);
2593 * If we failed to reclaim anything from this memory cgroup
2594 * it is time to move on to the next cgroup
2598 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
2600 excess = soft_limit_excess(mz->memcg);
2602 * One school of thought says that we should not add
2603 * back the node to the tree if reclaim returns 0.
2604 * But our reclaim could return 0, simply because due
2605 * to priority we are exposing a smaller subset of
2606 * memory to reclaim from. Consider this as a longer
2609 /* If excess == 0, no tree ops */
2610 __mem_cgroup_insert_exceeded(mz, mctz, excess);
2611 spin_unlock_irq(&mctz->lock);
2612 css_put(&mz->memcg->css);
2615 * Could not reclaim anything and there are no more
2616 * mem cgroups to try or we seem to be looping without
2617 * reclaiming anything.
2619 if (!nr_reclaimed &&
2621 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
2623 } while (!nr_reclaimed);
2625 css_put(&next_mz->memcg->css);
2626 return nr_reclaimed;
2630 * Test whether @memcg has children, dead or alive. Note that this
2631 * function doesn't care whether @memcg has use_hierarchy enabled and
2632 * returns %true if there are child csses according to the cgroup
2633 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
2635 static inline bool memcg_has_children(struct mem_cgroup *memcg)
2640 ret = css_next_child(NULL, &memcg->css);
2646 * Reclaims as many pages from the given memcg as possible.
2648 * Caller is responsible for holding css reference for memcg.
2650 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
2652 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2654 /* we call try-to-free pages for make this cgroup empty */
2655 lru_add_drain_all();
2656 /* try to free all pages in this cgroup */
2657 while (nr_retries && page_counter_read(&memcg->memory)) {
2660 if (signal_pending(current))
2663 progress = try_to_free_mem_cgroup_pages(memcg, 1,
2667 /* maybe some writeback is necessary */
2668 congestion_wait(BLK_RW_ASYNC, HZ/10);
2676 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
2677 char *buf, size_t nbytes,
2680 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
2682 if (mem_cgroup_is_root(memcg))
2684 return mem_cgroup_force_empty(memcg) ?: nbytes;
2687 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
2690 return mem_cgroup_from_css(css)->use_hierarchy;
2693 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
2694 struct cftype *cft, u64 val)
2697 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
2698 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
2700 if (memcg->use_hierarchy == val)
2704 * If parent's use_hierarchy is set, we can't make any modifications
2705 * in the child subtrees. If it is unset, then the change can
2706 * occur, provided the current cgroup has no children.
2708 * For the root cgroup, parent_mem is NULL, we allow value to be
2709 * set if there are no children.
2711 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
2712 (val == 1 || val == 0)) {
2713 if (!memcg_has_children(memcg))
2714 memcg->use_hierarchy = val;
2723 static void tree_stat(struct mem_cgroup *memcg, unsigned long *stat)
2725 struct mem_cgroup *iter;
2728 memset(stat, 0, sizeof(*stat) * MEMCG_NR_STAT);
2730 for_each_mem_cgroup_tree(iter, memcg) {
2731 for (i = 0; i < MEMCG_NR_STAT; i++)
2732 stat[i] += mem_cgroup_read_stat(iter, i);
2736 static void tree_events(struct mem_cgroup *memcg, unsigned long *events)
2738 struct mem_cgroup *iter;
2741 memset(events, 0, sizeof(*events) * MEMCG_NR_EVENTS);
2743 for_each_mem_cgroup_tree(iter, memcg) {
2744 for (i = 0; i < MEMCG_NR_EVENTS; i++)
2745 events[i] += mem_cgroup_read_events(iter, i);
2749 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
2751 unsigned long val = 0;
2753 if (mem_cgroup_is_root(memcg)) {
2754 struct mem_cgroup *iter;
2756 for_each_mem_cgroup_tree(iter, memcg) {
2757 val += mem_cgroup_read_stat(iter,
2758 MEM_CGROUP_STAT_CACHE);
2759 val += mem_cgroup_read_stat(iter,
2760 MEM_CGROUP_STAT_RSS);
2762 val += mem_cgroup_read_stat(iter,
2763 MEM_CGROUP_STAT_SWAP);
2767 val = page_counter_read(&memcg->memory);
2769 val = page_counter_read(&memcg->memsw);
2782 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
2785 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
2786 struct page_counter *counter;
2788 switch (MEMFILE_TYPE(cft->private)) {
2790 counter = &memcg->memory;
2793 counter = &memcg->memsw;
2796 counter = &memcg->kmem;
2799 counter = &memcg->tcpmem;
2805 switch (MEMFILE_ATTR(cft->private)) {
2807 if (counter == &memcg->memory)
2808 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
2809 if (counter == &memcg->memsw)
2810 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
2811 return (u64)page_counter_read(counter) * PAGE_SIZE;
2813 return (u64)counter->limit * PAGE_SIZE;
2815 return (u64)counter->watermark * PAGE_SIZE;
2817 return counter->failcnt;
2818 case RES_SOFT_LIMIT:
2819 return (u64)memcg->soft_limit * PAGE_SIZE;
2826 static int memcg_online_kmem(struct mem_cgroup *memcg)
2830 if (cgroup_memory_nokmem)
2833 BUG_ON(memcg->kmemcg_id >= 0);
2834 BUG_ON(memcg->kmem_state);
2836 memcg_id = memcg_alloc_cache_id();
2840 static_branch_inc(&memcg_kmem_enabled_key);
2842 * A memory cgroup is considered kmem-online as soon as it gets
2843 * kmemcg_id. Setting the id after enabling static branching will
2844 * guarantee no one starts accounting before all call sites are
2847 memcg->kmemcg_id = memcg_id;
2848 memcg->kmem_state = KMEM_ONLINE;
2853 static void memcg_offline_kmem(struct mem_cgroup *memcg)
2855 struct cgroup_subsys_state *css;
2856 struct mem_cgroup *parent, *child;
2859 if (memcg->kmem_state != KMEM_ONLINE)
2862 * Clear the online state before clearing memcg_caches array
2863 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
2864 * guarantees that no cache will be created for this cgroup
2865 * after we are done (see memcg_create_kmem_cache()).
2867 memcg->kmem_state = KMEM_ALLOCATED;
2869 memcg_deactivate_kmem_caches(memcg);
2871 kmemcg_id = memcg->kmemcg_id;
2872 BUG_ON(kmemcg_id < 0);
2874 parent = parent_mem_cgroup(memcg);
2876 parent = root_mem_cgroup;
2879 * Change kmemcg_id of this cgroup and all its descendants to the
2880 * parent's id, and then move all entries from this cgroup's list_lrus
2881 * to ones of the parent. After we have finished, all list_lrus
2882 * corresponding to this cgroup are guaranteed to remain empty. The
2883 * ordering is imposed by list_lru_node->lock taken by
2884 * memcg_drain_all_list_lrus().
2886 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
2887 css_for_each_descendant_pre(css, &memcg->css) {
2888 child = mem_cgroup_from_css(css);
2889 BUG_ON(child->kmemcg_id != kmemcg_id);
2890 child->kmemcg_id = parent->kmemcg_id;
2891 if (!memcg->use_hierarchy)
2896 memcg_drain_all_list_lrus(kmemcg_id, parent->kmemcg_id);
2898 memcg_free_cache_id(kmemcg_id);
2901 static void memcg_free_kmem(struct mem_cgroup *memcg)
2903 /* css_alloc() failed, offlining didn't happen */
2904 if (unlikely(memcg->kmem_state == KMEM_ONLINE))
2905 memcg_offline_kmem(memcg);
2907 if (memcg->kmem_state == KMEM_ALLOCATED) {
2908 memcg_destroy_kmem_caches(memcg);
2909 static_branch_dec(&memcg_kmem_enabled_key);
2910 WARN_ON(page_counter_read(&memcg->kmem));
2914 static int memcg_online_kmem(struct mem_cgroup *memcg)
2918 static void memcg_offline_kmem(struct mem_cgroup *memcg)
2921 static void memcg_free_kmem(struct mem_cgroup *memcg)
2924 #endif /* !CONFIG_SLOB */
2926 static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
2927 unsigned long limit)
2931 mutex_lock(&memcg_limit_mutex);
2932 ret = page_counter_limit(&memcg->kmem, limit);
2933 mutex_unlock(&memcg_limit_mutex);
2937 static int memcg_update_tcp_limit(struct mem_cgroup *memcg, unsigned long limit)
2941 mutex_lock(&memcg_limit_mutex);
2943 ret = page_counter_limit(&memcg->tcpmem, limit);
2947 if (!memcg->tcpmem_active) {
2949 * The active flag needs to be written after the static_key
2950 * update. This is what guarantees that the socket activation
2951 * function is the last one to run. See mem_cgroup_sk_alloc()
2952 * for details, and note that we don't mark any socket as
2953 * belonging to this memcg until that flag is up.
2955 * We need to do this, because static_keys will span multiple
2956 * sites, but we can't control their order. If we mark a socket
2957 * as accounted, but the accounting functions are not patched in
2958 * yet, we'll lose accounting.
2960 * We never race with the readers in mem_cgroup_sk_alloc(),
2961 * because when this value change, the code to process it is not
2964 static_branch_inc(&memcg_sockets_enabled_key);
2965 memcg->tcpmem_active = true;
2968 mutex_unlock(&memcg_limit_mutex);
2973 * The user of this function is...
2976 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
2977 char *buf, size_t nbytes, loff_t off)
2979 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
2980 unsigned long nr_pages;
2983 buf = strstrip(buf);
2984 ret = page_counter_memparse(buf, "-1", &nr_pages);
2988 switch (MEMFILE_ATTR(of_cft(of)->private)) {
2990 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
2994 switch (MEMFILE_TYPE(of_cft(of)->private)) {
2996 ret = mem_cgroup_resize_limit(memcg, nr_pages);
2999 ret = mem_cgroup_resize_memsw_limit(memcg, nr_pages);
3002 ret = memcg_update_kmem_limit(memcg, nr_pages);
3005 ret = memcg_update_tcp_limit(memcg, nr_pages);
3009 case RES_SOFT_LIMIT:
3010 memcg->soft_limit = nr_pages;
3014 return ret ?: nbytes;
3017 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3018 size_t nbytes, loff_t off)
3020 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3021 struct page_counter *counter;
3023 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3025 counter = &memcg->memory;
3028 counter = &memcg->memsw;
3031 counter = &memcg->kmem;
3034 counter = &memcg->tcpmem;
3040 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3042 page_counter_reset_watermark(counter);
3045 counter->failcnt = 0;
3054 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3057 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3061 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3062 struct cftype *cft, u64 val)
3064 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3066 if (val & ~MOVE_MASK)
3070 * No kind of locking is needed in here, because ->can_attach() will
3071 * check this value once in the beginning of the process, and then carry
3072 * on with stale data. This means that changes to this value will only
3073 * affect task migrations starting after the change.
