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/sched/mm.h>
39 #include <linux/shmem_fs.h>
40 #include <linux/hugetlb.h>
41 #include <linux/pagemap.h>
42 #include <linux/smp.h>
43 #include <linux/page-flags.h>
44 #include <linux/backing-dev.h>
45 #include <linux/bit_spinlock.h>
46 #include <linux/rcupdate.h>
47 #include <linux/limits.h>
48 #include <linux/export.h>
49 #include <linux/mutex.h>
50 #include <linux/rbtree.h>
51 #include <linux/slab.h>
52 #include <linux/swap.h>
53 #include <linux/swapops.h>
54 #include <linux/spinlock.h>
55 #include <linux/eventfd.h>
56 #include <linux/poll.h>
57 #include <linux/sort.h>
59 #include <linux/seq_file.h>
60 #include <linux/vmpressure.h>
61 #include <linux/mm_inline.h>
62 #include <linux/swap_cgroup.h>
63 #include <linux/cpu.h>
64 #include <linux/oom.h>
65 #include <linux/lockdep.h>
66 #include <linux/file.h>
67 #include <linux/tracehook.h>
73 #include <linux/uaccess.h>
75 #include <trace/events/vmscan.h>
77 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
78 EXPORT_SYMBOL(memory_cgrp_subsys);
80 struct mem_cgroup *root_mem_cgroup __read_mostly;
82 #define MEM_CGROUP_RECLAIM_RETRIES 5
84 /* Socket memory accounting disabled? */
85 static bool cgroup_memory_nosocket;
87 /* Kernel memory accounting disabled? */
88 static bool cgroup_memory_nokmem;
90 /* Whether the swap controller is active */
91 #ifdef CONFIG_MEMCG_SWAP
92 int do_swap_account __read_mostly;
94 #define do_swap_account 0
97 /* Whether legacy memory+swap accounting is active */
98 static bool do_memsw_account(void)
100 return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;
103 static const char *const mem_cgroup_lru_names[] = {
111 #define THRESHOLDS_EVENTS_TARGET 128
112 #define SOFTLIMIT_EVENTS_TARGET 1024
113 #define NUMAINFO_EVENTS_TARGET 1024
116 * Cgroups above their limits are maintained in a RB-Tree, independent of
117 * their hierarchy representation
120 struct mem_cgroup_tree_per_node {
121 struct rb_root rb_root;
122 struct rb_node *rb_rightmost;
126 struct mem_cgroup_tree {
127 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
130 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
133 struct mem_cgroup_eventfd_list {
134 struct list_head list;
135 struct eventfd_ctx *eventfd;
139 * cgroup_event represents events which userspace want to receive.
141 struct mem_cgroup_event {
143 * memcg which the event belongs to.
145 struct mem_cgroup *memcg;
147 * eventfd to signal userspace about the event.
149 struct eventfd_ctx *eventfd;
151 * Each of these stored in a list by the cgroup.
153 struct list_head list;
155 * register_event() callback will be used to add new userspace
156 * waiter for changes related to this event. Use eventfd_signal()
157 * on eventfd to send notification to userspace.
159 int (*register_event)(struct mem_cgroup *memcg,
160 struct eventfd_ctx *eventfd, const char *args);
162 * unregister_event() callback will be called when userspace closes
163 * the eventfd or on cgroup removing. This callback must be set,
164 * if you want provide notification functionality.
166 void (*unregister_event)(struct mem_cgroup *memcg,
167 struct eventfd_ctx *eventfd);
169 * All fields below needed to unregister event when
170 * userspace closes eventfd.
173 wait_queue_head_t *wqh;
174 wait_queue_entry_t wait;
175 struct work_struct remove;
178 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
179 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
181 /* Stuffs for move charges at task migration. */
183 * Types of charges to be moved.
185 #define MOVE_ANON 0x1U
186 #define MOVE_FILE 0x2U
187 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
189 /* "mc" and its members are protected by cgroup_mutex */
190 static struct move_charge_struct {
191 spinlock_t lock; /* for from, to */
192 struct mm_struct *mm;
193 struct mem_cgroup *from;
194 struct mem_cgroup *to;
196 unsigned long precharge;
197 unsigned long moved_charge;
198 unsigned long moved_swap;
199 struct task_struct *moving_task; /* a task moving charges */
200 wait_queue_head_t waitq; /* a waitq for other context */
202 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
203 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
207 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
208 * limit reclaim to prevent infinite loops, if they ever occur.
210 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
211 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
214 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
215 MEM_CGROUP_CHARGE_TYPE_ANON,
216 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
217 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
221 /* for encoding cft->private value on file */
230 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
231 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
232 #define MEMFILE_ATTR(val) ((val) & 0xffff)
233 /* Used for OOM nofiier */
234 #define OOM_CONTROL (0)
237 * Iteration constructs for visiting all cgroups (under a tree). If
238 * loops are exited prematurely (break), mem_cgroup_iter_break() must
239 * be used for reference counting.
241 #define for_each_mem_cgroup_tree(iter, root) \
242 for (iter = mem_cgroup_iter(root, NULL, NULL); \
244 iter = mem_cgroup_iter(root, iter, NULL))
246 #define for_each_mem_cgroup(iter) \
247 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
249 iter = mem_cgroup_iter(NULL, iter, NULL))
251 /* Some nice accessors for the vmpressure. */
252 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
255 memcg = root_mem_cgroup;
256 return &memcg->vmpressure;
259 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
261 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
264 #ifdef CONFIG_MEMCG_KMEM
266 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
267 * The main reason for not using cgroup id for this:
268 * this works better in sparse environments, where we have a lot of memcgs,
269 * but only a few kmem-limited. Or also, if we have, for instance, 200
270 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
271 * 200 entry array for that.
273 * The current size of the caches array is stored in memcg_nr_cache_ids. It
274 * will double each time we have to increase it.
276 static DEFINE_IDA(memcg_cache_ida);
277 int memcg_nr_cache_ids;
279 /* Protects memcg_nr_cache_ids */
280 static DECLARE_RWSEM(memcg_cache_ids_sem);
282 void memcg_get_cache_ids(void)
284 down_read(&memcg_cache_ids_sem);
287 void memcg_put_cache_ids(void)
289 up_read(&memcg_cache_ids_sem);
293 * MIN_SIZE is different than 1, because we would like to avoid going through
294 * the alloc/free process all the time. In a small machine, 4 kmem-limited
295 * cgroups is a reasonable guess. In the future, it could be a parameter or
296 * tunable, but that is strictly not necessary.
298 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
299 * this constant directly from cgroup, but it is understandable that this is
300 * better kept as an internal representation in cgroup.c. In any case, the
301 * cgrp_id space is not getting any smaller, and we don't have to necessarily
302 * increase ours as well if it increases.
304 #define MEMCG_CACHES_MIN_SIZE 4
305 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
308 * A lot of the calls to the cache allocation functions are expected to be
309 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
310 * conditional to this static branch, we'll have to allow modules that does
311 * kmem_cache_alloc and the such to see this symbol as well
313 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
314 EXPORT_SYMBOL(memcg_kmem_enabled_key);
316 struct workqueue_struct *memcg_kmem_cache_wq;
318 static int memcg_shrinker_map_size;
319 static DEFINE_MUTEX(memcg_shrinker_map_mutex);
321 static void memcg_free_shrinker_map_rcu(struct rcu_head *head)
323 kvfree(container_of(head, struct memcg_shrinker_map, rcu));
326 static int memcg_expand_one_shrinker_map(struct mem_cgroup *memcg,
327 int size, int old_size)
329 struct memcg_shrinker_map *new, *old;
332 lockdep_assert_held(&memcg_shrinker_map_mutex);
335 old = rcu_dereference_protected(
336 mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true);
337 /* Not yet online memcg */
341 new = kvmalloc(sizeof(*new) + size, GFP_KERNEL);
345 /* Set all old bits, clear all new bits */
346 memset(new->map, (int)0xff, old_size);
347 memset((void *)new->map + old_size, 0, size - old_size);
349 rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new);
350 call_rcu(&old->rcu, memcg_free_shrinker_map_rcu);
356 static void memcg_free_shrinker_maps(struct mem_cgroup *memcg)
358 struct mem_cgroup_per_node *pn;
359 struct memcg_shrinker_map *map;
362 if (mem_cgroup_is_root(memcg))
366 pn = mem_cgroup_nodeinfo(memcg, nid);
367 map = rcu_dereference_protected(pn->shrinker_map, true);
370 rcu_assign_pointer(pn->shrinker_map, NULL);
374 static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
376 struct memcg_shrinker_map *map;
377 int nid, size, ret = 0;
379 if (mem_cgroup_is_root(memcg))
382 mutex_lock(&memcg_shrinker_map_mutex);
383 size = memcg_shrinker_map_size;
385 map = kvzalloc(sizeof(*map) + size, GFP_KERNEL);
387 memcg_free_shrinker_maps(memcg);
391 rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map);
393 mutex_unlock(&memcg_shrinker_map_mutex);
398 int memcg_expand_shrinker_maps(int new_id)
400 int size, old_size, ret = 0;
401 struct mem_cgroup *memcg;
403 size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
404 old_size = memcg_shrinker_map_size;
405 if (size <= old_size)
408 mutex_lock(&memcg_shrinker_map_mutex);
409 if (!root_mem_cgroup)
412 for_each_mem_cgroup(memcg) {
413 if (mem_cgroup_is_root(memcg))
415 ret = memcg_expand_one_shrinker_map(memcg, size, old_size);
421 memcg_shrinker_map_size = size;
422 mutex_unlock(&memcg_shrinker_map_mutex);
426 void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
428 if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
429 struct memcg_shrinker_map *map;
432 map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map);
433 /* Pairs with smp mb in shrink_slab() */
434 smp_mb__before_atomic();
435 set_bit(shrinker_id, map->map);
440 #else /* CONFIG_MEMCG_KMEM */
441 static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
445 static void memcg_free_shrinker_maps(struct mem_cgroup *memcg) { }
446 #endif /* CONFIG_MEMCG_KMEM */
449 * mem_cgroup_css_from_page - css of the memcg associated with a page
450 * @page: page of interest
452 * If memcg is bound to the default hierarchy, css of the memcg associated
453 * with @page is returned. The returned css remains associated with @page
454 * until it is released.
456 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
459 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
461 struct mem_cgroup *memcg;
463 memcg = page->mem_cgroup;
465 if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
466 memcg = root_mem_cgroup;
472 * page_cgroup_ino - return inode number of the memcg a page is charged to
475 * Look up the closest online ancestor of the memory cgroup @page is charged to
476 * and return its inode number or 0 if @page is not charged to any cgroup. It
477 * is safe to call this function without holding a reference to @page.
479 * Note, this function is inherently racy, because there is nothing to prevent
480 * the cgroup inode from getting torn down and potentially reallocated a moment
481 * after page_cgroup_ino() returns, so it only should be used by callers that
482 * do not care (such as procfs interfaces).
484 ino_t page_cgroup_ino(struct page *page)
486 struct mem_cgroup *memcg;
487 unsigned long ino = 0;
490 memcg = READ_ONCE(page->mem_cgroup);
491 while (memcg && !(memcg->css.flags & CSS_ONLINE))
492 memcg = parent_mem_cgroup(memcg);
494 ino = cgroup_ino(memcg->css.cgroup);
499 static struct mem_cgroup_per_node *
500 mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
502 int nid = page_to_nid(page);
504 return memcg->nodeinfo[nid];
507 static struct mem_cgroup_tree_per_node *
508 soft_limit_tree_node(int nid)
510 return soft_limit_tree.rb_tree_per_node[nid];
513 static struct mem_cgroup_tree_per_node *
514 soft_limit_tree_from_page(struct page *page)
516 int nid = page_to_nid(page);
518 return soft_limit_tree.rb_tree_per_node[nid];
521 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
522 struct mem_cgroup_tree_per_node *mctz,
523 unsigned long new_usage_in_excess)
525 struct rb_node **p = &mctz->rb_root.rb_node;
526 struct rb_node *parent = NULL;
527 struct mem_cgroup_per_node *mz_node;
528 bool rightmost = true;
533 mz->usage_in_excess = new_usage_in_excess;
534 if (!mz->usage_in_excess)
538 mz_node = rb_entry(parent, struct mem_cgroup_per_node,
540 if (mz->usage_in_excess < mz_node->usage_in_excess) {
546 * We can't avoid mem cgroups that are over their soft
547 * limit by the same amount
549 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
554 mctz->rb_rightmost = &mz->tree_node;
556 rb_link_node(&mz->tree_node, parent, p);
557 rb_insert_color(&mz->tree_node, &mctz->rb_root);
561 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
562 struct mem_cgroup_tree_per_node *mctz)
567 if (&mz->tree_node == mctz->rb_rightmost)
568 mctz->rb_rightmost = rb_prev(&mz->tree_node);
570 rb_erase(&mz->tree_node, &mctz->rb_root);
574 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
575 struct mem_cgroup_tree_per_node *mctz)
579 spin_lock_irqsave(&mctz->lock, flags);
580 __mem_cgroup_remove_exceeded(mz, mctz);
581 spin_unlock_irqrestore(&mctz->lock, flags);
584 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
586 unsigned long nr_pages = page_counter_read(&memcg->memory);
587 unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
588 unsigned long excess = 0;
590 if (nr_pages > soft_limit)
591 excess = nr_pages - soft_limit;
596 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
598 unsigned long excess;
599 struct mem_cgroup_per_node *mz;
600 struct mem_cgroup_tree_per_node *mctz;
602 mctz = soft_limit_tree_from_page(page);
606 * Necessary to update all ancestors when hierarchy is used.
607 * because their event counter is not touched.
609 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
610 mz = mem_cgroup_page_nodeinfo(memcg, page);
611 excess = soft_limit_excess(memcg);
613 * We have to update the tree if mz is on RB-tree or
614 * mem is over its softlimit.
616 if (excess || mz->on_tree) {
619 spin_lock_irqsave(&mctz->lock, flags);
620 /* if on-tree, remove it */
622 __mem_cgroup_remove_exceeded(mz, mctz);
624 * Insert again. mz->usage_in_excess will be updated.
625 * If excess is 0, no tree ops.
627 __mem_cgroup_insert_exceeded(mz, mctz, excess);
628 spin_unlock_irqrestore(&mctz->lock, flags);
633 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
635 struct mem_cgroup_tree_per_node *mctz;
636 struct mem_cgroup_per_node *mz;
640 mz = mem_cgroup_nodeinfo(memcg, nid);
641 mctz = soft_limit_tree_node(nid);
643 mem_cgroup_remove_exceeded(mz, mctz);
647 static struct mem_cgroup_per_node *
648 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
650 struct mem_cgroup_per_node *mz;
654 if (!mctz->rb_rightmost)
655 goto done; /* Nothing to reclaim from */
657 mz = rb_entry(mctz->rb_rightmost,
658 struct mem_cgroup_per_node, tree_node);
660 * Remove the node now but someone else can add it back,
661 * we will to add it back at the end of reclaim to its correct
662 * position in the tree.
664 __mem_cgroup_remove_exceeded(mz, mctz);
665 if (!soft_limit_excess(mz->memcg) ||
666 !css_tryget_online(&mz->memcg->css))
672 static struct mem_cgroup_per_node *
673 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
675 struct mem_cgroup_per_node *mz;
677 spin_lock_irq(&mctz->lock);
678 mz = __mem_cgroup_largest_soft_limit_node(mctz);
679 spin_unlock_irq(&mctz->lock);
683 static unsigned long memcg_sum_events(struct mem_cgroup *memcg,
686 return atomic_long_read(&memcg->events[event]);
689 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
691 bool compound, int nr_pages)
694 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
695 * counted as CACHE even if it's on ANON LRU.
698 __mod_memcg_state(memcg, MEMCG_RSS, nr_pages);
700 __mod_memcg_state(memcg, MEMCG_CACHE, nr_pages);
701 if (PageSwapBacked(page))
702 __mod_memcg_state(memcg, NR_SHMEM, nr_pages);
706 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
707 __mod_memcg_state(memcg, MEMCG_RSS_HUGE, nr_pages);
710 /* pagein of a big page is an event. So, ignore page size */
712 __count_memcg_events(memcg, PGPGIN, 1);
714 __count_memcg_events(memcg, PGPGOUT, 1);
715 nr_pages = -nr_pages; /* for event */
718 __this_cpu_add(memcg->stat_cpu->nr_page_events, nr_pages);
721 unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
722 int nid, unsigned int lru_mask)
724 struct lruvec *lruvec = mem_cgroup_lruvec(NODE_DATA(nid), memcg);
725 unsigned long nr = 0;
728 VM_BUG_ON((unsigned)nid >= nr_node_ids);
731 if (!(BIT(lru) & lru_mask))
733 nr += mem_cgroup_get_lru_size(lruvec, lru);
738 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
739 unsigned int lru_mask)
741 unsigned long nr = 0;
744 for_each_node_state(nid, N_MEMORY)
745 nr += mem_cgroup_node_nr_lru_pages(memcg, nid, lru_mask);
749 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
750 enum mem_cgroup_events_target target)
752 unsigned long val, next;
754 val = __this_cpu_read(memcg->stat_cpu->nr_page_events);
755 next = __this_cpu_read(memcg->stat_cpu->targets[target]);
756 /* from time_after() in jiffies.h */
757 if ((long)(next - val) < 0) {
759 case MEM_CGROUP_TARGET_THRESH:
760 next = val + THRESHOLDS_EVENTS_TARGET;
762 case MEM_CGROUP_TARGET_SOFTLIMIT:
763 next = val + SOFTLIMIT_EVENTS_TARGET;
765 case MEM_CGROUP_TARGET_NUMAINFO:
766 next = val + NUMAINFO_EVENTS_TARGET;
771 __this_cpu_write(memcg->stat_cpu->targets[target], next);
778 * Check events in order.
781 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
783 /* threshold event is triggered in finer grain than soft limit */
784 if (unlikely(mem_cgroup_event_ratelimit(memcg,
785 MEM_CGROUP_TARGET_THRESH))) {
787 bool do_numainfo __maybe_unused;
789 do_softlimit = mem_cgroup_event_ratelimit(memcg,
790 MEM_CGROUP_TARGET_SOFTLIMIT);
792 do_numainfo = mem_cgroup_event_ratelimit(memcg,
793 MEM_CGROUP_TARGET_NUMAINFO);
795 mem_cgroup_threshold(memcg);
796 if (unlikely(do_softlimit))
797 mem_cgroup_update_tree(memcg, page);
799 if (unlikely(do_numainfo))
800 atomic_inc(&memcg->numainfo_events);
805 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
808 * mm_update_next_owner() may clear mm->owner to NULL
809 * if it races with swapoff, page migration, etc.
810 * So this can be called with p == NULL.
815 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
817 EXPORT_SYMBOL(mem_cgroup_from_task);
820 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
821 * @mm: mm from which memcg should be extracted. It can be NULL.
823 * Obtain a reference on mm->memcg and returns it if successful. Otherwise
824 * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is
827 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
829 struct mem_cgroup *memcg;
831 if (mem_cgroup_disabled())
837 * Page cache insertions can happen withou an
838 * actual mm context, e.g. during disk probing
839 * on boot, loopback IO, acct() writes etc.
842 memcg = root_mem_cgroup;
844 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
845 if (unlikely(!memcg))
846 memcg = root_mem_cgroup;
848 } while (!css_tryget_online(&memcg->css));
852 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
855 * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
856 * @page: page from which memcg should be extracted.
858 * Obtain a reference on page->memcg and returns it if successful. Otherwise
859 * root_mem_cgroup is returned.
861 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
863 struct mem_cgroup *memcg = page->mem_cgroup;
865 if (mem_cgroup_disabled())
869 if (!memcg || !css_tryget_online(&memcg->css))
870 memcg = root_mem_cgroup;
874 EXPORT_SYMBOL(get_mem_cgroup_from_page);
877 * If current->active_memcg is non-NULL, do not fallback to current->mm->memcg.
