1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* memcontrol.c - Memory Controller
4 * Copyright IBM Corporation, 2007
5 * Author Balbir Singh <balbir@linux.vnet.ibm.com>
7 * Copyright 2007 OpenVZ SWsoft Inc
8 * Author: Pavel Emelianov <xemul@openvz.org>
11 * Copyright (C) 2009 Nokia Corporation
12 * Author: Kirill A. Shutemov
14 * Kernel Memory Controller
15 * Copyright (C) 2012 Parallels Inc. and Google Inc.
16 * Authors: Glauber Costa and Suleiman Souhlal
19 * Charge lifetime sanitation
20 * Lockless page tracking & accounting
21 * Unified hierarchy configuration model
22 * Copyright (C) 2015 Red Hat, Inc., Johannes Weiner
25 #include <linux/page_counter.h>
26 #include <linux/memcontrol.h>
27 #include <linux/cgroup.h>
28 #include <linux/pagewalk.h>
29 #include <linux/sched/mm.h>
30 #include <linux/shmem_fs.h>
31 #include <linux/hugetlb.h>
32 #include <linux/pagemap.h>
33 #include <linux/vm_event_item.h>
34 #include <linux/smp.h>
35 #include <linux/page-flags.h>
36 #include <linux/backing-dev.h>
37 #include <linux/bit_spinlock.h>
38 #include <linux/rcupdate.h>
39 #include <linux/limits.h>
40 #include <linux/export.h>
41 #include <linux/mutex.h>
42 #include <linux/rbtree.h>
43 #include <linux/slab.h>
44 #include <linux/swap.h>
45 #include <linux/swapops.h>
46 #include <linux/spinlock.h>
47 #include <linux/eventfd.h>
48 #include <linux/poll.h>
49 #include <linux/sort.h>
51 #include <linux/seq_file.h>
52 #include <linux/vmpressure.h>
53 #include <linux/mm_inline.h>
54 #include <linux/swap_cgroup.h>
55 #include <linux/cpu.h>
56 #include <linux/oom.h>
57 #include <linux/lockdep.h>
58 #include <linux/file.h>
59 #include <linux/tracehook.h>
60 #include <linux/psi.h>
61 #include <linux/seq_buf.h>
67 #include <linux/uaccess.h>
69 #include <trace/events/vmscan.h>
71 struct cgroup_subsys memory_cgrp_subsys __read_mostly;
72 EXPORT_SYMBOL(memory_cgrp_subsys);
74 struct mem_cgroup *root_mem_cgroup __read_mostly;
76 #define MEM_CGROUP_RECLAIM_RETRIES 5
78 /* Socket memory accounting disabled? */
79 static bool cgroup_memory_nosocket;
81 /* Kernel memory accounting disabled? */
82 static bool cgroup_memory_nokmem;
84 /* Whether the swap controller is active */
85 #ifdef CONFIG_MEMCG_SWAP
86 int do_swap_account __read_mostly;
88 #define do_swap_account 0
91 #ifdef CONFIG_CGROUP_WRITEBACK
92 static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
95 /* Whether legacy memory+swap accounting is active */
96 static bool do_memsw_account(void)
98 return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;
101 #define THRESHOLDS_EVENTS_TARGET 128
102 #define SOFTLIMIT_EVENTS_TARGET 1024
105 * Cgroups above their limits are maintained in a RB-Tree, independent of
106 * their hierarchy representation
109 struct mem_cgroup_tree_per_node {
110 struct rb_root rb_root;
111 struct rb_node *rb_rightmost;
115 struct mem_cgroup_tree {
116 struct mem_cgroup_tree_per_node *rb_tree_per_node[MAX_NUMNODES];
119 static struct mem_cgroup_tree soft_limit_tree __read_mostly;
122 struct mem_cgroup_eventfd_list {
123 struct list_head list;
124 struct eventfd_ctx *eventfd;
128 * cgroup_event represents events which userspace want to receive.
130 struct mem_cgroup_event {
132 * memcg which the event belongs to.
134 struct mem_cgroup *memcg;
136 * eventfd to signal userspace about the event.
138 struct eventfd_ctx *eventfd;
140 * Each of these stored in a list by the cgroup.
142 struct list_head list;
144 * register_event() callback will be used to add new userspace
145 * waiter for changes related to this event. Use eventfd_signal()
146 * on eventfd to send notification to userspace.
148 int (*register_event)(struct mem_cgroup *memcg,
149 struct eventfd_ctx *eventfd, const char *args);
151 * unregister_event() callback will be called when userspace closes
152 * the eventfd or on cgroup removing. This callback must be set,
153 * if you want provide notification functionality.
155 void (*unregister_event)(struct mem_cgroup *memcg,
156 struct eventfd_ctx *eventfd);
158 * All fields below needed to unregister event when
159 * userspace closes eventfd.
162 wait_queue_head_t *wqh;
163 wait_queue_entry_t wait;
164 struct work_struct remove;
167 static void mem_cgroup_threshold(struct mem_cgroup *memcg);
168 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
170 /* Stuffs for move charges at task migration. */
172 * Types of charges to be moved.
174 #define MOVE_ANON 0x1U
175 #define MOVE_FILE 0x2U
176 #define MOVE_MASK (MOVE_ANON | MOVE_FILE)
178 /* "mc" and its members are protected by cgroup_mutex */
179 static struct move_charge_struct {
180 spinlock_t lock; /* for from, to */
181 struct mm_struct *mm;
182 struct mem_cgroup *from;
183 struct mem_cgroup *to;
185 unsigned long precharge;
186 unsigned long moved_charge;
187 unsigned long moved_swap;
188 struct task_struct *moving_task; /* a task moving charges */
189 wait_queue_head_t waitq; /* a waitq for other context */
191 .lock = __SPIN_LOCK_UNLOCKED(mc.lock),
192 .waitq = __WAIT_QUEUE_HEAD_INITIALIZER(mc.waitq),
196 * Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
197 * limit reclaim to prevent infinite loops, if they ever occur.
199 #define MEM_CGROUP_MAX_RECLAIM_LOOPS 100
200 #define MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS 2
203 MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
204 MEM_CGROUP_CHARGE_TYPE_ANON,
205 MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
206 MEM_CGROUP_CHARGE_TYPE_DROP, /* a page was unused swap cache */
210 /* for encoding cft->private value on file */
219 #define MEMFILE_PRIVATE(x, val) ((x) << 16 | (val))
220 #define MEMFILE_TYPE(val) ((val) >> 16 & 0xffff)
221 #define MEMFILE_ATTR(val) ((val) & 0xffff)
222 /* Used for OOM nofiier */
223 #define OOM_CONTROL (0)
226 * Iteration constructs for visiting all cgroups (under a tree). If
227 * loops are exited prematurely (break), mem_cgroup_iter_break() must
228 * be used for reference counting.
230 #define for_each_mem_cgroup_tree(iter, root) \
231 for (iter = mem_cgroup_iter(root, NULL, NULL); \
233 iter = mem_cgroup_iter(root, iter, NULL))
235 #define for_each_mem_cgroup(iter) \
236 for (iter = mem_cgroup_iter(NULL, NULL, NULL); \
238 iter = mem_cgroup_iter(NULL, iter, NULL))
240 static inline bool should_force_charge(void)
242 return tsk_is_oom_victim(current) || fatal_signal_pending(current) ||
243 (current->flags & PF_EXITING);
246 /* Some nice accessors for the vmpressure. */
247 struct vmpressure *memcg_to_vmpressure(struct mem_cgroup *memcg)
250 memcg = root_mem_cgroup;
251 return &memcg->vmpressure;
254 struct cgroup_subsys_state *vmpressure_to_css(struct vmpressure *vmpr)
256 return &container_of(vmpr, struct mem_cgroup, vmpressure)->css;
259 #ifdef CONFIG_MEMCG_KMEM
261 * This will be the memcg's index in each cache's ->memcg_params.memcg_caches.
262 * The main reason for not using cgroup id for this:
263 * this works better in sparse environments, where we have a lot of memcgs,
264 * but only a few kmem-limited. Or also, if we have, for instance, 200
265 * memcgs, and none but the 200th is kmem-limited, we'd have to have a
266 * 200 entry array for that.
268 * The current size of the caches array is stored in memcg_nr_cache_ids. It
269 * will double each time we have to increase it.
271 static DEFINE_IDA(memcg_cache_ida);
272 int memcg_nr_cache_ids;
274 /* Protects memcg_nr_cache_ids */
275 static DECLARE_RWSEM(memcg_cache_ids_sem);
277 void memcg_get_cache_ids(void)
279 down_read(&memcg_cache_ids_sem);
282 void memcg_put_cache_ids(void)
284 up_read(&memcg_cache_ids_sem);
288 * MIN_SIZE is different than 1, because we would like to avoid going through
289 * the alloc/free process all the time. In a small machine, 4 kmem-limited
290 * cgroups is a reasonable guess. In the future, it could be a parameter or
291 * tunable, but that is strictly not necessary.
293 * MAX_SIZE should be as large as the number of cgrp_ids. Ideally, we could get
294 * this constant directly from cgroup, but it is understandable that this is
295 * better kept as an internal representation in cgroup.c. In any case, the
296 * cgrp_id space is not getting any smaller, and we don't have to necessarily
297 * increase ours as well if it increases.
299 #define MEMCG_CACHES_MIN_SIZE 4
300 #define MEMCG_CACHES_MAX_SIZE MEM_CGROUP_ID_MAX
303 * A lot of the calls to the cache allocation functions are expected to be
304 * inlined by the compiler. Since the calls to memcg_kmem_get_cache are
305 * conditional to this static branch, we'll have to allow modules that does
306 * kmem_cache_alloc and the such to see this symbol as well
308 DEFINE_STATIC_KEY_FALSE(memcg_kmem_enabled_key);
309 EXPORT_SYMBOL(memcg_kmem_enabled_key);
311 struct workqueue_struct *memcg_kmem_cache_wq;
314 static int memcg_shrinker_map_size;
315 static DEFINE_MUTEX(memcg_shrinker_map_mutex);
317 static void memcg_free_shrinker_map_rcu(struct rcu_head *head)
319 kvfree(container_of(head, struct memcg_shrinker_map, rcu));
322 static int memcg_expand_one_shrinker_map(struct mem_cgroup *memcg,
323 int size, int old_size)
325 struct memcg_shrinker_map *new, *old;
328 lockdep_assert_held(&memcg_shrinker_map_mutex);
331 old = rcu_dereference_protected(
332 mem_cgroup_nodeinfo(memcg, nid)->shrinker_map, true);
333 /* Not yet online memcg */
337 new = kvmalloc_node(sizeof(*new) + size, GFP_KERNEL, nid);
341 /* Set all old bits, clear all new bits */
342 memset(new->map, (int)0xff, old_size);
343 memset((void *)new->map + old_size, 0, size - old_size);
345 rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, new);
346 call_rcu(&old->rcu, memcg_free_shrinker_map_rcu);
352 static void memcg_free_shrinker_maps(struct mem_cgroup *memcg)
354 struct mem_cgroup_per_node *pn;
355 struct memcg_shrinker_map *map;
358 if (mem_cgroup_is_root(memcg))
362 pn = mem_cgroup_nodeinfo(memcg, nid);
363 map = rcu_dereference_protected(pn->shrinker_map, true);
366 rcu_assign_pointer(pn->shrinker_map, NULL);
370 static int memcg_alloc_shrinker_maps(struct mem_cgroup *memcg)
372 struct memcg_shrinker_map *map;
373 int nid, size, ret = 0;
375 if (mem_cgroup_is_root(memcg))
378 mutex_lock(&memcg_shrinker_map_mutex);
379 size = memcg_shrinker_map_size;
381 map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid);
383 memcg_free_shrinker_maps(memcg);
387 rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_map, map);
389 mutex_unlock(&memcg_shrinker_map_mutex);
394 int memcg_expand_shrinker_maps(int new_id)
396 int size, old_size, ret = 0;
397 struct mem_cgroup *memcg;
399 size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
400 old_size = memcg_shrinker_map_size;
401 if (size <= old_size)
404 mutex_lock(&memcg_shrinker_map_mutex);
405 if (!root_mem_cgroup)
408 for_each_mem_cgroup(memcg) {
409 if (mem_cgroup_is_root(memcg))
411 ret = memcg_expand_one_shrinker_map(memcg, size, old_size);
413 mem_cgroup_iter_break(NULL, memcg);
419 memcg_shrinker_map_size = size;
420 mutex_unlock(&memcg_shrinker_map_mutex);
424 void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
426 if (shrinker_id >= 0 && memcg && !mem_cgroup_is_root(memcg)) {
427 struct memcg_shrinker_map *map;
430 map = rcu_dereference(memcg->nodeinfo[nid]->shrinker_map);
431 /* Pairs with smp mb in shrink_slab() */
432 smp_mb__before_atomic();
433 set_bit(shrinker_id, map->map);
439 * mem_cgroup_css_from_page - css of the memcg associated with a page
440 * @page: page of interest
442 * If memcg is bound to the default hierarchy, css of the memcg associated
443 * with @page is returned. The returned css remains associated with @page
444 * until it is released.
446 * If memcg is bound to a traditional hierarchy, the css of root_mem_cgroup
449 struct cgroup_subsys_state *mem_cgroup_css_from_page(struct page *page)
451 struct mem_cgroup *memcg;
453 memcg = page->mem_cgroup;
455 if (!memcg || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
456 memcg = root_mem_cgroup;
462 * page_cgroup_ino - return inode number of the memcg a page is charged to
465 * Look up the closest online ancestor of the memory cgroup @page is charged to
466 * and return its inode number or 0 if @page is not charged to any cgroup. It
467 * is safe to call this function without holding a reference to @page.
469 * Note, this function is inherently racy, because there is nothing to prevent
470 * the cgroup inode from getting torn down and potentially reallocated a moment
471 * after page_cgroup_ino() returns, so it only should be used by callers that
472 * do not care (such as procfs interfaces).
474 ino_t page_cgroup_ino(struct page *page)
476 struct mem_cgroup *memcg;
477 unsigned long ino = 0;
480 if (PageSlab(page) && !PageTail(page))
481 memcg = memcg_from_slab_page(page);
483 memcg = READ_ONCE(page->mem_cgroup);
484 while (memcg && !(memcg->css.flags & CSS_ONLINE))
485 memcg = parent_mem_cgroup(memcg);
487 ino = cgroup_ino(memcg->css.cgroup);
492 static struct mem_cgroup_per_node *
493 mem_cgroup_page_nodeinfo(struct mem_cgroup *memcg, struct page *page)
495 int nid = page_to_nid(page);
497 return memcg->nodeinfo[nid];
500 static struct mem_cgroup_tree_per_node *
501 soft_limit_tree_node(int nid)
503 return soft_limit_tree.rb_tree_per_node[nid];
506 static struct mem_cgroup_tree_per_node *
507 soft_limit_tree_from_page(struct page *page)
509 int nid = page_to_nid(page);
511 return soft_limit_tree.rb_tree_per_node[nid];
514 static void __mem_cgroup_insert_exceeded(struct mem_cgroup_per_node *mz,
515 struct mem_cgroup_tree_per_node *mctz,
516 unsigned long new_usage_in_excess)
518 struct rb_node **p = &mctz->rb_root.rb_node;
519 struct rb_node *parent = NULL;
520 struct mem_cgroup_per_node *mz_node;
521 bool rightmost = true;
526 mz->usage_in_excess = new_usage_in_excess;
527 if (!mz->usage_in_excess)
531 mz_node = rb_entry(parent, struct mem_cgroup_per_node,
533 if (mz->usage_in_excess < mz_node->usage_in_excess) {
539 * We can't avoid mem cgroups that are over their soft
540 * limit by the same amount
542 else if (mz->usage_in_excess >= mz_node->usage_in_excess)
547 mctz->rb_rightmost = &mz->tree_node;
549 rb_link_node(&mz->tree_node, parent, p);
550 rb_insert_color(&mz->tree_node, &mctz->rb_root);
554 static void __mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
555 struct mem_cgroup_tree_per_node *mctz)
560 if (&mz->tree_node == mctz->rb_rightmost)
561 mctz->rb_rightmost = rb_prev(&mz->tree_node);
563 rb_erase(&mz->tree_node, &mctz->rb_root);
567 static void mem_cgroup_remove_exceeded(struct mem_cgroup_per_node *mz,
568 struct mem_cgroup_tree_per_node *mctz)
572 spin_lock_irqsave(&mctz->lock, flags);
573 __mem_cgroup_remove_exceeded(mz, mctz);
574 spin_unlock_irqrestore(&mctz->lock, flags);
577 static unsigned long soft_limit_excess(struct mem_cgroup *memcg)
579 unsigned long nr_pages = page_counter_read(&memcg->memory);
580 unsigned long soft_limit = READ_ONCE(memcg->soft_limit);
581 unsigned long excess = 0;
583 if (nr_pages > soft_limit)
584 excess = nr_pages - soft_limit;
589 static void mem_cgroup_update_tree(struct mem_cgroup *memcg, struct page *page)
591 unsigned long excess;
592 struct mem_cgroup_per_node *mz;
593 struct mem_cgroup_tree_per_node *mctz;
595 mctz = soft_limit_tree_from_page(page);
599 * Necessary to update all ancestors when hierarchy is used.
600 * because their event counter is not touched.
602 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
603 mz = mem_cgroup_page_nodeinfo(memcg, page);
604 excess = soft_limit_excess(memcg);
606 * We have to update the tree if mz is on RB-tree or
607 * mem is over its softlimit.
609 if (excess || mz->on_tree) {
612 spin_lock_irqsave(&mctz->lock, flags);
613 /* if on-tree, remove it */
615 __mem_cgroup_remove_exceeded(mz, mctz);
617 * Insert again. mz->usage_in_excess will be updated.
618 * If excess is 0, no tree ops.
620 __mem_cgroup_insert_exceeded(mz, mctz, excess);
621 spin_unlock_irqrestore(&mctz->lock, flags);
626 static void mem_cgroup_remove_from_trees(struct mem_cgroup *memcg)
628 struct mem_cgroup_tree_per_node *mctz;
629 struct mem_cgroup_per_node *mz;
633 mz = mem_cgroup_nodeinfo(memcg, nid);
634 mctz = soft_limit_tree_node(nid);
636 mem_cgroup_remove_exceeded(mz, mctz);
640 static struct mem_cgroup_per_node *
641 __mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
643 struct mem_cgroup_per_node *mz;
647 if (!mctz->rb_rightmost)
648 goto done; /* Nothing to reclaim from */
650 mz = rb_entry(mctz->rb_rightmost,
651 struct mem_cgroup_per_node, tree_node);
653 * Remove the node now but someone else can add it back,
654 * we will to add it back at the end of reclaim to its correct
655 * position in the tree.
657 __mem_cgroup_remove_exceeded(mz, mctz);
658 if (!soft_limit_excess(mz->memcg) ||
659 !css_tryget(&mz->memcg->css))
665 static struct mem_cgroup_per_node *
666 mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
668 struct mem_cgroup_per_node *mz;
670 spin_lock_irq(&mctz->lock);
671 mz = __mem_cgroup_largest_soft_limit_node(mctz);
672 spin_unlock_irq(&mctz->lock);
677 * __mod_memcg_state - update cgroup memory statistics
678 * @memcg: the memory cgroup
679 * @idx: the stat item - can be enum memcg_stat_item or enum node_stat_item
680 * @val: delta to add to the counter, can be negative
682 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
686 if (mem_cgroup_disabled())
689 x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]);
690 if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
691 struct mem_cgroup *mi;
694 * Batch local counters to keep them in sync with
695 * the hierarchical ones.
697 __this_cpu_add(memcg->vmstats_local->stat[idx], x);
698 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
699 atomic_long_add(x, &mi->vmstats[idx]);
702 __this_cpu_write(memcg->vmstats_percpu->stat[idx], x);
705 static struct mem_cgroup_per_node *
706 parent_nodeinfo(struct mem_cgroup_per_node *pn, int nid)
708 struct mem_cgroup *parent;
710 parent = parent_mem_cgroup(pn->memcg);
713 return mem_cgroup_nodeinfo(parent, nid);
717 * __mod_lruvec_state - update lruvec memory statistics
718 * @lruvec: the lruvec
719 * @idx: the stat item
720 * @val: delta to add to the counter, can be negative
722 * The lruvec is the intersection of the NUMA node and a cgroup. This
723 * function updates the all three counters that are affected by a
724 * change of state at this level: per-node, per-cgroup, per-lruvec.
726 void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
729 pg_data_t *pgdat = lruvec_pgdat(lruvec);
730 struct mem_cgroup_per_node *pn;
731 struct mem_cgroup *memcg;
735 __mod_node_page_state(pgdat, idx, val);
737 if (mem_cgroup_disabled())
740 pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
744 __mod_memcg_state(memcg, idx, val);
747 __this_cpu_add(pn->lruvec_stat_local->count[idx], val);
749 x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
750 if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
751 struct mem_cgroup_per_node *pi;
753 for (pi = pn; pi; pi = parent_nodeinfo(pi, pgdat->node_id))
754 atomic_long_add(x, &pi->lruvec_stat[idx]);
757 __this_cpu_write(pn->lruvec_stat_cpu->count[idx], x);
760 void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val)
762 pg_data_t *pgdat = page_pgdat(virt_to_page(p));
763 struct mem_cgroup *memcg;
764 struct lruvec *lruvec;
767 memcg = mem_cgroup_from_obj(p);
769 /* Untracked pages have no memcg, no lruvec. Update only the node */
770 if (!memcg || memcg == root_mem_cgroup) {
771 __mod_node_page_state(pgdat, idx, val);
773 lruvec = mem_cgroup_lruvec(memcg, pgdat);
774 __mod_lruvec_state(lruvec, idx, val);
779 void mod_memcg_obj_state(void *p, int idx, int val)
781 struct mem_cgroup *memcg;
784 memcg = mem_cgroup_from_obj(p);
786 mod_memcg_state(memcg, idx, val);
791 * __count_memcg_events - account VM events in a cgroup
792 * @memcg: the memory cgroup
793 * @idx: the event item
794 * @count: the number of events that occured
796 void __count_memcg_events(struct mem_cgroup *memcg, enum vm_event_item idx,
801 if (mem_cgroup_disabled())
804 x = count + __this_cpu_read(memcg->vmstats_percpu->events[idx]);
805 if (unlikely(x > MEMCG_CHARGE_BATCH)) {
806 struct mem_cgroup *mi;
809 * Batch local counters to keep them in sync with
810 * the hierarchical ones.
812 __this_cpu_add(memcg->vmstats_local->events[idx], x);
813 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
814 atomic_long_add(x, &mi->vmevents[idx]);
817 __this_cpu_write(memcg->vmstats_percpu->events[idx], x);
820 static unsigned long memcg_events(struct mem_cgroup *memcg, int event)
822 return atomic_long_read(&memcg->vmevents[event]);
825 static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
830 for_each_possible_cpu(cpu)
831 x += per_cpu(memcg->vmstats_local->events[event], cpu);
835 static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,
837 bool compound, int nr_pages)
840 * Here, RSS means 'mapped anon' and anon's SwapCache. Shmem/tmpfs is
841 * counted as CACHE even if it's on ANON LRU.
844 __mod_memcg_state(memcg, MEMCG_RSS, nr_pages);
846 __mod_memcg_state(memcg, MEMCG_CACHE, nr_pages);
847 if (PageSwapBacked(page))
848 __mod_memcg_state(memcg, NR_SHMEM, nr_pages);
852 VM_BUG_ON_PAGE(!PageTransHuge(page), page);
853 __mod_memcg_state(memcg, MEMCG_RSS_HUGE, nr_pages);
856 /* pagein of a big page is an event. So, ignore page size */
858 __count_memcg_events(memcg, PGPGIN, 1);
860 __count_memcg_events(memcg, PGPGOUT, 1);
861 nr_pages = -nr_pages; /* for event */
864 __this_cpu_add(memcg->vmstats_percpu->nr_page_events, nr_pages);
867 static bool mem_cgroup_event_ratelimit(struct mem_cgroup *memcg,
868 enum mem_cgroup_events_target target)
870 unsigned long val, next;
872 val = __this_cpu_read(memcg->vmstats_percpu->nr_page_events);
873 next = __this_cpu_read(memcg->vmstats_percpu->targets[target]);
874 /* from time_after() in jiffies.h */
875 if ((long)(next - val) < 0) {
877 case MEM_CGROUP_TARGET_THRESH:
878 next = val + THRESHOLDS_EVENTS_TARGET;
880 case MEM_CGROUP_TARGET_SOFTLIMIT:
881 next = val + SOFTLIMIT_EVENTS_TARGET;
886 __this_cpu_write(memcg->vmstats_percpu->targets[target], next);
893 * Check events in order.