3075 memcg->move_charge_at_immigrate = val;
3079 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3080 struct cftype *cft, u64 val)
3087 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3091 unsigned int lru_mask;
3094 static const struct numa_stat stats[] = {
3095 { "total", LRU_ALL },
3096 { "file", LRU_ALL_FILE },
3097 { "anon", LRU_ALL_ANON },
3098 { "unevictable", BIT(LRU_UNEVICTABLE) },
3100 const struct numa_stat *stat;
3103 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3105 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3106 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
3107 seq_printf(m, "%s=%lu", stat->name, nr);
3108 for_each_node_state(nid, N_MEMORY) {
3109 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
3111 seq_printf(m, " N%d=%lu", nid, nr);
3116 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3117 struct mem_cgroup *iter;
3120 for_each_mem_cgroup_tree(iter, memcg)
3121 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
3122 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
3123 for_each_node_state(nid, N_MEMORY) {
3125 for_each_mem_cgroup_tree(iter, memcg)
3126 nr += mem_cgroup_node_nr_lru_pages(
3127 iter, nid, stat->lru_mask);
3128 seq_printf(m, " N%d=%lu", nid, nr);
3135 #endif /* CONFIG_NUMA */
3137 static int memcg_stat_show(struct seq_file *m, void *v)
3139 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3140 unsigned long memory, memsw;
3141 struct mem_cgroup *mi;
3144 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_stat_names) !=
3145 MEM_CGROUP_STAT_NSTATS);
3146 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_events_names) !=
3147 MEM_CGROUP_EVENTS_NSTATS);
3148 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
3150 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3151 if (i == MEM_CGROUP_STAT_SWAP && !do_memsw_account())
3153 seq_printf(m, "%s %lu\n", mem_cgroup_stat_names[i],
3154 mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
3157 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
3158 seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
3159 mem_cgroup_read_events(memcg, i));
3161 for (i = 0; i < NR_LRU_LISTS; i++)
3162 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
3163 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
3165 /* Hierarchical information */
3166 memory = memsw = PAGE_COUNTER_MAX;
3167 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
3168 memory = min(memory, mi->memory.limit);
3169 memsw = min(memsw, mi->memsw.limit);
3171 seq_printf(m, "hierarchical_memory_limit %llu\n",
3172 (u64)memory * PAGE_SIZE);
3173 if (do_memsw_account())
3174 seq_printf(m, "hierarchical_memsw_limit %llu\n",
3175 (u64)memsw * PAGE_SIZE);
3177 for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
3178 unsigned long long val = 0;
3180 if (i == MEM_CGROUP_STAT_SWAP && !do_memsw_account())
3182 for_each_mem_cgroup_tree(mi, memcg)
3183 val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
3184 seq_printf(m, "total_%s %llu\n", mem_cgroup_stat_names[i], val);
3187 for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
3188 unsigned long long val = 0;
3190 for_each_mem_cgroup_tree(mi, memcg)
3191 val += mem_cgroup_read_events(mi, i);
3192 seq_printf(m, "total_%s %llu\n",
3193 mem_cgroup_events_names[i], val);
3196 for (i = 0; i < NR_LRU_LISTS; i++) {
3197 unsigned long long val = 0;
3199 for_each_mem_cgroup_tree(mi, memcg)
3200 val += mem_cgroup_nr_lru_pages(mi, BIT(i)) * PAGE_SIZE;
3201 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i], val);
3204 #ifdef CONFIG_DEBUG_VM
3207 struct mem_cgroup_per_node *mz;
3208 struct zone_reclaim_stat *rstat;
3209 unsigned long recent_rotated[2] = {0, 0};
3210 unsigned long recent_scanned[2] = {0, 0};
3212 for_each_online_pgdat(pgdat) {
3213 mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
3214 rstat = &mz->lruvec.reclaim_stat;
3216 recent_rotated[0] += rstat->recent_rotated[0];
3217 recent_rotated[1] += rstat->recent_rotated[1];
3218 recent_scanned[0] += rstat->recent_scanned[0];
3219 recent_scanned[1] += rstat->recent_scanned[1];
3221 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
3222 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
3223 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
3224 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
3231 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
3234 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3236 return mem_cgroup_swappiness(memcg);
3239 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
3240 struct cftype *cft, u64 val)
3242 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3248 memcg->swappiness = val;
3250 vm_swappiness = val;
3255 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3257 struct mem_cgroup_threshold_ary *t;
3258 unsigned long usage;
3263 t = rcu_dereference(memcg->thresholds.primary);
3265 t = rcu_dereference(memcg->memsw_thresholds.primary);
3270 usage = mem_cgroup_usage(memcg, swap);
3273 * current_threshold points to threshold just below or equal to usage.
3274 * If it's not true, a threshold was crossed after last
3275 * call of __mem_cgroup_threshold().
3277 i = t->current_threshold;
3280 * Iterate backward over array of thresholds starting from
3281 * current_threshold and check if a threshold is crossed.
3282 * If none of thresholds below usage is crossed, we read
3283 * only one element of the array here.
3285 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3286 eventfd_signal(t->entries[i].eventfd, 1);
3288 /* i = current_threshold + 1 */
3292 * Iterate forward over array of thresholds starting from
3293 * current_threshold+1 and check if a threshold is crossed.
3294 * If none of thresholds above usage is crossed, we read
3295 * only one element of the array here.
3297 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3298 eventfd_signal(t->entries[i].eventfd, 1);
3300 /* Update current_threshold */
3301 t->current_threshold = i - 1;
3306 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3309 __mem_cgroup_threshold(memcg, false);
3310 if (do_memsw_account())
3311 __mem_cgroup_threshold(memcg, true);
3313 memcg = parent_mem_cgroup(memcg);
3317 static int compare_thresholds(const void *a, const void *b)
3319 const struct mem_cgroup_threshold *_a = a;
3320 const struct mem_cgroup_threshold *_b = b;
3322 if (_a->threshold > _b->threshold)
3325 if (_a->threshold < _b->threshold)
3331 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
3333 struct mem_cgroup_eventfd_list *ev;
3335 spin_lock(&memcg_oom_lock);
3337 list_for_each_entry(ev, &memcg->oom_notify, list)
3338 eventfd_signal(ev->eventfd, 1);
3340 spin_unlock(&memcg_oom_lock);
3344 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
3346 struct mem_cgroup *iter;
3348 for_each_mem_cgroup_tree(iter, memcg)
3349 mem_cgroup_oom_notify_cb(iter);
3352 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
3353 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
3355 struct mem_cgroup_thresholds *thresholds;
3356 struct mem_cgroup_threshold_ary *new;
3357 unsigned long threshold;
3358 unsigned long usage;
3361 ret = page_counter_memparse(args, "-1", &threshold);
3365 mutex_lock(&memcg->thresholds_lock);
3368 thresholds = &memcg->thresholds;
3369 usage = mem_cgroup_usage(memcg, false);
3370 } else if (type == _MEMSWAP) {
3371 thresholds = &memcg->memsw_thresholds;
3372 usage = mem_cgroup_usage(memcg, true);
3376 /* Check if a threshold crossed before adding a new one */
3377 if (thresholds->primary)
3378 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3380 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3382 /* Allocate memory for new array of thresholds */
3383 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3391 /* Copy thresholds (if any) to new array */
3392 if (thresholds->primary) {
3393 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3394 sizeof(struct mem_cgroup_threshold));
3397 /* Add new threshold */
3398 new->entries[size - 1].eventfd = eventfd;
3399 new->entries[size - 1].threshold = threshold;
3401 /* Sort thresholds. Registering of new threshold isn't time-critical */
3402 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3403 compare_thresholds, NULL);
3405 /* Find current threshold */
3406 new->current_threshold = -1;
3407 for (i = 0; i < size; i++) {
3408 if (new->entries[i].threshold <= usage) {
3410 * new->current_threshold will not be used until
3411 * rcu_assign_pointer(), so it's safe to increment
3414 ++new->current_threshold;
3419 /* Free old spare buffer and save old primary buffer as spare */
3420 kfree(thresholds->spare);
3421 thresholds->spare = thresholds->primary;
3423 rcu_assign_pointer(thresholds->primary, new);
3425 /* To be sure that nobody uses thresholds */
3429 mutex_unlock(&memcg->thresholds_lock);
3434 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
3435 struct eventfd_ctx *eventfd, const char *args)
3437 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
3440 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
3441 struct eventfd_ctx *eventfd, const char *args)
3443 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
3446 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3447 struct eventfd_ctx *eventfd, enum res_type type)
3449 struct mem_cgroup_thresholds *thresholds;
3450 struct mem_cgroup_threshold_ary *new;
3451 unsigned long usage;
3454 mutex_lock(&memcg->thresholds_lock);
3457 thresholds = &memcg->thresholds;
3458 usage = mem_cgroup_usage(memcg, false);
3459 } else if (type == _MEMSWAP) {
3460 thresholds = &memcg->memsw_thresholds;
3461 usage = mem_cgroup_usage(memcg, true);
3465 if (!thresholds->primary)
3468 /* Check if a threshold crossed before removing */
3469 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3471 /* Calculate new number of threshold */
3473 for (i = 0; i < thresholds->primary->size; i++) {
3474 if (thresholds->primary->entries[i].eventfd != eventfd)
3478 new = thresholds->spare;
3480 /* Set thresholds array to NULL if we don't have thresholds */
3489 /* Copy thresholds and find current threshold */
3490 new->current_threshold = -1;
3491 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
3492 if (thresholds->primary->entries[i].eventfd == eventfd)
3495 new->entries[j] = thresholds->primary->entries[i];
3496 if (new->entries[j].threshold <= usage) {
3498 * new->current_threshold will not be used
3499 * until rcu_assign_pointer(), so it's safe to increment
3502 ++new->current_threshold;
3508 /* Swap primary and spare array */
3509 thresholds->spare = thresholds->primary;
3511 rcu_assign_pointer(thresholds->primary, new);
3513 /* To be sure that nobody uses thresholds */
3516 /* If all events are unregistered, free the spare array */
3518 kfree(thresholds->spare);
3519 thresholds->spare = NULL;
3522 mutex_unlock(&memcg->thresholds_lock);
3525 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3526 struct eventfd_ctx *eventfd)
3528 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
3531 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3532 struct eventfd_ctx *eventfd)
3534 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
3537 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
3538 struct eventfd_ctx *eventfd, const char *args)
3540 struct mem_cgroup_eventfd_list *event;
3542 event = kmalloc(sizeof(*event), GFP_KERNEL);
3546 spin_lock(&memcg_oom_lock);
3548 event->eventfd = eventfd;
3549 list_add(&event->list, &memcg->oom_notify);
3551 /* already in OOM ? */
3552 if (memcg->under_oom)
3553 eventfd_signal(eventfd, 1);
3554 spin_unlock(&memcg_oom_lock);
3559 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
3560 struct eventfd_ctx *eventfd)
3562 struct mem_cgroup_eventfd_list *ev, *tmp;
3564 spin_lock(&memcg_oom_lock);
3566 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
3567 if (ev->eventfd == eventfd) {
3568 list_del(&ev->list);
3573 spin_unlock(&memcg_oom_lock);
3576 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
3578 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
3580 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
3581 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
3585 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
3586 struct cftype *cft, u64 val)
3588 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3590 /* cannot set to root cgroup and only 0 and 1 are allowed */
3591 if (!css->parent || !((val == 0) || (val == 1)))
3594 memcg->oom_kill_disable = val;
3596 memcg_oom_recover(memcg);
3601 #ifdef CONFIG_CGROUP_WRITEBACK
3603 struct list_head *mem_cgroup_cgwb_list(struct mem_cgroup *memcg)
3605 return &memcg->cgwb_list;
3608 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
3610 return wb_domain_init(&memcg->cgwb_domain, gfp);
3613 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
3615 wb_domain_exit(&memcg->cgwb_domain);
3618 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
3620 wb_domain_size_changed(&memcg->cgwb_domain);
3623 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
3625 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
3627 if (!memcg->css.parent)
3630 return &memcg->cgwb_domain;
3634 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
3635 * @wb: bdi_writeback in question
3636 * @pfilepages: out parameter for number of file pages
3637 * @pheadroom: out parameter for number of allocatable pages according to memcg
3638 * @pdirty: out parameter for number of dirty pages
3639 * @pwriteback: out parameter for number of pages under writeback
3641 * Determine the numbers of file, headroom, dirty, and writeback pages in
3642 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
3643 * is a bit more involved.