879 static __always_inline struct mem_cgroup *get_mem_cgroup_from_current(void)
881 if (unlikely(current->active_memcg)) {
882 struct mem_cgroup *memcg = root_mem_cgroup;
885 if (css_tryget_online(¤t->active_memcg->css))
886 memcg = current->active_memcg;
890 return get_mem_cgroup_from_mm(current->mm);
894 * mem_cgroup_iter - iterate over memory cgroup hierarchy
895 * @root: hierarchy root
896 * @prev: previously returned memcg, NULL on first invocation
897 * @reclaim: cookie for shared reclaim walks, NULL for full walks
899 * Returns references to children of the hierarchy below @root, or
900 * @root itself, or %NULL after a full round-trip.
902 * Caller must pass the return value in @prev on subsequent
903 * invocations for reference counting, or use mem_cgroup_iter_break()
904 * to cancel a hierarchy walk before the round-trip is complete.
906 * Reclaimers can specify a node and a priority level in @reclaim to
907 * divide up the memcgs in the hierarchy among all concurrent
908 * reclaimers operating on the same node and priority.
910 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
911 struct mem_cgroup *prev,
912 struct mem_cgroup_reclaim_cookie *reclaim)
914 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
915 struct cgroup_subsys_state *css = NULL;
916 struct mem_cgroup *memcg = NULL;
917 struct mem_cgroup *pos = NULL;
919 if (mem_cgroup_disabled())
923 root = root_mem_cgroup;
925 if (prev && !reclaim)
928 if (!root->use_hierarchy && root != root_mem_cgroup) {
937 struct mem_cgroup_per_node *mz;
939 mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
940 iter = &mz->iter[reclaim->priority];
942 if (prev && reclaim->generation != iter->generation)
946 pos = READ_ONCE(iter->position);
947 if (!pos || css_tryget(&pos->css))
950 * css reference reached zero, so iter->position will
951 * be cleared by ->css_released. However, we should not
952 * rely on this happening soon, because ->css_released
953 * is called from a work queue, and by busy-waiting we
954 * might block it. So we clear iter->position right
957 (void)cmpxchg(&iter->position, pos, NULL);
965 css = css_next_descendant_pre(css, &root->css);
968 * Reclaimers share the hierarchy walk, and a
969 * new one might jump in right at the end of
970 * the hierarchy - make sure they see at least
971 * one group and restart from the beginning.
979 * Verify the css and acquire a reference. The root
980 * is provided by the caller, so we know it's alive
981 * and kicking, and don't take an extra reference.
983 memcg = mem_cgroup_from_css(css);
985 if (css == &root->css)
996 * The position could have already been updated by a competing
997 * thread, so check that the value hasn't changed since we read
998 * it to avoid reclaiming from the same cgroup twice.
1000 (void)cmpxchg(&iter->position, pos, memcg);
1008 reclaim->generation = iter->generation;
1014 if (prev && prev != root)
1015 css_put(&prev->css);
1021 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1022 * @root: hierarchy root
1023 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1025 void mem_cgroup_iter_break(struct mem_cgroup *root,
1026 struct mem_cgroup *prev)
1029 root = root_mem_cgroup;
1030 if (prev && prev != root)
1031 css_put(&prev->css);
1034 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
1036 struct mem_cgroup *memcg = dead_memcg;
1037 struct mem_cgroup_reclaim_iter *iter;
1038 struct mem_cgroup_per_node *mz;
1042 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
1043 for_each_node(nid) {
1044 mz = mem_cgroup_nodeinfo(memcg, nid);
1045 for (i = 0; i <= DEF_PRIORITY; i++) {
1046 iter = &mz->iter[i];
1047 cmpxchg(&iter->position,
1055 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1056 * @memcg: hierarchy root
1057 * @fn: function to call for each task
1058 * @arg: argument passed to @fn
1060 * This function iterates over tasks attached to @memcg or to any of its
1061 * descendants and calls @fn for each task. If @fn returns a non-zero
1062 * value, the function breaks the iteration loop and returns the value.
1063 * Otherwise, it will iterate over all tasks and return 0.
1065 * This function must not be called for the root memory cgroup.
1067 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
1068 int (*fn)(struct task_struct *, void *), void *arg)
1070 struct mem_cgroup *iter;
1073 BUG_ON(memcg == root_mem_cgroup);
1075 for_each_mem_cgroup_tree(iter, memcg) {
1076 struct css_task_iter it;
1077 struct task_struct *task;
1079 css_task_iter_start(&iter->css, 0, &it);
1080 while (!ret && (task = css_task_iter_next(&it)))
1081 ret = fn(task, arg);
1082 css_task_iter_end(&it);
1084 mem_cgroup_iter_break(memcg, iter);
1092 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1094 * @pgdat: pgdat of the page
1096 * This function is only safe when following the LRU page isolation
1097 * and putback protocol: the LRU lock must be held, and the page must
1098 * either be PageLRU() or the caller must have isolated/allocated it.
1100 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
1102 struct mem_cgroup_per_node *mz;
1103 struct mem_cgroup *memcg;
1104 struct lruvec *lruvec;
1106 if (mem_cgroup_disabled()) {
1107 lruvec = &pgdat->lruvec;
1111 memcg = page->mem_cgroup;
1113 * Swapcache readahead pages are added to the LRU - and
1114 * possibly migrated - before they are charged.
1117 memcg = root_mem_cgroup;
1119 mz = mem_cgroup_page_nodeinfo(memcg, page);
1120 lruvec = &mz->lruvec;
1123 * Since a node can be onlined after the mem_cgroup was created,
1124 * we have to be prepared to initialize lruvec->zone here;
1125 * and if offlined then reonlined, we need to reinitialize it.
1127 if (unlikely(lruvec->pgdat != pgdat))
1128 lruvec->pgdat = pgdat;
1133 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1134 * @lruvec: mem_cgroup per zone lru vector
1135 * @lru: index of lru list the page is sitting on
1136 * @zid: zone id of the accounted pages
1137 * @nr_pages: positive when adding or negative when removing
1139 * This function must be called under lru_lock, just before a page is added
1140 * to or just after a page is removed from an lru list (that ordering being
1141 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1143 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1144 int zid, int nr_pages)
1146 struct mem_cgroup_per_node *mz;
1147 unsigned long *lru_size;
1150 if (mem_cgroup_disabled())
1153 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1154 lru_size = &mz->lru_zone_size[zid][lru];
1157 *lru_size += nr_pages;
1160 if (WARN_ONCE(size < 0,
1161 "%s(%p, %d, %d): lru_size %ld\n",
1162 __func__, lruvec, lru, nr_pages, size)) {
1168 *lru_size += nr_pages;
1171 bool task_in_mem_cgroup(struct task_struct *task, struct mem_cgroup *memcg)
1173 struct mem_cgroup *task_memcg;
1174 struct task_struct *p;
1177 p = find_lock_task_mm(task);
1179 task_memcg = get_mem_cgroup_from_mm(p->mm);
1183 * All threads may have already detached their mm's, but the oom
1184 * killer still needs to detect if they have already been oom
1185 * killed to prevent needlessly killing additional tasks.
1188 task_memcg = mem_cgroup_from_task(task);
1189 css_get(&task_memcg->css);
1192 ret = mem_cgroup_is_descendant(task_memcg, memcg);
1193 css_put(&task_memcg->css);
1198 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1199 * @memcg: the memory cgroup
1201 * Returns the maximum amount of memory @mem can be charged with, in
1204 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1206 unsigned long margin = 0;
1207 unsigned long count;
1208 unsigned long limit;
1210 count = page_counter_read(&memcg->memory);
1211 limit = READ_ONCE(memcg->memory.max);
1213 margin = limit - count;
1215 if (do_memsw_account()) {
1216 count = page_counter_read(&memcg->memsw);
1217 limit = READ_ONCE(memcg->memsw.max);
1219 margin = min(margin, limit - count);
1228 * A routine for checking "mem" is under move_account() or not.
1230 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1231 * moving cgroups. This is for waiting at high-memory pressure
1234 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1236 struct mem_cgroup *from;
1237 struct mem_cgroup *to;
1240 * Unlike task_move routines, we access mc.to, mc.from not under
1241 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1243 spin_lock(&mc.lock);
1249 ret = mem_cgroup_is_descendant(from, memcg) ||
1250 mem_cgroup_is_descendant(to, memcg);
1252 spin_unlock(&mc.lock);
1256 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1258 if (mc.moving_task && current != mc.moving_task) {
1259 if (mem_cgroup_under_move(memcg)) {
1261 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1262 /* moving charge context might have finished. */
1265 finish_wait(&mc.waitq, &wait);
1272 static const unsigned int memcg1_stats[] = {
1283 static const char *const memcg1_stat_names[] = {
1294 #define K(x) ((x) << (PAGE_SHIFT-10))
1296 * mem_cgroup_print_oom_context: Print OOM information relevant to
1297 * memory controller.
1298 * @memcg: The memory cgroup that went over limit
1299 * @p: Task that is going to be killed
1301 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1304 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
1309 pr_cont(",oom_memcg=");
1310 pr_cont_cgroup_path(memcg->css.cgroup);
1312 pr_cont(",global_oom");
1314 pr_cont(",task_memcg=");
1315 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1321 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1322 * memory controller.
1323 * @memcg: The memory cgroup that went over limit
1325 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1327 struct mem_cgroup *iter;
1330 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1331 K((u64)page_counter_read(&memcg->memory)),
1332 K((u64)memcg->memory.max), memcg->memory.failcnt);
1333 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1334 K((u64)page_counter_read(&memcg->memsw)),
1335 K((u64)memcg->memsw.max), memcg->memsw.failcnt);
1336 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1337 K((u64)page_counter_read(&memcg->kmem)),
1338 K((u64)memcg->kmem.max), memcg->kmem.failcnt);
1340 for_each_mem_cgroup_tree(iter, memcg) {
1341 pr_info("Memory cgroup stats for ");
1342 pr_cont_cgroup_path(iter->css.cgroup);
1345 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
1346 if (memcg1_stats[i] == MEMCG_SWAP && !do_swap_account)
1348 pr_cont(" %s:%luKB", memcg1_stat_names[i],
1349 K(memcg_page_state(iter, memcg1_stats[i])));
1352 for (i = 0; i < NR_LRU_LISTS; i++)
1353 pr_cont(" %s:%luKB", mem_cgroup_lru_names[i],
1354 K(mem_cgroup_nr_lru_pages(iter, BIT(i))));
1361 * Return the memory (and swap, if configured) limit for a memcg.
1363 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
1367 max = memcg->memory.max;
1368 if (mem_cgroup_swappiness(memcg)) {
1369 unsigned long memsw_max;
1370 unsigned long swap_max;
1372 memsw_max = memcg->memsw.max;
1373 swap_max = memcg->swap.max;
1374 swap_max = min(swap_max, (unsigned long)total_swap_pages);
1375 max = min(max + swap_max, memsw_max);
1380 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1383 struct oom_control oc = {
1387 .gfp_mask = gfp_mask,
1392 mutex_lock(&oom_lock);
1393 ret = out_of_memory(&oc);
1394 mutex_unlock(&oom_lock);
1398 #if MAX_NUMNODES > 1
1401 * test_mem_cgroup_node_reclaimable
1402 * @memcg: the target memcg
1403 * @nid: the node ID to be checked.
1404 * @noswap : specify true here if the user wants flle only information.
1406 * This function returns whether the specified memcg contains any
1407 * reclaimable pages on a node. Returns true if there are any reclaimable
1408 * pages in the node.
1410 static bool test_mem_cgroup_node_reclaimable(struct mem_cgroup *memcg,
1411 int nid, bool noswap)
1413 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_FILE))
1415 if (noswap || !total_swap_pages)
1417 if (mem_cgroup_node_nr_lru_pages(memcg, nid, LRU_ALL_ANON))
1424 * Always updating the nodemask is not very good - even if we have an empty
1425 * list or the wrong list here, we can start from some node and traverse all
1426 * nodes based on the zonelist. So update the list loosely once per 10 secs.
1429 static void mem_cgroup_may_update_nodemask(struct mem_cgroup *memcg)
1433 * numainfo_events > 0 means there was at least NUMAINFO_EVENTS_TARGET
1434 * pagein/pageout changes since the last update.
1436 if (!atomic_read(&memcg->numainfo_events))
1438 if (atomic_inc_return(&memcg->numainfo_updating) > 1)
1441 /* make a nodemask where this memcg uses memory from */
1442 memcg->scan_nodes = node_states[N_MEMORY];
1444 for_each_node_mask(nid, node_states[N_MEMORY]) {
1446 if (!test_mem_cgroup_node_reclaimable(memcg, nid, false))
1447 node_clear(nid, memcg->scan_nodes);
1450 atomic_set(&memcg->numainfo_events, 0);
1451 atomic_set(&memcg->numainfo_updating, 0);
1455 * Selecting a node where we start reclaim from. Because what we need is just
1456 * reducing usage counter, start from anywhere is O,K. Considering
1457 * memory reclaim from current node, there are pros. and cons.
1459 * Freeing memory from current node means freeing memory from a node which
1460 * we'll use or we've used. So, it may make LRU bad. And if several threads
1461 * hit limits, it will see a contention on a node. But freeing from remote
1462 * node means more costs for memory reclaim because of memory latency.
1464 * Now, we use round-robin. Better algorithm is welcomed.
1466 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1470 mem_cgroup_may_update_nodemask(memcg);
1471 node = memcg->last_scanned_node;
1473 node = next_node_in(node, memcg->scan_nodes);
1475 * mem_cgroup_may_update_nodemask might have seen no reclaimmable pages
1476 * last time it really checked all the LRUs due to rate limiting.
1477 * Fallback to the current node in that case for simplicity.
1479 if (unlikely(node == MAX_NUMNODES))
1480 node = numa_node_id();
1482 memcg->last_scanned_node = node;
1486 int mem_cgroup_select_victim_node(struct mem_cgroup *memcg)
1492 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1495 unsigned long *total_scanned)
1497 struct mem_cgroup *victim = NULL;
1500 unsigned long excess;
1501 unsigned long nr_scanned;
1502 struct mem_cgroup_reclaim_cookie reclaim = {
1507 excess = soft_limit_excess(root_memcg);
1510 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1515 * If we have not been able to reclaim
1516 * anything, it might because there are
1517 * no reclaimable pages under this hierarchy
1522 * We want to do more targeted reclaim.
1523 * excess >> 2 is not to excessive so as to
1524 * reclaim too much, nor too less that we keep
1525 * coming back to reclaim from this cgroup
1527 if (total >= (excess >> 2) ||
1528 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1533 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1534 pgdat, &nr_scanned);
1535 *total_scanned += nr_scanned;
1536 if (!soft_limit_excess(root_memcg))
1539 mem_cgroup_iter_break(root_memcg, victim);
1543 #ifdef CONFIG_LOCKDEP
1544 static struct lockdep_map memcg_oom_lock_dep_map = {
1545 .name = "memcg_oom_lock",
1549 static DEFINE_SPINLOCK(memcg_oom_lock);
1552 * Check OOM-Killer is already running under our hierarchy.
1553 * If someone is running, return false.
1555 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1557 struct mem_cgroup *iter, *failed = NULL;
1559 spin_lock(&memcg_oom_lock);
1561 for_each_mem_cgroup_tree(iter, memcg) {
1562 if (iter->oom_lock) {
1564 * this subtree of our hierarchy is already locked
1565 * so we cannot give a lock.
1568 mem_cgroup_iter_break(memcg, iter);
1571 iter->oom_lock = true;
1576 * OK, we failed to lock the whole subtree so we have
1577 * to clean up what we set up to the failing subtree
1579 for_each_mem_cgroup_tree(iter, memcg) {
1580 if (iter == failed) {
1581 mem_cgroup_iter_break(memcg, iter);
1584 iter->oom_lock = false;
1587 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1589 spin_unlock(&memcg_oom_lock);
1594 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1596 struct mem_cgroup *iter;
1598 spin_lock(&memcg_oom_lock);
1599 mutex_release(&memcg_oom_lock_dep_map, 1, _RET_IP_);
1600 for_each_mem_cgroup_tree(iter, memcg)
1601 iter->oom_lock = false;
1602 spin_unlock(&memcg_oom_lock);
1605 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1607 struct mem_cgroup *iter;
1609 spin_lock(&memcg_oom_lock);
1610 for_each_mem_cgroup_tree(iter, memcg)
1612 spin_unlock(&memcg_oom_lock);
1615 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1617 struct mem_cgroup *iter;
1620 * When a new child is created while the hierarchy is under oom,
1621 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1623 spin_lock(&memcg_oom_lock);
1624 for_each_mem_cgroup_tree(iter, memcg)
1625 if (iter->under_oom > 0)
1627 spin_unlock(&memcg_oom_lock);
1630 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1632 struct oom_wait_info {
1633 struct mem_cgroup *memcg;
1634 wait_queue_entry_t wait;
1637 static int memcg_oom_wake_function(wait_queue_entry_t *wait,
1638 unsigned mode, int sync, void *arg)
1640 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1641 struct mem_cgroup *oom_wait_memcg;
1642 struct oom_wait_info *oom_wait_info;
1644 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1645 oom_wait_memcg = oom_wait_info->memcg;
1647 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1648 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1650 return autoremove_wake_function(wait, mode, sync, arg);
1653 static void memcg_oom_recover(struct mem_cgroup *memcg)
1656 * For the following lockless ->under_oom test, the only required
1657 * guarantee is that it must see the state asserted by an OOM when
1658 * this function is called as a result of userland actions
1659 * triggered by the notification of the OOM. This is trivially
1660 * achieved by invoking mem_cgroup_mark_under_oom() before
1661 * triggering notification.
1663 if (memcg && memcg->under_oom)
1664 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1674 static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1676 enum oom_status ret;
1679 if (order > PAGE_ALLOC_COSTLY_ORDER)
1682 memcg_memory_event(memcg, MEMCG_OOM);
1685 * We are in the middle of the charge context here, so we
1686 * don't want to block when potentially sitting on a callstack
1687 * that holds all kinds of filesystem and mm locks.
1689 * cgroup1 allows disabling the OOM killer and waiting for outside
1690 * handling until the charge can succeed; remember the context and put
1691 * the task to sleep at the end of the page fault when all locks are
1694 * On the other hand, in-kernel OOM killer allows for an async victim
1695 * memory reclaim (oom_reaper) and that means that we are not solely
1696 * relying on the oom victim to make a forward progress and we can
1697 * invoke the oom killer here.
1699 * Please note that mem_cgroup_out_of_memory might fail to find a
1700 * victim and then we have to bail out from the charge path.
1702 if (memcg->oom_kill_disable) {
1703 if (!current->in_user_fault)
1705 css_get(&memcg->css);
1706 current->memcg_in_oom = memcg;
1707 current->memcg_oom_gfp_mask = mask;
1708 current->memcg_oom_order = order;
1713 mem_cgroup_mark_under_oom(memcg);
1715 locked = mem_cgroup_oom_trylock(memcg);
1718 mem_cgroup_oom_notify(memcg);
1720 mem_cgroup_unmark_under_oom(memcg);
1721 if (mem_cgroup_out_of_memory(memcg, mask, order))
1727 mem_cgroup_oom_unlock(memcg);
1733 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1734 * @handle: actually kill/wait or just clean up the OOM state
1736 * This has to be called at the end of a page fault if the memcg OOM
1737 * handler was enabled.
1739 * Memcg supports userspace OOM handling where failed allocations must
1740 * sleep on a waitqueue until the userspace task resolves the
1741 * situation. Sleeping directly in the charge context with all kinds
1742 * of locks held is not a good idea, instead we remember an OOM state
1743 * in the task and mem_cgroup_oom_synchronize() has to be called at
1744 * the end of the page fault to complete the OOM handling.