896 static void memcg_check_events(struct mem_cgroup *memcg, struct page *page)
898 /* threshold event is triggered in finer grain than soft limit */
899 if (unlikely(mem_cgroup_event_ratelimit(memcg,
900 MEM_CGROUP_TARGET_THRESH))) {
903 do_softlimit = mem_cgroup_event_ratelimit(memcg,
904 MEM_CGROUP_TARGET_SOFTLIMIT);
905 mem_cgroup_threshold(memcg);
906 if (unlikely(do_softlimit))
907 mem_cgroup_update_tree(memcg, page);
911 struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
914 * mm_update_next_owner() may clear mm->owner to NULL
915 * if it races with swapoff, page migration, etc.
916 * So this can be called with p == NULL.
921 return mem_cgroup_from_css(task_css(p, memory_cgrp_id));
923 EXPORT_SYMBOL(mem_cgroup_from_task);
926 * get_mem_cgroup_from_mm: Obtain a reference on given mm_struct's memcg.
927 * @mm: mm from which memcg should be extracted. It can be NULL.
929 * Obtain a reference on mm->memcg and returns it if successful. Otherwise
930 * root_mem_cgroup is returned. However if mem_cgroup is disabled, NULL is
933 struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm)
935 struct mem_cgroup *memcg;
937 if (mem_cgroup_disabled())
943 * Page cache insertions can happen withou an
944 * actual mm context, e.g. during disk probing
945 * on boot, loopback IO, acct() writes etc.
948 memcg = root_mem_cgroup;
950 memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
951 if (unlikely(!memcg))
952 memcg = root_mem_cgroup;
954 } while (!css_tryget(&memcg->css));
958 EXPORT_SYMBOL(get_mem_cgroup_from_mm);
961 * get_mem_cgroup_from_page: Obtain a reference on given page's memcg.
962 * @page: page from which memcg should be extracted.
964 * Obtain a reference on page->memcg and returns it if successful. Otherwise
965 * root_mem_cgroup is returned.
967 struct mem_cgroup *get_mem_cgroup_from_page(struct page *page)
969 struct mem_cgroup *memcg = page->mem_cgroup;
971 if (mem_cgroup_disabled())
975 /* Page should not get uncharged and freed memcg under us. */
976 if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css)))
977 memcg = root_mem_cgroup;
981 EXPORT_SYMBOL(get_mem_cgroup_from_page);
984 * If current->active_memcg is non-NULL, do not fallback to current->mm->memcg.
986 static __always_inline struct mem_cgroup *get_mem_cgroup_from_current(void)
988 if (unlikely(current->active_memcg)) {
989 struct mem_cgroup *memcg;
992 /* current->active_memcg must hold a ref. */
993 if (WARN_ON_ONCE(!css_tryget(¤t->active_memcg->css)))
994 memcg = root_mem_cgroup;
996 memcg = current->active_memcg;
1000 return get_mem_cgroup_from_mm(current->mm);
1004 * mem_cgroup_iter - iterate over memory cgroup hierarchy
1005 * @root: hierarchy root
1006 * @prev: previously returned memcg, NULL on first invocation
1007 * @reclaim: cookie for shared reclaim walks, NULL for full walks
1009 * Returns references to children of the hierarchy below @root, or
1010 * @root itself, or %NULL after a full round-trip.
1012 * Caller must pass the return value in @prev on subsequent
1013 * invocations for reference counting, or use mem_cgroup_iter_break()
1014 * to cancel a hierarchy walk before the round-trip is complete.
1016 * Reclaimers can specify a node and a priority level in @reclaim to
1017 * divide up the memcgs in the hierarchy among all concurrent
1018 * reclaimers operating on the same node and priority.
1020 struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
1021 struct mem_cgroup *prev,
1022 struct mem_cgroup_reclaim_cookie *reclaim)
1024 struct mem_cgroup_reclaim_iter *uninitialized_var(iter);
1025 struct cgroup_subsys_state *css = NULL;
1026 struct mem_cgroup *memcg = NULL;
1027 struct mem_cgroup *pos = NULL;
1029 if (mem_cgroup_disabled())
1033 root = root_mem_cgroup;
1035 if (prev && !reclaim)
1038 if (!root->use_hierarchy && root != root_mem_cgroup) {
1047 struct mem_cgroup_per_node *mz;
1049 mz = mem_cgroup_nodeinfo(root, reclaim->pgdat->node_id);
1052 if (prev && reclaim->generation != iter->generation)
1056 pos = READ_ONCE(iter->position);
1057 if (!pos || css_tryget(&pos->css))
1060 * css reference reached zero, so iter->position will
1061 * be cleared by ->css_released. However, we should not
1062 * rely on this happening soon, because ->css_released
1063 * is called from a work queue, and by busy-waiting we
1064 * might block it. So we clear iter->position right
1067 (void)cmpxchg(&iter->position, pos, NULL);
1075 css = css_next_descendant_pre(css, &root->css);
1078 * Reclaimers share the hierarchy walk, and a
1079 * new one might jump in right at the end of
1080 * the hierarchy - make sure they see at least
1081 * one group and restart from the beginning.
1089 * Verify the css and acquire a reference. The root
1090 * is provided by the caller, so we know it's alive
1091 * and kicking, and don't take an extra reference.
1093 memcg = mem_cgroup_from_css(css);
1095 if (css == &root->css)
1098 if (css_tryget(css))
1106 * The position could have already been updated by a competing
1107 * thread, so check that the value hasn't changed since we read
1108 * it to avoid reclaiming from the same cgroup twice.
1110 (void)cmpxchg(&iter->position, pos, memcg);
1118 reclaim->generation = iter->generation;
1124 if (prev && prev != root)
1125 css_put(&prev->css);
1131 * mem_cgroup_iter_break - abort a hierarchy walk prematurely
1132 * @root: hierarchy root
1133 * @prev: last visited hierarchy member as returned by mem_cgroup_iter()
1135 void mem_cgroup_iter_break(struct mem_cgroup *root,
1136 struct mem_cgroup *prev)
1139 root = root_mem_cgroup;
1140 if (prev && prev != root)
1141 css_put(&prev->css);
1144 static void __invalidate_reclaim_iterators(struct mem_cgroup *from,
1145 struct mem_cgroup *dead_memcg)
1147 struct mem_cgroup_reclaim_iter *iter;
1148 struct mem_cgroup_per_node *mz;
1151 for_each_node(nid) {
1152 mz = mem_cgroup_nodeinfo(from, nid);
1154 cmpxchg(&iter->position, dead_memcg, NULL);
1158 static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
1160 struct mem_cgroup *memcg = dead_memcg;
1161 struct mem_cgroup *last;
1164 __invalidate_reclaim_iterators(memcg, dead_memcg);
1166 } while ((memcg = parent_mem_cgroup(memcg)));
1169 * When cgruop1 non-hierarchy mode is used,
1170 * parent_mem_cgroup() does not walk all the way up to the
1171 * cgroup root (root_mem_cgroup). So we have to handle
1172 * dead_memcg from cgroup root separately.
1174 if (last != root_mem_cgroup)
1175 __invalidate_reclaim_iterators(root_mem_cgroup,
1180 * mem_cgroup_scan_tasks - iterate over tasks of a memory cgroup hierarchy
1181 * @memcg: hierarchy root
1182 * @fn: function to call for each task
1183 * @arg: argument passed to @fn
1185 * This function iterates over tasks attached to @memcg or to any of its
1186 * descendants and calls @fn for each task. If @fn returns a non-zero
1187 * value, the function breaks the iteration loop and returns the value.
1188 * Otherwise, it will iterate over all tasks and return 0.
1190 * This function must not be called for the root memory cgroup.
1192 int mem_cgroup_scan_tasks(struct mem_cgroup *memcg,
1193 int (*fn)(struct task_struct *, void *), void *arg)
1195 struct mem_cgroup *iter;
1198 BUG_ON(memcg == root_mem_cgroup);
1200 for_each_mem_cgroup_tree(iter, memcg) {
1201 struct css_task_iter it;
1202 struct task_struct *task;
1204 css_task_iter_start(&iter->css, CSS_TASK_ITER_PROCS, &it);
1205 while (!ret && (task = css_task_iter_next(&it)))
1206 ret = fn(task, arg);
1207 css_task_iter_end(&it);
1209 mem_cgroup_iter_break(memcg, iter);
1217 * mem_cgroup_page_lruvec - return lruvec for isolating/putting an LRU page
1219 * @pgdat: pgdat of the page
1221 * This function is only safe when following the LRU page isolation
1222 * and putback protocol: the LRU lock must be held, and the page must
1223 * either be PageLRU() or the caller must have isolated/allocated it.
1225 struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat)
1227 struct mem_cgroup_per_node *mz;
1228 struct mem_cgroup *memcg;
1229 struct lruvec *lruvec;
1231 if (mem_cgroup_disabled()) {
1232 lruvec = &pgdat->__lruvec;
1236 memcg = page->mem_cgroup;
1238 * Swapcache readahead pages are added to the LRU - and
1239 * possibly migrated - before they are charged.
1242 memcg = root_mem_cgroup;
1244 mz = mem_cgroup_page_nodeinfo(memcg, page);
1245 lruvec = &mz->lruvec;
1248 * Since a node can be onlined after the mem_cgroup was created,
1249 * we have to be prepared to initialize lruvec->zone here;
1250 * and if offlined then reonlined, we need to reinitialize it.
1252 if (unlikely(lruvec->pgdat != pgdat))
1253 lruvec->pgdat = pgdat;
1258 * mem_cgroup_update_lru_size - account for adding or removing an lru page
1259 * @lruvec: mem_cgroup per zone lru vector
1260 * @lru: index of lru list the page is sitting on
1261 * @zid: zone id of the accounted pages
1262 * @nr_pages: positive when adding or negative when removing
1264 * This function must be called under lru_lock, just before a page is added
1265 * to or just after a page is removed from an lru list (that ordering being
1266 * so as to allow it to check that lru_size 0 is consistent with list_empty).
1268 void mem_cgroup_update_lru_size(struct lruvec *lruvec, enum lru_list lru,
1269 int zid, int nr_pages)
1271 struct mem_cgroup_per_node *mz;
1272 unsigned long *lru_size;
1275 if (mem_cgroup_disabled())
1278 mz = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
1279 lru_size = &mz->lru_zone_size[zid][lru];
1282 *lru_size += nr_pages;
1285 if (WARN_ONCE(size < 0,
1286 "%s(%p, %d, %d): lru_size %ld\n",
1287 __func__, lruvec, lru, nr_pages, size)) {
1293 *lru_size += nr_pages;
1297 * mem_cgroup_margin - calculate chargeable space of a memory cgroup
1298 * @memcg: the memory cgroup
1300 * Returns the maximum amount of memory @mem can be charged with, in
1303 static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg)
1305 unsigned long margin = 0;
1306 unsigned long count;
1307 unsigned long limit;
1309 count = page_counter_read(&memcg->memory);
1310 limit = READ_ONCE(memcg->memory.max);
1312 margin = limit - count;
1314 if (do_memsw_account()) {
1315 count = page_counter_read(&memcg->memsw);
1316 limit = READ_ONCE(memcg->memsw.max);
1318 margin = min(margin, limit - count);
1327 * A routine for checking "mem" is under move_account() or not.
1329 * Checking a cgroup is mc.from or mc.to or under hierarchy of
1330 * moving cgroups. This is for waiting at high-memory pressure
1333 static bool mem_cgroup_under_move(struct mem_cgroup *memcg)
1335 struct mem_cgroup *from;
1336 struct mem_cgroup *to;
1339 * Unlike task_move routines, we access mc.to, mc.from not under
1340 * mutual exclusion by cgroup_mutex. Here, we take spinlock instead.
1342 spin_lock(&mc.lock);
1348 ret = mem_cgroup_is_descendant(from, memcg) ||
1349 mem_cgroup_is_descendant(to, memcg);
1351 spin_unlock(&mc.lock);
1355 static bool mem_cgroup_wait_acct_move(struct mem_cgroup *memcg)
1357 if (mc.moving_task && current != mc.moving_task) {
1358 if (mem_cgroup_under_move(memcg)) {
1360 prepare_to_wait(&mc.waitq, &wait, TASK_INTERRUPTIBLE);
1361 /* moving charge context might have finished. */
1364 finish_wait(&mc.waitq, &wait);
1371 static char *memory_stat_format(struct mem_cgroup *memcg)
1376 seq_buf_init(&s, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE);
1381 * Provide statistics on the state of the memory subsystem as
1382 * well as cumulative event counters that show past behavior.
1384 * This list is ordered following a combination of these gradients:
1385 * 1) generic big picture -> specifics and details
1386 * 2) reflecting userspace activity -> reflecting kernel heuristics
1388 * Current memory state:
1391 seq_buf_printf(&s, "anon %llu\n",
1392 (u64)memcg_page_state(memcg, MEMCG_RSS) *
1394 seq_buf_printf(&s, "file %llu\n",
1395 (u64)memcg_page_state(memcg, MEMCG_CACHE) *
1397 seq_buf_printf(&s, "kernel_stack %llu\n",
1398 (u64)memcg_page_state(memcg, MEMCG_KERNEL_STACK_KB) *
1400 seq_buf_printf(&s, "slab %llu\n",
1401 (u64)(memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) +
1402 memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE)) *
1404 seq_buf_printf(&s, "sock %llu\n",
1405 (u64)memcg_page_state(memcg, MEMCG_SOCK) *
1408 seq_buf_printf(&s, "shmem %llu\n",
1409 (u64)memcg_page_state(memcg, NR_SHMEM) *
1411 seq_buf_printf(&s, "file_mapped %llu\n",
1412 (u64)memcg_page_state(memcg, NR_FILE_MAPPED) *
1414 seq_buf_printf(&s, "file_dirty %llu\n",
1415 (u64)memcg_page_state(memcg, NR_FILE_DIRTY) *
1417 seq_buf_printf(&s, "file_writeback %llu\n",
1418 (u64)memcg_page_state(memcg, NR_WRITEBACK) *
1422 * TODO: We should eventually replace our own MEMCG_RSS_HUGE counter
1423 * with the NR_ANON_THP vm counter, but right now it's a pain in the
1424 * arse because it requires migrating the work out of rmap to a place
1425 * where the page->mem_cgroup is set up and stable.
1427 seq_buf_printf(&s, "anon_thp %llu\n",
1428 (u64)memcg_page_state(memcg, MEMCG_RSS_HUGE) *
1431 for (i = 0; i < NR_LRU_LISTS; i++)
1432 seq_buf_printf(&s, "%s %llu\n", lru_list_name(i),
1433 (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
1436 seq_buf_printf(&s, "slab_reclaimable %llu\n",
1437 (u64)memcg_page_state(memcg, NR_SLAB_RECLAIMABLE) *
1439 seq_buf_printf(&s, "slab_unreclaimable %llu\n",
1440 (u64)memcg_page_state(memcg, NR_SLAB_UNRECLAIMABLE) *
1443 /* Accumulated memory events */
1445 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGFAULT),
1446 memcg_events(memcg, PGFAULT));
1447 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGMAJFAULT),
1448 memcg_events(memcg, PGMAJFAULT));
1450 seq_buf_printf(&s, "workingset_refault %lu\n",
1451 memcg_page_state(memcg, WORKINGSET_REFAULT));
1452 seq_buf_printf(&s, "workingset_activate %lu\n",
1453 memcg_page_state(memcg, WORKINGSET_ACTIVATE));
1454 seq_buf_printf(&s, "workingset_nodereclaim %lu\n",
1455 memcg_page_state(memcg, WORKINGSET_NODERECLAIM));
1457 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGREFILL),
1458 memcg_events(memcg, PGREFILL));
1459 seq_buf_printf(&s, "pgscan %lu\n",
1460 memcg_events(memcg, PGSCAN_KSWAPD) +
1461 memcg_events(memcg, PGSCAN_DIRECT));
1462 seq_buf_printf(&s, "pgsteal %lu\n",
1463 memcg_events(memcg, PGSTEAL_KSWAPD) +
1464 memcg_events(memcg, PGSTEAL_DIRECT));
1465 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGACTIVATE),
1466 memcg_events(memcg, PGACTIVATE));
1467 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGDEACTIVATE),
1468 memcg_events(memcg, PGDEACTIVATE));
1469 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREE),
1470 memcg_events(memcg, PGLAZYFREE));
1471 seq_buf_printf(&s, "%s %lu\n", vm_event_name(PGLAZYFREED),
1472 memcg_events(memcg, PGLAZYFREED));
1474 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
1475 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_FAULT_ALLOC),
1476 memcg_events(memcg, THP_FAULT_ALLOC));
1477 seq_buf_printf(&s, "%s %lu\n", vm_event_name(THP_COLLAPSE_ALLOC),
1478 memcg_events(memcg, THP_COLLAPSE_ALLOC));
1479 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
1481 /* The above should easily fit into one page */
1482 WARN_ON_ONCE(seq_buf_has_overflowed(&s));
1487 #define K(x) ((x) << (PAGE_SHIFT-10))
1489 * mem_cgroup_print_oom_context: Print OOM information relevant to
1490 * memory controller.
1491 * @memcg: The memory cgroup that went over limit
1492 * @p: Task that is going to be killed
1494 * NOTE: @memcg and @p's mem_cgroup can be different when hierarchy is
1497 void mem_cgroup_print_oom_context(struct mem_cgroup *memcg, struct task_struct *p)
1502 pr_cont(",oom_memcg=");
1503 pr_cont_cgroup_path(memcg->css.cgroup);
1505 pr_cont(",global_oom");
1507 pr_cont(",task_memcg=");
1508 pr_cont_cgroup_path(task_cgroup(p, memory_cgrp_id));
1514 * mem_cgroup_print_oom_meminfo: Print OOM memory information relevant to
1515 * memory controller.
1516 * @memcg: The memory cgroup that went over limit
1518 void mem_cgroup_print_oom_meminfo(struct mem_cgroup *memcg)
1522 pr_info("memory: usage %llukB, limit %llukB, failcnt %lu\n",
1523 K((u64)page_counter_read(&memcg->memory)),
1524 K((u64)memcg->memory.max), memcg->memory.failcnt);
1525 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
1526 pr_info("swap: usage %llukB, limit %llukB, failcnt %lu\n",
1527 K((u64)page_counter_read(&memcg->swap)),
1528 K((u64)memcg->swap.max), memcg->swap.failcnt);
1530 pr_info("memory+swap: usage %llukB, limit %llukB, failcnt %lu\n",
1531 K((u64)page_counter_read(&memcg->memsw)),
1532 K((u64)memcg->memsw.max), memcg->memsw.failcnt);
1533 pr_info("kmem: usage %llukB, limit %llukB, failcnt %lu\n",
1534 K((u64)page_counter_read(&memcg->kmem)),
1535 K((u64)memcg->kmem.max), memcg->kmem.failcnt);
1538 pr_info("Memory cgroup stats for ");
1539 pr_cont_cgroup_path(memcg->css.cgroup);
1541 buf = memory_stat_format(memcg);
1549 * Return the memory (and swap, if configured) limit for a memcg.
1551 unsigned long mem_cgroup_get_max(struct mem_cgroup *memcg)
1555 max = memcg->memory.max;
1556 if (mem_cgroup_swappiness(memcg)) {
1557 unsigned long memsw_max;
1558 unsigned long swap_max;
1560 memsw_max = memcg->memsw.max;
1561 swap_max = memcg->swap.max;
1562 swap_max = min(swap_max, (unsigned long)total_swap_pages);
1563 max = min(max + swap_max, memsw_max);
1568 unsigned long mem_cgroup_size(struct mem_cgroup *memcg)
1570 return page_counter_read(&memcg->memory);
1573 static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
1576 struct oom_control oc = {
1580 .gfp_mask = gfp_mask,
1585 if (mutex_lock_killable(&oom_lock))
1588 * A few threads which were not waiting at mutex_lock_killable() can
1589 * fail to bail out. Therefore, check again after holding oom_lock.
1591 ret = should_force_charge() || out_of_memory(&oc);
1592 mutex_unlock(&oom_lock);
1596 static int mem_cgroup_soft_reclaim(struct mem_cgroup *root_memcg,
1599 unsigned long *total_scanned)
1601 struct mem_cgroup *victim = NULL;
1604 unsigned long excess;
1605 unsigned long nr_scanned;
1606 struct mem_cgroup_reclaim_cookie reclaim = {
1610 excess = soft_limit_excess(root_memcg);
1613 victim = mem_cgroup_iter(root_memcg, victim, &reclaim);
1618 * If we have not been able to reclaim
1619 * anything, it might because there are
1620 * no reclaimable pages under this hierarchy
1625 * We want to do more targeted reclaim.
1626 * excess >> 2 is not to excessive so as to
1627 * reclaim too much, nor too less that we keep
1628 * coming back to reclaim from this cgroup
1630 if (total >= (excess >> 2) ||
1631 (loop > MEM_CGROUP_MAX_RECLAIM_LOOPS))
1636 total += mem_cgroup_shrink_node(victim, gfp_mask, false,
1637 pgdat, &nr_scanned);
1638 *total_scanned += nr_scanned;
1639 if (!soft_limit_excess(root_memcg))
1642 mem_cgroup_iter_break(root_memcg, victim);
1646 #ifdef CONFIG_LOCKDEP
1647 static struct lockdep_map memcg_oom_lock_dep_map = {
1648 .name = "memcg_oom_lock",
1652 static DEFINE_SPINLOCK(memcg_oom_lock);
1655 * Check OOM-Killer is already running under our hierarchy.
1656 * If someone is running, return false.
1658 static bool mem_cgroup_oom_trylock(struct mem_cgroup *memcg)
1660 struct mem_cgroup *iter, *failed = NULL;
1662 spin_lock(&memcg_oom_lock);
1664 for_each_mem_cgroup_tree(iter, memcg) {
1665 if (iter->oom_lock) {
1667 * this subtree of our hierarchy is already locked
1668 * so we cannot give a lock.
1671 mem_cgroup_iter_break(memcg, iter);
1674 iter->oom_lock = true;
1679 * OK, we failed to lock the whole subtree so we have
1680 * to clean up what we set up to the failing subtree
1682 for_each_mem_cgroup_tree(iter, memcg) {
1683 if (iter == failed) {
1684 mem_cgroup_iter_break(memcg, iter);
1687 iter->oom_lock = false;
1690 mutex_acquire(&memcg_oom_lock_dep_map, 0, 1, _RET_IP_);
1692 spin_unlock(&memcg_oom_lock);
1697 static void mem_cgroup_oom_unlock(struct mem_cgroup *memcg)
1699 struct mem_cgroup *iter;
1701 spin_lock(&memcg_oom_lock);
1702 mutex_release(&memcg_oom_lock_dep_map, _RET_IP_);
1703 for_each_mem_cgroup_tree(iter, memcg)
1704 iter->oom_lock = false;
1705 spin_unlock(&memcg_oom_lock);
1708 static void mem_cgroup_mark_under_oom(struct mem_cgroup *memcg)
1710 struct mem_cgroup *iter;
1712 spin_lock(&memcg_oom_lock);
1713 for_each_mem_cgroup_tree(iter, memcg)
1715 spin_unlock(&memcg_oom_lock);
1718 static void mem_cgroup_unmark_under_oom(struct mem_cgroup *memcg)
1720 struct mem_cgroup *iter;
1723 * When a new child is created while the hierarchy is under oom,
1724 * mem_cgroup_oom_lock() may not be called. Watch for underflow.
1726 spin_lock(&memcg_oom_lock);
1727 for_each_mem_cgroup_tree(iter, memcg)
1728 if (iter->under_oom > 0)
1730 spin_unlock(&memcg_oom_lock);
1733 static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq);
1735 struct oom_wait_info {
1736 struct mem_cgroup *memcg;
1737 wait_queue_entry_t wait;
1740 static int memcg_oom_wake_function(wait_queue_entry_t *wait,
1741 unsigned mode, int sync, void *arg)
1743 struct mem_cgroup *wake_memcg = (struct mem_cgroup *)arg;
1744 struct mem_cgroup *oom_wait_memcg;
1745 struct oom_wait_info *oom_wait_info;
1747 oom_wait_info = container_of(wait, struct oom_wait_info, wait);
1748 oom_wait_memcg = oom_wait_info->memcg;
1750 if (!mem_cgroup_is_descendant(wake_memcg, oom_wait_memcg) &&
1751 !mem_cgroup_is_descendant(oom_wait_memcg, wake_memcg))
1753 return autoremove_wake_function(wait, mode, sync, arg);
1756 static void memcg_oom_recover(struct mem_cgroup *memcg)
1759 * For the following lockless ->under_oom test, the only required
1760 * guarantee is that it must see the state asserted by an OOM when
1761 * this function is called as a result of userland actions
1762 * triggered by the notification of the OOM. This is trivially
1763 * achieved by invoking mem_cgroup_mark_under_oom() before
1764 * triggering notification.
1766 if (memcg && memcg->under_oom)
1767 __wake_up(&memcg_oom_waitq, TASK_NORMAL, 0, memcg);
1777 static enum oom_status mem_cgroup_oom(struct mem_cgroup *memcg, gfp_t mask, int order)
1779 enum oom_status ret;
1782 if (order > PAGE_ALLOC_COSTLY_ORDER)
1785 memcg_memory_event(memcg, MEMCG_OOM);
1788 * We are in the middle of the charge context here, so we
1789 * don't want to block when potentially sitting on a callstack
1790 * that holds all kinds of filesystem and mm locks.