3645 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
3646 * headroom is calculated as the lowest headroom of itself and the
3647 * ancestors. Note that this doesn't consider the actual amount of
3648 * available memory in the system. The caller should further cap
3649 * *@pheadroom accordingly.
3651 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
3652 unsigned long *pheadroom, unsigned long *pdirty,
3653 unsigned long *pwriteback)
3655 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
3656 struct mem_cgroup *parent;
3658 *pdirty = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_DIRTY);
3660 /* this should eventually include NR_UNSTABLE_NFS */
3661 *pwriteback = mem_cgroup_read_stat(memcg, MEM_CGROUP_STAT_WRITEBACK);
3662 *pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
3663 (1 << LRU_ACTIVE_FILE));
3664 *pheadroom = PAGE_COUNTER_MAX;
3666 while ((parent = parent_mem_cgroup(memcg))) {
3667 unsigned long ceiling = min(memcg->memory.limit, memcg->high);
3668 unsigned long used = page_counter_read(&memcg->memory);
3670 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
3675 #else /* CONFIG_CGROUP_WRITEBACK */
3677 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
3682 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
3686 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
3690 #endif /* CONFIG_CGROUP_WRITEBACK */
3693 * DO NOT USE IN NEW FILES.
3695 * "cgroup.event_control" implementation.
3697 * This is way over-engineered. It tries to support fully configurable
3698 * events for each user. Such level of flexibility is completely
3699 * unnecessary especially in the light of the planned unified hierarchy.
3701 * Please deprecate this and replace with something simpler if at all
3706 * Unregister event and free resources.
3708 * Gets called from workqueue.
3710 static void memcg_event_remove(struct work_struct *work)
3712 struct mem_cgroup_event *event =
3713 container_of(work, struct mem_cgroup_event, remove);
3714 struct mem_cgroup *memcg = event->memcg;
3716 remove_wait_queue(event->wqh, &event->wait);
3718 event->unregister_event(memcg, event->eventfd);
3720 /* Notify userspace the event is going away. */
3721 eventfd_signal(event->eventfd, 1);
3723 eventfd_ctx_put(event->eventfd);
3725 css_put(&memcg->css);
3729 * Gets called on POLLHUP on eventfd when user closes it.
3731 * Called with wqh->lock held and interrupts disabled.
3733 static int memcg_event_wake(wait_queue_t *wait, unsigned mode,
3734 int sync, void *key)
3736 struct mem_cgroup_event *event =
3737 container_of(wait, struct mem_cgroup_event, wait);
3738 struct mem_cgroup *memcg = event->memcg;
3739 unsigned long flags = (unsigned long)key;
3741 if (flags & POLLHUP) {
3743 * If the event has been detached at cgroup removal, we
3744 * can simply return knowing the other side will cleanup
3747 * We can't race against event freeing since the other
3748 * side will require wqh->lock via remove_wait_queue(),
3751 spin_lock(&memcg->event_list_lock);
3752 if (!list_empty(&event->list)) {
3753 list_del_init(&event->list);
3755 * We are in atomic context, but cgroup_event_remove()
3756 * may sleep, so we have to call it in workqueue.
3758 schedule_work(&event->remove);
3760 spin_unlock(&memcg->event_list_lock);
3766 static void memcg_event_ptable_queue_proc(struct file *file,
3767 wait_queue_head_t *wqh, poll_table *pt)
3769 struct mem_cgroup_event *event =
3770 container_of(pt, struct mem_cgroup_event, pt);
3773 add_wait_queue(wqh, &event->wait);
3777 * DO NOT USE IN NEW FILES.
3779 * Parse input and register new cgroup event handler.
3781 * Input must be in format '<event_fd> <control_fd> <args>'.
3782 * Interpretation of args is defined by control file implementation.
3784 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
3785 char *buf, size_t nbytes, loff_t off)
3787 struct cgroup_subsys_state *css = of_css(of);
3788 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3789 struct mem_cgroup_event *event;
3790 struct cgroup_subsys_state *cfile_css;
3791 unsigned int efd, cfd;
3798 buf = strstrip(buf);
3800 efd = simple_strtoul(buf, &endp, 10);
3805 cfd = simple_strtoul(buf, &endp, 10);
3806 if ((*endp != ' ') && (*endp != '\0'))
3810 event = kzalloc(sizeof(*event), GFP_KERNEL);
3814 event->memcg = memcg;
3815 INIT_LIST_HEAD(&event->list);
3816 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
3817 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
3818 INIT_WORK(&event->remove, memcg_event_remove);
3826 event->eventfd = eventfd_ctx_fileget(efile.file);
3827 if (IS_ERR(event->eventfd)) {
3828 ret = PTR_ERR(event->eventfd);
3835 goto out_put_eventfd;
3838 /* the process need read permission on control file */
3839 /* AV: shouldn't we check that it's been opened for read instead? */
3840 ret = inode_permission(file_inode(cfile.file), MAY_READ);
3845 * Determine the event callbacks and set them in @event. This used
3846 * to be done via struct cftype but cgroup core no longer knows
3847 * about these events. The following is crude but the whole thing
3848 * is for compatibility anyway.
3850 * DO NOT ADD NEW FILES.
3852 name = cfile.file->f_path.dentry->d_name.name;
3854 if (!strcmp(name, "memory.usage_in_bytes")) {
3855 event->register_event = mem_cgroup_usage_register_event;
3856 event->unregister_event = mem_cgroup_usage_unregister_event;
3857 } else if (!strcmp(name, "memory.oom_control")) {
3858 event->register_event = mem_cgroup_oom_register_event;
3859 event->unregister_event = mem_cgroup_oom_unregister_event;
3860 } else if (!strcmp(name, "memory.pressure_level")) {
3861 event->register_event = vmpressure_register_event;
3862 event->unregister_event = vmpressure_unregister_event;
3863 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
3864 event->register_event = memsw_cgroup_usage_register_event;
3865 event->unregister_event = memsw_cgroup_usage_unregister_event;
3872 * Verify @cfile should belong to @css. Also, remaining events are
3873 * automatically removed on cgroup destruction but the removal is
3874 * asynchronous, so take an extra ref on @css.