1746 * Returns %true if an ongoing memcg OOM situation was detected and
1747 * completed, %false otherwise.
1749 bool mem_cgroup_oom_synchronize(bool handle)
1751 struct mem_cgroup *memcg = current->memcg_in_oom;
1752 struct oom_wait_info owait;
1755 /* OOM is global, do not handle */
1762 owait.memcg = memcg;
1763 owait.wait.flags = 0;
1764 owait.wait.func = memcg_oom_wake_function;
1765 owait.wait.private = current;
1766 INIT_LIST_HEAD(&owait.wait.entry);
1768 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1769 mem_cgroup_mark_under_oom(memcg);
1771 locked = mem_cgroup_oom_trylock(memcg);
1774 mem_cgroup_oom_notify(memcg);
1776 if (locked && !memcg->oom_kill_disable) {
1777 mem_cgroup_unmark_under_oom(memcg);
1778 finish_wait(&memcg_oom_waitq, &owait.wait);
1779 mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
1780 current->memcg_oom_order);
1783 mem_cgroup_unmark_under_oom(memcg);
1784 finish_wait(&memcg_oom_waitq, &owait.wait);
1788 mem_cgroup_oom_unlock(memcg);
1790 * There is no guarantee that an OOM-lock contender
1791 * sees the wakeups triggered by the OOM kill
1792 * uncharges. Wake any sleepers explicitely.
1794 memcg_oom_recover(memcg);
1797 current->memcg_in_oom = NULL;
1798 css_put(&memcg->css);
1803 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1804 * @victim: task to be killed by the OOM killer
1805 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1807 * Returns a pointer to a memory cgroup, which has to be cleaned up
1808 * by killing all belonging OOM-killable tasks.
1810 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1812 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
1813 struct mem_cgroup *oom_domain)
1815 struct mem_cgroup *oom_group = NULL;
1816 struct mem_cgroup *memcg;
1818 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
1822 oom_domain = root_mem_cgroup;
1826 memcg = mem_cgroup_from_task(victim);
1827 if (memcg == root_mem_cgroup)
1831 * Traverse the memory cgroup hierarchy from the victim task's
1832 * cgroup up to the OOMing cgroup (or root) to find the
1833 * highest-level memory cgroup with oom.group set.
1835 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
1836 if (memcg->oom_group)
1839 if (memcg == oom_domain)
1844 css_get(&oom_group->css);
1851 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
1853 pr_info("Tasks in ");
1854 pr_cont_cgroup_path(memcg->css.cgroup);
1855 pr_cont(" are going to be killed due to memory.oom.group set\n");
1859 * lock_page_memcg - lock a page->mem_cgroup binding
1862 * This function protects unlocked LRU pages from being moved to
1865 * It ensures lifetime of the returned memcg. Caller is responsible
1866 * for the lifetime of the page; __unlock_page_memcg() is available
1867 * when @page might get freed inside the locked section.
1869 struct mem_cgroup *lock_page_memcg(struct page *page)
1871 struct mem_cgroup *memcg;
1872 unsigned long flags;
1875 * The RCU lock is held throughout the transaction. The fast
1876 * path can get away without acquiring the memcg->move_lock
1877 * because page moving starts with an RCU grace period.
1879 * The RCU lock also protects the memcg from being freed when
1880 * the page state that is going to change is the only thing
1881 * preventing the page itself from being freed. E.g. writeback
1882 * doesn't hold a page reference and relies on PG_writeback to
1883 * keep off truncation, migration and so forth.
1887 if (mem_cgroup_disabled())
1890 memcg = page->mem_cgroup;
1891 if (unlikely(!memcg))
1894 if (atomic_read(&memcg->moving_account) <= 0)
1897 spin_lock_irqsave(&memcg->move_lock, flags);
1898 if (memcg != page->mem_cgroup) {
1899 spin_unlock_irqrestore(&memcg->move_lock, flags);
1904 * When charge migration first begins, we can have locked and
1905 * unlocked page stat updates happening concurrently. Track
1906 * the task who has the lock for unlock_page_memcg().
1908 memcg->move_lock_task = current;
1909 memcg->move_lock_flags = flags;
1913 EXPORT_SYMBOL(lock_page_memcg);
1916 * __unlock_page_memcg - unlock and unpin a memcg
1919 * Unlock and unpin a memcg returned by lock_page_memcg().
1921 void __unlock_page_memcg(struct mem_cgroup *memcg)
1923 if (memcg && memcg->move_lock_task == current) {
1924 unsigned long flags = memcg->move_lock_flags;
1926 memcg->move_lock_task = NULL;
1927 memcg->move_lock_flags = 0;
1929 spin_unlock_irqrestore(&memcg->move_lock, flags);
1936 * unlock_page_memcg - unlock a page->mem_cgroup binding
1939 void unlock_page_memcg(struct page *page)
1941 __unlock_page_memcg(page->mem_cgroup);
1943 EXPORT_SYMBOL(unlock_page_memcg);
1945 struct memcg_stock_pcp {
1946 struct mem_cgroup *cached; /* this never be root cgroup */
1947 unsigned int nr_pages;
1948 struct work_struct work;
1949 unsigned long flags;
1950 #define FLUSHING_CACHED_CHARGE 0
1952 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
1953 static DEFINE_MUTEX(percpu_charge_mutex);
1956 * consume_stock: Try to consume stocked charge on this cpu.
1957 * @memcg: memcg to consume from.
1958 * @nr_pages: how many pages to charge.
1960 * The charges will only happen if @memcg matches the current cpu's memcg
1961 * stock, and at least @nr_pages are available in that stock. Failure to
1962 * service an allocation will refill the stock.
1964 * returns true if successful, false otherwise.
1966 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
1968 struct memcg_stock_pcp *stock;
1969 unsigned long flags;
1972 if (nr_pages > MEMCG_CHARGE_BATCH)
1975 local_irq_save(flags);
1977 stock = this_cpu_ptr(&memcg_stock);
1978 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
1979 stock->nr_pages -= nr_pages;
1983 local_irq_restore(flags);
1989 * Returns stocks cached in percpu and reset cached information.
1991 static void drain_stock(struct memcg_stock_pcp *stock)
1993 struct mem_cgroup *old = stock->cached;
1995 if (stock->nr_pages) {
1996 page_counter_uncharge(&old->memory, stock->nr_pages);
1997 if (do_memsw_account())
1998 page_counter_uncharge(&old->memsw, stock->nr_pages);
1999 css_put_many(&old->css, stock->nr_pages);
2000 stock->nr_pages = 0;
2002 stock->cached = NULL;
2005 static void drain_local_stock(struct work_struct *dummy)
2007 struct memcg_stock_pcp *stock;
2008 unsigned long flags;
2011 * The only protection from memory hotplug vs. drain_stock races is
2012 * that we always operate on local CPU stock here with IRQ disabled
2014 local_irq_save(flags);
2016 stock = this_cpu_ptr(&memcg_stock);
2018 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2020 local_irq_restore(flags);
2024 * Cache charges(val) to local per_cpu area.
2025 * This will be consumed by consume_stock() function, later.
2027 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2029 struct memcg_stock_pcp *stock;
2030 unsigned long flags;
2032 local_irq_save(flags);
2034 stock = this_cpu_ptr(&memcg_stock);
2035 if (stock->cached != memcg) { /* reset if necessary */
2037 stock->cached = memcg;
2039 stock->nr_pages += nr_pages;
2041 if (stock->nr_pages > MEMCG_CHARGE_BATCH)
2044 local_irq_restore(flags);
2048 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2049 * of the hierarchy under it.
2051 static void drain_all_stock(struct mem_cgroup *root_memcg)
2055 /* If someone's already draining, avoid adding running more workers. */
2056 if (!mutex_trylock(&percpu_charge_mutex))
2059 * Notify other cpus that system-wide "drain" is running
2060 * We do not care about races with the cpu hotplug because cpu down
2061 * as well as workers from this path always operate on the local
2062 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2065 for_each_online_cpu(cpu) {
2066 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2067 struct mem_cgroup *memcg;
2069 memcg = stock->cached;
2070 if (!memcg || !stock->nr_pages || !css_tryget(&memcg->css))
2072 if (!mem_cgroup_is_descendant(memcg, root_memcg)) {
2073 css_put(&memcg->css);
2076 if (!test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2078 drain_local_stock(&stock->work);
2080 schedule_work_on(cpu, &stock->work);
2082 css_put(&memcg->css);
2085 mutex_unlock(&percpu_charge_mutex);
2088 static int memcg_hotplug_cpu_dead(unsigned int cpu)
2090 struct memcg_stock_pcp *stock;
2091 struct mem_cgroup *memcg;
2093 stock = &per_cpu(memcg_stock, cpu);
2096 for_each_mem_cgroup(memcg) {
2099 for (i = 0; i < MEMCG_NR_STAT; i++) {
2103 x = this_cpu_xchg(memcg->stat_cpu->count[i], 0);
2105 atomic_long_add(x, &memcg->stat[i]);
2107 if (i >= NR_VM_NODE_STAT_ITEMS)
2110 for_each_node(nid) {
2111 struct mem_cgroup_per_node *pn;
2113 pn = mem_cgroup_nodeinfo(memcg, nid);
2114 x = this_cpu_xchg(pn->lruvec_stat_cpu->count[i], 0);
2116 atomic_long_add(x, &pn->lruvec_stat[i]);
2120 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
2123 x = this_cpu_xchg(memcg->stat_cpu->events[i], 0);
2125 atomic_long_add(x, &memcg->events[i]);
2132 static void reclaim_high(struct mem_cgroup *memcg,
2133 unsigned int nr_pages,
2137 if (page_counter_read(&memcg->memory) <= memcg->high)
2139 memcg_memory_event(memcg, MEMCG_HIGH);
2140 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
2141 } while ((memcg = parent_mem_cgroup(memcg)));
2144 static void high_work_func(struct work_struct *work)
2146 struct mem_cgroup *memcg;
2148 memcg = container_of(work, struct mem_cgroup, high_work);
2149 reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
2153 * Scheduled by try_charge() to be executed from the userland return path
2154 * and reclaims memory over the high limit.
2156 void mem_cgroup_handle_over_high(void)
2158 unsigned int nr_pages = current->memcg_nr_pages_over_high;
2159 struct mem_cgroup *memcg;
2161 if (likely(!nr_pages))
2164 memcg = get_mem_cgroup_from_mm(current->mm);
2165 reclaim_high(memcg, nr_pages, GFP_KERNEL);
2166 css_put(&memcg->css);
2167 current->memcg_nr_pages_over_high = 0;
2170 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2171 unsigned int nr_pages)
2173 unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
2174 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2175 struct mem_cgroup *mem_over_limit;
2176 struct page_counter *counter;
2177 unsigned long nr_reclaimed;
2178 bool may_swap = true;
2179 bool drained = false;
2181 enum oom_status oom_status;
2183 if (mem_cgroup_is_root(memcg))
2186 if (consume_stock(memcg, nr_pages))
2189 if (!do_memsw_account() ||
2190 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2191 if (page_counter_try_charge(&memcg->memory, batch, &counter))
2193 if (do_memsw_account())
2194 page_counter_uncharge(&memcg->memsw, batch);
2195 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2197 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2201 if (batch > nr_pages) {
2207 * Unlike in global OOM situations, memcg is not in a physical
2208 * memory shortage. Allow dying and OOM-killed tasks to
2209 * bypass the last charges so that they can exit quickly and
2210 * free their memory.
2212 if (unlikely(tsk_is_oom_victim(current) ||
2213 fatal_signal_pending(current) ||
2214 current->flags & PF_EXITING))
2218 * Prevent unbounded recursion when reclaim operations need to
2219 * allocate memory. This might exceed the limits temporarily,
2220 * but we prefer facilitating memory reclaim and getting back
2221 * under the limit over triggering OOM kills in these cases.
2223 if (unlikely(current->flags & PF_MEMALLOC))
2226 if (unlikely(task_in_memcg_oom(current)))
2229 if (!gfpflags_allow_blocking(gfp_mask))
2232 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2234 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2235 gfp_mask, may_swap);
2237 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2241 drain_all_stock(mem_over_limit);
2246 if (gfp_mask & __GFP_NORETRY)
2249 * Even though the limit is exceeded at this point, reclaim
2250 * may have been able to free some pages. Retry the charge
2251 * before killing the task.
2253 * Only for regular pages, though: huge pages are rather
2254 * unlikely to succeed so close to the limit, and we fall back
2255 * to regular pages anyway in case of failure.
2257 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2260 * At task move, charge accounts can be doubly counted. So, it's
2261 * better to wait until the end of task_move if something is going on.
2263 if (mem_cgroup_wait_acct_move(mem_over_limit))
2269 if (gfp_mask & __GFP_RETRY_MAYFAIL && oomed)
2272 if (gfp_mask & __GFP_NOFAIL)
2275 if (fatal_signal_pending(current))
2279 * keep retrying as long as the memcg oom killer is able to make
2280 * a forward progress or bypass the charge if the oom killer
2281 * couldn't make any progress.
2283 oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask,
2284 get_order(nr_pages * PAGE_SIZE));
2285 switch (oom_status) {
2287 nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2296 if (!(gfp_mask & __GFP_NOFAIL))
2300 * The allocation either can't fail or will lead to more memory
2301 * being freed very soon. Allow memory usage go over the limit
2302 * temporarily by force charging it.
2304 page_counter_charge(&memcg->memory, nr_pages);
2305 if (do_memsw_account())
2306 page_counter_charge(&memcg->memsw, nr_pages);
2307 css_get_many(&memcg->css, nr_pages);
2312 css_get_many(&memcg->css, batch);
2313 if (batch > nr_pages)
2314 refill_stock(memcg, batch - nr_pages);
2317 * If the hierarchy is above the normal consumption range, schedule
2318 * reclaim on returning to userland. We can perform reclaim here
2319 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2320 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2321 * not recorded as it most likely matches current's and won't
2322 * change in the meantime. As high limit is checked again before
2323 * reclaim, the cost of mismatch is negligible.
2326 if (page_counter_read(&memcg->memory) > memcg->high) {
2327 /* Don't bother a random interrupted task */
2328 if (in_interrupt()) {
2329 schedule_work(&memcg->high_work);
2332 current->memcg_nr_pages_over_high += batch;
2333 set_notify_resume(current);
2336 } while ((memcg = parent_mem_cgroup(memcg)));
2341 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2343 if (mem_cgroup_is_root(memcg))
2346 page_counter_uncharge(&memcg->memory, nr_pages);
2347 if (do_memsw_account())
2348 page_counter_uncharge(&memcg->memsw, nr_pages);
2350 css_put_many(&memcg->css, nr_pages);
2353 static void lock_page_lru(struct page *page, int *isolated)
2355 struct zone *zone = page_zone(page);
2357 spin_lock_irq(zone_lru_lock(zone));
2358 if (PageLRU(page)) {
2359 struct lruvec *lruvec;
2361 lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
2363 del_page_from_lru_list(page, lruvec, page_lru(page));
2369 static void unlock_page_lru(struct page *page, int isolated)
2371 struct zone *zone = page_zone(page);
2374 struct lruvec *lruvec;
2376 lruvec = mem_cgroup_page_lruvec(page, zone->zone_pgdat);
2377 VM_BUG_ON_PAGE(PageLRU(page), page);
2379 add_page_to_lru_list(page, lruvec, page_lru(page));
2381 spin_unlock_irq(zone_lru_lock(zone));
2384 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2389 VM_BUG_ON_PAGE(page->mem_cgroup, page);
2392 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2393 * may already be on some other mem_cgroup's LRU. Take care of it.
2396 lock_page_lru(page, &isolated);
2399 * Nobody should be changing or seriously looking at
2400 * page->mem_cgroup at this point:
2402 * - the page is uncharged
2404 * - the page is off-LRU
2406 * - an anonymous fault has exclusive page access, except for
2407 * a locked page table
2409 * - a page cache insertion, a swapin fault, or a migration
2410 * have the page locked
2412 page->mem_cgroup = memcg;
2415 unlock_page_lru(page, isolated);
2418 #ifdef CONFIG_MEMCG_KMEM
2419 static int memcg_alloc_cache_id(void)
2424 id = ida_simple_get(&memcg_cache_ida,
2425 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2429 if (id < memcg_nr_cache_ids)
2433 * There's no space for the new id in memcg_caches arrays,
2434 * so we have to grow them.
2436 down_write(&memcg_cache_ids_sem);
2438 size = 2 * (id + 1);
2439 if (size < MEMCG_CACHES_MIN_SIZE)
2440 size = MEMCG_CACHES_MIN_SIZE;
2441 else if (size > MEMCG_CACHES_MAX_SIZE)
2442 size = MEMCG_CACHES_MAX_SIZE;
2444 err = memcg_update_all_caches(size);
2446 err = memcg_update_all_list_lrus(size);
2448 memcg_nr_cache_ids = size;
2450 up_write(&memcg_cache_ids_sem);
2453 ida_simple_remove(&memcg_cache_ida, id);
2459 static void memcg_free_cache_id(int id)
2461 ida_simple_remove(&memcg_cache_ida, id);
2464 struct memcg_kmem_cache_create_work {
2465 struct mem_cgroup *memcg;
2466 struct kmem_cache *cachep;
2467 struct work_struct work;
2470 static void memcg_kmem_cache_create_func(struct work_struct *w)
2472 struct memcg_kmem_cache_create_work *cw =
2473 container_of(w, struct memcg_kmem_cache_create_work, work);
2474 struct mem_cgroup *memcg = cw->memcg;
2475 struct kmem_cache *cachep = cw->cachep;
2477 memcg_create_kmem_cache(memcg, cachep);
2479 css_put(&memcg->css);
2484 * Enqueue the creation of a per-memcg kmem_cache.
2486 static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
2487 struct kmem_cache *cachep)
2489 struct memcg_kmem_cache_create_work *cw;
2491 cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
2495 css_get(&memcg->css);
2498 cw->cachep = cachep;
2499 INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
2501 queue_work(memcg_kmem_cache_wq, &cw->work);
2504 static inline bool memcg_kmem_bypass(void)
2506 if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
2512 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2513 * @cachep: the original global kmem cache
2515 * Return the kmem_cache we're supposed to use for a slab allocation.
2516 * We try to use the current memcg's version of the cache.
2518 * If the cache does not exist yet, if we are the first user of it, we
2519 * create it asynchronously in a workqueue and let the current allocation
2520 * go through with the original cache.
2522 * This function takes a reference to the cache it returns to assure it
2523 * won't get destroyed while we are working with it. Once the caller is
2524 * done with it, memcg_kmem_put_cache() must be called to release the
2527 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
2529 struct mem_cgroup *memcg;
2530 struct kmem_cache *memcg_cachep;
2533 VM_BUG_ON(!is_root_cache(cachep));
2535 if (memcg_kmem_bypass())
2538 memcg = get_mem_cgroup_from_current();
2539 kmemcg_id = READ_ONCE(memcg->kmemcg_id);
2543 memcg_cachep = cache_from_memcg_idx(cachep, kmemcg_id);
2544 if (likely(memcg_cachep))
2545 return memcg_cachep;
2548 * If we are in a safe context (can wait, and not in interrupt
2549 * context), we could be be predictable and return right away.
2550 * This would guarantee that the allocation being performed
2551 * already belongs in the new cache.
2553 * However, there are some clashes that can arrive from locking.
2554 * For instance, because we acquire the slab_mutex while doing
2555 * memcg_create_kmem_cache, this means no further allocation
2556 * could happen with the slab_mutex held. So it's better to
2559 memcg_schedule_kmem_cache_create(memcg, cachep);
2561 css_put(&memcg->css);
2566 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2567 * @cachep: the cache returned by memcg_kmem_get_cache
2569 void memcg_kmem_put_cache(struct kmem_cache *cachep)
2571 if (!is_root_cache(cachep))
2572 css_put(&cachep->memcg_params.memcg->css);
2576 * memcg_kmem_charge_memcg: charge a kmem page
2577 * @page: page to charge
2578 * @gfp: reclaim mode
2579 * @order: allocation order
2580 * @memcg: memory cgroup to charge
2582 * Returns 0 on success, an error code on failure.