1792 * cgroup1 allows disabling the OOM killer and waiting for outside
1793 * handling until the charge can succeed; remember the context and put
1794 * the task to sleep at the end of the page fault when all locks are
1797 * On the other hand, in-kernel OOM killer allows for an async victim
1798 * memory reclaim (oom_reaper) and that means that we are not solely
1799 * relying on the oom victim to make a forward progress and we can
1800 * invoke the oom killer here.
1802 * Please note that mem_cgroup_out_of_memory might fail to find a
1803 * victim and then we have to bail out from the charge path.
1805 if (memcg->oom_kill_disable) {
1806 if (!current->in_user_fault)
1808 css_get(&memcg->css);
1809 current->memcg_in_oom = memcg;
1810 current->memcg_oom_gfp_mask = mask;
1811 current->memcg_oom_order = order;
1816 mem_cgroup_mark_under_oom(memcg);
1818 locked = mem_cgroup_oom_trylock(memcg);
1821 mem_cgroup_oom_notify(memcg);
1823 mem_cgroup_unmark_under_oom(memcg);
1824 if (mem_cgroup_out_of_memory(memcg, mask, order))
1830 mem_cgroup_oom_unlock(memcg);
1836 * mem_cgroup_oom_synchronize - complete memcg OOM handling
1837 * @handle: actually kill/wait or just clean up the OOM state
1839 * This has to be called at the end of a page fault if the memcg OOM
1840 * handler was enabled.
1842 * Memcg supports userspace OOM handling where failed allocations must
1843 * sleep on a waitqueue until the userspace task resolves the
1844 * situation. Sleeping directly in the charge context with all kinds
1845 * of locks held is not a good idea, instead we remember an OOM state
1846 * in the task and mem_cgroup_oom_synchronize() has to be called at
1847 * the end of the page fault to complete the OOM handling.
1849 * Returns %true if an ongoing memcg OOM situation was detected and
1850 * completed, %false otherwise.
1852 bool mem_cgroup_oom_synchronize(bool handle)
1854 struct mem_cgroup *memcg = current->memcg_in_oom;
1855 struct oom_wait_info owait;
1858 /* OOM is global, do not handle */
1865 owait.memcg = memcg;
1866 owait.wait.flags = 0;
1867 owait.wait.func = memcg_oom_wake_function;
1868 owait.wait.private = current;
1869 INIT_LIST_HEAD(&owait.wait.entry);
1871 prepare_to_wait(&memcg_oom_waitq, &owait.wait, TASK_KILLABLE);
1872 mem_cgroup_mark_under_oom(memcg);
1874 locked = mem_cgroup_oom_trylock(memcg);
1877 mem_cgroup_oom_notify(memcg);
1879 if (locked && !memcg->oom_kill_disable) {
1880 mem_cgroup_unmark_under_oom(memcg);
1881 finish_wait(&memcg_oom_waitq, &owait.wait);
1882 mem_cgroup_out_of_memory(memcg, current->memcg_oom_gfp_mask,
1883 current->memcg_oom_order);
1886 mem_cgroup_unmark_under_oom(memcg);
1887 finish_wait(&memcg_oom_waitq, &owait.wait);
1891 mem_cgroup_oom_unlock(memcg);
1893 * There is no guarantee that an OOM-lock contender
1894 * sees the wakeups triggered by the OOM kill
1895 * uncharges. Wake any sleepers explicitely.
1897 memcg_oom_recover(memcg);
1900 current->memcg_in_oom = NULL;
1901 css_put(&memcg->css);
1906 * mem_cgroup_get_oom_group - get a memory cgroup to clean up after OOM
1907 * @victim: task to be killed by the OOM killer
1908 * @oom_domain: memcg in case of memcg OOM, NULL in case of system-wide OOM
1910 * Returns a pointer to a memory cgroup, which has to be cleaned up
1911 * by killing all belonging OOM-killable tasks.
1913 * Caller has to call mem_cgroup_put() on the returned non-NULL memcg.
1915 struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
1916 struct mem_cgroup *oom_domain)
1918 struct mem_cgroup *oom_group = NULL;
1919 struct mem_cgroup *memcg;
1921 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
1925 oom_domain = root_mem_cgroup;
1929 memcg = mem_cgroup_from_task(victim);
1930 if (memcg == root_mem_cgroup)
1934 * Traverse the memory cgroup hierarchy from the victim task's
1935 * cgroup up to the OOMing cgroup (or root) to find the
1936 * highest-level memory cgroup with oom.group set.
1938 for (; memcg; memcg = parent_mem_cgroup(memcg)) {
1939 if (memcg->oom_group)
1942 if (memcg == oom_domain)
1947 css_get(&oom_group->css);
1954 void mem_cgroup_print_oom_group(struct mem_cgroup *memcg)
1956 pr_info("Tasks in ");
1957 pr_cont_cgroup_path(memcg->css.cgroup);
1958 pr_cont(" are going to be killed due to memory.oom.group set\n");
1962 * lock_page_memcg - lock a page->mem_cgroup binding
1965 * This function protects unlocked LRU pages from being moved to
1968 * It ensures lifetime of the returned memcg. Caller is responsible
1969 * for the lifetime of the page; __unlock_page_memcg() is available
1970 * when @page might get freed inside the locked section.
1972 struct mem_cgroup *lock_page_memcg(struct page *page)
1974 struct mem_cgroup *memcg;
1975 unsigned long flags;
1978 * The RCU lock is held throughout the transaction. The fast
1979 * path can get away without acquiring the memcg->move_lock
1980 * because page moving starts with an RCU grace period.
1982 * The RCU lock also protects the memcg from being freed when
1983 * the page state that is going to change is the only thing
1984 * preventing the page itself from being freed. E.g. writeback
1985 * doesn't hold a page reference and relies on PG_writeback to
1986 * keep off truncation, migration and so forth.
1990 if (mem_cgroup_disabled())
1993 memcg = page->mem_cgroup;
1994 if (unlikely(!memcg))
1997 if (atomic_read(&memcg->moving_account) <= 0)
2000 spin_lock_irqsave(&memcg->move_lock, flags);
2001 if (memcg != page->mem_cgroup) {
2002 spin_unlock_irqrestore(&memcg->move_lock, flags);
2007 * When charge migration first begins, we can have locked and
2008 * unlocked page stat updates happening concurrently. Track
2009 * the task who has the lock for unlock_page_memcg().
2011 memcg->move_lock_task = current;
2012 memcg->move_lock_flags = flags;
2016 EXPORT_SYMBOL(lock_page_memcg);
2019 * __unlock_page_memcg - unlock and unpin a memcg
2022 * Unlock and unpin a memcg returned by lock_page_memcg().
2024 void __unlock_page_memcg(struct mem_cgroup *memcg)
2026 if (memcg && memcg->move_lock_task == current) {
2027 unsigned long flags = memcg->move_lock_flags;
2029 memcg->move_lock_task = NULL;
2030 memcg->move_lock_flags = 0;
2032 spin_unlock_irqrestore(&memcg->move_lock, flags);
2039 * unlock_page_memcg - unlock a page->mem_cgroup binding
2042 void unlock_page_memcg(struct page *page)
2044 __unlock_page_memcg(page->mem_cgroup);
2046 EXPORT_SYMBOL(unlock_page_memcg);
2048 struct memcg_stock_pcp {
2049 struct mem_cgroup *cached; /* this never be root cgroup */
2050 unsigned int nr_pages;
2051 struct work_struct work;
2052 unsigned long flags;
2053 #define FLUSHING_CACHED_CHARGE 0
2055 static DEFINE_PER_CPU(struct memcg_stock_pcp, memcg_stock);
2056 static DEFINE_MUTEX(percpu_charge_mutex);
2059 * consume_stock: Try to consume stocked charge on this cpu.
2060 * @memcg: memcg to consume from.
2061 * @nr_pages: how many pages to charge.
2063 * The charges will only happen if @memcg matches the current cpu's memcg
2064 * stock, and at least @nr_pages are available in that stock. Failure to
2065 * service an allocation will refill the stock.
2067 * returns true if successful, false otherwise.
2069 static bool consume_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2071 struct memcg_stock_pcp *stock;
2072 unsigned long flags;
2075 if (nr_pages > MEMCG_CHARGE_BATCH)
2078 local_irq_save(flags);
2080 stock = this_cpu_ptr(&memcg_stock);
2081 if (memcg == stock->cached && stock->nr_pages >= nr_pages) {
2082 stock->nr_pages -= nr_pages;
2086 local_irq_restore(flags);
2092 * Returns stocks cached in percpu and reset cached information.
2094 static void drain_stock(struct memcg_stock_pcp *stock)
2096 struct mem_cgroup *old = stock->cached;
2098 if (stock->nr_pages) {
2099 page_counter_uncharge(&old->memory, stock->nr_pages);
2100 if (do_memsw_account())
2101 page_counter_uncharge(&old->memsw, stock->nr_pages);
2102 css_put_many(&old->css, stock->nr_pages);
2103 stock->nr_pages = 0;
2105 stock->cached = NULL;
2108 static void drain_local_stock(struct work_struct *dummy)
2110 struct memcg_stock_pcp *stock;
2111 unsigned long flags;
2114 * The only protection from memory hotplug vs. drain_stock races is
2115 * that we always operate on local CPU stock here with IRQ disabled
2117 local_irq_save(flags);
2119 stock = this_cpu_ptr(&memcg_stock);
2121 clear_bit(FLUSHING_CACHED_CHARGE, &stock->flags);
2123 local_irq_restore(flags);
2127 * Cache charges(val) to local per_cpu area.
2128 * This will be consumed by consume_stock() function, later.
2130 static void refill_stock(struct mem_cgroup *memcg, unsigned int nr_pages)
2132 struct memcg_stock_pcp *stock;
2133 unsigned long flags;
2135 local_irq_save(flags);
2137 stock = this_cpu_ptr(&memcg_stock);
2138 if (stock->cached != memcg) { /* reset if necessary */
2140 stock->cached = memcg;
2142 stock->nr_pages += nr_pages;
2144 if (stock->nr_pages > MEMCG_CHARGE_BATCH)
2147 local_irq_restore(flags);
2151 * Drains all per-CPU charge caches for given root_memcg resp. subtree
2152 * of the hierarchy under it.
2154 static void drain_all_stock(struct mem_cgroup *root_memcg)
2158 /* If someone's already draining, avoid adding running more workers. */
2159 if (!mutex_trylock(&percpu_charge_mutex))
2162 * Notify other cpus that system-wide "drain" is running
2163 * We do not care about races with the cpu hotplug because cpu down
2164 * as well as workers from this path always operate on the local
2165 * per-cpu data. CPU up doesn't touch memcg_stock at all.
2168 for_each_online_cpu(cpu) {
2169 struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu);
2170 struct mem_cgroup *memcg;
2174 memcg = stock->cached;
2175 if (memcg && stock->nr_pages &&
2176 mem_cgroup_is_descendant(memcg, root_memcg))
2181 !test_and_set_bit(FLUSHING_CACHED_CHARGE, &stock->flags)) {
2183 drain_local_stock(&stock->work);
2185 schedule_work_on(cpu, &stock->work);
2189 mutex_unlock(&percpu_charge_mutex);
2192 static int memcg_hotplug_cpu_dead(unsigned int cpu)
2194 struct memcg_stock_pcp *stock;
2195 struct mem_cgroup *memcg, *mi;
2197 stock = &per_cpu(memcg_stock, cpu);
2200 for_each_mem_cgroup(memcg) {
2203 for (i = 0; i < MEMCG_NR_STAT; i++) {
2207 x = this_cpu_xchg(memcg->vmstats_percpu->stat[i], 0);
2209 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
2210 atomic_long_add(x, &memcg->vmstats[i]);
2212 if (i >= NR_VM_NODE_STAT_ITEMS)
2215 for_each_node(nid) {
2216 struct mem_cgroup_per_node *pn;
2218 pn = mem_cgroup_nodeinfo(memcg, nid);
2219 x = this_cpu_xchg(pn->lruvec_stat_cpu->count[i], 0);
2222 atomic_long_add(x, &pn->lruvec_stat[i]);
2223 } while ((pn = parent_nodeinfo(pn, nid)));
2227 for (i = 0; i < NR_VM_EVENT_ITEMS; i++) {
2230 x = this_cpu_xchg(memcg->vmstats_percpu->events[i], 0);
2232 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
2233 atomic_long_add(x, &memcg->vmevents[i]);
2240 static void reclaim_high(struct mem_cgroup *memcg,
2241 unsigned int nr_pages,
2245 if (page_counter_read(&memcg->memory) <= READ_ONCE(memcg->high))
2247 memcg_memory_event(memcg, MEMCG_HIGH);
2248 try_to_free_mem_cgroup_pages(memcg, nr_pages, gfp_mask, true);
2249 } while ((memcg = parent_mem_cgroup(memcg)));
2252 static void high_work_func(struct work_struct *work)
2254 struct mem_cgroup *memcg;
2256 memcg = container_of(work, struct mem_cgroup, high_work);
2257 reclaim_high(memcg, MEMCG_CHARGE_BATCH, GFP_KERNEL);
2261 * Clamp the maximum sleep time per allocation batch to 2 seconds. This is
2262 * enough to still cause a significant slowdown in most cases, while still
2263 * allowing diagnostics and tracing to proceed without becoming stuck.
2265 #define MEMCG_MAX_HIGH_DELAY_JIFFIES (2UL*HZ)
2268 * When calculating the delay, we use these either side of the exponentiation to
2269 * maintain precision and scale to a reasonable number of jiffies (see the table
2272 * - MEMCG_DELAY_PRECISION_SHIFT: Extra precision bits while translating the
2273 * overage ratio to a delay.
2274 * - MEMCG_DELAY_SCALING_SHIFT: The number of bits to scale down down the
2275 * proposed penalty in order to reduce to a reasonable number of jiffies, and
2276 * to produce a reasonable delay curve.
2278 * MEMCG_DELAY_SCALING_SHIFT just happens to be a number that produces a
2279 * reasonable delay curve compared to precision-adjusted overage, not
2280 * penalising heavily at first, but still making sure that growth beyond the
2281 * limit penalises misbehaviour cgroups by slowing them down exponentially. For
2282 * example, with a high of 100 megabytes:
2284 * +-------+------------------------+
2285 * | usage | time to allocate in ms |
2286 * +-------+------------------------+
2308 * +-------+------------------------+
2310 #define MEMCG_DELAY_PRECISION_SHIFT 20
2311 #define MEMCG_DELAY_SCALING_SHIFT 14
2314 * Get the number of jiffies that we should penalise a mischievous cgroup which
2315 * is exceeding its memory.high by checking both it and its ancestors.
2317 static unsigned long calculate_high_delay(struct mem_cgroup *memcg,
2318 unsigned int nr_pages)
2320 unsigned long penalty_jiffies;
2321 u64 max_overage = 0;
2324 unsigned long usage, high;
2327 usage = page_counter_read(&memcg->memory);
2328 high = READ_ONCE(memcg->high);
2331 * Prevent division by 0 in overage calculation by acting as if
2332 * it was a threshold of 1 page
2334 high = max(high, 1UL);
2336 overage = usage - high;
2337 overage <<= MEMCG_DELAY_PRECISION_SHIFT;
2338 overage = div64_u64(overage, high);
2340 if (overage > max_overage)
2341 max_overage = overage;
2342 } while ((memcg = parent_mem_cgroup(memcg)) &&
2343 !mem_cgroup_is_root(memcg));
2349 * We use overage compared to memory.high to calculate the number of
2350 * jiffies to sleep (penalty_jiffies). Ideally this value should be
2351 * fairly lenient on small overages, and increasingly harsh when the
2352 * memcg in question makes it clear that it has no intention of stopping
2353 * its crazy behaviour, so we exponentially increase the delay based on
2356 penalty_jiffies = max_overage * max_overage * HZ;
2357 penalty_jiffies >>= MEMCG_DELAY_PRECISION_SHIFT;
2358 penalty_jiffies >>= MEMCG_DELAY_SCALING_SHIFT;
2361 * Factor in the task's own contribution to the overage, such that four
2362 * N-sized allocations are throttled approximately the same as one
2363 * 4N-sized allocation.
2365 * MEMCG_CHARGE_BATCH pages is nominal, so work out how much smaller or
2366 * larger the current charge patch is than that.
2368 penalty_jiffies = penalty_jiffies * nr_pages / MEMCG_CHARGE_BATCH;
2371 * Clamp the max delay per usermode return so as to still keep the
2372 * application moving forwards and also permit diagnostics, albeit
2375 return min(penalty_jiffies, MEMCG_MAX_HIGH_DELAY_JIFFIES);
2379 * Scheduled by try_charge() to be executed from the userland return path
2380 * and reclaims memory over the high limit.
2382 void mem_cgroup_handle_over_high(void)
2384 unsigned long penalty_jiffies;
2385 unsigned long pflags;
2386 unsigned int nr_pages = current->memcg_nr_pages_over_high;
2387 struct mem_cgroup *memcg;
2389 if (likely(!nr_pages))
2392 memcg = get_mem_cgroup_from_mm(current->mm);
2393 reclaim_high(memcg, nr_pages, GFP_KERNEL);
2394 current->memcg_nr_pages_over_high = 0;
2397 * memory.high is breached and reclaim is unable to keep up. Throttle
2398 * allocators proactively to slow down excessive growth.
2400 penalty_jiffies = calculate_high_delay(memcg, nr_pages);
2403 * Don't sleep if the amount of jiffies this memcg owes us is so low
2404 * that it's not even worth doing, in an attempt to be nice to those who
2405 * go only a small amount over their memory.high value and maybe haven't
2406 * been aggressively reclaimed enough yet.
2408 if (penalty_jiffies <= HZ / 100)
2412 * If we exit early, we're guaranteed to die (since
2413 * schedule_timeout_killable sets TASK_KILLABLE). This means we don't
2414 * need to account for any ill-begotten jiffies to pay them off later.
2416 psi_memstall_enter(&pflags);
2417 schedule_timeout_killable(penalty_jiffies);
2418 psi_memstall_leave(&pflags);
2421 css_put(&memcg->css);
2424 static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask,
2425 unsigned int nr_pages)
2427 unsigned int batch = max(MEMCG_CHARGE_BATCH, nr_pages);
2428 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2429 struct mem_cgroup *mem_over_limit;
2430 struct page_counter *counter;
2431 unsigned long nr_reclaimed;
2432 bool may_swap = true;
2433 bool drained = false;
2434 enum oom_status oom_status;
2436 if (mem_cgroup_is_root(memcg))
2439 if (consume_stock(memcg, nr_pages))
2442 if (!do_memsw_account() ||
2443 page_counter_try_charge(&memcg->memsw, batch, &counter)) {
2444 if (page_counter_try_charge(&memcg->memory, batch, &counter))
2446 if (do_memsw_account())
2447 page_counter_uncharge(&memcg->memsw, batch);
2448 mem_over_limit = mem_cgroup_from_counter(counter, memory);
2450 mem_over_limit = mem_cgroup_from_counter(counter, memsw);
2454 if (batch > nr_pages) {
2460 * Memcg doesn't have a dedicated reserve for atomic
2461 * allocations. But like the global atomic pool, we need to
2462 * put the burden of reclaim on regular allocation requests
2463 * and let these go through as privileged allocations.
2465 if (gfp_mask & __GFP_ATOMIC)
2469 * Unlike in global OOM situations, memcg is not in a physical
2470 * memory shortage. Allow dying and OOM-killed tasks to
2471 * bypass the last charges so that they can exit quickly and
2472 * free their memory.
2474 if (unlikely(should_force_charge()))
2478 * Prevent unbounded recursion when reclaim operations need to
2479 * allocate memory. This might exceed the limits temporarily,
2480 * but we prefer facilitating memory reclaim and getting back
2481 * under the limit over triggering OOM kills in these cases.
2483 if (unlikely(current->flags & PF_MEMALLOC))
2486 if (unlikely(task_in_memcg_oom(current)))
2489 if (!gfpflags_allow_blocking(gfp_mask))
2492 memcg_memory_event(mem_over_limit, MEMCG_MAX);
2494 nr_reclaimed = try_to_free_mem_cgroup_pages(mem_over_limit, nr_pages,
2495 gfp_mask, may_swap);
2497 if (mem_cgroup_margin(mem_over_limit) >= nr_pages)
2501 drain_all_stock(mem_over_limit);
2506 if (gfp_mask & __GFP_NORETRY)
2509 * Even though the limit is exceeded at this point, reclaim
2510 * may have been able to free some pages. Retry the charge
2511 * before killing the task.
2513 * Only for regular pages, though: huge pages are rather
2514 * unlikely to succeed so close to the limit, and we fall back
2515 * to regular pages anyway in case of failure.
2517 if (nr_reclaimed && nr_pages <= (1 << PAGE_ALLOC_COSTLY_ORDER))
2520 * At task move, charge accounts can be doubly counted. So, it's
2521 * better to wait until the end of task_move if something is going on.
2523 if (mem_cgroup_wait_acct_move(mem_over_limit))
2529 if (gfp_mask & __GFP_RETRY_MAYFAIL)
2532 if (gfp_mask & __GFP_NOFAIL)
2535 if (fatal_signal_pending(current))
2539 * keep retrying as long as the memcg oom killer is able to make
2540 * a forward progress or bypass the charge if the oom killer
2541 * couldn't make any progress.
2543 oom_status = mem_cgroup_oom(mem_over_limit, gfp_mask,
2544 get_order(nr_pages * PAGE_SIZE));
2545 switch (oom_status) {
2547 nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
2555 if (!(gfp_mask & __GFP_NOFAIL))
2559 * The allocation either can't fail or will lead to more memory
2560 * being freed very soon. Allow memory usage go over the limit
2561 * temporarily by force charging it.
2563 page_counter_charge(&memcg->memory, nr_pages);
2564 if (do_memsw_account())
2565 page_counter_charge(&memcg->memsw, nr_pages);
2566 css_get_many(&memcg->css, nr_pages);
2571 css_get_many(&memcg->css, batch);
2572 if (batch > nr_pages)
2573 refill_stock(memcg, batch - nr_pages);
2576 * If the hierarchy is above the normal consumption range, schedule
2577 * reclaim on returning to userland. We can perform reclaim here
2578 * if __GFP_RECLAIM but let's always punt for simplicity and so that
2579 * GFP_KERNEL can consistently be used during reclaim. @memcg is
2580 * not recorded as it most likely matches current's and won't
2581 * change in the meantime. As high limit is checked again before
2582 * reclaim, the cost of mismatch is negligible.
2585 if (page_counter_read(&memcg->memory) > READ_ONCE(memcg->high)) {
2586 /* Don't bother a random interrupted task */
2587 if (in_interrupt()) {
2588 schedule_work(&memcg->high_work);
2591 current->memcg_nr_pages_over_high += batch;
2592 set_notify_resume(current);
2595 } while ((memcg = parent_mem_cgroup(memcg)));
2600 static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages)
2602 if (mem_cgroup_is_root(memcg))
2605 page_counter_uncharge(&memcg->memory, nr_pages);
2606 if (do_memsw_account())
2607 page_counter_uncharge(&memcg->memsw, nr_pages);
2609 css_put_many(&memcg->css, nr_pages);
2612 static void lock_page_lru(struct page *page, int *isolated)
2614 pg_data_t *pgdat = page_pgdat(page);
2616 spin_lock_irq(&pgdat->lru_lock);
2617 if (PageLRU(page)) {
2618 struct lruvec *lruvec;
2620 lruvec = mem_cgroup_page_lruvec(page, pgdat);
2622 del_page_from_lru_list(page, lruvec, page_lru(page));
2628 static void unlock_page_lru(struct page *page, int isolated)
2630 pg_data_t *pgdat = page_pgdat(page);
2633 struct lruvec *lruvec;
2635 lruvec = mem_cgroup_page_lruvec(page, pgdat);
2636 VM_BUG_ON_PAGE(PageLRU(page), page);
2638 add_page_to_lru_list(page, lruvec, page_lru(page));
2640 spin_unlock_irq(&pgdat->lru_lock);
2643 static void commit_charge(struct page *page, struct mem_cgroup *memcg,
2648 VM_BUG_ON_PAGE(page->mem_cgroup, page);
2651 * In some cases, SwapCache and FUSE(splice_buf->radixtree), the page
2652 * may already be on some other mem_cgroup's LRU. Take care of it.
2655 lock_page_lru(page, &isolated);
2658 * Nobody should be changing or seriously looking at
2659 * page->mem_cgroup at this point:
2661 * - the page is uncharged
2663 * - the page is off-LRU
2665 * - an anonymous fault has exclusive page access, except for
2666 * a locked page table
2668 * - a page cache insertion, a swapin fault, or a migration
2669 * have the page locked
2671 page->mem_cgroup = memcg;
2674 unlock_page_lru(page, isolated);
2677 #ifdef CONFIG_MEMCG_KMEM
2679 * Returns a pointer to the memory cgroup to which the kernel object is charged.