3876 cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
3877 &memory_cgrp_subsys);
3879 if (IS_ERR(cfile_css))
3881 if (cfile_css != css) {
3886 ret = event->register_event(memcg, event->eventfd, buf);
3890 efile.file->f_op->poll(efile.file, &event->pt);
3892 spin_lock(&memcg->event_list_lock);
3893 list_add(&event->list, &memcg->event_list);
3894 spin_unlock(&memcg->event_list_lock);
3906 eventfd_ctx_put(event->eventfd);
3915 static struct cftype mem_cgroup_legacy_files[] = {
3917 .name = "usage_in_bytes",
3918 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
3919 .read_u64 = mem_cgroup_read_u64,
3922 .name = "max_usage_in_bytes",
3923 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
3924 .write = mem_cgroup_reset,
3925 .read_u64 = mem_cgroup_read_u64,
3928 .name = "limit_in_bytes",
3929 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
3930 .write = mem_cgroup_write,
3931 .read_u64 = mem_cgroup_read_u64,
3934 .name = "soft_limit_in_bytes",
3935 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
3936 .write = mem_cgroup_write,
3937 .read_u64 = mem_cgroup_read_u64,
3941 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
3942 .write = mem_cgroup_reset,
3943 .read_u64 = mem_cgroup_read_u64,
3947 .seq_show = memcg_stat_show,
3950 .name = "force_empty",
3951 .write = mem_cgroup_force_empty_write,
3954 .name = "use_hierarchy",
3955 .write_u64 = mem_cgroup_hierarchy_write,
3956 .read_u64 = mem_cgroup_hierarchy_read,
3959 .name = "cgroup.event_control", /* XXX: for compat */
3960 .write = memcg_write_event_control,
3961 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
3964 .name = "swappiness",
3965 .read_u64 = mem_cgroup_swappiness_read,
3966 .write_u64 = mem_cgroup_swappiness_write,
3969 .name = "move_charge_at_immigrate",
3970 .read_u64 = mem_cgroup_move_charge_read,
3971 .write_u64 = mem_cgroup_move_charge_write,
3974 .name = "oom_control",
3975 .seq_show = mem_cgroup_oom_control_read,
3976 .write_u64 = mem_cgroup_oom_control_write,
3977 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
3980 .name = "pressure_level",
3984 .name = "numa_stat",
3985 .seq_show = memcg_numa_stat_show,
3989 .name = "kmem.limit_in_bytes",
3990 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
3991 .write = mem_cgroup_write,
3992 .read_u64 = mem_cgroup_read_u64,
3995 .name = "kmem.usage_in_bytes",
3996 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
3997 .read_u64 = mem_cgroup_read_u64,
4000 .name = "kmem.failcnt",
4001 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4002 .write = mem_cgroup_reset,
4003 .read_u64 = mem_cgroup_read_u64,
4006 .name = "kmem.max_usage_in_bytes",
4007 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4008 .write = mem_cgroup_reset,
4009 .read_u64 = mem_cgroup_read_u64,
4011 #ifdef CONFIG_SLABINFO
4013 .name = "kmem.slabinfo",
4014 .seq_start = slab_start,
4015 .seq_next = slab_next,
4016 .seq_stop = slab_stop,
4017 .seq_show = memcg_slab_show,
4021 .name = "kmem.tcp.limit_in_bytes",
4022 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
4023 .write = mem_cgroup_write,
4024 .read_u64 = mem_cgroup_read_u64,
4027 .name = "kmem.tcp.usage_in_bytes",
4028 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
4029 .read_u64 = mem_cgroup_read_u64,
4032 .name = "kmem.tcp.failcnt",
4033 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
4034 .write = mem_cgroup_reset,
4035 .read_u64 = mem_cgroup_read_u64,
4038 .name = "kmem.tcp.max_usage_in_bytes",
4039 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
4040 .write = mem_cgroup_reset,
4041 .read_u64 = mem_cgroup_read_u64,
4043 { }, /* terminate */
4047 * Private memory cgroup IDR
4049 * Swap-out records and page cache shadow entries need to store memcg
4050 * references in constrained space, so we maintain an ID space that is
4051 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4052 * memory-controlled cgroups to 64k.
4054 * However, there usually are many references to the oflline CSS after
4055 * the cgroup has been destroyed, such as page cache or reclaimable
4056 * slab objects, that don't need to hang on to the ID. We want to keep
4057 * those dead CSS from occupying IDs, or we might quickly exhaust the
4058 * relatively small ID space and prevent the creation of new cgroups
4059 * even when there are much fewer than 64k cgroups - possibly none.
4061 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4062 * be freed and recycled when it's no longer needed, which is usually
4063 * when the CSS is offlined.
4065 * The only exception to that are records of swapped out tmpfs/shmem
4066 * pages that need to be attributed to live ancestors on swapin. But
4067 * those references are manageable from userspace.
4070 static DEFINE_IDR(mem_cgroup_idr);
4072 static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
4074 VM_BUG_ON(atomic_read(&memcg->id.ref) <= 0);
4075 atomic_add(n, &memcg->id.ref);
4078 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
4080 VM_BUG_ON(atomic_read(&memcg->id.ref) < n);
4081 if (atomic_sub_and_test(n, &memcg->id.ref)) {
4082 idr_remove(&mem_cgroup_idr, memcg->id.id);
4085 /* Memcg ID pins CSS */
4086 css_put(&memcg->css);
4090 static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
4092 mem_cgroup_id_get_many(memcg, 1);
4095 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
4097 mem_cgroup_id_put_many(memcg, 1);
4101 * mem_cgroup_from_id - look up a memcg from a memcg id
4102 * @id: the memcg id to look up
4104 * Caller must hold rcu_read_lock().
4106 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
4108 WARN_ON_ONCE(!rcu_read_lock_held());
4109 return idr_find(&mem_cgroup_idr, id);
4112 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4114 struct mem_cgroup_per_node *pn;
4117 * This routine is called against possible nodes.
4118 * But it's BUG to call kmalloc() against offline node.
4120 * TODO: this routine can waste much memory for nodes which will
4121 * never be onlined. It's better to use memory hotplug callback
4124 if (!node_state(node, N_NORMAL_MEMORY))
4126 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4130 lruvec_init(&pn->lruvec);
4131 pn->usage_in_excess = 0;
4132 pn->on_tree = false;
4135 memcg->nodeinfo[node] = pn;
4139 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4141 kfree(memcg->nodeinfo[node]);
4144 static void mem_cgroup_free(struct mem_cgroup *memcg)
4148 memcg_wb_domain_exit(memcg);
4150 free_mem_cgroup_per_node_info(memcg, node);
4151 free_percpu(memcg->stat);
4155 static struct mem_cgroup *mem_cgroup_alloc(void)
4157 struct mem_cgroup *memcg;
4161 size = sizeof(struct mem_cgroup);
4162 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
4164 memcg = kzalloc(size, GFP_KERNEL);
4168 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
4169 1, MEM_CGROUP_ID_MAX,
4171 if (memcg->id.id < 0)
4174 memcg->stat = alloc_percpu(struct mem_cgroup_stat_cpu);
4179 if (alloc_mem_cgroup_per_node_info(memcg, node))
4182 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
4185 INIT_WORK(&memcg->high_work, high_work_func);
4186 memcg->last_scanned_node = MAX_NUMNODES;
4187 INIT_LIST_HEAD(&memcg->oom_notify);
4188 mutex_init(&memcg->thresholds_lock);
4189 spin_lock_init(&memcg->move_lock);
4190 vmpressure_init(&memcg->vmpressure);
4191 INIT_LIST_HEAD(&memcg->event_list);
4192 spin_lock_init(&memcg->event_list_lock);
4193 memcg->socket_pressure = jiffies;
4195 memcg->kmemcg_id = -1;
4197 #ifdef CONFIG_CGROUP_WRITEBACK
4198 INIT_LIST_HEAD(&memcg->cgwb_list);
4200 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
4203 if (memcg->id.id > 0)
4204 idr_remove(&mem_cgroup_idr, memcg->id.id);
4205 mem_cgroup_free(memcg);
4209 static struct cgroup_subsys_state * __ref
4210 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
4212 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
4213 struct mem_cgroup *memcg;
4214 long error = -ENOMEM;
4216 memcg = mem_cgroup_alloc();
4218 return ERR_PTR(error);
4220 memcg->high = PAGE_COUNTER_MAX;
4221 memcg->soft_limit = PAGE_COUNTER_MAX;
4223 memcg->swappiness = mem_cgroup_swappiness(parent);
4224 memcg->oom_kill_disable = parent->oom_kill_disable;
4226 if (parent && parent->use_hierarchy) {
4227 memcg->use_hierarchy = true;
4228 page_counter_init(&memcg->memory, &parent->memory);
4229 page_counter_init(&memcg->swap, &parent->swap);
4230 page_counter_init(&memcg->memsw, &parent->memsw);
4231 page_counter_init(&memcg->kmem, &parent->kmem);
4232 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
4234 page_counter_init(&memcg->memory, NULL);
4235 page_counter_init(&memcg->swap, NULL);
4236 page_counter_init(&memcg->memsw, NULL);
4237 page_counter_init(&memcg->kmem, NULL);
4238 page_counter_init(&memcg->tcpmem, NULL);
4240 * Deeper hierachy with use_hierarchy == false doesn't make
4241 * much sense so let cgroup subsystem know about this
4242 * unfortunate state in our controller.
4244 if (parent != root_mem_cgroup)
4245 memory_cgrp_subsys.broken_hierarchy = true;
4248 /* The following stuff does not apply to the root */
4250 root_mem_cgroup = memcg;
4254 error = memcg_online_kmem(memcg);
4258 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
4259 static_branch_inc(&memcg_sockets_enabled_key);
4263 mem_cgroup_free(memcg);
4264 return ERR_PTR(-ENOMEM);
4267 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
4269 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4271 /* Online state pins memcg ID, memcg ID pins CSS */
4272 atomic_set(&memcg->id.ref, 1);
4277 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
4279 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4280 struct mem_cgroup_event *event, *tmp;
4283 * Unregister events and notify userspace.
4284 * Notify userspace about cgroup removing only after rmdir of cgroup
4285 * directory to avoid race between userspace and kernelspace.
4287 spin_lock(&memcg->event_list_lock);
4288 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
4289 list_del_init(&event->list);
4290 schedule_work(&event->remove);
4292 spin_unlock(&memcg->event_list_lock);
4294 memcg_offline_kmem(memcg);
4295 wb_memcg_offline(memcg);
4297 mem_cgroup_id_put(memcg);
4300 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
4302 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4304 invalidate_reclaim_iterators(memcg);
4307 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
4309 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4311 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
4312 static_branch_dec(&memcg_sockets_enabled_key);
4314 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
4315 static_branch_dec(&memcg_sockets_enabled_key);
4317 vmpressure_cleanup(&memcg->vmpressure);
4318 cancel_work_sync(&memcg->high_work);
4319 mem_cgroup_remove_from_trees(memcg);
4320 memcg_free_kmem(memcg);
4321 mem_cgroup_free(memcg);
4325 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4326 * @css: the target css
4328 * Reset the states of the mem_cgroup associated with @css. This is
4329 * invoked when the userland requests disabling on the default hierarchy
4330 * but the memcg is pinned through dependency. The memcg should stop
4331 * applying policies and should revert to the vanilla state as it may be
4332 * made visible again.
4334 * The current implementation only resets the essential configurations.
4335 * This needs to be expanded to cover all the visible parts.
4337 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
4339 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4341 page_counter_limit(&memcg->memory, PAGE_COUNTER_MAX);
4342 page_counter_limit(&memcg->swap, PAGE_COUNTER_MAX);
4343 page_counter_limit(&memcg->memsw, PAGE_COUNTER_MAX);
4344 page_counter_limit(&memcg->kmem, PAGE_COUNTER_MAX);
4345 page_counter_limit(&memcg->tcpmem, PAGE_COUNTER_MAX);
4347 memcg->high = PAGE_COUNTER_MAX;
4348 memcg->soft_limit = PAGE_COUNTER_MAX;
4349 memcg_wb_domain_size_changed(memcg);
4353 /* Handlers for move charge at task migration. */
4354 static int mem_cgroup_do_precharge(unsigned long count)
4358 /* Try a single bulk charge without reclaim first, kswapd may wake */
4359 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
4361 mc.precharge += count;
4365 /* Try charges one by one with reclaim */
4367 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
4381 enum mc_target_type {
4387 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4388 unsigned long addr, pte_t ptent)
4390 struct page *page = vm_normal_page(vma, addr, ptent);
4392 if (!page || !page_mapped(page))
4394 if (PageAnon(page)) {
4395 if (!(mc.flags & MOVE_ANON))
4398 if (!(mc.flags & MOVE_FILE))
4401 if (!get_page_unless_zero(page))
4408 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4409 pte_t ptent, swp_entry_t *entry)
4411 struct page *page = NULL;
4412 swp_entry_t ent = pte_to_swp_entry(ptent);
4414 if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent))
4417 * Because lookup_swap_cache() updates some statistics counter,
4418 * we call find_get_page() with swapper_space directly.