2584 int memcg_kmem_charge_memcg(struct page *page, gfp_t gfp, int order,
2585 struct mem_cgroup *memcg)
2587 unsigned int nr_pages = 1 << order;
2588 struct page_counter *counter;
2591 ret = try_charge(memcg, gfp, nr_pages);
2595 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
2596 !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
2597 cancel_charge(memcg, nr_pages);
2601 page->mem_cgroup = memcg;
2607 * memcg_kmem_charge: charge a kmem page to the current memory cgroup
2608 * @page: page to charge
2609 * @gfp: reclaim mode
2610 * @order: allocation order
2612 * Returns 0 on success, an error code on failure.
2614 int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
2616 struct mem_cgroup *memcg;
2619 if (mem_cgroup_disabled() || memcg_kmem_bypass())
2622 memcg = get_mem_cgroup_from_current();
2623 if (!mem_cgroup_is_root(memcg)) {
2624 ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
2626 __SetPageKmemcg(page);
2628 css_put(&memcg->css);
2632 * memcg_kmem_uncharge: uncharge a kmem page
2633 * @page: page to uncharge
2634 * @order: allocation order
2636 void memcg_kmem_uncharge(struct page *page, int order)
2638 struct mem_cgroup *memcg = page->mem_cgroup;
2639 unsigned int nr_pages = 1 << order;
2644 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
2646 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2647 page_counter_uncharge(&memcg->kmem, nr_pages);
2649 page_counter_uncharge(&memcg->memory, nr_pages);
2650 if (do_memsw_account())
2651 page_counter_uncharge(&memcg->memsw, nr_pages);
2653 page->mem_cgroup = NULL;
2655 /* slab pages do not have PageKmemcg flag set */
2656 if (PageKmemcg(page))
2657 __ClearPageKmemcg(page);
2659 css_put_many(&memcg->css, nr_pages);
2661 #endif /* CONFIG_MEMCG_KMEM */
2663 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2666 * Because tail pages are not marked as "used", set it. We're under
2667 * zone_lru_lock and migration entries setup in all page mappings.
2669 void mem_cgroup_split_huge_fixup(struct page *head)
2673 if (mem_cgroup_disabled())
2676 for (i = 1; i < HPAGE_PMD_NR; i++)
2677 head[i].mem_cgroup = head->mem_cgroup;
2679 __mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PMD_NR);
2681 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
2683 #ifdef CONFIG_MEMCG_SWAP
2685 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
2686 * @entry: swap entry to be moved
2687 * @from: mem_cgroup which the entry is moved from
2688 * @to: mem_cgroup which the entry is moved to
2690 * It succeeds only when the swap_cgroup's record for this entry is the same
2691 * as the mem_cgroup's id of @from.
2693 * Returns 0 on success, -EINVAL on failure.
2695 * The caller must have charged to @to, IOW, called page_counter_charge() about
2696 * both res and memsw, and called css_get().
2698 static int mem_cgroup_move_swap_account(swp_entry_t entry,
2699 struct mem_cgroup *from, struct mem_cgroup *to)
2701 unsigned short old_id, new_id;
2703 old_id = mem_cgroup_id(from);
2704 new_id = mem_cgroup_id(to);
2706 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
2707 mod_memcg_state(from, MEMCG_SWAP, -1);
2708 mod_memcg_state(to, MEMCG_SWAP, 1);
2714 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
2715 struct mem_cgroup *from, struct mem_cgroup *to)
2721 static DEFINE_MUTEX(memcg_max_mutex);
2723 static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
2724 unsigned long max, bool memsw)
2726 bool enlarge = false;
2727 bool drained = false;
2729 bool limits_invariant;
2730 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
2733 if (signal_pending(current)) {
2738 mutex_lock(&memcg_max_mutex);
2740 * Make sure that the new limit (memsw or memory limit) doesn't
2741 * break our basic invariant rule memory.max <= memsw.max.
2743 limits_invariant = memsw ? max >= memcg->memory.max :
2744 max <= memcg->memsw.max;
2745 if (!limits_invariant) {
2746 mutex_unlock(&memcg_max_mutex);
2750 if (max > counter->max)
2752 ret = page_counter_set_max(counter, max);
2753 mutex_unlock(&memcg_max_mutex);
2759 drain_all_stock(memcg);
2764 if (!try_to_free_mem_cgroup_pages(memcg, 1,
2765 GFP_KERNEL, !memsw)) {
2771 if (!ret && enlarge)
2772 memcg_oom_recover(memcg);
2777 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
2779 unsigned long *total_scanned)
2781 unsigned long nr_reclaimed = 0;
2782 struct mem_cgroup_per_node *mz, *next_mz = NULL;
2783 unsigned long reclaimed;
2785 struct mem_cgroup_tree_per_node *mctz;
2786 unsigned long excess;
2787 unsigned long nr_scanned;
2792 mctz = soft_limit_tree_node(pgdat->node_id);
2795 * Do not even bother to check the largest node if the root
2796 * is empty. Do it lockless to prevent lock bouncing. Races
2797 * are acceptable as soft limit is best effort anyway.
2799 if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
2803 * This loop can run a while, specially if mem_cgroup's continuously
2804 * keep exceeding their soft limit and putting the system under
2811 mz = mem_cgroup_largest_soft_limit_node(mctz);
2816 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
2817 gfp_mask, &nr_scanned);
2818 nr_reclaimed += reclaimed;
2819 *total_scanned += nr_scanned;
2820 spin_lock_irq(&mctz->lock);
2821 __mem_cgroup_remove_exceeded(mz, mctz);
2824 * If we failed to reclaim anything from this memory cgroup
2825 * it is time to move on to the next cgroup
2829 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
2831 excess = soft_limit_excess(mz->memcg);
2833 * One school of thought says that we should not add
2834 * back the node to the tree if reclaim returns 0.
2835 * But our reclaim could return 0, simply because due
2836 * to priority we are exposing a smaller subset of
2837 * memory to reclaim from. Consider this as a longer
2840 /* If excess == 0, no tree ops */
2841 __mem_cgroup_insert_exceeded(mz, mctz, excess);
2842 spin_unlock_irq(&mctz->lock);
2843 css_put(&mz->memcg->css);
2846 * Could not reclaim anything and there are no more
2847 * mem cgroups to try or we seem to be looping without
2848 * reclaiming anything.
2850 if (!nr_reclaimed &&
2852 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
2854 } while (!nr_reclaimed);
2856 css_put(&next_mz->memcg->css);
2857 return nr_reclaimed;
2861 * Test whether @memcg has children, dead or alive. Note that this
2862 * function doesn't care whether @memcg has use_hierarchy enabled and
2863 * returns %true if there are child csses according to the cgroup
2864 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
2866 static inline bool memcg_has_children(struct mem_cgroup *memcg)
2871 ret = css_next_child(NULL, &memcg->css);
2877 * Reclaims as many pages from the given memcg as possible.
2879 * Caller is responsible for holding css reference for memcg.
2881 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
2883 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2885 /* we call try-to-free pages for make this cgroup empty */
2886 lru_add_drain_all();
2888 drain_all_stock(memcg);
2890 /* try to free all pages in this cgroup */
2891 while (nr_retries && page_counter_read(&memcg->memory)) {
2894 if (signal_pending(current))
2897 progress = try_to_free_mem_cgroup_pages(memcg, 1,
2901 /* maybe some writeback is necessary */
2902 congestion_wait(BLK_RW_ASYNC, HZ/10);
2910 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
2911 char *buf, size_t nbytes,
2914 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
2916 if (mem_cgroup_is_root(memcg))
2918 return mem_cgroup_force_empty(memcg) ?: nbytes;
2921 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
2924 return mem_cgroup_from_css(css)->use_hierarchy;
2927 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
2928 struct cftype *cft, u64 val)
2931 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
2932 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
2934 if (memcg->use_hierarchy == val)
2938 * If parent's use_hierarchy is set, we can't make any modifications
2939 * in the child subtrees. If it is unset, then the change can
2940 * occur, provided the current cgroup has no children.
2942 * For the root cgroup, parent_mem is NULL, we allow value to be
2943 * set if there are no children.
2945 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
2946 (val == 1 || val == 0)) {
2947 if (!memcg_has_children(memcg))
2948 memcg->use_hierarchy = val;
2957 struct accumulated_stats {
2958 unsigned long stat[MEMCG_NR_STAT];
2959 unsigned long events[NR_VM_EVENT_ITEMS];
2960 unsigned long lru_pages[NR_LRU_LISTS];
2961 const unsigned int *stats_array;
2962 const unsigned int *events_array;
2967 static void accumulate_memcg_tree(struct mem_cgroup *memcg,
2968 struct accumulated_stats *acc)
2970 struct mem_cgroup *mi;
2973 for_each_mem_cgroup_tree(mi, memcg) {
2974 for (i = 0; i < acc->stats_size; i++)
2975 acc->stat[i] += memcg_page_state(mi,
2976 acc->stats_array ? acc->stats_array[i] : i);
2978 for (i = 0; i < acc->events_size; i++)
2979 acc->events[i] += memcg_sum_events(mi,
2980 acc->events_array ? acc->events_array[i] : i);
2982 for (i = 0; i < NR_LRU_LISTS; i++)
2983 acc->lru_pages[i] +=
2984 mem_cgroup_nr_lru_pages(mi, BIT(i));
2988 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
2990 unsigned long val = 0;
2992 if (mem_cgroup_is_root(memcg)) {
2993 struct mem_cgroup *iter;
2995 for_each_mem_cgroup_tree(iter, memcg) {
2996 val += memcg_page_state(iter, MEMCG_CACHE);
2997 val += memcg_page_state(iter, MEMCG_RSS);
2999 val += memcg_page_state(iter, MEMCG_SWAP);
3003 val = page_counter_read(&memcg->memory);
3005 val = page_counter_read(&memcg->memsw);
3018 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3021 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3022 struct page_counter *counter;
3024 switch (MEMFILE_TYPE(cft->private)) {
3026 counter = &memcg->memory;
3029 counter = &memcg->memsw;
3032 counter = &memcg->kmem;
3035 counter = &memcg->tcpmem;
3041 switch (MEMFILE_ATTR(cft->private)) {
3043 if (counter == &memcg->memory)
3044 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
3045 if (counter == &memcg->memsw)
3046 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
3047 return (u64)page_counter_read(counter) * PAGE_SIZE;
3049 return (u64)counter->max * PAGE_SIZE;
3051 return (u64)counter->watermark * PAGE_SIZE;
3053 return counter->failcnt;
3054 case RES_SOFT_LIMIT:
3055 return (u64)memcg->soft_limit * PAGE_SIZE;
3061 #ifdef CONFIG_MEMCG_KMEM
3062 static int memcg_online_kmem(struct mem_cgroup *memcg)
3066 if (cgroup_memory_nokmem)
3069 BUG_ON(memcg->kmemcg_id >= 0);
3070 BUG_ON(memcg->kmem_state);
3072 memcg_id = memcg_alloc_cache_id();
3076 static_branch_inc(&memcg_kmem_enabled_key);
3078 * A memory cgroup is considered kmem-online as soon as it gets
3079 * kmemcg_id. Setting the id after enabling static branching will
3080 * guarantee no one starts accounting before all call sites are
3083 memcg->kmemcg_id = memcg_id;
3084 memcg->kmem_state = KMEM_ONLINE;
3085 INIT_LIST_HEAD(&memcg->kmem_caches);
3090 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3092 struct cgroup_subsys_state *css;
3093 struct mem_cgroup *parent, *child;
3096 if (memcg->kmem_state != KMEM_ONLINE)
3099 * Clear the online state before clearing memcg_caches array
3100 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
3101 * guarantees that no cache will be created for this cgroup
3102 * after we are done (see memcg_create_kmem_cache()).
3104 memcg->kmem_state = KMEM_ALLOCATED;
3106 memcg_deactivate_kmem_caches(memcg);
3108 kmemcg_id = memcg->kmemcg_id;
3109 BUG_ON(kmemcg_id < 0);
3111 parent = parent_mem_cgroup(memcg);
3113 parent = root_mem_cgroup;
3116 * Change kmemcg_id of this cgroup and all its descendants to the
3117 * parent's id, and then move all entries from this cgroup's list_lrus
3118 * to ones of the parent. After we have finished, all list_lrus
3119 * corresponding to this cgroup are guaranteed to remain empty. The
3120 * ordering is imposed by list_lru_node->lock taken by
3121 * memcg_drain_all_list_lrus().
3123 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3124 css_for_each_descendant_pre(css, &memcg->css) {
3125 child = mem_cgroup_from_css(css);
3126 BUG_ON(child->kmemcg_id != kmemcg_id);
3127 child->kmemcg_id = parent->kmemcg_id;
3128 if (!memcg->use_hierarchy)
3133 memcg_drain_all_list_lrus(kmemcg_id, parent);
3135 memcg_free_cache_id(kmemcg_id);
3138 static void memcg_free_kmem(struct mem_cgroup *memcg)
3140 /* css_alloc() failed, offlining didn't happen */
3141 if (unlikely(memcg->kmem_state == KMEM_ONLINE))
3142 memcg_offline_kmem(memcg);
3144 if (memcg->kmem_state == KMEM_ALLOCATED) {
3145 memcg_destroy_kmem_caches(memcg);
3146 static_branch_dec(&memcg_kmem_enabled_key);
3147 WARN_ON(page_counter_read(&memcg->kmem));
3151 static int memcg_online_kmem(struct mem_cgroup *memcg)
3155 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3158 static void memcg_free_kmem(struct mem_cgroup *memcg)
3161 #endif /* CONFIG_MEMCG_KMEM */
3163 static int memcg_update_kmem_max(struct mem_cgroup *memcg,
3168 mutex_lock(&memcg_max_mutex);
3169 ret = page_counter_set_max(&memcg->kmem, max);
3170 mutex_unlock(&memcg_max_mutex);
3174 static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
3178 mutex_lock(&memcg_max_mutex);
3180 ret = page_counter_set_max(&memcg->tcpmem, max);
3184 if (!memcg->tcpmem_active) {
3186 * The active flag needs to be written after the static_key
3187 * update. This is what guarantees that the socket activation
3188 * function is the last one to run. See mem_cgroup_sk_alloc()
3189 * for details, and note that we don't mark any socket as
3190 * belonging to this memcg until that flag is up.
3192 * We need to do this, because static_keys will span multiple
3193 * sites, but we can't control their order. If we mark a socket
3194 * as accounted, but the accounting functions are not patched in
3195 * yet, we'll lose accounting.
3197 * We never race with the readers in mem_cgroup_sk_alloc(),
3198 * because when this value change, the code to process it is not
3201 static_branch_inc(&memcg_sockets_enabled_key);
3202 memcg->tcpmem_active = true;
3205 mutex_unlock(&memcg_max_mutex);
3210 * The user of this function is...
3213 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3214 char *buf, size_t nbytes, loff_t off)
3216 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3217 unsigned long nr_pages;
3220 buf = strstrip(buf);
3221 ret = page_counter_memparse(buf, "-1", &nr_pages);
3225 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3227 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3231 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3233 ret = mem_cgroup_resize_max(memcg, nr_pages, false);
3236 ret = mem_cgroup_resize_max(memcg, nr_pages, true);
3239 ret = memcg_update_kmem_max(memcg, nr_pages);
3242 ret = memcg_update_tcp_max(memcg, nr_pages);
3246 case RES_SOFT_LIMIT:
3247 memcg->soft_limit = nr_pages;
3251 return ret ?: nbytes;
3254 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3255 size_t nbytes, loff_t off)
3257 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3258 struct page_counter *counter;
3260 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3262 counter = &memcg->memory;
3265 counter = &memcg->memsw;
3268 counter = &memcg->kmem;
3271 counter = &memcg->tcpmem;
3277 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3279 page_counter_reset_watermark(counter);
3282 counter->failcnt = 0;
3291 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3294 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3298 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3299 struct cftype *cft, u64 val)
3301 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3303 if (val & ~MOVE_MASK)
3307 * No kind of locking is needed in here, because ->can_attach() will
3308 * check this value once in the beginning of the process, and then carry
3309 * on with stale data. This means that changes to this value will only
3310 * affect task migrations starting after the change.
3312 memcg->move_charge_at_immigrate = val;
3316 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3317 struct cftype *cft, u64 val)
3324 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3328 unsigned int lru_mask;
3331 static const struct numa_stat stats[] = {
3332 { "total", LRU_ALL },
3333 { "file", LRU_ALL_FILE },
3334 { "anon", LRU_ALL_ANON },
3335 { "unevictable", BIT(LRU_UNEVICTABLE) },
3337 const struct numa_stat *stat;
3340 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3342 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3343 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
3344 seq_printf(m, "%s=%lu", stat->name, nr);
3345 for_each_node_state(nid, N_MEMORY) {
3346 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
3348 seq_printf(m, " N%d=%lu", nid, nr);
3353 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3354 struct mem_cgroup *iter;
3357 for_each_mem_cgroup_tree(iter, memcg)
3358 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
3359 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
3360 for_each_node_state(nid, N_MEMORY) {
3362 for_each_mem_cgroup_tree(iter, memcg)
3363 nr += mem_cgroup_node_nr_lru_pages(
3364 iter, nid, stat->lru_mask);
3365 seq_printf(m, " N%d=%lu", nid, nr);
3372 #endif /* CONFIG_NUMA */
3374 /* Universal VM events cgroup1 shows, original sort order */
3375 static const unsigned int memcg1_events[] = {
3382 static const char *const memcg1_event_names[] = {
3389 static int memcg_stat_show(struct seq_file *m, void *v)
3391 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
3392 unsigned long memory, memsw;
3393 struct mem_cgroup *mi;
3395 struct accumulated_stats acc;
3397 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
3398 BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);
3400 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
3401 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
3403 seq_printf(m, "%s %lu\n", memcg1_stat_names[i],
3404 memcg_page_state(memcg, memcg1_stats[i]) *
3408 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
3409 seq_printf(m, "%s %lu\n", memcg1_event_names[i],
3410 memcg_sum_events(memcg, memcg1_events[i]));
3412 for (i = 0; i < NR_LRU_LISTS; i++)
3413 seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
3414 mem_cgroup_nr_lru_pages(memcg, BIT(i)) * PAGE_SIZE);
3416 /* Hierarchical information */
3417 memory = memsw = PAGE_COUNTER_MAX;
3418 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
3419 memory = min(memory, mi->memory.max);
3420 memsw = min(memsw, mi->memsw.max);
3422 seq_printf(m, "hierarchical_memory_limit %llu\n",
3423 (u64)memory * PAGE_SIZE);
3424 if (do_memsw_account())
3425 seq_printf(m, "hierarchical_memsw_limit %llu\n",
3426 (u64)memsw * PAGE_SIZE);
3428 memset(&acc, 0, sizeof(acc));
3429 acc.stats_size = ARRAY_SIZE(memcg1_stats);
3430 acc.stats_array = memcg1_stats;
3431 acc.events_size = ARRAY_SIZE(memcg1_events);
3432 acc.events_array = memcg1_events;
3433 accumulate_memcg_tree(memcg, &acc);
3435 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
3436 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
3438 seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
3439 (u64)acc.stat[i] * PAGE_SIZE);
3442 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
3443 seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
3444 (u64)acc.events[i]);
3446 for (i = 0; i < NR_LRU_LISTS; i++)
3447 seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
3448 (u64)acc.lru_pages[i] * PAGE_SIZE);
3450 #ifdef CONFIG_DEBUG_VM
3453 struct mem_cgroup_per_node *mz;
3454 struct zone_reclaim_stat *rstat;
3455 unsigned long recent_rotated[2] = {0, 0};
3456 unsigned long recent_scanned[2] = {0, 0};
3458 for_each_online_pgdat(pgdat) {
3459 mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
3460 rstat = &mz->lruvec.reclaim_stat;
3462 recent_rotated[0] += rstat->recent_rotated[0];
3463 recent_rotated[1] += rstat->recent_rotated[1];
3464 recent_scanned[0] += rstat->recent_scanned[0];
3465 recent_scanned[1] += rstat->recent_scanned[1];
3467 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
3468 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
3469 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
3470 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
3477 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
3480 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3482 return mem_cgroup_swappiness(memcg);
3485 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
3486 struct cftype *cft, u64 val)
3488 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3494 memcg->swappiness = val;
3496 vm_swappiness = val;
3501 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3503 struct mem_cgroup_threshold_ary *t;
3504 unsigned long usage;
3509 t = rcu_dereference(memcg->thresholds.primary);
3511 t = rcu_dereference(memcg->memsw_thresholds.primary);
3516 usage = mem_cgroup_usage(memcg, swap);
3519 * current_threshold points to threshold just below or equal to usage.