2681 * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
2682 * cgroup_mutex, etc.
2684 struct mem_cgroup *mem_cgroup_from_obj(void *p)
2688 if (mem_cgroup_disabled())
2691 page = virt_to_head_page(p);
2694 * Slab pages don't have page->mem_cgroup set because corresponding
2695 * kmem caches can be reparented during the lifetime. That's why
2696 * memcg_from_slab_page() should be used instead.
2699 return memcg_from_slab_page(page);
2701 /* All other pages use page->mem_cgroup */
2702 return page->mem_cgroup;
2705 static int memcg_alloc_cache_id(void)
2710 id = ida_simple_get(&memcg_cache_ida,
2711 0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
2715 if (id < memcg_nr_cache_ids)
2719 * There's no space for the new id in memcg_caches arrays,
2720 * so we have to grow them.
2722 down_write(&memcg_cache_ids_sem);
2724 size = 2 * (id + 1);
2725 if (size < MEMCG_CACHES_MIN_SIZE)
2726 size = MEMCG_CACHES_MIN_SIZE;
2727 else if (size > MEMCG_CACHES_MAX_SIZE)
2728 size = MEMCG_CACHES_MAX_SIZE;
2730 err = memcg_update_all_caches(size);
2732 err = memcg_update_all_list_lrus(size);
2734 memcg_nr_cache_ids = size;
2736 up_write(&memcg_cache_ids_sem);
2739 ida_simple_remove(&memcg_cache_ida, id);
2745 static void memcg_free_cache_id(int id)
2747 ida_simple_remove(&memcg_cache_ida, id);
2750 struct memcg_kmem_cache_create_work {
2751 struct mem_cgroup *memcg;
2752 struct kmem_cache *cachep;
2753 struct work_struct work;
2756 static void memcg_kmem_cache_create_func(struct work_struct *w)
2758 struct memcg_kmem_cache_create_work *cw =
2759 container_of(w, struct memcg_kmem_cache_create_work, work);
2760 struct mem_cgroup *memcg = cw->memcg;
2761 struct kmem_cache *cachep = cw->cachep;
2763 memcg_create_kmem_cache(memcg, cachep);
2765 css_put(&memcg->css);
2770 * Enqueue the creation of a per-memcg kmem_cache.
2772 static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg,
2773 struct kmem_cache *cachep)
2775 struct memcg_kmem_cache_create_work *cw;
2777 if (!css_tryget_online(&memcg->css))
2780 cw = kmalloc(sizeof(*cw), GFP_NOWAIT | __GFP_NOWARN);
2785 cw->cachep = cachep;
2786 INIT_WORK(&cw->work, memcg_kmem_cache_create_func);
2788 queue_work(memcg_kmem_cache_wq, &cw->work);
2791 static inline bool memcg_kmem_bypass(void)
2793 if (in_interrupt() || !current->mm || (current->flags & PF_KTHREAD))
2799 * memcg_kmem_get_cache: select the correct per-memcg cache for allocation
2800 * @cachep: the original global kmem cache
2802 * Return the kmem_cache we're supposed to use for a slab allocation.
2803 * We try to use the current memcg's version of the cache.
2805 * If the cache does not exist yet, if we are the first user of it, we
2806 * create it asynchronously in a workqueue and let the current allocation
2807 * go through with the original cache.
2809 * This function takes a reference to the cache it returns to assure it
2810 * won't get destroyed while we are working with it. Once the caller is
2811 * done with it, memcg_kmem_put_cache() must be called to release the
2814 struct kmem_cache *memcg_kmem_get_cache(struct kmem_cache *cachep)
2816 struct mem_cgroup *memcg;
2817 struct kmem_cache *memcg_cachep;
2818 struct memcg_cache_array *arr;
2821 VM_BUG_ON(!is_root_cache(cachep));
2823 if (memcg_kmem_bypass())
2828 if (unlikely(current->active_memcg))
2829 memcg = current->active_memcg;
2831 memcg = mem_cgroup_from_task(current);
2833 if (!memcg || memcg == root_mem_cgroup)
2836 kmemcg_id = READ_ONCE(memcg->kmemcg_id);
2840 arr = rcu_dereference(cachep->memcg_params.memcg_caches);
2843 * Make sure we will access the up-to-date value. The code updating
2844 * memcg_caches issues a write barrier to match the data dependency
2845 * barrier inside READ_ONCE() (see memcg_create_kmem_cache()).
2847 memcg_cachep = READ_ONCE(arr->entries[kmemcg_id]);
2850 * If we are in a safe context (can wait, and not in interrupt
2851 * context), we could be be predictable and return right away.
2852 * This would guarantee that the allocation being performed
2853 * already belongs in the new cache.
2855 * However, there are some clashes that can arrive from locking.
2856 * For instance, because we acquire the slab_mutex while doing
2857 * memcg_create_kmem_cache, this means no further allocation
2858 * could happen with the slab_mutex held. So it's better to
2861 * If the memcg is dying or memcg_cache is about to be released,
2862 * don't bother creating new kmem_caches. Because memcg_cachep
2863 * is ZEROed as the fist step of kmem offlining, we don't need
2864 * percpu_ref_tryget_live() here. css_tryget_online() check in
2865 * memcg_schedule_kmem_cache_create() will prevent us from
2866 * creation of a new kmem_cache.
2868 if (unlikely(!memcg_cachep))
2869 memcg_schedule_kmem_cache_create(memcg, cachep);
2870 else if (percpu_ref_tryget(&memcg_cachep->memcg_params.refcnt))
2871 cachep = memcg_cachep;
2878 * memcg_kmem_put_cache: drop reference taken by memcg_kmem_get_cache
2879 * @cachep: the cache returned by memcg_kmem_get_cache
2881 void memcg_kmem_put_cache(struct kmem_cache *cachep)
2883 if (!is_root_cache(cachep))
2884 percpu_ref_put(&cachep->memcg_params.refcnt);
2888 * __memcg_kmem_charge: charge a number of kernel pages to a memcg
2889 * @memcg: memory cgroup to charge
2890 * @gfp: reclaim mode
2891 * @nr_pages: number of pages to charge
2893 * Returns 0 on success, an error code on failure.
2895 int __memcg_kmem_charge(struct mem_cgroup *memcg, gfp_t gfp,
2896 unsigned int nr_pages)
2898 struct page_counter *counter;
2901 ret = try_charge(memcg, gfp, nr_pages);
2905 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
2906 !page_counter_try_charge(&memcg->kmem, nr_pages, &counter)) {
2909 * Enforce __GFP_NOFAIL allocation because callers are not
2910 * prepared to see failures and likely do not have any failure
2913 if (gfp & __GFP_NOFAIL) {
2914 page_counter_charge(&memcg->kmem, nr_pages);
2917 cancel_charge(memcg, nr_pages);
2924 * __memcg_kmem_uncharge: uncharge a number of kernel pages from a memcg
2925 * @memcg: memcg to uncharge
2926 * @nr_pages: number of pages to uncharge
2928 void __memcg_kmem_uncharge(struct mem_cgroup *memcg, unsigned int nr_pages)
2930 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
2931 page_counter_uncharge(&memcg->kmem, nr_pages);
2933 page_counter_uncharge(&memcg->memory, nr_pages);
2934 if (do_memsw_account())
2935 page_counter_uncharge(&memcg->memsw, nr_pages);
2939 * __memcg_kmem_charge_page: charge a kmem page to the current memory cgroup
2940 * @page: page to charge
2941 * @gfp: reclaim mode
2942 * @order: allocation order
2944 * Returns 0 on success, an error code on failure.
2946 int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
2948 struct mem_cgroup *memcg;
2951 if (memcg_kmem_bypass())
2954 memcg = get_mem_cgroup_from_current();
2955 if (!mem_cgroup_is_root(memcg)) {
2956 ret = __memcg_kmem_charge(memcg, gfp, 1 << order);
2958 page->mem_cgroup = memcg;
2959 __SetPageKmemcg(page);
2962 css_put(&memcg->css);
2967 * __memcg_kmem_uncharge_page: uncharge a kmem page
2968 * @page: page to uncharge
2969 * @order: allocation order
2971 void __memcg_kmem_uncharge_page(struct page *page, int order)
2973 struct mem_cgroup *memcg = page->mem_cgroup;
2974 unsigned int nr_pages = 1 << order;
2979 VM_BUG_ON_PAGE(mem_cgroup_is_root(memcg), page);
2980 __memcg_kmem_uncharge(memcg, nr_pages);
2981 page->mem_cgroup = NULL;
2983 /* slab pages do not have PageKmemcg flag set */
2984 if (PageKmemcg(page))
2985 __ClearPageKmemcg(page);
2987 css_put_many(&memcg->css, nr_pages);
2989 #endif /* CONFIG_MEMCG_KMEM */
2991 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
2994 * Because tail pages are not marked as "used", set it. We're under
2995 * pgdat->lru_lock and migration entries setup in all page mappings.
2997 void mem_cgroup_split_huge_fixup(struct page *head)
3001 if (mem_cgroup_disabled())
3004 for (i = 1; i < HPAGE_PMD_NR; i++)
3005 head[i].mem_cgroup = head->mem_cgroup;
3007 __mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PMD_NR);
3009 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
3011 #ifdef CONFIG_MEMCG_SWAP
3013 * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record.
3014 * @entry: swap entry to be moved
3015 * @from: mem_cgroup which the entry is moved from
3016 * @to: mem_cgroup which the entry is moved to
3018 * It succeeds only when the swap_cgroup's record for this entry is the same
3019 * as the mem_cgroup's id of @from.
3021 * Returns 0 on success, -EINVAL on failure.
3023 * The caller must have charged to @to, IOW, called page_counter_charge() about
3024 * both res and memsw, and called css_get().
3026 static int mem_cgroup_move_swap_account(swp_entry_t entry,
3027 struct mem_cgroup *from, struct mem_cgroup *to)
3029 unsigned short old_id, new_id;
3031 old_id = mem_cgroup_id(from);
3032 new_id = mem_cgroup_id(to);
3034 if (swap_cgroup_cmpxchg(entry, old_id, new_id) == old_id) {
3035 mod_memcg_state(from, MEMCG_SWAP, -1);
3036 mod_memcg_state(to, MEMCG_SWAP, 1);
3042 static inline int mem_cgroup_move_swap_account(swp_entry_t entry,
3043 struct mem_cgroup *from, struct mem_cgroup *to)
3049 static DEFINE_MUTEX(memcg_max_mutex);
3051 static int mem_cgroup_resize_max(struct mem_cgroup *memcg,
3052 unsigned long max, bool memsw)
3054 bool enlarge = false;
3055 bool drained = false;
3057 bool limits_invariant;
3058 struct page_counter *counter = memsw ? &memcg->memsw : &memcg->memory;
3061 if (signal_pending(current)) {
3066 mutex_lock(&memcg_max_mutex);
3068 * Make sure that the new limit (memsw or memory limit) doesn't
3069 * break our basic invariant rule memory.max <= memsw.max.
3071 limits_invariant = memsw ? max >= memcg->memory.max :
3072 max <= memcg->memsw.max;
3073 if (!limits_invariant) {
3074 mutex_unlock(&memcg_max_mutex);
3078 if (max > counter->max)
3080 ret = page_counter_set_max(counter, max);
3081 mutex_unlock(&memcg_max_mutex);
3087 drain_all_stock(memcg);
3092 if (!try_to_free_mem_cgroup_pages(memcg, 1,
3093 GFP_KERNEL, !memsw)) {
3099 if (!ret && enlarge)
3100 memcg_oom_recover(memcg);
3105 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
3107 unsigned long *total_scanned)
3109 unsigned long nr_reclaimed = 0;
3110 struct mem_cgroup_per_node *mz, *next_mz = NULL;
3111 unsigned long reclaimed;
3113 struct mem_cgroup_tree_per_node *mctz;
3114 unsigned long excess;
3115 unsigned long nr_scanned;
3120 mctz = soft_limit_tree_node(pgdat->node_id);
3123 * Do not even bother to check the largest node if the root
3124 * is empty. Do it lockless to prevent lock bouncing. Races
3125 * are acceptable as soft limit is best effort anyway.
3127 if (!mctz || RB_EMPTY_ROOT(&mctz->rb_root))
3131 * This loop can run a while, specially if mem_cgroup's continuously
3132 * keep exceeding their soft limit and putting the system under
3139 mz = mem_cgroup_largest_soft_limit_node(mctz);
3144 reclaimed = mem_cgroup_soft_reclaim(mz->memcg, pgdat,
3145 gfp_mask, &nr_scanned);
3146 nr_reclaimed += reclaimed;
3147 *total_scanned += nr_scanned;
3148 spin_lock_irq(&mctz->lock);
3149 __mem_cgroup_remove_exceeded(mz, mctz);
3152 * If we failed to reclaim anything from this memory cgroup
3153 * it is time to move on to the next cgroup
3157 next_mz = __mem_cgroup_largest_soft_limit_node(mctz);
3159 excess = soft_limit_excess(mz->memcg);
3161 * One school of thought says that we should not add
3162 * back the node to the tree if reclaim returns 0.
3163 * But our reclaim could return 0, simply because due
3164 * to priority we are exposing a smaller subset of
3165 * memory to reclaim from. Consider this as a longer
3168 /* If excess == 0, no tree ops */
3169 __mem_cgroup_insert_exceeded(mz, mctz, excess);
3170 spin_unlock_irq(&mctz->lock);
3171 css_put(&mz->memcg->css);
3174 * Could not reclaim anything and there are no more
3175 * mem cgroups to try or we seem to be looping without
3176 * reclaiming anything.
3178 if (!nr_reclaimed &&
3180 loop > MEM_CGROUP_MAX_SOFT_LIMIT_RECLAIM_LOOPS))
3182 } while (!nr_reclaimed);
3184 css_put(&next_mz->memcg->css);
3185 return nr_reclaimed;
3189 * Test whether @memcg has children, dead or alive. Note that this
3190 * function doesn't care whether @memcg has use_hierarchy enabled and
3191 * returns %true if there are child csses according to the cgroup
3192 * hierarchy. Testing use_hierarchy is the caller's responsiblity.
3194 static inline bool memcg_has_children(struct mem_cgroup *memcg)
3199 ret = css_next_child(NULL, &memcg->css);
3205 * Reclaims as many pages from the given memcg as possible.
3207 * Caller is responsible for holding css reference for memcg.
3209 static int mem_cgroup_force_empty(struct mem_cgroup *memcg)
3211 int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
3213 /* we call try-to-free pages for make this cgroup empty */
3214 lru_add_drain_all();
3216 drain_all_stock(memcg);
3218 /* try to free all pages in this cgroup */
3219 while (nr_retries && page_counter_read(&memcg->memory)) {
3222 if (signal_pending(current))
3225 progress = try_to_free_mem_cgroup_pages(memcg, 1,
3229 /* maybe some writeback is necessary */
3230 congestion_wait(BLK_RW_ASYNC, HZ/10);
3238 static ssize_t mem_cgroup_force_empty_write(struct kernfs_open_file *of,
3239 char *buf, size_t nbytes,
3242 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3244 if (mem_cgroup_is_root(memcg))
3246 return mem_cgroup_force_empty(memcg) ?: nbytes;
3249 static u64 mem_cgroup_hierarchy_read(struct cgroup_subsys_state *css,
3252 return mem_cgroup_from_css(css)->use_hierarchy;
3255 static int mem_cgroup_hierarchy_write(struct cgroup_subsys_state *css,
3256 struct cftype *cft, u64 val)
3259 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3260 struct mem_cgroup *parent_memcg = mem_cgroup_from_css(memcg->css.parent);
3262 if (memcg->use_hierarchy == val)
3266 * If parent's use_hierarchy is set, we can't make any modifications
3267 * in the child subtrees. If it is unset, then the change can
3268 * occur, provided the current cgroup has no children.
3270 * For the root cgroup, parent_mem is NULL, we allow value to be
3271 * set if there are no children.
3273 if ((!parent_memcg || !parent_memcg->use_hierarchy) &&
3274 (val == 1 || val == 0)) {
3275 if (!memcg_has_children(memcg))
3276 memcg->use_hierarchy = val;
3285 static unsigned long mem_cgroup_usage(struct mem_cgroup *memcg, bool swap)
3289 if (mem_cgroup_is_root(memcg)) {
3290 val = memcg_page_state(memcg, MEMCG_CACHE) +
3291 memcg_page_state(memcg, MEMCG_RSS);
3293 val += memcg_page_state(memcg, MEMCG_SWAP);
3296 val = page_counter_read(&memcg->memory);
3298 val = page_counter_read(&memcg->memsw);
3311 static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
3314 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3315 struct page_counter *counter;
3317 switch (MEMFILE_TYPE(cft->private)) {
3319 counter = &memcg->memory;
3322 counter = &memcg->memsw;
3325 counter = &memcg->kmem;
3328 counter = &memcg->tcpmem;
3334 switch (MEMFILE_ATTR(cft->private)) {
3336 if (counter == &memcg->memory)
3337 return (u64)mem_cgroup_usage(memcg, false) * PAGE_SIZE;
3338 if (counter == &memcg->memsw)
3339 return (u64)mem_cgroup_usage(memcg, true) * PAGE_SIZE;
3340 return (u64)page_counter_read(counter) * PAGE_SIZE;
3342 return (u64)counter->max * PAGE_SIZE;
3344 return (u64)counter->watermark * PAGE_SIZE;
3346 return counter->failcnt;
3347 case RES_SOFT_LIMIT:
3348 return (u64)memcg->soft_limit * PAGE_SIZE;
3354 static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg)
3356 unsigned long stat[MEMCG_NR_STAT] = {0};
3357 struct mem_cgroup *mi;
3360 for_each_online_cpu(cpu)
3361 for (i = 0; i < MEMCG_NR_STAT; i++)
3362 stat[i] += per_cpu(memcg->vmstats_percpu->stat[i], cpu);
3364 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
3365 for (i = 0; i < MEMCG_NR_STAT; i++)
3366 atomic_long_add(stat[i], &mi->vmstats[i]);
3368 for_each_node(node) {
3369 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
3370 struct mem_cgroup_per_node *pi;
3372 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
3375 for_each_online_cpu(cpu)
3376 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
3378 pn->lruvec_stat_cpu->count[i], cpu);
3380 for (pi = pn; pi; pi = parent_nodeinfo(pi, node))
3381 for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
3382 atomic_long_add(stat[i], &pi->lruvec_stat[i]);
3386 static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg)
3388 unsigned long events[NR_VM_EVENT_ITEMS];
3389 struct mem_cgroup *mi;
3392 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
3395 for_each_online_cpu(cpu)
3396 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
3397 events[i] += per_cpu(memcg->vmstats_percpu->events[i],
3400 for (mi = memcg; mi; mi = parent_mem_cgroup(mi))
3401 for (i = 0; i < NR_VM_EVENT_ITEMS; i++)
3402 atomic_long_add(events[i], &mi->vmevents[i]);
3405 #ifdef CONFIG_MEMCG_KMEM
3406 static int memcg_online_kmem(struct mem_cgroup *memcg)
3410 if (cgroup_memory_nokmem)
3413 BUG_ON(memcg->kmemcg_id >= 0);
3414 BUG_ON(memcg->kmem_state);
3416 memcg_id = memcg_alloc_cache_id();
3420 static_branch_inc(&memcg_kmem_enabled_key);
3422 * A memory cgroup is considered kmem-online as soon as it gets
3423 * kmemcg_id. Setting the id after enabling static branching will
3424 * guarantee no one starts accounting before all call sites are
3427 memcg->kmemcg_id = memcg_id;
3428 memcg->kmem_state = KMEM_ONLINE;
3429 INIT_LIST_HEAD(&memcg->kmem_caches);
3434 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3436 struct cgroup_subsys_state *css;
3437 struct mem_cgroup *parent, *child;
3440 if (memcg->kmem_state != KMEM_ONLINE)
3443 * Clear the online state before clearing memcg_caches array
3444 * entries. The slab_mutex in memcg_deactivate_kmem_caches()
3445 * guarantees that no cache will be created for this cgroup
3446 * after we are done (see memcg_create_kmem_cache()).
3448 memcg->kmem_state = KMEM_ALLOCATED;
3450 parent = parent_mem_cgroup(memcg);
3452 parent = root_mem_cgroup;
3455 * Deactivate and reparent kmem_caches.
3457 memcg_deactivate_kmem_caches(memcg, parent);
3459 kmemcg_id = memcg->kmemcg_id;
3460 BUG_ON(kmemcg_id < 0);
3463 * Change kmemcg_id of this cgroup and all its descendants to the
3464 * parent's id, and then move all entries from this cgroup's list_lrus
3465 * to ones of the parent. After we have finished, all list_lrus
3466 * corresponding to this cgroup are guaranteed to remain empty. The
3467 * ordering is imposed by list_lru_node->lock taken by
3468 * memcg_drain_all_list_lrus().
3470 rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
3471 css_for_each_descendant_pre(css, &memcg->css) {
3472 child = mem_cgroup_from_css(css);
3473 BUG_ON(child->kmemcg_id != kmemcg_id);
3474 child->kmemcg_id = parent->kmemcg_id;
3475 if (!memcg->use_hierarchy)
3480 memcg_drain_all_list_lrus(kmemcg_id, parent);
3482 memcg_free_cache_id(kmemcg_id);
3485 static void memcg_free_kmem(struct mem_cgroup *memcg)
3487 /* css_alloc() failed, offlining didn't happen */
3488 if (unlikely(memcg->kmem_state == KMEM_ONLINE))
3489 memcg_offline_kmem(memcg);
3491 if (memcg->kmem_state == KMEM_ALLOCATED) {
3492 WARN_ON(!list_empty(&memcg->kmem_caches));
3493 static_branch_dec(&memcg_kmem_enabled_key);
3497 static int memcg_online_kmem(struct mem_cgroup *memcg)
3501 static void memcg_offline_kmem(struct mem_cgroup *memcg)
3504 static void memcg_free_kmem(struct mem_cgroup *memcg)
3507 #endif /* CONFIG_MEMCG_KMEM */
3509 static int memcg_update_kmem_max(struct mem_cgroup *memcg,
3514 mutex_lock(&memcg_max_mutex);
3515 ret = page_counter_set_max(&memcg->kmem, max);
3516 mutex_unlock(&memcg_max_mutex);
3520 static int memcg_update_tcp_max(struct mem_cgroup *memcg, unsigned long max)
3524 mutex_lock(&memcg_max_mutex);
3526 ret = page_counter_set_max(&memcg->tcpmem, max);
3530 if (!memcg->tcpmem_active) {
3532 * The active flag needs to be written after the static_key
3533 * update. This is what guarantees that the socket activation
3534 * function is the last one to run. See mem_cgroup_sk_alloc()
3535 * for details, and note that we don't mark any socket as
3536 * belonging to this memcg until that flag is up.
3538 * We need to do this, because static_keys will span multiple
3539 * sites, but we can't control their order. If we mark a socket
3540 * as accounted, but the accounting functions are not patched in
3541 * yet, we'll lose accounting.
3543 * We never race with the readers in mem_cgroup_sk_alloc(),
3544 * because when this value change, the code to process it is not
3547 static_branch_inc(&memcg_sockets_enabled_key);
3548 memcg->tcpmem_active = true;
3551 mutex_unlock(&memcg_max_mutex);
3556 * The user of this function is...
3559 static ssize_t mem_cgroup_write(struct kernfs_open_file *of,
3560 char *buf, size_t nbytes, loff_t off)
3562 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3563 unsigned long nr_pages;
3566 buf = strstrip(buf);
3567 ret = page_counter_memparse(buf, "-1", &nr_pages);
3571 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3573 if (mem_cgroup_is_root(memcg)) { /* Can't set limit on root */
3577 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3579 ret = mem_cgroup_resize_max(memcg, nr_pages, false);
3582 ret = mem_cgroup_resize_max(memcg, nr_pages, true);
3585 pr_warn_once("kmem.limit_in_bytes is deprecated and will be removed. "
3586 "Please report your usecase to linux-mm@kvack.org if you "
3587 "depend on this functionality.\n");
3588 ret = memcg_update_kmem_max(memcg, nr_pages);
3591 ret = memcg_update_tcp_max(memcg, nr_pages);
3595 case RES_SOFT_LIMIT:
3596 memcg->soft_limit = nr_pages;
3600 return ret ?: nbytes;
3603 static ssize_t mem_cgroup_reset(struct kernfs_open_file *of, char *buf,
3604 size_t nbytes, loff_t off)
3606 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
3607 struct page_counter *counter;
3609 switch (MEMFILE_TYPE(of_cft(of)->private)) {
3611 counter = &memcg->memory;
3614 counter = &memcg->memsw;
3617 counter = &memcg->kmem;
3620 counter = &memcg->tcpmem;
3626 switch (MEMFILE_ATTR(of_cft(of)->private)) {
3628 page_counter_reset_watermark(counter);
3631 counter->failcnt = 0;
3640 static u64 mem_cgroup_move_charge_read(struct cgroup_subsys_state *css,
3643 return mem_cgroup_from_css(css)->move_charge_at_immigrate;
3647 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3648 struct cftype *cft, u64 val)
3650 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3652 if (val & ~MOVE_MASK)
3656 * No kind of locking is needed in here, because ->can_attach() will
3657 * check this value once in the beginning of the process, and then carry
3658 * on with stale data. This means that changes to this value will only
3659 * affect task migrations starting after the change.