4420 page = find_get_page(swap_address_space(ent), swp_offset(ent));
4421 if (do_memsw_account())
4422 entry->val = ent.val;
4427 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4428 pte_t ptent, swp_entry_t *entry)
4434 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4435 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4437 struct page *page = NULL;
4438 struct address_space *mapping;
4441 if (!vma->vm_file) /* anonymous vma */
4443 if (!(mc.flags & MOVE_FILE))
4446 mapping = vma->vm_file->f_mapping;
4447 pgoff = linear_page_index(vma, addr);
4449 /* page is moved even if it's not RSS of this task(page-faulted). */
4451 /* shmem/tmpfs may report page out on swap: account for that too. */
4452 if (shmem_mapping(mapping)) {
4453 page = find_get_entry(mapping, pgoff);
4454 if (radix_tree_exceptional_entry(page)) {
4455 swp_entry_t swp = radix_to_swp_entry(page);
4456 if (do_memsw_account())
4458 page = find_get_page(swap_address_space(swp),
4462 page = find_get_page(mapping, pgoff);
4464 page = find_get_page(mapping, pgoff);
4470 * mem_cgroup_move_account - move account of the page
4472 * @compound: charge the page as compound or small page
4473 * @from: mem_cgroup which the page is moved from.
4474 * @to: mem_cgroup which the page is moved to. @from != @to.
4476 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
4478 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
4481 static int mem_cgroup_move_account(struct page *page,
4483 struct mem_cgroup *from,
4484 struct mem_cgroup *to)
4486 unsigned long flags;
4487 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
4491 VM_BUG_ON(from == to);
4492 VM_BUG_ON_PAGE(PageLRU(page), page);
4493 VM_BUG_ON(compound && !PageTransHuge(page));
4496 * Prevent mem_cgroup_migrate() from looking at
4497 * page->mem_cgroup of its source page while we change it.
4500 if (!trylock_page(page))
4504 if (page->mem_cgroup != from)
4507 anon = PageAnon(page);
4509 spin_lock_irqsave(&from->move_lock, flags);
4511 if (!anon && page_mapped(page)) {
4512 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
4514 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED],
4519 * move_lock grabbed above and caller set from->moving_account, so
4520 * mem_cgroup_update_page_stat() will serialize updates to PageDirty.
4521 * So mapping should be stable for dirty pages.
4523 if (!anon && PageDirty(page)) {
4524 struct address_space *mapping = page_mapping(page);
4526 if (mapping_cap_account_dirty(mapping)) {
4527 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_DIRTY],
4529 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_DIRTY],
4534 if (PageWriteback(page)) {
4535 __this_cpu_sub(from->stat->count[MEM_CGROUP_STAT_WRITEBACK],
4537 __this_cpu_add(to->stat->count[MEM_CGROUP_STAT_WRITEBACK],
4542 * It is safe to change page->mem_cgroup here because the page
4543 * is referenced, charged, and isolated - we can't race with
4544 * uncharging, charging, migration, or LRU putback.
4547 /* caller should have done css_get */
4548 page->mem_cgroup = to;
4549 spin_unlock_irqrestore(&from->move_lock, flags);
4553 local_irq_disable();
4554 mem_cgroup_charge_statistics(to, page, compound, nr_pages);
4555 memcg_check_events(to, page);
4556 mem_cgroup_charge_statistics(from, page, compound, -nr_pages);
4557 memcg_check_events(from, page);
4566 * get_mctgt_type - get target type of moving charge
4567 * @vma: the vma the pte to be checked belongs
4568 * @addr: the address corresponding to the pte to be checked
4569 * @ptent: the pte to be checked
4570 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4573 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4574 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4575 * move charge. if @target is not NULL, the page is stored in target->page
4576 * with extra refcnt got(Callers should handle it).
4577 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4578 * target for charge migration. if @target is not NULL, the entry is stored
4581 * Called with pte lock held.
4584 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
4585 unsigned long addr, pte_t ptent, union mc_target *target)
4587 struct page *page = NULL;
4588 enum mc_target_type ret = MC_TARGET_NONE;
4589 swp_entry_t ent = { .val = 0 };
4591 if (pte_present(ptent))
4592 page = mc_handle_present_pte(vma, addr, ptent);
4593 else if (is_swap_pte(ptent))
4594 page = mc_handle_swap_pte(vma, ptent, &ent);
4595 else if (pte_none(ptent))
4596 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4598 if (!page && !ent.val)
4602 * Do only loose check w/o serialization.
4603 * mem_cgroup_move_account() checks the page is valid or
4604 * not under LRU exclusion.
4606 if (page->mem_cgroup == mc.from) {
4607 ret = MC_TARGET_PAGE;
4609 target->page = page;
4611 if (!ret || !target)
4614 /* There is a swap entry and a page doesn't exist or isn't charged */
4615 if (ent.val && !ret &&
4616 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
4617 ret = MC_TARGET_SWAP;
4624 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4626 * We don't consider swapping or file mapped pages because THP does not
4627 * support them for now.
4628 * Caller should make sure that pmd_trans_huge(pmd) is true.
4630 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
4631 unsigned long addr, pmd_t pmd, union mc_target *target)
4633 struct page *page = NULL;
4634 enum mc_target_type ret = MC_TARGET_NONE;
4636 page = pmd_page(pmd);
4637 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
4638 if (!(mc.flags & MOVE_ANON))
4640 if (page->mem_cgroup == mc.from) {
4641 ret = MC_TARGET_PAGE;
4644 target->page = page;
4650 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
4651 unsigned long addr, pmd_t pmd, union mc_target *target)
4653 return MC_TARGET_NONE;
4657 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4658 unsigned long addr, unsigned long end,
4659 struct mm_walk *walk)
4661 struct vm_area_struct *vma = walk->vma;
4665 ptl = pmd_trans_huge_lock(pmd, vma);
4667 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
4668 mc.precharge += HPAGE_PMD_NR;
4673 if (pmd_trans_unstable(pmd))
4675 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4676 for (; addr != end; pte++, addr += PAGE_SIZE)
4677 if (get_mctgt_type(vma, addr, *pte, NULL))
4678 mc.precharge++; /* increment precharge temporarily */
4679 pte_unmap_unlock(pte - 1, ptl);
4685 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
4687 unsigned long precharge;
4689 struct mm_walk mem_cgroup_count_precharge_walk = {
4690 .pmd_entry = mem_cgroup_count_precharge_pte_range,
4693 down_read(&mm->mmap_sem);
4694 walk_page_range(0, mm->highest_vm_end,
4695 &mem_cgroup_count_precharge_walk);
4696 up_read(&mm->mmap_sem);
4698 precharge = mc.precharge;
4704 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
4706 unsigned long precharge = mem_cgroup_count_precharge(mm);
4708 VM_BUG_ON(mc.moving_task);
4709 mc.moving_task = current;
4710 return mem_cgroup_do_precharge(precharge);
4713 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
4714 static void __mem_cgroup_clear_mc(void)
4716 struct mem_cgroup *from = mc.from;
4717 struct mem_cgroup *to = mc.to;
4719 /* we must uncharge all the leftover precharges from mc.to */
4721 cancel_charge(mc.to, mc.precharge);
4725 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
4726 * we must uncharge here.
4728 if (mc.moved_charge) {
4729 cancel_charge(mc.from, mc.moved_charge);
4730 mc.moved_charge = 0;
4732 /* we must fixup refcnts and charges */
4733 if (mc.moved_swap) {
4734 /* uncharge swap account from the old cgroup */
4735 if (!mem_cgroup_is_root(mc.from))
4736 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
4738 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
4741 * we charged both to->memory and to->memsw, so we
4742 * should uncharge to->memory.
4744 if (!mem_cgroup_is_root(mc.to))
4745 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
4747 mem_cgroup_id_get_many(mc.to, mc.moved_swap);
4748 css_put_many(&mc.to->css, mc.moved_swap);
4752 memcg_oom_recover(from);
4753 memcg_oom_recover(to);
4754 wake_up_all(&mc.waitq);
4757 static void mem_cgroup_clear_mc(void)
4759 struct mm_struct *mm = mc.mm;
4762 * we must clear moving_task before waking up waiters at the end of
4765 mc.moving_task = NULL;
4766 __mem_cgroup_clear_mc();
4767 spin_lock(&mc.lock);
4771 spin_unlock(&mc.lock);
4776 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
4778 struct cgroup_subsys_state *css;
4779 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
4780 struct mem_cgroup *from;
4781 struct task_struct *leader, *p;
4782 struct mm_struct *mm;
4783 unsigned long move_flags;
4786 /* charge immigration isn't supported on the default hierarchy */
4787 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
4791 * Multi-process migrations only happen on the default hierarchy
4792 * where charge immigration is not used. Perform charge
4793 * immigration if @tset contains a leader and whine if there are
4797 cgroup_taskset_for_each_leader(leader, css, tset) {
4800 memcg = mem_cgroup_from_css(css);
4806 * We are now commited to this value whatever it is. Changes in this
4807 * tunable will only affect upcoming migrations, not the current one.
4808 * So we need to save it, and keep it going.