3520 * If it's not true, a threshold was crossed after last
3521 * call of __mem_cgroup_threshold().
3523 i = t->current_threshold;
3526 * Iterate backward over array of thresholds starting from
3527 * current_threshold and check if a threshold is crossed.
3528 * If none of thresholds below usage is crossed, we read
3529 * only one element of the array here.
3531 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3532 eventfd_signal(t->entries[i].eventfd, 1);
3534 /* i = current_threshold + 1 */
3538 * Iterate forward over array of thresholds starting from
3539 * current_threshold+1 and check if a threshold is crossed.
3540 * If none of thresholds above usage is crossed, we read
3541 * only one element of the array here.
3543 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3544 eventfd_signal(t->entries[i].eventfd, 1);
3546 /* Update current_threshold */
3547 t->current_threshold = i - 1;
3552 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3555 __mem_cgroup_threshold(memcg, false);
3556 if (do_memsw_account())
3557 __mem_cgroup_threshold(memcg, true);
3559 memcg = parent_mem_cgroup(memcg);
3563 static int compare_thresholds(const void *a, const void *b)
3565 const struct mem_cgroup_threshold *_a = a;
3566 const struct mem_cgroup_threshold *_b = b;
3568 if (_a->threshold > _b->threshold)
3571 if (_a->threshold < _b->threshold)
3577 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
3579 struct mem_cgroup_eventfd_list *ev;
3581 spin_lock(&memcg_oom_lock);
3583 list_for_each_entry(ev, &memcg->oom_notify, list)
3584 eventfd_signal(ev->eventfd, 1);
3586 spin_unlock(&memcg_oom_lock);
3590 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
3592 struct mem_cgroup *iter;
3594 for_each_mem_cgroup_tree(iter, memcg)
3595 mem_cgroup_oom_notify_cb(iter);
3598 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
3599 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
3601 struct mem_cgroup_thresholds *thresholds;
3602 struct mem_cgroup_threshold_ary *new;
3603 unsigned long threshold;
3604 unsigned long usage;
3607 ret = page_counter_memparse(args, "-1", &threshold);
3611 mutex_lock(&memcg->thresholds_lock);
3614 thresholds = &memcg->thresholds;
3615 usage = mem_cgroup_usage(memcg, false);
3616 } else if (type == _MEMSWAP) {
3617 thresholds = &memcg->memsw_thresholds;
3618 usage = mem_cgroup_usage(memcg, true);
3622 /* Check if a threshold crossed before adding a new one */
3623 if (thresholds->primary)
3624 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3626 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
3628 /* Allocate memory for new array of thresholds */
3629 new = kmalloc(sizeof(*new) + size * sizeof(struct mem_cgroup_threshold),
3637 /* Copy thresholds (if any) to new array */
3638 if (thresholds->primary) {
3639 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
3640 sizeof(struct mem_cgroup_threshold));
3643 /* Add new threshold */
3644 new->entries[size - 1].eventfd = eventfd;
3645 new->entries[size - 1].threshold = threshold;
3647 /* Sort thresholds. Registering of new threshold isn't time-critical */
3648 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
3649 compare_thresholds, NULL);
3651 /* Find current threshold */
3652 new->current_threshold = -1;
3653 for (i = 0; i < size; i++) {
3654 if (new->entries[i].threshold <= usage) {
3656 * new->current_threshold will not be used until
3657 * rcu_assign_pointer(), so it's safe to increment
3660 ++new->current_threshold;
3665 /* Free old spare buffer and save old primary buffer as spare */
3666 kfree(thresholds->spare);
3667 thresholds->spare = thresholds->primary;
3669 rcu_assign_pointer(thresholds->primary, new);
3671 /* To be sure that nobody uses thresholds */
3675 mutex_unlock(&memcg->thresholds_lock);
3680 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
3681 struct eventfd_ctx *eventfd, const char *args)
3683 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
3686 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
3687 struct eventfd_ctx *eventfd, const char *args)
3689 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
3692 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3693 struct eventfd_ctx *eventfd, enum res_type type)
3695 struct mem_cgroup_thresholds *thresholds;
3696 struct mem_cgroup_threshold_ary *new;
3697 unsigned long usage;
3700 mutex_lock(&memcg->thresholds_lock);
3703 thresholds = &memcg->thresholds;
3704 usage = mem_cgroup_usage(memcg, false);
3705 } else if (type == _MEMSWAP) {
3706 thresholds = &memcg->memsw_thresholds;
3707 usage = mem_cgroup_usage(memcg, true);
3711 if (!thresholds->primary)
3714 /* Check if a threshold crossed before removing */
3715 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
3717 /* Calculate new number of threshold */
3719 for (i = 0; i < thresholds->primary->size; i++) {
3720 if (thresholds->primary->entries[i].eventfd != eventfd)
3724 new = thresholds->spare;
3726 /* Set thresholds array to NULL if we don't have thresholds */
3735 /* Copy thresholds and find current threshold */
3736 new->current_threshold = -1;
3737 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
3738 if (thresholds->primary->entries[i].eventfd == eventfd)
3741 new->entries[j] = thresholds->primary->entries[i];
3742 if (new->entries[j].threshold <= usage) {
3744 * new->current_threshold will not be used
3745 * until rcu_assign_pointer(), so it's safe to increment
3748 ++new->current_threshold;
3754 /* Swap primary and spare array */
3755 thresholds->spare = thresholds->primary;
3757 rcu_assign_pointer(thresholds->primary, new);
3759 /* To be sure that nobody uses thresholds */
3762 /* If all events are unregistered, free the spare array */
3764 kfree(thresholds->spare);
3765 thresholds->spare = NULL;
3768 mutex_unlock(&memcg->thresholds_lock);
3771 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3772 struct eventfd_ctx *eventfd)
3774 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
3777 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
3778 struct eventfd_ctx *eventfd)
3780 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
3783 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
3784 struct eventfd_ctx *eventfd, const char *args)
3786 struct mem_cgroup_eventfd_list *event;
3788 event = kmalloc(sizeof(*event), GFP_KERNEL);
3792 spin_lock(&memcg_oom_lock);
3794 event->eventfd = eventfd;
3795 list_add(&event->list, &memcg->oom_notify);
3797 /* already in OOM ? */
3798 if (memcg->under_oom)
3799 eventfd_signal(eventfd, 1);
3800 spin_unlock(&memcg_oom_lock);
3805 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
3806 struct eventfd_ctx *eventfd)
3808 struct mem_cgroup_eventfd_list *ev, *tmp;
3810 spin_lock(&memcg_oom_lock);
3812 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
3813 if (ev->eventfd == eventfd) {
3814 list_del(&ev->list);
3819 spin_unlock(&memcg_oom_lock);
3822 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
3824 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(sf));
3826 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
3827 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
3828 seq_printf(sf, "oom_kill %lu\n",
3829 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
3833 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
3834 struct cftype *cft, u64 val)
3836 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3838 /* cannot set to root cgroup and only 0 and 1 are allowed */
3839 if (!css->parent || !((val == 0) || (val == 1)))
3842 memcg->oom_kill_disable = val;
3844 memcg_oom_recover(memcg);
3849 #ifdef CONFIG_CGROUP_WRITEBACK
3851 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
3853 return wb_domain_init(&memcg->cgwb_domain, gfp);
3856 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
3858 wb_domain_exit(&memcg->cgwb_domain);
3861 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
3863 wb_domain_size_changed(&memcg->cgwb_domain);
3866 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
3868 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
3870 if (!memcg->css.parent)
3873 return &memcg->cgwb_domain;
3877 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
3878 * @wb: bdi_writeback in question
3879 * @pfilepages: out parameter for number of file pages
3880 * @pheadroom: out parameter for number of allocatable pages according to memcg
3881 * @pdirty: out parameter for number of dirty pages
3882 * @pwriteback: out parameter for number of pages under writeback
3884 * Determine the numbers of file, headroom, dirty, and writeback pages in
3885 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
3886 * is a bit more involved.
3888 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
3889 * headroom is calculated as the lowest headroom of itself and the
3890 * ancestors. Note that this doesn't consider the actual amount of
3891 * available memory in the system. The caller should further cap
3892 * *@pheadroom accordingly.
3894 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
3895 unsigned long *pheadroom, unsigned long *pdirty,
3896 unsigned long *pwriteback)
3898 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
3899 struct mem_cgroup *parent;
3901 *pdirty = memcg_page_state(memcg, NR_FILE_DIRTY);
3903 /* this should eventually include NR_UNSTABLE_NFS */
3904 *pwriteback = memcg_page_state(memcg, NR_WRITEBACK);
3905 *pfilepages = mem_cgroup_nr_lru_pages(memcg, (1 << LRU_INACTIVE_FILE) |
3906 (1 << LRU_ACTIVE_FILE));
3907 *pheadroom = PAGE_COUNTER_MAX;
3909 while ((parent = parent_mem_cgroup(memcg))) {
3910 unsigned long ceiling = min(memcg->memory.max, memcg->high);
3911 unsigned long used = page_counter_read(&memcg->memory);
3913 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
3918 #else /* CONFIG_CGROUP_WRITEBACK */
3920 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
3925 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
3929 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
3933 #endif /* CONFIG_CGROUP_WRITEBACK */
3936 * DO NOT USE IN NEW FILES.
3938 * "cgroup.event_control" implementation.
3940 * This is way over-engineered. It tries to support fully configurable
3941 * events for each user. Such level of flexibility is completely
3942 * unnecessary especially in the light of the planned unified hierarchy.
3944 * Please deprecate this and replace with something simpler if at all
3949 * Unregister event and free resources.
3951 * Gets called from workqueue.
3953 static void memcg_event_remove(struct work_struct *work)
3955 struct mem_cgroup_event *event =
3956 container_of(work, struct mem_cgroup_event, remove);
3957 struct mem_cgroup *memcg = event->memcg;
3959 remove_wait_queue(event->wqh, &event->wait);
3961 event->unregister_event(memcg, event->eventfd);
3963 /* Notify userspace the event is going away. */
3964 eventfd_signal(event->eventfd, 1);
3966 eventfd_ctx_put(event->eventfd);
3968 css_put(&memcg->css);
3972 * Gets called on EPOLLHUP on eventfd when user closes it.
3974 * Called with wqh->lock held and interrupts disabled.
3976 static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
3977 int sync, void *key)
3979 struct mem_cgroup_event *event =
3980 container_of(wait, struct mem_cgroup_event, wait);
3981 struct mem_cgroup *memcg = event->memcg;
3982 __poll_t flags = key_to_poll(key);
3984 if (flags & EPOLLHUP) {
3986 * If the event has been detached at cgroup removal, we
3987 * can simply return knowing the other side will cleanup
3990 * We can't race against event freeing since the other
3991 * side will require wqh->lock via remove_wait_queue(),
3994 spin_lock(&memcg->event_list_lock);
3995 if (!list_empty(&event->list)) {
3996 list_del_init(&event->list);
3998 * We are in atomic context, but cgroup_event_remove()
3999 * may sleep, so we have to call it in workqueue.
4001 schedule_work(&event->remove);
4003 spin_unlock(&memcg->event_list_lock);
4009 static void memcg_event_ptable_queue_proc(struct file *file,
4010 wait_queue_head_t *wqh, poll_table *pt)
4012 struct mem_cgroup_event *event =
4013 container_of(pt, struct mem_cgroup_event, pt);
4016 add_wait_queue(wqh, &event->wait);
4020 * DO NOT USE IN NEW FILES.
4022 * Parse input and register new cgroup event handler.
4024 * Input must be in format '<event_fd> <control_fd> <args>'.
4025 * Interpretation of args is defined by control file implementation.
4027 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4028 char *buf, size_t nbytes, loff_t off)
4030 struct cgroup_subsys_state *css = of_css(of);
4031 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4032 struct mem_cgroup_event *event;
4033 struct cgroup_subsys_state *cfile_css;
4034 unsigned int efd, cfd;
4041 buf = strstrip(buf);
4043 efd = simple_strtoul(buf, &endp, 10);
4048 cfd = simple_strtoul(buf, &endp, 10);
4049 if ((*endp != ' ') && (*endp != '\0'))
4053 event = kzalloc(sizeof(*event), GFP_KERNEL);
4057 event->memcg = memcg;
4058 INIT_LIST_HEAD(&event->list);
4059 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4060 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4061 INIT_WORK(&event->remove, memcg_event_remove);
4069 event->eventfd = eventfd_ctx_fileget(efile.file);
4070 if (IS_ERR(event->eventfd)) {
4071 ret = PTR_ERR(event->eventfd);
4078 goto out_put_eventfd;
4081 /* the process need read permission on control file */
4082 /* AV: shouldn't we check that it's been opened for read instead? */
4083 ret = inode_permission(file_inode(cfile.file), MAY_READ);
4088 * Determine the event callbacks and set them in @event. This used
4089 * to be done via struct cftype but cgroup core no longer knows
4090 * about these events. The following is crude but the whole thing
4091 * is for compatibility anyway.
4093 * DO NOT ADD NEW FILES.
4095 name = cfile.file->f_path.dentry->d_name.name;
4097 if (!strcmp(name, "memory.usage_in_bytes")) {
4098 event->register_event = mem_cgroup_usage_register_event;
4099 event->unregister_event = mem_cgroup_usage_unregister_event;
4100 } else if (!strcmp(name, "memory.oom_control")) {
4101 event->register_event = mem_cgroup_oom_register_event;
4102 event->unregister_event = mem_cgroup_oom_unregister_event;
4103 } else if (!strcmp(name, "memory.pressure_level")) {
4104 event->register_event = vmpressure_register_event;
4105 event->unregister_event = vmpressure_unregister_event;
4106 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4107 event->register_event = memsw_cgroup_usage_register_event;
4108 event->unregister_event = memsw_cgroup_usage_unregister_event;
4115 * Verify @cfile should belong to @css. Also, remaining events are
4116 * automatically removed on cgroup destruction but the removal is
4117 * asynchronous, so take an extra ref on @css.
4119 cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
4120 &memory_cgrp_subsys);
4122 if (IS_ERR(cfile_css))
4124 if (cfile_css != css) {
4129 ret = event->register_event(memcg, event->eventfd, buf);
4133 vfs_poll(efile.file, &event->pt);
4135 spin_lock(&memcg->event_list_lock);
4136 list_add(&event->list, &memcg->event_list);
4137 spin_unlock(&memcg->event_list_lock);
4149 eventfd_ctx_put(event->eventfd);
4158 static struct cftype mem_cgroup_legacy_files[] = {
4160 .name = "usage_in_bytes",
4161 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4162 .read_u64 = mem_cgroup_read_u64,
4165 .name = "max_usage_in_bytes",
4166 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4167 .write = mem_cgroup_reset,
4168 .read_u64 = mem_cgroup_read_u64,
4171 .name = "limit_in_bytes",
4172 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4173 .write = mem_cgroup_write,
4174 .read_u64 = mem_cgroup_read_u64,
4177 .name = "soft_limit_in_bytes",
4178 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4179 .write = mem_cgroup_write,
4180 .read_u64 = mem_cgroup_read_u64,
4184 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4185 .write = mem_cgroup_reset,
4186 .read_u64 = mem_cgroup_read_u64,
4190 .seq_show = memcg_stat_show,
4193 .name = "force_empty",
4194 .write = mem_cgroup_force_empty_write,
4197 .name = "use_hierarchy",
4198 .write_u64 = mem_cgroup_hierarchy_write,
4199 .read_u64 = mem_cgroup_hierarchy_read,
4202 .name = "cgroup.event_control", /* XXX: for compat */
4203 .write = memcg_write_event_control,
4204 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
4207 .name = "swappiness",
4208 .read_u64 = mem_cgroup_swappiness_read,
4209 .write_u64 = mem_cgroup_swappiness_write,
4212 .name = "move_charge_at_immigrate",
4213 .read_u64 = mem_cgroup_move_charge_read,
4214 .write_u64 = mem_cgroup_move_charge_write,
4217 .name = "oom_control",
4218 .seq_show = mem_cgroup_oom_control_read,
4219 .write_u64 = mem_cgroup_oom_control_write,
4220 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4223 .name = "pressure_level",
4227 .name = "numa_stat",
4228 .seq_show = memcg_numa_stat_show,
4232 .name = "kmem.limit_in_bytes",
4233 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4234 .write = mem_cgroup_write,
4235 .read_u64 = mem_cgroup_read_u64,
4238 .name = "kmem.usage_in_bytes",
4239 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4240 .read_u64 = mem_cgroup_read_u64,
4243 .name = "kmem.failcnt",
4244 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4245 .write = mem_cgroup_reset,
4246 .read_u64 = mem_cgroup_read_u64,
4249 .name = "kmem.max_usage_in_bytes",
4250 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4251 .write = mem_cgroup_reset,
4252 .read_u64 = mem_cgroup_read_u64,
4254 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
4256 .name = "kmem.slabinfo",
4257 .seq_start = memcg_slab_start,
4258 .seq_next = memcg_slab_next,
4259 .seq_stop = memcg_slab_stop,
4260 .seq_show = memcg_slab_show,
4264 .name = "kmem.tcp.limit_in_bytes",
4265 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
4266 .write = mem_cgroup_write,
4267 .read_u64 = mem_cgroup_read_u64,
4270 .name = "kmem.tcp.usage_in_bytes",
4271 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
4272 .read_u64 = mem_cgroup_read_u64,
4275 .name = "kmem.tcp.failcnt",
4276 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
4277 .write = mem_cgroup_reset,
4278 .read_u64 = mem_cgroup_read_u64,
4281 .name = "kmem.tcp.max_usage_in_bytes",
4282 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
4283 .write = mem_cgroup_reset,
4284 .read_u64 = mem_cgroup_read_u64,
4286 { }, /* terminate */
4290 * Private memory cgroup IDR
4292 * Swap-out records and page cache shadow entries need to store memcg
4293 * references in constrained space, so we maintain an ID space that is
4294 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4295 * memory-controlled cgroups to 64k.
4297 * However, there usually are many references to the oflline CSS after
4298 * the cgroup has been destroyed, such as page cache or reclaimable
4299 * slab objects, that don't need to hang on to the ID. We want to keep
4300 * those dead CSS from occupying IDs, or we might quickly exhaust the
4301 * relatively small ID space and prevent the creation of new cgroups
4302 * even when there are much fewer than 64k cgroups - possibly none.
4304 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4305 * be freed and recycled when it's no longer needed, which is usually
4306 * when the CSS is offlined.
4308 * The only exception to that are records of swapped out tmpfs/shmem
4309 * pages that need to be attributed to live ancestors on swapin. But
4310 * those references are manageable from userspace.