3661 memcg->move_charge_at_immigrate = val;
3665 static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css,
3666 struct cftype *cft, u64 val)
3674 #define LRU_ALL_FILE (BIT(LRU_INACTIVE_FILE) | BIT(LRU_ACTIVE_FILE))
3675 #define LRU_ALL_ANON (BIT(LRU_INACTIVE_ANON) | BIT(LRU_ACTIVE_ANON))
3676 #define LRU_ALL ((1 << NR_LRU_LISTS) - 1)
3678 static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg,
3679 int nid, unsigned int lru_mask)
3681 struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid));
3682 unsigned long nr = 0;
3685 VM_BUG_ON((unsigned)nid >= nr_node_ids);
3688 if (!(BIT(lru) & lru_mask))
3690 nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru);
3695 static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg,
3696 unsigned int lru_mask)
3698 unsigned long nr = 0;
3702 if (!(BIT(lru) & lru_mask))
3704 nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru);
3709 static int memcg_numa_stat_show(struct seq_file *m, void *v)
3713 unsigned int lru_mask;
3716 static const struct numa_stat stats[] = {
3717 { "total", LRU_ALL },
3718 { "file", LRU_ALL_FILE },
3719 { "anon", LRU_ALL_ANON },
3720 { "unevictable", BIT(LRU_UNEVICTABLE) },
3722 const struct numa_stat *stat;
3725 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
3727 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3728 nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask);
3729 seq_printf(m, "%s=%lu", stat->name, nr);
3730 for_each_node_state(nid, N_MEMORY) {
3731 nr = mem_cgroup_node_nr_lru_pages(memcg, nid,
3733 seq_printf(m, " N%d=%lu", nid, nr);
3738 for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) {
3739 struct mem_cgroup *iter;
3742 for_each_mem_cgroup_tree(iter, memcg)
3743 nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask);
3744 seq_printf(m, "hierarchical_%s=%lu", stat->name, nr);
3745 for_each_node_state(nid, N_MEMORY) {
3747 for_each_mem_cgroup_tree(iter, memcg)
3748 nr += mem_cgroup_node_nr_lru_pages(
3749 iter, nid, stat->lru_mask);
3750 seq_printf(m, " N%d=%lu", nid, nr);
3757 #endif /* CONFIG_NUMA */
3759 static const unsigned int memcg1_stats[] = {
3770 static const char *const memcg1_stat_names[] = {
3781 /* Universal VM events cgroup1 shows, original sort order */
3782 static const unsigned int memcg1_events[] = {
3789 static int memcg_stat_show(struct seq_file *m, void *v)
3791 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
3792 unsigned long memory, memsw;
3793 struct mem_cgroup *mi;
3796 BUILD_BUG_ON(ARRAY_SIZE(memcg1_stat_names) != ARRAY_SIZE(memcg1_stats));
3798 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
3799 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
3801 seq_printf(m, "%s %lu\n", memcg1_stat_names[i],
3802 memcg_page_state_local(memcg, memcg1_stats[i]) *
3806 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
3807 seq_printf(m, "%s %lu\n", vm_event_name(memcg1_events[i]),
3808 memcg_events_local(memcg, memcg1_events[i]));
3810 for (i = 0; i < NR_LRU_LISTS; i++)
3811 seq_printf(m, "%s %lu\n", lru_list_name(i),
3812 memcg_page_state_local(memcg, NR_LRU_BASE + i) *
3815 /* Hierarchical information */
3816 memory = memsw = PAGE_COUNTER_MAX;
3817 for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) {
3818 memory = min(memory, mi->memory.max);
3819 memsw = min(memsw, mi->memsw.max);
3821 seq_printf(m, "hierarchical_memory_limit %llu\n",
3822 (u64)memory * PAGE_SIZE);
3823 if (do_memsw_account())
3824 seq_printf(m, "hierarchical_memsw_limit %llu\n",
3825 (u64)memsw * PAGE_SIZE);
3827 for (i = 0; i < ARRAY_SIZE(memcg1_stats); i++) {
3828 if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
3830 seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
3831 (u64)memcg_page_state(memcg, memcg1_stats[i]) *
3835 for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
3836 seq_printf(m, "total_%s %llu\n",
3837 vm_event_name(memcg1_events[i]),
3838 (u64)memcg_events(memcg, memcg1_events[i]));
3840 for (i = 0; i < NR_LRU_LISTS; i++)
3841 seq_printf(m, "total_%s %llu\n", lru_list_name(i),
3842 (u64)memcg_page_state(memcg, NR_LRU_BASE + i) *
3845 #ifdef CONFIG_DEBUG_VM
3848 struct mem_cgroup_per_node *mz;
3849 struct zone_reclaim_stat *rstat;
3850 unsigned long recent_rotated[2] = {0, 0};
3851 unsigned long recent_scanned[2] = {0, 0};
3853 for_each_online_pgdat(pgdat) {
3854 mz = mem_cgroup_nodeinfo(memcg, pgdat->node_id);
3855 rstat = &mz->lruvec.reclaim_stat;
3857 recent_rotated[0] += rstat->recent_rotated[0];
3858 recent_rotated[1] += rstat->recent_rotated[1];
3859 recent_scanned[0] += rstat->recent_scanned[0];
3860 recent_scanned[1] += rstat->recent_scanned[1];
3862 seq_printf(m, "recent_rotated_anon %lu\n", recent_rotated[0]);
3863 seq_printf(m, "recent_rotated_file %lu\n", recent_rotated[1]);
3864 seq_printf(m, "recent_scanned_anon %lu\n", recent_scanned[0]);
3865 seq_printf(m, "recent_scanned_file %lu\n", recent_scanned[1]);
3872 static u64 mem_cgroup_swappiness_read(struct cgroup_subsys_state *css,
3875 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3877 return mem_cgroup_swappiness(memcg);
3880 static int mem_cgroup_swappiness_write(struct cgroup_subsys_state *css,
3881 struct cftype *cft, u64 val)
3883 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
3889 memcg->swappiness = val;
3891 vm_swappiness = val;
3896 static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
3898 struct mem_cgroup_threshold_ary *t;
3899 unsigned long usage;
3904 t = rcu_dereference(memcg->thresholds.primary);
3906 t = rcu_dereference(memcg->memsw_thresholds.primary);
3911 usage = mem_cgroup_usage(memcg, swap);
3914 * current_threshold points to threshold just below or equal to usage.
3915 * If it's not true, a threshold was crossed after last
3916 * call of __mem_cgroup_threshold().
3918 i = t->current_threshold;
3921 * Iterate backward over array of thresholds starting from
3922 * current_threshold and check if a threshold is crossed.
3923 * If none of thresholds below usage is crossed, we read
3924 * only one element of the array here.
3926 for (; i >= 0 && unlikely(t->entries[i].threshold > usage); i--)
3927 eventfd_signal(t->entries[i].eventfd, 1);
3929 /* i = current_threshold + 1 */
3933 * Iterate forward over array of thresholds starting from
3934 * current_threshold+1 and check if a threshold is crossed.
3935 * If none of thresholds above usage is crossed, we read
3936 * only one element of the array here.
3938 for (; i < t->size && unlikely(t->entries[i].threshold <= usage); i++)
3939 eventfd_signal(t->entries[i].eventfd, 1);
3941 /* Update current_threshold */
3942 t->current_threshold = i - 1;
3947 static void mem_cgroup_threshold(struct mem_cgroup *memcg)
3950 __mem_cgroup_threshold(memcg, false);
3951 if (do_memsw_account())
3952 __mem_cgroup_threshold(memcg, true);
3954 memcg = parent_mem_cgroup(memcg);
3958 static int compare_thresholds(const void *a, const void *b)
3960 const struct mem_cgroup_threshold *_a = a;
3961 const struct mem_cgroup_threshold *_b = b;
3963 if (_a->threshold > _b->threshold)
3966 if (_a->threshold < _b->threshold)
3972 static int mem_cgroup_oom_notify_cb(struct mem_cgroup *memcg)
3974 struct mem_cgroup_eventfd_list *ev;
3976 spin_lock(&memcg_oom_lock);
3978 list_for_each_entry(ev, &memcg->oom_notify, list)
3979 eventfd_signal(ev->eventfd, 1);
3981 spin_unlock(&memcg_oom_lock);
3985 static void mem_cgroup_oom_notify(struct mem_cgroup *memcg)
3987 struct mem_cgroup *iter;
3989 for_each_mem_cgroup_tree(iter, memcg)
3990 mem_cgroup_oom_notify_cb(iter);
3993 static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
3994 struct eventfd_ctx *eventfd, const char *args, enum res_type type)
3996 struct mem_cgroup_thresholds *thresholds;
3997 struct mem_cgroup_threshold_ary *new;
3998 unsigned long threshold;
3999 unsigned long usage;
4002 ret = page_counter_memparse(args, "-1", &threshold);
4006 mutex_lock(&memcg->thresholds_lock);
4009 thresholds = &memcg->thresholds;
4010 usage = mem_cgroup_usage(memcg, false);
4011 } else if (type == _MEMSWAP) {
4012 thresholds = &memcg->memsw_thresholds;
4013 usage = mem_cgroup_usage(memcg, true);
4017 /* Check if a threshold crossed before adding a new one */
4018 if (thresholds->primary)
4019 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4021 size = thresholds->primary ? thresholds->primary->size + 1 : 1;
4023 /* Allocate memory for new array of thresholds */
4024 new = kmalloc(struct_size(new, entries, size), GFP_KERNEL);
4031 /* Copy thresholds (if any) to new array */
4032 if (thresholds->primary) {
4033 memcpy(new->entries, thresholds->primary->entries, (size - 1) *
4034 sizeof(struct mem_cgroup_threshold));
4037 /* Add new threshold */
4038 new->entries[size - 1].eventfd = eventfd;
4039 new->entries[size - 1].threshold = threshold;
4041 /* Sort thresholds. Registering of new threshold isn't time-critical */
4042 sort(new->entries, size, sizeof(struct mem_cgroup_threshold),
4043 compare_thresholds, NULL);
4045 /* Find current threshold */
4046 new->current_threshold = -1;
4047 for (i = 0; i < size; i++) {
4048 if (new->entries[i].threshold <= usage) {
4050 * new->current_threshold will not be used until
4051 * rcu_assign_pointer(), so it's safe to increment
4054 ++new->current_threshold;
4059 /* Free old spare buffer and save old primary buffer as spare */
4060 kfree(thresholds->spare);
4061 thresholds->spare = thresholds->primary;
4063 rcu_assign_pointer(thresholds->primary, new);
4065 /* To be sure that nobody uses thresholds */
4069 mutex_unlock(&memcg->thresholds_lock);
4074 static int mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
4075 struct eventfd_ctx *eventfd, const char *args)
4077 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEM);
4080 static int memsw_cgroup_usage_register_event(struct mem_cgroup *memcg,
4081 struct eventfd_ctx *eventfd, const char *args)
4083 return __mem_cgroup_usage_register_event(memcg, eventfd, args, _MEMSWAP);
4086 static void __mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4087 struct eventfd_ctx *eventfd, enum res_type type)
4089 struct mem_cgroup_thresholds *thresholds;
4090 struct mem_cgroup_threshold_ary *new;
4091 unsigned long usage;
4092 int i, j, size, entries;
4094 mutex_lock(&memcg->thresholds_lock);
4097 thresholds = &memcg->thresholds;
4098 usage = mem_cgroup_usage(memcg, false);
4099 } else if (type == _MEMSWAP) {
4100 thresholds = &memcg->memsw_thresholds;
4101 usage = mem_cgroup_usage(memcg, true);
4105 if (!thresholds->primary)
4108 /* Check if a threshold crossed before removing */
4109 __mem_cgroup_threshold(memcg, type == _MEMSWAP);
4111 /* Calculate new number of threshold */
4113 for (i = 0; i < thresholds->primary->size; i++) {
4114 if (thresholds->primary->entries[i].eventfd != eventfd)
4120 new = thresholds->spare;
4122 /* If no items related to eventfd have been cleared, nothing to do */
4126 /* Set thresholds array to NULL if we don't have thresholds */
4135 /* Copy thresholds and find current threshold */
4136 new->current_threshold = -1;
4137 for (i = 0, j = 0; i < thresholds->primary->size; i++) {
4138 if (thresholds->primary->entries[i].eventfd == eventfd)
4141 new->entries[j] = thresholds->primary->entries[i];
4142 if (new->entries[j].threshold <= usage) {
4144 * new->current_threshold will not be used
4145 * until rcu_assign_pointer(), so it's safe to increment
4148 ++new->current_threshold;
4154 /* Swap primary and spare array */
4155 thresholds->spare = thresholds->primary;
4157 rcu_assign_pointer(thresholds->primary, new);
4159 /* To be sure that nobody uses thresholds */
4162 /* If all events are unregistered, free the spare array */
4164 kfree(thresholds->spare);
4165 thresholds->spare = NULL;
4168 mutex_unlock(&memcg->thresholds_lock);
4171 static void mem_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4172 struct eventfd_ctx *eventfd)
4174 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEM);
4177 static void memsw_cgroup_usage_unregister_event(struct mem_cgroup *memcg,
4178 struct eventfd_ctx *eventfd)
4180 return __mem_cgroup_usage_unregister_event(memcg, eventfd, _MEMSWAP);
4183 static int mem_cgroup_oom_register_event(struct mem_cgroup *memcg,
4184 struct eventfd_ctx *eventfd, const char *args)
4186 struct mem_cgroup_eventfd_list *event;
4188 event = kmalloc(sizeof(*event), GFP_KERNEL);
4192 spin_lock(&memcg_oom_lock);
4194 event->eventfd = eventfd;
4195 list_add(&event->list, &memcg->oom_notify);
4197 /* already in OOM ? */
4198 if (memcg->under_oom)
4199 eventfd_signal(eventfd, 1);
4200 spin_unlock(&memcg_oom_lock);
4205 static void mem_cgroup_oom_unregister_event(struct mem_cgroup *memcg,
4206 struct eventfd_ctx *eventfd)
4208 struct mem_cgroup_eventfd_list *ev, *tmp;
4210 spin_lock(&memcg_oom_lock);
4212 list_for_each_entry_safe(ev, tmp, &memcg->oom_notify, list) {
4213 if (ev->eventfd == eventfd) {
4214 list_del(&ev->list);
4219 spin_unlock(&memcg_oom_lock);
4222 static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v)
4224 struct mem_cgroup *memcg = mem_cgroup_from_seq(sf);
4226 seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable);
4227 seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom);
4228 seq_printf(sf, "oom_kill %lu\n",
4229 atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL]));
4233 static int mem_cgroup_oom_control_write(struct cgroup_subsys_state *css,
4234 struct cftype *cft, u64 val)
4236 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4238 /* cannot set to root cgroup and only 0 and 1 are allowed */
4239 if (!css->parent || !((val == 0) || (val == 1)))
4242 memcg->oom_kill_disable = val;
4244 memcg_oom_recover(memcg);
4249 #ifdef CONFIG_CGROUP_WRITEBACK
4251 #include <trace/events/writeback.h>
4253 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4255 return wb_domain_init(&memcg->cgwb_domain, gfp);
4258 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4260 wb_domain_exit(&memcg->cgwb_domain);
4263 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4265 wb_domain_size_changed(&memcg->cgwb_domain);
4268 struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
4270 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4272 if (!memcg->css.parent)
4275 return &memcg->cgwb_domain;
4279 * idx can be of type enum memcg_stat_item or node_stat_item.
4280 * Keep in sync with memcg_exact_page().
4282 static unsigned long memcg_exact_page_state(struct mem_cgroup *memcg, int idx)
4284 long x = atomic_long_read(&memcg->vmstats[idx]);
4287 for_each_online_cpu(cpu)
4288 x += per_cpu_ptr(memcg->vmstats_percpu, cpu)->stat[idx];
4295 * mem_cgroup_wb_stats - retrieve writeback related stats from its memcg
4296 * @wb: bdi_writeback in question
4297 * @pfilepages: out parameter for number of file pages
4298 * @pheadroom: out parameter for number of allocatable pages according to memcg
4299 * @pdirty: out parameter for number of dirty pages
4300 * @pwriteback: out parameter for number of pages under writeback
4302 * Determine the numbers of file, headroom, dirty, and writeback pages in
4303 * @wb's memcg. File, dirty and writeback are self-explanatory. Headroom
4304 * is a bit more involved.
4306 * A memcg's headroom is "min(max, high) - used". In the hierarchy, the
4307 * headroom is calculated as the lowest headroom of itself and the
4308 * ancestors. Note that this doesn't consider the actual amount of
4309 * available memory in the system. The caller should further cap
4310 * *@pheadroom accordingly.
4312 void mem_cgroup_wb_stats(struct bdi_writeback *wb, unsigned long *pfilepages,
4313 unsigned long *pheadroom, unsigned long *pdirty,
4314 unsigned long *pwriteback)
4316 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4317 struct mem_cgroup *parent;
4319 *pdirty = memcg_exact_page_state(memcg, NR_FILE_DIRTY);
4321 /* this should eventually include NR_UNSTABLE_NFS */
4322 *pwriteback = memcg_exact_page_state(memcg, NR_WRITEBACK);
4323 *pfilepages = memcg_exact_page_state(memcg, NR_INACTIVE_FILE) +
4324 memcg_exact_page_state(memcg, NR_ACTIVE_FILE);
4325 *pheadroom = PAGE_COUNTER_MAX;
4327 while ((parent = parent_mem_cgroup(memcg))) {
4328 unsigned long ceiling = min(memcg->memory.max,
4329 READ_ONCE(memcg->high));
4330 unsigned long used = page_counter_read(&memcg->memory);
4332 *pheadroom = min(*pheadroom, ceiling - min(ceiling, used));
4338 * Foreign dirty flushing
4340 * There's an inherent mismatch between memcg and writeback. The former
4341 * trackes ownership per-page while the latter per-inode. This was a
4342 * deliberate design decision because honoring per-page ownership in the
4343 * writeback path is complicated, may lead to higher CPU and IO overheads
4344 * and deemed unnecessary given that write-sharing an inode across
4345 * different cgroups isn't a common use-case.
4347 * Combined with inode majority-writer ownership switching, this works well
4348 * enough in most cases but there are some pathological cases. For
4349 * example, let's say there are two cgroups A and B which keep writing to
4350 * different but confined parts of the same inode. B owns the inode and
4351 * A's memory is limited far below B's. A's dirty ratio can rise enough to
4352 * trigger balance_dirty_pages() sleeps but B's can be low enough to avoid
4353 * triggering background writeback. A will be slowed down without a way to
4354 * make writeback of the dirty pages happen.
4356 * Conditions like the above can lead to a cgroup getting repatedly and
4357 * severely throttled after making some progress after each
4358 * dirty_expire_interval while the underyling IO device is almost
4361 * Solving this problem completely requires matching the ownership tracking
4362 * granularities between memcg and writeback in either direction. However,
4363 * the more egregious behaviors can be avoided by simply remembering the
4364 * most recent foreign dirtying events and initiating remote flushes on
4365 * them when local writeback isn't enough to keep the memory clean enough.
4367 * The following two functions implement such mechanism. When a foreign
4368 * page - a page whose memcg and writeback ownerships don't match - is
4369 * dirtied, mem_cgroup_track_foreign_dirty() records the inode owning
4370 * bdi_writeback on the page owning memcg. When balance_dirty_pages()
4371 * decides that the memcg needs to sleep due to high dirty ratio, it calls
4372 * mem_cgroup_flush_foreign() which queues writeback on the recorded
4373 * foreign bdi_writebacks which haven't expired. Both the numbers of
4374 * recorded bdi_writebacks and concurrent in-flight foreign writebacks are
4375 * limited to MEMCG_CGWB_FRN_CNT.
4377 * The mechanism only remembers IDs and doesn't hold any object references.
4378 * As being wrong occasionally doesn't matter, updates and accesses to the
4379 * records are lockless and racy.
4381 void mem_cgroup_track_foreign_dirty_slowpath(struct page *page,
4382 struct bdi_writeback *wb)
4384 struct mem_cgroup *memcg = page->mem_cgroup;
4385 struct memcg_cgwb_frn *frn;
4386 u64 now = get_jiffies_64();
4387 u64 oldest_at = now;
4391 trace_track_foreign_dirty(page, wb);
4394 * Pick the slot to use. If there is already a slot for @wb, keep
4395 * using it. If not replace the oldest one which isn't being
4398 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4399 frn = &memcg->cgwb_frn[i];
4400 if (frn->bdi_id == wb->bdi->id &&
4401 frn->memcg_id == wb->memcg_css->id)
4403 if (time_before64(frn->at, oldest_at) &&
4404 atomic_read(&frn->done.cnt) == 1) {
4406 oldest_at = frn->at;
4410 if (i < MEMCG_CGWB_FRN_CNT) {
4412 * Re-using an existing one. Update timestamp lazily to
4413 * avoid making the cacheline hot. We want them to be
4414 * reasonably up-to-date and significantly shorter than
4415 * dirty_expire_interval as that's what expires the record.
4416 * Use the shorter of 1s and dirty_expire_interval / 8.
4418 unsigned long update_intv =
4419 min_t(unsigned long, HZ,
4420 msecs_to_jiffies(dirty_expire_interval * 10) / 8);
4422 if (time_before64(frn->at, now - update_intv))
4424 } else if (oldest >= 0) {
4425 /* replace the oldest free one */
4426 frn = &memcg->cgwb_frn[oldest];
4427 frn->bdi_id = wb->bdi->id;
4428 frn->memcg_id = wb->memcg_css->id;
4433 /* issue foreign writeback flushes for recorded foreign dirtying events */
4434 void mem_cgroup_flush_foreign(struct bdi_writeback *wb)
4436 struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
4437 unsigned long intv = msecs_to_jiffies(dirty_expire_interval * 10);
4438 u64 now = jiffies_64;
4441 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++) {
4442 struct memcg_cgwb_frn *frn = &memcg->cgwb_frn[i];
4445 * If the record is older than dirty_expire_interval,
4446 * writeback on it has already started. No need to kick it
4447 * off again. Also, don't start a new one if there's
4448 * already one in flight.
4450 if (time_after64(frn->at, now - intv) &&
4451 atomic_read(&frn->done.cnt) == 1) {
4453 trace_flush_foreign(wb, frn->bdi_id, frn->memcg_id);
4454 cgroup_writeback_by_id(frn->bdi_id, frn->memcg_id, 0,
4455 WB_REASON_FOREIGN_FLUSH,
4461 #else /* CONFIG_CGROUP_WRITEBACK */
4463 static int memcg_wb_domain_init(struct mem_cgroup *memcg, gfp_t gfp)
4468 static void memcg_wb_domain_exit(struct mem_cgroup *memcg)
4472 static void memcg_wb_domain_size_changed(struct mem_cgroup *memcg)
4476 #endif /* CONFIG_CGROUP_WRITEBACK */
4479 * DO NOT USE IN NEW FILES.
4481 * "cgroup.event_control" implementation.
4483 * This is way over-engineered. It tries to support fully configurable
4484 * events for each user. Such level of flexibility is completely
4485 * unnecessary especially in the light of the planned unified hierarchy.
4487 * Please deprecate this and replace with something simpler if at all
4492 * Unregister event and free resources.
4494 * Gets called from workqueue.
4496 static void memcg_event_remove(struct work_struct *work)
4498 struct mem_cgroup_event *event =
4499 container_of(work, struct mem_cgroup_event, remove);
4500 struct mem_cgroup *memcg = event->memcg;
4502 remove_wait_queue(event->wqh, &event->wait);
4504 event->unregister_event(memcg, event->eventfd);
4506 /* Notify userspace the event is going away. */
4507 eventfd_signal(event->eventfd, 1);
4509 eventfd_ctx_put(event->eventfd);
4511 css_put(&memcg->css);
4515 * Gets called on EPOLLHUP on eventfd when user closes it.
4517 * Called with wqh->lock held and interrupts disabled.
4519 static int memcg_event_wake(wait_queue_entry_t *wait, unsigned mode,
4520 int sync, void *key)
4522 struct mem_cgroup_event *event =
4523 container_of(wait, struct mem_cgroup_event, wait);
4524 struct mem_cgroup *memcg = event->memcg;
4525 __poll_t flags = key_to_poll(key);
4527 if (flags & EPOLLHUP) {
4529 * If the event has been detached at cgroup removal, we
4530 * can simply return knowing the other side will cleanup
4533 * We can't race against event freeing since the other
4534 * side will require wqh->lock via remove_wait_queue(),
4537 spin_lock(&memcg->event_list_lock);
4538 if (!list_empty(&event->list)) {
4539 list_del_init(&event->list);
4541 * We are in atomic context, but cgroup_event_remove()
4542 * may sleep, so we have to call it in workqueue.