4810 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
4814 from = mem_cgroup_from_task(p);
4816 VM_BUG_ON(from == memcg);
4818 mm = get_task_mm(p);
4821 /* We move charges only when we move a owner of the mm */
4822 if (mm->owner == p) {
4825 VM_BUG_ON(mc.precharge);
4826 VM_BUG_ON(mc.moved_charge);
4827 VM_BUG_ON(mc.moved_swap);
4829 spin_lock(&mc.lock);
4833 mc.flags = move_flags;
4834 spin_unlock(&mc.lock);
4835 /* We set mc.moving_task later */
4837 ret = mem_cgroup_precharge_mc(mm);
4839 mem_cgroup_clear_mc();
4846 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
4849 mem_cgroup_clear_mc();
4852 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
4853 unsigned long addr, unsigned long end,
4854 struct mm_walk *walk)
4857 struct vm_area_struct *vma = walk->vma;
4860 enum mc_target_type target_type;
4861 union mc_target target;
4864 ptl = pmd_trans_huge_lock(pmd, vma);
4866 if (mc.precharge < HPAGE_PMD_NR) {
4870 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
4871 if (target_type == MC_TARGET_PAGE) {
4873 if (!isolate_lru_page(page)) {
4874 if (!mem_cgroup_move_account(page, true,
4876 mc.precharge -= HPAGE_PMD_NR;
4877 mc.moved_charge += HPAGE_PMD_NR;
4879 putback_lru_page(page);
4887 if (pmd_trans_unstable(pmd))
4890 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4891 for (; addr != end; addr += PAGE_SIZE) {
4892 pte_t ptent = *(pte++);
4898 switch (get_mctgt_type(vma, addr, ptent, &target)) {
4899 case MC_TARGET_PAGE:
4902 * We can have a part of the split pmd here. Moving it
4903 * can be done but it would be too convoluted so simply
4904 * ignore such a partial THP and keep it in original
4905 * memcg. There should be somebody mapping the head.
4907 if (PageTransCompound(page))
4909 if (isolate_lru_page(page))
4911 if (!mem_cgroup_move_account(page, false,
4914 /* we uncharge from mc.from later. */
4917 putback_lru_page(page);
4918 put: /* get_mctgt_type() gets the page */
4921 case MC_TARGET_SWAP:
4923 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
4925 /* we fixup refcnts and charges later. */
4933 pte_unmap_unlock(pte - 1, ptl);
4938 * We have consumed all precharges we got in can_attach().
4939 * We try charge one by one, but don't do any additional
4940 * charges to mc.to if we have failed in charge once in attach()
4943 ret = mem_cgroup_do_precharge(1);
4951 static void mem_cgroup_move_charge(void)
4953 struct mm_walk mem_cgroup_move_charge_walk = {
4954 .pmd_entry = mem_cgroup_move_charge_pte_range,
4958 lru_add_drain_all();
4960 * Signal lock_page_memcg() to take the memcg's move_lock
4961 * while we're moving its pages to another memcg. Then wait
4962 * for already started RCU-only updates to finish.
4964 atomic_inc(&mc.from->moving_account);
4967 if (unlikely(!down_read_trylock(&mc.mm->mmap_sem))) {
4969 * Someone who are holding the mmap_sem might be waiting in
4970 * waitq. So we cancel all extra charges, wake up all waiters,
4971 * and retry. Because we cancel precharges, we might not be able
4972 * to move enough charges, but moving charge is a best-effort
4973 * feature anyway, so it wouldn't be a big problem.
4975 __mem_cgroup_clear_mc();
4980 * When we have consumed all precharges and failed in doing
4981 * additional charge, the page walk just aborts.
4983 walk_page_range(0, mc.mm->highest_vm_end, &mem_cgroup_move_charge_walk);
4985 up_read(&mc.mm->mmap_sem);
4986 atomic_dec(&mc.from->moving_account);
4989 static void mem_cgroup_move_task(void)
4992 mem_cgroup_move_charge();
4993 mem_cgroup_clear_mc();
4996 #else /* !CONFIG_MMU */
4997 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5001 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
5004 static void mem_cgroup_move_task(void)
5010 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5011 * to verify whether we're attached to the default hierarchy on each mount
5014 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
5017 * use_hierarchy is forced on the default hierarchy. cgroup core
5018 * guarantees that @root doesn't have any children, so turning it
5019 * on for the root memcg is enough.
5021 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5022 root_mem_cgroup->use_hierarchy = true;
5024 root_mem_cgroup->use_hierarchy = false;
5027 static u64 memory_current_read(struct cgroup_subsys_state *css,
5030 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5032 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
5035 static int memory_low_show(struct seq_file *m, void *v)
5037 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5038 unsigned long low = READ_ONCE(memcg->low);
5040 if (low == PAGE_COUNTER_MAX)
5041 seq_puts(m, "max\n");
5043 seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE);
5048 static ssize_t memory_low_write(struct kernfs_open_file *of,
5049 char *buf, size_t nbytes, loff_t off)
5051 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5055 buf = strstrip(buf);
5056 err = page_counter_memparse(buf, "max", &low);
5065 static int memory_high_show(struct seq_file *m, void *v)
5067 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5068 unsigned long high = READ_ONCE(memcg->high);
5070 if (high == PAGE_COUNTER_MAX)
5071 seq_puts(m, "max\n");
5073 seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE);
5078 static ssize_t memory_high_write(struct kernfs_open_file *of,
5079 char *buf, size_t nbytes, loff_t off)
5081 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5082 unsigned long nr_pages;
5086 buf = strstrip(buf);
5087 err = page_counter_memparse(buf, "max", &high);
5093 nr_pages = page_counter_read(&memcg->memory);
5094 if (nr_pages > high)
5095 try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
5098 memcg_wb_domain_size_changed(memcg);
5102 static int memory_max_show(struct seq_file *m, void *v)
5104 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5105 unsigned long max = READ_ONCE(memcg->memory.limit);
5107 if (max == PAGE_COUNTER_MAX)
5108 seq_puts(m, "max\n");
5110 seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
5115 static ssize_t memory_max_write(struct kernfs_open_file *of,
5116 char *buf, size_t nbytes, loff_t off)
5118 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5119 unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES;
5120 bool drained = false;
5124 buf = strstrip(buf);
5125 err = page_counter_memparse(buf, "max", &max);
5129 xchg(&memcg->memory.limit, max);
5132 unsigned long nr_pages = page_counter_read(&memcg->memory);
5134 if (nr_pages <= max)
5137 if (signal_pending(current)) {
5143 drain_all_stock(memcg);
5149 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
5155 mem_cgroup_events(memcg, MEMCG_OOM, 1);
5156 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
5160 memcg_wb_domain_size_changed(memcg);
5164 static int memory_events_show(struct seq_file *m, void *v)
5166 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5168 seq_printf(m, "low %lu\n", mem_cgroup_read_events(memcg, MEMCG_LOW));
5169 seq_printf(m, "high %lu\n", mem_cgroup_read_events(memcg, MEMCG_HIGH));
5170 seq_printf(m, "max %lu\n", mem_cgroup_read_events(memcg, MEMCG_MAX));
5171 seq_printf(m, "oom %lu\n", mem_cgroup_read_events(memcg, MEMCG_OOM));
5176 static int memory_stat_show(struct seq_file *m, void *v)
5178 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5179 unsigned long stat[MEMCG_NR_STAT];
5180 unsigned long events[MEMCG_NR_EVENTS];
5184 * Provide statistics on the state of the memory subsystem as
5185 * well as cumulative event counters that show past behavior.
5187 * This list is ordered following a combination of these gradients:
5188 * 1) generic big picture -> specifics and details
5189 * 2) reflecting userspace activity -> reflecting kernel heuristics
5191 * Current memory state:
5194 tree_stat(memcg, stat);
5195 tree_events(memcg, events);
5197 seq_printf(m, "anon %llu\n",
5198 (u64)stat[MEM_CGROUP_STAT_RSS] * PAGE_SIZE);
5199 seq_printf(m, "file %llu\n",
5200 (u64)stat[MEM_CGROUP_STAT_CACHE] * PAGE_SIZE);
5201 seq_printf(m, "kernel_stack %llu\n",
5202 (u64)stat[MEMCG_KERNEL_STACK_KB] * 1024);
5203 seq_printf(m, "slab %llu\n",
5204 (u64)(stat[MEMCG_SLAB_RECLAIMABLE] +
5205 stat[MEMCG_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
5206 seq_printf(m, "sock %llu\n",
5207 (u64)stat[MEMCG_SOCK] * PAGE_SIZE);
5209 seq_printf(m, "file_mapped %llu\n",
5210 (u64)stat[MEM_CGROUP_STAT_FILE_MAPPED] * PAGE_SIZE);
5211 seq_printf(m, "file_dirty %llu\n",
5212 (u64)stat[MEM_CGROUP_STAT_DIRTY] * PAGE_SIZE);
5213 seq_printf(m, "file_writeback %llu\n",
5214 (u64)stat[MEM_CGROUP_STAT_WRITEBACK] * PAGE_SIZE);
5216 for (i = 0; i < NR_LRU_LISTS; i++) {
5217 struct mem_cgroup *mi;
5218 unsigned long val = 0;
5220 for_each_mem_cgroup_tree(mi, memcg)
5221 val += mem_cgroup_nr_lru_pages(mi, BIT(i));
5222 seq_printf(m, "%s %llu\n",
5223 mem_cgroup_lru_names[i], (u64)val * PAGE_SIZE);
5226 seq_printf(m, "slab_reclaimable %llu\n",
5227 (u64)stat[MEMCG_SLAB_RECLAIMABLE] * PAGE_SIZE);
5228 seq_printf(m, "slab_unreclaimable %llu\n",
5229 (u64)stat[MEMCG_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
5231 /* Accumulated memory events */
5233 seq_printf(m, "pgfault %lu\n",
5234 events[MEM_CGROUP_EVENTS_PGFAULT]);
5235 seq_printf(m, "pgmajfault %lu\n",
5236 events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
5241 static struct cftype memory_files[] = {
5244 .flags = CFTYPE_NOT_ON_ROOT,
5245 .read_u64 = memory_current_read,
5249 .flags = CFTYPE_NOT_ON_ROOT,
5250 .seq_show = memory_low_show,
5251 .write = memory_low_write,
5255 .flags = CFTYPE_NOT_ON_ROOT,
5256 .seq_show = memory_high_show,
5257 .write = memory_high_write,
5261 .flags = CFTYPE_NOT_ON_ROOT,
5262 .seq_show = memory_max_show,
5263 .write = memory_max_write,
5267 .flags = CFTYPE_NOT_ON_ROOT,
5268 .file_offset = offsetof(struct mem_cgroup, events_file),
5269 .seq_show = memory_events_show,
5273 .flags = CFTYPE_NOT_ON_ROOT,
5274 .seq_show = memory_stat_show,
5279 struct cgroup_subsys memory_cgrp_subsys = {
5280 .css_alloc = mem_cgroup_css_alloc,
5281 .css_online = mem_cgroup_css_online,
5282 .css_offline = mem_cgroup_css_offline,
5283 .css_released = mem_cgroup_css_released,
5284 .css_free = mem_cgroup_css_free,
5285 .css_reset = mem_cgroup_css_reset,
5286 .can_attach = mem_cgroup_can_attach,
5287 .cancel_attach = mem_cgroup_cancel_attach,
5288 .post_attach = mem_cgroup_move_task,
5289 .bind = mem_cgroup_bind,
5290 .dfl_cftypes = memory_files,
5291 .legacy_cftypes = mem_cgroup_legacy_files,
5296 * mem_cgroup_low - check if memory consumption is below the normal range
5297 * @root: the highest ancestor to consider
5298 * @memcg: the memory cgroup to check
5300 * Returns %true if memory consumption of @memcg, and that of all
5301 * configurable ancestors up to @root, is below the normal range.