4313 static DEFINE_IDR(mem_cgroup_idr);
4315 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
4317 if (memcg->id.id > 0) {
4318 idr_remove(&mem_cgroup_idr, memcg->id.id);
4323 static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
4325 refcount_add(n, &memcg->id.ref);
4328 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
4330 if (refcount_sub_and_test(n, &memcg->id.ref)) {
4331 mem_cgroup_id_remove(memcg);
4333 /* Memcg ID pins CSS */
4334 css_put(&memcg->css);
4338 static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
4340 mem_cgroup_id_get_many(memcg, 1);
4343 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
4345 mem_cgroup_id_put_many(memcg, 1);
4349 * mem_cgroup_from_id - look up a memcg from a memcg id
4350 * @id: the memcg id to look up
4352 * Caller must hold rcu_read_lock().
4354 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
4356 WARN_ON_ONCE(!rcu_read_lock_held());
4357 return idr_find(&mem_cgroup_idr, id);
4360 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4362 struct mem_cgroup_per_node *pn;
4365 * This routine is called against possible nodes.
4366 * But it's BUG to call kmalloc() against offline node.
4368 * TODO: this routine can waste much memory for nodes which will
4369 * never be onlined. It's better to use memory hotplug callback
4372 if (!node_state(node, N_NORMAL_MEMORY))
4374 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4378 pn->lruvec_stat_cpu = alloc_percpu(struct lruvec_stat);
4379 if (!pn->lruvec_stat_cpu) {
4384 lruvec_init(&pn->lruvec);
4385 pn->usage_in_excess = 0;
4386 pn->on_tree = false;
4389 memcg->nodeinfo[node] = pn;
4393 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4395 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
4400 free_percpu(pn->lruvec_stat_cpu);
4404 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4409 free_mem_cgroup_per_node_info(memcg, node);
4410 free_percpu(memcg->stat_cpu);
4414 static void mem_cgroup_free(struct mem_cgroup *memcg)
4416 memcg_wb_domain_exit(memcg);
4417 __mem_cgroup_free(memcg);
4420 static struct mem_cgroup *mem_cgroup_alloc(void)
4422 struct mem_cgroup *memcg;
4426 size = sizeof(struct mem_cgroup);
4427 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
4429 memcg = kzalloc(size, GFP_KERNEL);
4433 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
4434 1, MEM_CGROUP_ID_MAX,
4436 if (memcg->id.id < 0)
4439 memcg->stat_cpu = alloc_percpu(struct mem_cgroup_stat_cpu);
4440 if (!memcg->stat_cpu)
4444 if (alloc_mem_cgroup_per_node_info(memcg, node))
4447 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
4450 INIT_WORK(&memcg->high_work, high_work_func);
4451 memcg->last_scanned_node = MAX_NUMNODES;
4452 INIT_LIST_HEAD(&memcg->oom_notify);
4453 mutex_init(&memcg->thresholds_lock);
4454 spin_lock_init(&memcg->move_lock);
4455 vmpressure_init(&memcg->vmpressure);
4456 INIT_LIST_HEAD(&memcg->event_list);
4457 spin_lock_init(&memcg->event_list_lock);
4458 memcg->socket_pressure = jiffies;
4459 #ifdef CONFIG_MEMCG_KMEM
4460 memcg->kmemcg_id = -1;
4462 #ifdef CONFIG_CGROUP_WRITEBACK
4463 INIT_LIST_HEAD(&memcg->cgwb_list);
4465 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
4468 mem_cgroup_id_remove(memcg);
4469 __mem_cgroup_free(memcg);
4473 static struct cgroup_subsys_state * __ref
4474 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
4476 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
4477 struct mem_cgroup *memcg;
4478 long error = -ENOMEM;
4480 memcg = mem_cgroup_alloc();
4482 return ERR_PTR(error);
4484 memcg->high = PAGE_COUNTER_MAX;
4485 memcg->soft_limit = PAGE_COUNTER_MAX;
4487 memcg->swappiness = mem_cgroup_swappiness(parent);
4488 memcg->oom_kill_disable = parent->oom_kill_disable;
4490 if (parent && parent->use_hierarchy) {
4491 memcg->use_hierarchy = true;
4492 page_counter_init(&memcg->memory, &parent->memory);
4493 page_counter_init(&memcg->swap, &parent->swap);
4494 page_counter_init(&memcg->memsw, &parent->memsw);
4495 page_counter_init(&memcg->kmem, &parent->kmem);
4496 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
4498 page_counter_init(&memcg->memory, NULL);
4499 page_counter_init(&memcg->swap, NULL);
4500 page_counter_init(&memcg->memsw, NULL);
4501 page_counter_init(&memcg->kmem, NULL);
4502 page_counter_init(&memcg->tcpmem, NULL);
4504 * Deeper hierachy with use_hierarchy == false doesn't make
4505 * much sense so let cgroup subsystem know about this
4506 * unfortunate state in our controller.
4508 if (parent != root_mem_cgroup)
4509 memory_cgrp_subsys.broken_hierarchy = true;
4512 /* The following stuff does not apply to the root */
4514 root_mem_cgroup = memcg;
4518 error = memcg_online_kmem(memcg);
4522 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
4523 static_branch_inc(&memcg_sockets_enabled_key);
4527 mem_cgroup_id_remove(memcg);
4528 mem_cgroup_free(memcg);
4529 return ERR_PTR(-ENOMEM);
4532 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
4534 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4537 * A memcg must be visible for memcg_expand_shrinker_maps()
4538 * by the time the maps are allocated. So, we allocate maps
4539 * here, when for_each_mem_cgroup() can't skip it.
4541 if (memcg_alloc_shrinker_maps(memcg)) {
4542 mem_cgroup_id_remove(memcg);
4546 /* Online state pins memcg ID, memcg ID pins CSS */
4547 refcount_set(&memcg->id.ref, 1);
4552 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
4554 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4555 struct mem_cgroup_event *event, *tmp;
4558 * Unregister events and notify userspace.
4559 * Notify userspace about cgroup removing only after rmdir of cgroup
4560 * directory to avoid race between userspace and kernelspace.
4562 spin_lock(&memcg->event_list_lock);
4563 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
4564 list_del_init(&event->list);
4565 schedule_work(&event->remove);
4567 spin_unlock(&memcg->event_list_lock);
4569 page_counter_set_min(&memcg->memory, 0);
4570 page_counter_set_low(&memcg->memory, 0);
4572 memcg_offline_kmem(memcg);
4573 wb_memcg_offline(memcg);
4575 drain_all_stock(memcg);
4577 mem_cgroup_id_put(memcg);
4580 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
4582 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4584 invalidate_reclaim_iterators(memcg);
4587 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
4589 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4591 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
4592 static_branch_dec(&memcg_sockets_enabled_key);
4594 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
4595 static_branch_dec(&memcg_sockets_enabled_key);
4597 vmpressure_cleanup(&memcg->vmpressure);
4598 cancel_work_sync(&memcg->high_work);
4599 mem_cgroup_remove_from_trees(memcg);
4600 memcg_free_shrinker_maps(memcg);
4601 memcg_free_kmem(memcg);
4602 mem_cgroup_free(memcg);
4606 * mem_cgroup_css_reset - reset the states of a mem_cgroup
4607 * @css: the target css
4609 * Reset the states of the mem_cgroup associated with @css. This is
4610 * invoked when the userland requests disabling on the default hierarchy
4611 * but the memcg is pinned through dependency. The memcg should stop
4612 * applying policies and should revert to the vanilla state as it may be
4613 * made visible again.
4615 * The current implementation only resets the essential configurations.
4616 * This needs to be expanded to cover all the visible parts.
4618 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
4620 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4622 page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
4623 page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
4624 page_counter_set_max(&memcg->memsw, PAGE_COUNTER_MAX);
4625 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
4626 page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
4627 page_counter_set_min(&memcg->memory, 0);
4628 page_counter_set_low(&memcg->memory, 0);
4629 memcg->high = PAGE_COUNTER_MAX;
4630 memcg->soft_limit = PAGE_COUNTER_MAX;
4631 memcg_wb_domain_size_changed(memcg);
4635 /* Handlers for move charge at task migration. */
4636 static int mem_cgroup_do_precharge(unsigned long count)
4640 /* Try a single bulk charge without reclaim first, kswapd may wake */
4641 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
4643 mc.precharge += count;
4647 /* Try charges one by one with reclaim, but do not retry */
4649 ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
4663 enum mc_target_type {
4670 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
4671 unsigned long addr, pte_t ptent)
4673 struct page *page = _vm_normal_page(vma, addr, ptent, true);
4675 if (!page || !page_mapped(page))
4677 if (PageAnon(page)) {
4678 if (!(mc.flags & MOVE_ANON))
4681 if (!(mc.flags & MOVE_FILE))
4684 if (!get_page_unless_zero(page))
4690 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
4691 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4692 pte_t ptent, swp_entry_t *entry)
4694 struct page *page = NULL;
4695 swp_entry_t ent = pte_to_swp_entry(ptent);
4697 if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent))
4701 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
4702 * a device and because they are not accessible by CPU they are store
4703 * as special swap entry in the CPU page table.
4705 if (is_device_private_entry(ent)) {
4706 page = device_private_entry_to_page(ent);
4708 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
4709 * a refcount of 1 when free (unlike normal page)
4711 if (!page_ref_add_unless(page, 1, 1))
4717 * Because lookup_swap_cache() updates some statistics counter,
4718 * we call find_get_page() with swapper_space directly.
4720 page = find_get_page(swap_address_space(ent), swp_offset(ent));
4721 if (do_memsw_account())
4722 entry->val = ent.val;
4727 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
4728 pte_t ptent, swp_entry_t *entry)
4734 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
4735 unsigned long addr, pte_t ptent, swp_entry_t *entry)
4737 struct page *page = NULL;
4738 struct address_space *mapping;
4741 if (!vma->vm_file) /* anonymous vma */
4743 if (!(mc.flags & MOVE_FILE))
4746 mapping = vma->vm_file->f_mapping;
4747 pgoff = linear_page_index(vma, addr);
4749 /* page is moved even if it's not RSS of this task(page-faulted). */
4751 /* shmem/tmpfs may report page out on swap: account for that too. */
4752 if (shmem_mapping(mapping)) {
4753 page = find_get_entry(mapping, pgoff);
4754 if (xa_is_value(page)) {
4755 swp_entry_t swp = radix_to_swp_entry(page);
4756 if (do_memsw_account())
4758 page = find_get_page(swap_address_space(swp),
4762 page = find_get_page(mapping, pgoff);
4764 page = find_get_page(mapping, pgoff);
4770 * mem_cgroup_move_account - move account of the page
4772 * @compound: charge the page as compound or small page
4773 * @from: mem_cgroup which the page is moved from.
4774 * @to: mem_cgroup which the page is moved to. @from != @to.
4776 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
4778 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
4781 static int mem_cgroup_move_account(struct page *page,
4783 struct mem_cgroup *from,
4784 struct mem_cgroup *to)
4786 unsigned long flags;
4787 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
4791 VM_BUG_ON(from == to);
4792 VM_BUG_ON_PAGE(PageLRU(page), page);
4793 VM_BUG_ON(compound && !PageTransHuge(page));
4796 * Prevent mem_cgroup_migrate() from looking at
4797 * page->mem_cgroup of its source page while we change it.
4800 if (!trylock_page(page))
4804 if (page->mem_cgroup != from)
4807 anon = PageAnon(page);
4809 spin_lock_irqsave(&from->move_lock, flags);
4811 if (!anon && page_mapped(page)) {
4812 __mod_memcg_state(from, NR_FILE_MAPPED, -nr_pages);
4813 __mod_memcg_state(to, NR_FILE_MAPPED, nr_pages);
4817 * move_lock grabbed above and caller set from->moving_account, so
4818 * mod_memcg_page_state will serialize updates to PageDirty.
4819 * So mapping should be stable for dirty pages.
4821 if (!anon && PageDirty(page)) {
4822 struct address_space *mapping = page_mapping(page);
4824 if (mapping_cap_account_dirty(mapping)) {
4825 __mod_memcg_state(from, NR_FILE_DIRTY, -nr_pages);
4826 __mod_memcg_state(to, NR_FILE_DIRTY, nr_pages);
4830 if (PageWriteback(page)) {
4831 __mod_memcg_state(from, NR_WRITEBACK, -nr_pages);
4832 __mod_memcg_state(to, NR_WRITEBACK, nr_pages);
4836 * It is safe to change page->mem_cgroup here because the page
4837 * is referenced, charged, and isolated - we can't race with
4838 * uncharging, charging, migration, or LRU putback.
4841 /* caller should have done css_get */
4842 page->mem_cgroup = to;
4843 spin_unlock_irqrestore(&from->move_lock, flags);
4847 local_irq_disable();
4848 mem_cgroup_charge_statistics(to, page, compound, nr_pages);
4849 memcg_check_events(to, page);
4850 mem_cgroup_charge_statistics(from, page, compound, -nr_pages);
4851 memcg_check_events(from, page);
4860 * get_mctgt_type - get target type of moving charge
4861 * @vma: the vma the pte to be checked belongs
4862 * @addr: the address corresponding to the pte to be checked
4863 * @ptent: the pte to be checked
4864 * @target: the pointer the target page or swap ent will be stored(can be NULL)
4867 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
4868 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
4869 * move charge. if @target is not NULL, the page is stored in target->page
4870 * with extra refcnt got(Callers should handle it).
4871 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
4872 * target for charge migration. if @target is not NULL, the entry is stored
4874 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PUBLIC
4875 * or MEMORY_DEVICE_PRIVATE (so ZONE_DEVICE page and thus not on the lru).
4876 * For now we such page is charge like a regular page would be as for all
4877 * intent and purposes it is just special memory taking the place of a
4880 * See Documentations/vm/hmm.txt and include/linux/hmm.h
4882 * Called with pte lock held.
4885 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
4886 unsigned long addr, pte_t ptent, union mc_target *target)
4888 struct page *page = NULL;
4889 enum mc_target_type ret = MC_TARGET_NONE;
4890 swp_entry_t ent = { .val = 0 };
4892 if (pte_present(ptent))
4893 page = mc_handle_present_pte(vma, addr, ptent);
4894 else if (is_swap_pte(ptent))
4895 page = mc_handle_swap_pte(vma, ptent, &ent);
4896 else if (pte_none(ptent))
4897 page = mc_handle_file_pte(vma, addr, ptent, &ent);
4899 if (!page && !ent.val)
4903 * Do only loose check w/o serialization.
4904 * mem_cgroup_move_account() checks the page is valid or
4905 * not under LRU exclusion.
4907 if (page->mem_cgroup == mc.from) {
4908 ret = MC_TARGET_PAGE;
4909 if (is_device_private_page(page) ||
4910 is_device_public_page(page))
4911 ret = MC_TARGET_DEVICE;
4913 target->page = page;
4915 if (!ret || !target)
4919 * There is a swap entry and a page doesn't exist or isn't charged.
4920 * But we cannot move a tail-page in a THP.
4922 if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
4923 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
4924 ret = MC_TARGET_SWAP;
4931 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
4933 * We don't consider PMD mapped swapping or file mapped pages because THP does
4934 * not support them for now.
4935 * Caller should make sure that pmd_trans_huge(pmd) is true.
4937 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
4938 unsigned long addr, pmd_t pmd, union mc_target *target)
4940 struct page *page = NULL;
4941 enum mc_target_type ret = MC_TARGET_NONE;
4943 if (unlikely(is_swap_pmd(pmd))) {
4944 VM_BUG_ON(thp_migration_supported() &&
4945 !is_pmd_migration_entry(pmd));
4948 page = pmd_page(pmd);
4949 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
4950 if (!(mc.flags & MOVE_ANON))
4952 if (page->mem_cgroup == mc.from) {
4953 ret = MC_TARGET_PAGE;
4956 target->page = page;
4962 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
4963 unsigned long addr, pmd_t pmd, union mc_target *target)
4965 return MC_TARGET_NONE;
4969 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
4970 unsigned long addr, unsigned long end,
4971 struct mm_walk *walk)
4973 struct vm_area_struct *vma = walk->vma;
4977 ptl = pmd_trans_huge_lock(pmd, vma);
4980 * Note their can not be MC_TARGET_DEVICE for now as we do not
4981 * support transparent huge page with MEMORY_DEVICE_PUBLIC or
4982 * MEMORY_DEVICE_PRIVATE but this might change.
4984 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
4985 mc.precharge += HPAGE_PMD_NR;
4990 if (pmd_trans_unstable(pmd))
4992 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
4993 for (; addr != end; pte++, addr += PAGE_SIZE)
4994 if (get_mctgt_type(vma, addr, *pte, NULL))
4995 mc.precharge++; /* increment precharge temporarily */
4996 pte_unmap_unlock(pte - 1, ptl);
5002 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5004 unsigned long precharge;
5006 struct mm_walk mem_cgroup_count_precharge_walk = {
5007 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5010 down_read(&mm->mmap_sem);
5011 walk_page_range(0, mm->highest_vm_end,
5012 &mem_cgroup_count_precharge_walk);
5013 up_read(&mm->mmap_sem);
5015 precharge = mc.precharge;
5021 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5023 unsigned long precharge = mem_cgroup_count_precharge(mm);
5025 VM_BUG_ON(mc.moving_task);
5026 mc.moving_task = current;
5027 return mem_cgroup_do_precharge(precharge);
5030 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5031 static void __mem_cgroup_clear_mc(void)
5033 struct mem_cgroup *from = mc.from;
5034 struct mem_cgroup *to = mc.to;
5036 /* we must uncharge all the leftover precharges from mc.to */
5038 cancel_charge(mc.to, mc.precharge);
5042 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5043 * we must uncharge here.
5045 if (mc.moved_charge) {
5046 cancel_charge(mc.from, mc.moved_charge);
5047 mc.moved_charge = 0;
5049 /* we must fixup refcnts and charges */
5050 if (mc.moved_swap) {
5051 /* uncharge swap account from the old cgroup */
5052 if (!mem_cgroup_is_root(mc.from))
5053 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5055 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
5058 * we charged both to->memory and to->memsw, so we
5059 * should uncharge to->memory.
5061 if (!mem_cgroup_is_root(mc.to))
5062 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5064 mem_cgroup_id_get_many(mc.to, mc.moved_swap);
5065 css_put_many(&mc.to->css, mc.moved_swap);
5069 memcg_oom_recover(from);
5070 memcg_oom_recover(to);
5071 wake_up_all(&mc.waitq);
5074 static void mem_cgroup_clear_mc(void)
5076 struct mm_struct *mm = mc.mm;
5079 * we must clear moving_task before waking up waiters at the end of
5082 mc.moving_task = NULL;
5083 __mem_cgroup_clear_mc();
5084 spin_lock(&mc.lock);
5088 spin_unlock(&mc.lock);
5093 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5095 struct cgroup_subsys_state *css;
5096 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
5097 struct mem_cgroup *from;
5098 struct task_struct *leader, *p;
5099 struct mm_struct *mm;
5100 unsigned long move_flags;
5103 /* charge immigration isn't supported on the default hierarchy */
5104 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5108 * Multi-process migrations only happen on the default hierarchy
5109 * where charge immigration is not used. Perform charge
5110 * immigration if @tset contains a leader and whine if there are
5114 cgroup_taskset_for_each_leader(leader, css, tset) {
5117 memcg = mem_cgroup_from_css(css);
5123 * We are now commited to this value whatever it is. Changes in this
5124 * tunable will only affect upcoming migrations, not the current one.
5125 * So we need to save it, and keep it going.