4544 schedule_work(&event->remove);
4546 spin_unlock(&memcg->event_list_lock);
4552 static void memcg_event_ptable_queue_proc(struct file *file,
4553 wait_queue_head_t *wqh, poll_table *pt)
4555 struct mem_cgroup_event *event =
4556 container_of(pt, struct mem_cgroup_event, pt);
4559 add_wait_queue(wqh, &event->wait);
4563 * DO NOT USE IN NEW FILES.
4565 * Parse input and register new cgroup event handler.
4567 * Input must be in format '<event_fd> <control_fd> <args>'.
4568 * Interpretation of args is defined by control file implementation.
4570 static ssize_t memcg_write_event_control(struct kernfs_open_file *of,
4571 char *buf, size_t nbytes, loff_t off)
4573 struct cgroup_subsys_state *css = of_css(of);
4574 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
4575 struct mem_cgroup_event *event;
4576 struct cgroup_subsys_state *cfile_css;
4577 unsigned int efd, cfd;
4584 buf = strstrip(buf);
4586 efd = simple_strtoul(buf, &endp, 10);
4591 cfd = simple_strtoul(buf, &endp, 10);
4592 if ((*endp != ' ') && (*endp != '\0'))
4596 event = kzalloc(sizeof(*event), GFP_KERNEL);
4600 event->memcg = memcg;
4601 INIT_LIST_HEAD(&event->list);
4602 init_poll_funcptr(&event->pt, memcg_event_ptable_queue_proc);
4603 init_waitqueue_func_entry(&event->wait, memcg_event_wake);
4604 INIT_WORK(&event->remove, memcg_event_remove);
4612 event->eventfd = eventfd_ctx_fileget(efile.file);
4613 if (IS_ERR(event->eventfd)) {
4614 ret = PTR_ERR(event->eventfd);
4621 goto out_put_eventfd;
4624 /* the process need read permission on control file */
4625 /* AV: shouldn't we check that it's been opened for read instead? */
4626 ret = inode_permission(file_inode(cfile.file), MAY_READ);
4631 * Determine the event callbacks and set them in @event. This used
4632 * to be done via struct cftype but cgroup core no longer knows
4633 * about these events. The following is crude but the whole thing
4634 * is for compatibility anyway.
4636 * DO NOT ADD NEW FILES.
4638 name = cfile.file->f_path.dentry->d_name.name;
4640 if (!strcmp(name, "memory.usage_in_bytes")) {
4641 event->register_event = mem_cgroup_usage_register_event;
4642 event->unregister_event = mem_cgroup_usage_unregister_event;
4643 } else if (!strcmp(name, "memory.oom_control")) {
4644 event->register_event = mem_cgroup_oom_register_event;
4645 event->unregister_event = mem_cgroup_oom_unregister_event;
4646 } else if (!strcmp(name, "memory.pressure_level")) {
4647 event->register_event = vmpressure_register_event;
4648 event->unregister_event = vmpressure_unregister_event;
4649 } else if (!strcmp(name, "memory.memsw.usage_in_bytes")) {
4650 event->register_event = memsw_cgroup_usage_register_event;
4651 event->unregister_event = memsw_cgroup_usage_unregister_event;
4658 * Verify @cfile should belong to @css. Also, remaining events are
4659 * automatically removed on cgroup destruction but the removal is
4660 * asynchronous, so take an extra ref on @css.
4662 cfile_css = css_tryget_online_from_dir(cfile.file->f_path.dentry->d_parent,
4663 &memory_cgrp_subsys);
4665 if (IS_ERR(cfile_css))
4667 if (cfile_css != css) {
4672 ret = event->register_event(memcg, event->eventfd, buf);
4676 vfs_poll(efile.file, &event->pt);
4678 spin_lock(&memcg->event_list_lock);
4679 list_add(&event->list, &memcg->event_list);
4680 spin_unlock(&memcg->event_list_lock);
4692 eventfd_ctx_put(event->eventfd);
4701 static struct cftype mem_cgroup_legacy_files[] = {
4703 .name = "usage_in_bytes",
4704 .private = MEMFILE_PRIVATE(_MEM, RES_USAGE),
4705 .read_u64 = mem_cgroup_read_u64,
4708 .name = "max_usage_in_bytes",
4709 .private = MEMFILE_PRIVATE(_MEM, RES_MAX_USAGE),
4710 .write = mem_cgroup_reset,
4711 .read_u64 = mem_cgroup_read_u64,
4714 .name = "limit_in_bytes",
4715 .private = MEMFILE_PRIVATE(_MEM, RES_LIMIT),
4716 .write = mem_cgroup_write,
4717 .read_u64 = mem_cgroup_read_u64,
4720 .name = "soft_limit_in_bytes",
4721 .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
4722 .write = mem_cgroup_write,
4723 .read_u64 = mem_cgroup_read_u64,
4727 .private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
4728 .write = mem_cgroup_reset,
4729 .read_u64 = mem_cgroup_read_u64,
4733 .seq_show = memcg_stat_show,
4736 .name = "force_empty",
4737 .write = mem_cgroup_force_empty_write,
4740 .name = "use_hierarchy",
4741 .write_u64 = mem_cgroup_hierarchy_write,
4742 .read_u64 = mem_cgroup_hierarchy_read,
4745 .name = "cgroup.event_control", /* XXX: for compat */
4746 .write = memcg_write_event_control,
4747 .flags = CFTYPE_NO_PREFIX | CFTYPE_WORLD_WRITABLE,
4750 .name = "swappiness",
4751 .read_u64 = mem_cgroup_swappiness_read,
4752 .write_u64 = mem_cgroup_swappiness_write,
4755 .name = "move_charge_at_immigrate",
4756 .read_u64 = mem_cgroup_move_charge_read,
4757 .write_u64 = mem_cgroup_move_charge_write,
4760 .name = "oom_control",
4761 .seq_show = mem_cgroup_oom_control_read,
4762 .write_u64 = mem_cgroup_oom_control_write,
4763 .private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
4766 .name = "pressure_level",
4770 .name = "numa_stat",
4771 .seq_show = memcg_numa_stat_show,
4775 .name = "kmem.limit_in_bytes",
4776 .private = MEMFILE_PRIVATE(_KMEM, RES_LIMIT),
4777 .write = mem_cgroup_write,
4778 .read_u64 = mem_cgroup_read_u64,
4781 .name = "kmem.usage_in_bytes",
4782 .private = MEMFILE_PRIVATE(_KMEM, RES_USAGE),
4783 .read_u64 = mem_cgroup_read_u64,
4786 .name = "kmem.failcnt",
4787 .private = MEMFILE_PRIVATE(_KMEM, RES_FAILCNT),
4788 .write = mem_cgroup_reset,
4789 .read_u64 = mem_cgroup_read_u64,
4792 .name = "kmem.max_usage_in_bytes",
4793 .private = MEMFILE_PRIVATE(_KMEM, RES_MAX_USAGE),
4794 .write = mem_cgroup_reset,
4795 .read_u64 = mem_cgroup_read_u64,
4797 #if defined(CONFIG_MEMCG_KMEM) && \
4798 (defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG))
4800 .name = "kmem.slabinfo",
4801 .seq_start = memcg_slab_start,
4802 .seq_next = memcg_slab_next,
4803 .seq_stop = memcg_slab_stop,
4804 .seq_show = memcg_slab_show,
4808 .name = "kmem.tcp.limit_in_bytes",
4809 .private = MEMFILE_PRIVATE(_TCP, RES_LIMIT),
4810 .write = mem_cgroup_write,
4811 .read_u64 = mem_cgroup_read_u64,
4814 .name = "kmem.tcp.usage_in_bytes",
4815 .private = MEMFILE_PRIVATE(_TCP, RES_USAGE),
4816 .read_u64 = mem_cgroup_read_u64,
4819 .name = "kmem.tcp.failcnt",
4820 .private = MEMFILE_PRIVATE(_TCP, RES_FAILCNT),
4821 .write = mem_cgroup_reset,
4822 .read_u64 = mem_cgroup_read_u64,
4825 .name = "kmem.tcp.max_usage_in_bytes",
4826 .private = MEMFILE_PRIVATE(_TCP, RES_MAX_USAGE),
4827 .write = mem_cgroup_reset,
4828 .read_u64 = mem_cgroup_read_u64,
4830 { }, /* terminate */
4834 * Private memory cgroup IDR
4836 * Swap-out records and page cache shadow entries need to store memcg
4837 * references in constrained space, so we maintain an ID space that is
4838 * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
4839 * memory-controlled cgroups to 64k.
4841 * However, there usually are many references to the oflline CSS after
4842 * the cgroup has been destroyed, such as page cache or reclaimable
4843 * slab objects, that don't need to hang on to the ID. We want to keep
4844 * those dead CSS from occupying IDs, or we might quickly exhaust the
4845 * relatively small ID space and prevent the creation of new cgroups
4846 * even when there are much fewer than 64k cgroups - possibly none.
4848 * Maintain a private 16-bit ID space for memcg, and allow the ID to
4849 * be freed and recycled when it's no longer needed, which is usually
4850 * when the CSS is offlined.
4852 * The only exception to that are records of swapped out tmpfs/shmem
4853 * pages that need to be attributed to live ancestors on swapin. But
4854 * those references are manageable from userspace.
4857 static DEFINE_IDR(mem_cgroup_idr);
4859 static void mem_cgroup_id_remove(struct mem_cgroup *memcg)
4861 if (memcg->id.id > 0) {
4862 idr_remove(&mem_cgroup_idr, memcg->id.id);
4867 static void __maybe_unused mem_cgroup_id_get_many(struct mem_cgroup *memcg,
4870 refcount_add(n, &memcg->id.ref);
4873 static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
4875 if (refcount_sub_and_test(n, &memcg->id.ref)) {
4876 mem_cgroup_id_remove(memcg);
4878 /* Memcg ID pins CSS */
4879 css_put(&memcg->css);
4883 static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
4885 mem_cgroup_id_put_many(memcg, 1);
4889 * mem_cgroup_from_id - look up a memcg from a memcg id
4890 * @id: the memcg id to look up
4892 * Caller must hold rcu_read_lock().
4894 struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
4896 WARN_ON_ONCE(!rcu_read_lock_held());
4897 return idr_find(&mem_cgroup_idr, id);
4900 static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4902 struct mem_cgroup_per_node *pn;
4905 * This routine is called against possible nodes.
4906 * But it's BUG to call kmalloc() against offline node.
4908 * TODO: this routine can waste much memory for nodes which will
4909 * never be onlined. It's better to use memory hotplug callback
4912 if (!node_state(node, N_NORMAL_MEMORY))
4914 pn = kzalloc_node(sizeof(*pn), GFP_KERNEL, tmp);
4918 pn->lruvec_stat_local = alloc_percpu(struct lruvec_stat);
4919 if (!pn->lruvec_stat_local) {
4924 pn->lruvec_stat_cpu = alloc_percpu(struct lruvec_stat);
4925 if (!pn->lruvec_stat_cpu) {
4926 free_percpu(pn->lruvec_stat_local);
4931 lruvec_init(&pn->lruvec);
4932 pn->usage_in_excess = 0;
4933 pn->on_tree = false;
4936 memcg->nodeinfo[node] = pn;
4940 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
4942 struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
4947 free_percpu(pn->lruvec_stat_cpu);
4948 free_percpu(pn->lruvec_stat_local);
4952 static void __mem_cgroup_free(struct mem_cgroup *memcg)
4957 free_mem_cgroup_per_node_info(memcg, node);
4958 free_percpu(memcg->vmstats_percpu);
4959 free_percpu(memcg->vmstats_local);
4963 static void mem_cgroup_free(struct mem_cgroup *memcg)
4965 memcg_wb_domain_exit(memcg);
4967 * Flush percpu vmstats and vmevents to guarantee the value correctness
4968 * on parent's and all ancestor levels.
4970 memcg_flush_percpu_vmstats(memcg);
4971 memcg_flush_percpu_vmevents(memcg);
4972 __mem_cgroup_free(memcg);
4975 static struct mem_cgroup *mem_cgroup_alloc(void)
4977 struct mem_cgroup *memcg;
4980 int __maybe_unused i;
4982 size = sizeof(struct mem_cgroup);
4983 size += nr_node_ids * sizeof(struct mem_cgroup_per_node *);
4985 memcg = kzalloc(size, GFP_KERNEL);
4989 memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
4990 1, MEM_CGROUP_ID_MAX,
4992 if (memcg->id.id < 0)
4995 memcg->vmstats_local = alloc_percpu(struct memcg_vmstats_percpu);
4996 if (!memcg->vmstats_local)
4999 memcg->vmstats_percpu = alloc_percpu(struct memcg_vmstats_percpu);
5000 if (!memcg->vmstats_percpu)
5004 if (alloc_mem_cgroup_per_node_info(memcg, node))
5007 if (memcg_wb_domain_init(memcg, GFP_KERNEL))
5010 INIT_WORK(&memcg->high_work, high_work_func);
5011 INIT_LIST_HEAD(&memcg->oom_notify);
5012 mutex_init(&memcg->thresholds_lock);
5013 spin_lock_init(&memcg->move_lock);
5014 vmpressure_init(&memcg->vmpressure);
5015 INIT_LIST_HEAD(&memcg->event_list);
5016 spin_lock_init(&memcg->event_list_lock);
5017 memcg->socket_pressure = jiffies;
5018 #ifdef CONFIG_MEMCG_KMEM
5019 memcg->kmemcg_id = -1;
5021 #ifdef CONFIG_CGROUP_WRITEBACK
5022 INIT_LIST_HEAD(&memcg->cgwb_list);
5023 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5024 memcg->cgwb_frn[i].done =
5025 __WB_COMPLETION_INIT(&memcg_cgwb_frn_waitq);
5027 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5028 spin_lock_init(&memcg->deferred_split_queue.split_queue_lock);
5029 INIT_LIST_HEAD(&memcg->deferred_split_queue.split_queue);
5030 memcg->deferred_split_queue.split_queue_len = 0;
5032 idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
5035 mem_cgroup_id_remove(memcg);
5036 __mem_cgroup_free(memcg);
5040 static struct cgroup_subsys_state * __ref
5041 mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
5043 struct mem_cgroup *parent = mem_cgroup_from_css(parent_css);
5044 struct mem_cgroup *memcg;
5045 long error = -ENOMEM;
5047 memcg = mem_cgroup_alloc();
5049 return ERR_PTR(error);
5051 WRITE_ONCE(memcg->high, PAGE_COUNTER_MAX);
5052 memcg->soft_limit = PAGE_COUNTER_MAX;
5054 memcg->swappiness = mem_cgroup_swappiness(parent);
5055 memcg->oom_kill_disable = parent->oom_kill_disable;
5057 if (parent && parent->use_hierarchy) {
5058 memcg->use_hierarchy = true;
5059 page_counter_init(&memcg->memory, &parent->memory);
5060 page_counter_init(&memcg->swap, &parent->swap);
5061 page_counter_init(&memcg->memsw, &parent->memsw);
5062 page_counter_init(&memcg->kmem, &parent->kmem);
5063 page_counter_init(&memcg->tcpmem, &parent->tcpmem);
5065 page_counter_init(&memcg->memory, NULL);
5066 page_counter_init(&memcg->swap, NULL);
5067 page_counter_init(&memcg->memsw, NULL);
5068 page_counter_init(&memcg->kmem, NULL);
5069 page_counter_init(&memcg->tcpmem, NULL);
5071 * Deeper hierachy with use_hierarchy == false doesn't make
5072 * much sense so let cgroup subsystem know about this
5073 * unfortunate state in our controller.
5075 if (parent != root_mem_cgroup)
5076 memory_cgrp_subsys.broken_hierarchy = true;
5079 /* The following stuff does not apply to the root */
5081 #ifdef CONFIG_MEMCG_KMEM
5082 INIT_LIST_HEAD(&memcg->kmem_caches);
5084 root_mem_cgroup = memcg;
5088 error = memcg_online_kmem(memcg);
5092 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5093 static_branch_inc(&memcg_sockets_enabled_key);
5097 mem_cgroup_id_remove(memcg);
5098 mem_cgroup_free(memcg);
5099 return ERR_PTR(-ENOMEM);
5102 static int mem_cgroup_css_online(struct cgroup_subsys_state *css)
5104 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5107 * A memcg must be visible for memcg_expand_shrinker_maps()
5108 * by the time the maps are allocated. So, we allocate maps
5109 * here, when for_each_mem_cgroup() can't skip it.
5111 if (memcg_alloc_shrinker_maps(memcg)) {
5112 mem_cgroup_id_remove(memcg);
5116 /* Online state pins memcg ID, memcg ID pins CSS */
5117 refcount_set(&memcg->id.ref, 1);
5122 static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
5124 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5125 struct mem_cgroup_event *event, *tmp;
5128 * Unregister events and notify userspace.
5129 * Notify userspace about cgroup removing only after rmdir of cgroup
5130 * directory to avoid race between userspace and kernelspace.
5132 spin_lock(&memcg->event_list_lock);
5133 list_for_each_entry_safe(event, tmp, &memcg->event_list, list) {
5134 list_del_init(&event->list);
5135 schedule_work(&event->remove);
5137 spin_unlock(&memcg->event_list_lock);
5139 page_counter_set_min(&memcg->memory, 0);
5140 page_counter_set_low(&memcg->memory, 0);
5142 memcg_offline_kmem(memcg);
5143 wb_memcg_offline(memcg);
5145 drain_all_stock(memcg);
5147 mem_cgroup_id_put(memcg);
5150 static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
5152 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5154 invalidate_reclaim_iterators(memcg);
5157 static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
5159 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5160 int __maybe_unused i;
5162 #ifdef CONFIG_CGROUP_WRITEBACK
5163 for (i = 0; i < MEMCG_CGWB_FRN_CNT; i++)
5164 wb_wait_for_completion(&memcg->cgwb_frn[i].done);
5166 if (cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_nosocket)
5167 static_branch_dec(&memcg_sockets_enabled_key);
5169 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg->tcpmem_active)
5170 static_branch_dec(&memcg_sockets_enabled_key);
5172 vmpressure_cleanup(&memcg->vmpressure);
5173 cancel_work_sync(&memcg->high_work);
5174 mem_cgroup_remove_from_trees(memcg);
5175 memcg_free_shrinker_maps(memcg);
5176 memcg_free_kmem(memcg);
5177 mem_cgroup_free(memcg);
5181 * mem_cgroup_css_reset - reset the states of a mem_cgroup
5182 * @css: the target css
5184 * Reset the states of the mem_cgroup associated with @css. This is
5185 * invoked when the userland requests disabling on the default hierarchy
5186 * but the memcg is pinned through dependency. The memcg should stop
5187 * applying policies and should revert to the vanilla state as it may be
5188 * made visible again.
5190 * The current implementation only resets the essential configurations.
5191 * This needs to be expanded to cover all the visible parts.
5193 static void mem_cgroup_css_reset(struct cgroup_subsys_state *css)
5195 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5197 page_counter_set_max(&memcg->memory, PAGE_COUNTER_MAX);
5198 page_counter_set_max(&memcg->swap, PAGE_COUNTER_MAX);
5199 page_counter_set_max(&memcg->memsw, PAGE_COUNTER_MAX);
5200 page_counter_set_max(&memcg->kmem, PAGE_COUNTER_MAX);
5201 page_counter_set_max(&memcg->tcpmem, PAGE_COUNTER_MAX);
5202 page_counter_set_min(&memcg->memory, 0);
5203 page_counter_set_low(&memcg->memory, 0);
5204 WRITE_ONCE(memcg->high, PAGE_COUNTER_MAX);
5205 memcg->soft_limit = PAGE_COUNTER_MAX;
5206 memcg_wb_domain_size_changed(memcg);
5210 /* Handlers for move charge at task migration. */
5211 static int mem_cgroup_do_precharge(unsigned long count)
5215 /* Try a single bulk charge without reclaim first, kswapd may wake */
5216 ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_DIRECT_RECLAIM, count);
5218 mc.precharge += count;
5222 /* Try charges one by one with reclaim, but do not retry */
5224 ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
5238 enum mc_target_type {
5245 static struct page *mc_handle_present_pte(struct vm_area_struct *vma,
5246 unsigned long addr, pte_t ptent)
5248 struct page *page = vm_normal_page(vma, addr, ptent);
5250 if (!page || !page_mapped(page))
5252 if (PageAnon(page)) {
5253 if (!(mc.flags & MOVE_ANON))
5256 if (!(mc.flags & MOVE_FILE))
5259 if (!get_page_unless_zero(page))
5265 #if defined(CONFIG_SWAP) || defined(CONFIG_DEVICE_PRIVATE)
5266 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5267 pte_t ptent, swp_entry_t *entry)
5269 struct page *page = NULL;
5270 swp_entry_t ent = pte_to_swp_entry(ptent);
5272 if (!(mc.flags & MOVE_ANON) || non_swap_entry(ent))
5276 * Handle MEMORY_DEVICE_PRIVATE which are ZONE_DEVICE page belonging to
5277 * a device and because they are not accessible by CPU they are store
5278 * as special swap entry in the CPU page table.
5280 if (is_device_private_entry(ent)) {
5281 page = device_private_entry_to_page(ent);
5283 * MEMORY_DEVICE_PRIVATE means ZONE_DEVICE page and which have
5284 * a refcount of 1 when free (unlike normal page)
5286 if (!page_ref_add_unless(page, 1, 1))
5292 * Because lookup_swap_cache() updates some statistics counter,
5293 * we call find_get_page() with swapper_space directly.
5295 page = find_get_page(swap_address_space(ent), swp_offset(ent));
5296 if (do_memsw_account())
5297 entry->val = ent.val;
5302 static struct page *mc_handle_swap_pte(struct vm_area_struct *vma,
5303 pte_t ptent, swp_entry_t *entry)
5309 static struct page *mc_handle_file_pte(struct vm_area_struct *vma,
5310 unsigned long addr, pte_t ptent, swp_entry_t *entry)
5312 struct page *page = NULL;
5313 struct address_space *mapping;
5316 if (!vma->vm_file) /* anonymous vma */
5318 if (!(mc.flags & MOVE_FILE))
5321 mapping = vma->vm_file->f_mapping;
5322 pgoff = linear_page_index(vma, addr);
5324 /* page is moved even if it's not RSS of this task(page-faulted). */
5326 /* shmem/tmpfs may report page out on swap: account for that too. */
5327 if (shmem_mapping(mapping)) {
5328 page = find_get_entry(mapping, pgoff);
5329 if (xa_is_value(page)) {
5330 swp_entry_t swp = radix_to_swp_entry(page);
5331 if (do_memsw_account())
5333 page = find_get_page(swap_address_space(swp),
5337 page = find_get_page(mapping, pgoff);
5339 page = find_get_page(mapping, pgoff);
5345 * mem_cgroup_move_account - move account of the page
5347 * @compound: charge the page as compound or small page
5348 * @from: mem_cgroup which the page is moved from.
5349 * @to: mem_cgroup which the page is moved to. @from != @to.
5351 * The caller must make sure the page is not on LRU (isolate_page() is useful.)
5353 * This function doesn't do "charge" to new cgroup and doesn't do "uncharge"
5356 static int mem_cgroup_move_account(struct page *page,
5358 struct mem_cgroup *from,
5359 struct mem_cgroup *to)
5361 struct lruvec *from_vec, *to_vec;
5362 struct pglist_data *pgdat;
5363 unsigned long flags;
5364 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
5368 VM_BUG_ON(from == to);
5369 VM_BUG_ON_PAGE(PageLRU(page), page);
5370 VM_BUG_ON(compound && !PageTransHuge(page));
5373 * Prevent mem_cgroup_migrate() from looking at
5374 * page->mem_cgroup of its source page while we change it.
5377 if (!trylock_page(page))
5381 if (page->mem_cgroup != from)
5384 anon = PageAnon(page);
5386 pgdat = page_pgdat(page);
5387 from_vec = mem_cgroup_lruvec(from, pgdat);
5388 to_vec = mem_cgroup_lruvec(to, pgdat);
5390 spin_lock_irqsave(&from->move_lock, flags);
5392 if (!anon && page_mapped(page)) {
5393 __mod_lruvec_state(from_vec, NR_FILE_MAPPED, -nr_pages);
5394 __mod_lruvec_state(to_vec, NR_FILE_MAPPED, nr_pages);
5398 * move_lock grabbed above and caller set from->moving_account, so
5399 * mod_memcg_page_state will serialize updates to PageDirty.
5400 * So mapping should be stable for dirty pages.