5303 bool mem_cgroup_low(struct mem_cgroup *root, struct mem_cgroup *memcg)
5305 if (mem_cgroup_disabled())
5309 * The toplevel group doesn't have a configurable range, so
5310 * it's never low when looked at directly, and it is not
5311 * considered an ancestor when assessing the hierarchy.
5314 if (memcg == root_mem_cgroup)
5317 if (page_counter_read(&memcg->memory) >= memcg->low)
5320 while (memcg != root) {
5321 memcg = parent_mem_cgroup(memcg);
5323 if (memcg == root_mem_cgroup)
5326 if (page_counter_read(&memcg->memory) >= memcg->low)
5333 * mem_cgroup_try_charge - try charging a page
5334 * @page: page to charge
5335 * @mm: mm context of the victim
5336 * @gfp_mask: reclaim mode
5337 * @memcgp: charged memcg return
5338 * @compound: charge the page as compound or small page
5340 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5341 * pages according to @gfp_mask if necessary.
5343 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5344 * Otherwise, an error code is returned.
5346 * After page->mapping has been set up, the caller must finalize the
5347 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5348 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5350 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
5351 gfp_t gfp_mask, struct mem_cgroup **memcgp,
5354 struct mem_cgroup *memcg = NULL;
5355 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5358 if (mem_cgroup_disabled())
5361 if (PageSwapCache(page)) {
5363 * Every swap fault against a single page tries to charge the
5364 * page, bail as early as possible. shmem_unuse() encounters
5365 * already charged pages, too. The USED bit is protected by
5366 * the page lock, which serializes swap cache removal, which
5367 * in turn serializes uncharging.
5369 VM_BUG_ON_PAGE(!PageLocked(page), page);
5370 if (page->mem_cgroup)
5373 if (do_swap_account) {
5374 swp_entry_t ent = { .val = page_private(page), };
5375 unsigned short id = lookup_swap_cgroup_id(ent);
5378 memcg = mem_cgroup_from_id(id);
5379 if (memcg && !css_tryget_online(&memcg->css))
5386 memcg = get_mem_cgroup_from_mm(mm);
5388 ret = try_charge(memcg, gfp_mask, nr_pages);
5390 css_put(&memcg->css);
5397 * mem_cgroup_commit_charge - commit a page charge
5398 * @page: page to charge
5399 * @memcg: memcg to charge the page to
5400 * @lrucare: page might be on LRU already
5401 * @compound: charge the page as compound or small page
5403 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5404 * after page->mapping has been set up. This must happen atomically
5405 * as part of the page instantiation, i.e. under the page table lock
5406 * for anonymous pages, under the page lock for page and swap cache.
5408 * In addition, the page must not be on the LRU during the commit, to
5409 * prevent racing with task migration. If it might be, use @lrucare.
5411 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5413 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
5414 bool lrucare, bool compound)
5416 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5418 VM_BUG_ON_PAGE(!page->mapping, page);
5419 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
5421 if (mem_cgroup_disabled())
5424 * Swap faults will attempt to charge the same page multiple
5425 * times. But reuse_swap_page() might have removed the page
5426 * from swapcache already, so we can't check PageSwapCache().
5431 commit_charge(page, memcg, lrucare);
5433 local_irq_disable();
5434 mem_cgroup_charge_statistics(memcg, page, compound, nr_pages);
5435 memcg_check_events(memcg, page);
5438 if (do_memsw_account() && PageSwapCache(page)) {
5439 swp_entry_t entry = { .val = page_private(page) };
5441 * The swap entry might not get freed for a long time,
5442 * let's not wait for it. The page already received a
5443 * memory+swap charge, drop the swap entry duplicate.
5445 mem_cgroup_uncharge_swap(entry);
5450 * mem_cgroup_cancel_charge - cancel a page charge
5451 * @page: page to charge
5452 * @memcg: memcg to charge the page to
5453 * @compound: charge the page as compound or small page
5455 * Cancel a charge transaction started by mem_cgroup_try_charge().
5457 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
5460 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5462 if (mem_cgroup_disabled())
5465 * Swap faults will attempt to charge the same page multiple
5466 * times. But reuse_swap_page() might have removed the page
5467 * from swapcache already, so we can't check PageSwapCache().
5472 cancel_charge(memcg, nr_pages);
5475 static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
5476 unsigned long nr_anon, unsigned long nr_file,
5477 unsigned long nr_huge, unsigned long nr_kmem,
5478 struct page *dummy_page)
5480 unsigned long nr_pages = nr_anon + nr_file + nr_kmem;
5481 unsigned long flags;
5483 if (!mem_cgroup_is_root(memcg)) {
5484 page_counter_uncharge(&memcg->memory, nr_pages);
5485 if (do_memsw_account())
5486 page_counter_uncharge(&memcg->memsw, nr_pages);
5487 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && nr_kmem)
5488 page_counter_uncharge(&memcg->kmem, nr_kmem);
5489 memcg_oom_recover(memcg);
5492 local_irq_save(flags);
5493 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS], nr_anon);
5494 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
5495 __this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
5496 __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
5497 __this_cpu_add(memcg->stat->nr_page_events, nr_pages);
5498 memcg_check_events(memcg, dummy_page);
5499 local_irq_restore(flags);
5501 if (!mem_cgroup_is_root(memcg))
5502 css_put_many(&memcg->css, nr_pages);
5505 static void uncharge_list(struct list_head *page_list)
5507 struct mem_cgroup *memcg = NULL;
5508 unsigned long nr_anon = 0;
5509 unsigned long nr_file = 0;
5510 unsigned long nr_huge = 0;
5511 unsigned long nr_kmem = 0;
5512 unsigned long pgpgout = 0;
5513 struct list_head *next;
5517 * Note that the list can be a single page->lru; hence the
5518 * do-while loop instead of a simple list_for_each_entry().
5520 next = page_list->next;
5522 page = list_entry(next, struct page, lru);
5523 next = page->lru.next;
5525 VM_BUG_ON_PAGE(PageLRU(page), page);
5526 VM_BUG_ON_PAGE(page_count(page), page);
5528 if (!page->mem_cgroup)
5532 * Nobody should be changing or seriously looking at
5533 * page->mem_cgroup at this point, we have fully
5534 * exclusive access to the page.
5537 if (memcg != page->mem_cgroup) {
5539 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5540 nr_huge, nr_kmem, page);
5541 pgpgout = nr_anon = nr_file =
5542 nr_huge = nr_kmem = 0;
5544 memcg = page->mem_cgroup;
5547 if (!PageKmemcg(page)) {
5548 unsigned int nr_pages = 1;
5550 if (PageTransHuge(page)) {
5551 nr_pages <<= compound_order(page);
5552 nr_huge += nr_pages;
5555 nr_anon += nr_pages;
5557 nr_file += nr_pages;
5560 nr_kmem += 1 << compound_order(page);
5561 __ClearPageKmemcg(page);
5564 page->mem_cgroup = NULL;
5565 } while (next != page_list);
5568 uncharge_batch(memcg, pgpgout, nr_anon, nr_file,
5569 nr_huge, nr_kmem, page);
5573 * mem_cgroup_uncharge - uncharge a page
5574 * @page: page to uncharge
5576 * Uncharge a page previously charged with mem_cgroup_try_charge() and
5577 * mem_cgroup_commit_charge().
5579 void mem_cgroup_uncharge(struct page *page)
5581 if (mem_cgroup_disabled())
5584 /* Don't touch page->lru of any random page, pre-check: */
5585 if (!page->mem_cgroup)
5588 INIT_LIST_HEAD(&page->lru);
5589 uncharge_list(&page->lru);
5593 * mem_cgroup_uncharge_list - uncharge a list of page
5594 * @page_list: list of pages to uncharge
5596 * Uncharge a list of pages previously charged with
5597 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
5599 void mem_cgroup_uncharge_list(struct list_head *page_list)
5601 if (mem_cgroup_disabled())
5604 if (!list_empty(page_list))
5605 uncharge_list(page_list);
5609 * mem_cgroup_migrate - charge a page's replacement
5610 * @oldpage: currently circulating page
5611 * @newpage: replacement page
5613 * Charge @newpage as a replacement page for @oldpage. @oldpage will
5614 * be uncharged upon free.
5616 * Both pages must be locked, @newpage->mapping must be set up.
5618 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
5620 struct mem_cgroup *memcg;
5621 unsigned int nr_pages;
5623 unsigned long flags;
5625 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
5626 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
5627 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
5628 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
5631 if (mem_cgroup_disabled())
5634 /* Page cache replacement: new page already charged? */
5635 if (newpage->mem_cgroup)
5638 /* Swapcache readahead pages can get replaced before being charged */
5639 memcg = oldpage->mem_cgroup;
5643 /* Force-charge the new page. The old one will be freed soon */
5644 compound = PageTransHuge(newpage);
5645 nr_pages = compound ? hpage_nr_pages(newpage) : 1;
5647 page_counter_charge(&memcg->memory, nr_pages);
5648 if (do_memsw_account())
5649 page_counter_charge(&memcg->memsw, nr_pages);
5650 css_get_many(&memcg->css, nr_pages);
5652 commit_charge(newpage, memcg, false);
5654 local_irq_save(flags);
5655 mem_cgroup_charge_statistics(memcg, newpage, compound, nr_pages);
5656 memcg_check_events(memcg, newpage);
5657 local_irq_restore(flags);
5660 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
5661 EXPORT_SYMBOL(memcg_sockets_enabled_key);
5663 void mem_cgroup_sk_alloc(struct sock *sk)
5665 struct mem_cgroup *memcg;
5667 if (!mem_cgroup_sockets_enabled)
5671 * Socket cloning can throw us here with sk_memcg already
5672 * filled. It won't however, necessarily happen from
5673 * process context. So the test for root memcg given
5674 * the current task's memcg won't help us in this case.