5127 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
5131 from = mem_cgroup_from_task(p);
5133 VM_BUG_ON(from == memcg);
5135 mm = get_task_mm(p);
5138 /* We move charges only when we move a owner of the mm */
5139 if (mm->owner == p) {
5142 VM_BUG_ON(mc.precharge);
5143 VM_BUG_ON(mc.moved_charge);
5144 VM_BUG_ON(mc.moved_swap);
5146 spin_lock(&mc.lock);
5150 mc.flags = move_flags;
5151 spin_unlock(&mc.lock);
5152 /* We set mc.moving_task later */
5154 ret = mem_cgroup_precharge_mc(mm);
5156 mem_cgroup_clear_mc();
5163 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
5166 mem_cgroup_clear_mc();
5169 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5170 unsigned long addr, unsigned long end,
5171 struct mm_walk *walk)
5174 struct vm_area_struct *vma = walk->vma;
5177 enum mc_target_type target_type;
5178 union mc_target target;
5181 ptl = pmd_trans_huge_lock(pmd, vma);
5183 if (mc.precharge < HPAGE_PMD_NR) {
5187 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5188 if (target_type == MC_TARGET_PAGE) {
5190 if (!isolate_lru_page(page)) {
5191 if (!mem_cgroup_move_account(page, true,
5193 mc.precharge -= HPAGE_PMD_NR;
5194 mc.moved_charge += HPAGE_PMD_NR;
5196 putback_lru_page(page);
5199 } else if (target_type == MC_TARGET_DEVICE) {
5201 if (!mem_cgroup_move_account(page, true,
5203 mc.precharge -= HPAGE_PMD_NR;
5204 mc.moved_charge += HPAGE_PMD_NR;
5212 if (pmd_trans_unstable(pmd))
5215 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5216 for (; addr != end; addr += PAGE_SIZE) {
5217 pte_t ptent = *(pte++);
5218 bool device = false;
5224 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5225 case MC_TARGET_DEVICE:
5228 case MC_TARGET_PAGE:
5231 * We can have a part of the split pmd here. Moving it
5232 * can be done but it would be too convoluted so simply
5233 * ignore such a partial THP and keep it in original
5234 * memcg. There should be somebody mapping the head.
5236 if (PageTransCompound(page))
5238 if (!device && isolate_lru_page(page))
5240 if (!mem_cgroup_move_account(page, false,
5243 /* we uncharge from mc.from later. */
5247 putback_lru_page(page);
5248 put: /* get_mctgt_type() gets the page */
5251 case MC_TARGET_SWAP:
5253 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5255 /* we fixup refcnts and charges later. */
5263 pte_unmap_unlock(pte - 1, ptl);
5268 * We have consumed all precharges we got in can_attach().
5269 * We try charge one by one, but don't do any additional
5270 * charges to mc.to if we have failed in charge once in attach()
5273 ret = mem_cgroup_do_precharge(1);
5281 static void mem_cgroup_move_charge(void)
5283 struct mm_walk mem_cgroup_move_charge_walk = {
5284 .pmd_entry = mem_cgroup_move_charge_pte_range,
5288 lru_add_drain_all();
5290 * Signal lock_page_memcg() to take the memcg's move_lock
5291 * while we're moving its pages to another memcg. Then wait
5292 * for already started RCU-only updates to finish.
5294 atomic_inc(&mc.from->moving_account);
5297 if (unlikely(!down_read_trylock(&mc.mm->mmap_sem))) {
5299 * Someone who are holding the mmap_sem might be waiting in
5300 * waitq. So we cancel all extra charges, wake up all waiters,
5301 * and retry. Because we cancel precharges, we might not be able
5302 * to move enough charges, but moving charge is a best-effort
5303 * feature anyway, so it wouldn't be a big problem.
5305 __mem_cgroup_clear_mc();
5310 * When we have consumed all precharges and failed in doing
5311 * additional charge, the page walk just aborts.
5313 walk_page_range(0, mc.mm->highest_vm_end, &mem_cgroup_move_charge_walk);
5315 up_read(&mc.mm->mmap_sem);
5316 atomic_dec(&mc.from->moving_account);
5319 static void mem_cgroup_move_task(void)
5322 mem_cgroup_move_charge();
5323 mem_cgroup_clear_mc();
5326 #else /* !CONFIG_MMU */
5327 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5331 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
5334 static void mem_cgroup_move_task(void)
5340 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5341 * to verify whether we're attached to the default hierarchy on each mount
5344 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
5347 * use_hierarchy is forced on the default hierarchy. cgroup core
5348 * guarantees that @root doesn't have any children, so turning it
5349 * on for the root memcg is enough.
5351 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5352 root_mem_cgroup->use_hierarchy = true;
5354 root_mem_cgroup->use_hierarchy = false;
5357 static u64 memory_current_read(struct cgroup_subsys_state *css,
5360 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5362 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
5365 static int memory_min_show(struct seq_file *m, void *v)
5367 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5368 unsigned long min = READ_ONCE(memcg->memory.min);
5370 if (min == PAGE_COUNTER_MAX)
5371 seq_puts(m, "max\n");
5373 seq_printf(m, "%llu\n", (u64)min * PAGE_SIZE);
5378 static ssize_t memory_min_write(struct kernfs_open_file *of,
5379 char *buf, size_t nbytes, loff_t off)
5381 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5385 buf = strstrip(buf);
5386 err = page_counter_memparse(buf, "max", &min);
5390 page_counter_set_min(&memcg->memory, min);
5395 static int memory_low_show(struct seq_file *m, void *v)
5397 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5398 unsigned long low = READ_ONCE(memcg->memory.low);
5400 if (low == PAGE_COUNTER_MAX)
5401 seq_puts(m, "max\n");
5403 seq_printf(m, "%llu\n", (u64)low * PAGE_SIZE);
5408 static ssize_t memory_low_write(struct kernfs_open_file *of,
5409 char *buf, size_t nbytes, loff_t off)
5411 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5415 buf = strstrip(buf);
5416 err = page_counter_memparse(buf, "max", &low);
5420 page_counter_set_low(&memcg->memory, low);
5425 static int memory_high_show(struct seq_file *m, void *v)
5427 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5428 unsigned long high = READ_ONCE(memcg->high);
5430 if (high == PAGE_COUNTER_MAX)
5431 seq_puts(m, "max\n");
5433 seq_printf(m, "%llu\n", (u64)high * PAGE_SIZE);
5438 static ssize_t memory_high_write(struct kernfs_open_file *of,
5439 char *buf, size_t nbytes, loff_t off)
5441 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5442 unsigned long nr_pages;
5446 buf = strstrip(buf);
5447 err = page_counter_memparse(buf, "max", &high);
5453 nr_pages = page_counter_read(&memcg->memory);
5454 if (nr_pages > high)
5455 try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
5458 memcg_wb_domain_size_changed(memcg);
5462 static int memory_max_show(struct seq_file *m, void *v)
5464 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5465 unsigned long max = READ_ONCE(memcg->memory.max);
5467 if (max == PAGE_COUNTER_MAX)
5468 seq_puts(m, "max\n");
5470 seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
5475 static ssize_t memory_max_write(struct kernfs_open_file *of,
5476 char *buf, size_t nbytes, loff_t off)
5478 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5479 unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES;
5480 bool drained = false;
5484 buf = strstrip(buf);
5485 err = page_counter_memparse(buf, "max", &max);
5489 xchg(&memcg->memory.max, max);
5492 unsigned long nr_pages = page_counter_read(&memcg->memory);
5494 if (nr_pages <= max)
5497 if (signal_pending(current)) {
5503 drain_all_stock(memcg);
5509 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
5515 memcg_memory_event(memcg, MEMCG_OOM);
5516 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
5520 memcg_wb_domain_size_changed(memcg);
5524 static int memory_events_show(struct seq_file *m, void *v)
5526 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5528 seq_printf(m, "low %lu\n",
5529 atomic_long_read(&memcg->memory_events[MEMCG_LOW]));
5530 seq_printf(m, "high %lu\n",
5531 atomic_long_read(&memcg->memory_events[MEMCG_HIGH]));
5532 seq_printf(m, "max %lu\n",
5533 atomic_long_read(&memcg->memory_events[MEMCG_MAX]));
5534 seq_printf(m, "oom %lu\n",
5535 atomic_long_read(&memcg->memory_events[MEMCG_OOM]));
5536 seq_printf(m, "oom_kill %lu\n",
5537 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
5542 static int memory_stat_show(struct seq_file *m, void *v)
5544 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5545 struct accumulated_stats acc;
5549 * Provide statistics on the state of the memory subsystem as
5550 * well as cumulative event counters that show past behavior.
5552 * This list is ordered following a combination of these gradients:
5553 * 1) generic big picture -> specifics and details
5554 * 2) reflecting userspace activity -> reflecting kernel heuristics
5556 * Current memory state:
5559 memset(&acc, 0, sizeof(acc));
5560 acc.stats_size = MEMCG_NR_STAT;
5561 acc.events_size = NR_VM_EVENT_ITEMS;
5562 accumulate_memcg_tree(memcg, &acc);
5564 seq_printf(m, "anon %llu\n",
5565 (u64)acc.stat[MEMCG_RSS] * PAGE_SIZE);
5566 seq_printf(m, "file %llu\n",
5567 (u64)acc.stat[MEMCG_CACHE] * PAGE_SIZE);
5568 seq_printf(m, "kernel_stack %llu\n",
5569 (u64)acc.stat[MEMCG_KERNEL_STACK_KB] * 1024);
5570 seq_printf(m, "slab %llu\n",
5571 (u64)(acc.stat[NR_SLAB_RECLAIMABLE] +
5572 acc.stat[NR_SLAB_UNRECLAIMABLE]) * PAGE_SIZE);
5573 seq_printf(m, "sock %llu\n",
5574 (u64)acc.stat[MEMCG_SOCK] * PAGE_SIZE);
5576 seq_printf(m, "shmem %llu\n",
5577 (u64)acc.stat[NR_SHMEM] * PAGE_SIZE);
5578 seq_printf(m, "file_mapped %llu\n",
5579 (u64)acc.stat[NR_FILE_MAPPED] * PAGE_SIZE);
5580 seq_printf(m, "file_dirty %llu\n",
5581 (u64)acc.stat[NR_FILE_DIRTY] * PAGE_SIZE);
5582 seq_printf(m, "file_writeback %llu\n",
5583 (u64)acc.stat[NR_WRITEBACK] * PAGE_SIZE);
5585 for (i = 0; i < NR_LRU_LISTS; i++)
5586 seq_printf(m, "%s %llu\n", mem_cgroup_lru_names[i],
5587 (u64)acc.lru_pages[i] * PAGE_SIZE);
5589 seq_printf(m, "slab_reclaimable %llu\n",
5590 (u64)acc.stat[NR_SLAB_RECLAIMABLE] * PAGE_SIZE);
5591 seq_printf(m, "slab_unreclaimable %llu\n",
5592 (u64)acc.stat[NR_SLAB_UNRECLAIMABLE] * PAGE_SIZE);
5594 /* Accumulated memory events */
5596 seq_printf(m, "pgfault %lu\n", acc.events[PGFAULT]);
5597 seq_printf(m, "pgmajfault %lu\n", acc.events[PGMAJFAULT]);
5599 seq_printf(m, "workingset_refault %lu\n",
5600 acc.stat[WORKINGSET_REFAULT]);
5601 seq_printf(m, "workingset_activate %lu\n",
5602 acc.stat[WORKINGSET_ACTIVATE]);
5603 seq_printf(m, "workingset_nodereclaim %lu\n",
5604 acc.stat[WORKINGSET_NODERECLAIM]);
5606 seq_printf(m, "pgrefill %lu\n", acc.events[PGREFILL]);
5607 seq_printf(m, "pgscan %lu\n", acc.events[PGSCAN_KSWAPD] +
5608 acc.events[PGSCAN_DIRECT]);
5609 seq_printf(m, "pgsteal %lu\n", acc.events[PGSTEAL_KSWAPD] +
5610 acc.events[PGSTEAL_DIRECT]);
5611 seq_printf(m, "pgactivate %lu\n", acc.events[PGACTIVATE]);
5612 seq_printf(m, "pgdeactivate %lu\n", acc.events[PGDEACTIVATE]);
5613 seq_printf(m, "pglazyfree %lu\n", acc.events[PGLAZYFREE]);
5614 seq_printf(m, "pglazyfreed %lu\n", acc.events[PGLAZYFREED]);
5619 static int memory_oom_group_show(struct seq_file *m, void *v)
5621 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
5623 seq_printf(m, "%d\n", memcg->oom_group);
5628 static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
5629 char *buf, size_t nbytes, loff_t off)
5631 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5634 buf = strstrip(buf);
5638 ret = kstrtoint(buf, 0, &oom_group);
5642 if (oom_group != 0 && oom_group != 1)
5645 memcg->oom_group = oom_group;
5650 static struct cftype memory_files[] = {
5653 .flags = CFTYPE_NOT_ON_ROOT,
5654 .read_u64 = memory_current_read,
5658 .flags = CFTYPE_NOT_ON_ROOT,
5659 .seq_show = memory_min_show,
5660 .write = memory_min_write,
5664 .flags = CFTYPE_NOT_ON_ROOT,
5665 .seq_show = memory_low_show,
5666 .write = memory_low_write,
5670 .flags = CFTYPE_NOT_ON_ROOT,
5671 .seq_show = memory_high_show,
5672 .write = memory_high_write,
5676 .flags = CFTYPE_NOT_ON_ROOT,
5677 .seq_show = memory_max_show,
5678 .write = memory_max_write,
5682 .flags = CFTYPE_NOT_ON_ROOT,
5683 .file_offset = offsetof(struct mem_cgroup, events_file),
5684 .seq_show = memory_events_show,
5688 .flags = CFTYPE_NOT_ON_ROOT,
5689 .seq_show = memory_stat_show,
5692 .name = "oom.group",
5693 .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
5694 .seq_show = memory_oom_group_show,
5695 .write = memory_oom_group_write,
5700 struct cgroup_subsys memory_cgrp_subsys = {
5701 .css_alloc = mem_cgroup_css_alloc,
5702 .css_online = mem_cgroup_css_online,
5703 .css_offline = mem_cgroup_css_offline,
5704 .css_released = mem_cgroup_css_released,
5705 .css_free = mem_cgroup_css_free,
5706 .css_reset = mem_cgroup_css_reset,
5707 .can_attach = mem_cgroup_can_attach,
5708 .cancel_attach = mem_cgroup_cancel_attach,
5709 .post_attach = mem_cgroup_move_task,
5710 .bind = mem_cgroup_bind,
5711 .dfl_cftypes = memory_files,
5712 .legacy_cftypes = mem_cgroup_legacy_files,
5717 * mem_cgroup_protected - check if memory consumption is in the normal range
5718 * @root: the top ancestor of the sub-tree being checked
5719 * @memcg: the memory cgroup to check
5721 * WARNING: This function is not stateless! It can only be used as part
5722 * of a top-down tree iteration, not for isolated queries.
5724 * Returns one of the following:
5725 * MEMCG_PROT_NONE: cgroup memory is not protected
5726 * MEMCG_PROT_LOW: cgroup memory is protected as long there is
5727 * an unprotected supply of reclaimable memory from other cgroups.
5728 * MEMCG_PROT_MIN: cgroup memory is protected
5730 * @root is exclusive; it is never protected when looked at directly
5732 * To provide a proper hierarchical behavior, effective memory.min/low values
5733 * are used. Below is the description of how effective memory.low is calculated.
5734 * Effective memory.min values is calculated in the same way.
5736 * Effective memory.low is always equal or less than the original memory.low.
5737 * If there is no memory.low overcommittment (which is always true for
5738 * top-level memory cgroups), these two values are equal.
5739 * Otherwise, it's a part of parent's effective memory.low,
5740 * calculated as a cgroup's memory.low usage divided by sum of sibling's
5741 * memory.low usages, where memory.low usage is the size of actually
5745 * elow = min( memory.low, parent->elow * ------------------ ),
5746 * siblings_low_usage
5748 * | memory.current, if memory.current < memory.low
5753 * Such definition of the effective memory.low provides the expected
5754 * hierarchical behavior: parent's memory.low value is limiting
5755 * children, unprotected memory is reclaimed first and cgroups,
5756 * which are not using their guarantee do not affect actual memory
5759 * For example, if there are memcgs A, A/B, A/C, A/D and A/E:
5761 * A A/memory.low = 2G, A/memory.current = 6G
5763 * BC DE B/memory.low = 3G B/memory.current = 2G
5764 * C/memory.low = 1G C/memory.current = 2G
5765 * D/memory.low = 0 D/memory.current = 2G
5766 * E/memory.low = 10G E/memory.current = 0
5768 * and the memory pressure is applied, the following memory distribution
5769 * is expected (approximately):
5771 * A/memory.current = 2G
5773 * B/memory.current = 1.3G
5774 * C/memory.current = 0.6G
5775 * D/memory.current = 0
5776 * E/memory.current = 0
5778 * These calculations require constant tracking of the actual low usages
5779 * (see propagate_protected_usage()), as well as recursive calculation of
5780 * effective memory.low values. But as we do call mem_cgroup_protected()
5781 * path for each memory cgroup top-down from the reclaim,
5782 * it's possible to optimize this part, and save calculated elow
5783 * for next usage. This part is intentionally racy, but it's ok,
5784 * as memory.low is a best-effort mechanism.
5786 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
5787 struct mem_cgroup *memcg)
5789 struct mem_cgroup *parent;
5790 unsigned long emin, parent_emin;
5791 unsigned long elow, parent_elow;
5792 unsigned long usage;
5794 if (mem_cgroup_disabled())
5795 return MEMCG_PROT_NONE;
5798 root = root_mem_cgroup;
5800 return MEMCG_PROT_NONE;
5802 usage = page_counter_read(&memcg->memory);
5804 return MEMCG_PROT_NONE;
5806 emin = memcg->memory.min;
5807 elow = memcg->memory.low;
5809 parent = parent_mem_cgroup(memcg);
5810 /* No parent means a non-hierarchical mode on v1 memcg */
5812 return MEMCG_PROT_NONE;
5817 parent_emin = READ_ONCE(parent->memory.emin);
5818 emin = min(emin, parent_emin);
5819 if (emin && parent_emin) {
5820 unsigned long min_usage, siblings_min_usage;
5822 min_usage = min(usage, memcg->memory.min);
5823 siblings_min_usage = atomic_long_read(
5824 &parent->memory.children_min_usage);
5826 if (min_usage && siblings_min_usage)
5827 emin = min(emin, parent_emin * min_usage /
5828 siblings_min_usage);
5831 parent_elow = READ_ONCE(parent->memory.elow);
5832 elow = min(elow, parent_elow);
5833 if (elow && parent_elow) {
5834 unsigned long low_usage, siblings_low_usage;
5836 low_usage = min(usage, memcg->memory.low);
5837 siblings_low_usage = atomic_long_read(
5838 &parent->memory.children_low_usage);
5840 if (low_usage && siblings_low_usage)
5841 elow = min(elow, parent_elow * low_usage /
5842 siblings_low_usage);
5846 memcg->memory.emin = emin;
5847 memcg->memory.elow = elow;
5850 return MEMCG_PROT_MIN;
5851 else if (usage <= elow)
5852 return MEMCG_PROT_LOW;
5854 return MEMCG_PROT_NONE;
5858 * mem_cgroup_try_charge - try charging a page
5859 * @page: page to charge
5860 * @mm: mm context of the victim
5861 * @gfp_mask: reclaim mode
5862 * @memcgp: charged memcg return
5863 * @compound: charge the page as compound or small page
5865 * Try to charge @page to the memcg that @mm belongs to, reclaiming
5866 * pages according to @gfp_mask if necessary.
5868 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
5869 * Otherwise, an error code is returned.
5871 * After page->mapping has been set up, the caller must finalize the
5872 * charge with mem_cgroup_commit_charge(). Or abort the transaction
5873 * with mem_cgroup_cancel_charge() in case page instantiation fails.
5875 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
5876 gfp_t gfp_mask, struct mem_cgroup **memcgp,
5879 struct mem_cgroup *memcg = NULL;
5880 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5883 if (mem_cgroup_disabled())
5886 if (PageSwapCache(page)) {
5888 * Every swap fault against a single page tries to charge the
5889 * page, bail as early as possible. shmem_unuse() encounters
5890 * already charged pages, too. The USED bit is protected by
5891 * the page lock, which serializes swap cache removal, which
5892 * in turn serializes uncharging.