5402 if (!anon && PageDirty(page)) {
5403 struct address_space *mapping = page_mapping(page);
5405 if (mapping_cap_account_dirty(mapping)) {
5406 __mod_lruvec_state(from_vec, NR_FILE_DIRTY, -nr_pages);
5407 __mod_lruvec_state(to_vec, NR_FILE_DIRTY, nr_pages);
5411 if (PageWriteback(page)) {
5412 __mod_lruvec_state(from_vec, NR_WRITEBACK, -nr_pages);
5413 __mod_lruvec_state(to_vec, NR_WRITEBACK, nr_pages);
5417 * It is safe to change page->mem_cgroup here because the page
5418 * is referenced, charged, and isolated - we can't race with
5419 * uncharging, charging, migration, or LRU putback.
5422 /* caller should have done css_get */
5423 page->mem_cgroup = to;
5425 spin_unlock_irqrestore(&from->move_lock, flags);
5429 local_irq_disable();
5430 mem_cgroup_charge_statistics(to, page, compound, nr_pages);
5431 memcg_check_events(to, page);
5432 mem_cgroup_charge_statistics(from, page, compound, -nr_pages);
5433 memcg_check_events(from, page);
5442 * get_mctgt_type - get target type of moving charge
5443 * @vma: the vma the pte to be checked belongs
5444 * @addr: the address corresponding to the pte to be checked
5445 * @ptent: the pte to be checked
5446 * @target: the pointer the target page or swap ent will be stored(can be NULL)
5449 * 0(MC_TARGET_NONE): if the pte is not a target for move charge.
5450 * 1(MC_TARGET_PAGE): if the page corresponding to this pte is a target for
5451 * move charge. if @target is not NULL, the page is stored in target->page
5452 * with extra refcnt got(Callers should handle it).
5453 * 2(MC_TARGET_SWAP): if the swap entry corresponding to this pte is a
5454 * target for charge migration. if @target is not NULL, the entry is stored
5456 * 3(MC_TARGET_DEVICE): like MC_TARGET_PAGE but page is MEMORY_DEVICE_PRIVATE
5457 * (so ZONE_DEVICE page and thus not on the lru).
5458 * For now we such page is charge like a regular page would be as for all
5459 * intent and purposes it is just special memory taking the place of a
5462 * See Documentations/vm/hmm.txt and include/linux/hmm.h
5464 * Called with pte lock held.
5467 static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
5468 unsigned long addr, pte_t ptent, union mc_target *target)
5470 struct page *page = NULL;
5471 enum mc_target_type ret = MC_TARGET_NONE;
5472 swp_entry_t ent = { .val = 0 };
5474 if (pte_present(ptent))
5475 page = mc_handle_present_pte(vma, addr, ptent);
5476 else if (is_swap_pte(ptent))
5477 page = mc_handle_swap_pte(vma, ptent, &ent);
5478 else if (pte_none(ptent))
5479 page = mc_handle_file_pte(vma, addr, ptent, &ent);
5481 if (!page && !ent.val)
5485 * Do only loose check w/o serialization.
5486 * mem_cgroup_move_account() checks the page is valid or
5487 * not under LRU exclusion.
5489 if (page->mem_cgroup == mc.from) {
5490 ret = MC_TARGET_PAGE;
5491 if (is_device_private_page(page))
5492 ret = MC_TARGET_DEVICE;
5494 target->page = page;
5496 if (!ret || !target)
5500 * There is a swap entry and a page doesn't exist or isn't charged.
5501 * But we cannot move a tail-page in a THP.
5503 if (ent.val && !ret && (!page || !PageTransCompound(page)) &&
5504 mem_cgroup_id(mc.from) == lookup_swap_cgroup_id(ent)) {
5505 ret = MC_TARGET_SWAP;
5512 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
5514 * We don't consider PMD mapped swapping or file mapped pages because THP does
5515 * not support them for now.
5516 * Caller should make sure that pmd_trans_huge(pmd) is true.
5518 static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5519 unsigned long addr, pmd_t pmd, union mc_target *target)
5521 struct page *page = NULL;
5522 enum mc_target_type ret = MC_TARGET_NONE;
5524 if (unlikely(is_swap_pmd(pmd))) {
5525 VM_BUG_ON(thp_migration_supported() &&
5526 !is_pmd_migration_entry(pmd));
5529 page = pmd_page(pmd);
5530 VM_BUG_ON_PAGE(!page || !PageHead(page), page);
5531 if (!(mc.flags & MOVE_ANON))
5533 if (page->mem_cgroup == mc.from) {
5534 ret = MC_TARGET_PAGE;
5537 target->page = page;
5543 static inline enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
5544 unsigned long addr, pmd_t pmd, union mc_target *target)
5546 return MC_TARGET_NONE;
5550 static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd,
5551 unsigned long addr, unsigned long end,
5552 struct mm_walk *walk)
5554 struct vm_area_struct *vma = walk->vma;
5558 ptl = pmd_trans_huge_lock(pmd, vma);
5561 * Note their can not be MC_TARGET_DEVICE for now as we do not
5562 * support transparent huge page with MEMORY_DEVICE_PRIVATE but
5563 * this might change.
5565 if (get_mctgt_type_thp(vma, addr, *pmd, NULL) == MC_TARGET_PAGE)
5566 mc.precharge += HPAGE_PMD_NR;
5571 if (pmd_trans_unstable(pmd))
5573 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5574 for (; addr != end; pte++, addr += PAGE_SIZE)
5575 if (get_mctgt_type(vma, addr, *pte, NULL))
5576 mc.precharge++; /* increment precharge temporarily */
5577 pte_unmap_unlock(pte - 1, ptl);
5583 static const struct mm_walk_ops precharge_walk_ops = {
5584 .pmd_entry = mem_cgroup_count_precharge_pte_range,
5587 static unsigned long mem_cgroup_count_precharge(struct mm_struct *mm)
5589 unsigned long precharge;
5591 down_read(&mm->mmap_sem);
5592 walk_page_range(mm, 0, mm->highest_vm_end, &precharge_walk_ops, NULL);
5593 up_read(&mm->mmap_sem);
5595 precharge = mc.precharge;
5601 static int mem_cgroup_precharge_mc(struct mm_struct *mm)
5603 unsigned long precharge = mem_cgroup_count_precharge(mm);
5605 VM_BUG_ON(mc.moving_task);
5606 mc.moving_task = current;
5607 return mem_cgroup_do_precharge(precharge);
5610 /* cancels all extra charges on mc.from and mc.to, and wakes up all waiters. */
5611 static void __mem_cgroup_clear_mc(void)
5613 struct mem_cgroup *from = mc.from;
5614 struct mem_cgroup *to = mc.to;
5616 /* we must uncharge all the leftover precharges from mc.to */
5618 cancel_charge(mc.to, mc.precharge);
5622 * we didn't uncharge from mc.from at mem_cgroup_move_account(), so
5623 * we must uncharge here.
5625 if (mc.moved_charge) {
5626 cancel_charge(mc.from, mc.moved_charge);
5627 mc.moved_charge = 0;
5629 /* we must fixup refcnts and charges */
5630 if (mc.moved_swap) {
5631 /* uncharge swap account from the old cgroup */
5632 if (!mem_cgroup_is_root(mc.from))
5633 page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
5635 mem_cgroup_id_put_many(mc.from, mc.moved_swap);
5638 * we charged both to->memory and to->memsw, so we
5639 * should uncharge to->memory.
5641 if (!mem_cgroup_is_root(mc.to))
5642 page_counter_uncharge(&mc.to->memory, mc.moved_swap);
5644 mem_cgroup_id_get_many(mc.to, mc.moved_swap);
5645 css_put_many(&mc.to->css, mc.moved_swap);
5649 memcg_oom_recover(from);
5650 memcg_oom_recover(to);
5651 wake_up_all(&mc.waitq);
5654 static void mem_cgroup_clear_mc(void)
5656 struct mm_struct *mm = mc.mm;
5659 * we must clear moving_task before waking up waiters at the end of
5662 mc.moving_task = NULL;
5663 __mem_cgroup_clear_mc();
5664 spin_lock(&mc.lock);
5668 spin_unlock(&mc.lock);
5673 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5675 struct cgroup_subsys_state *css;
5676 struct mem_cgroup *memcg = NULL; /* unneeded init to make gcc happy */
5677 struct mem_cgroup *from;
5678 struct task_struct *leader, *p;
5679 struct mm_struct *mm;
5680 unsigned long move_flags;
5683 /* charge immigration isn't supported on the default hierarchy */
5684 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5688 * Multi-process migrations only happen on the default hierarchy
5689 * where charge immigration is not used. Perform charge
5690 * immigration if @tset contains a leader and whine if there are
5694 cgroup_taskset_for_each_leader(leader, css, tset) {
5697 memcg = mem_cgroup_from_css(css);
5703 * We are now commited to this value whatever it is. Changes in this
5704 * tunable will only affect upcoming migrations, not the current one.
5705 * So we need to save it, and keep it going.
5707 move_flags = READ_ONCE(memcg->move_charge_at_immigrate);
5711 from = mem_cgroup_from_task(p);
5713 VM_BUG_ON(from == memcg);
5715 mm = get_task_mm(p);
5718 /* We move charges only when we move a owner of the mm */
5719 if (mm->owner == p) {
5722 VM_BUG_ON(mc.precharge);
5723 VM_BUG_ON(mc.moved_charge);
5724 VM_BUG_ON(mc.moved_swap);
5726 spin_lock(&mc.lock);
5730 mc.flags = move_flags;
5731 spin_unlock(&mc.lock);
5732 /* We set mc.moving_task later */
5734 ret = mem_cgroup_precharge_mc(mm);
5736 mem_cgroup_clear_mc();
5743 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
5746 mem_cgroup_clear_mc();
5749 static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
5750 unsigned long addr, unsigned long end,
5751 struct mm_walk *walk)
5754 struct vm_area_struct *vma = walk->vma;
5757 enum mc_target_type target_type;
5758 union mc_target target;
5761 ptl = pmd_trans_huge_lock(pmd, vma);
5763 if (mc.precharge < HPAGE_PMD_NR) {
5767 target_type = get_mctgt_type_thp(vma, addr, *pmd, &target);
5768 if (target_type == MC_TARGET_PAGE) {
5770 if (!isolate_lru_page(page)) {
5771 if (!mem_cgroup_move_account(page, true,
5773 mc.precharge -= HPAGE_PMD_NR;
5774 mc.moved_charge += HPAGE_PMD_NR;
5776 putback_lru_page(page);
5779 } else if (target_type == MC_TARGET_DEVICE) {
5781 if (!mem_cgroup_move_account(page, true,
5783 mc.precharge -= HPAGE_PMD_NR;
5784 mc.moved_charge += HPAGE_PMD_NR;
5792 if (pmd_trans_unstable(pmd))
5795 pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
5796 for (; addr != end; addr += PAGE_SIZE) {
5797 pte_t ptent = *(pte++);
5798 bool device = false;
5804 switch (get_mctgt_type(vma, addr, ptent, &target)) {
5805 case MC_TARGET_DEVICE:
5808 case MC_TARGET_PAGE:
5811 * We can have a part of the split pmd here. Moving it
5812 * can be done but it would be too convoluted so simply
5813 * ignore such a partial THP and keep it in original
5814 * memcg. There should be somebody mapping the head.
5816 if (PageTransCompound(page))
5818 if (!device && isolate_lru_page(page))
5820 if (!mem_cgroup_move_account(page, false,
5823 /* we uncharge from mc.from later. */
5827 putback_lru_page(page);
5828 put: /* get_mctgt_type() gets the page */
5831 case MC_TARGET_SWAP:
5833 if (!mem_cgroup_move_swap_account(ent, mc.from, mc.to)) {
5835 /* we fixup refcnts and charges later. */
5843 pte_unmap_unlock(pte - 1, ptl);
5848 * We have consumed all precharges we got in can_attach().
5849 * We try charge one by one, but don't do any additional
5850 * charges to mc.to if we have failed in charge once in attach()
5853 ret = mem_cgroup_do_precharge(1);
5861 static const struct mm_walk_ops charge_walk_ops = {
5862 .pmd_entry = mem_cgroup_move_charge_pte_range,
5865 static void mem_cgroup_move_charge(void)
5867 lru_add_drain_all();
5869 * Signal lock_page_memcg() to take the memcg's move_lock
5870 * while we're moving its pages to another memcg. Then wait
5871 * for already started RCU-only updates to finish.
5873 atomic_inc(&mc.from->moving_account);
5876 if (unlikely(!down_read_trylock(&mc.mm->mmap_sem))) {
5878 * Someone who are holding the mmap_sem might be waiting in
5879 * waitq. So we cancel all extra charges, wake up all waiters,
5880 * and retry. Because we cancel precharges, we might not be able
5881 * to move enough charges, but moving charge is a best-effort
5882 * feature anyway, so it wouldn't be a big problem.
5884 __mem_cgroup_clear_mc();
5889 * When we have consumed all precharges and failed in doing
5890 * additional charge, the page walk just aborts.
5892 walk_page_range(mc.mm, 0, mc.mm->highest_vm_end, &charge_walk_ops,
5895 up_read(&mc.mm->mmap_sem);
5896 atomic_dec(&mc.from->moving_account);
5899 static void mem_cgroup_move_task(void)
5902 mem_cgroup_move_charge();
5903 mem_cgroup_clear_mc();
5906 #else /* !CONFIG_MMU */
5907 static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
5911 static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
5914 static void mem_cgroup_move_task(void)
5920 * Cgroup retains root cgroups across [un]mount cycles making it necessary
5921 * to verify whether we're attached to the default hierarchy on each mount
5924 static void mem_cgroup_bind(struct cgroup_subsys_state *root_css)
5927 * use_hierarchy is forced on the default hierarchy. cgroup core
5928 * guarantees that @root doesn't have any children, so turning it
5929 * on for the root memcg is enough.
5931 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
5932 root_mem_cgroup->use_hierarchy = true;
5934 root_mem_cgroup->use_hierarchy = false;
5937 static int seq_puts_memcg_tunable(struct seq_file *m, unsigned long value)
5939 if (value == PAGE_COUNTER_MAX)
5940 seq_puts(m, "max\n");
5942 seq_printf(m, "%llu\n", (u64)value * PAGE_SIZE);
5947 static u64 memory_current_read(struct cgroup_subsys_state *css,
5950 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
5952 return (u64)page_counter_read(&memcg->memory) * PAGE_SIZE;
5955 static int memory_min_show(struct seq_file *m, void *v)
5957 return seq_puts_memcg_tunable(m,
5958 READ_ONCE(mem_cgroup_from_seq(m)->memory.min));
5961 static ssize_t memory_min_write(struct kernfs_open_file *of,
5962 char *buf, size_t nbytes, loff_t off)
5964 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5968 buf = strstrip(buf);
5969 err = page_counter_memparse(buf, "max", &min);
5973 page_counter_set_min(&memcg->memory, min);
5978 static int memory_low_show(struct seq_file *m, void *v)
5980 return seq_puts_memcg_tunable(m,
5981 READ_ONCE(mem_cgroup_from_seq(m)->memory.low));
5984 static ssize_t memory_low_write(struct kernfs_open_file *of,
5985 char *buf, size_t nbytes, loff_t off)
5987 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
5991 buf = strstrip(buf);
5992 err = page_counter_memparse(buf, "max", &low);
5996 page_counter_set_low(&memcg->memory, low);
6001 static int memory_high_show(struct seq_file *m, void *v)
6003 return seq_puts_memcg_tunable(m, READ_ONCE(mem_cgroup_from_seq(m)->high));
6006 static ssize_t memory_high_write(struct kernfs_open_file *of,
6007 char *buf, size_t nbytes, loff_t off)
6009 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6010 unsigned int nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
6011 bool drained = false;
6015 buf = strstrip(buf);
6016 err = page_counter_memparse(buf, "max", &high);
6020 WRITE_ONCE(memcg->high, high);
6023 unsigned long nr_pages = page_counter_read(&memcg->memory);
6024 unsigned long reclaimed;
6026 if (nr_pages <= high)
6029 if (signal_pending(current))
6033 drain_all_stock(memcg);
6038 reclaimed = try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
6041 if (!reclaimed && !nr_retries--)
6048 static int memory_max_show(struct seq_file *m, void *v)
6050 return seq_puts_memcg_tunable(m,
6051 READ_ONCE(mem_cgroup_from_seq(m)->memory.max));
6054 static ssize_t memory_max_write(struct kernfs_open_file *of,
6055 char *buf, size_t nbytes, loff_t off)
6057 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6058 unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES;
6059 bool drained = false;
6063 buf = strstrip(buf);
6064 err = page_counter_memparse(buf, "max", &max);
6068 xchg(&memcg->memory.max, max);
6071 unsigned long nr_pages = page_counter_read(&memcg->memory);
6073 if (nr_pages <= max)
6076 if (signal_pending(current))
6080 drain_all_stock(memcg);
6086 if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
6092 memcg_memory_event(memcg, MEMCG_OOM);
6093 if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
6097 memcg_wb_domain_size_changed(memcg);
6101 static void __memory_events_show(struct seq_file *m, atomic_long_t *events)
6103 seq_printf(m, "low %lu\n", atomic_long_read(&events[MEMCG_LOW]));
6104 seq_printf(m, "high %lu\n", atomic_long_read(&events[MEMCG_HIGH]));
6105 seq_printf(m, "max %lu\n", atomic_long_read(&events[MEMCG_MAX]));
6106 seq_printf(m, "oom %lu\n", atomic_long_read(&events[MEMCG_OOM]));
6107 seq_printf(m, "oom_kill %lu\n",
6108 atomic_long_read(&events[MEMCG_OOM_KILL]));
6111 static int memory_events_show(struct seq_file *m, void *v)
6113 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6115 __memory_events_show(m, memcg->memory_events);
6119 static int memory_events_local_show(struct seq_file *m, void *v)
6121 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6123 __memory_events_show(m, memcg->memory_events_local);
6127 static int memory_stat_show(struct seq_file *m, void *v)
6129 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6132 buf = memory_stat_format(memcg);
6140 static int memory_oom_group_show(struct seq_file *m, void *v)
6142 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
6144 seq_printf(m, "%d\n", memcg->oom_group);
6149 static ssize_t memory_oom_group_write(struct kernfs_open_file *of,
6150 char *buf, size_t nbytes, loff_t off)
6152 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
6155 buf = strstrip(buf);
6159 ret = kstrtoint(buf, 0, &oom_group);
6163 if (oom_group != 0 && oom_group != 1)
6166 memcg->oom_group = oom_group;
6171 static struct cftype memory_files[] = {
6174 .flags = CFTYPE_NOT_ON_ROOT,
6175 .read_u64 = memory_current_read,
6179 .flags = CFTYPE_NOT_ON_ROOT,
6180 .seq_show = memory_min_show,
6181 .write = memory_min_write,
6185 .flags = CFTYPE_NOT_ON_ROOT,
6186 .seq_show = memory_low_show,
6187 .write = memory_low_write,
6191 .flags = CFTYPE_NOT_ON_ROOT,
6192 .seq_show = memory_high_show,
6193 .write = memory_high_write,
6197 .flags = CFTYPE_NOT_ON_ROOT,
6198 .seq_show = memory_max_show,
6199 .write = memory_max_write,
6203 .flags = CFTYPE_NOT_ON_ROOT,
6204 .file_offset = offsetof(struct mem_cgroup, events_file),
6205 .seq_show = memory_events_show,
6208 .name = "events.local",
6209 .flags = CFTYPE_NOT_ON_ROOT,
6210 .file_offset = offsetof(struct mem_cgroup, events_local_file),
6211 .seq_show = memory_events_local_show,
6215 .flags = CFTYPE_NOT_ON_ROOT,
6216 .seq_show = memory_stat_show,
6219 .name = "oom.group",
6220 .flags = CFTYPE_NOT_ON_ROOT | CFTYPE_NS_DELEGATABLE,
6221 .seq_show = memory_oom_group_show,
6222 .write = memory_oom_group_write,
6227 struct cgroup_subsys memory_cgrp_subsys = {
6228 .css_alloc = mem_cgroup_css_alloc,
6229 .css_online = mem_cgroup_css_online,
6230 .css_offline = mem_cgroup_css_offline,
6231 .css_released = mem_cgroup_css_released,
6232 .css_free = mem_cgroup_css_free,
6233 .css_reset = mem_cgroup_css_reset,
6234 .can_attach = mem_cgroup_can_attach,
6235 .cancel_attach = mem_cgroup_cancel_attach,
6236 .post_attach = mem_cgroup_move_task,
6237 .bind = mem_cgroup_bind,
6238 .dfl_cftypes = memory_files,
6239 .legacy_cftypes = mem_cgroup_legacy_files,
6244 * This function calculates an individual cgroup's effective
6245 * protection which is derived from its own memory.min/low, its
6246 * parent's and siblings' settings, as well as the actual memory
6247 * distribution in the tree.
6249 * The following rules apply to the effective protection values:
6251 * 1. At the first level of reclaim, effective protection is equal to
6252 * the declared protection in memory.min and memory.low.
6254 * 2. To enable safe delegation of the protection configuration, at
6255 * subsequent levels the effective protection is capped to the
6256 * parent's effective protection.
6258 * 3. To make complex and dynamic subtrees easier to configure, the
6259 * user is allowed to overcommit the declared protection at a given
6260 * level. If that is the case, the parent's effective protection is
6261 * distributed to the children in proportion to how much protection
6262 * they have declared and how much of it they are utilizing.
6264 * This makes distribution proportional, but also work-conserving:
6265 * if one cgroup claims much more protection than it uses memory,
6266 * the unused remainder is available to its siblings.
6268 * 4. Conversely, when the declared protection is undercommitted at a
6269 * given level, the distribution of the larger parental protection
6270 * budget is NOT proportional. A cgroup's protection from a sibling
6271 * is capped to its own memory.min/low setting.
6273 * 5. However, to allow protecting recursive subtrees from each other
6274 * without having to declare each individual cgroup's fixed share
6275 * of the ancestor's claim to protection, any unutilized -
6276 * "floating" - protection from up the tree is distributed in
6277 * proportion to each cgroup's *usage*. This makes the protection
6278 * neutral wrt sibling cgroups and lets them compete freely over
6279 * the shared parental protection budget, but it protects the
6280 * subtree as a whole from neighboring subtrees.
6282 * Note that 4. and 5. are not in conflict: 4. is about protecting
6283 * against immediate siblings whereas 5. is about protecting against
6284 * neighboring subtrees.
6286 static unsigned long effective_protection(unsigned long usage,
6287 unsigned long parent_usage,
6288 unsigned long setting,
6289 unsigned long parent_effective,
6290 unsigned long siblings_protected)
6292 unsigned long protected;
6295 protected = min(usage, setting);
6297 * If all cgroups at this level combined claim and use more
6298 * protection then what the parent affords them, distribute
6299 * shares in proportion to utilization.
6301 * We are using actual utilization rather than the statically
6302 * claimed protection in order to be work-conserving: claimed
6303 * but unused protection is available to siblings that would
6304 * otherwise get a smaller chunk than what they claimed.
6306 if (siblings_protected > parent_effective)
6307 return protected * parent_effective / siblings_protected;
6310 * Ok, utilized protection of all children is within what the
6311 * parent affords them, so we know whatever this child claims
6312 * and utilizes is effectively protected.
6314 * If there is unprotected usage beyond this value, reclaim
6315 * will apply pressure in proportion to that amount.
6317 * If there is unutilized protection, the cgroup will be fully
6318 * shielded from reclaim, but we do return a smaller value for
6319 * protection than what the group could enjoy in theory. This
6320 * is okay. With the overcommit distribution above, effective
6321 * protection is always dependent on how memory is actually
6322 * consumed among the siblings anyway.
6327 * If the children aren't claiming (all of) the protection
6328 * afforded to them by the parent, distribute the remainder in
6329 * proportion to the (unprotected) memory of each cgroup. That
6330 * way, cgroups that aren't explicitly prioritized wrt each
6331 * other compete freely over the allowance, but they are
6332 * collectively protected from neighboring trees.
6334 * We're using unprotected memory for the weight so that if
6335 * some cgroups DO claim explicit protection, we don't protect
6336 * the same bytes twice.
6338 if (!(cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_RECURSIVE_PROT))
6341 if (parent_effective > siblings_protected && usage > protected) {
6342 unsigned long unclaimed;
6344 unclaimed = parent_effective - siblings_protected;
6345 unclaimed *= usage - protected;
6346 unclaimed /= parent_usage - siblings_protected;
6355 * mem_cgroup_protected - check if memory consumption is in the normal range
6356 * @root: the top ancestor of the sub-tree being checked
6357 * @memcg: the memory cgroup to check
6359 * WARNING: This function is not stateless! It can only be used as part
6360 * of a top-down tree iteration, not for isolated queries.
6362 * Returns one of the following:
6363 * MEMCG_PROT_NONE: cgroup memory is not protected
6364 * MEMCG_PROT_LOW: cgroup memory is protected as long there is
6365 * an unprotected supply of reclaimable memory from other cgroups.