5676 * Respecting the original socket's memcg is a better
5677 * decision in this case.
5680 BUG_ON(mem_cgroup_is_root(sk->sk_memcg));
5681 css_get(&sk->sk_memcg->css);
5686 memcg = mem_cgroup_from_task(current);
5687 if (memcg == root_mem_cgroup)
5689 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
5691 if (css_tryget_online(&memcg->css))
5692 sk->sk_memcg = memcg;
5697 void mem_cgroup_sk_free(struct sock *sk)
5700 css_put(&sk->sk_memcg->css);
5704 * mem_cgroup_charge_skmem - charge socket memory
5705 * @memcg: memcg to charge
5706 * @nr_pages: number of pages to charge
5708 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
5709 * @memcg's configured limit, %false if the charge had to be forced.
5711 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
5713 gfp_t gfp_mask = GFP_KERNEL;
5715 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
5716 struct page_counter *fail;
5718 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
5719 memcg->tcpmem_pressure = 0;
5722 page_counter_charge(&memcg->tcpmem, nr_pages);
5723 memcg->tcpmem_pressure = 1;
5727 /* Don't block in the packet receive path */
5729 gfp_mask = GFP_NOWAIT;
5731 this_cpu_add(memcg->stat->count[MEMCG_SOCK], nr_pages);
5733 if (try_charge(memcg, gfp_mask, nr_pages) == 0)
5736 try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages);
5741 * mem_cgroup_uncharge_skmem - uncharge socket memory
5742 * @memcg - memcg to uncharge
5743 * @nr_pages - number of pages to uncharge
5745 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
5747 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
5748 page_counter_uncharge(&memcg->tcpmem, nr_pages);
5752 this_cpu_sub(memcg->stat->count[MEMCG_SOCK], nr_pages);
5754 page_counter_uncharge(&memcg->memory, nr_pages);
5755 css_put_many(&memcg->css, nr_pages);
5758 static int __init cgroup_memory(char *s)
5762 while ((token = strsep(&s, ",")) != NULL) {
5765 if (!strcmp(token, "nosocket"))
5766 cgroup_memory_nosocket = true;
5767 if (!strcmp(token, "nokmem"))
5768 cgroup_memory_nokmem = true;
5772 __setup("cgroup.memory=", cgroup_memory);
5775 * subsys_initcall() for memory controller.
5777 * Some parts like hotcpu_notifier() have to be initialized from this context
5778 * because of lock dependencies (cgroup_lock -> cpu hotplug) but basically
5779 * everything that doesn't depend on a specific mem_cgroup structure should
5780 * be initialized from here.
5782 static int __init mem_cgroup_init(void)
5786 hotcpu_notifier(memcg_cpu_hotplug_callback, 0);
5788 for_each_possible_cpu(cpu)
5789 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
5792 for_each_node(node) {
5793 struct mem_cgroup_tree_per_node *rtpn;
5795 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
5796 node_online(node) ? node : NUMA_NO_NODE);
5798 rtpn->rb_root = RB_ROOT;
5799 spin_lock_init(&rtpn->lock);
5800 soft_limit_tree.rb_tree_per_node[node] = rtpn;
5805 subsys_initcall(mem_cgroup_init);
5807 #ifdef CONFIG_MEMCG_SWAP
5808 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
5810 while (!atomic_inc_not_zero(&memcg->id.ref)) {
5812 * The root cgroup cannot be destroyed, so it's refcount must
5815 if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
5819 memcg = parent_mem_cgroup(memcg);
5821 memcg = root_mem_cgroup;
5827 * mem_cgroup_swapout - transfer a memsw charge to swap
5828 * @page: page whose memsw charge to transfer
5829 * @entry: swap entry to move the charge to
5831 * Transfer the memsw charge of @page to @entry.
5833 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
5835 struct mem_cgroup *memcg, *swap_memcg;
5836 unsigned short oldid;
5838 VM_BUG_ON_PAGE(PageLRU(page), page);
5839 VM_BUG_ON_PAGE(page_count(page), page);
5841 if (!do_memsw_account())
5844 memcg = page->mem_cgroup;
5846 /* Readahead page, never charged */
5851 * In case the memcg owning these pages has been offlined and doesn't
5852 * have an ID allocated to it anymore, charge the closest online
5853 * ancestor for the swap instead and transfer the memory+swap charge.
5855 swap_memcg = mem_cgroup_id_get_online(memcg);
5856 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg));
5857 VM_BUG_ON_PAGE(oldid, page);
5858 mem_cgroup_swap_statistics(swap_memcg, true);
5860 page->mem_cgroup = NULL;
5862 if (!mem_cgroup_is_root(memcg))
5863 page_counter_uncharge(&memcg->memory, 1);
5865 if (memcg != swap_memcg) {
5866 if (!mem_cgroup_is_root(swap_memcg))
5867 page_counter_charge(&swap_memcg->memsw, 1);
5868 page_counter_uncharge(&memcg->memsw, 1);
5872 * Interrupts should be disabled here because the caller holds the
5873 * mapping->tree_lock lock which is taken with interrupts-off. It is
5874 * important here to have the interrupts disabled because it is the
5875 * only synchronisation we have for udpating the per-CPU variables.
5877 VM_BUG_ON(!irqs_disabled());
5878 mem_cgroup_charge_statistics(memcg, page, false, -1);
5879 memcg_check_events(memcg, page);
5881 if (!mem_cgroup_is_root(memcg))
5882 css_put(&memcg->css);
5886 * mem_cgroup_try_charge_swap - try charging a swap entry
5887 * @page: page being added to swap
5888 * @entry: swap entry to charge
5890 * Try to charge @entry to the memcg that @page belongs to.
5892 * Returns 0 on success, -ENOMEM on failure.
5894 int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
5896 struct mem_cgroup *memcg;
5897 struct page_counter *counter;
5898 unsigned short oldid;
5900 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !do_swap_account)
5903 memcg = page->mem_cgroup;
5905 /* Readahead page, never charged */
5909 memcg = mem_cgroup_id_get_online(memcg);
5911 if (!mem_cgroup_is_root(memcg) &&
5912 !page_counter_try_charge(&memcg->swap, 1, &counter)) {
5913 mem_cgroup_id_put(memcg);
5917 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
5918 VM_BUG_ON_PAGE(oldid, page);
5919 mem_cgroup_swap_statistics(memcg, true);
5925 * mem_cgroup_uncharge_swap - uncharge a swap entry
5926 * @entry: swap entry to uncharge
5928 * Drop the swap charge associated with @entry.
5930 void mem_cgroup_uncharge_swap(swp_entry_t entry)
5932 struct mem_cgroup *memcg;
5935 if (!do_swap_account)
5938 id = swap_cgroup_record(entry, 0);
5940 memcg = mem_cgroup_from_id(id);
5942 if (!mem_cgroup_is_root(memcg)) {
5943 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5944 page_counter_uncharge(&memcg->swap, 1);
5946 page_counter_uncharge(&memcg->memsw, 1);
5948 mem_cgroup_swap_statistics(memcg, false);
5949 mem_cgroup_id_put(memcg);
5954 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
5956 long nr_swap_pages = get_nr_swap_pages();
5958 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
5959 return nr_swap_pages;
5960 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
5961 nr_swap_pages = min_t(long, nr_swap_pages,
5962 READ_ONCE(memcg->swap.limit) -
5963 page_counter_read(&memcg->swap));
5964 return nr_swap_pages;
5967 bool mem_cgroup_swap_full(struct page *page)
5969 struct mem_cgroup *memcg;
5971 VM_BUG_ON_PAGE(!PageLocked(page), page);
5975 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
5978 memcg = page->mem_cgroup;
5982 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
5983 if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.limit)
5989 /* for remember boot option*/
5990 #ifdef CONFIG_MEMCG_SWAP_ENABLED
5991 static int really_do_swap_account __initdata = 1;
5993 static int really_do_swap_account __initdata;
5996 static int __init enable_swap_account(char *s)
5998 if (!strcmp(s, "1"))
5999 really_do_swap_account = 1;
6000 else if (!strcmp(s, "0"))
6001 really_do_swap_account = 0;
6004 __setup("swapaccount=", enable_swap_account);
6006 static u64 swap_current_read(struct cgroup_subsys_state *css,
6009 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6011 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
6014 static int swap_max_show(struct seq_file *m, void *v)
6016 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
6017 unsigned long max = READ_ONCE(memcg->swap.limit);
6019 if (max == PAGE_COUNTER_MAX)
6020 seq_puts(m, "max\n");
6022 seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
6027 static ssize_t swap_max_write(struct kernfs_open_file *of,
6028 char *buf, size_t nbytes, loff_t off)
6030 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6034 buf = strstrip(buf);
6035 err = page_counter_memparse(buf, "max", &max);
6039 mutex_lock(&memcg_limit_mutex);
6040 err = page_counter_limit(&memcg->swap, max);
6041 mutex_unlock(&memcg_limit_mutex);
6048 static struct cftype swap_files[] = {
6050 .name = "swap.current",
6051 .flags = CFTYPE_NOT_ON_ROOT,
6052 .read_u64 = swap_current_read,
6056 .flags = CFTYPE_NOT_ON_ROOT,
6057 .seq_show = swap_max_show,
6058 .write = swap_max_write,
6063 static struct cftype memsw_cgroup_files[] = {
6065 .name = "memsw.usage_in_bytes",
6066 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
6067 .read_u64 = mem_cgroup_read_u64,
6070 .name = "memsw.max_usage_in_bytes",
6071 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
6072 .write = mem_cgroup_reset,
6073 .read_u64 = mem_cgroup_read_u64,
6076 .name = "memsw.limit_in_bytes",
6077 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
6078 .write = mem_cgroup_write,
6079 .read_u64 = mem_cgroup_read_u64,
6082 .name = "memsw.failcnt",
6083 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
6084 .write = mem_cgroup_reset,
6085 .read_u64 = mem_cgroup_read_u64,
6087 { }, /* terminate */
6090 static int __init mem_cgroup_swap_init(void)
6092 if (!mem_cgroup_disabled() && really_do_swap_account) {
6093 do_swap_account = 1;
6094 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
6096 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
6097 memsw_cgroup_files));
6101 subsys_initcall(mem_cgroup_swap_init);
6103 #endif /* CONFIG_MEMCG_SWAP */