5894 VM_BUG_ON_PAGE(!PageLocked(page), page);
5895 if (compound_head(page)->mem_cgroup)
5898 if (do_swap_account) {
5899 swp_entry_t ent = { .val = page_private(page), };
5900 unsigned short id = lookup_swap_cgroup_id(ent);
5903 memcg = mem_cgroup_from_id(id);
5904 if (memcg && !css_tryget_online(&memcg->css))
5911 memcg = get_mem_cgroup_from_mm(mm);
5913 ret = try_charge(memcg, gfp_mask, nr_pages);
5915 css_put(&memcg->css);
5921 int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm,
5922 gfp_t gfp_mask, struct mem_cgroup **memcgp,
5925 struct mem_cgroup *memcg;
5928 ret = mem_cgroup_try_charge(page, mm, gfp_mask, memcgp, compound);
5930 mem_cgroup_throttle_swaprate(memcg, page_to_nid(page), gfp_mask);
5935 * mem_cgroup_commit_charge - commit a page charge
5936 * @page: page to charge
5937 * @memcg: memcg to charge the page to
5938 * @lrucare: page might be on LRU already
5939 * @compound: charge the page as compound or small page
5941 * Finalize a charge transaction started by mem_cgroup_try_charge(),
5942 * after page->mapping has been set up. This must happen atomically
5943 * as part of the page instantiation, i.e. under the page table lock
5944 * for anonymous pages, under the page lock for page and swap cache.
5946 * In addition, the page must not be on the LRU during the commit, to
5947 * prevent racing with task migration. If it might be, use @lrucare.
5949 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
5951 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
5952 bool lrucare, bool compound)
5954 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5956 VM_BUG_ON_PAGE(!page->mapping, page);
5957 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
5959 if (mem_cgroup_disabled())
5962 * Swap faults will attempt to charge the same page multiple
5963 * times. But reuse_swap_page() might have removed the page
5964 * from swapcache already, so we can't check PageSwapCache().
5969 commit_charge(page, memcg, lrucare);
5971 local_irq_disable();
5972 mem_cgroup_charge_statistics(memcg, page, compound, nr_pages);
5973 memcg_check_events(memcg, page);
5976 if (do_memsw_account() && PageSwapCache(page)) {
5977 swp_entry_t entry = { .val = page_private(page) };
5979 * The swap entry might not get freed for a long time,
5980 * let's not wait for it. The page already received a
5981 * memory+swap charge, drop the swap entry duplicate.
5983 mem_cgroup_uncharge_swap(entry, nr_pages);
5988 * mem_cgroup_cancel_charge - cancel a page charge
5989 * @page: page to charge
5990 * @memcg: memcg to charge the page to
5991 * @compound: charge the page as compound or small page
5993 * Cancel a charge transaction started by mem_cgroup_try_charge().
5995 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
5998 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
6000 if (mem_cgroup_disabled())
6003 * Swap faults will attempt to charge the same page multiple
6004 * times. But reuse_swap_page() might have removed the page
6005 * from swapcache already, so we can't check PageSwapCache().
6010 cancel_charge(memcg, nr_pages);
6013 struct uncharge_gather {
6014 struct mem_cgroup *memcg;
6015 unsigned long pgpgout;
6016 unsigned long nr_anon;
6017 unsigned long nr_file;
6018 unsigned long nr_kmem;
6019 unsigned long nr_huge;
6020 unsigned long nr_shmem;
6021 struct page *dummy_page;
6024 static inline void uncharge_gather_clear(struct uncharge_gather *ug)
6026 memset(ug, 0, sizeof(*ug));
6029 static void uncharge_batch(const struct uncharge_gather *ug)
6031 unsigned long nr_pages = ug->nr_anon + ug->nr_file + ug->nr_kmem;
6032 unsigned long flags;
6034 if (!mem_cgroup_is_root(ug->memcg)) {
6035 page_counter_uncharge(&ug->memcg->memory, nr_pages);
6036 if (do_memsw_account())
6037 page_counter_uncharge(&ug->memcg->memsw, nr_pages);
6038 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem)
6039 page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem);
6040 memcg_oom_recover(ug->memcg);
6043 local_irq_save(flags);
6044 __mod_memcg_state(ug->memcg, MEMCG_RSS, -ug->nr_anon);
6045 __mod_memcg_state(ug->memcg, MEMCG_CACHE, -ug->nr_file);
6046 __mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
6047 __mod_memcg_state(ug->memcg, NR_SHMEM, -ug->nr_shmem);
6048 __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
6049 __this_cpu_add(ug->memcg->stat_cpu->nr_page_events, nr_pages);
6050 memcg_check_events(ug->memcg, ug->dummy_page);
6051 local_irq_restore(flags);
6053 if (!mem_cgroup_is_root(ug->memcg))
6054 css_put_many(&ug->memcg->css, nr_pages);
6057 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
6059 VM_BUG_ON_PAGE(PageLRU(page), page);
6060 VM_BUG_ON_PAGE(page_count(page) && !is_zone_device_page(page) &&
6061 !PageHWPoison(page) , page);
6063 if (!page->mem_cgroup)
6067 * Nobody should be changing or seriously looking at
6068 * page->mem_cgroup at this point, we have fully
6069 * exclusive access to the page.
6072 if (ug->memcg != page->mem_cgroup) {
6075 uncharge_gather_clear(ug);
6077 ug->memcg = page->mem_cgroup;
6080 if (!PageKmemcg(page)) {
6081 unsigned int nr_pages = 1;
6083 if (PageTransHuge(page)) {
6084 nr_pages <<= compound_order(page);
6085 ug->nr_huge += nr_pages;
6088 ug->nr_anon += nr_pages;
6090 ug->nr_file += nr_pages;
6091 if (PageSwapBacked(page))
6092 ug->nr_shmem += nr_pages;
6096 ug->nr_kmem += 1 << compound_order(page);
6097 __ClearPageKmemcg(page);
6100 ug->dummy_page = page;
6101 page->mem_cgroup = NULL;
6104 static void uncharge_list(struct list_head *page_list)
6106 struct uncharge_gather ug;
6107 struct list_head *next;
6109 uncharge_gather_clear(&ug);
6112 * Note that the list can be a single page->lru; hence the
6113 * do-while loop instead of a simple list_for_each_entry().
6115 next = page_list->next;
6119 page = list_entry(next, struct page, lru);
6120 next = page->lru.next;
6122 uncharge_page(page, &ug);
6123 } while (next != page_list);
6126 uncharge_batch(&ug);
6130 * mem_cgroup_uncharge - uncharge a page
6131 * @page: page to uncharge
6133 * Uncharge a page previously charged with mem_cgroup_try_charge() and
6134 * mem_cgroup_commit_charge().
6136 void mem_cgroup_uncharge(struct page *page)
6138 struct uncharge_gather ug;
6140 if (mem_cgroup_disabled())
6143 /* Don't touch page->lru of any random page, pre-check: */
6144 if (!page->mem_cgroup)
6147 uncharge_gather_clear(&ug);
6148 uncharge_page(page, &ug);
6149 uncharge_batch(&ug);
6153 * mem_cgroup_uncharge_list - uncharge a list of page
6154 * @page_list: list of pages to uncharge
6156 * Uncharge a list of pages previously charged with
6157 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
6159 void mem_cgroup_uncharge_list(struct list_head *page_list)
6161 if (mem_cgroup_disabled())
6164 if (!list_empty(page_list))
6165 uncharge_list(page_list);
6169 * mem_cgroup_migrate - charge a page's replacement
6170 * @oldpage: currently circulating page
6171 * @newpage: replacement page
6173 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6174 * be uncharged upon free.
6176 * Both pages must be locked, @newpage->mapping must be set up.
6178 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
6180 struct mem_cgroup *memcg;
6181 unsigned int nr_pages;
6183 unsigned long flags;
6185 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
6186 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
6187 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
6188 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
6191 if (mem_cgroup_disabled())
6194 /* Page cache replacement: new page already charged? */
6195 if (newpage->mem_cgroup)
6198 /* Swapcache readahead pages can get replaced before being charged */
6199 memcg = oldpage->mem_cgroup;
6203 /* Force-charge the new page. The old one will be freed soon */
6204 compound = PageTransHuge(newpage);
6205 nr_pages = compound ? hpage_nr_pages(newpage) : 1;
6207 page_counter_charge(&memcg->memory, nr_pages);
6208 if (do_memsw_account())
6209 page_counter_charge(&memcg->memsw, nr_pages);
6210 css_get_many(&memcg->css, nr_pages);
6212 commit_charge(newpage, memcg, false);
6214 local_irq_save(flags);
6215 mem_cgroup_charge_statistics(memcg, newpage, compound, nr_pages);
6216 memcg_check_events(memcg, newpage);
6217 local_irq_restore(flags);
6220 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
6221 EXPORT_SYMBOL(memcg_sockets_enabled_key);
6223 void mem_cgroup_sk_alloc(struct sock *sk)
6225 struct mem_cgroup *memcg;
6227 if (!mem_cgroup_sockets_enabled)
6231 * Socket cloning can throw us here with sk_memcg already
6232 * filled. It won't however, necessarily happen from
6233 * process context. So the test for root memcg given
6234 * the current task's memcg won't help us in this case.
6236 * Respecting the original socket's memcg is a better
6237 * decision in this case.
6240 css_get(&sk->sk_memcg->css);
6245 memcg = mem_cgroup_from_task(current);
6246 if (memcg == root_mem_cgroup)
6248 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
6250 if (css_tryget_online(&memcg->css))
6251 sk->sk_memcg = memcg;
6256 void mem_cgroup_sk_free(struct sock *sk)
6259 css_put(&sk->sk_memcg->css);
6263 * mem_cgroup_charge_skmem - charge socket memory
6264 * @memcg: memcg to charge
6265 * @nr_pages: number of pages to charge
6267 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
6268 * @memcg's configured limit, %false if the charge had to be forced.
6270 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
6272 gfp_t gfp_mask = GFP_KERNEL;
6274 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
6275 struct page_counter *fail;
6277 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
6278 memcg->tcpmem_pressure = 0;
6281 page_counter_charge(&memcg->tcpmem, nr_pages);
6282 memcg->tcpmem_pressure = 1;
6286 /* Don't block in the packet receive path */
6288 gfp_mask = GFP_NOWAIT;
6290 mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
6292 if (try_charge(memcg, gfp_mask, nr_pages) == 0)
6295 try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages);
6300 * mem_cgroup_uncharge_skmem - uncharge socket memory
6301 * @memcg: memcg to uncharge
6302 * @nr_pages: number of pages to uncharge
6304 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
6306 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
6307 page_counter_uncharge(&memcg->tcpmem, nr_pages);
6311 mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
6313 refill_stock(memcg, nr_pages);
6316 static int __init cgroup_memory(char *s)
6320 while ((token = strsep(&s, ",")) != NULL) {
6323 if (!strcmp(token, "nosocket"))
6324 cgroup_memory_nosocket = true;
6325 if (!strcmp(token, "nokmem"))
6326 cgroup_memory_nokmem = true;
6330 __setup("cgroup.memory=", cgroup_memory);
6333 * subsys_initcall() for memory controller.
6335 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
6336 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
6337 * basically everything that doesn't depend on a specific mem_cgroup structure
6338 * should be initialized from here.
6340 static int __init mem_cgroup_init(void)
6344 #ifdef CONFIG_MEMCG_KMEM
6346 * Kmem cache creation is mostly done with the slab_mutex held,
6347 * so use a workqueue with limited concurrency to avoid stalling
6348 * all worker threads in case lots of cgroups are created and
6349 * destroyed simultaneously.
6351 memcg_kmem_cache_wq = alloc_workqueue("memcg_kmem_cache", 0, 1);
6352 BUG_ON(!memcg_kmem_cache_wq);
6355 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
6356 memcg_hotplug_cpu_dead);
6358 for_each_possible_cpu(cpu)
6359 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
6362 for_each_node(node) {
6363 struct mem_cgroup_tree_per_node *rtpn;
6365 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
6366 node_online(node) ? node : NUMA_NO_NODE);
6368 rtpn->rb_root = RB_ROOT;
6369 rtpn->rb_rightmost = NULL;
6370 spin_lock_init(&rtpn->lock);
6371 soft_limit_tree.rb_tree_per_node[node] = rtpn;
6376 subsys_initcall(mem_cgroup_init);
6378 #ifdef CONFIG_MEMCG_SWAP
6379 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
6381 while (!refcount_inc_not_zero(&memcg->id.ref)) {
6383 * The root cgroup cannot be destroyed, so it's refcount must
6386 if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
6390 memcg = parent_mem_cgroup(memcg);
6392 memcg = root_mem_cgroup;
6398 * mem_cgroup_swapout - transfer a memsw charge to swap
6399 * @page: page whose memsw charge to transfer
6400 * @entry: swap entry to move the charge to
6402 * Transfer the memsw charge of @page to @entry.
6404 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
6406 struct mem_cgroup *memcg, *swap_memcg;
6407 unsigned int nr_entries;
6408 unsigned short oldid;
6410 VM_BUG_ON_PAGE(PageLRU(page), page);
6411 VM_BUG_ON_PAGE(page_count(page), page);
6413 if (!do_memsw_account())
6416 memcg = page->mem_cgroup;
6418 /* Readahead page, never charged */
6423 * In case the memcg owning these pages has been offlined and doesn't
6424 * have an ID allocated to it anymore, charge the closest online
6425 * ancestor for the swap instead and transfer the memory+swap charge.
6427 swap_memcg = mem_cgroup_id_get_online(memcg);
6428 nr_entries = hpage_nr_pages(page);
6429 /* Get references for the tail pages, too */
6431 mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
6432 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
6434 VM_BUG_ON_PAGE(oldid, page);
6435 mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
6437 page->mem_cgroup = NULL;
6439 if (!mem_cgroup_is_root(memcg))
6440 page_counter_uncharge(&memcg->memory, nr_entries);
6442 if (memcg != swap_memcg) {
6443 if (!mem_cgroup_is_root(swap_memcg))
6444 page_counter_charge(&swap_memcg->memsw, nr_entries);
6445 page_counter_uncharge(&memcg->memsw, nr_entries);
6449 * Interrupts should be disabled here because the caller holds the
6450 * i_pages lock which is taken with interrupts-off. It is
6451 * important here to have the interrupts disabled because it is the
6452 * only synchronisation we have for updating the per-CPU variables.
6454 VM_BUG_ON(!irqs_disabled());
6455 mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
6457 memcg_check_events(memcg, page);
6459 if (!mem_cgroup_is_root(memcg))
6460 css_put_many(&memcg->css, nr_entries);
6464 * mem_cgroup_try_charge_swap - try charging swap space for a page
6465 * @page: page being added to swap
6466 * @entry: swap entry to charge
6468 * Try to charge @page's memcg for the swap space at @entry.
6470 * Returns 0 on success, -ENOMEM on failure.
6472 int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
6474 unsigned int nr_pages = hpage_nr_pages(page);
6475 struct page_counter *counter;
6476 struct mem_cgroup *memcg;
6477 unsigned short oldid;
6479 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !do_swap_account)
6482 memcg = page->mem_cgroup;
6484 /* Readahead page, never charged */
6489 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
6493 memcg = mem_cgroup_id_get_online(memcg);
6495 if (!mem_cgroup_is_root(memcg) &&
6496 !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
6497 memcg_memory_event(memcg, MEMCG_SWAP_MAX);
6498 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
6499 mem_cgroup_id_put(memcg);
6503 /* Get references for the tail pages, too */
6505 mem_cgroup_id_get_many(memcg, nr_pages - 1);
6506 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
6507 VM_BUG_ON_PAGE(oldid, page);
6508 mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
6514 * mem_cgroup_uncharge_swap - uncharge swap space
6515 * @entry: swap entry to uncharge
6516 * @nr_pages: the amount of swap space to uncharge
6518 void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
6520 struct mem_cgroup *memcg;
6523 if (!do_swap_account)
6526 id = swap_cgroup_record(entry, 0, nr_pages);
6528 memcg = mem_cgroup_from_id(id);
6530 if (!mem_cgroup_is_root(memcg)) {
6531 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
6532 page_counter_uncharge(&memcg->swap, nr_pages);
6534 page_counter_uncharge(&memcg->memsw, nr_pages);
6536 mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
6537 mem_cgroup_id_put_many(memcg, nr_pages);
6542 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
6544 long nr_swap_pages = get_nr_swap_pages();
6546 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
6547 return nr_swap_pages;
6548 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
6549 nr_swap_pages = min_t(long, nr_swap_pages,
6550 READ_ONCE(memcg->swap.max) -
6551 page_counter_read(&memcg->swap));
6552 return nr_swap_pages;
6555 bool mem_cgroup_swap_full(struct page *page)
6557 struct mem_cgroup *memcg;
6559 VM_BUG_ON_PAGE(!PageLocked(page), page);
6563 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
6566 memcg = page->mem_cgroup;
6570 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
6571 if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max)
6577 /* for remember boot option*/
6578 #ifdef CONFIG_MEMCG_SWAP_ENABLED
6579 static int really_do_swap_account __initdata = 1;
6581 static int really_do_swap_account __initdata;
6584 static int __init enable_swap_account(char *s)
6586 if (!strcmp(s, "1"))
6587 really_do_swap_account = 1;
6588 else if (!strcmp(s, "0"))
6589 really_do_swap_account = 0;
6592 __setup("swapaccount=", enable_swap_account);
6594 static u64 swap_current_read(struct cgroup_subsys_state *css,
6597 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
6599 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
6602 static int swap_max_show(struct seq_file *m, void *v)
6604 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
6605 unsigned long max = READ_ONCE(memcg->swap.max);
6607 if (max == PAGE_COUNTER_MAX)
6608 seq_puts(m, "max\n");
6610 seq_printf(m, "%llu\n", (u64)max * PAGE_SIZE);
6615 static ssize_t swap_max_write(struct kernfs_open_file *of,
6616 char *buf, size_t nbytes, loff_t off)
6618 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6622 buf = strstrip(buf);
6623 err = page_counter_memparse(buf, "max", &max);
6627 xchg(&memcg->swap.max, max);
6632 static int swap_events_show(struct seq_file *m, void *v)
6634 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
6636 seq_printf(m, "max %lu\n",
6637 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
6638 seq_printf(m, "fail %lu\n",
6639 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
6644 static struct cftype swap_files[] = {
6646 .name = "swap.current",
6647 .flags = CFTYPE_NOT_ON_ROOT,
6648 .read_u64 = swap_current_read,
6652 .flags = CFTYPE_NOT_ON_ROOT,
6653 .seq_show = swap_max_show,
6654 .write = swap_max_write,
6657 .name = "swap.events",
6658 .flags = CFTYPE_NOT_ON_ROOT,
6659 .file_offset = offsetof(struct mem_cgroup, swap_events_file),
6660 .seq_show = swap_events_show,
6665 static struct cftype memsw_cgroup_files[] = {
6667 .name = "memsw.usage_in_bytes",
6668 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
6669 .read_u64 = mem_cgroup_read_u64,
6672 .name = "memsw.max_usage_in_bytes",
6673 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
6674 .write = mem_cgroup_reset,
6675 .read_u64 = mem_cgroup_read_u64,
6678 .name = "memsw.limit_in_bytes",
6679 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
6680 .write = mem_cgroup_write,
6681 .read_u64 = mem_cgroup_read_u64,
6684 .name = "memsw.failcnt",
6685 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
6686 .write = mem_cgroup_reset,
6687 .read_u64 = mem_cgroup_read_u64,
6689 { }, /* terminate */
6692 static int __init mem_cgroup_swap_init(void)
6694 if (!mem_cgroup_disabled() && really_do_swap_account) {
6695 do_swap_account = 1;
6696 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
6698 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
6699 memsw_cgroup_files));
6703 subsys_initcall(mem_cgroup_swap_init);
6705 #endif /* CONFIG_MEMCG_SWAP */