6366 * MEMCG_PROT_MIN: cgroup memory is protected
6368 enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root,
6369 struct mem_cgroup *memcg)
6371 unsigned long usage, parent_usage;
6372 struct mem_cgroup *parent;
6374 if (mem_cgroup_disabled())
6375 return MEMCG_PROT_NONE;
6378 root = root_mem_cgroup;
6380 return MEMCG_PROT_NONE;
6382 usage = page_counter_read(&memcg->memory);
6384 return MEMCG_PROT_NONE;
6386 parent = parent_mem_cgroup(memcg);
6387 /* No parent means a non-hierarchical mode on v1 memcg */
6389 return MEMCG_PROT_NONE;
6391 if (parent == root) {
6392 memcg->memory.emin = memcg->memory.min;
6393 memcg->memory.elow = memcg->memory.low;
6397 parent_usage = page_counter_read(&parent->memory);
6399 memcg->memory.emin = effective_protection(usage, parent_usage,
6400 memcg->memory.min, READ_ONCE(parent->memory.emin),
6401 atomic_long_read(&parent->memory.children_min_usage));
6403 memcg->memory.elow = effective_protection(usage, parent_usage,
6404 memcg->memory.low, READ_ONCE(parent->memory.elow),
6405 atomic_long_read(&parent->memory.children_low_usage));
6408 if (usage <= memcg->memory.emin)
6409 return MEMCG_PROT_MIN;
6410 else if (usage <= memcg->memory.elow)
6411 return MEMCG_PROT_LOW;
6413 return MEMCG_PROT_NONE;
6417 * mem_cgroup_try_charge - try charging a page
6418 * @page: page to charge
6419 * @mm: mm context of the victim
6420 * @gfp_mask: reclaim mode
6421 * @memcgp: charged memcg return
6422 * @compound: charge the page as compound or small page
6424 * Try to charge @page to the memcg that @mm belongs to, reclaiming
6425 * pages according to @gfp_mask if necessary.
6427 * Returns 0 on success, with *@memcgp pointing to the charged memcg.
6428 * Otherwise, an error code is returned.
6430 * After page->mapping has been set up, the caller must finalize the
6431 * charge with mem_cgroup_commit_charge(). Or abort the transaction
6432 * with mem_cgroup_cancel_charge() in case page instantiation fails.
6434 int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm,
6435 gfp_t gfp_mask, struct mem_cgroup **memcgp,
6438 struct mem_cgroup *memcg = NULL;
6439 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
6442 if (mem_cgroup_disabled())
6445 if (PageSwapCache(page)) {
6447 * Every swap fault against a single page tries to charge the
6448 * page, bail as early as possible. shmem_unuse() encounters
6449 * already charged pages, too. The USED bit is protected by
6450 * the page lock, which serializes swap cache removal, which
6451 * in turn serializes uncharging.
6453 VM_BUG_ON_PAGE(!PageLocked(page), page);
6454 if (compound_head(page)->mem_cgroup)
6457 if (do_swap_account) {
6458 swp_entry_t ent = { .val = page_private(page), };
6459 unsigned short id = lookup_swap_cgroup_id(ent);
6462 memcg = mem_cgroup_from_id(id);
6463 if (memcg && !css_tryget_online(&memcg->css))
6470 memcg = get_mem_cgroup_from_mm(mm);
6472 ret = try_charge(memcg, gfp_mask, nr_pages);
6474 css_put(&memcg->css);
6480 int mem_cgroup_try_charge_delay(struct page *page, struct mm_struct *mm,
6481 gfp_t gfp_mask, struct mem_cgroup **memcgp,
6484 struct mem_cgroup *memcg;
6487 ret = mem_cgroup_try_charge(page, mm, gfp_mask, memcgp, compound);
6489 mem_cgroup_throttle_swaprate(memcg, page_to_nid(page), gfp_mask);
6494 * mem_cgroup_commit_charge - commit a page charge
6495 * @page: page to charge
6496 * @memcg: memcg to charge the page to
6497 * @lrucare: page might be on LRU already
6498 * @compound: charge the page as compound or small page
6500 * Finalize a charge transaction started by mem_cgroup_try_charge(),
6501 * after page->mapping has been set up. This must happen atomically
6502 * as part of the page instantiation, i.e. under the page table lock
6503 * for anonymous pages, under the page lock for page and swap cache.
6505 * In addition, the page must not be on the LRU during the commit, to
6506 * prevent racing with task migration. If it might be, use @lrucare.
6508 * Use mem_cgroup_cancel_charge() to cancel the transaction instead.
6510 void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg,
6511 bool lrucare, bool compound)
6513 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
6515 VM_BUG_ON_PAGE(!page->mapping, page);
6516 VM_BUG_ON_PAGE(PageLRU(page) && !lrucare, page);
6518 if (mem_cgroup_disabled())
6521 * Swap faults will attempt to charge the same page multiple
6522 * times. But reuse_swap_page() might have removed the page
6523 * from swapcache already, so we can't check PageSwapCache().
6528 commit_charge(page, memcg, lrucare);
6530 local_irq_disable();
6531 mem_cgroup_charge_statistics(memcg, page, compound, nr_pages);
6532 memcg_check_events(memcg, page);
6535 if (do_memsw_account() && PageSwapCache(page)) {
6536 swp_entry_t entry = { .val = page_private(page) };
6538 * The swap entry might not get freed for a long time,
6539 * let's not wait for it. The page already received a
6540 * memory+swap charge, drop the swap entry duplicate.
6542 mem_cgroup_uncharge_swap(entry, nr_pages);
6547 * mem_cgroup_cancel_charge - cancel a page charge
6548 * @page: page to charge
6549 * @memcg: memcg to charge the page to
6550 * @compound: charge the page as compound or small page
6552 * Cancel a charge transaction started by mem_cgroup_try_charge().
6554 void mem_cgroup_cancel_charge(struct page *page, struct mem_cgroup *memcg,
6557 unsigned int nr_pages = compound ? hpage_nr_pages(page) : 1;
6559 if (mem_cgroup_disabled())
6562 * Swap faults will attempt to charge the same page multiple
6563 * times. But reuse_swap_page() might have removed the page
6564 * from swapcache already, so we can't check PageSwapCache().
6569 cancel_charge(memcg, nr_pages);
6572 struct uncharge_gather {
6573 struct mem_cgroup *memcg;
6574 unsigned long pgpgout;
6575 unsigned long nr_anon;
6576 unsigned long nr_file;
6577 unsigned long nr_kmem;
6578 unsigned long nr_huge;
6579 unsigned long nr_shmem;
6580 struct page *dummy_page;
6583 static inline void uncharge_gather_clear(struct uncharge_gather *ug)
6585 memset(ug, 0, sizeof(*ug));
6588 static void uncharge_batch(const struct uncharge_gather *ug)
6590 unsigned long nr_pages = ug->nr_anon + ug->nr_file + ug->nr_kmem;
6591 unsigned long flags;
6593 if (!mem_cgroup_is_root(ug->memcg)) {
6594 page_counter_uncharge(&ug->memcg->memory, nr_pages);
6595 if (do_memsw_account())
6596 page_counter_uncharge(&ug->memcg->memsw, nr_pages);
6597 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && ug->nr_kmem)
6598 page_counter_uncharge(&ug->memcg->kmem, ug->nr_kmem);
6599 memcg_oom_recover(ug->memcg);
6602 local_irq_save(flags);
6603 __mod_memcg_state(ug->memcg, MEMCG_RSS, -ug->nr_anon);
6604 __mod_memcg_state(ug->memcg, MEMCG_CACHE, -ug->nr_file);
6605 __mod_memcg_state(ug->memcg, MEMCG_RSS_HUGE, -ug->nr_huge);
6606 __mod_memcg_state(ug->memcg, NR_SHMEM, -ug->nr_shmem);
6607 __count_memcg_events(ug->memcg, PGPGOUT, ug->pgpgout);
6608 __this_cpu_add(ug->memcg->vmstats_percpu->nr_page_events, nr_pages);
6609 memcg_check_events(ug->memcg, ug->dummy_page);
6610 local_irq_restore(flags);
6612 if (!mem_cgroup_is_root(ug->memcg))
6613 css_put_many(&ug->memcg->css, nr_pages);
6616 static void uncharge_page(struct page *page, struct uncharge_gather *ug)
6618 VM_BUG_ON_PAGE(PageLRU(page), page);
6619 VM_BUG_ON_PAGE(page_count(page) && !is_zone_device_page(page) &&
6620 !PageHWPoison(page) , page);
6622 if (!page->mem_cgroup)
6626 * Nobody should be changing or seriously looking at
6627 * page->mem_cgroup at this point, we have fully
6628 * exclusive access to the page.
6631 if (ug->memcg != page->mem_cgroup) {
6634 uncharge_gather_clear(ug);
6636 ug->memcg = page->mem_cgroup;
6639 if (!PageKmemcg(page)) {
6640 unsigned int nr_pages = 1;
6642 if (PageTransHuge(page)) {
6643 nr_pages = compound_nr(page);
6644 ug->nr_huge += nr_pages;
6647 ug->nr_anon += nr_pages;
6649 ug->nr_file += nr_pages;
6650 if (PageSwapBacked(page))
6651 ug->nr_shmem += nr_pages;
6655 ug->nr_kmem += compound_nr(page);
6656 __ClearPageKmemcg(page);
6659 ug->dummy_page = page;
6660 page->mem_cgroup = NULL;
6663 static void uncharge_list(struct list_head *page_list)
6665 struct uncharge_gather ug;
6666 struct list_head *next;
6668 uncharge_gather_clear(&ug);
6671 * Note that the list can be a single page->lru; hence the
6672 * do-while loop instead of a simple list_for_each_entry().
6674 next = page_list->next;
6678 page = list_entry(next, struct page, lru);
6679 next = page->lru.next;
6681 uncharge_page(page, &ug);
6682 } while (next != page_list);
6685 uncharge_batch(&ug);
6689 * mem_cgroup_uncharge - uncharge a page
6690 * @page: page to uncharge
6692 * Uncharge a page previously charged with mem_cgroup_try_charge() and
6693 * mem_cgroup_commit_charge().
6695 void mem_cgroup_uncharge(struct page *page)
6697 struct uncharge_gather ug;
6699 if (mem_cgroup_disabled())
6702 /* Don't touch page->lru of any random page, pre-check: */
6703 if (!page->mem_cgroup)
6706 uncharge_gather_clear(&ug);
6707 uncharge_page(page, &ug);
6708 uncharge_batch(&ug);
6712 * mem_cgroup_uncharge_list - uncharge a list of page
6713 * @page_list: list of pages to uncharge
6715 * Uncharge a list of pages previously charged with
6716 * mem_cgroup_try_charge() and mem_cgroup_commit_charge().
6718 void mem_cgroup_uncharge_list(struct list_head *page_list)
6720 if (mem_cgroup_disabled())
6723 if (!list_empty(page_list))
6724 uncharge_list(page_list);
6728 * mem_cgroup_migrate - charge a page's replacement
6729 * @oldpage: currently circulating page
6730 * @newpage: replacement page
6732 * Charge @newpage as a replacement page for @oldpage. @oldpage will
6733 * be uncharged upon free.
6735 * Both pages must be locked, @newpage->mapping must be set up.
6737 void mem_cgroup_migrate(struct page *oldpage, struct page *newpage)
6739 struct mem_cgroup *memcg;
6740 unsigned int nr_pages;
6741 unsigned long flags;
6743 VM_BUG_ON_PAGE(!PageLocked(oldpage), oldpage);
6744 VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);
6745 VM_BUG_ON_PAGE(PageAnon(oldpage) != PageAnon(newpage), newpage);
6746 VM_BUG_ON_PAGE(PageTransHuge(oldpage) != PageTransHuge(newpage),
6749 if (mem_cgroup_disabled())
6752 /* Page cache replacement: new page already charged? */
6753 if (newpage->mem_cgroup)
6756 /* Swapcache readahead pages can get replaced before being charged */
6757 memcg = oldpage->mem_cgroup;
6761 /* Force-charge the new page. The old one will be freed soon */
6762 nr_pages = hpage_nr_pages(newpage);
6764 page_counter_charge(&memcg->memory, nr_pages);
6765 if (do_memsw_account())
6766 page_counter_charge(&memcg->memsw, nr_pages);
6767 css_get_many(&memcg->css, nr_pages);
6769 commit_charge(newpage, memcg, false);
6771 local_irq_save(flags);
6772 mem_cgroup_charge_statistics(memcg, newpage, PageTransHuge(newpage),
6774 memcg_check_events(memcg, newpage);
6775 local_irq_restore(flags);
6778 DEFINE_STATIC_KEY_FALSE(memcg_sockets_enabled_key);
6779 EXPORT_SYMBOL(memcg_sockets_enabled_key);
6781 void mem_cgroup_sk_alloc(struct sock *sk)
6783 struct mem_cgroup *memcg;
6785 if (!mem_cgroup_sockets_enabled)
6788 /* Do not associate the sock with unrelated interrupted task's memcg. */
6793 memcg = mem_cgroup_from_task(current);
6794 if (memcg == root_mem_cgroup)
6796 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) && !memcg->tcpmem_active)
6798 if (css_tryget(&memcg->css))
6799 sk->sk_memcg = memcg;
6804 void mem_cgroup_sk_free(struct sock *sk)
6807 css_put(&sk->sk_memcg->css);
6811 * mem_cgroup_charge_skmem - charge socket memory
6812 * @memcg: memcg to charge
6813 * @nr_pages: number of pages to charge
6815 * Charges @nr_pages to @memcg. Returns %true if the charge fit within
6816 * @memcg's configured limit, %false if the charge had to be forced.
6818 bool mem_cgroup_charge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
6820 gfp_t gfp_mask = GFP_KERNEL;
6822 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
6823 struct page_counter *fail;
6825 if (page_counter_try_charge(&memcg->tcpmem, nr_pages, &fail)) {
6826 memcg->tcpmem_pressure = 0;
6829 page_counter_charge(&memcg->tcpmem, nr_pages);
6830 memcg->tcpmem_pressure = 1;
6834 /* Don't block in the packet receive path */
6836 gfp_mask = GFP_NOWAIT;
6838 mod_memcg_state(memcg, MEMCG_SOCK, nr_pages);
6840 if (try_charge(memcg, gfp_mask, nr_pages) == 0)
6843 try_charge(memcg, gfp_mask|__GFP_NOFAIL, nr_pages);
6848 * mem_cgroup_uncharge_skmem - uncharge socket memory
6849 * @memcg: memcg to uncharge
6850 * @nr_pages: number of pages to uncharge
6852 void mem_cgroup_uncharge_skmem(struct mem_cgroup *memcg, unsigned int nr_pages)
6854 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys)) {
6855 page_counter_uncharge(&memcg->tcpmem, nr_pages);
6859 mod_memcg_state(memcg, MEMCG_SOCK, -nr_pages);
6861 refill_stock(memcg, nr_pages);
6864 static int __init cgroup_memory(char *s)
6868 while ((token = strsep(&s, ",")) != NULL) {
6871 if (!strcmp(token, "nosocket"))
6872 cgroup_memory_nosocket = true;
6873 if (!strcmp(token, "nokmem"))
6874 cgroup_memory_nokmem = true;
6878 __setup("cgroup.memory=", cgroup_memory);
6881 * subsys_initcall() for memory controller.
6883 * Some parts like memcg_hotplug_cpu_dead() have to be initialized from this
6884 * context because of lock dependencies (cgroup_lock -> cpu hotplug) but
6885 * basically everything that doesn't depend on a specific mem_cgroup structure
6886 * should be initialized from here.
6888 static int __init mem_cgroup_init(void)
6892 #ifdef CONFIG_MEMCG_KMEM
6894 * Kmem cache creation is mostly done with the slab_mutex held,
6895 * so use a workqueue with limited concurrency to avoid stalling
6896 * all worker threads in case lots of cgroups are created and
6897 * destroyed simultaneously.
6899 memcg_kmem_cache_wq = alloc_workqueue("memcg_kmem_cache", 0, 1);
6900 BUG_ON(!memcg_kmem_cache_wq);
6903 cpuhp_setup_state_nocalls(CPUHP_MM_MEMCQ_DEAD, "mm/memctrl:dead", NULL,
6904 memcg_hotplug_cpu_dead);
6906 for_each_possible_cpu(cpu)
6907 INIT_WORK(&per_cpu_ptr(&memcg_stock, cpu)->work,
6910 for_each_node(node) {
6911 struct mem_cgroup_tree_per_node *rtpn;
6913 rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL,
6914 node_online(node) ? node : NUMA_NO_NODE);
6916 rtpn->rb_root = RB_ROOT;
6917 rtpn->rb_rightmost = NULL;
6918 spin_lock_init(&rtpn->lock);
6919 soft_limit_tree.rb_tree_per_node[node] = rtpn;
6924 subsys_initcall(mem_cgroup_init);
6926 #ifdef CONFIG_MEMCG_SWAP
6927 static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
6929 while (!refcount_inc_not_zero(&memcg->id.ref)) {
6931 * The root cgroup cannot be destroyed, so it's refcount must
6934 if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
6938 memcg = parent_mem_cgroup(memcg);
6940 memcg = root_mem_cgroup;
6946 * mem_cgroup_swapout - transfer a memsw charge to swap
6947 * @page: page whose memsw charge to transfer
6948 * @entry: swap entry to move the charge to
6950 * Transfer the memsw charge of @page to @entry.
6952 void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
6954 struct mem_cgroup *memcg, *swap_memcg;
6955 unsigned int nr_entries;
6956 unsigned short oldid;
6958 VM_BUG_ON_PAGE(PageLRU(page), page);
6959 VM_BUG_ON_PAGE(page_count(page), page);
6961 if (!do_memsw_account())
6964 memcg = page->mem_cgroup;
6966 /* Readahead page, never charged */
6971 * In case the memcg owning these pages has been offlined and doesn't
6972 * have an ID allocated to it anymore, charge the closest online
6973 * ancestor for the swap instead and transfer the memory+swap charge.
6975 swap_memcg = mem_cgroup_id_get_online(memcg);
6976 nr_entries = hpage_nr_pages(page);
6977 /* Get references for the tail pages, too */
6979 mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
6980 oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
6982 VM_BUG_ON_PAGE(oldid, page);
6983 mod_memcg_state(swap_memcg, MEMCG_SWAP, nr_entries);
6985 page->mem_cgroup = NULL;
6987 if (!mem_cgroup_is_root(memcg))
6988 page_counter_uncharge(&memcg->memory, nr_entries);
6990 if (memcg != swap_memcg) {
6991 if (!mem_cgroup_is_root(swap_memcg))
6992 page_counter_charge(&swap_memcg->memsw, nr_entries);
6993 page_counter_uncharge(&memcg->memsw, nr_entries);
6997 * Interrupts should be disabled here because the caller holds the
6998 * i_pages lock which is taken with interrupts-off. It is
6999 * important here to have the interrupts disabled because it is the
7000 * only synchronisation we have for updating the per-CPU variables.
7002 VM_BUG_ON(!irqs_disabled());
7003 mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
7005 memcg_check_events(memcg, page);
7007 if (!mem_cgroup_is_root(memcg))
7008 css_put_many(&memcg->css, nr_entries);
7012 * mem_cgroup_try_charge_swap - try charging swap space for a page
7013 * @page: page being added to swap
7014 * @entry: swap entry to charge
7016 * Try to charge @page's memcg for the swap space at @entry.
7018 * Returns 0 on success, -ENOMEM on failure.
7020 int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
7022 unsigned int nr_pages = hpage_nr_pages(page);
7023 struct page_counter *counter;
7024 struct mem_cgroup *memcg;
7025 unsigned short oldid;
7027 if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !do_swap_account)
7030 memcg = page->mem_cgroup;
7032 /* Readahead page, never charged */
7037 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7041 memcg = mem_cgroup_id_get_online(memcg);
7043 if (!mem_cgroup_is_root(memcg) &&
7044 !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) {
7045 memcg_memory_event(memcg, MEMCG_SWAP_MAX);
7046 memcg_memory_event(memcg, MEMCG_SWAP_FAIL);
7047 mem_cgroup_id_put(memcg);
7051 /* Get references for the tail pages, too */
7053 mem_cgroup_id_get_many(memcg, nr_pages - 1);
7054 oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg), nr_pages);
7055 VM_BUG_ON_PAGE(oldid, page);
7056 mod_memcg_state(memcg, MEMCG_SWAP, nr_pages);
7062 * mem_cgroup_uncharge_swap - uncharge swap space
7063 * @entry: swap entry to uncharge
7064 * @nr_pages: the amount of swap space to uncharge
7066 void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
7068 struct mem_cgroup *memcg;
7071 if (!do_swap_account)
7074 id = swap_cgroup_record(entry, 0, nr_pages);
7076 memcg = mem_cgroup_from_id(id);
7078 if (!mem_cgroup_is_root(memcg)) {
7079 if (cgroup_subsys_on_dfl(memory_cgrp_subsys))
7080 page_counter_uncharge(&memcg->swap, nr_pages);
7082 page_counter_uncharge(&memcg->memsw, nr_pages);
7084 mod_memcg_state(memcg, MEMCG_SWAP, -nr_pages);
7085 mem_cgroup_id_put_many(memcg, nr_pages);
7090 long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
7092 long nr_swap_pages = get_nr_swap_pages();
7094 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7095 return nr_swap_pages;
7096 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
7097 nr_swap_pages = min_t(long, nr_swap_pages,
7098 READ_ONCE(memcg->swap.max) -
7099 page_counter_read(&memcg->swap));
7100 return nr_swap_pages;
7103 bool mem_cgroup_swap_full(struct page *page)
7105 struct mem_cgroup *memcg;
7107 VM_BUG_ON_PAGE(!PageLocked(page), page);
7111 if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
7114 memcg = page->mem_cgroup;
7118 for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
7119 if (page_counter_read(&memcg->swap) * 2 >= memcg->swap.max)
7125 /* for remember boot option*/
7126 #ifdef CONFIG_MEMCG_SWAP_ENABLED
7127 static int really_do_swap_account __initdata = 1;
7129 static int really_do_swap_account __initdata;
7132 static int __init enable_swap_account(char *s)
7134 if (!strcmp(s, "1"))
7135 really_do_swap_account = 1;
7136 else if (!strcmp(s, "0"))
7137 really_do_swap_account = 0;
7140 __setup("swapaccount=", enable_swap_account);
7142 static u64 swap_current_read(struct cgroup_subsys_state *css,
7145 struct mem_cgroup *memcg = mem_cgroup_from_css(css);
7147 return (u64)page_counter_read(&memcg->swap) * PAGE_SIZE;
7150 static int swap_max_show(struct seq_file *m, void *v)
7152 return seq_puts_memcg_tunable(m,
7153 READ_ONCE(mem_cgroup_from_seq(m)->swap.max));
7156 static ssize_t swap_max_write(struct kernfs_open_file *of,
7157 char *buf, size_t nbytes, loff_t off)
7159 struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
7163 buf = strstrip(buf);
7164 err = page_counter_memparse(buf, "max", &max);
7168 xchg(&memcg->swap.max, max);
7173 static int swap_events_show(struct seq_file *m, void *v)
7175 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
7177 seq_printf(m, "max %lu\n",
7178 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_MAX]));
7179 seq_printf(m, "fail %lu\n",
7180 atomic_long_read(&memcg->memory_events[MEMCG_SWAP_FAIL]));
7185 static struct cftype swap_files[] = {
7187 .name = "swap.current",
7188 .flags = CFTYPE_NOT_ON_ROOT,
7189 .read_u64 = swap_current_read,
7193 .flags = CFTYPE_NOT_ON_ROOT,
7194 .seq_show = swap_max_show,
7195 .write = swap_max_write,
7198 .name = "swap.events",
7199 .flags = CFTYPE_NOT_ON_ROOT,
7200 .file_offset = offsetof(struct mem_cgroup, swap_events_file),
7201 .seq_show = swap_events_show,
7206 static struct cftype memsw_cgroup_files[] = {
7208 .name = "memsw.usage_in_bytes",
7209 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
7210 .read_u64 = mem_cgroup_read_u64,
7213 .name = "memsw.max_usage_in_bytes",
7214 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_MAX_USAGE),
7215 .write = mem_cgroup_reset,
7216 .read_u64 = mem_cgroup_read_u64,
7219 .name = "memsw.limit_in_bytes",
7220 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_LIMIT),
7221 .write = mem_cgroup_write,
7222 .read_u64 = mem_cgroup_read_u64,
7225 .name = "memsw.failcnt",
7226 .private = MEMFILE_PRIVATE(_MEMSWAP, RES_FAILCNT),
7227 .write = mem_cgroup_reset,
7228 .read_u64 = mem_cgroup_read_u64,
7230 { }, /* terminate */
7233 static int __init mem_cgroup_swap_init(void)
7235 if (!mem_cgroup_disabled() && really_do_swap_account) {
7236 do_swap_account = 1;
7237 WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
7239 WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
7240 memsw_cgroup_files));
7244 subsys_initcall(mem_cgroup_swap_init);
7246 #endif /* CONFIG_MEMCG_SWAP */